1// SPDX-License-Identifier: LGPL-2.1
  2/*
  3 *   CIFS filesystem cache interface
  4 *
  5 *   Copyright (c) 2010 Novell, Inc.
  6 *   Author(s): Suresh Jayaraman <sjayaraman@suse.de>
  7 *
  8 */
  9#include "fscache.h"
 10#include "cifsglob.h"
 11#include "cifs_debug.h"
 12#include "cifs_fs_sb.h"
 13#include "cifsproto.h"
 14
 15static void cifs_fscache_fill_volume_coherency(
 16	struct cifs_tcon *tcon,
 17	struct cifs_fscache_volume_coherency_data *cd)
 18{
 19	memset(cd, 0, sizeof(*cd));
 20	cd->resource_id		= cpu_to_le64(tcon->resource_id);
 21	cd->vol_create_time	= tcon->vol_create_time;
 22	cd->vol_serial_number	= cpu_to_le32(tcon->vol_serial_number);
 23}
 24
 25int cifs_fscache_get_super_cookie(struct cifs_tcon *tcon)
 26{
 27	struct cifs_fscache_volume_coherency_data cd;
 28	struct TCP_Server_Info *server = tcon->ses->server;
 29	struct fscache_volume *vcookie;
 30	const struct sockaddr *sa = (struct sockaddr *)&server->dstaddr;
 31	size_t slen, i;
 32	char *sharename;
 33	char *key;
 34	int ret = -ENOMEM;
 35
 36	tcon->fscache = NULL;
 37	switch (sa->sa_family) {
 38	case AF_INET:
 39	case AF_INET6:
 40		break;
 41	default:
 42		cifs_dbg(VFS, "Unknown network family '%d'\n", sa->sa_family);
 43		return -EINVAL;
 44	}
 45
 46	memset(&key, 0, sizeof(key));
 47
 48	sharename = extract_sharename(tcon->tree_name);
 49	if (IS_ERR(sharename)) {
 50		cifs_dbg(FYI, "%s: couldn't extract sharename\n", __func__);
 51		return -EINVAL;
 52	}
 53
 54	slen = strlen(sharename);
 55	for (i = 0; i < slen; i++)
 56		if (sharename[i] == '/')
 57			sharename[i] = ';';
 58
 59	key = kasprintf(GFP_KERNEL, "cifs,%pISpc,%s", sa, sharename);
 60	if (!key)
 61		goto out;
 62
 63	cifs_fscache_fill_volume_coherency(tcon, &cd);
 64	vcookie = fscache_acquire_volume(key,
 65					 NULL, /* preferred_cache */
 66					 &cd, sizeof(cd));
 67	cifs_dbg(FYI, "%s: (%s/0x%p)\n", __func__, key, vcookie);
 68	if (IS_ERR(vcookie)) {
 69		if (vcookie != ERR_PTR(-EBUSY)) {
 70			ret = PTR_ERR(vcookie);
 71			goto out_2;
 72		}
 73		pr_err("Cache volume key already in use (%s)\n", key);
 74		vcookie = NULL;
 75	}
 76
 77	tcon->fscache = vcookie;
 78	ret = 0;
 79out_2:
 80	kfree(key);
 81out:
 82	kfree(sharename);
 83	return ret;
 84}
 85
 86void cifs_fscache_release_super_cookie(struct cifs_tcon *tcon)
 87{
 88	struct cifs_fscache_volume_coherency_data cd;
 89
 90	cifs_dbg(FYI, "%s: (0x%p)\n", __func__, tcon->fscache);
 91
 92	cifs_fscache_fill_volume_coherency(tcon, &cd);
 93	fscache_relinquish_volume(tcon->fscache, &cd, false);
 94	tcon->fscache = NULL;
 95}
 96
 97void cifs_fscache_get_inode_cookie(struct inode *inode)
 98{
 99	struct cifs_fscache_inode_coherency_data cd;
100	struct cifsInodeInfo *cifsi = CIFS_I(inode);
101	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
102	struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
103
104	cifs_fscache_fill_coherency(&cifsi->netfs.inode, &cd);
105
106	cifsi->netfs.cache =
107		fscache_acquire_cookie(tcon->fscache, 0,
108				       &cifsi->uniqueid, sizeof(cifsi->uniqueid),
109				       &cd, sizeof(cd),
110				       i_size_read(&cifsi->netfs.inode));
111}
112
113void cifs_fscache_unuse_inode_cookie(struct inode *inode, bool update)
114{
115	if (update) {
116		struct cifs_fscache_inode_coherency_data cd;
117		loff_t i_size = i_size_read(inode);
118
119		cifs_fscache_fill_coherency(inode, &cd);
120		fscache_unuse_cookie(cifs_inode_cookie(inode), &cd, &i_size);
121	} else {
122		fscache_unuse_cookie(cifs_inode_cookie(inode), NULL, NULL);
123	}
124}
125
126void cifs_fscache_release_inode_cookie(struct inode *inode)
127{
128	struct cifsInodeInfo *cifsi = CIFS_I(inode);
129	struct fscache_cookie *cookie = cifs_inode_cookie(inode);
130
131	if (cookie) {
132		cifs_dbg(FYI, "%s: (0x%p)\n", __func__, cookie);
133		fscache_relinquish_cookie(cookie, false);
134		cifsi->netfs.cache = NULL;
135	}
136}
137
138/*
139 * Fallback page reading interface.
