<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/md/raid5.c, branch linux-5.6.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>raid5: remove worker_cnt_per_group argument from alloc_thread_groups</title>
<updated>2020-01-13T19:44:09+00:00</updated>
<author>
<name>Guoqing Jiang</name>
<email>guoqing.jiang@cloud.ionos.com</email>
</author>
<published>2019-12-20T14:46:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d2c9ad41249ac862d3a3a4d5d56e6b1cd79d8a17'/>
<id>d2c9ad41249ac862d3a3a4d5d56e6b1cd79d8a17</id>
<content type='text'>
We can use "cnt" directly to update conf-&gt;worker_cnt_per_group
if alloc_thread_groups returns 0.

Signed-off-by: Guoqing Jiang &lt;guoqing.jiang@cloud.ionos.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
We can use "cnt" directly to update conf-&gt;worker_cnt_per_group
if alloc_thread_groups returns 0.

Signed-off-by: Guoqing Jiang &lt;guoqing.jiang@cloud.ionos.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>raid5: need to set STRIPE_HANDLE for batch head</title>
<updated>2019-12-11T18:12:09+00:00</updated>
<author>
<name>Guoqing Jiang</name>
<email>guoqing.jiang@cloud.ionos.com</email>
</author>
<published>2019-11-27T16:57:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a7ede3d16808b8f3915c8572d783530a82b2f027'/>
<id>a7ede3d16808b8f3915c8572d783530a82b2f027</id>
<content type='text'>
With commit 6ce220dd2f8ea71d6afc29b9a7524c12e39f374a ("raid5: don't set
STRIPE_HANDLE to stripe which is in batch list"), we don't want to set
STRIPE_HANDLE flag for sh which is already in batch list.

However, the stripe which is the head of batch list should set this flag,
otherwise panic could happen inside init_stripe at BUG_ON(sh-&gt;batch_head),
it is reproducible with raid5 on top of nvdimm devices per Xiao oberserved.

Thanks for Xiao's effort to verify the change.

Fixes: 6ce220dd2f8ea ("raid5: don't set STRIPE_HANDLE to stripe which is in batch list")
Reported-by: Xiao Ni &lt;xni@redhat.com&gt;
Tested-by: Xiao Ni &lt;xni@redhat.com&gt;
Signed-off-by: Guoqing Jiang &lt;guoqing.jiang@cloud.ionos.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
With commit 6ce220dd2f8ea71d6afc29b9a7524c12e39f374a ("raid5: don't set
STRIPE_HANDLE to stripe which is in batch list"), we don't want to set
STRIPE_HANDLE flag for sh which is already in batch list.

However, the stripe which is the head of batch list should set this flag,
otherwise panic could happen inside init_stripe at BUG_ON(sh-&gt;batch_head),
it is reproducible with raid5 on top of nvdimm devices per Xiao oberserved.

Thanks for Xiao's effort to verify the change.

Fixes: 6ce220dd2f8ea ("raid5: don't set STRIPE_HANDLE to stripe which is in batch list")
Reported-by: Xiao Ni &lt;xni@redhat.com&gt;
Tested-by: Xiao Ni &lt;xni@redhat.com&gt;
Signed-off-by: Guoqing Jiang &lt;guoqing.jiang@cloud.ionos.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drivers/md/raid5.c: use the new spelling of RWH_WRITE_LIFE_NOT_SET</title>
<updated>2019-11-14T22:59:15+00:00</updated>
<author>
<name>Eugene Syromiatnikov</name>
<email>esyr@redhat.com</email>
</author>
<published>2019-09-20T15:58:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f1934892bd76ec127af4dd1ed17b73bc29b944a8'/>
<id>f1934892bd76ec127af4dd1ed17b73bc29b944a8</id>
<content type='text'>
As it is consistent with prefixes of other write life time hints.

Signed-off-by: Eugene Syromiatnikov &lt;esyr@redhat.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
As it is consistent with prefixes of other write life time hints.

Signed-off-by: Eugene Syromiatnikov &lt;esyr@redhat.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>md: improve handling of bio with REQ_PREFLUSH in md_flush_request()</title>
<updated>2019-10-24T22:22:40+00:00</updated>
<author>
<name>David Jeffery</name>
<email>djeffery@redhat.com</email>
</author>
<published>2019-09-16T17:15:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=775d78319f1ceb32be8eb3b1202ccdc60e9cb7f1'/>
<id>775d78319f1ceb32be8eb3b1202ccdc60e9cb7f1</id>
<content type='text'>
If pers-&gt;make_request fails in md_flush_request(), the bio is lost. To
fix this, pass back a bool to indicate if the original make_request call
should continue to handle the I/O and instead of assuming the flush logic
will push it to completion.

