drbd: introduce WRITE_SAME support
authorLars Ellenberg <lars@linbit.com>
Mon, 13 Jun 2016 22:26:31 +0000 (00:26 +0200)
committerJens Axboe <axboe@fb.com>
Tue, 14 Jun 2016 03:43:07 +0000 (21:43 -0600)
We will support WRITE_SAME, if
 * all peers support WRITE_SAME (both in kernel and DRBD version),
 * all peer devices support WRITE_SAME
 * logical_block_size is identical on all peers.

We may at some point introduce a fallback on the receiving side
for devices/kernels that do not support WRITE_SAME,
by open-coding a submit loop. But not yet.

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>
drivers/block/drbd/drbd_actlog.c
drivers/block/drbd/drbd_debugfs.c
drivers/block/drbd/drbd_int.h
drivers/block/drbd/drbd_main.c
drivers/block/drbd/drbd_nl.c
drivers/block/drbd/drbd_protocol.h
drivers/block/drbd/drbd_receiver.c
drivers/block/drbd/drbd_req.c
drivers/block/drbd/drbd_req.h
drivers/block/drbd/drbd_worker.c

index cafa9c4..f9af555 100644 (file)
@@ -840,6 +840,13 @@ static int update_sync_bits(struct drbd_device *device,
        return count;
 }
 
+static bool plausible_request_size(int size)
+{
+       return size > 0
+               && size <= DRBD_MAX_BATCH_BIO_SIZE
+               && IS_ALIGNED(size, 512);
+}
+
 /* clear the bit corresponding to the piece of storage in question:
  * size byte of data starting from sector.  Only clear a bits of the affected
  * one ore more _aligned_ BM_BLOCK_SIZE blocks.
@@ -859,7 +866,7 @@ int __drbd_change_sync(struct drbd_device *device, sector_t sector, int size,
        if ((mode == SET_OUT_OF_SYNC) && size == 0)
                return 0;
 
-       if (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_DISCARD_SIZE) {
+       if (!plausible_request_size(size)) {
                drbd_err(device, "%s: sector=%llus size=%d nonsense!\n",
                                drbd_change_sync_fname[mode],
                                (unsigned long long)sector, size);
index 4de95bb..8a90812 100644 (file)
@@ -237,14 +237,9 @@ static void seq_print_peer_request_flags(struct seq_file *m, struct drbd_peer_re
        seq_print_rq_state_bit(m, f & EE_SEND_WRITE_ACK, &sep, "C");
        seq_print_rq_state_bit(m, f & EE_MAY_SET_IN_SYNC, &sep, "set-in-sync");
 
-       if (f & EE_IS_TRIM) {
-               seq_putc(m, sep);
-               sep = '|';
-               if (f & EE_IS_TRIM_USE_ZEROOUT)
-                       seq_puts(m, "zero-out");
-               else
-                       seq_puts(m, "trim");
-       }
+       if (f & EE_IS_TRIM)
+               __seq_print_rq_state_bit(m, f & EE_IS_TRIM_USE_ZEROOUT, &sep, "zero-out", "trim");
+       seq_print_rq_state_bit(m, f & EE_WRITE_SAME, &sep, "write-same");
        seq_putc(m, '\n');
 }
 
index 5ee8da3..995aa8d 100644 (file)
@@ -468,6 +468,9 @@ enum {
        /* this is/was a write request */
        __EE_WRITE,
 
+       /* this is/was a write same request */
+       __EE_WRITE_SAME,
+
        /* this originates from application on peer
         * (not some resync or verify or other DRBD internal request) */
        __EE_APPLICATION,
@@ -487,6 +490,7 @@ enum {
 #define EE_IN_INTERVAL_TREE    (1<<__EE_IN_INTERVAL_TREE)
 #define EE_SUBMITTED           (1<<__EE_SUBMITTED)
 #define EE_WRITE               (1<<__EE_WRITE)
+#define EE_WRITE_SAME          (1<<__EE_WRITE_SAME)
 #define EE_APPLICATION         (1<<__EE_APPLICATION)
 #define EE_RS_THIN_REQ         (1<<__EE_RS_THIN_REQ)
 
@@ -1350,8 +1354,8 @@ struct bm_extent {
 /* For now, don't allow more than half of what we can "activate" in one
  * activity log transaction to be discarded in one go. We may need to rework
  * drbd_al_begin_io() to allow for even larger discard ranges */
-#define DRBD_MAX_DISCARD_SIZE  (AL_UPDATES_PER_TRANSACTION/2*AL_EXTENT_SIZE)
-#define DRBD_MAX_DISCARD_SECTORS (DRBD_MAX_DISCARD_SIZE >> 9)
+#define DRBD_MAX_BATCH_BIO_SIZE         (AL_UPDATES_PER_TRANSACTION/2*AL_EXTENT_SIZE)
+#define DRBD_MAX_BBIO_SECTORS    (DRBD_MAX_BATCH_BIO_SIZE >> 9)
 
 extern int  drbd_bm_init(struct drbd_device *device);
 extern int  drbd_bm_resize(struct drbd_device *device, sector_t sectors, int set_new_bits);
@@ -1488,7 +1492,8 @@ enum determine_dev_size {
 extern enum determine_dev_size
 drbd_determine_dev_size(struct drbd_device *, enum dds_flags, struct resize_parms *) __must_hold(local);
 extern void resync_after_online_grow(struct drbd_device *);
-extern void drbd_reconsider_queue_parameters(struct drbd_device *device, struct drbd_backing_dev *bdev);
+extern void drbd_reconsider_queue_parameters(struct drbd_device *device,
+                       struct drbd_backing_dev *bdev, struct o_qlim *o);
 extern enum drbd_state_rv drbd_set_role(struct drbd_device *device,
                                        enum drbd_role new_role,
                                        int force);
@@ -1569,7 +1574,7 @@ extern int drbd_submit_peer_request(struct drbd_device *,
 extern int drbd_free_peer_reqs(struct drbd_device *, struct list_head *);
 extern struct drbd_peer_request *drbd_alloc_peer_req(struct drbd_peer_device *, u64,
                                                     sector_t, unsigned int,
-                                                    bool,
+                                                    unsigned int,
                                                     gfp_t) __must_hold(local);
 extern void __drbd_free_peer_req(struct drbd_device *, struct drbd_peer_request *,
                                 int);
index 64e9525..f4ea8d6 100644 (file)
@@ -920,6 +920,31 @@ void drbd_gen_and_send_sync_uuid(struct drbd_peer_device *peer_device)
        }
 }
 
