On 10/16/25 05:11, Daeho Jeong wrote:
> From: Daeho Jeong <[email protected]>
>
> The recent increase in the number of Segment Summary Area (SSA) entries
> from 512 to 2048 was an unintentional change in logic of 16kb block
> support. This commit corrects the issue.
>
> To better utilize the space available from the erroneous 2048-entry
> calculation, we are implementing a solution to share the currently
> unused SSA space with neighboring segments. This enhances overall
> SSA utilization without impacting the established 8MB segment size.
>
> Fixes: d7e9a9037de2 ("f2fs: Support Block Size == Page Size")
> Signed-off-by: Daeho Jeong <[email protected]>
> ---
> v2: detect legacy layout and prevent mount.
> v3: error handling for a failure of f2fs_get_meta_folio().
> ---
> fs/f2fs/gc.c | 117 +++++++++++++++++++++++-----------------
> fs/f2fs/recovery.c | 2 +-
> fs/f2fs/segment.c | 29 ++++++----
> fs/f2fs/segment.h | 8 ++-
> fs/f2fs/super.c | 38 +++++++++++++
> include/linux/f2fs_fs.h | 5 +-
> 6 files changed, 136 insertions(+), 63 deletions(-)
>
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index 8abf521530ff..af2f4d28462c 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -1732,7 +1732,7 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
> unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
> SUM_TYPE_DATA : SUM_TYPE_NODE;
> unsigned char data_type = (type == SUM_TYPE_DATA) ? DATA : NODE;
> - int submitted = 0;
> + int submitted = 0, sum_blk_cnt;
>
> if (__is_large_section(sbi)) {
> sec_end_segno = rounddown(end_segno, SEGS_PER_SEC(sbi));
> @@ -1766,22 +1766,28 @@ static int do_garbage_collect(struct f2fs_sb_info
> *sbi,
>
> sanity_check_seg_type(sbi, get_seg_entry(sbi, segno)->type);
>
> + segno = rounddown(segno, SUMS_PER_BLOCK);
> + sum_blk_cnt = DIV_ROUND_UP(end_segno - segno, SUMS_PER_BLOCK);
> /* readahead multi ssa blocks those have contiguous address */
> if (__is_large_section(sbi))
> f2fs_ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
> - end_segno - segno, META_SSA, true);
> + sum_blk_cnt, META_SSA, true);
>
> /* reference all summary page */
> while (segno < end_segno) {
> - struct folio *sum_folio = f2fs_get_sum_folio(sbi, segno++);
> + struct folio *sum_folio = f2fs_get_sum_folio(sbi, segno);
> +
> + segno += SUMS_PER_BLOCK;
> if (IS_ERR(sum_folio)) {
> int err = PTR_ERR(sum_folio);
>
> - end_segno = segno - 1;
> - for (segno = start_segno; segno < end_segno; segno++) {
> + end_segno = segno - SUMS_PER_BLOCK;
> + segno = rounddown(start_segno, SUMS_PER_BLOCK);
> + while (segno < end_segno) {
> sum_folio = filemap_get_folio(META_MAPPING(sbi),
> GET_SUM_BLOCK(sbi, segno));
> folio_put_refs(sum_folio, 2);
> + segno += SUMS_PER_BLOCK;
> }
> return err;
> }
> @@ -1790,68 +1796,83 @@ static int do_garbage_collect(struct f2fs_sb_info
> *sbi,
>
> blk_start_plug(&plug);
>
> - for (segno = start_segno; segno < end_segno; segno++) {
> - struct f2fs_summary_block *sum;
> + segno = start_segno;
> + while (segno < end_segno) {
> + unsigned int cur_segno;
>
> /* find segment summary of victim */
> struct folio *sum_folio = filemap_get_folio(META_MAPPING(sbi),
> GET_SUM_BLOCK(sbi, segno));
