1/*
  2 *   fs/cifs/fscache.c - CIFS filesystem cache interface
  3 *
  4 *   Copyright (c) 2010 Novell, Inc.
  5 *   Author(s): Suresh Jayaraman <sjayaraman@suse.de>
  6 *
  7 *   This library is free software; you can redistribute it and/or modify
  8 *   it under the terms of the GNU Lesser General Public License as published
  9 *   by the Free Software Foundation; either version 2.1 of the License, or
 10 *   (at your option) any later version.
 11 *
 12 *   This library is distributed in the hope that it will be useful,
 13 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 14 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 15 *   the GNU Lesser General Public License for more details.
 16 *
 17 *   You should have received a copy of the GNU Lesser General Public License
 18 *   along with this library; if not, write to the Free Software
 19 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 20 */
 21#include "fscache.h"
 22#include "cifsglob.h"
 23#include "cifs_debug.h"
 24#include "cifs_fs_sb.h"
 25
 26void cifs_fscache_get_client_cookie(struct TCP_Server_Info *server)
 27{
 28	server->fscache =
 29		fscache_acquire_cookie(cifs_fscache_netfs.primary_index,
 30				&cifs_fscache_server_index_def, server);
 31	cFYI(1, "%s: (0x%p/0x%p)", __func__, server,
 32			server->fscache);
 33}
 34
 35void cifs_fscache_release_client_cookie(struct TCP_Server_Info *server)
 36{
 37	cFYI(1, "%s: (0x%p/0x%p)", __func__, server,
 38			server->fscache);
 39	fscache_relinquish_cookie(server->fscache, 0);
 40	server->fscache = NULL;
 41}
 42
 43void cifs_fscache_get_super_cookie(struct cifs_tcon *tcon)
 44{
 45	struct TCP_Server_Info *server = tcon->ses->server;
 46
 47	tcon->fscache =
 48		fscache_acquire_cookie(server->fscache,
 49				&cifs_fscache_super_index_def, tcon);
 50	cFYI(1, "%s: (0x%p/0x%p)", __func__, server->fscache,
 51			tcon->fscache);
 52}
 53
 54void cifs_fscache_release_super_cookie(struct cifs_tcon *tcon)
 55{
 56	cFYI(1, "%s: (0x%p)", __func__, tcon->fscache);
 57	fscache_relinquish_cookie(tcon->fscache, 0);
 58	tcon->fscache = NULL;
 59}
 60
 61static void cifs_fscache_enable_inode_cookie(struct inode *inode)
 62{
 63	struct cifsInodeInfo *cifsi = CIFS_I(inode);
 64	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 65	struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
 66
 67	if (cifsi->fscache)
 68		return;
 69
 70	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_FSCACHE) {
 71		cifsi->fscache = fscache_acquire_cookie(tcon->fscache,
 72				&cifs_fscache_inode_object_def, cifsi);
 73		cFYI(1, "%s: got FH cookie (0x%p/0x%p)", __func__,
 74				tcon->fscache, cifsi->fscache);
 75	}
 76}
 77
 78void cifs_fscache_release_inode_cookie(struct inode *inode)
 79{
 80	struct cifsInodeInfo *cifsi = CIFS_I(inode);
 81
 82	if (cifsi->fscache) {
 83		cFYI(1, "%s: (0x%p)", __func__, cifsi->fscache);
 84		fscache_relinquish_cookie(cifsi->fscache, 0);
 85		cifsi->fscache = NULL;
 86	}
 87}
 88
 89static void cifs_fscache_disable_inode_cookie(struct inode *inode)
 90{
 91	struct cifsInodeInfo *cifsi = CIFS_I(inode);
 92
 93	if (cifsi->fscache) {
 94		cFYI(1, "%s: (0x%p)", __func__, cifsi->fscache);
 95		fscache_uncache_all_inode_pages(cifsi->fscache, inode);
 96		fscache_relinquish_cookie(cifsi->fscache, 1);
 97		cifsi->fscache = NULL;
 98	}
 99}
100
101void cifs_fscache_set_inode_cookie(struct inode *inode, struct file *filp)
102{
103	if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
104		cifs_fscache_disable_inode_cookie(inode);
105	else
106		cifs_fscache_enable_inode_cookie(inode);
107}
108
