1JOURNAL_LOCK_UPDATES(9)    The Linux Journalling API   JOURNAL_LOCK_UPDATES(9)
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NAME

6       journal_lock_updates - establish a transaction barrier.
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SYNOPSIS

9       void journal_lock_updates(journal_t * journal);
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ARGUMENTS

12       journal
13           Journal to establish a barrier on.
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DESCRIPTION

16       This locks out any further updates from being started, and blocks until
17       all existing updates have completed, returning only once the journal is
18       in a quiescent state with no updates running.
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20       We do not use simple mutex for synchronization as there are syscalls
21       which want to return with filesystem locked and that trips up lockdep.
22       Also hibernate needs to lock filesystem but locked mutex then blocks
23       hibernation. Since locking filesystem is rare operation, we use simple
24       counter and waitqueue for locking.
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AUTHORS

27       Roger Gammans <rgammans@computer-surgery.co.uk>
28           Author.
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30       Stephen Tweedie <sct@redhat.com>
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34Kernel Hackers Manual 2.6.         June 2019           JOURNAL_LOCK_UPDATES(9)
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