btrfs: replace map_lookup->stripe_len by BTRFS_STRIPE_LEN

Currently btrfs doesn't support stripe lengths other than 64KiB.
This is already set in the tree-checker.

There is really no meaning to record that fixed value in map_lookup for
now, and can all be replaced with BTRFS_STRIPE_LEN.

Furthermore we can use the fix stripe length to do the following
optimization:

- Use BTRFS_STRIPE_LEN_SHIFT to replace some 64bit division
  Now we only need to do a right shift.

  And the value of BTRFS_STRIPE_LEN itself is already too large for bit
  shift, thus if we accidentally use BTRFS_STRIPE_LEN to do bit shift,
  a compiler warning would be triggered.

  Thus this bit shift optimization would be safe.

- Use BTRFS_STRIPE_LEN_MASK to calculate the offset inside a stripe

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 5fc670c..b274747 100644 (file)
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -1977,12 +1977,12 @@ int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
 
        map = em->map_lookup;
        data_stripe_length = em->orig_block_len;
-       io_stripe_size = map->stripe_len;
+       io_stripe_size = BTRFS_STRIPE_LEN;
        chunk_start = em->start;
 
        /* For RAID5/6 adjust to a full IO stripe length */
        if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
-               io_stripe_size = map->stripe_len * nr_data_stripes(map);
+               io_stripe_size = nr_data_stripes(map) << BTRFS_STRIPE_LEN_SHIFT;
 
        buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS);
        if (!buf) {
@@ -2000,8 +2000,10 @@ int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
                              data_stripe_length))
                        continue;
 
-               stripe_nr = physical - map->stripes[i].physical;
-               stripe_nr = div64_u64_rem(stripe_nr, map->stripe_len, &offset);
+               stripe_nr = (physical - map->stripes[i].physical) >>
+                           BTRFS_STRIPE_LEN_SHIFT;
+               offset = (physical - map->stripes[i].physical) &
+                        BTRFS_STRIPE_LEN_MASK;
 
                if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
                                 BTRFS_BLOCK_GROUP_RAID10)) {

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 69c93ae..190536b 100644 (file)
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -2722,7 +2722,7 @@ static int scrub_extent(struct scrub_ctx *sctx, struct map_lookup *map,
 
        if (flags & BTRFS_EXTENT_FLAG_DATA) {
                if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
-                       blocksize = map->stripe_len;
+                       blocksize = BTRFS_STRIPE_LEN;
                else
                        blocksize = sctx->fs_info->sectorsize;
                spin_lock(&sctx->stat_lock);
@@ -2731,7 +2731,7 @@ static int scrub_extent(struct scrub_ctx *sctx, struct map_lookup *map,
                spin_unlock(&sctx->stat_lock);
        } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
                if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
-                       blocksize = map->stripe_len;
+                       blocksize = BTRFS_STRIPE_LEN;
                else
                        blocksize = sctx->fs_info->nodesize;
                spin_lock(&sctx->stat_lock);
@@ -2920,9 +2920,9 @@ static int get_raid56_logic_offset(u64 physical, int num,
 
        *offset = last_offset;
        for (i = 0; i < data_stripes; i++) {
-               *offset = last_offset + i * map->stripe_len;
+               *offset = last_offset + (i << BTRFS_STRIPE_LEN_SHIFT);
 
-               stripe_nr = div64_u64(*offset, map->stripe_len);
+               stripe_nr = *offset >> BTRFS_STRIPE_LEN_SHIFT;
                stripe_nr = div_u64(stripe_nr, data_stripes);
 
                /* Work out the disk rotation on this stripe-set */
@@ -2935,7 +2935,7 @@ static int get_raid56_logic_offset(u64 physical, int num,
                if (stripe_index < num)
                        j++;
        }
-       *offset = last_offset + j * map->stripe_len;
+       *offset = last_offset + (j << BTRFS_STRIPE_LEN_SHIFT);
        return 1;
 }
 
@@ -3205,7 +3205,7 @@ static int scrub_raid56_data_stripe_for_parity(struct scrub_ctx *sctx,
        /* Path must not be populated */
        ASSERT(!path->nodes[0]);
 
