diff options
author | Peter Maydell <peter.maydell@linaro.org> | 2019-06-13 18:17:32 +0100 |
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committer | Peter Maydell <peter.maydell@linaro.org> | 2019-06-13 18:17:32 +0100 |
commit | d1bf88e56f46c75d472dc60c02bbbc7b474519f9 (patch) | |
tree | f773f3c6540d6e9ad94ee83b0a8b45843f77fe42 | |
parent | 650a379d505bf558bcb41124bc6c951a76cbc113 (diff) | |
parent | 611ae1d71647c58b23dc2c116a946884ce30abf8 (diff) | |
download | qemu-d1bf88e56f46c75d472dc60c02bbbc7b474519f9.zip qemu-d1bf88e56f46c75d472dc60c02bbbc7b474519f9.tar.gz qemu-d1bf88e56f46c75d472dc60c02bbbc7b474519f9.tar.bz2 |
Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2019-06-13' into staging
nbd patches for 2019-06-13
- add 'qemu-nbd --pid-file'
- NBD-related iotest improvements
- NBD code refactoring in preparation for reconnect
# gpg: Signature made Thu 13 Jun 2019 16:37:58 BST
# gpg: using RSA key A7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>" [full]
# gpg: aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>" [full]
# gpg: aka "[jpeg image of size 6874]" [full]
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2 F3AA A7A1 6B4A 2527 436A
* remotes/ericb/tags/pull-nbd-2019-06-13:
block/nbd: merge NBDClientSession struct back to BDRVNBDState
block/nbd: merge nbd-client.* to nbd.c
block/nbd-client: drop stale logout
nbd/server: Nicer spelling of max BLOCK_STATUS reply length
iotests: Let 233 run concurrently
iotests: Use qemu-nbd's --pid-file
qemu-nbd: Do not close stderr
iotests.py: Add qemu_nbd_early_pipe()
qemu-nbd: Add --pid-file option
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
-rw-r--r-- | block/Makefile.objs | 2 | ||||
-rw-r--r-- | block/nbd-client.c | 1226 | ||||
-rw-r--r-- | block/nbd-client.h | 71 | ||||
-rw-r--r-- | block/nbd.c | 1282 | ||||
-rw-r--r-- | block/trace-events | 4 | ||||
-rw-r--r-- | nbd/server.c | 13 | ||||
-rw-r--r-- | qemu-nbd.c | 14 | ||||
-rw-r--r-- | qemu-nbd.texi | 2 | ||||
-rwxr-xr-x | tests/qemu-iotests/147 | 4 | ||||
-rwxr-xr-x | tests/qemu-iotests/233 | 1 | ||||
-rw-r--r-- | tests/qemu-iotests/common.nbd | 94 | ||||
-rw-r--r-- | tests/qemu-iotests/common.rc | 6 | ||||
-rw-r--r-- | tests/qemu-iotests/iotests.py | 9 |
13 files changed, 1326 insertions, 1402 deletions
diff --git a/block/Makefile.objs b/block/Makefile.objs index ae11605..dbd1522 100644 --- a/block/Makefile.objs +++ b/block/Makefile.objs @@ -22,7 +22,7 @@ block-obj-y += null.o mirror.o commit.o io.o create.o block-obj-y += throttle-groups.o block-obj-$(CONFIG_LINUX) += nvme.o -block-obj-y += nbd.o nbd-client.o +block-obj-y += nbd.o block-obj-$(CONFIG_SHEEPDOG) += sheepdog.o block-obj-$(CONFIG_LIBISCSI) += iscsi.o block-obj-$(if $(CONFIG_LIBISCSI),y,n) += iscsi-opts.o diff --git a/block/nbd-client.c b/block/nbd-client.c deleted file mode 100644 index 790ecc1..0000000 --- a/block/nbd-client.c +++ /dev/null @@ -1,1226 +0,0 @@ -/* - * QEMU Block driver for NBD - * - * Copyright (C) 2016 Red Hat, Inc. - * Copyright (C) 2008 Bull S.A.S. - * Author: Laurent Vivier <Laurent.Vivier@bull.net> - * - * Some parts: - * Copyright (C) 2007 Anthony Liguori <anthony@codemonkey.ws> - * - * Permission is hereby granted, free of charge, to any person obtaining a copy - * of this software and associated documentation files (the "Software"), to deal - * in the Software without restriction, including without limitation the rights - * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell - * copies of the Software, and to permit persons to whom the Software is - * furnished to do so, subject to the following conditions: - * - * The above copyright notice and this permission notice shall be included in - * all copies or substantial portions of the Software. - * - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR - * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL - * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER - * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, - * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN - * THE SOFTWARE. - */ - -#include "qemu/osdep.h" - -#include "trace.h" -#include "qapi/error.h" -#include "nbd-client.h" - -#define HANDLE_TO_INDEX(bs, handle) ((handle) ^ (uint64_t)(intptr_t)(bs)) -#define INDEX_TO_HANDLE(bs, index) ((index) ^ (uint64_t)(intptr_t)(bs)) - -static void nbd_recv_coroutines_wake_all(NBDClientSession *s) -{ - int i; - - for (i = 0; i < MAX_NBD_REQUESTS; i++) { - NBDClientRequest *req = &s->requests[i]; - - if (req->coroutine && req->receiving) { - aio_co_wake(req->coroutine); - } - } -} - -static void nbd_teardown_connection(BlockDriverState *bs) -{ - NBDClientSession *client = nbd_get_client_session(bs); - - assert(client->ioc); - - /* finish any pending coroutines */ - qio_channel_shutdown(client->ioc, - QIO_CHANNEL_SHUTDOWN_BOTH, - NULL); - BDRV_POLL_WHILE(bs, client->connection_co); - - nbd_client_detach_aio_context(bs); - object_unref(OBJECT(client->sioc)); - client->sioc = NULL; - object_unref(OBJECT(client->ioc)); - client->ioc = NULL; -} - -static coroutine_fn void nbd_connection_entry(void *opaque) -{ - NBDClientSession *s = opaque; - uint64_t i; - int ret = 0; - Error *local_err = NULL; - - while (!s->quit) { - /* - * The NBD client can only really be considered idle when it has - * yielded from qio_channel_readv_all_eof(), waiting for data. This is - * the point where the additional scheduled coroutine entry happens - * after nbd_client_attach_aio_context(). - * - * Therefore we keep an additional in_flight reference all the time and - * only drop it temporarily here. - */ - assert(s->reply.handle == 0); - ret = nbd_receive_reply(s->bs, s->ioc, &s->reply, &local_err); - - if (local_err) { - trace_nbd_read_reply_entry_fail(ret, error_get_pretty(local_err)); - error_free(local_err); - } - if (ret <= 0) { - break; - } - - /* There's no need for a mutex on the receive side, because the - * handler acts as a synchronization point and ensures that only - * one coroutine is called until the reply finishes. - */ - i = HANDLE_TO_INDEX(s, s->reply.handle); - if (i >= MAX_NBD_REQUESTS || - !s->requests[i].coroutine || - !s->requests[i].receiving || - (nbd_reply_is_structured(&s->reply) && !s->info.structured_reply)) - { - break; - } - - /* We're woken up again by the request itself. Note that there - * is no race between yielding and reentering connection_co. This - * is because: - * - * - if the request runs on the same AioContext, it is only - * entered after we yield - * - * - if the request runs on a different AioContext, reentering - * connection_co happens through a bottom half, which can only - * run after we yield. - */ - aio_co_wake(s->requests[i].coroutine); - qemu_coroutine_yield(); - } - - s->quit = true; - nbd_recv_coroutines_wake_all(s); - bdrv_dec_in_flight(s->bs); - - s->connection_co = NULL; - aio_wait_kick(); -} - -static int nbd_co_send_request(BlockDriverState *bs, - NBDRequest *request, - QEMUIOVector *qiov) -{ - NBDClientSession *s = nbd_get_client_session(bs); - int rc, i; - - qemu_co_mutex_lock(&s->send_mutex); - while (s->in_flight == MAX_NBD_REQUESTS) { - qemu_co_queue_wait(&s->free_sema, &s->send_mutex); - } - s->in_flight++; - - for (i = 0; i < MAX_NBD_REQUESTS; i++) { - if (s->requests[i].coroutine == NULL) { - break; - } - } - - g_assert(qemu_in_coroutine()); - assert(i < MAX_NBD_REQUESTS); - - s->requests[i].coroutine = qemu_coroutine_self(); - s->requests[i].offset = request->from; - s->requests[i].receiving = false; - - request->handle = INDEX_TO_HANDLE(s, i); - - if (s->quit) { - rc = -EIO; - goto err; - } - assert(s->ioc); - - if (qiov) { - qio_channel_set_cork(s->ioc, true); - rc = nbd_send_request(s->ioc, request); - if (rc >= 0 && !s->quit) { - if (qio_channel_writev_all(s->ioc, qiov->iov, qiov->niov, - NULL) < 0) { - rc = -EIO; - } - } else if (rc >= 0) { - rc = -EIO; - } - qio_channel_set_cork(s->ioc, false); - } else { - rc = nbd_send_request(s->ioc, request); - } - -err: - if (rc < 0) { - s->quit = true; - s->requests[i].coroutine = NULL; - s->in_flight--; - qemu_co_queue_next(&s->free_sema); - } - qemu_co_mutex_unlock(&s->send_mutex); - return rc; -} - -static inline uint16_t payload_advance16(uint8_t **payload) -{ - *payload += 2; - return lduw_be_p(*payload - 2); -} - -static inline uint32_t payload_advance32(uint8_t **payload) -{ - *payload += 4; - return ldl_be_p(*payload - 4); -} - -static inline uint64_t payload_advance64(uint8_t **payload) -{ - *payload += 8; - return ldq_be_p(*payload - 8); -} - -static int nbd_parse_offset_hole_payload(NBDClientSession *client, - NBDStructuredReplyChunk *chunk, - uint8_t *payload, uint64_t orig_offset, - QEMUIOVector *qiov, Error **errp) -{ - uint64_t offset; - uint32_t hole_size; - - if (chunk->length != sizeof(offset) + sizeof(hole_size)) { - error_setg(errp, "Protocol error: invalid payload for " - "NBD_REPLY_TYPE_OFFSET_HOLE"); - return -EINVAL; - } - - offset = payload_advance64(&payload); - hole_size = payload_advance32(&payload); - - if (!hole_size || offset < orig_offset || hole_size > qiov->size || - offset > orig_offset + qiov->size - hole_size) { - error_setg(errp, "Protocol error: server sent chunk exceeding requested" - " region"); - return -EINVAL; - } - if (client->info.min_block && - !QEMU_IS_ALIGNED(hole_size, client->info.min_block)) { - trace_nbd_structured_read_compliance("hole"); - } - - qemu_iovec_memset(qiov, offset - orig_offset, 0, hole_size); - - return 0; -} - -/* nbd_parse_blockstatus_payload - * Based on our request, we expect only one extent in reply, for the - * base:allocation context. - */ -static int nbd_parse_blockstatus_payload(NBDClientSession *client, - NBDStructuredReplyChunk *chunk, - uint8_t *payload, uint64_t orig_length, - NBDExtent *extent, Error **errp) -{ - uint32_t context_id; - - /* The server succeeded, so it must have sent [at least] one extent */ - if (chunk->length < sizeof(context_id) + sizeof(*extent)) { - error_setg(errp, "Protocol error: invalid payload for " - "NBD_REPLY_TYPE_BLOCK_STATUS"); - return -EINVAL; - } - - context_id = payload_advance32(&payload); - if (client->info.context_id != context_id) { - error_setg(errp, "Protocol error: unexpected context id %d for " - "NBD_REPLY_TYPE_BLOCK_STATUS, when negotiated context " - "id is %d", context_id, - client->info.context_id); - return -EINVAL; - } - - extent->length = payload_advance32(&payload); - extent->flags = payload_advance32(&payload); - - if (extent->length == 0) { - error_setg(errp, "Protocol error: server sent status chunk with " - "zero length"); - return -EINVAL; - } - - /* - * A server sending unaligned block status is in violation of the - * protocol, but as qemu-nbd 3.1 is such a server (at least for - * POSIX files that are not a multiple of 512 bytes, since qemu - * rounds files up to 512-byte multiples but lseek(SEEK_HOLE) - * still sees an implicit hole beyond the real EOF), it's nicer to - * work around the misbehaving server. If the request included - * more than the final unaligned block, truncate it back to an - * aligned result; if the request was only the final block, round - * up to the full block and change the status to fully-allocated - * (always a safe status, even if it loses information). - */ - if (client->info.min_block && !QEMU_IS_ALIGNED(extent->length, - client->info.min_block)) { - trace_nbd_parse_blockstatus_compliance("extent length is unaligned"); - if (extent->length > client->info.min_block) { - extent->length = QEMU_ALIGN_DOWN(extent->length, - client->info.min_block); - } else { - extent->length = client->info.min_block; - extent->flags = 0; - } - } - - /* - * We used NBD_CMD_FLAG_REQ_ONE, so the server should not have - * sent us any more than one extent, nor should it have included - * status beyond our request in that extent. However, it's easy - * enough to ignore the server's noncompliance without killing the - * connection; just ignore trailing extents, and clamp things to - * the length of our request. - */ - if (chunk->length > sizeof(context_id) + sizeof(*extent)) { - trace_nbd_parse_blockstatus_compliance("more than one extent"); - } - if (extent->length > orig_length) { - extent->length = orig_length; - trace_nbd_parse_blockstatus_compliance("extent length too large"); - } - - return 0; -} - -/* nbd_parse_error_payload - * on success @errp contains message describing nbd error reply - */ -static int nbd_parse_error_payload(NBDStructuredReplyChunk *chunk, - uint8_t *payload, int *request_ret, - Error **errp) -{ - uint32_t error; - uint16_t message_size; - - assert(chunk->type & (1 << 15)); - - if (chunk->length < sizeof(error) + sizeof(message_size)) { - error_setg(errp, - "Protocol error: invalid payload for structured error"); - return -EINVAL; - } - - error = nbd_errno_to_system_errno(payload_advance32(&payload)); - if (error == 0) { - error_setg(errp, "Protocol error: server sent structured error chunk " - "with error = 0"); - return -EINVAL; - } - - *request_ret = -error; - message_size = payload_advance16(&payload); - - if (message_size > chunk->length - sizeof(error) - sizeof(message_size)) { - error_setg(errp, "Protocol error: server sent structured error chunk " - "with incorrect message size"); - return -EINVAL; - } - - /* TODO: Add a trace point to mention the server complaint */ - - /* TODO handle ERROR_OFFSET */ - - return 0; -} - -static int nbd_co_receive_offset_data_payload(NBDClientSession *s, - uint64_t orig_offset, - QEMUIOVector *qiov, Error **errp) -{ - QEMUIOVector sub_qiov; - uint64_t offset; - size_t data_size; - int ret; - NBDStructuredReplyChunk *chunk = &s->reply.structured; - - assert(nbd_reply_is_structured(&s->reply)); - - /* The NBD spec requires at least one byte of payload */ - if (chunk->length <= sizeof(offset)) { - error_setg(errp, "Protocol error: invalid payload for " - "NBD_REPLY_TYPE_OFFSET_DATA"); - return -EINVAL; - } - - if (nbd_read64(s->ioc, &offset, "OFFSET_DATA offset", errp) < 0) { - return -EIO; - } - - data_size = chunk->length - sizeof(offset); - assert(data_size); - if (offset < orig_offset || data_size > qiov->size || - offset > orig_offset + qiov->size - data_size) { - error_setg(errp, "Protocol error: server sent chunk exceeding requested" - " region"); - return -EINVAL; - } - if (s->info.min_block && !QEMU_IS_ALIGNED(data_size, s->info.min_block)) { - trace_nbd_structured_read_compliance("data"); - } - - qemu_iovec_init(&sub_qiov, qiov->niov); - qemu_iovec_concat(&sub_qiov, qiov, offset - orig_offset, data_size); - ret = qio_channel_readv_all(s->ioc, sub_qiov.iov, sub_qiov.niov, errp); - qemu_iovec_destroy(&sub_qiov); - - return ret < 0 ? -EIO : 0; -} - -#define NBD_MAX_MALLOC_PAYLOAD 1000 -/* nbd_co_receive_structured_payload - */ -static coroutine_fn int nbd_co_receive_structured_payload( - NBDClientSession *s, void **payload, Error **errp) -{ - int ret; - uint32_t len; - - assert(nbd_reply_is_structured(&s->reply)); - - len = s->reply.structured.length; - - if (len == 0) { - return 0; - } - - if (payload == NULL) { - error_setg(errp, "Unexpected structured payload"); - return -EINVAL; - } - - if (len > NBD_MAX_MALLOC_PAYLOAD) { - error_setg(errp, "Payload too large"); - return -EINVAL; - } - - *payload = g_new(char, len); - ret = nbd_read(s->ioc, *payload, len, "structured payload", errp); - if (ret < 0) { - g_free(*payload); - *payload = NULL; - return ret; - } - - return 0; -} - -/* nbd_co_do_receive_one_chunk - * for simple reply: - * set request_ret to received reply error - * if qiov is not NULL: read payload to @qiov - * for structured reply chunk: - * if error chunk: read payload, set @request_ret, do not set @payload - * else if offset_data chunk: read payload data to @qiov, do not set @payload - * else: read payload to @payload - * - * If function fails, @errp contains corresponding error message, and the - * connection with the server is suspect. If it returns 0, then the - * transaction succeeded (although @request_ret may be a negative errno - * corresponding to the server's error reply), and errp is unchanged. - */ -static coroutine_fn int nbd_co_do_receive_one_chunk( - NBDClientSession *s, uint64_t handle, bool only_structured, - int *request_ret, QEMUIOVector *qiov, void **payload, Error **errp) -{ - int ret; - int i = HANDLE_TO_INDEX(s, handle); - void *local_payload = NULL; - NBDStructuredReplyChunk *chunk; - - if (payload) { - *payload = NULL; - } - *request_ret = 0; - - /* Wait until we're woken up by nbd_connection_entry. */ - s->requests[i].receiving = true; - qemu_coroutine_yield(); - s->requests[i].receiving = false; - if (s->quit) { - error_setg(errp, "Connection closed"); - return -EIO; - } - assert(s->ioc); - - assert(s->reply.handle == handle); - - if (nbd_reply_is_simple(&s->reply)) { - if (only_structured) { - error_setg(errp, "Protocol error: simple reply when structured " - "reply chunk was expected"); - return -EINVAL; - } - - *request_ret = -nbd_errno_to_system_errno(s->reply.simple.error); - if (*request_ret < 0 || !qiov) { - return 0; - } - - return qio_channel_readv_all(s->ioc, qiov->iov, qiov->niov, - errp) < 0 ? -EIO : 0; - } - - /* handle structured reply chunk */ - assert(s->info.structured_reply); - chunk = &s->reply.structured; - - if (chunk->type == NBD_REPLY_TYPE_NONE) { - if (!(chunk->flags & NBD_REPLY_FLAG_DONE)) { - error_setg(errp, "Protocol error: NBD_REPLY_TYPE_NONE chunk without" - " NBD_REPLY_FLAG_DONE flag set"); - return -EINVAL; - } - if (chunk->length) { - error_setg(errp, "Protocol error: NBD_REPLY_TYPE_NONE chunk with" - " nonzero length"); - return -EINVAL; - } - return 0; - } - - if (chunk->type == NBD_REPLY_TYPE_OFFSET_DATA) { - if (!qiov) { - error_setg(errp, "Unexpected NBD_REPLY_TYPE_OFFSET_DATA chunk"); - return -EINVAL; - } - - return nbd_co_receive_offset_data_payload(s, s->requests[i].offset, - qiov, errp); - } - - if (nbd_reply_type_is_error(chunk->type)) { - payload = &local_payload; - } - - ret = nbd_co_receive_structured_payload(s, payload, errp); - if (ret < 0) { - return ret; - } - - if (nbd_reply_type_is_error(chunk->type)) { - ret = nbd_parse_error_payload(chunk, local_payload, request_ret, errp); - g_free(local_payload); - return ret; - } - - return 0; -} - -/* nbd_co_receive_one_chunk - * Read reply, wake up connection_co and set s->quit if needed. - * Return value is a fatal error code or normal nbd reply error code - */ -static coroutine_fn int nbd_co_receive_one_chunk( - NBDClientSession *s, uint64_t handle, bool only_structured, - int *request_ret, QEMUIOVector *qiov, NBDReply *reply, void **payload, - Error **errp) -{ - int ret = nbd_co_do_receive_one_chunk(s, handle, only_structured, - request_ret, qiov, payload, errp); - - if (ret < 0) { - s->quit = true; - } else { - /* For assert at loop start in nbd_connection_entry */ - if (reply) { - *reply = s->reply; - } - s->reply.handle = 0; - } - - if (s->connection_co) { - aio_co_wake(s->connection_co); - } - - return ret; -} - -typedef struct NBDReplyChunkIter { - int ret; - int request_ret; - Error *err; - bool done, only_structured; -} NBDReplyChunkIter; - -static void nbd_iter_channel_error(NBDReplyChunkIter *iter, - int ret, Error **local_err) -{ - assert(ret < 0); - - if (!iter->ret) { - iter->ret = ret; - error_propagate(&iter->err, *local_err); - } else { - error_free(*local_err); - } - - *local_err = NULL; -} - -static void nbd_iter_request_error(NBDReplyChunkIter *iter, int ret) -{ - assert(ret < 0); - - if (!iter->request_ret) { - iter->request_ret = ret; - } -} - -/* NBD_FOREACH_REPLY_CHUNK - */ -#define NBD_FOREACH_REPLY_CHUNK(s, iter, handle, structured, \ - qiov, reply, payload) \ - for (iter = (NBDReplyChunkIter) { .only_structured = structured }; \ - nbd_reply_chunk_iter_receive(s, &iter, handle, qiov, reply, payload);) - -/* nbd_reply_chunk_iter_receive - */ -static bool nbd_reply_chunk_iter_receive(NBDClientSession *s, - NBDReplyChunkIter *iter, - uint64_t handle, - QEMUIOVector *qiov, NBDReply *reply, - void **payload) -{ - int ret, request_ret; - NBDReply local_reply; - NBDStructuredReplyChunk *chunk; - Error *local_err = NULL; - if (s->quit) { - error_setg(&local_err, "Connection closed"); - nbd_iter_channel_error(iter, -EIO, &local_err); - goto break_loop; - } - - if (iter->done) { - /* Previous iteration was last. */ - goto break_loop; - } - - if (reply == NULL) { - reply = &local_reply; - } - - ret = nbd_co_receive_one_chunk(s, handle, iter->only_structured, - &request_ret, qiov, reply, payload, - &local_err); - if (ret < 0) { - nbd_iter_channel_error(iter, ret, &local_err); - } else if (request_ret < 0) { - nbd_iter_request_error(iter, request_ret); - } - - /* Do not execute the body of NBD_FOREACH_REPLY_CHUNK for simple reply. */ - if (nbd_reply_is_simple(reply) || s->quit) { - goto break_loop; - } - - chunk = &reply->structured; - iter->only_structured = true; - - if (chunk->type == NBD_REPLY_TYPE_NONE) { - /* NBD_REPLY_FLAG_DONE is already checked in nbd_co_receive_one_chunk */ - assert(chunk->flags & NBD_REPLY_FLAG_DONE); - goto break_loop; - } - - if (chunk->flags & NBD_REPLY_FLAG_DONE) { - /* This iteration is last. */ - iter->done = true; - } - - /* Execute the loop body */ - return true; - -break_loop: - s->requests[HANDLE_TO_INDEX(s, handle)].coroutine = NULL; - - qemu_co_mutex_lock(&s->send_mutex); - s->in_flight--; - qemu_co_queue_next(&s->free_sema); - qemu_co_mutex_unlock(&s->send_mutex); - - return false; -} - -static int nbd_co_receive_return_code(NBDClientSession *s, uint64_t handle, - int *request_ret, Error **errp) -{ - NBDReplyChunkIter iter; - - NBD_FOREACH_REPLY_CHUNK(s, iter, handle, false, NULL, NULL, NULL) { - /* nbd_reply_chunk_iter_receive does all the work */ - } - - error_propagate(errp, iter.err); - *request_ret = iter.request_ret; - return iter.ret; -} - -static int nbd_co_receive_cmdread_reply(NBDClientSession *s, uint64_t handle, - uint64_t offset, QEMUIOVector *qiov, - int *request_ret, Error **errp) -{ - NBDReplyChunkIter iter; - NBDReply reply; - void *payload = NULL; - Error *local_err = NULL; - - NBD_FOREACH_REPLY_CHUNK(s, iter, handle, s->info.structured_reply, - qiov, &reply, &payload) - { - int ret; - NBDStructuredReplyChunk *chunk = &reply.structured; - - assert(nbd_reply_is_structured(&reply)); - - switch (chunk->type) { - case NBD_REPLY_TYPE_OFFSET_DATA: - /* special cased in nbd_co_receive_one_chunk, data is already - * in qiov */ - break; - case NBD_REPLY_TYPE_OFFSET_HOLE: - ret = nbd_parse_offset_hole_payload(s, &reply.structured, payload, - offset, qiov, &local_err); - if (ret < 0) { - s->quit = true; - nbd_iter_channel_error(&iter, ret, &local_err); - } - break; - default: - if (!nbd_reply_type_is_error(chunk->type)) { - /* not allowed reply type */ - s->quit = true; - error_setg(&local_err, - "Unexpected reply type: %d (%s) for CMD_READ", - chunk->type, nbd_reply_type_lookup(chunk->type)); - nbd_iter_channel_error(&iter, -EINVAL, &local_err); - } - } - - g_free(payload); - payload = NULL; - } - - error_propagate(errp, iter.err); - *request_ret = iter.request_ret; - return iter.ret; -} - -static int nbd_co_receive_blockstatus_reply(NBDClientSession *s, - uint64_t handle, uint64_t length, - NBDExtent *extent, - int *request_ret, Error **errp) -{ - NBDReplyChunkIter iter; - NBDReply reply; - void *payload = NULL; - Error *local_err = NULL; - bool received = false; - - assert(!extent->length); - NBD_FOREACH_REPLY_CHUNK(s, iter, handle, false, NULL, &reply, &payload) { - int ret; - NBDStructuredReplyChunk *chunk = &reply.structured; - - assert(nbd_reply_is_structured(&reply)); - - switch (chunk->type) { - case NBD_REPLY_TYPE_BLOCK_STATUS: - if (received) { - s->quit = true; - error_setg(&local_err, "Several BLOCK_STATUS chunks in reply"); - nbd_iter_channel_error(&iter, -EINVAL, &local_err); - } - received = true; - - ret = nbd_parse_blockstatus_payload(s, &reply.structured, - payload, length, extent, - &local_err); - if (ret < 0) { - s->quit = true; - nbd_iter_channel_error(&iter, ret, &local_err); - } - break; - default: - if (!nbd_reply_type_is_error(chunk->type)) { - s->quit = true; - error_setg(&local_err, - "Unexpected reply type: %d (%s) " - "for CMD_BLOCK_STATUS", - chunk->type, nbd_reply_type_lookup(chunk->type)); - nbd_iter_channel_error(&iter, -EINVAL, &local_err); - } - } - - g_free(payload); - payload = NULL; - } - - if (!extent->length && !iter.request_ret) { - error_setg(&local_err, "Server did not reply with any status extents"); - nbd_iter_channel_error(&iter, -EIO, &local_err); - } - - error_propagate(errp, iter.err); - *request_ret = iter.request_ret; - return iter.ret; -} - -static int nbd_co_request(BlockDriverState *bs, NBDRequest *request, - QEMUIOVector *write_qiov) -{ - int ret, request_ret; - Error *local_err = NULL; - NBDClientSession *client = nbd_get_client_session(bs); - - assert(request->type != NBD_CMD_READ); - if (write_qiov) { - assert(request->type == NBD_CMD_WRITE); - assert(request->len == iov_size(write_qiov->iov, write_qiov->niov)); - } else { - assert(request->type != NBD_CMD_WRITE); - } - ret = nbd_co_send_request(bs, request, write_qiov); - if (ret < 0) { - return ret; - } - - ret = nbd_co_receive_return_code(client, request->handle, - &request_ret, &local_err); - if (local_err) { - trace_nbd_co_request_fail(request->from, request->len, request->handle, - request->flags, request->type, - nbd_cmd_lookup(request->type), - ret, error_get_pretty(local_err)); - error_free(local_err); - } - return ret ? ret : request_ret; -} - -int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset, - uint64_t bytes, QEMUIOVector *qiov, int flags) -{ - int ret, request_ret; - Error *local_err = NULL; - NBDClientSession *client = nbd_get_client_session(bs); - NBDRequest request = { - .type = NBD_CMD_READ, - .from = offset, - .len = bytes, - }; - - assert(bytes <= NBD_MAX_BUFFER_SIZE); - assert(!flags); - - if (!bytes) { - return 0; - } - /* - * Work around the fact that the block layer doesn't do - * byte-accurate sizing yet - if the read exceeds the server's - * advertised size because the block layer rounded size up, then - * truncate the request to the server and tail-pad with zero. - */ - if (offset >= client->info.size) { - assert(bytes < BDRV_SECTOR_SIZE); - qemu_iovec_memset(qiov, 0, 0, bytes); - return 0; - } - if (offset + bytes > client->info.size) { - uint64_t slop = offset + bytes - client->info.size; - - assert(slop < BDRV_SECTOR_SIZE); - qemu_iovec_memset(qiov, bytes - slop, 0, slop); - request.len -= slop; - } - - ret = nbd_co_send_request(bs, &request, NULL); - if (ret < 0) { - return ret; - } - - ret = nbd_co_receive_cmdread_reply(client, request.handle, offset, qiov, - &request_ret, &local_err); - if (local_err) { - trace_nbd_co_request_fail(request.from, request.len, request.handle, - request.flags, request.type, - nbd_cmd_lookup(request.type), - ret, error_get_pretty(local_err)); - error_free(local_err); - } - return ret ? ret : request_ret; -} - -int nbd_client_co_pwritev(BlockDriverState *bs, uint64_t offset, - uint64_t bytes, QEMUIOVector *qiov, int flags) -{ - NBDClientSession *client = nbd_get_client_session(bs); - NBDRequest request = { - .type = NBD_CMD_WRITE, - .from = offset, - .len = bytes, - }; - - assert(!(client->info.flags & NBD_FLAG_READ_ONLY)); - if (flags & BDRV_REQ_FUA) { - assert(client->info.flags & NBD_FLAG_SEND_FUA); - request.flags |= NBD_CMD_FLAG_FUA; - } - - assert(bytes <= NBD_MAX_BUFFER_SIZE); - - if (!bytes) { - return 0; - } - return nbd_co_request(bs, &request, qiov); -} - -int nbd_client_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset, - int bytes, BdrvRequestFlags flags) -{ - NBDClientSession *client = nbd_get_client_session(bs); - NBDRequest request = { - .type = NBD_CMD_WRITE_ZEROES, - .from = offset, - .len = bytes, - }; - - assert(!(client->info.flags & NBD_FLAG_READ_ONLY)); - if (!(client->info.flags & NBD_FLAG_SEND_WRITE_ZEROES)) { - return -ENOTSUP; - } - - if (flags & BDRV_REQ_FUA) { - assert(client->info.flags & NBD_FLAG_SEND_FUA); - request.flags |= NBD_CMD_FLAG_FUA; - } - if (!(flags & BDRV_REQ_MAY_UNMAP)) { - request.flags |= NBD_CMD_FLAG_NO_HOLE; - } - - if (!bytes) { - return 0; - } - return nbd_co_request(bs, &request, NULL); -} - -int nbd_client_co_flush(BlockDriverState *bs) -{ - NBDClientSession *client = nbd_get_client_session(bs); - NBDRequest request = { .type = NBD_CMD_FLUSH }; - - if (!(client->info.flags & NBD_FLAG_SEND_FLUSH)) { - return 0; - } - - request.from = 0; - request.len = 0; - - return nbd_co_request(bs, &request, NULL); -} - -int nbd_client_co_pdiscard(BlockDriverState *bs, int64_t offset, int bytes) -{ - NBDClientSession *client = nbd_get_client_session(bs); - NBDRequest request = { - .type = NBD_CMD_TRIM, - .from = offset, - .len = bytes, - }; - - assert(!(client->info.flags & NBD_FLAG_READ_ONLY)); - if (!(client->info.flags & NBD_FLAG_SEND_TRIM) || !bytes) { - return 0; - } - - return nbd_co_request(bs, &request, NULL); -} - -int coroutine_fn nbd_client_co_block_status(BlockDriverState *bs, - bool want_zero, - int64_t offset, int64_t bytes, - int64_t *pnum, int64_t *map, - BlockDriverState **file) -{ - int ret, request_ret; - NBDExtent extent = { 0 }; - NBDClientSession *client = nbd_get_client_session(bs); - Error *local_err = NULL; - - NBDRequest request = { - .type = NBD_CMD_BLOCK_STATUS, - .from = offset, - .len = MIN(MIN_NON_ZERO(QEMU_ALIGN_DOWN(INT_MAX, - bs->bl.request_alignment), - client->info.max_block), - MIN(bytes, client->info.size - offset)), - .flags = NBD_CMD_FLAG_REQ_ONE, - }; - - if (!client->info.base_allocation) { - *pnum = bytes; - *map = offset; - *file = bs; - return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID; - } - - /* - * Work around the fact that the block layer doesn't do - * byte-accurate sizing yet - if the status request exceeds the - * server's advertised size because the block layer rounded size - * up, we truncated the request to the server (above), or are - * called on just the hole. - */ - if (offset >= client->info.size) { - *pnum = bytes; - assert(bytes < BDRV_SECTOR_SIZE); - /* Intentionally don't report offset_valid for the hole */ - return BDRV_BLOCK_ZERO; - } - - if (client->info.min_block) { - assert(QEMU_IS_ALIGNED(request.len, client->info.min_block)); - } - ret = nbd_co_send_request(bs, &request, NULL); - if (ret < 0) { - return ret; - } - - ret = nbd_co_receive_blockstatus_reply(client, request.handle, bytes, - &extent, &request_ret, &local_err); - if (local_err) { - trace_nbd_co_request_fail(request.from, request.len, request.handle, - request.flags, request.type, - nbd_cmd_lookup(request.type), - ret, error_get_pretty(local_err)); - error_free(local_err); - } - if (ret < 0 || request_ret < 0) { - return ret ? ret : request_ret; - } - - assert(extent.length); - *pnum = extent.length; - *map = offset; - *file = bs; - return (extent.flags & NBD_STATE_HOLE ? 0 : BDRV_BLOCK_DATA) | - (extent.flags & NBD_STATE_ZERO ? BDRV_BLOCK_ZERO : 0) | - BDRV_BLOCK_OFFSET_VALID; -} - -void nbd_client_detach_aio_context(BlockDriverState *bs) -{ - NBDClientSession *client = nbd_get_client_session(bs); - qio_channel_detach_aio_context(QIO_CHANNEL(client->ioc)); -} - -static void nbd_client_attach_aio_context_bh(void *opaque) -{ - BlockDriverState *bs = opaque; - NBDClientSession *client = nbd_get_client_session(bs); - - /* The node is still drained, so we know the coroutine has yielded in - * nbd_read_eof(), the only place where bs->in_flight can reach 0, or it is - * entered for the first time. Both places are safe for entering the - * coroutine.