Commit d24f8023 authored by Stefano Garzarella's avatar Stefano Garzarella Committed by Max Reitz
Browse files

block/rbd: increase dynamically the image size 



RBD APIs don't allow us to write more than the size set with
rbd_create() or rbd_resize().
In order to support growing images (eg. qcow2), we resize the
image before write operations that exceed the current size.

Signed-off-by: default avatarStefano Garzarella <sgarzare@redhat.com>
Message-id: 20190509145927.293369-1-sgarzare@redhat.com
Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
parent 7d0e0240

block/rbd.c

+39 −3
Original line number Diff line number Diff line
@@ -103,6 +103,7 @@ typedef struct BDRVRBDState { 
    rbd_image_t image;

    char *image_name;

    char *snap;

    uint64_t image_size;

} BDRVRBDState;



static int qemu_rbd_connect(rados_t *cluster, rados_ioctx_t *io_ctx,
@@ -778,6 +779,14 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags, 
        goto failed_open;

    }



    r = rbd_get_size(s->image, &s->image_size);

    if (r < 0) {

        error_setg_errno(errp, -r, "error getting image size from %s",

                         s->image_name);

        rbd_close(s->image);

        goto failed_open;

    }



    /* If we are using an rbd snapshot, we must be r/o, otherwise

     * leave as-is */

    if (s->snap != NULL) {
@@ -834,6 +843,22 @@ static void qemu_rbd_close(BlockDriverState *bs) 
    rados_shutdown(s->cluster);

}



/* Resize the RBD image and update the 'image_size' with the current size */

static int qemu_rbd_resize(BlockDriverState *bs, uint64_t size)

{

    BDRVRBDState *s = bs->opaque;

    int r;



    r = rbd_resize(s->image, size);

    if (r < 0) {

        return r;

    }



    s->image_size = size;



    return 0;

}



static const AIOCBInfo rbd_aiocb_info = {

    .aiocb_size = sizeof(RBDAIOCB),

};
@@ -935,13 +960,25 @@ static BlockAIOCB *rbd_start_aio(BlockDriverState *bs, 
    }



    switch (cmd) {

    case RBD_AIO_WRITE:

    case RBD_AIO_WRITE: {

        /*

         * RBD APIs don't allow us to write more than actual size, so in order

         * to support growing images, we resize the image before write

         * operations that exceed the current size.

         */

        if (off + size > s->image_size) {

            r = qemu_rbd_resize(bs, off + size);

            if (r < 0) {

                goto failed_completion;

            }

        }

#ifdef LIBRBD_SUPPORTS_IOVEC

            r = rbd_aio_writev(s->image, qiov->iov, qiov->niov, off, c);

#else

            r = rbd_aio_write(s->image, off, size, rcb->buf, c);

#endif

        break;

    }

    case RBD_AIO_READ:

#ifdef LIBRBD_SUPPORTS_IOVEC

            r = rbd_aio_readv(s->image, qiov->iov, qiov->niov, off, c);
@@ -1052,7 +1089,6 @@ static int coroutine_fn qemu_rbd_co_truncate(BlockDriverState *bs, 
                                             PreallocMode prealloc,

                                             Error **errp)

{

    BDRVRBDState *s = bs->opaque;

    int r;



    if (prealloc != PREALLOC_MODE_OFF) {
@@ -1061,7 +1097,7 @@ static int coroutine_fn qemu_rbd_co_truncate(BlockDriverState *bs, 
        return -ENOTSUP;

    }



    r = rbd_resize(s->image, offset);

    r = qemu_rbd_resize(bs, offset);

    if (r < 0) {

        error_setg_errno(errp, -r, "Failed to resize file");

        return r;