btrfs-progs: btrfstune: fix a bug which makes unfinished fsid change unrecoverable

This bug is found by making break point after change_fsid_prepare() and
then kill the unfinished change, then try to restore the unfinished fsid
change.

If fsid change is canceled, open_ctree will still fail even with
IGNORE_FSID_MIMATCH open ctree flag, since it can't find device with
mismatched fsid, making it unable to restoring.

Now add ignore_fsid_mismatch judgment in btrfs_find_device() to fix the
bug and allow later restore to work as expected.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>

diff --git a/volumes.c b/volumes.c
index 14ce33e..f7462c5 100644 (file)
--- a/volumes.c
+++ b/volumes.c
@@ -1510,7 +1510,8 @@ struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
        cur_devices = root->fs_info->fs_devices;
        while (cur_devices) {
                if (!fsid ||
-                   !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
+                   (!memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE) ||
+                    root->fs_info->ignore_fsid_mismatch)) {
                        device = __find_device(&cur_devices->devices,
                                               devid, uuid);
                        if (device)