*/ - qemu_aio_coroutine_enter(bs->aio_context, client->connection_co); - bdrv_dec_in_flight(bs); -} - -void nbd_client_attach_aio_context(BlockDriverState *bs, - AioContext *new_context) -{ - NBDClientSession *client = nbd_get_client_session(bs); - qio_channel_attach_aio_context(QIO_CHANNEL(client->ioc), new_context); - - bdrv_inc_in_flight(bs); - - /* Need to wait here for the BH to run because the BH must run while the - * node is still drained. */ - aio_wait_bh_oneshot(new_context, nbd_client_attach_aio_context_bh, bs); -} - -void nbd_client_close(BlockDriverState *bs) -{ - NBDClientSession *client = nbd_get_client_session(bs); - NBDRequest request = { .type = NBD_CMD_DISC }; - - assert(client->ioc); - - nbd_send_request(client->ioc, &request); - - nbd_teardown_connection(bs); -} - -static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr, - Error **errp) -{ - QIOChannelSocket *sioc; - Error *local_err = NULL; - - sioc = qio_channel_socket_new(); - qio_channel_set_name(QIO_CHANNEL(sioc), "nbd-client"); - - qio_channel_socket_connect_sync(sioc, saddr, &local_err); - if (local_err) { - object_unref(OBJECT(sioc)); - error_propagate(errp, local_err); - return NULL; - } - - qio_channel_set_delay(QIO_CHANNEL(sioc), false); - - return sioc; -} - -static int nbd_client_connect(BlockDriverState *bs, - SocketAddress *saddr, - const char *export, - QCryptoTLSCreds *tlscreds, - const char *hostname, - const char *x_dirty_bitmap, - Error **errp) -{ - NBDClientSession *client = nbd_get_client_session(bs); - int ret; - - /* - * establish TCP connection, return error if it fails - * TODO: Configurable retry-until-timeout behaviour. - */ - QIOChannelSocket *sioc = nbd_establish_connection(saddr, errp); - - if (!sioc) { - return -ECONNREFUSED; - } - - /* NBD handshake */ - logout("session init %s\n", export); - qio_channel_set_blocking(QIO_CHANNEL(sioc), true, NULL); - - client->info.request_sizes = true; - client->info.structured_reply = true; - client->info.base_allocation = true; - client->info.x_dirty_bitmap = g_strdup(x_dirty_bitmap); - client->info.name = g_strdup(export ?: ""); - ret = nbd_receive_negotiate(QIO_CHANNEL(sioc), tlscreds, hostname, - &client->ioc, &client->info, errp); - g_free(client->info.x_dirty_bitmap); - g_free(client->info.name); - if (ret < 0) { - logout("Failed to negotiate with the NBD server\n"); - object_unref(OBJECT(sioc)); - return ret; - } - if (x_dirty_bitmap && !client->info.base_allocation) { - error_setg(errp, "requested x-dirty-bitmap %s not found", - x_dirty_bitmap); - ret = -EINVAL; - goto fail; - } - if (client->info.flags & NBD_FLAG_READ_ONLY) { - ret = bdrv_apply_auto_read_only(bs, "NBD export is read-only", errp); - if (ret < 0) { - goto fail; - } - } - if (client->info.flags & NBD_FLAG_SEND_FUA) { - bs->supported_write_flags = BDRV_REQ_FUA; - bs->supported_zero_flags |= BDRV_REQ_FUA; - } - if (client->info.flags & NBD_FLAG_SEND_WRITE_ZEROES) { - bs->supported_zero_flags |= BDRV_REQ_MAY_UNMAP; - } - - client->sioc = sioc; - - if (!client->ioc) { - client->ioc = QIO_CHANNEL(sioc); - object_ref(OBJECT(client->ioc)); - } - - /* Now that we're connected, set the socket to be non-blocking and - * kick the reply mechanism. */ - qio_channel_set_blocking(QIO_CHANNEL(sioc), false, NULL); - client->connection_co = qemu_coroutine_create(nbd_connection_entry, client); - bdrv_inc_in_flight(bs); - nbd_client_attach_aio_context(bs, bdrv_get_aio_context(bs)); - - logout("Established connection with NBD server\n"); - return 0; - - fail: - /* - * We have connected, but must fail for other reasons. The - * connection is still blocking; send NBD_CMD_DISC as a courtesy - * to the server. - */ - { - NBDRequest request = { .type = NBD_CMD_DISC }; - - nbd_send_request(client->ioc ?: QIO_CHANNEL(sioc), &request); - - object_unref(OBJECT(sioc)); - - return ret; - } -} - -int nbd_client_init(BlockDriverState *bs, - SocketAddress *saddr, - const char *export, - QCryptoTLSCreds *tlscreds, - const char *hostname, - const char *x_dirty_bitmap, - Error **errp) -{ - NBDClientSession *client = nbd_get_client_session(bs); - - client->bs = bs; - qemu_co_mutex_init(&client->send_mutex); - qemu_co_queue_init(&client->free_sema); - - return nbd_client_connect(bs, saddr, export, tlscreds, hostname, - x_dirty_bitmap, errp); -} diff --git a/block/nbd-client.h b/block/nbd-client.h deleted file mode 100644 index 4587053..0000000 --- a/block/nbd-client.h +++ /dev/null @@ -1,71 +0,0 @@ -#ifndef NBD_CLIENT_H -#define NBD_CLIENT_H - -#include "block/nbd.h" -#include "block/block_int.h" -#include "io/channel-socket.h" - -/* #define DEBUG_NBD */ - -#if defined(DEBUG_NBD) -#define logout(fmt, ...) \ - fprintf(stderr, "nbd\t%-24s" fmt, __func__, ##__VA_ARGS__) -#else -#define logout(fmt, ...) ((void)0) -#endif - -#define MAX_NBD_REQUESTS 16 - -typedef struct { - Coroutine *coroutine; - uint64_t offset; /* original offset of the request */ - bool receiving; /* waiting for connection_co? */ -} NBDClientRequest; - -typedef struct NBDClientSession { - QIOChannelSocket *sioc; /* The master data channel */ - QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */ - NBDExportInfo info; - - CoMutex send_mutex; - CoQueue free_sema; - Coroutine *connection_co; - int in_flight; - - NBDClientRequest requests[MAX_NBD_REQUESTS]; - NBDReply reply; - BlockDriverState *bs; - bool quit; -} NBDClientSession; - -NBDClientSession *nbd_get_client_session(BlockDriverState *bs); - -int nbd_client_init(BlockDriverState *bs, - SocketAddress *saddr, - const char *export_name, - QCryptoTLSCreds *tlscreds, - const char *hostname, - const char *x_dirty_bitmap, - Error **errp); -void nbd_client_close(BlockDriverState *bs); - -int nbd_client_co_pdiscard(BlockDriverState *bs, int64_t offset, int bytes); -int nbd_client_co_flush(BlockDriverState *bs); -int nbd_client_co_pwritev(BlockDriverState *bs, uint64_t offset, - uint64_t bytes, QEMUIOVector *qiov, int flags); -int nbd_client_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset, - int bytes, BdrvRequestFlags flags); -int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset, - uint64_t bytes, QEMUIOVector *qiov, int flags); - -void nbd_client_detach_aio_context(BlockDriverState *bs); -void nbd_client_attach_aio_context(BlockDriverState *bs, - AioContext *new_context); - -int coroutine_fn nbd_client_co_block_status(BlockDriverState *bs, - bool want_zero, - int64_t offset, int64_t bytes, - int64_t *pnum, int64_t *map, - BlockDriverState **file); - -#endif /* NBD_CLIENT_H */ diff --git a/block/nbd.c b/block/nbd.c index 208be59..81edabb 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -1,6 +1,7 @@ /* * QEMU Block driver for NBD * + * Copyright (C) 2016 Red Hat, Inc. * Copyright (C) 2008 Bull S.A.S. * Author: Laurent Vivier <Laurent.Vivier@bull.net> * @@ -27,30 +28,1258 @@ */ #include "qemu/osdep.h" -#include "nbd-client.h" -#include "block/qdict.h" -#include "qapi/error.h" + +#include "trace.h" #include "qemu/uri.h" -#include "block/block_int.h" -#include "qemu/module.h" #include "qemu/option.h" +#include "qemu/cutils.h" + #include "qapi/qapi-visit-sockets.h" -#include "qapi/qobject-input-visitor.h" -#include "qapi/qobject-output-visitor.h" -#include "qapi/qmp/qdict.h" #include "qapi/qmp/qstring.h" -#include "qemu/cutils.h" + +#include "block/qdict.h" +#include "block/nbd.h" +#include "block/block_int.h" #define EN_OPTSTR ":exportname=" +#define MAX_NBD_REQUESTS 16 + +#define HANDLE_TO_INDEX(bs, handle) ((handle) ^ (uint64_t)(intptr_t)(bs)) +#define INDEX_TO_HANDLE(bs, index) ((index) ^ (uint64_t)(intptr_t)(bs)) + +typedef struct { + Coroutine *coroutine; + uint64_t offset; /* original offset of the request */ + bool receiving; /* waiting for connection_co? */ +} NBDClientRequest; typedef struct BDRVNBDState { - NBDClientSession client; + QIOChannelSocket *sioc; /* The master data channel */ + QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */ + NBDExportInfo info; + + CoMutex send_mutex; + CoQueue free_sema; + Coroutine *connection_co; + int in_flight; + + NBDClientRequest requests[MAX_NBD_REQUESTS]; + NBDReply reply; + BlockDriverState *bs; + bool quit; /* For nbd_refresh_filename() */ SocketAddress *saddr; char *export, *tlscredsid; } BDRVNBDState; +static void nbd_recv_coroutines_wake_all(BDRVNBDState *s) +{ + int i; + + for (i = 0; i < MAX_NBD_REQUESTS; i++) { + NBDClientRequest *req = &s->requests[i]; + + if (req->coroutine && req->receiving) { + aio_co_wake(req->coroutine); + } + } +} + +static void nbd_client_detach_aio_context(BlockDriverState *bs) +{ + BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + + qio_channel_detach_aio_context(QIO_CHANNEL(s->ioc)); +} + +static void nbd_client_attach_aio_context_bh(void *opaque) +{ + BlockDriverState *bs = opaque; + BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + + /* + * The node is still drained, so we know the coroutine has yielded in + * nbd_read_eof(), the only place where bs->in_flight can reach 0, or it is + * entered for the first time. Both places are safe for entering the + * coroutine. + */ + qemu_aio_coroutine_enter(bs->aio_context, s->connection_co); + bdrv_dec_in_flight(bs); +} + +static void nbd_client_attach_aio_context(BlockDriverState *bs, + AioContext *new_context) +{ + BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + + qio_channel_attach_aio_context(QIO_CHANNEL(s->ioc), new_context); + + bdrv_inc_in_flight(bs); + + /* + * Need to wait here for the BH to run because the BH must run while the + * node is still drained. + */ + aio_wait_bh_oneshot(new_context, nbd_client_attach_aio_context_bh, bs); +} + + +static void nbd_teardown_connection(BlockDriverState *bs) +{ + BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + + assert(s->ioc); + + /* finish any pending coroutines */ + qio_channel_shutdown(s->ioc, + QIO_CHANNEL_SHUTDOWN_BOTH, + NULL); + BDRV_POLL_WHILE(bs, s->connection_co); + + nbd_client_detach_aio_context(bs); + object_unref(OBJECT(s->sioc)); + s->sioc = NULL; + object_unref(OBJECT(s->ioc)); + s->ioc = NULL; +} + +static coroutine_fn void nbd_connection_entry(void *opaque) +{ + BDRVNBDState *s = opaque; + uint64_t i; + int ret = 0; + Error *local_err = NULL; + + while (!s->quit) { + /* + * The NBD client can only really be considered idle when it has + * yielded from qio_channel_readv_all_eof(), waiting for data. This is + * the point where the additional scheduled coroutine entry happens + * after nbd_client_attach_aio_context(). + * + * Therefore we keep an additional in_flight reference all the time and + * only drop it temporarily here. + */ + assert(s->reply.handle == 0); + ret = nbd_receive_reply(s->bs, s->ioc, &s->reply, &local_err); + + if (local_err) { + trace_nbd_read_reply_entry_fail(ret, error_get_pretty(local_err)); + error_free(local_err); + } + if (ret <= 0) { + break; + } + + /* + * There's no need for a mutex on the receive side, because the + * handler acts as a synchronization point and ensures that only + * one coroutine is called until the reply finishes. + */ + i = HANDLE_TO_INDEX(s, s->reply.handle); + if (i >= MAX_NBD_REQUESTS || + !s->requests[i].coroutine || + !s->requests[i].receiving || + (nbd_reply_is_structured(&s->reply) && !s->info.structured_reply)) + { + break; + } + + /* + * We're woken up again by the request itself. Note that there + * is no race between yielding and reentering connection_co. This + * is because: + * + * - if the request runs on the same AioContext, it is only + * entered after we yield + * + * - if the request runs on a different AioContext, reentering + * connection_co happens through a bottom half, which can only + * run after we yield. + */ + aio_co_wake(s->requests[i].coroutine); + qemu_coroutine_yield(); + } + + s->quit = true; + nbd_recv_coroutines_wake_all(s); + bdrv_dec_in_flight(s->bs); + + s->connection_co = NULL; + aio_wait_kick(); +} + +static int nbd_co_send_request(BlockDriverState *bs, + NBDRequest *request, + QEMUIOVector *qiov) +{ + BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + int rc, i; + + qemu_co_mutex_lock(&s->send_mutex); + while (s->in_flight == MAX_NBD_REQUESTS) { + qemu_co_queue_wait(&s->free_sema, &s->send_mutex); + } + s->in_flight++; + + for (i = 0; i < MAX_NBD_REQUESTS; i++) { + if (s->requests[i].coroutine == NULL) { + break; + } + } + + g_assert(qemu_in_coroutine()); + assert(i < MAX_NBD_REQUESTS); + + s->requests[i].coroutine = qemu_coroutine_self(); + s->requests[i].offset = request->from; + s->requests[i].receiving = false; + + request->handle = INDEX_TO_HANDLE(s, i); + + if (s->quit) { + rc = -EIO; + goto err; + } + assert(s->ioc); + + if (qiov) { + qio_channel_set_cork(s->ioc, true); + rc = nbd_send_request(s->ioc, request); + if (rc >= 0 && !s->quit) { + if (qio_channel_writev_all(s->ioc, qiov->iov, qiov->niov, + NULL) < 0) { + rc = -EIO; + } + } else if (rc >= 0) { + rc = -EIO; + } + qio_channel_set_cork(s->ioc, false); + } else { + rc = nbd_send_request(s->ioc, request); + } + +err: + if (rc < 0) { + s->quit = true; + s->requests[i].coroutine = NULL; + s->in_flight--; + qemu_co_queue_next(&s->free_sema); + } + qemu_co_mutex_unlock(&s->send_mutex); + return rc; +} + +static inline uint16_t payload_advance16(uint8_t **payload) +{ + *payload += 2; + return lduw_be_p(*payload - 2); +} + +static inline uint32_t payload_advance32(uint8_t **payload) +{ + *payload += 4; + return ldl_be_p(*payload - 4); +} + +static inline uint64_t payload_advance64(uint8_t **payload) +{ + *payload += 8; + return ldq_be_p(*payload - 8); +} + +static int nbd_parse_offset_hole_payload(BDRVNBDState *s, + NBDStructuredReplyChunk *chunk, + uint8_t *payload, uint64_t orig_offset, + QEMUIOVector *qiov, Error **errp) +{ + uint64_t offset; + uint32_t hole_size; + + if (chunk->length != sizeof(offset) + sizeof(hole_size)) { + error_setg(errp, "Protocol error: invalid payload for " + "NBD_REPLY_TYPE_OFFSET_HOLE"); + return -EINVAL; + } + + offset = payload_advance64(&payload); + hole_size = payload_advance32(&payload); + + if (!hole_size || offset < orig_offset || hole_size > qiov->size || + offset > orig_offset + qiov->size - hole_size) { + error_setg(errp, "Protocol error: server sent chunk exceeding requested" + " region"); + return -EINVAL; + } + if (s->info.min_block && + !QEMU_IS_ALIGNED(hole_size, s->info.min_block)) { + trace_nbd_structured_read_compliance("hole"); + } + + qemu_iovec_memset(qiov, offset - orig_offset, 0, hole_size); + + return 0; +} + +/* + * nbd_parse_blockstatus_payload + * Based on our request, we expect only one extent in reply, for the + * base:allocation context. + */ +static int nbd_parse_blockstatus_payload(BDRVNBDState *s, + NBDStructuredReplyChunk *chunk, + uint8_t *payload, uint64_t orig_length, + NBDExtent *extent, Error **errp) +{ + uint32_t context_id; + + /* The server succeeded, so it must have sent [at least] one extent */ + if (chunk->length < sizeof(context_id) + sizeof(*extent)) { + error_setg(errp, "Protocol error: invalid payload for " + "NBD_REPLY_TYPE_BLOCK_STATUS"); + return -EINVAL; + } + + context_id = payload_advance32(&payload); + if (s->info.context_id != context_id) { + error_setg(errp, "Protocol error: unexpected context id %d for " + "NBD_REPLY_TYPE_BLOCK_STATUS, when negotiated context " + "id is %d", context_id, + s->info.context_id); + return -EINVAL; + } + + extent->length = payload_advance32(&payload); + extent->flags = payload_advance32(&payload); + + if (extent->length == 0) { + error_setg(errp, "Protocol error: server sent status chunk with " + "zero length"); + return -EINVAL; + } + + /* + * A server sending unaligned block status is in violation of the + * protocol, but as qemu-nbd 3.1 is such a server (at least for + * POSIX files that are not a multiple of 512 bytes, since qemu + * rounds files up to 512-byte multiples but lseek(SEEK_HOLE) + * still sees an implicit hole beyond the real EOF), it's nicer to + * work around the misbehaving server. If the request included + * more than the final unaligned block, truncate it back to an + * aligned result; if the request was only the final block, round + * up to the full block and change the status to fully-allocated + * (always a safe status, even if it loses information). + */ + if (s->info.min_block && !QEMU_IS_ALIGNED(extent->length, + s->info.min_block)) { + trace_nbd_parse_blockstatus_compliance("extent length is unaligned"); + if (extent->length > s->info.min_block) { + extent->length = QEMU_ALIGN_DOWN(extent->length, + s->info.min_block); + } else { + extent->length = s->info.min_block; + extent->flags = 0; + } + } + + /* + * We used NBD_CMD_FLAG_REQ_ONE, so the server should not have + * sent us any more than one extent, nor should it have included + * status beyond our request in that extent. However, it's easy + * enough to ignore the server's noncompliance without killing the + * connection; just ignore trailing extents, and clamp things to + * the length of our request. + */ + if (chunk->length > sizeof(context_id) + sizeof(*extent)) { + trace_nbd_parse_blockstatus_compliance("more than one extent"); + } + if (extent->length > orig_length) { + extent->length = orig_length; + trace_nbd_parse_blockstatus_compliance("extent length too large"); + } + + return 0; +} + +/* + * nbd_parse_error_payload + * on success @errp contains message describing nbd error reply + */ +static int nbd_parse_error_payload(NBDStructuredReplyChunk *chunk, + uint8_t *payload, int *request_ret, + Error **errp) +{ + uint32_t error; + uint16_t message_size; + + assert(chunk->type & (1 << 15)); + + if (chunk->length < sizeof(error) + sizeof(message_size)) { + error_setg(errp, + "Protocol error: invalid payload for structured error"); + return -EINVAL; + } + + error = nbd_errno_to_system_errno(payload_advance32(&payload)); + if (error == 0) { + error_setg(errp, "Protocol error: server sent structured error chunk " + "with error = 0"); + return -EINVAL; + } + + *request_ret = -error; + message_size = payload_advance16(&payload); + + if (message_size > chunk->length - sizeof(error) - sizeof(message_size)) { + error_setg(errp, "Protocol error: server sent structured error chunk " + "with incorrect message size"); + return -EINVAL; + } + + /* TODO: Add a trace point to mention the server complaint */ + + /* TODO handle ERROR_OFFSET */ + + return 0; +} + +static int nbd_co_receive_offset_data_payload(BDRVNBDState *s, + uint64_t orig_offset, + QEMUIOVector *qiov, Error **errp) +{ + QEMUIOVector sub_qiov; + uint64_t offset; + size_t data_size; + int ret; + NBDStructuredReplyChunk *chunk = &s->reply.structured; + + assert(nbd_reply_is_structured(&s->reply)); + + /* The NBD spec requires at least one byte of payload */ + if (chunk->length <= sizeof(offset)) { + error_setg(errp, "Protocol error: invalid payload for " + "NBD_REPLY_TYPE_OFFSET_DATA"); + return -EINVAL; + } + + if (nbd_read64(s->ioc, &offset, "OFFSET_DATA offset", errp) < 0) { + return -EIO; + } + + data_size = chunk->length - sizeof(offset); + assert(data_size); + if (offset < orig_offset || data_size > qiov->size || + offset > orig_offset + qiov->size - data_size) { + error_setg(errp, "Protocol error: server sent chunk exceeding requested" + " region"); + return -EINVAL; + } + if (s->info.min_block && !QEMU_IS_ALIGNED(data_size, s->info.min_block)) { + trace_nbd_structured_read_compliance("data"); + } + + qemu_iovec_init(&sub_qiov, qiov->niov); + qemu_iovec_concat(&sub_qiov, qiov, offset - orig_offset, data_size); + ret = qio_channel_readv_all(s->ioc, sub_qiov.iov, sub_qiov.niov, errp); + qemu_iovec_destroy(&sub_qiov); + + return ret < 0 ? -EIO : 0; +} + +#define NBD_MAX_MALLOC_PAYLOAD 1000 +static coroutine_fn int nbd_co_receive_structured_payload( + BDRVNBDState *s, void **payload, Error **errp) +{ + int ret; + uint32_t len; + + assert(nbd_reply_is_structured(&s->reply)); + + len = s->reply.structured.length; + + if (len == 0) { + return 0; + } + + if (payload == NULL) { + error_setg(errp, "Unexpected structured payload"); + return -EINVAL; + } + + if (len > NBD_MAX_MALLOC_PAYLOAD) { + error_setg(errp, "Payload too large"); + return -EINVAL; + } + + *payload = g_new(char, len); + ret = nbd_read(s->ioc, *payload, len, "structured payload", errp); + if (ret < 0) { + g_free(*payload); + *payload = NULL; + return ret; + } + + return 0; +} + +/* + * nbd_co_do_receive_one_chunk + * for simple reply: + * set request_ret to received reply error + * if qiov is not NULL: read payload to @qiov + * for structured reply chunk: + * if error chunk: read payload, set @request_ret, do not set @payload + * else if offset_data chunk: read payload data to @qiov, do not set @payload + * else: read payload to @payload + * + * If function fails, @errp contains corresponding error message, and the + * connection with the server is suspect. If it returns 0, then the + * transaction succeeded (although @request_ret may be a negative errno + * corresponding to the server's error reply), and errp is unchanged. + */ +static coroutine_fn int nbd_co_do_receive_one_chunk( + BDRVNBDState *s, uint64_t handle, bool only_structured, + int *request_ret, QEMUIOVector *qiov, void **payload, Error **errp) +{ + int ret; + int i = HANDLE_TO_INDEX(s, handle); + void *local_payload = NULL; + NBDStructuredReplyChunk *chunk; + + if (payload) { + *payload = NULL; + } + *request_ret = 0; + + /* Wait until we're woken up by nbd_connection_entry. */ + s->requests[i].receiving = true; + qemu_coroutine_yield(); + s->requests[i].receiving = false; + if (s->quit) { + error_setg(errp, "Connection closed"); + return -EIO; + } + assert(s->ioc); + + assert(s->reply.handle == handle); + + if (nbd_reply_is_simple(&s->reply)) { + if (only_structured) { + error_setg(errp, "Protocol error: simple reply when structured " + "reply chunk was expected"); + return -EINVAL; + } + + *request_ret = -nbd_errno_to_system_errno(s->reply.simple.error); + if (*request_ret < 0 || !qiov) { + return 0; + } + + return qio_channel_readv_all(s->ioc, qiov->iov, qiov->niov, + errp) < 0 ? -EIO : 0; + } + + /* handle structured reply chunk */ + assert(s->info.structured_reply); + chunk = &s->reply.structured; + + if (chunk->type == NBD_REPLY_TYPE_NONE) { + if (!