Commit 315bed43 authored Sep 13, 2018 by Nikolay Borisov Committed by David Sterba Oct 15, 2018

btrfs: handle error of get_old_root



In btrfs_search_old_slot get_old_root is always used with the assumption
it cannot fail. However, this is not true in rare circumstance it can
fail and return null. This will lead to null point dereference when the
header is read. Fix this by checking the return value and properly
handling NULL by setting ret to -EIO and returning gracefully.

Coverity-id: 1087503
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

parent 28bee489

fs/btrfs/ctree.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -2960,6 +2960,10 @@ int btrfs_search_old_slot(struct btrfs_root root, const struct btrfs_key key,

		again:
		b = get_old_root(root, time_seq);
		if (!b) {
		ret = -EIO;
		goto done;
		}
		level = btrfs_header_level(b);
		p->locks[level] = BTRFS_READ_LOCK;

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