Btrfs: Make raid_map array be inlined in btrfs_bio structure

It can make code more simple and clear, we need not care about
free bbio and raid_map together.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>

5 files changed, 105 insertions, 125 deletions

diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 8ab2a17bbba8..e301d3302edf 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -79,13 +79,6 @@ struct btrfs_raid_bio {
 	struct btrfs_fs_info *fs_info;
 	struct btrfs_bio *bbio;
 
-	/*
-	 * logical block numbers for the start of each stripe
-	 * The last one or two are p/q.  These are sorted,
-	 * so raid_map[0] is the start of our full stripe
-	 */
-	u64 *raid_map;
-
 	/* while we're doing rmw on a stripe
 	 * we put it into a hash table so we can
 	 * lock the stripe and merge more rbios
@@ -303,7 +296,7 @@ static void cache_rbio_pages(struct btrfs_raid_bio *rbio)
  */
 static int rbio_bucket(struct btrfs_raid_bio *rbio)
 {
-	u64 num = rbio->raid_map[0];
+	u64 num = rbio->bbio->raid_map[0];
 
 	/*
 	 * we shift down quite a bit.  We're using byte
@@ -606,8 +599,8 @@ static int rbio_can_merge(struct btrfs_raid_bio *last,
 	    test_bit(RBIO_CACHE_BIT, &cur->flags))
 		return 0;
 
-	if (last->raid_map[0] !=
-	    cur->raid_map[0])
+	if (last->bbio->raid_map[0] !=
+	    cur->bbio->raid_map[0])
 		return 0;
 
 	/* we can't merge with different operations */
@@ -689,7 +682,7 @@ static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
 	spin_lock_irqsave(&h->lock, flags);
 	list_for_each_entry(cur, &h->hash_list, hash_list) {
 		walk++;
-		if (cur->raid_map[0] == rbio->raid_map[0]) {
+		if (cur->bbio->raid_map[0] == rbio->bbio->raid_map[0]) {
 			spin_lock(&cur->bio_list_lock);
 
 			/* can we steal this cached rbio's pages? */
@@ -842,18 +835,16 @@ done_nolock:
 }
 
 static inline void
-__free_bbio_and_raid_map(struct btrfs_bio *bbio, u64 *raid_map, int need)
+__free_bbio(struct btrfs_bio *bbio, int need)
 {
-	if (need) {
-		kfree(raid_map);
+	if (need)
 		kfree(bbio);
-	}
 }
 
-static inline void free_bbio_and_raid_map(struct btrfs_raid_bio *rbio)
+static inline void free_bbio(struct btrfs_raid_bio *rbio)
 {
-	__free_bbio_and_raid_map(rbio->bbio, rbio->raid_map,
-			!test_bit(RBIO_HOLD_BBIO_MAP_BIT, &rbio->flags));
+	__free_bbio(rbio->bbio,
+		    !test_bit(RBIO_HOLD_BBIO_MAP_BIT, &rbio->flags));
 }
 
 static void __free_raid_bio(struct btrfs_raid_bio *rbio)
@@ -875,7 +866,7 @@ static void __free_raid_bio(struct btrfs_raid_bio *rbio)
 		}
 	}
 
-	free_bbio_and_raid_map(rbio);
+	free_bbio(rbio);
 
 	kfree(rbio);
 }
@@ -985,8 +976,7 @@ static unsigned long rbio_nr_pages(unsigned long stripe_len, int nr_stripes)
  * this does not allocate any pages for rbio->pages.
  */
 static struct btrfs_raid_bio *alloc_rbio(struct btrfs_root *root,
-			  struct btrfs_bio *bbio, u64 *raid_map,
-			  u64 stripe_len)
+			  struct btrfs_bio *bbio, u64 stripe_len)
 {
 	struct btrfs_raid_bio *rbio;
 	int nr_data = 0;
@@ -1007,7 +997,6 @@ static struct btrfs_raid_bio *alloc_rbio(struct btrfs_root *root,
 	INIT_LIST_HEAD(&rbio->stripe_cache);
 	INIT_LIST_HEAD(&rbio->hash_list);
 	rbio->bbio = bbio;
-	rbio->raid_map = raid_map;
 	rbio->fs_info = root->fs_info;
 	rbio->stripe_len = stripe_len;
 	rbio->nr_pages = num_pages;
@@ -1028,7 +1017,7 @@ static struct btrfs_raid_bio *alloc_rbio(struct btrfs_root *root,
 	rbio->bio_pages = p + sizeof(struct page *) * num_pages;
 	rbio->dbitmap = p + sizeof(struct page *) * num_pages * 2;
 
