HAMMER UTILITY - Fix seg-fault on corrupt blockmap during recovery
[dragonfly.git] / sbin / hammer / blockmap.c
CommitLineData
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1/*
2 * Copyright (c) 2008 The DragonFly Project. All rights reserved.
3 *
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
16 * distribution.
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
68e079b8 34 * $DragonFly: src/sbin/hammer/blockmap.c,v 1.2 2008/06/17 04:03:38 dillon Exp $
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35 */
36
37#include "hammer.h"
38
39hammer_off_t
68e079b8 40blockmap_lookup(hammer_off_t zone_offset,
f03c9cf4 41 struct hammer_blockmap_layer1 *save_layer1,
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42 struct hammer_blockmap_layer2 *save_layer2,
43 int *errorp)
f03c9cf4 44{
b9107f58 45 struct volume_info *root_volume = NULL;
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46 hammer_blockmap_t blockmap;
47 hammer_blockmap_t freemap;
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48 struct hammer_blockmap_layer1 *layer1;
49 struct hammer_blockmap_layer2 *layer2;
50 struct buffer_info *buffer = NULL;
51 hammer_off_t layer1_offset;
52 hammer_off_t layer2_offset;
53 hammer_off_t result_offset;
54 int zone;
68e079b8 55 int i;
b9107f58 56 int error = 0;
f03c9cf4 57
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58 if (save_layer1)
59 *save_layer1 = NULL;
60 if (save_layer2)
61 *save_layer2 = NULL;
62
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63 zone = HAMMER_ZONE_DECODE(zone_offset);
64
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65 if (AssertOnFailure) {
66 assert(zone > HAMMER_ZONE_RAW_VOLUME_INDEX);
67 assert(zone < HAMMER_MAX_ZONES);
68 assert(RootVolNo >= 0);
69 } else {
70 if (zone <= HAMMER_ZONE_RAW_VOLUME_INDEX)
71 error = EDOM;
72 if (zone >= HAMMER_MAX_ZONES)
73 error = EDOM;
74 if (RootVolNo < 0)
75 error = EDOM;
76 if (error) {
77 result_offset = HAMMER_OFF_BAD;
78 goto done;
79 }
80 }
81
f03c9cf4 82 root_volume = get_volume(RootVolNo);
68e079b8 83 blockmap = &root_volume->ondisk->vol0_blockmap[zone];
f03c9cf4 84
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85 if (zone == HAMMER_ZONE_RAW_BUFFER_INDEX) {
86 result_offset = zone_offset;
87 } else if (zone == HAMMER_ZONE_UNDO_INDEX) {
88 i = (zone_offset & HAMMER_OFF_SHORT_MASK) /
89 HAMMER_LARGEBLOCK_SIZE;
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90 if (AssertOnFailure) {
91 assert(zone_offset < blockmap->alloc_offset);
92 } else {
93 if (zone_offset >= blockmap->alloc_offset) {
94 error = EDOM;
95 result_offset = HAMMER_OFF_BAD;
96 goto done;
97 }
98 }
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99 result_offset = root_volume->ondisk->vol0_undo_array[i] +
100 (zone_offset & HAMMER_LARGEBLOCK_MASK64);
101 } else {
102 result_offset = (zone_offset & ~HAMMER_OFF_ZONE_MASK) |
103 HAMMER_ZONE_RAW_BUFFER;
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104 }
105
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106 /*
107 * The blockmap should match the requested zone (else the volume
108 * header is mashed).
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109 *
110 * Note that a valid offset can still be returned if AssertOnFailure
111 * is zero.
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112 */
113 if (AssertOnFailure) {
114 assert(HAMMER_ZONE_DECODE(blockmap->alloc_offset) == zone);
115 } else {
116 if (HAMMER_ZONE_DECODE(blockmap->alloc_offset) != zone) {
117 error = EDOM;
118 goto done;
119 }
120 }
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121
122 /*
123 * Validate that the big-block is assigned to the zone. Also
124 * assign save_layer{1,2}.
125 */
126
127 freemap = &root_volume->ondisk->vol0_blockmap[HAMMER_ZONE_FREEMAP_INDEX];
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128 /*
129 * Dive layer 1.
130 */
68e079b8 131 layer1_offset = freemap->phys_offset +
6aec797f 132 HAMMER_BLOCKMAP_LAYER1_OFFSET(result_offset);
f03c9cf4 133 layer1 = get_buffer_data(layer1_offset, &buffer, 0);
b9107f58 134 if (AssertOnFailure) {
e0410f23 135 assert(layer1);
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136 assert(layer1->phys_offset != HAMMER_BLOCKMAP_UNAVAIL);
137 } else {
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138 if (layer1 == NULL) {
139 error = EDOM;
140 goto done;
141 }
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142 if (layer1->phys_offset == HAMMER_BLOCKMAP_UNAVAIL) {
143 error = EDOM;
144 goto done;
145 }
146 }
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147 if (save_layer1)
148 *save_layer1 = *layer1;
149
150 /*
151 * Dive layer 2, each entry represents a large-block.
152 */
153 layer2_offset = layer1->phys_offset +
6aec797f 154 HAMMER_BLOCKMAP_LAYER2_OFFSET(result_offset);
f03c9cf4 155 layer2 = get_buffer_data(layer2_offset, &buffer, 0);
f03c9cf4 156
b9107f58 157 if (AssertOnFailure) {
e0410f23 158 assert(layer2);
6ed4c886 159 assert(layer2->zone == zone);
b9107f58 160 } else {
e0410f23 161 if (layer2 == NULL) {
b9107f58 162 error = EDOM;
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163 goto done;
164 }
165 if (layer2->zone != zone) {
166 error = EDOM;
167 goto done;
168 }
6ed4c886 169 }
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170 if (save_layer2)
171 *save_layer2 = *layer2;
f03c9cf4 172
b9107f58 173done:
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174 if (buffer)
175 rel_buffer(buffer);
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176 if (root_volume)
177 rel_volume(root_volume);
178
179 if (errorp)
180 *errorp = error;
181
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182 return(result_offset);
183}
184