Merge remote-tracking branch 'bonzini/nbd-for-anthony' into staging

* bonzini/nbd-for-anthony: (26 commits)
  nbd: add myself as maintainer
  qemu-nbd: throttle requests
  qemu-nbd: asynchronous operation
  qemu-nbd: add client pointer to NBDRequest
  qemu-nbd: move client handling to nbd.c
  qemu-nbd: use common main loop
  link the main loop and its dependencies into the tools
  qemu-nbd: introduce NBDRequest
  qemu-nbd: introduce NBDExport
  qemu-nbd: introduce nbd_do_receive_request
  qemu-nbd: more robust handling of invalid requests
  qemu-nbd: introduce nbd_do_send_reply
  qemu-nbd: simplify nbd_trip
  move corking functions to osdep.c
  qemu-nbd: remove data_size argument to nbd_trip
  qemu-nbd: remove offset argument to nbd_trip
  Update ioctl order in nbd_init() to detect EBUSY
  nbd: add support for NBD_CMD_TRIM
  nbd: add support for NBD_CMD_FLUSH
  nbd: add support for NBD_CMD_FLAG_FUA
  ...

1 files changed, 346 insertions, 93 deletions

diff --git a/nbd.c b/nbd.c
index de880fe3c6..567e94e27a 100644
--- a/nbd.c
+++ b/nbd.c
@@ -18,6 +18,9 @@
 
 #include "nbd.h"
 #include "block.h"
+#include "block_int.h"
+
+#include "qemu-coroutine.h"
 
 #include <errno.h>
 #include <string.h>
@@ -35,6 +38,7 @@
 #endif
 
 #include "qemu_socket.h"
+#include "qemu-queue.h"
 
 //#define DEBUG_NBD
 
@@ -81,6 +85,14 @@ size_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read)
 {
     size_t offset = 0;
 
+    if (qemu_in_coroutine()) {
+        if (do_read) {
+            return qemu_co_recv(fd, buffer, size);
+        } else {
+            return qemu_co_send(fd, buffer, size);
+        }
+    }
+
     while (offset < size) {
         ssize_t len;
 
@@ -178,7 +190,7 @@ int unix_socket_outgoing(const char *path)
                   Request (type == 2)
 */
 
-int nbd_negotiate(int csock, off_t size, uint32_t flags)
+static int nbd_send_negotiate(int csock, off_t size, uint32_t flags)
 {
     char buf[8 + 8 + 8 + 128];
 
@@ -194,7 +206,9 @@ int nbd_negotiate(int csock, off_t size, uint32_t flags)
     memcpy(buf, "NBDMAGIC", 8);
     cpu_to_be64w((uint64_t*)(buf + 8), 0x00420281861253LL);
     cpu_to_be64w((uint64_t*)(buf + 16), size);
-    cpu_to_be32w((uint32_t*)(buf + 24), flags | NBD_FLAG_HAS_FLAGS);
+    cpu_to_be32w((uint32_t*)(buf + 24),
+                 flags | NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |
+                 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA);
     memset(buf + 28, 0, 124);
 
     if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {
@@ -348,6 +362,15 @@ int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags,
 #ifdef __linux__
 int nbd_init(int fd, int csock, uint32_t flags, off_t size, size_t blocksize)
 {
+    TRACE("Setting NBD socket");
+
+    if (ioctl(fd, NBD_SET_SOCK, csock) == -1) {
+        int serrno = errno;
+        LOG("Failed to set NBD socket");
+        errno = serrno;
+        return -1;
+    }
+
     TRACE("Setting block size to %lu", (unsigned long)blocksize);
 
     if (ioctl(fd, NBD_SET_BLKSIZE, blocksize) == -1) {
@@ -386,24 +409,6 @@ int nbd_init(int fd, int csock, uint32_t flags, off_t size, size_t blocksize)
         return -1;
     }
 
-    TRACE("Clearing NBD socket");
-
-    if (ioctl(fd, NBD_CLEAR_SOCK) == -1) {
-        int serrno = errno;
-        LOG("Failed clearing NBD socket");
-        errno = serrno;
-        return -1;
-    }
-
-    TRACE("Setting NBD socket");
-
-    if (ioctl(fd, NBD_SET_SOCK, csock) == -1) {
-        int serrno = errno;
-        LOG("Failed to set NBD socket");
-        errno = serrno;
-        return -1;
-    }
-
     TRACE("Negotiation ended");
 
     return 0;
@@ -582,121 +587,369 @@ static int nbd_send_reply(int csock, struct nbd_reply *reply)
     return 0;
 }
 