> + unsigned int block_end_segno = rounddown(segno, SUMS_PER_BLOCK)
> + + SUMS_PER_BLOCK;
> +
> + if (block_end_segno > end_segno)
> + block_end_segno = end_segno;
>
> if (is_cursec(sbi, GET_SEC_FROM_SEG(sbi, segno))) {
> f2fs_err(sbi, "%s: segment %u is used by log",
> __func__, segno);
> f2fs_bug_on(sbi, 1);
> - goto skip;
> + goto next_block;
> }
>
> - if (get_valid_blocks(sbi, segno, false) == 0)
> - goto freed;
> - if (gc_type == BG_GC && __is_large_section(sbi) &&
> - migrated >= sbi->migration_granularity)
> - goto skip;
> if (!folio_test_uptodate(sum_folio) ||
> unlikely(f2fs_cp_error(sbi)))
> - goto skip;
> + goto next_block;
>
> - sum = folio_address(sum_folio);
> - if (type != GET_SUM_TYPE((&sum->footer))) {
> - f2fs_err(sbi, "Inconsistent segment (%u) type [%d, %d]
> in SIT and SSA",
> - segno, type, GET_SUM_TYPE((&sum->footer)));
> - f2fs_stop_checkpoint(sbi, false,
> - STOP_CP_REASON_CORRUPTED_SUMMARY);
> - goto skip;
> - }
> + for (cur_segno = segno; cur_segno < block_end_segno;
> + cur_segno++) {
> + struct f2fs_summary_block *sum;
>
> - /*
> - * this is to avoid deadlock:
> - * - lock_page(sum_page) - f2fs_replace_block
> - * - check_valid_map() - down_write(sentry_lock)
> - * - down_read(sentry_lock) - change_curseg()
> - * - lock_page(sum_page)
> - */
> - if (type == SUM_TYPE_NODE)
> - submitted += gc_node_segment(sbi, sum->entries, segno,
> - gc_type);
> - else
> - submitted += gc_data_segment(sbi, sum->entries, gc_list,
> - segno, gc_type,
> - force_migrate);
> + if (get_valid_blocks(sbi, cur_segno, false) == 0)
> + goto freed;
> + if (gc_type == BG_GC && __is_large_section(sbi) &&
> + migrated >= sbi->migration_granularity)
> + continue;
>
> - stat_inc_gc_seg_count(sbi, data_type, gc_type);
> - sbi->gc_reclaimed_segs[sbi->gc_mode]++;
> - migrated++;
> + sum = SUM_BLK_PAGE_ADDR(sum_folio, cur_segno);
> + if (type != GET_SUM_TYPE((&sum->footer))) {
> + f2fs_err(sbi, "Inconsistent segment (%u) type "
> + "[%d, %d] in SSA and SIT",
> + cur_segno, type,
> + GET_SUM_TYPE((&sum->footer)));
> + f2fs_stop_checkpoint(sbi, false,
> +
> STOP_CP_REASON_CORRUPTED_SUMMARY);
> + continue;
> + }
>
> -freed:
> - if (gc_type == FG_GC &&
> - get_valid_blocks(sbi, segno, false) == 0)
> - seg_freed++;
> + /*
> + * this is to avoid deadlock:
> + * - lock_page(sum_page) - f2fs_replace_block
> + * - check_valid_map() -
> down_write(sentry_lock)
> + * - down_read(sentry_lock) - change_curseg()
> + * - lock_page(sum_page)
> + */
> + if (type == SUM_TYPE_NODE)
> + submitted += gc_node_segment(sbi, sum->entries,
> + cur_segno, gc_type);
> + else
> + submitted += gc_data_segment(sbi, sum->entries,
> + gc_list, cur_segno,
> + gc_type, force_migrate);
>
> - if (__is_large_section(sbi))
> - sbi->next_victim_seg[gc_type] =
> - (segno + 1 < sec_end_segno) ?
> - segno + 1 : NULL_SEGNO;
> -skip:
> + stat_inc_gc_seg_count(sbi, data_type, gc_type);
> + sbi->gc_reclaimed_segs[sbi->gc_mode]++;
> + migrated++;
> +
> +freed:
> + if (gc_type == FG_GC &&
> + get_valid_blocks(sbi, cur_segno, false)
> == 0)
> + seg_freed++;
> +
> + if (__is_large_section(sbi))
> + sbi->next_victim_seg[gc_type] =
> + (cur_segno + 1 < sec_end_segno) ?
