This is version 2 of a patch series I submitted back in May 2008. This version now checks for device size changes in the rescan_partitions() routine. Which in turn is called when a device is opened and in the BLKRRPART ioctl. I am resubmitting this patch series as I got little response the previous time. Al Viro has told me offline that he would look at it this time. This patch series handles online disk resizes that are currently not completely recognized by the kernel using the existing revalidate_disk routines. An online resize can occur when growing or shrinking a Fibre Channel LUN or perhaps by adding a disk to an existing RAID volume. The kernel currently recognizes a device size change when the lower-level revalidate_disk routines are called; however, the block layer does not use the new size while it has any current openers on the device. So, for example, if LVM has an volume open on the device, you will generally not see the size change until after a reboot. We fix this problem by creating a wrapper to be used with lower-level revalidate_disk routines. This wrapper first calls the lower-level driver's revalidate_disk routine. It then compares the gendisk capacity to the block devices inode size. If there is a difference, we adjust the block device's size. If the size has changed, we then flush the disk for safety. The size is also checked in rescan_partitions which is called when the device is opened or when the BLKRRPART ioctl is called. There are several ways to "kick off" a device size change: 1. For SCSI devices do: # echo 1 > /sys/class/scsi_device/<device>/device/rescan or # blockdev --rereadpt <device file> 2. Other devices (not device mapper) # blockdev --rereadpt <device file> I have tested this patch on SCSI and SmartArray (cciss) devices. Device mapper still does not recognize device size changes until the device is restarted. Jeff Moyer and Andy Ryan have done some light testing on the previous version of this series. This patch set has been tested with scsi-misc-2.6. It also applies to linux-next with some minor, obvious changes. Diff stats: drivers/scsi/sd.c | 4 +- fs/block_dev.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++--- fs/partitions/check.c | 3 +- include/linux/fs.h | 3 ++ 4 files changed, 94 insertions(+), 8 deletions(-) Commits: - Wrapper for lower-level revalidate_disk routines. - Adjust block device size after an online resize of a disk. - Check for device resize in rescan_partitions. - SCSI sd driver calls revalidate_disk wrapper. - Added flush_disk to factor out common buffer cache flushing code. - Call flush_disk() after detecting an online resize. -- Andrew Patterson -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
