AI Trajectory

Trajectory: (Expand/Collapse All)
Seq	Timestamp	Type	Name	Duration
0/0	2026/09/30 04:56	flow	patch-triage	4m Args: null Results: { "EnableConfigs": [ "NFS_FS", "NFS_V4" ], "FocusSymbols": [ "nfs_atomic_open", "nfs_rename", "nfs_link", "nfs_sillyrename", "nfs_prime_dcache", "nfs_lookup_revalidate", "block_revalidate", "nfs_call_unlink", "_nfs4_open_and_get_state" ], "KMSANReasoning": "The patch refactors NFS dentry handling and concurrency control across lookup, atomic_open, link, sillyrename, and unlink operations. Specifically, it adopts dcache helpers such as d_alloc_trylock(), d_duplicate(), and d_splice_alias(), refines dentry invalidation (including sequence count invalidation in block_revalidate()), and ensures proper hashing in nfs_call_unlink().\n\nNo uninitialized memory hazards are introduced or exposed:\n1. No kernel structures or data buffers are copied to user space (no copy_to_user, put_user, netlink messages, ioctls, or socket options).\n2. All local variables touched or introduced (such as 'sdentry', 'old', 'silly') are fully initialized before use.\n3. The changes operate entirely on dentry reference counting, lookup states, and VFS synchronization.\n\nAny bugs that might arise from these modifications would involve locking deadlocks, sequence count inconsistencies, use-after-free, or refcount imbalances on dentries and inodes—all of which are caught by standard KASAN, LOCKDEP, and kernel debug assertions. Thus, dedicated KMSAN fuzzing is not justified.", "NeedsKMSAN": false, "Reasoning": "The patch modifies core NFS client directory and dentry lifecycle operations across fs/nfs/dir.c, fs/nfs/unlink.c, and fs/nfs/nfs4proc.c. Changes include switching to d_alloc_trylock and d_duplicate, adding write_seqcount_invalidate in block_revalidate, altering negative dentry revalidation for LOOKUP_OPEN, rewriting the silly-rename lookup loop, and adjusting d_splice_alias and d_drop error/success paths in nfs_atomic_open and nfs_link. These concurrent VFS/NFS dcache synchronization operations are reachable and prone to race conditions, refcounting issues, and regressions, making them well worth fuzzing.", "WorthFuzzing": true }
1/1	2026/09/30 04:56	action	read-patch-diff	0m Args: null Results: { "PatchDiff": "commit 493eaeb9f60ffc74be93a90611ccdebd6ea2a7b7\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Wed Sep 30 04:56:38 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/fs/nfs/dir.c b/fs/nfs/dir.c\nindex 49394123bd096..3adb8ce727f8f 100644\n--- a/fs/nfs/dir.c\n+++ b/fs/nfs/dir.c\n@@ -749,15 +749,12 @@ void nfs_prime_dcache(struct dentry parent, struct nfs_entry entry,\n \t\tif (filename.len == 2 \u0026\u0026 filename.name[1] == '.')\n \t\t\treturn;\n \t}\n-\tfilename.hash = full_name_hash(parent, filename.name, filename.len);\n \n-\tdentry = d_lookup(parent, \u0026filename);\n again:\n-\tif (!dentry) {\n-\t\tdentry = d_alloc_parallel(parent, \u0026filename);\n-\t\tif (IS_ERR(dentry))\n-\t\t\treturn;\n-\t}\n+\tdentry = d_alloc_trylock(parent, \u0026filename);\n+\tif (IS_ERR(dentry))\n+\t\treturn;\n+\n \tif (!d_in_lookup(dentry)) {\n \t\t/* Is there a mountpoint here? If so, just exit /\n \t\tif (!nfs_fsid_equal(\u0026NFS_SB(dentry-\u003ed_sb)-\u003efsid,\n@@ -1570,6 +1567,9 @@ static int nfs_check_verifier(struct inode dir, struct dentry dentry,\n /\n * Use intent information to check whether or not we're going to do\n * an O_EXCL create using this path component.\n+ * Note that link(), mkdir(), mknod(), symlink() all appear as\n+ * exclusive creation. Regular file creation could be distinguished\n+ * with LOOKUP_OPEN.\n /\n static int nfs_is_exclusive_create(struct inode dir, unsigned int flags)\n {\n@@ -1656,6 +1656,13 @@ int nfs_neg_need_reval(struct inode dir, struct dentry dentry,\n {\n \tif (flags \u0026 (LOOKUP_CREATE \| LOOKUP_RENAME_TARGET))\n \t\treturn 0;\n+\tif (flags \u0026 LOOKUP_OPEN)\n+\t\t/* close-to-open semantics require we go to the server\n+\t\t * on each open. By invalidating the dentry we\n+\t\t * also ensure nfs_atomic_open() always has exclusive\n+\t\t * access to the dentry.\n+\t\t /\n+\t\treturn 1;\n \tif (NFS_SERVER(dir)-\u003eflags \u0026 NFS_MOUNT_LOOKUP_CACHE_NONEG)\n \t\treturn 1;\n \t/ Case insensitive server? Revalidate negative dentries /\n@@ -1837,8 +1844,7 @@ __nfs_lookup_revalidate(struct dentry dentry, unsigned int flags)\n \t} else {\n \t\t/* Wait for unlink to complete - see unblock_revalidate() /\n \t\twait_var_event(\u0026dentry-\u003ed_fsdata,\n-\t\t\t smp_load_acquire(\u0026dentry-\u003ed_fsdata)\n-\t\t\t != NFS_FSDATA_BLOCKED);\n+\t\t\t dentry-\u003ed_fsdata != NFS_FSDATA_BLOCKED);\n \t}\n \treturn 0;\n }\n@@ -1857,12 +1863,15 @@ static void block_revalidate(struct dentry dentry)\n \tkfree(dentry-\u003ed_fsdata);\n \n \t/* Any new reference that could lead to an open\n-\t * will take -\u003ed_lock in lookup_open() -\u003e d_lookup().\n-\t * Holding this lock ensures we cannot race with\n-\t * __nfs_lookup_revalidate() and removes and need\n-\t * for further barriers.\n+\t * will either:\n+\t * - take -\u003ed_lock in lookup_open() -\u003e d_lookup() or\n+\t * - will check d_seq in legitimize_mnt()\n+\t \n+\t Holding this lock and invalidating -\u003ed_seq ensures we cannot\n+\t * race with __nfs_lookup_revalidate().\n \t /\n \tlockdep_assert_held(\u0026dentry-\u003ed_lock);\n+\twrite_seqcount_invalidate(\u0026dentry-\u003ed_seq);\n \n \tdentry-\u003ed_fsdata = NFS_FSDATA_BLOCKED;\n }\n@@ -2111,7 +2120,6 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry,\n \tstruct inode inode;\n \tunsigned int lookup_flags = 0;\n \tunsigned long dir_verifier;\n-\tbool switched = false;\n \tint created = 0;\n \tint err;\n \n@@ -2156,17 +2164,6 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry,\n \t\tattr.ia_size = 0;\n \t}\n \n-\tif (!(open_flags \u0026 O_CREAT) \u0026\u0026 !d_in_lookup(dentry)) {\n-\t\td_drop(dentry);\n-\t\tswitched = true;\n-\t\tdentry = d_alloc_parallel(dentry-\u003ed_parent,\n-\t\t\t\t\t \u0026dentry-\u003ed_name);\n-\t\tif (IS_ERR(dentry))\n-\t\t\treturn PTR_ERR(dentry);\n-\t\tif (unlikely(!d_in_lookup(dentry)))\n-\t\t\treturn finish_no_open(file, dentry);\n-\t}\n-\n \tctx = create_nfs_open_context(dentry, open_flags, file);\n \terr = PTR_ERR(ctx);\n \tif (IS_ERR(ctx))\n@@ -2180,7 +2177,6 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry,\n \t\terr = PTR_ERR(inode);\n \t\ttrace_nfs_atomic_open_exit(dir, ctx, open_flags, err);\n \t\tput_nfs_open_context(ctx);\n-\t\td_drop(dentry);\n \t\tswitch (err) {\n \t\tcase -ENOENT:\n \t\t\tif (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE))\n@@ -2189,7 +2185,7 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry,\n \t\t\t\tdir_verifier = nfs_save_change_attribute(dir);\n \t\t\tnfs_set_verifier(dentry, dir_verifier);\n \t\t\td_splice_alias(NULL, dentry);\n-\t\t\tbreak;\n+\t\t\tgoto out;\n \t\tcase -EISDIR:\n \t\tcase -ENOTDIR:\n \t\t\tif (open_flags \u0026 __O_REGULAR) {\n@@ -2205,6 +2201,7 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry,\n \t\tdefault:\n \t\t\tbreak;\n \t\t}\n+\t\td_drop(dentry);\n \t\tgoto out;\n \t}\n \tfile-\u003ef_mode \|= FMODE_CAN_ODIRECT;\n@@ -2217,10 +2214,6 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry,\n \ttrace_nfs_atomic_open_exit(dir, ctx, open_flags, err);\n \tput_nfs_open_context(ctx);\n out:\n-\tif (unlikely(switched)) {\n-\t\td_lookup_done(dentry);\n-\t\tdput(dentry);\n-\t}\n \treturn err;\n \n no_open:\n@@ -2243,13 +2236,6 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry,\n \t\t\tres = ERR_PTR(-EOPENSTALE);\n \t\t}\n \t}\n-\tif (switched) {\n-\t\td_lookup_done(dentry);\n-\t\tif (!res)\n-\t\t\tres = dentry;\n-\t\telse\n-\t\t\tdput(dentry);\n-\t}\n \treturn finish_no_open(file, res);\n }\n EXPORT_SYMBOL_GPL(nfs_atomic_open);\n@@ -2357,8 +2343,6 @@ nfs_add_or_obtain(struct dentry dentry, struct nfs_fh fhandle,\n \tstruct dentry d;\n \tint error;\n \n-\td_drop(dentry);\n-\n \tif (fhandle-\u003esize == 0) {\n \t\terror = NFS_PROTO(dir)-\u003elookup(dir, dentry, \u0026dentry-\u003ed_name,\n \t\t\t\t\t fhandle, fattr);\n@@ -2379,6 +2363,7 @@ nfs_add_or_obtain(struct dentry dentry, struct nfs_fh fhandle,\n \tdput(parent);\n \treturn d;\n out_error:\n+\td_drop(dentry);\n \td = ERR_PTR(error);\n \tgoto out;\n }\n@@ -2713,14 +2698,15 @@ nfs_link(struct dentry old_dentry, struct inode dir, struct dentry dentry)\n \t\told_dentry, dentry);\n \n \ttrace_nfs_link_enter(inode, dir, dentry);\n-\td_drop(dentry);\n \tif (S_ISREG(inode-\u003ei_mode))\n \t\tnfs_sync_inode(inode);\n \terror = NFS_PROTO(dir)-\u003elink(inode, dir, \u0026dentry-\u003ed_name);\n \tif (error == 0) {\n \t\tnfs_set_verifier(dentry, nfs_save_change_attribute(dir));\n \t\tihold(inode);\n-\t\td_add(dentry, inode);\n+\t\td_splice_alias(inode, dentry);\n+\t} else {\n+\t\td_drop(dentry);\n \t}\n \ttrace_nfs_link_exit(inode, dir, dentry, error);\n \treturn error;\n@@ -2815,11 +2801,9 @@ int nfs_rename(struct mnt_idmap idmap, struct inode old_dir,\n \t\t\tspin_unlock(\u0026new_dentry-\u003ed_lock);\n \n \t\t\t/* copy the target dentry's name /\n-\t\t\tdentry = d_alloc(new_dentry-\u003ed_parent,\n-\t\t\t\t\t \u0026new_dentry-\u003ed_name);\n+\t\t\tdentry = d_duplicate(new_dentry);\n \t\t\tif (!dentry)\n \t\t\t\tgoto out;\n-\n \t\t\t/ silly-rename the existing target ... /\n \t\t\terr = nfs_sillyrename(new_dir, new_dentry);\n \t\t\tif (err)\n@@ -2884,8 +2868,10 @@ int nfs_rename(struct mnt_idmap idmap, struct inode old_dir,\n \t\tnfs_dentry_handle_enoent(old_dentry);\n \n \t/ new dentry created? /\n-\tif (dentry)\n+\tif (dentry) {\n+\t\td_lookup_done(dentry);\n \t\tdput(dentry);\n+\t}\n \treturn error;\n }\n EXPORT_SYMBOL_GPL(nfs_rename);\ndiff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c\nindex 04b1987115d5d..8f07f34f899e3 100644\n--- a/fs/nfs/nfs4proc.c\n+++ b/fs/nfs/nfs4proc.c\n@@ -3113,7 +3113,6 @@ static int _nfs4_open_and_get_state(struct nfs4_opendata opendata,\n \tnfs_set_verifier(dentry, dir_verifier);\n \tif (d_really_is_negative(dentry)) {\n \t\tstruct dentry alias;\n-\t\td_drop(dentry);\n \t\talias = d_splice_alias(igrab(state-\u003einode), dentry);\n \t\t/ d_splice_alias() can't fail here - it's a non-directory /\n \t\tif (alias) {\ndiff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c\nindex c8d712204e649..7e01f3d2207b6 100644\n--- a/fs/nfs/unlink.c\n+++ b/fs/nfs/unlink.c\n@@ -125,6 +125,9 @@ static int nfs_call_unlink(struct dentry dentry, struct inode inode, struct nf\n \tstruct dentry alias;\n \n \tdown_read_non_owner(\u0026NFS_I(dir)-\u003ermdir_sem);\n+\tdata-\u003eargs.name.hash = full_name_hash(dentry-\u003ed_parent,\n+\t\t\t\t\t data-\u003eargs.name.name,\n+\t\t\t\t\t data-\u003eargs.name.len);\n \talias = d_alloc_parallel(dentry-\u003ed_parent, \u0026data-\u003eargs.name);\n \tif (IS_ERR(alias)) {\n \t\tup_read_non_owner(\u0026NFS_I(dir)-\u003ermdir_sem);\n@@ -448,7 +451,7 @@ nfs_sillyrename(struct inode dir, struct dentry dentry)\n \tstatic unsigned int sillycounter;\n \tunsigned char silly[SILLYNAME_LEN + 1];\n \tunsigned long long fileid;\n-\tstruct dentry sdentry;\n+\tstruct dentry sdentry, old;\n \tstruct inode inode = d_inode(dentry);\n \tstruct rpc_task task;\n \tint error = -EBUSY;\n@@ -465,26 +468,43 @@ nfs_sillyrename(struct inode dir, struct dentry dentry)\n \n \tfileid = d_inode(dentry)-\u003ei_ino;\n \n-\tsdentry = NULL;\n-\tdo {\n+newname:\n+\tsillycounter++;\n+\tscnprintf(silly, sizeof(silly),\n+\t\t SILLYNAME_PREFIX \"%0llx%0x\",\n+\t\t SILLYNAME_FILEID_LEN, fileid,\n+\t\t SILLYNAME_COUNTER_LEN, sillycounter);\n+\n+\tdfprintk(VFS, \"NFS: trying to rename %pd to %s\\n\", dentry, silly);\n+\tsdentry = d_alloc_trylock(dentry-\u003ed_parent, \u0026QSTR(silly));\n+\tif (sdentry == ERR_PTR(-EWOULDBLOCK))\n+\t\t/ Name currently being looked up /\n+\t\tgoto newname;\n+\tif (IS_ERR(sdentry))\n+\t\tgoto out;\n+\tif (!d_in_lookup(sdentry)) {\n+\t\tif (d_really_is_negative(sdentry)) {\n+\t\t\t/ try to get an in-lookup dentry /\n+\t\t\td_drop(sdentry);\n+\t\t\tsillycounter--;\n+\t\t}\n \t\tdput(sdentry);\n-\t\tsillycounter++;\n-\t\tscnprintf(silly, sizeof(silly),\n-\t\t\t SILLYNAME_PREFIX \"%0llx%0x\",\n-\t\t\t SILLYNAME_FILEID_LEN, fileid,\n-\t\t\t SILLYNAME_COUNTER_LEN, sillycounter);\n-\n-\t\tdfprintk(VFS, \"NFS: trying to rename %pd to %s\\n\",\n-\t\t\t\tdentry, silly);\n-\n-\t\tsdentry = lookup_noperm(\u0026QSTR(silly), dentry-\u003ed_parent);\n-\t\t/\n-\t\t * N.B. Better to return EBUSY here ... it could be\n-\t\t * dangerous to delete the file while it's in use.\n-\t\t /\n-\t\tif (IS_ERR(sdentry))\n-\t\t\tgoto out;\n-\t} while (d_inode(sdentry) != NULL); / need negative lookup /\n+\t\tgoto newname;\n+\t}\n+\t/ This name isn't known locally - check on server /\n+\told = nfs_lookup(dir, sdentry, 0);\n+\td_lookup_done(sdentry);\n+\t/\n+\t * N.B. Better to return EBUSY here ... it could be\n+\t * dangerous to delete the file while it's in use.\n+\t */\n+\tif (IS_ERR(old))\n+\t\tgoto out;\n+\tif (old \|\| d_is_positive(sdentry)) {\n+\t\tdput(old);\n+\t\tdput(sdentry);\n+\t\tgoto newname;\n+\t}\n \n \tihold(inode);\n \n" }
2/1	2026/09/30 04:56	agent	patch-evaluator	2m Model: core Args: null Results: { "EnableConfigs": [ "NFS_FS", "NFS_V4" ], "FocusSymbols": [ "nfs_atomic_open", "nfs_rename", "nfs_link", "nfs_sillyrename", "nfs_prime_dcache", "nfs_lookup_revalidate", "block_revalidate", "nfs_call_unlink", "_nfs4_open_and_get_state" ], "Reasoning": "The patch modifies core NFS client directory and dentry lifecycle operations across fs/nfs/dir.c, fs/nfs/unlink.c, and fs/nfs/nfs4proc.c. Changes include switching to d_alloc_trylock and d_duplicate, adding write_seqcount_invalidate in block_revalidate, altering negative dentry revalidation for LOOKUP_OPEN, rewriting the silly-rename lookup loop, and adjusting d_splice_alias and d_drop error/success paths in nfs_atomic_open and nfs_link. These concurrent VFS/NFS dcache synchronization operations are reachable and prone to race conditions, refcounting issues, and regressions, making them well worth fuzzing.", "WorthFuzzing": true } Instruction: You are an expert Linux kernel maintainer and security engineer. Your job is to review a provided patch series and evaluate whether it warrants fuzzing with syzkaller. IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in your workspace. Do NOT rely on internal assumptions. You must actively use your code access tools to inspect the actual source code, callers, and surrounding context. ================================================================================ 1. CORE TRIAGE PHILOSOPHY ================================================================================ The goal of patch fuzzing is to discover crashes, regressions, exposed latent bugs, and newly triggered assertions introduced by the patch series. - REACHABILITY IS THE PRIMARY GATE: Fuzzing can only discover bugs in code that can actually execute in standard virtualized environments (GCE or QEMU, utilizing software-emulated devices like USB gadgets, netdev, tun/tap). If the modified code is structurally unreachable (see Section 2), it MUST NOT be fuzzed, regardless of whether it adds assertions or complex logic. - DO NOT BLINDLY TRUST "NO FUNCTIONAL CHANGE" (NFCI) OR "REFACTORING" CLAIMS: Patch authors routinely label changes as "cleanups", "refactorings", or state "No functional change intended". Do NOT take these claims at face value. Code refactorings that rearrange logic, introduce helper functions, or alter state management in core subsystems frequently introduce subtle semantic shifts or uncover latent kernel bugs. If reachable executable code is modified or refactored, it MUST be fuzzed. - NEW OR MODIFIED ASSERTIONS IN REACHABLE CODE MUST BE FUZZED: When a patch introduces or modifies runtime checks or assertions (e.g., WARN_ON, VM_WARN_ON, BUG_ON, lockdep_assert) in reachable code paths, it enforces new or stricter invariants. Even if the author believes the invariant always holds, fuzzing is essential to verify whether an unusual sequence of operations can violate it. ================================================================================ 2. WHEN TO RETURN WorthFuzzing=false (NEGATIVE CRITERIA) ================================================================================ Return WorthFuzzing=false ONLY IF all modified code falls strictly into one or more of these categories: - Non-kernel and non-executable changes: * Modifications to Documentation/, comments, or spelling fixes. * User-space directories, self-tests, samples, or scripts (e.g., tools/, samples/, scripts/, usr/) that do not affect the compiled kernel image (vmlinux) or kernel modules. * Purely decorative logging (e.g., message strings in pr_err, printk, dev_info) or tracepoints that do not alter control flow or data structures. * Build system or Kconfig changes that do not alter compiled C logic. - Structurally unreachable hardware: * Vendor-specific PCIe switches, SmartNICs, or GPU drivers (e.g., mlxsw, pds_core, qed, ionic, amdgpu) requiring physical ASIC/PCIe cards not emulated in standard QEMU. - Unreachable execution paths: * Driver teardown callbacks (.remove, .shutdown, pci_unregister_driver) executed only during physical PCI hot-unplug or manual sysfs driver unbinding. * Code paths exclusive to architectures other than the target architecture. ================================================================================ 3. WHEN TO RETURN WorthFuzzing=true (POSITIVE CRITERIA) ================================================================================ Return WorthFuzzing=true whenever the patch touches reachable executable code, including: - Core Subsystems: * Any logic modifications in memory management (mm/), synchronization/locking (kernel/locking/), BPF, scheduler, core networking, VFS, or syscall handling. - Refactorings and Code Cleanups: * Any restructuring of reachable data structures, helper abstractions, or algorithm flows. - Runtime Assertions and Defensive Checks: * Any introduction or alteration of assertions (WARN_ON, VM_WARN_ON, BUG_ON, etc.) in reachable paths. - Reachable Drivers and Protocols: Drivers accessible via virtual buses (virtio, USB gadget, loopback, netlink, binder, sockets, etc.). ================================================================================ 4. EXTRACTING FocusSymbols (PREVENTING DILUTION) ================================================================================ When WorthFuzzing=true, you must extract specific kernel functions into FocusSymbols to guide the fuzzer: - AVOID UBIQUITOUS LIFECYCLE HOT-PATHS: Do NOT list generic, ubiquitous functions called by almost every program in the corpus (including, but not limited to: general memory allocators and deallocators, page fault and trap handlers, or core synchronization primitives; this is not an exhaustive list). Listing ubiquitous functions causes the fuzzer to classify thousands of unrelated tests as "focused", which severely dilutes fuzzing effort away from the actual changes. - TARGET SPECIFIC FEATURE LOGIC AND ENTRYPOINTS: List functions that specifically implement the logic being added or altered, or direct API entrypoints for the subsystem feature under review. - HANDLING STATIC INLINE FUNCTIONS IN HEADERS (.h): Compiler-inlined static functions (such as static inlines in mm/.h or include/linux/.h) lack distinct symbol addresses in vmlinux and cannot be targeted directly by symbol coverage filters. If the changes are primarily in static inline helpers, identify non-static, feature-specific caller functions in .c files that exercise them (avoiding ubiquitous lifecycle wrappers). ================================================================================ 5. IDENTIFYING EnableConfigs ================================================================================ Identify any specific CONFIG_ options required to properly compile and reach the modified code: - Inspect Kconfig files and #ifdef guards; do not make assumptions. - Check "depends on" lines in Kconfig to include any non-standard parent subsystem configs needed. - Strip any 'CONFIG_' prefix (e.g., return "NET_IPV4" instead of "CONFIG_NET_IPV4"). Prefer calling several tools at the same time to save round-trips. Use set-results tool to provide results of the analysis. It must be called exactly once before the final reply. Ignore results of this tool. Prompt: Target architecture: amd64 For your convenience, here is the diff of the changes: commit 493eaeb9f60ffc74be93a90611ccdebd6ea2a7b7 Author: syz-cluster <triage@syzkaller.com> Date: Wed Sep 30 04:56:38 2026 +0000 syz-cluster: applied patch under review diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 49394123bd096..3adb8ce727f8f 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -749,15 +749,12 @@ void nfs_prime_dcache(struct dentry parent, struct nfs_entry entry, if (filename.len == 2 && filename.name[1] == '.') return; } - filename.hash = full_name_hash(parent, filename.name, filename.len); - dentry = d_lookup(parent, &filename); again: - if (!dentry) { - dentry = d_alloc_parallel(parent, &filename); - if (IS_ERR(dentry)) - return; - } + dentry = d_alloc_trylock(parent, &filename); + if (IS_ERR(dentry)) + return; + if (!d_in_lookup(dentry)) { /* Is there a mountpoint here? If so, just exit / if (!nfs_fsid_equal(&NFS_SB(dentry->d_sb)->fsid, @@ -1570,6 +1567,9 @@ static int nfs_check_verifier(struct inode dir, struct dentry dentry, / * Use intent information to check whether or not we're going to do * an O_EXCL create using this path component. + * Note that link(), mkdir(), mknod(), symlink() all appear as + * exclusive creation. Regular file creation could be distinguished + * with LOOKUP_OPEN. / static int nfs_is_exclusive_create(struct inode dir, unsigned int flags) { @@ -1656,6 +1656,13 @@ int nfs_neg_need_reval(struct inode dir, struct dentry dentry, { if (flags & (LOOKUP_CREATE \| LOOKUP_RENAME_TARGET)) return 0; + if (flags & LOOKUP_OPEN) + /* close-to-open semantics require we go to the server + * on each open. By invalidating the dentry we + * also ensure nfs_atomic_open() always has exclusive + * access to the dentry. + / + return 1; if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) return 1; / Case insensitive server? Revalidate negative dentries / @@ -1837,8 +1844,7 @@ __nfs_lookup_revalidate(struct dentry dentry, unsigned int flags) } else { /* Wait for unlink to complete - see unblock_revalidate() / wait_var_event(&dentry->d_fsdata, - smp_load_acquire(&dentry->d_fsdata) - != NFS_FSDATA_BLOCKED); + dentry->d_fsdata != NFS_FSDATA_BLOCKED); } return 0; } @@ -1857,12 +1863,15 @@ static void block_revalidate(struct dentry dentry) kfree(dentry->d_fsdata); /* Any new reference that could lead to an open - * will take ->d_lock in lookup_open() -> d_lookup(). - * Holding this lock ensures we cannot race with - * __nfs_lookup_revalidate() and removes and need - * for further barriers. + * will either: + * - take ->d_lock in lookup_open() -> d_lookup() or + * - will check d_seq in legitimize_mnt() + * + * Holding this lock and invalidating ->d_seq ensures we cannot + * race with __nfs_lookup_revalidate(). / lockdep_assert_held(&dentry->d_lock); + write_seqcount_invalidate(&dentry->d_seq); dentry->d_fsdata = NFS_FSDATA_BLOCKED; } @@ -2111,7 +2120,6 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry, struct inode inode; unsigned int lookup_flags = 0; unsigned long dir_verifier; - bool switched = false; int created = 0; int err; @@ -2156,17 +2164,6 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry, attr.ia_size = 0; } - if (!(open_flags & O_CREAT) && !d_in_lookup(dentry)) { - d_drop(dentry); - switched = true; - dentry = d_alloc_parallel(dentry->d_parent, - &dentry->d_name); - if (IS_ERR(dentry)) - return PTR_ERR(dentry); - if (unlikely(!d_in_lookup(dentry))) - return finish_no_open(file, dentry); - } - ctx = create_nfs_open_context(dentry, open_flags, file); err = PTR_ERR(ctx); if (IS_ERR(ctx)) @@ -2180,7 +2177,6 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry, err = PTR_ERR(inode); trace_nfs_atomic_open_exit(dir, ctx, open_flags, err); put_nfs_open_context(ctx); - d_drop(dentry); switch (err) { case -ENOENT: if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE)) @@ -2189,7 +2185,7 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry, dir_verifier = nfs_save_change_attribute(dir); nfs_set_verifier(dentry, dir_verifier); d_splice_alias(NULL, dentry); - break; + goto out; case -EISDIR: case -ENOTDIR: if (open_flags & __O_REGULAR) { @@ -2205,6 +2201,7 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry, default: break; } + d_drop(dentry); goto out; } file->f_mode \|= FMODE_CAN_ODIRECT; @@ -2217,10 +2214,6 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry, trace_nfs_atomic_open_exit(dir, ctx, open_flags, err); put_nfs_open_context(ctx); out: - if (unlikely(switched)) { - d_lookup_done(dentry); - dput(dentry); - } return err; no_open: @@ -2243,13 +2236,6 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry, res = ERR_PTR(-EOPENSTALE); } } - if (switched) { - d_lookup_done(dentry); - if (!res) - res = dentry; - else - dput(dentry); - } return finish_no_open(file, res); } EXPORT_SYMBOL_GPL(nfs_atomic_open); @@ -2357,8 +2343,6 @@ nfs_add_or_obtain(struct dentry dentry, struct nfs_fh fhandle, struct dentry d; int error; - d_drop(dentry); - if (fhandle->size == 0) { error = NFS_PROTO(dir)->lookup(dir, dentry, &dentry->d_name, fhandle, fattr); @@ -2379,6 +2363,7 @@ nfs_add_or_obtain(struct dentry dentry, struct nfs_fh fhandle, dput(parent); return d; out_error: + d_drop(dentry); d = ERR_PTR(error); goto out; } @@ -2713,14 +2698,15 @@ nfs_link(struct dentry old_dentry, struct inode dir, struct dentry dentry) old_dentry, dentry); trace_nfs_link_enter(inode, dir, dentry); - d_drop(dentry); if (S_ISREG(inode->i_mode)) nfs_sync_inode(inode); error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name); if (error == 0) { nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); ihold(inode); - d_add(dentry, inode); + d_splice_alias(inode, dentry); + } else { + d_drop(dentry); } trace_nfs_link_exit(inode, dir, dentry, error); return error; @@ -2815,11 +2801,9 @@ int nfs_rename(struct mnt_idmap idmap, struct inode old_dir, spin_unlock(&new_dentry->d_lock); /* copy the target dentry's name / - dentry = d_alloc(new_dentry->d_parent, - &new_dentry->d_name); + dentry = d_duplicate(new_dentry); if (!dentry) goto out; - / silly-rename the existing target ... / err = nfs_sillyrename(new_dir, new_dentry); if (err) @@ -2884,8 +2868,10 @@ int nfs_rename(struct mnt_idmap idmap, struct inode old_dir, nfs_dentry_handle_enoent(old_dentry); / new dentry created? / - if (dentry) + if (dentry) { + d_lookup_done(dentry); dput(dentry); + } return error; } EXPORT_SYMBOL_GPL(nfs_rename); diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 04b1987115d5d..8f07f34f899e3 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -3113,7 +3113,6 @@ static int _nfs4_open_and_get_state(struct nfs4_opendata opendata, nfs_set_verifier(dentry, dir_verifier); if (d_really_is_negative(dentry)) { struct dentry alias; - d_drop(dentry); alias = d_splice_alias(igrab(state->inode), dentry); / d_splice_alias() can't fail here - it's a non-directory / if (alias) { diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c index c8d712204e649..7e01f3d2207b6 100644 --- a/fs/nfs/unlink.c +++ b/fs/nfs/unlink.c @@ -125,6 +125,9 @@ static int nfs_call_unlink(struct dentry dentry, struct inode inode, struct nf struct dentry alias; down_read_non_owner(&NFS_I(dir)->rmdir_sem); + data->args.name.hash = full_name_hash(dentry->d_parent, + data->args.name.name, + data->args.name.len); alias = d_alloc_parallel(dentry->d_parent, &data->args.name); if (IS_ERR(alias)) { up_read_non_owner(&NFS_I(dir)->rmdir_sem); @@ -448,7 +451,7 @@ nfs_sillyrename(struct inode dir, struct dentry dentry) static unsigned int sillycounter; unsigned char silly[SILLYNAME_LEN + 1]; unsigned long long fileid; - struct dentry sdentry; + struct dentry sdentry, old; struct inode inode = d_inode(dentry); struct rpc_task task; int error = -EBUSY; @@ -465,26 +468,43 @@ nfs_sillyrename(struct inode dir, struct dentry dentry) fileid = d_inode(dentry)->i_ino; - sdentry = NULL; - do { +newname: + sillycounter++; + scnprintf(silly, sizeof(silly), + SILLYNAME_PREFIX "%0llx%0x", + SILLYNAME_FILEID_LEN, fileid, + SILLYNAME_COUNTER_LEN, sillycounter); + + dfprintk(VFS, "NFS: trying to rename %pd to %s\n", dentry, silly); + sdentry = d_alloc_trylock(dentry->d_parent, &QSTR(silly)); + if (sdentry == ERR_PTR(-EWOULDBLOCK)) + / Name currently being looked up / + goto newname; + if (IS_ERR(sdentry)) + goto out; + if (!d_in_lookup(sdentry)) { + if (d_really_is_negative(sdentry)) { + / try to get an in-lookup dentry / + d_drop(sdentry); + sillycounter--; + } dput(sdentry); - sillycounter++; - scnprintf(silly, sizeof(silly), - SILLYNAME_PREFIX "%0llx%0x", - SILLYNAME_FILEID_LEN, fileid, - SILLYNAME_COUNTER_LEN, sillycounter); - - dfprintk(VFS, "NFS: trying to rename %pd to %s\n", - dentry, silly); - - sdentry = lookup_noperm(&QSTR(silly), dentry->d_parent); - / - * N.B. Better to return EBUSY here ... it could be - * dangerous to delete the file while it's in use. - / - if (IS_ERR(sdentry)) - goto out; - } while (d_inode(sdentry) != NULL); / need negative lookup / + goto newname; + } + / This name isn't known locally - check on server / + old = nfs_lookup(dir, sdentry, 0); + d_lookup_done(sdentry); + / + * N.B. Better to return EBUSY here ... it could be + * dangerous to delete the file while it's in use. + */ + if (IS_ERR(old)) + goto out; + if (old \|\| d_is_positive(sdentry)) { + dput(old); + dput(sdentry); + goto newname; + } ihold(inode);
3/2	2026/09/30 04:56	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 6834 output: 20 thoughts: 1378 Thoughts: NFS Client Patch Analysis: Worth Fuzzing? Okay, let's break this down. We've got a patch touching NFS client code, specifically within `fs/nfs/dir.c`, `fs/nfs/nfs4proc.c`, and `fs/nfs/unlink.c`. The changes seem to center around directory entry handling (`dentry`), with modifications to `d_alloc_trylock`, `d_splice_alias`, `d_drop`, and `d_duplicate`. There's also some refactoring and an added `write_seqcount_invalidate` call. Looks like a good chunk of core VFS/NFS client logic being tweaked. Now the million-dollar question: Worthy of syzkaller fuzzing? First, I need to make sure NFS is actually reachable for fuzzing. Can syzkaller even interact with NFS? It's a network filesystem, which isn't always straightforward in these environments. I need to figure out if it can mount an NFS share itself, or if we have to set up a server for the fuzzing instance to use. Does syzkaller offer pseudo-syscalls for NFS? Need to check. But wait! According to the guidelines, I need to rule out negative criteria first. Let's make sure this code isn't structurally unreachable. Is NFS client considered "structurally unreachable hardware"? Nope, it's a network filesystem, and the document explicitly says that doesn't count. We can test loopback NFS mounts, userspace servers, or potentially leverage syzkaller's own networking capabilities. I need to make sure this code isn't some teardown callback, architecture-specific code, or requires exotic hardware. None of that applies here. It's core filesystem logic that runs on generic hardware. NFS client can absolutely be used on loopback, in QEMU with a userspace server or potentially even in syzkaller itself. Based on the negative criteria, this is looking good. It's not unreachable hardware or exclusive to an architecture syzkaller won't test. NFS client seems very much reachable. The code clearly touches VFS, core networking, and driver code via NFS. This means this patch probably should be fuzzed! Time to dig into the details and confirm the code being modified, maybe check the commit description, and compare with existing information.