> + cur_segno + 1 : NULL_SEGNO;
> + }
> +next_block:
> folio_put_refs(sum_folio, 2);
> + segno = block_end_segno;
> }
>
> if (submitted)
> diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
> index 215e442db72c..af72309b9bfc 100644
> --- a/fs/f2fs/recovery.c
> +++ b/fs/f2fs/recovery.c
> @@ -519,7 +519,7 @@ static int check_index_in_prev_nodes(struct f2fs_sb_info
> *sbi,
> sum_folio = f2fs_get_sum_folio(sbi, segno);
> if (IS_ERR(sum_folio))
> return PTR_ERR(sum_folio);
> - sum_node = folio_address(sum_folio);
> + sum_node = SUM_BLK_PAGE_ADDR(sum_folio, segno);
> sum = sum_node->entries[blkoff];
> f2fs_folio_put(sum_folio, true);
> got_it:
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index b45eace879d7..77aa2125b8ca 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -2712,7 +2712,10 @@ struct folio *f2fs_get_sum_folio(struct f2fs_sb_info
> *sbi, unsigned int segno)
> void f2fs_update_meta_page(struct f2fs_sb_info *sbi,
> void *src, block_t blk_addr)
> {
> - struct folio *folio = f2fs_grab_meta_folio(sbi, blk_addr);
> + struct folio *folio = f2fs_get_meta_folio_retry(sbi, blk_addr);
> +
> + if (IS_ERR(folio))
> + return;
>
> memcpy(folio_address(folio), src, PAGE_SIZE);
> folio_mark_dirty(folio);
> @@ -2720,9 +2723,17 @@ void f2fs_update_meta_page(struct f2fs_sb_info *sbi,
> }
>
> static void write_sum_page(struct f2fs_sb_info *sbi,
> - struct f2fs_summary_block *sum_blk, block_t blk_addr)
> + struct f2fs_summary_block *sum_blk, unsigned int segno)
> {
> - f2fs_update_meta_page(sbi, (void *)sum_blk, blk_addr);
> + struct folio *folio;
> +
> + folio = f2fs_get_sum_folio(sbi, segno);
> + if (IS_ERR(folio))
> + return;
> +
> + memcpy(SUM_BLK_PAGE_ADDR(folio, segno), sum_blk, sizeof(*sum_blk));
> + folio_mark_dirty(folio);
> + f2fs_folio_put(folio, true);
> }
>
> static void write_current_sum_page(struct f2fs_sb_info *sbi,
> @@ -2987,7 +2998,7 @@ static int new_curseg(struct f2fs_sb_info *sbi, int
> type, bool new_sec)
> int ret;
>
> if (curseg->inited)
> - write_sum_page(sbi, curseg->sum_blk, GET_SUM_BLOCK(sbi, segno));
> + write_sum_page(sbi, curseg->sum_blk, segno);
>
> segno = __get_next_segno(sbi, type);
> ret = get_new_segment(sbi, &segno, new_sec, pinning);
> @@ -3046,7 +3057,7 @@ static int change_curseg(struct f2fs_sb_info *sbi, int
> type)
> struct folio *sum_folio;
>
> if (curseg->inited)
> - write_sum_page(sbi, curseg->sum_blk, GET_SUM_BLOCK(sbi,
> curseg->segno));
> + write_sum_page(sbi, curseg->sum_blk, curseg->segno);
>
> __set_test_and_inuse(sbi, new_segno);
>
> @@ -3065,7 +3076,7 @@ static int change_curseg(struct f2fs_sb_info *sbi, int
> type)
> memset(curseg->sum_blk, 0, SUM_ENTRY_SIZE);
> return PTR_ERR(sum_folio);
> }
> - sum_node = folio_address(sum_folio);
> + sum_node = SUM_BLK_PAGE_ADDR(sum_folio, new_segno);
> memcpy(curseg->sum_blk, sum_node, SUM_ENTRY_SIZE);
> f2fs_folio_put(sum_folio, true);
> return 0;
> @@ -3154,8 +3165,7 @@ static void __f2fs_save_inmem_curseg(struct
> f2fs_sb_info *sbi, int type)
> goto out;
>
> if (get_valid_blocks(sbi, curseg->segno, false)) {
> - write_sum_page(sbi, curseg->sum_blk,
> - GET_SUM_BLOCK(sbi, curseg->segno));
> + write_sum_page(sbi, curseg->sum_blk, curseg->segno);
> } else {
> mutex_lock(&DIRTY_I(sbi)->seglist_lock);
> __set_test_and_free(sbi, curseg->segno, true);
> @@ -3833,8 +3843,7 @@ int f2fs_allocate_data_block(struct f2fs_sb_info *sbi,
> struct folio *folio,
> if (segment_full) {
> if (type == CURSEG_COLD_DATA_PINNED &&
> !((curseg->segno + 1) % sbi->segs_per_sec)) {
> - write_sum_page(sbi, curseg->sum_blk,
> - GET_SUM_BLOCK(sbi, curseg->segno));
> + write_sum_page(sbi, curseg->sum_blk, curseg->segno);
> reset_curseg_fields(curseg);
> goto skip_new_segment;
> }
> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
> index 1ce2c8abaf48..e883f14c228f 100644
> --- a/fs/f2fs/segment.h
> +++ b/fs/f2fs/segment.h
> @@ -85,8 +85,12 @@ static inline void sanity_check_seg_type(struct
> f2fs_sb_info *sbi,
> #define GET_ZONE_FROM_SEG(sbi, segno) \
> GET_ZONE_FROM_SEC(sbi, GET_SEC_FROM_SEG(sbi, segno))
>
> -#define GET_SUM_BLOCK(sbi, segno) \
> - ((sbi)->sm_info->ssa_blkaddr + (segno))
> +#define SUMS_PER_BLOCK (F2FS_BLKSIZE / F2FS_SUM_BLKSIZE)
> +#define GET_SUM_BLOCK(sbi, segno) \
> + (SM_I(sbi)->ssa_blkaddr + (segno / SUMS_PER_BLOCK))
> +#define GET_SUM_BLKOFF(segno) (segno % SUMS_PER_BLOCK)
> +#define SUM_BLK_PAGE_ADDR(folio, segno) \
> + (folio_address(folio) + GET_SUM_BLKOFF(segno) * F2FS_SUM_BLKSIZE)
>
> #define GET_SUM_TYPE(footer) ((footer)->entry_type)
> #define SET_SUM_TYPE(footer, type) ((footer)->entry_type = (type))
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 6e52e36c1f1a..5c323850e298 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -4052,6 +4052,44 @@ static int sanity_check_raw_super(struct f2fs_sb_info
> *sbi,
> if (sanity_check_area_boundary(sbi, folio, index))
> return -EFSCORRUPTED;
>
> + /*
> + * Check for legacy summary layout on 16KB+ block devices.
