commit 16beac87e95e2fb278b552397c8260637f8a63f7 upstream.

When mounting a device, we are reporting the zones twice: once for checking the zone attributes in btrfs_get_dev_zone_info and once for loading block groups' zone info in btrfs_load_block_group_zone_info(). With a lot of block groups, that leads to a lot of REPORT ZONE commands and slows down the mount process.

This patch introduces a zone info cache in struct btrfs_zoned_device_info. The cache is populated while in btrfs_get_dev_zone_info() and used for btrfs_load_block_group_zone_info() to reduce the number of REPORT ZONE commands. The zone cache is then released after loading the block groups, as it will not be much effective during the run time.

Benchmark: Mount an HDD with 57,007 block groups Before patch: 171.368 seconds After patch: 64.064 seconds

While it still takes a minute due to the slowness of loading all the block groups, the patch reduces the mount time by 1/3.

Link: https://lore.kernel.org/linux-btrfs/CAHQ7scUiLtcTqZOMMY5kbWUBOhGRwKo6J6wYPT5... Fixes: 5b316468983d ("btrfs: get zone information of zoned block devices") CC: stable@vger.kernel.org Signed-off-by: Naohiro Aota naohiro.aota@wdc.com Signed-off-by: David Sterba dsterba@suse.com --- fs/btrfs/dev-replace.c | 2 +- fs/btrfs/disk-io.c | 2 + fs/btrfs/volumes.c | 2 +- fs/btrfs/zoned.c | 85 ++++++++++++++++++++++++++++++++++++++---- fs/btrfs/zoned.h | 8 +++- 5 files changed, 87 insertions(+), 12 deletions(-)

diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c index d029be40ea6f..bdbc310a8f8c 100644 --- a/fs/btrfs/dev-replace.c +++ b/fs/btrfs/dev-replace.c @@ -325,7 +325,7 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info, set_blocksize(device->bdev, BTRFS_BDEV_BLOCKSIZE); device->fs_devices = fs_info->fs_devices;

- ret = btrfs_get_dev_zone_info(device); + ret = btrfs_get_dev_zone_info(device, false); if (ret) goto error;

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index e1a262120e02..2c3e106a0270 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -3565,6 +3565,8 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device goto fail_sysfs; }

+ btrfs_free_zone_cache(fs_info); + if (!sb_rdonly(sb) && fs_info->fs_devices->missing_devices && !btrfs_check_rw_degradable(fs_info, NULL)) { btrfs_warn(fs_info, diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index c34efdc1ecdd..06a1a7c2254c 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -2596,7 +2596,7 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path device->fs_info = fs_info; device->bdev = bdev;

- ret = btrfs_get_dev_zone_info(device); + ret = btrfs_get_dev_zone_info(device, false); if (ret) goto error_free_device;

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c index 5672c24a2d58..596b2148807d 100644 --- a/fs/btrfs/zoned.c +++ b/fs/btrfs/zoned.c @@ -4,6 +4,7 @@ #include <linux/slab.h> #include <linux/blkdev.h> #include <linux/sched/mm.h> +#include <linux/vmalloc.h> #include "ctree.h" #include "volumes.h" #include "zoned.h" @@ -195,6 +196,8 @@ static int emulate_report_zones(struct btrfs_device *device, u64 pos, static int btrfs_get_dev_zones(struct btrfs_device *device, u64 pos, struct blk_zone *zones, unsigned int *nr_zones) { + struct btrfs_zoned_device_info *zinfo = device->zone_info; + u32 zno; int ret;

if (!*nr_zones) @@ -206,6 +209,34 @@ static int btrfs_get_dev_zones(struct btrfs_device *device, u64 pos, return 0; }

+ /* Check cache */ + if (zinfo->zone_cache) { + unsigned int i; + + ASSERT(IS_ALIGNED(pos, zinfo->zone_size)); + zno = pos >> zinfo->zone_size_shift; + /* + * We cannot report zones beyond the zone end. So, it is OK to + * cap *nr_zones to at the end. + */ + *nr_zones = min_t(u32, *nr_zones, zinfo->nr_zones - zno); + + for (i = 0; i < *nr_zones; i++) { + struct blk_zone *zone_info; + + zone_info = &zinfo->zone_cache[zno + i]; + if (!zone_info->len) + break; + } + + if (i == *nr_zones) { + /* Cache hit on all the zones */ + memcpy(zones, zinfo->zone_cache + zno, + sizeof(*zinfo->zone_cache) * *nr_zones); + return 0; + } + } + ret = blkdev_report_zones(device->bdev, pos >> SECTOR_SHIFT, *nr_zones, copy_zone_info_cb, zones); if (ret < 0) { @@ -219,6 +250,11 @@ static int btrfs_get_dev_zones(struct btrfs_device *device, u64 pos, if (!ret) return -EIO;

+ /* Populate cache */ + if (zinfo->zone_cache) + memcpy(zinfo->zone_cache + zno, zones, + sizeof(*zinfo->zone_cache) * *nr_zones); + return 0; }

@@ -282,7 +318,7 @@ int btrfs_get_dev_zone_info_all_devices(struct btrfs_fs_info *fs_info) if (!device->bdev) continue;

