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authorArnd Bergmann <arnd@arndb.de>2010-09-18 15:09:31 +0200
committerArnd Bergmann <arnd@arndb.de>2010-10-05 11:02:04 +0200
commitb89f432133851a01c0d28822f11cbdcc15781a75 (patch)
treea3e9ba638a9b746985148f4525335d360ec7da56 /fs/gfs2
parent2e54eb96e2c801f33d95b5dade15212ac4d6c4a5 (diff)
fs/locks.c: prepare for BKL removal
This prepares the removal of the big kernel lock from the file locking code. We still use the BKL as long as fs/lockd uses it and ceph might sleep, but we can flip the definition to a private spinlock as soon as that's done. All users outside of fs/lockd get converted to use lock_flocks() instead of lock_kernel() where appropriate. Based on an earlier patch to use a spinlock from Matthew Wilcox, who has attempted this a few times before, the earliest patch from over 10 years ago turned it into a semaphore, which ended up being slower than the BKL and was subsequently reverted. Someone should do some serious performance testing when this becomes a spinlock, since this has caused problems before. Using a spinlock should be at least as good as the BKL in theory, but who knows... Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Matthew Wilcox <willy@linux.intel.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Miklos Szeredi <mszeredi@suse.cz> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Sage Weil <sage@newdream.net> Cc: linux-kernel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org
Diffstat (limited to 'fs/gfs2')
-rw-r--r--fs/gfs2/file.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 4edd662c8232..8fcfefb96077 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -620,6 +620,8 @@ static ssize_t gfs2_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
* cluster; until we do, disable leases (by just returning -EINVAL),
* unless the administrator has requested purely local locking.
*
+ * Locking: called under lock_flocks
+ *
* Returns: errno
*/