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 #include "yaffs_packedtags2.h"
15 #include "yportenv.h"
16 #include "yaffs_trace.h"
17
18 /* This code packs a set of extended tags into a binary structure for
19 * NAND storage
20 */
21
22 /* Some of the information is "extra" struff which can be packed in to
23 * speed scanning
24 * This is defined by having the EXTRA_HEADER_INFO_FLAG set.
25 */
26
27 /* Extra flags applied to chunk_id */
28
29 #define EXTRA_HEADER_INFO_FLAG 0x80000000
30 #define EXTRA_SHRINK_FLAG 0x40000000
31 #define EXTRA_SHADOWS_FLAG 0x20000000
32 #define EXTRA_SPARE_FLAGS 0x10000000
33
34 #define ALL_EXTRA_FLAGS 0xf0000000
35
36 /* Also, the top 4 bits of the object Id are set to the object type. */
37 #define EXTRA_OBJECT_TYPE_SHIFT (28)
38 #define EXTRA_OBJECT_TYPE_MASK ((0x0f) << EXTRA_OBJECT_TYPE_SHIFT)
39
yaffs_dump_packed_tags2_tags_only(const struct yaffs_packed_tags2_tags_only * ptt)40 static void yaffs_dump_packed_tags2_tags_only(
41 const struct yaffs_packed_tags2_tags_only *ptt)
42 {
43 yaffs_trace(YAFFS_TRACE_MTD,
44 "packed tags obj %d chunk %d byte %d seq %d",
45 ptt->obj_id, ptt->chunk_id, ptt->n_bytes, ptt->seq_number);
46 }
47
yaffs_dump_packed_tags2(const struct yaffs_packed_tags2 * pt)48 static void yaffs_dump_packed_tags2(const struct yaffs_packed_tags2 *pt)
49 {
50 yaffs_dump_packed_tags2_tags_only(&pt->t);
51 }
52
yaffs_dump_tags2(const struct yaffs_ext_tags * t)53 static void yaffs_dump_tags2(const struct yaffs_ext_tags *t)
54 {
55 yaffs_trace(YAFFS_TRACE_MTD,
56 "ext.tags eccres %d blkbad %d chused %d obj %d chunk%d byte %d del %d ser %d seq %d",
57 t->ecc_result, t->block_bad, t->chunk_used, t->obj_id,
58 t->chunk_id, t->n_bytes, t->is_deleted, t->serial_number,
59 t->seq_number);
60
61 }
62
yaffs_check_tags_extra_packable(const struct yaffs_ext_tags * t)63 static int yaffs_check_tags_extra_packable(const struct yaffs_ext_tags *t)
64 {
65 if (t->chunk_id != 0 || !t->extra_available)
66 return 0;
67
68 /* Check if the file size is too long to store */
69 if (t->extra_obj_type == YAFFS_OBJECT_TYPE_FILE &&
70 (t->extra_file_size >> 31) != 0)
71 return 0;
72 return 1;
73 }
74
yaffs_pack_tags2_tags_only(struct yaffs_packed_tags2_tags_only * ptt,const struct yaffs_ext_tags * t)75 void yaffs_pack_tags2_tags_only(struct yaffs_packed_tags2_tags_only *ptt,
76 const struct yaffs_ext_tags *t)
77 {
78 ptt->chunk_id = t->chunk_id;
79 ptt->seq_number = t->seq_number;
80 ptt->n_bytes = t->n_bytes;
81 ptt->obj_id = t->obj_id;
82
83 /* Only store extra tags for object headers.
84 * If it is a file then only store if the file size is short\
85 * enough to fit.