-	if (raid_map[real_stripes - 1] == RAID6_Q_STRIPE)
+	if (bbio->raid_map[real_stripes - 1] == RAID6_Q_STRIPE)
 		nr_data = real_stripes - 2;
 	else
 		nr_data = real_stripes - 1;
@@ -1182,7 +1171,7 @@ static void index_rbio_pages(struct btrfs_raid_bio *rbio)
 	spin_lock_irq(&rbio->bio_list_lock);
 	bio_list_for_each(bio, &rbio->bio_list) {
 		start = (u64)bio->bi_iter.bi_sector << 9;
-		stripe_offset = start - rbio->raid_map[0];
+		stripe_offset = start - rbio->bbio->raid_map[0];
 		page_index = stripe_offset >> PAGE_CACHE_SHIFT;
 
 		for (i = 0; i < bio->bi_vcnt; i++) {
@@ -1402,7 +1391,7 @@ static int find_logical_bio_stripe(struct btrfs_raid_bio *rbio,
 	logical <<= 9;
 
 	for (i = 0; i < rbio->nr_data; i++) {
-		stripe_start = rbio->raid_map[i];
+		stripe_start = rbio->bbio->raid_map[i];
 		if (logical >= stripe_start &&
 		    logical < stripe_start + rbio->stripe_len) {
 			return i;
@@ -1776,17 +1765,16 @@ static void btrfs_raid_unplug(struct blk_plug_cb *cb, bool from_schedule)
  * our main entry point for writes from the rest of the FS.
  */
 int raid56_parity_write(struct btrfs_root *root, struct bio *bio,
-			struct btrfs_bio *bbio, u64 *raid_map,
-			u64 stripe_len)
+			struct btrfs_bio *bbio, u64 stripe_len)
 {
 	struct btrfs_raid_bio *rbio;
 	struct btrfs_plug_cb *plug = NULL;
 	struct blk_plug_cb *cb;
 	int ret;
 
-	rbio = alloc_rbio(root, bbio, raid_map, stripe_len);
+	rbio = alloc_rbio(root, bbio, stripe_len);
 	if (IS_ERR(rbio)) {
-		__free_bbio_and_raid_map(bbio, raid_map, 1);
+		__free_bbio(bbio, 1);
 		return PTR_ERR(rbio);
 	}
 	bio_list_add(&rbio->bio_list, bio);
@@ -1885,7 +1873,7 @@ static void __raid_recover_end_io(struct btrfs_raid_bio *rbio)
 		}
 
 		/* all raid6 handling here */
-		if (rbio->raid_map[rbio->real_stripes - 1] ==
+		if (rbio->bbio->raid_map[rbio->real_stripes - 1] ==
 		    RAID6_Q_STRIPE) {
 
 			/*
@@ -1922,8 +1910,9 @@ static void __raid_recover_end_io(struct btrfs_raid_bio *rbio)
 			 * here due to a crc mismatch and we can't give them the
 			 * data they want
 			 */
-			if (rbio->raid_map[failb] == RAID6_Q_STRIPE) {
-				if (rbio->raid_map[faila] == RAID5_P_STRIPE) {
+			if (rbio->bbio->raid_map[failb] == RAID6_Q_STRIPE) {
+				if (rbio->bbio->raid_map[faila] ==
+				    RAID5_P_STRIPE) {
 					err = -EIO;
 					goto cleanup;
 				}
@@ -1934,7 +1923,7 @@ static void __raid_recover_end_io(struct btrfs_raid_bio *rbio)
 				goto pstripe;
 			}
 
