From: Lu Fengqi <lufq.f...@cn.fujitsu.com>
Introduce a new function check_tree_block_backref() to check if a
backref points to correct referencer.
Signed-off-by: Lu Fengqi <lufq.f...@cn.fujitsu.com>
Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com>
---
cmds-check.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 95 insertions(+)
diff --git a/cmds-check.c b/cmds-check.c
index c301ea1..443b337 100644
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -322,6 +322,8 @@ struct root_item_info {
#define BACKREF_MISSING (1 << 0) /* Backref missing in extent
tree */
#define BACKREF_MISMATCH (1 << 1) /* Backref exists but mismatch */
#define BYTES_UNALIGNED (1 << 2) /* Some bytes are not aligned
*/
+#define REFERENCER_MISSING (1 << 3) /* Referencer not found */
+#define REFERENCER_MISMATCH (1 << 4) /* Referenceer found but mismatch */
static void *print_status_check(void *p)
{
@@ -8791,6 +8793,99 @@ release_out:
return ret;
}
+/*
+ * Check if a tree block backref is valid (points to valid tree block)
+ * if level == -1, level will be resolved
+ * Return >0 for any error found and output error message
+ */
+static int check_tree_block_backref(struct btrfs_fs_info *fs_info, u64 root_id,
+ u64 bytenr, int level)
+{
+ struct btrfs_root *root;
+ struct btrfs_key key;
+ struct btrfs_path path;
+ struct extent_buffer *eb;
+ struct extent_buffer *node;
+ u32 nodesize = btrfs_super_nodesize(fs_info->super_copy);
+ int err = 0;
+ int ret;
+
+ /* Query level for level == -1 special case */
+ if (level == -1)
+ level = query_tree_block_level(fs_info, bytenr);
+ if (level < 0) {
+ err |= REFERENCER_MISSING;
+ goto out;
+ }
+
+ key.objectid = root_id;
+ key.type = BTRFS_ROOT_ITEM_KEY;
+ key.offset = (u64)-1;
+
+ root = btrfs_read_fs_root(fs_info, &key);
+ if (IS_ERR(root)) {
+ err |= REFERENCER_MISSING;
+ goto out;
+ }
+
+ /* Read out the tree block to get item/node key */
+ eb = read_tree_block(root, bytenr, root->nodesize, 0);
+ if (!extent_buffer_uptodate(eb)) {
+ err |= REFERENCER_MISSING;
+ free_extent_buffer(eb);
+ goto out;
+ }
+
+ /* Empty tree, no need to check key */
+ if (!btrfs_header_nritems(eb) && !level) {
+ free_extent_buffer(eb);
+ goto out;
+ }
+
+ if (level)
+ btrfs_node_key_to_cpu(eb, &key, 0);
+ else
+ btrfs_item_key_to_cpu(eb, &key, 0);
+
+ free_extent_buffer(eb);
+
+ btrfs_init_path(&path);
+ /* Search with the first key, to ensure we can reach it */
+ ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
+ if (ret) {
+ err |= REFERENCER_MISSING;
+ goto release_out;
+ }
+
+ node = path.nodes[level];
+ if (btrfs_header_bytenr(node) != bytenr) {
+ error("Extent [%llu %d] referencer bytenr mismatch, wanted:
%llu, have: %llu",
+ bytenr, nodesize, bytenr,
+ btrfs_header_bytenr(node));
+ err |= REFERENCER_MISMATCH;
+ }
+ if (btrfs_header_level(node) != level) {
+ error("Extent [%llu %d] referencer level mismatch, wanted: %d,
have: %d",
+ bytenr, nodesize, level,
+ btrfs_header_level(node));
+ err |= REFERENCER_MISMATCH;
+ }
+
+release_out:
+ btrfs_release_path(&path);
+out:
+ if (err & REFERENCER_MISSING) {
+ if (level < 0)
+ error("Extent [%llu %d] lost referencer(owner: %llu)",
+ bytenr, nodesize, root_id);
+ else
+ error("Extent [%llu %d] lost referencer(owner: %llu,
level: %u)",
+ bytenr, nodesize, root_id, level);
+ }
+
+ return err;
+}
+
static int btrfs_fsck_reinit_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root, int overwrite)
{
--
2.8.2
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