Re: [Qemu-devel] [PATCH v4 1/2] block/nfs: Introduce runtime_opts in NFS

[Kevin Wolf <kwolf@redhat.com>]

Am 28.10.2016 um 14:47 hat Ashijeet Acharya geschrieben:
> Make NFS block driver use various fine grained runtime_opts.
> Set .bdrv_parse_filename() to nfs_parse_filename() and introduce two
> new functions nfs_parse_filename() and nfs_parse_uri() to help parsing
> the URI.
> Add a new option "server" which then accepts a new struct NFSServer.
> "host" is supported as a legacy option and is mapped to its NFSServer
> representation.
> 
> Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com>

This patch doesn't apply any more and must be rebased. And even when you
make it technically apply, it still doesn't compile:

block/nfs.c: In function 'nfs_config':
block/nfs.c:477:5: error: passing argument 2 of 'qdict_crumple' makes pointer from integer without a cast [-Werror]
     crumpled_addr = qdict_crumple(addr, true, errp);

This is because qdict_crumple() as it ended up in master has only two
arguments.

> @@ -228,15 +354,49 @@ static int coroutine_fn nfs_co_flush(BlockDriverState *bs)
>      return task.ret;
>  }
>  
> -/* TODO Convert to fine grained options */
>  static QemuOptsList runtime_opts = {
>      .name = "nfs",
>      .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
>      .desc = {
>          {
> -            .name = "filename",
> +            .name = "host",
> +            .type = QEMU_OPT_STRING,
> +            .help = "Host to connect to",
> +        },

This "legacy option" as the commit message calls it, is introduced only
now. Maybe we should completely leave it out. It could make some sense
as a convenience feature, but we can still add that later, and the
existing convenience syntax is the URI, so maybe we don't need a second
one.

> +        {
> +            .name = "path",
>              .type = QEMU_OPT_STRING,
> -            .help = "URL to the NFS file",
> +            .help = "Path of the image on the host",
> +        },
> +        {
> +            .name = "uid",
> +            .type = QEMU_OPT_NUMBER,
> +            .help = "UID value to use when talking to the server",
> +        },
> +        {
> +            .name = "gid",
> +            .type = QEMU_OPT_NUMBER,
> +            .help = "GID value to use when talking to the server",
> +        },
> +        {
> +            .name = "tcp-syncnt",
> +            .type = QEMU_OPT_NUMBER,
> +            .help = "Number of SYNs to send during the session establish",
> +        },
> +        {
> +            .name = "readahead",
> +            .type = QEMU_OPT_NUMBER,
> +            .help = "Set the readahead size in bytes",
> +        },
> +        {
> +            .name = "pagecache",
> +            .type = QEMU_OPT_NUMBER,
> +            .help = "Set the pagecache size in bytes",
> +        },
> +        {
> +            .name = "debug",
> +            .type = QEMU_OPT_NUMBER,
> +            .help = "Set the NFS debug level (max 2)",
>          },
>          { /* end of list */ }
>      },
> @@ -279,25 +439,94 @@ static void nfs_file_close(BlockDriverState *bs)
>      nfs_client_close(client);
>  }
>  
> -static int64_t nfs_client_open(NFSClient *client, const char *filename,
> +static bool nfs_process_legacy_socket_options(QDict *output_opts,
> +                                              QemuOpts *legacy_opts,
> +                                              Error **errp)
> +{
> +    const char *host = qemu_opt_get(legacy_opts, "host");
> +    const char *inet = qemu_opt_get(legacy_opts, "inet");

"inet" is not an option in runtime_opts, so this is always NULL.

> +    if (!host && inet) {
> +        error_setg(errp, "No hostname was specified");
> +        return false;
> +    }
> +    if (host && !inet) {
> +        error_setg(errp, "No transportation type was specified");
> +        return false;
> +    }
> +
> +    if (host) {
> +        qdict_put(output_opts, "server.host", qstring_from_str(host));
> +        qdict_put(output_opts, "server.type", qstring_from_str(inet));

If you want this to be a convenience feature, you might want to set it
to qstring_from_str("inet"), i.e. use the literal string "inet" like in
nfs_parse_uri().

