[PATCH v4 3/4] md: sync blockdev before stopping raid or setting readonly

From: linan666
Date: Fri Jan 26 2024 - 05:09:05 EST


From: Li Nan <linan122@xxxxxxxxxx>

Commit a05b7ea03d72 ("md: avoid crash when stopping md array races
with closing other open fds.") added sync_block before stopping raid and
setting readonly. Later in commit 260fa034ef7a ("md: avoid deadlock when
dirty buffers during md_stop.") it is moved to ioctl. array_state_store()
was ignored. Add sync blockdev to array_state_store() now.

Signed-off-by: Li Nan <linan122@xxxxxxxxxx>
---
drivers/md/md.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 40ab5c7ce394..24e33b65c6ff 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4478,6 +4478,7 @@ array_state_store(struct mddev *mddev, const char *buf, size_t len)
{
int err = 0;
enum array_state st = match_word(buf, array_states);
+ bool clear_md_closing = false;

/* No lock dependent actions */
switch (st) {
@@ -4487,6 +4488,17 @@ array_state_store(struct mddev *mddev, const char *buf, size_t len)
case broken: /* cannot be set */
case bad_word:
return -EINVAL;
+ case clear:
+ case readonly:
+ case inactive:
+ case read_auto:
+ if (!mddev->pers || !md_is_rdwr(mddev))
+ break;
+ err = mddev_set_closing_and_sync_blockdev(mddev);
+ if (err)
+ return err;
+ clear_md_closing = true;
+ break;
default:
break;
}
@@ -4512,6 +4524,7 @@ array_state_store(struct mddev *mddev, const char *buf, size_t len)
spin_unlock(&mddev->lock);
return err ?: len;
}
+
err = mddev_lock(mddev);
if (err)
return err;
@@ -4524,6 +4537,8 @@ array_state_store(struct mddev *mddev, const char *buf, size_t len)
break;
case clear:
err = do_md_stop(mddev, 0, NULL);
+ if (!err)
+ clear_md_closing = false;
break;
case readonly:
if (mddev->pers)
@@ -4586,6 +4601,10 @@ array_state_store(struct mddev *mddev, const char *buf, size_t len)
sysfs_notify_dirent_safe(mddev->sysfs_state);
}
mddev_unlock(mddev);
+
+ if (clear_md_closing)
+ clear_bit(MD_CLOSING, &mddev->flags);
+
return err ?: len;
}
static struct md_sysfs_entry md_array_state =
--
2.39.2