When initiating a stripe adding reshape, a deadlock between
md_stop_writes() waiting for the sync thread to stop and the
running sync thread waiting for inactive stripes occurs
(this frequently happens on single-core but rarely
on multi-core systems).
Resolve by setting MD_RECOVERY_WAIT to request the main MD
resynchronization thread worker function md_do_sync() to bail
out when initiating the reshape via constructor arguments.
Don't set the flag when reloading without those arguments and
avoid superfluous mddev_{suspend,resume} setting up reshape.
Passes all lvm2 raid tests.
Signed-off-by: Heinz Mauelshagen <heinzm@xxxxxxxxxx>
---
Documentation/device-mapper/dm-raid.txt | 1 +
drivers/md/dm-raid.c | 13 ++++---------
2 files changed, 5 insertions(+), 9 deletions(-)
diff --git a/Documentation/device-mapper/dm-raid.txt b/Documentation/device-mapper/dm-raid.txt
index f68d06d6f28b..efb73f521568 100644
--- a/Documentation/device-mapper/dm-raid.txt
+++ b/Documentation/device-mapper/dm-raid.txt
@@ -349,3 +349,4 @@ Version History
state races.
1.13.2 Fix raid redundancy validation and avoid keeping raid set frozen
1.13.3 Fix reshape race on small devices
+1.14.0 Fix stripe adding reshape deadlock/potential data corruption
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index ecb7706f7330..03dd915eff9e 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -3871,14 +3871,13 @@ static int rs_start_reshape(struct raid_set *rs)
struct mddev *mddev = &rs->md;
struct md_personality *pers = mddev->pers;
+ /* Don't allow the sync thread to work until the table gets reloaded. */
+ set_bit(MD_RECOVERY_WAIT, &mddev->recovery);
+
r = rs_setup_reshape(rs);
if (r)
return r;
- /* Need to be resumed to be able to start reshape, recovery is frozen until raid_resume() though */
- if (test_and_clear_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags))
- mddev_resume(mddev);
-
/*
* Check any reshape constraints enforced by the personalility
*
@@ -3902,10 +3901,6 @@ static int rs_start_reshape(struct raid_set *rs)
}
}
- /* Suspend because a resume will happen in raid_resume() */
- set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags);
- mddev_suspend(mddev);
-
/*
* Now reshape got set up, update superblocks to
* reflect the fact so that a table reload will
@@ -4002,7 +3997,7 @@ static void raid_resume(struct dm_target *ti)
static struct target_type raid_target = {
.name = "raid",
- .version = {1, 13, 3},
+ .version = {1, 14, 0},
.module = THIS_MODULE,
.ctr = raid_ctr,
.dtr = raid_dtr,
--
2.17.1
--
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