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1/*
2 * linux/fs/ext4/block_validity.c
3 *
4 * Copyright (C) 2009
5 * Theodore Ts'o (tytso@mit.edu)
6 *
7 * Track which blocks in the filesystem are metadata blocks that
8 * should never be used as data blocks by files or directories.
9 */
10
11#include <linux/time.h>
12#include <linux/fs.h>
13#include <linux/namei.h>
14#include <linux/quotaops.h>
15#include <linux/buffer_head.h>
16#include <linux/swap.h>
17#include <linux/pagemap.h>
18#include <linux/blkdev.h>
19#include <linux/mutex.h>
20#include <linux/slab.h>
21#include "ext4.h"
22
23struct ext4_system_zone {
24 struct rb_node node;
25 ext4_fsblk_t start_blk;
26 unsigned int count;
27};
28
29static struct kmem_cache *ext4_system_zone_cachep;
30
31int __init ext4_init_system_zone(void)
32{
33 ext4_system_zone_cachep = KMEM_CACHE(ext4_system_zone, 0);
34 if (ext4_system_zone_cachep == NULL)
35 return -ENOMEM;
36 return 0;
37}
38
39void ext4_exit_system_zone(void)
40{
41 kmem_cache_destroy(ext4_system_zone_cachep);
42}
43
44static inline int can_merge(struct ext4_system_zone *entry1,
45 struct ext4_system_zone *entry2)
46{
47 if ((entry1->start_blk + entry1->count) == entry2->start_blk)
48 return 1;
49 return 0;
50}
51
52/*
53 * Mark a range of blocks as belonging to the "system zone" --- that
54 * is, filesystem metadata blocks which should never be used by
55 * inodes.
56 */
57static int add_system_zone(struct ext4_sb_info *sbi,
58 ext4_fsblk_t start_blk,
59 unsigned int count)
60{
61 struct ext4_system_zone *new_entry = NULL, *entry;
62 struct rb_node **n = &sbi->system_blks.rb_node, *node;
63 struct rb_node *parent = NULL, *new_node = NULL;
64
65 while (*n) {
66 parent = *n;
67 entry = rb_entry(parent, struct ext4_system_zone, node);
68 if (start_blk < entry->start_blk)
69 n = &(*n)->rb_left;
70 else if (start_blk >= (entry->start_blk + entry->count))
71 n = &(*n)->rb_right;
72 else {
73 if (start_blk + count > (entry->start_blk +
74 entry->count))
75 entry->count = (start_blk + count -
76 entry->start_blk);
77 new_node = *n;
78 new_entry = rb_entry(new_node, struct ext4_system_zone,
79 node);
80 break;
81 }
82 }
83
84 if (!new_entry) {
85 new_entry = kmem_cache_alloc(ext4_system_zone_cachep,
86 GFP_KERNEL);
87 if (!new_entry)
88 return -ENOMEM;
89 new_entry->start_blk = start_blk;
90 new_entry->count = count;
91 new_node = &new_entry->node;
92
93 rb_link_node(new_node, parent, n);
94 rb_insert_color(new_node, &sbi->system_blks);
95 }
96
97 /* Can we merge to the left? */
98 node = rb_prev(new_node);
99 if (node) {
100 entry = rb_entry(node, struct ext4_system_zone, node);
101 if (can_merge(entry, new_entry)) {
102 new_entry->start_blk = entry->start_blk;
103 new_entry->count += entry->count;
104 rb_erase(node, &sbi->system_blks);
105 kmem_cache_free(ext4_system_zone_cachep, entry);
106 }
107 }
108
109 /* Can we merge to the right? */
110 node = rb_next(new_node);
111 if (node) {
112 entry = rb_entry(node, struct ext4_system_zone, node);
