[Qemu-devel] [PULL 0/8] NBD patches for 2019-02-04

[Qemu-devel] [PULL 0/8] NBD patches for 2019-02-04

[Eric Blake]

The following changes since commit 773c4a6228fd910556cee2d477ee56c591a30000:

  test-filter-mirror: pass UNIX domain socket through fd (2019-02-04 16:03:20 +0000)

are available in the Git repository at:

  https://repo.or.cz/qemu/ericb.git tags/pull-nbd-2019-02-04

for you to fetch changes up to bc5a03350c220698229e7d6929dd242d5d358345:

  block/nbd-client: rename read_reply_co to connection_co (2019-02-04 15:11:27 -0600)

----------------------------------------------------------------
nbd patches for 2019-02-04

- deprecate 'qemu-nbd --partition'
- preparation for NBD reconnect, including better logging of read errors

----------------------------------------------------------------
Eric Blake (1):
      qemu-nbd: Deprecate qemu-nbd --partition

Vladimir Sementsov-Ogievskiy (7):
      nbd: generalize usage of nbd_read
      block/nbd-client: split channel errors from export errors
      block/nbd: move connection code from block/nbd to block/nbd-client
      block/nbd-client: split connection from initialization
      block/nbd-client: fix nbd_reply_chunk_iter_receive
      block/nbd-client: don't check ioc
      block/nbd-client: rename read_reply_co to connection_co

 qemu-deprecated.texi |  33 +++++++++
 qemu-nbd.texi        |   6 +-
 block/nbd-client.h   |   6 +-
 include/block/nbd.h  |  32 ++++++++-
 block/nbd-client.c   | 199 ++++++++++++++++++++++++++++++++-------------------
 block/nbd.c          |  40 +----------
 nbd/client.c         |  88 ++++++++---------------
 nbd/common.c         |   2 +-
 nbd/server.c         |  27 +++----
 qemu-nbd.c           |   2 +
 10 files changed, 239 insertions(+), 196 deletions(-)

-- 
2.20.1

[Qemu-devel] [PULL 1/8] qemu-nbd: Deprecate qemu-nbd --partition

[Eric Blake]

The existing qemu-nbd --partition code claims to handle logical
partitions up to 8, since its introduction in 2008 (commit 7a5ca86).
However, the implementation is bogus (actual MBR logical partitions
form a sort of linked list, with one partition per extended table
entry, rather than four logical partitions in a single extended
table), making the code unlikely to work for anything beyond -P5 on
actual guest images. What's more, the code does not support GPT
partitions, which are becoming more popular, and maintaining device
subsetting in both NBD and the raw device is unnecessary duplication
of effort (even if it is not too difficult).

Note that obtaining the offsets of a partition (MBR or GPT) can be
learned by using 'qemu-nbd -c /dev/nbd0 file.qcow2 && sfdisk --dump
/dev/nbd0', but by the time you've done that, you might as well
just mount /dev/nbd0p1 that the kernel creates for you instead of
bothering with qemu exporting a subset.  Or, keeping to just
user-space code, use nbdkit's partition filter, which has already
known both GPT and primary MBR partitions for a while, and was
just recently enhanced to support arbitrary logical MBR parititions.

Start the clock on the deprecation cycle, with examples of how
to accomplish device subsetting without using -P.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190125234837.2272-1-eblake@redhat.com>
Reviewed-by: Richard W.M. Jones <rjones@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
---
 qemu-deprecated.texi | 33 +++++++++++++++++++++++++++++++++
 qemu-nbd.texi        |  6 ++++--
 qemu-nbd.c           |  2 ++
 3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi
index 9cc20b365c5..8a6174df0c1 100644
--- a/qemu-deprecated.texi
+++ b/qemu-deprecated.texi
@@ -160,3 +160,36 @@ Example of legacy encoding:
 The above, converted to the current supported format:

 @code{json:@{"file.driver":"rbd", "file.pool":"rbd", "file.image":"name"@}}
+
+@section Related binaries
+
+@subsection qemu-nbd --partition (since 4.0.0)
+
+The ``qemu-nbd --partition $digit'' code (also spelled @option{-P})
+can only handle MBR partitions, and has never correctly handled
+logical partitions beyond partition 5.  If you know the offset and
+length of the partition (perhaps by using @code{sfdisk} within the
+guest), you can achieve the effect of exporting just that subset of
+the disk by use of the @option{--image-opts} option with a raw
+blockdev using the @code{offset} and @code{size} parameters layered on
+top of any other existing blockdev. For example, if partition 1 is
+100MiB long starting at 1MiB, the old command:
+
+@code{qemu-nbd -t -P 1 -f qcow2 file.qcow2}
+
+can be rewritten as:
+
+@code{qemu-nbd -t --image-opts driver=raw,offset=1M,size=100M,file.driver=qcow2,file.backing.driver=file,file.backing.filename=file.qcow2}
+
+Alternatively, the @code{nbdkit} project provides a more powerful
+partition filter on top of its nbd plugin, which can be used to select
+an arbitrary MBR or GPT partition on top of any other full-image NBD
+export.  Using this to rewrite the above example results in:
+
+@code{qemu-nbd -t -k /tmp/sock -f qcow2 file.qcow2 &}
+@code{nbdkit -f --filter=partition nbd socket=/tmp/sock partition=1}
+
+Note that if you are exposing the export via /dev/nbd0, it is easier
+to just export the entire image and then mount only /dev/nbd0p1 than
+it is to reinvoke @command{qemu-nbd -c /dev/nbd0} limited to just a
+subset of the image.
diff --git a/qemu-nbd.texi b/qemu-nbd.texi
index 386bece4680..d0c51828149 100644
--- a/qemu-nbd.texi
+++ b/qemu-nbd.texi
@@ -56,8 +56,10 @@ auto-detecting.
 @item -r, --read-only
 Export the disk as read-only.
 @item -P, --partition=@var{num}
-Only expose MBR partition @var{num}.  Understands physical partitions
-1-4 and logical partitions 5-8.
+Deprecated: Only expose MBR partition @var{num}.  Understands physical
+partitions 1-4 and logical partition 5. New code should instead use
+@option{--image-opts} with the raw driver wrapping a subset of the
+original image.
 @item -B, --bitmap=@var{name}
 If @var{filename} has a qcow2 persistent bitmap @var{name}, expose
 that bitmap via the ``qemu:dirty-bitmap:@var{name}'' context
diff --git a/qemu-nbd.c b/qemu-nbd.c
index 1f7b2a03f5d..00c07fd27ea 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -787,6 +787,8 @@ int main(int argc, char **argv)
             flags &= ~BDRV_O_RDWR;
             break;
         case 'P':
+            warn_report("The '-P' option is deprecated; use --image-opts with "
+                        "a raw device wrapper for subset exports instead");
             if (qemu_strtoi(optarg, NULL, 0, &partition) < 0 ||
                 partition < 1 || partition > 8) {
                 error_report("Invalid partition '%s'", optarg);
-- 
2.20.1

[Qemu-devel] [PULL 2/8] nbd: generalize usage of nbd_read

[Eric Blake]

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

We generally do very similar things around nbd_read: error_prepend
specifying what we have tried to read, and be_to_cpu conversion of
integers.

So, it seems reasonable to move common things to helper functions,
which:
1. simplify code a bit
2. generalize nbd_read error descriptions, all starting with
   "Failed to read"
3. make it more difficult to forget to convert things from BE

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190128165830.165170-1-vsementsov@virtuozzo.com>
[eblake: rename macro to DEF_NBD_READ_N and formatting tweaks;
checkpatch has false positive complaint]
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 include/block/nbd.h | 32 +++++++++++++++--
 block/nbd-client.c  |  5 ++-
 nbd/client.c        | 88 +++++++++++++++------------------------------
 nbd/common.c        |  2 +-
 nbd/server.c        | 27 +++++---------
 5 files changed, 71 insertions(+), 83 deletions(-)

diff --git a/include/block/nbd.h b/include/block/nbd.h
index 4faf394e346..96cfb1d7d5d 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -23,6 +23,7 @@
 #include "qapi/qapi-types-block.h"
 #include "io/channel-socket.h"
 #include "crypto/tlscreds.h"
+#include "qapi/error.h"

 /* Handshake phase structs - this struct is passed on the wire */

@@ -336,11 +337,38 @@ void nbd_server_start(SocketAddress *addr, const char *tls_creds,
  * Reads @size bytes from @ioc. Returns 0 on success.
  */
 static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size,
-                           Error **errp)
+                           const char *desc, Error **errp)
 {
-    return qio_channel_read_all(ioc, buffer, size, errp) < 0 ? -EIO : 0;
+    int ret = qio_channel_read_all(ioc, buffer, size, errp) < 0 ? -EIO : 0;
+
+    if (ret < 0) {
+        if (desc) {
+            error_prepend(errp, "Failed to read %s: ", desc);
+        }
+        return -1;
+    }
+
+    return 0;
 }

