[PATCH] [RESEND] nfs: add support for splice writes

[PATCH] [RESEND] nfs: add support for splice writes

[Suresh Jayaraman]

Adds support for splice writes. It effectively calls
generic_file_splice_write() to do the writes.

We need not worry about O_APPEND case as the combination of splice()
writes and O_APPEND is disallowed. This patch propagates NFS write
errors back to the caller. The number of bytes written via splice are
being added to NFSIO_NORMALWRITTENBYTES as these are effectively
cached writes.

Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
---
 fs/nfs/file.c |   31 +++++++++++++++++++++++++++++++
 1 files changed, 31 insertions(+), 0 deletions(-)

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index ec7e27d..3f80c5e 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -48,6 +48,9 @@ static ssize_t nfs_file_splice_read(struct file *filp, loff_t *ppos,
 					size_t count, unsigned int flags);
 static ssize_t nfs_file_read(struct kiocb *, const struct iovec *iov,
 				unsigned long nr_segs, loff_t pos);
+static ssize_t nfs_file_splice_write(struct pipe_inode_info *pipe,
+					struct file *filp, loff_t *ppos,
+					size_t count, unsigned int flags);
 static ssize_t nfs_file_write(struct kiocb *, const struct iovec *iov,
 				unsigned long nr_segs, loff_t pos);
 static int  nfs_file_flush(struct file *, fl_owner_t id);
@@ -73,6 +76,7 @@ const struct file_operations nfs_file_operations = {
 	.lock		= nfs_lock,
 	.flock		= nfs_flock,
 	.splice_read	= nfs_file_splice_read,
+	.splice_write	= nfs_file_splice_write,
 	.check_flags	= nfs_check_flags,
 	.setlease	= nfs_setlease,
 };
@@ -587,6 +591,33 @@ out_swapfile:
 	goto out;
 }
 
+static ssize_t nfs_file_splice_write(struct pipe_inode_info *pipe,
+				     struct file *filp, loff_t *ppos,
+				     size_t count, unsigned int flags)
+{
+	struct dentry *dentry = filp->f_path.dentry;
+	struct inode *inode = dentry->d_inode;
+	ssize_t ret;
+
+	dprintk("NFS splice_write(%s/%s, %lu@%llu)\n",
+		dentry->d_parent->d_name.name, dentry->d_name.name,
+		(unsigned long) count, (unsigned long long) *ppos);
+
+	/*
+	 * The combination of splice and an O_APPEND destination is disallowed.
+	 */
+
+	nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count);
+
+	ret = generic_file_splice_write(pipe, filp, ppos, count, flags);
+	if (ret >= 0 && nfs_need_sync_write(filp, inode)) {
+		int err = nfs_do_fsync(nfs_file_open_context(filp), inode);
+		if (err < 0)
+			ret = err;
+	}
+	return ret;
+}
+
 static int do_getlk(struct file *filp, int cmd, struct file_lock *fl)
 {
 	struct inode *inode = filp->f_mapping->host;

Re: [PATCH] [RESEND] nfs: add support for splice writes

[Trond Myklebust]

On Mon, 2009-05-25 at 12:32 +0530, Suresh Jayaraman wrote:
> Adds support for splice writes. It effectively calls
> generic_file_splice_write() to do the writes.
> 
> We need not worry about O_APPEND case as the combination of splice()
> writes and O_APPEND is disallowed. This patch propagates NFS write
> errors back to the caller. The number of bytes written via splice are
> being added to NFSIO_NORMALWRITTENBYTES as these are effectively
> cached writes.
> 
> Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
> ---
>  fs/nfs/file.c |   31 +++++++++++++++++++++++++++++++
>  1 files changed, 31 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/nfs/file.c b/fs/nfs/file.c
> index ec7e27d..3f80c5e 100644
> --- a/fs/nfs/file.c
> +++ b/fs/nfs/file.c
> @@ -48,6 +48,9 @@ static ssize_t nfs_file_splice_read(struct file *filp, loff_t *ppos,
>  					size_t count, unsigned int flags);
>  static ssize_t nfs_file_read(struct kiocb *, const struct iovec *iov,
>  				unsigned long nr_segs, loff_t pos);
> +static ssize_t nfs_file_splice_write(struct pipe_inode_info *pipe,
> +					struct file *filp, loff_t *ppos,
> +					size_t count, unsigned int flags);
>  static ssize_t nfs_file_write(struct kiocb *, const struct iovec *iov,
>  				unsigned long nr_segs, loff_t pos);
>  static int  nfs_file_flush(struct file *, fl_owner_t id);
> @@ -73,6 +76,7 @@ const struct file_operations nfs_file_operations = {
>  	.lock		= nfs_lock,
>  	.flock		= nfs_flock,
>  	.splice_read	= nfs_file_splice_read,
> +	.splice_write	= nfs_file_splice_write,
>  	.check_flags	= nfs_check_flags,
>  	.setlease	= nfs_setlease,
>  };
> @@ -587,6 +591,33 @@ out_swapfile:
>  	goto out;
>  }
>  
> +static ssize_t nfs_file_splice_write(struct pipe_inode_info *pipe,
> +				     struct file *filp, loff_t *ppos,
> +				     size_t count, unsigned int flags)
> +{
> +	struct dentry *dentry = filp->f_path.dentry;
> +	struct inode *inode = dentry->d_inode;
> +	ssize_t ret;
> +
> +	dprintk("NFS splice_write(%s/%s, %lu@%llu)\n",
> +		dentry->d_parent->d_name.name, dentry->d_name.name,
> +		(unsigned long) count, (unsigned long long) *ppos);
> +
> +	/*
> +	 * The combination of splice and an O_APPEND destination is disallowed.
> +	 */
> +
> +	nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count);
> +
> +	ret = generic_file_splice_write(pipe, filp, ppos, count, flags);
> +	if (ret >= 0 && nfs_need_sync_write(filp, inode)) {
> +		int err = nfs_do_fsync(nfs_file_open_context(filp), inode);
> +		if (err < 0)
> +			ret = err;
> +	}
> +	return ret;
> +}
> +
>  static int do_getlk(struct file *filp, int cmd, struct file_lock *fl)
>  {
>  	struct inode *inode = filp->f_mapping->host;

Thanks Suresh! That patch looks good...

Cheers
  Trond
-- 
Trond Myklebust
Linux NFS client maintainer

NetApp
Trond.Myklebust@netapp.com
www.netapp.com