Btrfs: Use async helpers to deal with pages that have been improperly dirtied
Higher layers sometimes call set_page_dirty without asking the filesystem
to help. This causes many problems for the data=ordered and cow code.
This commit detects pages that haven't been properly setup for IO and
kicks off an async helper to deal with them.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 3f82a6e..feff16cb 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2050,6 +2050,16 @@
lock_extent(tree, start, page_end, GFP_NOFS);
unlock_start = start;
+ if (tree->ops && tree->ops->writepage_start_hook) {
+ ret = tree->ops->writepage_start_hook(page, start, page_end);
+ if (ret == -EAGAIN) {
+ unlock_extent(tree, start, page_end, GFP_NOFS);
+ redirty_page_for_writepage(wbc, page);
+ unlock_page(page);
+ return 0;
+ }
+ }
+
end = page_end;
if (test_range_bit(tree, start, page_end, EXTENT_DELALLOC, 0)) {
printk("found delalloc bits after lock_extent\n");