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

Naohiro Aota
2019-12-10T04:42:00Z

On Sat, Dec 07, 2019 at 05:47:35PM +0800, Anand Jain wrote:
>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.

Yes, I'm aware of the blk-zoned API change. This patch series is based
on kdave/for-5.5 which is basing on v5.4-rc8, thus the basing branch
does not contain the block layer commits yet. I will add a patch to
follow the API change in the next version of my patch series.

Thanks,

>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;
>>
>