1 files changed, 255 insertions, 0 deletions
diff --git a/fs/smb/client/fscache.c b/fs/smb/client/fscache.c
new file mode 100644
index 000000000..f64bad513
--- /dev/null
+++ b/fs/smb/client/fscache.c
@@ -0,0 +1,255 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ *   CIFS filesystem cache interface
+ *
+ *   Copyright (c) 2010 Novell, Inc.
+ *   Author(s): Suresh Jayaraman <sjayaraman@suse.de>
+ *
+ */
+#include "fscache.h"
+#include "cifsglob.h"
+#include "cifs_debug.h"
+#include "cifs_fs_sb.h"
+#include "cifsproto.h"
+
+static void cifs_fscache_fill_volume_coherency(
+	struct cifs_tcon *tcon,
+	struct cifs_fscache_volume_coherency_data *cd)
+{
+	memset(cd, 0, sizeof(*cd));
+	cd->resource_id		= cpu_to_le64(tcon->resource_id);
+	cd->vol_create_time	= tcon->vol_create_time;
+	cd->vol_serial_number	= cpu_to_le32(tcon->vol_serial_number);
+}
+
+int cifs_fscache_get_super_cookie(struct cifs_tcon *tcon)
+{
+	struct cifs_fscache_volume_coherency_data cd;
+	struct TCP_Server_Info *server = tcon->ses->server;
+	struct fscache_volume *vcookie;
+	const struct sockaddr *sa = (struct sockaddr *)&server->dstaddr;
+	size_t slen, i;
+	char *sharename;
+	char *key;
+	int ret = -ENOMEM;
+
+	tcon->fscache = NULL;
+	switch (sa->sa_family) {
+	case AF_INET:
+	case AF_INET6:
+		break;
+	default:
+		cifs_dbg(VFS, "Unknown network family '%d'\n", sa->sa_family);
+		return -EINVAL;
+	}
+
+	memset(&key, 0, sizeof(key));
+
+	sharename = extract_sharename(tcon->tree_name);
+	if (IS_ERR(sharename)) {
+		cifs_dbg(FYI, "%s: couldn't extract sharename\n", __func__);
+		return PTR_ERR(sharename);
+	}
+
+	slen = strlen(sharename);
+	for (i = 0; i < slen; i++)
+		if (sharename[i] == '/')
+			sharename[i] = ';';
+
+	key = kasprintf(GFP_KERNEL, "cifs,%pISpc,%s", sa, sharename);
+	if (!key)
+		goto out;
+
+	cifs_fscache_fill_volume_coherency(tcon, &cd);
+	vcookie = fscache_acquire_volume(key,
+					 NULL, /* preferred_cache */
+					 &cd, sizeof(cd));
+	cifs_dbg(FYI, "%s: (%s/0x%p)\n", __func__, key, vcookie);
+	if (IS_ERR(vcookie)) {
+		if (vcookie != ERR_PTR(-EBUSY)) {
+			ret = PTR_ERR(vcookie);
+			goto out_2;
+		}
+		pr_err("Cache volume key already in use (%s)\n", key);
+		vcookie = NULL;
+	}
+
+	tcon->fscache = vcookie;
+	ret = 0;
+out_2:
+	kfree(key);
+out:
+	kfree(sharename);
+	return ret;
+}
+
+void cifs_fscache_release_super_cookie(struct cifs_tcon *tcon)
+{
+	struct cifs_fscache_volume_coherency_data cd;
+
+	cifs_dbg(FYI, "%s: (0x%p)\n", __func__, tcon->fscache);
+
+	cifs_fscache_fill_volume_coherency(tcon, &cd);
+	fscache_relinquish_volume(tcon->fscache, &cd, false);
+	tcon->fscache = NULL;
+}
+
+void cifs_fscache_get_inode_cookie(struct inode *inode)
+{
+	struct cifs_fscache_inode_coherency_data cd;
+	struct cifsInodeInfo *cifsi = CIFS_I(inode);
+	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
+
+	cifs_fscache_fill_coherency(&cifsi->netfs.inode, &cd);
+
+	cifsi->netfs.cache =
+		fscache_acquire_cookie(tcon->fscache, 0,
+				       &cifsi->uniqueid, sizeof(cifsi->uniqueid),
+				       &cd, sizeof(cd),
+				       i_size_read(&cifsi->netfs.inode));
+	if (cifsi->netfs.cache)
+		mapping_set_release_always(inode->i_mapping);
+}
+
+void cifs_fscache_unuse_inode_cookie(struct inode *inode, bool update)
+{
+	if (update) {
+		struct cifs_fscache_inode_coherency_data cd;
+		loff_t i_size = i_size_read(inode);
+
+		cifs_fscache_fill_coherency(inode, &cd);
+		fscache_unuse_cookie(cifs_inode_cookie(inode), &cd, &i_size);
+	} else {
+		fscache_unuse_cookie(cifs_inode_cookie(inode), NULL, NULL);
+	}
+}
+
+void cifs_fscache_release_inode_cookie(struct inode *inode)
+{
+	struct cifsInodeInfo *cifsi = CIFS_I(inode);
+	struct fscache_cookie *cookie = cifs_inode_cookie(inode);
+
+	if (cookie) {
+		cifs_dbg(FYI, "%s: (0x%p)\n", __func__, cookie);
+		fscache_relinquish_cookie(cookie, false);
+		cifsi->netfs.cache = NULL;
+	}
+}
+
+/*
+ * Fallback page reading interface.
