Re: [f2fs-dev] [PATCH 1/1] f2fs: fix to check space of current segment journal

[Philippe De Muyter]

Tnank you for your patch.

I have applied it and also applied f2fs patches from 4.1.54 to my driver
which was in the 4.1.5 state, but I still get sometimes 

------------[ cut here ]------------
WARNING: CPU: 0 PID: 2333 at fs/f2fs/node.c:1863 flush_nat_entries+0x74c/0x7d8()
Modules linked in:
CPU: 0 PID: 2333 Comm: python3 Not tainted 4.1.15-02187-g7bc7275 #173
Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
[<80015f58>] (unwind_backtrace) from [<80012020>] (show_stack+0x10/0x14)
[<80012020>] (show_stack) from [<80733454>] (dump_stack+0x68/0xb8)
[<80733454>] (dump_stack) from [<8002b694>] (warn_slowpath_common+0x74/0xac)
[<8002b694>] (warn_slowpath_common) from [<8002b6e8>] (warn_slowpath_null+0x1c/0x24)
[<8002b6e8>] (warn_slowpath_null) from [<8024fef8>] (flush_nat_entries+0x74c/0x7d8)
[<8024fef8>] (flush_nat_entries) from [<80244b6c>] (write_checkpoint+0x208/0xe68)
[<80244b6c>] (write_checkpoint) from [<80240138>] (f2fs_sync_fs+0x50/0x70)
[<80240138>] (f2fs_sync_fs) from [<8010436c>] (sync_fs_one_sb+0x28/0x2c)
[<8010436c>] (sync_fs_one_sb) from [<800df9e0>] (iterate_supers+0xac/0xd4)
[<800df9e0>] (iterate_supers) from [<80104414>] (sys_sync+0x48/0x98)
[<80104414>] (sys_sync) from [<8000f440>] (ret_fast_syscall+0x0/0x3c)
---[ end trace a1c261161013ae57 ]---

even after a almost silent fsck :

Info: Force to fix corruption
Info: Segments per section = 1
Info: Sections per zone = 1
Info: sector size = 512
Info: total sectors = 7372800 (3600 MB)
Info: MKFS version
  ""
Info: FSCK version
  from ""
    to "Linux version 4.1.15-02187-g7bc7275 (phdm@perdita) (gcc version 4.6.2 20110630 (prerelease) (Freescale MAD -- Linaro 2011.07 -- Built at 2011/08/10 09:20) ) #173 SMP PREEMPT Thu Sep 15 18:15:41 CEST 2022"
Info: superblock features = 0 : 
Info: superblock encrypt level = 0, salt = 00000000000000000000000000000000
Info: total FS sectors = 7372800 (3600 MB)
Info: CKPT version = c68
Info: Corrupted valid nat_bits in checkpoint
Info: Write valid nat_bits in checkpoint
Info: checkpoint state = 284 :  allow_nocrc nat_bits compacted_summary sudden-power-off
[FSCK] Check node 1 / 97426 (0.00%)
random: nonblocking pool is initialized
[FSCK] Check node 9743 / 97426 (10.00%)
[FIX] (fsck_chk_inode_blk:1141)  --> Regular: 0x2387d reset i_gc_failures from 0x1 to 0x00
[FSCK] Check node 19485 / 97426 (20.00%)
[FSCK] Check node 29227 / 97426 (30.00%)
[FSCK] Check node 38969 / 97426 (40.00%)
[FSCK] Check node 48711 / 97426 (50.00%)
[FSCK] Check node 58453 / 97426 (60.00%)
[FSCK] Check node 68195 / 97426 (70.00%)
[FSCK] Check node 77937 / 97426 (80.00%)
[FSCK] Check node 87679 / 97426 (90.00%)
[FSCK] Check node 97421 / 97426 (100.00%)
[FIX] (fsck_chk_inode_blk:1141)  --> Regular: 0x23880 reset i_gc_failures from 0x1 to 0x00
[FIX] (fsck_chk_inode_blk:1141)  --> Regular: 0x23898 reset i_gc_failures from 0x1 to 0x00

[FSCK] Max image size: 3588 MB, Free space: 277 MB
[FSCK] Unreachable nat entries                        [Ok..] [0x0]
[FSCK] SIT valid block bitmap checking                [Ok..]
[FSCK] Hard link checking for regular file            [Ok..] [0xa61]
[FSCK] valid_block_count matching with CP             [Ok..] [0xbccff]
[FSCK] valid_node_count matching with CP (de lookup)  [Ok..] [0x17c92]
[FSCK] valid_node_count matching with CP (nat lookup) [Ok..] [0x17c92]
[FSCK] valid_inode_count matched with CP              [Ok..] [0x17ac4]
[FSCK] free segment_count matched with CP             [Ok..] [0x10b]
[FSCK] next block offset is free                      [Ok..]
[FSCK] fixing SIT types
[FSCK] other corrupted bugs                           [Ok..]
Info: Duplicate valid checkpoint to mirror position 1024 -> 512
Info: Write valid nat_bits in checkpoint
Info: Write valid nat_bits in checkpoint

