Commit f78233dd authored by Sachin Prabhu's avatar Sachin Prabhu Committed by Eric Van Hensbergen
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9p: Skip check for mandatory locks when unlocking

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


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

v9fs_file_lock() should skip the check for mandatory locks when
unlocking a file.

Signed-off-by: default avatarSachin Prabhu <>
Signed-off-by: default avatarEric Van Hensbergen <>
parent fc0f2961
......@@ -114,7 +114,7 @@ static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
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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