1FREEZE_BDEV(9)                   The Linux VFS                  FREEZE_BDEV(9)
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NAME

6       freeze_bdev - - lock a filesystem and force it into a consistent state
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SYNOPSIS

9       struct super_block * freeze_bdev(struct block_device * bdev);
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ARGUMENTS

12       bdev
13           blockdevice to lock
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DESCRIPTION

16       If a superblock is found on this device, we take the s_umount semaphore
17       on it to make sure nobody unmounts until the snapshot creation is done.
18       The reference counter (bd_fsfreeze_count) guarantees that only the last
19       unfreeze process can unfreeze the frozen filesystem actually when
20       multiple freeze requests arrive simultaneously. It counts up in
21       freeze_bdev and count down in thaw_bdev. When it becomes 0, thaw_bdev
22       will unfreeze actually.
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25Kernel Hackers Manual 3.10         June 2019                    FREEZE_BDEV(9)
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