linux-ext4 - Re: [PATCH] ext4: respect the nobarrier mount option in nojournal mode

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Date:	Tue, 7 Jun 2016 22:23:10 -0500
From:	Eric Sandeen <sandeen@...hat.com>
To:	"Theodore Ts'o" <tytso@....edu>,
	Ext4 Developers List <linux-ext4@...r.kernel.org>
Subject: Re: [PATCH] ext4: respect the nobarrier mount option in nojournal
 mode

On 6/7/16 9:47 PM, Theodore Ts'o wrote:
> Also, if we are going to issue the barrier, we should do this after we
> write out the parent directories if necessary.
> 
> Signed-off-by: Theodore Ts'o <tytso@....edu>
> ---
>  fs/ext4/fsync.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
> index 8850254..011863e 100644
> --- a/fs/ext4/fsync.c
> +++ b/fs/ext4/fsync.c
> @@ -106,9 +106,11 @@ int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
>  	}
>  
>  	if (!journal) {
> -		ret = generic_file_fsync(file, start, end, datasync);
> +		ret = __generic_file_fsync(file, start, end, datasync);
>  		if (!ret && !hlist_empty(&inode->i_dentry))
>  			ret = ext4_sync_parent(inode);
> +		if (journal->j_flags & JBD2_BARRIER)
> +			goto issue_flush;

So in the "if (!journal)" case you test journal->j_flags?

Confused...

-Eric

>  		goto out;
>  	}
>  
> @@ -140,6 +142,7 @@ int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
>  		needs_barrier = true;
>  	ret = jbd2_complete_transaction(journal, commit_tid);
>  	if (needs_barrier) {
> +	issue_flush:
>  		err = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
>  		if (!ret)
>  			ret = err;
> 

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