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path: root/drivers/md/raid5.c
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Diffstat (limited to 'drivers/md/raid5.c')
-rw-r--r--drivers/md/raid5.c203
1 files changed, 61 insertions, 142 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 26e1e8a5e941..8497880135ee 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -36,7 +36,6 @@
*/
#include <linux/blkdev.h>
-#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/raid/pq.h>
#include <linux/async_tx.h>
@@ -694,12 +693,12 @@ int raid5_calc_degraded(struct r5conf *conf)
int degraded, degraded2;
int i;
- rcu_read_lock();
degraded = 0;
for (i = 0; i < conf->previous_raid_disks; i++) {
- struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
+ struct md_rdev *rdev = READ_ONCE(conf->disks[i].rdev);
+
if (rdev && test_bit(Faulty, &rdev->flags))
- rdev = rcu_dereference(conf->disks[i].replacement);
+ rdev = READ_ONCE(conf->disks[i].replacement);
if (!rdev || test_bit(Faulty, &rdev->flags))
degraded++;
else if (test_bit(In_sync, &rdev->flags))
@@ -717,15 +716,14 @@ int raid5_calc_degraded(struct r5conf *conf)
if (conf->raid_disks >= conf->previous_raid_disks)
degraded++;
}
- rcu_read_unlock();
if (conf->raid_disks == conf->previous_raid_disks)
return degraded;
- rcu_read_lock();
degraded2 = 0;
for (i = 0; i < conf->raid_disks; i++) {
- struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
+ struct md_rdev *rdev = READ_ONCE(conf->disks[i].rdev);
+
if (rdev && test_bit(Faulty, &rdev->flags))
- rdev = rcu_dereference(conf->disks[i].replacement);
+ rdev = READ_ONCE(conf->disks[i].replacement);
if (!rdev || test_bit(Faulty, &rdev->flags))
degraded2++;
else if (test_bit(In_sync, &rdev->flags))
@@ -739,7 +737,6 @@ int raid5_calc_degraded(struct r5conf *conf)
if (conf->raid_disks <= conf->previous_raid_disks)
degraded2++;
}
- rcu_read_unlock();
if (degraded2 > degraded)
return degraded2;
return degraded;
@@ -1184,14 +1181,8 @@ again:
bi = &dev->req;
rbi = &dev->rreq; /* For writing to replacement */
- rcu_read_lock();
- rrdev = rcu_dereference(conf->disks[i].replacement);
- smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
- rdev = rcu_dereference(conf->disks[i].rdev);
- if (!rdev) {
- rdev = rrdev;
- rrdev = NULL;
- }
+ rdev = conf->disks[i].rdev;
+ rrdev = conf->disks[i].replacement;
if (op_is_write(op)) {
if (replace_only)
rdev = NULL;
@@ -1212,7 +1203,6 @@ again:
rrdev = NULL;
if (rrdev)
atomic_inc(&rrdev->nr_pending);
- rcu_read_unlock();
/* We have already checked bad blocks for reads. Now
* need to check for writes. We never accept write errors
@@ -2731,28 +2721,6 @@ static void shrink_stripes(struct r5conf *conf)
conf->slab_cache = NULL;
}
-/*
- * This helper wraps rcu_dereference_protected() and can be used when
- * it is known that the nr_pending of the rdev is elevated.
- */
-static struct md_rdev *rdev_pend_deref(struct md_rdev __rcu *rdev)
-{
- return rcu_dereference_protected(rdev,
- atomic_read(&rcu_access_pointer(rdev)->nr_pending));
-}
-
-/*
- * This helper wraps rcu_dereference_protected() and should be used
- * when it is known that the mddev_lock() is held. This is safe
- * seeing raid5_remove_disk() has the same lock held.
- */
-static struct md_rdev *rdev_mdlock_deref(struct mddev *mddev,
- struct md_rdev __rcu *rdev)
-{
- return rcu_dereference_protected(rdev,
- lockdep_is_held(&mddev->reconfig_mutex));
-}
-
static void raid5_end_read_request(struct bio * bi)
{
struct stripe_head *sh = bi->bi_private;
@@ -2778,9 +2746,9 @@ static void raid5_end_read_request(struct bio * bi)
* In that case it moved down to 'rdev'.
