Re: [Qemu-devel] [PATCH 1/2] virtio-9p: Add support for 9p migration.

[Benoît Canet]

The Friday 26 Sep 2014 à 18:19:56 (+0300), Boris Sukholitko wrote :


> This patch is a rebase of Aneesh Kumar's and Benoit Canet's previous
> work.
> 
> Signed-off-by: Boris Sukholitko <address@hidden>

If Aneesh and me worked on this you should also keep our signed-off in addition
of yours.

Best regards

Benoît

> ---
>  hw/9pfs/virtio-9p-device.c | 152 
> +++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 152 insertions(+)
> 
> diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
> index 2572747..078ad39 100644
> --- a/hw/9pfs/virtio-9p-device.c
> +++ b/hw/9pfs/virtio-9p-device.c
> @@ -21,6 +21,149 @@
>  #include "virtio-9p-coth.h"
>  #include "hw/virtio/virtio-access.h"
>  
> +static void virtio_9p_save_path(QEMUFile *f, V9fsPath *path)
> +{
> +    qemu_put_be16(f, path->size);
> +    qemu_put_buffer(f, (const uint8_t *) path->data, path->size);
> +}
> +
> +static void virtio_9p_save_string(QEMUFile *f, V9fsString *s)
> +{
> +    qemu_put_be16(f, s->size);
> +    qemu_put_buffer(f, (const uint8_t *) s->data, s->size);
> +}
> +
> +static void virtio_9p_save_xattr(QEMUFile *f, V9fsXattr *xattr)
> +{
> +    qemu_put_be64(f, xattr->copied_len);
> +    qemu_put_be64(f, xattr->len);
> +    qemu_put_buffer(f, (const uint8_t *) xattr->value, xattr->len);
> +    virtio_9p_save_string(f, &xattr->name);
> +    qemu_put_be32(f, xattr->flags);
> +}
> +
> +static void virtio_9p_save_fid(QEMUFile *f, V9fsFidState *fid)
> +{
> +    /* First close the fid and mark it for reopen if migration fail */
> +    if (fid->fid_type == P9_FID_FILE) {
> +        close(fid->fs.fd);
> +        fid->fs.fd = -1;
> +    } else if (fid->fid_type == P9_FID_DIR) {
> +        closedir(fid->fs.dir);
> +        fid->fs.dir = NULL;
> +    }
> +
> +    qemu_put_be32(f, fid->fid_type);
> +    if (fid->fid_type == P9_FID_XATTR) {
> +        /* we don't save fs_reclaim */
> +        virtio_9p_save_xattr(f, &fid->fs.xattr);
> +    }
> +    qemu_put_be32(f, fid->fid);
> +    virtio_9p_save_path(f, &fid->path);
> +    qemu_put_be32(f, fid->flags);
> +    qemu_put_be32(f, fid->open_flags);
> +    qemu_put_be32(f, fid->uid);
> +    qemu_put_be32(f, fid->ref);
> +    qemu_put_be32(f, fid->clunked);
> +}
> +
> +static void virtio_9p_save(QEMUFile *f, void *opaque)
> +{
> +    int fidcount = 0;
> +    V9fsState *s = opaque;
> +    V9fsFidState *fid;
> +
> +    virtio_save(VIRTIO_DEVICE(s), f);
> +
> +    for (fid = s->fid_list; fid; fid = fid->next) {
> +        fidcount++;
> +    }
> +    /* Write the total number of fid structure */
> +    qemu_put_be32(f, fidcount);
> +
> +    for (fid = s->fid_list; fid; fid = fid->next) {
> +        virtio_9p_save_fid(f, fid);
> +    }
> +
> +    qemu_put_be32(f, s->proto_version);
> +    qemu_put_be32(f, s->msize);
> +}
> +
> +static void virtio_9p_load_path(QEMUFile *f, V9fsPath *path)
> +{
> +    path->size = qemu_get_be16(f);
> +    path->data = g_malloc0(path->size);
> +    qemu_get_buffer(f, (uint8_t *) path->data, path->size);
> +}
> +
