[v3,02/27] btrfs: Get zone information of zoned block devices
diff mbox series

Message ID 20190808093038.4163421-3-naohiro.aota@wdc.com
State New
Headers show
Series
  • btrfs zoned block device support
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Commit Message

Naohiro Aota Aug. 8, 2019, 9:30 a.m. UTC
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_zonetypes().  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  |   2 +-
 fs/btrfs/hmzoned.c | 162 +++++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/hmzoned.h |  79 ++++++++++++++++++++++
 fs/btrfs/volumes.c |  18 ++++-
 fs/btrfs/volumes.h |   4 ++
 5 files changed, 262 insertions(+), 3 deletions(-)
 create mode 100644 fs/btrfs/hmzoned.c
 create mode 100644 fs/btrfs/hmzoned.h

Comments

Anand Jain Aug. 16, 2019, 4:44 a.m. UTC | #1
On 8/8/19 5:30 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_zonetypes().  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  |   2 +-
>   fs/btrfs/hmzoned.c | 162 +++++++++++++++++++++++++++++++++++++++++++++
>   fs/btrfs/hmzoned.h |  79 ++++++++++++++++++++++
>   fs/btrfs/volumes.c |  18 ++++-
>   fs/btrfs/volumes.h |   4 ++
>   5 files changed, 262 insertions(+), 3 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 76a843198bcb..8d93abb31074 100644
> --- a/fs/btrfs/Makefile
> +++ b/fs/btrfs/Makefile
> @@ -11,7 +11,7 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
>   	   compression.o delayed-ref.o relocation.o delayed-inode.o scrub.o \
>   	   reada.o backref.o ulist.o qgroup.o send.o dev-replace.o raid56.o \
>   	   uuid-tree.o props.o free-space-tree.o tree-checker.o space-info.o \
> -	   block-rsv.o delalloc-space.o
> +	   block-rsv.o delalloc-space.o hmzoned.o
>   
>   btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o
>   btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o
> diff --git a/fs/btrfs/hmzoned.c b/fs/btrfs/hmzoned.c
> new file mode 100644
> index 000000000000..bfd04792dd62
> --- /dev/null
> +++ b/fs/btrfs/hmzoned.c
> @@ -0,0 +1,162 @@
> +// 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_ret,
> +			       unsigned int *nr_zones, gfp_t gfp_mask)
> +{
> +	struct blk_zone *zones = *zones_ret;
> +	int ret;
> +
> +	if (!zones) {
> +		zones = kcalloc(*nr_zones, sizeof(struct blk_zone), GFP_KERNEL);
> +		if (!zones)
> +			return -ENOMEM;
> +	}
> +
> +	ret = blkdev_report_zones(device->bdev, pos >> SECTOR_SHIFT,
> +				  zones, nr_zones, gfp_mask);
> +	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;
> +
> +	*zones_ret = zones;
> +
> +	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;
> +
> +	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 out;
> +	}
> +
> +	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 out;
> +	}
> +
> +	/* 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, GFP_KERNEL);


How many zones do we see in a disk? Not many I presume.
Here the allocation for %zones is inconsistent for each zone, unless
there is substantial performance benefits, a consistent flow of
alloc/free is fine as it makes the code easy to read and verify.


