drbd: prepare receiving side for REQ_DISCARD
If the receiver needs to serve a discard request on a queue that does
not announce to be discard cabable, it falls back to do synchronous
blkdev_issue_zeroout().
We expect only "reasonably" large (up to one activity log extent?)
discard requests.
We do this to not to not block the receiver for too long in this
fallback code path, and to not set/clear too many bits inside one
spinlock_irq_save() in drbd_set_in_sync/drbd_set_out_of_sync,
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/drivers/block/drbd/drbd_protocol.h b/drivers/block/drbd/drbd_protocol.h
index 3c04ec0..478c63d 100644
--- a/drivers/block/drbd/drbd_protocol.h
+++ b/drivers/block/drbd/drbd_protocol.h
@@ -54,6 +54,11 @@
P_CONN_ST_CHG_REPLY = 0x2b, /* meta sock: Connection side state req reply */
P_RETRY_WRITE = 0x2c, /* Protocol C: retry conflicting write request */
P_PROTOCOL_UPDATE = 0x2d, /* data sock: is used in established connections */
+ /* 0x2e to 0x30 reserved, used in drbd 9 */
+
+ /* REQ_DISCARD. We used "discard" in different contexts before,
+ * which is why I chose TRIM here, to disambiguate. */
+ P_TRIM = 0x31,
P_MAY_IGNORE = 0x100, /* Flag to test if (cmd > P_MAY_IGNORE) ... */
P_MAX_OPT_CMD = 0x101,
@@ -119,6 +124,11 @@
u32 dp_flags;
} __packed;
+struct p_trim {
+ struct p_data p_data;
+ u32 size; /* == bio->bi_size */
+} __packed;
+
/*
* commands which share a struct:
* p_block_ack: