linux-stable.git/drivers/md, branch v5.3.8

dm cache: fix bugs when a GFP_NOWAIT allocation fails

2019-10-29T08:22:39+00:00

commit 13bd677a472d534bf100bab2713efc3f9e3f5978 upstream.

GFP_NOWAIT allocation can fail anytime - it doesn't wait for memory being
available and it fails if the mempool is exhausted and there is not enough
memory.

If we go down this path:
  map_bio -> mg_start -> alloc_migration -> mempool_alloc(GFP_NOWAIT)
we can see that map_bio() doesn't check the return value of mg_start(),
and the bio is leaked.

If we go down this path:
  map_bio -> mg_start -> mg_lock_writes -> alloc_prison_cell ->
  dm_bio_prison_alloc_cell_v2 -> mempool_alloc(GFP_NOWAIT) ->
  mg_lock_writes -> mg_complete
the bio is ended with an error - it is unacceptable because it could
cause filesystem corruption if the machine ran out of memory
temporarily.

Change GFP_NOWAIT to GFP_NOIO, so that the mempool code will properly
wait until memory becomes available. mempool_alloc with GFP_NOIO can't
fail, so remove the code paths that deal with allocation failure.

Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

md/raid0: fix warning message for parameter default_layout

2019-10-29T08:21:50+00:00

[ Upstream commit 3874d73e06c9b9dc15de0b7382fc223986d75571 ]

The message should match the parameter, i.e. raid0.default_layout.

Fixes: c84a1372df92 ("md/raid0: avoid RAID0 data corruption due to layout confusion.")
Cc: NeilBrown 
Reported-by: Ivan Topolsky 
Signed-off-by: Song Liu 
Signed-off-by: Sasha Levin

dm zoned: fix invalid memory access

2019-10-07T17:01:56+00:00

commit 0c8e9c2d668278652af028c3cc068c65f66342f4 upstream.

Commit 75d66ffb48efb30f2dd42f041ba8b39c5b2bd115 ("dm zoned: properly
handle backing device failure") triggers a coverity warning:

dm raid: fix updating of max_discard_sectors limit

2019-10-07T17:01:56+00:00

commit c8156fc77d0796ba2618936dbb3084e769e916c1 upstream.

Unit of 'chunk_size' is byte, instead of sector, so fix it by setting
the queue_limits' max_discard_sectors to rs->md.chunk_sectors.  Also,
rename chunk_size to chunk_size_bytes.

Without this fix, too big max_discard_sectors is applied on the request
queue of dm-raid, finally raid code has to split the bio again.

This re-split done by raid causes the following nested clone_endio:

1) one big bio 'A' is submitted to dm queue, and served as the original
bio

2) one new bio 'B' is cloned from the original bio 'A', and .map()
is run on this bio of 'B', and B's original bio points to 'A'

3) raid code sees that 'B' is too big, and split 'B' and re-submit
the remainded part of 'B' to dm-raid queue via generic_make_request().

4) now dm will handle 'B' as new original bio, then allocate a new
clone bio of 'C' and run .map() on 'C'. Meantime C's original bio
points to 'B'.

5) suppose now 'C' is completed by raid directly, then the following
clone_endio() is called recursively:

	clone_endio(C)
		->clone_endio(B)		#B is original bio of 'C'
			->bio_endio(A)

'A' can be big enough to make hundreds of nested clone_endio(), then
stack can be corrupted easily.

Fixes: 61697a6abd24a ("dm: eliminate 'split_discard_bios' flag from DM target interface")
Cc: stable@vger.kernel.org
Signed-off-by: Ming Lei 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

md/raid0: avoid RAID0 data corruption due to layout confusion.

2019-10-05T13:12:38+00:00

[ Upstream commit c84a1372df929033cb1a0441fb57bd3932f39ac9 ]

If the drives in a RAID0 are not all the same size, the array is
divided into zones.
The first zone covers all drives, to the size of the smallest.
The second zone covers all drives larger than the smallest, up to
the size of the second smallest - etc.

A change in Linux 3.14 unintentionally changed the layout for the
second and subsequent zones.  All the correct data is still stored, but
each chunk may be assigned to a different device than in pre-3.14 kernels.
This can lead to data corruption.

It is not possible to determine what layout to use - it depends which
kernel the data was written by.
So we add a module parameter to allow the old (0) or new (1) layout to be
specified, and refused to assemble an affected array if that parameter is
not set.

Fixes: 20d0189b1012 ("block: Introduce new bio_split()")
cc: stable@vger.kernel.org (3.14+)
Acked-by: Guoqing Jiang 
Signed-off-by: NeilBrown 
Signed-off-by: Song Liu 
Signed-off-by: Sasha Levin

md: only call set_in_sync() when it is expected to succeed.

2019-10-05T13:12:33+00:00

commit 480523feae581ab714ba6610388a3b4619a2f695 upstream.

Since commit 4ad23a976413 ("MD: use per-cpu counter for
writes_pending"), set_in_sync() is substantially more expensive: it
can wait for a full RCU grace period which can be 10s of milliseconds.

So we should only call it when the cost is justified.

md_check_recovery() currently calls set_in_sync() every time it finds
anything to do (on non-external active arrays).  For an array
performing resync or recovery, this will be quite often.
Each call will introduce a delay to the md thread, which can noticeable
affect IO submission latency.

In md_check_recovery() we only need to call set_in_sync() if
'safemode' was non-zero at entry, meaning that there has been not
recent IO.  So we save this "safemode was nonzero" state, and only
call set_in_sync() if it was non-zero.