Thanks, Anand

> +		if (ret)
> +			goto out;
> +
> +		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 out;
> +	}
> +
> +	device->zone_info = zone_info;
> +
> +	btrfs_info_in_rcu(
> +		device->fs_info,
> +		"host-%s zoned block device %s, %u zones of %llu sectors",
> +		bdev_zoned_model(bdev) == BLK_ZONED_HM ? "managed" : "aware",
> +		rcu_str_deref(device->name), zone_info->nr_zones,
> +		zone_info->zone_size >> SECTOR_SHIFT);
> +
> +out:
> +	kfree(zones);
> +
> +	if (ret) {
> +		kfree(zone_info->seq_zones);
> +		kfree(zone_info->empty_zones);
> +		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, gfp_t gfp_mask)
> +{
> +	unsigned int nr_zones = 1;
> +	int ret;
> +
> +	ret = btrfs_get_dev_zones(device, pos, &zone, &nr_zones, gfp_mask);
> +	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..ffc70842135e
> --- /dev/null
> +++ b/fs/btrfs/hmzoned.h
> @@ -0,0 +1,79 @@
> +/* 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;
> +};
> +
> +int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
> +		       struct blk_zone *zone, gfp_t gfp_mask);
> +int btrfs_get_dev_zone_info(struct btrfs_device *device);
> +void btrfs_destroy_dev_zone_info(struct btrfs_device *device);
> +
> +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 d74b74ca07af..8e5a894e7bde 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -29,6 +29,7 @@
>   #include "sysfs.h"
>   #include "tree-checker.h"
>   #include "space-info.h"
> +#include "hmzoned.h"
>   
>   const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
>   	[BTRFS_RAID_RAID10] = {
> @@ -342,6 +343,7 @@ 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);
>   }
>   
> @@ -847,6 +849,11 @@ 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) {
> @@ -2598,6 +2605,14 @@ 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);
> @@ -2614,8 +2629,6 @@ 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;
> @@ -2756,6 +2769,7 @@ 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 7f6aa1816409..5da1f354db93 100644
> --- a/fs/btrfs/volumes.h
> +++ b/fs/btrfs/volumes.h
> @@ -57,6 +57,8 @@ 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 */
> @@ -77,6 +79,8 @@ struct btrfs_device {
>   
>   	struct block_device *bdev;
>   
> +	struct btrfs_zoned_device_info *zone_info;
> +
>   	/* the mode sent to blkdev_get */
>   	fmode_t mode;
>   
>
Damien Le Moal Aug. 16, 2019, 2:19 p.m. UTC | #2
On 2019/08/15 21:47, Anand Jain wrote:
> On 8/8/19 5:30 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_zonetypes().  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  |   2 +-
>>   fs/btrfs/hmzoned.c | 162 +++++++++++++++++++++++++++++++++++++++++++++
>>   fs/btrfs/hmzoned.h |  79 ++++++++++++++++++++++
>>   fs/btrfs/volumes.c |  18 ++++-
>>   fs/btrfs/volumes.h |   4 ++
>>   5 files changed, 262 insertions(+), 3 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 76a843198bcb..8d93abb31074 100644
>> --- a/fs/btrfs/Makefile
>> +++ b/fs/btrfs/Makefile
>> @@ -11,7 +11,7 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
>>   	   compression.o delayed-ref.o relocation.o delayed-inode.o scrub.o \
>>   	   reada.o backref.o ulist.o qgroup.o send.o dev-replace.o raid56.o \
>>   	   uuid-tree.o props.o free-space-tree.o tree-checker.o space-info.o \
>> -	   block-rsv.o delalloc-space.o
>> +	   block-rsv.o delalloc-space.o hmzoned.o
>>   
>>   btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o
>>   btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o
>> diff --git a/fs/btrfs/hmzoned.c b/fs/btrfs/hmzoned.c
>> new file mode 100644
>> index 000000000000..bfd04792dd62
>> --- /dev/null
>> +++ b/fs/btrfs/hmzoned.c
>> @@ -0,0 +1,162 @@
>> +// 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_ret,
>> +			       unsigned int *nr_zones, gfp_t gfp_mask)
>> +{
>> +	struct blk_zone *zones = *zones_ret;
>> +	int ret;
>> +
>> +	if (!zones) {
>> +		zones = kcalloc(*nr_zones, sizeof(struct blk_zone), GFP_KERNEL);
>> +		if (!zones)
>> +			return -ENOMEM;
>> +	}
>> +
>> +	ret = blkdev_report_zones(device->bdev, pos >> SECTOR_SHIFT,
>> +				  zones, nr_zones, gfp_mask);
>> +	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;
>> +
>> +	*zones_ret = zones;
>> +
>> +	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;
>> +
>> +	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 out;
>> +	}
>> +
>> +	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 out;
>> +	}
>> +
>> +	/* 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, GFP_KERNEL);
> 
> 
> How many zones do we see in a disk? Not many I presume.

