[PATCH] libfs: return error code on failed attr set

[PATCH] libfs: return error code on failed attr set

[Wu Fengguang]

Currently all simple_attr.set handlers return 0 on success and negative
codes on error. Fix simple_attr_write() to return these error codes.

CC: Theodore Ts'o <tytso@mit.edu>
CC: Al Viro <viro@zeniv.linux.org.uk>
CC: Christoph Hellwig <hch@lst.de>
CC: Nick Piggin <npiggin@suse.de>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
 fs/libfs.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- linux-mm.orig/fs/libfs.c	2009-09-08 16:28:59.000000000 +0800
+++ linux-mm/fs/libfs.c	2009-09-08 16:29:50.000000000 +0800
@@ -822,10 +822,11 @@ ssize_t simple_attr_write(struct file *f
 	if (copy_from_user(attr->set_buf, buf, size))
 		goto out;
 
-	ret = len; /* claim we got the whole input */
 	attr->set_buf[size] = '\0';
 	val = simple_strtol(attr->set_buf, NULL, 0);
-	attr->set(attr->data, val);
+	ret = attr->set(attr->data, val);
+	if (ret == 0)
+		ret = len; /* on success, claim we got the whole input */
 out:
 	mutex_unlock(&attr->mutex);
 	return ret;

Re: [PATCH] libfs: return error code on failed attr set

[Christoph Hellwig]

On Fri, Sep 11, 2009 at 06:50:31PM +0800, Wu Fengguang wrote:
> Currently all simple_attr.set handlers return 0 on success and negative
> codes on error. Fix simple_attr_write() to return these error codes.

Looks good to me assuming you actually audited all the implementations
to do the right thing.

Re: [PATCH] libfs: return error code on failed attr set

[Wu Fengguang]

On Sat, Sep 12, 2009 at 02:29:30AM +0800, Christoph Hellwig wrote:
> On Fri, Sep 11, 2009 at 06:50:31PM +0800, Wu Fengguang wrote:
> > Currently all simple_attr.set handlers return 0 on success and negative
> > codes on error. Fix simple_attr_write() to return these error codes.
> 
> Looks good to me assuming you actually audited all the implementations
> to do the right thing.

Yes I checked all DEFINE_SIMPLE_ATTRIBUTE users. All the _set()
handlers returns 0 for success and negative error code for failure.

Thanks,
Fengguang