1/*
2 * direct.c - NILFS direct block pointer.
3 *
4 * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
19 *
20 * Written by Koji Sato <koji@osrg.net>.
21 */
22
23#include <linux/errno.h>
24#include "nilfs.h"
25#include "page.h"
26#include "direct.h"
27#include "alloc.h"
28#include "dat.h"
29
30static inline __le64 *nilfs_direct_dptrs(const struct nilfs_bmap *direct)
31{
32	return (__le64 *)
33		((struct nilfs_direct_node *)direct->b_u.u_data + 1);
34}
35
36static inline __u64
37nilfs_direct_get_ptr(const struct nilfs_bmap *direct, __u64 key)
38{
39	return le64_to_cpu(*(nilfs_direct_dptrs(direct) + key));
40}
41
42static inline void nilfs_direct_set_ptr(struct nilfs_bmap *direct,
43					__u64 key, __u64 ptr)
44{
45	*(nilfs_direct_dptrs(direct) + key) = cpu_to_le64(ptr);
46}
47
48static int nilfs_direct_lookup(const struct nilfs_bmap *direct,
49			       __u64 key, int level, __u64 *ptrp)
50{
51	__u64 ptr;
52
53	if (key > NILFS_DIRECT_KEY_MAX || level != 1)
54		return -ENOENT;
55	ptr = nilfs_direct_get_ptr(direct, key);
56	if (ptr == NILFS_BMAP_INVALID_PTR)
57		return -ENOENT;
58
59	*ptrp = ptr;
60	return 0;
61}
62
63static int nilfs_direct_lookup_contig(const struct nilfs_bmap *direct,
64				      __u64 key, __u64 *ptrp,
65				      unsigned maxblocks)
66{
67	struct inode *dat = NULL;
68	__u64 ptr, ptr2;
69	sector_t blocknr;
70	int ret, cnt;
71
72	if (key > NILFS_DIRECT_KEY_MAX)
73		return -ENOENT;
74	ptr = nilfs_direct_get_ptr(direct, key);
75	if (ptr == NILFS_BMAP_INVALID_PTR)
76		return -ENOENT;
77
78	if (NILFS_BMAP_USE_VBN(direct)) {
79		dat = nilfs_bmap_get_dat(direct);
80		ret = nilfs_dat_translate(dat, ptr, &blocknr);
81		if (ret < 0)
82			return ret;
83		ptr = blocknr;
84	}
85
86	maxblocks = min_t(unsigned, maxblocks, NILFS_DIRECT_KEY_MAX - key + 1);
87	for (cnt = 1; cnt < maxblocks &&
88		     (ptr2 = nilfs_direct_get_ptr(direct, key + cnt)) !=
89		     NILFS_BMAP_INVALID_PTR;
90	     cnt++) {
91		if (dat) {
92			ret = nilfs_dat_translate(dat, ptr2, &blocknr);
93			if (ret < 0)
94				return ret;
95			ptr2 = blocknr;
96		}
97		if (ptr2 != ptr + cnt)
98			break;
99	}
100	*ptrp = ptr;
101	return cnt;
102}
103
104static __u64
105nilfs_direct_find_target_v(const struct nilfs_bmap *direct, __u64 key)
106{
107	__u64 ptr;
108
109	ptr = nilfs_bmap_find_target_seq(direct, key);
110	if (ptr != NILFS_BMAP_INVALID_PTR)
111		/* sequential access */
112		return ptr;
113	else
114		/* block group */
115		return nilfs_bmap_find_target_in_group(direct);
116}
117
118static int nilfs_direct_insert(struct nilfs_bmap *bmap, __u64 key, __u64 ptr)
119{
120	union nilfs_bmap_ptr_req req;
121	struct inode *dat = NULL;
122	struct buffer_head *bh;
123	int ret;
124
125	if (key > NILFS_DIRECT_KEY_MAX)
126		return -ENOENT;
127	if (nilfs_direct_get_ptr(bmap, key) != NILFS_BMAP_INVALID_PTR)
128		return -EEXIST;
129
130	if (NILFS_BMAP_USE_VBN(bmap)) {
131		req.bpr_ptr = nilfs_direct_find_target_v(bmap, key);
