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_inode_add_blocks(bmap->b_inode, 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_inode_sub_blocks(bmap->b_inode, 1);
172	}
173	return ret;
174}
175
176static int nilfs_direct_seek_key(const struct nilfs_bmap *direct, __u64 start,
177				 __u64 *keyp)
178{
179	__u64 key;
180
181	for (key = start; key <= NILFS_DIRECT_KEY_MAX; key++) {
182		if (nilfs_direct_get_ptr(direct, key) !=
183		    NILFS_BMAP_INVALID_PTR) {
184			*keyp = key;
185			return 0;
186		}
187	}
188	return -ENOENT;
189}
190
191static int nilfs_direct_last_key(const struct nilfs_bmap *direct, __u64 *keyp)
192{
193	__u64 key, lastkey;
194
195	lastkey = NILFS_DIRECT_KEY_MAX + 1;
196	for (key = NILFS_DIRECT_KEY_MIN; key <= NILFS_DIRECT_KEY_MAX; key++)
197		if (nilfs_direct_get_ptr(direct, key) !=
198		    NILFS_BMAP_INVALID_PTR)
199			lastkey = key;
200
201	if (lastkey == NILFS_DIRECT_KEY_MAX + 1)
202		return -ENOENT;
203
204	*keyp = lastkey;
205
206	return 0;
207}
208
209static int nilfs_direct_check_insert(const struct nilfs_bmap *bmap, __u64 key)
210{
211	return key > NILFS_DIRECT_KEY_MAX;
212}
213
214static int nilfs_direct_gather_data(struct nilfs_bmap *direct,
215				    __u64 *keys, __u64 *ptrs, int nitems)
216{
217	__u64 key;
218	__u64 ptr;
219	int n;
220
221	if (nitems > NILFS_DIRECT_NBLOCKS)
222		nitems = NILFS_DIRECT_NBLOCKS;
223	n = 0;
224	for (key = 0; key < nitems; key++) {
225		ptr = nilfs_direct_get_ptr(direct, key);
226		if (ptr != NILFS_BMAP_INVALID_PTR) {
227			keys[n] = key;
228			ptrs[n] = ptr;
229			n++;
230		}
231	}
232	return n;
233}
234
235int nilfs_direct_delete_and_convert(struct nilfs_bmap *bmap,
236				    __u64 key, __u64 *keys, __u64 *ptrs, int n)
237{
238	__le64 *dptrs;
239	int ret, i, j;
240
241	/* no need to allocate any resource for conversion */
242
243	/* delete */
244	ret = bmap->b_ops->bop_delete(bmap, key);
245	if (ret < 0)
246		return ret;
247
248	/* free resources */
249	if (bmap->b_ops->bop_clear != NULL)
250		bmap->b_ops->bop_clear(bmap);
251
252	/* convert */
253	dptrs = nilfs_direct_dptrs(bmap);
254	for (i = 0, j = 0; i < NILFS_DIRECT_NBLOCKS; i++) {
255		if ((j < n) && (i == keys[j])) {
256			dptrs[i] = (i != key) ?
