xref: /kernel/linux/linux-5.10/fs/ceph/cache.c (revision 8c2ecf20) 
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Ceph cache definitions.
4 *
5 *  Copyright (C) 2013 by Adfin Solutions, Inc. All Rights Reserved.
6 *  Written by Milosz Tanski (milosz@adfin.com)
7 */
8
9#include <linux/ceph/ceph_debug.h>
10
11#include <linux/fs_context.h>
12#include "super.h"
13#include "cache.h"
14
15struct ceph_aux_inode {
16	u64 	version;
17	u64	mtime_sec;
18	u64	mtime_nsec;
19};
20
21struct fscache_netfs ceph_cache_netfs = {
22	.name		= "ceph",
23	.version	= 0,
24};
25
26static DEFINE_MUTEX(ceph_fscache_lock);
27static LIST_HEAD(ceph_fscache_list);
28
29struct ceph_fscache_entry {
30	struct list_head list;
31	struct fscache_cookie *fscache;
32	size_t uniq_len;
33	/* The following members must be last */
34	struct ceph_fsid fsid;
35	char uniquifier[];
36};
37
38static const struct fscache_cookie_def ceph_fscache_fsid_object_def = {
39	.name		= "CEPH.fsid",
40	.type		= FSCACHE_COOKIE_TYPE_INDEX,
41};
42
43int __init ceph_fscache_register(void)
44{
45	return fscache_register_netfs(&ceph_cache_netfs);
46}
47
48void ceph_fscache_unregister(void)
49{
50	fscache_unregister_netfs(&ceph_cache_netfs);
51}
52
53int ceph_fscache_register_fs(struct ceph_fs_client* fsc, struct fs_context *fc)
54{
55	const struct ceph_fsid *fsid = &fsc->client->fsid;
56	const char *fscache_uniq = fsc->mount_options->fscache_uniq;
57	size_t uniq_len = fscache_uniq ? strlen(fscache_uniq) : 0;
58	struct ceph_fscache_entry *ent;
59	int err = 0;
60
61	mutex_lock(&ceph_fscache_lock);
62	list_for_each_entry(ent, &ceph_fscache_list, list) {
63		if (memcmp(&ent->fsid, fsid, sizeof(*fsid)))
64			continue;
65		if (ent->uniq_len != uniq_len)
66			continue;
67		if (uniq_len && memcmp(ent->uniquifier, fscache_uniq, uniq_len))
68			continue;
69
70		errorfc(fc, "fscache cookie already registered for fsid %pU, use fsc=<uniquifier> option",
71		       fsid);
72		err = -EBUSY;
73		goto out_unlock;
74	}
75
76	ent = kzalloc(sizeof(*ent) + uniq_len, GFP_KERNEL);
77	if (!ent) {
78		err = -ENOMEM;
79		goto out_unlock;
80	}
81
82	memcpy(&ent->fsid, fsid, sizeof(*fsid));
83	if (uniq_len > 0) {
84		memcpy(&ent->uniquifier, fscache_uniq, uniq_len);
85		ent->uniq_len = uniq_len;
86	}
87
88	fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index,
89					      &ceph_fscache_fsid_object_def,
90					      &ent->fsid, sizeof(ent->fsid) + uniq_len,
91					      NULL, 0,
92					      fsc, 0, true);
93
94	if (fsc->fscache) {
95		ent->fscache = fsc->fscache;
96		list_add_tail(&ent->list, &ceph_fscache_list);
97	} else {
98		kfree(ent);
99		errorfc(fc, "unable to register fscache cookie for fsid %pU",
100		       fsid);
101		/* all other fs ignore this error */
102	}
103out_unlock:
104	mutex_unlock(&ceph_fscache_lock);
105	return err;
106}
107
108static enum fscache_checkaux ceph_fscache_inode_check_aux(
109	void *cookie_netfs_data, const void *data, uint16_t dlen,
110	loff_t object_size)
111{
112	struct ceph_aux_inode aux;
113	struct ceph_inode_info* ci = cookie_netfs_data;
114	struct inode* inode = &ci->vfs_inode;
115
116	if (dlen != sizeof(aux) ||
117	    i_size_read(inode) != object_size)