-       while (cur_logical < logical + map->stripe_len) {
+       while (cur_logical < logical + BTRFS_STRIPE_LEN) {
                struct btrfs_io_context *bioc = NULL;
                struct btrfs_device *extent_dev;
                u64 extent_start;
@@ -3217,7 +3217,7 @@ static int scrub_raid56_data_stripe_for_parity(struct scrub_ctx *sctx,
                u64 extent_mirror_num;
 
                ret = find_first_extent_item(extent_root, path, cur_logical,
-                                            logical + map->stripe_len - cur_logical);
+                                            logical + BTRFS_STRIPE_LEN - cur_logical);
                /* No more extent item in this data stripe */
                if (ret > 0) {
                        ret = 0;
@@ -3231,7 +3231,7 @@ static int scrub_raid56_data_stripe_for_parity(struct scrub_ctx *sctx,
                /* Metadata should not cross stripe boundaries */
                if ((extent_flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) &&
                    does_range_cross_boundary(extent_start, extent_size,
-                                             logical, map->stripe_len)) {
+                                             logical, BTRFS_STRIPE_LEN)) {
                        btrfs_err(fs_info,
        "scrub: tree block %llu spanning stripes, ignored. logical=%llu",
                                  extent_start, logical);
@@ -3247,7 +3247,7 @@ static int scrub_raid56_data_stripe_for_parity(struct scrub_ctx *sctx,
 
                /* Truncate the range inside this data stripe */
                extent_size = min(extent_start + extent_size,
-                                 logical + map->stripe_len) - cur_logical;
+                                 logical + BTRFS_STRIPE_LEN) - cur_logical;
                extent_start = cur_logical;
                ASSERT(extent_size <= U32_MAX);
 
@@ -3320,8 +3320,7 @@ static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx,
        path->search_commit_root = 1;
        path->skip_locking = 1;
 
-       ASSERT(map->stripe_len <= U32_MAX);
-       nsectors = map->stripe_len >> fs_info->sectorsize_bits;
+       nsectors = BTRFS_STRIPE_LEN >> fs_info->sectorsize_bits;
        ASSERT(nsectors <= BITS_PER_LONG);
        sparity = kzalloc(sizeof(struct scrub_parity), GFP_NOFS);
        if (!sparity) {
@@ -3332,8 +3331,7 @@ static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx,
                return -ENOMEM;
        }
 
-       ASSERT(map->stripe_len <= U32_MAX);
-       sparity->stripe_len = map->stripe_len;
+       sparity->stripe_len = BTRFS_STRIPE_LEN;
        sparity->nsectors = nsectors;
        sparity->sctx = sctx;
        sparity->scrub_dev = sdev;
@@ -3344,7 +3342,7 @@ static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx,
 
        ret = 0;
        for (cur_logical = logic_start; cur_logical < logic_end;
-            cur_logical += map->stripe_len) {
+            cur_logical += BTRFS_STRIPE_LEN) {
                ret = scrub_raid56_data_stripe_for_parity(sctx, sparity, map,
                                                          sdev, path, cur_logical);
                if (ret < 0)
@@ -3536,7 +3534,7 @@ static u64 simple_stripe_full_stripe_len(const struct map_lookup *map)
        ASSERT(map->type & (BTRFS_BLOCK_GROUP_RAID0 |
                            BTRFS_BLOCK_GROUP_RAID10));
 
-       return map->num_stripes / map->sub_stripes * map->stripe_len;
+       return (map->num_stripes / map->sub_stripes) << BTRFS_STRIPE_LEN_SHIFT;
 }
 
 /* Get the logical bytenr for the stripe */
@@ -3552,7 +3550,8 @@ static u64 simple_stripe_get_logical(struct map_lookup *map,
         * (stripe_index / sub_stripes) gives how many data stripes we need to
         * skip.
         */
-       return (stripe_index / map->sub_stripes) * map->stripe_len + bg->start;
+       return ((stripe_index / map->sub_stripes) << BTRFS_STRIPE_LEN_SHIFT) +
+              bg->start;
 }
 
 /* Get the mirror number for the stripe */
@@ -3589,14 +3588,14 @@ static int scrub_simple_stripe(struct scrub_ctx *sctx,
                 * this stripe.
                 */
                ret = scrub_simple_mirror(sctx, extent_root, csum_root, bg, map,
-                                         cur_logical, map->stripe_len, device,
+                                         cur_logical, BTRFS_STRIPE_LEN, device,
                                          cur_physical, mirror_num);
                if (ret)
                        return ret;
                /* Skip to next stripe which belongs to the target device */
                cur_logical += logical_increment;
                /* For physical offset, we just go to next stripe */
-               cur_physical += map->stripe_len;
+               cur_physical += BTRFS_STRIPE_LEN;
        }
        return ret;
 }
@@ -3690,7 +3689,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
        if (profile & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
                ret = scrub_simple_stripe(sctx, root, csum_root, bg, map,
                                          scrub_dev, stripe_index);
-               offset = map->stripe_len * (stripe_index / map->sub_stripes);
+               offset = (stripe_index / map->sub_stripes) << BTRFS_STRIPE_LEN_SHIFT;
                goto out;
        }
 
