From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Hou Tao <houtao1@huawei.com>
Cc: hirofumi@mail.parknet.co.jp, linux-fsdevel@vger.kernel.org,
viro@zeniv.linux.org.uk, jack@suse.cz,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] fat: issue flush after the writeback of FAT
Date: Mon, 8 Apr 2019 20:41:00 -0700 [thread overview]
Message-ID: <20190409034100.GF1177@magnolia> (raw)
In-Reply-To: <20190409030158.136316-1-houtao1@huawei.com>
On Tue, Apr 09, 2019 at 11:01:58AM +0800, Hou Tao wrote:
> fsync() needs to make sure the data & meta-data of file are persistent
> after the return of fsync(), even when a power-failure occurs later.
> In the case of fat-fs, the FAT belongs to the meta-data of file,
> so we need to issue a flush after the writeback of FAT instead before.
>
> Also bail out early when any stage of fsync fails.
>
> Signed-off-by: Hou Tao <houtao1@huawei.com>
> ---
> fs/fat/file.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/fs/fat/file.c b/fs/fat/file.c
> index b3bed32946b1..0e3ed79fcc3f 100644
> --- a/fs/fat/file.c
> +++ b/fs/fat/file.c
> @@ -193,12 +193,17 @@ static int fat_file_release(struct inode *inode, struct file *filp)
> int fat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
> {
> struct inode *inode = filp->f_mapping->host;
> - int res, err;
> + int err;
> +
> + err = __generic_file_fsync(filp, start, end, datasync);
> + if (err)
> + return err;
>
> - res = generic_file_fsync(filp, start, end, datasync);
> err = sync_mapping_buffers(MSDOS_SB(inode->i_sb)->fat_inode->i_mapping);
Huh. I would've thought that flushing the FAT would also be required
at the end of a WB_SYNC_ALL (aka data integrity) writepages call?
The patch itself seems good, though.
--D
> + if (err)
> + return err;
>
> - return res ? res : err;
> + return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
> }
>
>
> --
> 2.16.2.dirty
>
next prev parent reply other threads:[~2019-04-09 3:41 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-09 3:01 [PATCH] fat: issue flush after the writeback of FAT Hou Tao
2019-04-09 3:41 ` Darrick J. Wong [this message]
2019-04-09 5:22 ` OGAWA Hirofumi
2019-04-09 5:16 ` OGAWA Hirofumi
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