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-rw-r--r--drivers/md/raid1.c199
1 files changed, 105 insertions, 94 deletions
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index e138922d51..750a802478 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -600,16 +600,13 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
const sector_t this_sector = r1_bio->sector;
int sectors;
int best_good_sectors;
- int best_disk, best_dist_disk, best_pending_disk;
- int has_nonrot_disk;
+ int best_disk, best_dist_disk, best_pending_disk, sequential_disk;
int disk;
sector_t best_dist;
unsigned int min_pending;
struct md_rdev *rdev;
int choose_first;
- int choose_next_idle;
- rcu_read_lock();
/*
* Check if we can balance. We can balance on the whole
* device if no resync is going on, or below the resync window.
@@ -619,12 +616,11 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
sectors = r1_bio->sectors;
best_disk = -1;
best_dist_disk = -1;
+ sequential_disk = -1;
best_dist = MaxSector;
best_pending_disk = -1;
min_pending = UINT_MAX;
best_good_sectors = 0;
- has_nonrot_disk = 0;
- choose_next_idle = 0;
clear_bit(R1BIO_FailFast, &r1_bio->state);
if ((conf->mddev->recovery_cp < this_sector + sectors) ||
@@ -640,9 +636,8 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
sector_t first_bad;
int bad_sectors;
unsigned int pending;
- bool nonrot;
- rdev = rcu_dereference(conf->mirrors[disk].rdev);
+ rdev = conf->mirrors[disk].rdev;
if (r1_bio->bios[disk] == IO_BLOCKED
|| rdev == NULL
|| test_bit(Faulty, &rdev->flags))
@@ -706,8 +701,6 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
/* At least two disks to choose from so failfast is OK */
set_bit(R1BIO_FailFast, &r1_bio->state);
- nonrot = bdev_nonrot(rdev->bdev);
- has_nonrot_disk |= nonrot;
pending = atomic_read(&rdev->nr_pending);
dist = abs(this_sector - conf->mirrors[disk].head_position);
if (choose_first) {
@@ -720,7 +713,6 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
int opt_iosize = bdev_io_opt(rdev->bdev) >> 9;
struct raid1_info *mirror = &conf->mirrors[disk];
- best_disk = disk;
/*
* If buffered sequential IO size exceeds optimal
* iosize, check if there is idle disk. If yes, choose
@@ -734,20 +726,27 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
* small, but not a big deal since when the second disk
* starts IO, the first disk is likely still busy.
*/
- if (nonrot && opt_iosize > 0 &&
+ if (test_bit(Nonrot, &rdev->flags) && opt_iosize > 0 &&
mirror->seq_start != MaxSector &&
mirror->next_seq_sect > opt_iosize &&
mirror->next_seq_sect - opt_iosize >=
mirror->seq_start) {
- choose_next_idle = 1;
- continue;
+ /*
+ * Add 'pending' to avoid choosing this disk if
+ * there is other idle disk.
+ */
+ pending++;
+ /*
+ * If there is no other idle disk, this disk
+ * will be chosen.
+ */
+ sequential_disk = disk;
+ } else {
+ best_disk = disk;
+ break;
}
- break;
}
- if (choose_next_idle)
- continue;
-
if (min_pending > pending) {
min_pending = pending;
best_pending_disk = disk;
@@ -760,20 +759,27 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
}
/*
+ * sequential IO size exceeds optimal iosize, however, there is no other
+ * idle disk, so choose the sequential disk.
+ */
+ if (best_disk == -1 && min_pending != 0)
+ best_disk = sequential_disk;
+
+ /*
* If all disks are rotational, choose the closest disk. If any disk is
* non-rotational, choose the disk with less pending request even the
* disk is rotational, which might/might not be optimal for raids with
* mixed ratation/non-rotational disks depending on workload.
