admin-guide/device-mapper/dm-integrity.rst

12 To guarantee write atomicity, the dm-integrity target uses journal, it
13 writes sector data and integrity tags into a journal, commits the journal
29 instead of a journal. If a bit in the bitmap is 1, the corresponding
32 is faster than the journal mode, because we don't have to write the data
66 	D - direct writes (without journal)
73 		journal and atomicity is guaranteed. In case of crash,
81 	R - recovery mode - in this mode, journal is not replayed,
92 	The size of journal, this argument is used only if formatting the
114 	The journal watermark in percents. When the size of the journal
115 	exceeds this watermark, the thread that flushes the journal will
119 	Commit time in milliseconds. When this time passes, the journal is
120 	written. The journal is also written immediatelly if the FLUSH
144 	Encrypt the journal using given algorithm to make sure that the
145 	attacker can't read the journal. You can use a block cipher here
149 	The journal contains history of last writes to the block device,
150 	an attacker reading the journal could see the last sector nubmers
153 	situation, you can encrypt the journal.
156 	Protect sector numbers in the journal from accidental or malicious
162 	mode, the integrity of journal entries is checked when replaying
163 	the journal. Thus, modified sector number would be detected at
195 The journal mode (D/J), buffer_sectors, journal_watermark, commit_time and
222 	* the number of journal sections
233 		- journal area contains the bitmap of dirty
237 * journal
238 	The journal is divided into sections, each section contains:
240 	* metadata area (4kiB), it contains journal entries
242 	  - every journal entry contains:
253 		  numbers in the journal section, to protect against a
255 		  numbers in the journal.
258 	* data area (the size is variable; it depends on how many journal
264 		  the journal entry)
267 	To test if the whole journal section was written correctly, every
268 	512-byte sector of the journal ends with 8-byte commit id. If the
269 	commit id matches on all sectors in a journal section, then it is