-int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset,
-             off_t *offset, uint32_t nbdflags, uint8_t *data, int data_size)
+#define MAX_NBD_REQUESTS 16
+
+typedef struct NBDRequest NBDRequest;
+
+struct NBDRequest {
+    QSIMPLEQ_ENTRY(NBDRequest) entry;
+    NBDClient *client;
+    uint8_t *data;
+};
+
+struct NBDExport {
+    BlockDriverState *bs;
+    off_t dev_offset;
+    off_t size;
+    uint32_t nbdflags;
+    QSIMPLEQ_HEAD(, NBDRequest) requests;
+};
+
+struct NBDClient {
+    int refcount;
+    void (*close)(NBDClient *client);
+
+    NBDExport *exp;
+    int sock;
+
+    Coroutine *recv_coroutine;
+
+    CoMutex send_lock;
+    Coroutine *send_coroutine;
+
+    int nb_requests;
+};
+
+static void nbd_client_get(NBDClient *client)
 {
-    struct nbd_request request;
-    struct nbd_reply reply;
+    client->refcount++;
+}
 
-    TRACE("Reading request.");
+static void nbd_client_put(NBDClient *client)
+{
+    if (--client->refcount == 0) {
+        g_free(client);
+    }
+}
 
-    if (nbd_receive_request(csock, &request) == -1)
-        return -1;
+static void nbd_client_close(NBDClient *client)
+{
+    qemu_set_fd_handler2(client->sock, NULL, NULL, NULL, NULL);
+    close(client->sock);
+    client->sock = -1;
+    if (client->close) {
+        client->close(client);
+    }
+    nbd_client_put(client);
+}
+
+static NBDRequest *nbd_request_get(NBDClient *client)
+{
+    NBDRequest *req;
+    NBDExport *exp = client->exp;
 
-    if (request.len + NBD_REPLY_SIZE > data_size) {
+    assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
+    client->nb_requests++;
+
+    if (QSIMPLEQ_EMPTY(&exp->requests)) {
+        req = g_malloc0(sizeof(NBDRequest));
+        req->data = qemu_blockalign(exp->bs, NBD_BUFFER_SIZE);
+    } else {
+        req = QSIMPLEQ_FIRST(&exp->requests);
+        QSIMPLEQ_REMOVE_HEAD(&exp->requests, entry);
+    }
+    nbd_client_get(client);
+    req->client = client;
+    return req;
+}
+
+static void nbd_request_put(NBDRequest *req)
+{
+    NBDClient *client = req->client;
+    QSIMPLEQ_INSERT_HEAD(&client->exp->requests, req, entry);
+    if (client->nb_requests-- == MAX_NBD_REQUESTS) {
+        qemu_notify_event();
+    }
+    nbd_client_put(client);
+}
+
+NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset,
+                          off_t size, uint32_t nbdflags)
+{
+    NBDExport *exp = g_malloc0(sizeof(NBDExport));
+    QSIMPLEQ_INIT(&exp->requests);
+    exp->bs = bs;
+    exp->dev_offset = dev_offset;
+    exp->nbdflags = nbdflags;
+    exp->size = size == -1 ? exp->bs->total_sectors * 512 : size;
+    return exp;
+}
+
+void nbd_export_close(NBDExport *exp)
+{
+    while (!QSIMPLEQ_EMPTY(&exp->requests)) {
+        NBDRequest *first = QSIMPLEQ_FIRST(&exp->requests);
+        QSIMPLEQ_REMOVE_HEAD(&exp->requests, entry);
+        qemu_vfree(first->data);
+        g_free(first);
+    }
+
+    bdrv_close(exp->bs);
+    g_free(exp);
+}
+
+static int nbd_can_read(void *opaque);
+static void nbd_read(void *opaque);
+static void nbd_restart_write(void *opaque);
+
+static int nbd_co_send_reply(NBDRequest *req, struct nbd_reply *reply,
+                             int len)
+{
+    NBDClient *client = req->client;
+    int csock = client->sock;
+    int rc, ret;
+
+    qemu_co_mutex_lock(&client->send_lock);
+    qemu_set_fd_handler2(csock, nbd_can_read, nbd_read,
+                         nbd_restart_write, client);
+    client->send_coroutine = qemu_coroutine_self();
+
+    if (!len) {
+        rc = nbd_send_reply(csock, reply);
+        if (rc == -1) {
+            rc = -errno;
+        }
+    } else {
+        socket_set_cork(csock, 1);
+        rc = nbd_send_reply(csock, reply);
+        if (rc != -1) {
+            ret = qemu_co_send(csock, req->data, len);
+            if (ret != len) {
+                errno = EIO;
+                rc = -1;
+            }
+        }
+        if (rc == -1) {
+            rc = -errno;
+        }
+        socket_set_cork(csock, 0);
+    }
+
+    client->send_coroutine = NULL;
+    qemu_set_fd_handler2(csock, nbd_can_read, nbd_read, NULL, client);
+    qemu_co_mutex_unlock(&client->send_lock);
+    return rc;
+}
+
+static int nbd_co_receive_request(NBDRequest *req, struct nbd_request *request)
+{
+    NBDClient *client = req->client;
+    int csock = client->sock;
+    int rc;
+
+    client->recv_coroutine = qemu_coroutine_self();
+    if (nbd_receive_request(csock, request) == -1) {
+        rc = -EIO;
+        goto out;
+    }
+
+    if (request->len > NBD_BUFFER_SIZE) {
         LOG("len (%u) is larger than max len (%u)",
-            request.len + NBD_REPLY_SIZE, data_size);
-        errno = EINVAL;
-        return -1;
+            request->len, NBD_BUFFER_SIZE);
+        rc = -EINVAL;
+        goto out;
     }
 
