Messages in this thread | | | Date | Thu, 29 Dec 2011 12:20:10 +0800 | From | Wu Fengguang <> | Subject | Re: Bug in BLKBSZSET/GET ioctl ? |
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On Thu, Dec 29, 2011 at 11:51:45AM +0800, Wanlong Gao wrote: > Hi all: > > This is first reported to *libguestfs*: https://bugzilla.redhat.com/show_bug.cgi?id=624335 > > Then, I looked into upstream util-linux and it seems nothing wrong. I'm not convinced that it's a kernel bug. > > produce: > > --- > # ./util-linux/disk-utils/blockdev --getbsz /dev/sda6 > 4096 > # ./util-linux/disk-utils/blockdev --setbsz 2048 /dev/sda6 > # ./util-linux/disk-utils/blockdev --getbsz /dev/sda6 > 4096 > # ./util-linux/disk-utils/blockdev --setbsz 512 /dev/sda6 > # ./util-linux/disk-utils/blockdev --getbsz /dev/sda6 > 4096
I think each blockdev invocation is working on a *new* bdev object. You'll get consistent results if somehow keep it referenced, for example, run a background copy task:
# cp /dev/sda6 /dev/null &
# ./util-linux/disk-utils/blockdev --getbsz /dev/sda6 # ./util-linux/disk-utils/blockdev --setbsz 512 /dev/sda6 # ./util-linux/disk-utils/blockdev --getbsz /dev/sda6
Thanks, Fengguang
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