132		dat = nilfs_bmap_get_dat(bmap);
133	}
134	ret = nilfs_bmap_prepare_alloc_ptr(bmap, &req, dat);
135	if (!ret) {
136		/* ptr must be a pointer to a buffer head. */
137		bh = (struct buffer_head *)((unsigned long)ptr);
138		set_buffer_nilfs_volatile(bh);
139
140		nilfs_bmap_commit_alloc_ptr(bmap, &req, dat);
141		nilfs_direct_set_ptr(bmap, key, req.bpr_ptr);
142
143		if (!nilfs_bmap_dirty(bmap))
144			nilfs_bmap_set_dirty(bmap);
145
146		if (NILFS_BMAP_USE_VBN(bmap))
147			nilfs_bmap_set_target_v(bmap, key, req.bpr_ptr);
148
149		nilfs_bmap_add_blocks(bmap, 1);
150	}
151	return ret;
152}
153
154static int nilfs_direct_delete(struct nilfs_bmap *bmap, __u64 key)
155{
156	union nilfs_bmap_ptr_req req;
157	struct inode *dat;
158	int ret;
159
160	if (key > NILFS_DIRECT_KEY_MAX ||
161	    nilfs_direct_get_ptr(bmap, key) == NILFS_BMAP_INVALID_PTR)
162		return -ENOENT;
163
164	dat = NILFS_BMAP_USE_VBN(bmap) ? nilfs_bmap_get_dat(bmap) : NULL;
165	req.bpr_ptr = nilfs_direct_get_ptr(bmap, key);
166
167	ret = nilfs_bmap_prepare_end_ptr(bmap, &req, dat);
168	if (!ret) {
169		nilfs_bmap_commit_end_ptr(bmap, &req, dat);
170		nilfs_direct_set_ptr(bmap, key, NILFS_BMAP_INVALID_PTR);
171		nilfs_bmap_sub_blocks(bmap, 1);
172	}
173	return ret;
174}
175
176static int nilfs_direct_last_key(const struct nilfs_bmap *direct, __u64 *keyp)
177{
178	__u64 key, lastkey;
179
180	lastkey = NILFS_DIRECT_KEY_MAX + 1;
181	for (key = NILFS_DIRECT_KEY_MIN; key <= NILFS_DIRECT_KEY_MAX; key++)
182		if (nilfs_direct_get_ptr(direct, key) !=
183		    NILFS_BMAP_INVALID_PTR)
184			lastkey = key;
185
186	if (lastkey == NILFS_DIRECT_KEY_MAX + 1)
187		return -ENOENT;
188
189	*keyp = lastkey;
190
191	return 0;
192}
193
194static int nilfs_direct_check_insert(const struct nilfs_bmap *bmap, __u64 key)
195{
196	return key > NILFS_DIRECT_KEY_MAX;
197}
198
199static int nilfs_direct_gather_data(struct nilfs_bmap *direct,
200				    __u64 *keys, __u64 *ptrs, int nitems)
201{
202	__u64 key;
203	__u64 ptr;
204	int n;
205
206	if (nitems > NILFS_DIRECT_NBLOCKS)
207		nitems = NILFS_DIRECT_NBLOCKS;
208	n = 0;
209	for (key = 0; key < nitems; key++) {
210		ptr = nilfs_direct_get_ptr(direct, key);
211		if (ptr != NILFS_BMAP_INVALID_PTR) {
212			keys[n] = key;
213			ptrs[n] = ptr;
214			n++;
215		}
216	}
217	return n;
218}
219
220int nilfs_direct_delete_and_convert(struct nilfs_bmap *bmap,
221				    __u64 key, __u64 *keys, __u64 *ptrs, int n)
222{
223	__le64 *dptrs;
224	int ret, i, j;
225
226	/* no need to allocate any resource for conversion */
227
228	/* delete */
229	ret = bmap->b_ops->bop_delete(bmap, key);
230	if (ret < 0)
231		return ret;
232
233	/* free resources */
234	if (bmap->b_ops->bop_clear != NULL)
235		bmap->b_ops->bop_clear(bmap);
236
237	/* convert */
238	dptrs = nilfs_direct_dptrs(bmap);
239	for (i = 0, j = 0; i < NILFS_DIRECT_NBLOCKS; i++) {
240		if ((j < n) && (i == keys[j])) {
241			dptrs[i] = (i != key) ?
