Btrfs: [PATCH] extent_map: add writepage_end_io hook

XFS updates the ondisk inode size only after the data I/O has finished,
so it needs a hook when the writepage end_bio handler has finished.

Might not be worth applying as-is as the per-page callback is very
ineffcient.  What XFS really wants is a callback when writeout of a
whole extent has completed.  This delayed i_size updates scheme might
be worthwile for btrfs aswell, btw.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 162766773a32c0376d99b0c1b60f138271db6095..ab5bde31b6875001bf846eacce6b98a8a864800c 100644 (file)
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -1231,6 +1231,8 @@ static int end_bio_extent_writepage(struct bio *bio,
                        end_page_writeback(page);
                else
                        check_page_writeback(tree, page);
+               if (tree->ops && tree->ops->writepage_end_io_hook)
+                       tree->ops->writepage_end_io_hook(page, start, end);
        } while (bvec >= bio->bi_io_vec);
 
        bio_put(bio);

diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
index da41aca74e0bb644cfe008e928731c48c6285964..40b53ee274fb2d79e45117abed4a7839929ed8b7 100644 (file)
--- a/fs/btrfs/extent_map.h
+++ b/fs/btrfs/extent_map.h
@@ -11,6 +11,7 @@ struct extent_map_ops {
        int (*writepage_io_hook)(struct page *page, u64 start, u64 end);
        int (*readpage_io_hook)(struct page *page, u64 start, u64 end);
        int (*readpage_end_io_hook)(struct page *page, u64 start, u64 end);
+       void (*writepage_end_io_hook)(struct page *page, u64 start, u64 end);
 };
 
 struct extent_map_tree {