On Friday 19 October 2007 16:05, Erez Zadok wrote:
> David,
>
> I'm testing unionfs on top of jffs2, using 2.6.24 as of linus's commit
> 4fa4d23fa20de67df919030c1216295664866ad7. All of my unionfs tests pass
> when unionfs is stacked on top of jffs2, other than my truncate test --
> whic tries to truncate files up/down (through the union, which then is
> passed through to the lower jffs2 f/s). The same truncate test passes on
> all other file systems I've tried unionfs/2.6.24 with, as well as all of
> the earlier kernels that unionfs runs on (2.6.9--2.6.23). So I tend to
> think this bug is more probably due to something else going on in 2.6.24,
> possibly wrt jffs2/mtd. (Of course, it's still possible that unionfs isn't
> doing something right -- any pointers?)
>
> The oops trace is included below. Is this a known issue and if so, any
> fixes? If this is the first you hear of this problem, let me know and I'll
> try to narrow it down further.
It's had quite a lot of recent changes in that area -- the "new aops"
patches.
They've been getting quite a bit of testing in -mm and no such problems,
but I doubt anyone was doing much unionfs over jffs2, or even much jffs2
testing with -mm.
The bug smells like jffs2 is actually passing back a "written" length
greater than the length we passed into it.
The following might show what's happening.
Index: linux-2.6/mm/filemap.c
===================================================================
--- linux-2.6.orig/mm/filemap.c
+++ linux-2.6/mm/filemap.c
@@ -2184,6 +2184,7 @@ fs_write_aop_error:
return written ? written : status;
}
+#include <linux/kallsyms.h>
static ssize_t generic_perform_write(struct file *file,
struct iov_iter *i, loff_t pos)
{
@@ -2243,6 +2244,13 @@ again:
page, fsdata);
if (unlikely(status < 0))
break;
+ if (status > copied) {
+ print_symbol("%s returned more than it should!\n", (unsigned long)a_ops->write_end);
+ printk("status = %ld, copied = %lu\n", status, copied);
+ dump_stack();
+ status = copied; /* try to fix */
+ }
+
copied = status;
cond_resched();
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
