Tejun Heo wrote: > Hello, > > Alan D. Brunelle wrote: >> I have found two problems in LVM2/DM w/ a potential new "experimental >> feature" in 2.6.28: CONFIG_DEBUG_BLOCK_EXT_DEVT (this is from Jens >> Axboe's origin/for-2.6.28 git branch) > > It's a debug option and I don't expect it to be enabled in any > production kernel. Then perhaps it should /not/ default to Y... > >> "Conventionally, block device numbers are allocated from predetermined >> contiguous area. However, extended block area may introduce >> non-contiguous block device numbers. This option forces most block >> device numbers to be allocated from the extended space and spreads them >> to discover kernel or userland code paths which assume predetermined >> contiguous device number allocation." >> >> W/ LVM2 & DM there are (at least) two issues: >> >> (1) Device major numbers for some reason are /not/ being entered >> correctly into /proc/devices -- w/ CONFIG_DEBUG_BLOCK_EXT_DEVT=y I am >> seeing some devices w/ major "259" (a SATA controller) but no entry in >> /proc/devices. LVM2/DM will not find the entry in /proc/devices, and not >> allow any device w/ that major to be used with LVM commands. > > Hmmm.. Adding a call to register_blkdev(), which will create the > corresponding entry in /proc/devices, isn't difficult at all but which > name would it use? It'll be mix of block devices (hd and sds > currently). If we introduce a new name there, say, ext-block, would > that work? BTW, is there any specific reason why LVM2/DM can't use > /sys/block/* ? > >> (2) Device minor numbers can be quite large, and the 10-character limits >> in dm/lib/libdm-deptree.c are too small. > > Would it be difficult to increase that? No, but knowing the upper bound would be helpful. > > Thanks. > -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
