1 /*
2 * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
3 *
4 * Copyright (C) 2002-2011 Aleph One Ltd.
5 * for Toby Churchill Ltd and Brightstar Engineering
6 *
7 * Created by Charles Manning <charles@aleph1.co.uk>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 */
13
14 /* Summaries write the useful part of the tags for the chunks in a block into an
15 * an array which is written to the last n chunks of the block.
16 * Reading the summaries gives all the tags for the block in one read. Much
17 * faster.
18 *
19 * Chunks holding summaries are marked with tags making it look like
20 * they are part of a fake file.
21 *
22 * The summary could also be used during gc.
23 *
24 */
25
26 #include "yaffs_summary.h"
27 #include "yaffs_packedtags2.h"
28 #include "yaffs_nand.h"
29 #include "yaffs_getblockinfo.h"
30 #include "yaffs_bitmap.h"
31
32 /*
33 * The summary is built up in an array of summary tags.
34 * This gets written to the last one or two (maybe more) chunks in a block.
35 * A summary header is written as the first part of each chunk of summary data.
36 * The summary header must match or the summary is rejected.
37 */
38
39 /* Summary tags don't need the sequence number because that is redundant. */
40 struct yaffs_summary_tags {
41 unsigned obj_id;
42 unsigned chunk_id;
43 unsigned n_bytes;
44 };
45
46 /* Summary header */
47 struct yaffs_summary_header {
48 unsigned version; /* Must match current version */
49 unsigned block; /* Must be this block */
50 unsigned seq; /* Must be this sequence number */
51 unsigned sum; /* Just add up all the bytes in the tags */
52 };
53
54
yaffs_summary_clear(struct yaffs_dev * dev)55 static void yaffs_summary_clear(struct yaffs_dev *dev)
56 {
57 if (!dev->sum_tags)
58 return;
59 memset(dev->sum_tags, 0, dev->chunks_per_summary *
60 sizeof(struct yaffs_summary_tags));
61 }
62
63
yaffs_summary_deinit(struct yaffs_dev * dev)64 void yaffs_summary_deinit(struct yaffs_dev *dev)
65 {
66 kfree(dev->sum_tags);
67 dev->sum_tags = NULL;
68 kfree(dev->gc_sum_tags);
69 dev->gc_sum_tags = NULL;
70 dev->chunks_per_summary = 0;
71 }
72
yaffs_summary_init(struct yaffs_dev * dev)73 int yaffs_summary_init(struct yaffs_dev *dev)
74 {
75 int sum_bytes;
76 int chunks_used; /* Number of chunks used by summary */
77 int sum_tags_bytes;
78
79 sum_bytes = dev->param.chunks_per_block *
80 sizeof(struct yaffs_summary_tags);
81
82 chunks_used = (sum_bytes + dev->data_bytes_per_chunk - 1)/
83 (dev->data_bytes_per_chunk -
84 sizeof(struct yaffs_summary_header));
85
86 dev->chunks_per_summary = dev->param.chunks_per_block - chunks_used;
87 sum_tags_bytes = sizeof(struct yaffs_summary_tags) *
88 dev->chunks_per_summary;
89 dev->sum_tags = kmalloc(sum_tags_bytes, GFP_NOFS);
90 dev->gc_sum_tags = kmalloc(sum_tags_bytes, GFP_NOFS);
91 if (!dev->sum_tags || !dev->gc_sum_tags) {
92 yaffs_summary_deinit(dev);
93 return YAFFS_FAIL;
94 }
95
96 yaffs_summary_clear(dev);
97
98 return YAFFS_OK;
99 }
100
yaffs_summary_sum(struct yaffs_dev * dev)101 static unsigned yaffs_summary_sum(struct yaffs_dev *dev)
102 {
103 u8 *sum_buffer = (u8 *)dev->sum_tags;
104 int i;
105 unsigned sum = 0;
106