A 15 TB SMR drive with 256 MB zones (which is a failry common value for products
out there) has over 55,000 zones. "Not many" is subjective... I personally
consider 55000 a large number and that one should take care to write appropriate
code to manage that many objects.

> Here the allocation for %zones is inconsistent for each zone, unless
> there is substantial performance benefits, a consistent flow of
> alloc/free is fine as it makes the code easy to read and verify.

I do not understand your comment here. btrfs_get_dev_zones() will allocate and
fill the zones array with at most BTRFS_REPORT_NR_ZONES zones descriptors on the
first call. On subsequent calls, the same array is reused until information on
all zones of the disk is obtained. "the allocation for %zones is inconsistent
for each zone" does not makes much sense. What exactly do you mean ?

> 
> 
> Thanks, Anand
> 
>> +		if (ret)
>> +			goto out;
>> +
>> +		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 out;
>> +	}
>> +
>> +	device->zone_info = zone_info;
>> +
>> +	btrfs_info_in_rcu(
>> +		device->fs_info,
>> +		"host-%s zoned block device %s, %u zones of %llu sectors",
>> +		bdev_zoned_model(bdev) == BLK_ZONED_HM ? "managed" : "aware",
>> +		rcu_str_deref(device->name), zone_info->nr_zones,
>> +		zone_info->zone_size >> SECTOR_SHIFT);
>> +
>> +out:
>> +	kfree(zones);
>> +
>> +	if (ret) {
>> +		kfree(zone_info->seq_zones);
>> +		kfree(zone_info->empty_zones);
>> +		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, gfp_t gfp_mask)
>> +{
>> +	unsigned int nr_zones = 1;
>> +	int ret;
>> +
>> +	ret = btrfs_get_dev_zones(device, pos, &zone, &nr_zones, gfp_mask);
>> +	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..ffc70842135e
>> --- /dev/null
>> +++ b/fs/btrfs/hmzoned.h
>> @@ -0,0 +1,79 @@
>> +/* 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;
>> +};
>> +
>> +int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
>> +		       struct blk_zone *zone, gfp_t gfp_mask);
>> +int btrfs_get_dev_zone_info(struct btrfs_device *device);
>> +void btrfs_destroy_dev_zone_info(struct btrfs_device *device);
>> +
>> +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 d74b74ca07af..8e5a894e7bde 100644
>> --- a/fs/btrfs/volumes.c
>> +++ b/fs/btrfs/volumes.c
>> @@ -29,6 +29,7 @@
>>   #include "sysfs.h"
>>   #include "tree-checker.h"
>>   #include "space-info.h"
>> +#include "hmzoned.h"
>>   
>>   const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
>>   	[BTRFS_RAID_RAID10] = {
>> @@ -342,6 +343,7 @@ 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);
>>   }
>>   
>> @@ -847,6 +849,11 @@ 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) {
>> @@ -2598,6 +2605,14 @@ 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);
>> @@ -2614,8 +2629,6 @@ 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;
>> @@ -2756,6 +2769,7 @@ 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 7f6aa1816409..5da1f354db93 100644
>> --- a/fs/btrfs/volumes.h
>> +++ b/fs/btrfs/volumes.h
>> @@ -57,6 +57,8 @@ 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 */
>> @@ -77,6 +79,8 @@ struct btrfs_device {
>>   
>>   	struct block_device *bdev;
>>   
>> +	struct btrfs_zoned_device_info *zone_info;
>> +
>>   	/* the mode sent to blkdev_get */
>>   	fmode_t mode;
>>   
>>
> 
>
Anand Jain Aug. 16, 2019, 11:47 p.m. UTC | #3
On 8/16/19 10:19 PM, Damien Le Moal wrote:
