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Merge branch 'md-next-rcu-cleanup' into md-next

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From Yu Kuai:

md: remove rcu protection to access rdev from conf

The lifetime of rdev:

1. md_import_device() generate a rdev based on underlying disk;

   mddev_lock()
   rdev = kzalloc();
   rdev->bdev = blkdev_get_by_dev();
   mddev_unlock()

2. bind_rdev_to_array() add this rdev to mddev->disks;

   mddev_lock()
   kobject_add(&rdev->kobj, &mddev->kobj, ...);
   list_add_rcu(&rdev->same_set, &mddev->disks);
   mddev_unlock()

3. remove_and_add_spares() add this rdev to conf;

   mddev_lock()
   rdev_addable();
   pers->hot_add_disk();
   rcu_assign_pointer(conf->rdev, rdev);
   mddev_unlock()

4. Use this array with rdev;

5. remove_and_add_spares() remove rdev from conf;

   // triggered by sysfs/ioctl
   mddev_lock()
   rdev_removeable();
   pers->hot_remove_disk();
    rcu_assign_pointer(conf->rdev, NULL);
    synchronize_rcu();
   mddev_unlock()

   // triggered by daemon
   mddev_lock()
   rdev_removeable();
   synchronize_rcu(); -> this can't protect accessing rdev from conf
   pers->hot_remove_disk();
    rcu_assign_pointer(conf->rdev, NULL);
   mddev_unlock()

6. md_kick_rdev_from_array() remove rdev from mddev->disks;

   mddev_lock()
   list_del_rcu(&rdev->same_set);
   synchronize_rcu();
   list_add(&rdev->same_set, &mddev->deleting)
   mddev_unlock()
    export_rdev

There are two separate rcu protection for rdev, and this pathset remove
the protection of conf(step 3 and 5), because it's safe to access rdev
from conf in following cases:

 - If 'reconfig_mutex' is held, because rdev can't be added or rmoved to
 conf;
 - If there is normal IO inflight, because mddev_suspend() will wait for
 IO to be done and prevent rdev to be added or removed to conf;
 - If sync thread is running, because remove_and_add_spares() can only be
 called from daemon thread when sync thread is done, and
 'MD_RECOVERY_RUNNING' is also checked for ioctl/sysfs;
 - if any spinlock or rcu_read_lock() is held, because synchronize_rcu()
 from step 6 prevent rdev to be freed until spinlock is released or
 rcu_read_unlock();
This commit is contained in:
Song Liu 2023-11-27 15:49:57 -08:00
commit 726a9b67e9
9 changed files with 168 additions and 421 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
drivers/md/md-multipath.c
View File

@ -32,17 +32,15 @@ static int multipath_map (struct mpconf *conf)
* now we use the first available disk.
*/
rcu_read_lock();
for (i = 0; i < disks; i++) {
struct md_rdev *rdev = rcu_dereference(conf->multipaths[i].rdev);
struct md_rdev *rdev = conf->multipaths[i].rdev;
if (rdev && test_bit(In_sync, &rdev->flags) &&
!test_bit(Faulty, &rdev->flags)) {
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
return i;
}
}
rcu_read_unlock();
pr_crit_ratelimited("multipath_map(): no more operational IO paths?\n");
return (-1);
@ -137,14 +135,16 @@ static void multipath_status(struct seq_file *seq, struct mddev *mddev)
struct mpconf *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->multipaths[i].rdev);
seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
struct md_rdev *rdev = READ_ONCE(conf->multipaths[i].rdev);
seq_printf(seq, "%s",
rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
}
rcu_read_unlock();
seq_putc(seq, ']');
}
@ -182,7 +182,7 @@ static void multipath_error (struct mddev *mddev, struct md_rdev *rdev)
conf->raid_disks - mddev->degraded);
}
static void print_multipath_conf (struct mpconf *conf)
static void print_multipath_conf(struct mpconf *conf)
{
int i;
struct multipath_info *tmp;
@ -195,6 +195,7 @@ static void print_multipath_conf (struct mpconf *conf)
pr_debug(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
conf->raid_disks);
lockdep_assert_held(&conf->mddev->reconfig_mutex);
for (i = 0; i < conf->raid_disks; i++) {
tmp = conf->multipaths + i;
if (tmp->rdev)
@ -231,7 +232,7 @@ static int multipath_add_disk(struct mddev *mddev, struct md_rdev *rdev)
rdev->raid_disk = path;
set_bit(In_sync, &rdev->flags);
spin_unlock_irq(&conf->device_lock);
rcu_assign_pointer(p->rdev, rdev);
WRITE_ONCE(p->rdev, rdev);
err = 0;
break;
}
@ -257,16 +258,7 @@ static int multipath_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
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;
}
}
WRITE_ONCE(p->rdev, NULL);
err = md_integrity_register(mddev);
}
abort:

