From: Miklos Szeredi <mszeredi@suse.cz>
hpfs_unlink() calls notify_change() to truncate the file before

deleting.  Replace with explicit call to hpfs_notify_change().
This is equivalent, except that:

 - security_inode_setattr() is not called before hpfs_notify_change()

 - fsnotify_change() is not called after hpfs_notify_change()
The truncation is just an implementation detail, so both the security

check and the notification are unnecessary.
Possibly even the ctime modification is wrong?
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

CC: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>

---

 fs/hpfs/namei.c |    3 ++-

 1 file changed, 2 insertions(+), 1 deletion(-)
Index: linux-2.6/fs/hpfs/namei.c

===================================================================

--- linux-2.6.orig/fs/hpfs/namei.c	2008-07-23 00:10:13.000000000 +0200

+++ linux-2.6/fs/hpfs/namei.c	2008-07-23 00:10:22.000000000 +0200

@@ -426,7 +426,8 @@ again:

 			/*printk("HPFS: truncating file before delete.\n");*/

 			newattrs.ia_size = 0;

 			newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME;

-			err = notify_change(dentry, &newattrs);

+			newattrs.ia_ctime = current_fs_time(inode->i_sb);

+			err = hpfs_notify_change(dentry, &newattrs);

 			put_write_access(inode);

 			if (!err)

 				goto again;
--

--

What about down_write on i_alloc_sem --- notify change takes that and your

patch bypasses that.
--

i_alloc_sem is only relevant if filesystem uses blockdev_direct_IO()

and friends.  It is not used for anything else, so for hpfs there's no

need to surround take that lock.
Thanks,

--

I don't care much about this part anyway. This piece of code is not

supposed to work reliably (what if the file has zero size or has fragments

less then 2kb?), and if you change it to make it work more reliably under

a circumstance when someone is deleting file he doesn't own, so what.
This is just design flaw of hpfs.
If you are certain about correctness of your patch, change it (but test

it --- I placed a test partition at

http://artax.karlin.mff.cuni.cz/~mikulas/vyplody/hpfs/test-hpfs-partitio...). 
Or, the alternative is to remove the truncate code at all.
Mikulas

--