Re: [PATCH v5 02/28] btrfs: Get zone information of zoned block devices

Anand Jain
2019-12-07T09:48:03Z

On 4/12/19 4:17 PM, Naohiro Aota wrote:
> If a zoned block device is found, get its zone information (number of zones
> and zone size) using the new helper function btrfs_get_dev_zone_info(). To
> avoid costly run-time zone report commands to test the device zones type
> during block allocation, attach the seq_zones bitmap to the device
> structure to indicate if a zone is sequential or accept random writes. Also
> it attaches the empty_zones bitmap to indicate if a zone is empty or not.
>
> This patch also introduces the helper function btrfs_dev_is_sequential() to
> test if the zone storing a block is a sequential write required zone and
> btrfs_dev_is_empty_zone() to test if the zone is a empty zone.
>
> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
> ---
> fs/btrfs/Makefile | 1 +
> fs/btrfs/hmzoned.c | 174 +++++++++++++++++++++++++++++++++++++++++++++
> fs/btrfs/hmzoned.h | 92 ++++++++++++++++++++++++
> fs/btrfs/volumes.c | 18 ++++-
> fs/btrfs/volumes.h | 4 ++
> 5 files changed, 287 insertions(+), 2 deletions(-)
> create mode 100644 fs/btrfs/hmzoned.c
> create mode 100644 fs/btrfs/hmzoned.h
>
> diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
> index 82200dbca5ac..64aaeed397a4 100644
> --- a/fs/btrfs/Makefile
> +++ b/fs/btrfs/Makefile
> @@ -16,6 +16,7 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
> btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o
> btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o
> btrfs-$(CONFIG_BTRFS_FS_REF_VERIFY) += ref-verify.o
> +btrfs-$(CONFIG_BLK_DEV_ZONED) += hmzoned.o
>
> btrfs-$(CONFIG_BTRFS_FS_RUN_SANITY_TESTS) += tests/free-space-tests.o \
> tests/extent-buffer-tests.o tests/btrfs-tests.o \
> diff --git a/fs/btrfs/hmzoned.c b/fs/btrfs/hmzoned.c
> new file mode 100644
> index 000000000000..e37335625f76
> --- /dev/null
> +++ b/fs/btrfs/hmzoned.c
> @@ -0,0 +1,174 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2019 Western Digital Corporation or its affiliates.
> + * Authors:
> + * Naohiro Aota <naohiro.aota@wdc.com>
> + * Damien Le Moal <damien.lemoal@wdc.com>
> + */
> +
> +#include <linux/slab.h>
> +#include <linux/blkdev.h>
> +#include "ctree.h"
> +#include "volumes.h"
> +#include "hmzoned.h"
> +#include "rcu-string.h"
> +
> +/* Maximum number of zones to report per blkdev_report_zones() call */
> +#define BTRFS_REPORT_NR_ZONES 4096
> +
> +static int btrfs_get_dev_zones(struct btrfs_device *device, u64 pos,
> + struct blk_zone *zones, unsigned int *nr_zones)
> +{
> + int ret;
> +
> + ret = blkdev_report_zones(device->bdev, pos >> SECTOR_SHIFT, zones,
> + nr_zones);

Commit d41003513e61 (block: rework zone reporting) has made into the
mainline, which changes the definition of this function and fails to
compile with the mainline.

