| Seq | Timestamp | Type | Name | Duration |
|---|---|---|---|---|
| 0/0 | 2026/06/30 14:28 | flow | patch-triage |
0mArgs:null Results: {
"EnableConfigs": [
"EXT4_FS"
],
"FocusSymbols": [
"ext4_put_ea_inode",
"ext4_ea_inode_work",
"ext4_xattr_delete_inode",
"ext4_xattr_block_set",
"ext4_xattr_inode_dec_ref_all"
],
"Reasoning": "The patch introduces a new asynchronous mechanism for releasing ext4 Extended Attribute (EA) inodes to avoid lock ordering issues. It replaces the `ext4_xattr_inode_array` with a lockless list and a delayed workqueue (`ext4_ea_inode_work`). This is a functional change in core ext4 xattr handling and should be fuzzed to ensure there are no use-after-free, memory leaks, or race conditions in the new deferred iput logic.",
"WorthFuzzing": true
} |
| 1/1 | 2026/06/30 14:28 | action | read-patch-diff |
0mArgs:null Results: {
"PatchDiff": "commit fa619f539b2da48aff58bfdf2032857281dab4cc\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Tue Jun 30 14:28:17 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h\nindex b37c136ea3ab33..b9b0ada7774bb4 100644\n--- a/fs/ext4/ext4.h\n+++ b/fs/ext4/ext4.h\n@@ -1070,8 +1070,14 @@ struct ext4_inode_info {\n \t * between readers of EAs and writers of regular file data, so\n \t * instead we synchronize on xattr_sem when reading or changing\n \t * EAs.\n+\t *\n+\t * EA inodes (EXT4_EA_INODE_FL) do not use xattr_sem; they reuse\n+\t * the space for deferred iput linkage.\n \t */\n-\tstruct rw_semaphore xattr_sem;\n+\tunion {\n+\t\tstruct rw_semaphore xattr_sem;\n+\t\tstruct llist_node i_ea_iput_node;\n+\t};\n \n \t/*\n \t * Inodes with EXT4_STATE_ORPHAN_FILE use i_orphan_idx. Otherwise\n@@ -1770,6 +1776,11 @@ struct ext4_sb_info {\n \tstruct ext4_es_stats s_es_stats;\n \tstruct mb_cache *s_ea_block_cache;\n \tstruct mb_cache *s_ea_inode_cache;\n+\n+\t/* Deferred iput for EA inodes to avoid lock ordering issues */\n+\tstruct llist_head s_ea_inode_to_free;\n+\tstruct delayed_work s_ea_inode_work;\n+\n \tspinlock_t s_es_lock ____cacheline_aligned_in_smp;\n \n \t/* Journal triggers for checksum computation */\ndiff --git a/fs/ext4/inode.c b/fs/ext4/inode.c\nindex ce99807c5f5b2c..747c52c232cc03 100644\n--- a/fs/ext4/inode.c\n+++ b/fs/ext4/inode.c\n@@ -176,7 +176,6 @@ void ext4_evict_inode(struct inode *inode)\n \t * (xattr block freeing), bitmap, group descriptor (inode freeing)\n \t */\n \tint extra_credits = 6;\n-\tstruct ext4_xattr_inode_array *ea_inode_array = NULL;\n \tbool freeze_protected = false;\n \n \ttrace_ext4_evict_inode(inode);\n@@ -281,8 +280,7 @@ void ext4_evict_inode(struct inode *inode)\n \t}\n \n \t/* Remove xattr references. */\n-\terr = ext4_xattr_delete_inode(handle, inode, \u0026ea_inode_array,\n-\t\t\t\t extra_credits);\n+\terr = ext4_xattr_delete_inode(handle, inode, extra_credits);\n \tif (err) {\n \t\text4_warning(inode-\u003ei_sb, \"xattr delete (err %d)\", err);\n stop_handle:\n@@ -290,7 +288,6 @@ void ext4_evict_inode(struct inode *inode)\n \t\text4_orphan_del(NULL, inode);\n \t\tif (freeze_protected)\n \t\t\tsb_end_intwrite(inode-\u003ei_sb);\n-\t\text4_xattr_inode_array_free(ea_inode_array);\n \t\tgoto no_delete;\n \t}\n \n@@ -320,7 +317,6 @@ void ext4_evict_inode(struct inode *inode)\n \text4_journal_stop(handle);\n \tif (freeze_protected)\n \t\tsb_end_intwrite(inode-\u003ei_sb);\n-\text4_xattr_inode_array_free(ea_inode_array);\n \treturn;\n no_delete:\n \t/*\ndiff --git a/fs/ext4/super.c b/fs/ext4/super.c\nindex 245f67d10ded34..3efa5a817bef4f 100644\n--- a/fs/ext4/super.c\n+++ b/fs/ext4/super.c\n@@ -1303,6 +1303,8 @@ static void ext4_put_super(struct super_block *sb)\n \t\t\t \u0026sb-\u003es_uuid);\n \n \text4_unregister_li_request(sb);\n+\t/* Drain deferred EA inode iputs while quota is still active. */\n+\tflush_delayed_work(\u0026sbi-\u003es_ea_inode_work);\n \text4_quotas_off(sb, EXT4_MAXQUOTAS);\n \n \tdestroy_workqueue(sbi-\u003ersv_conversion_wq);\n@@ -1423,6 +1425,13 @@ static struct inode *ext4_alloc_inode(struct super_block *sb)\n \tmemset(\u0026ei-\u003ei_dquot, 0, sizeof(ei-\u003ei_dquot));\n #endif\n \tei-\u003ejinode = NULL;\n+\t/*\n+\t * Reinitialize xattr_sem every allocation because EA inodes\n+\t * share this space with i_ea_iput_node (via union) which may\n+\t * have overwritten the semaphore when the slab object was\n+\t * previously used as an EA inode.\n+\t */\n+\tinit_rwsem(\u0026ei-\u003exattr_sem);\n \tINIT_LIST_HEAD(\u0026ei-\u003ei_rsv_conversion_list);\n \tspin_lock_init(\u0026ei-\u003ei_completed_io_lock);\n \tei-\u003ei_sync_tid = 0;\n@@ -1488,7 +1497,6 @@ static void init_once(void *foo)\n \tstruct ext4_inode_info *ei = foo;\n \n \tINIT_LIST_HEAD(\u0026ei-\u003ei_orphan);\n-\tinit_rwsem(\u0026ei-\u003exattr_sem);\n \tinit_rwsem(\u0026ei-\u003ei_data_sem);\n \tinode_init_once(\u0026ei-\u003evfs_inode);\n \text4_fc_init_inode(\u0026ei-\u003evfs_inode);\n@@ -5497,6 +5505,8 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)\n \t\t\t ext4_has_feature_orphan_present(sb) ||\n \t\t\t ext4_has_feature_journal_needs_recovery(sb));\n \n+\text4_init_ea_inode_work(sbi);\n+\n \tif (ext4_has_feature_mmp(sb) \u0026\u0026 !sb_rdonly(sb)) {\n \t\terr = ext4_multi_mount_protect(sb, le64_to_cpu(es-\u003es_mmp_block));\n \t\tif (err)\n@@ -5747,6 +5757,8 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)\n \treturn 0;\n \n failed_mount9:\n+\t/* Drain deferred EA inode iputs before quota shutdown */\n+\tflush_delayed_work(\u0026sbi-\u003es_ea_inode_work);\n \text4_quotas_off(sb, EXT4_MAXQUOTAS);\n failed_mount8: __maybe_unused\n \text4_release_orphan_info(sb);\n@@ -5767,6 +5779,8 @@ failed_mount8: __maybe_unused\n \tif (EXT4_SB(sb)-\u003ersv_conversion_wq)\n \t\tdestroy_workqueue(EXT4_SB(sb)-\u003ersv_conversion_wq);\n failed_mount_wq:\n+\t/* Drain deferred EA inode iputs before freeing structures */\n+\tflush_delayed_work(\u0026sbi-\u003es_ea_inode_work);\n \text4_xattr_destroy_cache(sbi-\u003es_ea_inode_cache);\n \tsbi-\u003es_ea_inode_cache = NULL;\n \n@@ -5777,6 +5791,8 @@ failed_mount8: __maybe_unused\n \t\text4_journal_destroy(sbi, sbi-\u003es_journal);\n \t}\n failed_mount3a:\n+\t/* Drain deferred EA inode iputs from journal replay */\n+\tflush_delayed_work(\u0026sbi-\u003es_ea_inode_work);\n \text4_es_unregister_shrinker(sbi);\n failed_mount3:\n \t/* flush s_sb_upd_work before sbi destroy */\ndiff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c\nindex 982a1f831e2282..4ae6ce1115660e 100644\n--- a/fs/ext4/xattr.c\n+++ b/fs/ext4/xattr.c\n@@ -114,10 +114,6 @@ const struct xattr_handler * const ext4_xattr_handlers[] = {\n #define EA_INODE_CACHE(inode)\t(((struct