+#define DEF_NBD_READ_N(bits)                                            \
+static inline int nbd_read##bits(QIOChannel *ioc,                       \
+                                 uint##bits##_t *val,                   \
+                                 const char *desc, Error **errp)        \
+{                                                                       \
+    if (nbd_read(ioc, val, sizeof(*val), desc, errp) < 0) {             \
+        return -1;                                                      \
+    }                                                                   \
+    *val = be##bits##_to_cpu(*val);                                     \
+    return 0;                                                           \
+}
+
+DEF_NBD_READ_N(16) /* Defines nbd_read16(). */
+DEF_NBD_READ_N(32) /* Defines nbd_read32(). */
+DEF_NBD_READ_N(64) /* Defines nbd_read64(). */
+
+#undef DEF_NBD_READ_N
+
 static inline bool nbd_reply_is_simple(NBDReply *reply)
 {
     return reply->magic == NBD_SIMPLE_REPLY_MAGIC;
diff --git a/block/nbd-client.c b/block/nbd-client.c
index 50a8dadd852..57f679ad4d0 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -338,10 +338,9 @@ static int nbd_co_receive_offset_data_payload(NBDClientSession *s,
         return -EINVAL;
     }

-    if (nbd_read(s->ioc, &offset, sizeof(offset), errp) < 0) {
+    if (nbd_read64(s->ioc, &offset, "OFFSET_DATA offset", errp) < 0) {
         return -EIO;
     }
-    be64_to_cpus(&offset);

     data_size = chunk->length - sizeof(offset);
     assert(data_size);
@@ -388,7 +387,7 @@ static coroutine_fn int nbd_co_receive_structured_payload(
     }

     *payload = g_new(char, len);
-    ret = nbd_read(s->ioc, *payload, len, errp);
+    ret = nbd_read(s->ioc, *payload, len, "structured payload", errp);
     if (ret < 0) {
         g_free(*payload);
         *payload = NULL;
diff --git a/nbd/client.c b/nbd/client.c
index 8a083c2f42c..10a52ad7d0c 100644
--- a/nbd/client.c
+++ b/nbd/client.c
@@ -113,8 +113,7 @@ static int nbd_receive_option_reply(QIOChannel *ioc, uint32_t opt,
                                     NBDOptionReply *reply, Error **errp)
 {
     QEMU_BUILD_BUG_ON(sizeof(*reply) != 20);
-    if (nbd_read(ioc, reply, sizeof(*reply), errp) < 0) {
-        error_prepend(errp, "failed to read option reply: ");
+    if (nbd_read(ioc, reply, sizeof(*reply), "option reply", errp) < 0) {
         nbd_send_opt_abort(ioc);
         return -1;
     }
@@ -166,8 +165,8 @@ static int nbd_handle_reply_err(QIOChannel *ioc, NBDOptionReply *reply,
             goto cleanup;
         }
         msg = g_malloc(reply->length + 1);
-        if (nbd_read(ioc, msg, reply->length, errp) < 0) {
-            error_prepend(errp, "failed to read option error %" PRIu32
+        if (nbd_read(ioc, msg, reply->length, NULL, errp) < 0) {
+            error_prepend(errp, "Failed to read option error %" PRIu32
                           " (%s) message: ",
                           reply->type, nbd_rep_lookup(reply->type));
             goto cleanup;
@@ -284,12 +283,10 @@ static int nbd_receive_list(QIOChannel *ioc, char **name, char **description,
         nbd_send_opt_abort(ioc);
         return -1;
     }
-    if (nbd_read(ioc, &namelen, sizeof(namelen), errp) < 0) {
-        error_prepend(errp, "failed to read option name length: ");
+    if (nbd_read32(ioc, &namelen, "option name length", errp) < 0) {
         nbd_send_opt_abort(ioc);
         return -1;
     }
-    namelen = be32_to_cpu(namelen);
     len -= sizeof(namelen);
     if (len < namelen) {
         error_setg(errp, "incorrect option name length");
@@ -298,8 +295,7 @@ static int nbd_receive_list(QIOChannel *ioc, char **name, char **description,
     }

     local_name = g_malloc(namelen + 1);
-    if (nbd_read(ioc, local_name, namelen, errp) < 0) {
-        error_prepend(errp, "failed to read export name: ");
+    if (nbd_read(ioc, local_name, namelen, "export name", errp) < 0) {
         nbd_send_opt_abort(ioc);
         goto out;
     }
@@ -307,8 +303,7 @@ static int nbd_receive_list(QIOChannel *ioc, char **name, char **description,
     len -= namelen;
     if (len) {
         local_desc = g_malloc(len + 1);
-        if (nbd_read(ioc, local_desc, len, errp) < 0) {
-            error_prepend(errp, "failed to read export description: ");
+        if (nbd_read(ioc, local_desc, len, "export description", errp) < 0) {
             nbd_send_opt_abort(ioc);
             goto out;
         }
@@ -410,13 +405,11 @@ static int nbd_opt_info_or_go(QIOChannel *ioc, uint32_t opt,
             nbd_send_opt_abort(ioc);
             return -1;
         }
-        if (nbd_read(ioc, &type, sizeof(type), errp) < 0) {
-            error_prepend(errp, "failed to read info type: ");
+        if (nbd_read16(ioc, &type, "info type", errp) < 0) {
             nbd_send_opt_abort(ioc);
             return -1;
         }
         len -= sizeof(type);
-        type = be16_to_cpu(type);
         switch (type) {
         case NBD_INFO_EXPORT:
             if (len != sizeof(info->size) + sizeof(info->flags)) {
@@ -425,18 +418,14 @@ static int nbd_opt_info_or_go(QIOChannel *ioc, uint32_t opt,
                 nbd_send_opt_abort(ioc);
                 return -1;
             }
-            if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) {
-                error_prepend(errp, "failed to read info size: ");
+            if (nbd_read64(ioc, &info->size, "info size", errp) < 0) {
                 nbd_send_opt_abort(ioc);
                 return -1;
             }
-            info->size = be64_to_cpu(info->size);
-            if (nbd_read(ioc, &info->flags, sizeof(info->flags), errp) < 0) {
-                error_prepend(errp, "failed to read info flags: ");
+            if (nbd_read16(ioc, &info->flags, "info flags", errp) < 0) {
                 nbd_send_opt_abort(ioc);
                 return -1;
             }
-            info->flags = be16_to_cpu(info->flags);
             trace_nbd_receive_negotiate_size_flags(info->size, info->flags);
             break;

@@ -447,27 +436,23 @@ static int nbd_opt_info_or_go(QIOChannel *ioc, uint32_t opt,
                 nbd_send_opt_abort(ioc);
                 return -1;
             }
-            if (nbd_read(ioc, &info->min_block, sizeof(info->min_block),
-                         errp) < 0) {
-                error_prepend(errp, "failed to read info minimum block size: ");
+            if (nbd_read32(ioc, &info->min_block, "info minimum block size",
+                           errp) < 0) {
                 nbd_send_opt_abort(ioc);
                 return -1;
             }
-            info->min_block = be32_to_cpu(info->min_block);
             if (!is_power_of_2(info->min_block)) {
                 error_setg(errp, "server minimum block size %" PRIu32
                            " is not a power of two", info->min_block);
                 nbd_send_opt_abort(ioc);
                 return -1;
             }
-            if (nbd_read(ioc, &info->opt_block, sizeof(info->opt_block),
-                         errp) < 0) {
-                error_prepend(errp,
-                              "failed to read info preferred block size: ");
+            if (nbd_read32(ioc, &info->opt_block, "info preferred block size",
+                           errp) < 0)
+            {
                 nbd_send_opt_abort(ioc);
                 return -1;
             }
-            info->opt_block = be32_to_cpu(info->opt_block);
             if (!is_power_of_2(info->opt_block) ||
                 info->opt_block < info->min_block) {
                 error_setg(errp, "server preferred block size %" PRIu32
@@ -475,13 +460,12 @@ static int nbd_opt_info_or_go(QIOChannel *ioc, uint32_t opt,
                 nbd_send_opt_abort(ioc);
                 return -1;
             }
-            if (nbd_read(ioc, &info->max_block, sizeof(info->max_block),
-                         errp) < 0) {
-                error_prepend(errp, "failed to read info maximum block size: ");
+            if (nbd_read32(ioc, &info->max_block, "info maximum block size",
+                           errp) < 0)
+            {
                 nbd_send_opt_abort(ioc);
                 return -1;
             }
-            info->max_block = be32_to_cpu(info->max_block);
             if (info->max_block < info->min_block) {
                 error_setg(errp, "server maximum block size %" PRIu32
                            " is not valid", info->max_block);
@@ -731,14 +715,13 @@ static int nbd_receive_one_meta_context(QIOChannel *ioc,
         return -1;
     }