113 if (can_merge(new_entry, entry)) {
114 new_entry->count += entry->count;
115 rb_erase(node, &sbi->system_blks);
116 kmem_cache_free(ext4_system_zone_cachep, entry);
117 }
118 }
119 return 0;
120}
121
122static void debug_print_tree(struct ext4_sb_info *sbi)
123{
124 struct rb_node *node;
125 struct ext4_system_zone *entry;
126 int first = 1;
127
128 printk(KERN_INFO "System zones: ");
129 node = rb_first(&sbi->system_blks);
130 while (node) {
131 entry = rb_entry(node, struct ext4_system_zone, node);
132 printk("%s%llu-%llu", first ? "" : ", ",
133 entry->start_blk, entry->start_blk + entry->count - 1);
134 first = 0;
135 node = rb_next(node);
136 }
137 printk("\n");
138}
139
140int ext4_setup_system_zone(struct super_block *sb)
141{
142 ext4_group_t ngroups = ext4_get_groups_count(sb);
143 struct ext4_sb_info *sbi = EXT4_SB(sb);
144 struct ext4_group_desc *gdp;
145 ext4_group_t i;
146 int flex_size = ext4_flex_bg_size(sbi);
147 int ret;
148
149 if (!test_opt(sb, BLOCK_VALIDITY)) {
150 if (EXT4_SB(sb)->system_blks.rb_node)
151 ext4_release_system_zone(sb);
152 return 0;
153 }
154 if (EXT4_SB(sb)->system_blks.rb_node)
155 return 0;
156
157 for (i=0; i < ngroups; i++) {
158 if (ext4_bg_has_super(sb, i) &&
159 ((i < 5) || ((i % flex_size) == 0)))
160 add_system_zone(sbi, ext4_group_first_block_no(sb, i),
161 ext4_bg_num_gdb(sb, i) + 1);
162 gdp = ext4_get_group_desc(sb, i, NULL);
163 ret = add_system_zone(sbi, ext4_block_bitmap(sb, gdp), 1);
164 if (ret)
165 return ret;
166 ret = add_system_zone(sbi, ext4_inode_bitmap(sb, gdp), 1);
167 if (ret)
168 return ret;
169 ret = add_system_zone(sbi, ext4_inode_table(sb, gdp),
170 sbi->s_itb_per_group);
171 if (ret)
172 return ret;
173 }
174
175 if (test_opt(sb, DEBUG))
176 debug_print_tree(EXT4_SB(sb));
177 return 0;
178}
179
180/* Called when the filesystem is unmounted */
181void ext4_release_system_zone(struct super_block *sb)
182{
183 struct rb_node *n = EXT4_SB(sb)->system_blks.rb_node;
184 struct rb_node *parent;
185 struct ext4_system_zone *entry;
186
187 while (n) {
188 /* Do the node's children first */
189 if (n->rb_left) {
190 n = n->rb_left;
191 continue;
192 }
193 if (n->rb_right) {
194 n = n->rb_right;
195 continue;
196 }
197 /*
198 * The node has no children; free it, and then zero
199 * out parent's link to it. Finally go to the
200 * beginning of the loop and try to free the parent
201 * node.
202 */
203 parent = rb_parent(n);
204 entry = rb_entry(n, struct ext4_system_zone, node);
205 kmem_cache_free(ext4_system_zone_cachep, entry);
206 if (!parent)
207 EXT4_SB(sb)->system_blks = RB_ROOT;
208 else if (parent->rb_left == n)
209 parent->rb_left = NULL;
210 else if (parent->rb_right == n)
211 parent->rb_right = NULL;
212 n = parent;
213 }
214 EXT4_SB(sb)->system_blks = RB_ROOT;
215}
216
217/*
218 * Returns 1 if the passed-in block region (start_blk,
219 * start_blk+count) is valid; 0 if some part of the block region
220 * overlaps with filesystem metadata blocks.
