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authorArne Jansen <sensille@gmx.net>2011-06-10 13:55:54 +0200
committerArne Jansen <sensille@gmx.net>2011-10-02 08:48:44 +0200
commit4bb31e928d1a47f5bd046ecb176b8eff7c589fc0 (patch)
tree61693e91f7a179b75cc43f5bcb504d50a342ecb7 /fs/btrfs/disk-io.c
parent7414a03fbf9e75fbbf2a3c16828cd862e572aa44 (diff)
btrfs: hooks for readahead
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. Changes for v2: - eliminate race condition Signed-off-by: Arne Jansen <sensille@gmx.net>
Diffstat (limited to 'fs/btrfs/disk-io.c')
-rw-r--r--fs/btrfs/disk-io.c37
1 files changed, 37 insertions, 0 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index fd28c40e9ec..2151828aa14 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -609,11 +609,47 @@ 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 (test_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags)) {
+ clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags);
+ 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 extent_io_tree *tree;
+ unsigned long len;
+ struct extent_buffer *eb;
+ struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
+
+ tree = &BTRFS_I(page->mapping->host)->io_tree;
+ if (page->private == EXTENT_PAGE_PRIVATE)
+ goto out;
+ if (!page->private)
+ goto out;
+
+ len = page->private >> 2;
+ WARN_ON(len == 0);
+
+ eb = alloc_extent_buffer(tree, start, len, page);
+ if (eb == NULL)
+ goto out;
+
+ if (test_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags)) {
+ clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags);
+ btree_readahead_hook(root, eb, eb->start, -EIO);
+ }
+
+out:
+ 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;
@@ -3166,6 +3202,7 @@ 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,