Convert md_flush_request to return a bool and no longer calls the raid
driver's make_request function.  If the return is true, then the md flush
logic has or will complete the bio and the md make_request call is done.
If false, then the md make_request function needs to keep processing like
it is a normal bio. Let the original call to md_handle_request handle any
need to retry sending the bio to the raid driver's make_request function
should it be needed.

Also mark md_flush_request and the make_request function pointer as
__must_check to issue warnings should these critical return values be
ignored.

Fixes: 2bc13b83e629 ("md: batch flush requests.")
Cc: stable@vger.kernel.org # # v4.19+
Cc: NeilBrown &lt;neilb@suse.com&gt;
Signed-off-by: David Jeffery &lt;djeffery@redhat.com&gt;
Reviewed-by: Xiao Ni &lt;xni@redhat.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
If pers-&gt;make_request fails in md_flush_request(), the bio is lost. To
fix this, pass back a bool to indicate if the original make_request call
should continue to handle the I/O and instead of assuming the flush logic
will push it to completion.

Convert md_flush_request to return a bool and no longer calls the raid
driver's make_request function.  If the return is true, then the md flush
logic has or will complete the bio and the md make_request call is done.
If false, then the md make_request function needs to keep processing like
it is a normal bio. Let the original call to md_handle_request handle any
need to retry sending the bio to the raid driver's make_request function
should it be needed.

Also mark md_flush_request and the make_request function pointer as
__must_check to issue warnings should these critical return values be
ignored.

Fixes: 2bc13b83e629 ("md: batch flush requests.")
Cc: stable@vger.kernel.org # # v4.19+
Cc: NeilBrown &lt;neilb@suse.com&gt;
Signed-off-by: David Jeffery &lt;djeffery@redhat.com&gt;
Reviewed-by: Xiao Ni &lt;xni@redhat.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>raid5: remove STRIPE_OPS_REQ_PENDING</title>
<updated>2019-09-13T20:14:39+00:00</updated>
<author>
<name>Guoqing Jiang</name>
<email>guoqing.jiang@cloud.ionos.com</email>
</author>
<published>2019-09-12T10:10:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=feb9bf9849e2aa0dd2833285af7c25aee07df7bb'/>
<id>feb9bf9849e2aa0dd2833285af7c25aee07df7bb</id>
<content type='text'>
This stripe state is not used anymore after commit 51acbcec6c42b24
("md: remove CONFIG_MULTICORE_RAID456"), so remove the obsoleted
state.

gjiang@nb01257:~/md$ grep STRIPE_OPS_REQ_PENDING drivers/md/ -r
drivers/md/raid5.c:					  (1 &lt;&lt; STRIPE_OPS_REQ_PENDING) |
drivers/md/raid5.h:	STRIPE_OPS_REQ_PENDING,

Signed-off-by: Guoqing Jiang &lt;guoqing.jiang@cloud.ionos.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This stripe state is not used anymore after commit 51acbcec6c42b24
("md: remove CONFIG_MULTICORE_RAID456"), so remove the obsoleted
state.

gjiang@nb01257:~/md$ grep STRIPE_OPS_REQ_PENDING drivers/md/ -r
drivers/md/raid5.c:					  (1 &lt;&lt; STRIPE_OPS_REQ_PENDING) |
drivers/md/raid5.h:	STRIPE_OPS_REQ_PENDING,

Signed-off-by: Guoqing Jiang &lt;guoqing.jiang@cloud.ionos.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>raid5: don't set STRIPE_HANDLE to stripe which is in batch list</title>
<updated>2019-09-13T20:10:05+00:00</updated>
<author>
<name>Guoqing Jiang</name>
<email>guoqing.jiang@cloud.ionos.com</email>
</author>
<published>2019-09-11T08:06:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6ce220dd2f8ea71d6afc29b9a7524c12e39f374a'/>
<id>6ce220dd2f8ea71d6afc29b9a7524c12e39f374a</id>
<content type='text'>
If stripe in batch list is set with STRIPE_HANDLE flag, then the stripe
could be set with STRIPE_ACTIVE by the handle_stripe function. And if
error happens to the batch_head at the same time, break_stripe_batch_list
is called, then below warning could happen (the same report in [1]), it
means a member of batch list was set with STRIPE_ACTIVE.

