Documentation/filesystems/journalling.rst

5 --------
70 jbd2_journal_destroy() to clean up your in-core journal object.
74 single outstanding transaction at any one time, remember nothing commits
77 perform, so that the journalling system isn't re-entered on another
84 on the passed nblocks param) - when it blocks it merely(!) needs to wait
94 Try to reserve the right number of blocks the first time. ;-). This will
99 Another wriggle to watch out for is your on-disk block allocation
102 these blocks commits. If you reused these blocks and crash happens,
105 this is to mark blocks as free in internal in-memory block allocation
106 structures only after the transaction freeing them commits. Ext4 uses
113 ``journal->j_commit_callback`` function pointer and that function is
133 Fast commits
136 JBD2 to also allows you to perform file-system specific delta commits known as
137 fast commits. In order to use fast commits, you will need to set following
140 `journal->j_fc_cleanup_cb`: Cleanup function called after every full commit and
143 `journal->j_fc_replay_cb`: Replay function called for replay of fast commit
146 File system is free to perform fast commits as and when it wants as long as it
160 Currently, only Ext4 implements fast commits. For details of its implementation
161 of fast commits, please refer to the top level comments in
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182 .. kernel-doc:: include/linux/jbd2.h
186 ---------
194 .. kernel-doc:: fs/jbd2/journal.c
197 .. kernel-doc:: fs/jbd2/recovery.c
203 .. kernel-doc:: fs/jbd2/transaction.c
206 --------
209 Tweedie <http://kernel.org/pub/linux/kernel/people/sct/ext3/journal-design.ps.gz>`__
212 Tweedie <http://olstrans.sourceforge.net/release/OLS2000-ext3/OLS2000-ext3.html>`__