> On 2019/08/15 21:47, Anand Jain wrote:
>> On 8/8/19 5:30 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_zonetypes().  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  |   2 +-
>>>    fs/btrfs/hmzoned.c | 162 +++++++++++++++++++++++++++++++++++++++++++++
>>>    fs/btrfs/hmzoned.h |  79 ++++++++++++++++++++++
>>>    fs/btrfs/volumes.c |  18 ++++-
>>>    fs/btrfs/volumes.h |   4 ++
>>>    5 files changed, 262 insertions(+), 3 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 76a843198bcb..8d93abb31074 100644
>>> --- a/fs/btrfs/Makefile
>>> +++ b/fs/btrfs/Makefile
>>> @@ -11,7 +11,7 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
>>>    	   compression.o delayed-ref.o relocation.o delayed-inode.o scrub.o \
>>>    	   reada.o backref.o ulist.o qgroup.o send.o dev-replace.o raid56.o \
>>>    	   uuid-tree.o props.o free-space-tree.o tree-checker.o space-info.o \
>>> -	   block-rsv.o delalloc-space.o
>>> +	   block-rsv.o delalloc-space.o hmzoned.o
>>>    
>>>    btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o
>>>    btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o
>>> diff --git a/fs/btrfs/hmzoned.c b/fs/btrfs/hmzoned.c
>>> new file mode 100644
>>> index 000000000000..bfd04792dd62
>>> --- /dev/null
>>> +++ b/fs/btrfs/hmzoned.c
>>> @@ -0,0 +1,162 @@
>>> +// 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_ret,
>>> +			       unsigned int *nr_zones, gfp_t gfp_mask)
>>> +{
>>> +	struct blk_zone *zones = *zones_ret;
>>> +	int ret;
>>> +
>>> +	if (!zones) {
>>> +		zones = kcalloc(*nr_zones, sizeof(struct blk_zone), GFP_KERNEL);
>>> +		if (!zones)
>>> +			return -ENOMEM;
>>> +	}
>>> +
>>> +	ret = blkdev_report_zones(device->bdev, pos >> SECTOR_SHIFT,
>>> +				  zones, nr_zones, gfp_mask);
>>> +	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;
>>> +
>>> +	*zones_ret = zones;
>>> +
>>> +	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;
>>> +
>>> +	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 out;
>>> +	}
>>> +
>>> +	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 out;
>>> +	}
>>> +
>>> +	/* 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, GFP_KERNEL);
>>
>>
>> How many zones do we see in a disk? Not many I presume.
> 
> A 15 TB SMR drive with 256 MB zones (which is a failry common value for products
> out there) has over 55,000 zones. "Not many" is subjective... I personally
> consider 55000 a large number and that one should take care to write appropriate
> code to manage that many objects.

  Agree that's pretty large.

>> Here the allocation for %zones is inconsistent for each zone, unless
>> there is substantial performance benefits, a consistent flow of
>> alloc/free is fine as it makes the code easy to read and verify.
> 
> I do not understand your comment here. btrfs_get_dev_zones() will allocate and
> fill the zones array with at most BTRFS_REPORT_NR_ZONES zones descriptors on the
> first call. On subsequent calls, the same array is reused until information on
> all zones of the disk is obtained. "the allocation for %zones is inconsistent
> for each zone" does not makes much sense. What exactly do you mean ?

  btrfs_get_dev_zones() allocates the memory for %zones_ret, and expects
  its parent function btrfs_get_dev_zone_info() to free, instead can we
  have alloc and free in the parent function btrfs_get_dev_zone_info().