* rdev is not removed until all requests are finished.
*/
- rdev = rdev_pend_deref(conf->disks[i].replacement);
+ rdev = conf->disks[i].replacement;
if (!rdev)
- rdev = rdev_pend_deref(conf->disks[i].rdev);
+ rdev = conf->disks[i].rdev;
if (use_new_offset(conf, sh))
s = sh->sector + rdev->new_data_offset;
@@ -2893,11 +2861,11 @@ static void raid5_end_write_request(struct bio *bi)
for (i = 0 ; i < disks; i++) {
if (bi == &sh->dev[i].req) {
- rdev = rdev_pend_deref(conf->disks[i].rdev);
+ rdev = conf->disks[i].rdev;
break;
}
if (bi == &sh->dev[i].rreq) {
- rdev = rdev_pend_deref(conf->disks[i].replacement);
+ rdev = conf->disks[i].replacement;
if (rdev)
replacement = 1;
else
@@ -2905,7 +2873,7 @@ static void raid5_end_write_request(struct bio *bi)
* replaced it. rdev is not removed
* until all requests are finished.
*/
- rdev = rdev_pend_deref(conf->disks[i].rdev);
+ rdev = conf->disks[i].rdev;
break;
}
}
@@ -3667,15 +3635,13 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
int bitmap_end = 0;
if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
- struct md_rdev *rdev;
- rcu_read_lock();
- rdev = rcu_dereference(conf->disks[i].rdev);
+ struct md_rdev *rdev = conf->disks[i].rdev;
+
if (rdev && test_bit(In_sync, &rdev->flags) &&
!test_bit(Faulty, &rdev->flags))
atomic_inc(&rdev->nr_pending);
else
rdev = NULL;
- rcu_read_unlock();
if (rdev) {
if (!rdev_set_badblocks(
rdev,
@@ -3793,16 +3759,17 @@ handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
/* During recovery devices cannot be removed, so
* locking and refcounting of rdevs is not needed
*/
- rcu_read_lock();
for (i = 0; i < conf->raid_disks; i++) {
- struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
+ struct md_rdev *rdev = conf->disks[i].rdev;
+
if (rdev
&& !test_bit(Faulty, &rdev->flags)
&& !test_bit(In_sync, &rdev->flags)
&& !rdev_set_badblocks(rdev, sh->sector,
RAID5_STRIPE_SECTORS(conf), 0))
abort = 1;
- rdev = rcu_dereference(conf->disks[i].replacement);
+ rdev = conf->disks[i].replacement;
+
if (rdev
&& !test_bit(Faulty, &rdev->flags)
&& !test_bit(In_sync, &rdev->flags)
@@ -3810,7 +3777,6 @@ handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
RAID5_STRIPE_SECTORS(conf), 0))
abort = 1;
}
- rcu_read_unlock();
if (abort)
conf->recovery_disabled =
conf->mddev->recovery_disabled;
@@ -3823,15 +3789,13 @@ static int want_replace(struct stripe_head *sh, int disk_idx)
struct md_rdev *rdev;
int rv = 0;
- rcu_read_lock();
- rdev = rcu_dereference(sh->raid_conf->disks[disk_idx].replacement);
+ rdev = sh->raid_conf->disks[disk_idx].replacement;
if (rdev
&& !test_bit(Faulty, &rdev->flags)
&& !test_bit(In_sync, &rdev->flags)
&& (rdev->recovery_offset <= sh->sector
|| rdev->mddev->recovery_cp <= sh->sector))
rv = 1;
- rcu_read_unlock();
return rv;
}
@@ -4708,7 +4672,6 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
s->log_failed = r5l_log_disk_error(conf);
/* Now to look around and see what can be done */
- rcu_read_lock();
for (i=disks; i--; ) {
struct md_rdev *rdev;
sector_t first_bad;
@@ -4753,7 +4716,7 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
/* Prefer to use the replacement for reads, but only
* if it is recovered enough and has no bad blocks.