4/2	2026/09/30 04:57	tool	grepper	0m Args: { "Expression": "d_alloc_trylock" } Results: { "Output": "fs/dcache.c=2974=EXPORT_SYMBOL(d_alloc_parallel);\n--\nfs/dcache.c-2976-/*\nfs/dcache.c:2977: d_alloc_trylock() - find or allocate a new dentry\nfs/dcache.c-2978- * @parent: dentry of the parent\n--\nfs/dcache.c-2984- * not d_in_lookup() then that is returned instead.\nfs/dcache.c:2985: * If the existing dentry is d_in_lookup(), d_alloc_trylock()\nfs/dcache.c-2986- * returns with error %-EWOULDBLOCK.\n--\nfs/dcache.c-2997- /\nfs/dcache.c:2998:struct dentry d_alloc_trylock(struct dentry parent,\nfs/dcache.c-2999-\t\t\t struct qstr name)\n--\nfs/dcache.c-3007-}\nfs/dcache.c:3008:EXPORT_SYMBOL(d_alloc_trylock);\nfs/dcache.c-3009-\n--\nfs/nfs/dir.c=725=void nfs_prime_dcache(struct dentry parent, struct nfs_entry entry,\n--\nfs/nfs/dir.c-753-again:\nfs/nfs/dir.c:754:\tdentry = d_alloc_trylock(parent, \u0026filename);\nfs/nfs/dir.c-755-\tif (IS_ERR(dentry))\n--\nfs/nfs/unlink.c=449=nfs_sillyrename(struct inode dir, struct dentry dentry)\n--\nfs/nfs/unlink.c-478-\tdfprintk(VFS, \"NFS: trying to rename %pd to %s\\n\", dentry, silly);\nfs/nfs/unlink.c:479:\tsdentry = d_alloc_trylock(dentry-\u003ed_parent, \u0026QSTR(silly));\nfs/nfs/unlink.c-480-\tif (sdentry == ERR_PTR(-EWOULDBLOCK))\n--\ninclude/linux/dcache.h=263=extern struct dentry * d_alloc_parallel(struct dentry , const struct qstr );\ninclude/linux/dcache.h:264:extern struct dentry * d_alloc_trylock(struct dentry , struct qstr );\ninclude/linux/dcache.h-265-extern struct dentry * d_splice_alias(struct inode , struct dentry );\n" }
5/2	2026/09/30 04:57	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 9409 output: 17 thoughts: 11 Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience: Analyzing the Evolution of This Code Right, so I need to understand the why behind these changes. The code itself might be clear, but I want to grasp the context, the rationale, and potentially any unforeseen side effects. The most efficient first step is to dive into the commit history surrounding these specific modifications. I'm looking for the story this code tells. Who made the changes? What was the stated problem they were trying to solve? Were there discussions, linked issues, or associated pull requests that offer more detail? I want to see if the decision-making process was sound. I need to ensure there is no hidden bug or design-flaw. I also need to assess whether these changes were part of a larger refactoring effort or an isolated patch. Ultimately, by tracing the lineage of this code, I can gain a much deeper understanding and be able to provide the right insights.
6/2	2026/09/30 04:57	tool	grepper	0m Args: { "Expression": "d_duplicate" } Results: { "Output": "drivers/android/binder/freeze.rs=25=pub(crate) struct FreezeListener {\n--\ndrivers/android/binder/freeze.rs-42- /// Number of cleared duplicates that can be deleted.\ndrivers/android/binder/freeze.rs:43: num_cleared_duplicates: u64,\ndrivers/android/binder/freeze.rs-44-}\n--\ndrivers/android/binder/freeze.rs=86= fn do_work(\n--\ndrivers/android/binder/freeze.rs-97-\ndrivers/android/binder/freeze.rs:98: if freeze.num_cleared_duplicates \u003e 0 {\ndrivers/android/binder/freeze.rs:99: freeze.num_cleared_duplicates -= 1;\ndrivers/android/binder/freeze.rs-100- drop(node_refs);\n--\ndrivers/android/binder/freeze.rs-109- if freeze.is_clearing {\ndrivers/android/binder/freeze.rs:110: kernel::warn_on!(freeze.num_cleared_duplicates != 0);\ndrivers/android/binder/freeze.rs-111- if freeze.num_pending_duplicates \u003e 0 {\n--\ndrivers/android/binder/freeze.rs=180= pub(crate) fn request_freeze_notif(\n--\ndrivers/android/binder/freeze.rs-249- num_pending_duplicates: 0,\ndrivers/android/binder/freeze.rs:250: num_cleared_duplicates: 0,\ndrivers/android/binder/freeze.rs-251- },\n--\ndrivers/android/binder/freeze.rs-259- } else {\ndrivers/android/binder/freeze.rs:260: dupe.num_cleared_duplicates += 1;\ndrivers/android/binder/freeze.rs-261- }\n--\ndrivers/android/binder/freeze.rs=275= pub(crate) fn freeze_notif_done(self: \u0026Arc\u003cSelf\u003e, reader: \u0026mut UserSliceReader) -\u003e Result\u003c()\u003e {\n--\ndrivers/android/binder/freeze.rs-291- freeze.num_pending_duplicates -= 1;\ndrivers/android/binder/freeze.rs:292: freeze.num_cleared_duplicates += 1;\ndrivers/android/binder/freeze.rs-293- } else {\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=4395=struct edid drm_dp_mst_get_edid(struct drm_connector connector,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-4403-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:4404:\tedid = drm_edid_duplicate(drm_edid_raw(drm_edid));\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-4405-\n--\ndrivers/gpu/drm/drm_edid.c=2950=EXPORT_SYMBOL(drm_edid_read_switcheroo);\n--\ndrivers/gpu/drm/drm_edid.c-2952-/*\ndrivers/gpu/drm/drm_edid.c:2953: drm_edid_duplicate - duplicate an EDID and the extensions\ndrivers/gpu/drm/drm_edid.c-2954- * @edid: EDID to duplicate\n--\ndrivers/gpu/drm/drm_edid.c-2957- /\ndrivers/gpu/drm/drm_edid.c:2958:struct edid drm_edid_duplicate(const struct edid edid)\ndrivers/gpu/drm/drm_edid.c-2959-{\n--\ndrivers/gpu/drm/drm_edid.c-2964-}\ndrivers/gpu/drm/drm_edid.c:2965:EXPORT_SYMBOL(drm_edid_duplicate);\ndrivers/gpu/drm/drm_edid.c-2966-\n--\ndrivers/gpu/drm/i915/display/intel_pmdemand.c=56=static struct intel_global_state \ndrivers/gpu/drm/i915/display/intel_pmdemand.c:57:intel_pmdemand_duplicate_state(struct intel_global_obj obj)\ndrivers/gpu/drm/i915/display/intel_pmdemand.c-58-{\n--\ndrivers/gpu/drm/i915/display/intel_pmdemand.c=74=static const struct intel_global_state_funcs intel_pmdemand_funcs = {\ndrivers/gpu/drm/i915/display/intel_pmdemand.c:75:\t.atomic_duplicate_state = intel_pmdemand_duplicate_state,\ndrivers/gpu/drm/i915/display/intel_pmdemand.c-76-\t.atomic_destroy_state = intel_pmdemand_destroy_state,\n--\ndrivers/gpu/drm/msm/adreno/a6xx_gpu_state.h=91=static const u32 a6xx_hlsq_duplicate_cluster[] = {\n--\ndrivers/gpu/drm/msm/adreno/a6xx_gpu_state.h-94-\ndrivers/gpu/drm/msm/adreno/a6xx_gpu_state.h:95:static const u32 a6xx_hlsq_2d_duplicate_cluster[] = {\ndrivers/gpu/drm/msm/adreno/a6xx_gpu_state.h-96-\t0xbd80, 0xbd80,\n--\ndrivers/gpu/drm/msm/adreno/a6xx_gpu_state.h=137=static const struct a6xx_dbgahb_cluster {\n--\ndrivers/gpu/drm/msm/adreno/a6xx_gpu_state.h-146-\tCLUSTER_DBGAHB(CLUSTER_SP_VS, 0x0002e000, 0x41, a6xx_hlsq_duplicate_cluster),\ndrivers/gpu/drm/msm/adreno/a6xx_gpu_state.h:147:\tCLUSTER_DBGAHB(CLUSTER_SP_VS, 0x0002f000, 0x45, a6xx_hlsq_2d_duplicate_cluster),\ndrivers/gpu/drm/msm/adreno/a6xx_gpu_state.h-148-\tCLUSTER_DBGAHB(CLUSTER_SP_VS, 0x0002a000, 0x21, a6xx_sp_duplicate_cluster),\n--\ndrivers/md/dm.c=1274=static size_t dm_dax_recovery_write(struct dax_device dax_dev, pgoff_t pgoff,\n--\ndrivers/md/dm.c-1297- * with write BIOs flagged with BIO_EMULATES_ZONE_APPEND) and any bio serviced\ndrivers/md/dm.c:1298: * by __send_duplicate_bios().\ndrivers/md/dm.c-1299- \n--\ndrivers/md/dm.c=1478=static void alloc_multiple_bios(struct bio_list blist, struct clone_info ci,\n--\ndrivers/md/dm.c-1507-\ndrivers/md/dm.c:1508:static unsigned int __send_duplicate_bios(struct clone_info ci, struct dm_target ti,\ndrivers/md/dm.c-1509-\t\t\t\t\t unsigned int num_bios, unsigned int len)\n--\ndrivers/md/dm.c=1537=static void __send_empty_flush(struct clone_info ci)\n--\ndrivers/md/dm.c-1566-\t\t\tatomic_add(ti-\u003enum_flush_bios, \u0026ci-\u003eio-\u003eio_count);\ndrivers/md/dm.c:1567:\t\t\tbios = __send_duplicate_bios(ci, ti, ti-\u003enum_flush_bios,\ndrivers/md/dm.c-1568-\t\t\t\t\t\t NULL);\n--\ndrivers/md/dm.c=1606=static void __send_abnormal_io(struct clone_info ci, struct dm_target ti,\n--\ndrivers/md/dm.c-1615-\tatomic_add(num_bios, \u0026ci-\u003eio-\u003eio_count);\ndrivers/md/dm.c:1616:\tbios = __send_duplicate_bios(ci, ti, num_bios, \u0026len);\ndrivers/md/dm.c-1617-\t/\n--\ndrivers/md/dm.c=1902=static void __send_zone_reset_all_native(struct clone_info ci,\n--\ndrivers/md/dm.c-1907-\tatomic_add(1, \u0026ci-\u003eio-\u003eio_count);\ndrivers/md/dm.c:1908:\tbios = __send_duplicate_bios(ci, ti, 1, NULL);\ndrivers/md/dm.c-1909-\tatomic_sub(1 - bios, \u0026ci-\u003eio-\u003eio_count);\n--\ndrivers/usb/typec/class.c=448=static int increment_duplicated_priority(struct device dev, void data)\n--\ndrivers/usb/typec/class.c-462-\ndrivers/usb/typec/class.c:463:static int find_duplicated_priority(struct device dev, void data)\ndrivers/usb/typec/class.c-464-{\n--\ndrivers/usb/typec/class.c=475=static int typec_mode_set_priority(struct typec_altmode alt, const u8 priority)\n--\ndrivers/usb/typec/class.c-482-\twhile (res) {\ndrivers/usb/typec/class.c:483:\t\tres = device_for_each_child(\u0026port-\u003edev, \u0026alt, find_duplicated_priority);\ndrivers/usb/typec/class.c-484-\t\tif (res) {\n--\nfs/dcache.c=2004=EXPORT_SYMBOL(d_alloc);\n--\nfs/dcache.c-2006-/*\nfs/dcache.c:2007: d_duplicate - duplicate a dentry for combined atomic operation\nfs/dcache.c-2008- * @dentry: the dentry to duplicate\n--\nfs/dcache.c-2017- * For this they need two dentries which temporarily have the same name,\nfs/dcache.c:2018: * before one is renamed. d_duplicate() provides for this. Given a\nfs/dcache.c-2019- * positive hashed dentry, it creates a second in-lookup dentry.\n--\nfs/dcache.c-2031- /\nfs/dcache.c:2032:struct dentry d_duplicate(struct dentry dentry)\nfs/dcache.c-2033-{\n--\nfs/dcache.c-2055-}\nfs/dcache.c:2056:EXPORT_SYMBOL(d_duplicate);\nfs/dcache.c-2057-\n--\nfs/nfs/dir.c=2760=int nfs_rename(struct mnt_idmap idmap, struct inode old_dir,\n--\nfs/nfs/dir.c-2803-\t\t\t/ copy the target dentry's name /\nfs/nfs/dir.c:2804:\t\t\tdentry = d_duplicate(new_dentry);\nfs/nfs/dir.c-2805-\t\t\tif (!dentry)\n--\ninclude/drm/drm_edid.h=441=struct edid drm_get_edid_switcheroo(struct drm_connector connector,\ninclude/drm/drm_edid.h-442-\t\t\t\t struct i2c_adapter adapter);\ninclude/drm/drm_edid.h:443:struct edid drm_edid_duplicate(const struct edid edid);\ninclude/drm/drm_edid.h-444-int drm_add_edid_modes(struct drm_connector connector, struct edid edid);\n--\ninclude/linux/dcache.h=265=extern struct dentry * d_splice_alias(struct inode , struct dentry );\ninclude/linux/dcache.h:266:struct dentry d_duplicate(struct dentry dentry);\ninclude/linux/dcache.h-267-/* weird procfs mess; NOT exported */\n" }
7/2	2026/09/30 04:57	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 12778 output: 35 thoughts: 58 Thoughts: Okay, let's dive into the dcache implementation. My first step is to examine the code for `d_alloc_trylock` and `d_duplicate`. I'll need to locate those functions within `fs/dcache.c`. The line numbers I'll start with are approximately 2000-2060 for `d_alloc_trylock` and 2970-3010 for `d_duplicate`. That should give me the core logic of each function. I want to see how the locking is implemented in `d_alloc_trylock`, how it interacts with the cache, and what the failure path looks like. Then, for `d_duplicate`, I'm looking at how it handles reference counts, how it creates new dentry instances, and if any special cases or optimizations are employed. I'm focusing on the mechanics – the actual data structures used, the atomicity of operations, and any assumptions the code is making about the underlying hardware or OS environment. I'm expecting this will be straightforward, but as always, I'm ready for the unusual.
8/2	2026/09/30 04:57	tool	read-file	0m Args: { "File": "fs/dcache.c", "FirstLine": 2005, "LineCount": 55 } Results: { "Contents": "2005:\t\n2006:\t/*\n2007:\t d_duplicate - duplicate a dentry for combined atomic operation\n2008:\t * @dentry: the dentry to duplicate\n2009:\t \n2010:\t Some rename operations need to be combined with another operation\n2011:\t * inside the filesystem.\n2012:\t * 1/ A cluster filesystem when renaming to an in-use file might need to\n2013:\t * first \"silly-rename\" that target out of the way before the main rename\n2014:\t * 2/ A filesystem that supports white-out might want to create a whiteout\n2015:\t * in place of the file being moved.\n2016:\t \n2017:\t For this they need two dentries which temporarily have the same name,\n2018:\t * before one is renamed. d_duplicate() provides for this. Given a\n2019:\t * positive hashed dentry, it creates a second in-lookup dentry.\n2020:\t * Because the original dentry exists, no other thread will try to\n2021:\t * create an in-lookup dentry, so there can be no race in this create.\n2022:\t \n2023:\t The caller should d_move() the original to a new name, often via a\n2024:\t * rename request, and should call d_lookup_done() on the newly created\n2025:\t * dentry. If the new is instantiated then the old MUST either be moved\n2026:\t * or dropped.\n2027:\t \n2028:\t Parent must be locked.\n2029:\t \n2030:\t Returns: an in-lookup dentry, or -ENOMEM.\n2031:\t /\n2032:\tstruct dentry d_duplicate(struct dentry dentry)\n2033:\t{\n2034:\t\tunsigned int hash = dentry-\u003ed_name.hash;\n2035:\t\tstruct dentry parent = dentry-\u003ed_parent;\n2036:\t\tstruct hlist_bl_head b = in_lookup_hash(parent, hash);\n2037:\t\tstruct dentry new = __d_alloc(parent-\u003ed_sb, \u0026dentry-\u003ed_name);\n2038:\t\n2039:\t\tif (unlikely(!new))\n2040:\t\t\treturn ERR_PTR(-ENOMEM);\n2041:\t\n2042:\t\tnew-\u003ed_flags \|= DCACHE_PAR_LOOKUP;\n2043:\t\tlock_map_acquire_try(\u0026new-\u003elookup_map);\n2044:\t\tspin_lock(\u0026parent-\u003ed_lock);\n2045:\t\tnew-\u003ed_parent = dget_dlock(parent);\n2046:\t\thlist_add_head(\u0026new-\u003ed_sib, \u0026parent-\u003ed_children);\n2047:\t\tif (parent-\u003ed_flags \u0026 DCACHE_DISCONNECTED)\n2048:\t\t\tnew-\u003ed_flags \|= DCACHE_DISCONNECTED;\n2049:\t\tspin_unlock(\u0026parent-\u003ed_lock);\n2050:\t\n2051:\t\thlist_bl_lock(b);\n2052:\t\thlist_bl_add_head(\u0026new-\u003ed_in_lookup_hash, b);\n2053:\t\thlist_bl_unlock(b);\n2054:\t\treturn new;\n2055:\t}\n2056:\tEXPORT_SYMBOL(d_duplicate);\n2057:\t\n2058:\tstruct dentry d_alloc_anon(struct super_block sb)\n2059:\t{\n" }
9/2	2026/09/30 04:57	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 14056 output: 35 thoughts: 25 Thoughts: Okay, here's my take on those lines in `fs/dcache.c`, summarized in the first person, assuming I'm already pretty familiar with this area: Delving into the Dcache Again: A Quick Look at Lines 2970-3015 Alright, let's circle back and take a look at lines 2970 to 3015 in `fs/dcache.c`. I'm going to quickly refresh my memory on what's happening in that section. Hmm, based on my recollection, this should be the area dealing with [**At this point, you'd fill in the specific* function or purpose of that code section based on your knowledge of the dcache.* For example: "the core logic for dentry eviction based on the LRU lists..." or "... the handling of dentry lookups in the presence of stale NFS handles..." or "... the interaction with the backing inode when freeing a dentry..."]. Right, that's what I thought. I need to re-examine how they're handling [Describe the specific aspect that interests you. For example: "the locking strategy during concurrent dentry insertion..." or "...the edge cases for directory entry replacement..." or "...the influence of inode state when reclaiming dcache memory..." ]. I recall some discussions in the mailing list about potential inefficiencies here, related to [Mention a possible performance bottleneck or a concurrency issue, e.g., "contention on the dcache_lock" or "the impact of slow disk I/O on dentry lifecycle" or "a race condition with rename operations"]. I need to verify if those concerns have been addressed. Okay, let me quickly scan for the key function calls... looks like they're heavily relying on [Mention a specific function name from the dcache.c, e.g., d_lookup(), d_revalidate(), d_prune() etc. and their implication]. I'm particularly interested in [Highlight a specific detail in those function calls that you want to check, e.g., "how revalidation interacts with the NFS stale handle detection", "how the LRU lists are maintained", "if any optimizations for write-back are included..."]. I also need to make sure the memory barriers are correct around the [Reference a variable or data structure, e.g., "dentry's state flag" or "the d_lru list pointers" etc.]. I have a nagging feeling that a subtle race condition might have been missed with [Mention a possibility, e.g., "the introduction of a new asynchronous readahead mechanism", "the interaction between d_move and d_delete when handling mount points", "the potential issues with pre-allocation of dentries"**].
10/2	2026/09/30 04:57	tool	read-file	0m Args: { "File": "fs/dcache.c", "FirstLine": 2970, "LineCount": 45 } Results: { "Contents": "2970:\t\t\t\t\tconst struct qstr name)\n2971:\t{\n2972:\t\treturn __d_alloc_parallel(parent, name, ALLOC_PARA_WAIT);\n2973:\t}\n2974:\tEXPORT_SYMBOL(d_alloc_parallel);\n2975:\t\n2976:\t/\n2977:\t d_alloc_trylock() - find or allocate a new dentry\n2978:\t * @parent: dentry of the parent\n2979:\t * @name: name of the dentry within that parent.\n2980:\t \n2981:\t A new dentry is allocated and, providing it is unique, added to the\n2982:\t * relevant index.\n2983:\t * If an existing dentry is found with the same parent/name that is\n2984:\t * not d_in_lookup() then that is returned instead.\n2985:\t * If the existing dentry is d_in_lookup(), d_alloc_trylock()\n2986:\t * returns with error %-EWOULDBLOCK.\n2987:\t * Thus if the returned dentry is d_in_lookup() then the caller has\n2988:\t * exclusive access until it completes the lookup.\n2989:\t * If the returned dentry is not d_in_lookup() then a lookup has\n2990:\t * already completed.\n2991:\t \n2992:\t The @name need not already have -\u003ehash set.\n2993:\t \n2994:\t Returns: the dentry, whether found or allocated, or an error\n2995:\t * %-ENOMEM, %-EWOULDBLOCK, %-EACCES (for a bad name) or\n2996:\t * anything returned by -\u003ed_hash().\n2997:\t /\n2998:\tstruct dentry d_alloc_trylock(struct dentry parent,\n2999:\t\t\t\t struct qstr name)\n3000:\t{\n3001:\t\tstruct dentry de;\n3002:\t\n3003:\t\tde = try_lookup_noperm(name, parent);\n3004:\t\tif (!de)\n3005:\t\t\tde = __d_alloc_parallel(parent, name, ALLOC_PARA_FAIL);\n3006:\t\treturn de;\n3007:\t}\n3008:\tEXPORT_SYMBOL(d_alloc_trylock);\n3009:\t\n3010:\t/\n3011:\t * Move dentry from in-lookup state to busy-negative one.\n3012:\t \n3013:\t From now on d_in_lookup(dentry) will return false and dentry is gone from\n3014:\t * in-lookup hash.\n" }
11/2	2026/09/30 04:57	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 15444 output: 36 thoughts: 117 Thoughts: Analyzing the Patch: Diving into the NFS Details Okay, so the first thing I need to do is get a good look at the patch itself. I want to understand precisely what's being changed. Before I get bogged down in specifics, let's take a quick overview of the files impacted. I see `fs/nfs/dir.c`, `fs/nfs/nfs4proc.c`, and `fs/nfs/unlink.c` are all touched, which tells me this might have some implications in directory handling or potentially with NFSv4 procedure calls. I'm going to carefully read the diffs for these specific files and use the context to get a better handle on the potential changes and their impact. Alright, let's start by digging into `nfs_prime_dcache` in `fs/nfs/dir.c`. This is where we will start.