242				cpu_to_le64(ptrs[j]) :
243				NILFS_BMAP_INVALID_PTR;
244			j++;
245		} else
246			dptrs[i] = NILFS_BMAP_INVALID_PTR;
247	}
248
249	nilfs_direct_init(bmap);
250	return 0;
251}
252
253static int nilfs_direct_propagate(struct nilfs_bmap *bmap,
254				  struct buffer_head *bh)
255{
256	struct nilfs_palloc_req oldreq, newreq;
257	struct inode *dat;
258	__u64 key;
259	__u64 ptr;
260	int ret;
261
262	if (!NILFS_BMAP_USE_VBN(bmap))
263		return 0;
264
265	dat = nilfs_bmap_get_dat(bmap);
266	key = nilfs_bmap_data_get_key(bmap, bh);
267	ptr = nilfs_direct_get_ptr(bmap, key);
268	if (!buffer_nilfs_volatile(bh)) {
269		oldreq.pr_entry_nr = ptr;
270		newreq.pr_entry_nr = ptr;
271		ret = nilfs_dat_prepare_update(dat, &oldreq, &newreq);
272		if (ret < 0)
273			return ret;
274		nilfs_dat_commit_update(dat, &oldreq, &newreq,
275					bmap->b_ptr_type == NILFS_BMAP_PTR_VS);
276		set_buffer_nilfs_volatile(bh);
277		nilfs_direct_set_ptr(bmap, key, newreq.pr_entry_nr);
278	} else
279		ret = nilfs_dat_mark_dirty(dat, ptr);
280
281	return ret;
282}
283
284static int nilfs_direct_assign_v(struct nilfs_bmap *direct,
285				 __u64 key, __u64 ptr,
286				 struct buffer_head **bh,
287				 sector_t blocknr,
288				 union nilfs_binfo *binfo)
289{
290	struct inode *dat = nilfs_bmap_get_dat(direct);
291	union nilfs_bmap_ptr_req req;
292	int ret;
293
294	req.bpr_ptr = ptr;
295	ret = nilfs_dat_prepare_start(dat, &req.bpr_req);
296	if (!ret) {
297		nilfs_dat_commit_start(dat, &req.bpr_req, blocknr);
298		binfo->bi_v.bi_vblocknr = cpu_to_le64(ptr);
299		binfo->bi_v.bi_blkoff = cpu_to_le64(key);
300	}
301	return ret;
302}
303
304static int nilfs_direct_assign_p(struct nilfs_bmap *direct,
305				 __u64 key, __u64 ptr,
306				 struct buffer_head **bh,
307				 sector_t blocknr,
308				 union nilfs_binfo *binfo)
309{
310	nilfs_direct_set_ptr(direct, key, blocknr);
311
312	binfo->bi_dat.bi_blkoff = cpu_to_le64(key);
313	binfo->bi_dat.bi_level = 0;
314
315	return 0;
316}
317
318static int nilfs_direct_assign(struct nilfs_bmap *bmap,
319			       struct buffer_head **bh,
320			       sector_t blocknr,
321			       union nilfs_binfo *binfo)
322{
323	__u64 key;
324	__u64 ptr;
325
326	key = nilfs_bmap_data_get_key(bmap, *bh);
327	if (unlikely(key > NILFS_DIRECT_KEY_MAX)) {
328		printk(KERN_CRIT "%s: invalid key: %llu\n", __func__,
329		       (unsigned long long)key);
330		return -EINVAL;
331	}
332	ptr = nilfs_direct_get_ptr(bmap, key);
333	if (unlikely(ptr == NILFS_BMAP_INVALID_PTR)) {
334		printk(KERN_CRIT "%s: invalid pointer: %llu\n", __func__,
335		       (unsigned long long)ptr);
336		return -EINVAL;
337	}
338
339	return NILFS_BMAP_USE_VBN(bmap) ?
340		nilfs_direct_assign_v(bmap, key, ptr, bh, blocknr, binfo) :
341		nilfs_direct_assign_p(bmap, key, ptr, bh, blocknr, binfo);
342}
343
344static const struct nilfs_bmap_operations nilfs_direct_ops = {
345	.bop_lookup		=	nilfs_direct_lookup,
346	.bop_lookup_contig	=	nilfs_direct_lookup_contig,
347	.bop_insert		=	nilfs_direct_insert,
348	.bop_delete		=	nilfs_direct_delete,
349	.bop_clear		=	NULL,
350
351	.bop_propagate		=	nilfs_direct_propagate,
352
353	.bop_lookup_dirty_buffers	=	NULL,
354
355	.bop_assign		=	nilfs_direct_assign,
356	.bop_mark		=	NULL,
357
358	.bop_last_key		=	nilfs_direct_last_key,
359	.bop_check_insert	=	nilfs_direct_check_insert,
360	.bop_check_delete	=	NULL,
361	.bop_gather_data	=	nilfs_direct_gather_data,
362};
363
364
365int nilfs_direct_init(struct nilfs_bmap *bmap)
366{
367	bmap->b_ops = &nilfs_direct_ops;
368	return 0;
369}
370