1 files changed, 378 insertions, 0 deletions
diff --git a/fs/afs/file.c b/fs/afs/file.c
new file mode 100644
index 00000000..14d89fa5
--- /dev/null
+++ b/fs/afs/file.c
@@ -0,0 +1,378 @@
+/* AFS filesystem file handling
+ *
+ * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/writeback.h>
+#include <linux/gfp.h>
+#include "internal.h"
+
+static int afs_readpage(struct file *file, struct page *page);
+static void afs_invalidatepage(struct page *page, unsigned long offset);
+static int afs_releasepage(struct page *page, gfp_t gfp_flags);
+static int afs_launder_page(struct page *page);
+
+static int afs_readpages(struct file *filp, struct address_space *mapping,
+			 struct list_head *pages, unsigned nr_pages);
+
+const struct file_operations afs_file_operations = {
+	.open		= afs_open,
+	.release	= afs_release,
+	.llseek		= generic_file_llseek,
+	.read		= do_sync_read,
+	.write		= do_sync_write,
+	.aio_read	= generic_file_aio_read,
+	.aio_write	= afs_file_write,
+	.mmap		= generic_file_readonly_mmap,
+	.splice_read	= generic_file_splice_read,
+	.fsync		= afs_fsync,
+	.lock		= afs_lock,
+	.flock		= afs_flock,
+};
+
+const struct inode_operations afs_file_inode_operations = {
+	.getattr	= afs_getattr,
+	.setattr	= afs_setattr,
+	.permission	= afs_permission,
+};
+
+const struct address_space_operations afs_fs_aops = {
+	.readpage	= afs_readpage,
+	.readpages	= afs_readpages,
+	.set_page_dirty	= afs_set_page_dirty,
+	.launder_page	= afs_launder_page,
+	.releasepage	= afs_releasepage,
+	.invalidatepage	= afs_invalidatepage,
+	.write_begin	= afs_write_begin,
+	.write_end	= afs_write_end,
+	.writepage	= afs_writepage,
+	.writepages	= afs_writepages,
+};
+
+/*
+ * open an AFS file or directory and attach a key to it
+ */
+int afs_open(struct inode *inode, struct file *file)
+{
+	struct afs_vnode *vnode = AFS_FS_I(inode);
+	struct key *key;
+	int ret;
+
+	_enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
+
+	key = afs_request_key(vnode->volume->cell);
+	if (IS_ERR(key)) {
+		_leave(" = %ld [key]", PTR_ERR(key));
+		return PTR_ERR(key);
+	}
+
+	ret = afs_validate(vnode, key);
+	if (ret < 0) {
+		_leave(" = %d [val]", ret);
+		return ret;
+	}
+
+	file->private_data = key;
+	_leave(" = 0");
+	return 0;
+}
+
+/*
+ * release an AFS file or directory and discard its key
+ */
+int afs_release(struct inode *inode, struct file *file)
+{
+	struct afs_vnode *vnode = AFS_FS_I(inode);
+
+	_enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
+
+	key_put(file->private_data);
+	_leave(" = 0");
+	return 0;
+}
+
+#ifdef CONFIG_AFS_FSCACHE
+/*
+ * deal with notification that a page was read from the cache
+ */
+static void afs_file_readpage_read_complete(struct page *page,
+					    void *data,
+					    int error)
+{
+	_enter("%p,%p,%d", page, data, error);
+
+	/* if the read completes with an error, we just unlock the page and let
+	 * the VM reissue the readpage */
+	if (!error)
+		SetPageUptodate(page);
+	unlock_page(page);
+}
+#endif
+
+/*
+ * read page from file, directory or symlink, given a key to use
+ */
+int afs_page_filler(void *data, struct page *page)
+{
+	struct inode *inode = page->mapping->host;
+	struct afs_vnode *vnode = AFS_FS_I(inode);
+	struct key *key = data;
+	size_t len;
+	off_t offset;
+	int ret;
+
+	_enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index);
+
+	BUG_ON(!PageLocked(page));
+
+	ret = -ESTALE;
+	if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
+		goto error;
+
+	/* is it cached? */
+#ifdef CONFIG_AFS_FSCACHE
+	ret = fscache_read_or_alloc_page(vnode->cache,
+					 page,
+					 afs_file_readpage_read_complete,
+					 NULL,
+					 GFP_KERNEL);
+#else
+	ret = -ENOBUFS;
+#endif
+	switch (ret) {
+		/* read BIO submitted (page in cache) */
+	case 0:
+		break;
+
+		/* page not yet cached */
+	case -ENODATA:
+		_debug("cache said ENODATA");
+		goto go_on;
+
+		/* page will not be cached */
+	case -ENOBUFS:
+		_debug("cache said ENOBUFS");
+	default:
+	go_on:
+		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 CONFIG_AFS_FSCACHE
+			fscache_uncache_page(vnode->cache, page);
+#endif
+			BUG_ON(PageFsCache(page));
+			goto error;
+		}
+
+		SetPageUptodate(page);
+
+		/* send the page to the cache */
