Skip to content

Commit

Permalink
Browse files Browse the repository at this point in the history
nbd/server: Refactor to pass full request around 
Part of NBD's 64-bit headers extension involves passing the client's
requested offset back as part of the reply header (one reason it
stated for this change: converting absolute offsets stored in
NBD_REPLY_TYPE_OFFSET_DATA to relative offsets within the buffer is
easier if the absolute offset of the buffer is also available).  This
is a refactoring patch to pass the full request around the reply
stack, rather than just the handle, so that later patches can then
access request->from when extended headers are active.  Meanwhile,
this patch enables us to now assert that simple replies are only
attempted when appropriate, and otherwise has no semantic change.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Message-ID: <20230608135653.2918540-5-eblake@redhat.com>
  • Loading branch information
@ebblake
ebblake committed Jul 19, 2023
1 parent a7c8ed3 commit 66d4f4f
Showing 1 changed file with 59 additions and 55 deletions.
114 changes: 59 additions & 55 deletions nbd/server.c
View file
Expand Up @@ -1893,7 +1893,7 @@ static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error,
}

static int coroutine_fn nbd_co_send_simple_reply(NBDClient *client,
uint64_t handle,
NBDRequest *request,
uint32_t error,
void *data,
size_t len,
Expand All @@ -1907,9 +1907,10 @@ static int coroutine_fn nbd_co_send_simple_reply(NBDClient *client,
};

assert(!len || !nbd_err);
trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err),
len);
set_be_simple_reply(&reply, nbd_err, handle);
assert(!client->structured_reply || request->type != NBD_CMD_READ);
trace_nbd_co_send_simple_reply(request->handle, nbd_err,
nbd_err_lookup(nbd_err), len);
set_be_simple_reply(&reply, nbd_err, request->handle);

return nbd_co_send_iov(client, iov, 2, errp);
}
Expand All @@ -1924,7 +1925,7 @@ static int coroutine_fn nbd_co_send_simple_reply(NBDClient *client,
*/
static inline void set_be_chunk(NBDClient *client, struct iovec *iov,
size_t niov, uint16_t flags, uint16_t type,
uint64_t handle)
NBDRequest *request)
{
/* TODO - handle structured vs. extended replies */
NBDStructuredReplyChunk *chunk = iov->iov_base;
Expand All @@ -1939,28 +1940,28 @@ static inline void set_be_chunk(NBDClient *client, struct iovec *iov,
stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC);
stw_be_p(&chunk->flags, flags);
stw_be_p(&chunk->type, type);
stq_be_p(&chunk->handle, handle);
stq_be_p(&chunk->handle, request->handle);
stl_be_p(&chunk->length, length);
}

static int coroutine_fn nbd_co_send_chunk_done(NBDClient *client,
uint64_t handle,
NBDRequest *request,
Error **errp)
{
NBDReply hdr;
struct iovec iov[] = {
{.iov_base = &hdr},
};

trace_nbd_co_send_chunk_done(handle);
trace_nbd_co_send_chunk_done(request->handle);
set_be_chunk(client, iov, 1, NBD_REPLY_FLAG_DONE,
NBD_REPLY_TYPE_NONE, handle);
NBD_REPLY_TYPE_NONE, request);

return nbd_co_send_iov(client, iov, 1, errp);
}

static int coroutine_fn nbd_co_send_chunk_read(NBDClient *client,
uint64_t handle,
NBDRequest *request,
uint64_t offset,
void *data,
size_t size,
Expand All @@ -1976,16 +1977,16 @@ static int coroutine_fn nbd_co_send_chunk_read(NBDClient *client,
};

assert(size);
trace_nbd_co_send_chunk_read(handle, offset, data, size);
trace_nbd_co_send_chunk_read(request->handle, offset, data, size);
set_be_chunk(client, iov, 3, final ? NBD_REPLY_FLAG_DONE : 0,
NBD_REPLY_TYPE_OFFSET_DATA, handle);
NBD_REPLY_TYPE_OFFSET_DATA, request);
stq_be_p(&chunk.offset, offset);