107 i = sizeof(struct yaffs_summary_tags) *
108 dev->chunks_per_summary;
109 while (i > 0) {
110 sum += *sum_buffer;
111 sum_buffer++;
112 i--;
113 }
114
115 return sum;
116 }
117
yaffs_summary_write(struct yaffs_dev * dev,int blk)118 static int yaffs_summary_write(struct yaffs_dev *dev, int blk)
119 {
120 struct yaffs_ext_tags tags;
121 u8 *buffer;
122 u8 *sum_buffer = (u8 *)dev->sum_tags;
123 int n_bytes;
124 int chunk_in_nand;
125 int chunk_in_block;
126 int result;
127 int this_tx;
128 struct yaffs_summary_header hdr;
129 int sum_bytes_per_chunk = dev->data_bytes_per_chunk - sizeof(hdr);
130 struct yaffs_block_info *bi = yaffs_get_block_info(dev, blk);
131
132 buffer = yaffs_get_temp_buffer(dev);
133 n_bytes = sizeof(struct yaffs_summary_tags) *
134 dev->chunks_per_summary;
135 memset(&tags, 0, sizeof(struct yaffs_ext_tags));
136 tags.obj_id = YAFFS_OBJECTID_SUMMARY;
137 tags.chunk_id = 1;
138 chunk_in_block = dev->chunks_per_summary;
139 chunk_in_nand = dev->alloc_block * dev->param.chunks_per_block +
140 dev->chunks_per_summary;
141 hdr.version = YAFFS_SUMMARY_VERSION;
142 hdr.block = blk;
143 hdr.seq = bi->seq_number;
144 hdr.sum = yaffs_summary_sum(dev);
145
146 do {
147 this_tx = n_bytes;
148 if (this_tx > sum_bytes_per_chunk)
149 this_tx = sum_bytes_per_chunk;
150 memcpy(buffer, &hdr, sizeof(hdr));
151 memcpy(buffer + sizeof(hdr), sum_buffer, this_tx);
152 tags.n_bytes = this_tx + sizeof(hdr);
153 result = yaffs_wr_chunk_tags_nand(dev, chunk_in_nand,
154 buffer, &tags);
155
156 if (result != YAFFS_OK)
157 break;
158 yaffs_set_chunk_bit(dev, blk, chunk_in_block);
159 bi->pages_in_use++;
160 dev->n_free_chunks--;
161
162 n_bytes -= this_tx;
163 sum_buffer += this_tx;
164 chunk_in_nand++;
165 chunk_in_block++;
166 tags.chunk_id++;
167 } while (result == YAFFS_OK && n_bytes > 0);
168 yaffs_release_temp_buffer(dev, buffer);
169
170
171 if (result == YAFFS_OK)
172 bi->has_summary = 1;
173
174
175 return result;
176 }
177
yaffs_summary_read(struct yaffs_dev * dev,struct yaffs_summary_tags * st,int blk)178 int yaffs_summary_read(struct yaffs_dev *dev,
179 struct yaffs_summary_tags *st,
180 int blk)
181 {
182 struct yaffs_ext_tags tags;
183 u8 *buffer;
184 u8 *sum_buffer = (u8 *)st;
185 int n_bytes;
186 int chunk_id;
187 int chunk_in_nand;
188 int chunk_in_block;
189 int result;
190 int this_tx;
191 struct yaffs_summary_header hdr;
192 struct yaffs_block_info *bi = yaffs_get_block_info(dev, blk);
193 int sum_bytes_per_chunk = dev->data_bytes_per_chunk - sizeof(hdr);
194 int sum_tags_bytes;
195
196 sum_tags_bytes = sizeof(struct yaffs_summary_tags) *
197 dev->chunks_per_summary;
198 buffer = yaffs_get_temp_buffer(dev);
199 n_bytes = sizeof(struct yaffs_summary_tags) * dev->chunks_per_summary;
200 chunk_in_block = dev->chunks_per_summary;
201 chunk_in_nand = blk * dev->param.chunks_per_block +
202 dev->chunks_per_summary;
203 chunk_id = 1;
204 do {
205 this_tx = n_bytes;
206 if (this_tx > sum_bytes_per_chunk)
207 this_tx = sum_bytes_per_chunk;
208 result = yaffs_rd_chunk_tags_nand(dev, chunk_in_nand,
209 buffer, &tags);
210
211 if (tags.chunk_id != chunk_id ||
212 tags.obj_id != YAFFS_OBJECTID_SUMMARY ||