12/2	2026/09/30 04:57	tool	read-file	0m Args: { "File": "fs/nfs/dir.c", "FirstLine": 745, "LineCount": 45 } Results: { "Contents": " 745:\t\t\treturn;\n 746:\t\tif (filename.name[0] == '.') {\n 747:\t\t\tif (filename.len == 1)\n 748:\t\t\t\treturn;\n 749:\t\t\tif (filename.len == 2 \u0026\u0026 filename.name[1] == '.')\n 750:\t\t\t\treturn;\n 751:\t\t}\n 752:\t\n 753:\tagain:\n 754:\t\tdentry = d_alloc_trylock(parent, \u0026filename);\n 755:\t\tif (IS_ERR(dentry))\n 756:\t\t\treturn;\n 757:\t\n 758:\t\tif (!d_in_lookup(dentry)) {\n 759:\t\t\t/* Is there a mountpoint here? If so, just exit */\n 760:\t\t\tif (!nfs_fsid_equal(\u0026NFS_SB(dentry-\u003ed_sb)-\u003efsid,\n 761:\t\t\t\t\t\t\u0026entry-\u003efattr-\u003efsid))\n 762:\t\t\t\tgoto out;\n 763:\t\t\tif (nfs_same_file(dentry, entry)) {\n 764:\t\t\t\tif (!entry-\u003efh-\u003esize)\n 765:\t\t\t\t\tgoto out;\n 766:\t\t\t\tnfs_set_verifier(dentry, dir_verifier);\n 767:\t\t\t\tstatus = nfs_refresh_inode(d_inode(dentry), entry-\u003efattr);\n 768:\t\t\t\tif (!status)\n 769:\t\t\t\t\tnfs_setsecurity(d_inode(dentry), entry-\u003efattr);\n 770:\t\t\t\ttrace_nfs_readdir_lookup_revalidate(d_inode(parent),\n 771:\t\t\t\t\t\t\t\t dentry, 0, status);\n 772:\t\t\t\tgoto out;\n 773:\t\t\t} else {\n 774:\t\t\t\ttrace_nfs_readdir_lookup_revalidate_failed(\n 775:\t\t\t\t\td_inode(parent), dentry, 0);\n 776:\t\t\t\td_invalidate(dentry);\n 777:\t\t\t\tdput(dentry);\n 778:\t\t\t\tdentry = NULL;\n 779:\t\t\t\tgoto again;\n 780:\t\t\t}\n 781:\t\t}\n 782:\t\tif (!entry-\u003efh-\u003esize) {\n 783:\t\t\td_lookup_done(dentry);\n 784:\t\t\tgoto out;\n 785:\t\t}\n 786:\t\n 787:\t\tnfs_set_verifier(dentry, dir_verifier);\n 788:\t\tinode = nfs_fhget(dentry-\u003ed_sb, entry-\u003efh, entry-\u003efattr);\n 789:\t\talias = d_splice_alias(inode, dentry);\n" }
13/2	2026/09/30 04:57	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 16493 output: 37 thoughts: 209 Thoughts: Okay, let's break this down. Analyzing NFS Dentry Revalidation Right, so I'm digging into `nfs_neg_need_reval`. Seems pretty straightforward, but let's be meticulous. First, I see the conditional checks within the function. If we're creating something new (`LOOKUP_CREATE`) or dealing with a rename target (`LOOKUP_RENAME_TARGET`), there's no need to revalidate the negative dentry – makes sense. No need to thrash the server in that case. However, if it's an open call (`LOOKUP_OPEN`), the function returns 1. Aha, this is where that close-to-open semantics issue comes into play. The comment highlights that to ensure we hit the server on every open. Invalidating the dentry ensures exclusive access to the dentry for nfs_atomic_open. Finally, there's a check for `NFS_MOUNT_LOOKUP_CACHE_NONEG`. If that flag is set on the server, we also revalidate the negative dentry. I suspect this option is used when the mount itself wants to disable negative caching. I'll need to double check the semantics around that flag. Now I'll shift my attention to understanding how the revalidation actually happens. I'll need to go look at `__nfs_lookup_revalidate` and `block_revalidate`. I'm guessing `block_revalidate` will be handling the lower-level block invalidation aspects, and `__nfs_lookup_revalidate` will be coordinating the whole operation, perhaps driving the actual server interaction.
14/2	2026/09/30 04:58	tool	read-file	0m Args: { "File": "fs/nfs/dir.c", "FirstLine": 1835, "LineCount": 45 } Results: { "Contents": "1835:\t\treturn nfs_lookup_revalidate_done(dir, dentry, inode, error);\n1836:\t}\n1837:\t\n1838:\tstatic int\n1839:\t__nfs_lookup_revalidate(struct dentry dentry, unsigned int flags)\n1840:\t{\n1841:\t\tif (flags \u0026 LOOKUP_RCU) {\n1842:\t\t\tif (dentry-\u003ed_fsdata == NFS_FSDATA_BLOCKED)\n1843:\t\t\t\treturn -ECHILD;\n1844:\t\t} else {\n1845:\t\t\t/ Wait for unlink to complete - see unblock_revalidate() /\n1846:\t\t\twait_var_event(\u0026dentry-\u003ed_fsdata,\n1847:\t\t\t\t dentry-\u003ed_fsdata != NFS_FSDATA_BLOCKED);\n1848:\t\t}\n1849:\t\treturn 0;\n1850:\t}\n1851:\t\n1852:\tstatic int nfs_lookup_revalidate(struct inode dir, const struct qstr name,\n1853:\t\t\t\t\t struct dentry dentry, unsigned int flags)\n1854:\t{\n1855:\t\tif (__nfs_lookup_revalidate(dentry, flags))\n1856:\t\t\treturn -ECHILD;\n1857:\t\treturn nfs_do_lookup_revalidate(dir, name, dentry, flags);\n1858:\t}\n1859:\t\n1860:\tstatic void block_revalidate(struct dentry dentry)\n1861:\t{\n1862:\t\t/ old devname - just in case /\n1863:\t\tkfree(dentry-\u003ed_fsdata);\n1864:\t\n1865:\t\t/ Any new reference that could lead to an open\n1866:\t\t * will either:\n1867:\t\t * - take -\u003ed_lock in lookup_open() -\u003e d_lookup() or\n1868:\t\t * - will check d_seq in legitimize_mnt()\n1869:\t\t \n1870:\t\t Holding this lock and invalidating -\u003ed_seq ensures we cannot\n1871:\t\t * race with __nfs_lookup_revalidate().\n1872:\t\t /\n1873:\t\tlockdep_assert_held(\u0026dentry-\u003ed_lock);\n1874:\t\twrite_seqcount_invalidate(\u0026dentry-\u003ed_seq);\n1875:\t\n1876:\t\tdentry-\u003ed_fsdata = NFS_FSDATA_BLOCKED;\n1877:\t}\n1878:\t\n1879:\tstatic void unblock_revalidate(struct dentry dentry)\n" }
15/2	2026/09/30 04:58	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 17797 output: 37 thoughts: 14 Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience, and delivered as a first-person summary: Diving into `nfs_atomic_open` Alright, let's dissect `nfs_atomic_open`, shall we? My first instinct is to think about the inherent complexities. Atomic opens are always a fun challenge, especially in a distributed file system like NFS. The need for atomicity across a network introduces a whole slew of race conditions and synchronization hurdles that need to be carefully navigated. I immediately start mentally cataloging the various scenarios: concurrent opens, partial writes, crashes during the operation... the usual suspects. I'm thinking about the consistency models at play here too. NFSv3's lack of strong guarantees compared to NFSv4 makes me wonder if this function compensates for that. Is it using the filehandle for all the operations, locking at a high level, or something more clever? Are there any clever tricks to deal with the limitations of the underlying transport? I would be digging deep into how it interacts with the underlying RPC mechanisms - are there custom procedures or data structures involved? The performance characteristics are also paramount. Atomic opens are often used for important operations so speed is a critical concern, and I'd be looking for the bottlenecks. What kind of metadata does it touch? How often does it reach out to the server, and what does it do if the server is under load? I’d be checking for the use of caching in the code, or ways to perform operations in parallel to improve performance. I hope the code is structured in a clear and understandable manner, because this area is notoriously difficult to debug when there are issues. Finally, I’d be keeping an eye out for potential security vulnerabilities. Atomic operations can be tricky when it comes to permissions and access control. Does it check the client's credentials properly at every stage, or are there any opportunities for privilege escalation? Are there any potential for denial of service? In this area, I’d be especially keen to see the code's resilience in the face of malicious inputs. I hope this thing is hardened!
16/2	2026/09/30 04:58	tool	read-file	0m Args: { "File": "fs/nfs/dir.c", "FirstLine": 2160, "LineCount": 80 } Results: { "Contents": "2160:\t\t\tattr.ia_mode = mode;\n2161:\t\t}\n2162:\t\tif (open_flags \u0026 O_TRUNC) {\n2163:\t\t\tattr.ia_valid \|= ATTR_SIZE;\n2164:\t\t\tattr.ia_size = 0;\n2165:\t\t}\n2166:\t\n2167:\t\tctx = create_nfs_open_context(dentry, open_flags, file);\n2168:\t\terr = PTR_ERR(ctx);\n2169:\t\tif (IS_ERR(ctx))\n2170:\t\t\tgoto out;\n2171:\t\n2172:\t\ttrace_nfs_atomic_open_enter(dir, ctx, open_flags);\n2173:\t\tinode = NFS_PROTO(dir)-\u003eopen_context(dir, ctx, open_flags, \u0026attr, \u0026created);\n2174:\t\tif (created)\n2175:\t\t\tfile-\u003ef_mode \|= FMODE_CREATED;\n2176:\t\tif (IS_ERR(inode)) {\n2177:\t\t\terr = PTR_ERR(inode);\n2178:\t\t\ttrace_nfs_atomic_open_exit(dir, ctx, open_flags, err);\n2179:\t\t\tput_nfs_open_context(ctx);\n2180:\t\t\tswitch (err) {\n2181:\t\t\tcase -ENOENT:\n2182:\t\t\t\tif (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE))\n2183:\t\t\t\t\tdir_verifier = inode_peek_iversion_raw(dir);\n2184:\t\t\t\telse\n2185:\t\t\t\t\tdir_verifier = nfs_save_change_attribute(dir);\n2186:\t\t\t\tnfs_set_verifier(dentry, dir_verifier);\n2187:\t\t\t\td_splice_alias(NULL, dentry);\n2188:\t\t\t\tgoto out;\n2189:\t\t\tcase -EISDIR:\n2190:\t\t\tcase -ENOTDIR:\n2191:\t\t\t\tif (open_flags \u0026 __O_REGULAR) {\n2192:\t\t\t\t\terr = -EFTYPE;\n2193:\t\t\t\t\tbreak;\n2194:\t\t\t\t}\n2195:\t\t\t\tgoto no_open;\n2196:\t\t\tcase -ELOOP:\n2197:\t\t\t\tif (!(open_flags \u0026 O_NOFOLLOW))\n2198:\t\t\t\t\tgoto no_open;\n2199:\t\t\t\tbreak;\n2200:\t\t\t\t/* case -EINVAL: */\n2201:\t\t\tdefault:\n2202:\t\t\t\tbreak;\n2203:\t\t\t}\n2204:\t\t\td_drop(dentry);\n2205:\t\t\tgoto out;\n2206:\t\t}\n2207:\t\tfile-\u003ef_mode \|= FMODE_CAN_ODIRECT;\n2208:\t\tif (test_bit(NFS_CONTEXT_O_DIRECT, \u0026ctx-\u003eflags)) {\n2209:\t\t\tfile-\u003ef_flags \|= O_DIRECT;\n2210:\t\t\topen_flags \|= O_DIRECT;\n2211:\t\t}\n2212:\t\n2213:\t\terr = nfs_finish_open(ctx, ctx-\u003edentry, file, open_flags);\n2214:\t\ttrace_nfs_atomic_open_exit(dir, ctx, open_flags, err);\n2215:\t\tput_nfs_open_context(ctx);\n2216:\tout:\n2217:\t\treturn err;\n2218:\t\n2219:\tno_open:\n2220:\t\tres = nfs_lookup(dir, dentry, lookup_flags);\n2221:\t\tif (!res) {\n2222:\t\t\tinode = d_inode(dentry);\n2223:\t\t\tif ((lookup_flags \u0026 LOOKUP_DIRECTORY) \u0026\u0026 inode \u0026\u0026\n2224:\t\t\t !(S_ISDIR(inode-\u003ei_mode) \|\| S_ISLNK(inode-\u003ei_mode)))\n2225:\t\t\t\tres = ERR_PTR(-ENOTDIR);\n2226:\t\t\telse if (inode \u0026\u0026 S_ISREG(inode-\u003ei_mode))\n2227:\t\t\t\tres = ERR_PTR(-EOPENSTALE);\n2228:\t\t} else if (!IS_ERR(res)) {\n2229:\t\t\tinode = d_inode(res);\n2230:\t\t\tif ((lookup_flags \u0026 LOOKUP_DIRECTORY) \u0026\u0026 inode \u0026\u0026\n2231:\t\t\t !(S_ISDIR(inode-\u003ei_mode) \|\| S_ISLNK(inode-\u003ei_mode))) {\n2232:\t\t\t\tdput(res);\n2233:\t\t\t\tres = ERR_PTR(-ENOTDIR);\n2234:\t\t\t} else if (inode \u0026\u0026 S_ISREG(inode-\u003ei_mode)) {\n2235:\t\t\t\tdput(res);\n2236:\t\t\t\tres = ERR_PTR(-EOPENSTALE);\n2237:\t\t\t}\n2238:\t\t}\n2239:\t\treturn finish_no_open(file, res);\n" }
17/2	2026/09/30 04:58	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 19574 output: 27 thoughts: 706 Thoughts: Analyzing NFS Client File Operations and Configuration Okay, let's dive into this NFS code, specifically focusing on how links and renames are handled on the client side. I need to get a clear picture of the logic and potential points of interest. First, I'm looking at `fs/nfs/dir.c`. I see `nfs_link` has a seemingly straightforward process: it sets a verifier, increases the inode's reference count, and then aliases the inode to the dentry if there's no initial error. If there is an initial error, the dentry is dropped. That's pretty standard so far. Now, `nfs_rename` is more interesting. It looks like `d_duplicate` is used to create a copy of the target dentry's name. Then, `nfs_sillyrename` is called on the existing target. After this, there's a check to see if a new dentry was actually created and handled with `d_lookup_done` and `dput`. The interesting part is the use of `nfs_sillyrename`. I need to figure out what this is doing. So I'm now looking at `fs/nfs/unlink.c` and specifically `nfs_sillyrename`. This is where the magic (or potential complexity) is. It creates a "silly" name using `SILLYNAME_PREFIX`, a file ID, and a counter. The code attempts to allocate a dentry using the silly name and then checks whether the silly name already exists. The use of `d_alloc_trylock` and the `goto newname` construct seem to be handling the case of concurrent lookups or name collisions. The code appears to be attempting to find a unique name on the NFS server by incrementing the sillycounter until it finds a unique entry. Then, it attempts to lookup the entry on the server. If this lookup succeeds, or if the server has an existing positive dentry, the counter is incremented and the process repeats. If the lookup fails and the name is not positive, `ihold` is called, likely because it is about to unlink something that may be in use. It looks like it could be dangerous to unlink the file. Overall, it seems like the client is carefully handling potential conflicts during rename operations by using this "sillyrename" mechanism to create temporary, unique names on the server. I also need to verify that this is implemented correctly. I will want to be sure it does not lead to potential security issues or denial of service issues. Finally, I need to see what configuration options are available for the NFS client. I'll need to check the Kconfig files in `fs/nfs/Makefile` and `fs/nfs/Kconfig` to determine what features can be enabled or disabled and how these options might impact the behavior I've just analyzed.
18/2	2026/09/30 04:58	tool	grepper	0m Args: { "Expression": "fs/nfs/", "PathPrefix": "fs/" } Results: { "Output": "fs/Kconfig=351=if NETWORK_FILESYSTEMS\nfs/Kconfig-352-\nfs/Kconfig:353:source \"fs/nfs/Kconfig\"\nfs/Kconfig-354-source \"fs/nfsd/Kconfig\"\n--\nfs/ceph/io.c-7- \nfs/ceph/io.c:8: Heavily borrowed from equivalent code in fs/nfs/io.c\nfs/ceph/io.c-9- /\n--\nfs/nfs/blocklayout/blocklayout.c-1-/\nfs/nfs/blocklayout/blocklayout.c:2: * linux/fs/nfs/blocklayout/blocklayout.c\nfs/nfs/blocklayout/blocklayout.c-3- \n--\nfs/nfs/blocklayout/blocklayout.h-1-/\nfs/nfs/blocklayout/blocklayout.h:2: * linux/fs/nfs/blocklayout/blocklayout.h\nfs/nfs/blocklayout/blocklayout.h-3- \n--\nfs/nfs/cache_lib.c-2-/\nfs/nfs/cache_lib.c:3: * linux/fs/nfs/cache_lib.c\nfs/nfs/cache_lib.c-4- \n--\nfs/nfs/callback.c-2-/\nfs/nfs/callback.c:3: * linux/fs/nfs/callback.c\nfs/nfs/callback.c-4- \n--\nfs/nfs/callback.h-2-/\nfs/nfs/callback.h:3: * linux/fs/nfs/callback.h\nfs/nfs/callback.h-4- \n--\nfs/nfs/callback_proc.c-2-/\nfs/nfs/callback_proc.c:3: * linux/fs/nfs/callback_proc.c\nfs/nfs/callback_proc.c-4- \n--\nfs/nfs/callback_xdr.c-2-/\nfs/nfs/callback_xdr.c:3: * linux/fs/nfs/callback_xdr.c\nfs/nfs/callback_xdr.c-4- \n--\nfs/nfs/delegation.c-2-/\nfs/nfs/delegation.c:3: * linux/fs/nfs/delegation.c\nfs/nfs/delegation.c-4- \n--\nfs/nfs/delegation.h-2-/\nfs/nfs/delegation.h:3: * linux/fs/nfs/delegation.h\nfs/nfs/delegation.h-4- \n--\nfs/nfs/dir.c-2-/\nfs/nfs/dir.c:3: * linux/fs/nfs/dir.c\nfs/nfs/dir.c-4- \n--\nfs/nfs/dir.c=2612=EXPORT_SYMBOL_GPL(nfs_unlink);\n--\nfs/nfs/dir.c-2620- because it needs a file handle to create an in-core inode (see\nfs/nfs/dir.c:2621: * fs/nfs/inode.c:nfs_fhget). We only have a file handle after the\nfs/nfs/dir.c-2622- * symlink request has completed on the server.\n--\nfs/nfs/direct.c-2-/\nfs/nfs/direct.c:3: linux/fs/nfs/direct.c\nfs/nfs/direct.c-4- \n--\nfs/nfs/dns_resolve.c-2-/\nfs/nfs/dns_resolve.c:3: * linux/fs/nfs/dns_resolve.c\nfs/nfs/dns_resolve.c-4- \n--\nfs/nfs/file.c-2-/\nfs/nfs/file.c:3: * linux/fs/nfs/file.c\nfs/nfs/file.c-4- \n--\nfs/nfs/fs_context.c-2-/\nfs/nfs/fs_context.c:3: * linux/fs/nfs/fs_context.c\nfs/nfs/fs_context.c-4- \n--\nfs/nfs/fs_context.c-9- \nfs/nfs/fs_context.c:10: * Split from fs/nfs/super.c by David Howells \u003cdhowells@redhat.com\u003e\nfs/nfs/fs_context.c-11- /\n--\nfs/nfs/inode.c-2-/\nfs/nfs/inode.c:3: * linux/fs/nfs/inode.c\nfs/nfs/inode.c-4- \n--\nfs/nfs/iostat.h-2-/\nfs/nfs/iostat.h:3: * linux/fs/nfs/iostat.h\nfs/nfs/iostat.h-4- \n--\nfs/nfs/namespace.c-2-/\nfs/nfs/namespace.c:3: * linux/fs/nfs/namespace.c\nfs/nfs/namespace.c-4- \n--\nfs/nfs/nfs2xdr.c-2-/\nfs/nfs/nfs2xdr.c:3: * linux/fs/nfs/nfs2xdr.c\nfs/nfs/nfs2xdr.c-4- \n--\nfs/nfs/nfs3proc.c-2-/\nfs/nfs/nfs3proc.c:3: * linux/fs/nfs/nfs3proc.c\nfs/nfs/nfs3proc.c-4- \n--\nfs/nfs/nfs3xdr.c-2-/\nfs/nfs/nfs3xdr.c:3: * linux/fs/nfs/nfs3xdr.c\nfs/nfs/nfs3xdr.c-4- \n--\nfs/nfs/nfs4_fs.h-2-/\nfs/nfs/nfs4_fs.h:3: * linux/fs/nfs/nfs4_fs.h\nfs/nfs/nfs4_fs.h-4- \n--\nfs/nfs/nfs4file.c-2-/\nfs/nfs/nfs4file.c:3: * linux/fs/nfs/file.c\nfs/nfs/nfs4file.c-4- \n--\nfs/nfs/nfs4idmap.c-1-/\nfs/nfs/nfs4idmap.c:2: * fs/nfs/idmap.c\nfs/nfs/nfs4idmap.c-3- \n--\nfs/nfs/nfs4idmap.h-1-/\nfs/nfs/nfs4idmap.h:2: * fs/nfs/nfs4idmap.h\nfs/nfs/nfs4idmap.h-3- \n--\nfs/nfs/nfs4namespace.c-2-/\nfs/nfs/nfs4namespace.c:3: * linux/fs/nfs/nfs4namespace.c\nfs/nfs/nfs4namespace.c-4- \n--\nfs/nfs/nfs4proc.c-1-/\nfs/nfs/nfs4proc.c:2: * fs/nfs/nfs4proc.c\nfs/nfs/nfs4proc.c-3- \n--\nfs/nfs/nfs4renewd.c-1-/\nfs/nfs/nfs4renewd.c:2: * fs/nfs/nfs4renewd.c\nfs/nfs/nfs4renewd.c-3- \n--\nfs/nfs/nfs4session.c-2-/\nfs/nfs/nfs4session.c:3: * fs/nfs/nfs4session.c\nfs/nfs/nfs4session.c-4- \n--\nfs/nfs/nfs4session.h-2-/\nfs/nfs/nfs4session.h:3: * fs/nfs/nfs4session.h\nfs/nfs/nfs4session.h-4- \n--\nfs/nfs/nfs4state.c-1-/\nfs/nfs/nfs4state.c:2: * fs/nfs/nfs4state.c\nfs/nfs/nfs4state.c-3- \n--\nfs/nfs/nfs4sysctl.c-2-/\nfs/nfs/nfs4sysctl.c:3: * linux/fs/nfs/nfs4sysctl.c\nfs/nfs/nfs4sysctl.c-4- \n--\nfs/nfs/nfs4xdr.c-1-/\nfs/nfs/nfs4xdr.c:2: * fs/nfs/nfs4xdr.c\nfs/nfs/nfs4xdr.c-3- \n--\nfs/nfs/pagelist.c-2-/\nfs/nfs/pagelist.c:3: * linux/fs/nfs/pagelist.c\nfs/nfs/pagelist.c-4- \n--\nfs/nfs/proc.c-2-/\nfs/nfs/proc.c:3: * linux/fs/nfs/proc.c\nfs/nfs/proc.c-4- \n--\nfs/nfs/read.c-2-/\nfs/nfs/read.c:3: * linux/fs/nfs/read.c\nfs/nfs/read.c-4- \n--\nfs/nfs/read.c-6- \nfs/nfs/read.c:7: * Partial copy of Linus' read cache modifications to fs/nfs/file.c\nfs/nfs/read.c-8- * modified for async RPC by okir@monad.swb.de\n--\nfs/nfs/super.c-2-/\nfs/nfs/super.c:3: linux/fs/nfs/super.c\nfs/nfs/super.c-4- \n--\nfs/nfs/symlink.c-2-/\nfs/nfs/symlink.c:3: * linux/fs/nfs/symlink.c\nfs/nfs/symlink.c-4- \n--\nfs/nfs/sysctl.c-2-/\nfs/nfs/sysctl.c:3: * linux/fs/nfs/sysctl.c\nfs/nfs/sysctl.c-4- \n--\nfs/nfs/unlink.c-2-/\nfs/nfs/unlink.c:3: * linux/fs/nfs/unlink.c\nfs/nfs/unlink.c-4- \n--\nfs/nfs/write.c-2-/\nfs/nfs/write.c:3: * linux/fs/nfs/write.c\nfs/nfs/write.c-4- \n--\nfs/nfsd/nfsctl.c=2922=static void __exit exit_nfsd(void)\nfs/nfsd/nfsctl.c-2923-{\nfs/nfsd/nfsctl.c:2924:\tremove_proc_entry(\"fs/nfs/exports\", NULL);\nfs/nfsd/nfsctl.c-2925-\tremove_proc_entry(\"fs/nfs\", NULL);\n--\nfs/smb/client/inode.c=1811=cifs_rename_pending_delete(const char full_path, struct dentry dentry,\n--\nfs/smb/client/inode.c-1937-\nfs/smb/client/inode.c:1938:/ copied from fs/nfs/dir.c with small changes */\nfs/smb/client/inode.c-1939-static void\n" }
19/2	2026/09/30 04:58	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 23905 output: 32 thoughts: 19 Thoughts: Here's my take on those thoughts: Navigating the Filesystem Landscape Alright, let's dive into this. Based on what I'm looking at, my initial focus will be on the `fs/nfs/Makefile` and `fs/nfs/Kconfig` files. That's a good starting point. The Makefile should reveal the build process for the NFS component – the dependencies, compilation flags, and linking steps. A quick scan should expose how the NFS client and server modules are constructed within this kernel build environment. Then, I'll need to scrutinize `fs/nfs/Kconfig`. This file dictates the configuration options associated with NFS – what features are enabled, disabled, and configurable. I'm keen to understand the conditional compilation logic and default settings, which will give me a better understanding of the various NFS flavors supported, security options and performance tweaks at my disposal. This will allow me to build a picture of the overall architecture and configurability of the NFS implementation in this codebase. From there, I'll need to see how these two files are linked together, perhaps a `depends on` entry in the `Kconfig` files used in the `Makefile` and vice versa, which is a good place to start the exploration.
20/2	2026/09/30 04:58	tool	read-file	0m Args: { "File": "fs/nfs/Makefile", "FirstLine": 1, "LineCount": 40 } Results: { "Contents": " 1:\t# SPDX-License-Identifier: GPL-2.0\n 2:\t#\n 3:\t# Makefile for the Linux nfs filesystem routines.\n 4:\t#\n 5:\t\n 6:\tobj-$(CONFIG_NFS_FS) += nfs.o\n 7:\t\n 8:\tCFLAGS_nfstrace.o += -I$(src)\n 9:\tnfs-y \t\t\t:= client.o dir.o file.o getroot.o inode.o super.o \\\n 10:\t\t\t\t io.o direct.o pagelist.o read.o symlink.o unlink.o \\\n 11:\t\t\t\t write.o namespace.o mount_clnt.o nfstrace.o \\\n 12:\t\t\t\t export.o sysfs.o fs_context.o\n 13:\tnfs-$(CONFIG_ROOT_NFS)\t+= nfsroot.o\n 14:\tnfs-$(CONFIG_SYSCTL)\t+= sysctl.o\n 15:\tnfs-$(CONFIG_NFS_FSCACHE) += fscache.o\n 16:\tnfs-$(CONFIG_NFS_LOCALIO) += localio.o\n 17:\t\n 18:\tobj-$(CONFIG_NFS_V2) += nfsv2.o\n 19:\tnfsv2-y := nfs2super.o proc.o nfs2xdr.o\n 20:\t\n 21:\tobj-$(CONFIG_NFS_V3) += nfsv3.o\n 22:\tnfsv3-y := nfs3super.o nfs3client.o nfs3proc.o nfs3xdr.o\n 23:\tnfsv3-$(CONFIG_NFS_V3_ACL) += nfs3acl.o\n 24:\t\n 25:\tobj-$(CONFIG_NFS_V4) += nfsv4.o\n 26:\tCFLAGS_nfs4trace.o += -I$(src)\n 27:\tnfsv4-y := nfs4proc.o nfs4xdr.o nfs4state.o nfs4renewd.o nfs4super.o nfs4file.o \\\n 28:\t\t delegation.o nfs4idmap.o callback.o callback_xdr.o callback_proc.o \\\n 29:\t\t nfs4namespace.o nfs4getroot.o nfs4client.o nfs4session.o \\\n 30:\t\t dns_resolve.o nfs4trace.o pnfs.o pnfs_dev.o pnfs_nfs.o\n 31:\tnfsv4-$(CONFIG_NFS_USE_LEGACY_DNS) += cache_lib.o\n 32:\tnfsv4-$(CONFIG_SYSCTL)\t+= nfs4sysctl.o\n 33:\tnfsv4-$(CONFIG_NFS_V4_0)\t+= nfs40client.o nfs40proc.o\n 34:\tnfsv4-$(CONFIG_NFS_V4_2)\t+= nfs42proc.o nfs42xattr.o\n 35:\t\n 36:\tobj-$(CONFIG_PNFS_FILE_LAYOUT) += filelayout/\n 37:\tobj-$(CONFIG_PNFS_BLOCK) += blocklayout/\n 38:\tobj-$(CONFIG_PNFS_FLEXFILE_LAYOUT) += flexfilelayout/\n" }
21/2	2026/09/30 04:58	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 25076 output: 33 thoughts: 17 Thoughts: Here's a summary of my thought process: Diving into Kconfig for Dependencies Okay, so I'm thinking, before I go any further down this rabbit hole, I need to get a full picture of the dependencies. It's time to check `fs/nfs/Kconfig` – and really, the broader Kconfig landscape related to NFS – to see if there are any obvious flags or options that control these behaviours. I want to identify the configuration options that influence the behavior of the NFS filesystems. That's the key to truly understanding the current state. I need to be thorough.
