Hi,
On 06/26/2017 06:55 PM, Eric Ren wrote:
Hi Zdenek,
On 06/26/2017 05:46 PM, Zdenek Kabelac wrote:
Dne 26.6.2017 v 11:08 Eric Ren napsal(a):
[... snip...]
Hi
Which kernel version is this ?
I'd thought we've already fixed this BZ for old mirrors:
https://bugzilla.redhat.com/show_bug.cgi?id=1382382
There similar BZ for md-raid based mirrors (--type raid1)
https://bugzilla.redhat.com/show_bug.cgi?id=1416099
My base kernel version is 4.4.68, but with this 2 latest fixes applied:
"""
Revert "dm mirror: use all available legs on multiple failures"
dm io: fix duplicate bio completion due to missing ref count
I have a confusion about this "dm io..." fix. The fix itself is good.
Without it, a mkfs.ext4 on a mirrored dev whose primary mirror dev
has failed, will crash the kernel with the discard operation from mkfs.ext4.
However, mkfs.ext4 can succeed on a healthy mirrored device. This
is the thing I don't understand, because no matter the mirrored device is
good or not, there's always a duplicate bio completion before having this
this fix, thus write_callback() will be called twice, crashing will
occur on the
second write_callback():
"""
static void write_callback(unsigned long error, void *context)
{
unsigned i;
struct bio *bio = (struct bio *) context;
struct mirror_set *ms;
int should_wake = 0;
unsigned long flags;
ms = bio_get_m(bio)->ms; ====> NULL pointer at the
duplicate completion
bio_set_m(bio, NULL);
"""
If no this fix, I expected the DISCARD IO would always crash the kernel,
but it's not true when
the mirrored device is good. Hope someone happen to know the reason can
give some hints ;-P
Regards,
Eric
"""
Yes, I've been working on dm-mirror crash issue for couple days,
but only see this fixes above when I rebased to send my fixes out, hah.
But, with this 2 fixes, the producer can still crash the kernel.
Anyway, I can
test with upstream kernel again ;-P
Regards,
Eric
Regards
Zdenej
--
dm-devel mailing list
dm-devel@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/dm-devel
--
dm-devel mailing list
dm-devel@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/dm-devel