+/* communicated if (agreed_features & DRBD_FF_WSAME) */
+void assign_p_sizes_qlim(struct drbd_device *device, struct p_sizes *p, struct request_queue *q)
+{
+       if (q) {
+               p->qlim->physical_block_size = cpu_to_be32(queue_physical_block_size(q));
+               p->qlim->logical_block_size = cpu_to_be32(queue_logical_block_size(q));
+               p->qlim->alignment_offset = cpu_to_be32(queue_alignment_offset(q));
+               p->qlim->io_min = cpu_to_be32(queue_io_min(q));
+               p->qlim->io_opt = cpu_to_be32(queue_io_opt(q));
+               p->qlim->discard_enabled = blk_queue_discard(q);
+               p->qlim->discard_zeroes_data = queue_discard_zeroes_data(q);
+               p->qlim->write_same_capable = !!q->limits.max_write_same_sectors;
+       } else {
+               q = device->rq_queue;
+               p->qlim->physical_block_size = cpu_to_be32(queue_physical_block_size(q));
+               p->qlim->logical_block_size = cpu_to_be32(queue_logical_block_size(q));
+               p->qlim->alignment_offset = 0;
+               p->qlim->io_min = cpu_to_be32(queue_io_min(q));
+               p->qlim->io_opt = cpu_to_be32(queue_io_opt(q));
+               p->qlim->discard_enabled = 0;
+               p->qlim->discard_zeroes_data = 0;
+               p->qlim->write_same_capable = 0;
+       }
+}
+
 int drbd_send_sizes(struct drbd_peer_device *peer_device, int trigger_reply, enum dds_flags flags)
 {
        struct drbd_device *device = peer_device->device;
@@ -928,29 +953,37 @@ int drbd_send_sizes(struct drbd_peer_device *peer_device, int trigger_reply, enu
        sector_t d_size, u_size;
        int q_order_type;
        unsigned int max_bio_size;
+       unsigned int packet_size;
+
+       sock = &peer_device->connection->data;
+       p = drbd_prepare_command(peer_device, sock);
+       if (!p)
+               return -EIO;
 
+       packet_size = sizeof(*p);
+       if (peer_device->connection->agreed_features & DRBD_FF_WSAME)
+               packet_size += sizeof(p->qlim[0]);
+
+       memset(p, 0, packet_size);
        if (get_ldev_if_state(device, D_NEGOTIATING)) {
-               D_ASSERT(device, device->ldev->backing_bdev);
+               struct request_queue *q = bdev_get_queue(device->ldev->backing_bdev);
                d_size = drbd_get_max_capacity(device->ldev);
                rcu_read_lock();
                u_size = rcu_dereference(device->ldev->disk_conf)->disk_size;
                rcu_read_unlock();
                q_order_type = drbd_queue_order_type(device);
-               max_bio_size = queue_max_hw_sectors(device->ldev->backing_bdev->bd_disk->queue) << 9;
+               max_bio_size = queue_max_hw_sectors(q) << 9;
                max_bio_size = min(max_bio_size, DRBD_MAX_BIO_SIZE);
+               assign_p_sizes_qlim(device, p, q);
                put_ldev(device);
        } else {
                d_size = 0;
                u_size = 0;
                q_order_type = QUEUE_ORDERED_NONE;
                max_bio_size = DRBD_MAX_BIO_SIZE; /* ... multiple BIOs per peer_request */
+               assign_p_sizes_qlim(device, p, NULL);
        }
 
-       sock = &peer_device->connection->data;
-       p = drbd_prepare_command(peer_device, sock);
-       if (!p)
-               return -EIO;
-
        if (peer_device->connection->agreed_pro_version <= 94)
                max_bio_size = min(max_bio_size, DRBD_MAX_SIZE_H80_PACKET);
        else if (peer_device->connection->agreed_pro_version < 100)
@@ -962,7 +995,8 @@ int drbd_send_sizes(struct drbd_peer_device *peer_device, int trigger_reply, enu
        p->max_bio_size = cpu_to_be32(max_bio_size);
        p->queue_order_type = cpu_to_be16(q_order_type);
        p->dds_flags = cpu_to_be16(flags);
-       return drbd_send_command(peer_device, sock, P_SIZES, sizeof(*p), NULL, 0);
+
+       return drbd_send_command(peer_device, sock, P_SIZES, packet_size, NULL, 0);
 }
 
