Commit ff61d17c authored by Miao Xie's avatar Miao Xie Committed by Chris Mason

Btrfs: Fix the problem that the replace destroys the seed filesystem

The seed filesystem was destroyed by the device replace, the reproduce
method is:
 # mkfs.btrfs -f <dev0>
 # btrfstune -S 1 <dev0>
 # mount <dev0> <mnt>
 # btrfs device add <dev1> <mnt>
 # umount <mnt>
 # mount <dev1> <mnt>
 # btrfs replace start -f <dev0> <dev2> <mnt>
 # umount <mnt>
 # mount <dev0> <mnt>

It is because we erase the super block on the seed device. It is wrong,
we should not change anything on the seed device.
Signed-off-by: default avatarMiao Xie <miaox@cn.fujitsu.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.cz>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent 2c91943b
......@@ -1848,8 +1848,12 @@ void btrfs_rm_dev_replace_srcdev(struct btrfs_fs_info *fs_info,
if (srcdev->bdev) {
fs_info->fs_devices->open_devices--;
/* zero out the old super */
btrfs_scratch_superblock(srcdev);
/*
* zero out the old super if it is not writable
* (e.g. seed device)
*/
if (srcdev->writeable)
btrfs_scratch_superblock(srcdev);
}
call_rcu(&srcdev->rcu, free_device);
......
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