[PATCH 07/16] btrfs: zoned: Cache superblock location in btrfs_zoned_device_info

Pankaj Raghav
2022-04-27T16:04:44Z

Instead of calculating the superblock location every time, cache the
superblock zone location in btrfs_zoned_device_info struct and use it to
locate the zone index.

The functions such as btrfs_sb_log_location_bdev() and
btrfs_reset_sb_log_zones() which work directly on block_device shall
continue to use the sb_zone_number because btrfs_zoned_device_info
struct might not have been initialized at that point.

This patch will enable non power-of-2 zoned devices to not perform
division to lookup superblock and its mirror location.

Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
---
fs/btrfs/zoned.c | 13 +++++++++----
fs/btrfs/zoned.h | 1 +
2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 1b1b310c3c51..6f76942d0ea5 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -512,6 +512,11 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device, bool populate_cache)
max_active_zones - nactive);
}

+ /* Cache the sb zone number */
+ for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; ++i) {
+ zone_info->sb_zone_location[i] =
+ sb_zone_number(zone_info->zone_size_shift, i);
+ }
/* Validate superblock log */
nr_zones = BTRFS_NR_SB_LOG_ZONES;
for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
@@ -519,7 +524,7 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device, bool populate_cache)
u64 sb_wp;
int sb_pos = BTRFS_NR_SB_LOG_ZONES * i;

- sb_zone = sb_zone_number(zone_info->zone_size_shift, i);
+ sb_zone = zone_info->sb_zone_location[i];
if (sb_zone + 1 >= zone_info->nr_zones)
continue;

@@ -867,7 +872,7 @@ int btrfs_sb_log_location(struct btrfs_device *device, int mirror, int rw,
return 0;
}

- zone_num = sb_zone_number(zinfo->zone_size_shift, mirror);
+ zone_num = zinfo->sb_zone_location[mirror];
if (zone_num + 1 >= zinfo->nr_zones)
return -ENOENT;

@@ -884,7 +889,7 @@ static inline bool is_sb_log_zone(struct btrfs_zoned_device_info *zinfo,
if (!zinfo)
return false;

- zone_num = sb_zone_number(zinfo->zone_size_shift, mirror);
+ zone_num = zinfo->sb_zone_location[mirror];
if (zone_num + 1 >= zinfo->nr_zones)
return false;

@@ -1012,7 +1017,7 @@ u64 btrfs_find_allocatable_zones(struct btrfs_device *device, u64 hole_start,
u32 sb_zone;
u64 sb_pos;

- sb_zone = sb_zone_number(shift, i);
+ sb_zone = zinfo->sb_zone_location[i];
if (!(end <= sb_zone ||
sb_zone + BTRFS_NR_SB_LOG_ZONES <= begin)) {
have_sb = true;
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index cbf016a7bb5d..49317524e9a6 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -31,6 +31,7 @@ struct btrfs_zoned_device_info {
unsigned long *active_zones;
struct blk_zone *zone_cache;
struct blk_zone sb_zones[2 * BTRFS_SUPER_MIRROR_MAX];
+ u32 sb_zone_location[BTRFS_SUPER_MIRROR_MAX];
};

#ifdef CONFIG_BLK_DEV_ZONED
--
2.25.1