 /**
@@ -1577,6 +1611,9 @@ static int _drbd_send_bio(struct drbd_peer_device *peer_device, struct bio *bio)
                                         ? 0 : MSG_MORE);
                if (err)
                        return err;
+               /* REQ_OP_WRITE_SAME has only one segment */
+               if (bio_op(bio) == REQ_OP_WRITE_SAME)
+                       break;
        }
        return 0;
 }
@@ -1595,6 +1632,9 @@ static int _drbd_send_zc_bio(struct drbd_peer_device *peer_device, struct bio *b
                                      bio_iter_last(bvec, iter) ? 0 : MSG_MORE);
                if (err)
                        return err;
+               /* REQ_OP_WRITE_SAME has only one segment */
+               if (bio_op(bio) == REQ_OP_WRITE_SAME)
+                       break;
        }
        return 0;
 }
@@ -1626,6 +1666,7 @@ static u32 bio_flags_to_wire(struct drbd_connection *connection,
                return  (bio->bi_rw & REQ_SYNC ? DP_RW_SYNC : 0) |
                        (bio->bi_rw & REQ_FUA ? DP_FUA : 0) |
                        (bio->bi_rw & REQ_PREFLUSH ? DP_FLUSH : 0) |
+                       (bio_op(bio) == REQ_OP_WRITE_SAME ? DP_WSAME : 0) |
                        (bio_op(bio) == REQ_OP_DISCARD ? DP_DISCARD : 0);
        else
                return bio->bi_rw & REQ_SYNC ? DP_RW_SYNC : 0;
@@ -1639,6 +1680,8 @@ int drbd_send_dblock(struct drbd_peer_device *peer_device, struct drbd_request *
        struct drbd_device *device = peer_device->device;
        struct drbd_socket *sock;
        struct p_data *p;
+       struct p_wsame *wsame = NULL;
+       void *digest_out;
        unsigned int dp_flags = 0;
        int digest_size;
        int err;
@@ -1674,12 +1717,29 @@ int drbd_send_dblock(struct drbd_peer_device *peer_device, struct drbd_request *
                err = __send_command(peer_device->connection, device->vnr, sock, P_TRIM, sizeof(*t), NULL, 0);
                goto out;
        }
+       if (dp_flags & DP_WSAME) {
+               /* this will only work if DRBD_FF_WSAME is set AND the
+                * handshake agreed that all nodes and backend devices are
+                * WRITE_SAME capable and agree on logical_block_size */
+               wsame = (struct p_wsame*)p;
+               digest_out = wsame + 1;
+               wsame->size = cpu_to_be32(req->i.size);
+       } else
+               digest_out = p + 1;
 
        /* our digest is still only over the payload.
         * TRIM does not carry any payload. */
        if (digest_size)
-               drbd_csum_bio(peer_device->connection->integrity_tfm, req->master_bio, p + 1);
-       err = __send_command(peer_device->connection, device->vnr, sock, P_DATA, sizeof(*p) + digest_size, NULL, req->i.size);
+               drbd_csum_bio(peer_device->connection->integrity_tfm, req->master_bio, digest_out);
+       if (wsame) {
+               err =
+                   __send_command(peer_device->connection, device->vnr, sock, P_WSAME,
+                                  sizeof(*wsame) + digest_size, NULL,
+                                  bio_iovec(req->master_bio).bv_len);
+       } else
+               err =
+                   __send_command(peer_device->connection, device->vnr, sock, P_DATA,
+                                  sizeof(*p) + digest_size, NULL, req->i.size);
        if (!err) {
                /* For protocol A, we have to memcpy the payload into
                 * socket buffers, as we may complete right away
@@ -3660,6 +3720,8 @@ const char *cmdname(enum drbd_packet cmd)
         * one PRO_VERSION */
        static const char *cmdnames[] = {
                [P_DATA]                = "Data",
+               [P_WSAME]               = "WriteSame",
+               [P_TRIM]                = "Trim",
                [P_DATA_REPLY]          = "DataReply",
                [P_RS_DATA_REPLY]       = "RSDataReply",
                [P_BARRIER]             = "Barrier",
index 169e3e1..9a45c80 100644 (file)
@@ -1174,6 +1174,17 @@ static void blk_queue_discard_granularity(struct request_queue *q, unsigned int
 {
        q->limits.discard_granularity = granularity;
 }
+
+static unsigned int drbd_max_discard_sectors(struct drbd_connection *connection)
+{
+       /* when we introduced REQ_WRITE_SAME support, we also bumped
+        * our maximum supported batch bio size used for discards. */
+       if (connection->agreed_features & DRBD_FF_WSAME)
+               return DRBD_MAX_BBIO_SECTORS;
+       /* before, with DRBD <= 8.4.6, we only allowed up to one AL_EXTENT_SIZE. */
+       return AL_EXTENT_SIZE >> 9;
+}
+
 static void decide_on_discard_support(struct drbd_device *device,
                        struct request_queue *q,
                        struct request_queue *b,
@@ -1190,7 +1201,7 @@ static void decide_on_discard_support(struct drbd_device *device,
                can_do = false;
                drbd_info(device, "discard_zeroes_data=0 and discard_zeroes_if_aligned=no: disabling discards\n");
        }
-       if (can_do && connection->cstate >= C_CONNECTED && !(connection->agreed_features & FF_TRIM)) {
+       if (can_do && connection->cstate >= C_CONNECTED && !(connection->agreed_features & DRBD_FF_TRIM)) {
                can_do = false;
                drbd_info(connection, "peer DRBD too old, does not support TRIM: disabling discards\n");
        }
@@ -1202,7 +1213,7 @@ static void decide_on_discard_support(struct drbd_device *device,
                 * you care, you need to use devices with similar
                 * topology on all peers. */
                blk_queue_discard_granularity(q, 512);
-               q->limits.max_discard_sectors = DRBD_MAX_DISCARD_SECTORS;
+               q->limits.max_discard_sectors = drbd_max_discard_sectors(connection);
                queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
        } else {
                queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
@@ -1223,8 +1234,67 @@ static void fixup_discard_if_not_supported(struct request_queue *q)
        }
 }
 