Thanks, Anand

> + if (ret != 0) {
> + btrfs_err_in_rcu(device->fs_info,
> + "get zone at %llu on %s failed %d", pos,
> + rcu_str_deref(device->name), ret);
> + return ret;
> + }
> + if (!*nr_zones)
> + return -EIO;
> +
> + return 0;
> +}
> +
> +int btrfs_get_dev_zone_info(struct btrfs_device *device)
> +{
> + struct btrfs_zoned_device_info *zone_info = NULL;
> + struct block_device *bdev = device->bdev;
> + sector_t nr_sectors = bdev->bd_part->nr_sects;
> + sector_t sector = 0;
> + struct blk_zone *zones = NULL;
> + unsigned int i, nreported = 0, nr_zones;
> + unsigned int zone_sectors;
> + int ret;
> +#define LEN (sizeof(device->fs_info->sb->s_id) + sizeof("(device )") - 1)
> + char devstr[LEN];
> + const int len = LEN;
> +#undef LEN
> +
> + if (!bdev_is_zoned(bdev))
> + return 0;
> +
> + zone_info = kzalloc(sizeof(*zone_info), GFP_KERNEL);
> + if (!zone_info)
> + return -ENOMEM;
> +
> + zone_sectors = bdev_zone_sectors(bdev);
> + ASSERT(is_power_of_2(zone_sectors));
> + zone_info->zone_size = (u64)zone_sectors << SECTOR_SHIFT;
> + zone_info->zone_size_shift = ilog2(zone_info->zone_size);
> + zone_info->nr_zones = nr_sectors >> ilog2(bdev_zone_sectors(bdev));
> + if (nr_sectors & (bdev_zone_sectors(bdev) - 1))
> + zone_info->nr_zones++;
> +
> + zone_info->seq_zones = kcalloc(BITS_TO_LONGS(zone_info->nr_zones),
> + sizeof(*zone_info->seq_zones),
> + GFP_KERNEL);
> + if (!zone_info->seq_zones) {
> + ret = -ENOMEM;
> + goto free_zone_info;
> + }
> +
> + zone_info->empty_zones = kcalloc(BITS_TO_LONGS(zone_info->nr_zones),
> + sizeof(*zone_info->empty_zones),
> + GFP_KERNEL);
> + if (!zone_info->empty_zones) {
> + ret = -ENOMEM;
> + goto free_seq_zones;
> + }
> +
> + zones = kcalloc(BTRFS_REPORT_NR_ZONES,
> + sizeof(struct blk_zone), GFP_KERNEL);
> + if (!zones) {
> + ret = -ENOMEM;
> + goto free_empty_zones;
> + }
> +
> + /* Get zones type */
> + while (sector < nr_sectors) {
> + nr_zones = BTRFS_REPORT_NR_ZONES;
> + ret = btrfs_get_dev_zones(device, sector << SECTOR_SHIFT, zones,
> + &nr_zones);
> + if (ret)
> + goto free_zones;
> +
> + for (i = 0; i < nr_zones; i++) {
> + if (zones[i].type == BLK_ZONE_TYPE_SEQWRITE_REQ)
> + set_bit(nreported, zone_info->seq_zones);
> + if (zones[i].cond == BLK_ZONE_COND_EMPTY)
> + set_bit(nreported, zone_info->empty_zones);
> + nreported++;
> + }
> + sector = zones[nr_zones - 1].start + zones[nr_zones - 1].len;
> + }
> +
> + if (nreported != zone_info->nr_zones) {
> + btrfs_err_in_rcu(device->fs_info,
> + "inconsistent number of zones on %s (%u / %u)",
> + rcu_str_deref(device->name), nreported,
> + zone_info->nr_zones);
> + ret = -EIO;
> + goto free_zones;
> + }
> +
> + kfree(zones);
> +
> + device->zone_info = zone_info;
> +
> + devstr[0] = 0;
> + if (device->fs_info)
> + snprintf(devstr, len, " (device %s)",
> + device->fs_info->sb->s_id);
> +
> + rcu_read_lock();
> + pr_info(
> +"BTRFS info%s: host-%s zoned block device %s, %u zones of %llu sectors",
> + devstr,
> + bdev_zoned_model(bdev) == BLK_ZONED_HM ? "managed" : "aware",
> + rcu_str_deref(device->name), zone_info->nr_zones,
> + zone_info->zone_size >> SECTOR_SHIFT);
> + rcu_read_unlock();
> +
> + return 0;
> +
> +free_zones:
> + kfree(zones);
> +free_empty_zones:
> + kfree(zone_info->empty_zones);
> +free_seq_zones:
> + kfree(zone_info->seq_zones);
> +free_zone_info:
> + kfree(zone_info);
> +
> + return ret;
> +}
> +
> +void btrfs_destroy_dev_zone_info(struct btrfs_device *device)
> +{
> + struct btrfs_zoned_device_info *zone_info = device->zone_info;
> +
> + if (!zone_info)
> + return;
> +
> + kfree(zone_info->seq_zones);
> + kfree(zone_info->empty_zones);
> + kfree(zone_info);
> + device->zone_info = NULL;
> +}
> +
> +int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
> + struct blk_zone *zone)
> +{
> + unsigned int nr_zones = 1;
> + int ret;
> +
> + ret = btrfs_get_dev_zones(device, pos, zone, &nr_zones);
> + if (ret != 0 || !nr_zones)
> + return ret ? ret : -EIO;
> +
> + return 0;
> +}
> diff --git a/fs/btrfs/hmzoned.h b/fs/btrfs/hmzoned.h
> new file mode 100644
> index 000000000000..0f8006f39aaf
> --- /dev/null
> +++ b/fs/btrfs/hmzoned.h
> @@ -0,0 +1,92 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2019 Western Digital Corporation or its affiliates.
> + * Authors:
> + * Naohiro Aota <naohiro.aota@wdc.com>
> + * Damien Le Moal <damien.lemoal@wdc.com>
> + */
> +
> +#ifndef BTRFS_HMZONED_H
> +#define BTRFS_HMZONED_H
> +
> +struct btrfs_zoned_device_info {
> + /*
> + * Number of zones, zone size and types of zones if bdev is a
> + * zoned block device.
> + */
> + u64 zone_size;
> + u8 zone_size_shift;
> + u32 nr_zones;
> + unsigned long *seq_zones;
> + unsigned long *empty_zones;
> +};
> +
