Re: [f2fs-dev] [PATCH v2 1/1] f2fs: support zone capacity less than zone size

[Chao Yu <yuchao0@huawei.com>]

On 2020/7/15 2:40, Aravind Ramesh wrote:
> Thanks for the valuable feedback.
> My comments are inline.
> Will send the V3 with the feedback incorporated.
> 
> Regards,
> Aravind
> 
>> -----Original Message-----
>> From: Chao Yu <yuchao0@huawei.com>
>> Sent: Tuesday, July 14, 2020 5:28 PM
>> To: Aravind Ramesh <Aravind.Ramesh@wdc.com>; jaegeuk@kernel.org; linux-
>> fsdevel@vger.kernel.org; linux-f2fs-devel@lists.sourceforge.net; hch@lst.de
>> Cc: Damien Le Moal <Damien.LeMoal@wdc.com>; Niklas Cassel
>> <Niklas.Cassel@wdc.com>; Matias Bjorling <Matias.Bjorling@wdc.com>
>> Subject: Re: [PATCH v2 1/1] f2fs: support zone capacity less than zone size
>>
>> On 2020/7/11 1:43, Aravind Ramesh wrote:
>>> NVMe Zoned Namespace devices can have zone-capacity less than zone-size.
>>> Zone-capacity indicates the maximum number of sectors that are usable
>>> in a zone beginning from the first sector of the zone. This makes the
>>> sectors sectors after the zone-capacity till zone-size to be unusable.
>>> This patch set tracks zone-size and zone-capacity in zoned devices and
>>> calculate the usable blocks per segment and usable segments per section.
>>>
>>> If zone-capacity is less than zone-size mark only those segments which
>>> start before zone-capacity as free segments. All segments at and
>>> beyond zone-capacity are treated as permanently used segments. In
>>> cases where zone-capacity does not align with segment size the last
>>> segment will start before zone-capacity and end beyond the
>>> zone-capacity of the zone. For such spanning segments only sectors within the
>> zone-capacity are used.
>>>
>>> During writes and GC manage the usable segments in a section and
>>> usable blocks per segment. Segments which are beyond zone-capacity are
>>> never allocated, and do not need to be garbage collected, only the
>>> segments which are before zone-capacity needs to garbage collected.
>>> For spanning segments based on the number of usable blocks in that
>>> segment, write to blocks only up to zone-capacity.
>>>
>>> Zone-capacity is device specific and cannot be configured by the user.
>>> Since NVMe ZNS device zones are sequentially write only, a block
>>> device with conventional zones or any normal block device is needed
>>> along with the ZNS device for the metadata operations of F2fs.
>>>
>>> A typical nvme-cli output of a zoned device shows zone start and
>>> capacity and write pointer as below:
>>>
>>> SLBA: 0x0     WP: 0x0     Cap: 0x18800 State: EMPTY Type: SEQWRITE_REQ
>>> SLBA: 0x20000 WP: 0x20000 Cap: 0x18800 State: EMPTY Type: SEQWRITE_REQ
>>> SLBA: 0x40000 WP: 0x40000 Cap: 0x18800 State: EMPTY Type: SEQWRITE_REQ
>>>
>>> Here zone size is 64MB, capacity is 49MB, WP is at zone start as the
>>> zones are in EMPTY state. For each zone, only zone start + 49MB is
>>> usable area, any lba/sector after 49MB cannot be read or written to,
>>> the drive will fail any attempts to read/write. So, the second zone
>>> starts at 64MB and is usable till 113MB (64 + 49) and the range
>>> between 113 and 128MB is again unusable. The next zone starts at 128MB, and so
>> on.
>>>
>>> Signed-off-by: Aravind Ramesh <aravind.ramesh@wdc.com>
>>> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
>>> Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
>>> ---
>>>  Documentation/filesystems/f2fs.rst |  15 +++
>>>  fs/f2fs/f2fs.h                     |   5 +
>>>  fs/f2fs/gc.c                       |  27 +++--
>>>  fs/f2fs/gc.h                       |  42 +++++++-
>>>  fs/f2fs/segment.c                  | 154 ++++++++++++++++++++++++++---
>>>  fs/f2fs/segment.h                  |  21 ++--
>>>  fs/f2fs/super.c                    |  41 ++++++--
>>>  7 files changed, 267 insertions(+), 38 deletions(-)
>>>
>>> diff --git a/Documentation/filesystems/f2fs.rst
>>> b/Documentation/filesystems/f2fs.rst
>>> index 535021c46260..cec2167a31db 100644
>>> --- a/Documentation/filesystems/f2fs.rst
>>> +++ b/Documentation/filesystems/f2fs.rst
>>> @@ -766,3 +766,18 @@ Compress metadata layout::
>>>  	+-------------+-------------+----------+----------------------------+
>>>  	| data length | data chksum | reserved |      compressed data       |
>>>
>>> +-------------+-------------+----------+----------------------------+
>>> +
>>> +NVMe Zoned Namespace devices
>>> +----------------------------
>>> +
>>> +- ZNS defines a per-zone capacity which can be equal or less than the
>>> +  zone-size. Zone-capacity is the number of usable blocks in the zone.
