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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.c205
1 files changed, 112 insertions, 93 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 04348d76bb30..259f519814ca 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -99,34 +99,40 @@ static inline struct bio *r5_next_bio(struct bio *bio, sector_t sector)
* We maintain a biased count of active stripes in the bottom 16 bits of
* bi_phys_segments, and a count of processed stripes in the upper 16 bits
*/
-static inline int raid5_bi_phys_segments(struct bio *bio)
+static inline int raid5_bi_processed_stripes(struct bio *bio)
{
- return bio->bi_phys_segments & 0xffff;
+ atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
+ return (atomic_read(segments) >> 16) & 0xffff;
}
-static inline int raid5_bi_hw_segments(struct bio *bio)
+static inline int raid5_dec_bi_active_stripes(struct bio *bio)
{
- return (bio->bi_phys_segments >> 16) & 0xffff;
+ atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
+ return atomic_sub_return(1, segments) & 0xffff;
}
-static inline int raid5_dec_bi_phys_segments(struct bio *bio)
+static inline void raid5_inc_bi_active_stripes(struct bio *bio)
{
- --bio->bi_phys_segments;
- return raid5_bi_phys_segments(bio);
+ atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
+ atomic_inc(segments);
}
-static inline int raid5_dec_bi_hw_segments(struct bio *bio)
+static inline void raid5_set_bi_processed_stripes(struct bio *bio,
+ unsigned int cnt)
{
- unsigned short val = raid5_bi_hw_segments(bio);
+ atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
+ int old, new;
- --val;
- bio->bi_phys_segments = (val << 16) | raid5_bi_phys_segments(bio);
- return val;
+ do {
+ old = atomic_read(segments);
+ new = (old & 0xffff) | (cnt << 16);
+ } while (atomic_cmpxchg(segments, old, new) != old);
}
-static inline void raid5_set_bi_hw_segments(struct bio *bio, unsigned int cnt)
+static inline void raid5_set_bi_stripes(struct bio *bio, unsigned int cnt)
{
- bio->bi_phys_segments = raid5_bi_phys_segments(bio) | (cnt << 16);
+ atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
+ atomic_set(segments, cnt);
}
/* Find first data disk in a raid6 stripe */
@@ -190,49 +196,56 @@ static int stripe_operations_active(struct stripe_head *sh)
test_bit(STRIPE_COMPUTE_RUN, &sh->state);
}
-static void __release_stripe(struct r5conf *conf, struct stripe_head *sh)
+static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh)
{
- if (atomic_dec_and_test(&sh->count)) {
- BUG_ON(!list_empty(&sh->lru));
- BUG_ON(atomic_read(&conf->active_stripes)==0);
- if (test_bit(STRIPE_HANDLE, &sh->state)) {
- if (test_bit(STRIPE_DELAYED, &sh->state) &&
- !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
- list_add_tail(&sh->lru, &conf->delayed_list);
- else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
- sh->bm_seq - conf->seq_write > 0)
- list_add_tail(&sh->lru, &conf->bitmap_list);
- else {
- clear_bit(STRIPE_DELAYED, &sh->state);
- clear_bit(STRIPE_BIT_DELAY, &sh->state);
- list_add_tail(&sh->lru, &conf->handle_list);
- }
- md_wakeup_thread(conf->mddev->thread);
- } else {
- BUG_ON(stripe_operations_active(sh));
- if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
- if (atomic_dec_return(&conf->preread_active_stripes)
- < IO_THRESHOLD)
- md_wakeup_thread(conf->mddev->thread);
- atomic_dec(&conf->active_stripes);
- if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
- list_add_tail(&sh->lru, &conf->inactive_list);
- wake_up(&conf->wait_for_stripe);
- if (conf->retry_read_aligned)
- md_wakeup_thread(conf->mddev->thread);
- }
+ BUG_ON(!list_empty(&sh->lru));
+ BUG_ON(atomic_read(&conf->active_stripes)==0);
+ if (test_bit(STRIPE_HANDLE, &sh->state)) {
+ if (test_bit(STRIPE_DELAYED, &sh->state) &&
+ !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+ list_add_tail(&sh->lru, &conf->delayed_list);
+ else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
