BLOCKDEV(8) System Administration BLOCKDEV(8) (NAME) blockdev - ioctl (SYNOPSIS) blockdev [-q] [-v] command [command...] device [device...] blockdev --report [device...] blockdev -h|-V (DESCRIPTION) blockdev ioctl . (OPTIONS) -q ( ). -v ( ). --report . . /proc/partitions . StartSec . -h, --help . -V, --version . (COMMANDS) . --flushbufs . --getalignoff . --getbsz . () ( ) (mount) . --getdiscardzeroes (discard zeroes). --getdiskseq . --getzonesz (zone) . --getfra (readahead) . --getiomin /. --getioopt /. --getmaxsect . --getpbsz (). --getra (readahead) ( ). --getro . 1 0 . --getsize64 . --getsize ( !) . --getsz . --getss - . --getsz . --rereadpt . --setbsz bytes . blockdev blockdev . --setfra sectors (readahead) ( --setra 2.6). --setra sectors (readahead) ( ). --setro . - (mount) . (remount) . --setrw -. (AUTHORS) blockdev Andries E. Brouwer Karel Zak . (REPORTING BUGS) . (AVAILABILITY) blockdev util-linux . . util-linux 2.41.5 2026-06-16 BLOCKDEV(8)