From 8c51032f978bac5bec5dae0c5de4f85db97c1cc9 Mon Sep 17 00:00:00 2001 From: Arne Jansen Date: Fri, 3 Jun 2011 10:09:26 +0200 Subject: btrfs: scrub: errors in tree enumeration due to the semantics of btrfs_search_slot the path can point to an invalid slot when ret > 0. This condition went unnoticed, which in turn could have led to an incomplete scrubbing. Signed-off-by: Arne Jansen --- fs/btrfs/scrub.c | 57 +++++++++++++++++++++++++++++++++----------------------- 1 file changed, 34 insertions(+), 23 deletions(-) (limited to 'fs/btrfs') diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index df50fd1eca8f..d5a4108cedaf 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -804,18 +804,12 @@ static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev, ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) - goto out; - - l = path->nodes[0]; - slot = path->slots[0]; - btrfs_item_key_to_cpu(l, &key, slot); - if (key.objectid != logical) { - ret = btrfs_previous_item(root, path, 0, - BTRFS_EXTENT_ITEM_KEY); - if (ret < 0) - goto out; - } + goto out_noplug; + /* + * we might miss half an extent here, but that doesn't matter, + * as it's only the prefetch + */ while (1) { l = path->nodes[0]; slot = path->slots[0]; @@ -824,7 +818,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev, if (ret == 0) continue; if (ret < 0) - goto out; + goto out_noplug; break; } @@ -906,15 +900,20 @@ again: ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) goto out; - - l = path->nodes[0]; - slot = path->slots[0]; - btrfs_item_key_to_cpu(l, &key, slot); - if (key.objectid != logical) { + if (ret > 0) { ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY); if (ret < 0) goto out; + if (ret > 0) { + /* there's no smaller item, so stick with the + * larger one */ + btrfs_release_path(path); + ret = btrfs_search_slot(NULL, root, &key, + path, 0, 0); + if (ret < 0) + goto out; + } } while (1) { @@ -989,6 +988,7 @@ next: out: blk_finish_plug(&plug); +out_noplug: btrfs_free_path(path); return ret < 0 ? ret : 0; } @@ -1064,8 +1064,15 @@ int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end) while (1) { ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) - goto out; - ret = 0; + break; + if (ret > 0) { + if (path->slots[0] >= + btrfs_header_nritems(path->nodes[0])) { + ret = btrfs_next_leaf(root, path); + if (ret) + break; + } + } l = path->nodes[0]; slot = path->slots[0]; @@ -1075,7 +1082,7 @@ int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end) if (found_key.objectid != sdev->dev->devid) break; - if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY) + if (btrfs_key_type(&found_key) != BTRFS_DEV_EXTENT_KEY) break; if (found_key.offset >= end) @@ -1104,7 +1111,7 @@ int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end) cache = btrfs_lookup_block_group(fs_info, chunk_offset); if (!cache) { ret = -ENOENT; - goto out; + break; } ret = scrub_chunk(sdev, chunk_tree, chunk_objectid, chunk_offset, length); @@ -1116,9 +1123,13 @@ int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end) btrfs_release_path(path); } -out: btrfs_free_path(path); - return ret; + + /* + * ret can still be 1 from search_slot or next_leaf, + * that's not an error + */ + return ret < 0 ? ret : 0; } static noinline_for_stack int scrub_supers(struct scrub_dev *sdev) -- cgit v1.2.3