I found an email thread [0] talking about the new way to do this. I did find a buffer overrun and will submit a patch for it. Robert LeBlanc [0] http://www.spinics.net/lists/raid/msg52300.html ---------------- Robert LeBlanc PGP Fingerprint 79A2 9CA4 6CC4 45DD A904 C70E E654 3BB2 FA62 B9F1 On Mon, Aug 22, 2016 at 10:03 AM, Robert LeBlanc <robert@xxxxxxxxxxxxx> wrote: > Apparently, the mdadm source on git-kernel.org (commit 13db17bd) > already has the fixes to properly create the device nodes, but I still > have the unexpected failure opening /dev/md1048574. > ---------------- > Robert LeBlanc > PGP Fingerprint 79A2 9CA4 6CC4 45DD A904 C70E E654 3BB2 FA62 B9F1 > > > On Fri, Aug 19, 2016 at 8:10 PM, Robert LeBlanc <robert@xxxxxxxxxxxxx> wrote: >> I'm stuck and need some help getting this across the finish line. This >> is in no way complete, but to help show what I'm working on. >> >> When we added more than 128 md devices, we started getting failures. >> Looking through the code it seems that the minor dev number was being >> stored in an int and causing overflow and wrecking havoc on everything. >> I finally got the mknod in mdadm to correctly make the dev node with >> minors up to 1048574 as expected in the mdadm code. However, I can >> only create md devices up to 511. Trying to create an md higher than >> that has an error where the device can't be read/opened strace reports: >> open("/dev/.tmp.md.15341:9:1048574", O_RDWR|O_EXCL|O_DIRECT) = -1 ENXIO >> (No such device or address) >> while Python reports: >> IOError: [Errno 6] No such device or address: '/dev/.tmp.md.3279:9:512' >> >> A corresponding node is not created in /sys/block/md* for mds over 511. >> >> I believe that there may be a bug in the kernel code that is now being >> hit. After looking through the kernel code, I can't seem to find where >> this might be. Please help me by either pointing me to the source >> location that this might be a problem or fixing it based on these >> patches I've worked on so far. I'm using 4.7.0 currently. >> >> I'm using this for testing: >> ./mdadm --create /dev/md1048574 --assume-clean --verbose --level=1 \ >> --raid-devices=2 /dev/loop0 missing >> >> Yes, we have a real need for more than 128 and 512 md devices. >> >> Please include me in any replies as I'm not on the ML. >> >> Thank you. >> >> Robert LeBlanc (1): >> Some fixes to allow for more than 128 md devices. >> >> Manage.c | 5 +++-- >> lib.c | 2 +- >> mdadm.h | 6 +++--- >> util.c | 25 +++++++++++++------------ >> 4 files changed, 20 insertions(+), 18 deletions(-) >> >> -- >> 2.8.1 >> -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