+static void decide_on_write_same_support(struct drbd_device *device,
+                       struct request_queue *q,
+                       struct request_queue *b, struct o_qlim *o)
+{
+       struct drbd_peer_device *peer_device = first_peer_device(device);
+       struct drbd_connection *connection = peer_device->connection;
+       bool can_do = b ? b->limits.max_write_same_sectors : true;
+
+       if (can_do && connection->cstate >= C_CONNECTED && !(connection->agreed_features & DRBD_FF_WSAME)) {
+               can_do = false;
+               drbd_info(peer_device, "peer does not support WRITE_SAME\n");
+       }
+
+       if (o) {
+               /* logical block size; queue_logical_block_size(NULL) is 512 */
+               unsigned int peer_lbs = be32_to_cpu(o->logical_block_size);
+               unsigned int me_lbs_b = queue_logical_block_size(b);
+               unsigned int me_lbs = queue_logical_block_size(q);
+
+               if (me_lbs_b != me_lbs) {
+                       drbd_warn(device,
+                               "logical block size of local backend does not match (drbd:%u, backend:%u); was this a late attach?\n",
+                               me_lbs, me_lbs_b);
+                       /* rather disable write same than trigger some BUG_ON later in the scsi layer. */
+                       can_do = false;
+               }
+               if (me_lbs_b != peer_lbs) {
+                       drbd_warn(peer_device, "logical block sizes do not match (me:%u, peer:%u); this may cause problems.\n",
+                               me_lbs, peer_lbs);
+                       if (can_do) {
+                               drbd_dbg(peer_device, "logical block size mismatch: WRITE_SAME disabled.\n");
+                               can_do = false;
+                       }
+                       me_lbs = max(me_lbs, me_lbs_b);
+                       /* We cannot change the logical block size of an in-use queue.
+                        * We can only hope that access happens to be properly aligned.
+                        * If not, the peer will likely produce an IO error, and detach. */
+                       if (peer_lbs > me_lbs) {
+                               if (device->state.role != R_PRIMARY) {
+                                       blk_queue_logical_block_size(q, peer_lbs);
+                                       drbd_warn(peer_device, "logical block size set to %u\n", peer_lbs);
+                               } else {
+                                       drbd_warn(peer_device,
+                                               "current Primary must NOT adjust logical block size (%u -> %u); hope for the best.\n",
+                                               me_lbs, peer_lbs);
+                               }
+                       }
+               }
+               if (can_do && !o->write_same_capable) {
+                       /* If we introduce an open-coded write-same loop on the receiving side,
+                        * the peer would present itself as "capable". */
+                       drbd_dbg(peer_device, "WRITE_SAME disabled (peer device not capable)\n");
+                       can_do = false;
+               }
+       }
+
+       blk_queue_max_write_same_sectors(q, can_do ? DRBD_MAX_BBIO_SECTORS : 0);
+}
+
 static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backing_dev *bdev,
-                                  unsigned int max_bio_size)
+                                  unsigned int max_bio_size, struct o_qlim *o)
 {
        struct request_queue * const q = device->rq_queue;
        unsigned int max_hw_sectors = max_bio_size >> 9;
@@ -1244,15 +1314,15 @@ static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backi
                rcu_read_unlock();
 
                blk_set_stacking_limits(&q->limits);
-               blk_queue_max_write_same_sectors(q, 0);
        }
 
-       blk_queue_logical_block_size(q, 512);
        blk_queue_max_hw_sectors(q, max_hw_sectors);
        /* This is the workaround for "bio would need to, but cannot, be split" */
        blk_queue_max_segments(q, max_segments ? max_segments : BLK_MAX_SEGMENTS);
        blk_queue_segment_boundary(q, PAGE_SIZE-1);
        decide_on_discard_support(device, q, b, discard_zeroes_if_aligned);
+       decide_on_write_same_support(device, q, b, o);
+
        if (b) {
                blk_queue_stack_limits(q, b);
 
@@ -1266,7 +1336,7 @@ static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backi
        fixup_discard_if_not_supported(q);
 }
 
-void drbd_reconsider_queue_parameters(struct drbd_device *device, struct drbd_backing_dev *bdev)
+void drbd_reconsider_queue_parameters(struct drbd_device *device, struct drbd_backing_dev *bdev, struct o_qlim *o)
 {
        unsigned int now, new, local, peer;
 
@@ -1309,7 +1379,7 @@ void drbd_reconsider_queue_parameters(struct drbd_device *device, struct drbd_ba
        if (new != now)
                drbd_info(device, "max BIO size = %u\n", new);
 
-       drbd_setup_queue_param(device, bdev, new);
+       drbd_setup_queue_param(device, bdev, new, o);
 }
 
 /* Starts the worker thread */
@@ -1542,7 +1612,7 @@ int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info)
                drbd_bump_write_ordering(device->resource, NULL, WO_BDEV_FLUSH);
 
        if (old_disk_conf->discard_zeroes_if_aligned != new_disk_conf->discard_zeroes_if_aligned)
-               drbd_reconsider_queue_parameters(device, device->ldev);
+               drbd_reconsider_queue_parameters(device, device->ldev, NULL);
 
        drbd_md_sync(device);
 
@@ -1922,7 +1992,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info)
        device->read_cnt = 0;
        device->writ_cnt = 0;
 
-       drbd_reconsider_queue_parameters(device, device->ldev);
+       drbd_reconsider_queue_parameters(device, device->ldev, NULL);
 
        /* If I am currently not R_PRIMARY,
         * but meta data primary indicator is set,
index 95ca458..4d29680 100644 (file)
@@ -64,6 +64,11 @@ enum drbd_packet {
        P_RS_THIN_REQ         = 0x32, /* Request a block for resync or reply P_RS_DEALLOCATED */
        P_RS_DEALLOCATED      = 0x33, /* Contains only zeros on sync source node */
 
+       /* REQ_WRITE_SAME.
+        * On a receiving side without REQ_WRITE_SAME,
+        * we may fall back to an opencoded loop instead. */
+       P_WSAME               = 0x34,
+
        P_MAY_IGNORE          = 0x100, /* Flag to test if (cmd > P_MAY_IGNORE) ... */
        P_MAX_OPT_CMD         = 0x101,
 
@@ -110,8 +115,11 @@ struct p_header100 {
        u32       pad;
 } __packed;
 
-/* these defines must not be changed without changing the protocol version */
-#define DP_HARDBARRIER       1 /* depricated */
+/* These defines must not be changed without changing the protocol version.
+ * New defines may only be introduced together with protocol version bump or
+ * new protocol feature flags.
+ */
+#define DP_HARDBARRIER       1 /* no longer used */
 #define DP_RW_SYNC           2 /* equals REQ_SYNC    */
 #define DP_MAY_SET_IN_SYNC    4
 #define DP_UNPLUG             8 /* not used anymore   */
@@ -120,6 +128,7 @@ struct p_header100 {
 #define DP_DISCARD           64 /* equals REQ_DISCARD */
 #define DP_SEND_RECEIVE_ACK 128 /* This is a proto B write request */
 #define DP_SEND_WRITE_ACK   256 /* This is a proto C write request */
+#define DP_WSAME            512 /* equiv. REQ_WRITE_SAME */
 
 struct p_data {
        u64         sector;    /* 64 bits sector number */
@@ -133,6 +142,11 @@ struct p_trim {
        u32         size;       /* == bio->bi_size */
 } __packed;
 