86 */
87 if (yaffs_check_tags_extra_packable(t)) {
88 /* Store the extra header info instead */
89 /* We save the parent object in the chunk_id */
90 ptt->chunk_id = EXTRA_HEADER_INFO_FLAG | t->extra_parent_id;
91 if (t->extra_is_shrink)
92 ptt->chunk_id |= EXTRA_SHRINK_FLAG;
93 if (t->extra_shadows)
94 ptt->chunk_id |= EXTRA_SHADOWS_FLAG;
95
96 ptt->obj_id &= ~EXTRA_OBJECT_TYPE_MASK;
97 ptt->obj_id |= (t->extra_obj_type << EXTRA_OBJECT_TYPE_SHIFT);
98
99 if (t->extra_obj_type == YAFFS_OBJECT_TYPE_HARDLINK)
100 ptt->n_bytes = t->extra_equiv_id;
101 else if (t->extra_obj_type == YAFFS_OBJECT_TYPE_FILE)
102 ptt->n_bytes = (unsigned) t->extra_file_size;
103 else
104 ptt->n_bytes = 0;
105 }
106
107 yaffs_dump_packed_tags2_tags_only(ptt);
108 yaffs_dump_tags2(t);
109 }
110
yaffs_pack_tags2(struct yaffs_packed_tags2 * pt,const struct yaffs_ext_tags * t,int tags_ecc)111 void yaffs_pack_tags2(struct yaffs_packed_tags2 *pt,
112 const struct yaffs_ext_tags *t, int tags_ecc)
113 {
114 yaffs_pack_tags2_tags_only(&pt->t, t);
115
116 if (tags_ecc)
117 yaffs_ecc_calc_other((unsigned char *)&pt->t,
118 sizeof(struct yaffs_packed_tags2_tags_only),
119 &pt->ecc);
120 }
121
yaffs_unpack_tags2_tags_only(struct yaffs_ext_tags * t,struct yaffs_packed_tags2_tags_only * ptt)122 void yaffs_unpack_tags2_tags_only(struct yaffs_ext_tags *t,
123 struct yaffs_packed_tags2_tags_only *ptt)
124 {
125 memset(t, 0, sizeof(struct yaffs_ext_tags));
126
127 if (ptt->seq_number == 0xffffffff)
128 return;
129
130 t->block_bad = 0;
131 t->chunk_used = 1;
132 t->obj_id = ptt->obj_id;
133 t->chunk_id = ptt->chunk_id;
134 t->n_bytes = ptt->n_bytes;
135 t->is_deleted = 0;
136 t->serial_number = 0;
137 t->seq_number = ptt->seq_number;
138
139 /* Do extra header info stuff */
140 if (ptt->chunk_id & EXTRA_HEADER_INFO_FLAG) {
141 t->chunk_id = 0;
142 t->n_bytes = 0;
143
144 t->extra_available = 1;
145 t->extra_parent_id = ptt->chunk_id & (~(ALL_EXTRA_FLAGS));
146 t->extra_is_shrink = ptt->chunk_id & EXTRA_SHRINK_FLAG ? 1 : 0;
147 t->extra_shadows = ptt->chunk_id & EXTRA_SHADOWS_FLAG ? 1 : 0;
148 t->extra_obj_type = ptt->obj_id >> EXTRA_OBJECT_TYPE_SHIFT;
149 t->obj_id &= ~EXTRA_OBJECT_TYPE_MASK;
150
151 if (t->extra_obj_type == YAFFS_OBJECT_TYPE_HARDLINK)
152 t->extra_equiv_id = ptt->n_bytes;
153 else
154 t->extra_file_size = ptt->n_bytes;
155 }
156 yaffs_dump_packed_tags2_tags_only(ptt);
157 yaffs_dump_tags2(t);
158 }
159
yaffs_unpack_tags2(struct yaffs_ext_tags * t,struct yaffs_packed_tags2 * pt,int tags_ecc)160 void yaffs_unpack_tags2(struct yaffs_ext_tags *t, struct yaffs_packed_tags2 *pt,
161 int tags_ecc)
162 {
163 enum yaffs_ecc_result ecc_result = YAFFS_ECC_RESULT_NO_ERROR;
164
165 if (pt->t.seq_number != 0xffffffff && tags_ecc) {
166 /* Chunk is in use and we need to do ECC */
167
168 struct yaffs_ecc_other ecc;
169 int result;
170 yaffs_ecc_calc_other((unsigned char *)&pt->t,
171 sizeof(struct yaffs_packed_tags2_tags_only),
172 &ecc);
173 result =
174 yaffs_ecc_correct_other((unsigned char *)&pt->t,
175 sizeof(struct yaffs_packed_tags2_tags_only),
176 &pt->ecc, &ecc);
177 switch (result) {
178 case 0:
179 ecc_result = YAFFS_ECC_RESULT_NO_ERROR;
180 break;
181 case 1:
182 ecc_result = YAFFS_ECC_RESULT_FIXED;
183 break;
184 case -1:
185 ecc_result = YAFFS_ECC_RESULT_UNFIXED;
186 break;
187 default:
188 ecc_result = YAFFS_ECC_RESULT_UNKNOWN;
189 }
190 }
191 yaffs_unpack_tags2_tags_only(t, &pt->t);
192
193 t->ecc_result = ecc_result;
194
195 yaffs_dump_packed_tags2(pt);
196 yaffs_dump_tags2(t);
197 }
198