[CIFS] Add support for legacy servers part 5

Handle small negotiated read sizes (under 4K) and finish up
read and write support.

Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/cifsproto.h

@@ -226,9 +226,6 @@ extern int SMBLegacyOpen(const int xid, struct cifsTconInfo *tcon,
 extern int CIFSSMBClose(const int xid, struct cifsTconInfo *tcon,
 			const int smb_file_id);
 
-extern int SMBLegacyRead(const int xid, struct cifsTconInfo *tcon,
-			const int netfid, unsigned int count,
-			const __u64 lseek, unsigned int *nbytes, char **buf);
 extern int CIFSSMBRead(const int xid, struct cifsTconInfo *tcon,
 			const int netfid, unsigned int count,
 			const __u64 lseek, unsigned int *nbytes, char **buf);

fs/cifs/cifssmb.c

@@ -923,81 +923,6 @@ openRetry:
 	return rc;
 }
 
-int
-SMBLegacyRead(const int xid, struct cifsTconInfo *tcon,
-            const int netfid, unsigned int count,
-            const __u64 lseek, unsigned int *nbytes, char **buf)
-{
-	int rc = -EACCES;
-	READX_REQ *pSMB = NULL;
-	READ_RSP *pSMBr = NULL;
-	char *pReadData = NULL;
-	int bytes_returned;
-
-	cFYI(1,("Legacy read %d bytes fid %d",count,netfid));
-
-	/* field is shorter in legacy read, only 16 bits */
-	if(count > 2048)
-		count = 2048;  /* BB FIXME make this configurable */
-
-	if(lseek > 0xFFFFFFFF)
-		return -EIO; /* can not read that far into file on old server */
-
-	*nbytes = 0;
-	rc = smb_init(SMB_COM_READ_ANDX, 10, tcon, (void **) &pSMB,
-		      (void **) &pSMBr);
-	if (rc)
-		return rc;
-
-	/* tcon and ses pointer are checked in smb_init */
-	if (tcon->ses->server == NULL)
-		return -ECONNABORTED;
-
-	pSMB->AndXCommand = 0xFF;       /* none */
-	pSMB->Fid = netfid;
-	pSMB->OffsetLow = cpu_to_le32(lseek & 0xFFFFFFFF);
-	pSMB->Remaining = 0;
-	pSMB->MaxCount = cpu_to_le16(count);
-	pSMB->Reserved = 0; /* Must Be Zero */
-	pSMB->ByteCount = 0;  /* no need to do le conversion since it is 0 */
-
-	rc = SendReceive(xid, tcon->ses, (struct smb_hdr *) pSMB,
-			 (struct smb_hdr *) pSMBr, &bytes_returned, 0);
-	cifs_stats_inc(&tcon->num_reads);
-	if (rc) {
-		cERROR(1, ("Send error in legacy read = %d", rc));
-	} else {
-		int data_length = le16_to_cpu(pSMBr->DataLengthHigh);
-		data_length = data_length << 16;
-		data_length += le16_to_cpu(pSMBr->DataLength);
-		*nbytes = data_length;
-
-		/*check that DataLength would not go beyond end of SMB */
-		if ((data_length > CIFSMaxBufSize) || (data_length > count)) {
-			cFYI(1,("bad length %d for count %d",data_length,count));
-			rc = -EIO;
-			*nbytes = 0;
-		} else {
-			pReadData = (char *) (&pSMBr->hdr.Protocol) +
-						le16_to_cpu(pSMBr->DataOffset);
-/*                      if(rc = copy_to_user(buf, pReadData, data_length)) {
-			 	cERROR(1,("Faulting on read rc = %d",rc));
-				rc = -EFAULT;
-			}*/ /* can not use copy_to_user when using page cache*/
-			if(*buf)
-				memcpy(*buf,pReadData,data_length);
-		}
-	}
-	if(*buf)
-		cifs_buf_release(pSMB);
-	else
-		*buf = (char *)pSMB;
-
-	/* Note: On -EAGAIN error only caller can retry on handle based calls
-		since file handle passed in no longer valid */
-	return rc;
-}
-
 /* If no buffer passed in, then caller wants to do the copy
 	as in the case of readpages so the SMB buffer must be
 	freed by the caller */
@@ -1012,11 +937,16 @@ CIFSSMBRead(const int xid, struct cifsTconInfo *tcon,
 	READ_RSP *pSMBr = NULL;
 	char *pReadData = NULL;
 	int bytes_returned;
+	int wct;
 
 	cFYI(1,("Reading %d bytes on fid %d",count,netfid));
+	if(tcon->ses->capabilities & CAP_LARGE_FILES)
+		wct = 12;
+	else
+		wct = 10; /* old style read */
 
