* [PATCH] v9fs: Skip check for mandatory locks when unlocking
[not found] <129079056.288181268330011583.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com>
@ 2010-03-11 17:53 ` Sachin Prabhu
0 siblings, 0 replies; only message in thread
From: Sachin Prabhu @ 2010-03-11 17:53 UTC (permalink / raw)
To: Eric Van Hensbergen, Ron Minnich, Latchesar Ionkov
Cc: Steven Whitehouse, linux-kernel
While investigating a bug, I came across a possible bug in v9fs. The problem is similar to the one reported for NFS by ASANO Masahiro in http://lkml.org/lkml/2005/12/21/334.
v9fs_file_lock() will skip locks on file which has mode set to 02666. This is a problem in cases where the mode of the file is changed after a process has obtained a lock on the file. Such a lock will be skipped during unlock and the machine will end up with a BUG in locks_remove_flock().
v9fs_file_lock() should skip the check for mandatory locks when unlocking a file.
Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
diff -up linux-2.6/fs/9p/vfs_file.c.9p linux-2.6/fs/9p/vfs_file.c
--- linux-2.6/fs/9p/vfs_file.c.9p 2010-03-11 17:32:52.000000000 +0000
+++ linux-2.6/fs/9p/vfs_file.c 2010-03-11 17:33:11.000000000 +0000
@@ -114,7 +114,7 @@ static int v9fs_file_lock(struct file *f
P9_DPRINTK(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
/* No mandatory locks */
- if (__mandatory_lock(inode))
+ if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
return -ENOLCK;
if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
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