diff options
| author | Josef Bacik <jbacik@fusionio.com> | 2012-08-01 15:36:24 -0400 |
|---|---|---|
| committer | Chris Mason <chris.mason@oracle.com> | 2012-08-28 16:53:33 -0400 |
| commit | 66657b318e0e443ada229fccd40c8be86cfebdbf (patch) | |
| tree | bf1334fff93556fbc8d82b26a6d5431fd9e74b5c /fs/btrfs/inode.c | |
| parent | 1fa11e265fa2562fb713171b6a58e72bb7afd276 (diff) | |
Btrfs: barrier before waitqueue_active
We need a barrir before calling waitqueue_active otherwise we will miss
wakeups. So in places that do atomic_dec(); then atomic_read() use
atomic_dec_return() which imply a memory barrier (see memory-barriers.txt)
and then add an explicit memory barrier everywhere else that need them.
Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Diffstat (limited to 'fs/btrfs/inode.c')
| -rw-r--r-- | fs/btrfs/inode.c | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 2d65c52b0944..97baf00b40d1 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -1007,9 +1007,7 @@ static noinline void async_cow_submit(struct btrfs_work *work) nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >> PAGE_CACHE_SHIFT; - atomic_sub(nr_pages, &root->fs_info->async_delalloc_pages); - - if (atomic_read(&root->fs_info->async_delalloc_pages) < + if (atomic_sub_return(nr_pages, &root->fs_info->async_delalloc_pages) < 5 * 1024 * 1024 && waitqueue_active(&root->fs_info->async_submit_wait)) wake_up(&root->fs_info->async_submit_wait); |