 	*nbytes = 0;
-	rc = smb_init(SMB_COM_READ_ANDX, 12, tcon, (void **) &pSMB,
+	rc = smb_init(SMB_COM_READ_ANDX, wct, tcon, (void **) &pSMB,
 		      (void **) &pSMBr);
 	if (rc)
 		return rc;
@@ -1028,11 +958,22 @@ CIFSSMBRead(const int xid, struct cifsTconInfo *tcon,
 	pSMB->AndXCommand = 0xFF;	/* none */
 	pSMB->Fid = netfid;
 	pSMB->OffsetLow = cpu_to_le32(lseek & 0xFFFFFFFF);
+	if(wct == 12)
 		pSMB->OffsetHigh = cpu_to_le32(lseek >> 32);
+        else if((lseek >> 32) > 0) /* can not handle this big offset for old */
+                return -EIO;
+
 	pSMB->Remaining = 0;
 	pSMB->MaxCount = cpu_to_le16(count & 0xFFFF);
 	pSMB->MaxCountHigh = cpu_to_le32(count >> 16);
-	pSMB->ByteCount = 0;  /* no need to do le conversion since it is 0 */
+	if(wct == 12)
+		pSMB->ByteCount = 0;  /* no need to do le conversion since 0 */
+	else {
+		/* old style read */
+		struct smb_com_readx_req * pSMBW = 
+			(struct smb_com_readx_req *)pSMB;
+		pSMBW->ByteCount = 0;	
+	}
 	
 	rc = SendReceive(xid, tcon->ses, (struct smb_hdr *) pSMB,
 			 (struct smb_hdr *) pSMBr, &bytes_returned, 0);

fs/cifs/file.c

@@ -1183,16 +1183,11 @@ ssize_t cifs_user_read(struct file *file, char __user *read_data,
 	char *smb_read_data;
 	char __user *current_offset;
 	struct smb_com_read_rsp *pSMBr;
-	int use_old_read = FALSE;
 
 	xid = GetXid();
 	cifs_sb = CIFS_SB(file->f_dentry->d_sb);
 	pTcon = cifs_sb->tcon;
 
-	if(pTcon->ses)
-		if((pTcon->ses->capabilities & CAP_LARGE_FILES) == 0)
-			use_old_read = TRUE;
-
 	if (file->private_data == NULL) {
 		FreeXid(xid);
 		return -EBADF;
@@ -1217,22 +1212,10 @@ ssize_t cifs_user_read(struct file *file, char __user *read_data,
 				if (rc != 0)
 					break;
 			}
-			if(use_old_read)
-				rc = SMBLegacyRead(xid, pTcon,
-					open_file->netfid,
-					current_read_size, *poffset,
-					&bytes_read, &smb_read_data);
-			else {
 			rc = CIFSSMBRead(xid, pTcon,
 					open_file->netfid,
 					current_read_size, *poffset,
 					&bytes_read, &smb_read_data);
-				if(rc == -EINVAL) {
-					use_old_read = TRUE;
-					rc = -EAGAIN;
-					continue;
-				}
-			}
 			pSMBr = (struct smb_com_read_rsp *)smb_read_data;
 			if (copy_to_user(current_offset, 
 					 smb_read_data + 4 /* RFC1001 hdr */
@@ -1276,7 +1259,6 @@ static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
 	int xid;
 	char *current_offset;
 	struct cifsFileInfo *open_file;
-	int use_old_read = FALSE;
 
 	xid = GetXid();
 	cifs_sb = CIFS_SB(file->f_dentry->d_sb);
@@ -1287,9 +1269,6 @@ static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
 		return -EBADF;
 	}
 	open_file = (struct cifsFileInfo *)file->private_data;
-	if(pTcon->ses)
-		if((pTcon->ses->capabilities & CAP_LARGE_FILES) == 0)
-			use_old_read = TRUE;
 