> +#ifdef CONFIG_BLK_DEV_ZONED
> +int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
> + struct blk_zone *zone);
> +int btrfs_get_dev_zone_info(struct btrfs_device *device);
> +void btrfs_destroy_dev_zone_info(struct btrfs_device *device);
> +#else /* CONFIG_BLK_DEV_ZONED */
> +static inline int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
> + struct blk_zone *zone)
> +{
> + return 0;
> +}
> +static inline int btrfs_get_dev_zone_info(struct btrfs_device *device)
> +{
> + return 0;
> +}
> +static inline void btrfs_destroy_dev_zone_info(struct btrfs_device *device) { }
> +#endif
> +
> +static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)
> +{
> + struct btrfs_zoned_device_info *zone_info = device->zone_info;
> +
> + if (!zone_info)
> + return false;
> +
> + return test_bit(pos >> zone_info->zone_size_shift,
> + zone_info->seq_zones);
> +}
> +
> +static inline bool btrfs_dev_is_empty_zone(struct btrfs_device *device, u64 pos)
> +{
> + struct btrfs_zoned_device_info *zone_info = device->zone_info;
> +
> + if (!zone_info)
> + return true;
> +
> + return test_bit(pos >> zone_info->zone_size_shift,
> + zone_info->empty_zones);
> +}
> +
> +static inline void btrfs_dev_set_empty_zone_bit(struct btrfs_device *device,
> + u64 pos, bool set)
> +{
> + struct btrfs_zoned_device_info *zone_info = device->zone_info;
> + unsigned int zno;
> +
> + if (!zone_info)
> + return;
> +
> + zno = pos >> zone_info->zone_size_shift;
> + if (set)
> + set_bit(zno, zone_info->empty_zones);
> + else
> + clear_bit(zno, zone_info->empty_zones);
> +}
> +
> +static inline void btrfs_dev_set_zone_empty(struct btrfs_device *device,
> + u64 pos)
> +{
> + btrfs_dev_set_empty_zone_bit(device, pos, true);
> +}
> +
> +static inline void btrfs_dev_clear_zone_empty(struct btrfs_device *device,
> + u64 pos)
> +{
> + btrfs_dev_set_empty_zone_bit(device, pos, false);
> +}
> +
> +#endif
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index d8e5560db285..18ea8dfce244 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -30,6 +30,7 @@
> #include "tree-checker.h"
> #include "space-info.h"
> #include "block-group.h"
> +#include "hmzoned.h"
>
> const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
> [BTRFS_RAID_RAID10] = {
> @@ -366,6 +367,7 @@ void btrfs_free_device(struct btrfs_device *device)
> rcu_string_free(device->name);
> extent_io_tree_release(&device->alloc_state);
> bio_put(device->flush_bio);
> + btrfs_destroy_dev_zone_info(device);
> kfree(device);
> }
>
> @@ -650,6 +652,11 @@ static int btrfs_open_one_device(struct btrfs_fs_devices *fs_devices,
> clear_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state);
> device->mode = flags;
>
> + /* Get zone type information of zoned block devices */
> + ret = btrfs_get_dev_zone_info(device);
> + if (ret != 0)
> + goto error_brelse;
> +
> fs_devices->open_devices++;
> if (test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state) &&
> device->devid != BTRFS_DEV_REPLACE_DEVID) {
> @@ -2421,6 +2428,14 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
> }
> rcu_assign_pointer(device->name, name);
>
> + device->fs_info = fs_info;
> + device->bdev = bdev;
> +
> + /* Get zone type information of zoned block devices */
> + ret = btrfs_get_dev_zone_info(device);
> + if (ret)
> + goto error_free_device;
> +
> trans = btrfs_start_transaction(root, 0);
> if (IS_ERR(trans)) {
> ret = PTR_ERR(trans);
> @@ -2437,8 +2452,6 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
> fs_info->sectorsize);
> device->disk_total_bytes = device->total_bytes;
> device->commit_total_bytes = device->total_bytes;
> - device->fs_info = fs_info;
> - device->bdev = bdev;
> set_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state);
> clear_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state);
> device->mode = FMODE_EXCL;
> @@ -2571,6 +2584,7 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
> sb->s_flags |= SB_RDONLY;
> if (trans)
> btrfs_end_transaction(trans);
> + btrfs_destroy_dev_zone_info(device);
> error_free_device:
> btrfs_free_device(device);
> error:
> diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
> index fc1b564b9cfe..70cabe65f72a 100644
> --- a/fs/btrfs/volumes.h
> +++ b/fs/btrfs/volumes.h
> @@ -53,6 +53,8 @@ struct btrfs_io_geometry {
> #define BTRFS_DEV_STATE_REPLACE_TGT (3)
> #define BTRFS_DEV_STATE_FLUSH_SENT (4)
>
> +struct btrfs_zoned_device_info;
> +
> struct btrfs_device {
> struct list_head dev_list; /* device_list_mutex */
> struct list_head dev_alloc_list; /* chunk mutex */
> @@ -66,6 +68,8 @@ struct btrfs_device {
>
> struct block_device *bdev;
>
> + struct btrfs_zoned_device_info *zone_info;
> +
> /* the mode sent to blkdev_get */
> fmode_t mode;
>
>