FREEZE_BDEV(9) The Linux VFS FREEZE_BDEV(9)
NAME
freeze_bdev - - lock a filesystem and force it into a consistent state
SYNOPSIS
struct super_block * freeze_bdev(struct block_device * bdev);
ARGUMENTS
bdev
blockdevice to lock
DESCRIPTION
If a superblock is found on this device, we take the s_umount semaphore on it to make sure nobody unmounts until the snapshot creation is
done. The reference counter (bd_fsfreeze_count) guarantees that only the last unfreeze process can unfreeze the frozen filesystem actually
when multiple freeze requests arrive simultaneously. It counts up in freeze_bdev and count down in thaw_bdev. When it becomes 0, thaw_bdev
will unfreeze actually.
COPYRIGHT
Kernel Hackers Manual 3.10 June 2014 FREEZE_BDEV(9)
