Commit 449231d6 authored by Olaf Kirch's avatar Olaf Kirch Committed by Trond Myklebust
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From: Olaf Kirch <okir@suse.de>


[PATCH] Fix miscompare in __posix_lock_file

 If an application requests the same lock twice, the
 kernel should just leave the existing lock in place.
 Currently, it will install a second lock of the same type.
Signed-off-by: default avatarOlaf Kirch <okir@suse.de>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 20509f1b
......@@ -829,12 +829,16 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request)
/* Detect adjacent or overlapping regions (if same lock type)
*/
if (request->fl_type == fl->fl_type) {
/* In all comparisons of start vs end, use
* "start - 1" rather than "end + 1". If end
* is OFFSET_MAX, end + 1 will become negative.
*/
if (fl->fl_end < request->fl_start - 1)
goto next_lock;
/* If the next lock in the list has entirely bigger
* addresses than the new one, insert the lock here.
*/
if (fl->fl_start > request->fl_end + 1)
if (fl->fl_start - 1 > request->fl_end)
break;
/* If we come here, the new and old lock are of the
......
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