118		return FSCACHE_CHECKAUX_OBSOLETE;
119
120	memset(&aux, 0, sizeof(aux));
121	aux.version = ci->i_version;
122	aux.mtime_sec = inode->i_mtime.tv_sec;
123	aux.mtime_nsec = inode->i_mtime.tv_nsec;
124
125	if (memcmp(data, &aux, sizeof(aux)) != 0)
126		return FSCACHE_CHECKAUX_OBSOLETE;
127
128	dout("ceph inode 0x%p cached okay\n", ci);
129	return FSCACHE_CHECKAUX_OKAY;
130}
131
132static const struct fscache_cookie_def ceph_fscache_inode_object_def = {
133	.name		= "CEPH.inode",
134	.type		= FSCACHE_COOKIE_TYPE_DATAFILE,
135	.check_aux	= ceph_fscache_inode_check_aux,
136};
137
138void ceph_fscache_register_inode_cookie(struct inode *inode)
139{
140	struct ceph_inode_info *ci = ceph_inode(inode);
141	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
142	struct ceph_aux_inode aux;
143
144	/* No caching for filesystem */
145	if (!fsc->fscache)
146		return;
147
148	/* Only cache for regular files that are read only */
149	if (!S_ISREG(inode->i_mode))
150		return;
151
152	inode_lock_nested(inode, I_MUTEX_CHILD);
153	if (!ci->fscache) {
154		memset(&aux, 0, sizeof(aux));
155		aux.version = ci->i_version;
156		aux.mtime_sec = inode->i_mtime.tv_sec;
157		aux.mtime_nsec = inode->i_mtime.tv_nsec;
158		ci->fscache = fscache_acquire_cookie(fsc->fscache,
159						     &ceph_fscache_inode_object_def,
160						     &ci->i_vino, sizeof(ci->i_vino),
161						     &aux, sizeof(aux),
162						     ci, i_size_read(inode), false);
163	}
164	inode_unlock(inode);
165}
166
167void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
168{
169	struct fscache_cookie* cookie;
170
171	if ((cookie = ci->fscache) == NULL)
172		return;
173
174	ci->fscache = NULL;
175
176	fscache_uncache_all_inode_pages(cookie, &ci->vfs_inode);
177	fscache_relinquish_cookie(cookie, &ci->i_vino, false);
178}
179
180static bool ceph_fscache_can_enable(void *data)
181{
182	struct inode *inode = data;
183	return !inode_is_open_for_write(inode);
184}
185
186void ceph_fscache_file_set_cookie(struct inode *inode, struct file *filp)
187{
188	struct ceph_inode_info *ci = ceph_inode(inode);
189
190	if (!fscache_cookie_valid(ci->fscache))
191		return;
192
193	if (inode_is_open_for_write(inode)) {
194		dout("fscache_file_set_cookie %p %p disabling cache\n",
195		     inode, filp);
196		fscache_disable_cookie(ci->fscache, &ci->i_vino, false);
197		fscache_uncache_all_inode_pages(ci->fscache, inode);
198	} else {
199		fscache_enable_cookie(ci->fscache, &ci->i_vino, i_size_read(inode),
200				      ceph_fscache_can_enable, inode);
201		if (fscache_cookie_enabled(ci->fscache)) {
202			dout("fscache_file_set_cookie %p %p enabling cache\n",
203			     inode, filp);
204		}
205	}
206}
207
208static void ceph_readpage_from_fscache_complete(struct page *page, void *data, int error)
209{
210	if (!error)
211		SetPageUptodate(page);
212
213	unlock_page(page);
214}
215
216static inline bool cache_valid(struct ceph_inode_info *ci)
217{
218	return ci->i_fscache_gen == ci->i_rdcache_gen;
219}
220
221
222/* Atempt to read from the fscache,
223 *
224 * This function is called from the readpage_nounlock context. DO NOT attempt to
225 * unlock the page here (or in the callback).
