[PATCH v3 REBASED 0/3] btrfs: fix issues due to alien device

[Anand Jain <anand.jain@oracle.com>]

v3 REBASED: Based on the latest misc-next. for for-5.8.
   Dropped the following patches as there were concerns about the usage
   of error code -EUCLEAN
	btrfs: remove identified alien device in open_fs_devices
	btrfs: remove identified alien btrfs device in open_fs_devices

   Rmaining 3 patches here have obtained reviewed-by. With this pathset
   the pertaining fstests btrfs/197 and btrfs/198 (which tests 3 bugs)
   would pass as the patch 2/3 fixed a bug and 3/3 fixed the trigger
   of 2 other bugs (patch 1/3 is just a cleanup). Further at the moment
   I am not sure if there is any other trigger where it could again leave
   an alien device in the fs_devices leading to the same/similar bugs.

==== original email ====
v3: Fix alien device is due to wipefs in Patch4.
    Fix a nit in Patch3.
    Patches are reordered.

Alien device is a device in fs_devices list having a different fsid than
the expected fsid or no btrfs_magic. This patch set fixes issues found due
to the same.

Patch1: is a cleanup patch, not related.
Patch2: fixes failing to mount a degraded RAIDs (RAID1/5/6/10), by
	hardening the function btrfs_free_extra_devids().
Patch3: fixes the missing device (due to alien btrfs-device) not missing in
	the userland, by hardening the function btrfs_open_one_device().
Patch4: fixes the missing device (due to alien device) not missing in
	the userland, by returning EUCLEAN in btrfs_read_dev_one_super().
Patch5: eliminates the source of the alien device in the fs_devices.

PS: Fundamentally its wrong approach that btrfs-progs deduces the device
missing state in the userland instead of obtaining it from the kernel.
I remember objecting on the btrfs-progs patch which did that, but still
it got merged, bugs in p3 and p4 are its side effects. I wrote
patches to read device_state from the kernel using ioctl, procfs and
sysfs but it didn't get the due attention till a merger.

Anand Jain (3):
  btrfs: drop useless goto in open_fs_devices
  btrfs: include non-missing as a qualifier for the latest_bdev
  btrfs: free alien device due to device add

 fs/btrfs/volumes.c | 30 ++++++++++++++++++++++--------
 1 file changed, 22 insertions(+), 8 deletions(-)

-- 
2.23.0