Ejemplo n.º 1
0
/*
 * AFS read page from file (or symlink)
 */
static int afs_file_readpage(struct file *file, struct page *page)
{
	struct afs_rxfs_fetch_descriptor desc;
#ifdef AFS_CACHING_SUPPORT
	struct cachefs_page *pageio;
#endif
	struct afs_vnode *vnode;
	struct inode *inode;
	int ret;

	inode = page->mapping->host;

	_enter("{%lu},{%lu}", inode->i_ino, page->index);

	vnode = AFS_FS_I(inode);

	BUG_ON(!PageLocked(page));

	ret = -ESTALE;
	if (vnode->flags & AFS_VNODE_DELETED)
		goto error;

#ifdef AFS_CACHING_SUPPORT
	ret = cachefs_page_get_private(page, &pageio, GFP_NOIO);
	if (ret < 0)
		goto error;

	/* is it cached? */
	ret = cachefs_read_or_alloc_page(vnode->cache,
					 page,
					 afs_file_readpage_read_complete,
					 NULL,
					 GFP_KERNEL);
#else
	ret = -ENOBUFS;
#endif

	switch (ret) {
		/* read BIO submitted and wb-journal entry found */
	case 1:
		BUG(); // TODO - handle wb-journal match

		/* read BIO submitted (page in cache) */
	case 0:
		break;

		/* no page available in cache */
	case -ENOBUFS:
	case -ENODATA:
	default:
		desc.fid	= vnode->fid;
		desc.offset	= page->index << PAGE_CACHE_SHIFT;
		desc.size	= min((size_t) (inode->i_size - desc.offset),
				      (size_t) PAGE_SIZE);
		desc.buffer	= kmap(page);

		clear_page(desc.buffer);

		/* read the contents of the file from the server into the
		 * page */
		ret = afs_vnode_fetch_data(vnode, &desc);
		kunmap(page);
		if (ret < 0) {
			if (ret==-ENOENT) {
				_debug("got NOENT from server"
				       " - marking file deleted and stale");
				vnode->flags |= AFS_VNODE_DELETED;
				ret = -ESTALE;
			}

#ifdef AFS_CACHING_SUPPORT
			cachefs_uncache_page(vnode->cache, page);
#endif
			goto error;
		}

		SetPageUptodate(page);

#ifdef AFS_CACHING_SUPPORT
		if (cachefs_write_page(vnode->cache,
				       page,
				       afs_file_readpage_write_complete,
				       NULL,
				       GFP_KERNEL) != 0
		    ) {
			cachefs_uncache_page(vnode->cache, page);
			unlock_page(page);
		}
#else
		unlock_page(page);
#endif
	}

	_leave(" = 0");
	return 0;

 error:
	SetPageError(page);
	unlock_page(page);

	_leave(" = %d", ret);
	return ret;

} /* end afs_file_readpage() */
Ejemplo n.º 2
0
/*
 * AFS read page from file, directory or symlink
 */
static int afs_readpage(struct file *file, struct page *page)
{
	struct afs_vnode *vnode;
	struct inode *inode;
	struct key *key;
	size_t len;
	off_t offset;
	int ret;

	inode = page->mapping->host;

	ASSERT(file != NULL);
	key = file->private_data;
	ASSERT(key != NULL);

	_enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index);

	vnode = AFS_FS_I(inode);

	BUG_ON(!PageLocked(page));

	ret = -ESTALE;
	if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
		goto error;

#ifdef AFS_CACHING_SUPPORT
	/* is it cached? */
	ret = cachefs_read_or_alloc_page(vnode->cache,
					 page,
					 afs_file_readpage_read_complete,
					 NULL,
					 GFP_KERNEL);
#else
	ret = -ENOBUFS;
#endif

	switch (ret) {
		/* read BIO submitted and wb-journal entry found */
	case 1:
		BUG(); // TODO - handle wb-journal match

		/* read BIO submitted (page in cache) */
	case 0:
		break;

		/* no page available in cache */
	case -ENOBUFS:
	case -ENODATA:
	default:
		offset = page->index << PAGE_CACHE_SHIFT;
		len = min_t(size_t, i_size_read(inode) - offset, PAGE_SIZE);

		/* read the contents of the file from the server into the
		 * page */
		ret = afs_vnode_fetch_data(vnode, key, offset, len, page);
		if (ret < 0) {
			if (ret == -ENOENT) {
				_debug("got NOENT from server"
				       " - marking file deleted and stale");
				set_bit(AFS_VNODE_DELETED, &vnode->flags);
				ret = -ESTALE;
			}
#ifdef AFS_CACHING_SUPPORT
			cachefs_uncache_page(vnode->cache, page);
#endif
			goto error;
		}

		SetPageUptodate(page);

#ifdef AFS_CACHING_SUPPORT
		if (cachefs_write_page(vnode->cache,
				       page,
				       afs_file_readpage_write_complete,
				       NULL,
				       GFP_KERNEL) != 0
		    ) {
			cachefs_uncache_page(vnode->cache, page);
			unlock_page(page);
		}
#else
		unlock_page(page);
#endif
	}

	_leave(" = 0");
	return 0;

error:
	SetPageError(page);
	unlock_page(page);
	_leave(" = %d", ret);
	return ret;
}