@@ -3705,7 +3704,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
 
        /* Initialize @offset in case we need to go to out: label */
        get_raid56_logic_offset(physical, stripe_index, map, &offset, NULL);
-       increment = map->stripe_len * nr_data_stripes(map);
+       increment = nr_data_stripes(map) << BTRFS_STRIPE_LEN_SHIFT;
 
        /*
         * Due to the rotation, for RAID56 it's better to iterate each stripe
@@ -3736,13 +3735,13 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
                 * is still based on @mirror_num.
                 */
                ret = scrub_simple_mirror(sctx, root, csum_root, bg, map,
-                                         logical, map->stripe_len,
+                                         logical, BTRFS_STRIPE_LEN,
                                          scrub_dev, physical, 1);
                if (ret < 0)
                        goto out;
 next:
                logical += increment;
-               physical += map->stripe_len;
+               physical += BTRFS_STRIPE_LEN;
                spin_lock(&sctx->stat_lock);
                if (stop_loop)
                        sctx->stat.last_physical =

diff --git a/fs/btrfs/tests/extent-map-tests.c b/fs/btrfs/tests/extent-map-tests.c
index f2f2e11..ed0f36a 100644 (file)
--- a/fs/btrfs/tests/extent-map-tests.c
+++ b/fs/btrfs/tests/extent-map-tests.c
@@ -486,7 +486,6 @@ static int test_rmap_block(struct btrfs_fs_info *fs_info,
        em->map_lookup = map;
 
        map->num_stripes = test->num_stripes;
-       map->stripe_len = BTRFS_STRIPE_LEN;
        map->type = test->raid_type;
 
        for (i = 0; i < map->num_stripes; i++) {

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index c6d5928..d2b8b8a 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5125,7 +5125,7 @@ static void init_alloc_chunk_ctl_policy_regular(
        /* We don't want a chunk larger than 10% of writable space */
        ctl->max_chunk_size = min(mult_perc(fs_devices->total_rw_bytes, 10),
                                  ctl->max_chunk_size);
-       ctl->dev_extent_min = BTRFS_STRIPE_LEN * ctl->dev_stripes;
+       ctl->dev_extent_min = ctl->dev_stripes << BTRFS_STRIPE_LEN_SHIFT;
 }
 
 static void init_alloc_chunk_ctl_policy_zoned(
@@ -5407,7 +5407,6 @@ static struct btrfs_block_group *create_chunk(struct btrfs_trans_handle *trans,
                                                   j * ctl->stripe_size;
                }
        }
-       map->stripe_len = BTRFS_STRIPE_LEN;
        map->io_align = BTRFS_STRIPE_LEN;
        map->io_width = BTRFS_STRIPE_LEN;
        map->type = type;
@@ -5615,11 +5614,11 @@ int btrfs_chunk_alloc_add_chunk_item(struct btrfs_trans_handle *trans,
 
        btrfs_set_stack_chunk_length(chunk, bg->length);
        btrfs_set_stack_chunk_owner(chunk, BTRFS_EXTENT_TREE_OBJECTID);
-       btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
+       btrfs_set_stack_chunk_stripe_len(chunk, BTRFS_STRIPE_LEN);
        btrfs_set_stack_chunk_type(chunk, map->type);
        btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
-       btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
-       btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
+       btrfs_set_stack_chunk_io_align(chunk, BTRFS_STRIPE_LEN);
+       btrfs_set_stack_chunk_io_width(chunk, BTRFS_STRIPE_LEN);
        btrfs_set_stack_chunk_sector_size(chunk, fs_info->sectorsize);
        btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
 