return nbd_co_send_iov(client, iov, 3, errp);
}

/*ebb*/
static int coroutine_fn nbd_co_send_chunk_error(NBDClient *client,
uint64_t handle,
NBDRequest *request,
uint32_t error,
const char *msg,
Error **errp)
Expand All @@ -2000,10 +2001,10 @@ static int coroutine_fn nbd_co_send_chunk_error(NBDClient *client,
};

assert(nbd_err);
trace_nbd_co_send_chunk_error(handle, nbd_err,
trace_nbd_co_send_chunk_error(request->handle, nbd_err,
nbd_err_lookup(nbd_err), msg ? msg : "");
set_be_chunk(client, iov, 3, NBD_REPLY_FLAG_DONE,
NBD_REPLY_TYPE_ERROR, handle);
NBD_REPLY_TYPE_ERROR, request);
stl_be_p(&chunk.error, nbd_err);
stw_be_p(&chunk.message_length, iov[2].iov_len);

Expand All @@ -2015,7 +2016,7 @@ static int coroutine_fn nbd_co_send_chunk_error(NBDClient *client,
* reported to the client, at which point this function succeeds.
*/
static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,
uint64_t handle,
NBDRequest *request,
uint64_t offset,
uint8_t *data,
size_t size,
Expand All @@ -2037,7 +2038,7 @@ static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,
char *msg = g_strdup_printf("unable to check for holes: %s",
strerror(-status));

ret = nbd_co_send_chunk_error(client, handle, -status, msg, errp);
ret = nbd_co_send_chunk_error(client, request, -status, msg, errp);
g_free(msg);
return ret;
}
Expand All @@ -2051,10 +2052,11 @@ static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,
{.iov_base = &chunk, .iov_len = sizeof(chunk)},
};

trace_nbd_co_send_chunk_read_hole(handle, offset + progress, pnum);
trace_nbd_co_send_chunk_read_hole(request->handle,
offset + progress, pnum);
set_be_chunk(client, iov, 2,
final ? NBD_REPLY_FLAG_DONE : 0,
NBD_REPLY_TYPE_OFFSET_HOLE, handle);
NBD_REPLY_TYPE_OFFSET_HOLE, request);
stq_be_p(&chunk.offset, offset + progress);
stl_be_p(&chunk.length, pnum);
ret = nbd_co_send_iov(client, iov, 2, errp);
Expand All @@ -2065,7 +2067,7 @@ static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,
error_setg_errno(errp, -ret, "reading from file failed");
break;
}
ret = nbd_co_send_chunk_read(client, handle, offset + progress,
ret = nbd_co_send_chunk_read(client, request, offset + progress,
data + progress, pnum, final, errp);
}

Expand Down Expand Up @@ -2219,7 +2221,7 @@ static int coroutine_fn blockalloc_to_extents(BlockBackend *blk,
* @last controls whether NBD_REPLY_FLAG_DONE is sent.
*/
static int coroutine_fn
nbd_co_send_extents(NBDClient *client, uint64_t handle, NBDExtentArray *ea,
nbd_co_send_extents(NBDClient *client, NBDRequest *request, NBDExtentArray *ea,
bool last, uint32_t context_id, Error **errp)
{
NBDReply hdr;
Expand All @@ -2232,18 +2234,18 @@ nbd_co_send_extents(NBDClient *client, uint64_t handle, NBDExtentArray *ea,

nbd_extent_array_convert_to_be(ea);

trace_nbd_co_send_extents(handle, ea->count, context_id, ea->total_length,
last);
trace_nbd_co_send_extents(request->handle, ea->count, context_id,
ea->total_length, last);
set_be_chunk(client, iov, 3, last ? NBD_REPLY_FLAG_DONE : 0,
NBD_REPLY_TYPE_BLOCK_STATUS, handle);
NBD_REPLY_TYPE_BLOCK_STATUS, request);
stl_be_p(&chunk.context_id, context_id);