ext4_sb_info *) \\\n \t\t\t\tinode-\u003ei_sb-\u003es_fs_info)-\u003es_ea_inode_cache)\n \n-static int\n-ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,\n-\t\t\tstruct inode *inode);\n-\n #ifdef CONFIG_LOCKDEP\n void ext4_xattr_inode_set_class(struct inode *ea_inode)\n {\n@@ -567,7 +563,7 @@ ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry,\n \t\t\t\t\tea_inode-\u003ei_ino, true /* reusable */);\n \t}\n out:\n-\tiput(ea_inode);\n+\text4_put_ea_inode(ea_inode);\n \treturn err;\n }\n \n@@ -1104,10 +1100,10 @@ static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,\n \t\terr = ext4_xattr_inode_inc_ref(handle, ea_inode);\n \t\tif (err) {\n \t\t\text4_warning_inode(ea_inode, \"inc ref error %d\", err);\n-\t\t\tiput(ea_inode);\n+\t\t\text4_put_ea_inode(ea_inode);\n \t\t\tgoto cleanup;\n \t\t}\n-\t\tiput(ea_inode);\n+\t\text4_put_ea_inode(ea_inode);\n \t}\n \treturn 0;\n \n@@ -1133,7 +1129,7 @@ static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,\n \t\tif (err)\n \t\t\text4_warning_inode(ea_inode, \"cleanup dec ref error %d\",\n \t\t\t\t\t err);\n-\t\tiput(ea_inode);\n+\t\text4_put_ea_inode(ea_inode);\n \t}\n \treturn saved_err;\n }\n@@ -1160,7 +1156,6 @@ static void\n ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,\n \t\t\t struct buffer_head *bh,\n \t\t\t struct ext4_xattr_entry *first, bool block_csum,\n-\t\t\t struct ext4_xattr_inode_array **ea_inode_array,\n \t\t\t int extra_credits, bool skip_quota)\n {\n \tstruct inode *ea_inode;\n@@ -1197,14 +1192,6 @@ ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,\n \t\tif (err)\n \t\t\tcontinue;\n \n-\t\terr = ext4_expand_inode_array(ea_inode_array, ea_inode);\n-\t\tif (err) {\n-\t\t\text4_warning_inode(ea_inode,\n-\t\t\t\t\t \"Expand inode array err=%d\", err);\n-\t\t\tiput(ea_inode);\n-\t\t\tcontinue;\n-\t\t}\n-\n \t\terr = ext4_journal_ensure_credits_fn(handle, credits, credits,\n \t\t\text4_free_metadata_revoke_credits(parent-\u003ei_sb, 1),\n \t\t\text4_xattr_restart_fn(handle, parent, bh, block_csum,\n@@ -1212,6 +1199,7 @@ ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,\n \t\tif (err \u003c 0) {\n \t\t\text4_warning_inode(ea_inode, \"Ensure credits err=%d\",\n \t\t\t\t\t err);\n+\t\t\text4_put_ea_inode(ea_inode);\n \t\t\tcontinue;\n \t\t}\n \t\tif (err \u003e 0) {\n@@ -1221,6 +1209,7 @@ ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,\n \t\t\t\text4_warning_inode(ea_inode,\n \t\t\t\t\t\t\"Re-get write access err=%d\",\n \t\t\t\t\t\terr);\n+\t\t\t\text4_put_ea_inode(ea_inode);\n \t\t\t\tcontinue;\n \t\t\t}\n \t\t}\n@@ -1229,6 +1218,7 @@ ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,\n \t\tif (err) {\n \t\t\text4_warning_inode(ea_inode, \"ea_inode dec ref err=%d\",\n \t\t\t\t\t err);\n+\t\t\text4_put_ea_inode(ea_inode);\n \t\t\tcontinue;\n \t\t}\n \n@@ -1245,6 +1235,7 @@ ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,\n \t\tentry-\u003ee_value_inum = 0;\n \t\tentry-\u003ee_value_size = 0;\n \n+\t\text4_put_ea_inode(ea_inode);\n \t\tdirty = true;\n \t}\n \n@@ -1271,7 +1262,6 @@ ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,\n static void\n ext4_xattr_release_block(handle_t *handle, struct inode *inode,\n \t\t\t struct buffer_head *bh,\n-\t\t\t struct ext4_xattr_inode_array **ea_inode_array,\n \t\t\t int extra_credits)\n {\n \tstruct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);\n@@ -1313,7 +1303,6 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,\n \t\t\text4_xattr_inode_dec_ref_all(handle, inode, bh,\n \t\t\t\t\t\t BFIRST(bh),\n \t\t\t\t\t\t true /* block_csum */,\n-\t\t\t\t\t\t ea_inode_array,\n \t\t\t\t\t\t extra_credits,\n \t\t\t\t\t\t true /* skip_quota */);\n \t\text4_free_blocks(handle, inode, bh, 0, 1,\n@@ -1505,7 +1494,7 @@ static struct inode *ext4_xattr_inode_create(handle_t *handle,\n \t\t\tif (ext4_xattr_inode_dec_ref(handle, ea_inode))\n \t\t\t\text4_warning_inode(ea_inode,\n \t\t\t\t\t\"cleanup dec ref error %d\", err);\n-\t\t\tiput(ea_inode);\n+\t\t\text4_put_ea_inode(ea_inode);\n \t\t\treturn ERR_PTR(err);\n \t\t}\n \n@@ -1564,7 +1553,7 @@ ext4_xattr_inode_cache_find(struct inode *inode, const void *value,\n \t\t\tkvfree(ea_data);\n \t\t\treturn ea_inode;\n \t\t}\n-\t\tiput(ea_inode);\n+\t\text4_put_ea_inode(ea_inode);\n \tnext_entry:\n \t\tce = mb_cache_entry_find_next(ea_inode_cache, ce);\n \t}\n@@ -1615,7 +1604,7 @@ static struct inode *ext4_xattr_inode_lookup_create(handle_t *handle,\n \t\t\t\t ea_inode-\u003ei_ino, true /* reusable */);\n \treturn ea_inode;\n out_err:\n-\tiput(ea_inode);\n+\text4_put_ea_inode(ea_inode);\n \text4_xattr_inode_free_quota(inode, NULL, value_len);\n \treturn ERR_PTR(err);\n }\n@@ -1848,7 +1837,7 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,\n \n \tret = 0;\n out:\n-\tiput(old_ea_inode);\n+\text4_put_ea_inode(old_ea_inode);\n \treturn ret;\n }\n \n@@ -2010,7 +1999,7 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,\n \t\t\t\told_ea_inode_quota = le32_to_cpu(\n \t\t\t\t\t\ts-\u003ehere-\u003ee_value_size);\n \t\t\t}\n-\t\t\tiput(tmp_inode);\n+\t\t\text4_put_ea_inode(tmp_inode);\n \n \t\t\ts-\u003ehere-\u003ee_value_inum = 0;\n \t\t\ts-\u003ehere-\u003ee_value_size = 0;\n@@ -2150,7 +2139,7 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,\n \t\t\t\t\text4_warning_inode(ea_inode,\n \t\t\t\t\t\t\t \"dec ref error=%d\",\n \t\t\t\t\t\t\t error);\n-\t\t\t\tiput(ea_inode);\n+\t\t\t\text4_put_ea_inode(ea_inode);\n \t\t\t\tea_inode = NULL;\n \t\t\t}\n \n@@ -2182,12 +2171,8 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,\n \n \t/* Drop the previous xattr block. */\n \tif (bs-\u003ebh \u0026\u0026 bs-\u003ebh != new_bh) {\n-\t\tstruct ext4_xattr_inode_array *ea_inode_array = NULL;\n-\n \t\text4_xattr_release_block(handle, inode, bs-\u003ebh,\n-\t\t\t\t\t \u0026ea_inode_array,\n \t\t\t\t\t 0 /* extra_credits */);\n-\t\text4_xattr_inode_array_free(ea_inode_array);\n \t}\n \terror = 0;\n \n@@ -2203,7 +2188,7 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,\n \t\t\text4_xattr_inode_free_quota(inode, ea_inode,\n \t\t\t\t\t\t i_size_read(ea_inode));\n \t\t}\n-\t\tiput(ea_inode);\n+\t\text4_put_ea_inode(ea_inode);\n \t}\n \tif (ce)\n \t\tmb_cache_entry_put(ea_block_cache, ce);\n@@ -2285,7 +2270,7 @@ int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,\n \n \t\t\text4_xattr_inode_free_quota(inode, ea_inode,\n \t\t\t\t\t\t i_size_read(ea_inode));\n-\t\t\tiput(ea_inode);\n+\t\t\text4_put_ea_inode(ea_inode);\n \t\t}\n \t\treturn error;\n \t}\n@@ -2297,7 +2282,7 @@ int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,\n \t\theader-\u003eh_magic = cpu_to_le32(0);\n \t\text4_clear_inode_state(inode, EXT4_STATE_XATTR);\n \t}\n-\tiput(ea_inode);\n+\text4_put_ea_inode(ea_inode);\n \treturn 0;\n }\n \n@@ -2863,46 +2848,6 @@ int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,\n \treturn error;\n }\n \n-#define EIA_INCR 16 /* must be 2^n */\n-#define EIA_MASK (EIA_INCR - 1)\n-\n-/* Add the large xattr @inode into @ea_inode_array for deferred iput().