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authorMikulas Patocka <mpatocka@redhat.com>2019-11-13 14:48:16 +0300
committerMike Snitzer <snitzer@redhat.com>2019-11-15 22:49:16 +0300
commitd537858ac8aaf4311b51240893add2fc62003b97 (patch)
tree7d95a35edc2d838b9a605db8bac62f39c9b1cbb5 /Documentation/admin-guide/device-mapper
parent35ad035b8398c634d888324a299ec50a84cbc6cc (diff)
downloadlinux-d537858ac8aaf4311b51240893add2fc62003b97.tar.xz
dm integrity: fix excessive alignment of metadata runs
Metadata runs are supposed to be aligned on 4k boundary (so that they work efficiently with disks with 4k sectors). However, there was a programming bug that makes them aligned on 128k boundary instead. The unused space is wasted. Fix this bug by providing a proper 4k alignment. In order to keep existing volumes working, we introduce a new flag SB_FLAG_FIXED_PADDING - when the flag is clear, we calculate the padding the old way. In order to make sure that the old version cannot mount the volume created by the new version, we increase superblock version to 4. Also in order to not break with old integritysetup, we fix alignment only if the parameter "fix_padding" is present when formatting the device. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'Documentation/admin-guide/device-mapper')
-rw-r--r--Documentation/admin-guide/device-mapper/dm-integrity.rst5
1 files changed, 5 insertions, 0 deletions
diff --git a/Documentation/admin-guide/device-mapper/dm-integrity.rst b/Documentation/admin-guide/device-mapper/dm-integrity.rst
index a30aa91b5fbe..594095b54b29 100644
--- a/Documentation/admin-guide/device-mapper/dm-integrity.rst
+++ b/Documentation/admin-guide/device-mapper/dm-integrity.rst
@@ -177,6 +177,11 @@ bitmap_flush_interval:number
The bitmap flush interval in milliseconds. The metadata buffers
are synchronized when this interval expires.
+fix_padding
+ Use a smaller padding of the tag area that is more
+ space-efficient. If this option is not present, large padding is
+ used - that is for compatibility with older kernels.
+
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