On 12/16/21 10:52 PM, Mariusz Tkaczyk wrote:
There was no direct mechanism to determine raid failure outside
personality. It was done by checking rdev->flags after executing
md_error(). If "faulty" was not set then -EBUSY was returned to
userspace. It causes that mdadm expects -EBUSY if the array
becomes failed. There are some reasons to not consider this mechanism
as correct:
- drive can't be failed for different reasons.
- there are path where -EBUSY is not reported and drive removal leads
to failed array, without notification for userspace.
- in the array failure case -EBUSY seems to be wrong status. Array is
not busy, but removal process cannot proceed safe.
-EBUSY expectation cannot be removed without breaking compatibility
with userspace, but we can adopt the failed state verification method.
In this patch MD_BROKEN flag support, used to mark non-redundant array
as dead, is added to RAID1 and RAID10. Support for RAID456 is added in
next commit.
Now the array failure can be checked, so verify MD_BROKEN flag, however
still return -EBUSY to userspace.
As in previous commit, it causes that #mdadm --set-faulty is able to
mark array as failed. Previously proposed workaround is valid if optional
functionality 9a567843f79("md: allow last device to be forcibly
s/9a567843f79/9a567843f7ce/
removed from RAID1/RAID10.") is disabled.
Signed-off-by: Mariusz Tkaczyk <mariusz.tkaczyk@xxxxxxxxxxxxxxx>
---
drivers/md/md.c | 17 ++++++++++-------
drivers/md/md.h | 4 ++--
drivers/md/raid1.c | 1 +
drivers/md/raid10.c | 1 +
4 files changed, 14 insertions(+), 9 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index f888ef197765..fda8473f96b8 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2983,10 +2983,11 @@ state_store(struct md_rdev *rdev, const char *buf, size_t len)
if (cmd_match(buf, "faulty") && rdev->mddev->pers) {
md_error(rdev->mddev, rdev);
- if (test_bit(Faulty, &rdev->flags))
- err = 0;
- else
+
+ if (test_bit(MD_BROKEN, &rdev->mddev->flags))
err = -EBUSY;
+ else
+ err = 0;
} else if (cmd_match(buf, "remove")) {
if (rdev->mddev->pers) {
clear_bit(Blocked, &rdev->flags);
@@ -7441,7 +7442,7 @@ static int set_disk_faulty(struct mddev *mddev, dev_t dev)
err = -ENODEV;
else {
md_error(mddev, rdev);
- if (!test_bit(Faulty, &rdev->flags))
+ if (test_bit(MD_BROKEN, &mddev->flags))
err = -EBUSY;
}
rcu_read_unlock();
@@ -7987,12 +7988,14 @@ void md_error(struct mddev *mddev, struct md_rdev *rdev)
if (!mddev->pers->sync_request)
return;
- if (mddev->degraded)
+ if (mddev->degraded && !test_bit(MD_BROKEN, &mddev->flags))
set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
sysfs_notify_dirent_safe(rdev->sysfs_state);
set_bit(MD_RECOVERY_INTR, &mddev->recovery);
- set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
- md_wakeup_thread(mddev->thread);
+ if (!test_bit(MD_BROKEN, &mddev->flags)) {
+ set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+ md_wakeup_thread(mddev->thread);
+ }
if (mddev->event_work.func)
queue_work(md_misc_wq, &mddev->event_work);
md_new_event();
diff --git a/drivers/md/md.h b/drivers/md/md.h
index bc3f2094d0b6..d3a897868695 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -259,8 +259,8 @@ enum mddev_flags {
MD_NOT_READY, /* do_md_run() is active, so 'array_state'
* must not report that array is ready yet
*/
- MD_BROKEN, /* This is used in RAID-0/LINEAR only, to stop
- * I/O in case an array member is gone/failed.
+ MD_BROKEN, /* This is used to stop I/O and mark device as
IIUC, 'device' actually means array, if so, could you change it to array
to make it clear?
+ * dead in case an array becomes failed.
*/
};
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 7dc8026cf6ee..45dc75f90476 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1638,6 +1638,7 @@ static void raid1_error(struct mddev *mddev, struct md_rdev *rdev)
*/
conf->recovery_disabled = mddev->recovery_disabled;
spin_unlock_irqrestore(&conf->device_lock, flags);
+ set_bit(MD_BROKEN, &mddev->flags);
return;
}
set_bit(Blocked, &rdev->flags);
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index dde98f65bd04..d7cefd212e6b 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1964,6 +1964,7 @@ static void raid10_error(struct mddev *mddev, struct md_rdev *rdev)
* Don't fail the drive, just return an IO error.
*/
spin_unlock_irqrestore(&conf->device_lock, flags);
+ set_bit(MD_BROKEN, &mddev->flags);
return;
}
if (test_and_clear_bit(In_sync, &rdev->flags))
Thanks,
Guoqing