-    if (nbd_read(ioc, &local_id, sizeof(local_id), errp) < 0) {
+    if (nbd_read32(ioc, &local_id, "context id", errp) < 0) {
         return -1;
     }
-    local_id = be32_to_cpu(local_id);

     reply.length -= sizeof(local_id);
     local_name = g_malloc(reply.length + 1);
-    if (nbd_read(ioc, local_name, reply.length, errp) < 0) {
+    if (nbd_read(ioc, local_name, reply.length, "context name", errp) < 0) {
         g_free(local_name);
         return -1;
     }
@@ -896,11 +879,9 @@ static int nbd_start_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
         return -EINVAL;
     }

-    if (nbd_read(ioc, &magic, sizeof(magic), errp) < 0) {
-        error_prepend(errp, "Failed to read initial magic: ");
+    if (nbd_read64(ioc, &magic, "initial magic", errp) < 0) {
         return -EINVAL;
     }
-    magic = be64_to_cpu(magic);
     trace_nbd_receive_negotiate_magic(magic);

     if (magic != NBD_INIT_MAGIC) {
@@ -908,11 +889,9 @@ static int nbd_start_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
         return -EINVAL;
     }

-    if (nbd_read(ioc, &magic, sizeof(magic), errp) < 0) {
-        error_prepend(errp, "Failed to read server magic: ");
+    if (nbd_read64(ioc, &magic, "server magic", errp) < 0) {
         return -EINVAL;
     }
-    magic = be64_to_cpu(magic);
     trace_nbd_receive_negotiate_magic(magic);

     if (magic == NBD_OPTS_MAGIC) {
@@ -920,11 +899,9 @@ static int nbd_start_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
         uint16_t globalflags;
         bool fixedNewStyle = false;

-        if (nbd_read(ioc, &globalflags, sizeof(globalflags), errp) < 0) {
-            error_prepend(errp, "Failed to read server flags: ");
+        if (nbd_read16(ioc, &globalflags, "server flags", errp) < 0) {
             return -EINVAL;
         }
-        globalflags = be16_to_cpu(globalflags);
         trace_nbd_receive_negotiate_server_flags(globalflags);
         if (globalflags & NBD_FLAG_FIXED_NEWSTYLE) {
             fixedNewStyle = true;
@@ -992,17 +969,13 @@ static int nbd_negotiate_finish_oldstyle(QIOChannel *ioc, NBDExportInfo *info,
 {
     uint32_t oldflags;

-    if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) {
-        error_prepend(errp, "Failed to read export length: ");
+    if (nbd_read64(ioc, &info->size, "export length", errp) < 0) {
         return -EINVAL;
     }
-    info->size = be64_to_cpu(info->size);

-    if (nbd_read(ioc, &oldflags, sizeof(oldflags), errp) < 0) {
-        error_prepend(errp, "Failed to read export flags: ");
+    if (nbd_read32(ioc, &oldflags, "export flags", errp) < 0) {
         return -EINVAL;
     }
-    oldflags = be32_to_cpu(oldflags);
     if (oldflags & ~0xffff) {
         error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags);
         return -EINVAL;
@@ -1079,17 +1052,13 @@ int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
         }

         /* Read the response */
-        if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) {
-            error_prepend(errp, "Failed to read export length: ");
+        if (nbd_read64(ioc, &info->size, "export length", errp) < 0) {
             return -EINVAL;
         }
-        info->size = be64_to_cpu(info->size);

-        if (nbd_read(ioc, &info->flags, sizeof(info->flags), errp) < 0) {
-            error_prepend(errp, "Failed to read export flags: ");
+        if (nbd_read16(ioc, &info->flags, "export flags", errp) < 0) {
             return -EINVAL;
         }
-        info->flags = be16_to_cpu(info->flags);
         break;
     case 0: /* oldstyle, parse length and flags */
         if (*info->name) {
@@ -1379,7 +1348,7 @@ static int nbd_receive_simple_reply(QIOChannel *ioc, NBDSimpleReply *reply,
     assert(reply->magic == NBD_SIMPLE_REPLY_MAGIC);

     ret = nbd_read(ioc, (uint8_t *)reply + sizeof(reply->magic),
-                   sizeof(*reply) - sizeof(reply->magic), errp);
+                   sizeof(*reply) - sizeof(reply->magic), "reply", errp);
     if (ret < 0) {
         return ret;
     }
@@ -1404,7 +1373,8 @@ static int nbd_receive_structured_reply_chunk(QIOChannel *ioc,
     assert(chunk->magic == NBD_STRUCTURED_REPLY_MAGIC);

     ret = nbd_read(ioc, (uint8_t *)chunk + sizeof(chunk->magic),
-                   sizeof(*chunk) - sizeof(chunk->magic), errp);
+                   sizeof(*chunk) - sizeof(chunk->magic), "structured chunk",
+                   errp);
     if (ret < 0) {
         return ret;
     }
diff --git a/nbd/common.c b/nbd/common.c
index 41f5ed8d9fa..cc8b278e541 100644
--- a/nbd/common.c
+++ b/nbd/common.c
@@ -31,7 +31,7 @@ int nbd_drop(QIOChannel *ioc, size_t size, Error **errp)
     buffer = sizeof(small) >= size ? small : g_malloc(MIN(65536, size));
     while (size > 0) {
         ssize_t count = MIN(65536, size);
-        ret = nbd_read(ioc, buffer, MIN(65536, size), errp);
+        ret = nbd_read(ioc, buffer, MIN(65536, size), NULL, errp);

         if (ret < 0) {
             goto cleanup;
diff --git a/nbd/server.c b/nbd/server.c
index cb0d5634fa1..838c150d8ca 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -438,8 +438,7 @@ static int nbd_negotiate_handle_export_name(NBDClient *client,
         error_setg(errp, "Bad length received");
         return -EINVAL;
     }
-    if (nbd_read(client->ioc, name, client->optlen, errp) < 0) {
-        error_prepend(errp, "read failed: ");
+    if (nbd_read(client->ioc, name, client->optlen, "export name", errp) < 0) {
         return -EIO;
     }
     name[client->optlen] = '\0';
@@ -1046,11 +1045,9 @@ static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,
         ...           Rest of request
     */

-    if (nbd_read(client->ioc, &flags, sizeof(flags), errp) < 0) {
-        error_prepend(errp, "read failed: ");
+    if (nbd_read32(client->ioc, &flags, "flags", errp) < 0) {
         return -EIO;
     }
-    flags = be32_to_cpu(flags);
     trace_nbd_negotiate_options_flags(flags);
     if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {
         fixedNewstyle = true;
@@ -1070,30 +1067,23 @@ static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,
         uint32_t option, length;
         uint64_t magic;

-        if (nbd_read(client->ioc, &magic, sizeof(magic), errp) < 0) {
-            error_prepend(errp, "read failed: ");
+        if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) {
             return -EINVAL;
         }
-        magic = be64_to_cpu(magic);
         trace_nbd_negotiate_options_check_magic(magic);
         if (magic != NBD_OPTS_MAGIC) {
             error_setg(errp, "Bad magic received");
             return -EINVAL;
         }

-        if (nbd_read(client->ioc, &option,
-                     sizeof(option), errp) < 0) {
-            error_prepend(errp, "read failed: ");
+        if (nbd_read32(client->ioc, &option, "option", errp) < 0) {
             return -EINVAL;
         }
-        option = be32_to_cpu(option);
         client->opt = option;

-        if (nbd_read(client->ioc, &length, sizeof(length), errp) < 0) {
-            error_prepend(errp, "read failed: ");
+        if (nbd_read32(client->ioc, &length, "option length", errp) < 0) {
             return -EINVAL;
         }
-        length = be32_to_cpu(length);
         assert(!client->optlen);
         client->optlen = length;

@@ -1306,7 +1296,7 @@ static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request,
     uint32_t magic;
     int ret;

-    ret = nbd_read(ioc, buf, sizeof(buf), errp);
+    ret = nbd_read(ioc, buf, sizeof(buf), "request", errp);
     if (ret < 0) {
         return ret;
     }
@@ -2111,8 +2101,9 @@ static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request,
         }
     }
     if (request->type == NBD_CMD_WRITE) {
-        if (nbd_read(client->ioc, req->data, request->len, errp) < 0) {
-            error_prepend(errp, "reading from socket failed: ");
+        if (nbd_read(client->ioc, req->data, request->len, "CMD_WRITE data",
+                     errp) < 0)
+        {
             return -EIO;
         }
         req->complete = true;
-- 
2.20.1