-			if (rbio->raid_map[failb] == RAID5_P_STRIPE) {
+			if (rbio->bbio->raid_map[failb] == RAID5_P_STRIPE) {
 				raid6_datap_recov(rbio->real_stripes,
 						  PAGE_SIZE, faila, pointers);
 			} else {
@@ -2156,15 +2145,15 @@ cleanup:
  * of the drive.
  */
 int raid56_parity_recover(struct btrfs_root *root, struct bio *bio,
-			  struct btrfs_bio *bbio, u64 *raid_map,
-			  u64 stripe_len, int mirror_num, int generic_io)
+			  struct btrfs_bio *bbio, u64 stripe_len,
+			  int mirror_num, int generic_io)
 {
 	struct btrfs_raid_bio *rbio;
 	int ret;
 
-	rbio = alloc_rbio(root, bbio, raid_map, stripe_len);
+	rbio = alloc_rbio(root, bbio, stripe_len);
 	if (IS_ERR(rbio)) {
-		__free_bbio_and_raid_map(bbio, raid_map, generic_io);
+		__free_bbio(bbio, generic_io);
 		return PTR_ERR(rbio);
 	}
 
@@ -2175,7 +2164,7 @@ int raid56_parity_recover(struct btrfs_root *root, struct bio *bio,
 	rbio->faila = find_logical_bio_stripe(rbio, bio);
 	if (rbio->faila == -1) {
 		BUG();
-		__free_bbio_and_raid_map(bbio, raid_map, generic_io);
+		__free_bbio(bbio, generic_io);
 		kfree(rbio);
 		return -EIO;
 	}
@@ -2240,14 +2229,14 @@ static void read_rebuild_work(struct btrfs_work *work)
 
 struct btrfs_raid_bio *
 raid56_parity_alloc_scrub_rbio(struct btrfs_root *root, struct bio *bio,
-			       struct btrfs_bio *bbio, u64 *raid_map,
-			       u64 stripe_len, struct btrfs_device *scrub_dev,
+			       struct btrfs_bio *bbio, u64 stripe_len,
+			       struct btrfs_device *scrub_dev,
 			       unsigned long *dbitmap, int stripe_nsectors)
 {
 	struct btrfs_raid_bio *rbio;
 	int i;
 
-	rbio = alloc_rbio(root, bbio, raid_map, stripe_len);
+	rbio = alloc_rbio(root, bbio, stripe_len);
 	if (IS_ERR(rbio))
 		return NULL;
 	bio_list_add(&rbio->bio_list, bio);
@@ -2279,10 +2268,10 @@ void raid56_parity_add_scrub_pages(struct btrfs_raid_bio *rbio,
 	int stripe_offset;
 	int index;
 
-	ASSERT(logical >= rbio->raid_map[0]);
-	ASSERT(logical + PAGE_SIZE <= rbio->raid_map[0] +
+	ASSERT(logical >= rbio->bbio->raid_map[0]);
+	ASSERT(logical + PAGE_SIZE <= rbio->bbio->raid_map[0] +
 				rbio->stripe_len * rbio->nr_data);
-	stripe_offset = (int)(logical - rbio->raid_map[0]);
+	stripe_offset = (int)(logical - rbio->bbio->raid_map[0]);
 	index = stripe_offset >> PAGE_CACHE_SHIFT;
 	rbio->bio_pages[index] = page;
 }
diff --git a/fs/btrfs/raid56.h b/fs/btrfs/raid56.h
index 31d4a157b5e3..2b5d7977d83b 100644
--- a/fs/btrfs/raid56.h
+++ b/fs/btrfs/raid56.h
@@ -43,16 +43,15 @@ struct btrfs_raid_bio;
 struct btrfs_device;
 
 int raid56_parity_recover(struct btrfs_root *root, struct bio *bio,
-			  struct btrfs_bio *bbio, u64 *raid_map,
-			  u64 stripe_len, int mirror_num, int generic_io);
+			  struct btrfs_bio *bbio, u64 stripe_len,
+			  int mirror_num, int generic_io);
 int raid56_parity_write(struct btrfs_root *root, struct bio *bio,
-			       struct btrfs_bio *bbio, u64 *raid_map,
-			       u64 stripe_len);
+			       struct btrfs_bio *bbio, u64 stripe_len);
 
 struct btrfs_raid_bio *
 raid56_parity_alloc_scrub_rbio(struct btrfs_root *root, struct bio *bio,
-			       struct btrfs_bio *bbio, u64 *raid_map,
-			       u64 stripe_len, struct btrfs_device *scrub_dev,
+			       struct btrfs_bio *bbio, u64 stripe_len,
+			       struct btrfs_device *scrub_dev,
 			       unsigned long *dbitmap, int stripe_nsectors);
 void raid56_parity_add_scrub_pages(struct btrfs_raid_bio *rbio,
 				   struct page *page, u64 logical);
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 673e32be88fa..9d07c981ec82 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -66,7 +66,6 @@ struct scrub_ctx;
 struct scrub_recover {
 	atomic_t		refs;
 	struct btrfs_bio	*bbio;
-	u64			*raid_map;
 	u64			map_length;
 };
 