(chunk->flags & NBD_REPLY_FLAG_DONE)) { + error_setg(errp, "Protocol error: NBD_REPLY_TYPE_NONE chunk without" + " NBD_REPLY_FLAG_DONE flag set"); + return -EINVAL; + } + if (chunk->length) { + error_setg(errp, "Protocol error: NBD_REPLY_TYPE_NONE chunk with" + " nonzero length"); + return -EINVAL; + } + return 0; + } + + if (chunk->type == NBD_REPLY_TYPE_OFFSET_DATA) { + if (!qiov) { + error_setg(errp, "Unexpected NBD_REPLY_TYPE_OFFSET_DATA chunk"); + return -EINVAL; + } + + return nbd_co_receive_offset_data_payload(s, s->requests[i].offset, + qiov, errp); + } + + if (nbd_reply_type_is_error(chunk->type)) { + payload = &local_payload; + } + + ret = nbd_co_receive_structured_payload(s, payload, errp); + if (ret < 0) { + return ret; + } + + if (nbd_reply_type_is_error(chunk->type)) { + ret = nbd_parse_error_payload(chunk, local_payload, request_ret, errp); + g_free(local_payload); + return ret; + } + + return 0; +} + +/* + * nbd_co_receive_one_chunk + * Read reply, wake up connection_co and set s->quit if needed. + * Return value is a fatal error code or normal nbd reply error code + */ +static coroutine_fn int nbd_co_receive_one_chunk( + BDRVNBDState *s, uint64_t handle, bool only_structured, + int *request_ret, QEMUIOVector *qiov, NBDReply *reply, void **payload, + Error **errp) +{ + int ret = nbd_co_do_receive_one_chunk(s, handle, only_structured, + request_ret, qiov, payload, errp); + + if (ret < 0) { + s->quit = true; + } else { + /* For assert at loop start in nbd_connection_entry */ + if (reply) { + *reply = s->reply; + } + s->reply.handle = 0; + } + + if (s->connection_co) { + aio_co_wake(s->connection_co); + } + + return ret; +} + +typedef struct NBDReplyChunkIter { + int ret; + int request_ret; + Error *err; + bool done, only_structured; +} NBDReplyChunkIter; + +static void nbd_iter_channel_error(NBDReplyChunkIter *iter, + int ret, Error **local_err) +{ + assert(ret < 0); + + if (!iter->ret) { + iter->ret = ret; + error_propagate(&iter->err, *local_err); + } else { + error_free(*local_err); + } + + *local_err = NULL; +} + +static void nbd_iter_request_error(NBDReplyChunkIter *iter, int ret) +{ + assert(ret < 0); + + if (!iter->request_ret) { + iter->request_ret = ret; + } +} + +/* + * NBD_FOREACH_REPLY_CHUNK + * The pointer stored in @payload requires g_free() to free it. + */ +#define NBD_FOREACH_REPLY_CHUNK(s, iter, handle, structured, \ + qiov, reply, payload) \ + for (iter = (NBDReplyChunkIter) { .only_structured = structured }; \ + nbd_reply_chunk_iter_receive(s, &iter, handle, qiov, reply, payload);) + +/* + * nbd_reply_chunk_iter_receive + * The pointer stored in @payload requires g_free() to free it. + */ +static bool nbd_reply_chunk_iter_receive(BDRVNBDState *s, + NBDReplyChunkIter *iter, + uint64_t handle, + QEMUIOVector *qiov, NBDReply *reply, + void **payload) +{ + int ret, request_ret; + NBDReply local_reply; + NBDStructuredReplyChunk *chunk; + Error *local_err = NULL; + if (s->quit) { + error_setg(&local_err, "Connection closed"); + nbd_iter_channel_error(iter, -EIO, &local_err); + goto break_loop; + } + + if (iter->done) { + /* Previous iteration was last. */ + goto break_loop; + } + + if (reply == NULL) { + reply = &local_reply; + } + + ret = nbd_co_receive_one_chunk(s, handle, iter->only_structured, + &request_ret, qiov, reply, payload, + &local_err); + if (ret < 0) { + nbd_iter_channel_error(iter, ret, &local_err); + } else if (request_ret < 0) { + nbd_iter_request_error(iter, request_ret); + } + + /* Do not execute the body of NBD_FOREACH_REPLY_CHUNK for simple reply. */ + if (nbd_reply_is_simple(reply) || s->quit) { + goto break_loop; + } + + chunk = &reply->structured; + iter->only_structured = true; + + if (chunk->type == NBD_REPLY_TYPE_NONE) { + /* NBD_REPLY_FLAG_DONE is already checked in nbd_co_receive_one_chunk */ + assert(chunk->flags & NBD_REPLY_FLAG_DONE); + goto break_loop; + } + + if (chunk->flags & NBD_REPLY_FLAG_DONE) { + /* This iteration is last. */ + iter->done = true; + } + + /* Execute the loop body */ + return true; + +break_loop: + s->requests[HANDLE_TO_INDEX(s, handle)].coroutine = NULL; + + qemu_co_mutex_lock(&s->send_mutex); + s->in_flight--; + qemu_co_queue_next(&s->free_sema); + qemu_co_mutex_unlock(&s->send_mutex); + + return false; +} + +static int nbd_co_receive_return_code(BDRVNBDState *s, uint64_t handle, + int *request_ret, Error **errp) +{ + NBDReplyChunkIter iter; + + NBD_FOREACH_REPLY_CHUNK(s, iter, handle, false, NULL, NULL, NULL) { + /* nbd_reply_chunk_iter_receive does all the work */ + } + + error_propagate(errp, iter.err); + *request_ret = iter.request_ret; + return iter.ret; +} + +static int nbd_co_receive_cmdread_reply(BDRVNBDState *s, uint64_t handle, + uint64_t offset, QEMUIOVector *qiov, + int *request_ret, Error **errp) +{ + NBDReplyChunkIter iter; + NBDReply reply; + void *payload = NULL; + Error *local_err = NULL; + + NBD_FOREACH_REPLY_CHUNK(s, iter, handle, s->info.structured_reply, + qiov, &reply, &payload) + { + int ret; + NBDStructuredReplyChunk *chunk = &reply.structured; + + assert(nbd_reply_is_structured(&reply)); + + switch (chunk->type) { + case NBD_REPLY_TYPE_OFFSET_DATA: + /* + * special cased in nbd_co_receive_one_chunk, data is already + * in qiov + */ + break; + case NBD_REPLY_TYPE_OFFSET_HOLE: + ret = nbd_parse_offset_hole_payload(s, &reply.structured, payload, + offset, qiov, &local_err); + if (ret < 0) { + s->quit = true; + nbd_iter_channel_error(&iter, ret, &local_err); + } + break; + default: + if (!nbd_reply_type_is_error(chunk->type)) { + /* not allowed reply type */ + s->quit = true; + error_setg(&local_err, + "Unexpected reply type: %d (%s) for CMD_READ", + chunk->type, nbd_reply_type_lookup(chunk->type)); + nbd_iter_channel_error(&iter, -EINVAL, &local_err); + } + } + + g_free(payload); + payload = NULL; + } + + error_propagate(errp, iter.err); + *request_ret = iter.request_ret; + return iter.ret; +} + +static int nbd_co_receive_blockstatus_reply(BDRVNBDState *s, + uint64_t handle, uint64_t length, + NBDExtent *extent, + int *request_ret, Error **errp) +{ + NBDReplyChunkIter iter; + NBDReply reply; + void *payload = NULL; + Error *local_err = NULL; + bool received = false; + + assert(!extent->length); + NBD_FOREACH_REPLY_CHUNK(s, iter, handle, false, NULL, &reply, &payload) { + int ret; + NBDStructuredReplyChunk *chunk = &reply.structured; + + assert(nbd_reply_is_structured(&reply)); + + switch (chunk->type) { + case NBD_REPLY_TYPE_BLOCK_STATUS: + if (received) { + s->quit = true; + error_setg(&local_err, "Several BLOCK_STATUS chunks in reply"); + nbd_iter_channel_error(&iter, -EINVAL, &local_err); + } + received = true; + + ret = nbd_parse_blockstatus_payload(s, &reply.structured, + payload, length, extent, + &local_err); + if (ret < 0) { + s->quit = true; + nbd_iter_channel_error(&iter, ret, &local_err); + } + break; + default: + if (!nbd_reply_type_is_error(chunk->type)) { + s->quit = true; + error_setg(&local_err, + "Unexpected reply type: %d (%s) " + "for CMD_BLOCK_STATUS", + chunk->type, nbd_reply_type_lookup(chunk->type)); + nbd_iter_channel_error(&iter, -EINVAL, &local_err); + } + } + + g_free(payload); + payload = NULL; + } + + if (!extent->length && !iter.request_ret) { + error_setg(&local_err, "Server did not reply with any status extents"); + nbd_iter_channel_error(&iter, -EIO, &local_err); + } + + error_propagate(errp, iter.err); + *request_ret = iter.request_ret; + return iter.ret; +} + +static int nbd_co_request(BlockDriverState *bs, NBDRequest *request, + QEMUIOVector *write_qiov) +{ + int ret, request_ret; + Error *local_err = NULL; + BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + + assert(request->type != NBD_CMD_READ); + if (write_qiov) { + assert(request->type == NBD_CMD_WRITE); + assert(request->len == iov_size(write_qiov->iov, write_qiov->niov)); + } else { + assert(request->type != NBD_CMD_WRITE); + } + ret = nbd_co_send_request(bs, request, write_qiov); + if (ret < 0) { + return ret; + } + + ret = nbd_co_receive_return_code(s, request->handle, + &request_ret, &local_err); + if (local_err) { + trace_nbd_co_request_fail(request->from, request->len, request->handle, + request->flags, request->type, + nbd_cmd_lookup(request->type), + ret, error_get_pretty(local_err)); + error_free(local_err); + } + return ret ? ret : request_ret; +} + +static int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset, + uint64_t bytes, QEMUIOVector *qiov, int flags) +{ + int ret, request_ret; + Error *local_err = NULL; + BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + NBDRequest request = { + .type = NBD_CMD_READ, + .from = offset, + .len = bytes, + }; + + assert(bytes <= NBD_MAX_BUFFER_SIZE); + assert(!flags); + + if (!bytes) { + return 0; + } + /* + * Work around the fact that the block layer doesn't do + * byte-accurate sizing yet - if the read exceeds the server's + * advertised size because the block layer rounded size up, then + * truncate the request to the server and tail-pad with zero. + */ + if (offset >= s->info.size) { + assert(bytes < BDRV_SECTOR_SIZE); + qemu_iovec_memset(qiov, 0, 0, bytes); + return 0; + } + if (offset + bytes > s->info.size) { + uint64_t slop = offset + bytes - s->info.size; + + assert(slop < BDRV_SECTOR_SIZE); + qemu_iovec_memset(qiov, bytes - slop, 0, slop); + request.len -= slop; + } + + ret = nbd_co_send_request(bs, &request, NULL); + if (ret < 0) { + return ret; + } + + ret = nbd_co_receive_cmdread_reply(s, request.handle, offset, qiov, + &request_ret, &local_err); + if (local_err) { + trace_nbd_co_request_fail(request.from, request.len, request.handle, + request.flags, request.type, + nbd_cmd_lookup(request.type), + ret, error_get_pretty(local_err)); + error_free(local_err); + } + return ret ? ret : request_ret; +} + +static int nbd_client_co_pwritev(BlockDriverState *bs, uint64_t offset, + uint64_t bytes, QEMUIOVector *qiov, int flags) +{ + BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + NBDRequest request = { + .type = NBD_CMD_WRITE, + .from = offset, + .len = bytes, + }; + + assert(!