37
drivers/md/md.c
View File

@ -9244,46 +9244,21 @@ static int remove_and_add_spares(struct mddev *mddev,
struct md_rdev *rdev;
int spares = 0;
int removed = 0;
bool remove_some = false;
if (this && test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
/* Mustn't remove devices when resync thread is running */
return 0;
rdev_for_each(rdev, mddev) {
if ((this == NULL || rdev == this) &&
rdev->raid_disk >= 0 &&
!test_bit(Blocked, &rdev->flags) &&
test_bit(Faulty, &rdev->flags) &&
atomic_read(&rdev->nr_pending)==0) {
/* Faulty non-Blocked devices with nr_pending == 0
* never get nr_pending incremented,
* never get Faulty cleared, and never get Blocked set.
* So we can synchronize_rcu now rather than once per device
*/
remove_some = true;
set_bit(RemoveSynchronized, &rdev->flags);
if ((this == NULL || rdev == this) && rdev_removeable(rdev) &&
!mddev->pers->hot_remove_disk(mddev, rdev)) {
sysfs_unlink_rdev(mddev, rdev);
rdev->saved_raid_disk = rdev->raid_disk;
rdev->raid_disk = -1;
removed++;
}
}
if (remove_some)
synchronize_rcu();
rdev_for_each(rdev, mddev) {
if ((this == NULL || rdev == this) &&
(test_bit(RemoveSynchronized, &rdev->flags) ||
rdev_removeable(rdev))) {
if (mddev->pers->hot_remove_disk(
mddev, rdev) == 0) {
sysfs_unlink_rdev(mddev, rdev);
rdev->saved_raid_disk = rdev->raid_disk;
rdev->raid_disk = -1;
removed++;
}
}
if (remove_some && test_bit(RemoveSynchronized, &rdev->flags))
clear_bit(RemoveSynchronized, &rdev->flags);
}
if (removed && mddev->kobj.sd)
sysfs_notify_dirent_safe(mddev->sysfs_degraded);

5
drivers/md/md.h
View File

@ -190,11 +190,6 @@ enum flag_bits {
* than other devices in the array
*/
ClusterRemove,
RemoveSynchronized, /* synchronize_rcu() was called after
* this device was known to be faulty,
* so it is safe to remove without
* another synchronize_rcu() call.
*/
ExternalBbl, /* External metadata provides bad
* block management for a disk
*/

71
drivers/md/raid1.c
View File

@ -609,7 +609,6 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
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.
@ -642,7 +641,7 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
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))
@ -773,7 +772,7 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
}
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 +783,6 @@ 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 +1233,12 @@ 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 +1392,9 @@ 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 +1460,6 @@ 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 +1611,16 @@ 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 +1686,15 @@ 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)
@ -1810,7 +1804,7 @@ static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
*/
if (rdev->saved_raid_disk < 0)
conf->fullsync = 1;
rcu_assign_pointer(p->rdev, rdev);
WRITE_ONCE(p->rdev, rdev);
break;
}
if (test_bit(WantReplacement, &p->rdev->flags) &&
@ -1826,7 +1820,7 @@ static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
rdev->raid_disk = repl_slot;
err = 0;
conf->fullsync = 1;
rcu_assign_pointer(p[conf->raid_disks].rdev, rdev);
WRITE_ONCE(p[conf->raid_disks].rdev, rdev);
}
print_conf(conf);
@ -1862,16 +1856,7 @@ static int raid1_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
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;
}
}
WRITE_ONCE(p->rdev, NULL);
if (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
@ -1892,7 +1877,7 @@ 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 +2275,7 @@ 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 +2283,14 @@ 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 +2309,24 @@ 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, 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, READ)) {
atomic_add(s, &rdev->corrected_errors);
@ -2359,8 +2337,7 @@ 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 +2718,6 @@ 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 +2738,7 @@ 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 +2796,6 @@ 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;