\n- * If @ea_inode_array is new or full it will be grown and the old\n- * contents copied over.\n- */\n-static int\n-ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,\n-\t\t\tstruct inode *inode)\n-{\n-\tif (*ea_inode_array == NULL) {\n-\t\t/*\n-\t\t * Start with 15 inodes, so it fits into a power-of-two size.\n-\t\t */\n-\t\t(*ea_inode_array) = kmalloc_flex(**ea_inode_array, inodes,\n-\t\t\t\t\t\t EIA_MASK, GFP_NOFS);\n-\t\tif (*ea_inode_array == NULL)\n-\t\t\treturn -ENOMEM;\n-\t\t(*ea_inode_array)-\u003ecount = 0;\n-\t} else if (((*ea_inode_array)-\u003ecount \u0026 EIA_MASK) == EIA_MASK) {\n-\t\t/* expand the array once all 15 + n * 16 slots are full */\n-\t\tstruct ext4_xattr_inode_array *new_array = NULL;\n-\n-\t\tnew_array = kmalloc_flex(**ea_inode_array, inodes,\n-\t\t\t\t\t (*ea_inode_array)-\u003ecount + EIA_INCR,\n-\t\t\t\t\t GFP_NOFS);\n-\t\tif (new_array == NULL)\n-\t\t\treturn -ENOMEM;\n-\t\tmemcpy(new_array, *ea_inode_array,\n-\t\t struct_size(*ea_inode_array, inodes,\n-\t\t\t\t (*ea_inode_array)-\u003ecount));\n-\t\tkfree(*ea_inode_array);\n-\t\t*ea_inode_array = new_array;\n-\t}\n-\t(*ea_inode_array)-\u003ecount++;\n-\t(*ea_inode_array)-\u003einodes[(*ea_inode_array)-\u003ecount - 1] = inode;\n-\treturn 0;\n-}\n-\n /*\n * ext4_xattr_delete_inode()\n *\n@@ -2913,7 +2858,6 @@ ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,\n * references on xattr block and xattr inodes.\n */\n int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,\n-\t\t\t struct ext4_xattr_inode_array **ea_inode_array,\n \t\t\t int extra_credits)\n {\n \tstruct buffer_head *bh = NULL;\n@@ -2952,7 +2896,6 @@ int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,\n \t\t\text4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,\n \t\t\t\t\t\t IFIRST(header),\n \t\t\t\t\t\t false /* block_csum */,\n-\t\t\t\t\t\t ea_inode_array,\n \t\t\t\t\t\t extra_credits,\n \t\t\t\t\t\t false /* skip_quota */);\n \t}\n@@ -2986,12 +2929,12 @@ int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,\n \t\t\t\t\tcontinue;\n \t\t\t\text4_xattr_inode_free_quota(inode, ea_inode,\n \t\t\t\t\t le32_to_cpu(entry-\u003ee_value_size));\n-\t\t\t\tiput(ea_inode);\n+\t\t\t\text4_put_ea_inode(ea_inode);\n \t\t\t}\n \n \t\t}\n \n-\t\text4_xattr_release_block(handle, inode, bh, ea_inode_array,\n+\t\text4_xattr_release_block(handle, inode, bh,\n \t\t\t\t\t extra_credits);\n \t\t/*\n \t\t * Update i_file_acl value in the same transaction that releases\n@@ -3013,16 +2956,63 @@ int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,\n \treturn error;\n }\n \n-void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)\n+/*\n+ * Worker function for deferred EA inode iput. Processes all inodes queued\n+ * on s_ea_inode_to_free in a context free of xattr_sem/jbd2 handle locks.\n+ */\n+static void ext4_ea_inode_work(struct work_struct *work)\n {\n-\tint idx;\n+\tstruct ext4_sb_info *sbi = container_of(to_delayed_work(work),\n+\t\t\t\t\t\tstruct ext4_sb_info,\n+\t\t\t\t\t\ts_ea_inode_work);\n+\tstruct llist_node *node = llist_del_all(\u0026sbi-\u003es_ea_inode_to_free);\n \n-\tif (ea_inode_array == NULL)\n+\twhile (node) {\n+\t\tstruct ext4_inode_info *ei = container_of(node,\n+\t\t\t\t\tstruct ext4_inode_info, i_ea_iput_node);\n+\t\tnode = node-\u003enext;\n+\t\tiput(\u0026ei-\u003evfs_inode);\n+\t}\n+}\n+\n+/*\n+ * Release a VFS reference on an EA inode. Must be used instead of iput()\n+ * in any context where xattr_sem or a jbd2 handle is held.\n+ *\n+ * If this is not the last reference, drops it immediately via\n+ * iput_if_not_last() with no further action needed.\n+ *\n+ * If this is the last reference, the inode is linked onto a per-sb\n+ * llist via i_ea_iput_node (embedded in ext4_inode_info, sharing space\n+ * with the unused xattr_sem) and a delayed worker performs the final\n+ * iput() in a clean context.\n+ *\n+ * Note: while an inode is on s_ea_inode_to_free, the unconsumed i_count\n+ * reference (still 1) keeps it in the inode cache, so any concurrent\n+ * iget() bumps i_count to \u003e= 2 and iput_if_not_last() will succeed.\n+ * Nobody will add the inode a second time until ext4_ea_inode_work()\n+ * drops that reference via iput().\n+ */\n+void ext4_put_ea_inode(struct inode *inode)\n+{\n+\tif (!inode)\n+\t\treturn;\n+\tWARN_ON_ONCE(!(EXT4_I(inode)-\u003ei_flags \u0026 EXT4_EA_INODE_FL));\n+\tif (iput_if_not_last(inode))\n \t\treturn;\n+\tllist_add(\u0026EXT4_I(inode)-\u003ei_ea_iput_node,\n+\t\t \u0026EXT4_SB(inode-\u003ei_sb)-\u003es_ea_inode_to_free);\n+\t/*\n+\t * Use a short delay to allow multiple EA inodes to accumulate,\n+\t * reducing workqueue wakeups when several are released together.\n+\t */\n+\tschedule_delayed_work(\u0026EXT4_SB(inode-\u003ei_sb)-\u003es_ea_inode_work, 1);\n+}\n \n-\tfor (idx = 0; idx \u003c ea_inode_array-\u003ecount; ++idx)\n-\t\tiput(ea_inode_array-\u003einodes[idx]);\n-\tkfree(ea_inode_array);\n+void ext4_init_ea_inode_work(struct ext4_sb_info *sbi)\n+{\n+\tinit_llist_head(\u0026sbi-\u003es_ea_inode_to_free);\n+\tINIT_DELAYED_WORK(\u0026sbi-\u003es_ea_inode_work, ext4_ea_inode_work);\n }\n \n /*\ndiff --git a/fs/ext4/xattr.h b/fs/ext4/xattr.h\nindex 1fedf44d4fb65e..821dc6a50e51e7 100644\n--- a/fs/ext4/xattr.h\n+++ b/fs/ext4/xattr.h\n@@ -131,11 +131,6 @@ struct ext4_xattr_ibody_find {\n \tstruct ext4_iloc iloc;\n };\n \n-struct ext4_xattr_inode_array {\n-\tunsigned int count;\n-\tstruct inode *inodes[] __counted_by(count);\n-};\n-\n extern const struct xattr_handler ext4_xattr_user_handler;\n extern const struct xattr_handler ext4_xattr_trusted_handler;\n extern const struct xattr_handler ext4_xattr_security_handler;\n@@ -187,9 +182,9 @@ extern int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,\n \t\t\t\tbool is_create);\n \n extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,\n-\t\t\t\t struct ext4_xattr_inode_array **array,\n \t\t\t\t int extra_credits);\n-extern void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *array);\n+extern void ext4_init_ea_inode_work(struct ext4_sb_info *sbi);\n+extern void ext4_put_ea_inode(struct inode *inode);\n \n extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,\n \t\t\t struct ext4_inode *raw_inode, handle_t *handle);\ndiff --git a/include/linux/fs.h b/include/linux/fs.h\nindex d10897b3a1e350..04f0de78fa7a85 100644\n--- a/include/linux/fs.h\n+++ b/include/linux/fs.h\n@@ -2413,6 +2413,19 @@ static inline void super_set_sysfs_name_generic(struct super_block *sb, const ch\n extern void ihold(struct inode * inode);\n extern void iput(struct inode *);\n void iput_not_last(struct inode *);\n+\n+/**\n+ * iput_if_not_last - drop an inode reference only if it is not the last one\n+ * @inode: inode to put\n+ *\n+ * Returns true if the reference was dropped, false if this was the last\n+ * reference and the caller must arrange for final iput() in a safe context.\n+ */\n+static inline bool __must_check iput_if_not_last(struct inode *inode)\n+{\n+\treturn atomic_add_unless(\u0026inode-\u003ei_count, -1, 1);\n+}\n+\n int inode_update_time(struct inode *inode, enum fs_update_time type,\n \t\tunsigned int flags);\n int generic_update_time(struct inode *inode, enum fs_update_time type,\n"
