The commit is pushed to "branch-rh9-5.14.0-162.6.1.vz9.18.x-ovz" and will
appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh9-5.14.0-162.6.1.vz9.18.11
------>
commit 845cd8f772fc7e1ce34b7a910eff6a99d005cd24
Author: Andrey Zhadchenko <andrey.zhadche...@virtuozzo.com>
Date: Mon Feb 13 19:36:43 2023 +0300
dm/push_backup: Allow to stop push_backup at any time
Currently push_backup device cannot be stopped if any process
in a system is waiting next push block via push_backup_read.
This means we have to kill that process or thread to release
push_backup device, as it holds pb->ctl_rwsem.
Change code so push_backup is marked !alive and all waiters are
woken up before acquiring the lock. This is safe to do as pb->alive
is only used for determining if we should postpone new I/O and
process user push_backup_read/push_backup_write. All operations
like releasing I/O or memory will be done with acquired lock as
soon as all kicked readers exit syscall.
https://jira.sw.ru/browse/PSBM-145865
Signed-off-by: Andrey Zhadchenko <andrey.zhadche...@virtuozzo.com>
Feature: dm-backup: push backup target driver
---
drivers/md/dm-push-backup.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/md/dm-push-backup.c b/drivers/md/dm-push-backup.c
index b0e9e78f021a..370bd23a70ff 100644
--- a/drivers/md/dm-push-backup.c
+++ b/drivers/md/dm-push-backup.c
@@ -574,6 +574,17 @@ static int pb_message(struct dm_target *ti, unsigned int
argc, char **argv,
if (argc < 1)
goto out;
+ if (!strcmp(argv[0], "push_backup_stop")) {
+ if (argc != 1)
+ goto out;
+
+ if (!pb->map)
+ return -EBADF;
+
+ pb->alive = false;
+ wake_up_interruptible(&pb->waitq); /* pb->alive = false */
+ }
+
write = msg_wants_down_write(argv[0]);
if (write)
ret = down_write_killable(&pb->ctl_rwsem);
@@ -592,8 +603,6 @@ static int pb_message(struct dm_target *ti, unsigned int
argc, char **argv,
goto unlock;
ret = push_backup_start(pb, val, (void *)val2);
} else if (!strcmp(argv[0], "push_backup_stop")) {
- if (argc != 1)
- goto unlock;
ret = push_backup_stop(pb, result, maxlen);
} else if (!strcmp(argv[0], "push_backup_read")) {
if (argc != 1)
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