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Re: [Qemu-block] [PATCH v2 1/2] block/nfs: Introduce runtime_opts in NFS
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From: |
Kevin Wolf |
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Subject: |
Re: [Qemu-block] [PATCH v2 1/2] block/nfs: Introduce runtime_opts in NFS |
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Date: |
Tue, 25 Oct 2016 16:02:48 +0200 |
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User-agent: |
Mutt/1.5.21 (2010-09-15) |
Peter, there is a question for you hidden somewhere below.
Am 24.10.2016 um 21:27 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.
>
> Signed-off-by: Ashijeet Acharya <address@hidden>
> ---
> block/nfs.c | 348
> +++++++++++++++++++++++++++++++++++++++++++-----------------
> 1 file changed, 253 insertions(+), 95 deletions(-)
>
> diff --git a/block/nfs.c b/block/nfs.c
> index 8602a44..666ccf2 100644
> --- a/block/nfs.c
> +++ b/block/nfs.c
> @@ -35,8 +35,12 @@
> #include "qemu/uri.h"
> #include "qemu/cutils.h"
> #include "sysemu/sysemu.h"
> +#include "qapi/qmp/qdict.h"
> +#include "qapi/qmp/qint.h"
> +#include "qapi/qmp/qstring.h"
> #include <nfsc/libnfs.h>
>
> +
> #define QEMU_NFS_MAX_READAHEAD_SIZE 1048576
> #define QEMU_NFS_MAX_PAGECACHE_SIZE (8388608 / NFS_BLKSIZE)
> #define QEMU_NFS_MAX_DEBUG_LEVEL 2
> @@ -61,6 +65,118 @@ typedef struct NFSRPC {
> NFSClient *client;
> } NFSRPC;
>
> +static int nfs_parse_uri(const char *filename, QDict *options, Error **errp)
> +{
> + URI *uri = NULL;
> + QueryParams *qp = NULL;
> + int ret = 0, i;
> +
> + uri = uri_parse(filename);
> + if (!uri) {
> + error_setg(errp, "Invalid URI specified");
> + ret = -EINVAL;
> + goto out;
> + }
> + if (strcmp(uri->scheme, "nfs") != 0) {
> + error_setg(errp, "URI scheme must be 'nfs'");
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + if (!uri->server) {
> + error_setg(errp, "missing hostname in URI");
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + if (!uri->path) {
> + error_setg(errp, "missing file path in URI");
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + qp = query_params_parse(uri->query);
> + if (!qp) {
> + error_setg(errp, "could not parse query parameters");
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + qdict_put(options, "host", qstring_from_str(uri->server));
> +
> + qdict_put(options, "path", qstring_from_str(uri->path));
Just style, but why the empty line between both qdict_put() calls?
> +
> + for (i = 0; i < qp->n; i++) {
> + if (!qp->p[i].value) {
> + error_setg(errp, "Value for NFS parameter expected: %s",
> + qp->p[i].name);
> + goto out;
You need to set ret = -EINVAL here.
> + }
> + if (parse_uint_full(qp->p[i].value, NULL, 0)) {
> + error_setg(errp, "Illegal value for NFS parameter: %s",
> + qp->p[i].name);
> + goto out;
And here.
> + }
> + if (!strcmp(qp->p[i].name, "uid")) {
> + qdict_put(options, "uid",
> + qstring_from_str(qp->p[i].value));
> + } else if (!strcmp(qp->p[i].name, "gid")) {
> + qdict_put(options, "gid",
> + qstring_from_str(qp->p[i].value));
> + } else if (!strcmp(qp->p[i].name, "tcp-syncnt")) {
> + qdict_put(options, "tcp-syncnt",
> + qstring_from_str(qp->p[i].value));
> + } else if (!strcmp(qp->p[i].name, "readahead")) {
> + qdict_put(options, "readahead",
> + qstring_from_str(qp->p[i].value));
> + } else if (!strcmp(qp->p[i].name, "pagecache")) {
> + qdict_put(options, "pagecache",
> + qstring_from_str(qp->p[i].value));
> + } else if (!strcmp(qp->p[i].name, "debug")) {
> + qdict_put(options, "debug",
> + qstring_from_str(qp->p[i].value));
> + } else {
> + error_setg(errp, "Unknown NFS parameter name: %s",
> + qp->p[i].name);
> + goto out;
And here.