+struct p_wsame {
+       struct p_data p_data;
+       u32           size;     /* == bio->bi_size */
+} __packed;
+
 /*
  * commands which share a struct:
  *  p_block_ack:
@@ -164,8 +178,23 @@ struct p_block_req {
  *   ReportParams
  */
 
-#define FF_TRIM      1
-#define FF_THIN_RESYNC 2
+/* supports TRIM/DISCARD on the "wire" protocol */
+#define DRBD_FF_TRIM 1
+
+/* Detect all-zeros during resync, and rather TRIM/UNMAP/DISCARD those blocks
+ * instead of fully allocate a supposedly thin volume on initial resync */
+#define DRBD_FF_THIN_RESYNC 2
+
+/* supports REQ_WRITE_SAME on the "wire" protocol.
+ * Note: this flag is overloaded,
+ * its presence also
+ *   - indicates support for 128 MiB "batch bios",
+ *     max discard size of 128 MiB
+ *     instead of 4M before that.
+ *   - indicates that we exchange additional settings in p_sizes
+ *     drbd_send_sizes()/receive_sizes()
+ */
+#define DRBD_FF_WSAME 4
 
 struct p_connection_features {
        u32 protocol_min;
@@ -240,6 +269,40 @@ struct p_rs_uuid {
        u64         uuid;
 } __packed;
 
+/* optional queue_limits if (agreed_features & DRBD_FF_WSAME)
+ * see also struct queue_limits, as of late 2015 */
+struct o_qlim {
+       /* we don't need it yet, but we may as well communicate it now */
+       u32 physical_block_size;
+
+       /* so the original in struct queue_limits is unsigned short,
+        * but I'd have to put in padding anyways. */
+       u32 logical_block_size;
+
+       /* One incoming bio becomes one DRBD request,
+        * which may be translated to several bio on the receiving side.
+        * We don't need to communicate chunk/boundary/segment ... limits.
+        */
+
+       /* various IO hints may be useful with "diskless client" setups */
+       u32 alignment_offset;
+       u32 io_min;
+       u32 io_opt;
+
+       /* We may need to communicate integrity stuff at some point,
+        * but let's not get ahead of ourselves. */
+
+       /* Backend discard capabilities.
+        * Receiving side uses "blkdev_issue_discard()", no need to communicate
+        * more specifics.  If the backend cannot do discards, the DRBD peer
+        * may fall back to blkdev_issue_zeroout().
+        */
+       u8 discard_enabled;
+       u8 discard_zeroes_data;
+       u8 write_same_capable;
+       u8 _pad;
+} __packed;
+
 struct p_sizes {
        u64         d_size;  /* size of disk */
        u64         u_size;  /* user requested size */
@@ -247,6 +310,9 @@ struct p_sizes {
        u32         max_bio_size;  /* Maximal size of a BIO */
        u16         queue_order_type;  /* not yet implemented in DRBD*/
        u16         dds_flags; /* use enum dds_flags here. */
+
+       /* optional queue_limits if (agreed_features & DRBD_FF_WSAME) */
+       struct o_qlim qlim[0];
 } __packed;
 
 struct p_state {
index 367b8e9..b25600e 100644 (file)
@@ -48,7 +48,7 @@
 #include "drbd_req.h"
 #include "drbd_vli.h"
 
-#define PRO_FEATURES (FF_TRIM | FF_THIN_RESYNC)
+#define PRO_FEATURES (DRBD_FF_TRIM|DRBD_FF_THIN_RESYNC|DRBD_FF_WSAME)
 
 struct packet_info {
        enum drbd_packet cmd;
@@ -361,14 +361,17 @@ You must not have the req_lock:
  drbd_wait_ee_list_empty()
 */
 
+/* normal: payload_size == request size (bi_size)
+ * w_same: payload_size == logical_block_size
+ * trim: payload_size == 0 */
 struct drbd_peer_request *
 drbd_alloc_peer_req(struct drbd_peer_device *peer_device, u64 id, sector_t sector,
-                   unsigned int data_size, bool has_payload, gfp_t gfp_mask) __must_hold(local)
+                   unsigned int request_size, unsigned int payload_size, gfp_t gfp_mask) __must_hold(local)
 {
        struct drbd_device *device = peer_device->device;
        struct drbd_peer_request *peer_req;
        struct page *page = NULL;
-       unsigned nr_pages = (data_size + PAGE_SIZE -1) >> PAGE_SHIFT;
+       unsigned nr_pages = (payload_size + PAGE_SIZE -1) >> PAGE_SHIFT;
 
        if (drbd_insert_fault(device, DRBD_FAULT_AL_EE))
                return NULL;
@@ -380,7 +383,7 @@ drbd_alloc_peer_req(struct drbd_peer_device *peer_device, u64 id, sector_t secto
                return NULL;
        }
 
-       if (has_payload && data_size) {
+       if (nr_pages) {
                page = drbd_alloc_pages(peer_device, nr_pages,
                                        gfpflags_allow_blocking(gfp_mask));
                if (!page)
@@ -390,7 +393,7 @@ drbd_alloc_peer_req(struct drbd_peer_device *peer_device, u64 id, sector_t secto
        memset(peer_req, 0, sizeof(*peer_req));
        INIT_LIST_HEAD(&peer_req->w.list);
        drbd_clear_interval(&peer_req->i);
-       peer_req->i.size = data_size;
+       peer_req->i.size = request_size;
        peer_req->i.sector = sector;
        peer_req->submit_jif = jiffies;
        peer_req->peer_device = peer_device;
@@ -1530,7 +1533,7 @@ static bool can_do_reliable_discards(struct drbd_device *device)
        return can_do;
 }
 
-void drbd_issue_peer_discard(struct drbd_device *device, struct drbd_peer_request *peer_req)
+static void drbd_issue_peer_discard(struct drbd_device *device, struct drbd_peer_request *peer_req)
 {
        /* If the backend cannot discard, or does not guarantee
         * read-back zeroes in discarded ranges, we fall back to
@@ -1545,6 +1548,18 @@ void drbd_issue_peer_discard(struct drbd_device *device, struct drbd_peer_reques
        drbd_endio_write_sec_final(peer_req);
 }
 