@@ -857,7 +856,6 @@ static inline void scrub_put_recover(struct scrub_recover *recover)
 {
 	if (atomic_dec_and_test(&recover->refs)) {
 		kfree(recover->bbio);
-		kfree(recover->raid_map);
 		kfree(recover);
 	}
 }
@@ -1296,12 +1294,12 @@ out:
 	return 0;
 }
 
-static inline int scrub_nr_raid_mirrors(struct btrfs_bio *bbio, u64 *raid_map)
+static inline int scrub_nr_raid_mirrors(struct btrfs_bio *bbio)
 {
-	if (raid_map) {
+	if (bbio->raid_map) {
 		int real_stripes = bbio->num_stripes - bbio->num_tgtdevs;
 
-		if (raid_map[real_stripes - 1] == RAID6_Q_STRIPE)
+		if (bbio->raid_map[real_stripes - 1] == RAID6_Q_STRIPE)
 			return 3;
 		else
 			return 2;
@@ -1347,7 +1345,6 @@ static int scrub_setup_recheck_block(struct scrub_ctx *sctx,
 {
 	struct scrub_recover *recover;
 	struct btrfs_bio *bbio;
-	u64 *raid_map;
 	u64 sublen;
 	u64 mapped_length;
 	u64 stripe_offset;
@@ -1368,35 +1365,31 @@ static int scrub_setup_recheck_block(struct scrub_ctx *sctx,
 		sublen = min_t(u64, length, PAGE_SIZE);
 		mapped_length = sublen;
 		bbio = NULL;
-		raid_map = NULL;
 
 		/*
 		 * with a length of PAGE_SIZE, each returned stripe
 		 * represents one mirror
 		 */
 		ret = btrfs_map_sblock(fs_info, REQ_GET_READ_MIRRORS, logical,
-				       &mapped_length, &bbio, 0, &raid_map);
+				       &mapped_length, &bbio, 0, 1);
 		if (ret || !bbio || mapped_length < sublen) {
 			kfree(bbio);
-			kfree(raid_map);
 			return -EIO;
 		}
 
 		recover = kzalloc(sizeof(struct scrub_recover), GFP_NOFS);
 		if (!recover) {
 			kfree(bbio);
-			kfree(raid_map);
 			return -ENOMEM;
 		}
 
 		atomic_set(&recover->refs, 1);
 		recover->bbio = bbio;
-		recover->raid_map = raid_map;
 		recover->map_length = mapped_length;
 
 		BUG_ON(page_index >= SCRUB_PAGES_PER_RD_BIO);
 
-		nmirrors = scrub_nr_raid_mirrors(bbio, raid_map);
+		nmirrors = scrub_nr_raid_mirrors(bbio);
 		for (mirror_index = 0; mirror_index < nmirrors;
 		     mirror_index++) {
 			struct scrub_block *sblock;
@@ -1420,7 +1413,7 @@ leave_nomem:
 			sblock->pagev[page_index] = page;
 			page->logical = logical;
 
-			scrub_stripe_index_and_offset(logical, raid_map,
+			scrub_stripe_index_and_offset(logical, bbio->raid_map,
 						      mapped_length,
 						      bbio->num_stripes -
 						      bbio->num_tgtdevs,
@@ -1469,7 +1462,7 @@ static void scrub_bio_wait_endio(struct bio *bio, int error)
 
 static inline int scrub_is_page_on_raid56(struct scrub_page *page)
 {
-	return page->recover && page->recover->raid_map;
+	return page->recover && page->recover->bbio->raid_map;
 }
 
 static int scrub_submit_raid56_bio_wait(struct btrfs_fs_info *fs_info,
@@ -1486,7 +1479,6 @@ static int scrub_submit_raid56_bio_wait(struct btrfs_fs_info *fs_info,
 	bio->bi_end_io = scrub_bio_wait_endio;
 
 	ret = raid56_parity_recover(fs_info->fs_root, bio, page->recover->bbio,
-				    page->recover->raid_map,
 				    page->recover->map_length,
 				    page->mirror_num, 0);
 	if (ret)
@@ -2716,7 +2708,6 @@ static void scrub_parity_check_and_repair(struct scrub_parity *sparity)
 	struct btrfs_raid_bio *rbio;
 	struct scrub_page *spage;
 	struct btrfs_bio *bbio = NULL;
-	u64 *raid_map = NULL;
 	u64 length;
 	int ret;
 