+ */
+static int fscache_fallback_read_page(struct inode *inode, struct page *page)
+{
+	struct netfs_cache_resources cres;
+	struct fscache_cookie *cookie = cifs_inode_cookie(inode);
+	struct iov_iter iter;
+	struct bio_vec bvec[1];
+	int ret;
+
+	memset(&cres, 0, sizeof(cres));
+	bvec[0].bv_page		= page;
+	bvec[0].bv_offset	= 0;
+	bvec[0].bv_len		= PAGE_SIZE;
+	iov_iter_bvec(&iter, ITER_DEST, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
+
+	ret = fscache_begin_read_operation(&cres, cookie);
+	if (ret < 0)
+		return ret;
+
+	ret = fscache_read(&cres, page_offset(page), &iter, NETFS_READ_HOLE_FAIL,
+			   NULL, NULL);
+	fscache_end_operation(&cres);
+	return ret;
+}
+
+/*
+ * Fallback page writing interface.
+ */
+static int fscache_fallback_write_page(struct inode *inode, struct page *page,
+				       bool no_space_allocated_yet)
+{
+	struct netfs_cache_resources cres;
+	struct fscache_cookie *cookie = cifs_inode_cookie(inode);
+	struct iov_iter iter;
+	struct bio_vec bvec[1];
+	loff_t start = page_offset(page);
+	size_t len = PAGE_SIZE;
+	int ret;
+
+	memset(&cres, 0, sizeof(cres));
+	bvec[0].bv_page		= page;
+	bvec[0].bv_offset	= 0;
+	bvec[0].bv_len		= PAGE_SIZE;
+	iov_iter_bvec(&iter, ITER_SOURCE, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
+
+	ret = fscache_begin_write_operation(&cres, cookie);
+	if (ret < 0)
+		return ret;
+
+	ret = cres.ops->prepare_write(&cres, &start, &len, i_size_read(inode),
+				      no_space_allocated_yet);
+	if (ret == 0)
+		ret = fscache_write(&cres, page_offset(page), &iter, NULL, NULL);
+	fscache_end_operation(&cres);
+	return ret;
+}
+
+/*
+ * Retrieve a page from FS-Cache
+ */
+int __cifs_readpage_from_fscache(struct inode *inode, struct page *page)
+{
+	int ret;
+
+	cifs_dbg(FYI, "%s: (fsc:%p, p:%p, i:0x%p\n",
+		 __func__, cifs_inode_cookie(inode), page, inode);
+
+	ret = fscache_fallback_read_page(inode, page);
+	if (ret < 0)
+		return ret;
+
+	/* Read completed synchronously */
+	SetPageUptodate(page);
+	return 0;
+}
+
+void __cifs_readpage_to_fscache(struct inode *inode, struct page *page)
+{
+	cifs_dbg(FYI, "%s: (fsc: %p, p: %p, i: %p)\n",
+		 __func__, cifs_inode_cookie(inode), page, inode);
+
+	fscache_fallback_write_page(inode, page, true);
+}
+
+/*
+ * Query the cache occupancy.
+ */
+int __cifs_fscache_query_occupancy(struct inode *inode,
+				   pgoff_t first, unsigned int nr_pages,
+				   pgoff_t *_data_first,
+				   unsigned int *_data_nr_pages)
+{
+	struct netfs_cache_resources cres;
+	struct fscache_cookie *cookie = cifs_inode_cookie(inode);
+	loff_t start, data_start;
+	size_t len, data_len;
+	int ret;
+
+	ret = fscache_begin_read_operation(&cres, cookie);
+	if (ret < 0)
+		return ret;
+
+	start = first * PAGE_SIZE;
+	len = nr_pages * PAGE_SIZE;
+	ret = cres.ops->query_occupancy(&cres, start, len, PAGE_SIZE,
+					&data_start, &data_len);
+	if (ret == 0) {
+		*_data_first = data_start / PAGE_SIZE;
+		*_data_nr_pages = len / PAGE_SIZE;
+	}
+
+	fscache_end_operation(&cres);
+	return ret;
+}