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

Naohiro Aota
2019-12-04T08:19:32Z

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);
+ 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;

--
2.24.0