1 files changed, 99 insertions, 37 deletions

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 55e7c56045a..ae16794bef2 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -101,6 +101,40 @@
 const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256)));
 #endif
 
+/*
+ * 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)
+{
+	return bio->bi_phys_segments & 0xffff;
+}
+
+static inline int raid5_bi_hw_segments(struct bio *bio)
+{
+	return (bio->bi_phys_segments >> 16) & 0xffff;
+}
+
+static inline int raid5_dec_bi_phys_segments(struct bio *bio)
+{
+	--bio->bi_phys_segments;
+	return raid5_bi_phys_segments(bio);
+}
+
+static inline int raid5_dec_bi_hw_segments(struct bio *bio)
+{
+	unsigned short val = raid5_bi_hw_segments(bio);
+
+	--val;
+	bio->bi_phys_segments = (val << 16) | raid5_bi_phys_segments(bio);
+	return val;
+}
+
+static inline void raid5_set_bi_hw_segments(struct bio *bio, unsigned int cnt)
+{
+	bio->bi_phys_segments = raid5_bi_phys_segments(bio) || (cnt << 16);
+}
+
 static inline int raid6_next_disk(int disk, int raid_disks)
 {
 	disk++;
@@ -507,7 +541,7 @@ 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 (--rbi->bi_phys_segments == 0) {
+				if (!raid5_dec_bi_phys_segments(rbi)) {
 					rbi->bi_next = return_bi;
 					return_bi = rbi;
 				}
@@ -1725,7 +1759,7 @@ 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 ++;
+	bi->bi_phys_segments++;
 	spin_unlock_irq(&conf->device_lock);
 	spin_unlock(&sh->lock);
 
@@ -1819,7 +1853,7 @@ handle_failed_stripe(raid5_conf_t *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 (--bi->bi_phys_segments == 0) {
+			if (!raid5_dec_bi_phys_segments(bi)) {
 				md_write_end(conf->mddev);
 				bi->bi_next = *return_bi;
 				*return_bi = bi;
@@ -1834,7 +1868,7 @@ handle_failed_stripe(raid5_conf_t *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 (--bi->bi_phys_segments == 0) {
+			if (!raid5_dec_bi_phys_segments(bi)) {
 				md_write_end(conf->mddev);
 				bi->bi_next = *return_bi;
 				*return_bi = bi;
@@ -1858,7 +1892,7 @@ handle_failed_stripe(raid5_conf_t *conf, struct stripe_head *sh,
 				struct bio *nextbi =
 					r5_next_bio(bi, sh->dev[i].sector);
 				clear_bit(BIO_UPTODATE, &bi->bi_flags);
-				if (--bi->bi_phys_segments == 0) {
+				if (!raid5_dec_bi_phys_segments(bi)) {
 					bi->bi_next = *return_bi;
 					*return_bi = bi;
 				}
@@ -2033,7 +2067,7 @@ static void handle_stripe_clean_event(raid5_conf_t *conf,
 				while (wbi && wbi->bi_sector <
 					dev->sector + STRIPE_SECTORS) {
 					wbi2 = r5_next_bio(wbi, dev->sector);
-					if (--wbi->bi_phys_segments == 0) {
+					if (!raid5_dec_bi_phys_segments(wbi)) {
 						md_write_end(conf->mddev);
 						wbi->bi_next = *return_bi;
 						*return_bi = wbi;
@@ -2507,7 +2541,7 @@ static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh,
  *
  */
 
-static void handle_stripe5(struct stripe_head *sh)
+static bool handle_stripe5(struct stripe_head *sh)
 {
 	raid5_conf_t *conf = sh->raid_conf;
 	int disks = sh->disks, i;
@@ -2568,10 +2602,10 @@ static void handle_stripe5(struct stripe_head *sh)
 		if (dev->written)
 			s.written++;
 		rdev = rcu_dereference(conf->disks[i].rdev);
-		if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
+		if (blocked_rdev == NULL &&
+		    rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
 			blocked_rdev = rdev;
 			atomic_inc(&rdev->nr_pending);
-			break;
 		}
 		if (!rdev || !test_bit(In_sync, &rdev->flags)) {
 			/* The ReadError flag will just be confusing now */
@@ -2588,8 +2622,14 @@ static void handle_stripe5(struct stripe_head *sh)
 	rcu_read_unlock();
 