>>> +  F2fs checks if zone-capacity is less than zone-size, if it is, then
>>> +any
>>> +  segment which starts after the zone-capacity is marked as not-free
>>> +in
>>> +  the free segment bitmap at initial mount time. These segments are
>>> +marked
>>> +  as permanently used so they are not allocated for writes and
>>> +  consequently are not needed to be garbage collected. In case the
>>> +  zone-capacity is not aligned to default segment size(2MB), then a
>>> +segment
>>> +  can start before the zone-capacity and span across zone-capacity boundary.
>>> +  Such spanning segments are also considered as usable segments. All
>>> +blocks
>>> +  past the zone-capacity are considered unusable in these segments.
>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index
>>> e6e47618a357..73219e4e1ba4 100644
>>> --- a/fs/f2fs/f2fs.h
>>> +++ b/fs/f2fs/f2fs.h
>>> @@ -1232,6 +1232,7 @@ struct f2fs_dev_info {  #ifdef
>>> CONFIG_BLK_DEV_ZONED
>>>  	unsigned int nr_blkz;		/* Total number of zones */
>>>  	unsigned long *blkz_seq;	/* Bitmap indicating sequential zones */
>>> +	block_t *zone_capacity_blocks;  /* Array of zone capacity in blks */
>>>  #endif
>>>  };
>>>
>>> @@ -3395,6 +3396,10 @@ void f2fs_destroy_segment_manager_caches(void);
>>>  int f2fs_rw_hint_to_seg_type(enum rw_hint hint);  enum rw_hint
>>> f2fs_io_type_to_rw_hint(struct f2fs_sb_info *sbi,
>>>  			enum page_type type, enum temp_type temp);
>>> +unsigned int f2fs_usable_segs_in_sec(struct f2fs_sb_info *sbi,
>>> +			unsigned int segno);
>>> +unsigned int f2fs_usable_blks_in_seg(struct f2fs_sb_info *sbi,
>>> +			unsigned int segno);
>>>
>>>  /*
>>>   * checkpoint.c
>>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index
>>> 9a40761445d3..dfa6d91cffcb 100644
>>> --- a/fs/f2fs/gc.c
>>> +++ b/fs/f2fs/gc.c
>>> @@ -266,13 +266,14 @@ static unsigned int get_cb_cost(struct f2fs_sb_info
>> *sbi, unsigned int segno)
>>>  	unsigned char age = 0;
>>>  	unsigned char u;
>>>  	unsigned int i;
>>> +	unsigned int usable_segs_per_sec = f2fs_usable_segs_in_sec(sbi,
>>> +segno);
>>>
>>> -	for (i = 0; i < sbi->segs_per_sec; i++)
>>> +	for (i = 0; i < usable_segs_per_sec; i++)
>>>  		mtime += get_seg_entry(sbi, start + i)->mtime;
>>>  	vblocks = get_valid_blocks(sbi, segno, true);
>>>
>>> -	mtime = div_u64(mtime, sbi->segs_per_sec);
>>> -	vblocks = div_u64(vblocks, sbi->segs_per_sec);
>>> +	mtime = div_u64(mtime, usable_segs_per_sec);
>>> +	vblocks = div_u64(vblocks, usable_segs_per_sec);
>>>
>>>  	u = (vblocks * 100) >> sbi->log_blocks_per_seg;
>>>
>>> @@ -536,6 +537,7 @@ static int gc_node_segment(struct f2fs_sb_info *sbi,
>>>  	int phase = 0;
>>>  	bool fggc = (gc_type == FG_GC);
>>>  	int submitted = 0;
>>> +	unsigned int usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi,
>>> +segno);
>>>
>>>  	start_addr = START_BLOCK(sbi, segno);
>>>
>>> @@ -545,7 +547,7 @@ static int gc_node_segment(struct f2fs_sb_info *sbi,
>>>  	if (fggc && phase == 2)
>>>  		atomic_inc(&sbi->wb_sync_req[NODE]);
>>>
>>> -	for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
>>> +	for (off = 0; off < usable_blks_in_seg; off++, entry++) {
>>>  		nid_t nid = le32_to_cpu(entry->nid);
>>>  		struct page *node_page;
>>>  		struct node_info ni;
>>> @@ -1033,13 +1035,14 @@ static int gc_data_segment(struct f2fs_sb_info *sbi,
>> struct f2fs_summary *sum,
>>>  	int off;
>>>  	int phase = 0;
>>>  	int submitted = 0;
>>> +	unsigned int usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi,
>>> +segno);
>>>
>>>  	start_addr = START_BLOCK(sbi, segno);
>>>
>>>  next_step:
>>>  	entry = sum;
>>>
>>> -	for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
>>> +	for (off = 0; off < usable_blks_in_seg; off++, entry++) {
>>>  		struct page *data_page;
>>>  		struct inode *inode;
>>>  		struct node_info dni; /* dnode info for the data */ @@ -1201,7
>>> +1204,16 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
>>>  						SUM_TYPE_DATA :
>> SUM_TYPE_NODE;
>>>  	int submitted = 0;
>>>
>>> -	if (__is_large_section(sbi))
>>> +       /*
>>> +	* zone-capacity can be less than zone-size in zoned devices,
>>> +	* resulting in less than expected usable segments in the zone,
>>> +	* calculate the end segno in the zone which can be garbage collected
>>> +	*/
>>> +	if (f2fs_sb_has_blkzoned(sbi))
>>> +		end_segno -= sbi->segs_per_sec -
>>> +					f2fs_usable_segs_in_sec(sbi, segno);
>>> +
>>> +	else if (__is_large_section(sbi))
>>>  		end_segno = rounddown(end_segno, sbi->segs_per_sec);
>>
>> end_segno could be beyond end of section, so below calculation could adjust it to
>> the end of section first, then adjust to zone-capacity boundary.