[Qemu-devel] [PULL 3/8] block/nbd-client: split channel errors from export errors

[Eric Blake]

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

To implement nbd reconnect in further patches, we need to distinguish
error codes, returned by nbd server, from channel errors, to reconnect
only in the latter case.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190201130138.94525-2-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 block/nbd-client.c | 83 ++++++++++++++++++++++++++--------------------
 1 file changed, 47 insertions(+), 36 deletions(-)

diff --git a/block/nbd-client.c b/block/nbd-client.c
index 57f679ad4d0..fd58cda2f17 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -504,11 +504,11 @@ static coroutine_fn int nbd_co_do_receive_one_chunk(
  */
 static coroutine_fn int nbd_co_receive_one_chunk(
         NBDClientSession *s, uint64_t handle, bool only_structured,
-        QEMUIOVector *qiov, NBDReply *reply, void **payload, Error **errp)
+        int *request_ret, QEMUIOVector *qiov, NBDReply *reply, void **payload,
+        Error **errp)
 {
-    int request_ret;
     int ret = nbd_co_do_receive_one_chunk(s, handle, only_structured,
-                                          &request_ret, qiov, payload, errp);
+                                          request_ret, qiov, payload, errp);

     if (ret < 0) {
         s->quit = true;
@@ -518,7 +518,6 @@ static coroutine_fn int nbd_co_receive_one_chunk(
             *reply = s->reply;
         }
         s->reply.handle = 0;
-        ret = request_ret;
     }

     if (s->read_reply_co) {
@@ -530,22 +529,17 @@ static coroutine_fn int nbd_co_receive_one_chunk(

 typedef struct NBDReplyChunkIter {
     int ret;
-    bool fatal;
+    int request_ret;
     Error *err;
     bool done, only_structured;
 } NBDReplyChunkIter;

-static void nbd_iter_error(NBDReplyChunkIter *iter, bool fatal,
-                           int ret, Error **local_err)
+static void nbd_iter_channel_error(NBDReplyChunkIter *iter,
+                                   int ret, Error **local_err)
 {
     assert(ret < 0);

-    if ((fatal && !iter->fatal) || iter->ret == 0) {
-        if (iter->ret != 0) {
-            error_free(iter->err);
-            iter->err = NULL;
-        }
-        iter->fatal = fatal;
+    if (!iter->ret) {
         iter->ret = ret;
         error_propagate(&iter->err, *local_err);
     } else {
@@ -555,6 +549,15 @@ static void nbd_iter_error(NBDReplyChunkIter *iter, bool fatal,
     *local_err = NULL;
 }

+static void nbd_iter_request_error(NBDReplyChunkIter *iter, int ret)
+{
+    assert(ret < 0);
+
+    if (!iter->request_ret) {
+        iter->request_ret = ret;
+    }
+}
+
 /* NBD_FOREACH_REPLY_CHUNK
  */
 #define NBD_FOREACH_REPLY_CHUNK(s, iter, handle, structured, \
@@ -570,13 +573,13 @@ static bool nbd_reply_chunk_iter_receive(NBDClientSession *s,
                                          QEMUIOVector *qiov, NBDReply *reply,
                                          void **payload)
 {
-    int ret;
+    int ret, request_ret;
     NBDReply local_reply;
     NBDStructuredReplyChunk *chunk;
     Error *local_err = NULL;
     if (s->quit) {
         error_setg(&local_err, "Connection closed");
-        nbd_iter_error(iter, true, -EIO, &local_err);
+        nbd_iter_channel_error(iter, -EIO, &local_err);
         goto break_loop;
     }

@@ -590,10 +593,12 @@ static bool nbd_reply_chunk_iter_receive(NBDClientSession *s,
     }

     ret = nbd_co_receive_one_chunk(s, handle, iter->only_structured,
-                                   qiov, reply, payload, &local_err);
+                                   &request_ret, qiov, reply, payload,
+                                   &local_err);
     if (ret < 0) {
-        /* If it is a fatal error s->quit is set by nbd_co_receive_one_chunk */
-        nbd_iter_error(iter, s->quit, ret, &local_err);
+        nbd_iter_channel_error(iter, ret, &local_err);
+    } else if (request_ret < 0) {
+        nbd_iter_request_error(iter, request_ret);
     }

     /* Do not execute the body of NBD_FOREACH_REPLY_CHUNK for simple reply. */
@@ -630,7 +635,7 @@ break_loop:
 }

 static int nbd_co_receive_return_code(NBDClientSession *s, uint64_t handle,
-                                      Error **errp)
+                                      int *request_ret, Error **errp)
 {
     NBDReplyChunkIter iter;

@@ -639,12 +644,13 @@ static int nbd_co_receive_return_code(NBDClientSession *s, uint64_t handle,
     }

     error_propagate(errp, iter.err);
+    *request_ret = iter.request_ret;
     return iter.ret;
 }

 static int nbd_co_receive_cmdread_reply(NBDClientSession *s, uint64_t handle,
                                         uint64_t offset, QEMUIOVector *qiov,
-                                        Error **errp)
+                                        int *request_ret, Error **errp)
 {
     NBDReplyChunkIter iter;
     NBDReply reply;
@@ -669,7 +675,7 @@ static int nbd_co_receive_cmdread_reply(NBDClientSession *s, uint64_t handle,
                                                 offset, qiov, &local_err);
             if (ret < 0) {
                 s->quit = true;
-                nbd_iter_error(&iter, true, ret, &local_err);
+                nbd_iter_channel_error(&iter, ret, &local_err);
             }
             break;
         default:
@@ -679,7 +685,7 @@ static int nbd_co_receive_cmdread_reply(NBDClientSession *s, uint64_t handle,
                 error_setg(&local_err,
                            "Unexpected reply type: %d (%s) for CMD_READ",
                            chunk->type, nbd_reply_type_lookup(chunk->type));
-                nbd_iter_error(&iter, true, -EINVAL, &local_err);
+                nbd_iter_channel_error(&iter, -EINVAL, &local_err);
             }
         }

@@ -688,12 +694,14 @@ static int nbd_co_receive_cmdread_reply(NBDClientSession *s, uint64_t handle,
     }

     error_propagate(errp, iter.err);
+    *request_ret = iter.request_ret;
     return iter.ret;
 }

 static int nbd_co_receive_blockstatus_reply(NBDClientSession *s,
                                             uint64_t handle, uint64_t length,
-                                            NBDExtent *extent, Error **errp)
+                                            NBDExtent *extent,
+                                            int *request_ret, Error **errp)
 {
     NBDReplyChunkIter iter;
     NBDReply reply;
@@ -715,7 +723,7 @@ static int nbd_co_receive_blockstatus_reply(NBDClientSession *s,
             if (received) {
                 s->quit = true;
                 error_setg(&local_err, "Several BLOCK_STATUS chunks in reply");
-                nbd_iter_error(&iter, true, -EINVAL, &local_err);
+                nbd_iter_channel_error(&iter, -EINVAL, &local_err);
             }
             received = true;

@@ -724,7 +732,7 @@ static int nbd_co_receive_blockstatus_reply(NBDClientSession *s,
                                                 &local_err);
             if (ret < 0) {
                 s->quit = true;
-                nbd_iter_error(&iter, true, ret, &local_err);
+                nbd_iter_channel_error(&iter, ret, &local_err);
             }
             break;
         default:
@@ -734,7 +742,7 @@ static int nbd_co_receive_blockstatus_reply(NBDClientSession *s,
                            "Unexpected reply type: %d (%s) "
                            "for CMD_BLOCK_STATUS",
                            chunk->type, nbd_reply_type_lookup(chunk->type));
-                nbd_iter_error(&iter, true, -EINVAL, &local_err);
+                nbd_iter_channel_error(&iter, -EINVAL, &local_err);
             }
         }

@@ -749,14 +757,16 @@ static int nbd_co_receive_blockstatus_reply(NBDClientSession *s,
             iter.ret = -EIO;
         }
     }
+
     error_propagate(errp, iter.err);
+    *request_ret = iter.request_ret;
     return iter.ret;
 }

 static int nbd_co_request(BlockDriverState *bs, NBDRequest *request,
                           QEMUIOVector *write_qiov)
 {
-    int ret;
+    int ret, request_ret;
     Error *local_err = NULL;
     NBDClientSession *client = nbd_get_client_session(bs);

@@ -772,7 +782,8 @@ static int nbd_co_request(BlockDriverState *bs, NBDRequest *request,
         return ret;
     }

