https://unix.stackexchange.com/questions/195010/remount-a-busy-disk-to-read-only-mode

echo u > /proc/sysrq-trigger
 
# paquet util-linux
fsfreeze -f /
fsfreeze -u /
 
echo 1 >/sys/block/dm-4/ro
echo 1 >/sys/block/sda/sda2/ro

# LANG=C fdisk /dev/sdb

Welcome to fdisk (util-linux 2.33.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

fdisk: cannot open /dev/sdb: Read-only file system

# hdparm -r0 /dev/sdb

/dev/sdb:
 setting readonly to 0 (off)
 readonly      =  0 (off)

Voir : https://gist.github.com/cocagne/4088467

losetup

• https://linuxgazette.net/109/chirico.html
• https://elinux.org/RPi_Resize_Flash_Partitions
• https://mike632t.wordpress.com/2014/02/10/resizing-partitions/