@@ -2727,8 +2718,8 @@ static void scrub_parity_check_and_repair(struct scrub_parity *sparity)
 	length = sparity->logic_end - sparity->logic_start + 1;
 	ret = btrfs_map_sblock(sctx->dev_root->fs_info, WRITE,
 			       sparity->logic_start,
-			       &length, &bbio, 0, &raid_map);
-	if (ret || !bbio || !raid_map)
+			       &length, &bbio, 0, 1);
+	if (ret || !bbio || !bbio->raid_map)
 		goto bbio_out;
 
 	bio = btrfs_io_bio_alloc(GFP_NOFS, 0);
@@ -2740,8 +2731,7 @@ static void scrub_parity_check_and_repair(struct scrub_parity *sparity)
 	bio->bi_end_io = scrub_parity_bio_endio;
 
 	rbio = raid56_parity_alloc_scrub_rbio(sctx->dev_root, bio, bbio,
-					      raid_map, length,
-					      sparity->scrub_dev,
+					      length, sparity->scrub_dev,
 					      sparity->dbitmap,
 					      sparity->nsectors);
 	if (!rbio)
@@ -2759,7 +2749,6 @@ rbio_out:
 	bio_put(bio);
 bbio_out:
 	kfree(bbio);
-	kfree(raid_map);
 	bitmap_or(sparity->ebitmap, sparity->ebitmap, sparity->dbitmap,
 		  sparity->nsectors);
 	spin_lock(&sctx->stat_lock);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 711ce38543a1..c0f1d524c371 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -4876,8 +4876,7 @@ static inline int parity_smaller(u64 a, u64 b)
 }
 
 /* Bubble-sort the stripe set to put the parity/syndrome stripes last */
-static void sort_parity_stripes(struct btrfs_bio *bbio, u64 *raid_map,
-				int num_stripes)
+static void sort_parity_stripes(struct btrfs_bio *bbio, int num_stripes)
 {
 	struct btrfs_bio_stripe s;
 	int i;
@@ -4887,13 +4886,14 @@ static void sort_parity_stripes(struct btrfs_bio *bbio, u64 *raid_map,
 	while (again) {
 		again = 0;
 		for (i = 0; i < num_stripes - 1; i++) {
-			if (parity_smaller(raid_map[i], raid_map[i+1])) {
+			if (parity_smaller(bbio->raid_map[i],
+					   bbio->raid_map[i+1])) {
 				s = bbio->stripes[i];
-				l = raid_map[i];
+				l = bbio->raid_map[i];
 				bbio->stripes[i] = bbio->stripes[i+1];
-				raid_map[i] = raid_map[i+1];
+				bbio->raid_map[i] = bbio->raid_map[i+1];
 				bbio->stripes[i+1] = s;
-				raid_map[i+1] = l;
+				bbio->raid_map[i+1] = l;
 
 				again = 1;
 			}
@@ -4904,7 +4904,7 @@ static void sort_parity_stripes(struct btrfs_bio *bbio, u64 *raid_map,
 static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
 			     u64 logical, u64 *length,
 			     struct btrfs_bio **bbio_ret,
-			     int mirror_num, u64 **raid_map_ret)
+			     int mirror_num, int need_raid_map)
 {
 	struct extent_map *em;
 	struct map_lookup *map;
@@ -4917,7 +4917,6 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
 	u64 stripe_nr_orig;
 	u64 stripe_nr_end;
 	u64 stripe_len;
-	u64 *raid_map = NULL;
 	int stripe_index;
 	int i;
 	int ret = 0;
@@ -5039,7 +5038,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
 		u64 physical_of_found = 0;
 
 		ret = __btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS,
-			     logical, &tmp_length, &tmp_bbio, 0, NULL);
+			     logical, &tmp_length, &tmp_bbio, 0, 0);
 		if (ret) {
 			WARN_ON(tmp_bbio != NULL);
 			goto out;
@@ -5160,13 +5159,9 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
 
