Commit e959b549 authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Eric Van Hensbergen
Browse files

fs/9p: Add direct IO support in cached mode 



Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatarVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: default avatarEric Van Hensbergen <ericvh@gmail.com>
parent fa6ea161

fs/9p/vfs_addr.c

+3 −2
Original line number Diff line number Diff line
@@ -254,7 +254,8 @@ static int v9fs_launder_page(struct page *page) 
 * with an error.

 *

 */

ssize_t v9fs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,

static ssize_t

v9fs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,

	       loff_t pos, unsigned long nr_segs)

{

	/*

fs/9p/vfs_file.c

+113 −4
Original line number Diff line number Diff line
@@ -579,15 +579,124 @@ v9fs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) 
	return VM_FAULT_NOPAGE;

}



static ssize_t

v9fs_direct_read(struct file *filp, char __user *udata, size_t count,

		 loff_t *offsetp)

{

	loff_t size, offset;

	struct inode *inode;

	struct address_space *mapping;



	offset = *offsetp;

	mapping = filp->f_mapping;

	inode = mapping->host;

	if (!count)

		return 0;

	size = i_size_read(inode);

	if (offset < size)

		filemap_write_and_wait_range(mapping, offset,

					     offset + count - 1);



	return v9fs_file_read(filp, udata, count, offsetp);

}



/**

 * v9fs_cached_file_read - read from a file

 * @filp: file pointer to read

 * @udata: user data buffer to read data into

 * @count: size of buffer

 * @offset: offset at which to read data

 *

 */

static ssize_t

v9fs_cached_file_read(struct file *filp, char __user *data, size_t count,

		      loff_t *offset)

{

	if (filp->f_flags & O_DIRECT)

		return v9fs_direct_read(filp, data, count, offset);

	return do_sync_read(filp, data, count, offset);

}



static ssize_t

v9fs_direct_write(struct file *filp, const char __user * data,

		  size_t count, loff_t *offsetp)

{

	loff_t offset;

	ssize_t retval;

	struct inode *inode;

	struct address_space *mapping;



	offset = *offsetp;

	mapping = filp->f_mapping;

	inode = mapping->host;

	if (!count)

		return 0;



	mutex_lock(&inode->i_mutex);

	retval = filemap_write_and_wait_range(mapping, offset,

					      offset + count - 1);

	if (retval)

		goto err_out;

	/*

	 * After a write we want buffered reads to be sure to go to disk to get

	 * the new data.  We invalidate clean cached page from the region we're

	 * about to write.  We do this *before* the write so that if we fail

	 * here we fall back to buffered write

	 */

	if (mapping->nrpages) {

		pgoff_t pg_start = offset >> PAGE_CACHE_SHIFT;

		pgoff_t pg_end   = (offset + count - 1) >> PAGE_CACHE_SHIFT;



		retval = invalidate_inode_pages2_range(mapping,

							pg_start, pg_end);

		/*

		 * If a page can not be invalidated, fall back

		 * to buffered write.

		 */

		if (retval) {

			if (retval == -EBUSY)

				goto buff_write;

			goto err_out;

		}

	}

	retval = v9fs_file_write(filp, data, count, offsetp);

err_out:

	mutex_unlock(&inode->i_mutex);

	return retval;



buff_write:

	mutex_unlock(&inode->i_mutex);

	return do_sync_write(filp, data, count, offsetp);

}



/**

 * v9fs_cached_file_write - write to a file

 * @filp: file pointer to write

 * @data: data buffer to write data from

 * @count: size of buffer

 * @offset: offset at which to write data

 *

 */

static ssize_t

v9fs_cached_file_write(struct file *filp, const char __user * data,

		       size_t count, loff_t *offset)

{



	if (filp->f_flags & O_DIRECT)

		return v9fs_direct_write(filp, data, count, offset);

	return do_sync_write(filp, data, count, offset);

}



static const struct vm_operations_struct v9fs_file_vm_ops = {

	.fault = filemap_fault,

	.page_mkwrite = v9fs_vm_page_mkwrite,

};





const struct file_operations v9fs_cached_file_operations = {

	.llseek = generic_file_llseek,

	.read = do_sync_read,

	.write = do_sync_write,

	.read = v9fs_cached_file_read,

	.write = v9fs_cached_file_write,

	.aio_read = generic_file_aio_read,

	.aio_write = generic_file_aio_write,

	.open = v9fs_file_open,
@@ -599,8 +708,8 @@ const struct file_operations v9fs_cached_file_operations = { 


const struct file_operations v9fs_cached_file_operations_dotl = {

	.llseek = generic_file_llseek,

	.read = do_sync_read,

	.write = do_sync_write,

	.read = v9fs_cached_file_read,

	.write = v9fs_cached_file_write,

	.aio_read = generic_file_aio_read,

	.aio_write = generic_file_aio_write,

	.open = v9fs_file_open,