Btrfs: Data ordered fixes

* In btrfs_delete_inode, wait for ordered extents after calling
truncate_inode_pages.  This is much faster, and more correct

* Properly clear our the PageChecked bit everywhere we redirty the page.

* Change the writepage fixup handler to lock the page range and check to
see if an ordered extent had been inserted since the improperly dirtied
page was discovered

* Wait for ordered extents outside the transaction.  This isn't required
for locking rules but does improve transaction latencies

* Reduce contention on the alloc_mutex by dropping it while incrementing
refs on a node/leaf and while dropping refs on a leaf.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index eccdb9562ba8..591a30208acd 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -75,6 +75,7 @@ static void btrfs_drop_pages(struct page **pages, size_t num_pages)
         for (i = 0; i < num_pages; i++) {
                 if (!pages[i])
                         break;
+                ClearPageChecked(pages[i]);
                 unlock_page(pages[i]);
                 mark_page_accessed(pages[i]);
                 page_cache_release(pages[i]);