freeze_bdev9
- lock a filesystem and force it into a consistent state
Usage
struct super_block * freeze_bdev(struct block_device * bdev);
Arguments
bdev
blockdevice to lock
Overview
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.
Releases
6 releases since Debian 4.0 (Etch); the text changed 5 times.