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Commit b1785427 authored by Yan's avatar Yan Committed by Chris Mason
Browse files

Fix for btrfs_find_free_objectid 



btrfs_find_free_objectid may return a used objectid due to arithmetic
underflow. This bug may happen when parameter 'root' is tree root,  so
it may cause serious problems when creating snapshot or sub-volume.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent e18e4809

fs/btrfs/inode-map.c

+1 −3
Original line number Diff line number Diff line
@@ -62,7 +62,6 @@ int btrfs_find_free_objectid(struct btrfs_trans_handle *trans, 
	struct btrfs_path *path;

	struct btrfs_key key;

	int ret;

	u64 hole_size = 0;

	int slot = 0;

	u64 last_ino = 0;

	int start_found;
@@ -109,8 +108,7 @@ int btrfs_find_free_objectid(struct btrfs_trans_handle *trans, 
			if (start_found) {

				if (last_ino < search_start)

					last_ino = search_start;

				hole_size = key.objectid - last_ino;

				if (hole_size > 0) {

				if (key.objectid > last_ino) {

					*objectid = last_ino;

					goto found;

				}