[PATCH] cifs: better instrumentation for coalesce_t2

[Jeff Layton]

When coalesce_t2 returns an error, have it throw a cFYI message that
explains the reason.

Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
 fs/cifs/connect.c |   29 +++++++++++++++++++++--------
 1 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 8cd4b52..cbf3b78 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -243,16 +243,21 @@ static int coalesce_t2(struct smb_hdr *psecond, struct smb_hdr *pTargetSMB)
 
 	remaining = total_data_size - total_in_buf;
 
-	if (remaining < 0)
+	if (remaining < 0) {
+		cFYI(1, "Server sent too much data. total_data_size=%hu "
+			"total_in_buf=%hu", total_data_size, total_in_buf);
 		return -EPROTO;
+	}
 
-	if (remaining == 0) /* nothing to do, ignore */
+	if (remaining == 0) {
+		/* nothing to do, ignore */
+		cFYI(1, "no more data remains");
 		return 0;
+	}
 
 	total_in_buf2 = get_unaligned_le16(&pSMB2->t2_rsp.DataCount);
-	if (remaining < total_in_buf2) {
+	if (remaining < total_in_buf2)
 		cFYI(1, "transact2 2nd response contains too much data");
-	}
 
 	/* find end of first SMB data area */
 	data_area_of_target = (char *)&pSMBt->hdr.Protocol +
@@ -267,23 +272,29 @@ static int coalesce_t2(struct smb_hdr *psecond, struct smb_hdr *pTargetSMB)
 	/* copy second buffer into end of first buffer */
 	total_in_buf += total_in_buf2;
 	/* is the result too big for the field? */
-	if (total_in_buf > USHRT_MAX)
+	if (total_in_buf > USHRT_MAX) {
+		cFYI(1, "coalesced total_in_buf too large (%u)", total_in_buf);
 		return -EPROTO;
+	}
 	put_unaligned_le16(total_in_buf, &pSMBt->t2_rsp.DataCount);
 
 	/* fix up the BCC */
 	byte_count = get_bcc(pTargetSMB);
 	byte_count += total_in_buf2;
 	/* 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;
 	/* don't allow buffer to overflow */
-	if (byte_count > CIFSMaxBufSize)
+	if (byte_count > CIFSMaxBufSize) {
+		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);
@@ -291,8 +302,10 @@ static int coalesce_t2(struct smb_hdr *psecond, struct smb_hdr *pTargetSMB)
 	if (remaining == total_in_buf2) {
 		cFYI(1, "found the last secondary response");
 		return 0; /* we are done */
-	} else /* more responses to go */
+	} else {/* more responses to go */
+		cFYI(1, "waiting for more secondary responses");
 		return 1;
+	}
 }
 
 static void
-- 
1.7.7.4


--MP_//.FiSwuzYm5ij6l1Hxxu2g4--
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