+#ifdef CONFIG_AFS_FSCACHE
+		if (PageFsCache(page) &&
+		    fscache_write_page(vnode->cache, page, GFP_KERNEL) != 0) {
+			fscache_uncache_page(vnode->cache, page);
+			BUG_ON(PageFsCache(page));
+		}
+#endif
+		unlock_page(page);
+	}
+
+	_leave(" = 0");
+	return 0;
+
+error:
+	SetPageError(page);
+	unlock_page(page);
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * read page from file, directory or symlink, given a file to nominate the key
+ * to be used
+ */
+static int afs_readpage(struct file *file, struct page *page)
+{
+	struct key *key;
+	int ret;
+
+	if (file) {
+		key = file->private_data;
+		ASSERT(key != NULL);
+		ret = afs_page_filler(key, page);
+	} else {
+		struct inode *inode = page->mapping->host;
+		key = afs_request_key(AFS_FS_S(inode->i_sb)->volume->cell);
+		if (IS_ERR(key)) {
+			ret = PTR_ERR(key);
+		} else {
+			ret = afs_page_filler(key, page);
+			key_put(key);
+		}
+	}
+	return ret;
+}
+
+/*
+ * read a set of pages
+ */
+static int afs_readpages(struct file *file, struct address_space *mapping,
+			 struct list_head *pages, unsigned nr_pages)
+{
+	struct key *key = file->private_data;
+	struct afs_vnode *vnode;
+	int ret = 0;
+
+	_enter("{%d},{%lu},,%d",
+	       key_serial(key), mapping->host->i_ino, nr_pages);
+
+	ASSERT(key != NULL);
+
+	vnode = AFS_FS_I(mapping->host);
+	if (vnode->flags & AFS_VNODE_DELETED) {
+		_leave(" = -ESTALE");
+		return -ESTALE;
+	}
+
+	/* attempt to read as many of the pages as possible */
+#ifdef CONFIG_AFS_FSCACHE
+	ret = fscache_read_or_alloc_pages(vnode->cache,
+					  mapping,
+					  pages,
+					  &nr_pages,
+					  afs_file_readpage_read_complete,
+					  NULL,
+					  mapping_gfp_mask(mapping));
+#else
+	ret = -ENOBUFS;
+#endif
+
+	switch (ret) {
+		/* all pages are being read from the cache */
+	case 0:
+		BUG_ON(!list_empty(pages));
+		BUG_ON(nr_pages != 0);
+		_leave(" = 0 [reading all]");
+		return 0;
+
+		/* there were pages that couldn't be read from the cache */
+	case -ENODATA:
+	case -ENOBUFS:
+		break;
+
+		/* other error */
+	default:
+		_leave(" = %d", ret);
+		return ret;
+	}
+
+	/* load the missing pages from the network */
+	ret = read_cache_pages(mapping, pages, afs_page_filler, key);
+
+	_leave(" = %d [netting]", ret);
+	return ret;
+}
+
+/*
+ * write back a dirty page
+ */
+static int afs_launder_page(struct page *page)
+{
+	_enter("{%lu}", page->index);
+
+	return 0;
+}
+
+/*
+ * invalidate part or all of a page
+ * - release a page and clean up its private data if offset is 0 (indicating
+ *   the entire page)
+ */
+static void afs_invalidatepage(struct page *page, unsigned long offset)
+{
+	struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
+
+	_enter("{%lu},%lu", page->index, offset);
+
+	BUG_ON(!PageLocked(page));
+
+	/* we clean up only if the entire page is being invalidated */
+	if (offset == 0) {
+#ifdef CONFIG_AFS_FSCACHE
+		if (PageFsCache(page)) {
+			struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
+			fscache_wait_on_page_write(vnode->cache, page);
+			fscache_uncache_page(vnode->cache, page);
+		}
+#endif
+
+		if (PagePrivate(page)) {
+			if (wb && !PageWriteback(page)) {
+				set_page_private(page, 0);
+				afs_put_writeback(wb);
+			}
+
+			if (!page_private(page))
+				ClearPagePrivate(page);
+		}
+	}
+
+	_leave("");
+}
+
+/*
+ * release a page and clean up its private state if it's not busy
+ * - return true if the page can now be released, false if not
+ */
+static int afs_releasepage(struct page *page, gfp_t gfp_flags)
+{
+	struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
+	struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
+
+	_enter("{{%x:%u}[%lu],%lx},%x",
+	       vnode->fid.vid, vnode->fid.vnode, page->index, page->flags,
+	       gfp_flags);
+
+	/* deny if page is being written to the cache and the caller hasn't
+	 * elected to wait */
+#ifdef CONFIG_AFS_FSCACHE
+	if (!fscache_maybe_release_page(vnode->cache, page, gfp_flags)) {
+		_leave(" = F [cache busy]");
+		return 0;
+	}
+#endif
+
+	if (PagePrivate(page)) {
+		if (wb) {
+			set_page_private(page, 0);
+			afs_put_writeback(wb);
+		}
+		ClearPagePrivate(page);
+	}
+
+	/* indicate that the page can be released */
+	_leave(" = T");
+	return 1;
+}