From: Al Viro <viro@ZenIV.linux.org.uk>
To: Dave Jones <davej@codemonkey.org.uk>,
Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: iov_iter_pipe warning.
Date: Wed, 12 Apr 2017 01:17:46 +0100 [thread overview]
Message-ID: <20170412001746.GM29622@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20170412000607.ob4cjv7vof3f64uu@codemonkey.org.uk>
On Tue, Apr 11, 2017 at 08:06:07PM -0400, Dave Jones wrote:
> On Wed, Apr 12, 2017 at 12:56:41AM +0100, Al Viro wrote:
> > On Wed, Apr 12, 2017 at 12:51:58AM +0100, Al Viro wrote:
> > > On Tue, Apr 11, 2017 at 07:45:58PM -0400, Dave Jones wrote:
> > > > > if (file->f_op->splice_write == generic_splice_sendpage) {
> > > > > struct socket *sock = file->private_data;
> > > > > printk(KERN_ERR "socket [%d, %p]\n", sock->type, sock->ops);
> > > > > }
> > > > > printk(KERN_ERR "in->f_op = %p\n", in->f_op);
> > > >
> > > > Ugh, this explodes with a million errors when I try to compile it.
> > > > It misses socket definition, and include <linux/net.h> causes another
> > > > cascade of errors about linkage.h and nonsense.
> > >
> > > Ignore the socket part - you've already triggered it with NFS file as
> > > destination, so this is not particularly interesting. I would still like
> > > to see in->f_op and even more - the checks in default_file_splice_read().
> >
> > ... and the latter had a braino - WARN_ON(size != ret), not len != ret.
> > Diff follows:
>
> super fast repro..
Alas, that's just another braino - it checks for non-zero ->buffers (always
true) rather than non-zero ->nrbufs (non-empty pipe). Sorry. Fixed diff
follows:
diff --git a/fs/splice.c b/fs/splice.c
index 006ba50f4ece..43dd9b3140ee 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -448,6 +448,18 @@ static ssize_t default_file_splice_read(struct file *in, loff_t *ppos,
put_page(pages[i]);
kvfree(pages);
iov_iter_advance(&to, copied); /* truncates and discards */
+ if (res > 0 && pipe == current->splice_pipe) {
+ int idx = pipe->curbuf;
+ int n = pipe->nrbufs;
+ size_t size = 0;
+ while (n--) {
+ size += pipe->bufs[idx++].len;
+ if (idx == pipe->buffers)
+ idx = 0;
+ }
+ WARN_ON(size != res);
+ }
+
return res;
}
@@ -970,6 +982,11 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
while (len) {
size_t read_len;
loff_t pos = sd->pos, prev_pos = pos;
+ if (WARN_ON(pipe->nrbufs)) {
+ printk(KERN_ERR "in->f_op = %p, ->splice_write = %p\n",
+ in->f_op,
+ sd->u.file->f_op->splice_write);
+ }
ret = do_splice_to(in, &pos, pipe, len, flags);
if (unlikely(ret <= 0))
next prev parent reply other threads:[~2017-04-12 0:17 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-21 20:59 iov_iter_pipe warning Dave Jones
2017-04-05 22:02 ` Dave Jones
2017-04-10 19:28 ` Al Viro
2017-04-10 19:42 ` Dave Jones
2017-04-10 19:57 ` Al Viro
2017-04-10 23:48 ` Dave Jones
2017-04-11 0:22 ` Al Viro
2017-04-11 3:05 ` Dave Jones
2017-04-11 3:28 ` Al Viro
2017-04-11 20:53 ` Dave Jones
2017-04-11 21:12 ` Al Viro
2017-04-11 22:25 ` Dave Jones
2017-04-11 23:28 ` Al Viro
2017-04-11 23:34 ` Dave Jones
2017-04-11 23:48 ` Al Viro
2017-04-11 23:45 ` Dave Jones
2017-04-11 23:51 ` Al Viro
2017-04-11 23:56 ` Al Viro
2017-04-12 0:06 ` Dave Jones
2017-04-12 0:17 ` Al Viro [this message]
2017-04-12 0:58 ` Dave Jones
2017-04-12 1:15 ` Al Viro
2017-04-12 2:29 ` Dave Jones
2017-04-12 2:58 ` Al Viro
2017-04-12 14:35 ` Dave Jones
2017-04-12 15:26 ` Al Viro
2017-04-12 16:27 ` Dave Jones
2017-04-12 17:07 ` Al Viro
2017-04-12 19:03 ` Dave Jones
2017-04-21 17:54 ` Al Viro
2017-04-27 4:19 ` Dave Jones
2017-04-27 16:34 ` Dave Jones
2017-04-27 17:39 ` Al Viro
2017-04-28 15:29 ` Dave Jones
2017-04-28 16:43 ` Al Viro
2017-04-28 16:50 ` Dave Jones
2017-04-28 17:20 ` Al Viro
2017-04-28 18:25 ` Al Viro
2017-04-29 1:58 ` Dave Jones
2017-04-29 2:47 ` Al Viro
2017-04-29 15:51 ` Dave Jones
2017-04-29 20:46 ` [git pull] vfs.git fix (Re: iov_iter_pipe warning.) Al Viro
2017-08-07 20:18 ` iov_iter_pipe warning Dave Jones
2017-08-28 20:31 ` Dave Jones
2017-08-29 4:25 ` Darrick J. Wong
2017-08-30 17:05 ` Dave Jones
2017-08-30 17:13 ` Darrick J. Wong
2017-08-30 17:17 ` Dave Jones
2017-09-06 20:03 ` Dave Jones
2017-09-06 23:46 ` Dave Chinner
2017-09-07 3:48 ` Dave Jones
2017-09-07 4:33 ` Al Viro
2017-09-08 1:04 ` Al Viro
2017-09-10 1:07 ` Dave Jones
2017-09-10 2:57 ` Al Viro
2017-09-10 16:07 ` Dave Jones
2017-09-10 20:05 ` Al Viro
2017-09-10 20:07 ` Dave Jones
2017-09-10 20:33 ` Al Viro
2017-09-10 21:11 ` Dave Chinner
2017-09-10 21:19 ` Al Viro
2017-09-10 22:08 ` Dave Chinner
2017-09-10 23:07 ` Al Viro
2017-09-10 23:15 ` Al Viro
2017-09-11 0:31 ` Dave Chinner
2017-09-11 3:32 ` Al Viro
2017-09-11 6:44 ` Dave Chinner
2017-09-11 20:07 ` Al Viro
2017-09-11 20:17 ` Al Viro
2017-09-12 6:02 ` Dave Chinner
2017-09-12 11:13 ` Al Viro
2017-09-11 12:07 ` Christoph Hellwig
2017-09-11 12:51 ` Al Viro
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