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-rw-r--r--fs/afs/file.c305
1 files changed, 305 insertions, 0 deletions
diff --git a/fs/afs/file.c b/fs/afs/file.c
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+/* file.c: AFS filesystem file handling
+ *
+ * Copyright (C) 2002 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/sched.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/buffer_head.h>
+#include "volume.h"
+#include "vnode.h"
+#include <rxrpc/call.h>
+#include "internal.h"
+
+#if 0
+static int afs_file_open(struct inode *inode, struct file *file);
+static int afs_file_release(struct inode *inode, struct file *file);
+#endif
+
+static int afs_file_readpage(struct file *file, struct page *page);
+static int afs_file_invalidatepage(struct page *page, unsigned long offset);
+static int afs_file_releasepage(struct page *page, int gfp_flags);
+
+static ssize_t afs_file_write(struct file *file, const char __user *buf,
+ size_t size, loff_t *off);
+
+struct inode_operations afs_file_inode_operations = {
+ .getattr = afs_inode_getattr,
+};
+
+struct file_operations afs_file_file_operations = {
+ .read = generic_file_read,
+ .write = afs_file_write,
+ .mmap = generic_file_mmap,
+#if 0
+ .open = afs_file_open,
+ .release = afs_file_release,
+ .fsync = afs_file_fsync,
+#endif
+};
+
+struct address_space_operations afs_fs_aops = {
+ .readpage = afs_file_readpage,
+ .sync_page = block_sync_page,
+ .set_page_dirty = __set_page_dirty_nobuffers,
+ .releasepage = afs_file_releasepage,
+ .invalidatepage = afs_file_invalidatepage,
+};
+
+/*****************************************************************************/
+/*
+ * AFS file write
+ */
+static ssize_t afs_file_write(struct file *file, const char __user *buf,
+ size_t size, loff_t *off)
+{
+ struct afs_vnode *vnode;
+
+ vnode = AFS_FS_I(file->f_dentry->d_inode);
+ if (vnode->flags & AFS_VNODE_DELETED)
+ return -ESTALE;
+
+ return -EIO;
+} /* end afs_file_write() */
+
+/*****************************************************************************/
+/*
+ * deal with notification that a page was read from the cache
+ */
+#ifdef AFS_CACHING_SUPPORT
+static void afs_file_readpage_read_complete(void *cookie_data,
+ struct page *page,
+ void *data,
+ int error)
+{
+ _enter("%p,%p,%p,%d", cookie_data, page, data, error);
+
+ if (error)
+ SetPageError(page);
+ else
+ SetPageUptodate(page);
+ unlock_page(page);
+
+} /* end afs_file_readpage_read_complete() */
+#endif
+
+/*****************************************************************************/
+/*
+ * deal with notification that a page was written to the cache
+ */
+#ifdef AFS_CACHING_SUPPORT
+static void afs_file_readpage_write_complete(void *cookie_data,
+ struct page *page,
+ void *data,
+ int error)
+{
+ _enter("%p,%p,%p,%d", cookie_data, page, data, error);
+
+ unlock_page(page);
+
+} /* end afs_file_readpage_write_complete() */
+#endif
+
+/*****************************************************************************/
+/*
+ * 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);
+
+ if (!PageLocked(page))
+ PAGE_BUG(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() */
+
+/*****************************************************************************/
+/*
+ * get a page cookie for the specified page
+ */
+#ifdef AFS_CACHING_SUPPORT
+int afs_cache_get_page_cookie(struct page *page,
+ struct cachefs_page **_page_cookie)
+{
+ int ret;
+
+ _enter("");
+ ret = cachefs_page_get_private(page,_page_cookie, GFP_NOIO);
+
+ _leave(" = %d", ret);
+ return ret;
+} /* end afs_cache_get_page_cookie() */
+#endif
+
+/*****************************************************************************/
+/*
+ * invalidate part or all of a page
+ */
+static int afs_file_invalidatepage(struct page *page, unsigned long offset)
+{
+ int ret = 1;
+
+ _enter("{%lu},%lu", page->index, offset);
+
+ BUG_ON(!PageLocked(page));
+
+ if (PagePrivate(page)) {
+#ifdef AFS_CACHING_SUPPORT
+ struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
+ cachefs_uncache_page(vnode->cache,page);
+#endif
+
+ /* We release buffers only if the entire page is being
+ * invalidated.
+ * The get_block cached value has been unconditionally
+ * invalidated, so real IO is not possible anymore.
+ */
+ if (offset == 0) {
+ BUG_ON(!PageLocked(page));
+
+ ret = 0;
+ if (!PageWriteback(page))
+ ret = page->mapping->a_ops->releasepage(page,
+ 0);
+ }
+ }
+
+ _leave(" = %d", ret);
+ return ret;
+} /* end afs_file_invalidatepage() */
+
+/*****************************************************************************/
+/*
+ * release a page and cleanup its private data
+ */
+static int afs_file_releasepage(struct page *page, int gfp_flags)
+{
+ struct cachefs_page *pageio;
+
+ _enter("{%lu},%x", page->index, gfp_flags);
+
+ if (PagePrivate(page)) {
+#ifdef AFS_CACHING_SUPPORT
+ struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
+ cachefs_uncache_page(vnode->cache, page);
+#endif
+
+ pageio = (struct cachefs_page *) page->private;
+ page->private = 0;
+ ClearPagePrivate(page);
+
+ if (pageio)
+ kfree(pageio);
+ }
+
+ _leave(" = 0");
+ return 0;
+} /* end afs_file_releasepage() */
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-11-23 06:50:11 +0000