*/
- rdev = rcu_dereference(conf->disks[i].replacement);
+ rdev = conf->disks[i].replacement;
if (rdev && !test_bit(Faulty, &rdev->flags) &&
rdev->recovery_offset >= sh->sector + RAID5_STRIPE_SECTORS(conf) &&
!is_badblock(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf),
@@ -4764,7 +4727,7 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
set_bit(R5_NeedReplace, &dev->flags);
else
clear_bit(R5_NeedReplace, &dev->flags);
- rdev = rcu_dereference(conf->disks[i].rdev);
+ rdev = conf->disks[i].rdev;
clear_bit(R5_ReadRepl, &dev->flags);
}
if (rdev && test_bit(Faulty, &rdev->flags))
@@ -4811,8 +4774,8 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
if (test_bit(R5_WriteError, &dev->flags)) {
/* This flag does not apply to '.replacement'
* only to .rdev, so make sure to check that*/
- struct md_rdev *rdev2 = rcu_dereference(
- conf->disks[i].rdev);
+ struct md_rdev *rdev2 = conf->disks[i].rdev;
+
if (rdev2 == rdev)
clear_bit(R5_Insync, &dev->flags);
if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
@@ -4824,8 +4787,8 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
if (test_bit(R5_MadeGood, &dev->flags)) {
/* This flag does not apply to '.replacement'
* only to .rdev, so make sure to check that*/
- struct md_rdev *rdev2 = rcu_dereference(
- conf->disks[i].rdev);
+ struct md_rdev *rdev2 = conf->disks[i].rdev;
+
if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
s->handle_bad_blocks = 1;
atomic_inc(&rdev2->nr_pending);
@@ -4833,8 +4796,8 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
clear_bit(R5_MadeGood, &dev->flags);
}
if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
- struct md_rdev *rdev2 = rcu_dereference(
- conf->disks[i].replacement);
+ struct md_rdev *rdev2 = conf->disks[i].replacement;
+
if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
s->handle_bad_blocks = 1;
atomic_inc(&rdev2->nr_pending);
@@ -4855,8 +4818,7 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
if (rdev && !test_bit(Faulty, &rdev->flags))
do_recovery = 1;
else if (!rdev) {
- rdev = rcu_dereference(
- conf->disks[i].replacement);
+ rdev = conf->disks[i].replacement;
if (rdev && !test_bit(Faulty, &rdev->flags))
do_recovery = 1;
}
@@ -4883,7 +4845,6 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
else
s->replacing = 1;
}
- rcu_read_unlock();
}
/*
@@ -5340,23 +5301,23 @@ finish:
struct r5dev *dev = &sh->dev[i];
if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
/* We own a safe reference to the rdev */
- rdev = rdev_pend_deref(conf->disks[i].rdev);
+ rdev = conf->disks[i].rdev;
if (!rdev_set_badblocks(rdev, sh->sector,
RAID5_STRIPE_SECTORS(conf), 0))
md_error(conf->mddev, rdev);
rdev_dec_pending(rdev, conf->mddev);
}
if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
- rdev = rdev_pend_deref(conf->disks[i].rdev);
+ rdev = conf->disks[i].rdev;
rdev_clear_badblocks(rdev, sh->sector,
RAID5_STRIPE_SECTORS(conf), 0);
rdev_dec_pending(rdev, conf->mddev);
}
if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
- rdev = rdev_pend_deref(conf->disks[i].replacement);
+ rdev = conf->disks[i].replacement;
if (!rdev)
/* rdev have been moved down */
- rdev = rdev_pend_deref(conf->disks[i].rdev);
+ rdev = conf->disks[i].rdev;
rdev_clear_badblocks(rdev, sh->sector,
RAID5_STRIPE_SECTORS(conf), 0);
rdev_dec_pending(rdev, conf->mddev);
@@ -5515,24 +5476,22 @@ static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
&dd_idx, NULL);
end_sector = sector + bio_sectors(raid_bio);
- rcu_read_lock();
if (r5c_big_stripe_cached(conf, sector))
- goto out_rcu_unlock;
+ return 0;
- rdev = rcu_dereference(conf->disks[dd_idx].replacement);
+ rdev = conf->disks[dd_idx].replacement;
if (!rdev || test_bit(Faulty, &rdev->flags) ||
rdev->recovery_offset < end_sector) {
- rdev = rcu_dereference(conf->disks[dd_idx].rdev);
+ rdev = conf->disks[dd_idx].rdev;
if (!rdev)
- goto out_rcu_unlock;
+ return 0;
if (test_bit(Faulty, &rdev->flags) ||
!(test_bit(In_sync, &rdev->flags) ||
rdev->recovery_offset >= end_sector))
- goto out_rcu_unlock;
+ return 0;
}
atomic_inc(&rdev->nr_pending);
- rcu_read_unlock();
if (is_badblock(rdev, sector, bio_sectors(raid_bio), &first_bad,
&bad_sectors)) {
@@ -5576,10 +5535,6 @@ static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
raid_bio->bi_iter.bi_sector);
submit_bio_noacct(align_bio);
return 1;
-
-out_rcu_unlock:
- rcu_read_unlock();
- return 0;
}
static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
@@ -6582,14 +6537,12 @@ static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_n
* Note in case of > 1 drive failures it's possible we're rebuilding
* one drive while leaving another faulty drive in array.