>>
>> 	if (__is_large_section(sbi))
>> 		end_segno = rounddown(end_segno, sbi->segs_per_sec);
>>
>> 	if (f2fs_sb_has_blkzoned(sbi))
>> 		end_segno -= sbi->segs_per_sec -
>> 				f2fs_usable_segs_in_sec(sbi, segno);
> Ok, will change it.
>>
>>>
>>>  	/* readahead multi ssa blocks those have contiguous address */ @@
>>> -1356,7 +1368,8 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
>>>  		goto stop;
>>>
>>>  	seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type);
>>> -	if (gc_type == FG_GC && seg_freed == sbi->segs_per_sec)
>>> +	if (gc_type == FG_GC &&
>>> +		seg_freed == f2fs_usable_segs_in_sec(sbi, segno))
>>>  		sec_freed++;
>>>  	total_freed += seg_freed;
>>>
>>> diff --git a/fs/f2fs/gc.h b/fs/f2fs/gc.h index
>>> db3c61046aa4..463b4e38b864 100644
>>> --- a/fs/f2fs/gc.h
>>> +++ b/fs/f2fs/gc.h
>>> @@ -44,13 +44,47 @@ struct gc_inode_list {
>>>  /*
>>>   * inline functions
>>>   */
>>> +
>>> +/*
>>> + * On a Zoned device zone-capacity can be less than zone-size and if
>>> + * zone-capacity is not aligned to f2fs segment size(2MB), then the
>>> +segment
>>> + * starting just before zone-capacity has some blocks spanning across
>>> +the
>>> + * zone-capacity, these blocks are not usable.
>>> + * Such spanning segments can be in free list so calculate the sum of
>>> +usable
>>> + * blocks in currently free segments including normal and spanning segments.
>>> + */
>>> +static inline block_t free_segs_blk_count_zoned(struct f2fs_sb_info
>>> +*sbi) {
>>> +	block_t free_seg_blks = 0;
>>> +	struct free_segmap_info *free_i = FREE_I(sbi);
>>> +	int j;
>>> +
>>
>> spin_lock(&free_i->segmap_lock);
> Ok
>>
>>> +	for (j = 0; j < MAIN_SEGS(sbi); j++)
>>> +		if (!test_bit(j, free_i->free_segmap))
>>> +			free_seg_blks += f2fs_usable_blks_in_seg(sbi, j);
>>
>> spin_unlock(&free_i->segmap_lock);
> Ok
>>
>>> +
>>> +	return free_seg_blks;
>>> +}
>>> +
>>> +static inline block_t free_segs_blk_count(struct f2fs_sb_info *sbi) {
>>> +	if (f2fs_sb_has_blkzoned(sbi))
>>> +		return free_segs_blk_count_zoned(sbi);
>>> +
>>> +	return free_segments(sbi) << sbi->log_blocks_per_seg; }
>>> +
>>>  static inline block_t free_user_blocks(struct f2fs_sb_info *sbi)  {
>>> -	if (free_segments(sbi) < overprovision_segments(sbi))
>>> +	block_t free_blks, ovp_blks;
>>> +
>>> +	free_blks = free_segs_blk_count(sbi);
>>> +	ovp_blks = overprovision_segments(sbi) << sbi->log_blocks_per_seg;
>>> +
>>> +	if (free_blks < ovp_blks)
>>>  		return 0;
>>> -	else
>>> -		return (free_segments(sbi) - overprovision_segments(sbi))
>>> -			<< sbi->log_blocks_per_seg;
>>> +
>>> +	return free_blks - ovp_blks;
>>>  }
>>>
>>>  static inline block_t limit_invalid_user_blocks(struct f2fs_sb_info
>>> *sbi) diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index
>>> c35614d255e1..d75c1849dc83 100644
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -869,10 +869,10 @@ static void locate_dirty_segment(struct f2fs_sb_info
>> *sbi, unsigned int segno)
>>>  	ckpt_valid_blocks = get_ckpt_valid_blocks(sbi, segno);
>>
>> unsigned int usable_blocks = f2fs_usable_blks_in_seg(sbi, segno);
>>
>>>
>>>  	if (valid_blocks == 0 && (!is_sbi_flag_set(sbi, SBI_CP_DISABLED) ||
>>> -				ckpt_valid_blocks == sbi->blocks_per_seg)) {
>>
>> ckpt_valid_blocks == usable_blocks
>>
>>> +		ckpt_valid_blocks == f2fs_usable_blks_in_seg(sbi, segno))) {
>>>  		__locate_dirty_segment(sbi, segno, PRE);
>>>  		__remove_dirty_segment(sbi, segno, DIRTY);
>>> -	} else if (valid_blocks < sbi->blocks_per_seg) {
>>> +	} else if (valid_blocks < f2fs_usable_blks_in_seg(sbi, segno)) {
>>
>> } else if (valid_blocks < usable_blocks) {
>>
> Ok.