+ sh->bm_seq - conf->seq_write > 0)
+ list_add_tail(&sh->lru, &conf->bitmap_list);
+ else {
+ clear_bit(STRIPE_DELAYED, &sh->state);
+ clear_bit(STRIPE_BIT_DELAY, &sh->state);
+ list_add_tail(&sh->lru, &conf->handle_list);
+ }
+ md_wakeup_thread(conf->mddev->thread);
+ } else {
+ BUG_ON(stripe_operations_active(sh));
+ if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+ if (atomic_dec_return(&conf->preread_active_stripes)
+ < IO_THRESHOLD)
+ md_wakeup_thread(conf->mddev->thread);
+ atomic_dec(&conf->active_stripes);
+ if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
+ list_add_tail(&sh->lru, &conf->inactive_list);
+ wake_up(&conf->wait_for_stripe);
+ if (conf->retry_read_aligned)
+ md_wakeup_thread(conf->mddev->thread);
}
}
}
+static void __release_stripe(struct r5conf *conf, struct stripe_head *sh)
+{
+ if (atomic_dec_and_test(&sh->count))
+ do_release_stripe(conf, sh);
+}
+
static void release_stripe(struct stripe_head *sh)
{
struct r5conf *conf = sh->raid_conf;
unsigned long flags;
- spin_lock_irqsave(&conf->device_lock, flags);
- __release_stripe(conf, sh);
- spin_unlock_irqrestore(&conf->device_lock, flags);
+ local_irq_save(flags);
+ if (atomic_dec_and_lock(&sh->count, &conf->device_lock)) {
+ do_release_stripe(conf, sh);
+ spin_unlock(&conf->device_lock);
+ }
+ local_irq_restore(flags);
}
static inline void remove_hash(struct stripe_head *sh)
@@ -640,6 +653,9 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
else
bi->bi_sector = (sh->sector
+ rdev->data_offset);
+ if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
+ bi->bi_rw |= REQ_FLUSH;
+
bi->bi_flags = 1 << BIO_UPTODATE;
bi->bi_idx = 0;
bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
@@ -749,14 +765,12 @@ static void ops_complete_biofill(void *stripe_head_ref)
{
struct stripe_head *sh = stripe_head_ref;
struct bio *return_bi = NULL;
- struct r5conf *conf = sh->raid_conf;
int i;
pr_debug("%s: stripe %llu\n", __func__,
(unsigned long long)sh->sector);
/* clear completed biofills */
- spin_lock_irq(&conf->device_lock);
for (i = sh->disks; i--; ) {
struct r5dev *dev = &sh->dev[i];
@@ -774,7 +788,7 @@ static void ops_complete_biofill(void *stripe_head_ref)
while (rbi && rbi->bi_sector <
dev->sector + STRIPE_SECTORS) {
rbi2 = r5_next_bio(rbi, dev->sector);
- if (!raid5_dec_bi_phys_segments(rbi)) {
+ if (!raid5_dec_bi_active_stripes(rbi)) {
rbi->bi_next = return_bi;
return_bi = rbi;
}
@@ -782,7 +796,6 @@ static void ops_complete_biofill(void *stripe_head_ref)
}
}
}
- spin_unlock_irq(&conf->device_lock);
clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
return_io(return_bi);
@@ -794,7 +807,6 @@ static void ops_complete_biofill(void *stripe_head_ref)
static void ops_run_biofill(struct stripe_head *sh)
{
struct dma_async_tx_descriptor *tx = NULL;
- struct r5conf *conf = sh->raid_conf;
struct async_submit_ctl submit;
int i;
@@ -805,10 +817,10 @@ static void ops_run_biofill(struct stripe_head *sh)
struct r5dev *dev = &sh->dev[i];
if (test_bit(R5_Wantfill, &dev->flags)) {
struct bio *rbi;
- spin_lock_irq(&conf->device_lock);
+ spin_lock_irq(&sh->stripe_lock);
dev->read = rbi = dev->toread;
dev->toread = NULL;
- spin_unlock_irq(&conf->device_lock);
+ spin_unlock_irq(&sh->stripe_lock);
while (rbi && rbi->bi_sector <
dev->sector + STRIPE_SECTORS) {
tx = async_copy_data(0, rbi, dev->page,
@@ -1144,12 +1156,12 @@ ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
if (test_and_clear_bit(R5_Wantdrain, &dev->flags)) {
struct bio *wbi;
- spin_lock_irq(&sh->raid_conf->device_lock);
+ spin_lock_irq(&sh->stripe_lock);
chosen = dev->towrite;
dev->towrite = NULL;
BUG_ON(dev->written);
wbi = dev->written = chosen;
- spin_unlock_irq(&sh->raid_conf->device_lock);
+ spin_unlock_irq(&sh->stripe_lock);
while (wbi && wbi->bi_sector <
dev->sector + STRIPE_SECTORS) {
@@ -1454,6 +1466,8 @@ static int grow_one_stripe(struct r5conf *conf)
init_waitqueue_head(&sh->ops.wait_for_ops);
#endif