222
drivers/md/raid10.c
View File

@ -743,7 +743,6 @@ static struct md_rdev *read_balance(struct r10conf *conf,
struct geom *geo = &conf->geo;
raid10_find_phys(conf, r10_bio);
rcu_read_lock();
best_dist_slot = -1;
min_pending = UINT_MAX;
best_dist_rdev = NULL;
@ -775,18 +774,11 @@ static struct md_rdev *read_balance(struct r10conf *conf,
if (r10_bio->devs[slot].bio == IO_BLOCKED)
continue;
disk = r10_bio->devs[slot].devnum;
rdev = rcu_dereference(conf->mirrors[disk].replacement);
rdev = conf->mirrors[disk].replacement;
if (rdev == NULL || test_bit(Faulty, &rdev->flags) ||
r10_bio->devs[slot].addr + sectors >
rdev->recovery_offset) {
/*
* Read replacement first to prevent reading both rdev
* and replacement as NULL during replacement replace
* rdev.
*/
smp_mb();
rdev = rcu_dereference(conf->mirrors[disk].rdev);
}
rdev->recovery_offset)
rdev = conf->mirrors[disk].rdev;
if (rdev == NULL ||
test_bit(Faulty, &rdev->flags))
continue;
@ -876,7 +868,6 @@ static struct md_rdev *read_balance(struct r10conf *conf,
r10_bio->read_slot = slot;
} else
rdev = NULL;
rcu_read_unlock();
*max_sectors = best_good_sectors;
return rdev;
@ -1198,9 +1189,8 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
*/
gfp = GFP_NOIO | __GFP_HIGH;
rcu_read_lock();
disk = r10_bio->devs[slot].devnum;
err_rdev = rcu_dereference(conf->mirrors[disk].rdev);
err_rdev = conf->mirrors[disk].rdev;
if (err_rdev)
snprintf(b, sizeof(b), "%pg", err_rdev->bdev);
else {
@ -1208,7 +1198,6 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
/* This never gets dereferenced */
err_rdev = r10_bio->devs[slot].rdev;
}
rcu_read_unlock();
}
if (!regular_request_wait(mddev, conf, bio, r10_bio->sectors))
@ -1279,15 +1268,8 @@ static void raid10_write_one_disk(struct mddev *mddev, struct r10bio *r10_bio,
int devnum = r10_bio->devs[n_copy].devnum;
struct bio *mbio;
if (replacement) {
rdev = conf->mirrors[devnum].replacement;
if (rdev == NULL) {
/* Replacement just got moved to main 'rdev' */
smp_mb();
rdev = conf->mirrors[devnum].rdev;
}
} else
rdev = conf->mirrors[devnum].rdev;
rdev = replacement ? conf->mirrors[devnum].replacement :
conf->mirrors[devnum].rdev;
mbio = bio_alloc_clone(rdev->bdev, bio, GFP_NOIO, &mddev->bio_set);
if (replacement)
@ -1321,25 +1303,6 @@ static void raid10_write_one_disk(struct mddev *mddev, struct r10bio *r10_bio,
}
}
static struct md_rdev *dereference_rdev_and_rrdev(struct raid10_info *mirror,
struct md_rdev **prrdev)
{
struct md_rdev *rdev, *rrdev;
rrdev = rcu_dereference(mirror->replacement);
/*
* Read replacement first to prevent reading both rdev and
* replacement as NULL during replacement replace rdev.
*/
smp_mb();
rdev = rcu_dereference(mirror->rdev);
if (rdev == rrdev)
rrdev = NULL;
*prrdev = rrdev;
return rdev;
}
static void wait_blocked_dev(struct mddev *mddev, struct r10bio *r10_bio)
{
int i;
@ -1348,11 +1311,11 @@ static void wait_blocked_dev(struct mddev *mddev, struct r10bio *r10_bio)
retry_wait:
blocked_rdev = NULL;
rcu_read_lock();
for (i = 0; i < conf->copies; i++) {
struct md_rdev *rdev, *rrdev;
rdev = dereference_rdev_and_rrdev(&conf->mirrors[i], &rrdev);
rdev = conf->mirrors[i].rdev;
rrdev = conf->mirrors[i].replacement;
if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
atomic_inc(&rdev->nr_pending);
blocked_rdev = rdev;
@ -1391,7 +1354,6 @@ retry_wait:
}
}
}
rcu_read_unlock();
if (unlikely(blocked_rdev)) {
/* Have to wait for this device to get unblocked, then retry */
@ -1474,14 +1436,14 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio,
wait_blocked_dev(mddev, r10_bio);
rcu_read_lock();
max_sectors = r10_bio->sectors;
for (i = 0; i < conf->copies; i++) {
int d = r10_bio->devs[i].devnum;
struct md_rdev *rdev, *rrdev;
rdev = dereference_rdev_and_rrdev(&conf->mirrors[d], &rrdev);