*/
if (best_disk == -1) {
- if (has_nonrot_disk || min_pending == 0)
+ if (READ_ONCE(conf->nonrot_disks) || min_pending == 0)
best_disk = best_pending_disk;
else
best_disk = best_dist_disk;
}
if (best_disk >= 0) {
- rdev = rcu_dereference(conf->mirrors[best_disk].rdev);
+ rdev = conf->mirrors[best_disk].rdev;
if (!rdev)
goto retry;
atomic_inc(&rdev->nr_pending);
@@ -784,7 +790,6 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
conf->mirrors[best_disk].next_seq_sect = this_sector + sectors;
}
- rcu_read_unlock();
*max_sectors = sectors;
return best_disk;
@@ -1235,14 +1240,12 @@ static void raid1_read_request(struct mddev *mddev, struct bio *bio,
if (r1bio_existed) {
/* Need to get the block device name carefully */
- struct md_rdev *rdev;
- rcu_read_lock();
- rdev = rcu_dereference(conf->mirrors[r1_bio->read_disk].rdev);
+ struct md_rdev *rdev = conf->mirrors[r1_bio->read_disk].rdev;
+
if (rdev)
snprintf(b, sizeof(b), "%pg", rdev->bdev);
else
strcpy(b, "???");
- rcu_read_unlock();
}
/*
@@ -1396,10 +1399,9 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio,
disks = conf->raid_disks * 2;
blocked_rdev = NULL;
- rcu_read_lock();
max_sectors = r1_bio->sectors;
for (i = 0; i < disks; i++) {
- struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
+ struct md_rdev *rdev = conf->mirrors[i].rdev;
/*
* The write-behind io is only attempted on drives marked as
@@ -1465,7 +1467,6 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio,
}
r1_bio->bios[i] = bio;
}
- rcu_read_unlock();
if (unlikely(blocked_rdev)) {
/* Wait for this device to become unblocked */
@@ -1617,15 +1618,16 @@ static void raid1_status(struct seq_file *seq, struct mddev *mddev)
struct r1conf *conf = mddev->private;
int i;
+ lockdep_assert_held(&mddev->lock);
+
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->mirrors[i].rdev);
+ struct md_rdev *rdev = READ_ONCE(conf->mirrors[i].rdev);
+
seq_printf(seq, "%s",
rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
}
- rcu_read_unlock();
seq_printf(seq, "]");
}
@@ -1691,16 +1693,15 @@ static void print_conf(struct r1conf *conf)
pr_debug(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
conf->raid_disks);
- rcu_read_lock();
+ lockdep_assert_held(&conf->mddev->reconfig_mutex);
for (i = 0; i < conf->raid_disks; i++) {
- struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
+ struct md_rdev *rdev = conf->mirrors[i].rdev;
if (rdev)
pr_debug(" disk %d, wo:%d, o:%d, dev:%pg\n",
i, !test_bit(In_sync, &rdev->flags),
!test_bit(Faulty, &rdev->flags),
rdev->bdev);
}
- rcu_read_unlock();
}
static void close_sync(struct r1conf *conf)
@@ -1767,6 +1768,52 @@ static int raid1_spare_active(struct mddev *mddev)
return count;
}
+static bool raid1_add_conf(struct r1conf *conf, struct md_rdev *rdev, int disk,
+ bool replacement)
+{
+ struct raid1_info *info = conf->mirrors + disk;
+
+ if (replacement)
+ info += conf->raid_disks;
+
+ if (info->rdev)
+ return false;
+
+ if (bdev_nonrot(rdev->bdev)) {
+ set_bit(Nonrot, &rdev->flags);
+ WRITE_ONCE(conf->nonrot_disks, conf->nonrot_disks + 1);
+ }
+
+ rdev->raid_disk = disk;