+ spin_lock_init(&sh->stripe_lock);
+
if (grow_buffers(sh)) {
shrink_buffers(sh);
kmem_cache_free(conf->slab_cache, sh);
@@ -1739,7 +1753,9 @@ static void raid5_end_read_request(struct bio * bi, int error)
atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
clear_bit(R5_ReadError, &sh->dev[i].flags);
clear_bit(R5_ReWrite, &sh->dev[i].flags);
- }
+ } else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
+ clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
+
if (atomic_read(&rdev->read_errors))
atomic_set(&rdev->read_errors, 0);
} else {
@@ -1784,7 +1800,11 @@ static void raid5_end_read_request(struct bio * bi, int error)
else
retry = 1;
if (retry)
- set_bit(R5_ReadError, &sh->dev[i].flags);
+ if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
+ set_bit(R5_ReadError, &sh->dev[i].flags);
+ clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
+ } else
+ set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
else {
clear_bit(R5_ReadError, &sh->dev[i].flags);
clear_bit(R5_ReWrite, &sh->dev[i].flags);
@@ -2340,11 +2360,18 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, in
(unsigned long long)bi->bi_sector,
(unsigned long long)sh->sector);
-
- spin_lock_irq(&conf->device_lock);
+ /*
+ * If several bio share a stripe. The bio bi_phys_segments acts as a
+ * reference count to avoid race. The reference count should already be
+ * increased before this function is called (for example, in
+ * make_request()), so other bio sharing this stripe will not free the
+ * stripe. If a stripe is owned by one stripe, the stripe lock will
+ * protect it.
+ */
+ spin_lock_irq(&sh->stripe_lock);
if (forwrite) {
bip = &sh->dev[dd_idx].towrite;
- if (*bip == NULL && sh->dev[dd_idx].written == NULL)
+ if (*bip == NULL)
firstwrite = 1;
} else
bip = &sh->dev[dd_idx].toread;
@@ -2360,7 +2387,7 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, in
if (*bip)
bi->bi_next = *bip;
*bip = bi;
- bi->bi_phys_segments++;
+ raid5_inc_bi_active_stripes(bi);
if (forwrite) {
/* check if page is covered */
@@ -2375,7 +2402,7 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, in
if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
}
- spin_unlock_irq(&conf->device_lock);
+ spin_unlock_irq(&sh->stripe_lock);
pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
(unsigned long long)(*bip)->bi_sector,
@@ -2391,7 +2418,7 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, in
overlap:
set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
- spin_unlock_irq(&conf->device_lock);
+ spin_unlock_irq(&sh->stripe_lock);
return 0;
}
@@ -2441,10 +2468,11 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
rdev_dec_pending(rdev, conf->mddev);
}
}
- spin_lock_irq(&conf->device_lock);
+ spin_lock_irq(&sh->stripe_lock);
/* fail all writes first */
bi = sh->dev[i].towrite;
sh->dev[i].towrite = NULL;
+ spin_unlock_irq(&sh->stripe_lock);
if (bi) {
s->to_write--;
bitmap_end = 1;
@@ -2457,13 +2485,17 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
sh->dev[i].sector + STRIPE_SECTORS) {
struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
clear_bit(BIO_UPTODATE, &bi->bi_flags);
- if (!raid5_dec_bi_phys_segments(bi)) {
+ if (!raid5_dec_bi_active_stripes(bi)) {
md_write_end(conf->mddev);
bi->bi_next = *return_bi;
*return_bi = bi;
}
bi = nextbi;
}
+ if (bitmap_end)
+ bitmap_endwrite(conf->mddev->bitmap, sh->sector,
+ STRIPE_SECTORS, 0, 0);
+ bitmap_end = 0;
/* and fail all 'written' */
bi = sh->dev[i].written;
sh->dev[i].written = NULL;
@@ -2472,7 +2504,7 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
sh->dev[i].sector + STRIPE_SECTORS) {
struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
clear_bit(BIO_UPTODATE, &bi->bi_flags);
- if (!raid5_dec_bi_phys_segments(bi)) {
+ if (!raid5_dec_bi_active_stripes(bi)) {
md_write_end(conf->mddev);
bi->bi_next = *return_bi;
*return_bi = bi;
@@ -2496,14 +2528,13 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
struct bio *nextbi =
