Re: [RFC] readdir mess

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To: Al Viro <viro@...>
Cc: OGAWA Hirofumi <hirofumi@...>, <linux-fsdevel@...>, <linux-kernel@...>
Date: Tuesday, August 12, 2008 - 5:04 pm

On Tue, 12 Aug 2008, Al Viro wrote:

Umm. What does that matter wrt what I said?

What does that matter wrt your bogus argument about EIO (which we do 
_wrong_ right now, exactly because we return EIO too eagerly, instead of 
returning the partial data we got)?

vfs_readdir() itself would not change AT ALL. The change I talked about 
was in the caller. Which you should realize, since I actually _called_ 
vfs_readdir() in that example code.

Here's a patch to get the _semantics_ I talked about, to make the thing 
more obvious.

But the actual _change_ I talked about would be to try to avoid using 
"buf.error" entirely, and just make all the (many, I know) filesystem 
readdir() functions return the callback value instead of 0. Which would 
mean that most of the users would be able to drop their "buf.error" use 
entirely, along with the ugly

	if (error >= 0)
		error = buf.error;

that I have in this patch.

(Side note: the "if (error >= 0)" approach is what old_readdir() already 
does, so that function actually gets the EIO case _correct_: it's only 
the newer sys_getdents() that is buggy)

			Linus

---
 fs/readdir.c |    6 ++----
 1 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/readdir.c b/fs/readdir.c
index 4e026e5..e4ded16 100644
--- a/fs/readdir.c
+++ b/fs/readdir.c
@@ -205,9 +205,8 @@ asmlinkage long sys_getdents(unsigned int fd, struct linux_dirent __user * diren
 	buf.error = 0;
 
 	error = vfs_readdir(file, filldir, &buf);
-	if (error < 0)
-		goto out_putf;
-	error = buf.error;
+	if (error >= 0)
+		error = buf.error;
 	lastdirent = buf.previous;
 	if (lastdirent) {
 		if (put_user(file->f_pos, &lastdirent->d_off))
@@ -216,7 +215,6 @@ asmlinkage long sys_getdents(unsigned int fd, struct linux_dirent __user * diren
 			error = count - buf.count;
 	}
 
-out_putf:
 	fput(file);
 out:
 	return error;
--
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Messages in current thread:
[RFC] readdir mess, Al Viro, (Tue Aug 12, 2:22 am)
Re: [RFC] readdir mess, OGAWA Hirofumi, (Tue Aug 12, 1:02 pm)
Re: [RFC] readdir mess, Linus Torvalds, (Tue Aug 12, 1:18 pm)
Re: [RFC] readdir mess, OGAWA Hirofumi, (Tue Aug 12, 3:45 pm)
Re: [RFC] readdir mess, Linus Torvalds, (Tue Aug 12, 4:05 pm)
Re: [RFC] readdir mess, Alan Cox, (Tue Aug 12, 5:47 pm)
Re: [RFC] readdir mess, Linus Torvalds, (Tue Aug 12, 6:20 pm)
Re: [RFC] readdir mess, Alan Cox, (Tue Aug 12, 6:10 pm)
Re: [RFC] readdir mess, Al Viro, (Tue Aug 12, 4:59 pm)
Re: [RFC] readdir mess, Linus Torvalds, (Tue Aug 12, 5:24 pm)
Re: [RFC] readdir mess, Al Viro, (Tue Aug 12, 5:54 pm)
Re: [RFC] readdir mess, Linus Torvalds, (Tue Aug 12, 6:04 pm)
Re: [RFC] readdir mess, J. Bruce Fields, (Wed Aug 13, 12:20 pm)
Re: [RFC] readdir mess, Al Viro, (Tue Aug 12, 2:10 pm)
Re: [RFC] readdir mess, Linus Torvalds, (Tue Aug 12, 4:21 pm)
Re: [RFC] readdir mess, Al Viro, (Tue Aug 12, 4:38 pm)
Re: [RFC] readdir mess, Linus Torvalds, (Tue Aug 12, 5:04 pm)
Re: [RFC] readdir mess, Al Viro, (Tue Aug 12, 8:04 pm)
Re: [RFC] readdir mess, Jan Harkes, (Fri Aug 15, 1:06 am)
Re: [RFC] readdir mess, Linus Torvalds, (Fri Aug 15, 12:58 pm)
Re: [RFC] readdir mess, Al Viro, (Sun Aug 24, 6:10 am)
Re: [RFC] readdir mess, Linus Torvalds, (Sun Aug 24, 1:20 pm)
Re: [RFC] readdir mess, Al Viro, (Sun Aug 24, 3:59 pm)
Re: [RFC] readdir mess, Linus Torvalds, (Sun Aug 24, 7:51 pm)
Re: [RFC] readdir mess, Al Viro, (Sun Aug 24, 9:33 pm)
Re: [RFC] readdir mess, Al Viro, (Sun Aug 24, 9:44 pm)
Re: [RFC] readdir mess, Al Viro, (Sun Aug 24, 7:03 am)
Re: [RFC] readdir mess, J. Bruce Fields, (Mon Aug 25, 12:16 pm)
Re: [RFC] readdir mess, Al Viro, (Fri Aug 15, 1:34 am)
Re: [RFC] readdir mess, Brad Boyer, (Wed Aug 13, 4:36 am)
Re: [RFC] readdir mess, Al Viro, (Wed Aug 13, 12:19 pm)
Re: [RFC] readdir mess, Linus Torvalds, (Tue Aug 12, 8:28 pm)
Re: [RFC] readdir mess, Al Viro, (Tue Aug 12, 9:19 pm)
Re: [RFC] readdir mess, Linus Torvalds, (Tue Aug 12, 9:51 pm)
Re: [RFC] readdir mess, Linus Torvalds, (Tue Aug 12, 4:02 pm)
Re: [RFC] readdir mess, Al Viro, (Tue Aug 12, 2:22 pm)
Re: [RFC] readdir mess, Al Viro, (Tue Aug 12, 2:37 pm)
Re: [RFC] readdir mess, Al Viro, (Tue Aug 12, 3:24 pm)