- ret = btrfs_get_dev_zone_info(device); + ret = btrfs_get_dev_zone_info(device, true); if (ret) break; } @@ -291,7 +327,7 @@ int btrfs_get_dev_zone_info_all_devices(struct btrfs_fs_info *fs_info) return ret; }

-int btrfs_get_dev_zone_info(struct btrfs_device *device) +int btrfs_get_dev_zone_info(struct btrfs_device *device, bool populate_cache) { struct btrfs_fs_info *fs_info = device->fs_info; struct btrfs_zoned_device_info *zone_info = NULL; @@ -318,6 +354,8 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device) if (!zone_info) return -ENOMEM;

+ device->zone_info = zone_info; + if (!bdev_is_zoned(bdev)) { if (!fs_info->zone_size) { ret = calculate_emulated_zone_size(fs_info); @@ -369,6 +407,23 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device) goto out; }

+ /* + * Enable zone cache only for a zoned device. On a non-zoned device, we + * fill the zone info with emulated CONVENTIONAL zones, so no need to + * use the cache. + */ + if (populate_cache && bdev_is_zoned(device->bdev)) { + zone_info->zone_cache = vzalloc(sizeof(struct blk_zone) * + zone_info->nr_zones); + if (!zone_info->zone_cache) { + btrfs_err_in_rcu(device->fs_info, + "zoned: failed to allocate zone cache for %s", + rcu_str_deref(device->name)); + ret = -ENOMEM; + goto out; + } + } + /* Get zones type */ while (sector < nr_sectors) { nr_zones = BTRFS_REPORT_NR_ZONES; @@ -444,8 +499,6 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device)

kfree(zones);

- device->zone_info = zone_info; - switch (bdev_zoned_model(bdev)) { case BLK_ZONED_HM: model = "host-managed zoned"; @@ -478,10 +531,7 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device) out: kfree(zones); out_free_zone_info: - bitmap_free(zone_info->empty_zones); - bitmap_free(zone_info->seq_zones); - kfree(zone_info); - device->zone_info = NULL; + btrfs_destroy_dev_zone_info(device);

return ret; } @@ -495,6 +545,7 @@ void btrfs_destroy_dev_zone_info(struct btrfs_device *device)

bitmap_free(zone_info->seq_zones); bitmap_free(zone_info->empty_zones); + vfree(zone_info->zone_cache); kfree(zone_info); device->zone_info = NULL; } @@ -1551,3 +1602,21 @@ void btrfs_clear_data_reloc_bg(struct btrfs_block_group *bg) fs_info->data_reloc_bg = 0; spin_unlock(&fs_info->relocation_bg_lock); } + +void btrfs_free_zone_cache(struct btrfs_fs_info *fs_info) +{ + struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; + struct btrfs_device *device; + + if (!btrfs_is_zoned(fs_info)) + return; + + mutex_lock(&fs_devices->device_list_mutex); + list_for_each_entry(device, &fs_devices->devices, dev_list) { + if (device->zone_info) { + vfree(device->zone_info->zone_cache); + device->zone_info->zone_cache = NULL; + } + } + mutex_unlock(&fs_devices->device_list_mutex); +} diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h index 70b3be517599..813aa3cddc11 100644 --- a/fs/btrfs/zoned.h +++ b/fs/btrfs/zoned.h @@ -25,6 +25,7 @@ struct btrfs_zoned_device_info { u32 nr_zones; unsigned long *seq_zones; unsigned long *empty_zones; + struct blk_zone *zone_cache; struct blk_zone sb_zones[2 * BTRFS_SUPER_MIRROR_MAX]; };

@@ -32,7 +33,7 @@ struct btrfs_zoned_device_info { int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos, struct blk_zone *zone); int btrfs_get_dev_zone_info_all_devices(struct btrfs_fs_info *fs_info); -int btrfs_get_dev_zone_info(struct btrfs_device *device); +int btrfs_get_dev_zone_info(struct btrfs_device *device, bool populate_cache); void btrfs_destroy_dev_zone_info(struct btrfs_device *device); int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info); int btrfs_check_mountopts_zoned(struct btrfs_fs_info *info); @@ -67,6 +68,7 @@ int btrfs_sync_zone_write_pointer(struct btrfs_device *tgt_dev, u64 logical, struct btrfs_device *btrfs_zoned_get_device(struct btrfs_fs_info *fs_info, u64 logical, u64 length); void btrfs_clear_data_reloc_bg(struct btrfs_block_group *bg); +void btrfs_free_zone_cache(struct btrfs_fs_info *fs_info); #else /* CONFIG_BLK_DEV_ZONED */ static inline int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos, struct blk_zone *zone) @@ -79,7 +81,8 @@ static inline int btrfs_get_dev_zone_info_all_devices(struct btrfs_fs_info *fs_i return 0; }

-static inline int btrfs_get_dev_zone_info(struct btrfs_device *device) +static inline int btrfs_get_dev_zone_info(struct btrfs_device *device, + bool populate_cache) { return 0; } @@ -202,6 +205,7 @@ static inline struct btrfs_device *btrfs_zoned_get_device(

static inline void btrfs_clear_data_reloc_bg(struct btrfs_block_group *bg) { }

+static inline void btrfs_free_zone_cache(struct btrfs_fs_info *fs_info) { } #endif

static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)