} |
| 2/1 | 2026/06/30 14:28 | agent | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: {
"EnableConfigs": [
"EXT4_FS"
],
"FocusSymbols": [
"ext4_put_ea_inode",
"ext4_ea_inode_work",
"ext4_xattr_delete_inode",
"ext4_xattr_block_set",
"ext4_xattr_inode_dec_ref_all"
],
"Reasoning": "The patch introduces a new asynchronous mechanism for releasing ext4 Extended Attribute (EA) inodes to avoid lock ordering issues. It replaces the `ext4_xattr_inode_array` with a lockless list and a delayed workqueue (`ext4_ea_inode_work`). This is a functional change in core ext4 xattr handling and should be fuzzed to ensure there are no use-after-free, memory leaks, or race conditions in the new deferred iput logic.",
"WorthFuzzing": true
}Instruction: You are an expert Linux kernel maintainer. Your job is to review a provided patch series and determine if it makes functional changes to the kernel that should be fuzzed. IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in your workspace. Do NOT rely on your internal knowledge of the kernel. You must actively use your code access tools to examine the actual source code and confirm any assumptions. Return WorthFuzzing=false if the patch only contains: - Modifications to Documentation/, Kconfig files, or code comments. - Purely decorative changes, such as logging (e.g., pr_err, printk) or tracepoints. - Changes to numeric constants or macros that do not functionally alter execution flow. - Code paths that are impossible to reach in virtualized environments like GCE or QEMU, even when utilizing software-emulated hardware (e.g., usb gadget, mac80211_hwsim). If it modifies reachable core kernel logic, drivers, or architectures, use your code search tools to verify the code can be executed, then return WorthFuzzing=true. When returning WorthFuzzing=true, you MUST ALSO: 1. Extract any specific kernel functions that should be heavily fuzzed into FocusSymbols. Avoid listing generic hot-path functions to prevent skewed test distributions. 2. Identify any specific CONFIG_ options required to properly test this new/modified feature. Go and look into the Kconfig files and check for ifdefs around the code, do not make assumptions. Do not list too generic configs (we already have them enabled). Only list those that specifically cover the modified code. List them in the EnableConfigs output array, and DO NOT add a '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: For your convenience, here is the diff of the changes:
commit fa619f539b2da48aff58bfdf2032857281dab4cc
Author: syz-cluster <triage@syzkaller.com>
Date: Tue Jun 30 14:28:17 2026 +0000
syz-cluster: applied patch under review
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index b37c136ea3ab33..b9b0ada7774bb4 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1070,8 +1070,14 @@ struct ext4_inode_info {
* between readers of EAs and writers of regular file data, so
* instead we synchronize on xattr_sem when reading or changing
* EAs.
+ *
+ * EA inodes (EXT4_EA_INODE_FL) do not use xattr_sem; they reuse
+ * the space for deferred iput linkage.
*/
- struct rw_semaphore xattr_sem;
+ union {
+ struct rw_semaphore xattr_sem;
+ struct llist_node i_ea_iput_node;
+ };
/*
* Inodes with EXT4_STATE_ORPHAN_FILE use i_orphan_idx. Otherwise
@@ -1770,6 +1776,11 @@ struct ext4_sb_info {
struct ext4_es_stats s_es_stats;
struct mb_cache *s_ea_block_cache;
struct mb_cache *s_ea_inode_cache;
+
+ /* Deferred iput for EA inodes to avoid lock ordering issues */
+ struct llist_head s_ea_inode_to_free;
+ struct delayed_work s_ea_inode_work;
+
spinlock_t s_es_lock ____cacheline_aligned_in_smp;
/* Journal triggers for checksum computation */
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index ce99807c5f5b2c..747c52c232cc03 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -176,7 +176,6 @@ void ext4_evict_inode(struct inode *inode)
* (xattr block freeing), bitmap, group descriptor (inode freeing)
*/
int extra_credits = 6;
- struct ext4_xattr_inode_array *ea_inode_array = NULL;
bool freeze_protected = false;
trace_ext4_evict_inode(inode);
@@ -281,8 +280,7 @@ void ext4_evict_inode(struct inode *inode)
}
/* Remove xattr references. */
- err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array,
- extra_credits);
+ err = ext4_xattr_delete_inode(handle, inode, extra_credits);
if (err) {
ext4_warning(inode->i_sb, "xattr delete (err %d)", err);
stop_handle:
@@ -290,7 +288,6 @@ void ext4_evict_inode(struct inode *inode)
ext4_orphan_del(NULL, inode);
if (freeze_protected)
sb_end_intwrite(inode->i_sb);
- ext4_xattr_inode_array_free(ea_inode_array);
goto no_delete;
}
@@ -320,7 +317,6 @@ void ext4_evict_inode(struct inode *inode)
ext4_journal_stop(handle);
if (freeze_protected)
sb_end_intwrite(inode->i_sb);
- ext4_xattr_inode_array_free(ea_inode_array);
return;
no_delete:
/*
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 245f67d10ded34..3efa5a817bef4f 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1303,6 +1303,8 @@ static void ext4_put_super(struct super_block *sb)
&sb->s_uuid);
ext4_unregister_li_request(sb);
+ /* Drain deferred EA inode iputs while quota is still active. */
+ flush_delayed_work(&sbi->s_ea_inode_work);
ext4_quotas_off(sb, EXT4_MAXQUOTAS);
destroy_workqueue(sbi->rsv_conversion_wq);
@@ -1423,6 +1425,13 @@ static struct inode *ext4_alloc_inode(struct super_block *sb)
memset(&ei->i_dquot, 0, sizeof(ei->i_dquot));
#endif
ei->jinode = NULL;
+ /*
+ * Reinitialize xattr_sem every allocation because EA inodes
+ * share this space with i_ea_iput_node (via union) which may
+ * have overwritten the semaphore when the slab object was
+ * previously used as an EA inode.