rdev = conf->mirrors[d].rdev;
rrdev = conf->mirrors[d].replacement;
if (rdev && (test_bit(Faulty, &rdev->flags)))
rdev = NULL;
if (rrdev && (test_bit(Faulty, &rrdev->flags)))
@ -1535,7 +1497,6 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio,
atomic_inc(&rrdev->nr_pending);
}
}
rcu_read_unlock();
if (max_sectors < r10_bio->sectors)
r10_bio->sectors = max_sectors;
@ -1625,17 +1586,8 @@ static void raid10_end_discard_request(struct bio *bio)
set_bit(R10BIO_Uptodate, &r10_bio->state);
dev = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
if (repl)
rdev = conf->mirrors[dev].replacement;
if (!rdev) {
/*
* raid10_remove_disk uses smp_mb to make sure rdev is set to
* replacement before setting replacement to NULL. It can read
* rdev first without barrier protect even replacement is NULL
*/
smp_rmb();
rdev = conf->mirrors[dev].rdev;
}
rdev = repl ? conf->mirrors[dev].replacement :
conf->mirrors[dev].rdev;
raid_end_discard_bio(r10_bio);
rdev_dec_pending(rdev, conf->mddev);
@ -1785,11 +1737,11 @@ retry_discard:
* inc refcount on their rdev. Record them by setting
* bios[x] to bio
*/
rcu_read_lock();
for (disk = 0; disk < geo->raid_disks; disk++) {
struct md_rdev *rdev, *rrdev;
rdev = dereference_rdev_and_rrdev(&conf->mirrors[disk], &rrdev);
rdev = conf->mirrors[disk].rdev;
rrdev = conf->mirrors[disk].replacement;
r10_bio->devs[disk].bio = NULL;
r10_bio->devs[disk].repl_bio = NULL;
@ -1809,7 +1761,6 @@ retry_discard:
atomic_inc(&rrdev->nr_pending);
}
}
rcu_read_unlock();
atomic_set(&r10_bio->remaining, 1);
for (disk = 0; disk < geo->raid_disks; disk++) {
@ -1939,6 +1890,8 @@ static void raid10_status(struct seq_file *seq, struct mddev *mddev)
struct r10conf *conf = mddev->private;
int i;
lockdep_assert_held(&mddev->lock);
if (conf->geo.near_copies < conf->geo.raid_disks)
seq_printf(seq, " %dK chunks", mddev->chunk_sectors / 2);
if (conf->geo.near_copies > 1)
@ -1953,12 +1906,11 @@ static void raid10_status(struct seq_file *seq, struct mddev *mddev)
}
seq_printf(seq, " [%d/%d] [", conf->geo.raid_disks,
conf->geo.raid_disks - mddev->degraded);
rcu_read_lock();
for (i = 0; i < conf->geo.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, "]");
}
@ -1980,7 +1932,6 @@ static int _enough(struct r10conf *conf, int previous, int ignore)
ncopies = conf->geo.near_copies;
}
rcu_read_lock();
do {
int n = conf->copies;
int cnt = 0;
@ -1988,7 +1939,7 @@ static int _enough(struct r10conf *conf, int previous, int ignore)
while (n--) {
struct md_rdev *rdev;
if (this != ignore &&
(rdev = rcu_dereference(conf->mirrors[this].rdev)) &&
(rdev = conf->mirrors[this].rdev) &&
test_bit(In_sync, &rdev->flags))
cnt++;
this = (this+1) % disks;
@ -1999,7 +1950,6 @@ static int _enough(struct r10conf *conf, int previous, int ignore)
} while (first != 0);
has_enough = 1;
out:
rcu_read_unlock();
return has_enough;
}
@ -2072,8 +2022,7 @@ static void print_conf(struct r10conf *conf)
pr_debug(" --- wd:%d rd:%d\n", conf->geo.raid_disks - conf->mddev->degraded,
conf->geo.raid_disks);
/* This is only called with ->reconfix_mutex held, so
* rcu protection of rdev is not needed */
lockdep_assert_held(&conf->mddev->reconfig_mutex);
for (i = 0; i < conf->geo.raid_disks; i++) {
rdev = conf->mirrors[i].rdev;
if (rdev)
@ -2190,7 +2139,7 @@ static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
err = 0;
if (rdev->saved_raid_disk != mirror)
conf->fullsync = 1;
rcu_assign_pointer(p->rdev, rdev);
WRITE_ONCE(p->rdev, rdev);
break;
}
@ -2204,7 +2153,7 @@ static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
disk_stack_limits(mddev->gendisk, rdev->bdev,
rdev->data_offset << 9);
conf->fullsync = 1;
rcu_assign_pointer(p->replacement, rdev);
WRITE_ONCE(p->replacement, rdev);
}
print_conf(conf);