-    ret = nbd_co_receive_return_code(client, request->handle, &local_err);
+    ret = nbd_co_receive_return_code(client, request->handle,
+                                     &request_ret, &local_err);
     if (local_err) {
         trace_nbd_co_request_fail(request->from, request->len, request->handle,
                                   request->flags, request->type,
@@ -780,13 +791,13 @@ static int nbd_co_request(BlockDriverState *bs, NBDRequest *request,
                                   ret, error_get_pretty(local_err));
         error_free(local_err);
     }
-    return ret;
+    return ret ? ret : request_ret;
 }

 int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset,
                          uint64_t bytes, QEMUIOVector *qiov, int flags)
 {
-    int ret;
+    int ret, request_ret;
     Error *local_err = NULL;
     NBDClientSession *client = nbd_get_client_session(bs);
     NBDRequest request = {
@@ -807,7 +818,7 @@ int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset,
     }

     ret = nbd_co_receive_cmdread_reply(client, request.handle, offset, qiov,
-                                       &local_err);
+                                       &request_ret, &local_err);
     if (local_err) {
         trace_nbd_co_request_fail(request.from, request.len, request.handle,
                                   request.flags, request.type,
@@ -815,7 +826,7 @@ int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset,
                                   ret, error_get_pretty(local_err));
         error_free(local_err);
     }
-    return ret;
+    return ret ? ret : request_ret;
 }

 int nbd_client_co_pwritev(BlockDriverState *bs, uint64_t offset,
@@ -909,7 +920,7 @@ int coroutine_fn nbd_client_co_block_status(BlockDriverState *bs,
                                             int64_t *pnum, int64_t *map,
                                             BlockDriverState **file)
 {
-    int64_t ret;
+    int ret, request_ret;
     NBDExtent extent = { 0 };
     NBDClientSession *client = nbd_get_client_session(bs);
     Error *local_err = NULL;
@@ -934,7 +945,7 @@ int coroutine_fn nbd_client_co_block_status(BlockDriverState *bs,
     }

     ret = nbd_co_receive_blockstatus_reply(client, request.handle, bytes,
-                                           &extent, &local_err);
+                                           &extent, &request_ret, &local_err);
     if (local_err) {
         trace_nbd_co_request_fail(request.from, request.len, request.handle,
                                   request.flags, request.type,
@@ -942,8 +953,8 @@ int coroutine_fn nbd_client_co_block_status(BlockDriverState *bs,
                                   ret, error_get_pretty(local_err));
         error_free(local_err);
     }
-    if (ret < 0) {
-        return ret;
+    if (ret < 0 || request_ret < 0) {
+        return ret ? ret : request_ret;
     }

     assert(extent.length);
-- 
2.20.1

[Qemu-devel] [PULL 4/8] block/nbd: move connection code from block/nbd to block/nbd-client

[Eric Blake]

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Keep all connection code in one file, to be able to implement reconnect
in further patches.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20190201130138.94525-3-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: format tweak]
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 block/nbd-client.h |  2 +-
 block/nbd-client.c | 38 ++++++++++++++++++++++++++++++++++++--
 block/nbd.c        | 40 ++--------------------------------------
 3 files changed, 39 insertions(+), 41 deletions(-)

diff --git a/block/nbd-client.h b/block/nbd-client.h
index cfc90550b99..2f047ba6142 100644
--- a/block/nbd-client.h
+++ b/block/nbd-client.h
@@ -41,7 +41,7 @@ typedef struct NBDClientSession {
 NBDClientSession *nbd_get_client_session(BlockDriverState *bs);

 int nbd_client_init(BlockDriverState *bs,
-                    QIOChannelSocket *sock,
+                    SocketAddress *saddr,
                     const char *export_name,
                     QCryptoTLSCreds *tlscreds,
                     const char *hostname,
diff --git a/block/nbd-client.c b/block/nbd-client.c
index fd58cda2f17..80dc8cff473 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -991,8 +991,29 @@ void nbd_client_close(BlockDriverState *bs)
     nbd_teardown_connection(bs);
 }

+static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr,
+                                                  Error **errp)
+{
+    QIOChannelSocket *sioc;
+    Error *local_err = NULL;
+
+    sioc = qio_channel_socket_new();
+    qio_channel_set_name(QIO_CHANNEL(sioc), "nbd-client");
+
+    qio_channel_socket_connect_sync(sioc, saddr, &local_err);
+    if (local_err) {
+        object_unref(OBJECT(sioc));
+        error_propagate(errp, local_err);
+        return NULL;
+    }
+
+    qio_channel_set_delay(QIO_CHANNEL(sioc), false);
+
+    return sioc;
+}
+
 int nbd_client_init(BlockDriverState *bs,
-                    QIOChannelSocket *sioc,
+                    SocketAddress *saddr,
                     const char *export,
                     QCryptoTLSCreds *tlscreds,
                     const char *hostname,
@@ -1002,6 +1023,16 @@ int nbd_client_init(BlockDriverState *bs,
     NBDClientSession *client = nbd_get_client_session(bs);
     int ret;

+    /*
+     * establish TCP connection, return error if it fails
+     * TODO: Configurable retry-until-timeout behaviour.
+     */
+    QIOChannelSocket *sioc = nbd_establish_connection(saddr, errp);
+
+    if (!sioc) {
+        return -ECONNREFUSED;
+    }
+
     /* NBD handshake */
     logout("session init %s\n", export);
     qio_channel_set_blocking(QIO_CHANNEL(sioc), true, NULL);
@@ -1017,6 +1048,7 @@ int nbd_client_init(BlockDriverState *bs,
     g_free(client->info.name);
     if (ret < 0) {
         logout("Failed to negotiate with the NBD server\n");
+        object_unref(OBJECT(sioc));
         return ret;
     }
     if (x_dirty_bitmap && !client->info.base_allocation) {
@@ -1042,7 +1074,6 @@ int nbd_client_init(BlockDriverState *bs,
     qemu_co_mutex_init(&client->send_mutex);
     qemu_co_queue_init(&client->free_sema);
     client->sioc = sioc;
-    object_ref(OBJECT(client->sioc));

     if (!client->ioc) {
         client->ioc = QIO_CHANNEL(sioc);
@@ -1068,6 +1099,9 @@ int nbd_client_init(BlockDriverState *bs,
         NBDRequest request = { .type = NBD_CMD_DISC };

         nbd_send_request(client->ioc ?: QIO_CHANNEL(sioc), &request);
+
+        object_unref(OBJECT(sioc));
+
         return ret;
     }
 }
diff --git a/block/nbd.c b/block/nbd.c
index e87699fb73b..9db5eded892 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -295,30 +295,6 @@ NBDClientSession *nbd_get_client_session(BlockDriverState *bs)
     return &s->client;
 }

-static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr,
-                                                  Error **errp)
-{
-    QIOChannelSocket *sioc;
-    Error *local_err = NULL;
-
-    sioc = qio_channel_socket_new();
-    qio_channel_set_name(QIO_CHANNEL(sioc), "nbd-client");
-
-    qio_channel_socket_connect_sync(sioc,
-                                    saddr,
-                                    &local_err);
-    if (local_err) {
-        object_unref(OBJECT(sioc));
-        error_propagate(errp, local_err);
-        return NULL;
-    }
-
-    qio_channel_set_delay(QIO_CHANNEL(sioc), false);
-
-    return sioc;
-}
-
-
 static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp)
 {
     Object *obj;
@@ -394,7 +370,6 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
     BDRVNBDState *s = bs->opaque;
     QemuOpts *opts = NULL;
     Error *local_err = NULL;
-    QIOChannelSocket *sioc = NULL;
     QCryptoTLSCreds *tlscreds = NULL;
     const char *hostname = NULL;
     int ret = -EINVAL;
@@ -434,22 +409,11 @@ static int nbd_open(BlockDriverState *bs, QDict *options, int flags,
         hostname = s->saddr->u.inet.host;
     }

-    /* establish TCP connection, return error if it fails
-     * TODO: Configurable retry-until-timeout behaviour.
-     */
-    sioc = nbd_establish_connection(s->saddr, errp);
-    if (!sioc) {
-        ret = -ECONNREFUSED;
-        goto error;
-    }
-
     /* NBD handshake */
-    ret = nbd_client_init(bs, sioc, s->export, tlscreds, hostname,
+    ret = nbd_client_init(bs, s->saddr, s->export, tlscreds, hostname,
                           qemu_opt_get(opts, "x-dirty-bitmap"), errp);
+
  error:
-    if (sioc) {
-        object_unref(OBJECT(sioc));
-    }
     if (tlscreds) {
         object_unref(OBJECT(tlscreds));
     }
-- 
2.20.1

[Qemu-devel] [PULL 5/8] block/nbd-client: split connection from initialization

[Eric Blake]

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Split connection code to reuse it for reconnect.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190201130138.94525-4-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 block/nbd-client.c | 33 ++++++++++++++++++++++++---------
 1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/block/nbd-client.c b/block/nbd-client.c
index 80dc8cff473..d7d88297698 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -1012,13 +1012,13 @@ static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr,
     return sioc;
 }

