cifs: Add a tracepoint to log EIO errors

Add a tracepoint to log EIO errors and give it the capacity to convey up to
two integers of information.  This is then wrapped with three functions:

 int smb_EIO(enum smb_eio_trace trace)
 int smb_EIO1(enum smb_eio_trace trace, unsigned long info)
 int smb_EIO2(enum smb_eio_trace trace, unsigned long info,
	      unsigned long info2)

depending on how many bits of info are desired to be logged with any
particular trace.  The functions all return -EIO and can be used in place
of -EIO.

The trace argument is an enum value that gets translated to a string when
the trace is printed.

This makes is easier to log EIO instances when the client is under high
load than turning on a printk wrapper such as cifs_dbg().  Granted, EIO
could have its own separate EIO printing since EIO shouldn't happen.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>

1 files changed, 8 insertions, 4 deletions

diff --git a/fs/smb/client/smb2inode.c b/fs/smb/client/smb2inode.c
index d0aad4821ed4..3e45e41f5713 100644
--- a/fs/smb/client/smb2inode.c
+++ b/fs/smb/client/smb2inode.c
@@ -31,16 +31,20 @@ static struct reparse_data_buffer *reparse_buf_ptr(struct kvec *iov)
 	struct reparse_data_buffer *buf;
 	struct smb2_ioctl_rsp *io = iov->iov_base;
 	u32 off, count, len;
+	u16 rdlen;
 
 	count = le32_to_cpu(io->OutputCount);
 	off = le32_to_cpu(io->OutputOffset);
 	if (check_add_overflow(off, count, &len) || len > iov->iov_len)
-		return ERR_PTR(-EIO);
+		return ERR_PTR(smb_EIO2(smb_eio_trace_reparse_overlong,
+					off, count));
 
 	buf = (struct reparse_data_buffer *)((u8 *)io + off);
 	len = sizeof(*buf);
-	if (count < len || count < le16_to_cpu(buf->ReparseDataLength) + len)
-		return ERR_PTR(-EIO);
+	rdlen = le16_to_cpu(buf->ReparseDataLength);
+
+	if (count < len || count < rdlen + len)
+		return ERR_PTR(smb_EIO2(smb_eio_trace_reparse_rdlen, count, rdlen));
 	return buf;
 }
 
@@ -1635,7 +1639,7 @@ int smb2_rename_pending_delete(const char *full_path,
 	} else {
 		cifs_tcon_dbg(FYI, "%s: failed to rename '%s' to '%s': %d\n",
 			      __func__, full_path, to_name, rc);
-		rc = -EIO;
+		rc = smb_EIO1(smb_eio_trace_pend_del_fail, rc);
 	}
 out:
 	cifs_put_tlink(tlink);