[7028915.431770] stripe state: 2001
[7028915.431815] ------------[ cut here ]------------
[7028915.431828] WARNING: CPU: 18 PID: 29089 at drivers/md/raid5.c:4614 break_stripe_batch_list+0x203/0x240 [raid456]
[...]
[7028915.431879] CPU: 18 PID: 29089 Comm: kworker/u82:5 Tainted: G           O    4.14.86-1-storage #4.14.86-1.2~deb9
[7028915.431881] Hardware name: Supermicro SSG-2028R-ACR24L/X10DRH-iT, BIOS 3.1 06/18/2018
[7028915.431888] Workqueue: raid5wq raid5_do_work [raid456]
[7028915.431890] task: ffff9ab0ef36d7c0 task.stack: ffffb72926f84000
[7028915.431896] RIP: 0010:break_stripe_batch_list+0x203/0x240 [raid456]
[7028915.431898] RSP: 0018:ffffb72926f87ba8 EFLAGS: 00010286
[7028915.431900] RAX: 0000000000000012 RBX: ffff9aaa84a98000 RCX: 0000000000000000
[7028915.431901] RDX: 0000000000000000 RSI: ffff9ab2bfa15458 RDI: ffff9ab2bfa15458
[7028915.431902] RBP: ffff9aaa8fb4e900 R08: 0000000000000001 R09: 0000000000002eb4
[7028915.431903] R10: 00000000ffffffff R11: 0000000000000000 R12: ffff9ab1736f1b00
[7028915.431904] R13: 0000000000000000 R14: ffff9aaa8fb4e900 R15: 0000000000000001
[7028915.431906] FS:  0000000000000000(0000) GS:ffff9ab2bfa00000(0000) knlGS:0000000000000000
[7028915.431907] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[7028915.431908] CR2: 00007ff953b9f5d8 CR3: 0000000bf4009002 CR4: 00000000003606e0
[7028915.431909] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[7028915.431910] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[7028915.431910] Call Trace:
[7028915.431923]  handle_stripe+0x8e7/0x2020 [raid456]
[7028915.431930]  ? __wake_up_common_lock+0x89/0xc0
[7028915.431935]  handle_active_stripes.isra.58+0x35f/0x560 [raid456]
[7028915.431939]  raid5_do_work+0xc6/0x1f0 [raid456]

Also commit 59fc630b8b5f9f ("RAID5: batch adjacent full stripe write")
said "If a stripe is added to batch list, then only the first stripe
of the list should be put to handle_list and run handle_stripe."

So don't set STRIPE_HANDLE to stripe which is already in batch list,
otherwise the stripe could be put to handle_list and run handle_stripe,
then the above warning could be triggered.

[1]. https://www.spinics.net/lists/raid/msg62552.html

Signed-off-by: Guoqing Jiang &lt;guoqing.jiang@cloud.ionos.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
If stripe in batch list is set with STRIPE_HANDLE flag, then the stripe
could be set with STRIPE_ACTIVE by the handle_stripe function. And if
error happens to the batch_head at the same time, break_stripe_batch_list
is called, then below warning could happen (the same report in [1]), it
means a member of batch list was set with STRIPE_ACTIVE.

[7028915.431770] stripe state: 2001
[7028915.431815] ------------[ cut here ]------------
[7028915.431828] WARNING: CPU: 18 PID: 29089 at drivers/md/raid5.c:4614 break_stripe_batch_list+0x203/0x240 [raid456]
[...]
[7028915.431879] CPU: 18 PID: 29089 Comm: kworker/u82:5 Tainted: G           O    4.14.86-1-storage #4.14.86-1.2~deb9
[7028915.431881] Hardware name: Supermicro SSG-2028R-ACR24L/X10DRH-iT, BIOS 3.1 06/18/2018
[7028915.431888] Workqueue: raid5wq raid5_do_work [raid456]
[7028915.431890] task: ffff9ab0ef36d7c0 task.stack: ffffb72926f84000
[7028915.431896] RIP: 0010:break_stripe_batch_list+0x203/0x240 [raid456]
[7028915.431898] RSP: 0018:ffffb72926f87ba8 EFLAGS: 00010286
[7028915.431900] RAX: 0000000000000012 RBX: ffff9aaa84a98000 RCX: 0000000000000000
[7028915.431901] RDX: 0000000000000000 RSI: ffff9ab2bfa15458 RDI: ffff9ab2bfa15458
[7028915.431902] RBP: ffff9aaa8fb4e900 R08: 0000000000000001 R09: 0000000000002eb4
[7028915.431903] R10: 00000000ffffffff R11: 0000000000000000 R12: ffff9ab1736f1b00
[7028915.431904] R13: 0000000000000000 R14: ffff9aaa8fb4e900 R15: 0000000000000001
[7028915.431906] FS:  0000000000000000(0000) GS:ffff9ab2bfa00000(0000) knlGS:0000000000000000
[7028915.431907] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[7028915.431908] CR2: 00007ff953b9f5d8 CR3: 0000000bf4009002 CR4: 00000000003606e0
[7028915.431909] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[7028915.431910] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[7028915.431910] Call Trace:
[7028915.431923]  handle_stripe+0x8e7/0x2020 [raid456]
[7028915.431930]  ? __wake_up_common_lock+0x89/0xc0
[7028915.431935]  handle_active_stripes.isra.58+0x35f/0x560 [raid456]
[7028915.431939]  raid5_do_work+0xc6/0x1f0 [raid456]

Also commit 59fc630b8b5f9f ("RAID5: batch adjacent full stripe write")
said "If a stripe is added to batch list, then only the first stripe
of the list should be put to handle_list and run handle_stripe."

