From a1317f455ab936a9447f17b08e3e874c27742870 Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Mon, 15 Dec 2014 16:04:42 +0000 Subject: [PATCH] Btrfs: correctly get tree level in tree_backref_for_extent If we are using skinny metadata, the block's tree level is in the offset of the key and not in a btrfs_tree_block_info structure following the extent item (it doesn't exist). Therefore fix it. Besides returning the correct level in the tree, this also prevents reading past the leaf's end in the case where the extent item is the last item in the leaf (eb) and it has only 1 inline reference - this is because sizeof(struct btrfs_tree_block_info) is greater than sizeof(struct btrfs_extent_inline_ref). Got it while running a scrub which produced the following warning: BTRFS: checksum error at logical 42123264 on dev /dev/sde, sector 15840: metadata node (level 24) in tree 5 Signed-off-by: Filipe Manana Reviewed-by: Satoru Takeuchi Signed-off-by: Chris Mason --- fs/btrfs/backref.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index 2d3e32ebfd15..8729cf68d2fe 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -1552,7 +1552,6 @@ int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb, { int ret; int type; - struct btrfs_tree_block_info *info; struct btrfs_extent_inline_ref *eiref; if (*ptr == (unsigned long)-1) @@ -1573,9 +1572,17 @@ int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb, } /* we can treat both ref types equally here */ - info = (struct btrfs_tree_block_info *)(ei + 1); *out_root = btrfs_extent_inline_ref_offset(eb, eiref); - *out_level = btrfs_tree_block_level(eb, info); + + if (key->type == BTRFS_EXTENT_ITEM_KEY) { + struct btrfs_tree_block_info *info; + + info = (struct btrfs_tree_block_info *)(ei + 1); + *out_level = btrfs_tree_block_level(eb, info); + } else { + ASSERT(key->type == BTRFS_METADATA_ITEM_KEY); + *out_level = (u8)key->offset; + } if (ret == 1) *ptr = (unsigned long)-1; -- 2.20.1