@ -2246,24 +2195,12 @@ static int raid10_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
err = -EBUSY;
goto abort;
}
*rdevp = NULL;
if (!test_bit(RemoveSynchronized, &rdev->flags)) {
synchronize_rcu();
if (atomic_read(&rdev->nr_pending)) {
/* lost the race, try later */
err = -EBUSY;
*rdevp = rdev;
goto abort;
}
}
WRITE_ONCE(*rdevp, NULL);
if (p->replacement) {
/* We must have just cleared 'rdev' */
p->rdev = p->replacement;
WRITE_ONCE(p->rdev, p->replacement);
clear_bit(Replacement, &p->replacement->flags);
smp_mb(); /* Make sure other CPUs may see both as identical
* but will never see neither -- if they are careful.
*/
p->replacement = NULL;
WRITE_ONCE(p->replacement, NULL);
}
clear_bit(WantReplacement, &rdev->flags);
@ -2763,20 +2700,18 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
if (s > (PAGE_SIZE>>9))
s = PAGE_SIZE >> 9;
rcu_read_lock();
do {
sector_t first_bad;
int bad_sectors;
d = r10_bio->devs[sl].devnum;
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) &&
is_badblock(rdev, r10_bio->devs[sl].addr + sect, s,
&first_bad, &bad_sectors) == 0) {
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
success = sync_page_io(rdev,
r10_bio->devs[sl].addr +
sect,
@ -2784,7 +2719,6 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
conf->tmppage,
REQ_OP_READ, false);
rdev_dec_pending(rdev, mddev);
rcu_read_lock();
if (success)
break;
}
@ -2792,7 +2726,6 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
if (sl == conf->copies)
sl = 0;
} while (sl != slot);
rcu_read_unlock();
if (!success) {
/* Cannot read from anywhere, just mark the block
@ -2816,20 +2749,18 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
start = sl;
/* write it back and re-read */
rcu_read_lock();
while (sl != slot) {
if (sl==0)
sl = conf->copies;
sl--;
d = r10_bio->devs[sl].devnum;
rdev = rcu_dereference(conf->mirrors[d].rdev);
rdev = conf->mirrors[d].rdev;
if (!rdev ||
test_bit(Faulty, &rdev->flags) ||
!test_bit(In_sync, &rdev->flags))
continue;
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
if (r10_sync_page_io(rdev,
r10_bio->devs[sl].addr +
sect,
@ -2848,7 +2779,6 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
rdev->bdev);
}
rdev_dec_pending(rdev, mddev);
rcu_read_lock();
}
sl = start;
while (sl != slot) {
@ -2856,14 +2786,13 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
sl = conf->copies;
sl--;
d = r10_bio->devs[sl].devnum;
rdev = rcu_dereference(conf->mirrors[d].rdev);
rdev = conf->mirrors[d].rdev;
if (!rdev ||
test_bit(Faulty, &rdev->flags) ||
!test_bit(In_sync, &rdev->flags))
continue;
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
switch (r10_sync_page_io(rdev,
r10_bio->devs[sl].addr +
sect,
@ -2891,9 +2820,7 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
}
rdev_dec_pending(rdev, mddev);
rcu_read_lock();
}
rcu_read_unlock();
sectors -= s;
sect += s;
@ -3367,14 +3294,13 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
/* Completed a full sync so the replacements
* are now fully recovered.
*/
rcu_read_lock();
for (i = 0; i < conf->geo.raid_disks; i++) {
struct md_rdev *rdev =
rcu_dereference(conf->mirrors[i].replacement);
conf->mirrors[i].replacement;
if (rdev)
rdev->recovery_offset = MaxSector;
}
rcu_read_unlock();
}
conf->fullsync = 0;
}
@ -3455,9 +3381,8 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
struct raid10_info *mirror = &conf->mirrors[i];
struct md_rdev *mrdev, *mreplace;
rcu_read_lock();
mrdev = rcu_dereference(mirror->rdev);
mreplace = rcu_dereference(mirror->replacement);
mrdev = mirror->rdev;
mreplace = mirror->replacement;
if (mrdev && (test_bit(Faulty, &mrdev->flags) ||
test_bit(In_sync, &mrdev->flags)))
@ -3465,22 +3390,18 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
