Commit 9d609f85 authored Apr 18, 2017 by Mikulas Patocka Committed by Mike Snitzer Apr 24, 2017

dm integrity: support larger block sizes

The DM integrity block size can now be 512, 1k, 2k or 4k. Using larger
blocks reduces metadata handling overhead. The block size can be
configured at table load time using the "block_size:<value>" option;
where <value> is expressed in bytes (defult is still 512 bytes).

It is safe to use larger block sizes with DM integrity, because the
DM integrity journal makes sure that the whole block is updated
atomically even if the underlying device doesn't support atomic writes
of that size (e.g. 4k block ontop of a 512b device).

Depends-on: 2859323e ("block: fix blk_integrity_register to use template's interval_exp if not 0")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

parent 56b67a4f

Documentation/device-mapper/dm-integrity.txt

+5 −0

Original line number	Diff line number	Diff line
		@@ -136,6 +136,11 @@ journal_mac:algorithm(:key) (the key is optional)
		the journal. Thus, modified sector number would be detected at
		this stage.

		block_size:number
		The size of a data block in bytes. The larger the block size the
		less overhead there is for per-block integrity metadata.
		Supported values are 512, 1024, 2048 and 4096 bytes. If not
		specified the default block size is 512 bytes.

		The journal mode (D/J), buffer_sectors, journal_watermark, commit_time can
		be changed when reloading the target (load an inactive table and swap the

drivers/md/dm-integrity.c

+174 −45

File changed.

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