-    if ((request.from + request.len) < request.from) {
+    if ((request->from + request->len) < request->from) {
         LOG("integer overflow detected! "
             "you're probably being attacked");
-        errno = EINVAL;
-        return -1;
+        rc = -EINVAL;
+        goto out;
     }
 
-    if ((request.from + request.len) > size) {
-            LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64
-            ", Offset: %" PRIu64 "\n",
-                    request.from, request.len, (uint64_t)size, dev_offset);
-        LOG("requested operation past EOF--bad client?");
-        errno = EINVAL;
-        return -1;
+    TRACE("Decoding type");
+
+    if ((request->type & NBD_CMD_MASK_COMMAND) == NBD_CMD_WRITE) {
+        TRACE("Reading %u byte(s)", request->len);
+
+        if (qemu_co_recv(csock, req->data, request->len) != request->len) {
+            LOG("reading from socket failed");
+            rc = -EIO;
+            goto out;
+        }
     }
+    rc = 0;
 
-    TRACE("Decoding type");
+out:
+    client->recv_coroutine = NULL;
+    return rc;
+}
+
+static void nbd_trip(void *opaque)
+{
+    NBDClient *client = opaque;
+    NBDRequest *req = nbd_request_get(client);
+    NBDExport *exp = client->exp;
+    struct nbd_request request;
+    struct nbd_reply reply;
+    int ret;
+
+    TRACE("Reading request.");
+
+    ret = nbd_co_receive_request(req, &request);
+    if (ret == -EIO) {
+        goto out;
+    }
 
     reply.handle = request.handle;
     reply.error = 0;
 
-    switch (request.type) {
+    if (ret < 0) {
+        reply.error = -ret;
+        goto error_reply;
+    }
+
+    if ((request.from + request.len) > exp->size) {
+            LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64
+            ", Offset: %" PRIu64 "\n",
+                    request.from, request.len,
+                    (uint64_t)exp->size, exp->dev_offset);
+        LOG("requested operation past EOF--bad client?");
+        goto invalid_request;
+    }
+
+    switch (request.type & NBD_CMD_MASK_COMMAND) {
     case NBD_CMD_READ:
         TRACE("Request type is READ");
 
-        if (bdrv_read(bs, (request.from + dev_offset) / 512,
-                  data + NBD_REPLY_SIZE,
-                  request.len / 512) == -1) {
+        ret = bdrv_read(exp->bs, (request.from + exp->dev_offset) / 512,
+                        req->data, request.len / 512);
+        if (ret < 0) {
             LOG("reading from file failed");
-            errno = EINVAL;
-            return -1;
+            reply.error = -ret;
+            goto error_reply;
         }
-        *offset += request.len;
 
         TRACE("Read %u byte(s)", request.len);
-
-        /* Reply
-           [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)
-           [ 4 ..  7]    error   (0 == no error)
-           [ 7 .. 15]    handle
-         */
-
-        cpu_to_be32w((uint32_t*)data, NBD_REPLY_MAGIC);
-        cpu_to_be32w((uint32_t*)(data + 4), reply.error);
-        cpu_to_be64w((uint64_t*)(data + 8), reply.handle);
-
-        TRACE("Sending data to client");
-
-        if (write_sync(csock, data,
-                   request.len + NBD_REPLY_SIZE) !=
-                   request.len + NBD_REPLY_SIZE) {
-            LOG("writing to socket failed");
-            errno = EINVAL;
-            return -1;
-        }
+        if (nbd_co_send_reply(req, &reply, request.len) < 0)
+            goto out;
         break;
     case NBD_CMD_WRITE:
         TRACE("Request type is WRITE");
 