But probably the best is to leave out this function completely and to
support only explicit "server.type" and "server.host".

> +    }
> +
> +    return true;
> +}
> +
> +static NFSServer *nfs_config(QDict *options, Error **errp)
> +{
> +    NFSServer *inet = NULL;
> +    QDict *addr = NULL;
> +    QObject *crumpled_addr = NULL;
> +    Visitor *iv = NULL;
> +    Error *local_error = NULL;
> +
> +    qdict_extract_subqdict(options, &addr, "server.");
> +    if (!qdict_size(addr)) {
> +        error_setg(errp, "NFS server address missing");
> +        goto out;
> +    }
> +
> +    crumpled_addr = qdict_crumple(addr, true, errp);
> +    if (!crumpled_addr) {
> +        goto out;
> +    }
> +
> +    iv = qobject_input_visitor_new(crumpled_addr, true);
> +    visit_type_NFSServer(iv, NULL, &inet, &local_error);
> +    if (local_error) {
> +        error_propagate(errp, local_error);
> +        goto out;
> +    }
> +
> +out:
> +    QDECREF(addr);
> +    qobject_decref(crumpled_addr);
> +    visit_free(iv);
> +    return inet;
> +}
> +
> +
> +static int64_t nfs_client_open(NFSClient *client, QDict *options,
>                                 int flags, Error **errp, int open_flags)
>  {
> -    int ret = -EINVAL, i;
> +    int ret = -EINVAL;
> +    QemuOpts *opts = NULL;
> +    Error *local_err = NULL;
>      struct stat st;
> -    URI *uri;
> -    QueryParams *qp = NULL;
>      char *file = NULL, *strp = NULL;
>  
> -    uri = uri_parse(filename);
> -    if (!uri) {
> -        error_setg(errp, "Invalid URL specified");
> +    opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
> +    qemu_opts_absorb_qdict(opts, options, &local_err);
> +    if (local_err) {
> +        error_propagate(errp, local_err);
> +        ret = -EINVAL;
>          goto fail;
>      }
> -    if (!uri->server) {
> -        error_setg(errp, "Invalid URL specified");
> +
> +    if (!nfs_process_legacy_socket_options(options, opts, errp)) {
> +        ret = -EINVAL;
>          goto fail;
>      }
> -    strp = strrchr(uri->path, '/');
> +
> +    client->path = g_strdup(qemu_opt_get(opts, "path"));
> +    if (!client->path) {
> +        ret = -EINVAL;
> +        error_setg(errp, "No path was specified");
> +        goto fail;
> +    }
> +
> +    strp = strrchr(client->path, '/');
>      if (strp == NULL) {
>          error_setg(errp, "Invalid URL specified");
>          goto fail;
> @@ -305,85 +534,89 @@ static int64_t nfs_client_open(NFSClient *client, const char *filename,
>      file = g_strdup(strp);
>      *strp = 0;
>  
> +    /* Pop the config into our state object, Exit if invalid */
> +    client->inet = nfs_config(options, errp);

This isn't an InetSocketAddress, so maybe client->server rather than
client->inet.

> +    if (!client->inet) {
> +        ret = -EINVAL;
> +        goto fail;
> +    }
> +
>      client->context = nfs_init_context();
>      if (client->context == NULL) {
>          error_setg(errp, "Failed to init NFS context");
>          goto fail;
>      }
>  
> -    qp = query_params_parse(uri->query);
> -    for (i = 0; i < qp->n; i++) {
> -        unsigned long long val;
> -        if (!qp->p[i].value) {
> -            error_setg(errp, "Value for NFS parameter expected: %s",
> -                       qp->p[i].name);
> +    if (qemu_opt_get(opts, "uid")) {
> +        client->uid = qemu_opt_get_number(opts, "uid", 0);
> +        nfs_set_uid(client->context, client->uid);
> +    }
> +
> +    if (qemu_opt_get(opts, "gid")) {
> +        client->gid = qemu_opt_get_number(opts, "gid", 0);
> +        nfs_set_gid(client->context, client->gid);
> +    }
> +
> +    if (qemu_opt_get(opts, "tcp-syncnt")) {
> +        client->tcp_syncnt = qemu_opt_get_number(opts, "tcp-syncnt", 0);
> +        nfs_set_tcp_syncnt(client->context, client->tcp_syncnt);
> +    }
> +
> +#ifdef LIBNFS_FEATURE_READAHEAD
> +    if (qemu_opt_get(opts, "readahead")) {
> +        if (open_flags & BDRV_O_NOCACHE) {
> +            error_setg(errp, "Cannot enable NFS readahead "
> +                             "if cache.direct = on");
>              goto fail;
>          }
> -        if (parse_uint_full(qp->p[i].value, &val, 0)) {
> -            error_setg(errp, "Illegal value for NFS parameter: %s",
> -                       qp->p[i].name);
> -            goto fail;
> +        client->readahead = qemu_opt_get_number(opts, "readahead", 0);
> +        if (client->readahead > QEMU_NFS_MAX_READAHEAD_SIZE) {
> +            error_report("NFS Warning: Truncating NFS readahead "
> +                         "size to %d", QEMU_NFS_MAX_READAHEAD_SIZE);
> +            client->readahead = QEMU_NFS_MAX_READAHEAD_SIZE;
>          }
> -        if (!strcmp(qp->p[i].name, "uid")) {
> -            nfs_set_uid(client->context, val);
> -        } else if (!strcmp(qp->p[i].name, "gid")) {
> -            nfs_set_gid(client->context, val);
> -        } else if (!strcmp(qp->p[i].name, "tcp-syncnt")) {
> -            nfs_set_tcp_syncnt(client->context, val);
> -#ifdef LIBNFS_FEATURE_READAHEAD
> -        } else if (!strcmp(qp->p[i].name, "readahead")) {
> -            if (open_flags & BDRV_O_NOCACHE) {
> -                error_setg(errp, "Cannot enable NFS readahead "
> -                                 "if cache.direct = on");
> -                goto fail;
> -            }
> -            if (val > QEMU_NFS_MAX_READAHEAD_SIZE) {
> -                error_report("NFS Warning: Truncating NFS readahead"
> -                             " size to %d", QEMU_NFS_MAX_READAHEAD_SIZE);
> -                val = QEMU_NFS_MAX_READAHEAD_SIZE;
> -            }
> -            nfs_set_readahead(client->context, val);
> +        nfs_set_readahead(client->context, client->readahead);
>  #ifdef LIBNFS_FEATURE_PAGECACHE
> -            nfs_set_pagecache_ttl(client->context, 0);
> +        nfs_set_pagecache_ttl(client->context, 0);
>  #endif
> -            client->cache_used = true;
> +        client->cache_used = true;
> +    }
>  #endif
> +
>  #ifdef LIBNFS_FEATURE_PAGECACHE
> -            nfs_set_pagecache_ttl(client->context, 0);
> -        } else if (!strcmp(qp->p[i].name, "pagecache")) {
> -            if (open_flags & BDRV_O_NOCACHE) {
> -                error_setg(errp, "Cannot enable NFS pagecache "
> -                                 "if cache.direct = on");
> -                goto fail;
> -            }
> -            if (val > QEMU_NFS_MAX_PAGECACHE_SIZE) {
> -                error_report("NFS Warning: Truncating NFS pagecache"
> -                             " size to %d pages", QEMU_NFS_MAX_PAGECACHE_SIZE);
> -                val = QEMU_NFS_MAX_PAGECACHE_SIZE;
> -            }
> -            nfs_set_pagecache(client->context, val);
> -            nfs_set_pagecache_ttl(client->context, 0);
> -            client->cache_used = true;
> +    if (qemu_opt_get(opts, "pagecache")) {
> +        if (open_flags & BDRV_O_NOCACHE) {
> +            error_setg(errp, "Cannot enable NFS pagecache "
> +                             "if cache.direct = on");
> +            goto fail;
> +        }
> +        client->pagecache = qemu_opt_get_number(opts, "pagecache", 0);
> +        if (client->pagecache > QEMU_NFS_MAX_PAGECACHE_SIZE) {
> +            error_report("NFS Warning: Truncating NFS pagecache "
