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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 <sensille@gmx.net>
This commit is contained in:
Arne Jansen 2011-06-03 10:09:26 +02:00
parent ad3e34bba4
commit 8c51032f97
1 changed files with 34 additions and 23 deletions
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57
fs/btrfs/scrub.c
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@ -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)