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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Al Viro <viro@ftp.linux.org.uk>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [RFC][PATCH 10/13] make dump_emit() use vfs_write() instead of banging at ->f_op->write directly
Date: Tue, 8 Oct 2013 18:38:47 -0700	[thread overview]
Message-ID: <CA+55aFyej+u+JmWeGZgVECGFQPY909HkDc83+fuC5M1r1HSeHA@mail.gmail.com> (raw)
In-Reply-To: <20131009011833.GE13318@ZenIV.linux.org.uk>

On Tue, Oct 8, 2013 at 6:18 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> Point, but I would argue that we should yell very loud if we get 0 from
> vfs_write() for non-zero size.  I'm not sure if POSIX allows write(2)
> to return that, but a lot of userland code won't be expecting that and
> won't be able to cope...

Actually POSIX very much allows zero returns. O_NDELAY is mentioned as
a possible cause, in addition to zero-sized writes themselves, of
course.

Also, writing to (but not past) the end of a block device returns 0
for "end of device", iirc.

                Linus

  parent reply	other threads:[~2013-10-09  1:38 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-09  0:15 [RFC][PATCH 10/13] make dump_emit() use vfs_write() instead of banging at ->f_op->write directly Al Viro
2013-10-09  0:52 ` Linus Torvalds
2013-10-09  1:18   ` Al Viro
2013-10-09  1:20     ` Al Viro
2013-10-09  1:38     ` Linus Torvalds [this message]
2013-10-09  2:06       ` Al Viro
2013-10-09  2:27         ` Linus Torvalds

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