213 tags.chunk_used == 0 ||
214 tags.ecc_result > YAFFS_ECC_RESULT_FIXED ||
215 tags.n_bytes != (this_tx + sizeof(hdr)))
216 result = YAFFS_FAIL;
217 if (result != YAFFS_OK)
218 break;
219
220 if (st == dev->sum_tags) {
221 /* If we're scanning then update the block info */
222 yaffs_set_chunk_bit(dev, blk, chunk_in_block);
223 bi->pages_in_use++;
224 }
225 memcpy(&hdr, buffer, sizeof(hdr));
226 memcpy(sum_buffer, buffer + sizeof(hdr), this_tx);
227 n_bytes -= this_tx;
228 sum_buffer += this_tx;
229 chunk_in_nand++;
230 chunk_in_block++;
231 chunk_id++;
232 } while (result == YAFFS_OK && n_bytes > 0);
233 yaffs_release_temp_buffer(dev, buffer);
234
235 if (result == YAFFS_OK) {
236 /* Verify header */
237 if (hdr.version != YAFFS_SUMMARY_VERSION ||
238 hdr.block != blk ||
239 hdr.seq != bi->seq_number ||
240 hdr.sum != yaffs_summary_sum(dev))
241 result = YAFFS_FAIL;
242 }
243
244 if (st == dev->sum_tags && result == YAFFS_OK)
245 bi->has_summary = 1;
246
247 return result;
248 }
249
yaffs_summary_add(struct yaffs_dev * dev,struct yaffs_ext_tags * tags,int chunk_in_nand)250 int yaffs_summary_add(struct yaffs_dev *dev,
251 struct yaffs_ext_tags *tags,
252 int chunk_in_nand)
253 {
254 struct yaffs_packed_tags2_tags_only tags_only;
255 struct yaffs_summary_tags *sum_tags;
256 int block_in_nand = chunk_in_nand / dev->param.chunks_per_block;
257 int chunk_in_block = chunk_in_nand % dev->param.chunks_per_block;
258
259 if (!dev->sum_tags)
260 return YAFFS_OK;
261
262 if (chunk_in_block >= 0 && chunk_in_block < dev->chunks_per_summary) {
263 yaffs_pack_tags2_tags_only(&tags_only, tags);
264 sum_tags = &dev->sum_tags[chunk_in_block];
265 sum_tags->chunk_id = tags_only.chunk_id;
266 sum_tags->n_bytes = tags_only.n_bytes;
267 sum_tags->obj_id = tags_only.obj_id;
268
269 if (chunk_in_block == dev->chunks_per_summary - 1) {
270 /* Time to write out the summary */
271 yaffs_summary_write(dev, block_in_nand);
272 yaffs_summary_clear(dev);
273 yaffs_skip_rest_of_block(dev);
274 }
275 }
276 return YAFFS_OK;
277 }
278
yaffs_summary_fetch(struct yaffs_dev * dev,struct yaffs_ext_tags * tags,int chunk_in_block)279 int yaffs_summary_fetch(struct yaffs_dev *dev,
280 struct yaffs_ext_tags *tags,
281 int chunk_in_block)
282 {
283 struct yaffs_packed_tags2_tags_only tags_only;
284 struct yaffs_summary_tags *sum_tags;
285 if (chunk_in_block >= 0 && chunk_in_block < dev->chunks_per_summary) {
286 sum_tags = &dev->sum_tags[chunk_in_block];
287 tags_only.chunk_id = sum_tags->chunk_id;
288 tags_only.n_bytes = sum_tags->n_bytes;
289 tags_only.obj_id = sum_tags->obj_id;
290 yaffs_unpack_tags2_tags_only(tags, &tags_only);
291 return YAFFS_OK;
292 }
293 return YAFFS_FAIL;
294 }
295
yaffs_summary_gc(struct yaffs_dev * dev,int blk)296 void yaffs_summary_gc(struct yaffs_dev *dev, int blk)
297 {
298 struct yaffs_block_info *bi = yaffs_get_block_info(dev, blk);
299 int i;
300
301 if (!bi->has_summary)
302 return;
303
304 for (i = dev->chunks_per_summary;
305 i < dev->param.chunks_per_block;
306 i++) {
307 if (yaffs_check_chunk_bit(dev, blk, i)) {
308 yaffs_clear_chunk_bit(dev, blk, i);
309 bi->pages_in_use--;
310 dev->n_free_chunks++;
311 }
312 }
313 }
314