Re: sysfs_chmod_file() broken in 2.6.33-rc4-git6

[ebiederm@xmission.com (Eric W. Biederman)]

Jean Delvare <khali@linux-fr.org> writes:

> Hi Eric, Greg,
>
> While working on a driver using 2.6.33-rc4-git6 as my environment, I
> have found that sysfs_chmod_file() called from a kernel driver no
> longer works. It doesn't return any error nor print any message in the
> logs, it simply has no effect. The same code worked fine using kernel
> 2.6.32. I have bisected it down to the following commit:
>
> commit e61ab4ae48fbf477f5b9fcbec9e1b8dc789920d0
> Author: Eric W. Biederman <ebiederm@xmission.com>
> Date:   Fri Nov 20 16:08:53 2009 -0800
>
>     sysfs: Implement sysfs_getattr & sysfs_permission
>     
>     With the implementation of sysfs_getattr and sysfs_permission
>     sysfs becomes able to lazily propogate inode attribute changes
>     from the sysfs_dirents to the vfs inodes.   This paves the way
>     for deleting significant chunks of now unnecessary code.
>     
>     While doing this we did not reference sysfs_setattr from
>     sysfs_symlink_inode_operations so I added along with
>     sysfs_getattr and sysfs_permission.
>     
>     Acked-by: Tejun Heo <tj@kernel.org>
>     Acked-by: Serge Hallyn <serue@us.ibm.com>
>     Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
>     Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
>
> Eric, can you please look at your code again and see if you can find
> any obvious issue?

Does this fix your issue?

Eric


diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index 220b758..6a06a1d 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -81,24 +81,23 @@ int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr * iattr)
 		if (!sd_attrs)
 			return -ENOMEM;
 		sd->s_iattr = sd_attrs;
-	} else {
-		/* attributes were changed at least once in past */
-		iattrs = &sd_attrs->ia_iattr;
-
-		if (ia_valid & ATTR_UID)
-			iattrs->ia_uid = iattr->ia_uid;
-		if (ia_valid & ATTR_GID)
-			iattrs->ia_gid = iattr->ia_gid;
-		if (ia_valid & ATTR_ATIME)
-			iattrs->ia_atime = iattr->ia_atime;
-		if (ia_valid & ATTR_MTIME)
-			iattrs->ia_mtime = iattr->ia_mtime;
-		if (ia_valid & ATTR_CTIME)
-			iattrs->ia_ctime = iattr->ia_ctime;
-		if (ia_valid & ATTR_MODE) {
-			umode_t mode = iattr->ia_mode;
-			iattrs->ia_mode = sd->s_mode = mode;
-		}
+	}
+	/* attributes were changed at least once in past */
+	iattrs = &sd_attrs->ia_iattr;
+
+	if (ia_valid & ATTR_UID)
+		iattrs->ia_uid = iattr->ia_uid;
+	if (ia_valid & ATTR_GID)
+		iattrs->ia_gid = iattr->ia_gid;
+	if (ia_valid & ATTR_ATIME)
+		iattrs->ia_atime = iattr->ia_atime;
+	if (ia_valid & ATTR_MTIME)
+		iattrs->ia_mtime = iattr->ia_mtime;
+	if (ia_valid & ATTR_CTIME)
+		iattrs->ia_ctime = iattr->ia_ctime;
+	if (ia_valid & ATTR_MODE) {
+		umode_t mode = iattr->ia_mode;
+		iattrs->ia_mode = sd->s_mode = mode;
 	}
 	return 0;
 }