>>
>> BTW, would you consider to add a field as below to avoid calculation whenever we
>> want to get usable_blocks in segment:
> 
> The reason to do it like this is that f2fs supports using multiple devices to create a volume. 
> So, if 2 ZNS devices are used where both have same zone-size but different zone capacity, 
> then having this single field to indicate usable blocks will not work, as usable blocks of zones 

The field @usable_blocks in 'struct seg_entry' is per-segment, that's not single, it can be
initialized to 0 or blocks_per_seg or 'sec_cap_blkaddr - seg_start' based on its locatation
in which zone of device during build_sit_entries().

> from different devices are not same. In such a scenario, we would need to maintain an array, 
> which stores the usable blocks of each zone based on its zone-capacity.
> This approach can eliminate the calculation.
> 
> So we actually implemented this approach with a buffer and at mount time this buffer would be 
> allocated and populated with all the zone's usable_blocks information and would be read from 
> this buffer subsequently. But we did not see any performance difference when compared to 
> current approach and concluded that the overhead of calculation was negligible and also 
> current approach does not need to modify core data structure, as this field will be used 
> only when using a ZNS drive and if that drive has zone capacity less than zone size. 
> And for all other cases, the function f2fs_usable_blks_in_seg() just returns sbi->blocks_per_seg 
> without any calculation.
> 
> If you think, like the calculation overhead is more, then we need to add a pointer and allocate memory
> to it to accommodate all zone's zone-capacity info. In my opinion, the gain is very less because of the 
> reasons stated above. However, I am open to change it based on your feedback. 

I just thought those fixed size could be recorded in advance to avoid redundant
calculation, but the change I suggested is not critical, and I do agree that it
will not help performance a bit.

Anyway, I'm not against with keeping it as it is, let's go ahead. :)

> 
>>
>> struct seg_entry {
>> 	unsigned long long type:6;		/* segment type like
>> CURSEG_XXX_TYPE */
>> 	unsigned long long valid_blocks:10;	/* # of valid blocks */
>> 	unsigned long long ckpt_valid_blocks:10;	/* # of valid blocks last cp
>> */
>> 	unsigned long long usable_blocks:10;	/* usable block count in segment
>> */
>> 	unsigned long long padding:28;		/* padding */
>> ...
>>
>> For non-zns device, usable_blocks equals to blks_per_seg, otherwise it depends on
>> where it locates, we can initialize it in build_sit_entries(), thoughts?
>>
>>>  		__locate_dirty_segment(sbi, segno, DIRTY);
>>>  	} else {
>>>  		/* Recovery routine with SSR needs this */ @@ -915,9 +915,11
>> @@
>>> block_t f2fs_get_unusable_blocks(struct f2fs_sb_info *sbi)
>>>  	for_each_set_bit(segno, dirty_i->dirty_segmap[DIRTY], MAIN_SEGS(sbi)) {
>>>  		se = get_seg_entry(sbi, segno);
>>>  		if (IS_NODESEG(se->type))
>>> -			holes[NODE] += sbi->blocks_per_seg - se->valid_blocks;
>>> +			holes[NODE] += f2fs_usable_blks_in_seg(sbi, segno) -
>>> +							se->valid_blocks;
>>>  		else
>>> -			holes[DATA] += sbi->blocks_per_seg - se->valid_blocks;
>>> +			holes[DATA] += f2fs_usable_blks_in_seg(sbi, segno) -
>>> +							se->valid_blocks;
>>>  	}
>>>  	mutex_unlock(&dirty_i->seglist_lock);
>>>
>>> @@ -2167,7 +2169,7 @@ static void update_sit_entry(struct f2fs_sb_info *sbi,
>> block_t blkaddr, int del)
>>>  	offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr);
>>>
>>>  	f2fs_bug_on(sbi, (new_vblocks >> (sizeof(unsigned short) << 3) ||
>>> -				(new_vblocks > sbi->blocks_per_seg)));
>>> +			(new_vblocks > f2fs_usable_blks_in_seg(sbi, segno))));
>>>
>>>  	se->valid_blocks = new_vblocks;
>>>  	se->mtime = get_mtime(sbi, false);
>>> @@ -2933,9 +2935,9 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi,
>>> struct fstrim_range *range)  static bool __has_curseg_space(struct
>>> f2fs_sb_info *sbi, int type)  {
