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>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
index 6941c22398a6..7dfe0842a6f6 100644
--- a/fs/cifs/cifsacl.c
+++ b/fs/cifs/cifsacl.c
@@ -607,7 +607,7 @@ static struct cifs_ntsd *get_cifs_acl(struct cifs_sb_info *cifs_sb,
                 return get_cifs_acl_by_path(cifs_sb, path, pacllen);
 
         pntsd = get_cifs_acl_by_fid(cifs_sb, open_file->netfid, pacllen);
-        atomic_dec(&open_file->wrtPending);
+        cifsFileInfo_put(open_file);
         return pntsd;
 }
 
@@ -665,7 +665,7 @@ static int set_cifs_acl(struct cifs_ntsd *pnntsd, __u32 acllen,
                 return set_cifs_acl_by_path(cifs_sb, path, pnntsd, acllen);
 
         rc = set_cifs_acl_by_fid(cifs_sb, open_file->netfid, pnntsd, acllen);
-        atomic_dec(&open_file->wrtPending);
+        cifsFileInfo_put(open_file);
         return rc;
 }