diff options
| author | Jeff Layton <jlayton@kernel.org> | 2023-01-06 16:33:48 +0100 |
|---|---|---|
| committer | Chuck Lever <chuck.lever@oracle.com> | 2023-02-20 15:20:22 +0100 |
| commit | bd6aaf781dae436727928cce514881d3c32758b9 (patch) | |
| tree | 1746c5eacc83d3074a4058b526b159a26a3c5f62 /fs/nfsd | |
| parent | nfsd: allow nfsd_file_get to sanely handle a NULL pointer (diff) | |
| download | linux-bd6aaf781dae436727928cce514881d3c32758b9.tar.xz linux-bd6aaf781dae436727928cce514881d3c32758b9.zip | |
nfsd: fix potential race in nfs4_find_file
The WARN_ON_ONCE check is not terribly useful. It also seems possible
for nfs4_find_file to race with the destruction of an fi_deleg_file
while trying to take a reference to it.
Now that it's safe to pass nfs_get_file a NULL pointer, remove the WARN
and NULL pointer check. Take the fi_lock when fetching fi_deleg_file.
Cc: NeilBrown <neilb@suse.de>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to 'fs/nfsd')
| -rw-r--r-- | fs/nfsd/nfs4state.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 9657dab980cb..7ed723994591 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -6404,23 +6404,26 @@ nfsd4_lookup_stateid(struct nfsd4_compound_state *cstate, static struct nfsd_file * nfs4_find_file(struct nfs4_stid *s, int flags) { + struct nfsd_file *ret = NULL; + if (!s) return NULL; switch (s->sc_type) { case NFS4_DELEG_STID: - if (WARN_ON_ONCE(!s->sc_file->fi_deleg_file)) - return NULL; - return nfsd_file_get(s->sc_file->fi_deleg_file); + spin_lock(&s->sc_file->fi_lock); + ret = nfsd_file_get(s->sc_file->fi_deleg_file); + spin_unlock(&s->sc_file->fi_lock); + break; case NFS4_OPEN_STID: case NFS4_LOCK_STID: if (flags & RD_STATE) - return find_readable_file(s->sc_file); + ret = find_readable_file(s->sc_file); else - return find_writeable_file(s->sc_file); + ret = find_writeable_file(s->sc_file); } - return NULL; + return ret; } static __be32 |