> + * Modern f2fs-tools packs multiple 4KB summary areas into one block,
> + * whereas legacy versions used one block per summary, leading
> + * to a much larger SSA.
> + */
> + if (SUMS_PER_BLOCK > 1) {
> + unsigned int required_ssa_blocks;
> + unsigned int expected_ssa_segs;
> + unsigned int total_meta_segments, diff;
> + unsigned int segment_count_ssa =
> + le32_to_cpu(raw_super->segment_count_ssa);
> + unsigned int segs_per_zone = segs_per_sec * secs_per_zone;
> +
> + required_ssa_blocks = DIV_ROUND_UP(segment_count_main,
> + SUMS_PER_BLOCK);
> + expected_ssa_segs = DIV_ROUND_UP(required_ssa_blocks,
> + blocks_per_seg);
> + total_meta_segments =
> + le32_to_cpu(raw_super->segment_count_ckpt) +
> + le32_to_cpu(raw_super->segment_count_sit) +
> + le32_to_cpu(raw_super->segment_count_nat) +
> + expected_ssa_segs;
> + diff = total_meta_segments % segs_per_zone;
> + if (diff)
> + expected_ssa_segs += segs_per_zone - diff;
> +
> + if (segment_count_ssa > expected_ssa_segs) {
Daeho,
Not sure, for an extreme small-sized image, e.g. 64MB, at most, filesystem
has 32 segments, so 32 summary blocks are enough? Then, segment_count_ssa and
expected_ssa_segs could be the same (one segment)? Or am I missing something?
Thanks,
> + f2fs_info(sbi, "Error: Device formatted with a legacy "
> + "version. Please reformat.");
> + f2fs_info(sbi, "\tSSA segment count (%u) is larger "
> + "than expected (%u) for block "
> + "size (%lu).", segment_count_ssa,
> + expected_ssa_segs, F2FS_BLKSIZE);
> + return -EOPNOTSUPP;
> + }
> + }
> +
> return 0;
> }
>
> diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
> index 6afb4a13b81d..a7880787cad3 100644
> --- a/include/linux/f2fs_fs.h
> +++ b/include/linux/f2fs_fs.h
> @@ -17,6 +17,7 @@
> #define F2FS_LOG_SECTORS_PER_BLOCK (PAGE_SHIFT - 9) /* log number for
> sector/blk */
> #define F2FS_BLKSIZE PAGE_SIZE /* support only block == page
> */
> #define F2FS_BLKSIZE_BITS PAGE_SHIFT /* bits for F2FS_BLKSIZE */
> +#define F2FS_SUM_BLKSIZE 4096 /* only support 4096 byte sum
> block */
> #define F2FS_MAX_EXTENSION 64 /* # of extension entries */
> #define F2FS_EXTENSION_LEN 8 /* max size of extension */
>
> @@ -441,7 +442,7 @@ struct f2fs_sit_block {
> * from node's page's beginning to get a data block address.
> * ex) data_blkaddr = (block_t)(nodepage_start_address + ofs_in_node)
> */
> -#define ENTRIES_IN_SUM (F2FS_BLKSIZE / 8)
> +#define ENTRIES_IN_SUM (F2FS_SUM_BLKSIZE / 8)
> #define SUMMARY_SIZE (7) /* sizeof(struct f2fs_summary)
> */
> #define SUM_FOOTER_SIZE (5) /* sizeof(struct
> summary_footer) */
> #define SUM_ENTRY_SIZE (SUMMARY_SIZE * ENTRIES_IN_SUM)
> @@ -467,7 +468,7 @@ struct summary_footer {
> __le32 check_sum; /* summary checksum */
> } __packed;
>
> -#define SUM_JOURNAL_SIZE (F2FS_BLKSIZE - SUM_FOOTER_SIZE -\
> +#define SUM_JOURNAL_SIZE (F2FS_SUM_BLKSIZE - SUM_FOOTER_SIZE -\
> SUM_ENTRY_SIZE)
> #define NAT_JOURNAL_ENTRIES ((SUM_JOURNAL_SIZE - 2) /\
> sizeof(struct nat_journal_entry))
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