Tejun Heo wrote:
Hello, This patchset implements alt_size, which is a size hint to the users of a block device. It's primarily to communicate the BIOS (HPA) size on ATA devices to userland, so that dmraid can consider it when trying to figure out BIOS raid layout. This is critical as dmraid can be tricked into assemblying the wrong raid when fed with the unlocked size and if the disk content is right (or, rather, wrong) and good number of distros are shipping with ignore_hpa=1 as default. This patch contains the following three patches. 0001-block-add-alt_size.patch 0002-scsi-add-scsi_device-alt_capacity.patch 0003-libata-export-HPA-size-as-alt_size.patch Without the above three patches, I get the following on my nv RAID-0 if HPA unlocking is turned on. # ~/work/dmraid/tools/dmraid -a y RAID set "nvidia_djgdjigi" was activated # mount /dev/dm-0 /mnt/tmp mount: wrong fs type, bad option, bad superblock on /dev/dm-0, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so With the above three patches and modified dmraid, ck804:~/os/work/build # ~/work/dmraid/tools/dmraid -a y -v -v -v ... NOTICE: /dev/sdb: using BIOS sectors 234439535 RAID set "nvidia_djgdjigi" was activated ... ck804:~/os/work/build # mount /dev/dm-0 /mnt/tmp ck804:~/os/work/build # umount /dev/dm-0
But the net result is that you are telling dmraid that it is OK to proceed, even though part of the disk it wants is really missing. That seems unwise, because are you not basically proceeding with a known corrupt dataset at that point?
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