257				cpu_to_le64(ptrs[j]) :
258				NILFS_BMAP_INVALID_PTR;
259			j++;
260		} else
261			dptrs[i] = NILFS_BMAP_INVALID_PTR;
262	}
263
264	nilfs_direct_init(bmap);
265	return 0;
266}
267
268static int nilfs_direct_propagate(struct nilfs_bmap *bmap,
269				  struct buffer_head *bh)
270{
271	struct nilfs_palloc_req oldreq, newreq;
272	struct inode *dat;
273	__u64 key;
274	__u64 ptr;
275	int ret;
276
277	if (!NILFS_BMAP_USE_VBN(bmap))
278		return 0;
279
280	dat = nilfs_bmap_get_dat(bmap);
281	key = nilfs_bmap_data_get_key(bmap, bh);
282	ptr = nilfs_direct_get_ptr(bmap, key);
283	if (!buffer_nilfs_volatile(bh)) {
284		oldreq.pr_entry_nr = ptr;
285		newreq.pr_entry_nr = ptr;
286		ret = nilfs_dat_prepare_update(dat, &oldreq, &newreq);
287		if (ret < 0)
288			return ret;
289		nilfs_dat_commit_update(dat, &oldreq, &newreq,
290					bmap->b_ptr_type == NILFS_BMAP_PTR_VS);
291		set_buffer_nilfs_volatile(bh);
292		nilfs_direct_set_ptr(bmap, key, newreq.pr_entry_nr);
293	} else
294		ret = nilfs_dat_mark_dirty(dat, ptr);
295
296	return ret;
297}
298
299static int nilfs_direct_assign_v(struct nilfs_bmap *direct,
300				 __u64 key, __u64 ptr,
301				 struct buffer_head **bh,
302				 sector_t blocknr,
303				 union nilfs_binfo *binfo)
304{
305	struct inode *dat = nilfs_bmap_get_dat(direct);
306	union nilfs_bmap_ptr_req req;
307	int ret;
308
309	req.bpr_ptr = ptr;
310	ret = nilfs_dat_prepare_start(dat, &req.bpr_req);
311	if (!ret) {
312		nilfs_dat_commit_start(dat, &req.bpr_req, blocknr);
313		binfo->bi_v.bi_vblocknr = cpu_to_le64(ptr);
314		binfo->bi_v.bi_blkoff = cpu_to_le64(key);
315	}
316	return ret;
317}
318
319static int nilfs_direct_assign_p(struct nilfs_bmap *direct,
320				 __u64 key, __u64 ptr,
321				 struct buffer_head **bh,
322				 sector_t blocknr,
323				 union nilfs_binfo *binfo)
324{
325	nilfs_direct_set_ptr(direct, key, blocknr);
326
327	binfo->bi_dat.bi_blkoff = cpu_to_le64(key);
328	binfo->bi_dat.bi_level = 0;
329
330	return 0;
331}
332
333static int nilfs_direct_assign(struct nilfs_bmap *bmap,
334			       struct buffer_head **bh,
335			       sector_t blocknr,
336			       union nilfs_binfo *binfo)
337{
338	__u64 key;
339	__u64 ptr;
340
341	key = nilfs_bmap_data_get_key(bmap, *bh);
342	if (unlikely(key > NILFS_DIRECT_KEY_MAX)) {
343		printk(KERN_CRIT "%s: invalid key: %llu\n", __func__,
344		       (unsigned long long)key);
345		return -EINVAL;
346	}
347	ptr = nilfs_direct_get_ptr(bmap, key);
348	if (unlikely(ptr == NILFS_BMAP_INVALID_PTR)) {
349		printk(KERN_CRIT "%s: invalid pointer: %llu\n", __func__,
350		       (unsigned long long)ptr);
351		return -EINVAL;
352	}
353
354	return NILFS_BMAP_USE_VBN(bmap) ?
355		nilfs_direct_assign_v(bmap, key, ptr, bh, blocknr, binfo) :
356		nilfs_direct_assign_p(bmap, key, ptr, bh, blocknr, binfo);
357}
358
359static const struct nilfs_bmap_operations nilfs_direct_ops = {
360	.bop_lookup		=	nilfs_direct_lookup,
361	.bop_lookup_contig	=	nilfs_direct_lookup_contig,
362	.bop_insert		=	nilfs_direct_insert,
363	.bop_delete		=	nilfs_direct_delete,
364	.bop_clear		=	NULL,
365
366	.bop_propagate		=	nilfs_direct_propagate,
367
368	.bop_lookup_dirty_buffers	=	NULL,
369
370	.bop_assign		=	nilfs_direct_assign,
371	.bop_mark		=	NULL,
372
373	.bop_seek_key		=	nilfs_direct_seek_key,
374	.bop_last_key		=	nilfs_direct_last_key,
375
376	.bop_check_insert	=	nilfs_direct_check_insert,
377	.bop_check_delete	=	NULL,
378	.bop_gather_data	=	nilfs_direct_gather_data,
379};
380
381
382int nilfs_direct_init(struct nilfs_bmap *bmap)
383{
384	bmap->b_ops = &nilfs_direct_ops;
385	return 0;
386}
387