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 <sensille@gmx.net>
---
Change in v2:
- fix return value of scrub_enumerate_chunks
Change in v3:
- check return value of btrfs_previous_item
- some error paths did a unplug without a plug
---
fs/btrfs/scrub.c | 57 ++++++++++++++++++++++++++++++++---------------------
1 files changed, 34 insertions(+), 23 deletions(-)
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index df50fd1..d5a4108 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)
--
1.7.3.4
--
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