From 449231d6ddf50ca46b7fb2f76ecf790135222913 Mon Sep 17 00:00:00 2001 From: Olaf Kirch Date: Thu, 25 Aug 2005 16:25:35 -0700 Subject: [PATCH] From: Olaf Kirch [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: Olaf Kirch Signed-off-by: Trond Myklebust --- fs/locks.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/fs/locks.c b/fs/locks.c index f7daa5f48949..7eb1d77b9204 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -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