So don't set STRIPE_HANDLE to stripe which is already in batch list,
otherwise the stripe could be put to handle_list and run handle_stripe,
then the above warning could be triggered.

[1]. https://www.spinics.net/lists/raid/msg62552.html

Signed-off-by: Guoqing Jiang &lt;guoqing.jiang@cloud.ionos.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>raid5: don't increment read_errors on EILSEQ return</title>
<updated>2019-09-13T20:10:05+00:00</updated>
<author>
<name>Nigel Croxon</name>
<email>ncroxon@redhat.com</email>
</author>
<published>2019-09-06T13:21:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b76b4715eba0d0ed574f58918b29c1b2f0fa37a8'/>
<id>b76b4715eba0d0ed574f58918b29c1b2f0fa37a8</id>
<content type='text'>
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-&gt;read_errors beyond
conf-&gt;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 &lt;ncroxon@redhat.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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-&gt;read_errors beyond
conf-&gt;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 &lt;ncroxon@redhat.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>md/raid5: use bio_end_sector to calculate last_sector</title>
<updated>2019-09-03T21:52:38+00:00</updated>
<author>
<name>Guoqing Jiang</name>
<email>jgq516@gmail.com</email>
</author>
<published>2019-09-03T09:41:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b0f01ecf293c49d841abbf8b55c4b717936ab11e'/>
<id>b0f01ecf293c49d841abbf8b55c4b717936ab11e</id>
<content type='text'>
Use the common way to get last_sector.

Signed-off-by: Guoqing Jiang &lt;guoqing.jiang@cloud.ionos.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Use the common way to get last_sector.

Signed-off-by: Guoqing Jiang &lt;guoqing.jiang@cloud.ionos.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>raid5 improve too many read errors msg by adding limits</title>
<updated>2019-08-27T19:36:37+00:00</updated>
<author>
<name>Nigel Croxon</name>
<email>ncroxon@redhat.com</email>
</author>
<published>2019-08-21T13:27:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0009fad033370802de75e4cedab54f4d86450e22'/>
<id>0009fad033370802de75e4cedab54f4d86450e22</id>
<content type='text'>
Often limits can be changed by admin. When discussing such things
it helps if you can provide "self-sustained" facts. Also
sometimes the admin thinks he changed a limit, but it did not
take effect for some reason or he changed the wrong thing.

V3: Only pr_warn when Faulty is 0.
V2: Add read_errors value to pr_warn.

Signed-off-by: Nigel Croxon &lt;ncroxon@redhat.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Often limits can be changed by admin. When discussing such things
it helps if you can provide "self-sustained" facts. Also
sometimes the admin thinks he changed a limit, but it did not
take effect for some reason or he changed the wrong thing.

V3: Only pr_warn when Faulty is 0.
V2: Add read_errors value to pr_warn.

Signed-off-by: Nigel Croxon &lt;ncroxon@redhat.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>md/raid6: Set R5_ReadError when there is read failure on parity disk</title>
<updated>2019-08-07T17:25:02+00:00</updated>
<author>
<name>Xiao Ni</name>
<email>xni@redhat.com</email>
</author>
<published>2019-07-08T02:14:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=143f6e733b73051cd22dcb80951c6c929da413ce'/>
<id>143f6e733b73051cd22dcb80951c6c929da413ce</id>
<content type='text'>
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-&gt;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 &lt;lkp@intel.com&gt;

Fixes: 7471fb77ce4d ("md/raid6: Fix anomily when recovering a single device in RAID6.")
Cc: &lt;stable@vger.kernel.org&gt; #4.4+
Signed-off-by: Xiao Ni &lt;xni@redhat.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
</content>
<content type='xhtml'>
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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-&gt;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 &lt;lkp@intel.com&gt;

Fixes: 7471fb77ce4d ("md/raid6: Fix anomily when recovering a single device in RAID6.")
Cc: &lt;stable@vger.kernel.org&gt; #4.4+
Signed-off-by: Xiao Ni &lt;xni@redhat.com&gt;
Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
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