From: Chuck Lever <chuck.lever@xxxxxxxxxx> 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. Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx> --- fs/nfsd/vfs.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index fbbea7498f02..87a5953c6bf0 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -2109,9 +2109,23 @@ 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,
