From: Eric Sandeen <sandeen@redhat.com>
Subject: Re: [PATCH] ext4: fix blkdev_issue_flush() failure handling
Date: Sun, 29 Mar 2009 12:43:22 -0500
Message-ID: <49CFB33A.9020406@redhat.com>
References: <200903291928.14451.bzolnier@gmail.com>
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Cc: "Theodore Ts'o" <tytso@mit.edu>, linux-ext4@vger.kernel.org,
	linux-kernel@vger.kernel.org
To: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
In-Reply-To: <200903291928.14451.bzolnier@gmail.com>
Sender: linux-ext4-owner@vger.kernel.org

Bartlomiej Zolnierkiewicz wrote:
> blkdev_issue_flush() may fail (i.e. due to media error on FLUSH CACHE
> command execution) so its users should check for the return value.
> 
> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
> ---
>  fs/ext4/fsync.c |    9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> Index: b/fs/ext4/fsync.c
> ===================================================================
> --- a/fs/ext4/fsync.c
> +++ b/fs/ext4/fsync.c
> @@ -48,7 +48,7 @@ int ext4_sync_file(struct file *file, st
>  {
>  	struct inode *inode = dentry->d_inode;
>  	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
> -	int ret = 0;
> +	int ret = 0, tmp_ret;
>  
>  	J_ASSERT(ext4_journal_current_handle() == NULL);
>  
> @@ -92,8 +92,11 @@ int ext4_sync_file(struct file *file, st
>  			.nr_to_write = 0, /* sys_fsync did this */
>  		};
>  		ret = sync_inode(inode, &wbc);
> -		if (journal && (journal->j_flags & JBD2_BARRIER))
> -			blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
> +		if (journal && (journal->j_flags & JBD2_BARRIER)) {
> +			tmp_ret = blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
> +			if (ret == 0 && tmp_ret < 0 && tmp_ret != -EOPNOTSUPP)
> +				ret = tmp_ret;
> +		}
>  	}
>  out:
>  	return ret;

As long as we keep the call there this is probably good, but after
talking w/ Chris Mason, I think the call is extraneous anyway and should
probably just be removed...

-Eric