22/2	2026/09/30 04:58	tool	read-file	0m Args: { "File": "fs/nfs/Kconfig", "FirstLine": 1, "LineCount": 50 } Results: { "Contents": " 1:\t# SPDX-License-Identifier: GPL-2.0-only\n 2:\tconfig NFS_FS\n 3:\t\ttristate \"NFS client support\"\n 4:\t\tdepends on INET \u0026\u0026 FILE_LOCKING \u0026\u0026 MULTIUSER\n 5:\t\tselect CRC32\n 6:\t\tselect LOCKD\n 7:\t\tselect SUNRPC\n 8:\t\tselect NFS_COMMON\n 9:\t\tselect NFS_ACL_SUPPORT if NFS_V3_ACL\n 10:\t\thelp\n 11:\t\t Choose Y here if you want to access files residing on other\n 12:\t\t computers using Sun's Network File System protocol. To compile\n 13:\t\t this file system support as a module, choose M here: the module\n 14:\t\t will be called nfs.\n 15:\t\n 16:\t\t To mount file systems exported by NFS servers, you also need to\n 17:\t\t install the user space mount.nfs command which can be found in\n 18:\t\t the Linux nfs-utils package, available from http://linux-nfs.org/.\n 19:\t\t Information about using the mount command is available in the\n 20:\t\t mount(8) man page. More detail about the Linux NFS client\n 21:\t\t implementation is available via the nfs(5) man page.\n 22:\t\n 23:\t\t Below you can choose which versions of the NFS protocol are\n 24:\t\t available in the kernel to mount NFS servers. Support for NFS\n 25:\t\t version 2 (RFC 1094) is always available when NFS_FS is selected.\n 26:\t\n 27:\t\t To configure a system which mounts its root file system via NFS\n 28:\t\t at boot time, say Y here, select \"Kernel level IP\n 29:\t\t autoconfiguration\" in the NETWORK menu, and select \"Root file\n 30:\t\t system on NFS\" below. You cannot compile this file system as a\n 31:\t\t module in this case.\n 32:\t\n 33:\t\t If unsure, say N.\n 34:\t\n 35:\tconfig NFS_V2\n 36:\t\ttristate \"NFS client support for NFS version 2\"\n 37:\t\tdepends on NFS_FS\n 38:\t\tdefault n\n 39:\t\thelp\n 40:\t\t This option enables support for version 2 of the NFS protocol\n 41:\t\t (RFC 1094) in the kernel's NFS client.\n 42:\t\n 43:\t\t If unsure, say N.\n 44:\t\n 45:\tconfig NFS_V3\n 46:\t\ttristate \"NFS client support for NFS version 3\"\n 47:\t\tdepends on NFS_FS\n 48:\t\tdefault y\n 49:\t\thelp\n 50:\t\t This option enables support for version 3 of the NFS protocol\n" }
23/2	2026/09/30 04:58	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 25988 output: 34 thoughts: 18 Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience: Examining NFSv4 Configuration Alright, let's dive in. My immediate thought is to zero in on the NFSv4 configuration options, and the first place I'm going to look is the `fs/nfs/Kconfig` file. That's the standard location for core NFS-related configuration within the kernel source. I want to quickly ascertain the state of the NFSv4 support, understand the available configuration knobs, and perhaps refresh my memory on any recent additions or changes to its setup. Knowing the Kconfig options will give me a solid foundation for evaluating how NFSv4 is currently handled within the kernel build process and ultimately how it's enabled or disabled. It's a fundamental step before digging deeper into the actual code.
24/2	2026/09/30 04:58	tool	read-file	0m Args: { "File": "fs/nfs/Kconfig", "FirstLine": 51, "LineCount": 60 } Results: { "Contents": " 51:\t\t (RFC 1813) in the kernel's NFS client.\n 52:\t\n 53:\t\t If unsure, say Y.\n 54:\t\n 55:\tconfig NFS_V3_ACL\n 56:\t\tbool \"NFS client support for the NFSv3 ACL protocol extension\"\n 57:\t\tdepends on NFS_V3\n 58:\t\thelp\n 59:\t\t Some NFS servers support an auxiliary NFSv3 ACL protocol that\n 60:\t\t Sun added to Solaris but never became an official part of the\n 61:\t\t NFS version 3 protocol. This protocol extension allows\n 62:\t\t applications on NFS clients to manipulate POSIX Access Control\n 63:\t\t Lists on files residing on NFS servers. NFS servers enforce\n 64:\t\t ACLs on local files whether this protocol is available or not.\n 65:\t\n 66:\t\t Choose Y here if your NFS server supports the Solaris NFSv3 ACL\n 67:\t\t protocol extension and you want your NFS client to allow\n 68:\t\t applications to access and modify ACLs on files on the server.\n 69:\t\n 70:\t\t Most NFS servers don't support the Solaris NFSv3 ACL protocol\n 71:\t\t extension. You can choose N here or specify the \"noacl\" mount\n 72:\t\t option to prevent your NFS client from trying to use the NFSv3\n 73:\t\t ACL protocol.\n 74:\t\n 75:\t\t If unsure, say N.\n 76:\t\n 77:\tconfig NFS_V4\n 78:\t\ttristate \"NFS client support for NFS version 4\"\n 79:\t\tdepends on NFS_FS\n 80:\t\tselect KEYS\n 81:\t\tselect SUNRPC_BACKCHANNEL\n 82:\t\thelp\n 83:\t\t This option enables support for version 4.1 of the NFS protocol\n 84:\t\t (RFC 5661) in the kernel's NFS client.\n 85:\t\n 86:\t\t To mount NFS servers using NFSv4, you also need to install user\n 87:\t\t space programs which can be found in the Linux nfs-utils package,\n 88:\t\t available from http://linux-nfs.org/.\n 89:\t\n 90:\t\t If unsure, say N.\n 91:\t\n 92:\tconfig NFS_SWAP\n 93:\t\tbool \"Provide swap over NFS support\"\n 94:\t\tdefault n\n 95:\t\tdepends on NFS_FS \u0026\u0026 SWAP\n 96:\t\tselect SUNRPC_SWAP\n 97:\t\thelp\n 98:\t\t This option enables swapon to work on files located on NFS mounts.\n 99:\t\n 100:\tconfig NFS_V4_0\n 101:\t\tbool \"NFS client support for NFSv4.0\"\n 102:\t\tdepends on NFS_V4\n 103:\t\tdefault y\n 104:\t\thelp\n 105:\t\t This option enables support for minor version 0 of the NFSv4 protocol\n 106:\t\t (RFC 3530) in the kernel's NFS client.\n 107:\t\n 108:\t\t If unsure, say N.\n 109:\t\n 110:\tconfig NFS_V4_2\n" }
25/2	2026/09/30 04:58	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 27065 output: 38 thoughts: 1576 Thoughts: WorthFuzzing=true - NFS dcache and locking interactions Okay, so looking at these code changes, here's what I'm thinking. First, the compilation context is clear: `fs/nfs/nfs4proc.c` when `CONFIG_NFS_V4` is enabled, and `fs/nfs/dir.c` and `fs/nfs/unlink.c` when `CONFIG_NFS_FS` is enabled. Both configurations are relevant here. Now, let's determine if we should fuzz the code. The primary thing to keep in mind is, is the modified code reachable? Can it be executed in standard virtualized environments, like QEMU or GCE? Well, NFS client code is standard Linux filesystem code. It's accessible via VFS syscalls - `open`, `link`, `unlink`, `rename`, `readdir`, etc. - on NFS mounts. This means it's definitely reachable. Now, considering the changes: we're seeing shifts in how the dcache interacts with NFS. The code switches from using `full_name_hash`, `d_lookup`, and `d_alloc_parallel` to `d_alloc_trylock`, revalidates negative dentries on open, simplifies memory barrier/acquire logic, and adds `write_seqcount_invalidate`. There's major restructuring of dentry handling in `nfs_atomic_open`, moving `d_drop` around, and replacing `d_add` with `d_splice_alias` in `nfs_link`. In addition, there's a replacement of `d_alloc` with `d_duplicate` in `nfs_rename`, and a removal of `d_drop` before `d_splice_alias` in `_nfs4_open_and_get_state`. The modifications also include using hash computation before `d_alloc_parallel`, rewriting the sillyrename lookup loop. We're talking about core VFS dcache interactions, locking, race handling, and error unwind paths for NFS. Dentry lifecycle, specifically how `d_alloc_trylock`, `d_duplicate`, `d_splice_alias`, `d_lookup_done`, and `d_drop` are handled. These are notoriously tricky, and prone to race conditions, reference counting issues, deadlocks, and even use-after-frees. This is a big red flag – this screams "worth fuzzing". This isn't just a minor tweak; it's a fundamental change to how the NFS client interacts with the VFS. This patch is definitely WorthFuzzing=true. Now, let's think about FocusSymbols and EnableConfigs. The goal is to focus on specific feature logic and entrypoints. We want to avoid listing ubiquitous functions. All the changes are in `.c` files, so we don't have to deal with static inline functions. The modified functions in `fs/nfs/dir.c` are: `nfs_prime_dcache`, `nfs_neg_need_reval`, `__nfs_lookup_revalidate` (called by `nfs_lookup_revalidate`), `nfs_lookup_revalidate`, `block_revalidate`, `nfs_atomic_open`, `nfs_add_or_obtain`, `nfs_link`, and `nfs_rename`. In `fs/nfs/nfs4proc.c` we have `_nfs4_open_and_get_state` and `nfs4_proc_open`. In `fs/nfs/unlink.c` there is `nfs_call_unlink` and `nfs_sillyrename`. However, the key functions that we want to enable are `nfs_atomic_open`, `nfs_rename`, `nfs_link`, `nfs_sillyrename`, `nfs_prime_dcache`, and `nfs_neg_need_reval`. These are non-static functions - so we can directly enable them. They're all entrypoints into key logic and altered data flows in the dcache interaction, and should be excellent symbols to focus fuzzing on.
26/2	2026/09/30 04:58	tool	grepper	0m Args: { "Expression": "^(int\|void\|struct dentry \\) nfs_", "PathPrefix": "fs/nfs/" } Results:* { "Output": "\nFull output is too long, showing 500 out of 1476 lines.\nUse more precise expression if possible.\n\nfs/nfs/cache_lib.c=32=MODULE_PARM_DESC(cache_getent_timeout, \"Timeout (in seconds) after which \"\n--\nfs/nfs/cache_lib.c-34-\nfs/nfs/cache_lib.c:35:int nfs_cache_upcall(struct cache_detail cd, char entry_name)\nfs/nfs/cache_lib.c-36-{\n--\nfs/nfs/cache_lib.c-67- /\nfs/nfs/cache_lib.c:68:void nfs_cache_defer_req_put(struct nfs_cache_defer_req dreq)\nfs/nfs/cache_lib.c-69-{\n--\nfs/nfs/cache_lib.c=95=struct nfs_cache_defer_req nfs_cache_defer_req_alloc(void)\n--\nfs/nfs/cache_lib.c-107-\nfs/nfs/cache_lib.c:108:int nfs_cache_wait_for_upcall(struct nfs_cache_defer_req dreq)\nfs/nfs/cache_lib.c-109-{\n--\nfs/nfs/cache_lib.c-115-\nfs/nfs/cache_lib.c:116:int nfs_cache_register_sb(struct super_block sb, struct cache_detail cd)\nfs/nfs/cache_lib.c-117-{\n--\nfs/nfs/cache_lib.c-126-\nfs/nfs/cache_lib.c:127:int nfs_cache_register_net(struct net net, struct cache_detail cd)\nfs/nfs/cache_lib.c-128-{\n--\nfs/nfs/cache_lib.c-142-\nfs/nfs/cache_lib.c:143:void nfs_cache_unregister_sb(struct super_block sb, struct cache_detail cd)\nfs/nfs/cache_lib.c-144-{\n--\nfs/nfs/cache_lib.c-147-\nfs/nfs/cache_lib.c:148:void nfs_cache_unregister_net(struct net net, struct cache_detail cd)\nfs/nfs/cache_lib.c-149-{\n--\nfs/nfs/callback.c=173=static struct svc_serv nfs_callback_create_svc(int minorversion)\n--\nfs/nfs/callback.c-207- /\nfs/nfs/callback.c:208:int nfs_callback_up(u32 minorversion, struct rpc_xprt xprt)\nfs/nfs/callback.c-209-{\n--\nfs/nfs/callback.c-250- /\nfs/nfs/callback.c:251:void nfs_callback_down(int minorversion, struct net net, struct rpc_xprt xprt)\nfs/nfs/callback.c-252-{\n--\nfs/nfs/client.c=214=static void nfs_cb_idr_remove_locked(struct nfs_client clp)\n--\nfs/nfs/client.c-223-\nfs/nfs/client.c:224:void nfs_cb_idr_remove(struct nfs_client clp)\nfs/nfs/client.c-225-{\n--\nfs/nfs/client.c=248=static void pnfs_init_server(struct nfs_server server)\n--\nfs/nfs/client.c-256- /\nfs/nfs/client.c:257:void nfs_free_client(struct nfs_client clp)\nfs/nfs/client.c-258-{\n--\nfs/nfs/client.c=271=EXPORT_SYMBOL_GPL(nfs_free_client);\n--\nfs/nfs/client.c-275- /\nfs/nfs/client.c:276:void nfs_put_client(struct nfs_client clp)\nfs/nfs/client.c-277-{\n--\nfs/nfs/client.c=377=EXPORT_SYMBOL_GPL(nfs_client_init_is_complete);\n--\nfs/nfs/client.c-384- /\nfs/nfs/client.c:385:int nfs_client_init_status(const struct nfs_client clp)\nfs/nfs/client.c-386-{\n--\nfs/nfs/client.c=394=EXPORT_SYMBOL_GPL(nfs_client_init_status);\nfs/nfs/client.c-395-\nfs/nfs/client.c:396:int nfs_wait_client_init_complete(const struct nfs_client clp)\nfs/nfs/client.c-397-{\n--\nfs/nfs/client.c=473=EXPORT_SYMBOL_GPL(nfs_get_client);\n--\nfs/nfs/client.c-477- /\nfs/nfs/client.c:478:void nfs_mark_client_ready(struct nfs_client clp, int state)\nfs/nfs/client.c-479-{\n--\nfs/nfs/client.c=484=EXPORT_SYMBOL_GPL(nfs_mark_client_ready);\n--\nfs/nfs/client.c-488- /\nfs/nfs/client.c:489:void nfs_init_timeout_values(struct rpc_timeout to, int proto,\nfs/nfs/client.c-490-\t\t\t\t int timeo, int retrans)\n--\nfs/nfs/client.c=527=EXPORT_SYMBOL_GPL(nfs_init_timeout_values);\n--\nfs/nfs/client.c-531- /\nfs/nfs/client.c:532:int nfs_create_rpc_client(struct nfs_client clp,\nfs/nfs/client.c-533-\t\t\t const struct nfs_client_initdata cl_init,\n--\nfs/nfs/client.c=601=static int nfs_start_lockd(struct nfs_server server)\n--\nfs/nfs/client.c-645- /\nfs/nfs/client.c:646:int nfs_init_server_rpcclient(struct nfs_server server,\nfs/nfs/client.c-647-\t\tconst struct rpc_timeout timeo,\n--\nfs/nfs/client.c=705=static void nfs4_server_set_init_caps(struct nfs_server server)\n--\nfs/nfs/client.c-724-\nfs/nfs/client.c:725:void nfs_server_set_init_caps(struct nfs_server server)\nfs/nfs/client.c-726-{\n--\nfs/nfs/client.c=927=static int nfs_probe_fsinfo(struct nfs_server server, struct nfs_fh mntfh, struct nfs_fattr fattr)\n--\nfs/nfs/client.c-989- /\nfs/nfs/client.c:990:int nfs_probe_server(struct nfs_server server, struct nfs_fh mntfh)\nfs/nfs/client.c-991-{\n--\nfs/nfs/client.c=1006=EXPORT_SYMBOL_GPL(nfs_probe_server);\n--\nfs/nfs/client.c-1010- /\nfs/nfs/client.c:1011:void nfs_server_copy_userdata(struct nfs_server target, struct nfs_server source)\nfs/nfs/client.c-1012-{\n--\nfs/nfs/client.c=1029=EXPORT_SYMBOL_GPL(nfs_server_copy_userdata);\nfs/nfs/client.c-1030-\nfs/nfs/client.c:1031:void nfs_server_insert_lists(struct nfs_server server)\nfs/nfs/client.c-1032-{\n--\nfs/nfs/client.c=1043=EXPORT_SYMBOL_GPL(nfs_server_insert_lists);\nfs/nfs/client.c-1044-\nfs/nfs/client.c:1045:void nfs_server_remove_lists(struct nfs_server server)\nfs/nfs/client.c-1046-{\n--\nfs/nfs/client.c=1123=static void delayed_free(struct rcu_head p)\n--\nfs/nfs/client.c-1133- /\nfs/nfs/client.c:1134:void nfs_free_server(struct nfs_server server)\nfs/nfs/client.c-1135-{\n--\nfs/nfs/client.c=1288=EXPORT_SYMBOL_GPL(nfs_clone_server);\nfs/nfs/client.c-1289-\nfs/nfs/client.c:1290:void nfs_clients_init(struct net net)\nfs/nfs/client.c-1291-{\n--\nfs/nfs/client.c-1308-\nfs/nfs/client.c:1309:void nfs_clients_exit(struct net net)\nfs/nfs/client.c-1310-{\n--\nfs/nfs/client.c=1451=static int nfs_volume_list_show(struct seq_file m, void v)\n--\nfs/nfs/client.c-1488-\nfs/nfs/client.c:1489:int nfs_fs_proc_net_init(struct net net)\nfs/nfs/client.c-1490-{\n--\nfs/nfs/client.c-1516-\nfs/nfs/client.c:1517:void nfs_fs_proc_net_exit(struct net net)\nfs/nfs/client.c-1518-{\n--\nfs/nfs/client.c=1525=int __init nfs_fs_proc_init(void)\n--\nfs/nfs/client.c-1547- /\nfs/nfs/client.c:1548:void nfs_fs_proc_exit(void)\nfs/nfs/client.c-1549-{\n--\nfs/nfs/delegation.c=52=static void nfs_mark_delegation_revoked(struct nfs_server server,\n--\nfs/nfs/delegation.c-75-\nfs/nfs/delegation.c:76:void nfs_put_delegation(struct nfs_delegation delegation)\nfs/nfs/delegation.c-77-{\n--\nfs/nfs/delegation.c-86- /\nfs/nfs/delegation.c:87:void nfs_mark_delegation_referenced(struct nfs_delegation delegation)\nfs/nfs/delegation.c-88-{\n--\nfs/nfs/delegation.c=212=static int nfs_delegation_claim_opens(struct inode inode,\n--\nfs/nfs/delegation.c-261- /\nfs/nfs/delegation.c:262:void nfs_inode_reclaim_delegation(struct inode inode, const struct cred cred,\nfs/nfs/delegation.c-263-\t\t\t\t fmode_t type, const nfs4_stateid stateid,\n--\nfs/nfs/delegation.c=411=nfs_update_inplace_delegation(struct nfs_server server,\n--\nfs/nfs/delegation.c-440- /\nfs/nfs/delegation.c:441:int nfs_inode_set_delegation(struct inode inode, const struct cred cred,\nfs/nfs/delegation.c-442-\t\t\t fmode_t type, const nfs4_stateid stateid,\n--\nfs/nfs/delegation.c=739=static bool nfs_client_clear_delayed_delegations(struct nfs_client clp)\n--\nfs/nfs/delegation.c-768- /\nfs/nfs/delegation.c:769:int nfs_client_return_marked_delegations(struct nfs_client clp)\nfs/nfs/delegation.c-770-{\n--\nfs/nfs/delegation.c-788- /\nfs/nfs/delegation.c:789:void nfs_inode_evict_delegation(struct inode inode)\nfs/nfs/delegation.c-790-{\n--\nfs/nfs/delegation.c=964=static void nfs_delegation_run_state_manager(struct nfs_client clp)\n--\nfs/nfs/delegation.c-974- /\nfs/nfs/delegation.c:975:void nfs_expire_all_delegations(struct nfs_client clp)\nfs/nfs/delegation.c-976-{\n--\nfs/nfs/delegation.c-991- /\nfs/nfs/delegation.c:992:void nfs_server_return_all_delegations(struct nfs_server server)\nfs/nfs/delegation.c-993-{\n--\nfs/nfs/delegation.c=1010=static void nfs_mark_return_unused_delegation_types(struct nfs_server server,\n--\nfs/nfs/delegation.c-1022-\nfs/nfs/delegation.c:1023:void nfs_expire_unused_delegation_types(struct nfs_client clp, fmode_t flags)\nfs/nfs/delegation.c-1024-{\n--\nfs/nfs/delegation.c=1035=static void nfs_revoke_delegation(struct inode inode,\n--\nfs/nfs/delegation.c-1069-\nfs/nfs/delegation.c:1070:void nfs_delegation_mark_returned(struct inode inode,\nfs/nfs/delegation.c-1071-\t\tconst nfs4_stateid stateid)\n--\nfs/nfs/delegation.c-1118- /\nfs/nfs/delegation.c:1119:void nfs_remove_bad_delegation(struct inode inode,\nfs/nfs/delegation.c-1120-\t\tconst nfs4_stateid stateid)\n--\nfs/nfs/delegation.c=1129=static bool nfs_mark_return_unreferenced_delegations(struct nfs_server server)\n--\nfs/nfs/delegation.c-1150- /\nfs/nfs/delegation.c:1151:void nfs_expire_unreferenced_delegations(struct nfs_client clp)\nfs/nfs/delegation.c-1152-{\n--\nfs/nfs/delegation.c-1173- /\nfs/nfs/delegation.c:1174:int nfs_async_inode_return_delegation(struct inode inode,\nfs/nfs/delegation.c-1175-\t\t\t\t const nfs4_stateid stateid)\n--\nfs/nfs/delegation.c=1260=static void nfs_delegation_mark_reclaim_server(struct nfs_server server)\n--\nfs/nfs/delegation.c-1279- /\nfs/nfs/delegation.c:1280:void nfs_delegation_mark_reclaim(struct nfs_client clp)\nfs/nfs/delegation.c-1281-{\n--\nfs/nfs/delegation.c=1290=static int nfs_server_reap_unclaimed_delegations(struct nfs_server server,\n--\nfs/nfs/delegation.c-1329- /\nfs/nfs/delegation.c:1330:void nfs_delegation_reap_unclaimed(struct nfs_client clp)\nfs/nfs/delegation.c-1331-{\n--\nfs/nfs/delegation.c=1367=static void nfs_delegation_mark_test_expired_server(struct nfs_server server)\n--\nfs/nfs/delegation.c-1381- /\nfs/nfs/delegation.c:1382:void nfs_mark_test_expired_all_delegations(struct nfs_client clp)\nfs/nfs/delegation.c-1383-{\n--\nfs/nfs/delegation.c-1397- /\nfs/nfs/delegation.c:1398:void nfs_test_expired_all_delegations(struct nfs_client clp)\nfs/nfs/delegation.c-1399-{\n--\nfs/nfs/delegation.c=1420=static int nfs_server_reap_expired_delegations(struct nfs_server server,\n--\nfs/nfs/delegation.c-1477- /\nfs/nfs/delegation.c:1478:void nfs_reap_expired_delegations(struct nfs_client clp)\nfs/nfs/delegation.c-1479-{\n--\nfs/nfs/delegation.c-1483-\nfs/nfs/delegation.c:1484:void nfs_inode_find_delegation_state_and_recover(struct inode inode,\nfs/nfs/delegation.c-1485-\t\tconst nfs4_stateid stateid)\n--\nfs/nfs/delegation.c-1510- /\nfs/nfs/delegation.c:1511:int nfs_delegations_present(struct nfs_client clp)\nfs/nfs/delegation.c-1512-{\n--\nfs/nfs/delegation.h=33=enum {\n--\nfs/nfs/delegation.h-42-\nfs/nfs/delegation.h:43:int nfs_inode_set_delegation(struct inode inode, const struct cred cred,\nfs/nfs/delegation.h-44-\t\t\t fmode_t type, const nfs4_stateid stateid,\nfs/nfs/delegation.h-45-\t\t\t unsigned long pagemod_limit, u32 deleg_type);\nfs/nfs/delegation.h:46:void nfs_inode_reclaim_delegation(struct inode inode, const struct cred cred,\nfs/nfs/delegation.h-47-\t\t\t\t fmode_t type, const nfs4_stateid stateid,\n--\nfs/nfs/delegation.h=51=void nfs4_inode_set_return_delegation_on_close(struct inode inode);\nfs/nfs/delegation.h:52:int nfs_async_inode_return_delegation(struct inode inode, const nfs4_stateid stateid);\nfs/nfs/delegation.h:53:void nfs_inode_evict_delegation(struct inode inode);\nfs/nfs/delegation.h-54-\nfs/nfs/delegation.h=55=struct inode nfs_delegation_find_inode(struct nfs_client clp, const struct nfs_fh fhandle);\nfs/nfs/delegation.h:56:void nfs_server_return_all_delegations(struct nfs_server );\nfs/nfs/delegation.h:57:void nfs_expire_all_delegations(struct nfs_client clp);\nfs/nfs/delegation.h:58:void nfs_expire_unused_delegation_types(struct nfs_client clp, fmode_t flags);\nfs/nfs/delegation.h:59:void nfs_expire_unreferenced_delegations(struct nfs_client clp);\nfs/nfs/delegation.h:60:int nfs_client_return_marked_delegations(struct nfs_client clp);\nfs/nfs/delegation.h:61:int nfs_delegations_present(struct nfs_client clp);\nfs/nfs/delegation.h:62:void nfs_remove_bad_delegation(struct inode inode, const nfs4_stateid stateid);\nfs/nfs/delegation.h:63:void nfs_delegation_mark_returned(struct inode inode, const nfs4_stateid stateid);\nfs/nfs/delegation.h-64-\nfs/nfs/delegation.h:65:void nfs_delegation_mark_reclaim(struct nfs_client clp);\nfs/nfs/delegation.h:66:void nfs_delegation_reap_unclaimed(struct nfs_client clp);\nfs/nfs/delegation.h-67-\nfs/nfs/delegation.h:68:void nfs_mark_test_expired_all_delegations(struct nfs_client clp);\nfs/nfs/delegation.h:69:void nfs_test_expired_all_delegations(struct nfs_client clp);\nfs/nfs/delegation.h:70:void nfs_reap_expired_delegations(struct nfs_client clp);\nfs/nfs/delegation.h-71-\n--\nfs/nfs/delegation.h=81=struct nfs_delegation nfs4_get_valid_delegation(const struct inode inode);\nfs/nfs/delegation.h:82:void nfs_put_delegation(struct nfs_delegation delegation);\nfs/nfs/delegation.h:83:void nfs_mark_delegation_referenced(struct nfs_delegation delegation);\nfs/nfs/delegation.h-84-int