Messages in this thread | | | Subject | RE:(2) [PATCH v1] f2fs: Fix system crash due to lack of free space in LFS | From | Yonggil Song <> | Date | Fri, 17 Mar 2023 11:02:32 +0900 |
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>On 03/14, Yonggil Song wrote: >> When f2fs tries to checkpoint during foreground gc in LFS mode, system >> crash occurs due to lack of free space if the amount of dirty node and >> dentry pages generated by data migration exceeds free space. >> The reproduction sequence is as follows. >> >> - 20GiB capacity block device (null_blk) >> - format and mount with LFS mode >> - create a file and write 20,000MiB >> - 4k random write on full range of the file >> >> RIP: 0010:new_curseg+0x48a/0x510 [f2fs] >> Code: 55 e7 f5 89 c0 48 0f af c3 48 8b 5d c0 48 c1 e8 20 83 c0 01 89 43 6c 48 83 c4 28 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc <0f> 0b f0 41 80 4f 48 04 45 85 f6 0f 84 ba fd ff ff e9 ef fe ff ff >> RSP: 0018:ffff977bc397b218 EFLAGS: 00010246 >> RAX: 00000000000027b9 RBX: 0000000000000000 RCX: 00000000000027c0 >> RDX: 0000000000000000 RSI: 00000000000027b9 RDI: ffff8c25ab4e74f8 >> RBP: ffff977bc397b268 R08: 00000000000027b9 R09: ffff8c29e4a34b40 >> R10: 0000000000000001 R11: ffff977bc397b0d8 R12: 0000000000000000 >> R13: ffff8c25b4dd81a0 R14: 0000000000000000 R15: ffff8c2f667f9000 >> FS: 0000000000000000(0000) GS:ffff8c344ec80000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 000000c00055d000 CR3: 0000000e30810003 CR4: 00000000003706e0 >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> Call Trace: >> <TASK> >> allocate_segment_by_default+0x9c/0x110 [f2fs] >> f2fs_allocate_data_block+0x243/0xa30 [f2fs] >> ? __mod_lruvec_page_state+0xa0/0x150 >> do_write_page+0x80/0x160 [f2fs] >> f2fs_do_write_node_page+0x32/0x50 [f2fs] >> __write_node_page+0x339/0x730 [f2fs] >> f2fs_sync_node_pages+0x5a6/0x780 [f2fs] >> block_operations+0x257/0x340 [f2fs] >> f2fs_write_checkpoint+0x102/0x1050 [f2fs] >> f2fs_gc+0x27c/0x630 [f2fs] >> ? folio_mark_dirty+0x36/0x70 >> f2fs_balance_fs+0x16f/0x180 [f2fs] >> >> This patch adds checking whether free sections are enough before checkpoint >> during gc. >> >> Signed-off-by: Yonggil Song <yonggil.song@samsung.com> >> --- >> fs/f2fs/gc.c | 7 ++++++- >> fs/f2fs/segment.h | 26 +++++++++++++++++++++----- >> 2 files changed, 27 insertions(+), 6 deletions(-) >> >> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c >> index 4546e01b2ee0..b22f49a6f128 100644 >> --- a/fs/f2fs/gc.c >> +++ b/fs/f2fs/gc.c >> @@ -1773,6 +1773,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control) >> .iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS), >> }; >> unsigned int skipped_round = 0, round = 0; >> + unsigned int nr_needed_secs = 0, node_blocks = 0, dent_blocks = 0; >> >> trace_f2fs_gc_begin(sbi->sb, gc_type, gc_control->no_bg_gc, >> gc_control->nr_free_secs, >> @@ -1858,8 +1859,12 @@ int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control) >> } >> } >> >> + /* need more three extra sections for writer's data/node/dentry */ >> + nr_needed_secs = get_min_need_secs(sbi, &node_blocks, &dent_blocks) + 3; > > get_min_need_secs(&lower, &upper) > { > ... > > *lower = node_secs + dent_secs; > *upper = *lower + (node_blocks ? 1 : 0) + (dent_blocks ? 1 : 0); > } > >> + nr_needed_secs += ((node_blocks ? 1 : 0) + (dent_blocks ? 1 : 0)); >> + >> /* Write checkpoint to reclaim prefree segments */ >> - if (free_sections(sbi) < NR_CURSEG_PERSIST_TYPE && >> + if (free_sections(sbi) <= nr_needed_secs && > >#define NR_GC_CHECKPOINT_SECS (3) /* data/node/dentry sections */ > > if (free_sections(sbi) <= upper + NR_GC_CHECKPOINT_SECS && > >> prefree_segments(sbi)) { >> ret = f2fs_write_checkpoint(sbi, &cpc); >> if (ret) >> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h >> index be8f2d7d007b..ac11c47bfe37 100644 >> --- a/fs/f2fs/segment.h >> +++ b/fs/f2fs/segment.h >> @@ -605,8 +605,11 @@ static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi, >> return true; >> } >> >> -static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi, >> - int freed, int needed) >> +/* >> + * calculate the minimum number of sections (needed) for dirty node/dentry >> + */ >> +static inline unsigned int get_min_need_secs(struct f2fs_sb_info *sbi, >> + unsigned int *node_blocks, unsigned int *dent_blocks) >> { >> unsigned int total_node_blocks = get_pages(sbi, F2FS_DIRTY_NODES) + >> get_pages(sbi, F2FS_DIRTY_DENTS) + >> @@ -614,15 +617,28 @@ static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi, >> unsigned int total_dent_blocks = get_pages(sbi, F2FS_DIRTY_DENTS); >> unsigned int node_secs = total_node_blocks / CAP_BLKS_PER_SEC(sbi); >> unsigned int dent_secs = total_dent_blocks / CAP_BLKS_PER_SEC(sbi); >> - unsigned int node_blocks = total_node_blocks % CAP_BLKS_PER_SEC(sbi); >> - unsigned int dent_blocks = total_dent_blocks % CAP_BLKS_PER_SEC(sbi); >> + >> + f2fs_bug_on(sbi, (!node_blocks || !dent_blocks)); >> + >> + *node_blocks = total_node_blocks % CAP_BLKS_PER_SEC(sbi); >> + *dent_blocks = total_dent_blocks % CAP_BLKS_PER_SEC(sbi); >> + >> + return (node_secs + dent_secs); >> +} >> + >> +static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi, >> + int freed, int needed) >> +{ >> + unsigned int node_blocks = 0; >> + unsigned int dent_blocks = 0; >> unsigned int free, need_lower, need_upper; >> >> if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING))) >> return false; >> >> free = free_sections(sbi) + freed; >> - need_lower = node_secs + dent_secs + reserved_sections(sbi) + needed; >> + need_lower = get_min_need_secs(sbi, &node_blocks, &dent_blocks) + needed + >> + reserved_sections(sbi); >> need_upper = need_lower + (node_blocks ? 1 : 0) + (dent_blocks ? 1 : 0); >> >> if (free > need_upper) >> -- >> 2.34.1
Thanks for your review. I'll send a patch v2 soon.
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