221 */
222int ext4_data_block_valid(struct ext4_sb_info *sbi, ext4_fsblk_t start_blk,
223 unsigned int count)
224{
225 struct ext4_system_zone *entry;
226 struct rb_node *n = sbi->system_blks.rb_node;
227
228 if ((start_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
229 (start_blk + count < start_blk) ||
230 (start_blk + count > ext4_blocks_count(sbi->s_es))) {
231 sbi->s_es->s_last_error_block = cpu_to_le64(start_blk);
232 return 0;
233 }
234 while (n) {
235 entry = rb_entry(n, struct ext4_system_zone, node);
236 if (start_blk + count - 1 < entry->start_blk)
237 n = n->rb_left;
238 else if (start_blk >= (entry->start_blk + entry->count))
239 n = n->rb_right;
240 else {
241 sbi->s_es->s_last_error_block = cpu_to_le64(start_blk);
242 return 0;
243 }
244 }
245 return 1;
246}
247
248int ext4_check_blockref(const char *function, unsigned int line,
249 struct inode *inode, __le32 *p, unsigned int max)
250{
251 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
252 __le32 *bref = p;
253 unsigned int blk;
254
255 while (bref < p+max) {
256 blk = le32_to_cpu(*bref++);
257 if (blk &&
258 unlikely(!ext4_data_block_valid(EXT4_SB(inode->i_sb),
259 blk, 1))) {
260 es->s_last_error_block = cpu_to_le64(blk);
261 ext4_error_inode(inode, function, line, blk,
262 "invalid block");
263 return -EIO;
264 }
265 }
266 return 0;
267}
268
1/*
2 * linux/fs/ext4/block_validity.c
3 *
4 * Copyright (C) 2009
5 * Theodore Ts'o (tytso@mit.edu)
6 *
7 * Track which blocks in the filesystem are metadata blocks that
8 * should never be used as data blocks by files or directories.
9 */
10
11#include <linux/time.h>
12#include <linux/fs.h>
13#include <linux/namei.h>
14#include <linux/quotaops.h>
15#include <linux/buffer_head.h>
16#include <linux/swap.h>
17#include <linux/pagemap.h>
18#include <linux/blkdev.h>
19#include <linux/slab.h>
20#include "ext4.h"
21
22struct ext4_system_zone {
23 struct rb_node node;
24 ext4_fsblk_t start_blk;
25 unsigned int count;
26};
27
28static struct kmem_cache *ext4_system_zone_cachep;
29
30int __init ext4_init_system_zone(void)
31{
32 ext4_system_zone_cachep = KMEM_CACHE(ext4_system_zone, 0);
33 if (ext4_system_zone_cachep == NULL)
34 return -ENOMEM;
35 return 0;
36}
37
38void ext4_exit_system_zone(void)
39{
40 kmem_cache_destroy(ext4_system_zone_cachep);
41}
42
43static inline int can_merge(struct ext4_system_zone *entry1,
44 struct ext4_system_zone *entry2)
45{
46 if ((entry1->start_blk + entry1->count) == entry2->start_blk)
47 return 1;
48 return 0;
49}
50
51/*
52 * Mark a range of blocks as belonging to the "system zone" --- that
53 * is, filesystem metadata blocks which should never be used by
54 * inodes.
55 */
56static int add_system_zone(struct ext4_sb_info *sbi,
57 ext4_fsblk_t start_blk,
58 unsigned int count)
59{
60 struct ext4_system_zone *new_entry = NULL, *entry;
61 struct rb_node **n = &sbi->system_blks.rb_node, *node;
62 struct rb_node *parent = NULL, *new_node = NULL;
63
64 while (*n) {
65 parent = *n;
66 entry = rb_entry(parent, struct ext4_system_zone, node);
67 if (start_blk < entry->start_blk)
68 n = &(*n)->rb_left;
69 else if (start_blk >= (entry->start_blk + entry->count))
70 n = &(*n)->rb_right;
71 else {
72 if (start_blk + count > (entry->start_blk +
73 entry->count))
74 entry->count = (start_blk + count -
75 entry->start_blk);
76 new_node = *n;
77 new_entry = rb_entry(new_node, struct ext4_system_zone,
78 node);
79 break;
80 }
81 }
82
83 if (!new_entry) {
84 new_entry = kmem_cache_alloc(ext4_system_zone_cachep,
85 GFP_KERNEL);
86 if (!new_entry)
87 return -ENOMEM;
88 new_entry->start_blk = start_blk;
89 new_entry->count = count;
90 new_node = &new_entry->node;
91
92 rb_link_node(new_node, parent, n);