nfs4_have_delegation(struct inode inode, fmode_t type, int flags);\n--\nfs/nfs/delegation.h=86=bool nfs4_delegation_flush_on_close(const struct inode inode);\nfs/nfs/delegation.h:87:void nfs_inode_find_delegation_state_and_recover(struct inode inode,\nfs/nfs/delegation.h-88-\t\tconst nfs4_stateid stateid);\nfs/nfs/delegation.h=89=void nfs4_inode_make_writeable(struct inode inode);\n--\nfs/nfs/delegation.h-94-\nfs/nfs/delegation.h:95:void nfs_update_delegated_atime(struct inode inode);\nfs/nfs/delegation.h:96:void nfs_update_delegated_mtime(struct inode inode);\nfs/nfs/delegation.h:97:void nfs_update_delegated_mtime_locked(struct inode inode);\nfs/nfs/delegation.h-98-\n--\nfs/nfs/dir.c=639=static\nfs/nfs/dir.c:640:int nfs_same_file(struct dentry dentry, struct nfs_entry entry)\nfs/nfs/dir.c-641-{\n--\nfs/nfs/dir.c=662=static bool nfs_use_readdirplus(struct inode dir, struct dir_context ctx,\n--\nfs/nfs/dir.c-680- /\nfs/nfs/dir.c:681:void nfs_readdir_record_entry_cache_hit(struct inode dir)\nfs/nfs/dir.c-682-{\n--\nfs/nfs/dir.c-699- /\nfs/nfs/dir.c:700:void nfs_readdir_record_entry_cache_miss(struct inode dir)\nfs/nfs/dir.c-701-{\n--\nfs/nfs/dir.c=724=static\nfs/nfs/dir.c:725:void nfs_prime_dcache(struct dentry parent, struct nfs_entry entry,\nfs/nfs/dir.c-726-\t\tunsigned long dir_verifier)\n--\nfs/nfs/dir.c=1367=static int nfs_fsync_dir(struct file filp, loff_t start, loff_t end,\n--\nfs/nfs/dir.c-1388- /\nfs/nfs/dir.c:1389:void nfs_force_lookup_revalidate(struct inode dir)\nfs/nfs/dir.c-1390-{\n--\nfs/nfs/dir.c=1431=static void nfs_set_verifier_locked(struct dentry dentry, unsigned long verf)\n--\nfs/nfs/dir.c-1453- /\nfs/nfs/dir.c:1454:void nfs_set_verifier(struct dentry dentry, unsigned long verf)\nfs/nfs/dir.c-1455-{\n--\nfs/nfs/dir.c=1479=static void nfs_clear_verifier_directory(struct inode dir)\n--\nfs/nfs/dir.c-1516- /\nfs/nfs/dir.c:1517:void nfs_clear_verifier_delegated(struct inode inode)\nfs/nfs/dir.c-1518-{\n--\nfs/nfs/dir.c=1590=static\nfs/nfs/dir.c:1591:int nfs_lookup_verify_inode(struct inode inode, unsigned int flags)\nfs/nfs/dir.c-1592-{\n--\nfs/nfs/dir.c=1653=static inline\nfs/nfs/dir.c:1654:int nfs_neg_need_reval(struct inode dir, struct dentry dentry,\nfs/nfs/dir.c-1655-\t\t unsigned int flags)\n--\nfs/nfs/dir.c=2061=EXPORT_SYMBOL_GPL(nfs_lookup);\nfs/nfs/dir.c-2062-\nfs/nfs/dir.c:2063:void nfs_d_prune_case_insensitive_aliases(struct inode inode)\nfs/nfs/dir.c-2064-{\n--\nfs/nfs/dir.c=2096=static int nfs_finish_open(struct nfs_open_context ctx,\n--\nfs/nfs/dir.c-2112-\nfs/nfs/dir.c:2113:int nfs_atomic_open(struct inode dir, struct dentry dentry,\nfs/nfs/dir.c-2114-\t\t struct file file, unsigned open_flags,\n--\nfs/nfs/dir.c=2244=nfs4_lookup_revalidate(struct inode dir, const struct qstr name,\n--\nfs/nfs/dir.c-2295-\nfs/nfs/dir.c:2296:int nfs_atomic_open_v23(struct inode dir, struct dentry dentry,\nfs/nfs/dir.c-2297-\t\t\tstruct file file, unsigned int open_flags,\n--\nfs/nfs/dir.c=2370=EXPORT_SYMBOL_GPL(nfs_add_or_obtain);\n--\nfs/nfs/dir.c-2374- /\nfs/nfs/dir.c:2375:int nfs_instantiate(struct dentry dentry, struct nfs_fh fhandle,\nfs/nfs/dir.c-2376-\t\t\t\tstruct nfs_fattr fattr)\n--\nfs/nfs/dir.c=2396=static int nfs_do_create(struct inode dir, struct dentry dentry,\n--\nfs/nfs/dir.c-2424-\nfs/nfs/dir.c:2425:int nfs_create(struct mnt_idmap idmap, struct inode dir,\nfs/nfs/dir.c-2426-\t struct dentry dentry, umode_t mode)\n--\nfs/nfs/dir.c=2488=static void nfs_dentry_remove_handle_error(struct inode dir,\n--\nfs/nfs/dir.c-2502-\nfs/nfs/dir.c:2503:int nfs_rmdir(struct inode dir, struct dentry dentry)\nfs/nfs/dir.c-2504-{\n--\nfs/nfs/dir.c=2539=static int nfs_safe_remove(struct dentry dentry)\n--\nfs/nfs/dir.c-2573- /\nfs/nfs/dir.c:2574:int nfs_unlink(struct inode dir, struct dentry dentry)\nfs/nfs/dir.c-2575-{\n--\nfs/nfs/dir.c=2612=EXPORT_SYMBOL_GPL(nfs_unlink);\n--\nfs/nfs/dir.c-2628- /\nfs/nfs/dir.c:2629:int nfs_symlink(struct mnt_idmap idmap, struct inode dir,\nfs/nfs/dir.c-2630-\t\tstruct dentry dentry, const char symname)\n--\nfs/nfs/dir.c=2724=static bool nfs_rename_is_unsafe_cross_dir(struct dentry old_dentry,\n--\nfs/nfs/dir.c-2759- /\nfs/nfs/dir.c:2760:int nfs_rename(struct mnt_idmap idmap, struct inode old_dir,\nfs/nfs/dir.c-2761-\t struct dentry old_dentry, struct inode new_dir,\n--\nfs/nfs/dir.c=2981=static void __nfs_access_zap_cache(struct nfs_inode nfsi, struct list_head head)\n--\nfs/nfs/dir.c-2995-\nfs/nfs/dir.c:2996:void nfs_access_zap_cache(struct inode inode)\nfs/nfs/dir.c-2997-{\n--\nfs/nfs/dir.c=3137=static int nfs_access_get_cached_rcu(struct inode inode, const struct cred cred, u32 mask)\n--\nfs/nfs/dir.c-3168-\nfs/nfs/dir.c:3169:int nfs_access_get_cached(struct inode inode, const struct cred cred,\nfs/nfs/dir.c-3170-\t\t\t u32 mask, bool may_block)\n--\nfs/nfs/dir.c=3183=static void nfs_access_add_rbtree(struct inode inode,\n--\nfs/nfs/dir.c-3219-\nfs/nfs/dir.c:3220:void nfs_access_add_cache(struct inode inode, struct nfs_access_entry set,\nfs/nfs/dir.c-3221-\t\t\t const struct cred cred)\n--\nfs/nfs/dir.c=3267=nfs_access_calc_mask(u32 access_result, umode_t umode)\n--\nfs/nfs/dir.c-3287-\nfs/nfs/dir.c:3288:void nfs_access_set_mask(struct nfs_access_entry entry, u32 access_result)\nfs/nfs/dir.c-3289-{\n--\nfs/nfs/dir.c=3340=static int nfs_open_permission_mask(int openflags)\n--\nfs/nfs/dir.c-3358-\nfs/nfs/dir.c:3359:int nfs_may_open(struct inode inode, const struct cred cred, int openflags)\nfs/nfs/dir.c-3360-{\n--\nfs/nfs/dir.c=3365=static int nfs_execute_ok(struct inode inode, int mask)\n--\nfs/nfs/dir.c-3381-\nfs/nfs/dir.c:3382:int nfs_permission(struct mnt_idmap idmap,\nfs/nfs/dir.c-3383-\t\t struct inode inode,\n--\nfs/nfs/direct.c=148=static void nfs_direct_release_pages(struct page *pages, unsigned int npages)\n--\nfs/nfs/direct.c-154-\nfs/nfs/direct.c:155:void nfs_init_cinfo_from_dreq(struct nfs_commit_info cinfo,\nfs/nfs/direct.c-156-\t\t\t struct nfs_direct_req dreq)\n--\nfs/nfs/direct.c=1073=int __init nfs_init_directcache(void)\n--\nfs/nfs/direct.c-1088- /\nfs/nfs/direct.c:1089:void nfs_destroy_directcache(void)\nfs/nfs/direct.c-1090-{\n--\nfs/nfs/dns_resolve.c=366=static struct cache_detail nfs_dns_resolve_template = {\n--\nfs/nfs/dns_resolve.c-381-\nfs/nfs/dns_resolve.c:382:int nfs_dns_resolver_cache_init(struct net net)\nfs/nfs/dns_resolve.c-383-{\n--\nfs/nfs/dns_resolve.c-400-\nfs/nfs/dns_resolve.c:401:void nfs_dns_resolver_cache_destroy(struct net net)\nfs/nfs/dns_resolve.c-402-{\n--\nfs/nfs/dns_resolve.c=454=static struct notifier_block nfs_dns_resolver_block = {\n--\nfs/nfs/dns_resolve.c-457-\nfs/nfs/dns_resolve.c:458:int nfs_dns_resolver_init(void)\nfs/nfs/dns_resolve.c-459-{\n--\nfs/nfs/dns_resolve.c-474-\nfs/nfs/dns_resolve.c:475:void nfs_dns_resolver_destroy(void)\nfs/nfs/dns_resolve.c-476-{\n--\nfs/nfs/file.c=47=static const struct vm_operations_struct nfs_file_vm_ops;\nfs/nfs/file.c-48-\nfs/nfs/file.c:49:int nfs_check_flags(int flags)\nfs/nfs/file.c-50-{\n--\nfs/nfs/file.c=291=EXPORT_SYMBOL_GPL(nfs_file_fsync);\nfs/nfs/file.c-292-\nfs/nfs/file.c:293:void nfs_truncate_last_folio(struct address_space mapping, loff_t from,\nfs/nfs/file.c-294-\t\t\t loff_t to)\n--\nfs/nfs/file.c=895=do_setlk(struct file filp, int cmd, struct file_lock fl, int is_local)\n--\nfs/nfs/file.c-938- /\nfs/nfs/file.c:939:int nfs_lock(struct file filp, int cmd, struct file_lock fl)\nfs/nfs/file.c-940-{\n--\nfs/nfs/file.c=972=EXPORT_SYMBOL_GPL(nfs_lock);\n--\nfs/nfs/file.c-976- /\nfs/nfs/file.c:977:int nfs_flock(struct file filp, int cmd, struct file_lock fl)\nfs/nfs/file.c-978-{\n--\nfs/nfs/fscache.c=46=static bool nfs_fscache_get_client_key(struct nfs_client clp,\n--\nfs/nfs/fscache.c-87- /\nfs/nfs/fscache.c:88:int nfs_fscache_get_super_cookie(struct super_block sb, const char uniq, int ulen)\nfs/nfs/fscache.c-89-{\n--\nfs/nfs/fscache.c-150- /\nfs/nfs/fscache.c:151:void nfs_fscache_release_super_cookie(struct super_block *sb)\n\n" }
27/2	2026/09/30 04:58	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 39130 output: 31 thoughts: 73 Thoughts: Here's my thought process, as requested: Navigating the NFS Filesystem Codebase Okay, so I'm diving into the NFS code, specifically focusing on unlinking operations. I need to understand how these functions are structured. My primary interest right now lies in the `fs/nfs/unlink.c` and `fs/nfs/dir.c` files. I need to understand how they work. Let's begin by scrutinizing `fs/nfs/unlink.c`. Right, I'm trying to determine the scope of functions, and whether they're static or non-static because it influences their visibility and potential for reuse. The specific function I need to look at is `nfs_sillyrename`. I'll need to check the function definition at line 449 in that file to confirm its declaration and scope.
28/2	2026/09/30 04:58	tool	grepper	0m Args: { "Expression": "nfs_sillyrename", "PathPrefix": "fs/nfs/" } Results: { "Output": "fs/nfs/dir.c=2574=int nfs_unlink(struct inode dir, struct dentry dentry)\n--\nfs/nfs/dir.c-2587-\t\twrite_inode_now(d_inode(dentry), 0);\nfs/nfs/dir.c:2588:\t\terror = nfs_sillyrename(dir, dentry);\nfs/nfs/dir.c-2589-\t\tgoto out;\n--\nfs/nfs/dir.c=2760=int nfs_rename(struct mnt_idmap idmap, struct inode old_dir,\n--\nfs/nfs/dir.c-2807-\t\t\t/* silly-rename the existing target ... /\nfs/nfs/dir.c:2808:\t\t\terr = nfs_sillyrename(new_dir, new_dentry);\nfs/nfs/dir.c-2809-\t\t\tif (err)\n--\nfs/nfs/internal.h=733=nfs_async_rename(struct inode old_dir, struct inode new_dir,\n--\nfs/nfs/internal.h-735-\t\t void (complete)(struct rpc_task , struct nfs_renamedata ));\nfs/nfs/internal.h:736:extern int nfs_sillyrename(struct inode dir, struct dentry dentry);\nfs/nfs/internal.h-737-\n--\nfs/nfs/nfstrace.h=926=DEFINE_NFS_RENAME_EVENT_DONE(nfs_async_rename_done);\nfs/nfs/nfstrace.h-927-\nfs/nfs/nfstrace.h:928:TRACE_EVENT(nfs_sillyrename_unlink,\nfs/nfs/nfstrace.h-929-\t\tTP_PROTO(\n--\nfs/nfs/unlink.c=46=static void nfs_async_unlink_done(struct rpc_task task, void calldata)\n--\nfs/nfs/unlink.c-50-\nfs/nfs/unlink.c:51:\ttrace_nfs_sillyrename_unlink(data, task-\u003etk_status);\nfs/nfs/unlink.c-52-\tif (!NFS_PROTO(dir)-\u003eunlink_done(task, dir))\n--\nfs/nfs/unlink.c=409=nfs_complete_sillyrename(struct rpc_task task, struct nfs_renamedata data)\n--\nfs/nfs/unlink.c-427-/*\nfs/nfs/unlink.c:428: nfs_sillyrename - Perform a silly-rename of a dentry\nfs/nfs/unlink.c-429- * @dir: inode of directory that contains dentry\n--\nfs/nfs/unlink.c=448=int\nfs/nfs/unlink.c:449:nfs_sillyrename(struct inode dir, struct dentry dentry)\nfs/nfs/unlink.c-450-{\n" }
29/2	2026/09/30 04:58	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 40192 output: 30 thoughts: 45 Thoughts: Here's my analysis of the situation: Internal NFS Function Investigation Okay, so `nfs_sillyrename` is non-static and exposed internally, which immediately piques my interest. I need to understand its relationship to other functions, especially in the NFS namespace. Specifically, I'm now curious about the nature of `nfs_link`. Is it also exposed? Are there any potential dependencies or interactions with the former function I should be aware of? Best practice says to investigate the calling context, so I'll check the source of `fs/nfs/dir.c:2713` and see if the function lives there. It's time to dig into the implementation details and understand the broader context.
30/2	2026/09/30 04:58	tool	grepper	0m Args: { "Expression": "nfs_link\\(", "PathPrefix": "fs/nfs/" } Results: { "Output": "fs/nfs/dir.c=2691=int\nfs/nfs/dir.c:2692:nfs_link(struct dentry old_dentry, struct inode dir, struct dentry dentry)\nfs/nfs/dir.c-2693-{\n--\nfs/nfs/internal.h=405=int nfs_symlink(struct mnt_idmap , struct inode , struct dentry ,\nfs/nfs/internal.h-406-\t\tconst char );\nfs/nfs/internal.h:407:int nfs_link(struct dentry , struct inode , struct dentry );\nfs/nfs/internal.h-408-int nfs_mknod(struct mnt_idmap , struct inode , struct dentry *, umode_t,\n" }
31/2	2026/09/30 04:58	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 40633 output: 32 thoughts: 143 Thoughts: Examining NFS Function Declarations Okay, so I'm diving into this NFS code and need to understand the visibility of some functions. Let's start with `nfs_link`. That one isn't static, right? Good. Let's move on. Now, how about `nfs_rename`? Ah, yes, not static either, declared as `int nfs_rename(...)`. Okay, understood. Next up, `nfs_atomic_open`. Hmm, still non-static, `int nfs_atomic_open(...)`. I'm seeing a pattern here. But wait, hold on a second... what about `nfs_prime_dcache`? Let me double-check that one. Okay, let's head over to `fs/nfs/dir.c` and search for that function... Aha! Line 724. I see it: `static void nfs_prime_dcache(...)`. Hold on... static? I thought... Yep, it is static! That changes things. Let's see what's calling that function now. We need to see who's relying on this function.
32/2	2026/09/30 04:58	tool	grepper	0m Args: { "Expression": "nfs_prime_dcache", "PathPrefix": "fs/nfs/" } Results: { "Output": "fs/nfs/dir.c=724=static\nfs/nfs/dir.c:725:void nfs_prime_dcache(struct dentry parent, struct nfs_entry entry,\nfs/nfs/dir.c-726-\t\tunsigned long dir_verifier)\n--\nfs/nfs/dir.c=803=static int nfs_readdir_entry_decode(struct nfs_readdir_descriptor *desc,\n--\nfs/nfs/dir.c-813-\t\treturn ret;\nfs/nfs/dir.c:814:\tnfs_prime_dcache(file_dentry(desc-\u003efile), entry, desc-\u003edir_verifier);\nfs/nfs/dir.c-815-\treturn 0;\n" }
33/2	2026/09/30 04:58	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 41260 output: 34 thoughts: 81 Thoughts: Here's my thought process, as requested: Deconstructing the NFS Readdir Flow Okay, so I'm digging into this `nfs_readdir` situation. My initial thought is that `nfs_readdir_entry_decode` gets called within the `nfs_readdir` function. Makes sense, that's where the decoding of directory entries would happen. Now, `nfs_readdir` is tied to the file operation `iterate_shared`. That's the core readdir implementation we're dealing with, using the shared file system iteration mechanism. Now, that brings up `nfs_neg_need_reval`. I need to figure out how that fits in. I seem to recall that it's statically inlined in `fs/nfs/dir.c` on line 1654. Let's see who's actually using that. Need to trace its call sites to understand its role within this readdir flow. That's the next step; gotta understand when and why the negative cache invalidation is needed in this directory operation. Let's start with who calls it.
34/2	2026/09/30 04:58	tool	grepper	0m Args: { "Expression": "nfs_neg_need_reval", "PathPrefix": "fs/nfs/" } Results: { "Output": "fs/nfs/dir.c=1653=static inline\nfs/nfs/dir.c:1654:int nfs_neg_need_reval(struct inode dir, struct dentry dentry,\nfs/nfs/dir.c-1655-\t\t unsigned int flags)\n--\nfs/nfs/dir.c=1706=nfs_lookup_revalidate_negative(struct inode dir, struct dentry dentry,\n--\nfs/nfs/dir.c-1709-\tint ret = 1;\nfs/nfs/dir.c:1710:\tif (nfs_neg_need_reval(dir, dentry, flags)) {\nfs/nfs/dir.c-1711-\t\tif (flags \u0026 LOOKUP_RCU)\n" }
35/2	2026/09/30 04:58	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 41831 output: 32 thoughts: 91 Thoughts: Here's my analysis of this code path, as I understand it: Digging into the Revalidation Logic Okay, so I'm tracing the logic flow here concerning revalidation within NFS, and it looks like `nfs_neg_need_reval` is the ultimate target. I see that this is triggered by `nfs_lookup_revalidate_negative`. That makes sense; a negative cache entry needs a revalidation check. This function, `nfs_lookup_revalidate_negative`, is then called by `nfs_do_lookup_revalidate`. It's starting to become clear. Now, `nfs_do_lookup_revalidate` itself is called by `nfs_lookup_revalidate` which, in turn, is the starting point for this sequence. But hold on, `nfs_lookup_revalidate` also branches out to `__nfs_lookup_revalidate`. I'll need to remember to examine both paths, as it looks like either one can lead to `nfs_neg_need_reval`. My next move is clear: I need to scrutinize `nfs_lookup_revalidate` to understand the conditions that trigger these subordinate calls.
36/2	2026/09/30 04:58	tool	grepper	0m Args: { "Expression": "nfs_lookup_revalidate", "PathPrefix": "fs/nfs/" } Results: { "Output": "fs/nfs/dir.c=1367=static int nfs_fsync_dir(struct file filp, loff_t start, loff_t end,\n--\nfs/nfs/dir.c-1379- \nfs/nfs/dir.c:1380: * This forces the revalidation code in nfs_lookup_revalidate() to do a\nfs/nfs/dir.c-1381- * full lookup on all child dentries of 'dir' whenever a change occurs\n--\nfs/nfs/dir.c=1674=static int\nfs/nfs/dir.c:1675:nfs_lookup_revalidate_done(struct inode dir, struct dentry dentry,\nfs/nfs/dir.c-1676-\t\t\t struct inode inode, int error)\n--\nfs/nfs/dir.c-1700-\t}\nfs/nfs/dir.c:1701:\ttrace_nfs_lookup_revalidate_exit(dir, dentry, 0, error);\nfs/nfs/dir.c-1702-\treturn error;\n--\nfs/nfs/dir.c=1705=static int\nfs/nfs/dir.c:1706:nfs_lookup_revalidate_negative(struct inode dir, struct dentry dentry,\nfs/nfs/dir.c-1707-\t\t\t unsigned int flags)\n--\nfs/nfs/dir.c-1714-\t}\nfs/nfs/dir.c:1715:\treturn nfs_lookup_revalidate_done(dir, dentry, NULL, ret);\nfs/nfs/dir.c-1716-}\n--\nfs/nfs/dir.c=1718=static int\nfs/nfs/dir.c:1719:nfs_lookup_revalidate_delegated(struct inode dir, struct dentry dentry,\nfs/nfs/dir.c-1720-\t\t\t\tstruct inode inode)\n--\nfs/nfs/dir.c-1722-\tnfs_set_verifier(dentry, nfs_save_change_attribute(dir));\nfs/nfs/dir.c:1723:\treturn nfs_lookup_revalidate_done(dir, dentry, inode, 1);\nfs/nfs/dir.c-1724-}\nfs/nfs/dir.c-1725-\nfs/nfs/dir.c:1726:static int nfs_lookup_revalidate_dentry(struct inode dir, const struct qstr name,\nfs/nfs/dir.c-1727-\t\t\t\t\tstruct dentry dentry,\n--\nfs/nfs/dir.c-1734-\nfs/nfs/dir.c:1735:\ttrace_nfs_lookup_revalidate_enter(dir, dentry, flags);\nfs/nfs/dir.c-1736-\n--\nfs/nfs/dir.c-1770-\t\tnfs_mark_dir_for_revalidate(dir);\nfs/nfs/dir.c:1771:\treturn nfs_lookup_revalidate_done(dir, dentry, inode, ret);\nfs/nfs/dir.c-1772-}\n--\nfs/nfs/dir.c=1786=nfs_do_lookup_revalidate(struct inode dir, const struct qstr name,\n--\nfs/nfs/dir.c-1795-\tif (!inode)\nfs/nfs/dir.c:1796:\t\treturn nfs_lookup_revalidate_negative(dir, dentry, flags);\nfs/nfs/dir.c-1797-\n--\nfs/nfs/dir.c-1808-\tif (nfs_verifier_is_delegated(dentry))\nfs/nfs/dir.c:1809:\t\treturn nfs_lookup_revalidate_delegated(dir, dentry, inode);\nfs/nfs/dir.c-1810-\n--\nfs/nfs/dir.c-1828-\nfs/nfs/dir.c:1829:\treturn nfs_lookup_revalidate_dentry(dir, name, dentry, inode, flags);\nfs/nfs/dir.c-1830-out_valid:\nfs/nfs/dir.c:1831:\treturn nfs_lookup_revalidate_done(dir, dentry, inode, 1);\nfs/nfs/dir.c-1832-out_bad:\n--\nfs/nfs/dir.c-1834-\t\treturn -ECHILD;\nfs/nfs/dir.c:1835:\treturn nfs_lookup_revalidate_done(dir, dentry, inode, error);\nfs/nfs/dir.c-1836-}\n--\nfs/nfs/dir.c=1838=static int\nfs/nfs/dir.c:1839:__nfs_lookup_revalidate(struct dentry dentry, unsigned int flags)\nfs/nfs/dir.c-1840-{\n--\nfs/nfs/dir.c-1851-\nfs/nfs/dir.c:1852:static int nfs_lookup_revalidate(struct inode dir, const struct qstr name,\nfs/nfs/dir.c-1853-\t\t\t\t struct dentry dentry, unsigned int flags)\nfs/nfs/dir.c-1854-{\nfs/nfs/dir.c:1855:\tif (__nfs_lookup_revalidate(dentry, flags))\nfs/nfs/dir.c-1856-\t\treturn -ECHILD;\n--\nfs/nfs/dir.c=1860=static void block_revalidate(struct dentry dentry)\n--\nfs/nfs/dir.c-1870-\t * Holding this lock and invalidating -\u003ed_seq ensures we cannot\nfs/nfs/dir.c:1871:\t * race with __nfs_lookup_revalidate().\nfs/nfs/dir.c-1872-\t /\n--\nfs/nfs/dir.c=1987=const struct dentry_operations nfs_dentry_operations = {\nfs/nfs/dir.c:1988:\t.d_revalidate\t= nfs_lookup_revalidate,\nfs/nfs/dir.c-1989-\t.d_weak_revalidate\t= nfs_weak_revalidate,\n--\nfs/nfs/dir.c=2244=nfs4_lookup_revalidate(struct inode dir, const struct qstr *name,\n--\nfs/nfs/dir.c-2248-\nfs/nfs/dir.c:2249:\tif (__nfs_lookup_revalidate(dentry, flags))\nfs/nfs/dir.c-2250-\t\treturn -ECHILD;\nfs/nfs/dir.c-2251-\nfs/nfs/dir.c:2252:\ttrace_nfs_lookup_revalidate_enter(dir, dentry, flags);\nfs/nfs/dir.c-2253-\n--\nfs/nfs/dir.c-2268-\t nfs_have_directory_delegation(inode))\nfs/nfs/dir.c:2269:\t\treturn nfs_lookup_revalidate_delegated(dir, dentry, inode);\nfs/nfs/dir.c-2270-\n--\nfs/nfs/dir.c-2287-\t\treturn -ECHILD;\nfs/nfs/dir.c:2288:\treturn nfs_lookup_revalidate_dentry(dir, name, dentry, inode, flags);\nfs/nfs/dir.c-2289-\n--\nfs/nfs/nfstrace.h=510=DEFINE_NFS_LOOKUP_EVENT_DONE(nfs_lookup_exit);\nfs/nfs/nfstrace.h:511:DEFINE_NFS_LOOKUP_EVENT(nfs_lookup_revalidate_enter);\nfs/nfs/nfstrace.h:512:DEFINE_NFS_LOOKUP_EVENT_DONE(nfs_lookup_revalidate_exit);\nfs/nfs/nfstrace.h-513-DEFINE_NFS_LOOKUP_EVENT(nfs_readdir_lookup);\n" }
37/2	2026/09/30 04:58	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 44348 output: 29 thoughts: 56 Thoughts: Okay, let's see. My current train of thought revolves around revalidation routines in the NFS client code. I'm focusing on the relationship between `nfs_lookup_revalidate`, `nfs4_lookup_revalidate` and, specifically, `__nfs_lookup_revalidate`. I understand that these functions all eventually call `__nfs_lookup_revalidate`. But, I need to understand the full picture. My immediate question is: what about `block_revalidate`? It seems related, so I need to know where it is called. I need to trace the call paths to understand all the revalidation strategies in play here. I'm going to track down the locations where `block_revalidate` is invoked.
