[v1,4/5] btrfs: hooks for readahead

Commit Message

Arne Jansen May 23, 2011, 12:59 p.m. UTC

This adds the hooks needed for readahead. In the readpage_end_io_hook,
the extent state is checked for the EXTENT_READAHEAD flag. Only in this
case the readahead hook is called, to keep the impact on non-ra as low
as possible.
Additionally, a hook for a failed IO is added, otherwise readahead would
wait indefinitely for the extent to finish.

Signed-off-by: Arne Jansen <[e-mail]>
---
 fs/btrfs/disk-io.c   |   16 ++++++++++++++++
 fs/btrfs/extent_io.c |    2 +-
 2 files changed, 17 insertions(+), 1 deletions(-)

Patch

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 3d4f9c5..7949f30 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -580,11 +580,26 @@  static int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
 	end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
 	end = eb->start + end - 1;
 err:
+	if (state && state->state & EXTENT_READAHEAD)
+		btree_readahead_hook(root, eb, eb->start, ret);
+
 	free_extent_buffer(eb);
 out:
 	return ret;
 }
 
+static int btree_io_failed_hook(struct bio *failed_bio,
+			 struct page *page, u64 start, u64 end,
+			 struct extent_state *state)
+{
+	struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
+
+	if (state && state->state & EXTENT_READAHEAD)
+		btree_readahead_hook(root, NULL, start, -EIO);
+
+	return -EIO;	/* we fixed nothing */
+}
+
 static void end_workqueue_bio(struct bio *bio, int err)
 {
 	struct end_io_wq *end_io_wq = bio->bi_private;
@@ -3192,6 +3207,7 @@  static int btrfs_cleanup_transaction(struct btrfs_root *root)
 static struct extent_io_ops btree_extent_io_ops = {
 	.write_cache_pages_lock_hook = btree_lock_page_hook,
 	.readpage_end_io_hook = btree_readpage_end_io_hook,
+	.readpage_io_failed_hook = btree_io_failed_hook,
 	.submit_bio_hook = btree_submit_bio_hook,
 	/* note we're sharing with inode.c for the merge bio hook */
 	.merge_bio_hook = btrfs_merge_bio_hook,
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index df0bc46..3622230 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1788,7 +1788,7 @@  static void end_bio_extent_readpage(struct bio *bio, int err)
 		if (!uptodate && tree->ops &&
 		    tree->ops->readpage_io_failed_hook) {
 			ret = tree->ops->readpage_io_failed_hook(bio, page,
-							 start, end, NULL);
+							 start, end, state);
 			if (ret == 0) {
 				uptodate =
 					test_bit(BIO_UPTODATE, &bio->bi_flags);