diff options
| author | Jeff Layton <jlayton@poochiereds.net> | 2014-04-30 09:31:47 -0400 |
|---|---|---|
| committer | Steve French <smfrench@gmail.com> | 2014-05-21 10:18:05 -0700 |
| commit | 4f73c7d342d57d065bdbc0995cb56d8d1701b0c0 (patch) | |
| tree | 6933002e316475c879d702ffbb733a24ba4f0561 /fs/cifs/cifsglob.h | |
| parent | e284e53fdea1dfd66e73c239fa190685985ae465 (diff) | |
cifs: fix potential races in cifs_revalidate_mapping
The handling of the CIFS_INO_INVALID_MAPPING flag is racy. It's possible
for two tasks to attempt to revalidate the mapping at the same time. The
first sees that CIFS_INO_INVALID_MAPPING is set. It clears the flag and
then calls invalidate_inode_pages2 to start shooting down the pagecache.
While that's going on, another task checks the flag and sees that it's
clear. It then ends up trusting the pagecache to satisfy a read when it
shouldn't.
Fix this by adding a bitlock to ensure that the clearing of the flag is
atomic with respect to the actual cache invalidation. Also, move the
other existing users of cifs_invalidate_mapping to use a new
cifs_zap_mapping() function that just sets the INVALID_MAPPING bit and
then uses the standard codepath to handle the invalidation.
Signed-off-by: Jeff Layton <jlayton@poochiereds.net>
Signed-off-by: Steve French <smfrench@gmail.com>
Diffstat (limited to 'fs/cifs/cifsglob.h')
| -rw-r--r-- | fs/cifs/cifsglob.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index 69da55b750e7..630e0f4b2c66 100644 --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -1118,6 +1118,7 @@ struct cifsInodeInfo { #define CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2 (2) /* Downgrade oplock to L2 */ #define CIFS_INO_DELETE_PENDING (3) /* delete pending on server */ #define CIFS_INO_INVALID_MAPPING (4) /* pagecache is invalid */ +#define CIFS_INO_LOCK (5) /* lock bit for synchronization */ unsigned long flags; spinlock_t writers_lock; unsigned int writers; /* Number of writers on this inode */ |