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| author | David Jeffery <djeffery@redhat.com> | 2023-11-28 19:11:39 +0100 |
|---|---|---|
| committer | Song Liu <song@kernel.org> | 2023-12-01 23:43:29 +0100 |
| commit | c467e97f079f0019870c314996fae952cc768e82 (patch) | |
| tree | 331327bd07a21b7a503a608797e43889d03bc627 /drivers/md | |
| parent | md: fix bi_status reporting in md_end_clone_io (diff) | |
| download | linux-c467e97f079f0019870c314996fae952cc768e82.tar.xz linux-c467e97f079f0019870c314996fae952cc768e82.zip | |
md/raid6: use valid sector values to determine if an I/O should wait on the reshape
During a reshape or a RAID6 array such as expanding by adding an additional
disk, I/Os to the region of the array which have not yet been reshaped can
stall indefinitely. This is from errors in the stripe_ahead_of_reshape
function causing md to think the I/O is to a region in the actively
undergoing the reshape.
stripe_ahead_of_reshape fails to account for the q disk having a sector
value of 0. By not excluding the q disk from the for loop, raid6 will always
generate a min_sector value of 0, causing a return value which stalls.
The function's max_sector calculation also uses min() when it should use
max(), causing the max_sector value to always be 0. During a backwards
rebuild this can cause the opposite problem where it allows I/O to advance
when it should wait.
Fixing these errors will allow safe I/O to advance in a timely manner and
delay only I/O which is unsafe due to stripes in the middle of undergoing
the reshape.
Fixes: 486f60558607 ("md/raid5: Check all disks in a stripe_head for reshape progress")
Cc: stable@vger.kernel.org # v6.0+
Signed-off-by: David Jeffery <djeffery@redhat.com>
Tested-by: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20231128181233.6187-1-djeffery@redhat.com
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/raid5.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index dc031d42f53b..26e1e8a5e941 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -5892,11 +5892,11 @@ static bool stripe_ahead_of_reshape(struct mddev *mddev, struct r5conf *conf, int dd_idx; for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) { - if (dd_idx == sh->pd_idx) + if (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx) continue; min_sector = min(min_sector, sh->dev[dd_idx].sector); - max_sector = min(max_sector, sh->dev[dd_idx].sector); + max_sector = max(max_sector, sh->dev[dd_idx].sector); } spin_lock_irq(&conf->device_lock); |