-        TRACE("Reading %u byte(s)", request.len);
-
-        if (read_sync(csock, data, request.len) != request.len) {
-            LOG("reading from socket failed");
-            errno = EINVAL;
-            return -1;
+        if (exp->nbdflags & NBD_FLAG_READ_ONLY) {
+            TRACE("Server is read-only, return error");
+            reply.error = EROFS;
+            goto error_reply;
         }
 
-        if (nbdflags & NBD_FLAG_READ_ONLY) {
-            TRACE("Server is read-only, return error");
-            reply.error = 1;
-        } else {
-            TRACE("Writing to device");
+        TRACE("Writing to device");
 
-            if (bdrv_write(bs, (request.from + dev_offset) / 512,
-                       data, request.len / 512) == -1) {
-                LOG("writing to file failed");
-                errno = EINVAL;
-                return -1;
-            }
+        ret = bdrv_write(exp->bs, (request.from + exp->dev_offset) / 512,
+                         req->data, request.len / 512);
+        if (ret < 0) {
+            LOG("writing to file failed");
+            reply.error = -ret;
+            goto error_reply;
+        }
 
-            *offset += request.len;
+        if (request.type & NBD_CMD_FLAG_FUA) {
+            ret = bdrv_co_flush(exp->bs);
+            if (ret < 0) {
+                LOG("flush failed");
+                reply.error = -ret;
+                goto error_reply;
+            }
         }
 
-        if (nbd_send_reply(csock, &reply) == -1)
-            return -1;
+        if (nbd_co_send_reply(req, &reply, 0) < 0)
+            goto out;
         break;
     case NBD_CMD_DISC:
         TRACE("Request type is DISCONNECT");
         errno = 0;
-        return 1;
+        goto out;
+    case NBD_CMD_FLUSH:
+        TRACE("Request type is FLUSH");
+
+        ret = bdrv_co_flush(exp->bs);
+        if (ret < 0) {
+            LOG("flush failed");
+            reply.error = -ret;
+        }
+
+        if (nbd_co_send_reply(req, &reply, 0) < 0)
+            goto out;
+        break;
+    case NBD_CMD_TRIM:
+        TRACE("Request type is TRIM");
+        ret = bdrv_co_discard(exp->bs, (request.from + exp->dev_offset) / 512,
+                              request.len / 512);
+        if (ret < 0) {
+            LOG("discard failed");
+            reply.error = -ret;
+        }
+        if (nbd_co_send_reply(req, &reply, 0) < 0)
+            goto out;
+        break;
     default:
         LOG("invalid request type (%u) received", request.type);
-        errno = EINVAL;
-        return -1;
+    invalid_request:
+        reply.error = -EINVAL;
+    error_reply:
+        if (nbd_co_send_reply(req, &reply, 0) == -1)
+            goto out;
+        break;
     }
 
     TRACE("Request/Reply complete");
 
-    return 0;
+    nbd_request_put(req);
+    return;
+
+out:
+    nbd_request_put(req);
+    nbd_client_close(client);
+}
+
+static int nbd_can_read(void *opaque)
+{
+    NBDClient *client = opaque;
+
+    return client->recv_coroutine || client->nb_requests < MAX_NBD_REQUESTS;
+}
+
+static void nbd_read(void *opaque)
+{
+    NBDClient *client = opaque;
+
+    if (client->recv_coroutine) {
+        qemu_coroutine_enter(client->recv_coroutine, NULL);
+    } else {
+        qemu_coroutine_enter(qemu_coroutine_create(nbd_trip), client);
+    }
+}
+
+static void nbd_restart_write(void *opaque)
+{
+    NBDClient *client = opaque;
+
+    qemu_coroutine_enter(client->send_coroutine, NULL);
+}
+
+NBDClient *nbd_client_new(NBDExport *exp, int csock,
+                          void (*close)(NBDClient *))
+{
+    NBDClient *client;
+    if (nbd_send_negotiate(csock, exp->size, exp->nbdflags) == -1) {
+        return NULL;
+    }
+    client = g_malloc0(sizeof(NBDClient));
+    client->refcount = 1;
+    client->exp = exp;
+    client->sock = csock;
+    client->close = close;
+    qemu_co_mutex_init(&client->send_lock);
+    qemu_set_fd_handler2(csock, nbd_can_read, nbd_read, NULL, client);
+    return client;
 }