From a7c18670b429cc5e9c5e6a25cc401dc93086f1a7 Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Mon, 25 Sep 2023 14:22:38 -0500 Subject: [PATCH] nbd/client: Accept 64-bit block status chunks Once extended mode is enabled, we need to accept 64-bit status replies (even for replies that don't exceed a 32-bit length). It is easier to normalize narrow replies into wide format so that the rest of our code only has to handle one width. Although a server is non-compliant if it sends a 64-bit reply in compact mode, or a 32-bit reply in extended mode, it is still easy enough to tolerate these mismatches. In normal execution, we are only requesting "base:allocation" which never exceeds 32 bits for flag values. But during testing with x-dirty-bitmap, we can force qemu to connect to some other context that might have 64-bit status bit; however, we ignore those upper bits (other than mapping qemu:allocation-depth into something that 'qemu-img map --output=json' can expose), and since that only affects testing, we really don't bother with checking whether more than the two least-significant bits are set. Signed-off-by: Eric Blake Reviewed-by: Vladimir Sementsov-Ogievskiy Message-ID: <20230925192229.3186470-22-eblake@redhat.com> --- block/nbd.c | 49 ++++++++++++++++++++++++++++++++-------------- block/trace-events | 1 + 2 files changed, 35 insertions(+), 15 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index 7646143041..52ebc8b2f5 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -615,13 +615,17 @@ static int nbd_parse_offset_hole_payload(BDRVNBDState *s, */ static int nbd_parse_blockstatus_payload(BDRVNBDState *s, NBDStructuredReplyChunk *chunk, - uint8_t *payload, uint64_t orig_length, - NBDExtent32 *extent, Error **errp) + uint8_t *payload, bool wide, + uint64_t orig_length, + NBDExtent64 *extent, Error **errp) { uint32_t context_id; + uint32_t count; + size_t ext_len = wide ? sizeof(*extent) : sizeof(NBDExtent32); + size_t pay_len = sizeof(context_id) + wide * sizeof(count) + ext_len; /* The server succeeded, so it must have sent [at least] one extent */ - if (chunk->length < sizeof(context_id) + sizeof(*extent)) { + if (chunk->length < pay_len) { error_setg(errp, "Protocol error: invalid payload for " "NBD_REPLY_TYPE_BLOCK_STATUS"); return -EINVAL; @@ -636,8 +640,15 @@ static int nbd_parse_blockstatus_payload(BDRVNBDState *s, return -EINVAL; } - extent->length = payload_advance32(&payload); - extent->flags = payload_advance32(&payload); + if (wide) { + count = payload_advance32(&payload); + extent->length = payload_advance64(&payload); + extent->flags = payload_advance64(&payload); + } else { + count = 0; + extent->length = payload_advance32(&payload); + extent->flags = payload_advance32(&payload); + } if (extent->length == 0) { error_setg(errp, "Protocol error: server sent status chunk with " @@ -658,7 +669,7 @@ static int nbd_parse_blockstatus_payload(BDRVNBDState *s, * (always a safe status, even if it loses information). */ if (s->info.min_block && !QEMU_IS_ALIGNED(extent->length, - s->info.min_block)) { + 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, @@ -672,13 +683,15 @@ static int nbd_parse_blockstatus_payload(BDRVNBDState *s, /* * 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 + * status beyond our request in that extent. Furthermore, a wide + * server should have replied with an accurate count (we left + * count at 0 for a narrow server). 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 (count != wide || chunk->length > pay_len) { + trace_nbd_parse_blockstatus_compliance("unexpected extent count"); } if (extent->length > orig_length) { extent->length = orig_length; @@ -1124,7 +1137,7 @@ nbd_co_receive_cmdread_reply(BDRVNBDState *s, uint64_t cookie, static int coroutine_fn nbd_co_receive_blockstatus_reply(BDRVNBDState *s, uint64_t cookie, - uint64_t length, NBDExtent32 *extent, + uint64_t length, NBDExtent64 *extent, int *request_ret, Error **errp) { NBDReplyChunkIter iter; @@ -1137,11 +1150,17 @@ nbd_co_receive_blockstatus_reply(BDRVNBDState *s, uint64_t cookie, NBD_FOREACH_REPLY_CHUNK(s, iter, cookie, false, NULL, &reply, &payload) { int ret; NBDStructuredReplyChunk *chunk = &reply.structured; + bool wide; assert(nbd_reply_is_structured(&reply)); switch (chunk->type) { + case NBD_REPLY_TYPE_BLOCK_STATUS_EXT: case NBD_REPLY_TYPE_BLOCK_STATUS: + wide = chunk->type == NBD_REPLY_TYPE_BLOCK_STATUS_EXT; + if ((s->info.mode >= NBD_MODE_EXTENDED) != wide) { + trace_nbd_extended_headers_compliance("block_status"); + } if (received) { nbd_channel_error(s, -EINVAL); error_setg(&local_err, "Several BLOCK_STATUS chunks in reply"); @@ -1149,9 +1168,9 @@ nbd_co_receive_blockstatus_reply(BDRVNBDState *s, uint64_t cookie, } received = true; - ret = nbd_parse_blockstatus_payload(s, &reply.structured, - payload, length, extent, - &local_err); + ret = nbd_parse_blockstatus_payload( + s, &reply.structured, payload, wide, + length, extent, &local_err); if (ret < 0) { nbd_channel_error(s, ret); nbd_iter_channel_error(&iter, ret, &local_err); @@ -1381,7 +1400,7 @@ static int coroutine_fn GRAPH_RDLOCK nbd_client_co_block_status( int64_t *pnum, int64_t *map, BlockDriverState **file) { int ret, request_ret; - NBDExtent32 extent = { 0 }; + NBDExtent64 extent = { 0 }; BDRVNBDState *s = (BDRVNBDState *)bs->opaque; Error *local_err = NULL; diff --git a/block/trace-events b/block/trace-events index 925aa554bb..8e789e1f12 100644 --- a/block/trace-events +++ b/block/trace-events @@ -166,6 +166,7 @@ iscsi_xcopy(void *src_lun, uint64_t src_off, void *dst_lun, uint64_t dst_off, ui # 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_extended_headers_compliance(const char *type) "server sent non-compliant %s chunk not matching choice of extended headers" nbd_read_reply_entry_fail(int ret, const char *err) "ret = %d, err: %s" nbd_co_request_fail(uint64_t from, uint64_t len, uint64_t handle, uint16_t flags, uint16_t type, const char *name, int ret, const char *err) "Request failed { .from = %" PRIu64", .len = %" PRIu64 ", .handle = %" PRIu64 ", .flags = 0x%" PRIx16 ", .type = %" PRIu16 " (%s) } ret = %d, err: %s" nbd_client_handshake(const char *export_name) "export '%s'"