linux-kernel - Re: [f2fs-dev] [PATCH] f2fs: clean up w/ sbi->log_sectors_per

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Message-ID: <fafcfeosil5yqwn2wcdx33im2mq4xkejw6bx7h2in3ay5h6znj@facx4rrg4p65>
Date:   Fri, 4 Aug 2023 09:43:29 +0000
From:   Shinichiro Kawasaki <shinichiro.kawasaki@....com>
To:     Chao Yu <chao@...nel.org>
CC:     "jaegeuk@...nel.org" <jaegeuk@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-f2fs-devel@...ts.sourceforge.net" 
        <linux-f2fs-devel@...ts.sourceforge.net>,
        Damien Le Moal <Damien.LeMoal@....com>
Subject: Re: [f2fs-dev] [PATCH] f2fs: clean up w/ sbi->log_sectors_per_block

On May 23, 2023 / 20:35, Chao Yu wrote:
> Use sbi->log_sectors_per_block to clean up below calculated one:
> 
> unsigned int log_sectors_per_block = sbi->log_blocksize - SECTOR_SHIFT;

Hello Chao,

When I ran workloads on f2fs using v6.5-rcX with fixes [1][2] and a zoned block
devices with 4kb logical block size, I observe mount failure as follows. When
I revert this commit, the failure goes away.

[  167.781975][ T1555] F2FS-fs (dm-0): IO Block Size:        4 KB
[  167.890728][ T1555] F2FS-fs (dm-0): Found nat_bits in checkpoint
[  171.482588][ T1555] F2FS-fs (dm-0): Zone without valid block has non-zero write pointer. Reset the write pointer: wp[0x1300,0x8]
[  171.496000][ T1555] F2FS-fs (dm-0): (0) : Unaligned zone reset attempted (block 280000 + 80000)
[  171.505037][ T1555] F2FS-fs (dm-0): Discard zone failed:  (errno=-5)

The patch replaced "sbi->log_blocksize - SECTOR_SHIFT" with
"sbi->log_sectors_per_block". However, I think these two are not equal when the
device has 4k logical block size. The former uses Linux kernel sector size 512
byte. The latter use 512b sector size or 4kb sector size depending on the
device. mkfs.f2fs obtains logical block size via BLKSSZGET ioctl from the device
and reflects it to the value sbi->log_sector_size_per_block. This causes
unexpected write pointer calculations in check_zone_write_pointer(). This
resulted in unexpected zone reset and the mount failure.

I think this patch needs revert. What do you think?

[1] https://lkml.kernel.org/linux-f2fs-devel/20230711050101.GA19128@lst.de/
[2] https://lore.kernel.org/linux-f2fs-devel/20230804091556.2372567-1-shinichiro.kawasaki@wdc.com/