+ */
+ init_rwsem(&ei->xattr_sem);
INIT_LIST_HEAD(&ei->i_rsv_conversion_list);
spin_lock_init(&ei->i_completed_io_lock);
ei->i_sync_tid = 0;
@@ -1488,7 +1497,6 @@ static void init_once(void *foo)
struct ext4_inode_info *ei = foo;
INIT_LIST_HEAD(&ei->i_orphan);
- init_rwsem(&ei->xattr_sem);
init_rwsem(&ei->i_data_sem);
inode_init_once(&ei->vfs_inode);
ext4_fc_init_inode(&ei->vfs_inode);
@@ -5497,6 +5505,8 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
ext4_has_feature_orphan_present(sb) ||
ext4_has_feature_journal_needs_recovery(sb));
+ ext4_init_ea_inode_work(sbi);
+
if (ext4_has_feature_mmp(sb) && !sb_rdonly(sb)) {
err = ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block));
if (err)
@@ -5747,6 +5757,8 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
return 0;
failed_mount9:
+ /* Drain deferred EA inode iputs before quota shutdown */
+ flush_delayed_work(&sbi->s_ea_inode_work);
ext4_quotas_off(sb, EXT4_MAXQUOTAS);
failed_mount8: __maybe_unused
ext4_release_orphan_info(sb);
@@ -5767,6 +5779,8 @@ failed_mount8: __maybe_unused
if (EXT4_SB(sb)->rsv_conversion_wq)
destroy_workqueue(EXT4_SB(sb)->rsv_conversion_wq);
failed_mount_wq:
+ /* Drain deferred EA inode iputs before freeing structures */
+ flush_delayed_work(&sbi->s_ea_inode_work);
ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
sbi->s_ea_inode_cache = NULL;
@@ -5777,6 +5791,8 @@ failed_mount8: __maybe_unused
ext4_journal_destroy(sbi, sbi->s_journal);
}
failed_mount3a:
+ /* Drain deferred EA inode iputs from journal replay */
+ flush_delayed_work(&sbi->s_ea_inode_work);
ext4_es_unregister_shrinker(sbi);
failed_mount3:
/* flush s_sb_upd_work before sbi destroy */
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 982a1f831e2282..4ae6ce1115660e 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -114,10 +114,6 @@ const struct xattr_handler * const ext4_xattr_handlers[] = {
#define EA_INODE_CACHE(inode) (((struct ext4_sb_info *) \
inode->i_sb->s_fs_info)->s_ea_inode_cache)
-static int
-ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
- struct inode *inode);
-
#ifdef CONFIG_LOCKDEP
void ext4_xattr_inode_set_class(struct inode *ea_inode)
{
@@ -567,7 +563,7 @@ ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry,
ea_inode->i_ino, true /* reusable */);
}
out:
- iput(ea_inode);
+ ext4_put_ea_inode(ea_inode);
return err;
}
@@ -1104,10 +1100,10 @@ static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
err = ext4_xattr_inode_inc_ref(handle, ea_inode);
if (err) {
ext4_warning_inode(ea_inode, "inc ref error %d", err);
- iput(ea_inode);
+ ext4_put_ea_inode(ea_inode);
goto cleanup;
}
- iput(ea_inode);
+ ext4_put_ea_inode(ea_inode);
}
return 0;
@@ -1133,7 +1129,7 @@ static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
if (err)
ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
err);
- iput(ea_inode);
+ ext4_put_ea_inode(ea_inode);
}
return saved_err;
}
@@ -1160,7 +1156,6 @@ static void
ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
struct buffer_head *bh,
struct ext4_xattr_entry *first, bool block_csum,
- struct ext4_xattr_inode_array **ea_inode_array,
int extra_credits, bool skip_quota)
{
struct inode *ea_inode;
@@ -1197,14 +1192,6 @@ ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
if (err)
continue;
- err = ext4_expand_inode_array(ea_inode_array, ea_inode);
- if (err) {
- ext4_warning_inode(ea_inode,
- "Expand inode array err=%d", err);
- iput(ea_inode);
- continue;
- }
-
err = ext4_journal_ensure_credits_fn(handle, credits, credits,
ext4_free_metadata_revoke_credits(parent->i_sb, 1),
ext4_xattr_restart_fn(handle, parent, bh, block_csum,
@@ -1212,6 +1199,7 @@ ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
if (err < 0) {
ext4_warning_inode(ea_inode, "Ensure credits err=%d",
err);
+ ext4_put_ea_inode(ea_inode);
continue;
}
if (err > 0) {
@@ -1221,6 +1209,7 @@ ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
ext4_warning_inode(ea_inode,
"Re-get write access err=%d",
err);
+ ext4_put_ea_inode(ea_inode);
continue;
}
}
@@ -1229,6 +1218,7 @@ ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
if (err) {
ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
err);
+ ext4_put_ea_inode(ea_inode);
continue;
}
@@ -1245,6 +1235,7 @@ ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
entry->e_value_inum = 0;
entry->e_value_size = 0;
+ ext4_put_ea_inode(ea_inode);
dirty = true;
}
@@ -1271,7 +1262,6 @@ ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
static void
ext4_xattr_release_block(handle_t *handle, struct inode *inode,
struct buffer_head *bh,
- struct ext4_xattr_inode_array **ea_inode_array,
int extra_credits)
{
struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
@@ -1313,7 +1303,6 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,
ext4_xattr_inode_dec_ref_all(handle, inode, bh,
BFIRST(bh),
true /* block_csum */,
- ea_inode_array,
extra_credits,
true /* skip_quota */);
ext4_free_blocks(handle, inode, bh, 0, 1,
@@ -1505,7 +1494,7 @@ static struct inode *ext4_xattr_inode_create(handle_t *handle,
if (ext4_xattr_inode_dec_ref(handle, ea_inode))
ext4_warning_inode(ea_inode,
"cleanup dec ref error %d", err);
- iput(ea_inode);
+ ext4_put_ea_inode(ea_inode);
return ERR_PTR(err);
}
@@ -1564,7 +1553,7 @@ ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
kvfree(ea_data);
return ea_inode;
}
- iput(ea_inode);
+ ext4_put_ea_inode(ea_inode);
next_entry:
ce = mb_cache_entry_find_next(ea_inode_cache, ce);
}
@@ -1615,7 +1604,7 @@ static struct inode *ext4_xattr_inode_lookup_create(handle_t *handle,
ea_inode->i_ino, true /* reusable */);
return ea_inode;
out_err:
- iput(ea_inode);
+ ext4_put_ea_inode(ea_inode);
ext4_xattr_inode_free_quota(inode, NULL, value_len);
return ERR_PTR(err);
}
@@ -1848,7 +1837,7 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
ret = 0;
out:
- iput(old_ea_inode);
+ ext4_put_ea_inode(old_ea_inode);
return ret;
}
@@ -2010,7 +1999,7 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
old_ea_inode_quota = le32_to_cpu(
s->here->e_value_size);
}
- iput(tmp_inode);
+ ext4_put_ea_inode(tmp_inode);
s->here->e_value_inum = 0;
s->here->e_value_size = 0;
@@ -2150,7 +2139,7 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
ext4_warning_inode(ea_inode,
"dec ref error=%d",
error);
- iput(ea_inode);
+ ext4_put_ea_inode(ea_inode);
ea_inode = NULL;
}
@@ -2182,12 +2171,8 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
/* Drop the previous xattr block. */
if (bs->bh && bs->bh != new_bh) {
- struct ext4_xattr_inode_array *ea_inode_array = NULL;
-
ext4_xattr_release_block(handle, inode, bs->bh,
- &ea_inode_array,
0 /* extra_credits */);
- ext4_xattr_inode_array_free(ea_inode_array);
}
error = 0;
@@ -2203,7 +2188,7 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
ext4_xattr_inode_free_quota(inode, ea_inode,
i_size_read(ea_inode));
}
- iput(ea_inode);
+ ext4_put_ea_inode(ea_inode);
}
if (ce)
mb_cache_entry_put(ea_block_cache, ce);
@@ -2285,7 +2270,7 @@ int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
ext4_xattr_inode_free_quota(inode, ea_inode,
i_size_read(ea_inode));
- iput(ea_inode);
+ ext4_put_ea_inode(ea_inode);
}
return error;
}
@@ -2297,7 +2282,7 @@ int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
header->h_magic = cpu_to_le32(0);
ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
}
- iput(ea_inode);
+ ext4_put_ea_inode(ea_inode);
return 0;
}
@@ -2863,46 +2848,6 @@ int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
return error;
}
-#define EIA_INCR 16 /* must be 2^n */
-#define EIA_MASK (EIA_INCR - 1)
-
-/* Add the large xattr @inode into @ea_inode_array for deferred iput().
