diff options
Diffstat (limited to 'fs/cifs/transport.c')
| -rw-r--r-- | fs/cifs/transport.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c index 160463e22c95..914a7aaf9fa7 100644 --- a/fs/cifs/transport.c +++ b/fs/cifs/transport.c @@ -21,6 +21,7 @@ #include <asm/processor.h> #include <linux/mempool.h> #include <linux/sched/signal.h> +#include <linux/task_io_accounting_ops.h> #include "cifspdu.h" #include "cifsglob.h" #include "cifsproto.h" @@ -1638,3 +1639,181 @@ out: return -ERESTARTSYS; return rc; } + +/* + * Discard any remaining data in the current SMB. To do this, we borrow the + * current bigbuf. + */ +int +cifs_discard_remaining_data(struct TCP_Server_Info *server) +{ + unsigned int rfclen = server->pdu_size; + int remaining = rfclen + server->vals->header_preamble_size - + server->total_read; + + while (remaining > 0) { + int length; + + length = cifs_discard_from_socket(server, + min_t(size_t, remaining, + CIFSMaxBufSize + MAX_HEADER_SIZE(server))); + if (length < 0) + return length; + server->total_read += length; + remaining -= length; + } + + return 0; +} + +static int +__cifs_readv_discard(struct TCP_Server_Info *server, struct mid_q_entry *mid, + bool malformed) +{ + int length; + + length = cifs_discard_remaining_data(server); + dequeue_mid(mid, malformed); + mid->resp_buf = server->smallbuf; + server->smallbuf = NULL; + return length; +} + +static int +cifs_readv_discard(struct TCP_Server_Info *server, struct mid_q_entry *mid) +{ + struct cifs_readdata *rdata = mid->callback_data; + + return __cifs_readv_discard(server, mid, rdata->result); +} + +int +cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid) +{ + int length, len; + unsigned int data_offset, data_len; + struct cifs_readdata *rdata = mid->callback_data; + char *buf = server->smallbuf; + unsigned int buflen = server->pdu_size + + server->vals->header_preamble_size; + bool use_rdma_mr = false; + + cifs_dbg(FYI, "%s: mid=%llu offset=%llu bytes=%u\n", + __func__, mid->mid, rdata->offset, rdata->bytes); + + /* + * read the rest of READ_RSP header (sans Data array), or whatever we + * can if there's not enough data. At this point, we've read down to + * the Mid. + */ + len = min_t(unsigned int, buflen, server->vals->read_rsp_size) - + HEADER_SIZE(server) + 1; + + length = cifs_read_from_socket(server, + buf + HEADER_SIZE(server) - 1, len); + if (length < 0) + return length; + server->total_read += length; + + if (server->ops->is_session_expired && + server->ops->is_session_expired(buf)) { + cifs_reconnect(server, true); + return -1; + } + + if (server->ops->is_status_pending && + server->ops->is_status_pending(buf, server)) { + cifs_discard_remaining_data(server); + return -1; + } + + /* set up first two iov for signature check and to get credits */ + rdata->iov[0].iov_base = buf; + rdata->iov[0].iov_len = server->vals->header_preamble_size; + rdata->iov[1].iov_base = buf + server->vals->header_preamble_size; + rdata->iov[1].iov_len = + server->total_read - server->vals->header_preamble_size; + cifs_dbg(FYI, "0: iov_base=%p iov_len=%zu\n", + rdata->iov[0].iov_base, rdata->iov[0].iov_len); + cifs_dbg(FYI, "1: iov_base=%p iov_len=%zu\n", + rdata->iov[1].iov_base, rdata->iov[1].iov_len); + + /* Was the SMB read successful? */ + rdata->result = server->ops->map_error(buf, false); + if (rdata->result != 0) { + cifs_dbg(FYI, "%s: server returned error %d\n", + __func__, rdata->result); + /* normal error on read response */ + return __cifs_readv_discard(server, mid, false); + } + + /* Is there enough to get to the rest of the READ_RSP header? */ + if (server->total_read < server->vals->read_rsp_size) { + cifs_dbg(FYI, "%s: server returned short header. got=%u expected=%zu\n", + __func__, server->total_read, + server->vals->read_rsp_size); + rdata->result = -EIO; + return cifs_readv_discard(server, mid); + } + + data_offset = server->ops->read_data_offset(buf) + + server->vals->header_preamble_size; + if (data_offset < server->total_read) { + /* + * win2k8 sometimes sends an offset of 0 when the read + * is beyond the EOF. Treat it as if the data starts just after + * the header. + */ + cifs_dbg(FYI, "%s: data offset (%u) inside read response header\n", + __func__, data_offset); + data_offset = server->total_read; + } else if (data_offset > MAX_CIFS_SMALL_BUFFER_SIZE) { + /* data_offset is beyond the end of smallbuf */ + cifs_dbg(FYI, "%s: data offset (%u) beyond end of smallbuf\n", + __func__, data_offset); + rdata->result = -EIO; + return cifs_readv_discard(server, mid); + } + + cifs_dbg(FYI, "%s: total_read=%u data_offset=%u\n", + __func__, server->total_read, data_offset); + + len = data_offset - server->total_read; + if (len > 0) { + /* read any junk before data into the rest of smallbuf */ + length = cifs_read_from_socket(server, + buf + server->total_read, len); + if (length < 0) + return length; + server->total_read += length; + } + + /* how much data is in the response? */ +#ifdef CONFIG_CIFS_SMB_DIRECT + use_rdma_mr = rdata->mr; +#endif + data_len = server->ops->read_data_length(buf, use_rdma_mr); + if (!use_rdma_mr && (data_offset + data_len > buflen)) { + /* data_len is corrupt -- discard frame */ + rdata->result = -EIO; + return cifs_readv_discard(server, mid); + } + + length = rdata->read_into_pages(server, rdata, data_len); + if (length < 0) + return length; + + server->total_read += length; + + cifs_dbg(FYI, "total_read=%u buflen=%u remaining=%u\n", + server->total_read, buflen, data_len); + + /* discard anything left over */ + if (server->total_read < buflen) + return cifs_readv_discard(server, mid); + + dequeue_mid(mid, false); + mid->resp_buf = server->smallbuf; + server->smallbuf = NULL; + return length; +} |