Re: 答复: [PATCH 1/2] f2fs: fix to skip GC if type in SSA and SIT is inconsistent

[Chao Yu <chao@kernel.org>]

Hi Xue,

On 2018/7/4 18:46, Liuxue (Alice, Euler Dept seven) wrote:
> Subject: [f2fs-dev] [PATCH 1/2] f2fs: fix to skip GC if type in SSA and SIT is inconsistent
> Date: Thu, 28 Jun 2018 18:25:58 +0800
> From: Chao Yu <yuchao0@huawei.com>
> To: jaegeuk@kernel.org
> CC: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net
> 
> If segment type in SSA and SIT is inconsistent, we will encounter below BUG_ON during GC, to avoid this panic, let's just skip doing GC on such segment.
> 
> The bug is triggered with image reported in below link:
> 
> https://bugzilla.kernel.org/show_bug.cgi?id=200223
> 
> [  388.060262] ------------[ cut here ]------------ [  388.060268] kernel BUG at /home/y00370721/git/devf2fs/gc.c:989!
> [  388.061172] invalid opcode: 0000 [#1] SMP [  388.061773] Modules linked in: f2fs(O) bluetooth ecdh_generic xt_tcpudp iptable_filter ip_tables x_tables lp ttm drm_kms_helper drm intel_rapl sb_edac crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc aesni_intel fb_sys_fops ppdev aes_x86_64 syscopyarea crypto_simd sysfillrect parport_pc joydev sysimgblt glue_helper parport cryptd i2c_piix4 serio_raw mac_hid btrfs hid_generic usbhid hid raid6_pq psmouse pata_acpi floppy
> [  388.064247] CPU: 7 PID: 4151 Comm: f2fs_gc-7:0 Tainted: G           O    4.13.0-rc1+ #26
> [  388.065306] Hardware name: Xen HVM domU, BIOS 4.1.2_115-900.260_ 11/06/2015 [  388.066058] task: ffff880201583b80 task.stack: ffffc90004d7c000 [  388.069948] RIP: 0010:do_garbage_collect+0xcc8/0xcd0 [f2fs] [  388.070766] RSP: 0018:ffffc90004d7fc68 EFLAGS: 00010202 [  388.071783] RAX: ffff8801ed227000 RBX: 0000000000000001 RCX: ffffea0007b489c0 [  388.072700] RDX: ffff880000000000 RSI: 0000000000000001 RDI: ffffea0007b489c0 [  388.073607] RBP: ffffc90004d7fd58 R08: 0000000000000003 R09: ffffea0007b489dc [  388.074619] R10: 0000000000000000 R11: 0052782ab317138d R12: 0000000000000018 [  388.075625] R13: 0000000000000018 R14: ffff880211ceb000 R15: ffff880211ceb000 [  388.076687] FS:  0000000000000000(0000) GS:ffff880214fc0000(0000) knlGS:0000000000000000 [  388.083277] CS:  0010 DS: 0000
  ES: 0000 CR0: 0000000080050033 [  388.084536] CR2: 0000000000e18c60 CR3: 00000001ecf2e000 CR4: 00000000001406e0 [  388.085748] Call Trace:
> [  388.086690]  ? find_next_bit+0xb/0x10 [  388.088091]  f2fs_gc+0x1a8/0x9d0 [f2fs] [  388.088888]  ? lock_timer_base+0x7d/0xa0 [  388.090213]  ? try_to_del_timer_sync+0x44/0x60 [  388.091698]  gc_thread_func+0x342/0x4b0 [f2fs] [  388.092892]  ? wait_woken+0x80/0x80 [  388.094098]  kthread+0x109/0x140 [  388.095010]  ? f2fs_gc+0x9d0/0x9d0 [f2fs] [  388.096043]  ? kthread_park+0x60/0x60 [  388.097281]  ret_from_fork+0x25/0x30 [  388.098401] Code: ff ff 48 83 e8 01 48 89 44 24 58 e9 27 f8 ff ff 48 83 e8 01 e9 78 fc ff ff 48 8d 78 ff e9 17 fb ff ff 48 83 ef 01 e9 4d f4 ff ff <0f> 0b 66 0f 1f 44 00 00 0f 1f 44 00 00 55 48 89 e5 41 56 41 55 [  388.100864] RIP: do_garbage_collect+0xcc8/0xcd0 [f2fs] RSP: ffffc90004d7fc68 [  388.101810] ---[ end trace 81c73d6e6b7da61d ]---
> 
> Signed-off-by: Chao Yu <yuchao0@huawei.com>
> ---
>  fs/f2fs/gc.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index da2a71eb7ee2..f3a0e2f62ce6 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -986,7 +986,12 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
>  			goto next;
>   		sum = page_address(sum_page);
> -		f2fs_bug_on(sbi, type != GET_SUM_TYPE((&sum->footer)));
> +		if (type != GET_SUM_TYPE((&sum->footer))) {
> +			f2fs_msg(sbi->sb, KERN_ERR, "Inconsistent segment (%u) "
> +				"type [%d, %d] in SSA and SIT",
> +				segno, type, GET_SUM_TYPE((&sum->footer)));
> 
> SBI_NEED_FSCK may be writed for checking disk.

Agreed, let me update the patch. :)

Thanks,

> 
> 
> +			goto next;
> +		}
>   		/*
>  		 * this is to avoid deadlock:
> --
> 2.18.0.rc1
> 
> 
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