+ info->head_position = 0;
+ info->seq_start = MaxSector;
+ WRITE_ONCE(info->rdev, rdev);
+
+ return true;
+}
+
+static bool raid1_remove_conf(struct r1conf *conf, int disk)
+{
+ struct raid1_info *info = conf->mirrors + disk;
+ struct md_rdev *rdev = info->rdev;
+
+ if (!rdev || test_bit(In_sync, &rdev->flags) ||
+ atomic_read(&rdev->nr_pending))
+ return false;
+
+ /* Only remove non-faulty devices if recovery is not possible. */
+ if (!test_bit(Faulty, &rdev->flags) &&
+ rdev->mddev->recovery_disabled != conf->recovery_disabled &&
+ rdev->mddev->degraded < conf->raid_disks)
+ return false;
+
+ if (test_and_clear_bit(Nonrot, &rdev->flags))
+ WRITE_ONCE(conf->nonrot_disks, conf->nonrot_disks - 1);
+
+ WRITE_ONCE(info->rdev, NULL);
+ return true;
+}
+
static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
{
struct r1conf *conf = mddev->private;
@@ -1802,15 +1849,13 @@ static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
disk_stack_limits(mddev->gendisk, rdev->bdev,
rdev->data_offset << 9);
- p->head_position = 0;
- rdev->raid_disk = mirror;
+ raid1_add_conf(conf, rdev, mirror, false);
err = 0;
/* As all devices are equivalent, we don't need a full recovery
* if this was recently any drive of the array
*/
if (rdev->saved_raid_disk < 0)
conf->fullsync = 1;
- rcu_assign_pointer(p->rdev, rdev);
break;
}
if (test_bit(WantReplacement, &p->rdev->flags) &&
@@ -1820,13 +1865,11 @@ static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
if (err && repl_slot >= 0) {
/* Add this device as a replacement */
- p = conf->mirrors + repl_slot;
clear_bit(In_sync, &rdev->flags);
set_bit(Replacement, &rdev->flags);
- rdev->raid_disk = repl_slot;
+ raid1_add_conf(conf, rdev, repl_slot, true);
err = 0;
conf->fullsync = 1;
- rcu_assign_pointer(p[conf->raid_disks].rdev, rdev);
}
print_conf(conf);
@@ -1843,36 +1886,20 @@ static int raid1_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
if (unlikely(number >= conf->raid_disks))
goto abort;
- if (rdev != p->rdev)
- p = conf->mirrors + conf->raid_disks + number;
+ if (rdev != p->rdev) {
+ number += conf->raid_disks;
+ p = conf->mirrors + number;
+ }
print_conf(conf);
if (rdev == p->rdev) {
- if (test_bit(In_sync, &rdev->flags) ||
- atomic_read(&rdev->nr_pending)) {
+ if (!raid1_remove_conf(conf, number)) {
err = -EBUSY;
goto abort;
}
- /* Only remove non-faulty devices if recovery
- * is not possible.
- */
- if (!test_bit(Faulty, &rdev->flags) &&
- mddev->recovery_disabled != conf->recovery_disabled &&
- mddev->degraded < conf->raid_disks) {
- err = -EBUSY;
- goto abort;
- }
- p->rdev = NULL;
- if (!test_bit(RemoveSynchronized, &rdev->flags)) {
- synchronize_rcu();
- if (atomic_read(&rdev->nr_pending)) {
- /* lost the race, try later */
- err = -EBUSY;
- p->rdev = rdev;
- goto abort;
- }
- }
- if (conf->mirrors[conf->raid_disks + number].rdev) {
+
+ if (number < conf->raid_disks &&
+ conf->mirrors[conf->raid_disks + number].rdev) {
/* We just removed a device that is being replaced.
* Move down the replacement. We drain all IO before
* doing this to avoid confusion.