This measurably reduces mean and maximum IO submission latency during
resync/recovery.

Reported-and-tested-by: Jack Wang 
Fixes: 4ad23a976413 ("MD: use per-cpu counter for writes_pending")
Cc: stable@vger.kernel.org (v4.12+)
Signed-off-by: NeilBrown 
Signed-off-by: Song Liu 
Signed-off-by: Greg Kroah-Hartman

md: don't report active array_state until after revalidate_disk() completes.

2019-10-05T13:12:33+00:00

commit 9d4b45d6af442237560d0bb5502a012baa5234b7 upstream.

Until revalidate_disk() has completed, the size of a new md array will
appear to be zero.
So we shouldn't report, through array_state, that the array is active
until that time.
udev rules check array_state to see if the array is ready.  As soon as
it appear to be zero, fsck can be run.  If it find the size to be
zero, it will fail.

So add a new flag to provide an interlock between do_md_run() and
array_state_show().  This flag is set while do_md_run() is active and
it prevents array_state_show() from reporting that the array is
active.

Before do_md_run() is called, ->pers will be NULL so array is
definitely not active.
After do_md_run() is called, revalidate_disk() will have run and the
array will be completely ready.

We also move various sysfs_notify*() calls out of md_run() into
do_md_run() after MD_NOT_READY is cleared.  This ensure the
information is ready before the notification is sent.

Prior to v4.12, array_state_show() was called with the
mddev->reconfig_mutex held, which provided exclusion with do_md_run().

Note that MD_NOT_READY cleared twice.  This is deliberate to cover
both success and error paths with minimal noise.

Fixes: b7b17c9b67e5 ("md: remove mddev_lock() from md_attr_show()")
Cc: stable@vger.kernel.org (v4.12++)
Signed-off-by: NeilBrown 
Signed-off-by: Song Liu 
Signed-off-by: Greg Kroah-Hartman

md/raid6: Set R5_ReadError when there is read failure on parity disk

2019-10-05T13:12:33+00:00

commit 143f6e733b73051cd22dcb80951c6c929da413ce upstream.

7471fb77ce4d ("md/raid6: Fix anomily when recovering a single device in
RAID6.") avoids rereading P when it can be computed from other members.
However, this misses the chance to re-write the right data to P. This
patch sets R5_ReadError if the re-read fails.

Also, when re-read is skipped, we also missed the chance to reset
rdev->read_errors to 0. It can fail the disk when there are many read
errors on P member disk (other disks don't have read error)

V2: upper layer read request don't read parity/Q data. So there is no
need to consider such situation.

This is Reported-by: kbuild test robot 

Fixes: 7471fb77ce4d ("md/raid6: Fix anomily when recovering a single device in RAID6.")
Cc:  #4.4+
Signed-off-by: Xiao Ni 
Signed-off-by: Song Liu 
Signed-off-by: Greg Kroah-Hartman

blk-mq: add callback of .cleanup_rq

2019-10-05T13:12:16+00:00

[ Upstream commit 226b4fc75c78f9c497c5182d939101b260cfb9f3 ]

SCSI maintains its own driver private data hooked off of each SCSI
request, and the pridate data won't be freed after scsi_queue_rq()
returns BLK_STS_RESOURCE or BLK_STS_DEV_RESOURCE. An upper layer driver
(e.g. dm-rq) may need to retry these SCSI requests, before SCSI has
fully dispatched them, due to a lower level SCSI driver's resource
limitation identified in scsi_queue_rq(). Currently SCSI's per-request
private data is leaked when the upper layer driver (dm-rq) frees and
then retries these requests in response to BLK_STS_RESOURCE or
BLK_STS_DEV_RESOURCE returns from scsi_queue_rq().

This usecase is so specialized that it doesn't warrant training an
existing blk-mq interface (e.g. blk_mq_free_request) to allow SCSI to
account for freeing its driver private data -- doing so would add an
extra branch for handling a special case that all other consumers of
SCSI (and blk-mq) won't ever need to worry about.

So the most pragmatic way forward is to delegate freeing SCSI driver
private data to the upper layer driver (dm-rq).  Do so by adding
new .cleanup_rq callback and calling a new blk_mq_cleanup_rq() method
from dm-rq.  A following commit will implement the .cleanup_rq() hook
in scsi_mq_ops.

Cc: Ewan D. Milne 
Cc: Bart Van Assche 
Cc: Hannes Reinecke 
Cc: Christoph Hellwig 
Cc: Mike Snitzer 
Cc: dm-devel@redhat.com
Cc: 
Fixes: 396eaf21ee17 ("blk-mq: improve DM's blk-mq IO merging via blk_insert_cloned_request feedback")
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

raid5: don't increment read_errors on EILSEQ return

2019-10-05T13:12:08+00:00

[ Upstream commit b76b4715eba0d0ed574f58918b29c1b2f0fa37a8 ]

While MD continues to count read errors returned by the lower layer.
If those errors are -EILSEQ, instead of -EIO, it should NOT increase
the read_errors count.

When RAID6 is set up on dm-integrity target that detects massive
corruption, the leg will be ejected from the array.  Even if the
issue is correctable with a sector re-write and the array has
necessary redundancy to correct it.

The leg is ejected because it runs up the rdev->read_errors beyond
conf->max_nr_stripes.  The return status in dm-drypt when there is
a data integrity error is -EILSEQ (BLK_STS_PROTECTION).

Signed-off-by: Nigel Croxon 
Signed-off-by: Song Liu 
Signed-off-by: Sasha Levin