*/
- rcu_read_lock();
for (i = 0; i < conf->raid_disks; i++) {
- struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
+ struct md_rdev *rdev = conf->disks[i].rdev;
if (rdev == NULL || test_bit(Faulty, &rdev->flags))
still_degraded = 1;
}
- rcu_read_unlock();
md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
@@ -6820,18 +6773,7 @@ static void raid5d(struct md_thread *thread)
spin_unlock_irq(&conf->device_lock);
md_check_recovery(mddev);
spin_lock_irq(&conf->device_lock);
-
- /*
- * Waiting on MD_SB_CHANGE_PENDING below may deadlock
- * seeing md_check_recovery() is needed to clear
- * the flag when using mdmon.
- */
- continue;
}
-
- wait_event_lock_irq(mddev->sb_wait,
- !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
- conf->device_lock);
}
pr_debug("%d stripes handled\n", handled);
@@ -7911,18 +7853,10 @@ static int raid5_run(struct mddev *mddev)
for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
i++) {
- rdev = rdev_mdlock_deref(mddev, conf->disks[i].rdev);
- if (!rdev && conf->disks[i].replacement) {
- /* The replacement is all we have yet */
- rdev = rdev_mdlock_deref(mddev,
- conf->disks[i].replacement);
- conf->disks[i].replacement = NULL;
- clear_bit(Replacement, &rdev->flags);
- rcu_assign_pointer(conf->disks[i].rdev, rdev);
- }
+ rdev = conf->disks[i].rdev;
if (!rdev)
continue;
- if (rcu_access_pointer(conf->disks[i].replacement) &&
+ if (conf->disks[i].replacement &&
conf->reshape_progress != MaxSector) {
/* replacements and reshape simply do not mix. */
pr_warn("md: cannot handle concurrent replacement and reshape.\n");
@@ -8106,15 +8040,16 @@ static void raid5_status(struct seq_file *seq, struct mddev *mddev)
struct r5conf *conf = mddev->private;
int i;
+ lockdep_assert_held(&mddev->lock);
+
seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
conf->chunk_sectors / 2, mddev->layout);
seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
- rcu_read_lock();
for (i = 0; i < conf->raid_disks; i++) {
- struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
+ struct md_rdev *rdev = READ_ONCE(conf->disks[i].rdev);
+
seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
}
- rcu_read_unlock();
seq_printf (seq, "]");
}
@@ -8152,9 +8087,8 @@ static int raid5_spare_active(struct mddev *mddev)
unsigned long flags;
for (i = 0; i < conf->raid_disks; i++) {
- rdev = rdev_mdlock_deref(mddev, conf->disks[i].rdev);
- replacement = rdev_mdlock_deref(mddev,
- conf->disks[i].replacement);
+ rdev = conf->disks[i].rdev;
+ replacement = conf->disks[i].replacement;
if (replacement
&& replacement->recovery_offset == MaxSector
&& !test_bit(Faulty, &replacement->flags)
@@ -8193,7 +8127,7 @@ static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
struct r5conf *conf = mddev->private;
int err = 0;
int number = rdev->raid_disk;
- struct md_rdev __rcu **rdevp;
+ struct md_rdev **rdevp;
struct disk_info *p;
struct md_rdev *tmp;
@@ -8216,9 +8150,9 @@ static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
if (unlikely(number >= conf->pool_size))
return 0;
