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curl: implement .bdrv_detach/attach_aio_context()
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The curl block driver uses fd handlers, timers, and BHs.  The fd
handlers and timers are managed on behalf of libcurl, which controls
them using callback functions that the block driver implements.

The simplest way to implement .bdrv_detach/attach_aio_context() is to
clean up libcurl in the old event loop and initialize it again in the
new event loop.  We do not need to keep track of anything since there
are no pending requests when the AioContext is changed.

Also make sure to use aio_set_fd_handler() instead of
qemu_aio_set_fd_handler() and aio_bh_new() instead of qemu_bh_new() so
the current AioContext is passed in.

Cc: Alexander Graf <agraf@suse.de>
Cc: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
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@stefanhaRH
stefanhaRH committed Jun 4, 2014
1 parent 9d94020 commit 63f0f45
Showing 1 changed file with 115 additions and 77 deletions.
192 changes: 115 additions & 77 deletions block/curl.c
View file
Expand Up @@ -110,6 +110,7 @@ typedef struct BDRVCURLState {
size_t readahead_size;
bool sslverify;
bool accept_range;
AioContext *aio_context;
} BDRVCURLState;

static void curl_clean_state(CURLState *s);
Expand All @@ -134,25 +135,29 @@ static int curl_timer_cb(CURLM *multi, long timeout_ms, void *opaque)
#endif

static int curl_sock_cb(CURL *curl, curl_socket_t fd, int action,
void *s, void *sp)
void *userp, void *sp)
{
BDRVCURLState *s;
CURLState *state = NULL;
curl_easy_getinfo(curl, CURLINFO_PRIVATE, (char **)&state);
state->sock_fd = fd;
s = state->s;

DPRINTF("CURL (AIO): Sock action %d on fd %d\n", action, fd);
switch (action) {
case CURL_POLL_IN:
qemu_aio_set_fd_handler(fd, curl_multi_read, NULL, state);
aio_set_fd_handler(s->aio_context, fd, curl_multi_read,
NULL, state);
break;
case CURL_POLL_OUT:
qemu_aio_set_fd_handler(fd, NULL, curl_multi_do, state);
aio_set_fd_handler(s->aio_context, fd, NULL, curl_multi_do, state);
break;
case CURL_POLL_INOUT:
qemu_aio_set_fd_handler(fd, curl_multi_read, curl_multi_do, state);
aio_set_fd_handler(s->aio_context, fd, curl_multi_read,
curl_multi_do, state);
break;
case CURL_POLL_REMOVE:
qemu_aio_set_fd_handler(fd, NULL, NULL, NULL);
aio_set_fd_handler(s->aio_context, fd, NULL, NULL, NULL);
break;
}

Expand Down Expand Up @@ -365,7 +370,7 @@ static CURLState *curl_init_state(BDRVCURLState *s)
break;
}
if (!state) {
qemu_aio_wait();
aio_poll(state->s->aio_context, true);
}
} while(!state);

Expand Down Expand Up @@ -422,6 +427,51 @@ static void curl_parse_filename(const char *filename, QDict *options,
qdict_put(options, CURL_BLOCK_OPT_URL, qstring_from_str(filename));
}

static void curl_detach_aio_context(BlockDriverState *bs)
{
BDRVCURLState *s = bs->opaque;
int i;

for (i = 0; i < CURL_NUM_STATES; i++) {
if (s->states[i].in_use) {
curl_clean_state(&s->states[i]);
}
if (s->states[i].curl) {
curl_easy_cleanup(s->states[i].curl);
s->states[i].curl = NULL;
}
if (s->states[i].orig_buf) {
g_free(s->states[i].orig_buf);
s->states[i].orig_buf = NULL;
}
}
if (s->multi) {
curl_multi_cleanup(s->multi);
s->multi = NULL;
}

timer_del(&s->timer);
}

static void curl_attach_aio_context(BlockDriverState *bs,
AioContext *new_context)
{
BDRVCURLState *s = bs->opaque;