- * If @ea_inode_array is new or full it will be grown and the old
- * contents copied over.
- */
-static int
-ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
- struct inode *inode)
-{
- if (*ea_inode_array == NULL) {
- /*
- * Start with 15 inodes, so it fits into a power-of-two size.
- */
- (*ea_inode_array) = kmalloc_flex(**ea_inode_array, inodes,
- EIA_MASK, GFP_NOFS);
- if (*ea_inode_array == NULL)
- return -ENOMEM;
- (*ea_inode_array)->count = 0;
- } else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
- /* expand the array once all 15 + n * 16 slots are full */
- struct ext4_xattr_inode_array *new_array = NULL;
-
- new_array = kmalloc_flex(**ea_inode_array, inodes,
- (*ea_inode_array)->count + EIA_INCR,
- GFP_NOFS);
- if (new_array == NULL)
- return -ENOMEM;
- memcpy(new_array, *ea_inode_array,
- struct_size(*ea_inode_array, inodes,
- (*ea_inode_array)->count));
- kfree(*ea_inode_array);
- *ea_inode_array = new_array;
- }
- (*ea_inode_array)->count++;
- (*ea_inode_array)->inodes[(*ea_inode_array)->count - 1] = inode;
- return 0;
-}
-
/*
* ext4_xattr_delete_inode()
*
@@ -2913,7 +2858,6 @@ ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
* references on xattr block and xattr inodes.
*/
int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
- struct ext4_xattr_inode_array **ea_inode_array,
int extra_credits)
{
struct buffer_head *bh = NULL;
@@ -2952,7 +2896,6 @@ int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
IFIRST(header),
false /* block_csum */,
- ea_inode_array,
extra_credits,
false /* skip_quota */);
}
@@ -2986,12 +2929,12 @@ int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
continue;
ext4_xattr_inode_free_quota(inode, ea_inode,
le32_to_cpu(entry->e_value_size));
- iput(ea_inode);
+ ext4_put_ea_inode(ea_inode);
}
}
- ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
+ ext4_xattr_release_block(handle, inode, bh,
extra_credits);
/*
* Update i_file_acl value in the same transaction that releases
@@ -3013,16 +2956,63 @@ int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
return error;
}
-void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
+/*
+ * Worker function for deferred EA inode iput. Processes all inodes queued
+ * on s_ea_inode_to_free in a context free of xattr_sem/jbd2 handle locks.
+ */
+static void ext4_ea_inode_work(struct work_struct *work)
{
- int idx;
+ struct ext4_sb_info *sbi = container_of(to_delayed_work(work),
+ struct ext4_sb_info,
+ s_ea_inode_work);
+ struct llist_node *node = llist_del_all(&sbi->s_ea_inode_to_free);
- if (ea_inode_array == NULL)
+ while (node) {
+ struct ext4_inode_info *ei = container_of(node,
+ struct ext4_inode_info, i_ea_iput_node);
+ node = node->next;
+ iput(&ei->vfs_inode);
+ }
+}
+
+/*
+ * Release a VFS reference on an EA inode. Must be used instead of iput()
+ * in any context where xattr_sem or a jbd2 handle is held.
+ *
+ * If this is not the last reference, drops it immediately via
+ * iput_if_not_last() with no further action needed.
+ *
+ * If this is the last reference, the inode is linked onto a per-sb
+ * llist via i_ea_iput_node (embedded in ext4_inode_info, sharing space
+ * with the unused xattr_sem) and a delayed worker performs the final
+ * iput() in a clean context.
+ *
+ * Note: while an inode is on s_ea_inode_to_free, the unconsumed i_count
+ * reference (still 1) keeps it in the inode cache, so any concurrent
+ * iget() bumps i_count to >= 2 and iput_if_not_last() will succeed.
+ * Nobody will add the inode a second time until ext4_ea_inode_work()
+ * drops that reference via iput().
+ */
+void ext4_put_ea_inode(struct inode *inode)
+{
+ if (!inode)
+ return;
+ WARN_ON_ONCE(!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL));
+ if (iput_if_not_last(inode))
return;
+ llist_add(&EXT4_I(inode)->i_ea_iput_node,
+ &EXT4_SB(inode->i_sb)->s_ea_inode_to_free);
+ /*
+ * Use a short delay to allow multiple EA inodes to accumulate,
+ * reducing workqueue wakeups when several are released together.
+ */
+ schedule_delayed_work(&EXT4_SB(inode->i_sb)->s_ea_inode_work, 1);
+}
- for (idx = 0; idx < ea_inode_array->count; ++idx)
- iput(ea_inode_array->inodes[idx]);
- kfree(ea_inode_array);
+void ext4_init_ea_inode_work(struct ext4_sb_info *sbi)
+{
+ init_llist_head(&sbi->s_ea_inode_to_free);
+ INIT_DELAYED_WORK(&sbi->s_ea_inode_work, ext4_ea_inode_work);
}
/*
diff --git a/fs/ext4/xattr.h b/fs/ext4/xattr.h
index 1fedf44d4fb65e..821dc6a50e51e7 100644
--- a/fs/ext4/xattr.h
+++ b/fs/ext4/xattr.h
@@ -131,11 +131,6 @@ struct ext4_xattr_ibody_find {
struct ext4_iloc iloc;
};
-struct ext4_xattr_inode_array {
- unsigned int count;
- struct inode *inodes[] __counted_by(count);
-};
-
extern const struct xattr_handler ext4_xattr_user_handler;
extern const struct xattr_handler ext4_xattr_trusted_handler;
extern const struct xattr_handler ext4_xattr_security_handler;
@@ -187,9 +182,9 @@ extern int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
bool is_create);
extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
- struct ext4_xattr_inode_array **array,
int extra_credits);
-extern void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *array);
+extern void ext4_init_ea_inode_work(struct ext4_sb_info *sbi);
+extern void ext4_put_ea_inode(struct inode *inode);
extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
struct ext4_inode *raw_inode, handle_t *handle);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index d10897b3a1e350..04f0de78fa7a85 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2413,6 +2413,19 @@ static inline void super_set_sysfs_name_generic(struct super_block *sb, const ch
extern void ihold(struct inode * inode);
extern void iput(struct inode *);
void iput_not_last(struct inode *);
+
+/**
+ * iput_if_not_last - drop an inode reference only if it is not the last one
+ * @inode: inode to put
+ *
+ * Returns true if the reference was dropped, false if this was the last
+ * reference and the caller must arrange for final iput() in a safe context.