> +static void virtio_9p_load_string(QEMUFile *f, V9fsString *s)
> +{
> +    s->size = qemu_get_be16(f);
> +    s->data = g_malloc0(s->size);
> +    qemu_get_buffer(f, (uint8_t *) s->data, s->size);
> +}
> +
> +static void virtio_9p_load_xattr(QEMUFile *f, V9fsXattr *xattr)
> +{
> +    xattr->copied_len = qemu_get_be64(f);
> +    xattr->len = qemu_get_be64(f);
> +    qemu_get_buffer(f, (uint8_t *) xattr->value, xattr->len);
> +    virtio_9p_load_string(f, &xattr->name);
> +    xattr->flags = qemu_get_be32(f);
> +}
> +
> +static V9fsFidState *virtio_9p_load_fid(QEMUFile *f)
> +{
> +    V9fsFidState *fid;
> +    fid = g_new0(V9fsFidState, 1);
> +
> +    fid->fid_type    = qemu_get_be32(f);
> +    if (fid->fid_type == P9_FID_XATTR) {
> +        virtio_9p_load_xattr(f, &fid->fs.xattr);
> +    }
> +    fid->fid         = qemu_get_be32(f);
> +    virtio_9p_load_path(f, &fid->path);
> +    fid->flags       = qemu_get_be32(f);
> +    fid->open_flags  = qemu_get_be32(f);
> +    fid->uid         = qemu_get_be32(f);
> +    fid->ref         = qemu_get_be32(f);
> +    fid->clunked     = qemu_get_be32(f);
> +
> +    /* If it's a file fid mark the file descriptors as closed.
> +     * DIR is null thanks to g_new0.
> +     * When doing get_fid v9fs_reopen_fid will reopen the file or the 
> directory.
> +     */
> +    if (fid->fid_type == P9_FID_FILE) {
> +        fid->fs.fd = -1;
> +    }
> +    return fid;
> +}
> +
> +static int virtio_9p_load(QEMUFile *f, void *opaque, int version_id)
> +{
> +    int fidcount;
> +    V9fsState *s = opaque;
> +    V9fsFidState **fid;
> +
> +    if (version_id != 2) {
> +        return -EINVAL;
> +    }
> +    virtio_load(VIRTIO_DEVICE(s), f, version_id);
> +    fidcount = qemu_get_be32(f);
> +
> +    fid = &s->fid_list;
> +    while (fidcount) {
> +        *fid = virtio_9p_load_fid(f);
> +        fid = &((*fid)->next);
> +        fidcount--;
> +    }
> +
> +    s->proto_version  = qemu_get_be32(f);
> +    s->msize          = qemu_get_be32(f);
> +
> +    return 0;
> +}
> +
>  static uint32_t virtio_9p_get_features(VirtIODevice *vdev, uint32_t features)
>  {
>      features |= 1 << VIRTIO_9P_MOUNT_TAG;
> @@ -50,6 +193,7 @@ static void virtio_9p_device_realize(DeviceState *dev, 
> Error **errp)
>      struct stat stat;
>      FsDriverEntry *fse;
>      V9fsPath path;
> +    static int virtio_9p_id;
>  
>      virtio_init(vdev, "virtio-9p", VIRTIO_ID_9P,
>                  sizeof(struct virtio_9p_config) + MAX_TAG_LEN);
> @@ -98,6 +242,14 @@ static void virtio_9p_device_realize(DeviceState *dev, 
> Error **errp)
>      s->ops = fse->ops;
>      s->config_size = sizeof(struct virtio_9p_config) + len;
>      s->fid_list = NULL;
> +
> +    /* Original patch says that instance id must be derived of tag
> +     * name. Hash functions do have collisions so why would it be better
> +     * than an increment ?
> +     */
> +    register_savevm(dev, "virtio-9p", virtio_9p_id++, 2,
> +                    virtio_9p_save, virtio_9p_load, s);
> +
>      qemu_co_rwlock_init(&s->rename_lock);
>  
>      if (s->ops->init(&s->ctx) < 0) {
> -- 
> 2.0.2
> 
>