-int nbd_client_init(BlockDriverState *bs,
-                    SocketAddress *saddr,
-                    const char *export,
-                    QCryptoTLSCreds *tlscreds,
-                    const char *hostname,
-                    const char *x_dirty_bitmap,
-                    Error **errp)
+static int nbd_client_connect(BlockDriverState *bs,
+                              SocketAddress *saddr,
+                              const char *export,
+                              QCryptoTLSCreds *tlscreds,
+                              const char *hostname,
+                              const char *x_dirty_bitmap,
+                              Error **errp)
 {
     NBDClientSession *client = nbd_get_client_session(bs);
     int ret;
@@ -1071,8 +1071,6 @@ int nbd_client_init(BlockDriverState *bs,
         bs->supported_zero_flags |= BDRV_REQ_MAY_UNMAP;
     }

-    qemu_co_mutex_init(&client->send_mutex);
-    qemu_co_queue_init(&client->free_sema);
     client->sioc = sioc;

     if (!client->ioc) {
@@ -1105,3 +1103,20 @@ int nbd_client_init(BlockDriverState *bs,
         return ret;
     }
 }
+
+int nbd_client_init(BlockDriverState *bs,
+                    SocketAddress *saddr,
+                    const char *export,
+                    QCryptoTLSCreds *tlscreds,
+                    const char *hostname,
+                    const char *x_dirty_bitmap,
+                    Error **errp)
+{
+    NBDClientSession *client = nbd_get_client_session(bs);
+
+    qemu_co_mutex_init(&client->send_mutex);
+    qemu_co_queue_init(&client->free_sema);
+
+    return nbd_client_connect(bs, saddr, export, tlscreds, hostname,
+                              x_dirty_bitmap, errp);
+}
-- 
2.20.1

[Qemu-devel] [PULL 6/8] block/nbd-client: fix nbd_reply_chunk_iter_receive

[Eric Blake]

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Use exported report, not the variable to be reused (should not really
matter).

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190201130138.94525-5-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 block/nbd-client.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/nbd-client.c b/block/nbd-client.c
index d7d88297698..65e56000681 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -602,7 +602,7 @@ static bool nbd_reply_chunk_iter_receive(NBDClientSession *s,
     }

     /* Do not execute the body of NBD_FOREACH_REPLY_CHUNK for simple reply. */
-    if (nbd_reply_is_simple(&s->reply) || s->quit) {
+    if (nbd_reply_is_simple(reply) || s->quit) {
         goto break_loop;
     }

-- 
2.20.1

[Qemu-devel] [PULL 7/8] block/nbd-client: don't check ioc

[Eric Blake]

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

We have several paranoid checks for ioc != NULL. But ioc may become
NULL only on close, which should not happen during requests handling.
Also, we check ioc only sometimes, not after each yield, which is
inconsistent. Let's drop these checks. However, for safety, let's leave
asserts instead.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190201130138.94525-6-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 block/nbd-client.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/block/nbd-client.c b/block/nbd-client.c
index 65e56000681..386c3feb14f 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -53,9 +53,7 @@ static void nbd_teardown_connection(BlockDriverState *bs)
 {
     NBDClientSession *client = nbd_get_client_session(bs);

-    if (!client->ioc) { /* Already closed */
-        return;
-    }
+    assert(client->ioc);

     /* finish any pending coroutines */
     qio_channel_shutdown(client->ioc,
@@ -154,10 +152,7 @@ static int nbd_co_send_request(BlockDriverState *bs,
         rc = -EIO;
         goto err;
     }
-    if (!s->ioc) {
-        rc = -EPIPE;
-        goto err;
-    }
+    assert(s->ioc);

     if (qiov) {
         qio_channel_set_cork(s->ioc, true);
@@ -429,10 +424,11 @@ static coroutine_fn int nbd_co_do_receive_one_chunk(
     s->requests[i].receiving = true;
     qemu_coroutine_yield();
     s->requests[i].receiving = false;
-    if (!s->ioc || s->quit) {
+    if (s->quit) {
         error_setg(errp, "Connection closed");
         return -EIO;
     }
+    assert(s->ioc);

     assert(s->reply.handle == handle);

@@ -982,9 +978,7 @@ void nbd_client_close(BlockDriverState *bs)
     NBDClientSession *client = nbd_get_client_session(bs);
     NBDRequest request = { .type = NBD_CMD_DISC };

-    if (client->ioc == NULL) {
-        return;
-    }
+    assert(client->ioc);

     nbd_send_request(client->ioc, &request);

-- 
2.20.1

[Qemu-devel] [PULL 8/8] block/nbd-client: rename read_reply_co to connection_co

[Eric Blake]

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

This coroutine will serve nbd reconnects, so, rename it to be something
more generic.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190201130138.94525-7-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 block/nbd-client.h |  4 ++--
 block/nbd-client.c | 24 ++++++++++++------------
 2 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/block/nbd-client.h b/block/nbd-client.h
index 2f047ba6142..d990207a5cb 100644
--- a/block/nbd-client.h
+++ b/block/nbd-client.h
@@ -20,7 +20,7 @@
 typedef struct {
     Coroutine *coroutine;
     uint64_t offset;        /* original offset of the request */
-    bool receiving;         /* waiting for read_reply_co? */
+    bool receiving;         /* waiting for connection_co? */
 } NBDClientRequest;

 typedef struct NBDClientSession {
@@ -30,7 +30,7 @@ typedef struct NBDClientSession {

     CoMutex send_mutex;
     CoQueue free_sema;
-    Coroutine *read_reply_co;
+    Coroutine *connection_co;
     int in_flight;

     NBDClientRequest requests[MAX_NBD_REQUESTS];
diff --git a/block/nbd-client.c b/block/nbd-client.c
index 386c3feb14f..f0ad54ce21d 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -59,7 +59,7 @@ static void nbd_teardown_connection(BlockDriverState *bs)
     qio_channel_shutdown(client->ioc,
                          QIO_CHANNEL_SHUTDOWN_BOTH,
                          NULL);
-    BDRV_POLL_WHILE(bs, client->read_reply_co);
+    BDRV_POLL_WHILE(bs, client->connection_co);

     nbd_client_detach_aio_context(bs);
     object_unref(OBJECT(client->sioc));
@@ -68,7 +68,7 @@ static void nbd_teardown_connection(BlockDriverState *bs)
     client->ioc = NULL;
 }

-static coroutine_fn void nbd_read_reply_entry(void *opaque)
+static coroutine_fn void nbd_connection_entry(void *opaque)
 {
     NBDClientSession *s = opaque;
     uint64_t i;
@@ -100,14 +100,14 @@ static coroutine_fn void nbd_read_reply_entry(void *opaque)
         }

         /* We're woken up again by the request itself.  Note that there
-         * is no race between yielding and reentering read_reply_co.  This
+         * is no race between yielding and reentering connection_co.  This
          * is because:
          *
          * - if the request runs on the same AioContext, it is only
          *   entered after we yield
          *
          * - if the request runs on a different AioContext, reentering
-         *   read_reply_co happens through a bottom half, which can only
+         *   connection_co happens through a bottom half, which can only
          *   run after we yield.
          */
         aio_co_wake(s->requests[i].coroutine);
@@ -116,7 +116,7 @@ static coroutine_fn void nbd_read_reply_entry(void *opaque)

     s->quit = true;
     nbd_recv_coroutines_wake_all(s);
-    s->read_reply_co = NULL;
+    s->connection_co = NULL;
     aio_wait_kick();
 }

@@ -420,7 +420,7 @@ static coroutine_fn int nbd_co_do_receive_one_chunk(
     }
     *request_ret = 0;

-    /* Wait until we're woken up by nbd_read_reply_entry.  */
+    /* Wait until we're woken up by nbd_connection_entry.  */
     s->requests[i].receiving = true;
     qemu_coroutine_yield();
     s->requests[i].receiving = false;
@@ -495,7 +495,7 @@ static coroutine_fn int nbd_co_do_receive_one_chunk(
 }

 /* nbd_co_receive_one_chunk
- * Read reply, wake up read_reply_co and set s->quit if needed.
+ * Read reply, wake up connection_co and set s->quit if needed.
  * Return value is a fatal error code or normal nbd reply error code
  */
 static coroutine_fn int nbd_co_receive_one_chunk(
@@ -509,15 +509,15 @@ static coroutine_fn int nbd_co_receive_one_chunk(
     if (ret < 0) {
         s->quit = true;
     } else {
-        /* For assert at loop start in nbd_read_reply_entry */
+        /* For assert at loop start in nbd_connection_entry */
         if (reply) {
             *reply = s->reply;
         }
         s->reply.handle = 0;
     }

