On Mon, 2009-06-08 at 19:50 +0000, Dave Anderson wrote: Regarding blkext 259 > > Correction -- it does appear in the major_names[] array, in a 2.6.30 > kernel for example, like this: > > crash> p * major_names[4] > $51 = { > next = 0x0, > major = 259, > name = "blkext\000\000\000\000\000\000\000\000\000" > } > > where it appears to be the only major_names[] entry whose "major" value > doesn't equal the index into the array (i.e., 259 != 4). But the > bdev_map.probes[4] entry is unused. The blkext is supposed to get used as soon as someone wants to put more than 15 partitions on an sd disk. (Explanation at http://thread.gmane.org/gmane.linux.kernel/701825) Then the upper partitions will appear as minors of 259. When that starts happening more, having a way to see it might (*might*) be interesting. > > At this point I'm about ready to deprecate the whole command... ;-) And at this point I couldn't really argue much :-) I obviously hadn't used the command for a while. I was casting around, hoping it would maybe help me find the diskstats stuff for the block devices. I was trying to answer a question like "How much disk activity was going on before this crashed?" When I tried the dev command and it bombed at the chrdev stuff before getting to the blkdev stuff, I was motivated to get it going enough to see if it would help answer my question, but it doesn't print anything (like hd_struct pointers) that could help me with my problem. But I figured someone had once wanted that device info, so it might as well work...