Commit 09d0726c authored by Anthony Liguori's avatar Anthony Liguori
Browse files

Merge remote-tracking branch 'bonzini/nbd-next' into staging 

* bonzini/nbd-next:
  nbd: add nbd_export_get_blockdev
  nbd: negotiate with named exports
  nbd: register named exports
  qemu-nbd: rewrite termination conditions to use a state machine
  nbd: add notification for closing an NBDExport
  nbd: track clients into NBDExport
  nbd: add reference counting to NBDExport
  nbd: do not leak nbd_trip coroutines when a connection is torn down
  nbd: make refcount interface public
  nbd: do not close BlockDriverState in nbd_export_close
  nbd: pass NBDClient to nbd_send_negotiate
  nbd: add more constants
parents d3e8f957 125afda8

nbd.c

+325 −71
Original line number Diff line number Diff line
@@ -57,9 +57,12 @@ 


/* This is all part of the "official" NBD API */



#define NBD_REQUEST_SIZE        (4 + 4 + 8 + 8 + 4)

#define NBD_REPLY_SIZE          (4 + 4 + 8)

#define NBD_REQUEST_MAGIC       0x25609513

#define NBD_REPLY_MAGIC         0x67446698

#define NBD_OPTS_MAGIC          0x49484156454F5054LL

#define NBD_CLIENT_MAGIC        0x0000420281861253LL



#define NBD_SET_SOCK            _IO(0xab, 0)

#define NBD_SET_BLKSIZE         _IO(0xab, 1)
@@ -75,6 +78,49 @@ 


#define NBD_OPT_EXPORT_NAME     (1 << 0)



/* Definitions for opaque data types */



typedef struct NBDRequest NBDRequest;



struct NBDRequest {

    QSIMPLEQ_ENTRY(NBDRequest) entry;

    NBDClient *client;

    uint8_t *data;

};



struct NBDExport {

    int refcount;

    void (*close)(NBDExport *exp);



    BlockDriverState *bs;

    char *name;

    off_t dev_offset;

    off_t size;

    uint32_t nbdflags;

    QTAILQ_HEAD(, NBDClient) clients;

    QSIMPLEQ_HEAD(, NBDRequest) requests;

    QTAILQ_ENTRY(NBDExport) next;

};



static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);



struct NBDClient {

    int refcount;

    void (*close)(NBDClient *client);



    NBDExport *exp;

    int sock;



    Coroutine *recv_coroutine;



    CoMutex send_lock;

    Coroutine *send_coroutine;



    QTAILQ_ENTRY(NBDClient) next;

    int nb_requests;

    bool closing;

};



/* That's all folks */



ssize_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read)
@@ -192,11 +238,23 @@ int unix_socket_outgoing(const char *path) 
    return unix_connect(path);

}



/* Basic flow

/* Basic flow for negotiation



   Server         Client



   Negotiate



   or



   Server         Client

   Negotiate #1

                  Option

   Negotiate #2



   ----



   followed by



   Server         Client

                  Request

   Response

                  Request
@@ -204,18 +262,111 @@ int unix_socket_outgoing(const char *path) 
                  ...

   ...

                  Request (type == 2)



*/



static int nbd_send_negotiate(int csock, off_t size, uint32_t flags)

static int nbd_receive_options(NBDClient *client)

{

    int csock = client->sock;

    char name[256];

    uint32_t tmp, length;

    uint64_t magic;

    int rc;



    /* Client sends:

        [ 0 ..   3]   reserved (0)

        [ 4 ..  11]   NBD_OPTS_MAGIC

        [12 ..  15]   NBD_OPT_EXPORT_NAME

        [16 ..  19]   length

        [20 ..  xx]   export name (length bytes)

     */



    rc = -EINVAL;

    if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {

        LOG("read failed");

        goto fail;

    }

    TRACE("Checking reserved");

    if (tmp != 0) {

        LOG("Bad reserved received");

        goto fail;

    }



    if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) {

        LOG("read failed");

        goto fail;

    }

    TRACE("Checking reserved");

    if (magic != be64_to_cpu(NBD_OPTS_MAGIC)) {

        LOG("Bad magic received");

        goto fail;

    }



    if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) {

        LOG("read failed");

        goto fail;

    }

    TRACE("Checking option");

    if (tmp != be32_to_cpu(NBD_OPT_EXPORT_NAME)) {

        LOG("Bad option received");

        goto fail;

    }



    if (read_sync(csock, &length, sizeof(length)) != sizeof(length)) {

        LOG("read failed");

        goto fail;

    }

    TRACE("Checking length");

    length = be32_to_cpu(length);

    if (length > 255) {

        LOG("Bad length received");

        goto fail;