If you prefer, you can set ret = -EINVAL at the top of the function and
do a ret = 0 only right before out:
> + }
> + }
> +out:
> + if (qp) {
> + query_params_free(qp);
> + }
> + if (uri) {
> + uri_free(uri);
> + }
> + return ret;
> +}
> +
> +static void nfs_parse_filename(const char *filename, QDict *options,
> + Error **errp)
> +{
> + int ret = 0;
> +
> + if (qdict_haskey(options, "host") ||
> + qdict_haskey(options, "path") ||
> + qdict_haskey(options, "uid") ||
> + qdict_haskey(options, "gid") ||
> + qdict_haskey(options, "tcp-syncnt") ||
> + qdict_haskey(options, "readahead") ||
> + qdict_haskey(options, "pagecache") ||
> + qdict_haskey(options, "debug")) {
> + error_setg(errp, "host/path/uid/gid/tcp-syncnt/readahead/pagecache"
> + "/debug and a filename may not be used at the same"
> + " time");
> + return;
> + }
> +
> + ret = nfs_parse_uri(filename, options, errp);
> + if (ret < 0) {
> + error_setg(errp, "No valid URL specified");
errp has already been set by nfs_parse_uri(), you must not set it a
second time. Otherwise, this is what you get:
$ x86_64-softmmu/qemu-system-x86_64 -drive file=nfs://foo
qemu-system-x86_64: util/error.c:57: error_setv: Assertion `*errp == ((void
*)0)' failed.
Aborted
> + }
> + return;
> +}
> +
> static void nfs_process_read(void *arg);
> static void nfs_process_write(void *arg);
>
> @@ -228,15 +344,49 @@ 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",
> + },
> + {
> + .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 +429,40 @@ static void nfs_file_close(BlockDriverState *bs)
> nfs_client_close(client);
> }
>
> -static int64_t nfs_client_open(NFSClient *client, const char *filename,
> +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;
> + const char *host, *path;
> + unsigned long long val;
>
> - uri = uri_parse(filename);
> - if (!uri) {
> - error_setg(errp, "Invalid URL specified");
> - goto fail;
> + 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;
> }
> - if (!uri->server) {
> - error_setg(errp, "Invalid URL specified");
> - goto fail;
> +
> + host = qemu_opt_get(opts, "host");
> + if (!host) {
> + ret = -EINVAL;
> + error_setg(errp, "No hostname was specified");
> + goto out;
> }
> - strp = strrchr(uri->path, '/');
> +
> + path = qemu_opt_get(opts, "path");
> + if (!path) {
> + ret = -EINVAL;
> + error_setg(errp, "No path was specified");
> + goto out;
> + }
> +
> + strp = strrchr(path, '/');
> if (strp == NULL) {
> error_setg(errp, "Invalid URL specified");
> goto fail;
This is inconsistent. Either all error paths before initialising the
context should 'goto fail' anyway (and I'd prefer this), or they should
all 'goto out'. I don't like mixing both.
> @@ -311,79 +476,77 @@ static int64_t nfs_client_open(NFSClient *client, const
> char *filename,
> 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")) {
> + nfs_set_uid(client->context,
> + qemu_opt_get_number(opts, "uid", getuid()));
Isn't the getuid() useless here? We already check that an "uid" option
is passed (and I think doing that is correct), so the default is never
used. We could just as well pass 0 as the default.
> + }
> +
> + if (qemu_opt_get(opts, "gid")) {
> + nfs_set_gid(client->context,
> + qemu_opt_get_number(opts, "gid", getgid()));
Here, too.
> + }
> +
> + if (qemu_opt_get(opts, "tcp-syncnt")) {
> + nfs_set_tcp_syncnt(client->context,
> + qemu_opt_get_number(opts, "tcp-syncnt", 0));
> + }
> +
> +#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;
> + val = qemu_opt_get_number(opts, "readahead", 0);
> + 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;
> }
> - 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, val);
> #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;
> + nfs_set_pagecache_ttl(client->context, 0);
We have a functional change here. I'm not completely sure yet whether
you're fixing a bug here or you're just turning one bug into a different
bug, but the old code doesn't look right anyway.
If LIBNFS_FEATURE_READAHEAD was defined, but LIBNFS_FEATURE_PAGECACHE
wasn't, the nfs_set_pagecache_ttl() would end up in the "tcp-syncnt"
option handling, which is probably completely wrong.
I suspect that commit d99b26c4 added the second call accidentally
(intended just a copy and paste of the #ifdef line?) and this line
should simply be dropped.
Peter?
> + 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;
> + }
> + val = qemu_opt_get_number(opts, "pagecache", 0);
> + 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;
> + }
> #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")) {
> + val = qemu_opt_get_number(opts, "debug", 0);
> + /* 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
>
> - ret = nfs_mount(client->context, uri->server, uri->path);
> + ret = nfs_mount(client->context, host, path);
> if (ret < 0) {
> error_setg(errp, "Failed to mount nfs share: %s",
> nfs_get_error(client->context));
> @@ -417,13 +580,11 @@ 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 +593,17 @@ 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 +625,7 @@ 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 +633,14 @@ 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) {
> + error_setg(errp, "No valid URL specified");
Same thing as above, you can't set errp twice.
> + goto out;
> + }
> +
> + ret = nfs_client_open(client, options, O_CREAT, errp, 0);
> if (ret < 0) {
> goto out;
> }
> @@ -578,7 +736,7 @@ static BlockDriver bdrv_nfs = {
> .protocol_name = "nfs",
>
> .instance_size = sizeof(NFSClient),
> - .bdrv_needs_filename = true,
> + .bdrv_parse_filename = nfs_parse_filename,
> .create_opts = &nfs_create_opts,
>
> .bdrv_has_zero_init = nfs_has_zero_init,
Kevin