if (mreplace && test_bit(Faulty, &mreplace->flags))
mreplace = NULL;
if (!mrdev && !mreplace) {
rcu_read_unlock();
if (!mrdev && !mreplace)
continue;
}
still_degraded = 0;
/* want to reconstruct this device */
rb2 = r10_bio;
sect = raid10_find_virt(conf, sector_nr, i);
if (sect >= mddev->resync_max_sectors) {
if (sect >= mddev->resync_max_sectors)
/* last stripe is not complete - don't
* try to recover this sector.
*/
rcu_read_unlock();
continue;
}
/* Unless we are doing a full sync, or a replacement
* we only need to recover the block if it is set in
* the bitmap
@ -3496,14 +3417,12 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
* that there will never be anything to do here
*/
chunks_skipped = -1;
rcu_read_unlock();
continue;
}
if (mrdev)
atomic_inc(&mrdev->nr_pending);
if (mreplace)
atomic_inc(&mreplace->nr_pending);
rcu_read_unlock();
r10_bio = raid10_alloc_init_r10buf(conf);
r10_bio->state = 0;
@ -3522,10 +3441,9 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
/* Need to check if the array will still be
* degraded
*/
rcu_read_lock();
for (j = 0; j < conf->geo.raid_disks; j++) {
struct md_rdev *rdev = rcu_dereference(
conf->mirrors[j].rdev);
struct md_rdev *rdev = conf->mirrors[j].rdev;
if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
still_degraded = 1;
break;
@ -3540,8 +3458,7 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
int k;
int d = r10_bio->devs[j].devnum;
sector_t from_addr, to_addr;
struct md_rdev *rdev =
rcu_dereference(conf->mirrors[d].rdev);
struct md_rdev *rdev = conf->mirrors[d].rdev;
sector_t sector, first_bad;
int bad_sectors;
if (!rdev ||
@ -3620,7 +3537,6 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
atomic_inc(&r10_bio->remaining);
break;
}
rcu_read_unlock();
if (j == conf->copies) {
/* Cannot recover, so abort the recovery or
* record a bad block */
@ -3747,12 +3663,10 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
bio = r10_bio->devs[i].bio;
bio->bi_status = BLK_STS_IOERR;
rcu_read_lock();
rdev = rcu_dereference(conf->mirrors[d].rdev);
if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
rcu_read_unlock();
rdev = conf->mirrors[d].rdev;
if (rdev == NULL || test_bit(Faulty, &rdev->flags))
continue;
}
sector = r10_bio->devs[i].addr;
if (is_badblock(rdev, sector, max_sync,
&first_bad, &bad_sectors)) {
@ -3762,7 +3676,6 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
bad_sectors -= (sector - first_bad);
if (max_sync > bad_sectors)
max_sync = bad_sectors;
rcu_read_unlock();
continue;
}
}
@ -3778,11 +3691,10 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
bio_set_dev(bio, rdev->bdev);
count++;
rdev = rcu_dereference(conf->mirrors[d].replacement);
if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
rcu_read_unlock();
rdev = conf->mirrors[d].replacement;
if (rdev == NULL || test_bit(Faulty, &rdev->flags))
continue;
}
atomic_inc(&rdev->nr_pending);
/* Need to set up for writing to the replacement */
@ -3799,7 +3711,6 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
bio->bi_iter.bi_sector = sector + rdev->data_offset;
bio_set_dev(bio, rdev->bdev);
count++;
rcu_read_unlock();
}
if (count < 2) {
@ -4509,11 +4420,11 @@ static int calc_degraded(struct r10conf *conf)
int degraded, degraded2;
int i;
rcu_read_lock();
degraded = 0;
/* 'prev' section first */
for (i = 0; i < conf->prev.raid_disks; i++) {
struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
struct md_rdev *rdev = conf->mirrors[i].rdev;
if (!rdev || test_bit(Faulty, &rdev->flags))
degraded++;
else if (!test_bit(In_sync, &rdev->flags))
@ -4523,13 +4434,12 @@ static int calc_degraded(struct r10conf *conf)
*/
degraded++;
}
rcu_read_unlock();
if (conf->geo.raid_disks == conf->prev.raid_disks)
return degraded;
rcu_read_lock();
degraded2 = 0;
