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authorChuck Lever <chuck.lever@oracle.com>2023-11-19 20:17:11 -0500
committerChuck Lever <chuck.lever@oracle.com>2024-01-07 17:54:25 -0500
commita853ed552545e116cf9b197b8c3c5cec80077f1e (patch)
tree23d81bb342f0171bfe0c67b24cd8703ff522775d /fs
parentd0ab8b649ba7636d181605e31bf3e42b0784bc67 (diff)
NFSD: Document lack of f_pos_lock in nfsd_readdir()
Al Viro notes that normal system calls hold f_pos_lock when calling ->iterate_shared and ->llseek; however nfsd_readdir() does not take that mutex when calling these methods. It should be safe however because the struct file acquired by nfsd_readdir() is not visible to other threads. Reviewed-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/nfsd/vfs.c20
1 files changed, 17 insertions, 3 deletions
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index e01e4e2acbd9..c260cbfa8176 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -2102,9 +2102,23 @@ static __be32 nfsd_buffered_readdir(struct file *file, struct svc_fh *fhp,
return cdp->err;
}
-/*
- * Read entries from a directory.
- * The NFSv3/4 verifier we ignore for now.
+/**
+ * nfsd_readdir - Read entries from a directory
+ * @rqstp: RPC transaction context
+ * @fhp: NFS file handle of directory to be read
+ * @offsetp: OUT: seek offset of final entry that was read
+ * @cdp: OUT: an eof error value
+ * @func: entry filler actor
+ *
+ * This implementation ignores the NFSv3/4 verifier cookie.
+ *
+ * NB: normal system calls hold file->f_pos_lock when calling
+ * ->iterate_shared and ->llseek, but nfsd_readdir() does not.
+ * Because the struct file acquired here is not visible to other
+ * threads, it's internal state does not need mutex protection.
+ *
+ * Returns nfs_ok on success, otherwise an nfsstat code is
+ * returned.
*/
__be32
nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp,