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From: Anand Jain <anand.jain@oracle.com>
To: Damien Le Moal <Damien.LeMoal@wdc.com>,
	Naohiro Aota <Naohiro.Aota@wdc.com>,
	"linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>,
	David Sterba <dsterba@suse.com>
Cc: Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>,
	Nikolay Borisov <nborisov@suse.com>,
	Matias Bjorling <Matias.Bjorling@wdc.com>,
	Johannes Thumshirn <jthumshirn@suse.de>,
	Hannes Reinecke <hare@suse.com>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH v3 03/27] btrfs: Check and enable HMZONED mode
Date: Sat, 17 Aug 2019 07:56:50 +0800
Message-ID: <86ef7944-0029-3d61-0ae3-874015726751@oracle.com> (raw)
In-Reply-To: <BYAPR04MB5816FCD8F3A0330C8B3DC609E7AF0@BYAPR04MB5816.namprd04.prod.outlook.com>



On 8/16/19 10:23 PM, Damien Le Moal wrote:
> On 2019/08/15 22:46, Anand Jain wrote:
>> On 8/8/19 5:30 PM, Naohiro Aota wrote:
>>> HMZONED mode cannot be used together with the RAID5/6 profile for now.
>>> Introduce the function btrfs_check_hmzoned_mode() to check this. This
>>> function will also check if HMZONED flag is enabled on the file system and
>>> if the file system consists of zoned devices with equal zone size.
>>>
>>> Additionally, as updates to the space cache are in-place, the space cache
>>> cannot be located over sequential zones and there is no guarantees that the
>>> device will have enough conventional zones to store this cache. Resolve
>>> this problem by disabling completely the space cache.  This does not
>>> introduces any problems with sequential block groups: all the free space is
>>> located after the allocation pointer and no free space before the pointer.
>>> There is no need to have such cache.
>>>
>>> For the same reason, NODATACOW is also disabled.
>>>
>>> Also INODE_MAP_CACHE is also disabled to avoid preallocation in the
>>> INODE_MAP_CACHE inode.
>>
>>    A list of incompatibility features with zoned devices. This need better
>>    documentation, may be a table and its reason is better.
> 
> Are you referring to the format of the commit message itself ? Or would you like
> to see a documentation added to Documentation/filesystems/btrfs.txt ?

  Documenting in the commit change log is fine. But it can be better
  documented in a listed format as it looks like we have a list of
  features which will be incompatible with zoned devices.

more below..


>>
>>
>>> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
>>> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
>>> ---
>>>    fs/btrfs/ctree.h       |  3 ++
>>>    fs/btrfs/dev-replace.c |  8 +++++
>>>    fs/btrfs/disk-io.c     |  8 +++++
>>>    fs/btrfs/hmzoned.c     | 67 ++++++++++++++++++++++++++++++++++++++++++
>>>    fs/btrfs/hmzoned.h     | 18 ++++++++++++
>>>    fs/btrfs/super.c       |  1 +
>>>    fs/btrfs/volumes.c     |  5 ++++
>>>    7 files changed, 110 insertions(+)
>>>
>>> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
>>> index 299e11e6c554..a00ce8c4d678 100644
>>> --- a/fs/btrfs/ctree.h
>>> +++ b/fs/btrfs/ctree.h
>>> @@ -713,6 +713,9 @@ struct btrfs_fs_info {
>>>    	struct btrfs_root *uuid_root;
>>>    	struct btrfs_root *free_space_root;
>>>    
>>> +	/* Zone size when in HMZONED mode */
>>> +	u64 zone_size;
>>> +
>>>    	/* the log root tree is a directory of all the other log roots */
>>>    	struct btrfs_root *log_root_tree;
>>>    
>>> diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
>>> index 6b2e9aa83ffa..2cc3ac4d101d 100644
>>> --- a/fs/btrfs/dev-replace.c
>>> +++ b/fs/btrfs/dev-replace.c
>>> @@ -20,6 +20,7 @@
>>>    #include "rcu-string.h"
>>>    #include "dev-replace.h"
>>>    #include "sysfs.h"
>>> +#include "hmzoned.h"
>>>    
>>>    static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
>>>    				       int scrub_ret);
>>> @@ -201,6 +202,13 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
>>>    		return PTR_ERR(bdev);
>>>    	}
>>>    
>>> +	if (!btrfs_check_device_zone_type(fs_info, bdev)) {
>>> +		btrfs_err(fs_info,
>>> +			  "zone type of target device mismatch with the filesystem!");
>>> +		ret = -EINVAL;
>>> +		goto error;
>>> +	}
>>> +
>>>    	sync_blockdev(bdev);
>>>    
>>>    	devices = &fs_info->fs_devices->devices;
>>> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
>>> index 5f7ee70b3d1a..8854ff2e5fa5 100644
>>> --- a/fs/btrfs/disk-io.c
>>> +++ b/fs/btrfs/disk-io.c
>>> @@ -40,6 +40,7 @@
>>>    #include "compression.h"
>>>    #include "tree-checker.h"
>>>    #include "ref-verify.h"
>>> +#include "hmzoned.h"
>>>    
>>>    #define BTRFS_SUPER_FLAG_SUPP	(BTRFS_HEADER_FLAG_WRITTEN |\
>>>    				 BTRFS_HEADER_FLAG_RELOC |\
>>> @@ -3123,6 +3124,13 @@ int open_ctree(struct super_block *sb,
>>>    
>>>    	btrfs_free_extra_devids(fs_devices, 1);
>>>    
>>> +	ret = btrfs_check_hmzoned_mode(fs_info);
>>> +	if (ret) {
>>> +		btrfs_err(fs_info, "failed to init hmzoned mode: %d",
>>> +				ret);
>>> +		goto fail_block_groups;
>>> +	}
>>> +
>>>    	ret = btrfs_sysfs_add_fsid(fs_devices, NULL);
>>>    	if (ret) {
>>>    		btrfs_err(fs_info, "failed to init sysfs fsid interface: %d",
>>> diff --git a/fs/btrfs/hmzoned.c b/fs/btrfs/hmzoned.c
>>> index bfd04792dd62..512674d8f488 100644
>>> --- a/fs/btrfs/hmzoned.c
>>> +++ b/fs/btrfs/hmzoned.c
>>> @@ -160,3 +160,70 @@ int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
>>>    
>>>    	return 0;
>>>    }
>>> +
>>> +int btrfs_check_hmzoned_mode(struct btrfs_fs_info *fs_info)
>>> +{
>>> +	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
>>> +	struct btrfs_device *device;
>>> +	u64 hmzoned_devices = 0;
>>> +	u64 nr_devices = 0;
>>> +	u64 zone_size = 0;
>>> +	int incompat_hmzoned = btrfs_fs_incompat(fs_info, HMZONED);
>>> +	int ret = 0;
>>> +
>>> +	/* Count zoned devices */
>>> +	list_for_each_entry(device, &fs_devices->devices, dev_list) {
>>> +		if (!device->bdev)
>>> +			continue;
>>> +		if (bdev_zoned_model(device->bdev) == BLK_ZONED_HM ||
>>> +		    (bdev_zoned_model(device->bdev) == BLK_ZONED_HA &&
>>> +		     incompat_hmzoned)) {
>>> +			hmzoned_devices++;
>>> +			if (!zone_size) {
>>> +				zone_size = device->zone_info->zone_size;
>>> +			} else if (device->zone_info->zone_size != zone_size) {
>>> +				btrfs_err(fs_info,
>>> +					  "Zoned block devices must have equal zone sizes");
>>> +				ret = -EINVAL;
>>> +				goto out;
>>> +			}
>>> +		}
>>> +		nr_devices++;
>>> +	}
>>> +
>>> +	if (!hmzoned_devices && incompat_hmzoned) {
>>> +		/* No zoned block device found on HMZONED FS */
>>> +		btrfs_err(fs_info, "HMZONED enabled file system should have zoned devices");
>>> +		ret = -EINVAL;
>>> +		goto out;
>>
>>
>>    When does the HMZONED gets enabled? I presume during mkfs. Where are
>>    the related btrfs-progs patches? Searching for the related btrfs-progs
>>    patches doesn't show up anything in the ML. Looks like I am missing
>>    something, nor the cover letter said anything about the progs part.


  Any idea about this comment above?

Thanks, Anand


>> Thanks, Anand
>>
>>> +	}
>>> +
>>> +	if (!hmzoned_devices && !incompat_hmzoned)
>>> +		goto out;
>>> +
>>> +	fs_info->zone_size = zone_size;
>>> +
>>> +	if (hmzoned_devices != nr_devices) {
>>> +		btrfs_err(fs_info,
>>> +			  "zoned devices cannot be mixed with regular devices");
>>> +		ret = -EINVAL;
>>> +		goto out;
>>> +	}
>>> +
>>> +	/*
>>> +	 * stripe_size is always aligned to BTRFS_STRIPE_LEN in
>>> +	 * __btrfs_alloc_chunk(). Since we want stripe_len == zone_size,
>>> +	 * check the alignment here.
>>> +	 */
>>> +	if (!IS_ALIGNED(zone_size, BTRFS_STRIPE_LEN)) {
>>> +		btrfs_err(fs_info,
>>> +			  "zone size is not aligned to BTRFS_STRIPE_LEN");
>>> +		ret = -EINVAL;
>>> +		goto out;
>>> +	}
>>> +
>>> +	btrfs_info(fs_info, "HMZONED mode enabled, zone size %llu B",
>>> +		   fs_info->zone_size);
>>> +out:
>>> +	return ret;
>>> +}
>>> diff --git a/fs/btrfs/hmzoned.h b/fs/btrfs/hmzoned.h
>>> index ffc70842135e..29cfdcabff2f 100644
>>> --- a/fs/btrfs/hmzoned.h
>>> +++ b/fs/btrfs/hmzoned.h
>>> @@ -9,6 +9,8 @@
>>>    #ifndef BTRFS_HMZONED_H
>>>    #define BTRFS_HMZONED_H
>>>    
>>> +#include <linux/blkdev.h>
>>> +
>>>    struct btrfs_zoned_device_info {
>>>    	/*
>>>    	 * Number of zones, zone size and types of zones if bdev is a
>>> @@ -25,6 +27,7 @@ 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);
>>> +int btrfs_check_hmzoned_mode(struct btrfs_fs_info *fs_info);
>>>    
>>>    static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)
>>>    {
>>> @@ -76,4 +79,19 @@ static inline void btrfs_dev_clear_zone_empty(struct btrfs_device *device,
>>>    	btrfs_dev_set_empty_zone_bit(device, pos, false);
>>>    }
>>>    
>>> +static inline bool btrfs_check_device_zone_type(struct btrfs_fs_info *fs_info,
>>> +						struct block_device *bdev)
>>> +{
>>> +	u64 zone_size;
>>> +
>>> +	if (btrfs_fs_incompat(fs_info, HMZONED)) {
>>> +		zone_size = (u64)bdev_zone_sectors(bdev) << SECTOR_SHIFT;
>>> +		/* Do not allow non-zoned device */
>>> +		return bdev_is_zoned(bdev) && fs_info->zone_size == zone_size;
>>> +	}
>>> +
>>> +	/* Do not allow Host Manged zoned device */
>>> +	return bdev_zoned_model(bdev) != BLK_ZONED_HM;
>>> +}
>>> +
>>>    #endif
>>> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
>>> index 78de9d5d80c6..d7879a5a2536 100644
>>> --- a/fs/btrfs/super.c
>>> +++ b/fs/btrfs/super.c
>>> @@ -43,6 +43,7 @@
>>>    #include "free-space-cache.h"
>>>    #include "backref.h"
>>>    #include "space-info.h"
>>> +#include "hmzoned.h"
>>>    #include "tests/btrfs-tests.h"
>>>    
>>>    #include "qgroup.h"
>>> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
>>> index 8e5a894e7bde..755b2ec1e0de 100644
>>> --- a/fs/btrfs/volumes.c
>>> +++ b/fs/btrfs/volumes.c
>>> @@ -2572,6 +2572,11 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
>>>    	if (IS_ERR(bdev))
>>>    		return PTR_ERR(bdev);
>>>    
>>> +	if (!btrfs_check_device_zone_type(fs_info, bdev)) {
>>> +		ret = -EINVAL;
>>> +		goto error;
>>> +	}
>>> +
>>>    	if (fs_devices->seeding) {
>>>    		seeding_dev = 1;
>>>    		down_write(&sb->s_umount);
>>>
>>
>>
> 
> 

  reply index

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-08  9:30 [PATCH v3 00/27] btrfs zoned block device support Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 01/27] btrfs: introduce HMZONED feature flag Naohiro Aota
2019-08-16  4:49   ` Anand Jain
2019-08-08  9:30 ` [PATCH v3 02/27] btrfs: Get zone information of zoned block devices Naohiro Aota
2019-08-16  4:44   ` Anand Jain
2019-08-16 14:19     ` Damien Le Moal
2019-08-16 23:47       ` Anand Jain
2019-08-16 23:55         ` Damien Le Moal
2019-08-08  9:30 ` [PATCH v3 03/27] btrfs: Check and enable HMZONED mode Naohiro Aota
2019-08-16  5:46   ` Anand Jain
2019-08-16 14:23     ` Damien Le Moal
2019-08-16 23:56       ` Anand Jain [this message]
2019-08-17  0:05         ` Damien Le Moal
2019-08-20  5:07         ` Naohiro Aota
2019-08-20 13:05           ` David Sterba
2019-08-08  9:30 ` [PATCH v3 04/27] btrfs: disallow RAID5/6 in " Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 05/27] btrfs: disallow space_cache " Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 06/27] btrfs: disallow NODATACOW " Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 07/27] btrfs: disable tree-log " Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 08/27] btrfs: disable fallocate " Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 09/27] btrfs: align device extent allocation to zone boundary Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 10/27] btrfs: do sequential extent allocation in HMZONED mode Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 11/27] btrfs: make unmirroed BGs readonly only if we have at least one writable BG Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 12/27] btrfs: ensure metadata space available on/after degraded mount in HMZONED Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 13/27] btrfs: reset zones of unused block groups Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 14/27] btrfs: limit super block locations in HMZONED mode Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 15/27] btrfs: redirty released extent buffers in sequential BGs Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 16/27] btrfs: serialize data allocation and submit IOs Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 17/27] btrfs: implement atomic compressed IO submission Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 18/27] btrfs: support direct write IO in HMZONED Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 19/27] btrfs: serialize meta IOs on HMZONED mode Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 20/27] btrfs: wait existing extents before truncating Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 21/27] btrfs: avoid async checksum/submit on HMZONED mode Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 22/27] btrfs: disallow mixed-bg in " Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 23/27] btrfs: disallow inode_cache " Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 24/27] btrfs: support dev-replace " Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 25/27] btrfs: enable relocation " Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 26/27] btrfs: relocate block group to repair IO failure in HMZONED Naohiro Aota
2019-08-08  9:30 ` [PATCH v3 27/27] btrfs: enable to mount HMZONED incompat flag Naohiro Aota

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