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authorLars Ellenberg <lars.ellenberg@linbit.com>2017-08-29 11:20:38 +0300
committerJens Axboe <axboe@kernel.dk>2017-08-30 00:34:44 +0300
commit9de7e14a1a9c6bc4f9be6ccd9b951341a80dbd52 (patch)
tree5255e73d42a6d601041f1e82056b02da77fe9c8a /include/linux/drbd_limits.h
parentc200d9868707150abd37853cb341b54f75461208 (diff)
downloadlinux-9de7e14a1a9c6bc4f9be6ccd9b951341a80dbd52.tar.xz
drbd: new disk-option disable-write-same
Some backend devices claim to support write-same, but would fail actual write-same requests. Allow to set (or toggle) whether or not DRBD tries to support write-same. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux/drbd_limits.h')
-rw-r--r--include/linux/drbd_limits.h8
1 files changed, 7 insertions, 1 deletions
diff --git a/include/linux/drbd_limits.h b/include/linux/drbd_limits.h
index ddac68422a96..24ae1b9b76c7 100644
--- a/include/linux/drbd_limits.h
+++ b/include/linux/drbd_limits.h
@@ -209,12 +209,18 @@
#define DRBD_MD_FLUSHES_DEF 1
#define DRBD_TCP_CORK_DEF 1
#define DRBD_AL_UPDATES_DEF 1
+
/* We used to ignore the discard_zeroes_data setting.
* To not change established (and expected) behaviour,
* by default assume that, for discard_zeroes_data=0,
* we can make that an effective discard_zeroes_data=1,
* if we only explicitly zero-out unaligned partial chunks. */
-#define DRBD_DISCARD_ZEROES_IF_ALIGNED 1
+#define DRBD_DISCARD_ZEROES_IF_ALIGNED_DEF 1
+
+/* Some backends pretend to support WRITE SAME,
+ * but fail such requests when they are actually submitted.
+ * This is to tell DRBD to not even try. */
+#define DRBD_DISABLE_WRITE_SAME_DEF 0
#define DRBD_ALLOW_TWO_PRIMARIES_DEF 0
#define DRBD_ALWAYS_ASBP_DEF 0