--- /dev/null
+/* 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 int offset,
+ unsigned int length);
+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_iter = generic_file_read_iter,
+ .write_iter = 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 (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
+ _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 int offset,
+ unsigned int length)
+{
+ struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
+
+ _enter("{%lu},%u,%u", page->index, offset, length);
+
+ BUG_ON(!PageLocked(page));
+
+ /* we clean up only if the entire page is being invalidated */
+ if (offset == 0 && length == PAGE_CACHE_SIZE) {
+#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;
+}
Code Review / kvmfornfv.git / blobdiff