 	if ((file->f_flags & O_ACCMODE) == O_WRONLY)
 		cFYI(1, ("attempting read on write only file instance"));
@@ -1308,24 +1287,10 @@ static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
 				if (rc != 0)
 					break;
 			}
-			if(use_old_read) 
-				rc = SMBLegacyRead(xid, pTcon,
-					 open_file->netfid,
-					 current_read_size, *poffset,
-					 &bytes_read, &current_offset);
-			else {
 			rc = CIFSSMBRead(xid, pTcon,
 					open_file->netfid,
 					current_read_size, *poffset,
 					&bytes_read, &current_offset);
-				/* check if server disavows support for
-				   64 bit offsets */
-				if(rc == -EINVAL) {
-					rc = -EAGAIN;
-					use_old_read = TRUE;
-					continue;
-				}
-			}
 		}
 		if (rc || (bytes_read == 0)) {
 			if (total_read) {
@@ -1423,7 +1388,6 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
 	struct smb_com_read_rsp *pSMBr;
 	struct pagevec lru_pvec;
 	struct cifsFileInfo *open_file;
-	int use_old_read = FALSE;
 
 	xid = GetXid();
 	if (file->private_data == NULL) {
@@ -1433,9 +1397,7 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
 	open_file = (struct cifsFileInfo *)file->private_data;
 	cifs_sb = CIFS_SB(file->f_dentry->d_sb);
 	pTcon = cifs_sb->tcon;
-	if(pTcon->ses)
+
-		if((pTcon->ses->capabilities & CAP_LARGE_FILES) == 0)
-			use_old_read = TRUE;
 	pagevec_init(&lru_pvec, 0);
 
 	for (i = 0; i < num_pages; ) {
@@ -1481,22 +1443,10 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
 					break;
 			}
 
-			if(use_old_read)
-				rc = SMBLegacyRead(xid, pTcon,
-					open_file->netfid,
-					read_size, offset,
-					&bytes_read, &smb_read_data);
-			else {
 			rc = CIFSSMBRead(xid, pTcon,
 					open_file->netfid,
 					read_size, offset,
 					&bytes_read, &smb_read_data);
-				if(rc == -EINVAL) {
-					use_old_read = TRUE;
-					rc = -EAGAIN;
-					continue;
-				}
-			}
 
 			/* BB more RC checks ? */
 			if (rc== -EAGAIN) {

fs/cifs/inode.c

@@ -169,6 +169,10 @@ int cifs_get_inode_info_unix(struct inode **pinode,
 			if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
 				inode->i_fop->lock = NULL;
 			inode->i_data.a_ops = &cifs_addr_ops;
+			/* check if server can support readpages */
+			if(pTcon->ses->server->maxBuf < 
+			    4096 + MAX_CIFS_HDR_SIZE)
+				inode->i_data.a_ops->readpages = NULL;
 		} else if (S_ISDIR(inode->i_mode)) {
 			cFYI(1, (" Directory inode"));
 			inode->i_op = &cifs_dir_inode_ops;
@@ -384,6 +388,9 @@ int cifs_get_inode_info(struct inode **pinode,
 			if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
 				inode->i_fop->lock = NULL;
 			inode->i_data.a_ops = &cifs_addr_ops;
+			if(pTcon->ses->server->maxBuf < 
+			     4096 + MAX_CIFS_HDR_SIZE)
+				inode->i_data.a_ops->readpages = NULL;
 		} else if (S_ISDIR(inode->i_mode)) {
 			cFYI(1, (" Directory inode "));
 			inode->i_op = &cifs_dir_inode_ops;

fs/cifs/readdir.c

@@ -200,7 +200,10 @@ static void fill_in_inode(struct inode *tmp_inode,
 		if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
 			tmp_inode->i_fop->lock = NULL;
 		tmp_inode->i_data.a_ops = &cifs_addr_ops;
-
+		if((cifs_sb->tcon) && (cifs_sb->tcon->ses) &&
+		   (cifs_sb->tcon->ses->server->maxBuf <
+			4096 + MAX_CIFS_HDR_SIZE))
+			tmp_inode->i_data.a_ops->readpages = NULL;
 		if(isNewInode)
 			return; /* No sense invalidating pages for new inode
 				   since have not started caching readahead file
@@ -306,6 +309,10 @@ static void unix_fill_in_inode(struct inode *tmp_inode,
 		if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
 			tmp_inode->i_fop->lock = NULL;
 		tmp_inode->i_data.a_ops = &cifs_addr_ops;
+		if((cifs_sb->tcon) && (cifs_sb->tcon->ses) &&
+		   (cifs_sb->tcon->ses->server->maxBuf < 
+			4096 + MAX_CIFS_HDR_SIZE))
+			tmp_inode->i_data.a_ops->readpages = NULL;
 
 		if(isNewInode)
 			return; /* No sense invalidating pages for new inode since we