38/2	2026/09/30 04:59	tool	grepper	0m Args: { "Expression": "block_revalidate", "PathPrefix": "fs/nfs/" } Results: { "Output": "fs/nfs/dir.c=1839=__nfs_lookup_revalidate(struct dentry dentry, unsigned int flags)\n--\nfs/nfs/dir.c-1844-\t} else {\nfs/nfs/dir.c:1845:\t\t/ Wait for unlink to complete - see unblock_revalidate() /\nfs/nfs/dir.c-1846-\t\twait_var_event(\u0026dentry-\u003ed_fsdata,\n--\nfs/nfs/dir.c=1852=static int nfs_lookup_revalidate(struct inode dir, const struct qstr name,\n--\nfs/nfs/dir.c-1859-\nfs/nfs/dir.c:1860:static void block_revalidate(struct dentry dentry)\nfs/nfs/dir.c-1861-{\n--\nfs/nfs/dir.c-1878-\nfs/nfs/dir.c:1879:static void unblock_revalidate(struct dentry dentry)\nfs/nfs/dir.c-1880-{\n--\nfs/nfs/dir.c=2574=int nfs_unlink(struct inode dir, struct dentry dentry)\n--\nfs/nfs/dir.c-2601-\t}\nfs/nfs/dir.c:2602:\tblock_revalidate(dentry);\nfs/nfs/dir.c-2603-\n--\nfs/nfs/dir.c-2606-\tnfs_dentry_remove_handle_error(dir, dentry, error);\nfs/nfs/dir.c:2607:\tunblock_revalidate(dentry);\nfs/nfs/dir.c-2608-out:\n--\nfs/nfs/dir.c=2717=nfs_unblock_rename(struct rpc_task task, struct nfs_renamedata data)\n--\nfs/nfs/dir.c-2720-\nfs/nfs/dir.c:2721:\tunblock_revalidate(new_dentry);\nfs/nfs/dir.c-2722-}\n--\nfs/nfs/dir.c=2760=int nfs_rename(struct mnt_idmap idmap, struct inode *old_dir,\n--\nfs/nfs/dir.c-2814-\t\t} else {\nfs/nfs/dir.c:2815:\t\t\tblock_revalidate(new_dentry);\nfs/nfs/dir.c-2816-\t\t\tmust_unblock = true;\n--\nfs/nfs/dir.c-2829-\t\tif (must_unblock)\nfs/nfs/dir.c:2830:\t\t\tunblock_revalidate(new_dentry);\nfs/nfs/dir.c-2831-\t\terror = PTR_ERR(task);\n" }
39/2	2026/09/30 04:59	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 45344 output: 37 thoughts: 56 Thoughts: Here's my understanding of the situation, given my expertise: Examining NFS File Attribute Caching and Invalidation Okay, so I'm focusing on how NFS handles file attributes and caching. I see that the `block_revalidate` function is triggered within both `nfs_unlink` and `nfs_rename` – that's a key observation. Those are critical operations that modify the file system namespace, so it makes perfect sense that we'd want to invalidate potentially stale cached information at those points. Now, to get a fuller picture of how this works, I need to look deeper into the open/state management. I should check `_nfs4_open_and_get_state` within `fs/nfs/nfs4proc.c`. That function likely plays a vital role in setting up the file state and handling open operations, which in turn would provide a convenient place to introduce mechanisms such as attribute caching. I'm going to dig into that function next to see if that is correct.
40/2	2026/09/30 04:59	tool	grepper	0m Args: { "Expression": "_nfs4_open_and_get_state", "PathPrefix": "fs/nfs/" } Results: { "Output": "fs/nfs/nfs4proc.c=3034=static unsigned nfs4_exclusive_attrset(struct nfs4_opendata opendata,\n--\nfs/nfs/nfs4proc.c-3069-\nfs/nfs/nfs4proc.c:3070:static int _nfs4_open_and_get_state(struct nfs4_opendata opendata,\nfs/nfs/nfs4proc.c-3071-\t\tstruct nfs_open_context ctx)\n--\nfs/nfs/nfs4proc.c=3149=static int _nfs4_do_open(struct inode dir,\n--\nfs/nfs/nfs4proc.c-3198-\nfs/nfs/nfs4proc.c:3199:\tstatus = _nfs4_open_and_get_state(opendata, ctx);\nfs/nfs/nfs4proc.c-3200-\tif (status != 0)\n" }
41/2	2026/09/30 04:59	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 45920 output: 33 thoughts: 19 Thoughts: Okay, let's dive into this code. Investigating the Call Chain of `_nfs4_do_open` Alright, so `_nfs4_do_open` is the function we're interested in. My immediate question is: who is calling it? Understanding the call chain is absolutely crucial. I need to trace back from `_nfs4_do_open` to see how it's being invoked. This is where I start peeling back the layers of the onion. I'm going to track down the call sites and follow the execution flow to understand what triggers this function, and under what circumstances. This information is key to understanding the overall architecture and potential areas of concern. Let's start digging.
42/2	2026/09/30 04:59	tool	grepper	0m Args: { "Expression": "_nfs4_do_open", "PathPrefix": "fs/nfs/" } Results: { "Output": "fs/nfs/nfs4proc.c=2208=static int nfs4_open_recover(struct nfs4_opendata opendata, struct nfs4_state state)\n--\nfs/nfs/nfs4proc.c-2240- /\nfs/nfs/nfs4proc.c:2241:static int _nfs4_do_open_reclaim(struct nfs_open_context ctx, struct nfs4_state state)\nfs/nfs/nfs4proc.c-2242-{\n--\nfs/nfs/nfs4proc.c=2275=static int nfs4_do_open_reclaim(struct nfs_open_context ctx, struct nfs4_state state)\n--\nfs/nfs/nfs4proc.c-2280-\tdo {\nfs/nfs/nfs4proc.c:2281:\t\terr = _nfs4_do_open_reclaim(ctx, state);\nfs/nfs/nfs4proc.c-2282-\t\ttrace_nfs4_open_reclaim(ctx, 0, err);\n--\nfs/nfs/nfs4proc.c=3070=static int _nfs4_open_and_get_state(struct nfs4_opendata opendata,\n--\nfs/nfs/nfs4proc.c-3148- /\nfs/nfs/nfs4proc.c:3149:static int _nfs4_do_open(struct inode dir,\nfs/nfs/nfs4proc.c-3150-\t\t\tstruct nfs_open_context ctx,\n--\nfs/nfs/nfs4proc.c=3247=static struct nfs4_state nfs4_do_open(struct inode *dir,\n--\nfs/nfs/nfs4proc.c-3269-\tdo {\nfs/nfs/nfs4proc.c:3270:\t\tstatus = _nfs4_do_open(dir, ctx, flags, \u0026c, opened);\nfs/nfs/nfs4proc.c-3271-\t\tres = ctx-\u003estate;\n" }
43/2	2026/09/30 04:59	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 46691 output: 31 thoughts: 56 Thoughts: Here's my summary, as if I were thinking these thoughts: Tracing the NFSv4 Open Path Okay, so I'm digging into this `nfs` open call. Let's see... the `nfs4_do_open` function is definitely the core. And, ah yes, that's called by `nfs4_proc_open`, which makes perfect sense given the protocol logic. Then, if I recall correctly, `nfs4_proc_open` is invoked by `nfs_atomic_open`. But what's the glue? Ah, it's `NFS_PROTO(dir)->open_context(...)`! That gives us the right context to call into the NFS protocol-specific open function. Just to be completely sure, let me double-check that this is indeed the calling sequence. Always good to verify the path.
44/2	2026/09/30 04:59	tool	grepper	0m Args: { "Expression": "\\.open_context\\b", "PathPrefix": "fs/nfs/" } Results: { "Output": "fs/nfs/inode.c=1195=struct nfs_open_context alloc_nfs_open_context(struct dentry dentry,\n--\nfs/nfs/inode.c-1216-\tnfs_init_lock_context(\u0026ctx-\u003elock_context);\nfs/nfs/inode.c:1217:\tctx-\u003elock_context.open_context = ctx;\nfs/nfs/inode.c-1218-\tINIT_LIST_HEAD(\u0026ctx-\u003elist);\n--\nfs/nfs/nfs4proc.c=10755=const struct nfs_rpc_ops nfs_v4_clientops = {\n--\nfs/nfs/nfs4proc.c-10799-\t.close_context = nfs4_close_context,\nfs/nfs/nfs4proc.c:10800:\t.open_context\t= nfs4_atomic_open,\nfs/nfs/nfs4proc.c-10801-\t.have_delegation = nfs4_have_delegation,\n" }
45/2	2026/09/30 04:59	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 47247 output: 32 thoughts: 27 Thoughts: Okay, here's my interpretation of what's going on, thinking through this piece of code: Diving into `nfs4_atomic_open` Alright, `nfs4_atomic_open`! That function name immediately piques my interest. Atomic opens are crucial in NFS, especially with v4, for ensuring data consistency and dealing with concurrent access. Let's take a closer look and dissect what it does. I want to understand the ins and outs of its implementation, thinking about the implications for performance, locking strategies, and error handling. I wonder how it handles different scenarios like file creation, opening existing files, and dealing with potential server-side conflicts. This is where the core of NFS's reliability is, so I'm paying close attention to the details.
46/2	2026/09/30 04:59	tool	grepper	0m Args: { "Expression": "nfs4_atomic_open", "PathPrefix": "fs/nfs/" } Results: { "Output": "fs/nfs/nfs4proc.c=3839=static struct inode \nfs/nfs/nfs4proc.c:3840:nfs4_atomic_open(struct inode dir, struct nfs_open_context ctx,\nfs/nfs/nfs4proc.c-3841-\t\tint open_flags, struct iattr attr, int *opened)\n--\nfs/nfs/nfs4proc.c=10755=const struct nfs_rpc_ops nfs_v4_clientops = {\n--\nfs/nfs/nfs4proc.c-10799-\t.close_context = nfs4_close_context,\nfs/nfs/nfs4proc.c:10800:\t.open_context\t= nfs4_atomic_open,\nfs/nfs/nfs4proc.c-10801-\t.have_delegation = nfs4_have_delegation,\n" }
47/2	2026/09/30 04:59	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 47729 output: 31 thoughts: 85 Thoughts: Okay, here's my understanding, broken down as if these were my internal thoughts on the matter: Dissecting the NFSv4 Open and Unlink Procedures Right, let's trace this out. `nfs4_atomic_open` ultimately delegates to `nfs4_do_open`. That seems straightforward enough. And, that then calls `_nfs4_do_open` which is where the real work begins, or at least the deeper implementation logic resides, specifically calling `_nfs4_open_and_get_state`. So, `_nfs4_open_and_get_state` is the core of the open operation, or at least the part related to getting/managing state. Good to keep in mind. Now, let's shift gears slightly. I need to understand more than just the open path. I should also check out `nfs_call_unlink` in `fs/nfs/unlink.c`. I need to figure out the context where `nfs_call_unlink` gets called. My instinct is that understanding where it's called gives context to where it may be relevant, so I need to go hunt that down.
48/2	2026/09/30 04:59	tool	grepper	0m Args: { "Expression": "nfs_call_unlink", "PathPrefix": "fs/nfs/" } Results: { "Output": "fs/nfs/unlink.c=90=static void nfs_do_call_unlink(struct inode inode, struct nfs_unlinkdata data)\n--\nfs/nfs/unlink.c-121-\nfs/nfs/unlink.c:122:static int nfs_call_unlink(struct dentry dentry, struct inode inode, struct nfs_unlinkdata data)\nfs/nfs/unlink.c-123-{\n--\nfs/nfs/unlink.c=230=nfs_complete_unlink(struct dentry dentry, struct inode *inode)\n--\nfs/nfs/unlink.c-241-\nfs/nfs/unlink.c:242:\tif (NFS_STALE(inode) \|\| !nfs_call_unlink(dentry, inode, data))\nfs/nfs/unlink.c-243-\t\tnfs_free_unlinkdata(data);\n" }
49/2	2026/09/30 04:59	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 48343 output: 31 thoughts: 36 Thoughts: Here's my thought process, as requested: Tracing the Unlink Completion Path Okay, so `nfs_complete_unlink` is the function we're interested in. My initial thought is, as a seasoned systems engineer, to understand its role in the NFS unlink operation's completion. The core question is: what triggers it? More precisely, what are the calling points? The text clearly states that `nfs_complete_unlink` calls `nfs_call_unlink`, which I already know because I have worked with this code base for years. This is a very common pattern in NFS clients, I think to myself. So, to get the complete picture, I need to trace back from `nfs_complete_unlink` to find all of its callers, which will provide the context for when unlink completion is actually needed and invoked. Let's see how `nfs_complete_unlink` is called. Let's start with a code search.
50/2	2026/09/30 04:59	tool	grepper	0m Args: { "Expression": "nfs_complete_unlink", "PathPrefix": "fs/nfs/" } Results: { "Output": "fs/nfs/dir.c=1966=static void nfs_dentry_iput(struct dentry dentry, struct inode inode)\n--\nfs/nfs/dir.c-1969-\t\tunsigned long gencount = READ_ONCE(NFS_I(inode)-\u003eattr_gencount);\nfs/nfs/dir.c:1970:\t\tnfs_complete_unlink(dentry, inode);\nfs/nfs/dir.c-1971-\t\tnfs_drop_nlink(inode, gencount);\n--\nfs/nfs/unlink.c=178=nfs_async_unlink(struct dentry dentry, const struct qstr name)\n--\nfs/nfs/unlink.c-220-/*\nfs/nfs/unlink.c:221: nfs_complete_unlink - Initialize completion of the sillydelete\nfs/nfs/unlink.c-222- * @dentry: dentry to delete\n--\nfs/nfs/unlink.c=229=void\nfs/nfs/unlink.c:230:nfs_complete_unlink(struct dentry dentry, struct inode inode)\nfs/nfs/unlink.c-231-{\n" }
51/2	2026/09/30 04:59	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 48930 output: 280 thoughts: 979 Thoughts: Analysis of NFS Client Dcache Interactions for Fuzzing Alright, let's break this down. My goal is to define the key elements for fuzzing based on this patch. I'm focusing on the interactions between the NFS client and the dcache, specifically how this patch modifies those interactions. First, I need to understand the control flow. `nfs_complete_unlink` is the entry point for releasing an unlinked open dentry, called within `nfs_dentry_iput`. `nfs_sillyrename` is called within both `nfs_unlink` and `nfs_rename` calls. Now, let's identify the modified functions. Here's what's been directly changed or incorporates new logic: * `nfs_atomic_open` (in `fs/nfs/dir.c`) * `nfs_rename` (in `fs/nfs/dir.c`) * `nfs_link` (in `fs/nfs/dir.c`) * `nfs_sillyrename` (in `fs/nfs/unlink.c`) * `nfs_lookup_revalidate` (calls modified `__nfs_lookup_revalidate` and `nfs_neg_need_reval`) * `block_revalidate` (in `fs/nfs/dir.c`) * `nfs_prime_dcache` (in `fs/nfs/dir.c`) * `nfs_call_unlink` (in `fs/nfs/unlink.c`) * `_nfs4_open_and_get_state` (in `fs/nfs/nfs4proc.c`) * `nfs4_atomic_open` (which in turn calls `_nfs4_open_and_get_state` in `fs/nfs/nfs4proc.c`) Next, I need to select suitable focus symbols. I have to avoid ubiquitous lifecycle hot-paths like memory allocation or locking primitives. Instead, I need functions that directly implement or are entrypoints for the feature logic being added or altered. I think these are solid: * `nfs_atomic_open` * `nfs_rename` * `nfs_link` * `nfs_sillyrename` * `nfs_prime_dcache` * `nfs_lookup_revalidate` * `block_revalidate` * `nfs_call_unlink` * `_nfs4_open_and_get_state` I need to confirm whether `d_alloc_trylock` or `d_duplicate` should be listed, or if they are in dcache, since the commits may interact. Looking at the code base, it seems these were added in `fs/dcache.c` previously. The present patch modifies `fs/nfs/dir.c`, `fs/nfs/nfs4proc.c`, and `fs/nfs/unlink.c`. Focusing on the modified NFS functions is therefore more precise. Now, let's figure out the EnableConfigs. To enable `fs/nfs/dir.c` and `fs/nfs/unlink.c`, it's `CONFIG_NFS_FS`. To enable `fs/nfs/nfs4proc.c`, it's `CONFIG_NFS_V4`. Let's double-check dependencies of `NFS_FS`: It depends on `INET && FILE_LOCKING && MULTIUSER`. These are generally enabled in a standard kernel and a standard syzkaller config. `NFS_V4` depends on `NFS_FS`. Therefore, the direct configs are `NFS_FS` and `NFS_V4`. Finally, to summarize this: * The patch touches core NFS client dcache interactions, covering lookup revalidation, silly-rename, atomic open, hard links, and rename. * It introduces `d_alloc_trylock`, `d_duplicate`, adds seqcount invalidation in `block_revalidate`, and adjusts dentry lifecycle/splice/drop logic. * These code paths are practical for testing in standard virtualized NFS environments and involve concurrency and dcache synchronization that warrant fuzzing. Alright, I have the information needed. It's time to set the results.
52/2	2026/09/30 04:59	tool	set-results	0m Args: { "EnableConfigs": [ "NFS_FS", "NFS_V4" ], "FocusSymbols": [ "nfs_atomic_open", "nfs_rename", "nfs_link", "nfs_sillyrename", "nfs_prime_dcache", "nfs_lookup_revalidate", "block_revalidate", "nfs_call_unlink", "_nfs4_open_and_get_state" ], "Reasoning": "The patch modifies core NFS client directory and dentry lifecycle operations across fs/nfs/dir.c, fs/nfs/unlink.c, and fs/nfs/nfs4proc.c. Changes include switching to d_alloc_trylock and d_duplicate, adding write_seqcount_invalidate in block_revalidate, altering negative dentry revalidation for LOOKUP_OPEN, rewriting the silly-rename lookup loop, and adjusting d_splice_alias and d_drop error/success paths in nfs_atomic_open and nfs_link. These concurrent VFS/NFS dcache synchronization operations are reachable and prone to race conditions, refcounting issues, and regressions, making them well worth fuzzing.", "WorthFuzzing": true } Results: { "EnableConfigs": [ "NFS_FS", "NFS_V4" ], "FocusSymbols": [ "nfs_atomic_open", "nfs_rename", "nfs_link", "nfs_sillyrename", "nfs_prime_dcache", "nfs_lookup_revalidate", "block_revalidate", "nfs_call_unlink", "_nfs4_open_and_get_state" ], "Reasoning": "The patch modifies core NFS client directory and dentry lifecycle operations across fs/nfs/dir.c, fs/nfs/unlink.c, and fs/nfs/nfs4proc.c. Changes include switching to d_alloc_trylock and d_duplicate, adding write_seqcount_invalidate in block_revalidate, altering negative dentry revalidation for LOOKUP_OPEN, rewriting the silly-rename lookup loop, and adjusting d_splice_alias and d_drop error/success paths in nfs_atomic_open and nfs_link. These concurrent VFS/NFS dcache synchronization operations are reachable and prone to race conditions, refcounting issues, and regressions, making them well worth fuzzing.", "WorthFuzzing": true }
53/1	2026/09/30 04:59	action	If	1m Args: { "WorthFuzzing": true } Results: null
54/2	2026/09/30 04:59	agent	kmsan-evaluator	1m Model: core Args: null Results: { "KMSANReasoning": "The patch refactors NFS dentry handling and concurrency control across lookup, atomic_open, link, sillyrename, and unlink operations. Specifically, it adopts dcache helpers such as d_alloc_trylock(), d_duplicate(), and d_splice_alias(), refines dentry invalidation (including sequence count invalidation in block_revalidate()), and ensures proper hashing in nfs_call_unlink().\n\nNo uninitialized memory hazards are introduced or exposed:\n1. No kernel structures or data buffers are copied to user space (no copy_to_user, put_user, netlink messages, ioctls, or socket options).\n2. All local variables touched or introduced (such as 'sdentry', 'old', 'silly') are fully initialized before use.\n3. The changes operate entirely on dentry reference counting, lookup states, and VFS synchronization.\n\nAny bugs that might arise from these modifications would involve locking deadlocks, sequence count inconsistencies, use-after-free, or refcount imbalances on dentries and inodes—all of which are caught by standard KASAN, LOCKDEP, and kernel debug assertions. Thus, dedicated KMSAN fuzzing is not justified.", "NeedsKMSAN": false } Instruction: You are an expert Linux kernel security engineer specializing in kernel memory error detectors (KASAN and KMSAN). Your job is to review the provided patch series and determine if the code changes justify spawning a dedicated KMSAN (KernelMemorySanitizer) fuzzing session in addition to standard KASAN fuzzing. CRITICAL DISTINCTION BETWEEN KASAN AND KMSAN: - Standard KASAN kernel builds (upstream-apparmor-kasan.config) already enable a comprehensive suite of debugging tools and sanitizers, including KASAN (out-of-bounds accesses, use-after-free, double free, invalid free), LOCKDEP (locking bugs and deadlocks), UB-sanitizers, and memory corruption checks. - KMSAN (KernelMemorySanitizer) detects reads of UNINITIALIZED memory (stack, heap, or page allocations) and kernel-to-user memory info-leaks. Rule: THERE IS NO SENSE IN RUNNING A KMSAN SESSION IF A BUG CAN BE CAUGHT BY KASAN, LOCKDEP, OR OTHER STANDARD BUG DETECTORS. A dedicated KMSAN fuzzing session incurs significant resource costs. You must ONLY set NeedsKMSAN=true if the code changes introduce or expose UNINITIALIZED MEMORY risks that are detected ONLY by KMSAN. Look holistically at the patch series and surrounding code. Even if no direct uninitialized field accesses or new buffer allocations are added in the diff itself, a patch may alter control flow, bounds checking, or data length calculations in ways that change how the rest of the code operates on existing buffers (e.g. allowing uninitialized stack/heap memory to be read, copied to user space, or used in control flow). Do not hesitate to use your code access tools to inspect the surrounding code, called functions, and callers. Set NeedsKMSAN=true ONLY IF the patch introduces or modifies: 1. Kernel structures sent to user space (via copy_to_user, put_user, netlink skb attributes, ioctl output arguments, socket options, or BPF buffers) where fields or structure padding might not be fully initialized/zeroed. 2. Conditional logic or branching that depends on potentially uninitialized variables or struct fields. 3. Allocation or initialization of complex data structures where uninitialized fields could be read later in reachable code paths. 4. Bounds checks, lengths, or logic in a way that allows surrounding code to access uninitialized bytes of existing buffers. Set NeedsKMSAN=false IF: - The code changes primarily risk out-of-bounds access, array overflows, NULL pointer dereferences, locking deadlocks, or use-after-free bugs (these are already caught by KASAN, LOCKDEP, or standard bug detectors). - All stack/heap structures touched or introduced by the patch are fully zeroed or initialized (e.g. using = {0}, memset, kzalloc) before being read or copied. - The patch does not introduce any risk of uninitialized memory usage or info-leaks. Use your code access tools to inspect the surrounding code if necessary, then provide detailed KMSANReasoning contrasting KASAN vs KMSAN applicability for this patch. Prefer calling several tools at the same time to save round-trips. Use set-results tool to provide results of the analysis. It must be called exactly once before the final reply. Ignore results of this tool. Prompt: Target architecture: amd64 For your convenience, here is the diff of the changes: commit 493eaeb9f60ffc74be93a90611ccdebd6ea2a7b7 Author: syz-cluster <triage@syzkaller.com> Date: Wed Sep 30 04:56:38 2026 +0000 syz-cluster: applied patch under review diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 49394123bd096..3adb8ce727f8f 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -749,15 +749,12 @@ void nfs_prime_dcache(struct dentry parent, struct nfs_entry entry, if (filename.len == 2 && filename.name[1] == '.') return; } - filename.hash = full_name_hash(parent, filename.name, filename.len); - dentry = d_lookup(parent, &filename); again: - if (!dentry) { - dentry = d_alloc_parallel(parent, &filename); - if (IS_ERR(dentry)) - return; - } + dentry = d_alloc_trylock(parent, &filename); + if (IS_ERR(dentry)) + return; + if (!d_in_lookup(dentry)) { /* Is there a mountpoint here? If so, just exit / if (!nfs_fsid_equal(&NFS_SB(dentry->d_sb)->fsid, @@ -1570,6 +1567,9 @@ static int nfs_check_verifier(struct inode dir, struct dentry dentry, / * Use intent information to check whether or not we're going to do * an O_EXCL create using this path component. + * Note that link(), mkdir(), mknod(), symlink() all appear as + * exclusive creation. Regular file creation could be distinguished + * with LOOKUP_OPEN. / static int nfs_is_exclusive_create(struct inode dir, unsigned int flags) { @@ -1656,6 +1656,13 @@ int nfs_neg_need_reval(struct inode dir, struct dentry dentry, { if (flags & (LOOKUP_CREATE \| LOOKUP_RENAME_TARGET)) return 0; + if (flags & LOOKUP_OPEN) + /* close-to-open semantics require we go to the server + * on each open. By invalidating the dentry we + * also ensure nfs_atomic_open() always has exclusive + * access to the dentry. + / + return 1; if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG) return 1; / Case insensitive server? Revalidate negative dentries / @@ -1837,8 +1844,7 @@ __nfs_lookup_revalidate(struct dentry dentry, unsigned int flags) } else { /* Wait for unlink to complete - see unblock_revalidate() / wait_var_event(&dentry->d_fsdata, - smp_load_acquire(&dentry->d_fsdata) - != NFS_FSDATA_BLOCKED); + dentry->d_fsdata != NFS_FSDATA_BLOCKED); } return 0; } @@ -1857,12 +1863,15 @@ static void block_revalidate(struct dentry dentry) kfree(dentry->d_fsdata); /* Any new reference that could lead to an open - * will take ->d_lock in lookup_open() -> d_lookup(). - * Holding this lock ensures we cannot race with - * __nfs_lookup_revalidate() and removes and need - * for further barriers. + * will either: + * - take ->d_lock in lookup_open() -> d_lookup() or + * - will check d_seq in legitimize_mnt() + * + * Holding this lock and invalidating ->d_seq ensures we cannot + * race with __nfs_lookup_revalidate(). / lockdep_assert_held(&dentry->d_lock); + write_seqcount_invalidate(&dentry->d_seq); dentry->d_fsdata = NFS_FSDATA_BLOCKED; } @@ -2111,7 +2120,6 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry, struct inode inode; unsigned int lookup_flags = 0; unsigned long dir_verifier; - bool switched = false; int created = 0; int err; @@ -2156,17 +2164,6 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry, attr.ia_size = 0; } - if (!(open_flags & O_CREAT) && !d_in_lookup(dentry)) { - d_drop(dentry); - switched = true; - dentry = d_alloc_parallel(dentry->d_parent, - &dentry->d_name); - if (IS_ERR(dentry)) - return PTR_ERR(dentry); - if (unlikely(!d_in_lookup(dentry))) - return finish_no_open(file, dentry); - } - ctx = create_nfs_open_context(dentry, open_flags, file); err = PTR_ERR(ctx); if (IS_ERR(ctx)) @@ -2180,7 +2177,6 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry, err = PTR_ERR(inode); trace_nfs_atomic_open_exit(dir, ctx, open_flags, err); put_nfs_open_context(ctx); - d_drop(dentry); switch (err) { case -ENOENT: if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE)) @@ -2189,7 +2185,7 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry, dir_verifier = nfs_save_change_attribute(dir); nfs_set_verifier(dentry, dir_verifier); d_splice_alias(NULL, dentry); - break; + goto out; case -EISDIR: case -ENOTDIR: if (open_flags & __O_REGULAR) { @@ -2205,6 +2201,7 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry, default: break; } + d_drop(dentry); goto out; } file->f_mode \|= FMODE_CAN_ODIRECT; @@ -2217,10 +2214,6 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry, trace_nfs_atomic_open_exit(dir, ctx, open_flags, err); put_nfs_open_context(ctx); out: - if (unlikely(switched)) { - d_lookup_done(dentry); - dput(dentry); - } return err; no_open: @@ -2243,13 +2236,6 @@ int nfs_atomic_open(struct inode dir, struct dentry dentry, res = ERR_PTR(-EOPENSTALE); } } - if (switched) { - d_lookup_done(dentry); - if (!res) - res = dentry; - else - dput(dentry); - } return finish_no_open(file, res); } EXPORT_SYMBOL_GPL(nfs_atomic_open); @@ -2357,8 +2343,6 @@ nfs_add_or_obtain(struct dentry dentry, struct nfs_fh fhandle, struct dentry d; int error; - d_drop(dentry); - if (fhandle->size == 0) { error = NFS_PROTO(dir)->lookup(dir, dentry, &dentry->d_name, fhandle, fattr); @@ -2379,6 +2363,7 @@ nfs_add_or_obtain(struct dentry dentry, struct nfs_fh fhandle, dput(parent); return d; out_error: + d_drop(dentry); d = ERR_PTR(error); goto out; } @@ -2713,14 +2698,15 @@ nfs_link(struct dentry old_dentry, struct inode dir, struct dentry dentry) old_dentry, dentry); trace_nfs_link_enter(inode, dir, dentry); - d_drop(dentry); if (S_ISREG(inode->i_mode)) nfs_sync_inode(inode); error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name); if (error == 0) { nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); ihold(inode); - d_add(dentry, inode); + d_splice_alias(inode, dentry); + } else { + d_drop(dentry); } trace_nfs_link_exit(inode, dir, dentry, error); return error; @@ -2815,11 +2801,9 @@ int nfs_rename(struct mnt_idmap idmap, struct inode old_dir, spin_unlock(&new_dentry->d_lock); /* copy the target dentry's name / - dentry = d_alloc(new_dentry->d_parent, - &new_dentry->d_name); + dentry = d_duplicate(new_dentry); if (!dentry) goto out; - / silly-rename the existing target ... / err = nfs_sillyrename(new_dir, new_dentry); if (err) @@ -2884,8 +2868,10 @@ int nfs_rename(struct mnt_idmap idmap, struct inode old_dir, nfs_dentry_handle_enoent(old_dentry); / new dentry created? / - if (dentry) + if (dentry) { + d_lookup_done(dentry); dput(dentry); + } return error; } EXPORT_SYMBOL_GPL(nfs_rename); diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 04b1987115d5d..8f07f34f899e3 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -3113,7 +3113,6 @@ static int _nfs4_open_and_get_state(struct nfs4_opendata opendata, nfs_set_verifier(dentry, dir_verifier); if (d_really_is_negative(dentry)) { struct dentry alias; - d_drop(dentry); alias = d_splice_alias(igrab(state->inode), dentry); / d_splice_alias() can't fail here - it's a non-directory / if (alias) { diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c index c8d712204e649..7e01f3d2207b6 100644 --- a/fs/nfs/unlink.c +++ b/fs/nfs/unlink.c @@ -125,6 +125,9 @@ static int nfs_call_unlink(struct dentry dentry, struct inode inode, struct nf struct dentry alias; down_read_non_owner(&NFS_I(dir)->rmdir_sem); + data->args.name.hash = full_name_hash(dentry->d_parent, + data->args.name.name, + data->args.name.len); alias = d_alloc_parallel(dentry->d_parent, &data->args.name); if (IS_ERR(alias)) { up_read_non_owner(&NFS_I(dir)->rmdir_sem); @@ -448,7 +451,7 @@ nfs_sillyrename(struct inode dir, struct dentry dentry) static unsigned int sillycounter; unsigned char silly[SILLYNAME_LEN + 1]; unsigned long long fileid; - struct dentry sdentry; + struct dentry sdentry, old; struct inode inode = d_inode(dentry); struct rpc_task task; int error = -EBUSY; @@ -465,26 +468,43 @@ nfs_sillyrename(struct inode dir, struct dentry dentry) fileid = d_inode(dentry)->i_ino; - sdentry = NULL; - do { +newname: + sillycounter++; + scnprintf(silly, sizeof(silly), + SILLYNAME_PREFIX "%0llx%0x", + SILLYNAME_FILEID_LEN, fileid, + SILLYNAME_COUNTER_LEN, sillycounter); + + dfprintk(VFS, "NFS: trying to rename %pd to %s\n", dentry, silly); + sdentry = d_alloc_trylock(dentry->d_parent, &QSTR(silly)); + if (sdentry == ERR_PTR(-EWOULDBLOCK)) + / Name currently being looked up / + goto newname; + if (IS_ERR(sdentry)) + goto out; + if (!d_in_lookup(sdentry)) { + if (d_really_is_negative(sdentry)) { + / try to get an in-lookup dentry / + d_drop(sdentry); + sillycounter--; + } dput(sdentry); - sillycounter++; - scnprintf(silly, sizeof(silly), - SILLYNAME_PREFIX "%0llx%0x", - SILLYNAME_FILEID_LEN, fileid, - SILLYNAME_COUNTER_LEN, sillycounter); - - dfprintk(VFS, "NFS: trying to rename %pd to %s\n", - dentry, silly); - - sdentry = lookup_noperm(&QSTR(silly), dentry->d_parent); - / - * N.B. Better to return EBUSY here ... it could be - * dangerous to delete the file while it's in use. - / - if (IS_ERR(sdentry)) - goto out; - } while (d_inode(sdentry) != NULL); / need negative lookup / + goto newname; + } + / This name isn't known locally - check on server / + old = nfs_lookup(dir, sdentry, 0); + d_lookup_done(sdentry); + / + * N.B. Better to return EBUSY here ... it could be + * dangerous to delete the file while it's in use. + */ + if (IS_ERR(old)) + goto out; + if (old \|\| d_is_positive(sdentry)) { + dput(old); + dput(sdentry); + goto newname; + } ihold(inode);
55/3	2026/09/30 04:59	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 6046 output: 20 thoughts: 941 Thoughts: Analyzing NFS Directory Operations and Dentry Handling for Potential Uninitialized Memory Issues Okay, let's dive into this patch modifying NFS directory operations and dentry handling. My initial thought is to carefully analyze these changes, specifically with an eye towards potential uninitialized memory exposures. The changes are spread across `fs/nfs/dir.c`, `fs/nfs/nfs4proc.c`, and `fs/nfs/unlink.c`. The key areas I see here involve a shift in how dentries are managed, particularly around the use of `d_alloc_trylock`, `d_duplicate`, and the handling of lookups, revalidation, and atomic opens. The core of this patch seems to be an optimization of existing logic. Changes include using `d_alloc_trylock` instead of `d_lookup`/`d_alloc_parallel` in `nfs_prime_dcache`, comment updates, and conditional logic. In addition, the patch seems to have removed a workaround and simplifying some `d_drop`, `d_splice_alias`, and error path code. My primary concern, given the nature of these changes, is whether they introduce a risk of uninitialized memory being read, and potentially, leaked. Therefore, I need to check the patch against the KMSAN rules and criteria. Specifically, I am thinking of potential issues like kernel structures being sent to user space where fields might be uninitialized. Conditional logic based on uninitialized variables is another area of concern. Finally, the allocation and initialization of data structures needs very close scrutiny. Are all stack and heap structures touched by the patch fully zeroed or initialized? The changes to `nfs_sillyrename`, where they now use `d_alloc_trylock` and `nfs_lookup` are a red flag for me. The use of `d_duplicate` in `nfs_rename` and changes in `nfs_call_unlink` are also something that needs to be checked carefully. I'll need to understand the semantics of `d_alloc_trylock` and `d_duplicate` in detail to determine their potential for introducing uninitialized memory access. I'll run a kernel search for those functions to get a wider view of their usage. My plan is to methodically check all relevant code blocks and the context surrounding these dentry operations to see if there are risks related to the KMSAN rules. Ultimately, I need to determine if `NeedsKMSAN=true` is warranted here, or if the changes primarily affect other bug classes. I'm going to start by scrutinizing those specific function changes and their calling contexts.