p = conf->disks + number;
- if (rdev == rcu_access_pointer(p->rdev))
+ if (rdev == p->rdev)
rdevp = &p->rdev;
- else if (rdev == rcu_access_pointer(p->replacement))
+ else if (rdev == p->replacement)
rdevp = &p->replacement;
else
return 0;
@@ -8238,37 +8172,24 @@ static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
if (!test_bit(Faulty, &rdev->flags) &&
mddev->recovery_disabled != conf->recovery_disabled &&
!has_failed(conf) &&
- (!rcu_access_pointer(p->replacement) ||
- rcu_access_pointer(p->replacement) == rdev) &&
+ (!p->replacement || p->replacement == rdev) &&
number < conf->raid_disks) {
err = -EBUSY;
goto abort;
}
- *rdevp = NULL;
- if (!test_bit(RemoveSynchronized, &rdev->flags)) {
- lockdep_assert_held(&mddev->reconfig_mutex);
- synchronize_rcu();
- if (atomic_read(&rdev->nr_pending)) {
- /* lost the race, try later */
- err = -EBUSY;
- rcu_assign_pointer(*rdevp, rdev);
- }
- }
+ WRITE_ONCE(*rdevp, NULL);
if (!err) {
err = log_modify(conf, rdev, false);
if (err)
goto abort;
}
- tmp = rcu_access_pointer(p->replacement);
+ tmp = p->replacement;
if (tmp) {
/* We must have just cleared 'rdev' */
- rcu_assign_pointer(p->rdev, tmp);
+ WRITE_ONCE(p->rdev, tmp);
clear_bit(Replacement, &tmp->flags);
- smp_mb(); /* Make sure other CPUs may see both as identical
- * but will never see neither - if they are careful
- */
- rcu_assign_pointer(p->replacement, NULL);
+ WRITE_ONCE(p->replacement, NULL);
if (!err)
err = log_modify(conf, tmp, true);
@@ -8336,7 +8257,7 @@ static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
rdev->raid_disk = disk;
if (rdev->saved_raid_disk != disk)
conf->fullsync = 1;
- rcu_assign_pointer(p->rdev, rdev);
+ WRITE_ONCE(p->rdev, rdev);
err = log_modify(conf, rdev, true);
@@ -8345,7 +8266,7 @@ static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
}
for (disk = first; disk <= last; disk++) {
p = conf->disks + disk;
- tmp = rdev_mdlock_deref(mddev, p->rdev);
+ tmp = p->rdev;
if (test_bit(WantReplacement, &tmp->flags) &&
mddev->reshape_position == MaxSector &&
p->replacement == NULL) {
@@ -8354,7 +8275,7 @@ static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
rdev->raid_disk = disk;
err = 0;
conf->fullsync = 1;
- rcu_assign_pointer(p->replacement, rdev);
+ WRITE_ONCE(p->replacement, rdev);
break;
}
}
@@ -8487,7 +8408,7 @@ static int raid5_start_reshape(struct mddev *mddev)
if (mddev->recovery_cp < MaxSector)
return -EBUSY;
for (i = 0; i < conf->raid_disks; i++)
- if (rdev_mdlock_deref(mddev, conf->disks[i].replacement))
+ if (conf->disks[i].replacement)
return -EBUSY;
rdev_for_each(rdev, mddev) {
@@ -8658,12 +8579,10 @@ static void raid5_finish_reshape(struct mddev *mddev)
for (d = conf->raid_disks ;
d < conf->raid_disks - mddev->delta_disks;
d++) {
- rdev = rdev_mdlock_deref(mddev,
- conf->disks[d].rdev);
+ rdev = conf->disks[d].rdev;
if (rdev)
clear_bit(In_sync, &rdev->flags);
- rdev = rdev_mdlock_deref(mddev,
- conf->disks[d].replacement);
+ rdev = conf->disks[d].replacement;
if (rdev)
clear_bit(In_sync, &rdev->flags);
}