-    if (s->read_reply_co) {
-        aio_co_wake(s->read_reply_co);
+    if (s->connection_co) {
+        aio_co_wake(s->connection_co);
     }

     return ret;
@@ -970,7 +970,7 @@ void nbd_client_attach_aio_context(BlockDriverState *bs,
 {
     NBDClientSession *client = nbd_get_client_session(bs);
     qio_channel_attach_aio_context(QIO_CHANNEL(client->ioc), new_context);
-    aio_co_schedule(new_context, client->read_reply_co);
+    aio_co_schedule(new_context, client->connection_co);
 }

 void nbd_client_close(BlockDriverState *bs)
@@ -1075,7 +1075,7 @@ static int nbd_client_connect(BlockDriverState *bs,
     /* Now that we're connected, set the socket to be non-blocking and
      * kick the reply mechanism.  */
     qio_channel_set_blocking(QIO_CHANNEL(sioc), false, NULL);
-    client->read_reply_co = qemu_coroutine_create(nbd_read_reply_entry, client);
+    client->connection_co = qemu_coroutine_create(nbd_connection_entry, client);
     nbd_client_attach_aio_context(bs, bdrv_get_aio_context(bs));

     logout("Established connection with NBD server\n");
-- 
2.20.1

Re: [Qemu-devel] [PULL 0/8] NBD patches for 2019-02-04

[no-reply]

Patchew URL: https://patchew.org/QEMU/20190205035704.26014-1-eblake@redhat.com/



Hi,

This series seems to have some coding style problems. See output below for
more information:

Subject: [Qemu-devel] [PULL 0/8] NBD patches for 2019-02-04
Type: series
Message-id: 20190205035704.26014-1-eblake@redhat.com

=== TEST SCRIPT BEGIN ===
#!/bin/bash
git config --local diff.renamelimit 0
git config --local diff.renames True
git config --local diff.algorithm histogram
./scripts/checkpatch.pl --mailback base..
=== TEST SCRIPT END ===

Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
From https://github.com/patchew-project/qemu
 t [tag update]            patchew/20190204204517.23698-1-philmd@redhat.com -> patchew/20190204204517.23698-1-philmd@redhat.com
 * [new tag]               patchew/20190205035704.26014-1-eblake@redhat.com -> patchew/20190205035704.26014-1-eblake@redhat.com
Switched to a new branch 'test'
9f22048c0a block/nbd-client: rename read_reply_co to connection_co
e81ab27f82 block/nbd-client: don't check ioc
ce55b4b331 block/nbd-client: fix nbd_reply_chunk_iter_receive
80c093f3b1 block/nbd-client: split connection from initialization
a24543ee7b block/nbd: move connection code from block/nbd to block/nbd-client
467a28dbf2 block/nbd-client: split channel errors from export errors
bd906b01ff nbd: generalize usage of nbd_read
3d3be1f9bc qemu-nbd: Deprecate qemu-nbd --partition

=== OUTPUT BEGIN ===
1/8 Checking commit 3d3be1f9bcc8 (qemu-nbd: Deprecate qemu-nbd --partition)
2/8 Checking commit bd906b01ffe8 (nbd: generalize usage of nbd_read)
ERROR: spaces required around that '*' (ctx:WxV)
#85: FILE: include/block/nbd.h:356:
+                                 uint##bits##_t *val,                   \
                                                 ^

total: 1 errors, 0 warnings, 386 lines checked

Patch 2/8 has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.

3/8 Checking commit 467a28dbf261 (block/nbd-client: split channel errors from export errors)
4/8 Checking commit a24543ee7b41 (block/nbd: move connection code from block/nbd to block/nbd-client)
5/8 Checking commit 80c093f3b180 (block/nbd-client: split connection from initialization)
6/8 Checking commit ce55b4b331f9 (block/nbd-client: fix nbd_reply_chunk_iter_receive)
7/8 Checking commit e81ab27f828e (block/nbd-client: don't check ioc)
8/8 Checking commit 9f22048c0a07 (block/nbd-client: rename read_reply_co to connection_co)
=== OUTPUT END ===

Test command exited with code: 1


The full log is available at
http://patchew.org/logs/20190205035704.26014-1-eblake@redhat.com/testing.checkpatch/?type=message.
---
Email generated automatically by Patchew [http://patchew.org/].
Please send your feedback to patchew-devel@redhat.com

Re: [Qemu-devel] [PULL 0/8] NBD patches for 2019-02-04

[no-reply]

Patchew URL: https://patchew.org/QEMU/20190205035704.26014-1-eblake@redhat.com/



Hi,

This series seems to have some coding style problems. See output below for
more information:

Message-id: 20190205035704.26014-1-eblake@redhat.com
Subject: [Qemu-devel] [PULL 0/8] NBD patches for 2019-02-04
Type: series

=== TEST SCRIPT BEGIN ===
#!/bin/bash
git config --local diff.renamelimit 0
git config --local diff.renames True
git config --local diff.algorithm histogram
./scripts/checkpatch.pl --mailback base..
=== TEST SCRIPT END ===

Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
From https://github.com/patchew-project/qemu
 * [new tag]         patchew/1549336101-17623-1-git-send-email-thuth@redhat.com -> patchew/1549336101-17623-1-git-send-email-thuth@redhat.com
 - [tag update]      patchew/20190204204517.23698-1-philmd@redhat.com -> patchew/20190204204517.23698-1-philmd@redhat.com
 * [new tag]         patchew/20190205035704.26014-1-eblake@redhat.com -> patchew/20190205035704.26014-1-eblake@redhat.com
Switched to a new branch 'test'
9f22048 block/nbd-client: rename read_reply_co to connection_co
e81ab27 block/nbd-client: don't check ioc
ce55b4b block/nbd-client: fix nbd_reply_chunk_iter_receive
80c093f block/nbd-client: split connection from initialization
a24543e block/nbd: move connection code from block/nbd to block/nbd-client
467a28d block/nbd-client: split channel errors from export errors
bd906b0 nbd: generalize usage of nbd_read
3d3be1f qemu-nbd: Deprecate qemu-nbd --partition

=== OUTPUT BEGIN ===
1/8 Checking commit 3d3be1f9bcc8 (qemu-nbd: Deprecate qemu-nbd --partition)
2/8 Checking commit bd906b01ffe8 (nbd: generalize usage of nbd_read)
ERROR: spaces required around that '*' (ctx:WxV)
#85: FILE: include/block/nbd.h:356:
+                                 uint##bits##_t *val,                   \
                                                 ^

total: 1 errors, 0 warnings, 386 lines checked

Patch 2/8 has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.

3/8 Checking commit 467a28dbf261 (block/nbd-client: split channel errors from export errors)
4/8 Checking commit a24543ee7b41 (block/nbd: move connection code from block/nbd to block/nbd-client)
5/8 Checking commit 80c093f3b180 (block/nbd-client: split connection from initialization)
6/8 Checking commit ce55b4b331f9 (block/nbd-client: fix nbd_reply_chunk_iter_receive)
7/8 Checking commit e81ab27f828e (block/nbd-client: don't check ioc)
8/8 Checking commit 9f22048c0a07 (block/nbd-client: rename read_reply_co to connection_co)
=== OUTPUT END ===

Test command exited with code: 1


The full log is available at
http://patchew.org/logs/20190205035704.26014-1-eblake@redhat.com/testing.checkpatch/?type=message.
---
Email generated automatically by Patchew [http://patchew.org/].
Please send your feedback to patchew-devel@redhat.com

Re: [Qemu-devel] [PULL 0/8] NBD patches for 2019-02-04

[no-reply]

Patchew URL: https://patchew.org/QEMU/20190205035704.26014-1-eblake@redhat.com/



Hi,

This series seems to have some coding style problems. See output below for
more information:

Subject: [Qemu-devel] [PULL 0/8] NBD patches for 2019-02-04
Message-id: 20190205035704.26014-1-eblake@redhat.com
Type: series

=== TEST SCRIPT BEGIN ===
#!/bin/bash
git config --local diff.renamelimit 0
git config --local diff.renames True
git config --local diff.algorithm histogram
./scripts/checkpatch.pl --mailback base..
=== TEST SCRIPT END ===

Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
From https://github.com/patchew-project/qemu
 - [tag update]      patchew/20190204204517.23698-1-philmd@redhat.com -> patchew/20190204204517.23698-1-philmd@redhat.com
 * [new tag]         patchew/20190205035704.26014-1-eblake@redhat.com -> patchew/20190205035704.26014-1-eblake@redhat.com
Submodule 'capstone' (https://git.qemu.org/git/capstone.git) registered for path 'capstone'
Submodule 'dtc' (https://git.qemu.org/git/dtc.git) registered for path 'dtc'
Submodule 'roms/QemuMacDrivers' (https://git.qemu.org/git/QemuMacDrivers.git) registered for path 'roms/QemuMacDrivers'
Submodule 'roms/SLOF' (https://git.qemu.org/git/SLOF.git) registered for path 'roms/SLOF'
Submodule 'roms/ipxe' (https://git.qemu.org/git/ipxe.git) registered for path 'roms/ipxe'
Submodule 'roms/openbios' (https://git.qemu.org/git/openbios.git) registered for path 'roms/openbios'
Submodule 'roms/openhackware' (https://git.qemu.org/git/openhackware.git) registered for path 'roms/openhackware'
Submodule 'roms/qemu-palcode' (https://git.qemu.org/git/qemu-palcode.git) registered for path 'roms/qemu-palcode'
Submodule 'roms/seabios' (https://git.qemu.org/git/seabios.git/) registered for path 'roms/seabios'
Submodule 'roms/seabios-hppa' (https://github.com/hdeller/seabios-hppa.git) registered for path 'roms/seabios-hppa'
Submodule 'roms/sgabios' (https://git.qemu.org/git/sgabios.git) registered for path 'roms/sgabios'
Submodule 'roms/skiboot' (https://git.qemu.org/git/skiboot.git) registered for path 'roms/skiboot'
Submodule 'roms/u-boot' (https://git.qemu.org/git/u-boot.git) registered for path 'roms/u-boot'
Submodule 'roms/u-boot-sam460ex' (https://git.qemu.org/git/u-boot-sam460ex.git) registered for path 'roms/u-boot-sam460ex'
Submodule 'tests/fp/berkeley-softfloat-3' (https://github.com/cota/berkeley-softfloat-3) registered for path 'tests/fp/berkeley-softfloat-3'
Submodule 'tests/fp/berkeley-testfloat-3' (https://github.com/cota/berkeley-testfloat-3) registered for path 'tests/fp/berkeley-testfloat-3'
Submodule 'ui/keycodemapdb' (https://git.qemu.org/git/keycodemapdb.git) registered for path 'ui/keycodemapdb'
Cloning into 'capstone'...
Submodule path 'capstone': checked out '22ead3e0bfdb87516656453336160e0a37b066bf'
Cloning into 'dtc'...
Submodule path 'dtc': checked out '88f18909db731a627456f26d779445f84e449536'
Cloning into 'roms/QemuMacDrivers'...
Submodule path 'roms/QemuMacDrivers': checked out '90c488d5f4a407342247b9ea869df1c2d9c8e266'
Cloning into 'roms/SLOF'...
Submodule path 'roms/SLOF': checked out 'a5b428e1c1eae703bdd62a3f527223c291ee3fdc'
Cloning into 'roms/ipxe'...
Submodule path 'roms/ipxe': checked out 'de4565cbe76ea9f7913a01f331be3ee901bb6e17'
Cloning into 'roms/openbios'...
Submodule path 'roms/openbios': checked out '441a84d3a642a10b948369c63f32367e8ff6395b'
Cloning into 'roms/openhackware'...
Submodule path 'roms/openhackware': checked out 'c559da7c8eec5e45ef1f67978827af6f0b9546f5'
Cloning into 'roms/qemu-palcode'...
Submodule path 'roms/qemu-palcode': checked out '51c237d7e20d05100eacadee2f61abc17e6bc097'
Cloning into 'roms/seabios'...
Submodule path 'roms/seabios': checked out 'a698c8995ffb2838296ec284fe3c4ad33dfca307'
Cloning into 'roms/seabios-hppa'...
Submodule path 'roms/seabios-hppa': checked out '1ef99a01572c2581c30e16e6fe69e9ea2ef92ce0'
Cloning into 'roms/sgabios'...
Submodule path 'roms/sgabios': checked out 'cbaee52287e5f32373181cff50a00b6c4ac9015a'
Cloning into 'roms/skiboot'...
Submodule path 'roms/skiboot': checked out 'e0ee24c27a172bcf482f6f2bc905e6211c134bcc'
Cloning into 'roms/u-boot'...
Submodule path 'roms/u-boot': checked out 'd85ca029f257b53a96da6c2fb421e78a003a9943'
Cloning into 'roms/u-boot-sam460ex'...
Submodule path 'roms/u-boot-sam460ex': checked out '60b3916f33e617a815973c5a6df77055b2e3a588'
Cloning into 'tests/fp/berkeley-softfloat-3'...
Submodule path 'tests/fp/berkeley-softfloat-3': checked out 'b64af41c3276f97f0e181920400ee056b9c88037'
Cloning into 'tests/fp/berkeley-testfloat-3'...
Submodule path 'tests/fp/berkeley-testfloat-3': checked out '5a59dcec19327396a011a17fd924aed4fec416b3'
Cloning into 'ui/keycodemapdb'...
Submodule path 'ui/keycodemapdb': checked out '6b3d716e2b6472eb7189d3220552280ef3d832ce'
Switched to a new branch 'test'
9f22048 block/nbd-client: rename read_reply_co to connection_co
e81ab27 block/nbd-client: don't check ioc
ce55b4b block/nbd-client: fix nbd_reply_chunk_iter_receive
80c093f block/nbd-client: split connection from initialization
a24543e block/nbd: move connection code from block/nbd to block/nbd-client
467a28d block/nbd-client: split channel errors from export errors
bd906b0 nbd: generalize usage of nbd_read
3d3be1f qemu-nbd: Deprecate qemu-nbd --partition

=== OUTPUT BEGIN ===
1/8 Checking commit 3d3be1f9bcc8 (qemu-nbd: Deprecate qemu-nbd --partition)
2/8 Checking commit bd906b01ffe8 (nbd: generalize usage of nbd_read)
ERROR: spaces required around that '*' (ctx:WxV)
#85: FILE: include/block/nbd.h:356:
+                                 uint##bits##_t *val,                   \
                                                 ^

total: 1 errors, 0 warnings, 386 lines checked

Patch 2/8 has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.

3/8 Checking commit 467a28dbf261 (block/nbd-client: split channel errors from export errors)
4/8 Checking commit a24543ee7b41 (block/nbd: move connection code from block/nbd to block/nbd-client)
5/8 Checking commit 80c093f3b180 (block/nbd-client: split connection from initialization)
6/8 Checking commit ce55b4b331f9 (block/nbd-client: fix nbd_reply_chunk_iter_receive)
7/8 Checking commit e81ab27f828e (block/nbd-client: don't check ioc)
8/8 Checking commit 9f22048c0a07 (block/nbd-client: rename read_reply_co to connection_co)
=== OUTPUT END ===

Test command exited with code: 1


The full log is available at
http://patchew.org/logs/20190205035704.26014-1-eblake@redhat.com/testing.checkpatch/?type=message.
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Re: [Qemu-devel] [PULL 0/8] NBD patches for 2019-02-04

[Eric Blake]

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On 2/4/19 10:08 PM, no-reply@patchew.org wrote:
> Patchew URL: https://patchew.org/QEMU/20190205035704.26014-1-eblake@redhat.com/
> 
> 
> 
> Hi,
> 
> This series seems to have some coding style problems. See output below for
> more information:
> 

> 2/8 Checking commit bd906b01ffe8 (nbd: generalize usage of nbd_read)
> ERROR: spaces required around that '*' (ctx:WxV)
> #85: FILE: include/block/nbd.h:356:
> +                                 uint##bits##_t *val,                   \
>                                                  ^
> 
> total: 1 errors, 0 warnings, 386 lines checked
> 
> Patch 2/8 has style problems, please review.  If any of these errors
> are false positives report them to the maintainer, see
> CHECKPATCH in MAINTAINERS.

False positive. Seeing past ## pasting in a macro is not trivial to fix
in checkpatch, so I'm intentionally ignoring this one.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org


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Re: [Qemu-devel] [PULL 0/8] NBD patches for 2019-02-04

[Peter Maydell]

On Tue, 5 Feb 2019 at 03:58, Eric Blake <eblake@redhat.com> wrote:
>
> The following changes since commit 773c4a6228fd910556cee2d477ee56c591a30000:
>
>   test-filter-mirror: pass UNIX domain socket through fd (2019-02-04 16:03:20 +0000)
>
> are available in the Git repository at:
>
>   https://repo.or.cz/qemu/ericb.git tags/pull-nbd-2019-02-04
>
> for you to fetch changes up to bc5a03350c220698229e7d6929dd242d5d358345:
>
>   block/nbd-client: rename read_reply_co to connection_co (2019-02-04 15:11:27 -0600)
>
> ----------------------------------------------------------------
> nbd patches for 2019-02-04
>
> - deprecate 'qemu-nbd --partition'
> - preparation for NBD reconnect, including better logging of read errors
>
> ----------------------------------------------------------------


Applied, thanks.

Please update the changelog at https://wiki.qemu.org/ChangeLog/4.0
for any user-visible changes.

-- PMM