Done: 47.791824 secs

And here is the current fs/f2fs/node.c:

        /* flush dirty nats in nat entry set */
        list_for_each_entry_safe(ne, cur, &set->entry_list, list) {
                struct f2fs_nat_entry *raw_ne;
                nid_t nid = nat_get_nid(ne);
                int offset;

                if (nat_get_blkaddr(ne) == NEW_ADDR)
                        continue;

                if (to_journal) {
                        offset = lookup_journal_in_cursum(sum,
                                                        NAT_JOURNAL, nid, 1);
LINE 1863               f2fs_bug_on(sbi, offset < 0);
                        raw_ne = &nat_in_journal(sum, offset);
                        nid_in_journal(sum, offset) = cpu_to_le32(nid);
                } else {
                        raw_ne = &nat_blk->entries[nid - start_nid];
                }
                raw_nat_from_node_info(raw_ne, &ne->ni);

                down_write(&NM_I(sbi)->nat_tree_lock);
                nat_reset_flag(ne);
                __clear_nat_cache_dirty(NM_I(sbi), ne);
                up_write(&NM_I(sbi)->nat_tree_lock);

                if (nat_get_blkaddr(ne) == NULL_ADDR)
                        add_free_nid(sbi, nid, false);
        }

Best Regards

Philippe

On Thu, Sep 15, 2022 at 03:10:04PM +0800, Wu Bo wrote:
> On 2022/9/14 16:08, Philippe De Muyter wrote:
> 
> > Hello Wu Bo,
> >
> > On Wed, Sep 14, 2022 at 12:04:23PM +0800, Wu Bo wrote:
> >> As Philippe De Muyter reported:
> >> https://lore.kernel.org/linux-f2fs-devel/20220913224908.GA25100@172.21.0.10/T/#u
> >>
> >> The warning log showed that when finding a new space for nat the journal
> >> space turned out to be full. This because the journal_rwsem is not
> >> locked before the journal space checking. The journal space may become
> >> full just after we check it.
> >>
> >> Reported-by: Philippe De Muyter <phdm@xxxxxxx>
> >> Signed-off-by: Wu Bo <bo.wu@xxxxxxxx>
> >> ---
> >>  fs/f2fs/node.c    |  6 +++---
> >>  fs/f2fs/segment.c | 10 +++++-----
> >>  2 files changed, 8 insertions(+), 8 deletions(-)
> >>
> >
> > Thank you for your patch.
> >
> > Unfortunately it does not apply to my 4.1.15 or newer 4.1.y sources,
> > and I do not have the knowledge of f2fs internals to modify your
> > patch myself.  E.g. 4.1.y lacks the '.journal' field in the
> > 'struct curseg_info'.
> >
> > Could you make a version suitable for 4.1.y ?
> 
> My patch is just try to fix the 'offset < 0' warning you have meet. The
> probability of this is very low.
> 
> 
> 
> To the fsck fixed report you found when doing fsck.f2fs, 'reset
> i_gc_failures' log seems normal. And 'Unreachable nat entries' maybe
> caused by the 'offset < 0' exception.
> 
> If your filesystem doesn't report fsck failures after these 2 cases, I
> think you don't need to worry about it too much.
> 
> Here is the patch for v4.1.y:
> 
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index 8ab0cf1930bd..fc4d87a1ddf0 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -1837,12 +1837,12 @@ static void __flush_nat_entry_set(struct f2fs_sb_info *sbi,
>          * #1, flush nat entries to journal in current hot data summary block.
>          * #2, flush nat entries to nat page.
>          */
> +       mutex_lock(&curseg->curseg_mutex);
>         if (!__has_cursum_space(sum, set->entry_cnt, NAT_JOURNAL))
>                 to_journal = false;
> 
> -       if (to_journal) {
> -               mutex_lock(&curseg->curseg_mutex);
> -       } else {
> +       if (!to_journal) {
> +               mutex_unlock(&curseg->curseg_mutex);
>                 page = get_next_nat_page(sbi, start_nid);
>                 nat_blk = page_address(page);
>                 f2fs_bug_on(sbi, !nat_blk);