nbd patches for 2019-04-08

- Fix minor issues in recent alignment patches
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Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2019-04-08' into staging

nbd patches for 2019-04-08

- Fix minor issues in recent alignment patches

# gpg: Signature made Mon 08 Apr 2019 19:53:48 BST
# gpg:                using RSA key A7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>" [full]
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>" [full]
# gpg:                 aka "[jpeg image of size 6874]" [full]
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-nbd-2019-04-08:
  nbd/client: Fix error message for server with unusable sizing
  nbd/server: Don't fail NBD_OPT_INFO for byte-aligned sources
  nbd/server: Trace client noncompliance on unaligned requests
  nbd/server: Fix blockstatus trace

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

nbd/client.c

@@ -428,7 +428,7 @@ static int nbd_opt_info_or_go(QIOChannel *ioc, uint32_t opt,
             }
             if (info->min_block &&
                 !QEMU_IS_ALIGNED(info->size, info->min_block)) {
-                error_setg(errp, "export size %" PRIu64 "is not multiple of "
+                error_setg(errp, "export size %" PRIu64 " is not multiple of "
                            "minimum block size %" PRIu32, info->size,
                            info->min_block);
                 nbd_send_opt_abort(ioc);

nbd/server.c

@@ -124,6 +124,8 @@ struct NBDClient {
     int nb_requests;
     bool closing;
 
+    uint32_t check_align; /* If non-zero, check for aligned client requests */
+
     bool structured_reply;
     NBDExportMetaContexts export_meta;
 
@@ -533,6 +535,7 @@ static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags,
     bool blocksize = false;
     uint32_t sizes[3];
     char buf[sizeof(uint64_t) + sizeof(uint16_t)];
+    uint32_t check_align = 0;
 
     /* Client sends:
         4 bytes: L, name length (can be 0)
@@ -609,7 +612,7 @@ static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags,
      * whether this is OPT_INFO or OPT_GO. */
     /* minimum - 1 for back-compat, or actual if client will obey it. */
     if (client->opt == NBD_OPT_INFO || blocksize) {
-        sizes[0] = blk_get_request_alignment(exp->blk);
+        check_align = sizes[0] = blk_get_request_alignment(exp->blk);
     } else {
         sizes[0] = 1;
     }
@@ -640,11 +643,14 @@ static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags,
         return rc;
     }
 
-    /* If the client is just asking for NBD_OPT_INFO, but forgot to
+    /*
-     * request block sizes, return an error.
+     * If the client is just asking for NBD_OPT_INFO, but forgot to
-     * TODO: consult blk_bs(blk)->request_align, and only error if it
+     * request block sizes in a situation that would impact
-     * is not 1? */
+     * performance, then return an error. But for NBD_OPT_GO, we
-    if (client->opt == NBD_OPT_INFO && !blocksize) {
+     * tolerate all clients, regardless of alignments.
+     */
+    if (client->opt == NBD_OPT_INFO && !blocksize &&
+        blk_get_request_alignment(exp->blk) > 1) {
         return nbd_negotiate_send_rep_err(client,
                                           NBD_REP_ERR_BLOCK_SIZE_REQD,
                                           errp,
@@ -660,6 +666,7 @@ static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags,
 
     if (client->opt == NBD_OPT_GO) {
         client->exp = exp;
+        client->check_align = check_align;
         QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
         nbd_export_get(client->exp);
         nbd_check_meta_export(client);
@@ -1880,17 +1887,12 @@ static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset,
 
         flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) |
                 (ret & BDRV_BLOCK_ZERO      ? NBD_STATE_ZERO : 0);
-        offset += num;
-        remaining_bytes -= num;
 
         if (first_extent) {
             extent->flags = flags;
             extent->length = num;
             first_extent = false;
-            continue;
+        } else if (flags == extent->flags) {
-        }
-
-        if (flags == extent->flags) {
             /* extend current extent */
             extent->length += num;
         } else {
@@ -1903,6 +1905,8 @@ static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset,
             extent->flags = flags;
             extent->length = num;
         }
+        offset += num;
+        remaining_bytes -= num;
     }
 
     extents_end = extent + 1;
@@ -2129,6 +2133,17 @@ static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request,
         return (request->type == NBD_CMD_WRITE ||
                 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL;
     }
+    if (client->check_align && !QEMU_IS_ALIGNED(request->from | request->len,
+                                                client->check_align)) {
+        /*
+         * The block layer gracefully handles unaligned requests, but
+         * it's still worth tracing client non-compliance
+         */
+        trace_nbd_co_receive_align_compliance(nbd_cmd_lookup(request->type),
+                                              request->from,
+                                              request->len,
+                                              client->check_align);
+    }
     valid_flags = NBD_CMD_FLAG_FUA;
     if (request->type == NBD_CMD_READ && client->structured_reply) {
         valid_flags |= NBD_CMD_FLAG_DF;

nbd/trace-events

@@ -71,4 +71,5 @@ nbd_co_send_extents(uint64_t handle, unsigned int extents, uint32_t id, uint64_t
 nbd_co_send_structured_error(uint64_t handle, int err, const char *errname, const char *msg) "Send structured error reply: handle = %" PRIu64 ", error = %d (%s), msg = '%s'"
 nbd_co_receive_request_decode_type(uint64_t handle, uint16_t type, const char *name) "Decoding type: handle = %" PRIu64 ", type = %" PRIu16 " (%s)"
 nbd_co_receive_request_payload_received(uint64_t handle, uint32_t len) "Payload received: handle = %" PRIu64 ", len = %" PRIu32
+nbd_co_receive_align_compliance(const char *op, uint64_t from, uint32_t len, uint32_t align) "client sent non-compliant unaligned %s request: from=0x%" PRIx64 ", len=0x%" PRIx32 ", align=0x%" PRIx32
 nbd_trip(void) "Reading request"