linux-stable/drivers/s390
Stefan Haberland 5e6bdd37c5 s390/dasd: fix data corruption for thin provisioned devices
Devices are formatted in multiple of tracks.
For an Extent Space Efficient (ESE) volume we get errors when accessing
unformatted tracks. In this case the driver either formats the track on
the flight for write requests or returns zero data for read requests.

In case a request spans multiple tracks, the indication of an unformatted
track presented for the first track is incorrectly applied to all tracks
covered by the request. As a result, tracks containing data will be handled
as empty, resulting in zero data being returned on read, or overwriting
existing data with zero on write.

Fix by determining the track that gets the NRF error.
For write requests only format the track that is surely not formatted.
For Read requests all tracks before have returned valid data and should not
be touched.
All tracks after the unformatted track might be formatted or not. Those are
returned to the blocklayer to build a new request.

When using alias devices there is a chance that multiple write requests
trigger a format of the same track which might lead to data loss. Ensure
that a track is formatted only once by maintaining a list of currently
processed tracks.

Fixes: 5e2b17e712 ("s390/dasd: Add dynamic formatting support for ESE volumes")
Cc: stable@vger.kernel.org # 5.3+
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-12 07:24:52 -06:00
..
block s390/dasd: fix data corruption for thin provisioned devices 2020-03-12 07:24:52 -06:00
char compat_ioctl: move tape handling into drivers 2019-10-23 17:23:44 +02:00
cio s390/qdio: fill SL with absolute addresses 2020-02-19 17:26:32 +01:00
crypto s390/pkey/zcrypt: spelling s/crytp/crypt/ 2020-02-17 18:01:57 +01:00
net s390 updates for 5.6-rc3 2020-02-22 10:43:41 -08:00
scsi s390/qdio: fill SBALEs with absolute addresses 2020-02-19 17:26:32 +01:00
virtio virtio/s390: fix race on airq_areas[] 2019-07-26 13:36:18 +02:00
Makefile s390: remove pointless drivers-y in drivers/s390/Makefile 2019-09-16 13:21:51 +02:00