 	if (unlikely(blocked_rdev)) {
-		set_bit(STRIPE_HANDLE, &sh->state);
-		goto unlock;
+		if (s.syncing || s.expanding || s.expanded ||
+		    s.to_write || s.written) {
+			set_bit(STRIPE_HANDLE, &sh->state);
+			goto unlock;
+		}
+		/* There is nothing for the blocked_rdev to block */
+		rdev_dec_pending(blocked_rdev, conf->mddev);
+		blocked_rdev = NULL;
 	}
 
 	if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
@@ -2717,10 +2757,11 @@ static void handle_stripe5(struct stripe_head *sh)
 	if (sh->reconstruct_state == reconstruct_state_result) {
 		sh->reconstruct_state = reconstruct_state_idle;
 		clear_bit(STRIPE_EXPANDING, &sh->state);
-		for (i = conf->raid_disks; i--; )
+		for (i = conf->raid_disks; i--; ) {
 			set_bit(R5_Wantwrite, &sh->dev[i].flags);
-			set_bit(R5_LOCKED, &dev->flags);
+			set_bit(R5_LOCKED, &sh->dev[i].flags);
 			s.locked++;
+		}
 	}
 
 	if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
@@ -2754,9 +2795,11 @@ static void handle_stripe5(struct stripe_head *sh)
 	ops_run_io(sh, &s);
 
 	return_io(return_bi);
+
+	return blocked_rdev == NULL;
 }
 
-static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
+static bool handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
 {
 	raid6_conf_t *conf = sh->raid_conf;
 	int disks = sh->disks;
@@ -2805,7 +2848,7 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
 				copy_data(0, rbi, dev->page, dev->sector);
 				rbi2 = r5_next_bio(rbi, dev->sector);
 				spin_lock_irq(&conf->device_lock);
-				if (--rbi->bi_phys_segments == 0) {
+				if (!raid5_dec_bi_phys_segments(rbi)) {
 					rbi->bi_next = return_bi;
 					return_bi = rbi;
 				}
@@ -2829,10 +2872,10 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
 		if (dev->written)
 			s.written++;
 		rdev = rcu_dereference(conf->disks[i].rdev);
-		if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
+		if (blocked_rdev == NULL &&
+		    rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
 			blocked_rdev = rdev;
 			atomic_inc(&rdev->nr_pending);
-			break;
 		}
 		if (!rdev || !test_bit(In_sync, &rdev->flags)) {
 			/* The ReadError flag will just be confusing now */
@@ -2850,9 +2893,16 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
 	rcu_read_unlock();
 
 	if (unlikely(blocked_rdev)) {
-		set_bit(STRIPE_HANDLE, &sh->state);
-		goto unlock;
+		if (s.syncing || s.expanding || s.expanded ||
+		    s.to_write || s.written) {
+			set_bit(STRIPE_HANDLE, &sh->state);
+			goto unlock;
+		}
+		/* There is nothing for the blocked_rdev to block */
+		rdev_dec_pending(blocked_rdev, conf->mddev);
+		blocked_rdev = NULL;
 	}
+
 	pr_debug("locked=%d uptodate=%d to_read=%d"
 	       " to_write=%d failed=%d failed_num=%d,%d\n",
 	       s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
@@ -2967,14 +3017,17 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
 	ops_run_io(sh, &s);
 
 	return_io(return_bi);
+
+	return blocked_rdev == NULL;
 }
 
-static void handle_stripe(struct stripe_head *sh, struct page *tmp_page)
+/* returns true if the stripe was handled */
+static bool handle_stripe(struct stripe_head *sh, struct page *tmp_page)
 {
 	if (sh->raid_conf->level == 6)
-		handle_stripe6(sh, tmp_page);
+		return handle_stripe6(sh, tmp_page);
 	else
-		handle_stripe5(sh);
+		return handle_stripe5(sh);
 }
 
 
@@ -3136,8 +3189,11 @@ static struct bio *remove_bio_from_retry(raid5_conf_t *conf)
 	if(bi) {
 		conf->retry_read_aligned_list = bi->bi_next;
 		bi->bi_next = NULL;
+		/*
+		 * 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 */
-		bi->bi_hw_segments = 0; /* count of processed stripes */
 	}
 
 	return bi;
@@ -3187,8 +3243,7 @@ static int bio_fits_rdev(struct bio *bi)
 	if ((bi->bi_size>>9) > q->max_sectors)
 		return 0;
 	blk_recount_segments(q, bi);
-	if (bi->bi_phys_segments > q->max_phys_segments ||
-	    bi->bi_hw_segments > q->max_hw_segments)
+	if (bi->bi_phys_segments > q->max_phys_segments)
 		return 0;
 