+ */
+static inline bool __must_check iput_if_not_last(struct inode *inode)
+{
+ return atomic_add_unless(&inode->i_count, -1, 1);
+}
+
int inode_update_time(struct inode *inode, enum fs_update_time type,
unsigned int flags);
int generic_update_time(struct inode *inode, enum fs_update_time type,
|
| 3/2 | 2026/06/30 14:28 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 9398 output: 34 thoughts: 442 Thoughts: **Analyzing the Ext4 Xattr Handling Patch** Okay, so I'm looking at this patch for ext4 and it seems pretty significant. It's fundamentally changing how Extended Attribute (EA) inodes are freed. Currently, they use this `ext4_xattr_inode_array`, which is an array, to defer the `iput` calls. Now, it's swapping that out for a lockless list, specifically `llist_head s_ea_inode_to_free`, and a delayed work item, `s_ea_inode_work`. The goal here is clearly to sidestep lock ordering problems, which is a good design choice for improved concurrency. The patch introduces a new function, `ext4_put_ea_inode`, that's key. It uses `iput_if_not_last` and if that's the last reference, adds the inode to the llist and then schedules the work. Also, I see a clever bit with `ext4_inode_info`; the patch unions the `xattr_sem` field with `i_ea_iput_node` because EA inodes don't actually use the `xattr_sem` semaphore, so it's a nice space optimization. This isn't just a minor tweak; it's a core change that affects `ext4_evict_inode`, `ext4_xattr_delete_inode`, `ext4_xattr_block_set`, and others. The introduction of `ext4_ea_inode_work` and `ext4_put_ea_inode` clearly highlights the magnitude of the modification. Now, let's look at the configuration requirements. Since this is ext4, I know we'll need `EXT4_FS`. But, EA inodes are a specific feature. Let's dig deeper. The kernel's configuration options are critical. I'm going to search for `EXT4_EA_INODE_FL` or `EA_INODE` within the ext4 source to find the specific config options. It looks like `CONFIG_EXT4_FS` is the primary one, of course. But are there others? Maybe related options for xattrs, like `CONFIG_EXT4_FS_POSIX_ACL` or `CONFIG_EXT4_FS_SECURITY`? I'm going to quickly check with a grep for `EXT4_EA_INODE_FL` or `ea_inode`, that should show the core conditional. |
| 4/2 | 2026/06/30 14:28 | tool | grepper |
0mArgs:{
"Expression": "EXT4_EA_INODE_FL",
"PathPrefix": "fs/ext4/"
}Results: {
"Output": "fs/ext4/ext4.h=440=struct flex_groups {\n--\nfs/ext4/ext4.h-504-#define EXT4_VERITY_FL\t\t\t0x00100000 /* Verity protected inode */\nfs/ext4/ext4.h:505:#define EXT4_EA_INODE_FL\t 0x00200000 /* Inode used for large EA */\nfs/ext4/ext4.h-506-/* 0x00400000 was formerly EXT4_EOFBLOCKS_FL */\n--\nfs/ext4/ext4.h=1048=struct ext4_inode_info {\n--\nfs/ext4/ext4.h-1073-\t *\nfs/ext4/ext4.h:1074:\t * EA inodes (EXT4_EA_INODE_FL) do not use xattr_sem; they reuse\nfs/ext4/ext4.h-1075-\t * the space for deferred iput linkage.\n--\nfs/ext4/ext4.h=2702=static inline bool ext4_is_quota_file(struct inode *inode)\n--\nfs/ext4/ext4.h-2704-\treturn IS_NOQUOTA(inode) \u0026\u0026\nfs/ext4/ext4.h:2705:\t !(EXT4_I(inode)-\u003ei_flags \u0026 EXT4_EA_INODE_FL);\nfs/ext4/ext4.h-2706-}\n--\nfs/ext4/ialloc.c=933=struct inode *__ext4_new_inode(struct mnt_idmap *idmap,\n--\nfs/ext4/ialloc.c-995-\nfs/ext4/ialloc.c:996:\tif (!(i_flags \u0026 EXT4_EA_INODE_FL)) {\nfs/ext4/ialloc.c-997-\t\terr = fscrypt_prepare_new_inode(dir, inode, \u0026encrypt);\n--\nfs/ext4/ialloc.c-1005-\nfs/ext4/ialloc.c:1006:\tif (!handle \u0026\u0026 sbi-\u003es_journal \u0026\u0026 !(i_flags \u0026 EXT4_EA_INODE_FL)) {\nfs/ext4/ialloc.c-1007-\t\tret2 = ext4_xattr_credits_for_new_inode(dir, mode, encrypt);\n--\nfs/ext4/ialloc.c-1308-\tif (ext4_has_feature_inline_data(sb) \u0026\u0026\nfs/ext4/ialloc.c:1309:\t (!(ei-\u003ei_flags \u0026 (EXT4_DAX_FL|EXT4_EA_INODE_FL)) || S_ISDIR(mode)))\nfs/ext4/ialloc.c-1310-\t\text4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);\n--\nfs/ext4/ialloc.c-1326-\nfs/ext4/ialloc.c:1327:\tif (!(ei-\u003ei_flags \u0026 EXT4_EA_INODE_FL)) {\nfs/ext4/ialloc.c-1328-\t\terr = ext4_init_acl(handle, inode, dir);\n--\nfs/ext4/inode.c=169=void ext4_evict_inode(struct inode *inode)\n--\nfs/ext4/inode.c-184-\nfs/ext4/inode.c:185:\tif (EXT4_I(inode)-\u003ei_flags \u0026 EXT4_EA_INODE_FL)\nfs/ext4/inode.c-186-\t\text4_evict_ea_inode(inode);\n--\nfs/ext4/inode.c=4697=static inline u64 ext4_inode_peek_iversion(const struct inode *inode)\nfs/ext4/inode.c-4698-{\nfs/ext4/inode.c:4699:\tif (unlikely(EXT4_I(inode)-\u003ei_flags \u0026 EXT4_EA_INODE_FL))\nfs/ext4/inode.c-4700-\t\treturn inode_peek_iversion_raw(inode);\n--\nfs/ext4/inode.c=5190=int ext4_get_projid(struct inode *inode, kprojid_t *projid)\n--\nfs/ext4/inode.c-5199- * ext4 has self-managed i_version for ea inodes, it stores the lower 32bit of\nfs/ext4/inode.c:5200: * refcount in i_version, so use raw values if inode has EXT4_EA_INODE_FL flag\nfs/ext4/inode.c-5201- * set.\n--\nfs/ext4/inode.c=5203=static inline void ext4_inode_set_iversion_queried(struct inode *inode, u64 val)\nfs/ext4/inode.c-5204-{\nfs/ext4/inode.c:5205:\tif (unlikely(EXT4_I(inode)-\u003ei_flags \u0026 EXT4_EA_INODE_FL))\nfs/ext4/inode.c-5206-\t\tinode_set_iversion_raw(inode, val);\n--\nfs/ext4/inode.c=5211=static int check_igot_inode(struct inode *inode, ext4_iget_flags flags,\n--\nfs/ext4/inode.c-5216-\tif (flags \u0026 EXT4_IGET_EA_INODE) {\nfs/ext4/inode.c:5217:\t\tif (!(EXT4_I(inode)-\u003ei_flags \u0026 EXT4_EA_INODE_FL)) {\nfs/ext4/inode.c-5218-\t\t\terr_str = \"missing EA_INODE flag\";\n--\nfs/ext4/inode.c-5226-\t} else {\nfs/ext4/inode.c:5227:\t\tif ((EXT4_I(inode)-\u003ei_flags \u0026 EXT4_EA_INODE_FL)) {\nfs/ext4/inode.c-5228-\t\t\t/*\n--\nfs/ext4/xattr.c=1461=static struct inode *ext4_xattr_inode_create(handle_t *handle,\n--\nfs/ext4/xattr.c-1480-\t\t\t\t S_IFREG | 0600, NULL, inode-\u003ei_ino + 1, owner,\nfs/ext4/xattr.c:1481:\t\t\t\t EXT4_EA_INODE_FL);\nfs/ext4/xattr.c-1482-\tif (!IS_ERR(ea_inode)) {\n--\nfs/ext4/xattr.c=2996=void ext4_put_ea_inode(struct inode *inode)\n--\nfs/ext4/xattr.c-2999-\t\treturn;\nfs/ext4/xattr.c:3000:\tWARN_ON_ONCE(!(EXT4_I(inode)-\u003ei_flags \u0026 EXT4_EA_INODE_FL));\nfs/ext4/xattr.c-3001-\tif (iput_if_not_last(inode))\n"
