Messages in this thread Patch in this message | | | From | Chao Yu <> | Subject | [PATCH RFC] f2fs: fix to avoid selecting full segment w/ {AT,}SSR allocator | Date | Sat, 20 Feb 2021 17:40:52 +0800 |
| |
In cp disabling mode, there could be a condition - target segment has 128 ckpt valid blocks - GC migrates 128 valid blocks to other segment (segment is still in dirty list) - GC migrates 384 blocks to target segment (segment has 128 cp_vblocks and 384 vblocks) - If GC selects target segment via {AT,}SSR allocator, however there is no free space in targe segment.
Fixes: 4354994f097d ("f2fs: checkpoint disabling") Fixes: 093749e296e2 ("f2fs: support age threshold based garbage collection") Signed-off-by: Chao Yu <yuchao0@huawei.com> --- fs/f2fs/f2fs.h | 1 + fs/f2fs/gc.c | 17 +++++++++++++---- fs/f2fs/segment.c | 20 ++++++++++++++++++++ 3 files changed, 34 insertions(+), 4 deletions(-)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index ed7807103c8e..9c753eff0814 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -3376,6 +3376,7 @@ block_t f2fs_get_unusable_blocks(struct f2fs_sb_info *sbi); int f2fs_disable_cp_again(struct f2fs_sb_info *sbi, block_t unusable); void f2fs_release_discard_addrs(struct f2fs_sb_info *sbi); int f2fs_npages_for_summary_flush(struct f2fs_sb_info *sbi, bool for_ra); +bool segment_has_free_slot(struct f2fs_sb_info *sbi, int segno); void f2fs_init_inmem_curseg(struct f2fs_sb_info *sbi); void f2fs_save_inmem_curseg(struct f2fs_sb_info *sbi); void f2fs_restore_inmem_curseg(struct f2fs_sb_info *sbi); diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index 86ba8ed0b8a7..a1d8062cdace 100644 --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -392,10 +392,6 @@ static void add_victim_entry(struct f2fs_sb_info *sbi, if (p->gc_mode == GC_AT && get_valid_blocks(sbi, segno, true) == 0) return; - - if (p->alloc_mode == AT_SSR && - get_seg_entry(sbi, segno)->ckpt_valid_blocks == 0) - return; } for (i = 0; i < sbi->segs_per_sec; i++) @@ -736,6 +732,19 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi, if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap)) goto next; + if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) { + /* + * to avoid selecting candidate which has below valid + * block distribution: + * partial blocks are valid and all left ones are valid + * in previous checkpoint. + */ + if (p.alloc_mode == SSR || p.alloc_mode == AT_SSR) { + if (!segment_has_free_slot(sbi, segno)) + goto next; + } + } + if (is_atgc) { add_victim_entry(sbi, &p, segno); goto next; diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 2d5a82c4ca15..deaf57e13125 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -2650,6 +2650,26 @@ static void __refresh_next_blkoff(struct f2fs_sb_info *sbi, seg->next_blkoff++; } +bool segment_has_free_slot(struct f2fs_sb_info *sbi, int segno) +{ + struct sit_info *sit = SIT_I(sbi); + struct seg_entry *se = get_seg_entry(sbi, segno); + int entries = SIT_VBLOCK_MAP_SIZE / sizeof(unsigned long); + unsigned long *target_map = SIT_I(sbi)->tmp_map; + unsigned long *ckpt_map = (unsigned long *)se->ckpt_valid_map; + unsigned long *cur_map = (unsigned long *)se->cur_valid_map; + int i, pos; + + down_write(&sit->sentry_lock); + for (i = 0; i < entries; i++) + target_map[i] = ckpt_map[i] | cur_map[i]; + + pos = __find_rev_next_zero_bit(target_map, sbi->blocks_per_seg, 0); + up_write(&sit->sentry_lock); + + return pos < sbi->blocks_per_seg; +} + /* * This function always allocates a used segment(from dirty seglist) by SSR * manner, so it should recover the existing segment information of valid blocks -- 2.29.2
| |