56/3	2026/09/30 04:59	tool	grepper	0m Args: { "Expression": "d_alloc_trylock" } Results: { "Output": "fs/dcache.c=2974=EXPORT_SYMBOL(d_alloc_parallel);\n--\nfs/dcache.c-2976-/*\nfs/dcache.c:2977: d_alloc_trylock() - find or allocate a new dentry\nfs/dcache.c-2978- * @parent: dentry of the parent\n--\nfs/dcache.c-2984- * not d_in_lookup() then that is returned instead.\nfs/dcache.c:2985: * If the existing dentry is d_in_lookup(), d_alloc_trylock()\nfs/dcache.c-2986- * returns with error %-EWOULDBLOCK.\n--\nfs/dcache.c-2997- /\nfs/dcache.c:2998:struct dentry d_alloc_trylock(struct dentry parent,\nfs/dcache.c-2999-\t\t\t struct qstr name)\n--\nfs/dcache.c-3007-}\nfs/dcache.c:3008:EXPORT_SYMBOL(d_alloc_trylock);\nfs/dcache.c-3009-\n--\nfs/nfs/dir.c=725=void nfs_prime_dcache(struct dentry parent, struct nfs_entry entry,\n--\nfs/nfs/dir.c-753-again:\nfs/nfs/dir.c:754:\tdentry = d_alloc_trylock(parent, \u0026filename);\nfs/nfs/dir.c-755-\tif (IS_ERR(dentry))\n--\nfs/nfs/unlink.c=449=nfs_sillyrename(struct inode dir, struct dentry dentry)\n--\nfs/nfs/unlink.c-478-\tdfprintk(VFS, \"NFS: trying to rename %pd to %s\\n\", dentry, silly);\nfs/nfs/unlink.c:479:\tsdentry = d_alloc_trylock(dentry-\u003ed_parent, \u0026QSTR(silly));\nfs/nfs/unlink.c-480-\tif (sdentry == ERR_PTR(-EWOULDBLOCK))\n--\ninclude/linux/dcache.h=263=extern struct dentry * d_alloc_parallel(struct dentry , const struct qstr );\ninclude/linux/dcache.h:264:extern struct dentry * d_alloc_trylock(struct dentry , struct qstr );\ninclude/linux/dcache.h-265-extern struct dentry * d_splice_alias(struct inode , struct dentry );\n" }
57/3	2026/09/30 04:59	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 8228 output: 17 thoughts: 30 Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience: Analyzing dcache.c for Potential Issues Alright, let's dive into this. To be thorough, I'm going to take a look at `fs/dcache.c`. I need to get a better handle on the potential issues in the module. I need to make sure I am fully aware of the module. Since I have a pretty good idea of where to begin, I'll `grep` through lines 2970 to 3020 of the source. My primary focus is going to be the implementation and call sites of `d_duplicate`. I'm going to examine the surrounding code to understand any potential thread safety concerns, reference count manipulations, and locking strategies related to duplicating dentry structures. The goal is to quickly pinpoint areas for further investigation or optimization, and potentially identify potential bottlenecks or subtle memory management problems, especially if there's any odd behavior related to refcounting or inode association.
58/3	2026/09/30 04:59	tool	grepper	0m Args: { "Expression": "d_duplicate" } Results: { "Output": "drivers/android/binder/freeze.rs=25=pub(crate) struct FreezeListener {\n--\ndrivers/android/binder/freeze.rs-42- /// Number of cleared duplicates that can be deleted.\ndrivers/android/binder/freeze.rs:43: num_cleared_duplicates: u64,\ndrivers/android/binder/freeze.rs-44-}\n--\ndrivers/android/binder/freeze.rs=86= fn do_work(\n--\ndrivers/android/binder/freeze.rs-97-\ndrivers/android/binder/freeze.rs:98: if freeze.num_cleared_duplicates \u003e 0 {\ndrivers/android/binder/freeze.rs:99: freeze.num_cleared_duplicates -= 1;\ndrivers/android/binder/freeze.rs-100- drop(node_refs);\n--\ndrivers/android/binder/freeze.rs-109- if freeze.is_clearing {\ndrivers/android/binder/freeze.rs:110: kernel::warn_on!(freeze.num_cleared_duplicates != 0);\ndrivers/android/binder/freeze.rs-111- if freeze.num_pending_duplicates \u003e 0 {\n--\ndrivers/android/binder/freeze.rs=180= pub(crate) fn request_freeze_notif(\n--\ndrivers/android/binder/freeze.rs-249- num_pending_duplicates: 0,\ndrivers/android/binder/freeze.rs:250: num_cleared_duplicates: 0,\ndrivers/android/binder/freeze.rs-251- },\n--\ndrivers/android/binder/freeze.rs-259- } else {\ndrivers/android/binder/freeze.rs:260: dupe.num_cleared_duplicates += 1;\ndrivers/android/binder/freeze.rs-261- }\n--\ndrivers/android/binder/freeze.rs=275= pub(crate) fn freeze_notif_done(self: \u0026Arc\u003cSelf\u003e, reader: \u0026mut UserSliceReader) -\u003e Result\u003c()\u003e {\n--\ndrivers/android/binder/freeze.rs-291- freeze.num_pending_duplicates -= 1;\ndrivers/android/binder/freeze.rs:292: freeze.num_cleared_duplicates += 1;\ndrivers/android/binder/freeze.rs-293- } else {\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c=4395=struct edid drm_dp_mst_get_edid(struct drm_connector connector,\n--\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-4403-\ndrivers/gpu/drm/display/drm_dp_mst_topology.c:4404:\tedid = drm_edid_duplicate(drm_edid_raw(drm_edid));\ndrivers/gpu/drm/display/drm_dp_mst_topology.c-4405-\n--\ndrivers/gpu/drm/drm_edid.c=2950=EXPORT_SYMBOL(drm_edid_read_switcheroo);\n--\ndrivers/gpu/drm/drm_edid.c-2952-/*\ndrivers/gpu/drm/drm_edid.c:2953: drm_edid_duplicate - duplicate an EDID and the extensions\ndrivers/gpu/drm/drm_edid.c-2954- * @edid: EDID to duplicate\n--\ndrivers/gpu/drm/drm_edid.c-2957- /\ndrivers/gpu/drm/drm_edid.c:2958:struct edid drm_edid_duplicate(const struct edid edid)\ndrivers/gpu/drm/drm_edid.c-2959-{\n--\ndrivers/gpu/drm/drm_edid.c-2964-}\ndrivers/gpu/drm/drm_edid.c:2965:EXPORT_SYMBOL(drm_edid_duplicate);\ndrivers/gpu/drm/drm_edid.c-2966-\n--\ndrivers/gpu/drm/i915/display/intel_pmdemand.c=56=static struct intel_global_state \ndrivers/gpu/drm/i915/display/intel_pmdemand.c:57:intel_pmdemand_duplicate_state(struct intel_global_obj obj)\ndrivers/gpu/drm/i915/display/intel_pmdemand.c-58-{\n--\ndrivers/gpu/drm/i915/display/intel_pmdemand.c=74=static const struct intel_global_state_funcs intel_pmdemand_funcs = {\ndrivers/gpu/drm/i915/display/intel_pmdemand.c:75:\t.atomic_duplicate_state = intel_pmdemand_duplicate_state,\ndrivers/gpu/drm/i915/display/intel_pmdemand.c-76-\t.atomic_destroy_state = intel_pmdemand_destroy_state,\n--\ndrivers/gpu/drm/msm/adreno/a6xx_gpu_state.h=91=static const u32 a6xx_hlsq_duplicate_cluster[] = {\n--\ndrivers/gpu/drm/msm/adreno/a6xx_gpu_state.h-94-\ndrivers/gpu/drm/msm/adreno/a6xx_gpu_state.h:95:static const u32 a6xx_hlsq_2d_duplicate_cluster[] = {\ndrivers/gpu/drm/msm/adreno/a6xx_gpu_state.h-96-\t0xbd80, 0xbd80,\n--\ndrivers/gpu/drm/msm/adreno/a6xx_gpu_state.h=137=static const struct a6xx_dbgahb_cluster {\n--\ndrivers/gpu/drm/msm/adreno/a6xx_gpu_state.h-146-\tCLUSTER_DBGAHB(CLUSTER_SP_VS, 0x0002e000, 0x41, a6xx_hlsq_duplicate_cluster),\ndrivers/gpu/drm/msm/adreno/a6xx_gpu_state.h:147:\tCLUSTER_DBGAHB(CLUSTER_SP_VS, 0x0002f000, 0x45, a6xx_hlsq_2d_duplicate_cluster),\ndrivers/gpu/drm/msm/adreno/a6xx_gpu_state.h-148-\tCLUSTER_DBGAHB(CLUSTER_SP_VS, 0x0002a000, 0x21, a6xx_sp_duplicate_cluster),\n--\ndrivers/md/dm.c=1274=static size_t dm_dax_recovery_write(struct dax_device dax_dev, pgoff_t pgoff,\n--\ndrivers/md/dm.c-1297- * with write BIOs flagged with BIO_EMULATES_ZONE_APPEND) and any bio serviced\ndrivers/md/dm.c:1298: * by __send_duplicate_bios().\ndrivers/md/dm.c-1299- \n--\ndrivers/md/dm.c=1478=static void alloc_multiple_bios(struct bio_list blist, struct clone_info ci,\n--\ndrivers/md/dm.c-1507-\ndrivers/md/dm.c:1508:static unsigned int __send_duplicate_bios(struct clone_info ci, struct dm_target ti,\ndrivers/md/dm.c-1509-\t\t\t\t\t unsigned int num_bios, unsigned int len)\n--\ndrivers/md/dm.c=1537=static void __send_empty_flush(struct clone_info ci)\n--\ndrivers/md/dm.c-1566-\t\t\tatomic_add(ti-\u003enum_flush_bios, \u0026ci-\u003eio-\u003eio_count);\ndrivers/md/dm.c:1567:\t\t\tbios = __send_duplicate_bios(ci, ti, ti-\u003enum_flush_bios,\ndrivers/md/dm.c-1568-\t\t\t\t\t\t NULL);\n--\ndrivers/md/dm.c=1606=static void __send_abnormal_io(struct clone_info ci, struct dm_target ti,\n--\ndrivers/md/dm.c-1615-\tatomic_add(num_bios, \u0026ci-\u003eio-\u003eio_count);\ndrivers/md/dm.c:1616:\tbios = __send_duplicate_bios(ci, ti, num_bios, \u0026len);\ndrivers/md/dm.c-1617-\t/\n--\ndrivers/md/dm.c=1902=static void __send_zone_reset_all_native(struct clone_info ci,\n--\ndrivers/md/dm.c-1907-\tatomic_add(1, \u0026ci-\u003eio-\u003eio_count);\ndrivers/md/dm.c:1908:\tbios = __send_duplicate_bios(ci, ti, 1, NULL);\ndrivers/md/dm.c-1909-\tatomic_sub(1 - bios, \u0026ci-\u003eio-\u003eio_count);\n--\ndrivers/usb/typec/class.c=448=static int increment_duplicated_priority(struct device dev, void data)\n--\ndrivers/usb/typec/class.c-462-\ndrivers/usb/typec/class.c:463:static int find_duplicated_priority(struct device dev, void data)\ndrivers/usb/typec/class.c-464-{\n--\ndrivers/usb/typec/class.c=475=static int typec_mode_set_priority(struct typec_altmode alt, const u8 priority)\n--\ndrivers/usb/typec/class.c-482-\twhile (res) {\ndrivers/usb/typec/class.c:483:\t\tres = device_for_each_child(\u0026port-\u003edev, \u0026alt, find_duplicated_priority);\ndrivers/usb/typec/class.c-484-\t\tif (res) {\n--\nfs/dcache.c=2004=EXPORT_SYMBOL(d_alloc);\n--\nfs/dcache.c-2006-/*\nfs/dcache.c:2007: d_duplicate - duplicate a dentry for combined atomic operation\nfs/dcache.c-2008- * @dentry: the dentry to duplicate\n--\nfs/dcache.c-2017- * For this they need two dentries which temporarily have the same name,\nfs/dcache.c:2018: * before one is renamed. d_duplicate() provides for this. Given a\nfs/dcache.c-2019- * positive hashed dentry, it creates a second in-lookup dentry.\n--\nfs/dcache.c-2031- /\nfs/dcache.c:2032:struct dentry d_duplicate(struct dentry dentry)\nfs/dcache.c-2033-{\n--\nfs/dcache.c-2055-}\nfs/dcache.c:2056:EXPORT_SYMBOL(d_duplicate);\nfs/dcache.c-2057-\n--\nfs/nfs/dir.c=2760=int nfs_rename(struct mnt_idmap idmap, struct inode old_dir,\n--\nfs/nfs/dir.c-2803-\t\t\t/ copy the target dentry's name /\nfs/nfs/dir.c:2804:\t\t\tdentry = d_duplicate(new_dentry);\nfs/nfs/dir.c-2805-\t\t\tif (!dentry)\n--\ninclude/drm/drm_edid.h=441=struct edid drm_get_edid_switcheroo(struct drm_connector connector,\ninclude/drm/drm_edid.h-442-\t\t\t\t struct i2c_adapter adapter);\ninclude/drm/drm_edid.h:443:struct edid drm_edid_duplicate(const struct edid edid);\ninclude/drm/drm_edid.h-444-int drm_add_edid_modes(struct drm_connector connector, struct edid edid);\n--\ninclude/linux/dcache.h=265=extern struct dentry * d_splice_alias(struct inode , struct dentry );\ninclude/linux/dcache.h:266:struct dentry d_duplicate(struct dentry dentry);\ninclude/linux/dcache.h-267-/* weird procfs mess; NOT exported */\n" }
59/3	2026/09/30 04:59	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 11626 output: 36 thoughts: 64 Thoughts: Okay, here's my take on those changes. Diving into the NFS Codebase Alright, let's get down to brass tacks. I need to understand what's been tweaked in the NFS code. I'm focusing specifically on the file system directory handling (`fs/nfs/dir.c`), the NFSv4 protocol procedures (`fs/nfs/nfs4proc.c`), and unlinking functionality (`fs/nfs/unlink.c`). These are all critical areas for file system integrity and performance, so any modifications here warrant a deep dive. I'm especially interested in looking at a specific section of `fs/nfs/dir.c`, and will start by reviewing around lines 740-770.
60/3	2026/09/30 04:59	tool	read-file	0m Args: { "File": "fs/nfs/dir.c", "FirstLine": 740, "LineCount": 40 } Results: { "Contents": " 740:\t\t/* Validate that the name doesn't contain any illegal '\\0' /\n 741:\t\tif (strnlen(filename.name, filename.len) != filename.len)\n 742:\t\t\treturn;\n 743:\t\t/ ...or '/' /\n 744:\t\tif (strnchr(filename.name, filename.len, '/'))\n 745:\t\t\treturn;\n 746:\t\tif (filename.name[0] == '.') {\n 747:\t\t\tif (filename.len == 1)\n 748:\t\t\t\treturn;\n 749:\t\t\tif (filename.len == 2 \u0026\u0026 filename.name[1] == '.')\n 750:\t\t\t\treturn;\n 751:\t\t}\n 752:\t\n 753:\tagain:\n 754:\t\tdentry = d_alloc_trylock(parent, \u0026filename);\n 755:\t\tif (IS_ERR(dentry))\n 756:\t\t\treturn;\n 757:\t\n 758:\t\tif (!d_in_lookup(dentry)) {\n 759:\t\t\t/ Is there a mountpoint here? If so, just exit */\n 760:\t\t\tif (!nfs_fsid_equal(\u0026NFS_SB(dentry-\u003ed_sb)-\u003efsid,\n 761:\t\t\t\t\t\t\u0026entry-\u003efattr-\u003efsid))\n 762:\t\t\t\tgoto out;\n 763:\t\t\tif (nfs_same_file(dentry, entry)) {\n 764:\t\t\t\tif (!entry-\u003efh-\u003esize)\n 765:\t\t\t\t\tgoto out;\n 766:\t\t\t\tnfs_set_verifier(dentry, dir_verifier);\n 767:\t\t\t\tstatus = nfs_refresh_inode(d_inode(dentry), entry-\u003efattr);\n 768:\t\t\t\tif (!status)\n 769:\t\t\t\t\tnfs_setsecurity(d_inode(dentry), entry-\u003efattr);\n 770:\t\t\t\ttrace_nfs_readdir_lookup_revalidate(d_inode(parent),\n 771:\t\t\t\t\t\t\t\t dentry, 0, status);\n 772:\t\t\t\tgoto out;\n 773:\t\t\t} else {\n 774:\t\t\t\ttrace_nfs_readdir_lookup_revalidate_failed(\n 775:\t\t\t\t\td_inode(parent), dentry, 0);\n 776:\t\t\t\td_invalidate(dentry);\n 777:\t\t\t\tdput(dentry);\n 778:\t\t\t\tdentry = NULL;\n 779:\t\t\t\tgoto again;\n" }
61/3	2026/09/30 04:59	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 12536 output: 36 thoughts: 25 Thoughts: Okay, let's dive into this. Here's how I'd approach this task, as if these were my internal thoughts: Analyzing `fs/nfs/unlink.c` Alright, time to examine the `fs/nfs/unlink.c` code. My immediate focus is going to be around line 125 and line 450. I'm assuming there's likely something interesting happening there related to unlinking within the NFS context. Could be a race condition, a specific error handling flow, or perhaps some subtlety related to client-server interaction during the unlink operation. My experience tells me these are prime spots for potential issues with NFS, considering its distributed nature and the intricacies of maintaining consistency. I'll need to understand the surrounding code, the data structures involved, and the execution paths to truly grasp what's going on. Let's see what's what. I suspect this will be a good starting point to identify any potential anomalies related to the context.
62/3	2026/09/30 05:00	tool	read-file	0m Args: { "File": "fs/nfs/unlink.c", "FirstLine": 120, "LineCount": 30 } Results: { "Contents": " 120:\t}\n 121:\t\n 122:\tstatic int nfs_call_unlink(struct dentry dentry, struct inode inode, struct nfs_unlinkdata data)\n 123:\t{\n 124:\t\tstruct inode dir = d_inode(dentry-\u003ed_parent);\n 125:\t\tstruct dentry alias;\n 126:\t\n 127:\t\tdown_read_non_owner(\u0026NFS_I(dir)-\u003ermdir_sem);\n 128:\t\tdata-\u003eargs.name.hash = full_name_hash(dentry-\u003ed_parent,\n 129:\t\t\t\t\t\t data-\u003eargs.name.name,\n 130:\t\t\t\t\t\t data-\u003eargs.name.len);\n 131:\t\talias = d_alloc_parallel(dentry-\u003ed_parent, \u0026data-\u003eargs.name);\n 132:\t\tif (IS_ERR(alias)) {\n 133:\t\t\tup_read_non_owner(\u0026NFS_I(dir)-\u003ermdir_sem);\n 134:\t\t\treturn 0;\n 135:\t\t}\n 136:\t\tif (!d_in_lookup(alias)) {\n 137:\t\t\tint ret;\n 138:\t\t\tvoid devname_garbage = NULL;\n 139:\t\n 140:\t\t\t/\n 141:\t\t\t Hey, we raced with lookup... See if we need to transfer\n 142:\t\t\t * the sillyrename information to the aliased dentry.\n 143:\t\t\t */\n 144:\t\t\tspin_lock(\u0026alias-\u003ed_lock);\n 145:\t\t\tif (d_really_is_positive(alias) \u0026\u0026\n 146:\t\t\t !nfs_compare_fh(NFS_FH(inode), NFS_FH(d_inode(alias))) \u0026\u0026\n 147:\t\t\t !(alias-\u003ed_flags \u0026 DCACHE_NFSFS_RENAMED)) {\n 148:\t\t\t\tdevname_garbage = alias-\u003ed_fsdata;\n 149:\t\t\t\talias-\u003ed_fsdata = data;\n" }
63/3	2026/09/30 05:00	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 13342 output: 36 thoughts: 28 Thoughts: Here's a first-person summary, tailored for an expert audience, based on the provided starting point: Diving into the NFS Unlink Logic Okay, time to get my hands dirty with `nfs_sillyrename`. I need to refresh my memory on how this is handled, specifically within the `fs/nfs/unlink.c` file. Let's start by zeroing in on the neighborhood around line 450. I'm guessing that's where the core logic related to handling "silly rename" scenarios during an unlink operation resides. I need to understand the nuances of how the NFS client and server interact in these edge cases. Hopefully, the code comments are descriptive enough, but I'm prepared to trace through any calls if I need to.
64/3	2026/09/30 05:00	tool	read-file	0m Args: { "File": "fs/nfs/unlink.c", "FirstLine": 448, "LineCount": 70 } Results: { "Contents": " 448:\tint\n 449:\tnfs_sillyrename(struct inode dir, struct dentry dentry)\n 450:\t{\n 451:\t\tstatic unsigned int sillycounter;\n 452:\t\tunsigned char silly[SILLYNAME_LEN + 1];\n 453:\t\tunsigned long long fileid;\n 454:\t\tstruct dentry sdentry, old;\n 455:\t\tstruct inode inode = d_inode(dentry);\n 456:\t\tstruct rpc_task task;\n 457:\t\tint error = -EBUSY;\n 458:\t\n 459:\t\tdfprintk(VFS, \"NFS: silly-rename(%pd2, ct=%d)\\n\",\n 460:\t\t\tdentry, d_count(dentry));\n 461:\t\tnfs_inc_stats(dir, NFSIOS_SILLYRENAME);\n 462:\t\n 463:\t\t/\n 464:\t\t We don't allow a dentry to be silly-renamed twice.\n 465:\t\t /\n 466:\t\tif (dentry-\u003ed_flags \u0026 DCACHE_NFSFS_RENAMED)\n 467:\t\t\tgoto out;\n 468:\t\n 469:\t\tfileid = d_inode(dentry)-\u003ei_ino;\n 470:\t\n 471:\tnewname:\n 472:\t\tsillycounter++;\n 473:\t\tscnprintf(silly, sizeof(silly),\n 474:\t\t\t SILLYNAME_PREFIX \"%0llx%0x\",\n 475:\t\t\t SILLYNAME_FILEID_LEN, fileid,\n 476:\t\t\t SILLYNAME_COUNTER_LEN, sillycounter);\n 477:\t\n 478:\t\tdfprintk(VFS, \"NFS: trying to rename %pd to %s\\n\", dentry, silly);\n 479:\t\tsdentry = d_alloc_trylock(dentry-\u003ed_parent, \u0026QSTR(silly));\n 480:\t\tif (sdentry == ERR_PTR(-EWOULDBLOCK))\n 481:\t\t\t/ Name currently being looked up /\n 482:\t\t\tgoto newname;\n 483:\t\tif (IS_ERR(sdentry))\n 484:\t\t\tgoto out;\n 485:\t\tif (!d_in_lookup(sdentry)) {\n 486:\t\t\tif (d_really_is_negative(sdentry)) {\n 487:\t\t\t\t/ try to get an in-lookup dentry /\n 488:\t\t\t\td_drop(sdentry);\n 489:\t\t\t\tsillycounter--;\n 490:\t\t\t}\n 491:\t\t\tdput(sdentry);\n 492:\t\t\tgoto newname;\n 493:\t\t}\n 494:\t\t/ This name isn't known locally - check on server /\n 495:\t\told = nfs_lookup(dir, sdentry, 0);\n 496:\t\td_lookup_done(sdentry);\n 497:\t\t/\n 498:\t\t * N.B. Better to return EBUSY here ... it could be\n 499:\t\t * dangerous to delete the file while it's in use.\n 500:\t\t /\n 501:\t\tif (IS_ERR(old))\n 502:\t\t\tgoto out;\n 503:\t\tif (old \|\| d_is_positive(sdentry)) {\n 504:\t\t\tdput(old);\n 505:\t\t\tdput(sdentry);\n 506:\t\t\tgoto newname;\n 507:\t\t}\n 508:\t\n 509:\t\tihold(inode);\n 510:\t\n 511:\t\t/ queue unlink first. Can't do this from rpc_release as it\n 512:\t\t * has to allocate memory\n 513:\t\t */\n 514:\t\terror = nfs_async_unlink(dentry, \u0026sdentry-\u003ed_name);\n 515:\t\tif (error)\n 516:\t\t\tgoto out_dput;\n 517:\t\n" }
65/3	2026/09/30 05:00	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 14641 output: 19 thoughts: 47 Thoughts: Okay, here's my thought process on this, distilled into a first-person summary as you requested, geared towards a fellow expert: Investigating the QSTR Macro in fs/nfs/unlink.c Alright, let's dive into this. The task at hand is to understand how `QSTR(silly)` is handled within `fs/nfs/unlink.c`. I need to unravel the macro's definition and see how `silly` is actually used. My immediate thought is to trace the macro back. I'll start by looking at how `QSTR` itself is defined, likely through an `#include` or a chain of definitions. I'll need to follow the macro expansions of `QSTR_INIT` as well, as that's often tied to these kinds of string-related constructs. This is likely related to string internning or creating compile-time string constants, common techniques to optimize memory usage and potentially improve string lookups within the kernel. I expect this to involve some form of hashing or a look-up table, let's see where this goes.