109void cifs_fscache_reset_inode_cookie(struct inode *inode)
110{
111	struct cifsInodeInfo *cifsi = CIFS_I(inode);
112	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
113	struct fscache_cookie *old = cifsi->fscache;
114
115	if (cifsi->fscache) {
116		/* retire the current fscache cache and get a new one */
117		fscache_relinquish_cookie(cifsi->fscache, 1);
118
119		cifsi->fscache = fscache_acquire_cookie(
120					cifs_sb_master_tcon(cifs_sb)->fscache,
121					&cifs_fscache_inode_object_def,
122					cifsi);
123		cFYI(1, "%s: new cookie 0x%p oldcookie 0x%p",
124				__func__, cifsi->fscache, old);
125	}
126}
127
128int cifs_fscache_release_page(struct page *page, gfp_t gfp)
129{
130	if (PageFsCache(page)) {
131		struct inode *inode = page->mapping->host;
132		struct cifsInodeInfo *cifsi = CIFS_I(inode);
133
134		cFYI(1, "%s: (0x%p/0x%p)", __func__, page,
135				cifsi->fscache);
136		if (!fscache_maybe_release_page(cifsi->fscache, page, gfp))
137			return 0;
138	}
139
140	return 1;
141}
142
143static void cifs_readpage_from_fscache_complete(struct page *page, void *ctx,
144						int error)
145{
146	cFYI(1, "%s: (0x%p/%d)", __func__, page, error);
147	if (!error)
148		SetPageUptodate(page);
149	unlock_page(page);
150}
151
152/*
153 * Retrieve a page from FS-Cache
154 */
155int __cifs_readpage_from_fscache(struct inode *inode, struct page *page)
156{
157	int ret;
158
159	cFYI(1, "%s: (fsc:%p, p:%p, i:0x%p", __func__,
160			CIFS_I(inode)->fscache, page, inode);
161	ret = fscache_read_or_alloc_page(CIFS_I(inode)->fscache, page,
162					 cifs_readpage_from_fscache_complete,
163					 NULL,
164					 GFP_KERNEL);
165	switch (ret) {
166
167	case 0: /* page found in fscache, read submitted */
168		cFYI(1, "%s: submitted", __func__);
169		return ret;
170	case -ENOBUFS:	/* page won't be cached */
171	case -ENODATA:	/* page not in cache */
172		cFYI(1, "%s: %d", __func__, ret);
173		return 1;
174
175	default:
176		cERROR(1, "unknown error ret = %d", ret);
177	}
178	return ret;
179}
180
181/*
182 * Retrieve a set of pages from FS-Cache
183 */
184int __cifs_readpages_from_fscache(struct inode *inode,
185				struct address_space *mapping,
186				struct list_head *pages,
187				unsigned *nr_pages)
188{
189	int ret;
190
191	cFYI(1, "%s: (0x%p/%u/0x%p)", __func__,
192			CIFS_I(inode)->fscache, *nr_pages, inode);
193	ret = fscache_read_or_alloc_pages(CIFS_I(inode)->fscache, mapping,
194					  pages, nr_pages,
195					  cifs_readpage_from_fscache_complete,
196					  NULL,
197					  mapping_gfp_mask(mapping));
198	switch (ret) {
199	case 0:	/* read submitted to the cache for all pages */
200		cFYI(1, "%s: submitted", __func__);
201		return ret;
202
203	case -ENOBUFS:	/* some pages are not cached and can't be */
204	case -ENODATA:	/* some pages are not cached */
205		cFYI(1, "%s: no page", __func__);
206		return 1;
207
208	default:
209		cFYI(1, "unknown error ret = %d", ret);
210	}
211
212	return ret;
213}
214
215void __cifs_readpage_to_fscache(struct inode *inode, struct page *page)
216{
217	int ret;
218
219	cFYI(1, "%s: (fsc: %p, p: %p, i: %p)", __func__,
220			CIFS_I(inode)->fscache, page, inode);
221	ret = fscache_write_page(CIFS_I(inode)->fscache, page, GFP_KERNEL);
222	if (ret != 0)
223		fscache_uncache_page(CIFS_I(inode)->fscache, page);
224}
225
226void __cifs_fscache_invalidate_page(struct page *page, struct inode *inode)
227{
228	struct cifsInodeInfo *cifsi = CIFS_I(inode);
229	struct fscache_cookie *cookie = cifsi->fscache;
230
231	cFYI(1, "%s: (0x%p/0x%p)", __func__, page, cookie);
232	fscache_wait_on_page_write(cookie, page);
233	fscache_uncache_page(cookie, page);
234}
235