Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935382AbZDBGcx (ORCPT ); Thu, 2 Apr 2009 02:32:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755296AbZDBGcl (ORCPT ); Thu, 2 Apr 2009 02:32:41 -0400 Received: from tomts43.bellnexxia.net ([209.226.175.110]:57836 "EHLO tomts43-srv.bellnexxia.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751780AbZDBGcj (ORCPT ); Thu, 2 Apr 2009 02:32:39 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AmEFAEz000lMQW1W/2dsb2JhbACBUs0Wg30G Date: Thu, 2 Apr 2009 02:32:35 -0400 From: Mathieu Desnoyers To: Suresh Jayaraman Cc: Trond.Myklebust@netapp.com, linux-nfs@vger.kernel.org, linux-embedded@vger.kernel.org, LKML , ltt-dev@lists.casi.polymtl.ca Subject: Re: [PATCH] nfs: add support for splice writes Message-ID: <20090402063235.GB24846@Krystal> References: <49D45974.2060202@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <49D45974.2060202@suse.de> X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.6.21.3-grsec (i686) X-Uptime: 02:31:55 up 33 days, 2:58, 1 user, load average: 0.38, 0.42, 0.35 User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4049 Lines: 127 * Suresh Jayaraman (sjayaraman@suse.de) wrote: > This patch attempts to add splice writes support. In essence, it just > calls generic_file_splice_write() after doing a little sanity check. > This would allow LTTng users that are using NFS to store trace data. > There could be more applications that could be benefitted too. > > I have tested this using the Jens' test program and have found no > real issues. The test program is inlined below: > There is just a small checkpatch nit that I'll fix directly in place in the LTTng tree. WARNING: %Ld/%Lu are not-standard C, use %lld/%llu #93: FILE: fs/nfs/file.c:564: + dprintk("NFS splice_write(%s/%s, %lu@%Lu)\n", total: 0 errors, 1 warnings, 42 lines checked Mathieu > /* > * splice-out.c: Splice stdout to file > */ > #include > #include > #include > #include > > #define SPLICE_SIZE (64*1024) > > int main(int argc, char *argv[]) > { > int fd; > > if (argc < 2) { > printf("%s: outfile\n", argv[0]); > return 1; > } > > fd = open(argv[1], O_WRONLY | O_CREAT | O_TRUNC, 0644); > if (fd < 0) { > perror("open"); > return 1; > } > > do { > int ret = splice(STDIN_FILENO, NULL, fd, NULL, SPLICE_SIZE, 0); > > if (ret < 0) { > perror("splice"); > break; > } else if (ret < SPLICE_SIZE) > break; > } while (1); > > close(fd); > return 0; > } > > Compile with -D _GNU_SOURCE and do something like: > echo "some stuff" | ./splice-out > > Signed-off-by: Suresh Jayaraman > --- > fs/nfs/file.c | 24 ++++++++++++++++++++++++ > 1 files changed, 24 insertions(+), 0 deletions(-) > > diff --git a/fs/nfs/file.c b/fs/nfs/file.c > index 90f292b..13d6a00 100644 > --- a/fs/nfs/file.c > +++ b/fs/nfs/file.c > @@ -47,6 +47,9 @@ 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); > @@ -76,6 +79,7 @@ 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, > }; > @@ -550,6 +554,26 @@ 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; > + > + dprintk("NFS splice_write(%s/%s, %lu@%Lu)\n", > + dentry->d_parent->d_name.name, dentry->d_name.name, > + (unsigned long) count, (unsigned long long) *ppos); > + > + if (IS_SWAPFILE(inode)) { > + printk(KERN_INFO "NFS: attempt to write to active swap" > + "file!\n"); > + return -EBUSY; > + } > + > + return generic_file_splice_write(pipe, filp, ppos, count, flags); > +} > + > static int do_getlk(struct file *filp, int cmd, struct file_lock *fl) > { > struct inode *inode = filp->f_mapping->host; > -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/