Thanks, Anand

>>
>>
>> Thanks, Anand
>>
>>> +		if (ret)
>>> +			goto out;
>>> +
>>> +		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 out;
>>> +	}
>>> +
>>> +	device->zone_info = zone_info;
>>> +
>>> +	btrfs_info_in_rcu(
>>> +		device->fs_info,
>>> +		"host-%s zoned block device %s, %u zones of %llu sectors",
>>> +		bdev_zoned_model(bdev) == BLK_ZONED_HM ? "managed" : "aware",
>>> +		rcu_str_deref(device->name), zone_info->nr_zones,
>>> +		zone_info->zone_size >> SECTOR_SHIFT);
>>> +
>>> +out:
>>> +	kfree(zones);
>>> +
>>> +	if (ret) {
>>> +		kfree(zone_info->seq_zones);
>>> +		kfree(zone_info->empty_zones);
>>> +		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, gfp_t gfp_mask)
>>> +{
>>> +	unsigned int nr_zones = 1;
>>> +	int ret;
>>> +
>>> +	ret = btrfs_get_dev_zones(device, pos, &zone, &nr_zones, gfp_mask);
>>> +	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..ffc70842135e
>>> --- /dev/null
>>> +++ b/fs/btrfs/hmzoned.h
>>> @@ -0,0 +1,79 @@
>>> +/* 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;
>>> +};
>>> +
>>> +int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
>>> +		       struct blk_zone *zone, gfp_t gfp_mask);
>>> +int btrfs_get_dev_zone_info(struct btrfs_device *device);
>>> +void btrfs_destroy_dev_zone_info(struct btrfs_device *device);
>>> +
>>> +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 d74b74ca07af..8e5a894e7bde 100644
>>> --- a/fs/btrfs/volumes.c
>>> +++ b/fs/btrfs/volumes.c
>>> @@ -29,6 +29,7 @@
>>>    #include "sysfs.h"
>>>    #include "tree-checker.h"
>>>    #include "space-info.h"
>>> +#include "hmzoned.h"
>>>    
>>>    const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
>>>    	[BTRFS_RAID_RAID10] = {
>>> @@ -342,6 +343,7 @@ 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);
>>>    }
>>>    
>>> @@ -847,6 +849,11 @@ 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) {
>>> @@ -2598,6 +2605,14 @@ 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);
>>> @@ -2614,8 +2629,6 @@ 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;
>>> @@ -2756,6 +2769,7 @@ 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 7f6aa1816409..5da1f354db93 100644
>>> --- a/fs/btrfs/volumes.h
>>> +++ b/fs/btrfs/volumes.h
>>> @@ -57,6 +57,8 @@ 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 */
>>> @@ -77,6 +79,8 @@ struct btrfs_device {
>>>    
>>>    	struct block_device *bdev;
>>>    
>>> +	struct btrfs_zoned_device_info *zone_info;
>>> +
>>>    	/* the mode sent to blkdev_get */
>>>    	fmode_t mode;
>>>    
>>>
>>
>>
> 
>
Damien Le Moal Aug. 16, 2019, 11:55 p.m. UTC | #4
On 2019/08/16 16:48, Anand Jain wrote:
[...]
>>> How many zones do we see in a disk? Not many I presume.
>>
>> A 15 TB SMR drive with 256 MB zones (which is a failry common value for products
>> out there) has over 55,000 zones. "Not many" is subjective... I personally
>> consider 55000 a large number and that one should take care to write appropriate
>> code to manage that many objects.
> 
>   Agree that's pretty large.
> 
>>> Here the allocation for %zones is inconsistent for each zone, unless
>>> there is substantial performance benefits, a consistent flow of
>>> alloc/free is fine as it makes the code easy to read and verify.
>>
>> I do not understand your comment here. btrfs_get_dev_zones() will allocate and
>> fill the zones array with at most BTRFS_REPORT_NR_ZONES zones descriptors on the
>> first call. On subsequent calls, the same array is reused until information on
>> all zones of the disk is obtained. "the allocation for %zones is inconsistent
>> for each zone" does not makes much sense. What exactly do you mean ?
> 
>   btrfs_get_dev_zones() allocates the memory for %zones_ret, and expects
>   its parent function btrfs_get_dev_zone_info() to free, instead can we
>   have alloc and free in the parent function btrfs_get_dev_zone_info().

