diff options
Diffstat (limited to 'block/nbd-client.c')
| -rw-r--r-- | block/nbd-client.c | 30 |
1 files changed, 26 insertions, 4 deletions
diff --git a/block/nbd-client.c b/block/nbd-client.c index a3b70d1400..150af9cc46 100644 --- a/block/nbd-client.c +++ b/block/nbd-client.c @@ -269,15 +269,37 @@ static int nbd_parse_blockstatus_payload(NBDClientSession *client, extent->length = payload_advance32(&payload); extent->flags = payload_advance32(&payload); - if (extent->length == 0 || - (client->info.min_block && !QEMU_IS_ALIGNED(extent->length, - client->info.min_block))) { + if (extent->length == 0) { error_setg(errp, "Protocol error: server sent status chunk with " - "invalid length"); + "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 |