@@ -5809,7 +5808,7 @@ unsigned long btrfs_full_stripe_len(struct btrfs_fs_info *fs_info,
        if (!WARN_ON(IS_ERR(em))) {
                map = em->map_lookup;
                if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
-                       len = map->stripe_len * nr_data_stripes(map);
+                       len = nr_data_stripes(map) << BTRFS_STRIPE_LEN_SHIFT;
                free_extent_map(em);
        }
        return len;
@@ -5975,7 +5974,6 @@ struct btrfs_discard_stripe *btrfs_map_discard(struct btrfs_fs_info *fs_info,
        u64 stripe_nr_end;
        u64 stripe_end_offset;
        u64 stripe_cnt;
-       u64 stripe_len;
        u64 stripe_offset;
        u32 stripe_index;
        u32 factor = 0;
@@ -5996,26 +5994,25 @@ struct btrfs_discard_stripe *btrfs_map_discard(struct btrfs_fs_info *fs_info,
        if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
                ret = -EOPNOTSUPP;
                goto out_free_map;
-}
+       }
 
        offset = logical - em->start;
        length = min_t(u64, em->start + em->len - logical, length);
        *length_ret = length;
 
-       stripe_len = map->stripe_len;
        /*
         * stripe_nr counts the total number of stripes we have to stride
         * to get to this block
         */
-       stripe_nr = div64_u64(offset, stripe_len);
+       stripe_nr = offset >> BTRFS_STRIPE_LEN_SHIFT;
 
        /* stripe_offset is the offset of this block in its stripe */
-       stripe_offset = offset - stripe_nr * stripe_len;
+       stripe_offset = offset - (stripe_nr << BTRFS_STRIPE_LEN_SHIFT);
 
-       stripe_nr_end = round_up(offset + length, map->stripe_len);
-       stripe_nr_end = div64_u64(stripe_nr_end, map->stripe_len);
+       stripe_nr_end = round_up(offset + length, BTRFS_STRIPE_LEN) >>
+                       BTRFS_STRIPE_LEN_SHIFT;
        stripe_cnt = stripe_nr_end - stripe_nr;
-       stripe_end_offset = stripe_nr_end * map->stripe_len -
+       stripe_end_offset = (stripe_nr_end << BTRFS_STRIPE_LEN_SHIFT) -
                            (offset + length);
        /*
         * after this, stripe_nr is the number of stripes on this
@@ -6057,15 +6054,15 @@ struct btrfs_discard_stripe *btrfs_map_discard(struct btrfs_fs_info *fs_info,
        for (i = 0; i < *num_stripes; i++) {
                stripes[i].physical =
                        map->stripes[stripe_index].physical +
-                       stripe_offset + stripe_nr * map->stripe_len;
+                       stripe_offset + (stripe_nr << BTRFS_STRIPE_LEN_SHIFT);
                stripes[i].dev = map->stripes[stripe_index].dev;
 
                if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
                                 BTRFS_BLOCK_GROUP_RAID10)) {
-                       stripes[i].length = stripes_per_dev * map->stripe_len;
+                       stripes[i].length = stripes_per_dev << BTRFS_STRIPE_LEN_SHIFT;
 
                        if (i / sub_stripes < remaining_stripes)
-                               stripes[i].length += map->stripe_len;
+                               stripes[i].length += BTRFS_STRIPE_LEN;
 
                        /*
                         * Special for the first stripe and
@@ -6304,22 +6301,32 @@ static u64 btrfs_max_io_len(struct map_lookup *map, enum btrfs_map_op op,
                            u64 offset, u64 *stripe_nr, u64 *stripe_offset,
                            u64 *full_stripe_start)
 {
-       u32 stripe_len = map->stripe_len;
-
        ASSERT(op != BTRFS_MAP_DISCARD);
 
        /*
         * Stripe_nr is the stripe where this block falls.  stripe_offset is
         * the offset of this block in its stripe.
         */
-       *stripe_nr = div64_u64_rem(offset, stripe_len, stripe_offset);
+       *stripe_offset = offset & BTRFS_STRIPE_LEN_MASK;
+       *stripe_nr = offset >> BTRFS_STRIPE_LEN_SHIFT;
        ASSERT(*stripe_offset < U32_MAX);
 
        if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
-               unsigned long full_stripe_len = stripe_len * nr_data_stripes(map);
+               unsigned long full_stripe_len = nr_data_stripes(map) <<
+                                               BTRFS_STRIPE_LEN_SHIFT;
 
+               /*
+                * For full stripe start, we use previously calculated
+                * @stripe_nr. Align it to nr_data_stripes, then multiply with
+                * STRIPE_LEN.
+                *
+                * By this we can avoid u64 division completely.  And we have
+                * to go rounddown(), not round_down(), as nr_data_stripes is
+                * not ensured to be power of 2.
+                */
                *full_stripe_start =
-                       div64_u64(offset, full_stripe_len) * full_stripe_len;
+                       rounddown(*stripe_nr, nr_data_stripes(map)) <<
+                       BTRFS_STRIPE_LEN_SHIFT;
 