>>>  	struct curseg_info *curseg = CURSEG_I(sbi, type);
>>> -	if (curseg->next_blkoff < sbi->blocks_per_seg)
>>> -		return true;
>>> -	return false;
>>> +
>>> +	return curseg->next_blkoff < f2fs_usable_blks_in_seg(sbi,
>>> +							curseg->segno);
>>>  }
>>>
>>>  int f2fs_rw_hint_to_seg_type(enum rw_hint hint) @@ -4294,9 +4296,12
>>> @@ static void init_free_segmap(struct f2fs_sb_info *sbi)  {
>>>  	unsigned int start;
>>>  	int type;
>>> +	struct seg_entry *sentry;
>>>
>>>  	for (start = 0; start < MAIN_SEGS(sbi); start++) {
>>> -		struct seg_entry *sentry = get_seg_entry(sbi, start);
>>> +		if (f2fs_usable_blks_in_seg(sbi, start) == 0)
>>> +			continue;
>>> +		sentry = get_seg_entry(sbi, start);
>>>  		if (!sentry->valid_blocks)
>>>  			__set_free(sbi, start);
>>>  		else
>>> @@ -4316,7 +4321,7 @@ static void init_dirty_segmap(struct f2fs_sb_info *sbi)
>>>  	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
>>>  	struct free_segmap_info *free_i = FREE_I(sbi);
>>>  	unsigned int segno = 0, offset = 0, secno;
>>> -	unsigned short valid_blocks;
>>> +	unsigned short valid_blocks, usable_blks_in_seg;
>>>  	unsigned short blks_per_sec = BLKS_PER_SEC(sbi);
>>>
>>>  	while (1) {
>>> @@ -4326,9 +4331,10 @@ static void init_dirty_segmap(struct f2fs_sb_info *sbi)
>>>  			break;
>>>  		offset = segno + 1;
>>>  		valid_blocks = get_valid_blocks(sbi, segno, false);
>>> -		if (valid_blocks == sbi->blocks_per_seg || !valid_blocks)
>>> +		usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi, segno);
>>> +		if (valid_blocks == usable_blks_in_seg || !valid_blocks)
>>>  			continue;
>>> -		if (valid_blocks > sbi->blocks_per_seg) {
>>> +		if (valid_blocks > usable_blks_in_seg) {
>>>  			f2fs_bug_on(sbi, 1);
>>>  			continue;
>>>  		}
>>> @@ -4678,6 +4684,101 @@ int f2fs_check_write_pointer(struct
>>> f2fs_sb_info *sbi)
>>>
>>>  	return 0;
>>>  }
>>> +
>>> +static bool is_conv_zone(struct f2fs_sb_info *sbi, unsigned int zone_idx,
>>> +						unsigned int dev_idx)
>>> +{
>>> +	if (!bdev_is_zoned(FDEV(dev_idx).bdev))
>>> +		return true;
>>> +	return !test_bit(zone_idx, FDEV(dev_idx).blkz_seq); }
>>> +
>>> +/* Return the zone index in the given device */ static unsigned int
>>> +get_zone_idx(struct f2fs_sb_info *sbi, unsigned int secno,
>>> +					int dev_idx)
>>> +{
>>> +	block_t sec_start_blkaddr = START_BLOCK(sbi, GET_SEG_FROM_SEC(sbi,
>>> +secno));
>>> +
>>> +	return (sec_start_blkaddr - FDEV(dev_idx).start_blk) >>
>>> +						sbi->log_blocks_per_blkz;
>>> +}
>>> +
>>> +/*
>>> + * Return the usable segments in a section based on the zone's
>>> + * corresponding zone capacity. Zone is equal to a section.
>>> + */
>>> +static inline unsigned int f2fs_usable_zone_segs_in_sec(
>>> +		struct f2fs_sb_info *sbi, unsigned int segno) {
>>> +	unsigned int dev_idx, zone_idx, unusable_segs_in_sec;
>>> +
>>> +	dev_idx = f2fs_target_device_index(sbi, START_BLOCK(sbi, segno));
>>> +	zone_idx = get_zone_idx(sbi, GET_SEC_FROM_SEG(sbi, segno), dev_idx);
>>> +
>>> +	/* Conventional zone's capacity is always equal to zone size */
>>> +	if (is_conv_zone(sbi, zone_idx, dev_idx))
>>> +		return sbi->segs_per_sec;
>>> +
>>> +	/*
>>> +	 * If the zone_capacity_blocks array is NULL, then zone capacity
>>> +	 * is equal to the zone size for all zones
>>> +	 */
>>> +	if (!FDEV(dev_idx).zone_capacity_blocks)
>>> +		return sbi->segs_per_sec;
>>> +
>>> +	/* Get the segment count beyond zone capacity block */
>>> +	unusable_segs_in_sec = (sbi->blocks_per_blkz -
>>> +				FDEV(dev_idx).zone_capacity_blocks[zone_idx])
>>>>
>>> +				sbi->log_blocks_per_seg;
>>> +	return sbi->segs_per_sec - unusable_segs_in_sec; }
>>> +
>>> +/*
>>> + * Return the number of usable blocks in a segment. The number of
>>> +blocks
>>> + * returned is always equal to the number of blocks in a segment for
>>> + * segments fully contained within a sequential zone capacity or a
>>> + * conventional zone. For segments partially contained in a
>>> +sequential
>>> + * zone capacity, the number of usable blocks up to the zone capacity
>>> + * is returned. 0 is returned in all other cases.
