linux-toradex.git/drivers/md/raid10.c, branch v4.4.158

md/raid10: fix that replacement cannot complete recovery after reassemble

2018-08-24T11:26:57+00:00

[ Upstream commit bda3153998f3eb2cafa4a6311971143628eacdbc ]

During assemble, the spare marked for replacement is not checked.
conf->fullsync cannot be updated to be 1. As a result, recovery will
treat it as a clean array. All recovering sectors are skipped. Original
device is replaced with the not-recovered spare.

mdadm -C /dev/md0 -l10 -n4 -pn2 /dev/loop[0123]
mdadm /dev/md0 -a /dev/loop4
mdadm /dev/md0 --replace /dev/loop0
mdadm -S /dev/md0 # stop array during recovery

mdadm -A /dev/md0 /dev/loop[01234]

After reassemble, you can see recovery go on, but it completes
immediately. In fact, recovery is not actually processed.

To solve this problem, we just add the missing logics for replacment
spares. (In raid1.c or raid5.c, they have already been checked.)

Reported-by: Alex Chen 
Reviewed-by: Alex Wu 
Reviewed-by: Chung-Chiang Cheng 
Signed-off-by: BingJing Chang 
Signed-off-by: Shaohua Li 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

md raid10: fix NULL deference in handle_write_completed()

2018-05-30T05:48:59+00:00

[ Upstream commit 01a69cab01c184d3786af09e9339311123d63d22 ]

In the case of 'recover', an r10bio with R10BIO_WriteError &
R10BIO_IsRecover will be progressed by handle_write_completed().
This function traverses all r10bio->devs[copies].
If devs[m].repl_bio != NULL, it thinks conf->mirrors[dev].replacement
is also not NULL. However, this is not always true.

When there is an rdev of raid10 has replacement, then each r10bio
->devs[m].repl_bio != NULL in conf->r10buf_pool. However, in 'recover',
even if corresponded replacement is NULL, it doesn't clear r10bio
->devs[m].repl_bio, resulting in replacement NULL deference.

This bug was introduced when replacement support for raid10 was
added in Linux 3.3.

As NeilBrown suggested:
	Elsewhere the determination of "is this device part of the
	resync/recovery" is made by resting bio->bi_end_io.
	If this is end_sync_write, then we tried to write here.
	If it is NULL, then we didn't try to write.

Fixes: 9ad1aefc8ae8 ("md/raid10:  Handle replacement devices during resync.")
Cc: stable (V3.3+)
Suggested-by: NeilBrown 
Signed-off-by: Yufen Yu 
Signed-off-by: Shaohua Li 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

md/raid10: reset the 'first' at the end of loop

2018-04-08T09:52:01+00:00

commit 6f287ca6046edd34ed83aafb7f9033c9c2e809e2 upstream.

We need to set "first = 0' at the end of rdev_for_each
loop, so we can get the array's min_offset_diff correctly
otherwise min_offset_diff just means the last rdev's
offset diff.

[only the first chunk, due to b506335e5d2b ("md/raid10: skip spare disk as
'first' disk") being already applied - gregkh]

Suggested-by: NeilBrown 
Signed-off-by: Guoqing Jiang 
Reviewed-by: NeilBrown 
Signed-off-by: Shaohua Li 
Cc: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

md/raid10: skip spare disk as 'first' disk

2018-03-24T09:58:45+00:00

[ Upstream commit b506335e5d2b4ec687dde392a3bdbf7601778f1d ]

Commit 6f287ca(md/raid10: reset the 'first' at the end of loop) ignores
a case in reshape, the first rdev could be a spare disk, which shouldn't
be accounted as the first disk since it doesn't include the offset info.

Fix: 6f287ca(md/raid10: reset the 'first' at the end of loop)
Cc: Guoqing Jiang 
Cc: NeilBrown 
Signed-off-by: Shaohua Li 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

md/raid10: wait up frozen array in handle_write_completed

2018-03-24T09:58:42+00:00

[ Upstream commit cf25ae78fc50010f66b9be945017796da34c434d ]

Since nr_queued is changed, we need to call wake_up here
if the array is already frozen and waiting for condition
"nr_pending == nr_queued + extra" to be true.

And commit 824e47daddbf ("RAID1: avoid unnecessary spin
locks in I/O barrier code") which has already added the
wake_up for raid1.