> +                         "size to %d pages", QEMU_NFS_MAX_PAGECACHE_SIZE);
> +            client->pagecache = QEMU_NFS_MAX_PAGECACHE_SIZE;
> +        }
> +        nfs_set_pagecache(client->context, client->pagecache);
> +        nfs_set_pagecache_ttl(client->context, 0);
> +        client->cache_used = true;
> +    }
>  #endif
> +
>  #ifdef LIBNFS_FEATURE_DEBUG
> -        } else if (!strcmp(qp->p[i].name, "debug")) {
> -            /* limit the maximum debug level to avoid potential flooding
> -             * of our log files. */
> -            if (val > QEMU_NFS_MAX_DEBUG_LEVEL) {
> -                error_report("NFS Warning: Limiting NFS debug level"
> -                             " to %d", QEMU_NFS_MAX_DEBUG_LEVEL);
> -                val = QEMU_NFS_MAX_DEBUG_LEVEL;
> -            }
> -            nfs_set_debug(client->context, val);
> -#endif
> -        } else {
> -            error_setg(errp, "Unknown NFS parameter name: %s",
> -                       qp->p[i].name);
> -            goto fail;
> +    if (qemu_opt_get(opts, "debug")) {
> +        client->debug = qemu_opt_get_number(opts, "debug", 0);
> +        /* limit the maximum debug level to avoid potential flooding
> +         * of our log files. */
> +        if (client->debug > QEMU_NFS_MAX_DEBUG_LEVEL) {
> +            error_report("NFS Warning: Limiting NFS debug level "
> +                         "to %d", QEMU_NFS_MAX_DEBUG_LEVEL);
> +            client->debug = QEMU_NFS_MAX_DEBUG_LEVEL;
>          }
> +        nfs_set_debug(client->context, client->debug);
>      }
> +#endif
>  
> -    ret = nfs_mount(client->context, uri->server, uri->path);
> +    ret = nfs_mount(client->context, client->inet->host, client->path);
>      if (ret < 0) {
>          error_setg(errp, "Failed to mount nfs share: %s",
>                     nfs_get_error(client->context));
> @@ -417,13 +650,11 @@ static int64_t nfs_client_open(NFSClient *client, const char *filename,
>      client->st_blocks = st.st_blocks;
>      client->has_zero_init = S_ISREG(st.st_mode);
>      goto out;
> +
>  fail:
>      nfs_client_close(client);
>  out:
> -    if (qp) {
> -        query_params_free(qp);
> -    }
> -    uri_free(uri);
> +    qemu_opts_del(opts);
>      g_free(file);
>      return ret;
>  }
> @@ -432,28 +663,17 @@ static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags,
>                           Error **errp) {
>      NFSClient *client = bs->opaque;
>      int64_t ret;
> -    QemuOpts *opts;
> -    Error *local_err = NULL;
>  
>      client->aio_context = bdrv_get_aio_context(bs);
>  
> -    opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
> -    qemu_opts_absorb_qdict(opts, options, &local_err);
> -    if (local_err) {
> -        error_propagate(errp, local_err);
> -        ret = -EINVAL;
> -        goto out;
> -    }
> -    ret = nfs_client_open(client, qemu_opt_get(opts, "filename"),
> +    ret = nfs_client_open(client, options,
>                            (flags & BDRV_O_RDWR) ? O_RDWR : O_RDONLY,
>                            errp, bs->open_flags);
>      if (ret < 0) {
> -        goto out;
> +        return ret;
>      }
>      bs->total_sectors = ret;
>      ret = 0;
> -out:
> -    qemu_opts_del(opts);
>      return ret;
>  }
>  
> @@ -475,6 +695,7 @@ static int nfs_file_create(const char *url, QemuOpts *opts, Error **errp)
>      int ret = 0;
>      int64_t total_size = 0;
>      NFSClient *client = g_new0(NFSClient, 1);
> +    QDict *options = NULL;
>  
>      client->aio_context = qemu_get_aio_context();
>  
> @@ -482,7 +703,13 @@ static int nfs_file_create(const char *url, QemuOpts *opts, Error **errp)
>      total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
>                            BDRV_SECTOR_SIZE);
>  
> -    ret = nfs_client_open(client, url, O_CREAT, errp, 0);
> +    options = qdict_new();
> +    ret = nfs_parse_uri(url, options, errp);
> +    if (ret < 0) {
> +        goto out;
> +    }
> +
> +    ret = nfs_client_open(client, options, O_CREAT, errp, 0);
>      if (ret < 0) {
>          goto out;
>      }
> @@ -564,6 +791,49 @@ static int nfs_reopen_prepare(BDRVReopenState *state,
>      return 0;
>  }
>  
> +static void nfs_refresh_filename(BlockDriverState *bs, QDict *options)
> +{
> +    NFSClient *client = bs->opaque;
> +    QDict *opts = qdict_new();
> +    QObject *inet_qdict;
> +    Visitor *ov;
> +
> +    qdict_put_obj(opts, "driver", QOBJECT(qstring_from_str("nfs")));