>>> + */
>>> +static inline unsigned int f2fs_usable_zone_blks_in_seg(
>>> +			struct f2fs_sb_info *sbi, unsigned int segno) {
>>> +	block_t seg_start, sec_start_blkaddr, sec_cap_blkaddr;
>>> +	unsigned int zone_idx, dev_idx, secno;
>>> +
>>> +	secno = GET_SEC_FROM_SEG(sbi, segno);
>>> +	seg_start = START_BLOCK(sbi, segno);
>>> +	dev_idx = f2fs_target_device_index(sbi, seg_start);
>>> +	zone_idx = get_zone_idx(sbi, secno, dev_idx);
>>> +
>>> +	/*
>>> +	 * Conventional zone's capacity is always equal to zone size,
>>> +	 * so, blocks per segment is unchanged.
>>> +	 */
>>> +	if (is_conv_zone(sbi, zone_idx, dev_idx))
>>> +		return sbi->blocks_per_seg;
>>> +
>>> +	if (!FDEV(dev_idx).zone_capacity_blocks)
>>> +		return sbi->blocks_per_seg;
>>> +
>>> +	sec_start_blkaddr = START_BLOCK(sbi, GET_SEG_FROM_SEC(sbi, secno));
>>> +	sec_cap_blkaddr = sec_start_blkaddr +
>>> +				FDEV(dev_idx).zone_capacity_blocks[zone_idx];
>>> +
>>> +	/*
>>> +	 * If segment starts before zone capacity and spans beyond
>>> +	 * zone capacity, then usable blocks are from seg start to
>>> +	 * zone capacity. If the segment starts after the zone capacity,
>>> +	 * then there are no usable blocks.
>>> +	 */
>>> +	if (seg_start >= sec_cap_blkaddr)
>>> +		return 0;
>>> +	if (seg_start + sbi->blocks_per_seg > sec_cap_blkaddr)
>>> +		return sec_cap_blkaddr - seg_start;
>>> +
>>> +	return sbi->blocks_per_seg;
>>> +}
>>>  #else
>>>  int f2fs_fix_curseg_write_pointer(struct f2fs_sb_info *sbi)  { @@
>>> -4688,7 +4789,36 @@ int f2fs_check_write_pointer(struct f2fs_sb_info
>>> *sbi)  {
>>>  	return 0;
>>>  }
>>> +
>>> +static inline unsigned int f2fs_usable_zone_blks_in_seg(struct f2fs_sb_info *sbi,
>>> +							unsigned int segno)
>>> +{
>>> +	return 0;
>>> +}
>>> +
>>> +static inline unsigned int f2fs_usable_zone_segs_in_sec(struct f2fs_sb_info *sbi,
>>> +							unsigned int segno)
>>> +{
>>> +	return 0;
>>> +}
>>>  #endif
>>> +unsigned int f2fs_usable_blks_in_seg(struct f2fs_sb_info *sbi,
>>> +					unsigned int segno)
>>> +{
>>> +	if (f2fs_sb_has_blkzoned(sbi))
>>> +		return f2fs_usable_zone_blks_in_seg(sbi, segno);
>>> +
>>> +	return sbi->blocks_per_seg;
>>> +}
>>> +
>>> +unsigned int f2fs_usable_segs_in_sec(struct f2fs_sb_info *sbi,
>>> +					unsigned int segno)
>>> +{
>>> +	if (f2fs_sb_has_blkzoned(sbi))
>>> +		return f2fs_usable_zone_segs_in_sec(sbi, segno);
>>> +
>>> +	return sbi->segs_per_sec;
>>> +}
>>>
>>>  /*
>>>   * Update min, max modified time for cost-benefit GC algorithm diff
>>> --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index
>>> f261e3e6a69b..41bc08013160 100644
>>> --- a/fs/f2fs/segment.h
>>> +++ b/fs/f2fs/segment.h
>>> @@ -411,6 +411,7 @@ static inline void __set_free(struct f2fs_sb_info *sbi,
>> unsigned int segno)
>>>  	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
>>>  	unsigned int start_segno = GET_SEG_FROM_SEC(sbi, secno);
>>>  	unsigned int next;
>>> +	unsigned int usable_segs = f2fs_usable_segs_in_sec(sbi, segno);
>>>
>>>  	spin_lock(&free_i->segmap_lock);
>>>  	clear_bit(segno, free_i->free_segmap); @@ -418,7 +419,7 @@ static
