Record highest inode number before inode repair.
This is especially important for corrupted leaf case.
Under that case, if use btrfs_find_free_objectid, it may find a ino
existing in corrupted leaf but dropped by btree_recover.
If that happens, created dir will be referenced incorrectly since there
may be inode_ref or dir_index/item refers to it.
So we must record the highest inode number according to the inode_cache.
Inode_cache is OK since when a inode_ref or dir_index/item is found even
the referenced source is not found, it will be created.
If we record the highest inode number of inode_cache, and use
highest_inode + 1 as 'lost+found' dir, it will ensure the newly created
dir not conflicting with any possible inode.
This provides the basis for nlink or inode rebuild for repairing btrfs
with leaf/node corruption.
Signed-off-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
---
Changelog:
v4:
Newly introduced.
---
cmds-check.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/cmds-check.c b/cmds-check.c
index 9fc1410..1f35cc2 100644
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -1927,6 +1927,21 @@ static int check_inode_recs(struct btrfs_root *root,
}
/*
+ * We need to record the highest inode number for later 'lost+found'
+ * dir creation.
+ * We must select a ino not used/refered by any existing inode, or
+ * 'lost+found' ino may be a missing ino in a corrupted leaf,
+ * this may cause 'lost+found' dir has wrong nlinks.
+ */
+ cache = last_cache_extent(inode_cache);
+ if (cache) {
+ node = container_of(cache, struct ptr_node, cache);
+ rec = node->data;
+ if (rec->ino > root->highest_inode)
+ root->highest_inode = rec->ino;
+ }
+
+ /*
* We need to repair backrefs first because we could change some of the
* errors in the inode recs.
*
--
2.1.3
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