+static void drbd_issue_peer_wsame(struct drbd_device *device,
+                                 struct drbd_peer_request *peer_req)
+{
+       struct block_device *bdev = device->ldev->backing_bdev;
+       sector_t s = peer_req->i.sector;
+       sector_t nr = peer_req->i.size >> 9;
+       if (blkdev_issue_write_same(bdev, s, nr, GFP_NOIO, peer_req->pages))
+               peer_req->flags |= EE_WAS_ERROR;
+       drbd_endio_write_sec_final(peer_req);
+}
+
+
 /**
  * drbd_submit_peer_request()
  * @device:    DRBD device.
@@ -1582,7 +1597,7 @@ int drbd_submit_peer_request(struct drbd_device *device,
         * Correctness first, performance later.  Next step is to code an
         * asynchronous variant of the same.
         */
-       if (peer_req->flags & EE_IS_TRIM) {
+       if (peer_req->flags & (EE_IS_TRIM|EE_WRITE_SAME)) {
                /* wait for all pending IO completions, before we start
                 * zeroing things out. */
                conn_wait_active_ee_empty(peer_req->peer_device->connection);
@@ -1599,7 +1614,10 @@ int drbd_submit_peer_request(struct drbd_device *device,
                        spin_unlock_irq(&device->resource->req_lock);
                }
 
-               drbd_issue_peer_discard(device, peer_req);
+               if (peer_req->flags & EE_IS_TRIM)
+                       drbd_issue_peer_discard(device, peer_req);
+               else /* EE_WRITE_SAME */
+                       drbd_issue_peer_wsame(device, peer_req);
                return 0;
        }
 
@@ -1772,8 +1790,26 @@ static int receive_Barrier(struct drbd_connection *connection, struct packet_inf
        return 0;
 }
 
+/* quick wrapper in case payload size != request_size (write same) */
+static void drbd_csum_ee_size(struct crypto_ahash *h,
+                             struct drbd_peer_request *r, void *d,
+                             unsigned int payload_size)
+{
+       unsigned int tmp = r->i.size;
+       r->i.size = payload_size;
+       drbd_csum_ee(h, r, d);
+       r->i.size = tmp;
+}
+
 /* used from receive_RSDataReply (recv_resync_read)
- * and from receive_Data */
+ * and from receive_Data.
+ * data_size: actual payload ("data in")
+ *     for normal writes that is bi_size.
+ *     for discards, that is zero.
+ *     for write same, it is logical_block_size.
+ * both trim and write same have the bi_size ("data len to be affected")
+ * as extra argument in the packet header.
+ */
 static struct drbd_peer_request *
 read_in_block(struct drbd_peer_device *peer_device, u64 id, sector_t sector,
              struct packet_info *pi) __must_hold(local)
@@ -1788,6 +1824,7 @@ read_in_block(struct drbd_peer_device *peer_device, u64 id, sector_t sector,
        void *dig_vv = peer_device->connection->int_dig_vv;
        unsigned long *data;
        struct p_trim *trim = (pi->cmd == P_TRIM) ? pi->data : NULL;
+       struct p_trim *wsame = (pi->cmd == P_WSAME) ? pi->data : NULL;
 
        digest_size = 0;
        if (!trim && peer_device->connection->peer_integrity_tfm) {
@@ -1802,38 +1839,60 @@ read_in_block(struct drbd_peer_device *peer_device, u64 id, sector_t sector,
                data_size -= digest_size;
        }
 
+       /* assume request_size == data_size, but special case trim and wsame. */
+       ds = data_size;
        if (trim) {
-               D_ASSERT(peer_device, data_size == 0);
-               data_size = be32_to_cpu(trim->size);
+               if (!expect(data_size == 0))
+                       return NULL;
+               ds = be32_to_cpu(trim->size);
+       } else if (wsame) {
+               if (data_size != queue_logical_block_size(device->rq_queue)) {
+                       drbd_err(peer_device, "data size (%u) != drbd logical block size (%u)\n",
+                               data_size, queue_logical_block_size(device->rq_queue));
+                       return NULL;
+               }
+               if (data_size != bdev_logical_block_size(device->ldev->backing_bdev)) {
+                       drbd_err(peer_device, "data size (%u) != backend logical block size (%u)\n",
+                               data_size, bdev_logical_block_size(device->ldev->backing_bdev));
+                       return NULL;
+               }
+               ds = be32_to_cpu(wsame->size);
        }
 
-       if (!expect(IS_ALIGNED(data_size, 512)))
+       if (!expect(IS_ALIGNED(ds, 512)))
                return NULL;
-       /* prepare for larger trim requests. */
-       if (!trim && !expect(data_size <= DRBD_MAX_BIO_SIZE))
+       if (trim || wsame) {
+               if (!expect(ds <= (DRBD_MAX_BBIO_SECTORS << 9)))
+                       return NULL;
+       } else if (!expect(ds <= DRBD_MAX_BIO_SIZE))
                return NULL;
 
        /* even though we trust out peer,
         * we sometimes have to double check. */
-       if (sector + (data_size>>9) > capacity) {
+       if (sector + (ds>>9) > capacity) {
                drbd_err(device, "request from peer beyond end of local disk: "
                        "capacity: %llus < sector: %llus + size: %u\n",
                        (unsigned long long)capacity,
-                       (unsigned long long)sector, data_size);
+                       (unsigned long long)sector, ds);
                return NULL;
        }
 
        /* GFP_NOIO, because we must not cause arbitrary write-out: in a DRBD
         * "criss-cross" setup, that might cause write-out on some other DRBD,
         * which in turn might block on the other node at this very place.  */
-       peer_req = drbd_alloc_peer_req(peer_device, id, sector, data_size, trim == NULL, GFP_NOIO);
+       peer_req = drbd_alloc_peer_req(peer_device, id, sector, ds, data_size, GFP_NOIO);
        if (!peer_req)
                return NULL;
 
        peer_req->flags |= EE_WRITE;
-       if (trim)
+       if (trim) {
+               peer_req->flags |= EE_IS_TRIM;
                return peer_req;
+       }
+       if (wsame)
+               peer_req->flags |= EE_WRITE_SAME;
 
