Commit ab01df1f authored by Vladimir Sementsov-Ogievskiy's avatar Vladimir Sementsov-Ogievskiy Committed by Eric Blake
Browse files

nbd/client: refactor nbd_read_eof 



Refactor nbd_read_eof to return 1 on success, 0 on eof, when no
data was read and <0 for other cases, because returned size of
read data is not actually used.

Signed-off-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20170804151440.320927-3-vsementsov@virtuozzo.com>
[eblake: tweak function comments, rebase to test 083 enhancements]
Signed-off-by: default avatarEric Blake <eblake@redhat.com>
parent a0acf3a8

nbd/client.c

+0 −5
Original line number Diff line number Diff line
@@ -925,11 +925,6 @@ ssize_t nbd_receive_reply(QIOChannel *ioc, NBDReply *reply, Error **errp) 
        return ret;

    }



    if (ret != sizeof(buf)) {

        error_setg(errp, "read failed");

        return -EINVAL;

    }



    /* Reply

       [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)

       [ 4 ..  7]    error   (0 == no error)

nbd/nbd-internal.h

+24 −9
Original line number Diff line number Diff line
@@ -77,21 +77,36 @@ 
#define NBD_ESHUTDOWN  108



/* nbd_read_eof

 * Tries to read @size bytes from @ioc. Returns number of bytes actually read.

 * May return a value >= 0 and < size only on EOF, i.e. when iteratively called

 * qio_channel_readv() returns 0. So, there is no need to call nbd_read_eof

 * iteratively.

 * Tries to read @size bytes from @ioc.

 * Returns 1 on success

 *         0 on eof, when no data was read (errp is not set)

 *         negative errno on failure (errp is set)

 */

static inline ssize_t nbd_read_eof(QIOChannel *ioc, void *buffer, size_t size,

static inline int nbd_read_eof(QIOChannel *ioc, void *buffer, size_t size,

                               Error **errp)

{

    struct iovec iov = { .iov_base = buffer, .iov_len = size };

    ssize_t ret;



    /* Sockets are kept in blocking mode in the negotiation phase.  After

     * that, a non-readable socket simply means that another thread stole

     * our request/reply.  Synchronization is done with recv_coroutine, so

     * that this is coroutine-safe.

     */

    return nbd_rwv(ioc, &iov, 1, size, true, errp);



    assert(size);



    ret = nbd_rwv(ioc, &iov, 1, size, true, errp);

    if (ret <= 0) {

        return ret;

    }



    if (ret != size) {

        error_setg(errp, "End of file");

        return -EINVAL;

    }



    return 1;

}



/* nbd_read
@@ -100,9 +115,9 @@ static inline ssize_t nbd_read_eof(QIOChannel *ioc, void *buffer, size_t size, 
static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size,

                           Error **errp)

{

    ssize_t ret = nbd_read_eof(ioc, buffer, size, errp);

    int ret = nbd_read_eof(ioc, buffer, size, errp);



    if (ret >= 0 && ret != size) {

    if (ret == 0) {

        ret = -EINVAL;

        error_setg(errp, "End of file");

    }

tests/qemu-iotests/083.out

+4 −4
Original line number Diff line number Diff line
@@ -69,12 +69,12 @@ read failed: Input/output error 


=== Check disconnect 4 reply ===



read failed

End of file

read failed: Input/output error



=== Check disconnect 8 reply ===



read failed

End of file

read failed: Input/output error



=== Check disconnect before data ===
@@ -180,12 +180,12 @@ read failed: Input/output error 


=== Check disconnect 4 reply ===



read failed

End of file

read failed: Input/output error



=== Check disconnect 8 reply ===



read failed

End of file

read failed: Input/output error



=== Check disconnect before data ===