return nbd_co_send_iov(client, iov, 3, errp);
}

/* Get block status from the exported device and send it to the client */
static int
coroutine_fn nbd_co_send_block_status(NBDClient *client, uint64_t handle,
coroutine_fn nbd_co_send_block_status(NBDClient *client, NBDRequest *request,
BlockBackend *blk, uint64_t offset,
uint32_t length, bool dont_fragment,
bool last, uint32_t context_id,
Expand All @@ -2259,11 +2261,11 @@ coroutine_fn nbd_co_send_block_status(NBDClient *client, uint64_t handle,
ret = blockalloc_to_extents(blk, offset, length, ea);
}
if (ret < 0) {
return nbd_co_send_chunk_error(client, handle, -ret,
return nbd_co_send_chunk_error(client, request, -ret,
"can't get block status", errp);
}

return nbd_co_send_extents(client, handle, ea, last, context_id, errp);
return nbd_co_send_extents(client, request, ea, last, context_id, errp);
}

/* Populate @ea from a dirty bitmap. */
Expand Down Expand Up @@ -2298,17 +2300,20 @@ static void bitmap_to_extents(BdrvDirtyBitmap *bitmap,
bdrv_dirty_bitmap_unlock(bitmap);
}

static int coroutine_fn nbd_co_send_bitmap(NBDClient *client, uint64_t handle,
BdrvDirtyBitmap *bitmap, uint64_t offset,
uint32_t length, bool dont_fragment, bool last,
uint32_t context_id, Error **errp)
static int coroutine_fn nbd_co_send_bitmap(NBDClient *client,
NBDRequest *request,
BdrvDirtyBitmap *bitmap,
uint64_t offset,
uint32_t length, bool dont_fragment,
bool last, uint32_t context_id,
Error **errp)
{
unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS;
g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents);

bitmap_to_extents(bitmap, offset, length, ea);

return nbd_co_send_extents(client, handle, ea, last, context_id, errp);
return nbd_co_send_extents(client, request, ea, last, context_id, errp);
}

/* nbd_co_receive_request
Expand Down Expand Up @@ -2426,15 +2431,15 @@ static int coroutine_fn nbd_co_receive_request(NBDRequestData *req, NBDRequest *
* Returns 0 if connection is still live, -errno on failure to talk to client
*/
static coroutine_fn int nbd_send_generic_reply(NBDClient *client,
uint64_t handle,
NBDRequest *request,
int ret,
const char *error_msg,
Error **errp)
{
if (client->structured_reply && ret < 0) {
return nbd_co_send_chunk_error(client, handle, -ret, error_msg, errp);
return nbd_co_send_chunk_error(client, request, -ret, error_msg, errp);
} else {
return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0,
return nbd_co_send_simple_reply(client, request, ret < 0 ? -ret : 0,
NULL, 0, errp);
}
}
Expand All @@ -2454,34 +2459,33 @@ static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request,
if (request->flags & NBD_CMD_FLAG_FUA) {
ret = blk_co_flush(exp->common.blk);
if (ret < 0) {
return nbd_send_generic_reply(client, request->handle, ret,
return nbd_send_generic_reply(client, request, ret,
"flush failed", errp);
}
}

if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) &&
request->len)
{
return nbd_co_send_sparse_read(client, request->handle, request->from,
return nbd_co_send_sparse_read(client, request, request->from,
data, request->len, errp);
}

ret = blk_co_pread(exp->common.blk, request->from, request->len, data, 0);
if (ret < 0) {
return nbd_send_generic_reply(client, request->handle, ret,
return nbd_send_generic_reply(client, request, ret,
"reading from file failed", errp);
}

if (client->structured_reply) {
if (request->len) {
return nbd_co_send_chunk_read(client, request->handle,
request->from, data,
return nbd_co_send_chunk_read(client, request, request->from, data,
request->len, true, errp);
} else {
return nbd_co_send_chunk_done(client, request->handle, errp);
return nbd_co_send_chunk_done(client, request, errp);
}
} else {
return nbd_co_send_simple_reply(client, request->handle, 0,
return nbd_co_send_simple_reply(client, request, 0,
data, request->len, errp);
}
}
Expand All @@ -2504,7 +2508,7 @@ static coroutine_fn int nbd_do_cmd_cache(NBDClient *client, NBDRequest *request,
ret = blk_co_preadv(exp->common.blk, request->from, request->len,
NULL, BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH);

return nbd_send_generic_reply(client, request->handle, ret,
return nbd_send_generic_reply(client, request, ret,
"caching data failed", errp);
}