>>> inline void __set_free(struct f2fs_sb_info *sbi, unsigned int segno)
>>>
>>>  	next = find_next_bit(free_i->free_segmap,
>>>  			start_segno + sbi->segs_per_sec, start_segno);
>>> -	if (next >= start_segno + sbi->segs_per_sec) {
>>> +	if (next >= start_segno + usable_segs) {
>>>  		clear_bit(secno, free_i->free_secmap);
>>>  		free_i->free_sections++;
>>>  	}
>>> @@ -444,6 +445,7 @@ static inline void __set_test_and_free(struct f2fs_sb_info
>> *sbi,
>>>  	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
>>>  	unsigned int start_segno = GET_SEG_FROM_SEC(sbi, secno);
>>>  	unsigned int next;
>>> +	unsigned int usable_segs = f2fs_usable_segs_in_sec(sbi, segno);
>>>
>>>  	spin_lock(&free_i->segmap_lock);
>>>  	if (test_and_clear_bit(segno, free_i->free_segmap)) { @@ -453,7
>>> +455,7 @@ static inline void __set_test_and_free(struct f2fs_sb_info *sbi,
>>>  			goto skip_free;
>>>  		next = find_next_bit(free_i->free_segmap,
>>>  				start_segno + sbi->segs_per_sec, start_segno);
>>> -		if (next >= start_segno + sbi->segs_per_sec) {
>>> +		if (next >= start_segno + usable_segs) {
>>>  			if (test_and_clear_bit(secno, free_i->free_secmap))
>>>  				free_i->free_sections++;
>>>  		}
>>> @@ -546,8 +548,8 @@ static inline bool has_curseg_enough_space(struct
>> f2fs_sb_info *sbi)
>>>  	/* check current node segment */
>>>  	for (i = CURSEG_HOT_NODE; i <= CURSEG_COLD_NODE; i++) {
>>>  		segno = CURSEG_I(sbi, i)->segno;
>>> -		left_blocks = sbi->blocks_per_seg -
>>> -			get_seg_entry(sbi, segno)->ckpt_valid_blocks;
>>> +		left_blocks = f2fs_usable_blks_in_seg(sbi, segno) -
>>> +				get_seg_entry(sbi, segno)->ckpt_valid_blocks;
>>>
>>>  		if (node_blocks > left_blocks)
>>>  			return false;
>>> @@ -555,7 +557,7 @@ static inline bool has_curseg_enough_space(struct
>>> f2fs_sb_info *sbi)
>>>
>>>  	/* check current data segment */
>>>  	segno = CURSEG_I(sbi, CURSEG_HOT_DATA)->segno;
>>> -	left_blocks = sbi->blocks_per_seg -
>>> +	left_blocks = f2fs_usable_blks_in_seg(sbi, segno) -
>>>  			get_seg_entry(sbi, segno)->ckpt_valid_blocks;
>>>  	if (dent_blocks > left_blocks)
>>>  		return false;
>>> @@ -677,21 +679,22 @@ static inline int check_block_count(struct f2fs_sb_info
>> *sbi,
>>>  	bool is_valid  = test_bit_le(0, raw_sit->valid_map) ? true : false;
>>>  	int valid_blocks = 0;
>>>  	int cur_pos = 0, next_pos;
>>> +	unsigned int usable_blks_per_seg = f2fs_usable_blks_in_seg(sbi,
>>> +segno);
>>>
>>>  	/* check bitmap with valid block count */
>>>  	do {
>>>  		if (is_valid) {
>>>  			next_pos = find_next_zero_bit_le(&raw_sit->valid_map,
>>> -					sbi->blocks_per_seg,
>>> +					usable_blks_per_seg,
>>>  					cur_pos);
>>>  			valid_blocks += next_pos - cur_pos;
>>>  		} else
>>>  			next_pos = find_next_bit_le(&raw_sit->valid_map,
>>> -					sbi->blocks_per_seg,
>>> +					usable_blks_per_seg,
>>>  					cur_pos);
>>>  		cur_pos = next_pos;
>>>  		is_valid = !is_valid;
>>> -	} while (cur_pos < sbi->blocks_per_seg);
>>> +	} while (cur_pos < usable_blks_per_seg);
>>
>> I meant we need to check that there should be no valid slot locates beyond zone-
>> capacity in bitmap:
> Ahh, ok. Got it. Will change.
