If a file's DIR_ITEM key is invalid (due to memory errors) and gets
written to disk, a future lookup_path can end up with kernel panic due
to BUG_ON().
This gets rid of the BUG_ON(), meanwhile output the corrupted key and
return ENOENT if it's invalid.
Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
---
The diff doesn't show the logic well, 'goto out_err' will return with
assigning 0 to location->objectid, and the caller already has a check
for (location->objectid == 0) to return -ENOENT.
fs/btrfs/inode.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index d94e3f6..916cdc9 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5500,6 +5500,14 @@ static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
goto out_err;
btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
+ if (location->type != BTRFS_INODE_ITEM_KEY &&
+ location->type != BTRFS_ROOT_ITEM_KEY) {
+ btrfs_warn(root->fs_info,
+ "%s gets something invalid in DIR_ITEM (name %s, directory ino %llu, location(%llu %u %llu))",
+ __func__, name, btrfs_ino(BTRFS_I(dir)),
+ location->objectid, location->type, location->offset);
+ goto out_err;
+ }
out:
btrfs_free_path(path);
return ret;
@@ -5816,8 +5824,6 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
return inode;
}
- BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
-
index = srcu_read_lock(&fs_info->subvol_srcu);
ret = fixup_tree_root_location(fs_info, dir, dentry,
&location, &sub_root);
--
2.9.4
--
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