Re: [PATCH] Extended attribute fixes, etc.

[Andreas Gruenbacher <agruen@suse.de>]

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On Tuesday 11 February 2003 21:32, Andrew Morton wrote:
> Andreas Gruenbacher <agruen@suse.de> wrote:
> > Hi Andrew,
> >
> > here are five patches against 2.5.60. Each file contains a brief
> > description of what it does.
>
> Minor point:
> ext3_journal_stop() can return an error code - most notable -EIO if
> it was a synchronous transaction, or the filesystem has detected
> corruption.

Thanks, I have overlooked this third bug. An incremental patch on top of 
my previous kernel_lock_bug.diff is attached. (I have also uploaded the 
patches to <http://acl.bestbits.at/pre/v2.5/> in the meantime).

> > The third to fifth are all steps towards trusted extended
> > attributes, which are useful for privileged processes (mostly
> > daemons). One use for this is Hierarchical Storage Management, in
> > which a user space daemon stores online/offline information for
> > files in trusted EA's, and the kernel communicates requests to
> > bring files online to that daemon. This class of EA's will also
> > find its way into XFS and ReiserFS, and expectedly also into JFS in
> > this form. (Trusted EAs are included in the 2.4.19/2.4.20 patches
> > as well.)
>
> So is this new code actually functional yet?  As in: something
> in-kernel using it?
>
> If not, what is involved in completing the kernel side of trusted
> EA's?

The important point for me now is to get the iops xattr-flags and 
xattr-flags-policy patches into 2.5 so that the API won't change during 
2.6. The xattr-trusted patch only affects file systems locally, so it's 
far less critical.

The kernel side of trusted EAs is completely implemented with the 
patches I sent. In the future there will very likely be modules 
actually making use of the XATTR_KERNEL_CONTEXT flag, but Trusted EAs 
are quite useful from user space alone.

Cheers,
Andreas.


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diff -u linux-2.5.60/fs/ext3/xattr.c linux-2.5.60/fs/ext3/xattr.c
--- linux-2.5.60/fs/ext3/xattr.c	2003-02-11 12:33:45.000000000 +0100
+++ linux-2.5.60/fs/ext3/xattr.c	2003-02-12 11:18:18.000000000 +0100
@@ -848,7 +848,7 @@
 	       const void *value, size_t value_len, int flags)
 {
 	handle_t *handle;
-	int error;
+	int error, error2;
 
 	lock_kernel();
 	handle = ext3_journal_start(inode, EXT3_XATTR_TRANS_BLOCKS);
@@ -857,10 +857,10 @@
 	else
 		error = ext3_xattr_set_handle(handle, inode, name_index, name,
 					      value, value_len, flags);
-	ext3_journal_stop(handle, inode);
+	error2 = ext3_journal_stop(handle, inode);
 	unlock_kernel();
 
-	return error;
+	return error ? error : error2;
 }
 
 /*