>>
>> if (usable_blks_per_seg < sbi->blocks_per_seg)
>> 	f2fs_bug_on(
>> 		find_next_bit_le(&raw_sit->valid_map,
>> 				sbi->blocks_per_seg,
>> 				usable_blks_per_seg) != sbi->blocks_per_seg)
>>
>>>
>>>  	if (unlikely(GET_SIT_VBLOCKS(raw_sit) != valid_blocks)) {
>>>  		f2fs_err(sbi, "Mismatch valid blocks %d vs. %d", @@ -701,7 +704,7
>>> @@ static inline int check_block_count(struct f2fs_sb_info *sbi,
>>>  	}
>>>
>>>  	/* check segment usage, and check boundary of a given segment number */
>>> -	if (unlikely(GET_SIT_VBLOCKS(raw_sit) > sbi->blocks_per_seg
>>> +	if (unlikely(GET_SIT_VBLOCKS(raw_sit) > usable_blks_per_seg
>>>  					|| segno > TOTAL_SEGS(sbi) - 1)) {
>>>  		f2fs_err(sbi, "Wrong valid blocks %d or segno %u",
>>>  			 GET_SIT_VBLOCKS(raw_sit), segno); diff --git
>> a/fs/f2fs/super.c
>>> b/fs/f2fs/super.c index 80cb7cd358f8..7ced425dc102 100644
>>> --- a/fs/f2fs/super.c
>>> +++ b/fs/f2fs/super.c
>>> @@ -1164,6 +1164,7 @@ static void destroy_device_list(struct f2fs_sb_info *sbi)
>>>  		blkdev_put(FDEV(i).bdev, FMODE_EXCL);  #ifdef
>> CONFIG_BLK_DEV_ZONED
>>>  		kvfree(FDEV(i).blkz_seq);
>>> +		kfree(FDEV(i).zone_capacity_blocks);
>>>  #endif
>>>  	}
>>>  	kvfree(sbi->devs);
>>> @@ -3039,13 +3040,26 @@ static int init_percpu_info(struct
>>> f2fs_sb_info *sbi)  }
>>>
>>>  #ifdef CONFIG_BLK_DEV_ZONED
>>> +
>>> +struct f2fs_report_zones_args {
>>> +	struct f2fs_dev_info *dev;
>>> +	bool zone_cap_mismatch;
>>> +};
>>> +
>>>  static int f2fs_report_zone_cb(struct blk_zone *zone, unsigned int idx,
>>> -			       void *data)
>>> +			      void *data)
>>>  {
>>> -	struct f2fs_dev_info *dev = data;
>>> +	struct f2fs_report_zones_args *rz_args = data;
>>> +
>>> +	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
>>> +		return 0;
>>> +
>>> +	set_bit(idx, rz_args->dev->blkz_seq);
>>> +	rz_args->dev->zone_capacity_blocks[idx] = zone->capacity >>
>>> +						F2FS_LOG_SECTORS_PER_BLOCK;
>>> +	if (zone->len != zone->capacity && !rz_args->zone_cap_mismatch)
>>> +		rz_args->zone_cap_mismatch = true;
>>>
>>> -	if (zone->type != BLK_ZONE_TYPE_CONVENTIONAL)
>>> -		set_bit(idx, dev->blkz_seq);
>>>  	return 0;
>>>  }
>>>
>>> @@ -3053,6 +3067,7 @@ static int init_blkz_info(struct f2fs_sb_info
>>> *sbi, int devi)  {
>>>  	struct block_device *bdev = FDEV(devi).bdev;
>>>  	sector_t nr_sectors = bdev->bd_part->nr_sects;
>>> +	struct f2fs_report_zones_args rep_zone_arg;
>>>  	int ret;
>>>
>>>  	if (!f2fs_sb_has_blkzoned(sbi))
>>> @@ -3078,12 +3093,26 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int
>> devi)
>>>  	if (!FDEV(devi).blkz_seq)
>>>  		return -ENOMEM;
>>>
>>> -	/* Get block zones type */
>>> +	/* Get block zones type and zone-capacity */
>>> +	FDEV(devi).zone_capacity_blocks = f2fs_kzalloc(sbi,
>>> +					FDEV(devi).nr_blkz * sizeof(block_t),
>>> +					GFP_KERNEL);
>>> +	if (!FDEV(devi).zone_capacity_blocks)
>>> +		return -ENOMEM;
>>> +
>>> +	rep_zone_arg.dev = &FDEV(devi);
>>> +	rep_zone_arg.zone_cap_mismatch = false;
>>> +
>>>  	ret = blkdev_report_zones(bdev, 0, BLK_ALL_ZONES, f2fs_report_zone_cb,
>>> -				  &FDEV(devi));
>>> +				  &rep_zone_arg);
>>>  	if (ret < 0)
>>
>> kfree(FDEV(devi).zone_capacity_blocks);
> Actually, we do not need to free this here, because if error (ret < 0) is returned, then the control goes back to
> destroy_device_list() and deallocates the buffer.

Confirmed.

Thanks,

> 
>>
>> Thanks,
>>
>>>  		return ret;
>>>
>>> +	if (!rep_zone_arg.zone_cap_mismatch) {
>>> +		kfree(FDEV(devi).zone_capacity_blocks);
>>> +		FDEV(devi).zone_capacity_blocks = NULL;
>>> +	}
>>> +
>>>  	return 0;
>>>  }
>>>  #endif
>>>
> .
> 


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