| From f78233dd44a110c574fe760ad6f9c1e8741a0d00 Mon Sep 17 00:00:00 2001 |
| From: Sachin Prabhu <sprabhu@redhat.com> |
| Date: Sat, 13 Mar 2010 09:03:55 -0600 |
| Subject: 9p: Skip check for mandatory locks when unlocking |
| |
| From: Sachin Prabhu <sprabhu@redhat.com> |
| |
| commit f78233dd44a110c574fe760ad6f9c1e8741a0d00 upstream. |
| |
| 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> |
| Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com> |
| Cc: maximilian attems <max@stro.at> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| fs/9p/vfs_file.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/fs/9p/vfs_file.c |
| +++ b/fs/9p/vfs_file.c |
| @@ -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) { |