for (i = 0; i < conf->geo.raid_disks; i++) {
struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
struct md_rdev *rdev = conf->mirrors[i].rdev;
if (!rdev || test_bit(Faulty, &rdev->flags))
degraded2++;
else if (!test_bit(In_sync, &rdev->flags)) {
@ -4542,7 +4452,6 @@ static int calc_degraded(struct r10conf *conf)
degraded2++;
}
}
rcu_read_unlock();
if (degraded2 > degraded)
return degraded2;
return degraded;
@ -4974,16 +4883,15 @@ read_more:
blist = read_bio;
read_bio->bi_next = NULL;
rcu_read_lock();
for (s = 0; s < conf->copies*2; s++) {
struct bio *b;
int d = r10_bio->devs[s/2].devnum;
struct md_rdev *rdev2;
if (s&1) {
rdev2 = rcu_dereference(conf->mirrors[d].replacement);
rdev2 = conf->mirrors[d].replacement;
b = r10_bio->devs[s/2].repl_bio;
} else {
rdev2 = rcu_dereference(conf->mirrors[d].rdev);
rdev2 = conf->mirrors[d].rdev;
b = r10_bio->devs[s/2].bio;
}
if (!rdev2 || test_bit(Faulty, &rdev2->flags))
@ -5017,7 +4925,6 @@ read_more:
sector_nr += len >> 9;
nr_sectors += len >> 9;
}
rcu_read_unlock();
r10_bio->sectors = nr_sectors;
/* Now submit the read */
@ -5070,20 +4977,17 @@ static void reshape_request_write(struct mddev *mddev, struct r10bio *r10_bio)
struct bio *b;
int d = r10_bio->devs[s/2].devnum;
struct md_rdev *rdev;
rcu_read_lock();
if (s&1) {
rdev = rcu_dereference(conf->mirrors[d].replacement);
rdev = conf->mirrors[d].replacement;
b = r10_bio->devs[s/2].repl_bio;
} else {
rdev = rcu_dereference(conf->mirrors[d].rdev);
rdev = conf->mirrors[d].rdev;
b = r10_bio->devs[s/2].bio;
}
if (!rdev || test_bit(Faulty, &rdev->flags)) {
rcu_read_unlock();
if (!rdev || test_bit(Faulty, &rdev->flags))
continue;
}
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
md_sync_acct_bio(b, r10_bio->sectors);
atomic_inc(&r10_bio->remaining);
b->bi_next = NULL;
@ -5154,10 +5058,9 @@ static int handle_reshape_read_error(struct mddev *mddev,
if (s > (PAGE_SIZE >> 9))
s = PAGE_SIZE >> 9;
rcu_read_lock();
while (!success) {
int d = r10b->devs[slot].devnum;
struct md_rdev *rdev = rcu_dereference(conf->mirrors[d].rdev);
struct md_rdev *rdev = conf->mirrors[d].rdev;
sector_t addr;
if (rdev == NULL ||
test_bit(Faulty, &rdev->flags) ||
@ -5166,14 +5069,12 @@ static int handle_reshape_read_error(struct mddev *mddev,
addr = r10b->devs[slot].addr + idx * PAGE_SIZE;
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
success = sync_page_io(rdev,
addr,
s << 9,
pages[idx],
REQ_OP_READ, false);
rdev_dec_pending(rdev, mddev);
rcu_read_lock();
if (success)
break;
failed:
@ -5183,7 +5084,6 @@ static int handle_reshape_read_error(struct mddev *mddev,
if (slot == first_slot)
break;
}
rcu_read_unlock();
if (!success) {
/* couldn't read this block, must give up */
set_bit(MD_RECOVERY_INTR,
@ -5209,12 +5109,8 @@ static void end_reshape_write(struct bio *bio)
struct md_rdev *rdev = NULL;
d = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
if (repl)
rdev = conf->mirrors[d].replacement;
if (!rdev) {
smp_mb();
rdev = conf->mirrors[d].rdev;
}
rdev = repl ? conf->mirrors[d].replacement :
conf->mirrors[d].rdev;
if (bio->bi_status) {
/* FIXME should record badblock */
@ -5249,18 +5145,16 @@ static void raid10_finish_reshape(struct mddev *mddev)
mddev->resync_max_sectors = mddev->array_sectors;
} else {
int d;
rcu_read_lock();
for (d = conf->geo.raid_disks ;
d < conf->geo.raid_disks - mddev->delta_disks;
d++) {
struct md_rdev *rdev = rcu_dereference(conf->mirrors[d].rdev);
struct md_rdev *rdev = conf->mirrors[d].rdev;
if (rdev)
clear_bit(In_sync, &rdev->flags);
rdev = rcu_dereference(conf->mirrors[d].replacement);
rdev = conf->mirrors[d].replacement;
if (rdev)
clear_bit(In_sync, &rdev->flags);
}
rcu_read_unlock();
}
mddev->layout = mddev->new_layout;
mddev->chunk_sectors = 1 << conf->geo.chunk_shift;

