[PATCH v2 27/53] CIFS: Add read related address space operations for SMB2

[Pavel Shilovsky <piastry-7qunaywFIewox3rIn2DAYQ@public.gmane.org>]

From: Pavel Shilovsky <piastryyy-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

and temporarily disable readpages support.

Signed-off-by: Pavel Shilovsky <piastryyy-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 fs/cifs/cifsglob.h  |    3 +++
 fs/cifs/file.c      |   34 +++++++++++++++++++++++++++++-----
 fs/cifs/smb2file.c  |   13 ++++++++++++-
 fs/cifs/smb2pdu.c   |   20 +++++++++++++++-----
 fs/cifs/smb2proto.h |    4 ++++
 5 files changed, 63 insertions(+), 11 deletions(-)

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 1ab2767..465e87c 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -617,6 +617,9 @@ typedef int (iwrite_callback_t)(int, struct cifsFileInfo *,
 typedef int (iread_callback_t)(int, struct cifsFileInfo *,
 			       struct cifs_io_parms *, unsigned int *, char **,
 			       char **, int *);
+typedef int (read_callback_t)(int, struct cifsFileInfo *,
+			      struct cifs_io_parms *, unsigned int *, char **,
+			      int *, unsigned int);
 
 /*
  * Take a reference on the file private data. Must be called with
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 6eb1741..f20b38c 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2493,8 +2493,9 @@ ssize_t cifs_strict_readv(struct kiocb *iocb, const struct iovec *iov,
 	return cifs_user_readv(iocb, iov, nr_segs, pos);
 }
 
-static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
-			 loff_t *poffset)
+static ssize_t
+cifs_read_generic(struct file *file, char *read_data, size_t read_size,
+		  loff_t *poffset, read_callback_t *read_cb)
 {
 	int rc = -EACCES;
 	unsigned int bytes_read = 0;
@@ -2551,13 +2552,12 @@ static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
 				if (rc != 0)
 					break;
 			}
-			io_parms.netfid = open_file->netfid;
 			io_parms.pid = pid;
 			io_parms.tcon = pTcon;
 			io_parms.offset = *poffset;
 			io_parms.length = current_read_size;
-			rc = CIFSSMBRead(xid, &io_parms, &bytes_read,
-					 &current_offset, &buf_type);
+			rc = read_cb(xid, open_file, &io_parms, &bytes_read,
+				     &current_offset, &buf_type, 0);
 		}
 		if (rc || (bytes_read == 0)) {
 			if (total_read) {
@@ -2575,6 +2575,30 @@ static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
 	return total_read;
 }
 
+static int
+cifs_read_cb(int xid, struct cifsFileInfo *cfile, struct cifs_io_parms *parms,
+	     unsigned int *bytes_read, char **buf, int *buf_type,
+	     unsigned int remaining_bytes)
+{
+	parms->netfid = cfile->netfid;
+	return CIFSSMBRead(xid, parms, bytes_read, buf, buf_type);
+}
+
+static ssize_t
+cifs_read(struct file *file, char *read_data, size_t read_size, loff_t *offset)
+{
+#ifdef CONFIG_CIFS_SMB2
+	struct cifsFileInfo *cfile = (struct cifsFileInfo *)file->private_data;
+
+	if (tlink_tcon(cfile->tlink)->ses->server->is_smb2)
+		return cifs_read_generic(file, read_data, read_size, offset,
+					 smb2_read_cb);
+#endif
+
+	return cifs_read_generic(file, read_data, read_size, offset,
+				 cifs_read_cb);
+}
+
 /*
  * If the page is mmap'ed into a process' page tables, then we need to make
  * sure that it doesn't change while being written back.
diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c
index 1091934..b17e71c 100644
--- a/fs/cifs/smb2file.c
+++ b/fs/cifs/smb2file.c
@@ -150,7 +150,7 @@ const struct file_operations smb2_file_direct_nobrl_ops = {
 
 const struct address_space_operations smb2_addr_ops = {
 	.readpage = cifs_readpage,
-	.readpages = cifs_readpages,
+	/*.readpages = cifs_readpages,*/
 	.writepage = cifs_writepage,
 	.writepages = cifs_writepages,
 	.write_begin = cifs_write_begin,
@@ -436,3 +436,14 @@ ssize_t smb2_user_readv(struct kiocb *iocb, const struct iovec *iov,
 
 	return read;
 }
+
+int
+smb2_read_cb(int xid, struct cifsFileInfo *cfile, struct cifs_io_parms *parms,
+	     unsigned int *bytes_read, char **buf, int *buf_type,
+	     unsigned int remaining_bytes)
+{
+	parms->persist_fid = cfile->persist_fid;
+	parms->volatile_fid = cfile->volatile_fid;
+	return SMB2_read(xid, parms, bytes_read, buf, buf_type,
+			 remaining_bytes);
+}
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 2ff0acf..8d13b34 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -2311,7 +2311,7 @@ int new_read_req(struct kvec *iov, struct cifs_io_parms *io_parms,
 }
 
 int SMB2_read(const int xid, struct cifs_io_parms *io_parms,
-	      unsigned int *nbytes, char **buf, int *pbuf_type,
+	      unsigned int *nbytes, char **buf, int *buf_type,
 	      unsigned int remaining_bytes)
 {
 	int status, resp_buftype, rc = -EACCES;
@@ -2349,12 +2349,22 @@ int SMB2_read(const int xid, struct cifs_io_parms *io_parms,
 			*nbytes = 0;
 		}
 	}
-	if (resp_buftype != CIFS_NO_BUFFER) {
-		*buf = iov[0].iov_base;
+
+	if (*buf) {
+		memcpy(*buf, (char *)pSMB2r->hdr.ProtocolId +
+		       pSMB2r->DataOffset, *nbytes);
 		if (resp_buftype == CIFS_SMALL_BUFFER)
-			*pbuf_type = CIFS_SMALL_BUFFER;
+			cifs_small_buf_release(iov[0].iov_base);
 		else if (resp_buftype == CIFS_LARGE_BUFFER)
-			*pbuf_type = CIFS_LARGE_BUFFER;
+			cifs_buf_release(iov[0].iov_base);
+	} else {
+		if (resp_buftype != CIFS_NO_BUFFER) {
+			*buf = iov[0].iov_base;
+			if (resp_buftype == CIFS_SMALL_BUFFER)
+				*buf_type = CIFS_SMALL_BUFFER;
+			else if (resp_buftype == CIFS_LARGE_BUFFER)
+				*buf_type = CIFS_LARGE_BUFFER;
+		}
 	}
 	return rc;
 }
diff --git a/fs/cifs/smb2proto.h b/fs/cifs/smb2proto.h
index 810a7fc..d891915 100644
--- a/fs/cifs/smb2proto.h
+++ b/fs/cifs/smb2proto.h
@@ -119,6 +119,10 @@ extern struct cifsFileInfo *smb2_new_fileinfo(__u64 persist_fid,
 extern int smb2_reopen_file_cb(struct cifsFileInfo *cifs_file, int xid,
 			       struct cifs_tcon *tcon, const char *full_path,
 			       __u32 *oplock);
+extern int smb2_read_cb(int xid, struct cifsFileInfo *cfile,
+			struct cifs_io_parms *parms, unsigned int *bytes_read,
+			char **buf, int *buf_type,
+			unsigned int remaining_bytes);
 
 extern int smb2_open(struct inode *inode, struct file *file);
 extern ssize_t smb2_user_readv(struct kiocb *iocb, const struct iovec *iov,
-- 
1.7.1