                /*
                 * For writes to RAID56, allow to write a full stripe set, but
@@ -6334,7 +6341,7 @@ static u64 btrfs_max_io_len(struct map_lookup *map, enum btrfs_map_op op,
         * a single disk).
         */
        if (map->type & BTRFS_BLOCK_GROUP_STRIPE_MASK)
-               return stripe_len - *stripe_offset;
+               return BTRFS_STRIPE_LEN - *stripe_offset;
        return U64_MAX;
 }
 
@@ -6343,7 +6350,7 @@ static void set_io_stripe(struct btrfs_io_stripe *dst, const struct map_lookup *
 {
        dst->dev = map->stripes[stripe_index].dev;
        dst->physical = map->stripes[stripe_index].physical +
-                       stripe_offset + stripe_nr * map->stripe_len;
+                       stripe_offset + (stripe_nr << BTRFS_STRIPE_LEN_SHIFT);
 }
 
 int __btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
@@ -6357,7 +6364,6 @@ int __btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
        u64 map_offset;
        u64 stripe_offset;
        u64 stripe_nr;
-       u64 stripe_len;
        u32 stripe_index;
        int data_stripes;
        int i;
@@ -6384,7 +6390,6 @@ int __btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
 
        map = em->map_lookup;
        data_stripes = nr_data_stripes(map);
-       stripe_len = map->stripe_len;
 
        map_offset = logical - em->start;
        max_len = btrfs_max_io_len(map, op, map_offset, &stripe_nr,
@@ -6460,11 +6465,10 @@ int __btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
                }
 
        } else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
-               ASSERT(map->stripe_len == BTRFS_STRIPE_LEN);
                if (need_raid_map && (need_full_stripe(op) || mirror_num > 1)) {
                        /* push stripe_nr back to the start of the full stripe */
                        stripe_nr = div64_u64(raid56_full_stripe_start,
-                                       stripe_len * data_stripes);
+                                             data_stripes << BTRFS_STRIPE_LEN_SHIFT);
 
                        /* RAID[56] write or recovery. Return all stripes */
                        num_stripes = map->num_stripes;
@@ -6473,7 +6477,7 @@ int __btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
                        /* Return the length to the full stripe end */
                        *length = min(logical + *length,
                                      raid56_full_stripe_start + em->start +
-                                     data_stripes * stripe_len) - logical;
+                                     (data_stripes << BTRFS_STRIPE_LEN_SHIFT)) - logical;
                        stripe_index = 0;
                        stripe_offset = 0;
                } else {
@@ -6568,7 +6572,7 @@ int __btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
                tmp = stripe_nr * data_stripes;
                for (i = 0; i < data_stripes; i++)
                        bioc->raid_map[(i + rot) % num_stripes] =
-                               em->start + (tmp + i) * map->stripe_len;
+                               em->start + ((tmp + i) << BTRFS_STRIPE_LEN_SHIFT);
 
                bioc->raid_map[(i + rot) % map->num_stripes] = RAID5_P_STRIPE;
                if (map->type & BTRFS_BLOCK_GROUP_RAID6)
@@ -6941,7 +6945,6 @@ static int read_one_chunk(struct btrfs_key *key, struct extent_buffer *leaf,
        map->num_stripes = num_stripes;
        map->io_width = btrfs_chunk_io_width(leaf, chunk);
        map->io_align = btrfs_chunk_io_align(leaf, chunk);
-       map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
        map->type = type;
        /*
         * We can't use the sub_stripes value, as for profiles other than

diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 7e51f22..9f397b4 100644 (file)
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -17,7 +17,11 @@
 
 extern struct mutex uuid_mutex;
 
-#define BTRFS_STRIPE_LEN       SZ_64K
+#define BTRFS_STRIPE_LEN               SZ_64K
+#define BTRFS_STRIPE_LEN_SHIFT         (16)
+#define BTRFS_STRIPE_LEN_MASK          (BTRFS_STRIPE_LEN - 1)
+
+static_assert(const_ilog2(BTRFS_STRIPE_LEN) == BTRFS_STRIPE_LEN_SHIFT);
 
 /* Used by sanity check for btrfs_raid_types. */
 #define const_ffs(n) (__builtin_ctzll(n) + 1)
@@ -446,7 +450,6 @@ struct map_lookup {
        u64 type;
        int io_align;
        int io_width;
-       u32 stripe_len;
        int num_stripes;
        int sub_stripes;
        int verified_stripes; /* For mount time dev extent verification */