+       /* receive payload size bytes into page chain */
        ds = data_size;
        page = peer_req->pages;
        page_chain_for_each(page) {
@@ -1853,7 +1912,7 @@ read_in_block(struct drbd_peer_device *peer_device, u64 id, sector_t sector,
        }
 
        if (digest_size) {
-               drbd_csum_ee(peer_device->connection->peer_integrity_tfm, peer_req, dig_vv);
+               drbd_csum_ee_size(peer_device->connection->peer_integrity_tfm, peer_req, dig_vv, data_size);
                if (memcmp(dig_in, dig_vv, digest_size)) {
                        drbd_err(device, "Digest integrity check FAILED: %llus +%u\n",
                                (unsigned long long)sector, data_size);
@@ -2517,7 +2576,6 @@ static int receive_Data(struct drbd_connection *connection, struct packet_info *
        op = wire_flags_to_bio_op(dp_flags);
        op_flags = wire_flags_to_bio_flags(dp_flags);
        if (pi->cmd == P_TRIM) {
-               peer_req->flags |= EE_IS_TRIM;
                D_ASSERT(peer_device, peer_req->i.size > 0);
                D_ASSERT(peer_device, op == REQ_OP_DISCARD);
                D_ASSERT(peer_device, peer_req->pages == NULL);
@@ -2584,11 +2642,11 @@ static int receive_Data(struct drbd_connection *connection, struct packet_info *
                update_peer_seq(peer_device, peer_seq);
                spin_lock_irq(&device->resource->req_lock);
        }
-       /* if we use the zeroout fallback code, we process synchronously
-        * and we wait for all pending requests, respectively wait for
+       /* TRIM and WRITE_SAME are processed synchronously,
+        * we wait for all pending requests, respectively wait for
         * active_ee to become empty in drbd_submit_peer_request();
         * better not add ourselves here. */
-       if ((peer_req->flags & EE_IS_TRIM) == 0)
+       if ((peer_req->flags & (EE_IS_TRIM|EE_WRITE_SAME)) == 0)
                list_add_tail(&peer_req->w.list, &device->active_ee);
        spin_unlock_irq(&device->resource->req_lock);
 
@@ -2771,7 +2829,7 @@ static int receive_DataRequest(struct drbd_connection *connection, struct packet
         * "criss-cross" setup, that might cause write-out on some other DRBD,
         * which in turn might block on the other node at this very place.  */
        peer_req = drbd_alloc_peer_req(peer_device, p->block_id, sector, size,
-                       true /* has real payload */, GFP_NOIO);
+                       size, GFP_NOIO);
        if (!peer_req) {
                put_ldev(device);
                return -ENOMEM;
@@ -3933,6 +3991,7 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info
        struct drbd_peer_device *peer_device;
        struct drbd_device *device;
        struct p_sizes *p = pi->data;
+       struct o_qlim *o = (connection->agreed_features & DRBD_FF_WSAME) ? p->qlim : NULL;
        enum determine_dev_size dd = DS_UNCHANGED;
        sector_t p_size, p_usize, p_csize, my_usize;
        int ldsc = 0; /* local disk size changed */
@@ -4016,7 +4075,7 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info
 
        ddsf = be16_to_cpu(p->dds_flags);
        if (get_ldev(device)) {
-               drbd_reconsider_queue_parameters(device, device->ldev);
+               drbd_reconsider_queue_parameters(device, device->ldev, o);
                dd = drbd_determine_dev_size(device, ddsf, NULL);
                put_ldev(device);
                if (dd == DS_ERROR)
@@ -4036,7 +4095,7 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info
                 * However, if he sends a zero current size,
                 * take his (user-capped or) backing disk size anyways.
                 */
-               drbd_reconsider_queue_parameters(device, NULL);
+               drbd_reconsider_queue_parameters(device, NULL, o);
                drbd_set_my_capacity(device, p_csize ?: p_usize ?: p_size);
        }
 
@@ -4792,7 +4851,7 @@ static int receive_rs_deallocated(struct drbd_connection *connection, struct pac
                const int op = REQ_OP_DISCARD;
 
                peer_req = drbd_alloc_peer_req(peer_device, ID_SYNCER, sector,
-                                              size, false, GFP_NOIO);
+                                              size, 0, GFP_NOIO);
                if (!peer_req) {
                        put_ldev(device);
                        return -ENOMEM;
@@ -4837,7 +4896,7 @@ static int receive_rs_deallocated(struct drbd_connection *connection, struct pac
 
 struct data_cmd {
        int expect_payload;
-       size_t pkt_size;
+       unsigned int pkt_size;
        int (*fn)(struct drbd_connection *, struct packet_info *);
 };
 
@@ -4869,7 +4928,7 @@ static struct data_cmd drbd_cmd_handler[] = {
        [P_PROTOCOL_UPDATE] = { 1, sizeof(struct p_protocol), receive_protocol },
        [P_TRIM]            = { 0, sizeof(struct p_trim), receive_Data },
        [P_RS_DEALLOCATED]  = { 0, sizeof(struct p_block_desc), receive_rs_deallocated },
-
+       [P_WSAME]           = { 1, sizeof(struct p_wsame), receive_Data },
 };
 
 static void drbdd(struct drbd_connection *connection)
@@ -4879,7 +4938,7 @@ static void drbdd(struct drbd_connection *connection)
        int err;
 
        while (get_t_state(&connection->receiver) == RUNNING) {
-               struct data_cmd *cmd;
+               struct data_cmd const *cmd;
 
                drbd_thread_current_set_cpu(&connection->receiver);
                update_receiver_timing_details(connection, drbd_recv_header);
@@ -4894,11 +4953,18 @@ static void drbdd(struct drbd_connection *connection)
                }
 
                shs = cmd->pkt_size;
+               if (pi.cmd == P_SIZES && connection->agreed_features & DRBD_FF_WSAME)
+                       shs += sizeof(struct o_qlim);
                if (pi.size > shs && !cmd->expect_payload) {
                        drbd_err(connection, "No payload expected %s l:%d\n",
                                 cmdname(pi.cmd), pi.size);
                        goto err_out;
                }
+               if (pi.size < shs) {
+                       drbd_err(connection, "%s: unexpected packet size, expected:%d received:%d\n",
+                                cmdname(pi.cmd), (int)shs, pi.size);
+                       goto err_out;
+               }
 
                if (shs) {
                        update_receiver_timing_details(connection, drbd_recv_all_warn);
@@ -5145,11 +5211,12 @@ static int drbd_do_features(struct drbd_connection *connection)
        drbd_info(connection, "Handshake successful: "
             "Agreed network protocol version %d\n", connection->agreed_pro_version);
 
