On Mon, Dec 10, 2007 at 03:38:20PM +0100, Christian Borntraeger wrote: > Hi Nick, > > > Here we go. See, brd already found a bug ;) > > Can you apply the ext2 XIP patch too? And I'll resend the brd XIP patch. > [...] > > Writing to XIP files at a non-page-aligned offset results in data corruption > > because the writes were always sent to the start of the page. > [...] > > @@ -314,7 +314,7 @@ __xip_file_write(struct file *filp, cons > > fault_in_pages_readable(buf, bytes); > > kaddr = kmap_atomic(page, KM_USER0); > > copied = bytes - > > - __copy_from_user_inatomic_nocache(kaddr, buf, bytes); > > + __copy_from_user_inatomic_nocache(kaddr + offset, buf, bytes); > > kunmap_atomic(kaddr, KM_USER0); > > flush_dcache_page(page); > > I asked myself why this problem never happened before. So I asked our testers > to reproduce this problem on 2.6.23 and service levels. As the testcase did > not trigger, I looked into the 2.6.23 code. This problem was introduced by > commit 4a9e5ef1f4f15205e477817a5cefc34bd3f65f55 (mm: write iovec cleanup from > Nick Piggin) during 2.6.24-rc: > --------snip------- > - copied = filemap_copy_from_user(page, offset, buf, bytes); > [...] > + copied = bytes - > + __copy_from_user_inatomic_nocache(kaddr, buf, bytes); > ------------------- > > So yes, its good to have xip on brd. It even tests your changes ;-) > Good news is, that we dont need anything for stable. Heh ;) that explains a lot. Thanks! - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
