[PATCH] cifs: read/write operation fixes and cleanups

[Christoph Hellwig <hch@lst.de>]

 - support vectored and async aio ops unconditionally - this is above
   the pagecache and transparent to the fs
 - remove cifs_read_wrapper.  it was only doing silly checks and
   calling generic_file_write in all cases.
 - use do_sync_read/do_sync_write as read/write operations.  They call
   ->readv/->writev which we now always implemente.
 - add the filemap_fdatawrite calls to writev/aio_write which were
   missing previously compared to plain write.  no idea what the point
   behind them is, but let's be consistent at least..


Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/fs/cifs/cifsfs.c
===================================================================
--- linux-2.6.orig/fs/cifs/cifsfs.c	2005-10-31 14:59:17.000000000 +0100
+++ linux-2.6/fs/cifs/cifsfs.c	2005-10-31 15:30:35.000000000 +0100
@@ -443,57 +443,30 @@
 	return sb;
 }
 
-static ssize_t
-cifs_read_wrapper(struct file * file, char __user *read_data, size_t read_size,
-          loff_t * poffset)
-{
-	if(file->f_dentry == NULL)
-		return -EIO;
-	else if(file->f_dentry->d_inode == NULL)
-		return -EIO;
-
-	cFYI(1,("In read_wrapper size %zd at %lld",read_size,*poffset));
+static ssize_t cifs_file_writev(struct file *file, const struct iovec *iov,
+				unsigned long nr_segs, loff_t *ppos)
+{
+	struct inode *inode = file->f_dentry->d_inode;
+	ssize_t written;
 
-	if(CIFS_I(file->f_dentry->d_inode)->clientCanCacheRead) {
-		return generic_file_read(file,read_data,read_size,poffset);
-	} else {
-		/* BB do we need to lock inode from here until after invalidate? */
-/*		if(file->f_dentry->d_inode->i_mapping) {
-			filemap_fdatawrite(file->f_dentry->d_inode->i_mapping);
-			filemap_fdatawait(file->f_dentry->d_inode->i_mapping);
-		}*/
-/*		cifs_revalidate(file->f_dentry);*/ /* BB fixme */
-
-		/* BB we should make timer configurable - perhaps 
-		   by simply calling cifs_revalidate here */
-		/* invalidate_remote_inode(file->f_dentry->d_inode);*/
-		return generic_file_read(file,read_data,read_size,poffset);
-	}
+	written = generic_file_writev(file, iov, nr_segs, ppos);
+	if (!CIFS_I(inode)->clientCanCacheAll)
+		filemap_fdatawrite(inode->i_mapping);
+	return written;
 }
 
-static ssize_t
-cifs_write_wrapper(struct file * file, const char __user *write_data,
-           size_t write_size, loff_t * poffset) 
+static ssize_t cifs_file_aio_write(struct kiocb *iocb, const char __user *buf,
+				   size_t count, loff_t pos)
 {
+	struct inode *inode = iocb->ki_filp->f_dentry->d_inode;
 	ssize_t written;
 
-	if(file->f_dentry == NULL)
-		return -EIO;
-	else if(file->f_dentry->d_inode == NULL)
-		return -EIO;
-
-	cFYI(1,("In write_wrapper size %zd at %lld",write_size,*poffset));
-
-	written = generic_file_write(file,write_data,write_size,poffset);
-	if(!CIFS_I(file->f_dentry->d_inode)->clientCanCacheAll)  {
-		if(file->f_dentry->d_inode->i_mapping) {
-			filemap_fdatawrite(file->f_dentry->d_inode->i_mapping);
-		}
-	}
+	written = generic_file_aio_write(iocb, buf, count, pos);
+	if (!CIFS_I(inode)->clientCanCacheAll)
+		filemap_fdatawrite(inode->i_mapping);
 	return written;
 }
 
-
 static struct file_system_type cifs_fs_type = {
 	.owner = THIS_MODULE,
 	.name = "cifs",
@@ -554,8 +527,12 @@
 };
 
 struct file_operations cifs_file_ops = {
-	.read = cifs_read_wrapper,
-	.write = cifs_write_wrapper, 
+	.read = do_sync_read,
+	.write = do_sync_write,
+	.readv = generic_file_readv,
+	.writev = cifs_file_writev,
+	.aio_read = generic_file_aio_read,
+	.aio_write = cifs_file_aio_write,
 	.open = cifs_open,
 	.release = cifs_close,
 	.lock = cifs_lock,
@@ -568,10 +545,6 @@
 #endif /* CONFIG_CIFS_POSIX */
 
 #ifdef CONFIG_CIFS_EXPERIMENTAL
-	.readv = generic_file_readv,
-	.writev = generic_file_writev,
-	.aio_read = generic_file_aio_read,
-	.aio_write = generic_file_aio_write,
 	.dir_notify = cifs_dir_notify,
 #endif /* CONFIG_CIFS_EXPERIMENTAL */
 };