diff options
| author | Dave Kleikamp <shaggy@linux.vnet.ibm.com> | 2009-08-31 17:07:12 +0200 |
|---|---|---|
| committer | Steve French <sfrench@us.ibm.com> | 2009-09-02 00:35:01 +0200 |
| commit | 6ab409b53dcaf28f83d518a6702f904b7cee3f41 (patch) | |
| tree | 050bfb690ac9df049343034681478a5bb174a823 /fs/cifs/cifsglob.h | |
| parent | cifs: protect GlobalOplock_Q with its own spinlock (diff) | |
| download | linux-6ab409b53dcaf28f83d518a6702f904b7cee3f41.tar.xz linux-6ab409b53dcaf28f83d518a6702f904b7cee3f41.zip | |
cifs: Replace wrtPending with a real reference count
Currently, cifs_close() tries to wait until all I/O is complete and then
frees the file private data. If I/O does not completely in a reasonable
amount of time it frees the structure anyway, leaving a potential use-
after-free situation.
This patch changes the wrtPending counter to a complete reference count and
lets the last user free the structure.
Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Tested-by: Shirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Diffstat (limited to 'fs/cifs/cifsglob.h')
| -rw-r--r-- | fs/cifs/cifsglob.h | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index f100399ee05e..6cfc81a32703 100644 --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -351,11 +351,24 @@ struct cifsFileInfo { bool closePend:1; /* file is marked to close */ bool invalidHandle:1; /* file closed via session abend */ bool messageMode:1; /* for pipes: message vs byte mode */ - atomic_t wrtPending; /* handle in use - defer close */ + atomic_t count; /* reference count */ struct mutex fh_mutex; /* prevents reopen race after dead ses*/ struct cifs_search_info srch_inf; }; +/* Take a reference on the file private data */ +static inline void cifsFileInfo_get(struct cifsFileInfo *cifs_file) +{ + atomic_inc(&cifs_file->count); +} + +/* Release a reference on the file private data */ +static inline void cifsFileInfo_put(struct cifsFileInfo *cifs_file) +{ + if (atomic_dec_and_test(&cifs_file->count)) + kfree(cifs_file); +} + /* * One of these for each file inode */ |