On Wed, May 11, 2016 at 08:39:53AM +1000, NeilBrown wrote: > On Wed, May 11 2016, Jes Sorensen wrote: > > > Mike Lovell <mike.lovell@xxxxxxxxxxxxx> writes: > >> we have a number of systems that have a large number of software > >> arrays running. its in the couple hundred range. we have been using a > >> custom built kernel based on 3.4 but are wanting to update to a > >> mainline kernel and have been experimenting with 4.4. the systems are > >> running recent centos 6 releases but we have been downgrading the > >> mdadm version from 3.3.2 in 6.7 to a custom build 3.2.6. we installed > >> the downgraded version due to a problem with array numbering. i > >> emailed the list a while ago explaining the issue and submitting a > >> patch to fix [1]. i never heard anything back and since we had a > >> simple fix i didn't follow up on it. > > > > [snip] > > > >> what do you all think? > >> > >> thanks > >> mike > >> > >> [1] http://marc.info/?l=linux-raid&m=142387809409798&w=2 > > > > Staying consistent in using dev_t rather than casting back and forth to > > int seems a reasonable fix to apply to mdadm. It obviously won't change > > the issues with the newer kernels, but I don't see any reason why we > > shouldn't apply that fix to mdadm. > > > > Neil any thoughts on this? > > I agree that changing "int" to "dev_t" is a good idea. > > We should really fix the more general problem too. > > On any kernel with /sys/module/md_mod/parameters/new_array > find_free_devnm avoid trying anything above 511. (1<<9)-1. > > If that fails to find a free number, then it should probably try a name > like "md_NN" and act as though ci->name is set. > > Also, when a "name" given for the md array that is longer than 28 bytes > we need to fall back to choose an array name ourselves even if ci->name > is set. Start with md_512 and work upwards. > Rather than probing we should read /sys/block looking for "md_*" and > maybe choose 1 more than the largest number found. I'm wondering why udev open the device with major/minor without checking if the device exists. A simple 'stat' check is neat. Thanks, Shaohua -- 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
