btrfs: zoned: fix stripe width calculation

The stripe offset calculation in the zoned code for raid0 and raid10
wrongly uses map->stripe_size to calculate it. In fact, map->stripe_size is
the size of the device extent composing the block group, which always is
the zone_size on the zoned setup.

Fix it by using BTRFS_STRIPE_LEN and BTRFS_STRIPE_LEN_SHIFT. Also, optimize
the calculation a bit by doing the common calculation only once.

Fixes: c0d90a79e8e6 ("btrfs: zoned: fix alloc_offset calculation for partly conventional block groups")
CC: stable@vger.kernel.org # 6.17+
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 8f006dff8893db426afee8e31069361b6a9fff96..b622c73fe30f97012d0567fc86a9bdbd6531566f 100644 (file)
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -1523,6 +1523,8 @@ static int btrfs_load_block_group_raid0(struct btrfs_block_group *bg,
                                        u64 last_alloc)
 {
        struct btrfs_fs_info *fs_info = bg->fs_info;
+       u64 stripe_nr = 0, stripe_offset = 0;
+       u32 stripe_index = 0;
 
        if ((map->type & BTRFS_BLOCK_GROUP_DATA) && !fs_info->stripe_root) {
                btrfs_err(fs_info, "zoned: data %s needs raid-stripe-tree",
@@ -1530,28 +1532,26 @@ static int btrfs_load_block_group_raid0(struct btrfs_block_group *bg,
                return -EINVAL;
        }
 
+       if (last_alloc) {
+               u32 factor = map->num_stripes;
+
+               stripe_nr = last_alloc >> BTRFS_STRIPE_LEN_SHIFT;
+               stripe_offset = last_alloc & BTRFS_STRIPE_LEN_MASK;
+               stripe_nr = div_u64_rem(stripe_nr, factor, &stripe_index);
+       }
+
        for (int i = 0; i < map->num_stripes; i++) {
                if (zone_info[i].alloc_offset == WP_MISSING_DEV)
                        continue;
 
                if (zone_info[i].alloc_offset == WP_CONVENTIONAL) {
-                       u64 stripe_nr, full_stripe_nr;
-                       u64 stripe_offset;
-                       int stripe_index;
 
-                       stripe_nr = div64_u64(last_alloc, map->stripe_size);
-                       stripe_offset = stripe_nr * map->stripe_size;
-                       full_stripe_nr = div_u64(stripe_nr, map->num_stripes);
-                       div_u64_rem(stripe_nr, map->num_stripes, &stripe_index);
-
-                       zone_info[i].alloc_offset =
-                               full_stripe_nr * map->stripe_size;
+                       zone_info[i].alloc_offset = btrfs_stripe_nr_to_offset(stripe_nr);
 
                        if (stripe_index > i)
-                               zone_info[i].alloc_offset += map->stripe_size;
+                               zone_info[i].alloc_offset += BTRFS_STRIPE_LEN;
                        else if (stripe_index == i)
-                               zone_info[i].alloc_offset +=
-                                       (last_alloc - stripe_offset);
+                               zone_info[i].alloc_offset += stripe_offset;
                }
 
                if (test_bit(0, active) != test_bit(i, active)) {
@@ -1575,6 +1575,8 @@ static int btrfs_load_block_group_raid10(struct btrfs_block_group *bg,
                                         u64 last_alloc)
 {
        struct btrfs_fs_info *fs_info = bg->fs_info;
+       u64 stripe_nr = 0, stripe_offset = 0;
+       u32 stripe_index = 0;
 
        if ((map->type & BTRFS_BLOCK_GROUP_DATA) && !fs_info->stripe_root) {
                btrfs_err(fs_info, "zoned: data %s needs raid-stripe-tree",
@@ -1582,6 +1584,14 @@ static int btrfs_load_block_group_raid10(struct btrfs_block_group *bg,
                return -EINVAL;
        }
 
+       if (last_alloc) {
+               u32 factor = map->num_stripes / map->sub_stripes;
+
+               stripe_nr = last_alloc >> BTRFS_STRIPE_LEN_SHIFT;
+               stripe_offset = last_alloc & BTRFS_STRIPE_LEN_MASK;
+               stripe_nr = div_u64_rem(stripe_nr, factor, &stripe_index);
+       }
+
        for (int i = 0; i < map->num_stripes; i++) {
                if (zone_info[i].alloc_offset == WP_MISSING_DEV)
                        continue;
@@ -1595,26 +1605,12 @@ static int btrfs_load_block_group_raid10(struct btrfs_block_group *bg,
                }
 
                if (zone_info[i].alloc_offset == WP_CONVENTIONAL) {
-                       u64 stripe_nr, full_stripe_nr;
-                       u64 stripe_offset;
-                       int stripe_index;
-
-                       stripe_nr = div64_u64(last_alloc, map->stripe_size);
-                       stripe_offset = stripe_nr * map->stripe_size;
-                       full_stripe_nr = div_u64(stripe_nr,
-                                        map->num_stripes / map->sub_stripes);
-                       div_u64_rem(stripe_nr,
-                                   (map->num_stripes / map->sub_stripes),
-                                   &stripe_index);
-
-                       zone_info[i].alloc_offset =
-                               full_stripe_nr * map->stripe_size;
+                       zone_info[i].alloc_offset = btrfs_stripe_nr_to_offset(stripe_nr);
 
                        if (stripe_index > (i / map->sub_stripes))
-                               zone_info[i].alloc_offset += map->stripe_size;
+                               zone_info[i].alloc_offset += BTRFS_STRIPE_LEN;
                        else if (stripe_index == (i / map->sub_stripes))
-                               zone_info[i].alloc_offset +=
-                                       (last_alloc - stripe_offset);
+                               zone_info[i].alloc_offset += stripe_offset;
                }
 
                if ((i % map->sub_stripes) == 0) {