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btrfs-progs: check: introduce function to query tree block level

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Introduce function query_tree_block_level() to resolve tree block level
by the following method:
1) tree block backref level
2) tree block header level

And only when header level == backref level, and transid matches, it will
return the tree block level.

Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Lu Fengqi 2016-04-23 15:56:50 +08:00 committed by David Sterba
parent b0d360b541
commit ae5271dd52
1 changed files with 76 additions and 0 deletions
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76
cmds-check.c
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@ -8860,6 +8860,82 @@ error:
return err;
}
/*
* Get real tree block level for the case like shared block
* Return >= 0 as tree level
* Return <0 for error
*/
static int query_tree_block_level(struct btrfs_fs_info *fs_info, u64 bytenr)
{
struct extent_buffer *eb;
struct btrfs_path path;
struct btrfs_key key;
struct btrfs_extent_item *ei;
u64 flags;
u64 transid;
u32 nodesize = btrfs_super_nodesize(fs_info->super_copy);
u8 backref_level;
u8 header_level;
int ret;
/* Search extent tree for extent generation and level */
key.objectid = bytenr;
key.type = BTRFS_METADATA_ITEM_KEY;
key.offset = (u64)-1;
btrfs_init_path(&path);
ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, &path, 0, 0);
if (ret < 0)
goto release_out;
ret = btrfs_previous_extent_item(fs_info->extent_root, &path, bytenr);
if (ret < 0)
goto release_out;
if (ret > 0) {
ret = -ENOENT;
goto release_out;
}
btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
ei = btrfs_item_ptr(path.nodes[0], path.slots[0],
struct btrfs_extent_item);
flags = btrfs_extent_flags(path.nodes[0], ei);
if (!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) {
ret = -ENOENT;
goto release_out;
}
/* Get transid for later read_tree_block() check */
transid = btrfs_extent_generation(path.nodes[0], ei);
/* Get backref level as one source */
if (key.type == BTRFS_METADATA_ITEM_KEY) {
backref_level = key.offset;
} else {
struct btrfs_tree_block_info *info;
info = (struct btrfs_tree_block_info *)(ei + 1);
backref_level = btrfs_tree_block_level(path.nodes[0], info);
}
btrfs_release_path(&path);
/* Get level from tree block as an alternative source */
eb = read_tree_block_fs_info(fs_info, bytenr, nodesize, transid);
if (!extent_buffer_uptodate(eb)) {
free_extent_buffer(eb);
return -EIO;
}
header_level = btrfs_header_level(eb);
free_extent_buffer(eb);
if (header_level != backref_level)
return -EIO;
return header_level;
release_out:
btrfs_release_path(&path);
return ret;
}
static int btrfs_fsck_reinit_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root, int overwrite)
{