-       drbd_info(connection, "Agreed to%ssupport TRIM on protocol level\n",
-                 connection->agreed_features & FF_TRIM ? " " : " not ");
-
-       drbd_info(connection, "Agreed to%ssupport THIN_RESYNC on protocol level\n",
-                 connection->agreed_features & FF_THIN_RESYNC ? " " : " not ");
+       drbd_info(connection, "Feature flags enabled on protocol level: 0x%x%s%s%s.\n",
+                 connection->agreed_features,
+                 connection->agreed_features & DRBD_FF_TRIM ? " TRIM" : "",
+                 connection->agreed_features & DRBD_FF_THIN_RESYNC ? " THIN_RESYNC" : "",
+                 connection->agreed_features & DRBD_FF_WSAME ? " WRITE_SAME" :
+                 connection->agreed_features ? "" : " none");
 
        return 1;
 
index 6815127..a899487 100644 (file)
@@ -47,8 +47,7 @@ static void _drbd_end_io_acct(struct drbd_device *device, struct drbd_request *r
                            &device->vdisk->part0, req->start_jif);
 }
 
-static struct drbd_request *drbd_req_new(struct drbd_device *device,
-                                              struct bio *bio_src)
+static struct drbd_request *drbd_req_new(struct drbd_device *device, struct bio *bio_src)
 {
        struct drbd_request *req;
 
@@ -58,10 +57,12 @@ static struct drbd_request *drbd_req_new(struct drbd_device *device,
        memset(req, 0, sizeof(*req));
 
        drbd_req_make_private_bio(req, bio_src);
-       req->rq_state    = bio_data_dir(bio_src) == WRITE ? RQ_WRITE : 0;
-       req->device   = device;
-       req->master_bio  = bio_src;
-       req->epoch       = 0;
+       req->rq_state = (bio_data_dir(bio_src) == WRITE ? RQ_WRITE : 0)
+                     | (bio_op(bio_src) == REQ_OP_WRITE_SAME ? RQ_WSAME : 0)
+                     | (bio_op(bio_src) == REQ_OP_DISCARD ? RQ_UNMAP : 0);
+       req->device = device;
+       req->master_bio = bio_src;
+       req->epoch = 0;
 
        drbd_clear_interval(&req->i);
        req->i.sector     = bio_src->bi_iter.bi_sector;
index bb2ef78..eb49e7f 100644 (file)
@@ -206,6 +206,8 @@ enum drbd_req_state_bits {
 
        /* Set when this is a write, clear for a read */
        __RQ_WRITE,
+       __RQ_WSAME,
+       __RQ_UNMAP,
 
        /* Should call drbd_al_complete_io() for this request... */
        __RQ_IN_ACT_LOG,
@@ -241,10 +243,11 @@ enum drbd_req_state_bits {
 #define RQ_NET_OK          (1UL << __RQ_NET_OK)
 #define RQ_NET_SIS         (1UL << __RQ_NET_SIS)
 
-/* 0x1f8 */
 #define RQ_NET_MASK        (((1UL << __RQ_NET_MAX)-1) & ~RQ_LOCAL_MASK)
 
 #define RQ_WRITE           (1UL << __RQ_WRITE)
+#define RQ_WSAME           (1UL << __RQ_WSAME)
+#define RQ_UNMAP           (1UL << __RQ_UNMAP)
 #define RQ_IN_ACT_LOG      (1UL << __RQ_IN_ACT_LOG)
 #define RQ_POSTPONED      (1UL << __RQ_POSTPONED)
 #define RQ_COMPLETION_SUSP (1UL << __RQ_COMPLETION_SUSP)
index 8cc2ffb..364fed1 100644 (file)
@@ -320,6 +320,10 @@ void drbd_csum_bio(struct crypto_ahash *tfm, struct bio *bio, void *digest)
                sg_set_page(&sg, bvec.bv_page, bvec.bv_len, bvec.bv_offset);
                ahash_request_set_crypt(req, &sg, NULL, sg.length);
                crypto_ahash_update(req);
+               /* REQ_OP_WRITE_SAME has only one segment,
+                * checksum the payload only once. */
+               if (bio_op(bio) == REQ_OP_WRITE_SAME)
+                       break;
        }
        ahash_request_set_crypt(req, NULL, digest, 0);
        crypto_ahash_final(req);
@@ -387,7 +391,7 @@ static int read_for_csum(struct drbd_peer_device *peer_device, sector_t sector,
        /* GFP_TRY, because if there is no memory available right now, this may
         * be rescheduled for later. It is "only" background resync, after all. */
        peer_req = drbd_alloc_peer_req(peer_device, ID_SYNCER /* unused */, sector,
-                                      size, true /* has real payload */, GFP_TRY);
+                                      size, size, GFP_TRY);
        if (!peer_req)
                goto defer;
 
@@ -603,7 +607,7 @@ static int make_resync_request(struct drbd_device *const device, int cancel)
                return 0;
        }
 
-       if (connection->agreed_features & FF_THIN_RESYNC) {
+       if (connection->agreed_features & DRBD_FF_THIN_RESYNC) {
                rcu_read_lock();
                discard_granularity = rcu_dereference(device->ldev->disk_conf)->rs_discard_granularity;
                rcu_read_unlock();