Re: [PATCH] nfsd: fix bad offset use

[J. Bruce Fields]

On Fri, Mar 22, 2013 at 11:18:24AM -0700, Kent Overstreet wrote:
> vfs_writev() updates the offset argument - but the code then passes the
> offset to vfs_fsync_range(). Since offset now points to the offset after
> what was just written, this is probably not what was intended

Whoops--thanks!  Looks like this was introduced by my
face15025ffdf664de95e86ae831544154d26c9c "nfsd: use vfs_fsync_range(),
not O_SYNC, for stable writes", in 3.8.

I'll queue up for 3.9 and stable.

--b.

> 
> Signed-off-by: Kent Overstreet <koverstreet@xxxxxxxxxx>
> Cc: "J. Bruce Fields" <bfields@xxxxxxxxxxxx>
> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
> Cc: Zach Brown <zab@xxxxxxxxxx>
> ---
>  fs/nfsd/vfs.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index 2a7eb53..2b2e239 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -1013,6 +1013,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
>  	int			host_err;
>  	int			stable = *stablep;
>  	int			use_wgather;
> +	loff_t			pos = offset;
>  
>  	dentry = file->f_path.dentry;
>  	inode = dentry->d_inode;
> @@ -1025,7 +1026,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
>  
>  	/* Write the data. */
>  	oldfs = get_fs(); set_fs(KERNEL_DS);
> -	host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &offset);
> +	host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &pos);
>  	set_fs(oldfs);
>  	if (host_err < 0)
>  		goto out_nfserr;
> -- 
> 1.8.1.3
> 
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