If replace was suspended by the umount, replace target device is added
to the fs_devices->alloc_list during a later mount.  This is obviously
wrong.  ->is_tgtdev_for_dev_replace is supposed to guard against that,
but ->is_tgtdev_for_dev_replace is (and can only ever be) initialized
*after* everything is opened and fs_devices lists are populated.  Fix
this by checking the devid instead: for replace targets it's always
equal to BTRFS_DEV_REPLACE_DEVID.
Cc: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
                        fs_devices->rotating = 1;
 
                fs_devices->open_devices++;
-               if (device->writeable && !device->is_tgtdev_for_dev_replace) {
+               if (device->writeable &&
+                   device->devid != BTRFS_DEV_REPLACE_DEVID) {
                        fs_devices->rw_devices++;
                        list_add(&device->dev_alloc_list,
                                 &fs_devices->alloc_list);