From: Chuck Lever The hard-coded MSDOS_SUPER_MAGIC check in nfsd3_proc_pathconf() only recognizes FAT filesystems as case-insensitive. Modern filesystems like F2FS, exFAT, and CIFS support case-insensitive directories, but NFSv3 clients cannot discover this capability. Query the export's actual case behavior through ->fileattr_get instead. This allows NFSv3 clients to correctly handle case sensitivity for any filesystem that implements the fileattr interface. Filesystems without ->fileattr_get continue to report the default POSIX behavior (case-sensitive, case-preserving). This change depends on the earlier "fat: Implement fileattr_get for case sensitivity" patch in this series, which ensures FAT filesystems report their case behavior correctly via the fileattr interface. Reviewed-by: Roland Mainz Signed-off-by: Chuck Lever --- fs/nfsd/nfs3proc.c | 36 +++++++++++++++++++++------ fs/nfsd/vfs.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ fs/nfsd/vfs.h | 3 +++ fs/nfsd/xdr3.h | 4 +-- 4 files changed, 105 insertions(+), 10 deletions(-) diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c index 42adc5461db0..62ebc65b8af2 100644 --- a/fs/nfsd/nfs3proc.c +++ b/fs/nfsd/nfs3proc.c @@ -710,23 +710,43 @@ nfsd3_proc_pathconf(struct svc_rqst *rqstp) resp->p_name_max = 255; /* at least */ resp->p_no_trunc = 0; resp->p_chown_restricted = 1; - resp->p_case_insensitive = 0; - resp->p_case_preserving = 1; + resp->p_case_insensitive = false; + resp->p_case_preserving = true; resp->status = fh_verify(rqstp, &argp->fh, 0, NFSD_MAY_NOP); if (resp->status == nfs_ok) { struct super_block *sb = argp->fh.fh_dentry->d_sb; + int err; - /* Note that we don't care for remote fs's here */ - switch (sb->s_magic) { - case EXT2_SUPER_MAGIC: + if (sb->s_magic == EXT2_SUPER_MAGIC) { resp->p_link_max = EXT2_LINK_MAX; resp->p_name_max = EXT2_NAME_LEN; + } + + err = nfsd_get_case_info(argp->fh.fh_dentry, + &resp->p_case_insensitive, + &resp->p_case_preserving); + /* + * RFC 1813 lists NFS3ERR_STALE, NFS3ERR_BADHANDLE, and + * NFS3ERR_SERVERFAULT as the only PATHCONF errors. + */ + switch (err) { + case 0: + case -EOPNOTSUPP: + /* Both arms leave the output booleans valid. */ break; - case MSDOS_SUPER_MAGIC: - resp->p_case_insensitive = 1; - resp->p_case_preserving = 0; + case -EACCES: + case -EPERM: + /* + * Policy denied the query. Report STALE so the + * handle is unusable without implying a server + * malfunction. + */ + resp->status = nfserr_stale; + break; + default: + resp->status = nfserr_serverfault; break; } } diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index eafdf7b7890f..4bd63d8efbf7 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -32,6 +32,7 @@ #include #include #include +#include #include "xdr3.h" @@ -2891,3 +2892,74 @@ nfsd_permission(struct svc_cred *cred, struct svc_export *exp, return err? nfserrno(err) : 0; } + +/** + * nfsd_get_case_info - get case sensitivity info for a dentry + * @dentry: dentry to query + * @case_insensitive: set to true if the filesystem is case-insensitive + * @case_preserving: set to true if the filesystem preserves case + * + * On casefold-capable filesystems the flag lives on the directory, + * not on its entries, so for a non-directory @dentry the parent is + * queried instead. A directory (including an export root, whose + * parent lies outside the export) is queried as-is so its own + * contents' lookup behavior is reported. + * + * When the filesystem does not expose case-folding state (no + * ->fileattr_get, or the callback returns -EOPNOTSUPP / + * -ENOIOCTLCMD / -ENOTTY / -EINVAL), the outputs are filled with + * POSIX defaults (case-sensitive, case-preserving) on the premise + * that a filesystem with case-folding support wires up + * fileattr_get. + * + * Other errors propagate unmodified (-EACCES, -EPERM from LSM + * hooks; -EIO, -ESTALE, ... from the filesystem). Case-folding + * behavior is a property of the exported filesystem, not of the + * caller's credentials, so silently substituting defaults would + * let the same dentry report POSIX while LSM denies and report + * casefolding once LSM allows -- a client could race against + * silent name collisions on a case-insensitive export. + * + * Return: 0 with outputs filled, -EOPNOTSUPP with outputs filled + * to POSIX defaults, or a negative errno with outputs + * unmodified. + */ +int +nfsd_get_case_info(struct dentry *dentry, bool *case_insensitive, + bool *case_preserving) +{ + struct file_kattr fa = {}; + struct dentry *cd; + bool put = false; + int err; + + if (d_is_dir(dentry)) { + cd = dentry; + } else { + cd = dget_parent(dentry); + put = true; + } + err = vfs_fileattr_get(cd, &fa); + if (put) + dput(cd); + switch (err) { + case 0: + *case_insensitive = fa.fsx_xflags & FS_XFLAG_CASEFOLD; + *case_preserving = + !(fa.fsx_xflags & FS_XFLAG_CASENONPRESERVING); + return 0; + case -EINVAL: + case -ENOTTY: + case -ENOIOCTLCMD: + case -EOPNOTSUPP: + /* + * Filesystem does not expose case state. + * Report POSIX defaults. + */ + *case_insensitive = false; + *case_preserving = true; + return -EOPNOTSUPP; + default: + return err; + } +} diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h index 702a844f2106..e09ea04a51b9 100644 --- a/fs/nfsd/vfs.h +++ b/fs/nfsd/vfs.h @@ -156,6 +156,9 @@ __be32 nfsd_readdir(struct svc_rqst *, struct svc_fh *, loff_t *, struct readdir_cd *, nfsd_filldir_t); __be32 nfsd_statfs(struct svc_rqst *, struct svc_fh *, struct kstatfs *, int access); +int nfsd_get_case_info(struct dentry *dentry, + bool *case_insensitive, + bool *case_preserving); __be32 nfsd_permission(struct svc_cred *cred, struct svc_export *exp, struct dentry *dentry, int acc); diff --git a/fs/nfsd/xdr3.h b/fs/nfsd/xdr3.h index 522067b7fd75..a7c9714b0b0e 100644 --- a/fs/nfsd/xdr3.h +++ b/fs/nfsd/xdr3.h @@ -209,8 +209,8 @@ struct nfsd3_pathconfres { __u32 p_name_max; __u32 p_no_trunc; __u32 p_chown_restricted; - __u32 p_case_insensitive; - __u32 p_case_preserving; + bool p_case_insensitive; + bool p_case_preserving; }; struct nfsd3_commitres { -- 2.53.0