qdict_put(opts, "driver", qstring_from_str("nfs"));

Same for the other occurrences.

> +    ov = qobject_output_visitor_new(&inet_qdict);
> +    visit_type_NFSServer(ov, NULL, &client->inet, &error_abort);
> +    visit_complete(ov, &client->inet);
> +    assert(qobject_type(inet_qdict) == QTYPE_QDICT);
> +
> +    qdict_put_obj(opts, "server", inet_qdict);
> +    qdict_put_obj(opts, "path", QOBJECT(qstring_from_str(client->path)));
> +
> +    if (client->uid) {
> +        qdict_put_obj(opts, "uid", QOBJECT(qint_from_int(client->uid)));
> +    }
> +    if (client->gid) {
> +        qdict_put_obj(opts, "gid", QOBJECT(qint_from_int(client->gid)));
> +    }
> +    if (client->tcp_syncnt) {
> +        qdict_put_obj(opts, "tcp-syncnt",
> +                      QOBJECT(qint_from_int(client->tcp_syncnt)));
> +    }
> +    if (client->readahead) {
> +        qdict_put_obj(opts, "readahead",
> +                      QOBJECT(qint_from_int(client->readahead)));
> +    }
> +    if (client->pagecache) {
> +        qdict_put_obj(opts, "pagecache",
> +                      QOBJECT(qint_from_int(client->pagecache)));
> +    }
> +    if (client->debug) {
> +        qdict_put_obj(opts, "debug", QOBJECT(qint_from_int(client->debug)));
> +    }
> +
> +    qdict_flatten(opts);
> +    bs->full_open_options = opts;
> +}

This function needs to set bs->exact_filename if the options can be
represented in a URI (like in NBD).


And actually, qemu-iotests 104 fails earlier so that the effect of the
missing bs->exact_filename can't be seen:

+qemu-img: qapi/qobject-output-visitor.c:206: qobject_output_complete: Assertion `opaque == qov->result' failed.
+./common.config: line 119:  2093 Aborted                 (core dumped) ( exec "$QEMU_IMG_PROG" $QEMU_IMG_OPTIONS "$@" )

Kevin