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);