Got it. Yes, we can change that. Thanks.

> 
> Thanks, Anand

Patch
diff mbox series

diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index 76a843198bcb..8d93abb31074 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -11,7 +11,7 @@  btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
 	   compression.o delayed-ref.o relocation.o delayed-inode.o scrub.o \
 	   reada.o backref.o ulist.o qgroup.o send.o dev-replace.o raid56.o \
 	   uuid-tree.o props.o free-space-tree.o tree-checker.o space-info.o \
-	   block-rsv.o delalloc-space.o
+	   block-rsv.o delalloc-space.o hmzoned.o
 
 btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o
 btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o
diff --git a/fs/btrfs/hmzoned.c b/fs/btrfs/hmzoned.c
new file mode 100644
index 000000000000..bfd04792dd62
--- /dev/null
+++ b/fs/btrfs/hmzoned.c
@@ -0,0 +1,162 @@ 
+// 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_ret,
+			       unsigned int *nr_zones, gfp_t gfp_mask)
+{
+	struct blk_zone *zones = *zones_ret;
+	int ret;
+
+	if (!zones) {
+		zones = kcalloc(*nr_zones, sizeof(struct blk_zone), GFP_KERNEL);
+		if (!zones)
+			return -ENOMEM;
+	}
+
+	ret = blkdev_report_zones(device->bdev, pos >> SECTOR_SHIFT,
+				  zones, nr_zones, gfp_mask);
+	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;
+
+	*zones_ret = zones;
+
+	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;
+
+	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 out;
+	}
+
+	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 out;
+	}
+
+	/* 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, GFP_KERNEL);
+		if (ret)
+			goto out;
+
+		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 out;
+	}
+
+	device->zone_info = zone_info;
+
+	btrfs_info_in_rcu(
+		device->fs_info,
+		"host-%s zoned block device %s, %u zones of %llu sectors",
+		bdev_zoned_model(bdev) == BLK_ZONED_HM ? "managed" : "aware",
+		rcu_str_deref(device->name), zone_info->nr_zones,
+		zone_info->zone_size >> SECTOR_SHIFT);
+
+out:
+	kfree(zones);
+
+	if (ret) {
+		kfree(zone_info->seq_zones);
+		kfree(zone_info->empty_zones);
+		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, gfp_t gfp_mask)
+{
+	unsigned int nr_zones = 1;
+	int ret;
+
+	ret = btrfs_get_dev_zones(device, pos, &zone, &nr_zones, gfp_mask);
+	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..ffc70842135e
--- /dev/null
+++ b/fs/btrfs/hmzoned.h
@@ -0,0 +1,79 @@ 
+/* 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;
+};
+
+int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
+		       struct blk_zone *zone, gfp_t gfp_mask);
+int btrfs_get_dev_zone_info(struct btrfs_device *device);
+void btrfs_destroy_dev_zone_info(struct btrfs_device *device);
+
+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 d74b74ca07af..8e5a894e7bde 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -29,6 +29,7 @@ 
 #include "sysfs.h"
 #include "tree-checker.h"
 #include "space-info.h"
+#include "hmzoned.h"
 
 const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
 	[BTRFS_RAID_RAID10] = {
@@ -342,6 +343,7 @@  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);
 }
 
@@ -847,6 +849,11 @@  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) {
@@ -2598,6 +2605,14 @@  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);
@@ -2614,8 +2629,6 @@  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;
@@ -2756,6 +2769,7 @@  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 7f6aa1816409..5da1f354db93 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -57,6 +57,8 @@  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 */
@@ -77,6 +79,8 @@  struct btrfs_device {
 
 	struct block_device *bdev;
 
+	struct btrfs_zoned_device_info *zone_info;
+
 	/* the mode sent to blkdev_get */
 	fmode_t mode;