From 9631abdbf406c764f2a5d8305eac063bc3396a0a Mon Sep 17 00:00:00 2001
From: Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>
Date: Tue, 22 Mar 2022 16:23:38 +0100
Subject: [PATCH] md: Set MD_BROKEN for RAID1 and RAID10
Git-commit: 9631abdbf406c764f2a5d8305eac063bc3396a0a
Patch-mainline: v5.19-rc1
References: jsc#PED-2766
There is no direct mechanism to determine raid failure outside
personality. It is done by checking rdev->flags after executing
md_error(). If "faulty" flag is not set then -EBUSY is returned to
userspace. -EBUSY means that array will be failed after drive removal.
Mdadm has special routine to handle the array failure and it is executed
if -EBUSY is returned by md.
There are at least two known reasons to not consider this mechanism
as correct:
1. drive can be removed even if array will be failed[1].
2. -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. In this patch first issue is resolved by adding support
for MD_BROKEN flag for RAID1 and RAID10. Support for RAID456 is added in
next commit.
The idea is to set the MD_BROKEN if we are sure that raid is in failed
state now. This is done in each error_handler(). In md_error() MD_BROKEN
flag is checked. If is set, then -EBUSY is returned to userspace.
As in previous commit, it causes that #mdadm --set-faulty is able to
fail array. Previously proposed workaround is valid if optional
functionality[1] is disabled.
[1] commit 9a567843f7ce("md: allow last device to be forcibly removed from
RAID1/RAID10.")
Reviewd-by: Xiao Ni <xni@redhat.com>
Signed-off-by: Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Coly Li <colyli@suse.de>
---
drivers/md/md.c | 27 +++++++++++---------
drivers/md/md.h | 62 +++++++++++++++++++++++++--------------------
drivers/md/raid1.c | 43 ++++++++++++++++++-------------
drivers/md/raid10.c | 40 +++++++++++++++++------------
4 files changed, 100 insertions(+), 72 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 2587f872c088..9294f13e0c9d 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2984,10 +2984,11 @@ 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);
@@ -4353,10 +4354,9 @@ __ATTR_PREALLOC(resync_start, S_IRUGO|S_IWUSR,
* like active, but no writes have been seen for a while (100msec).
*
* broken
- * RAID0/LINEAR-only: same as clean, but array is missing a member.
- * It's useful because RAID0/LINEAR mounted-arrays aren't stopped
- * when a member is gone, so this state will at least alert the
- * user that something is wrong.
+* Array is failed. It's useful because mounted-arrays aren't stopped
+* when array is failed, so this state will at least alert the user that
+* something is wrong.
*/
enum array_state { clear, inactive, suspended, readonly, read_auto, clean, active,
write_pending, active_idle, broken, bad_word};
@@ -7443,7 +7443,7 @@ 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();
@@ -7984,13 +7984,16 @@ void md_error(struct mddev *mddev, struct md_rdev *rdev)
if (!mddev->pers || !mddev->pers->error_handler)
return;
- mddev->pers->error_handler(mddev,rdev);
- if (mddev->degraded)
+ mddev->pers->error_handler(mddev, rdev);
+
+ 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 6ac283864533..cf2cbb17acbd 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -234,34 +234,42 @@ extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
int is_new);
struct md_cluster_info;
-/* change UNSUPPORTED_MDDEV_FLAGS for each array type if new flag is added */
+/**
+ * enum mddev_flags - md device flags.
+ * @MD_ARRAY_FIRST_USE: First use of array, needs initialization.
+ * @MD_CLOSING: If set, we are closing the array, do not open it then.
+ * @MD_JOURNAL_CLEAN: A raid with journal is already clean.
+ * @MD_HAS_JOURNAL: The raid array has journal feature set.
+ * @MD_CLUSTER_RESYNC_LOCKED: cluster raid only, which means node, already took
+ * resync lock, need to release the lock.
+ * @MD_FAILFAST_SUPPORTED: Using MD_FAILFAST on metadata writes is supported as
+ * calls to md_error() will never cause the array to
+ * become failed.
+ * @MD_HAS_PPL: The raid array has PPL feature set.
+ * @MD_HAS_MULTIPLE_PPLS: The raid array has multiple PPLs feature set.
+ * @MD_ALLOW_SB_UPDATE: md_check_recovery is allowed to update the metadata
+ * without taking reconfig_mutex.
+ * @MD_UPDATING_SB: md_check_recovery is updating the metadata without
+ * explicitly holding reconfig_mutex.
+ * @MD_NOT_READY: do_md_run() is active, so 'array_state', ust not report that
+ * array is ready yet.
+ * @MD_BROKEN: This is used to stop writes and mark array as failed.
+ *
+ * change UNSUPPORTED_MDDEV_FLAGS for each array type if new flag is added
+ */
enum mddev_flags {
- MD_ARRAY_FIRST_USE, /* First use of array, needs initialization */
- MD_CLOSING, /* If set, we are closing the array, do not open
- * it then */
- MD_JOURNAL_CLEAN, /* A raid with journal is already clean */
- MD_HAS_JOURNAL, /* The raid array has journal feature set */
- MD_CLUSTER_RESYNC_LOCKED, /* cluster raid only, which means node
- * already took resync lock, need to
- * release the lock */
- MD_FAILFAST_SUPPORTED, /* Using MD_FAILFAST on metadata writes is
- * supported as calls to md_error() will
- * never cause the array to become failed.