Expand Down Expand Up @@ -2535,7 +2539,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
}
ret = blk_co_pwrite(exp->common.blk, request->from, request->len, data,
flags);
return nbd_send_generic_reply(client, request->handle, ret,
return nbd_send_generic_reply(client, request, ret,
"writing to file failed", errp);

case NBD_CMD_WRITE_ZEROES:
Expand All @@ -2551,7 +2555,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
}
ret = blk_co_pwrite_zeroes(exp->common.blk, request->from, request->len,
flags);
return nbd_send_generic_reply(client, request->handle, ret,
return nbd_send_generic_reply(client, request, ret,
"writing to file failed", errp);

case NBD_CMD_DISC:
Expand All @@ -2560,28 +2564,28 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,

case NBD_CMD_FLUSH:
ret = blk_co_flush(exp->common.blk);
return nbd_send_generic_reply(client, request->handle, ret,
return nbd_send_generic_reply(client, request, ret,
"flush failed", errp);

case NBD_CMD_TRIM:
ret = blk_co_pdiscard(exp->common.blk, request->from, request->len);
if (ret >= 0 && request->flags & NBD_CMD_FLAG_FUA) {
ret = blk_co_flush(exp->common.blk);
}
return nbd_send_generic_reply(client, request->handle, ret,
return nbd_send_generic_reply(client, request, ret,
"discard failed", errp);

case NBD_CMD_BLOCK_STATUS:
if (!request->len) {
return nbd_send_generic_reply(client, request->handle, -EINVAL,
return nbd_send_generic_reply(client, request, -EINVAL,
"need non-zero length", errp);
}
if (client->export_meta.count) {
bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE;
int contexts_remaining = client->export_meta.count;

if (client->export_meta.base_allocation) {
ret = nbd_co_send_block_status(client, request->handle,
ret = nbd_co_send_block_status(client, request,
exp->common.blk,
request->from,
request->len, dont_fragment,
Expand All @@ -2594,7 +2598,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
}

if (client->export_meta.allocation_depth) {
ret = nbd_co_send_block_status(client, request->handle,
ret = nbd_co_send_block_status(client, request,
exp->common.blk,
request->from, request->len,
dont_fragment,
Expand All @@ -2610,7 +2614,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
if (!client->export_meta.bitmaps[i]) {
continue;
}
ret = nbd_co_send_bitmap(client, request->handle,
ret = nbd_co_send_bitmap(client, request,
client->exp->export_bitmaps[i],
request->from, request->len,
dont_fragment, !--contexts_remaining,
Expand All @@ -2624,15 +2628,15 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,

return 0;
} else {
return nbd_send_generic_reply(client, request->handle, -EINVAL,
return nbd_send_generic_reply(client, request, -EINVAL,
"CMD_BLOCK_STATUS not negotiated",
errp);
}

default:
msg = g_strdup_printf("invalid request type (%" PRIu32 ") received",
request->type);
ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg,
ret = nbd_send_generic_reply(client, request, -EINVAL, msg,
errp);
g_free(msg);
return ret;
Expand Down Expand Up @@ -2695,7 +2699,7 @@ static coroutine_fn void nbd_trip(void *opaque)
Error *export_err = local_err;

local_err = NULL;
ret = nbd_send_generic_reply(client, request.handle, -EINVAL,
ret = nbd_send_generic_reply(client, &request, -EINVAL,
error_get_pretty(export_err), &local_err);
error_free(export_err);
} else {
Expand Down

0 comments on commit 66d4f4f

Please sign in to comment.