r5_next_bio(bi, sh->dev[i].sector);
clear_bit(BIO_UPTODATE, &bi->bi_flags);
- if (!raid5_dec_bi_phys_segments(bi)) {
+ if (!raid5_dec_bi_active_stripes(bi)) {
bi->bi_next = *return_bi;
*return_bi = bi;
}
bi = nextbi;
}
}
- spin_unlock_irq(&conf->device_lock);
if (bitmap_end)
bitmap_endwrite(conf->mddev->bitmap, sh->sector,
STRIPE_SECTORS, 0, 0);
@@ -2707,30 +2738,23 @@ static void handle_stripe_clean_event(struct r5conf *conf,
test_bit(R5_UPTODATE, &dev->flags)) {
/* We can return any write requests */
struct bio *wbi, *wbi2;
- int bitmap_end = 0;
pr_debug("Return write for disc %d\n", i);
- spin_lock_irq(&conf->device_lock);
wbi = dev->written;
dev->written = NULL;
while (wbi && wbi->bi_sector <
dev->sector + STRIPE_SECTORS) {
wbi2 = r5_next_bio(wbi, dev->sector);
- if (!raid5_dec_bi_phys_segments(wbi)) {
+ if (!raid5_dec_bi_active_stripes(wbi)) {
md_write_end(conf->mddev);
wbi->bi_next = *return_bi;
*return_bi = wbi;
}
wbi = wbi2;
}
- if (dev->towrite == NULL)
- bitmap_end = 1;
- spin_unlock_irq(&conf->device_lock);
- if (bitmap_end)
- bitmap_endwrite(conf->mddev->bitmap,
- sh->sector,
- STRIPE_SECTORS,
+ bitmap_endwrite(conf->mddev->bitmap, sh->sector,
+ STRIPE_SECTORS,
!test_bit(STRIPE_DEGRADED, &sh->state),
- 0);
+ 0);
}
}
@@ -3182,7 +3206,6 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
/* Now to look around and see what can be done */
rcu_read_lock();
- spin_lock_irq(&conf->device_lock);
for (i=disks; i--; ) {
struct md_rdev *rdev;
sector_t first_bad;
@@ -3328,7 +3351,6 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
do_recovery = 1;
}
}
- spin_unlock_irq(&conf->device_lock);
if (test_bit(STRIPE_SYNCING, &sh->state)) {
/* If there is a failed device being replaced,
* we must be recovering.
@@ -3791,7 +3813,7 @@ static struct bio *remove_bio_from_retry(struct r5conf *conf)
* this sets the active strip count to 1 and the processed
* strip count to zero (upper 8 bits)
*/
- bi->bi_phys_segments = 1; /* biased count of active stripes */
+ raid5_set_bi_stripes(bi, 1); /* biased count of active stripes */
}
return bi;
@@ -4113,7 +4135,7 @@ static void make_request(struct mddev *mddev, struct bio * bi)
finish_wait(&conf->wait_for_overlap, &w);
set_bit(STRIPE_HANDLE, &sh->state);
clear_bit(STRIPE_DELAYED, &sh->state);
- if ((bi->bi_rw & REQ_SYNC) &&
+ if ((bi->bi_rw & REQ_NOIDLE) &&
!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
atomic_inc(&conf->preread_active_stripes);
mddev_check_plugged(mddev);
@@ -4126,9 +4148,7 @@ static void make_request(struct mddev *mddev, struct bio * bi)
}
}
- spin_lock_irq(&conf->device_lock);
- remaining = raid5_dec_bi_phys_segments(bi);
- spin_unlock_irq(&conf->device_lock);
+ remaining = raid5_dec_bi_active_stripes(bi);
if (remaining == 0) {
if ( rw == WRITE )
@@ -4484,7 +4504,7 @@ static int retry_aligned_read(struct r5conf *conf, struct bio *raid_bio)
sector += STRIPE_SECTORS,
scnt++) {
- if (scnt < raid5_bi_hw_segments(raid_bio))
+ if (scnt < raid5_bi_processed_stripes(raid_bio))
/* already done this stripe */
continue;
@@ -4492,25 +4512,24 @@ static int retry_aligned_read(struct r5conf *conf, struct bio *raid_bio)
if (!sh) {
/* failed to get a stripe - must wait */
- raid5_set_bi_hw_segments(raid_bio, scnt);
+ raid5_set_bi_processed_stripes(raid_bio, scnt);
conf->retry_read_aligned = raid_bio;
return handled;
}
if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) {
release_stripe(sh);
- raid5_set_bi_hw_segments(raid_bio, scnt);
+ raid5_set_bi_processed_stripes(raid_bio, scnt);
conf->retry_read_aligned = raid_bio;
return handled;
}
+ set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
handle_stripe(sh);
release_stripe(sh);
handled++;
}
- spin_lock_irq(&conf->device_lock);
- remaining = raid5_dec_bi_phys_segments(raid_bio);
- spin_unlock_irq(&conf->device_lock);
+ remaining = raid5_dec_bi_active_stripes(raid_bio);
if (remaining == 0)
bio_endio(raid_bio, 0);
if (atomic_dec_and_test(&conf->active_aligned_reads))