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btrfs-progs: Record highest inode number before repair. 

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@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
master
Qu Wenruo 2014-12-09 16:27:24 +08:00 committed by David Sterba
parent 378eacf815
commit ed3a206c8f
1 changed files with 15 additions and 0 deletions
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15
cmds-check.c
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@ -1926,6 +1926,21 @@ static int check_inode_recs(struct btrfs_root *root,
return 0;
}
/*
* 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.