aio_timer_init(new_context, &s->timer,
QEMU_CLOCK_REALTIME, SCALE_NS,
curl_multi_timeout_do, s);

assert(!s->multi);
s->multi = curl_multi_init();
s->aio_context = new_context;
curl_multi_setopt(s->multi, CURLMOPT_SOCKETFUNCTION, curl_sock_cb);
#ifdef NEED_CURL_TIMER_CALLBACK
curl_multi_setopt(s->multi, CURLMOPT_TIMERDATA, s);
curl_multi_setopt(s->multi, CURLMOPT_TIMERFUNCTION, curl_timer_cb);
#endif
}

static QemuOptsList runtime_opts = {
.name = "curl",
.head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
Expand Down Expand Up @@ -491,6 +541,7 @@ static int curl_open(BlockDriverState *bs, QDict *options, int flags,
}

DPRINTF("CURL: Opening %s\n", file);
s->aio_context = bdrv_get_aio_context(bs);
s->url = g_strdup(file);
state = curl_init_state(s);
if (!state)
Expand Down Expand Up @@ -523,19 +574,7 @@ static int curl_open(BlockDriverState *bs, QDict *options, int flags,
curl_easy_cleanup(state->curl);
state->curl = NULL;

aio_timer_init(bdrv_get_aio_context(bs), &s->timer,
QEMU_CLOCK_REALTIME, SCALE_NS,
curl_multi_timeout_do, s);

// Now we know the file exists and its size, so let's
// initialize the multi interface!

s->multi = curl_multi_init();
curl_multi_setopt(s->multi, CURLMOPT_SOCKETFUNCTION, curl_sock_cb);
#ifdef NEED_CURL_TIMER_CALLBACK
curl_multi_setopt(s->multi, CURLMOPT_TIMERDATA, s);
curl_multi_setopt(s->multi, CURLMOPT_TIMERFUNCTION, curl_timer_cb);
#endif
curl_attach_aio_context(bs, bdrv_get_aio_context(bs));

qemu_opts_del(opts);
return 0;
Expand Down Expand Up @@ -630,33 +669,17 @@ static BlockDriverAIOCB *curl_aio_readv(BlockDriverState *bs,
acb->sector_num = sector_num;
acb->nb_sectors = nb_sectors;

acb->bh = qemu_bh_new(curl_readv_bh_cb, acb);
acb->bh = aio_bh_new(bdrv_get_aio_context(bs), curl_readv_bh_cb, acb);
qemu_bh_schedule(acb->bh);
return &acb->common;
}

static void curl_close(BlockDriverState *bs)
{
BDRVCURLState *s = bs->opaque;
int i;

DPRINTF("CURL: Close\n");
for (i=0; i<CURL_NUM_STATES; i++) {
if (s->states[i].in_use)
curl_clean_state(&s->states[i]);
if (s->states[i].curl) {
curl_easy_cleanup(s->states[i].curl);
s->states[i].curl = NULL;
}
if (s->states[i].orig_buf) {
g_free(s->states[i].orig_buf);
s->states[i].orig_buf = NULL;
}
}
if (s->multi)
curl_multi_cleanup(s->multi);

timer_del(&s->timer);
curl_detach_aio_context(bs);

g_free(s->url);
}
Expand All @@ -668,68 +691,83 @@ static int64_t curl_getlength(BlockDriverState *bs)
}

static BlockDriver bdrv_http = {
.format_name = "http",
.protocol_name = "http",
.format_name = "http",
.protocol_name = "http",

.instance_size = sizeof(BDRVCURLState),
.bdrv_parse_filename = curl_parse_filename,
.bdrv_file_open = curl_open,
.bdrv_close = curl_close,
.bdrv_getlength = curl_getlength,