    }

    if (read_sync(csock, name, length) != length) {

        LOG("read failed");

        goto fail;

    }

    name[length] = '\0';



    client->exp = nbd_export_find(name);

    if (!client->exp) {

        LOG("export not found");

        goto fail;

    }



    QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);

    nbd_export_get(client->exp);



    TRACE("Option negotiation succeeded.");

    rc = 0;

fail:

    return rc;

}



static int nbd_send_negotiate(NBDClient *client)

{

    int csock = client->sock;

    char buf[8 + 8 + 8 + 128];

    int rc;

    const int myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM |

                         NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA);



    /* Negotiate

    /* Negotiation header without options:

        [ 0 ..   7]   passwd       ("NBDMAGIC")

        [ 8 ..  15]   magic    (0x00420281861253)

        [ 8 ..  15]   magic        (NBD_CLIENT_MAGIC)

        [16 ..  23]   size

        [24 ..  27]   flags

        [24 ..  25]   server flags (0)

        [24 ..  27]   export flags

        [28 .. 151]   reserved     (0)



       Negotiation header with options, part 1:

        [ 0 ..   7]   passwd       ("NBDMAGIC")

        [ 8 ..  15]   magic        (NBD_OPTS_MAGIC)

        [16 ..  17]   server flags (0)



       part 2 (after options are sent):

        [18 ..  25]   size

        [26 ..  27]   export flags

        [28 .. 151]   reserved     (0)

     */
@@ -224,17 +375,40 @@ static int nbd_send_negotiate(int csock, off_t size, uint32_t flags) 


    TRACE("Beginning negotiation.");

    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 | NBD_FLAG_SEND_TRIM |

                 NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA);

    if (client->exp) {

        assert ((client->exp->nbdflags & ~65535) == 0);

        cpu_to_be64w((uint64_t*)(buf + 8), NBD_CLIENT_MAGIC);

        cpu_to_be64w((uint64_t*)(buf + 16), client->exp->size);

        cpu_to_be16w((uint16_t*)(buf + 26), client->exp->nbdflags | myflags);

    } else {

        cpu_to_be64w((uint64_t*)(buf + 8), NBD_OPTS_MAGIC);

    }

    memset(buf + 28, 0, 124);



    if (client->exp) {

        if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) {

            LOG("write failed");

            goto fail;

        }

    } else {

        if (write_sync(csock, buf, 18) != 18) {

            LOG("write failed");

            goto fail;

        }

        rc = nbd_receive_options(client);

        if (rc < 0) {

            LOG("option negotiation failed");

            goto fail;

        }



        assert ((client->exp->nbdflags & ~65535) == 0);

        cpu_to_be64w((uint64_t*)(buf + 18), client->exp->size);

        cpu_to_be16w((uint16_t*)(buf + 26), client->exp->nbdflags | myflags);

        if (write_sync(csock, buf + 18, sizeof(buf) - 18) != sizeof(buf) - 18) {

            LOG("write failed");

            goto fail;

        }

    }



    TRACE("Negotiation succeeded.");

    rc = 0;
@@ -295,7 +469,7 @@ int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags, 
        uint32_t namesize;



        TRACE("Checking magic (opts_magic)");

        if (magic != 0x49484156454F5054LL) {

        if (magic != NBD_OPTS_MAGIC) {

            LOG("Bad magic received");

            goto fail;

        }
@@ -334,7 +508,7 @@ int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags, 
    } else {

        TRACE("Checking magic (cli_magic)");



        if (magic != 0x00420281861253LL) {

        if (magic != NBD_CLIENT_MAGIC) {

            LOG("Bad magic received");

            goto fail;

        }
@@ -477,7 +651,7 @@ int nbd_client(int fd) 


ssize_t nbd_send_request(int csock, struct nbd_request *request)

{

    uint8_t buf[4 + 4 + 8 + 8 + 4];

    uint8_t buf[NBD_REQUEST_SIZE];

    ssize_t ret;



    cpu_to_be32w((uint32_t*)buf, NBD_REQUEST_MAGIC);
@@ -504,7 +678,7 @@ ssize_t nbd_send_request(int csock, struct nbd_request *request) 


static ssize_t nbd_receive_request(int csock, struct nbd_request *request)

{

    uint8_t buf[4 + 4 + 8 + 8 + 4];

    uint8_t buf[NBD_REQUEST_SIZE];

    uint32_t magic;

    ssize_t ret;
@@ -582,7 +756,7 @@ ssize_t nbd_receive_reply(int csock, struct nbd_reply *reply) 


static ssize_t nbd_send_reply(int csock, struct nbd_reply *reply)

{

    uint8_t buf[4 + 4 + 8];

    uint8_t buf[NBD_REPLY_SIZE];

    ssize_t ret;



    /* Reply
@@ -610,58 +784,47 @@ static ssize_t nbd_send_reply(int csock, struct nbd_reply *reply) 


#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)

void nbd_client_get(NBDClient *client)

{

    client->refcount++;

}



static void nbd_client_put(NBDClient *client)

void nbd_client_put(NBDClient *client)

{

    if (--client->refcount == 0) {

        /* The last reference should be dropped by client->close,

         * which is called by nbd_client_close.