} |
| 5/2 | 2026/06/30 14:28 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 12218 output: 30 thoughts: 84 Thoughts: **Analyzing the Extended Attribute (EA) Inode Handling Patch in ext4** Okay, so this patch is all about tweaking how EA inodes are managed. Right, EA inodes – those are used when we're dealing with extended attributes that are too big to fit in the regular inode structure. This is a pretty fundamental, functional change within ext4. I need to make sure I understand the implications. First, let's see if there are any specific kernel configurations I need to be aware of. Naturally, `CONFIG_EXT4_FS` is the big one, but I should look deeper just to be thorough. I don't want to miss anything. A grep for `CONFIG_EXT4` within `fs/ext4/Kconfig` should give me the complete picture of related configurations. Time to dig in and ensure this patch fits neatly into the existing ecosystem. |
| 6/2 | 2026/06/30 14:28 | tool | grepper |
0mArgs:{
"Expression": "config EXT4",
"PathPrefix": "fs/ext4/Kconfig"
}Results: {
"Output": "fs/ext4/Kconfig-1-# SPDX-License-Identifier: GPL-2.0-only\nfs/ext4/Kconfig:2:config EXT4_FS\nfs/ext4/Kconfig-3-\ttristate \"The Extended 4 (ext4) filesystem\"\n--\nfs/ext4/Kconfig-34-\nfs/ext4/Kconfig:35:config EXT4_USE_FOR_EXT2\nfs/ext4/Kconfig-36-\tbool \"Use ext4 for ext2 file systems\"\n--\nfs/ext4/Kconfig-45-\nfs/ext4/Kconfig:46:config EXT4_FS_POSIX_ACL\nfs/ext4/Kconfig-47-\tbool \"Ext4 POSIX Access Control Lists\"\n--\nfs/ext4/Kconfig-55-\nfs/ext4/Kconfig:56:config EXT4_FS_SECURITY\nfs/ext4/Kconfig-57-\tbool \"Ext4 Security Labels\"\n--\nfs/ext4/Kconfig-67-\nfs/ext4/Kconfig:68:config EXT4_DEBUG\nfs/ext4/Kconfig-69-\tbool \"Ext4 debugging support\"\n--\nfs/ext4/Kconfig-76-\nfs/ext4/Kconfig:77:config EXT4_KUNIT_TESTS\nfs/ext4/Kconfig-78-\ttristate \"KUnit tests for ext4\" if !KUNIT_ALL_TESTS\n"
} |
| 7/2 | 2026/06/30 14:28 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 12882 output: 198 thoughts: 885 Thoughts: **EA Inode Handling: A Fuzzing Target** Alright, let's take a look at this patch. It appears to be related to the `ea_inode` feature in ext4, which, as a reminder, is enabled via `tune2fs -O ea_inode` or `mkfs.ext4 -O ea_inode`, and doesn't require any special Kconfig options other than `EXT4_FS`. Good, that simplifies things from a build perspective. My immediate goal is to identify the key functions this patch modifies that are ripe for fuzzing. It's touching a decent chunk of the xattr code. Specifically, the following functions have caught my eye: `ext4_evict_inode`, `ext4_put_super`, `ext4_alloc_inode`, `__ext4_fill_super`, `ext4_xattr_inode_get`, `ext4_xattr_inode_inc_ref_all`, `ext4_xattr_inode_dec_ref_all`, `ext4_xattr_release_block`, `ext4_xattr_inode_create`, `ext4_xattr_inode_cache_find`, `ext4_xattr_inode_lookup_create`, `ext4_xattr_set_entry`, `ext4_xattr_block_set`, `ext4_xattr_ibody_set`, `ext4_xattr_delete_inode`, *and then the new ones*, `ext4_ea_inode_work`, `ext4_put_ea_inode`, and `ext4_init_ea_inode_work`. That's a lot of surface area! Given that list, I'm thinking we should zero in on the most critical ones and weed out the more general or generic functions. I think we need to concentrate on `ext4_put_ea_inode`, `ext4_ea_inode_work`, `ext4_xattr_delete_inode`, `ext4_xattr_block_set`, and `ext4_xattr_inode_dec_ref_all`. They seem to be the most relevant and likely to expose some interesting issues. Now, let's check the reachability of these functions. `ext4_put_ea_inode` should be easy to target; it looks like it is called from many places within `fs/ext4/xattr.c`. `ext4_ea_inode_work` is, as I suspected, the workqueue function, which makes it particularly interesting because of the asynchronous nature of workqueues. From a configuration perspective, `EXT4_FS` is the only requirement, which is great. Okay, let's just make sure I'm following the logic. The patch is fundamentally changing the way EA inodes are handled during `iput`. It's replacing the old `ext4_xattr_inode_array` approach with a deferred workqueue mechanism for EA inode releasing, specifically to resolve lock ordering problems, likely between `xattr_sem` and `jbd2` handle locks. This definitely warrants fuzzing. The patch is touching core xattr handling so, we need to make sure there are no use-after-free, memory leaks, or race conditions in this new asynchronous `iput` logic. So, here's the final focus. Focus symbols: - `ext4_put_ea_inode` - `ext4_ea_inode_work` - `ext4_xattr_delete_inode` - `ext4_xattr_block_set` - `ext4_xattr_inode_dec_ref_all` Config: - `EXT4_FS` Ready to call set-results. |
| 8/2 | 2026/06/30 14:28 | tool | set-results |
0mArgs:{
"EnableConfigs": [
"EXT4_FS"
],
"FocusSymbols": [
"ext4_put_ea_inode",
"ext4_ea_inode_work",
"ext4_xattr_delete_inode",
"ext4_xattr_block_set",
"ext4_xattr_inode_dec_ref_all"
],
"Reasoning": "The patch introduces a new asynchronous mechanism for releasing ext4 Extended Attribute (EA) inodes to avoid lock ordering issues. It replaces the `ext4_xattr_inode_array` with a lockless list and a delayed workqueue (`ext4_ea_inode_work`). This is a functional change in core ext4 xattr handling and should be fuzzed to ensure there are no use-after-free, memory leaks, or race conditions in the new deferred iput logic.",
"WorthFuzzing": true
}Results: {
"EnableConfigs": [
"EXT4_FS"
],
"FocusSymbols": [
"ext4_put_ea_inode",
"ext4_ea_inode_work",
"ext4_xattr_delete_inode",
"ext4_xattr_block_set",
"ext4_xattr_inode_dec_ref_all"
],
"Reasoning": "The patch introduces a new asynchronous mechanism for releasing ext4 Extended Attribute (EA) inodes to avoid lock ordering issues. It replaces the `ext4_xattr_inode_array` with a lockless list and a delayed workqueue (`ext4_ea_inode_work`). This is a functional change in core ext4 xattr handling and should be fuzzed to ensure there are no use-after-free, memory leaks, or race conditions in the new deferred iput logic.",
"WorthFuzzing": true
} |
| Total Calls | Total Tokens | Avg Tokens | Total Duration (Seconds) | Avg Duration (Seconds) |
|---|
| Total Calls | Total Duration (Seconds) | Avg Duration (Seconds) |
|---|