226 */
227int ceph_readpage_from_fscache(struct inode *inode, struct page *page)
228{
229	struct ceph_inode_info *ci = ceph_inode(inode);
230	int ret;
231
232	if (!cache_valid(ci))
233		return -ENOBUFS;
234
235	ret = fscache_read_or_alloc_page(ci->fscache, page,
236					 ceph_readpage_from_fscache_complete, NULL,
237					 GFP_KERNEL);
238
239	switch (ret) {
240		case 0: /* Page found */
241			dout("page read submitted\n");
242			return 0;
243		case -ENOBUFS: /* Pages were not found, and can't be */
244		case -ENODATA: /* Pages were not found */
245			dout("page/inode not in cache\n");
246			return ret;
247		default:
248			dout("%s: unknown error ret = %i\n", __func__, ret);
249			return ret;
250	}
251}
252
253int ceph_readpages_from_fscache(struct inode *inode,
254				  struct address_space *mapping,
255				  struct list_head *pages,
256				  unsigned *nr_pages)
257{
258	struct ceph_inode_info *ci = ceph_inode(inode);
259	int ret;
260
261	if (!cache_valid(ci))
262		return -ENOBUFS;
263
264	ret = fscache_read_or_alloc_pages(ci->fscache, mapping, pages, nr_pages,
265					  ceph_readpage_from_fscache_complete,
266					  NULL, mapping_gfp_mask(mapping));
267
268	switch (ret) {
269		case 0: /* All pages found */
270			dout("all-page read submitted\n");
271			return 0;
272		case -ENOBUFS: /* Some pages were not found, and can't be */
273		case -ENODATA: /* some pages were not found */
274			dout("page/inode not in cache\n");
275			return ret;
276		default:
277			dout("%s: unknown error ret = %i\n", __func__, ret);
278			return ret;
279	}
280}
281
282void ceph_readpage_to_fscache(struct inode *inode, struct page *page)
283{
284	struct ceph_inode_info *ci = ceph_inode(inode);
285	int ret;
286
287	if (!PageFsCache(page))
288		return;
289
290	if (!cache_valid(ci))
291		return;
292
293	ret = fscache_write_page(ci->fscache, page, i_size_read(inode),
294				 GFP_KERNEL);
295	if (ret)
296		 fscache_uncache_page(ci->fscache, page);
297}
298
299void ceph_invalidate_fscache_page(struct inode* inode, struct page *page)
300{
301	struct ceph_inode_info *ci = ceph_inode(inode);
302
303	if (!PageFsCache(page))
304		return;
305
306	fscache_wait_on_page_write(ci->fscache, page);
307	fscache_uncache_page(ci->fscache, page);
308}
309
310void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
311{
312	if (fscache_cookie_valid(fsc->fscache)) {
313		struct ceph_fscache_entry *ent;
314		bool found = false;
315
316		mutex_lock(&ceph_fscache_lock);
317		list_for_each_entry(ent, &ceph_fscache_list, list) {
318			if (ent->fscache == fsc->fscache) {
319				list_del(&ent->list);
320				kfree(ent);
321				found = true;
322				break;
323			}
324		}
325		WARN_ON_ONCE(!found);
326		mutex_unlock(&ceph_fscache_lock);
327
328		__fscache_relinquish_cookie(fsc->fscache, NULL, false);
329	}
330	fsc->fscache = NULL;
331}
332
333/*
334 * caller should hold CEPH_CAP_FILE_{RD,CACHE}
335 */
336void ceph_fscache_revalidate_cookie(struct ceph_inode_info *ci)
337{
338	if (cache_valid(ci))
339		return;
340
341	/* resue i_truncate_mutex. There should be no pending
342	 * truncate while the caller holds CEPH_CAP_FILE_RD */
343	mutex_lock(&ci->i_truncate_mutex);
344	if (!cache_valid(ci)) {
345		if (fscache_check_consistency(ci->fscache, &ci->i_vino))
346			fscache_invalidate(ci->fscache);
347		spin_lock(&ci->i_ceph_lock);
348		ci->i_fscache_gen = ci->i_rdcache_gen;
349		spin_unlock(&ci->i_ceph_lock);
350	}
351	mutex_unlock(&ci->i_truncate_mutex);
352}
353