         */

        assert(client->closing);



        qemu_set_fd_handler2(client->sock, NULL, NULL, NULL, NULL);

        close(client->sock);

        client->sock = -1;

        if (client->exp) {

            QTAILQ_REMOVE(&client->exp->clients, client, next);

            nbd_export_put(client->exp);

        }

        g_free(client);

    }

}



static void nbd_client_close(NBDClient *client)

void nbd_client_close(NBDClient *client)

{

    qemu_set_fd_handler2(client->sock, NULL, NULL, NULL, NULL);

    close(client->sock);

    client->sock = -1;

    if (client->closing) {

        return;

    }



    client->closing = true;



    /* Force requests to finish.  They will drop their own references,

     * then we'll close the socket and free the NBDClient.

     */

    shutdown(client->sock, 2);



    /* Also tell the client, so that they release their reference.  */

    if (client->close) {

        client->close(client);

    }

    nbd_client_put(client);

}



static NBDRequest *nbd_request_get(NBDClient *client)
@@ -695,19 +858,86 @@ static void nbd_request_put(NBDRequest *req) 
}



NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset,

                          off_t size, uint32_t nbdflags)

                          off_t size, uint32_t nbdflags,

                          void (*close)(NBDExport *))

{

    NBDExport *exp = g_malloc0(sizeof(NBDExport));

    QSIMPLEQ_INIT(&exp->requests);

    exp->refcount = 1;

    QTAILQ_INIT(&exp->clients);

    exp->bs = bs;

    exp->dev_offset = dev_offset;

    exp->nbdflags = nbdflags;

    exp->size = size == -1 ? bdrv_getlength(bs) : size;

    exp->close = close;

    return exp;

}



NBDExport *nbd_export_find(const char *name)

{

    NBDExport *exp;

    QTAILQ_FOREACH(exp, &exports, next) {

        if (strcmp(name, exp->name) == 0) {

            return exp;

        }

    }



    return NULL;

}



void nbd_export_set_name(NBDExport *exp, const char *name)

{

    if (exp->name == name) {

        return;

    }



    nbd_export_get(exp);

    if (exp->name != NULL) {

        g_free(exp->name);

        exp->name = NULL;

        QTAILQ_REMOVE(&exports, exp, next);

        nbd_export_put(exp);

    }

    if (name != NULL) {

        nbd_export_get(exp);

        exp->name = g_strdup(name);

        QTAILQ_INSERT_TAIL(&exports, exp, next);

    }

    nbd_export_put(exp);

}



void nbd_export_close(NBDExport *exp)

{

    NBDClient *client, *next;



    nbd_export_get(exp);

    QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) {

        nbd_client_close(client);

    }

    nbd_export_set_name(exp, NULL);

    nbd_export_put(exp);

}



void nbd_export_get(NBDExport *exp)

{

    assert(exp->refcount > 0);

    exp->refcount++;

}



void nbd_export_put(NBDExport *exp)

{

    assert(exp->refcount > 0);

    if (exp->refcount == 1) {

        nbd_export_close(exp);

    }



    if (--exp->refcount == 0) {

        assert(exp->name == NULL);



        if (exp->close) {

            exp->close(exp);

        }



        while (!QSIMPLEQ_EMPTY(&exp->requests)) {

            NBDRequest *first = QSIMPLEQ_FIRST(&exp->requests);

            QSIMPLEQ_REMOVE_HEAD(&exp->requests, entry);
@@ -715,9 +945,23 @@ void nbd_export_close(NBDExport *exp) 
            g_free(first);

        }



    bdrv_close(exp->bs);

        g_free(exp);

    }

}



BlockDriverState *nbd_export_get_blockdev(NBDExport *exp)

{

    return exp->bs;

}



void nbd_export_close_all(void)

{

    NBDExport *exp, *next;



    QTAILQ_FOREACH_SAFE(exp, &exports, next, next) {

        nbd_export_close(exp);

    }

}



static int nbd_can_read(void *opaque);

static void nbd_read(void *opaque);
@@ -805,14 +1049,18 @@ out: 
static void nbd_trip(void *opaque)

{

    NBDClient *client = opaque;

    NBDRequest *req = nbd_request_get(client);

    NBDExport *exp = client->exp;