(s->info.flags & NBD_FLAG_READ_ONLY)); + if (flags & BDRV_REQ_FUA) { + assert(s->info.flags & NBD_FLAG_SEND_FUA); + request.flags |= NBD_CMD_FLAG_FUA; + } + + assert(bytes <= NBD_MAX_BUFFER_SIZE); + + if (!bytes) { + return 0; + } + return nbd_co_request(bs, &request, qiov); +} + +static int nbd_client_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset, + int bytes, BdrvRequestFlags flags) +{ + BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + NBDRequest request = { + .type = NBD_CMD_WRITE_ZEROES, + .from = offset, + .len = bytes, + }; + + assert(!(s->info.flags & NBD_FLAG_READ_ONLY)); + if (!(s->info.flags & NBD_FLAG_SEND_WRITE_ZEROES)) { + return -ENOTSUP; + } + + if (flags & BDRV_REQ_FUA) { + assert(s->info.flags & NBD_FLAG_SEND_FUA); + request.flags |= NBD_CMD_FLAG_FUA; + } + if (!(flags & BDRV_REQ_MAY_UNMAP)) { + request.flags |= NBD_CMD_FLAG_NO_HOLE; + } + + if (!bytes) { + return 0; + } + return nbd_co_request(bs, &request, NULL); +} + +static int nbd_client_co_flush(BlockDriverState *bs) +{ + BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + NBDRequest request = { .type = NBD_CMD_FLUSH }; + + if (!(s->info.flags & NBD_FLAG_SEND_FLUSH)) { + return 0; + } + + request.from = 0; + request.len = 0; + + return nbd_co_request(bs, &request, NULL); +} + +static int nbd_client_co_pdiscard(BlockDriverState *bs, int64_t offset, + int bytes) +{ + BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + NBDRequest request = { + .type = NBD_CMD_TRIM, + .from = offset, + .len = bytes, + }; + + assert(!(s->info.flags & NBD_FLAG_READ_ONLY)); + if (!(s->info.flags & NBD_FLAG_SEND_TRIM) || !bytes) { + return 0; + } + + return nbd_co_request(bs, &request, NULL); +} + +static int coroutine_fn nbd_client_co_block_status( + BlockDriverState *bs, bool want_zero, int64_t offset, int64_t bytes, + int64_t *pnum, int64_t *map, BlockDriverState **file) +{ + int ret, request_ret; + NBDExtent extent = { 0 }; + BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + Error *local_err = NULL; + + NBDRequest request = { + .type = NBD_CMD_BLOCK_STATUS, + .from = offset, + .len = MIN(MIN_NON_ZERO(QEMU_ALIGN_DOWN(INT_MAX, + bs->bl.request_alignment), + s->info.max_block), + MIN(bytes, s->info.size - offset)), + .flags = NBD_CMD_FLAG_REQ_ONE, + }; + + if (!s->info.base_allocation) { + *pnum = bytes; + *map = offset; + *file = bs; + return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID; + } + + /* + * Work around the fact that the block layer doesn't do + * byte-accurate sizing yet - if the status request exceeds the + * server's advertised size because the block layer rounded size + * up, we truncated the request to the server (above), or are + * called on just the hole. + */ + if (offset >= s->info.size) { + *pnum = bytes; + assert(bytes < BDRV_SECTOR_SIZE); + /* Intentionally don't report offset_valid for the hole */ + return BDRV_BLOCK_ZERO; + } + + if (s->info.min_block) { + assert(QEMU_IS_ALIGNED(request.len, s->info.min_block)); + } + ret = nbd_co_send_request(bs, &request, NULL); + if (ret < 0) { + return ret; + } + + ret = nbd_co_receive_blockstatus_reply(s, request.handle, bytes, + &extent, &request_ret, &local_err); + if (local_err) { + trace_nbd_co_request_fail(request.from, request.len, request.handle, + request.flags, request.type, + nbd_cmd_lookup(request.type), + ret, error_get_pretty(local_err)); + error_free(local_err); + } + if (ret < 0 || request_ret < 0) { + return ret ? ret : request_ret; + } + + assert(extent.length); + *pnum = extent.length; + *map = offset; + *file = bs; + return (extent.flags & NBD_STATE_HOLE ? 0 : BDRV_BLOCK_DATA) | + (extent.flags & NBD_STATE_ZERO ? BDRV_BLOCK_ZERO : 0) | + BDRV_BLOCK_OFFSET_VALID; +} + +static void nbd_client_close(BlockDriverState *bs) +{ + BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + NBDRequest request = { .type = NBD_CMD_DISC }; + + assert(s->ioc); + + nbd_send_request(s->ioc, &request); + + nbd_teardown_connection(bs); +} + +static QIOChannelSocket *nbd_establish_connection(SocketAddress *saddr, + Error **errp) +{ + QIOChannelSocket *sioc; + Error *local_err = NULL; + + sioc = qio_channel_socket_new(); + qio_channel_set_name(QIO_CHANNEL(sioc), "nbd-client"); + + qio_channel_socket_connect_sync(sioc, saddr, &local_err); + if (local_err) { + object_unref(OBJECT(sioc)); + error_propagate(errp, local_err); + return NULL; + } + + qio_channel_set_delay(QIO_CHANNEL(sioc), false); + + return sioc; +} + +static int nbd_client_connect(BlockDriverState *bs, + SocketAddress *saddr, + const char *export, + QCryptoTLSCreds *tlscreds, + const char *hostname, + const char *x_dirty_bitmap, + Error **errp) +{ + BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + int ret; + + /* + * establish TCP connection, return error if it fails + * TODO: Configurable retry-until-timeout behaviour. + */ + QIOChannelSocket *sioc = nbd_establish_connection(saddr, errp); + + if (!sioc) { + return -ECONNREFUSED; + } + + /* NBD handshake */ + trace_nbd_client_connect(export); + qio_channel_set_blocking(QIO_CHANNEL(sioc), true, NULL); + + s->info.request_sizes = true; + s->info.structured_reply = true; + s->info.base_allocation = true; + s->info.x_dirty_bitmap = g_strdup(x_dirty_bitmap); + s->info.name = g_strdup(export ?: ""); + ret = nbd_receive_negotiate(QIO_CHANNEL(sioc), tlscreds, hostname, + &s->ioc, &s->info, errp); + g_free(s->info.x_dirty_bitmap); + g_free(s->info.name); + if (ret < 0) { + object_unref(OBJECT(sioc)); + return ret; + } + if (x_dirty_bitmap && !s->info.base_allocation) { + error_setg(errp, "requested x-dirty-bitmap %s not found", + x_dirty_bitmap); + ret = -EINVAL; + goto fail; + } + if (s->info.flags & NBD_FLAG_READ_ONLY) { + ret = bdrv_apply_auto_read_only(bs, "NBD export is read-only", errp); + if (ret < 0) { + goto fail; + } + } + if (s->info.flags & NBD_FLAG_SEND_FUA) { + bs->supported_write_flags = BDRV_REQ_FUA; + bs->supported_zero_flags |= BDRV_REQ_FUA; + } + if (s->info.flags & NBD_FLAG_SEND_WRITE_ZEROES) { + bs->supported_zero_flags |= BDRV_REQ_MAY_UNMAP; + } + + s->sioc = sioc; + + if (!s->ioc) { + s->ioc = QIO_CHANNEL(sioc); + object_ref(OBJECT(s->ioc)); + } + + /* + * Now that we're connected, set the socket to be non-blocking and + * kick the reply mechanism. + */ + qio_channel_set_blocking(QIO_CHANNEL(sioc), false, NULL); + s->connection_co = qemu_coroutine_create(nbd_connection_entry, s); + bdrv_inc_in_flight(bs); + nbd_client_attach_aio_context(bs, bdrv_get_aio_context(bs)); + + trace_nbd_client_connect_success(export); + + return 0; + + fail: + /* + * We have connected, but must fail for other reasons. The + * connection is still blocking; send NBD_CMD_DISC as a courtesy + * to the server. + */ + { + NBDRequest request = { .type = NBD_CMD_DISC }; + + nbd_send_request(s->ioc ?: QIO_CHANNEL(sioc), &request); + + object_unref(OBJECT(sioc)); + + return ret; + } +} + +static int nbd_client_init(BlockDriverState *bs, + SocketAddress *saddr, + const char *export, + QCryptoTLSCreds *tlscreds, + const char *hostname, + const char *x_dirty_bitmap, + Error **errp) +{ + BDRVNBDState *s = (BDRVNBDState *)bs->opaque; + + s->bs = bs; + qemu_co_mutex_init(&s->send_mutex); + qemu_co_queue_init(&s->free_sema); + + return nbd_client_connect(bs, saddr, export, tlscreds, hostname, + x_dirty_bitmap, errp); +} + static int nbd_parse_uri(const char *filename, QDict *options) { URI *uri; @@ -289,12 +1518,6 @@ done: return saddr; } -NBDClientSession *nbd_get_client_session(BlockDriverState *bs) -{ - BDRVNBDState *s = bs->opaque; - return &s->client; -} - static QCryptoTLSCreds *nbd_get_tls_creds(const char *id, Error **errp) { Object *obj; @@ -433,7 +1656,7 @@ static int nbd_co_flush(BlockDriverState *bs) static void nbd_refresh_limits(BlockDriverState *bs, Error **errp) { - NBDClientSession *s = nbd_get_client_session(bs); + BDRVNBDState *s = (BDRVNBDState *)bs->opaque; uint32_t min = s->info.min_block; uint32_t max = MIN_NON_ZERO(NBD_MAX_BUFFER_SIZE, s->info.max_block); @@ -480,18 +1703,7 @@ static int64_t nbd_getlength(BlockDriverState *bs) { BDRVNBDState *s = bs->opaque; - return s->client.info.size; -} - -static void nbd_detach_aio_context(BlockDriverState *bs) -{ - nbd_client_detach_aio_context(bs); -} - -static void nbd_attach_aio_context(BlockDriverState *bs, - AioContext *new_context) -{ - nbd_client_attach_aio_context(bs, new_context); + return s->info.size; } static void nbd_refresh_filename(BlockDriverState *bs) @@ -559,8 +1771,8 @@ static BlockDriver bdrv_nbd = { .bdrv_co_pdiscard = nbd_client_co_pdiscard, .bdrv_refresh_limits = nbd_refresh_limits, .bdrv_getlength = nbd_getlength, - .bdrv_detach_aio_context = nbd_detach_aio_context, - .bdrv_attach_aio_context = nbd_attach_aio_context, + .bdrv_detach_aio_context = nbd_client_detach_aio_context, + .bdrv_attach_aio_context = nbd_client_attach_aio_context, .bdrv_refresh_filename = nbd_refresh_filename, .bdrv_co_block_status = nbd_client_co_block_status, .bdrv_dirname = nbd_dirname, @@ -581,8 +1793,8 @@ static BlockDriver bdrv_nbd_tcp = { .bdrv_co_pdiscard = nbd_client_co_pdiscard, .bdrv_refresh_limits = nbd_refresh_limits, .bdrv_getlength = nbd_getlength, - .bdrv_detach_aio_context = nbd_detach_aio_context, - .bdrv_attach_aio_context = nbd_attach_aio_context, + .bdrv_detach_aio_context = nbd_client_detach_aio_context, + .bdrv_attach_aio_context = nbd_client_attach_aio_context, .bdrv_refresh_filename = nbd_refresh_filename, .bdrv_co_block_status = nbd_client_co_block_status, .bdrv_dirname = nbd_dirname, @@ -603,8 +1815,8 @@ static BlockDriver bdrv_nbd_unix = { .bdrv_co_pdiscard = nbd_client_co_pdiscard, .bdrv_refresh_limits = nbd_refresh_limits, .bdrv_getlength = nbd_getlength, - .bdrv_detach_aio_context = nbd_detach_aio_context, - .bdrv_attach_aio_context = nbd_attach_aio_context, + .bdrv_detach_aio_context = nbd_client_detach_aio_context, + .bdrv_attach_aio_context = nbd_client_attach_aio_context, .bdrv_refresh_filename = nbd_refresh_filename, .bdrv_co_block_status = nbd_client_co_block_status, .bdrv_dirname = nbd_dirname, diff --git a/block/trace-events b/block/trace-events index eab5149..f6e43ee 100644 --- a/block/trace-events +++ b/block/trace-events @@ -160,11 +160,13 @@ nvme_cmd_map_qiov_iov(void *s, int i, void *page, int pages) "s %p iov[%d] %p pa # iscsi.c iscsi_xcopy(void *src_lun, uint64_t src_off, void *dst_lun, uint64_t dst_off, uint64_t bytes, int ret) "src_lun %p offset %"PRIu64" dst_lun %p offset %"PRIu64" bytes %"PRIu64" ret %d" -# nbd-client.c +# nbd.c nbd_parse_blockstatus_compliance(const char *err) "ignoring extra data from non-compliant server: %s" nbd_structured_read_compliance(const char *type) "server sent non-compliant unaligned read %s chunk" nbd_read_reply_entry_fail(int ret, const char *err) "ret = %d, err: %s" nbd_co_request_fail(uint64_t from, uint32_t len, uint64_t handle, uint16_t flags, uint16_t type, const char *name, int ret, const char *err) "Request failed { .from = %" PRIu64", .len = %" PRIu32 ", .handle = %" PRIu64 ", .flags = 0x%" PRIx16 ", .type = %" PRIu16 " (%s) } ret = %d, err: %s" +nbd_client_connect(const char *export_name) "export '%s'" +nbd_client_connect_success(const char *export_name) "export '%s'" # ssh.c ssh_restart_coroutine(void *co) "co=%p" diff --git a/nbd/server.c b/nbd/server.c index aeca389..10faedc 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -21,15 +21,18 @@ #include "qapi/error.h" #include "trace.h" #include "nbd-internal.h" +#include "qemu/units.h" #define NBD_META_ID_BASE_ALLOCATION 0 #define NBD_META_ID_DIRTY_BITMAP 1 -/* NBD_MAX_BITMAP_EXTENTS: 1 mb of extents data. An empirical +/* + * NBD_MAX_BLOCK_STATUS_EXTENTS: 1 MiB of extents data. An empirical * constant. If an increase is needed, note that the NBD protocol * recommends no larger than 32 mb, so that the client won't consider - * the reply as a denial of service attack. */ -#define NBD_MAX_BITMAP_EXTENTS (0x100000 / 8) + * the reply as a denial of service attack. + */ +#define NBD_MAX_BLOCK_STATUS_EXTENTS (1 * MiB / 8) static int system_errno_to_nbd_errno(int err) { @@ -1960,7 +1963,7 @@ static int nbd_co_send_block_status(NBDClient *client, uint64_t handle, Error **errp) { int ret; - unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS; + unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; NBDExtent *extents = g_new(NBDExtent, nb_extents); uint64_t final_length = length; @@ -2045,7 +2048,7 @@ static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle, uint32_t context_id, Error **errp) { int ret; - unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BITMAP_EXTENTS; + unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; NBDExtent *extents = g_new(NBDExtent, nb_extents); uint64_t final_length = length; @@ -61,6 +61,7 @@ #define QEMU_NBD_OPT_IMAGE_OPTS 262 #define QEMU_NBD_OPT_FORK 263 #define QEMU_NBD_OPT_TLSAUTHZ 264 +#define QEMU_NBD_OPT_PID_FILE 265 #define MBR_SIZE 512 @@ -113,6 +114,7 @@ static void usage(const char *name) " specify tracing options\n" " --fork fork off the server process and exit the parent\n" " once the server is running\n" +" --pid-file=PATH store the server's process ID in the given file\n" #if HAVE_NBD_DEVICE "\n" "Kernel NBD client support:\n" @@ -641,6 +643,7 @@ int main(int argc, char **argv) { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS }, { "trace", required_argument, NULL, 'T' }, { "fork", no_argument, NULL, QEMU_NBD_OPT_FORK }, + { "pid-file", required_argument, NULL, QEMU_NBD_OPT_PID_FILE }, { NULL, 0, NULL, 0 } }; int ch; @@ -667,6 +670,7 @@ int main(int argc, char **argv) bool list = false; int old_stderr = -1; unsigned socket_activation; + const char *pid_file_name = NULL; /* The client thread uses SIGTERM to interrupt the server. A signal * handler ensures that "qemu-nbd -v -c" exits with a nice status code. @@ -866,6 +870,9 @@ int main(int argc, char **argv) case 'L': list = true; break; + case QEMU_NBD_OPT_PID_FILE: + pid_file_name = optarg; + break; } } @@ -997,10 +1004,11 @@ int main(int argc, char **argv) exit(EXIT_FAILURE); } else if (pid == 0) { close(stderr_fd[0]); + + old_stderr = dup(STDERR_FILENO); ret = qemu_daemon(1, 0); /* Temporarily redirect stderr to the parent's pipe... */ - old_stderr = dup(STDERR_FILENO); dup2(stderr_fd[1], STDERR_FILENO); if (ret < 0) { error_report("Failed to daemonize: %s", strerror(errno)); @@ -1186,6 +1194,10 @@ int main(int argc, char **argv) nbd_update_server_watch(); + if (pid_file_name) { + qemu_write_pidfile(pid_file_name, &error_fatal); + } + /* now when the initialization is (almost) complete, chdir("/") * to free any busy filesystems */ if (chdir("/") < 0) { diff --git a/qemu-nbd.texi b/qemu-nbd.texi index de342c7..7f55657 100644 --- a/qemu-nbd.texi +++ b/qemu-nbd.texi @@ -117,6 +117,8 @@ option; or provide the credentials needed for connecting as a client in list mode. @item --fork Fork off the server process and exit the parent once the server is running. +@item --pid-file=PATH +Store the server's process ID in the given file. @item --tls-authz=ID Specify the ID of a qauthz object previously created with the --object option. This will be used to authorize connecting users diff --git a/tests/qemu-iotests/147 b/tests/qemu-iotests/147 index 8251327..2d84fdd 100755 --- a/tests/qemu-iotests/147 +++ b/tests/qemu-iotests/147 @@ -24,7 +24,7 @@ import socket import stat import time import iotests -from iotests import cachemode, imgfmt, qemu_img, qemu_nbd, qemu_nbd_pipe +from iotests import cachemode, imgfmt, qemu_img, qemu_nbd, qemu_nbd_early_pipe NBD_PORT_START = 32768 NBD_PORT_END = NBD_PORT_START + 1024 @@ -93,7 +93,7 @@ class QemuNBD(NBDBlockdevAddBase): pass def _try_server_up(self, *args): - status, msg = qemu_nbd_pipe('-f', imgfmt, test_img, *args) + status, msg = qemu_nbd_early_pipe('-f', imgfmt, test_img, *args) if status == 0: return True if 'Address already in use' in msg: diff --git a/tests/qemu-iotests/233 b/tests/qemu-iotests/233 index 057cad2..a5c17c3 100755 --- a/tests/qemu-iotests/233 +++ b/tests/qemu-iotests/233 @@ -49,7 +49,6 @@ _supported_proto file # If porting to non-Linux, consider using socat instead of ss in common.nbd _require_command QEMU_NBD -nbd_server_set_tcp_port tls_x509_init echo diff --git a/tests/qemu-iotests/common.nbd b/tests/qemu-iotests/common.nbd index 25fc9ff..24b01b6 100644 --- a/tests/qemu-iotests/common.nbd +++ b/tests/qemu-iotests/common.nbd @@ -22,6 +22,11 @@ nbd_unix_socket="${TEST_DIR}/qemu-nbd.sock" nbd_tcp_addr="127.0.0.1" nbd_pid_file="${TEST_DIR}/qemu-nbd.pid" +nbd_stderr_fifo="${TEST_DIR}/qemu-nbd.fifo" + +# If bash version is >= 4.1, this will be overwritten by a dynamically +# assigned file descriptor value. +nbd_fifo_fd=10 nbd_server_stop() { @@ -33,77 +38,62 @@ nbd_server_stop() kill "$NBD_PID" fi fi - rm -f "$nbd_unix_socket" -} - -nbd_server_wait_for_unix_socket() -{ - pid=$1 - - for ((i = 0; i < 300; i++)) - do - if [ -r "$nbd_unix_socket" ]; then - return - fi - kill -s 0 $pid 2>/dev/null - if test $? != 0 - then - echo "qemu-nbd unexpectedly quit" - exit 1 - fi - sleep 0.1 - done - echo "Failed in check of unix socket created by qemu-nbd" - exit 1 + rm -f "$nbd_unix_socket" "$nbd_stderr_fifo" } nbd_server_start_unix_socket() { nbd_server_stop - $QEMU_NBD -v -t -k "$nbd_unix_socket" "$@" & - nbd_server_wait_for_unix_socket $! + $QEMU_NBD -v -t -k "$nbd_unix_socket" --fork "$@" } -nbd_server_set_tcp_port() +nbd_server_start_tcp_socket() { - (ss --help) >/dev/null 2>&1 || _notrun "ss utility not found, skipping test" + nbd_server_stop + mkfifo "$nbd_stderr_fifo" for ((port = 10809; port <= 10909; port++)) do - if ! ss -tln | grep -sqE ":$port\b"; then + # Redirect stderr to FIFO, so we can later decide whether we + # want to read it or to redirect it to our stderr, depending + # on whether the command fails or not + $QEMU_NBD -v -t -b $nbd_tcp_addr -p $port --fork "$@" \ + 2> "$nbd_stderr_fifo" & + + # Taken from common.qemu + if [[ "${BASH_VERSINFO[0]}" -ge "5" || + ("${BASH_VERSINFO[0]}" -ge "4" && "${BASH_VERSINFO[1]}" -ge "1") ]] + then + exec {nbd_fifo_fd}<"$nbd_stderr_fifo" + else + let _nbd_fifo_fd++ + eval "exec ${_nbd_fifo_fd}<'$nbd_stderr_fifo'" + fi + wait $! + + if test $? == 0 + then + # Success, redirect qemu-nbd's stderr to our stderr nbd_tcp_port=$port + (cat <&$nbd_fifo_fd >&2) & + eval "exec $nbd_fifo_fd>&-" return fi - done - echo "Cannot find free TCP port for nbd in range 10809-10909" - exit 1 -} - -nbd_server_wait_for_tcp_socket() -{ - pid=$1 + # Failure, read the output + output=$(cat <&$nbd_fifo_fd) + eval "exec $nbd_fifo_fd>&-" - for ((i = 0; i < 300; i++)) - do - if ss -tln | grep -sqE ":$nbd_tcp_port\b"; then - return - fi - kill -s 0 $pid 2>/dev/null - if test $? != 0 + if ! echo "$output" | grep -q "Address already in use" then - echo "qemu-nbd unexpectedly quit" + # Unknown error, print it + echo "$output" >&2 + rm -f "$nbd_stderr_fifo" exit 1 fi - sleep 0.1 done - echo "Failed in check of TCP socket created by qemu-nbd" - exit 1 -} -nbd_server_start_tcp_socket() -{ - nbd_server_stop - $QEMU_NBD -v -t -b $nbd_tcp_addr -p $nbd_tcp_port "$@" & - nbd_server_wait_for_tcp_socket $! + echo "Cannot find free TCP port for nbd in range 10809-10909" + rm -f "$nbd_stderr_fifo" + exit 1 } diff --git a/tests/qemu-iotests/common.rc b/tests/qemu-iotests/common.rc index 93f8738..5502c3d 100644 --- a/tests/qemu-iotests/common.rc +++ b/tests/qemu-iotests/common.rc @@ -105,10 +105,8 @@ _qemu_io_wrapper() _qemu_nbd_wrapper() { - ( - echo $BASHPID > "${QEMU_TEST_DIR}/qemu-nbd.pid" - exec "$QEMU_NBD_PROG" $QEMU_NBD_OPTIONS "$@" - ) + "$QEMU_NBD_PROG" --pid-file="${QEMU_TEST_DIR}/qemu-nbd.pid" \ + $QEMU_NBD_OPTIONS "$@" } _qemu_vxhs_wrapper() diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py index 6bcddd8..f11482f 100644 --- a/tests/qemu-iotests/iotests.py +++ b/tests/qemu-iotests/iotests.py @@ -209,9 +209,9 @@ def qemu_nbd(*args): '''Run qemu-nbd in daemon mode and return the parent's exit code''' return subprocess.call(qemu_nbd_args + ['--fork'] + list(args)) -def qemu_nbd_pipe(*args): +def qemu_nbd_early_pipe(*args): '''Run qemu-nbd in daemon mode and return both the parent's exit code - and its output''' + and its output in case of an error''' subp = subprocess.Popen(qemu_nbd_args + ['--fork'] + list(args), stdout=subprocess.PIPE, stderr=subprocess.STDOUT, @@ -221,7 +221,10 @@ def qemu_nbd_pipe(*args): sys.stderr.write('qemu-nbd received signal %i: %s\n' % (-exitcode, ' '.join(qemu_nbd_args + ['--fork'] + list(args)))) - return exitcode, subp.communicate()[0] + if exitcode == 0: + return exitcode, '' + else: + return exitcode, subp.communicate()[0] def compare_images(img1, img2, fmt1=imgfmt, fmt2=imgfmt): '''Return True if two image files are identical''' |