 	} else if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
 				BTRFS_BLOCK_GROUP_RAID6)) {
-		u64 tmp;
-
-		if (raid_map_ret &&
+		if (need_raid_map &&
 		    ((rw & (REQ_WRITE | REQ_GET_READ_MIRRORS)) ||
 		     mirror_num > 1)) {
-			int i, rot;
-
 			/* push stripe_nr back to the start of the full stripe */
 			stripe_nr = raid56_full_stripe_start;
 			do_div(stripe_nr, stripe_len * nr_data_stripes(map));
@@ -5175,32 +5170,12 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
 			num_stripes = map->num_stripes;
 			max_errors = nr_parity_stripes(map);
 
-			raid_map = kmalloc_array(num_stripes, sizeof(u64),
-					   GFP_NOFS);
-			if (!raid_map) {
-				ret = -ENOMEM;
-				goto out;
-			}
-
-			/* Work out the disk rotation on this stripe-set */
-			tmp = stripe_nr;
-			rot = do_div(tmp, num_stripes);
-
-			/* Fill in the logical address of each stripe */
-			tmp = stripe_nr * nr_data_stripes(map);
-			for (i = 0; i < nr_data_stripes(map); i++)
-				raid_map[(i+rot) % num_stripes] =
-					em->start + (tmp + i) * map->stripe_len;
-
-			raid_map[(i+rot) % map->num_stripes] = RAID5_P_STRIPE;
-			if (map->type & BTRFS_BLOCK_GROUP_RAID6)
-				raid_map[(i+rot+1) % num_stripes] =
-					RAID6_Q_STRIPE;
-
 			*length = map->stripe_len;
 			stripe_index = 0;
 			stripe_offset = 0;
 		} else {
+			u64 tmp;
+
 			/*
 			 * Mirror #0 or #1 means the original data block.
 			 * Mirror #2 is RAID5 parity block.
@@ -5241,7 +5216,6 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
 	bbio = kzalloc(btrfs_bio_size(num_alloc_stripes, tgtdev_indexes),
 		       GFP_NOFS);
 	if (!bbio) {
-		kfree(raid_map);
 		ret = -ENOMEM;
 		goto out;
 	}
@@ -5249,6 +5223,34 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
 	if (dev_replace_is_ongoing)
 		bbio->tgtdev_map = (int *)(bbio->stripes + num_alloc_stripes);
 
+	/* build raid_map */
+	if (map->type & (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6) &&
+	    need_raid_map && ((rw & (REQ_WRITE | REQ_GET_READ_MIRRORS)) ||
+	    mirror_num > 1)) {
+		u64 tmp;
+		int i, rot;
+
+		bbio->raid_map = (u64 *)((void *)bbio->stripes +
+				 sizeof(struct btrfs_bio_stripe) *
+				 num_alloc_stripes +
+				 sizeof(int) * tgtdev_indexes);
+
+		/* Work out the disk rotation on this stripe-set */
+		tmp = stripe_nr;
+		rot = do_div(tmp, num_stripes);
+
+		/* Fill in the logical address of each stripe */
+		tmp = stripe_nr * nr_data_stripes(map);
+		for (i = 0; i < nr_data_stripes(map); i++)
+			bbio->raid_map[(i+rot) % num_stripes] =
+				em->start + (tmp + i) * map->stripe_len;
+
+		bbio->raid_map[(i+rot) % map->num_stripes] = RAID5_P_STRIPE;
+		if (map->type & BTRFS_BLOCK_GROUP_RAID6)
+			bbio->raid_map[(i+rot+1) % num_stripes] =
+				RAID6_Q_STRIPE;
+	}
+
 	if (rw & REQ_DISCARD) {
 		int factor = 0;
 		int sub_stripes = 0;
@@ -5332,8 +5334,8 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
 	if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS))
 		max_errors = btrfs_chunk_max_errors(map);
 