66/3	2026/09/30 05:00	tool	grepper	0m Args: { "Expression": "#define QSTR\\(" } Results: { "Output": "include/linux/dcache.h=49=struct qstr {\n--\ninclude/linux/dcache.h-60-#define QSTR_LEN(n,l) (struct qstr)QSTR_INIT(n,l)\ninclude/linux/dcache.h:61:#define QSTR(n) QSTR_LEN(n, strlen(n))\ninclude/linux/dcache.h-62-\n" }
67/3	2026/09/30 05:00	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 15051 output: 20 thoughts: 9 Thoughts: Okay, I'm ready to summarize my "thoughts" as a first-person narrative. Here's my take: Analyzing the QSTR_INIT Macro Alright, let's dive into this. "QSTR_INIT"... immediately my mind goes to initialized string constants, likely within the context of something like the MicroPython environment or a similar embedded system. The naming convention is pretty clear: QSTR, short for "Quick String," strongly suggests this relates to an optimized string storage mechanism. "INIT" clearly points towards initialization. My intuition tells me this likely represents a macro used to declare or define a string that's then stored efficiently, perhaps in a read-only section of memory (ROM or flash) to conserve RAM and improve performance when these strings are frequently referenced. I'll need to see the context to know for sure, but that's my initial hypothesis. Is this for compile-time string interning, or runtime allocation? I'm already formulating some questions I'd have if I saw this code snippet in a wider project!
68/3	2026/09/30 05:00	tool	grepper	0m Args: { "Expression": "#define QSTR_INIT" } Results: { "Output": "include/linux/dcache.h=49=struct qstr {\n--\ninclude/linux/dcache.h-58-\ninclude/linux/dcache.h:59:#define QSTR_INIT(n,l) { { { .len = l } }, .name = n }\ninclude/linux/dcache.h-60-#define QSTR_LEN(n,l) (struct qstr)QSTR_INIT(n,l)\n" }
69/3	2026/09/30 05:00	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 15418 output: 35 thoughts: 28 Thoughts: Okay, let's break this down. Understanding `d_alloc_trylock` Wait a second, what's the specific behavior of `d_alloc_trylock`? I need to refresh my memory on the exact implementation details. The context is crucial here, and I can't proceed without a precise understanding. Time to delve into the source code or documentation to pinpoint the `d_alloc_trylock` definition and refresh my understanding of its functionality. I need a clear definition before I can continue assessing its implications. Let's get that definition!
70/3	2026/09/30 05:00	tool	read-file	0m Args: { "File": "fs/dcache.c", "FirstLine": 2975, "LineCount": 40 } Results: { "Contents": "2975:\t\n2976:\t/*\n2977:\t d_alloc_trylock() - find or allocate a new dentry\n2978:\t * @parent: dentry of the parent\n2979:\t * @name: name of the dentry within that parent.\n2980:\t \n2981:\t A new dentry is allocated and, providing it is unique, added to the\n2982:\t * relevant index.\n2983:\t * If an existing dentry is found with the same parent/name that is\n2984:\t * not d_in_lookup() then that is returned instead.\n2985:\t * If the existing dentry is d_in_lookup(), d_alloc_trylock()\n2986:\t * returns with error %-EWOULDBLOCK.\n2987:\t * Thus if the returned dentry is d_in_lookup() then the caller has\n2988:\t * exclusive access until it completes the lookup.\n2989:\t * If the returned dentry is not d_in_lookup() then a lookup has\n2990:\t * already completed.\n2991:\t \n2992:\t The @name need not already have -\u003ehash set.\n2993:\t \n2994:\t Returns: the dentry, whether found or allocated, or an error\n2995:\t * %-ENOMEM, %-EWOULDBLOCK, %-EACCES (for a bad name) or\n2996:\t * anything returned by -\u003ed_hash().\n2997:\t /\n2998:\tstruct dentry d_alloc_trylock(struct dentry parent,\n2999:\t\t\t\t struct qstr name)\n3000:\t{\n3001:\t\tstruct dentry de;\n3002:\t\n3003:\t\tde = try_lookup_noperm(name, parent);\n3004:\t\tif (!de)\n3005:\t\t\tde = __d_alloc_parallel(parent, name, ALLOC_PARA_FAIL);\n3006:\t\treturn de;\n3007:\t}\n3008:\tEXPORT_SYMBOL(d_alloc_trylock);\n3009:\t\n3010:\t/\n3011:\t * Move dentry from in-lookup state to busy-negative one.\n3012:\t \n3013:\t From now on d_in_lookup(dentry) will return false and dentry is gone from\n3014:\t * in-lookup hash.\n" }
71/3	2026/09/30 05:00	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 16263 output: 20 thoughts: 277 Thoughts: Analyzing Potential Race Conditions in NFS dentry Handling Okay, so I'm looking at this code and a couple of things are catching my attention. First, there's this comment in `d_alloc_trylock`: "The @name need not already have ->hash set." Right, that's interesting. I need to keep that in mind. Then, I'm reviewing the changes in `nfs_prime_dcache`. I see the `filename.hash` calculation is removed, and now `d_alloc_trylock` is called directly. It's used to replace `d_lookup` and `d_alloc_parallel`. Hold on... a lightbulb just went off! Does `d_alloc_trylock` handle the hash calculation internally if it's not pre-computed? It could potentially be doing it to handle cases where we are trying to find an existing dentry. If that's the case, and assuming that is happening in `try_lookup_noperm`, then it would handle the locking for that lookup. I need to verify that assumption. Time to dig into `try_lookup_noperm`.
72/3	2026/09/30 05:00	tool	grepper	0m Args: { "Expression": "try_lookup_noperm" } Results: { "Output": "Documentation/filesystems/porting.rst=1218=lookup_one_len_unlocked() and lookup_positive_unlocked() have been\nDocumentation/filesystems/porting.rst:1219:renamed to try_lookup_noperm(), lookup_noperm(),\nDocumentation/filesystems/porting.rst-1220-lookup_noperm_unlocked(), lookup_noperm_positive_unlocked(). They now\n--\nDocumentation/filesystems/porting.rst=1234=d_hash_and_lookup() is no longer exported or available outside the VFS.\nDocumentation/filesystems/porting.rst:1235:Use try_lookup_noperm() instead. This adds name validation and takes\nDocumentation/filesystems/porting.rst-1236-arguments in the opposite order but is otherwise identical.\nDocumentation/filesystems/porting.rst-1237-\nDocumentation/filesystems/porting.rst:1238:Using try_lookup_noperm() will require linux/namei.h to be included.\nDocumentation/filesystems/porting.rst-1239-\n--\nfs/autofs/dev-ioctl.c=411=static int autofs_dev_ioctl_timeout(struct file fp,\n--\nfs/autofs/dev-ioctl.c-434-\nfs/autofs/dev-ioctl.c:435:\t\tdentry = try_lookup_noperm(\u0026QSTR_LEN(param-\u003epath, path_len),\nfs/autofs/dev-ioctl.c-436-\t\t\t\t\t base);\n--\nfs/dcache.c=2831=struct dentry __d_alloc_parallel(struct dentry parent,\n--\nfs/dcache.c-2964- The @name must already have -\u003ehash set, as can be achieved\nfs/dcache.c:2965: * by e.g. try_lookup_noperm().\nfs/dcache.c-2966- \n--\nfs/dcache.c=2998=struct dentry d_alloc_trylock(struct dentry parent,\n--\nfs/dcache.c-3002-\nfs/dcache.c:3003:\tde = try_lookup_noperm(name, parent);\nfs/dcache.c-3004-\tif (!de)\n--\nfs/efivarfs/super.c=227=bool efivarfs_variable_is_present(efi_char16_t variable_name,\n--\nfs/efivarfs/super.c-244-\nfs/efivarfs/super.c:245:\tdentry = try_lookup_noperm(\u0026QSTR(name), sb-\u003es_root);\nfs/efivarfs/super.c-246-\tkfree(name);\n--\nfs/efivarfs/super.c=425=static int efivarfs_check_missing(efi_char16_t name16, efi_guid_t vendor,\n--\nfs/efivarfs/super.c-439-\nfs/efivarfs/super.c:440:\tdentry = try_lookup_noperm(\u0026QSTR(name), sb-\u003es_root);\nfs/efivarfs/super.c-441-\tif (IS_ERR(dentry)) {\n--\nfs/namei.c=3114=static int lookup_one_common(struct mnt_idmap idmap,\n--\nfs/namei.c-3124-/*\nfs/namei.c:3125: try_lookup_noperm - filesystem helper to lookup single pathname component\nfs/namei.c-3126- * @name:\tqstr storing pathname component to lookup\n--\nfs/namei.c-3144- /\nfs/namei.c:3145:struct dentry try_lookup_noperm(struct qstr name, struct dentry base)\nfs/namei.c-3146-{\n--\nfs/namei.c-3154-}\nfs/namei.c:3155:EXPORT_SYMBOL(try_lookup_noperm);\nfs/namei.c-3156-\n--\nfs/namei.c=3208=EXPORT_SYMBOL(lookup_one);\n--\nfs/namei.c-3221- * Returns: - A dentry, possibly negative, or\nfs/namei.c:3222: \t - same errors as try_lookup_noperm() or\nfs/namei.c-3223- \t - ERR_PTR(-ENOENT) if parent has been removed, or\n--\nfs/namei.c=3321=EXPORT_SYMBOL(lookup_one_positive_unlocked);\n--\nfs/namei.c-3333- \nfs/namei.c:3334: Unlike try_lookup_noperm() it does revalidate the dentry if it already\nfs/namei.c-3335- * existed.\n--\nfs/namei.c-3338- \t - ERR_PTR(-ENOENT) if parent has been removed, or\nfs/namei.c:3339: \t - same errors as try_lookup_noperm()\nfs/namei.c-3340- /\n--\nfs/namei.c=3355=EXPORT_SYMBOL(lookup_noperm_unlocked);\n--\nfs/namei.c-3366- \t - ERR_PTR(-ENOENT) if name cannot be found or parent has been removed, or\nfs/namei.c:3367: \t - same errors as try_lookup_noperm()\nfs/namei.c-3368- /\n--\nfs/proc/base.c=2099=bool proc_fill_cache(struct file file, struct dir_context ctx,\n--\nfs/proc/base.c-2108-\nfs/proc/base.c:2109:\tchild = try_lookup_noperm(\u0026qname, dir);\nfs/proc/base.c-2110-\tif (IS_ERR(child))\n--\nfs/smb/client/readdir.c=67=cifs_prime_dcache(struct dentry parent, struct qstr name,\n--\nfs/smb/client/readdir.c-79-\nfs/smb/client/readdir.c:80:\tdentry = try_lookup_noperm(name, parent);\nfs/smb/client/readdir.c-81-\tif (!dentry) {\n--\nfs/xfs/scrub/orphanage.c=431=xrep_adoption_check_dcache(\n--\nfs/xfs/scrub/orphanage.c-443-\nfs/xfs/scrub/orphanage.c:444:\td_child = try_lookup_noperm(\u0026qname, d_orphanage);\nfs/xfs/scrub/orphanage.c-445-\tif (IS_ERR(d_child)) {\n--\nfs/xfs/scrub/orphanage.c=473=xrep_adoption_zap_dcache(\n--\nfs/xfs/scrub/orphanage.c-485-\nfs/xfs/scrub/orphanage.c:486:\td_child = try_lookup_noperm(\u0026qname, d_orphanage);\nfs/xfs/scrub/orphanage.c-487-\twhile (!IS_ERR_OR_NULL(d_child)) {\n--\ninclude/linux/namei.h=67=int vfs_path_lookup(struct dentry , struct vfsmount , const char ,\n--\ninclude/linux/namei.h-69-\ninclude/linux/namei.h:70:extern struct dentry try_lookup_noperm(struct qstr , struct dentry );\ninclude/linux/namei.h-71-extern struct dentry lookup_noperm(struct qstr , struct dentry );\n--\nnet/sunrpc/rpc_pipe.c=1005=struct dentry rpc_d_lookup_sb(const struct super_block *sb,\n--\nnet/sunrpc/rpc_pipe.c-1007-{\nnet/sunrpc/rpc_pipe.c:1008:\treturn try_lookup_noperm(\u0026QSTR(dir_name), sb-\u003es_root);\nnet/sunrpc/rpc_pipe.c-1009-}\n--\nsecurity/selinux/selinuxfs.c=1974=int __init init_sel_fs(void)\n--\nsecurity/selinux/selinuxfs.c-1997-\nsecurity/selinux/selinuxfs.c:1998:\tselinux_null.dentry = try_lookup_noperm(\u0026null_name,\nsecurity/selinux/selinuxfs.c-1999-\t\t\t\t\t\t selinux_null.mnt-\u003emnt_root);\n" }
73/3	2026/09/30 05:00	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 19035 output: 35 thoughts: 12 Thoughts: Okay, here's my interpretation of "Let's check `try_lookup_noperm`" presented as a first-person expert thought process, aimed at an expert audience, and formatted as requested: Examining `try_lookup_noperm` Right, let's dive into this. "Let's check `try_lookup_noperm`." Okay, so the system, the context, whatever it is that I'm working with, requires a closer look at this particular function, `try_lookup_noperm`. Based on the name, my initial assumption is that this routine attempts a lookup, probably within some kind of security context or access control system, without the usual permission checks. I'm instantly thinking about the implications. What's it looking up? Why bypass permission checks? Is this for a performance optimization? A specific edge case? Perhaps it's an internal function used by a privileged process, or part of a bootstrapping sequence? The "no perm" part raises a red flag; this is usually a potential security vulnerability if not handled with absolute care. My expertise immediately brings to mind several questions: * What are the failure modes? Does it return a specific error code that tells me about the error? * How is `try_lookup_noperm` called? What's the call stack? Who's calling it? Is there input validation? Are there any preconditions that are assumed true by the calling function? * What is looked up? Is this something that should never be revealed? * What security boundary is this breaking? * Is it vulnerable to any race conditions, TOCTOU problems, or other concurrency issues? * What is its behaviour if the "no permission" condition fails, i.e. if it fails and permissions are not appropriate? * Is the caller aware of its actions? * Is the return value checked? Basically, I need to understand this function's purpose, its limitations, and, most critically, the why behind its existence. I need to understand this `try_lookup_noperm` function inside out. Time to start digging into the code and the surrounding context.
74/3	2026/09/30 05:00	tool	read-file	0m Args: { "File": "fs/namei.c", "FirstLine": 3140, "LineCount": 20 } Results: { "Contents": "3140:\t * - ref-counted dentry on success, or\n3141:\t * - %NULL if name could not be found, or\n3142:\t * - ERR_PTR(-EACCES) if name is dot or dotdot or contains a slash or nul, or\n3143:\t * - ERR_PTR() if fs provide -\u003ed_hash, and this returned an error.\n3144:\t /\n3145:\tstruct dentry try_lookup_noperm(struct qstr name, struct dentry base)\n3146:\t{\n3147:\t\tint err;\n3148:\t\n3149:\t\terr = lookup_noperm_common(name, base);\n3150:\t\tif (err)\n3151:\t\t\treturn ERR_PTR(err);\n3152:\t\n3153:\t\treturn d_lookup(base, name);\n3154:\t}\n3155:\tEXPORT_SYMBOL(try_lookup_noperm);\n3156:\t\n3157:\t/*\n3158:\t lookup_noperm - filesystem helper to lookup single pathname component\n3159:\t * @name:\tqstr storing pathname component to lookup\n" }
75/3	2026/09/30 05:00	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 19872 output: 35 thoughts: 14 Thoughts: Okay, here's my interpretation of that thought process, tailored for an expert audience, and presented as if it were my own internal monologue: Checking `lookup_noperm_common` Alright, let's dive into this `lookup_noperm_common` situation. My gut tells me there's something to investigate here. It's a key function in [insert specific relevant area of the expert's field, e.g., permission handling, access control, security checks, etc.]. The naming convention itself is suggestive. The "noperm" part, of course, is what I'm interested in - it's a critical piece of any solid implementation. I need to take a closer look at what this function actually does. Is it as expected, or is it a shortcut that could be exploited? I need to know how it interacts with other system components, the data it processes, and the potential impact of any weaknesses. Let's see... I'm thinking I'll start with [specify a starting point relevant to the expert's field of knowledge]. My immediate goal is to understand precisely what makes this function common - and how it is connected to a "noperm" context.
76/3	2026/09/30 05:00	tool	read-file	0m Args: { "File": "fs/namei.c", "FirstLine": 3114, "LineCount": 30 } Results: { "Contents": "3114:\tstatic int lookup_one_common(struct mnt_idmap idmap,\n3115:\t\t\t\t struct qstr qname, struct dentry base)\n3116:\t{\n3117:\t\tint err;\n3118:\t\terr = lookup_noperm_common(qname, base);\n3119:\t\tif (err \u003c 0)\n3120:\t\t\treturn err;\n3121:\t\treturn inode_permission(idmap, base-\u003ed_inode, MAY_EXEC);\n3122:\t}\n3123:\t\n3124:\t/\n3125:\t try_lookup_noperm - filesystem helper to lookup single pathname component\n3126:\t * @name:\tqstr storing pathname component to lookup\n3127:\t * @base:\tbase directory to lookup from\n3128:\t \n3129:\t Look up a dentry by name in the dcache, returning NULL if it does not\n3130:\t * currently exist or an error if there is a problem with the name.\n3131:\t * The function does not try to create a dentry and if one\n3132:\t * is found it doesn't try to revalidate it.\n3133:\t \n3134:\t Note that this routine is purely a helper for filesystem usage and should\n3135:\t * not be called by generic code. It does no permission checking.\n3136:\t \n3137:\t No locks need be held - only a counted reference to @base is needed.\n3138:\t \n3139:\t Returns:\n3140:\t * - ref-counted dentry on success, or\n3141:\t * - %NULL if name could not be found, or\n3142:\t * - ERR_PTR(-EACCES) if name is dot or dotdot or contains a slash or nul, or\n3143:\t * - ERR_PTR() if fs provide -\u003ed_hash, and this returned an error.\n" }
77/3	2026/09/30 05:00	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 20701 output: 37 thoughts: 1283 Thoughts: Analysis of NFS Patch for Potential Uninitialized Variable Issues Alright, let's break down this NFS patch and see if it introduces any nasties related to uninitialized variables. My concern is always about potential security vulnerabilities due to reading uninitialized memory. I'm seeing changes across a few files, so I need to go through each one carefully. Firstly, the most significant change I noticed is in `nfs_call_unlink` where they're explicitly setting `data->args.name.hash` using `full_name_hash`. This is good; it's fixing a potential problem by ensuring the hash is properly initialized before `d_alloc_parallel` is called. It looks like the hash was missing before, and this fixes that. Now, let's step through the other changes file by file. 1. `fs/nfs/dir.c`: I'm seeing a pattern of replacing `d_lookup` + `d_alloc_parallel` with `d_alloc_trylock`, and using `d_splice_alias` instead of `d_add` in a few places. Also I am happy to see that `d_drop(dentry)` is consistently moved to the error path in `nfs_add_or_obtain` and other places. I also see they're doing a simplification of dentry lookup and drop handling in `nfs_atomic_open`. The `block_revalidate` change with `write_seqcount_invalidate` looks safe. Now, about those variables... * In `nfs_sillyrename`, I see `old` and `sdentry` being used: `old = nfs_lookup(dir, sdentry, 0);`. `old` is assigned the return of `nfs_lookup` and `sdentry` initialized using `d_alloc_trylock`. Good, no uninitialized reads here. * In `nfs_atomic_open`, the `dir_verifier` variable is always assigned a value, so no issue there. * In `nfs_rename`, `dentry = d_duplicate(new_dentry);` is checked and initialized, then freed at the end. Looks good. 2. `fs/nfs/nfs4proc.c`: Just a removal of `d_drop(dentry)` before `d_splice_alias`. This is just a cleanup and no new variables or dangerous operations. 3. `fs/nfs/unlink.c`: Again, we already covered the initialization of `data->args.name.hash` in `nfs_call_unlink`. Overall, my assessment is that this patch doesn't introduce any new instances of reading potentially uninitialized variables. The key change in `nfs_call_unlink` is, in fact, a fix for a potential uninitialized state. All the new variables seem to be properly initialized before use. No kernel structures are sent to user space where uninitialized fields could be a problem. So, I am reasonably confident that this patch is safe from this specific type of vulnerability.
78/3	2026/09/30 05:00	tool	read-file	0m Args: { "File": "fs/nfs/dir.c", "FirstLine": 2760, "LineCount": 40 } Results: { "Contents": "2760:\tint nfs_rename(struct mnt_idmap idmap, struct inode old_dir,\n2761:\t\t struct dentry old_dentry, struct inode new_dir,\n2762:\t\t struct dentry new_dentry, unsigned int flags)\n2763:\t{\n2764:\t\tstruct inode old_inode = d_inode(old_dentry);\n2765:\t\tstruct inode new_inode = d_inode(new_dentry);\n2766:\t\tunsigned long new_gencount = 0;\n2767:\t\tstruct dentry dentry = NULL;\n2768:\t\tstruct rpc_task task;\n2769:\t\tbool must_unblock = false;\n2770:\t\tint error = -EBUSY;\n2771:\t\n2772:\t\tif (flags)\n2773:\t\t\treturn -EINVAL;\n2774:\t\n2775:\t\tdfprintk(VFS, \"NFS: rename(%pd2 -\u003e %pd2, ct=%d)\\n\",\n2776:\t\t\t old_dentry, new_dentry,\n2777:\t\t\t d_count(new_dentry));\n2778:\t\n2779:\t\ttrace_nfs_rename_enter(old_dir, old_dentry, new_dir, new_dentry);\n2780:\t\t/\n2781:\t\t * For non-directories, check whether the target is busy and if so,\n2782:\t\t * make a copy of the dentry and then do a silly-rename. If the\n2783:\t\t * silly-rename succeeds, the copied dentry is hashed and becomes\n2784:\t\t * the new target.\n2785:\t\t /\n2786:\t\tif (new_inode \u0026\u0026 !S_ISDIR(new_inode-\u003ei_mode)) {\n2787:\t\t\t/ We must prevent any concurrent open until the unlink\n2788:\t\t\t * completes. -\u003ed_revalidate will wait for -\u003ed_fsdata\n2789:\t\t\t * to clear. We set it here to ensure no lookup succeeds until\n2790:\t\t\t * the unlink is complete on the server.\n2791:\t\t\t */\n2792:\t\t\terror = -ETXTBSY;\n2793:\t\t\tif (WARN_ON(new_dentry-\u003ed_flags \u0026 DCACHE_NFSFS_RENAMED) \|\|\n2794:\t\t\t WARN_ON(new_dentry-\u003ed_fsdata == NFS_FSDATA_BLOCKED))\n2795:\t\t\t\tgoto out;\n2796:\t\n2797:\t\t\tspin_lock(\u0026new_dentry-\u003ed_lock);\n2798:\t\t\tif (d_count(new_dentry) \u003e 2) {\n2799:\t\t\t\tint err;\n" }
79/3	2026/09/30 05:00	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 23410 output: 274 thoughts: 674 Thoughts: KMSAN Assessment: No Need for Dedicated Fuzzing Okay, so I've just reviewed this patch. Line 2767 confirms `struct dentry dentry = NULL;`, which I understand sets the stage. But I need to dive deeper than that. My analysis focuses on potential memory safety issues, and specifically whether KMSAN (Kernel Memory Sanitizer) is needed* here. My initial concern is always around uninitialized memory: are we allocating or initializing complex data structures where uninitialized fields could be read later in reachable code? In this case, I see that `d_duplicate()` calls VFS helper which allocates, but there's no indication of such a problem. I also need to check for potential bounds check issues or ways to expose uninitialized bytes from existing buffers. Nothing jumps out as problematic here. So, what is this patch actually doing? It's a VFS/NFS patch, primarily focused on improving dentry lookup synchronization. We're talking about changes related to sillyrename, negative dentry revalidation, and locking/concurrency during open/rename/unlink/link operations. Specifically, this patch introduces and uses `d_alloc_trylock()` and `d_duplicate()` as dcache primitives, for parallel lookup and atomic dentry management. It's also fixing and adjusting concurrency handling in NFS: like revalidating negative dentries, invalidating `d_seq`, using `d_splice_alias` appropriately. It also ensures that in `nfs_call_unlink` the hash is explicitly calculated. The core of these changes are all related to concurrency, locking, the lifetime of dentries/inodes, dcache state invariants, and reference counting issues. If there are bugs, they're likely to manifest as: * Deadlocks or locking order problems (LOCKDEP would catch those). * Use-after-free errors or refcounting errors on dentries/inodes (KASAN, refcount checks, and VFS checks will detect these). * Inode or dentry alias or unhashed state corruption (VFS WARN\_ON or KASAN would report). * Race conditions or bugs in the negative dentry revalidation logic. Crucially, though, none of these changes create a risk of reading uninitialized stack or heap memory or leaking uninitialized memory to userspace. All variables are properly initialized. Therefore, I'm confident that standard KASAN and LOCKDEP are fully appropriate for finding potential regressions. A dedicated KMSAN fuzzing session is not warranted here. Hence, `NeedsKMSAN = false`. I've carefully checked all the points, and I'm ready to set the results.
80/3	2026/09/30 05:00	tool	set-results	0m Args: { "KMSANReasoning": "The patch refactors NFS dentry handling and concurrency control across lookup, atomic_open, link, sillyrename, and unlink operations. Specifically, it adopts dcache helpers such as d_alloc_trylock(), d_duplicate(), and d_splice_alias(), refines dentry invalidation (including sequence count invalidation in block_revalidate()), and ensures proper hashing in nfs_call_unlink().\n\nNo uninitialized memory hazards are introduced or exposed:\n1. No kernel structures or data buffers are copied to user space (no copy_to_user, put_user, netlink messages, ioctls, or socket options).\n2. All local variables touched or introduced (such as 'sdentry', 'old', 'silly') are fully initialized before use.\n3. The changes operate entirely on dentry reference counting, lookup states, and VFS synchronization.\n\nAny bugs that might arise from these modifications would involve locking deadlocks, sequence count inconsistencies, use-after-free, or refcount imbalances on dentries and inodes—all of which are caught by standard KASAN, LOCKDEP, and kernel debug assertions. Thus, dedicated KMSAN fuzzing is not justified.", "NeedsKMSAN": false } Results: { "KMSANReasoning": "The patch refactors NFS dentry handling and concurrency control across lookup, atomic_open, link, sillyrename, and unlink operations. Specifically, it adopts dcache helpers such as d_alloc_trylock(), d_duplicate(), and d_splice_alias(), refines dentry invalidation (including sequence count invalidation in block_revalidate()), and ensures proper hashing in nfs_call_unlink().\n\nNo uninitialized memory hazards are introduced or exposed:\n1. No kernel structures or data buffers are copied to user space (no copy_to_user, put_user, netlink messages, ioctls, or socket options).\n2. All local variables touched or introduced (such as 'sdentry', 'old', 'silly') are fully initialized before use.\n3. The changes operate entirely on dentry reference counting, lookup states, and VFS synchronization.\n\nAny bugs that might arise from these modifications would involve locking deadlocks, sequence count inconsistencies, use-after-free, or refcount imbalances on dentries and inodes—all of which are caught by standard KASAN, LOCKDEP, and kernel debug assertions. Thus, dedicated KMSAN fuzzing is not justified.", "NeedsKMSAN": false }

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