140 */
141static int fscache_fallback_read_page(struct inode *inode, struct page *page)
142{
143	struct netfs_cache_resources cres;
144	struct fscache_cookie *cookie = cifs_inode_cookie(inode);
145	struct iov_iter iter;
146	struct bio_vec bvec[1];
147	int ret;
148
149	memset(&cres, 0, sizeof(cres));
150	bvec[0].bv_page		= page;
151	bvec[0].bv_offset	= 0;
152	bvec[0].bv_len		= PAGE_SIZE;
153	iov_iter_bvec(&iter, ITER_DEST, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
154
155	ret = fscache_begin_read_operation(&cres, cookie);
156	if (ret < 0)
157		return ret;
158
159	ret = fscache_read(&cres, page_offset(page), &iter, NETFS_READ_HOLE_FAIL,
160			   NULL, NULL);
161	fscache_end_operation(&cres);
162	return ret;
163}
164
165/*
166 * Fallback page writing interface.
167 */
168static int fscache_fallback_write_page(struct inode *inode, struct page *page,
169				       bool no_space_allocated_yet)
170{
171	struct netfs_cache_resources cres;
172	struct fscache_cookie *cookie = cifs_inode_cookie(inode);
173	struct iov_iter iter;
174	struct bio_vec bvec[1];
175	loff_t start = page_offset(page);
176	size_t len = PAGE_SIZE;
177	int ret;
178
179	memset(&cres, 0, sizeof(cres));
180	bvec[0].bv_page		= page;
181	bvec[0].bv_offset	= 0;
182	bvec[0].bv_len		= PAGE_SIZE;
183	iov_iter_bvec(&iter, ITER_SOURCE, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
184
185	ret = fscache_begin_write_operation(&cres, cookie);
186	if (ret < 0)
187		return ret;
188
189	ret = cres.ops->prepare_write(&cres, &start, &len, i_size_read(inode),
190				      no_space_allocated_yet);
191	if (ret == 0)
192		ret = fscache_write(&cres, page_offset(page), &iter, NULL, NULL);
193	fscache_end_operation(&cres);
194	return ret;
195}
196
197/*
198 * Retrieve a page from FS-Cache
199 */
200int __cifs_readpage_from_fscache(struct inode *inode, struct page *page)
201{
202	int ret;
203
204	cifs_dbg(FYI, "%s: (fsc:%p, p:%p, i:0x%p\n",
205		 __func__, cifs_inode_cookie(inode), page, inode);
206
207	ret = fscache_fallback_read_page(inode, page);
208	if (ret < 0)
209		return ret;
210
211	/* Read completed synchronously */
212	SetPageUptodate(page);
213	return 0;
214}
215
216void __cifs_readpage_to_fscache(struct inode *inode, struct page *page)
217{
218	cifs_dbg(FYI, "%s: (fsc: %p, p: %p, i: %p)\n",
219		 __func__, cifs_inode_cookie(inode), page, inode);
220
221	fscache_fallback_write_page(inode, page, true);
222}
223
224/*
225 * Query the cache occupancy.
226 */
227int __cifs_fscache_query_occupancy(struct inode *inode,
228				   pgoff_t first, unsigned int nr_pages,
229				   pgoff_t *_data_first,
230				   unsigned int *_data_nr_pages)
231{
232	struct netfs_cache_resources cres;
233	struct fscache_cookie *cookie = cifs_inode_cookie(inode);
234	loff_t start, data_start;
235	size_t len, data_len;
236	int ret;
237
238	ret = fscache_begin_read_operation(&cres, cookie);
239	if (ret < 0)
240		return ret;
241
242	start = first * PAGE_SIZE;
243	len = nr_pages * PAGE_SIZE;
244	ret = cres.ops->query_occupancy(&cres, start, len, PAGE_SIZE,
245					&data_start, &data_len);
246	if (ret == 0) {
247		*_data_first = data_start / PAGE_SIZE;
248		*_data_nr_pages = len / PAGE_SIZE;
249	}
250
251	fscache_end_operation(&cres);
252	return ret;
253}