-	if (raid_map)
-		sort_parity_stripes(bbio, raid_map, num_stripes);
+	if (bbio->raid_map)
+		sort_parity_stripes(bbio, num_stripes);
 
 	tgtdev_indexes = 0;
 	if (dev_replace_is_ongoing && (rw & (REQ_WRITE | REQ_DISCARD)) &&
@@ -5438,9 +5440,6 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
 		bbio->stripes[0].physical = physical_to_patch_in_first_stripe;
 		bbio->mirror_num = map->num_stripes + 1;
 	}
-
-	if (raid_map_ret)
-		*raid_map_ret = raid_map;
 out:
 	if (dev_replace_is_ongoing)
 		btrfs_dev_replace_unlock(dev_replace);
@@ -5453,17 +5452,17 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
 		      struct btrfs_bio **bbio_ret, int mirror_num)
 {
 	return __btrfs_map_block(fs_info, rw, logical, length, bbio_ret,
-				 mirror_num, NULL);
+				 mirror_num, 0);
 }
 
 /* For Scrub/replace */
 int btrfs_map_sblock(struct btrfs_fs_info *fs_info, int rw,
 		     u64 logical, u64 *length,
 		     struct btrfs_bio **bbio_ret, int mirror_num,
-		     u64 **raid_map_ret)
+		     int need_raid_map)
 {
 	return __btrfs_map_block(fs_info, rw, logical, length, bbio_ret,
-				 mirror_num, raid_map_ret);
+				 mirror_num, need_raid_map);
 }
 
 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
@@ -5802,7 +5801,6 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
 	u64 logical = (u64)bio->bi_iter.bi_sector << 9;
 	u64 length = 0;
 	u64 map_length;
-	u64 *raid_map = NULL;
 	int ret;
 	int dev_nr = 0;
 	int total_devs = 1;
@@ -5813,7 +5811,7 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
 
 	btrfs_bio_counter_inc_blocked(root->fs_info);
 	ret = __btrfs_map_block(root->fs_info, rw, logical, &map_length, &bbio,
-			      mirror_num, &raid_map);
+			      mirror_num, 1);
 	if (ret) {
 		btrfs_bio_counter_dec(root->fs_info);
 		return ret;
@@ -5826,15 +5824,13 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
 	bbio->fs_info = root->fs_info;
 	atomic_set(&bbio->stripes_pending, bbio->num_stripes);
 
-	if (raid_map) {
+	if (bbio->raid_map) {
 		/* In this case, map_length has been set to the length of
 		   a single stripe; not the whole write */
 		if (rw & WRITE) {
-			ret = raid56_parity_write(root, bio, bbio,
-						  raid_map, map_length);
+			ret = raid56_parity_write(root, bio, bbio, map_length);
 		} else {
-			ret = raid56_parity_recover(root, bio, bbio,
-						    raid_map, map_length,
+			ret = raid56_parity_recover(root, bio, bbio, map_length,
 						    mirror_num, 1);
 		}
 
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index d6fe73c0f4a2..fb0e8c3f296e 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -307,6 +307,12 @@ struct btrfs_bio {
 	int mirror_num;
 	int num_tgtdevs;
 	int *tgtdev_map;
+	/*
+	 * logical block numbers for the start of each stripe
+	 * The last one or two are p/q.  These are sorted,
+	 * so raid_map[0] is the start of our full stripe
+	 */
+	u64 *raid_map;
 	struct btrfs_bio_stripe stripes[];
 };
 
@@ -392,7 +398,8 @@ int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
 #define btrfs_bio_size(total_stripes, real_stripes)		\
 	(sizeof(struct btrfs_bio) +				\
 	 (sizeof(struct btrfs_bio_stripe) * (total_stripes)) +	\
-	 (sizeof(int) * (real_stripes)))
+	 (sizeof(int) * (real_stripes)) +			\
+	 (sizeof(u64) * (real_stripes)))
 
 int btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
 		    u64 logical, u64 *length,
@@ -400,7 +407,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
 int btrfs_map_sblock(struct btrfs_fs_info *fs_info, int rw,
 		     u64 logical, u64 *length,
 		     struct btrfs_bio **bbio_ret, int mirror_num,
-		     u64 **raid_map_ret);
+		     int need_raid_map);
 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
 		     u64 chunk_start, u64 physical, u64 devid,
 		     u64 **logical, int *naddrs, int *stripe_len);