.instance_size = sizeof(BDRVCURLState),
.bdrv_parse_filename = curl_parse_filename,
.bdrv_file_open = curl_open,
.bdrv_close = curl_close,
.bdrv_getlength = curl_getlength,
.bdrv_aio_readv = curl_aio_readv,

.bdrv_aio_readv = curl_aio_readv,
.bdrv_detach_aio_context = curl_detach_aio_context,
.bdrv_attach_aio_context = curl_attach_aio_context,
};

static BlockDriver bdrv_https = {
.format_name = "https",
.protocol_name = "https",
.format_name = "https",
.protocol_name = "https",

.instance_size = sizeof(BDRVCURLState),
.bdrv_parse_filename = curl_parse_filename,
.bdrv_file_open = curl_open,
.bdrv_close = curl_close,
.bdrv_getlength = curl_getlength,
.instance_size = sizeof(BDRVCURLState),
.bdrv_parse_filename = curl_parse_filename,
.bdrv_file_open = curl_open,
.bdrv_close = curl_close,
.bdrv_getlength = curl_getlength,

.bdrv_aio_readv = curl_aio_readv,
.bdrv_aio_readv = curl_aio_readv,

.bdrv_detach_aio_context = curl_detach_aio_context,
.bdrv_attach_aio_context = curl_attach_aio_context,
};

static BlockDriver bdrv_ftp = {
.format_name = "ftp",
.protocol_name = "ftp",
.format_name = "ftp",
.protocol_name = "ftp",

.instance_size = sizeof(BDRVCURLState),
.bdrv_parse_filename = curl_parse_filename,
.bdrv_file_open = curl_open,
.bdrv_close = curl_close,
.bdrv_getlength = curl_getlength,

.instance_size = sizeof(BDRVCURLState),
.bdrv_parse_filename = curl_parse_filename,
.bdrv_file_open = curl_open,
.bdrv_close = curl_close,
.bdrv_getlength = curl_getlength,
.bdrv_aio_readv = curl_aio_readv,

.bdrv_aio_readv = curl_aio_readv,
.bdrv_detach_aio_context = curl_detach_aio_context,
.bdrv_attach_aio_context = curl_attach_aio_context,
};

static BlockDriver bdrv_ftps = {
.format_name = "ftps",
.protocol_name = "ftps",
.format_name = "ftps",
.protocol_name = "ftps",

.instance_size = sizeof(BDRVCURLState),
.bdrv_parse_filename = curl_parse_filename,
.bdrv_file_open = curl_open,
.bdrv_close = curl_close,
.bdrv_getlength = curl_getlength,
.instance_size = sizeof(BDRVCURLState),
.bdrv_parse_filename = curl_parse_filename,
.bdrv_file_open = curl_open,
.bdrv_close = curl_close,
.bdrv_getlength = curl_getlength,

.bdrv_aio_readv = curl_aio_readv,
.bdrv_aio_readv = curl_aio_readv,

.bdrv_detach_aio_context = curl_detach_aio_context,
.bdrv_attach_aio_context = curl_attach_aio_context,
};

static BlockDriver bdrv_tftp = {
.format_name = "tftp",
.protocol_name = "tftp",
.format_name = "tftp",
.protocol_name = "tftp",

.instance_size = sizeof(BDRVCURLState),
.bdrv_parse_filename = curl_parse_filename,
.bdrv_file_open = curl_open,
.bdrv_close = curl_close,
.bdrv_getlength = curl_getlength,

.instance_size = sizeof(BDRVCURLState),
.bdrv_parse_filename = curl_parse_filename,
.bdrv_file_open = curl_open,
.bdrv_close = curl_close,
.bdrv_getlength = curl_getlength,
.bdrv_aio_readv = curl_aio_readv,

.bdrv_aio_readv = curl_aio_readv,
.bdrv_detach_aio_context = curl_detach_aio_context,
.bdrv_attach_aio_context = curl_attach_aio_context,
};

static void curl_block_init(void)
Expand Down

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