- */
- MD_HAS_PPL, /* The raid array has PPL feature set */
- MD_HAS_MULTIPLE_PPLS, /* The raid array has multiple PPLs feature set */
- MD_ALLOW_SB_UPDATE, /* md_check_recovery is allowed to update
- * the metadata without taking reconfig_mutex.
- */
- MD_UPDATING_SB, /* md_check_recovery is updating the metadata
- * without explicitly holding reconfig_mutex.
- */
- 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_ARRAY_FIRST_USE,
+ MD_CLOSING,
+ MD_JOURNAL_CLEAN,
+ MD_HAS_JOURNAL,
+ MD_CLUSTER_RESYNC_LOCKED,
+ MD_FAILFAST_SUPPORTED,
+ MD_HAS_PPL,
+ MD_HAS_MULTIPLE_PPLS,
+ MD_ALLOW_SB_UPDATE,
+ MD_UPDATING_SB,
+ MD_NOT_READY,
+ MD_BROKEN,
};
enum mddev_sb_flags {
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 5aed2c8b746e..99d5af1362d7 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1641,30 +1641,39 @@ static void raid1_status(struct seq_file *seq, struct mddev *mddev)
seq_printf(seq, "]");
}
+/**
+ * raid1_error() - RAID1 error handler.
+ * @mddev: affected md device.
+ * @rdev: member device to fail.
+ *
+ * The routine acknowledges &rdev failure and determines new @mddev state.
+ * If it failed, then:
+ * - &MD_BROKEN flag is set in &mddev->flags.
+ * - recovery is disabled.
+ * Otherwise, it must be degraded:
+ * - recovery is interrupted.
+ * - &mddev->degraded is bumped.
+ *
+ * @rdev is marked as &Faulty excluding case when array is failed and
+ * &mddev->fail_last_dev is off.
+ */
static void raid1_error(struct mddev *mddev, struct md_rdev *rdev)
{
char b[BDEVNAME_SIZE];
struct r1conf *conf = mddev->private;
unsigned long flags;
- /*
- * If it is not operational, then we have already marked it as dead
- * else if it is the last working disks with "fail_last_dev == false",
- * ignore the error, let the next level up know.
- * else mark the drive as failed
- */
spin_lock_irqsave(&conf->device_lock, flags);
- if (test_bit(In_sync, &rdev->flags) && !mddev->fail_last_dev
- && (conf->raid_disks - mddev->degraded) == 1) {
- /*
- * Don't fail the drive, act as though we were just a
- * normal single drive.
- * However don't try a recovery from this drive as
- * it is very likely to fail.
- */
- conf->recovery_disabled = mddev->recovery_disabled;
- spin_unlock_irqrestore(&conf->device_lock, flags);
- return;
+
+ if (test_bit(In_sync, &rdev->flags) &&
+ (conf->raid_disks - mddev->degraded) == 1) {
+ set_bit(MD_BROKEN, &mddev->flags);
+
+ if (!mddev->fail_last_dev) {
+ conf->recovery_disabled = mddev->recovery_disabled;
+ spin_unlock_irqrestore(&conf->device_lock, flags);
+ return;
+ }
}
set_bit(Blocked, &rdev->flags);
if (test_and_clear_bit(In_sync, &rdev->flags))
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 834eb3ba95a6..dfa576cdf11c 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1970,32 +1970,40 @@ static int enough(struct r10conf *conf, int ignore)
_enough(conf, 1, ignore);
}
+/**
+ * raid10_error() - RAID10 error handler.
+ * @mddev: affected md device.
+ * @rdev: member device to fail.
+ *
+ * The routine acknowledges &rdev failure and determines new @mddev state.
+ * If it failed, then:
+ * - &MD_BROKEN flag is set in &mddev->flags.
+ * Otherwise, it must be degraded:
+ * - recovery is interrupted.
+ * - &mddev->degraded is bumped.
+
+ * @rdev is marked as &Faulty excluding case when array is failed and
+ * &mddev->fail_last_dev is off.
+ */
static void raid10_error(struct mddev *mddev, struct md_rdev *rdev)
{
char b[BDEVNAME_SIZE];
struct r10conf *conf = mddev->private;
unsigned long flags;
- /*
- * If it is not operational, then we have already marked it as dead
- * else if it is the last working disks with "fail_last_dev == false",
- * ignore the error, let the next level up know.
- * else mark the drive as failed
- */
spin_lock_irqsave(&conf->device_lock, flags);
- if (test_bit(In_sync, &rdev->flags) && !mddev->fail_last_dev
- && !enough(conf, rdev->raid_disk)) {
- /*
- * Don't fail the drive, just return an IO error.
- */
- spin_unlock_irqrestore(&conf->device_lock, flags);
- return;
+
+ if (test_bit(In_sync, &rdev->flags) && !enough(conf, rdev->raid_disk)) {
+ set_bit(MD_BROKEN, &mddev->flags);
+
+ if (!mddev->fail_last_dev) {
+ spin_unlock_irqrestore(&conf->device_lock, flags);
+ return;
+ }
}
if (test_and_clear_bit(In_sync, &rdev->flags))
mddev->degraded++;
- /*
- * If recovery is running, make sure it aborts.
- */
+
set_bit(MD_RECOVERY_INTR, &mddev->recovery);
set_bit(Blocked, &rdev->flags);
set_bit(Faulty, &rdev->flags);
--
2.35.3