When the old device has new fsid through btrfs device add -f <dev> our fs_devices list has an alien device in one of the fs_devices. So this is a trigger and not the root cause of the issue. This patch fixes the trigger. By having an alien device in fs_devices, we have two issues so far 1. missing device is not shows as missing in the userland Which is due to cracks in the function btrfs_open_one_device() and hardened by the pending patches in the ml. btrfs: remove identified alien device in open_fs_devices btrfs: remove identified alien btrfs device in open_fs_devices 2. mount of a degraded fs_devices fails Which is due to cracks in the function btrfs_free_extra_devids() and hardened by patch (included in the set). btrfs: include non-missing as a qualifier for the latest_bdev Now the trigger for both of this issue is that there is an alien (does not contain the intended fsid/btrfs_magic) device in the fs_devices. We know a device can be scanned/added through btrfs-control::BTRFS_IOC_SCAN_DEV|BTRFS_IOC_DEVICES_READY or by ioctl::BTRFS_IOC_ADD_DEV And device coming through btrfs-control is checked against the all other devices in btrfs kernel but not coming through BTRFS_IOC_ADD_DEV. This patch checks if the device add is alienating any other scanned device and deletes it. In fact, this patch fixes both the issues 1 and 2 (above) by eliminating the trigger of the issue, but still they have their own patch as well because its the right way to harden the functions and fill the cracks. Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx> Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx> --- v3-rebased: change log updated. fs/btrfs/volumes.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index a67af16d960d..300ee5f0bfa2 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -2665,6 +2665,19 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path /* Update ctime/mtime for libblkid */ update_dev_time(device_path); + + /* + * Now that we have written a new sb into this device, check all other + * fs_devices list if it alienates any scanned device. + */ + mutex_lock(&uuid_mutex); + /* + * Ignore the return as we are successfull in the core task - to added + * the device + */ + btrfs_free_stale_devices(device_path, NULL); + mutex_unlock(&uuid_mutex); + return ret; error_sysfs: -- 2.23.0