@@ -1892,7 +1919,7 @@ static int raid1_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
goto abort;
}
clear_bit(Replacement, &repl->flags);
- p->rdev = repl;
+ WRITE_ONCE(p->rdev, repl);
conf->mirrors[conf->raid_disks + number].rdev = NULL;
unfreeze_array(conf);
}
@@ -2290,8 +2317,7 @@ static void fix_read_error(struct r1conf *conf, int read_disk,
sector_t first_bad;
int bad_sectors;
- rcu_read_lock();
- rdev = rcu_dereference(conf->mirrors[d].rdev);
+ rdev = conf->mirrors[d].rdev;
if (rdev &&
(test_bit(In_sync, &rdev->flags) ||
(!test_bit(Faulty, &rdev->flags) &&
@@ -2299,15 +2325,14 @@ static void fix_read_error(struct r1conf *conf, int read_disk,
is_badblock(rdev, sect, s,
&first_bad, &bad_sectors) == 0) {
atomic_inc(&rdev->nr_pending);
- rcu_read_unlock();
if (sync_page_io(rdev, sect, s<<9,
conf->tmppage, REQ_OP_READ, false))
success = 1;
rdev_dec_pending(rdev, mddev);
if (success)
break;
- } else
- rcu_read_unlock();
+ }
+
d++;
if (d == conf->raid_disks * 2)
d = 0;
@@ -2326,29 +2351,24 @@ static void fix_read_error(struct r1conf *conf, int read_disk,
if (d==0)
d = conf->raid_disks * 2;
d--;
- rcu_read_lock();
- rdev = rcu_dereference(conf->mirrors[d].rdev);
+ rdev = conf->mirrors[d].rdev;
if (rdev &&
!test_bit(Faulty, &rdev->flags)) {
atomic_inc(&rdev->nr_pending);
- rcu_read_unlock();
r1_sync_page_io(rdev, sect, s,
conf->tmppage, REQ_OP_WRITE);
rdev_dec_pending(rdev, mddev);
- } else
- rcu_read_unlock();
+ }
}
d = start;
while (d != read_disk) {
if (d==0)
d = conf->raid_disks * 2;
d--;
- rcu_read_lock();
- rdev = rcu_dereference(conf->mirrors[d].rdev);
+ rdev = conf->mirrors[d].rdev;
if (rdev &&
!test_bit(Faulty, &rdev->flags)) {
atomic_inc(&rdev->nr_pending);
- rcu_read_unlock();
if (r1_sync_page_io(rdev, sect, s,
conf->tmppage, REQ_OP_READ)) {
atomic_add(s, &rdev->corrected_errors);
@@ -2359,8 +2379,7 @@ static void fix_read_error(struct r1conf *conf, int read_disk,
rdev->bdev);
}
rdev_dec_pending(rdev, mddev);
- } else
- rcu_read_unlock();
+ }
}
sectors -= s;
sect += s;
@@ -2741,7 +2760,6 @@ static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr,
r1_bio = raid1_alloc_init_r1buf(conf);
- rcu_read_lock();
/*
* If we get a correctably read error during resync or recovery,
* we might want to read from a different device. So we
@@ -2762,7 +2780,7 @@ static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr,
struct md_rdev *rdev;
bio = r1_bio->bios[i];
- rdev = rcu_dereference(conf->mirrors[i].rdev);
+ rdev = conf->mirrors[i].rdev;
if (rdev == NULL ||
test_bit(Faulty, &rdev->flags)) {
if (i < conf->raid_disks)
@@ -2820,7 +2838,6 @@ static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr,
bio->bi_opf |= MD_FAILFAST;
}
}
- rcu_read_unlock();
if (disk < 0)
disk = wonly;
r1_bio->read_disk = disk;
@@ -3025,23 +3042,17 @@ static struct r1conf *setup_conf(struct mddev *mddev)
err = -EINVAL;
spin_lock_init(&conf->device_lock);
+ conf->raid_disks = mddev->raid_disks;
rdev_for_each(rdev, mddev) {
int disk_idx = rdev->raid_disk;
- if (disk_idx >= mddev->raid_disks
- || disk_idx < 0)
+
+ if (disk_idx >= conf->raid_disks || disk_idx < 0)
continue;
- if (test_bit(Replacement, &rdev->flags))
- disk = conf->mirrors + mddev->raid_disks + disk_idx;
- else
- disk = conf->mirrors + disk_idx;
- if (disk->rdev)
+ if (!raid1_add_conf(conf, rdev, disk_idx,
+ test_bit(Replacement, &rdev->flags)))
goto abort;
- disk->rdev = rdev;
- disk->head_position = 0;
- disk->seq_start = MaxSector;
}
- conf->raid_disks = mddev->raid_disks;
conf->mddev = mddev;
INIT_LIST_HEAD(&conf->retry_list);
INIT_LIST_HEAD(&conf->bio_end_io_list);