 	if (q->merge_bvec_fn)
@@ -3332,7 +3387,7 @@ static int make_request(struct request_queue *q, struct bio * bi)
 	sector_t logical_sector, last_sector;
 	struct stripe_head *sh;
 	const int rw = bio_data_dir(bi);
-	int remaining;
+	int cpu, remaining;
 
 	if (unlikely(bio_barrier(bi))) {
 		bio_endio(bi, -EOPNOTSUPP);
@@ -3341,8 +3396,11 @@ static int make_request(struct request_queue *q, struct bio * bi)
 
 	md_write_start(mddev, bi);
 
-	disk_stat_inc(mddev->gendisk, ios[rw]);
-	disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bi));
+	cpu = part_stat_lock();
+	part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
+	part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],
+		      bio_sectors(bi));
+	part_stat_unlock();
 
 	if (rw == READ &&
 	     mddev->reshape_position == MaxSector &&
@@ -3449,7 +3507,7 @@ static int make_request(struct request_queue *q, struct bio * bi)
 			
 	}
 	spin_lock_irq(&conf->device_lock);
-	remaining = --bi->bi_phys_segments;
+	remaining = raid5_dec_bi_phys_segments(bi);
 	spin_unlock_irq(&conf->device_lock);
 	if (remaining == 0) {
 
@@ -3692,7 +3750,9 @@ static inline sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *ski
 	clear_bit(STRIPE_INSYNC, &sh->state);
 	spin_unlock(&sh->lock);
 
-	handle_stripe(sh, NULL);
+	/* wait for any blocked device to be handled */
+	while(unlikely(!handle_stripe(sh, NULL)))
+		;
 	release_stripe(sh);
 
 	return STRIPE_SECTORS;
@@ -3731,7 +3791,7 @@ static int  retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio)
 		     sector += STRIPE_SECTORS,
 		     scnt++) {
 
-		if (scnt < raid_bio->bi_hw_segments)
+		if (scnt < raid5_bi_hw_segments(raid_bio))
 			/* already done this stripe */
 			continue;
 
@@ -3739,7 +3799,7 @@ static int  retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio)
 
 		if (!sh) {
 			/* failed to get a stripe - must wait */
-			raid_bio->bi_hw_segments = scnt;
+			raid5_set_bi_hw_segments(raid_bio, scnt);
 			conf->retry_read_aligned = raid_bio;
 			return handled;
 		}
@@ -3747,7 +3807,7 @@ static int  retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio)
 		set_bit(R5_ReadError, &sh->dev[dd_idx].flags);
 		if (!add_stripe_bio(sh, raid_bio, dd_idx, 0)) {
 			release_stripe(sh);
-			raid_bio->bi_hw_segments = scnt;
+			raid5_set_bi_hw_segments(raid_bio, scnt);
 			conf->retry_read_aligned = raid_bio;
 			return handled;
 		}
@@ -3757,7 +3817,7 @@ static int  retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio)
 		handled++;
 	}
 	spin_lock_irq(&conf->device_lock);
-	remaining = --raid_bio->bi_phys_segments;
+	remaining = raid5_dec_bi_phys_segments(raid_bio);
 	spin_unlock_irq(&conf->device_lock);
 	if (remaining == 0)
 		bio_endio(raid_bio, 0);
@@ -3811,10 +3871,8 @@ static void raid5d(mddev_t *mddev)
 
 		sh = __get_priority_stripe(conf);
 
-		if (!sh) {
-			async_tx_issue_pending_all();
+		if (!sh)
 			break;
-		}
 		spin_unlock_irq(&conf->device_lock);
 		
 		handled++;
@@ -3827,6 +3885,7 @@ static void raid5d(mddev_t *mddev)
 
 	spin_unlock_irq(&conf->device_lock);
 
+	async_tx_issue_pending_all();
 	unplug_slaves(mddev);
 
 	pr_debug("--- raid5d inactive\n");
@@ -4439,6 +4498,9 @@ static int raid5_check_reshape(mddev_t *mddev)
 		return -EINVAL; /* Cannot shrink array or change level yet */
 	if (mddev->delta_disks == 0)
 		return 0; /* nothing to do */
+	if (mddev->bitmap)
+		/* Cannot grow a bitmap yet */
+		return -EBUSY;
 
 	/* Can only proceed if there are plenty of stripe_heads.
 	 * We need a minimum of one full stripe,, and for sensible progress