[PATCH 2/3] md: Set MD_BROKEN for RAID1 and RAID10
From: Mariusz Tkaczyk <hidden>
Date: 2021-12-16 14:53:16
Subsystem:
software raid (multiple disks) support, the rest · Maintainers:
Song Liu, Yu Kuai, Linus Torvalds
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
removed from RAID1/RAID10.") is disabled.
Signed-off-by: Mariusz Tkaczyk <redacted>
---
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 + * 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))
--
2.26.2