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  1. 30 Nov, 2020 6 commits
    • Zhao Heming's avatar
      md/cluster: block reshape with remote resync job · a8da01f7
      Zhao Heming authored 
      Reshape request should be blocked with ongoing resync job. In cluster
env, a node can start resync job even if the resync cmd isn't executed
on it, e.g., user executes "mdadm --grow" on node A, sometimes node B
will start resync job. However, current update_raid_disks() only check
local recovery status, which is incomplete. As a result, we see user will
execute "mdadm --grow" successfully on local, while the remote node deny
to do reshape job when it doing resync job. The inconsistent handling
cause array enter unexpected status. If user doesn't observe this issue
and continue executing mdadm cmd, the array doesn't work at last.

Fix this issue by blocking reshape request. When node executes "--grow"
and detects ongoing resync, it should stop and report error to user.

The following script reproduces the issue with ~100% probability.
(two nodes share 3 iSCSI luns: sdg/sdh/sdi. Each lun size is 1GB)
```
 # on node1, node2 is the remote node.
ssh root@node2 "mdadm -S --scan"
mdadm -S --scan
for i in {g,h,i};do dd if=/dev/zero of=/dev/sd$i oflag=direct bs=1M \
count=20; done

mdadm -C /dev/md0 -b clustered -e 1.2 -n 2 -l mirror /dev/sdg /dev/sdh
ssh root@node2 "mdadm -A /dev/md0 /dev/sdg /dev/sdh"

sleep 5

mdadm --manage --add /dev/md0 /dev/sdi
mdadm --wait /dev/md0
mdadm --grow --raid-devices=3 /dev/md0

mdadm /dev/md0 --fail /dev/sdg
mdadm /dev/md0 --remove /dev/sdg
mdadm --grow --raid-devices=2 /dev/md0
```

Cc: stable@vger.kernel.org
Signed-off-by: default avatarZhao Heming <heming.zhao@suse.com>
Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
      a8da01f7
    • Pankaj Gupta's avatar
      md: use current request time as base for ktime comparisons · a23f2aae
      Pankaj Gupta authored 
      Request coalescing logic uses 'prev_flush_start' as base to
compare the current request start time. 'prev_flush_start' is
updated in other context.

This patch changes this by using ktime comparison base to
'req_start' for better readability of code.
Signed-off-by: default avatarPankaj Gupta <pankaj.gupta@cloud.ionos.com>
Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
      a23f2aae
    • Pankaj Gupta's avatar
      md: add comments in md_flush_request() · 204d1a64
      Pankaj Gupta authored 
      Request coalescing logic is dependent on flush time update in other
context. This patch adds comments to understand the code flow better.
Signed-off-by: default avatarPankaj Gupta <pankaj.gupta@cloud.ionos.com>
Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
      204d1a64
    • Pankaj Gupta's avatar
      md: improve variable names in md_flush_request() · 81ba3c24
      Pankaj Gupta authored 
      This patch improves readability by using better variable names
in flush request coalescing logic.
Signed-off-by: default avatarPankaj Gupta <pankaj.gupta@cloud.ionos.com>
Reviewed-by: default avatarPaul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
      81ba3c24
    • Kevin Vigor's avatar
      md/raid10: initialize r10_bio->read_slot before use. · 93decc56
      Kevin Vigor authored 
      In __make_request() a new r10bio is allocated and passed to
raid10_read_request(). The read_slot member of the bio is not
initialized, and the raid10_read_request() uses it to index an
array. This leads to occasional panics.

Fix by initializing the field to invalid value and checking for
valid value in raid10_read_request().

Cc: stable@vger.kernel.org
Signed-off-by: default avatarKevin Vigor <kvigor@gmail.com>
Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
      93decc56
    • Dae R. Jeong's avatar
      md: fix a warning caused by a race between concurrent md_ioctl()s · c731b84b
      Dae R. Jeong authored 
      Syzkaller reports a warning as belows.
WARNING: CPU: 0 PID: 9647 at drivers/md/md.c:7169
...
Call Trace:
...
RIP: 0010:md_ioctl+0x4017/0x5980 drivers/md/md.c:7169
RSP: 0018:ffff888096027950 EFLAGS: 00010293
RAX: ffff88809322c380 RBX: 0000000000000932 RCX: ffffffff84e266f2
RDX: 0000000000000000 RSI: ffffffff84e299f7 RDI: 0000000000000007
RBP: ffff888096027bc0 R08: ffff88809322c380 R09: ffffed101341a482
R10: ffff888096027940 R11: ffff88809a0d240f R12: 0000000000000932
R13: ffff8880a2c14100 R14: ffff88809a0d2268 R15: ffff88809a0d2408
 __blkdev_driver_ioctl block/ioctl.c:304 [inline]
 blkdev_ioctl+0xece/0x1c10 block/ioctl.c:606
 block_ioctl+0xee/0x130 fs/block_dev.c:1930
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0xd5f/0x1380 fs/ioctl.c:696
 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

This is caused by a race between two concurrenct md_ioctl()s closing
the array.
CPU1 (md_ioctl())                   CPU2 (md_ioctl())
------                              ------
set_bit(MD_CLOSING, &mddev->flags);
did_set_md_closing = true;
                                    WARN_ON_ONCE(test_bit(MD_CLOSING,
                                            &mddev->flags));
if(did_set_md_closing)
    clear_bit(MD_CLOSING, &mddev->flags);

Fix the warning by returning immediately if the MD_CLOSING bit is set
in &mddev->flags which indicates that the array is being closed.

Fixes: 065e519e ("md: MD_CLOSING needs to be cleared after called md_set_readonly or do_md_stop")
Reported-by: syzbot+1e46a0864c1a6e9bd3d8@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: default avatarDae R. Jeong <dae.r.jeong@kaist.ac.kr>
Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
      c731b84b
  3. 16 Nov, 2020 34 commits
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