diff mbox series

[4/6] btrfs: wake up async_delalloc_pages waiters after submit

Message ID 54425f6e0ece01f5d579e1bcc0aab22a988c301f.1624894102.git.josef@toxicpanda.com (mailing list archive)
State New
Headers show
Series ENOSPC delalloc flushing fixes | expand

Commit Message

Josef Bacik June 28, 2021, 3:37 p.m. UTC
We use the async_delalloc_pages mechanism to make sure that we've
completed our async work before trying to continue our delalloc
flushing.  The reason for this is we need to see any ordered extents
that were created by our delalloc flushing.  However we're waking up
before we do the submit work, which is before we create the ordered
extents.  This is a pretty wide race window where we could potentially
think there are no ordered extents and thus exit shrink_delalloc
prematurely.  Fix this by waking us up after we've done the work to
create ordered extents.

cc: stable@vger.kernel.org
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 fs/btrfs/inode.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index b1f02e3fea5d..e388153c4ae4 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1290,11 +1290,6 @@  static noinline void async_cow_submit(struct btrfs_work *work)
 	nr_pages = (async_chunk->end - async_chunk->start + PAGE_SIZE) >>
 		PAGE_SHIFT;
 
-	/* atomic_sub_return implies a barrier */
-	if (atomic_sub_return(nr_pages, &fs_info->async_delalloc_pages) <
-	    5 * SZ_1M)
-		cond_wake_up_nomb(&fs_info->async_submit_wait);
-
 	/*
 	 * ->inode could be NULL if async_chunk_start has failed to compress,
 	 * in which case we don't have anything to submit, yet we need to
@@ -1303,6 +1298,11 @@  static noinline void async_cow_submit(struct btrfs_work *work)
 	 */
 	if (async_chunk->inode)
 		submit_compressed_extents(async_chunk);
+
+	/* atomic_sub_return implies a barrier */
+	if (atomic_sub_return(nr_pages, &fs_info->async_delalloc_pages) <
+	    5 * SZ_1M)
+		cond_wake_up_nomb(&fs_info->async_submit_wait);
 }
 
 static noinline void async_cow_free(struct btrfs_work *work)