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Commit 56a0e706 authored by Liu Bo's avatar Liu Bo Committed by David Sterba
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Btrfs: bail out gracefully rather than BUG_ON 



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: default avatarLiu Bo <bo.li.liu@oracle.com>
Reported-by: default avatarGuillaume Bouchard <bouchard@mercs-eng.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 619c47f3

fs/btrfs/inode.c

+8 −2
Original line number Diff line number Diff line
@@ -5445,6 +5445,14 @@ 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;
@@ -5761,8 +5769,6 @@ 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);