diff options
| author | Pavel Shilovsky <pshilovsky@samba.org> | 2013-07-11 11:17:45 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-07-21 18:21:21 -0700 |
| commit | 059a1671f28c977fe69a0f86eeb0fa2084fdb3dd (patch) | |
| tree | d3f051c00845f9d840bca3b1d6d98a637713e958 /fs | |
| parent | cfe24e4e36ec19a56bac17691f8721ac44050a6f (diff) | |
| download | lwn-059a1671f28c977fe69a0f86eeb0fa2084fdb3dd.tar.gz lwn-059a1671f28c977fe69a0f86eeb0fa2084fdb3dd.zip | |
CIFS: Fix a deadlock when a file is reopened
commit 689c3db4d57a73bee6c5ad7797fce7b54d32a87c upstream.
If we request reading or writing on a file that needs to be
reopened, it causes the deadlock: we are already holding rw
semaphore for reading and then we try to acquire it for writing
in cifs_relock_file. Fix this by acquiring the semaphore for
reading in cifs_relock_file due to we don't make any changes in
locks and don't need a write access.
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/cifs/file.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/fs/cifs/file.c b/fs/cifs/file.c index 48b29d24c9f4..c2934f8701da 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -553,11 +553,10 @@ cifs_relock_file(struct cifsFileInfo *cfile) struct cifs_tcon *tcon = tlink_tcon(cfile->tlink); int rc = 0; - /* we are going to update can_cache_brlcks here - need a write access */ - down_write(&cinode->lock_sem); + down_read(&cinode->lock_sem); if (cinode->can_cache_brlcks) { - /* can cache locks - no need to push them */ - up_write(&cinode->lock_sem); + /* can cache locks - no need to relock */ + up_read(&cinode->lock_sem); return rc; } @@ -568,7 +567,7 @@ cifs_relock_file(struct cifsFileInfo *cfile) else rc = tcon->ses->server->ops->push_mand_locks(cfile); - up_write(&cinode->lock_sem); + up_read(&cinode->lock_sem); return rc; } |