11
drivers/md/raid5-cache.c
View File

@ -1890,28 +1890,22 @@ r5l_recovery_replay_one_stripe(struct r5conf *conf,
continue;
/* in case device is broken */
rcu_read_lock();
rdev = rcu_dereference(conf->disks[disk_index].rdev);
rdev = conf->disks[disk_index].rdev;
if (rdev) {
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
sync_page_io(rdev, sh->sector, PAGE_SIZE,
sh->dev[disk_index].page, REQ_OP_WRITE,
false);
rdev_dec_pending(rdev, rdev->mddev);
rcu_read_lock();
}
rrdev = rcu_dereference(conf->disks[disk_index].replacement);
rrdev = conf->disks[disk_index].replacement;
if (rrdev) {
atomic_inc(&rrdev->nr_pending);
rcu_read_unlock();
sync_page_io(rrdev, sh->sector, PAGE_SIZE,
sh->dev[disk_index].page, REQ_OP_WRITE,
false);
rdev_dec_pending(rrdev, rrdev->mddev);
rcu_read_lock();
}
rcu_read_unlock();
}
ctx->data_parity_stripes++;
out:
@ -2948,7 +2942,6 @@ bool r5c_big_stripe_cached(struct r5conf *conf, sector_t sect)
if (!log)
return false;
WARN_ON_ONCE(!rcu_read_lock_held());
tree_index = r5c_tree_index(conf, sect);
slot = radix_tree_lookup(&log->big_stripe_tree, tree_index);
return slot != NULL;

16
drivers/md/raid5-ppl.c
View File

@ -620,11 +620,9 @@ static void ppl_do_flush(struct ppl_io_unit *io)
struct md_rdev *rdev;
struct block_device *bdev = NULL;
rcu_read_lock();
rdev = rcu_dereference(conf->disks[i].rdev);
rdev = conf->disks[i].rdev;
if (rdev && !test_bit(Faulty, &rdev->flags))
bdev = rdev->bdev;
rcu_read_unlock();
if (bdev) {
struct bio *bio;
@ -882,9 +880,7 @@ static int ppl_recover_entry(struct ppl_log *log, struct ppl_header_entry *e,
(unsigned long long)r_sector, dd_idx,
(unsigned long long)sector);
/* Array has not started so rcu dereference is safe */
rdev = rcu_dereference_protected(
conf->disks[dd_idx].rdev, 1);
rdev = conf->disks[dd_idx].rdev;
if (!rdev || (!test_bit(In_sync, &rdev->flags) &&
sector >= rdev->recovery_offset)) {
pr_debug("%s:%*s data member disk %d missing\n",
@ -936,9 +932,7 @@ static int ppl_recover_entry(struct ppl_log *log, struct ppl_header_entry *e,
0, &disk, &sh);
BUG_ON(sh.pd_idx != le32_to_cpu(e->parity_disk));
/* Array has not started so rcu dereference is safe */
parity_rdev = rcu_dereference_protected(
conf->disks[sh.pd_idx].rdev, 1);
parity_rdev = conf->disks[sh.pd_idx].rdev;
BUG_ON(parity_rdev->bdev->bd_dev != log->rdev->bdev->bd_dev);
pr_debug("%s:%*s write parity at sector %llu, disk %pg\n",
@ -1404,9 +1398,7 @@ int ppl_init_log(struct r5conf *conf)
for (i = 0; i < ppl_conf->count; i++) {
struct ppl_log *log = &ppl_conf->child_logs[i];
/* Array has not started so rcu dereference is safe */
struct md_rdev *rdev =
rcu_dereference_protected(conf->disks[i].rdev, 1);
struct md_rdev *rdev = conf->disks[i].rdev;
mutex_init(&log->io_mutex);
spin_lock_init(&log->io_list_lock);

191
drivers/md/raid5.c
View File

@ -693,12 +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))
@ -716,15 +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))
@ -738,7 +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;
@ -1183,14 +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;
@ -1211,7 +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
@ -2730,28 +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;
@ -2777,9 +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;
@ -2892,11 +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
@ -2904,7 +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;
}
}
@ -3666,15 +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,
@ -3792,16 +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)
@ -3809,7 +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;
@ -3822,15 +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;
}
@ -4707,7 +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;
@ -4752,7 +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),
@ -4763,7 +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))
@ -4810,8 +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)) {
@ -4823,8 +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);
@ -4832,8 +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);
@ -4854,8 +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;
}
@ -4882,7 +4845,6 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
else
s->replacing = 1;
}
rcu_read_unlock();
}
/*
@ -5339,23 +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);
@ -5514,24 +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)) {
@ -5575,10 +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)
@ -6581,14 +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);
@ -7899,18 +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");
@ -8094,15 +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, "]");
}
@ -8140,9 +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)
@ -8181,7 +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;
@ -8204,9 +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;
@ -8226,37 +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);
@ -8324,7 +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);
@ -8333,7 +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) {
@ -8342,7 +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;
}
}
@ -8475,7 +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) {
@ -8646,12 +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);
}

4
drivers/md/raid5.h
View File

@ -473,8 +473,8 @@ enum {
*/
struct disk_info {
struct md_rdev __rcu *rdev;
struct md_rdev __rcu *replacement;
struct md_rdev *rdev;
struct md_rdev *replacement;
struct page *extra_page; /* extra page to use in prexor */
};