@@ -5408,6 +5408,51 @@ static int check_ref_exists(struct btrfs_trans_handle *trans,
return 1;
}
+/*
+ * We may not have an uptodate block, so if we are going to walk down into this
+ * block we need to drop the lock, read it off of the disk, re-lock it and
+ * return to continue dropping the snapshot.
+ */
+static int check_next_block_uptodate(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct walk_control *wc,
+ struct extent_buffer *next)
+{
+ struct btrfs_tree_parent_check check = { 0 };
+ u64 generation;
+ int level = wc->level;
+ int ret;
+
+ btrfs_assert_tree_write_locked(next);
+
+ generation = btrfs_node_ptr_generation(path->nodes[level],
+ path->slots[level]);
+
+ if (btrfs_buffer_uptodate(next, generation, 0))
+ return 0;
+
+ check.level = level - 1;
+ check.transid = generation;
+ check.owner_root = btrfs_root_id(root);
+ check.has_first_key = true;
+ btrfs_node_key_to_cpu(path->nodes[level], &check.first_key,
+ path->slots[level]);
+
+ btrfs_tree_unlock(next);
+ if (level == 1)
+ reada_walk_down(trans, root, wc, path);
+ ret = btrfs_read_extent_buffer(next, &check);
+ if (ret) {
+ free_extent_buffer(next);
+ return ret;
+ }
+ btrfs_tree_lock(next);
+ wc->lookup_info = 1;
+ return 0;
+}
+
+
/*
* helper to process tree block pointer.
*
@@ -5430,7 +5475,6 @@ static noinline int do_walk_down(struct btrfs_trans_handle *trans,
u64 bytenr;
u64 generation;
u64 owner_root = 0;
- struct btrfs_tree_parent_check check = { 0 };
struct btrfs_key key;
struct extent_buffer *next;
int level = wc->level;
@@ -5452,13 +5496,6 @@ static noinline int do_walk_down(struct btrfs_trans_handle *trans,
bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
- check.level = level - 1;
- check.transid = generation;
- check.owner_root = btrfs_root_id(root);
- check.has_first_key = true;
- btrfs_node_key_to_cpu(path->nodes[level], &check.first_key,
- path->slots[level]);
-
next = btrfs_find_create_tree_block(fs_info, bytenr,
btrfs_root_id(root), level - 1);
if (IS_ERR(next))
@@ -5506,18 +5543,9 @@ static noinline int do_walk_down(struct btrfs_trans_handle *trans,
goto skip;
}
- if (!btrfs_buffer_uptodate(next, generation, 0)) {
- btrfs_tree_unlock(next);
- if (level == 1)
- reada_walk_down(trans, root, wc, path);
- ret = btrfs_read_extent_buffer(next, &check);
- if (ret) {
- free_extent_buffer(next);
- return ret;
- }
- btrfs_tree_lock(next);
- wc->lookup_info = 1;
- }
+ ret = check_next_block_uptodate(trans, root, path, wc, next);
+ if (ret)
+ return ret;
level--;
ASSERT(level == btrfs_header_level(next));
do_walk_down() already has a bunch of things going on, and there's a bit of code related to reading in the next eb if we decide we need it. Move this code off into it's own helper to clean up do_walk_down() a little bit. Signed-off-by: Josef Bacik <josef@toxicpanda.com> --- fs/btrfs/extent-tree.c | 68 +++++++++++++++++++++++++++++------------- 1 file changed, 48 insertions(+), 20 deletions(-)