cifs: better instrumentation for coalesce_t2
When coalesce_t2 returns an error, have it throw a cFYI message that
explains the reason. Also rename some variables to clarify what they
represent.
Reported-and-Tested-by: Konstantinos Skarlatos <k.skarlatos@gmail.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 4666780..5cc1585 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -225,74 +225,90 @@
static int coalesce_t2(struct smb_hdr *psecond, struct smb_hdr *pTargetSMB)
{
- struct smb_t2_rsp *pSMB2 = (struct smb_t2_rsp *)psecond;
+ struct smb_t2_rsp *pSMBs = (struct smb_t2_rsp *)psecond;
struct smb_t2_rsp *pSMBt = (struct smb_t2_rsp *)pTargetSMB;
- char *data_area_of_target;
- char *data_area_of_buf2;
+ char *data_area_of_tgt;
+ char *data_area_of_src;
int remaining;
- unsigned int byte_count, total_in_buf;
- __u16 total_data_size, total_in_buf2;
+ unsigned int byte_count, total_in_tgt;
+ __u16 tgt_total_cnt, src_total_cnt, total_in_src;
- total_data_size = get_unaligned_le16(&pSMBt->t2_rsp.TotalDataCount);
+ src_total_cnt = get_unaligned_le16(&pSMBs->t2_rsp.TotalDataCount);
+ tgt_total_cnt = get_unaligned_le16(&pSMBt->t2_rsp.TotalDataCount);
- if (total_data_size !=
- get_unaligned_le16(&pSMB2->t2_rsp.TotalDataCount))
- cFYI(1, "total data size of primary and secondary t2 differ");
+ if (tgt_total_cnt != src_total_cnt)
+ cFYI(1, "total data count of primary and secondary t2 differ "
+ "source=%hu target=%hu", src_total_cnt, tgt_total_cnt);
- total_in_buf = get_unaligned_le16(&pSMBt->t2_rsp.DataCount);
+ total_in_tgt = get_unaligned_le16(&pSMBt->t2_rsp.DataCount);
- remaining = total_data_size - total_in_buf;
+ remaining = tgt_total_cnt - total_in_tgt;
- if (remaining < 0)
+ if (remaining < 0) {
+ cFYI(1, "Server sent too much data. tgt_total_cnt=%hu "
+ "total_in_tgt=%hu", tgt_total_cnt, total_in_tgt);
return -EPROTO;
-
- if (remaining == 0) /* nothing to do, ignore */
- return 0;
-
- total_in_buf2 = get_unaligned_le16(&pSMB2->t2_rsp.DataCount);
- if (remaining < total_in_buf2) {
- cFYI(1, "transact2 2nd response contains too much data");
}
+ if (remaining == 0) {
+ /* nothing to do, ignore */
+ cFYI(1, "no more data remains");
+ return 0;
+ }
+
+ total_in_src = get_unaligned_le16(&pSMBs->t2_rsp.DataCount);
+ if (remaining < total_in_src)
+ cFYI(1, "transact2 2nd response contains too much data");
+
/* find end of first SMB data area */
- data_area_of_target = (char *)&pSMBt->hdr.Protocol +
+ data_area_of_tgt = (char *)&pSMBt->hdr.Protocol +
get_unaligned_le16(&pSMBt->t2_rsp.DataOffset);
+
/* validate target area */
+ data_area_of_src = (char *)&pSMBs->hdr.Protocol +
+ get_unaligned_le16(&pSMBs->t2_rsp.DataOffset);
- data_area_of_buf2 = (char *)&pSMB2->hdr.Protocol +
- get_unaligned_le16(&pSMB2->t2_rsp.DataOffset);
+ data_area_of_tgt += total_in_tgt;
- data_area_of_target += total_in_buf;
-
- /* copy second buffer into end of first buffer */
- total_in_buf += total_in_buf2;
+ total_in_tgt += total_in_src;
/* is the result too big for the field? */
- if (total_in_buf > USHRT_MAX)
+ if (total_in_tgt > USHRT_MAX) {
+ cFYI(1, "coalesced DataCount too large (%u)", total_in_tgt);
return -EPROTO;
- put_unaligned_le16(total_in_buf, &pSMBt->t2_rsp.DataCount);
+ }
+ put_unaligned_le16(total_in_tgt, &pSMBt->t2_rsp.DataCount);
/* fix up the BCC */
byte_count = get_bcc(pTargetSMB);
- byte_count += total_in_buf2;
+ byte_count += total_in_src;
/* is the result too big for the field? */
- if (byte_count > USHRT_MAX)
+ if (byte_count > USHRT_MAX) {
+ cFYI(1, "coalesced BCC too large (%u)", byte_count);
return -EPROTO;
+ }
put_bcc(byte_count, pTargetSMB);
byte_count = be32_to_cpu(pTargetSMB->smb_buf_length);
- byte_count += total_in_buf2;
+ byte_count += total_in_src;
/* don't allow buffer to overflow */
- if (byte_count > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4)
+ if (byte_count > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
+ cFYI(1, "coalesced BCC exceeds buffer size (%u)", byte_count);
return -ENOBUFS;
+ }
pTargetSMB->smb_buf_length = cpu_to_be32(byte_count);
- memcpy(data_area_of_target, data_area_of_buf2, total_in_buf2);
+ /* copy second buffer into end of first buffer */
+ memcpy(data_area_of_tgt, data_area_of_src, total_in_src);
- if (remaining == total_in_buf2) {
- cFYI(1, "found the last secondary response");
- return 0; /* we are done */
- } else /* more responses to go */
+ if (remaining != total_in_src) {
+ /* more responses to go */
+ cFYI(1, "waiting for more secondary responses");
return 1;
+ }
+
+ /* we are done */
+ cFYI(1, "found the last secondary response");
+ return 0;
}
static void