Signed-off-by: Guoqing Jiang 
Reviewed-by: NeilBrown 
Signed-off-by: Shaohua Li 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

md/raid10: submit bio directly to replacement disk

2017-10-08T08:14:20+00:00

[ Upstream commit 6d399783e9d4e9bd44931501948059d24ad96ff8 ]

Commit 57c67df(md/raid10: submit IO from originating thread instead of
md thread) submits bio directly for normal disks but not for replacement
disks. There is no point we shouldn't do this for replacement disks.

Cc: NeilBrown 
Signed-off-by: Shaohua Li 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

blk: Ensure users for current->bio_list can see the full list.

2017-04-08T07:53:32+00:00

commit f5fe1b51905df7cfe4fdfd85c5fb7bc5b71a094f upstream.

Commit 79bd99596b73 ("blk: improve order of bio handling in generic_make_request()")
changed current->bio_list so that it did not contain *all* of the
queued bios, but only those submitted by the currently running
make_request_fn.

There are two places which walk the list and requeue selected bios,
and others that check if the list is empty.  These are no longer
correct.

So redefine current->bio_list to point to an array of two lists, which
contain all queued bios, and adjust various code to test or walk both
lists.

Signed-off-by: NeilBrown 
Fixes: 79bd99596b73 ("blk: improve order of bio handling in generic_make_request()")
Signed-off-by: Jens Axboe 
[jwang: backport to 4.4]
Signed-off-by: Jack Wang 
Signed-off-by: Greg Kroah-Hartman 
[bwh: Restore changes in device-mapper from upstream version]
Signed-off-by: Ben Hutchings

raid10: increment write counter after bio is split

2017-03-30T07:35:18+00:00

commit 9b622e2bbcf049c82e2550d35fb54ac205965f50 upstream.

md pending write counter must be incremented after bio is split,
otherwise it gets decremented too many times in end bio callback and
becomes negative.

Signed-off-by: Tomasz Majchrzak 
Reviewed-by: Artur Paszkiewicz 
Signed-off-by: Shaohua Li 
Signed-off-by: Greg Kroah-Hartman

md/raid1/10: fix potential deadlock

2017-03-26T10:13:19+00:00

commit 61eb2b43b99ebdc9bc6bc83d9792257b243e7cb3 upstream.

Neil Brown pointed out a potential deadlock in raid 10 code with
bio_split/chain. The raid1 code could have the same issue, but recent
barrier rework makes it less likely to happen. The deadlock happens in
below sequence:

1. generic_make_request(bio), this will set current->bio_list
2. raid10_make_request will split bio to bio1 and bio2
3. __make_request(bio1), wait_barrer, add underlayer disk bio to
current->bio_list
4. __make_request(bio2), wait_barrer

If raise_barrier happens between 3 & 4, since wait_barrier runs at 3,
raise_barrier waits for IO completion from 3. And since raise_barrier
sets barrier, 4 waits for raise_barrier. But IO from 3 can't be
dispatched because raid10_make_request() doesn't finished yet.

The solution is to adjust the IO ordering. Quotes from Neil:
"
It is much safer to:

    if (need to split) {
        split = bio_split(bio, ...)
        bio_chain(...)
        make_request_fn(split);
        generic_make_request(bio);
   } else
        make_request_fn(mddev, bio);

This way we first process the initial section of the bio (in 'split')
which will queue some requests to the underlying devices.  These
requests will be queued in generic_make_request.
Then we queue the remainder of the bio, which will be added to the end
of the generic_make_request queue.
Then we return.
generic_make_request() will pop the lower-level device requests off the
queue and handle them first.  Then it will process the remainder
of the original bio once the first section has been fully processed.
"

Note, this only happens in read path. In write path, the bio is flushed to
underlaying disks either by blk flush (from schedule) or offladed to raid1/10d.
It's queued in current->bio_list.

Cc: Coly Li 
Suggested-by: NeilBrown 
Reviewed-by: Jack Wang 
Signed-off-by: Shaohua Li 
Signed-off-by: Greg Kroah-Hartman

raid10: include bio_end_io_list in nr_queued to prevent freeze_array hang

2016-04-12T16:08:57+00:00

commit 23ddba80ebe836476bb2fa1f5ef305dd1c63dc0b upstream.

This is the raid10 counterpart of the bug fixed by Nate
(raid1: include bio_end_io_list in nr_queued to prevent freeze_array hang)

Fixes: 95af587e95(md/raid10: ensure device failure recorded before write request returns)
Cc: Nate Dailey 
Signed-off-by: Shaohua Li 
Signed-off-by: Greg Kroah-Hartman