On Thu, Nov 19, 2020 at 12:45:53AM +0800, Zhao Heming wrote:
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/md0Signed-off-by: Zhao Heming heming.zhao@suse.com
drivers/md/md.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
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This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html for how to do this properly.
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