    NBDRequest *req;

    struct nbd_request request;

    struct nbd_reply reply;

    ssize_t ret;



    TRACE("Reading request.");

    if (client->closing) {

        return;

    }



    req = nbd_request_get(client);

    ret = nbd_co_receive_request(req, &request);

    if (ret == -EAGAIN) {

        goto done;
@@ -974,15 +1222,21 @@ NBDClient *nbd_client_new(NBDExport *exp, int csock, 
                          void (*close)(NBDClient *))

{

    NBDClient *client;

    if (nbd_send_negotiate(csock, exp->size, exp->nbdflags) < 0) {

        return NULL;

    }

    client = g_malloc0(sizeof(NBDClient));

    client->refcount = 1;

    client->exp = exp;

    client->sock = csock;

    if (nbd_send_negotiate(client) < 0) {

        g_free(client);

        return NULL;

    }

    client->close = close;

    qemu_co_mutex_init(&client->send_lock);

    qemu_set_fd_handler2(csock, nbd_can_read, nbd_read, NULL, client);



    if (exp) {

        QTAILQ_INSERT_TAIL(&exp->clients, client, next);

        nbd_export_get(exp);

    }

    return client;

}

nbd.h

+14 −1
Original line number Diff line number Diff line
@@ -79,9 +79,22 @@ typedef struct NBDExport NBDExport; 
typedef struct NBDClient NBDClient;



NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset,

                          off_t size, uint32_t nbdflags);

                          off_t size, uint32_t nbdflags,

                          void (*close)(NBDExport *));

void nbd_export_close(NBDExport *exp);

void nbd_export_get(NBDExport *exp);

void nbd_export_put(NBDExport *exp);



BlockDriverState *nbd_export_get_blockdev(NBDExport *exp);



NBDExport *nbd_export_find(const char *name);

void nbd_export_set_name(NBDExport *exp, const char *name);

void nbd_export_close_all(void);



NBDClient *nbd_client_new(NBDExport *exp, int csock,

                          void (*close)(NBDClient *));

void nbd_client_close(NBDClient *client);

void nbd_client_get(NBDClient *client);

void nbd_client_put(NBDClient *client);



#endif

qemu-nbd.c

+28 −8
Original line number Diff line number Diff line
@@ -41,8 +41,8 @@ static NBDExport *exp; 
static int verbose;

static char *srcpath;

static char *sockpath;

static bool sigterm_reported;

static bool nbd_started;

static int persistent = 0;

static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;

static int shared = 1;

static int nb_fds;
@@ -186,7 +186,7 @@ static int find_partition(BlockDriverState *bs, int partition, 


static void termsig_handler(int signum)

{

    sigterm_reported = true;

    state = TERMINATE;

    qemu_notify_event();

}
@@ -269,10 +269,20 @@ static int nbd_can_accept(void *opaque) 
    return nb_fds < shared;

}



static void nbd_export_closed(NBDExport *exp)

{

    assert(state == TERMINATING);

    state = TERMINATED;

}



static void nbd_client_closed(NBDClient *client)

{

    nb_fds--;

    if (nb_fds == 0 && !persistent && state == RUNNING) {

        state = TERMINATE;

    }

    qemu_notify_event();

    nbd_client_put(client);

}



static void nbd_accept(void *opaque)
@@ -282,7 +292,11 @@ static void nbd_accept(void *opaque) 
    socklen_t addr_len = sizeof(addr);



    int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len);

    nbd_started = true;

    if (state >= TERMINATE) {

        close(fd);

        return;

    }



    if (fd >= 0 && nbd_client_new(exp, fd, nbd_client_closed)) {

        nb_fds++;

    }
@@ -329,7 +343,6 @@ int main(int argc, char **argv) 
    int partition = -1;

    int ret;

    int fd;

    int persistent = 0;

    bool seen_cache = false;

#ifdef CONFIG_LINUX_AIO

    bool seen_aio = false;
@@ -546,7 +559,7 @@ int main(int argc, char **argv) 
        }

    }



    exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags);

    exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags, nbd_export_closed);



    if (sockpath) {

        fd = unix_socket_incoming(sockpath);
@@ -581,11 +594,18 @@ int main(int argc, char **argv) 
        err(EXIT_FAILURE, "Could not chdir to root directory");

    }



    state = RUNNING;

    do {

        main_loop_wait(false);

    } while (!sigterm_reported && (persistent || !nbd_started || nb_fds > 0));



        if (state == TERMINATE) {

            state = TERMINATING;

            nbd_export_close(exp);

            nbd_export_put(exp);

            exp = NULL;

        }

    } while (state != TERMINATED);



    bdrv_close(bs);

    if (sockpath) {

        unlink(sockpath);

    }