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authorYan Zheng <zheng.yan@oracle.com>2009-07-22 09:59:00 -0400
committerChris Mason <chris.mason@oracle.com>2009-07-22 09:59:00 -0400
commit33c66f430bfa3a033e70470e4c93f967156b696d (patch)
tree5af7edc4564aa3f32033b364495828eb32b690a7 /fs/btrfs/relocation.c
parente457afec60fdbd86b963d36f4a8a9285088c6043 (diff)
Btrfs: fix locking issue in btrfs_find_next_key
When walking up the tree, btrfs_find_next_key assumes the upper level tree block is properly locked. This isn't always true even path->keep_locks is 1. This is because btrfs_find_next_key may advance path->slots[] several times instead of only once. When 'path->slots[level] >= btrfs_header_nritems(path->nodes[level])' is found, we can't guarantee the original value of 'path->slots[level]' is 'btrfs_header_nritems(path->nodes[level]) - 1'. If it's not, the tree block at 'level + 1' isn't locked. This patch fixes the issue by explicitly checking the locking state, re-searching the tree if it's not locked. Signed-off-by: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/relocation.c')
-rw-r--r--fs/btrfs/relocation.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 008397934778..e71264d1c2c9 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -670,6 +670,8 @@ again:
670 err = ret; 670 err = ret;
671 goto out; 671 goto out;
672 } 672 }
673 if (ret > 0 && path2->slots[level] > 0)
674 path2->slots[level]--;
673 675
674 eb = path2->nodes[level]; 676 eb = path2->nodes[level];
675 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) != 677 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
@@ -1609,6 +1611,7 @@ static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
1609 BUG_ON(level == 0); 1611 BUG_ON(level == 0);
1610 path->lowest_level = level; 1612 path->lowest_level = level;
1611 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0); 1613 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
1614 path->lowest_level = 0;
1612 if (ret < 0) { 1615 if (ret < 0) {
1613 btrfs_free_path(path); 1616 btrfs_free_path(path);
1614 return ret; 1617 return ret;