93 rb_insert_color(new_node, &sbi->system_blks);
94 }
95
96 /* Can we merge to the left? */
97 node = rb_prev(new_node);
98 if (node) {
99 entry = rb_entry(node, struct ext4_system_zone, node);
100 if (can_merge(entry, new_entry)) {
101 new_entry->start_blk = entry->start_blk;
102 new_entry->count += entry->count;
103 rb_erase(node, &sbi->system_blks);
104 kmem_cache_free(ext4_system_zone_cachep, entry);
105 }
106 }
107
108 /* Can we merge to the right? */
109 node = rb_next(new_node);
110 if (node) {
111 entry = rb_entry(node, struct ext4_system_zone, node);
112 if (can_merge(new_entry, entry)) {
113 new_entry->count += entry->count;
114 rb_erase(node, &sbi->system_blks);
115 kmem_cache_free(ext4_system_zone_cachep, entry);
116 }
117 }
118 return 0;
119}
120
121static void debug_print_tree(struct ext4_sb_info *sbi)
122{
123 struct rb_node *node;
124 struct ext4_system_zone *entry;
125 int first = 1;
126
127 printk(KERN_INFO "System zones: ");
128 node = rb_first(&sbi->system_blks);
129 while (node) {
130 entry = rb_entry(node, struct ext4_system_zone, node);
131 printk("%s%llu-%llu", first ? "" : ", ",
132 entry->start_blk, entry->start_blk + entry->count - 1);
133 first = 0;
134 node = rb_next(node);
135 }
136 printk("\n");
137}
138
139int ext4_setup_system_zone(struct super_block *sb)
140{
141 ext4_group_t ngroups = ext4_get_groups_count(sb);
142 struct ext4_sb_info *sbi = EXT4_SB(sb);
143 struct ext4_group_desc *gdp;
144 ext4_group_t i;
145 int flex_size = ext4_flex_bg_size(sbi);
146 int ret;
147
148 if (!test_opt(sb, BLOCK_VALIDITY)) {
149 if (EXT4_SB(sb)->system_blks.rb_node)
150 ext4_release_system_zone(sb);
151 return 0;
152 }
153 if (EXT4_SB(sb)->system_blks.rb_node)
154 return 0;
155
156 for (i=0; i < ngroups; i++) {
157 if (ext4_bg_has_super(sb, i) &&
158 ((i < 5) || ((i % flex_size) == 0)))
159 add_system_zone(sbi, ext4_group_first_block_no(sb, i),
160 ext4_bg_num_gdb(sb, i) + 1);
161 gdp = ext4_get_group_desc(sb, i, NULL);
162 ret = add_system_zone(sbi, ext4_block_bitmap(sb, gdp), 1);
163 if (ret)
164 return ret;
165 ret = add_system_zone(sbi, ext4_inode_bitmap(sb, gdp), 1);
166 if (ret)
167 return ret;
168 ret = add_system_zone(sbi, ext4_inode_table(sb, gdp),
169 sbi->s_itb_per_group);
170 if (ret)
171 return ret;
172 }
173
174 if (test_opt(sb, DEBUG))
175 debug_print_tree(EXT4_SB(sb));
176 return 0;
177}
178
179/* Called when the filesystem is unmounted */
180void ext4_release_system_zone(struct super_block *sb)
181{
182 struct ext4_system_zone *entry, *n;
183
184 rbtree_postorder_for_each_entry_safe(entry, n,
185 &EXT4_SB(sb)->system_blks, node)
186 kmem_cache_free(ext4_system_zone_cachep, entry);
187
188 EXT4_SB(sb)->system_blks = RB_ROOT;
189}
190
191/*
192 * Returns 1 if the passed-in block region (start_blk,
193 * start_blk+count) is valid; 0 if some part of the block region
194 * overlaps with filesystem metadata blocks.
195 */
196int ext4_data_block_valid(struct ext4_sb_info *sbi, ext4_fsblk_t start_blk,
197 unsigned int count)
198{
199 struct ext4_system_zone *entry;
200 struct rb_node *n = sbi->system_blks.rb_node;
201
202 if ((start_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
203 (start_blk + count < start_blk) ||
204 (start_blk + count > ext4_blocks_count(sbi->s_es))) {
205 sbi->s_es->s_last_error_block = cpu_to_le64(start_blk);
206 return 0;
207 }
208 while (n) {
209 entry = rb_entry(n, struct ext4_system_zone, node);
210 if (start_blk + count - 1 < entry->start_blk)
211 n = n->rb_left;
212 else if (start_blk >= (entry->start_blk + entry->count))
213 n = n->rb_right;
214 else {
215 sbi->s_es->s_last_error_block = cpu_to_le64(start_blk);
216 return 0;
217 }
218 }
219 return 1;
220}
221
222int ext4_check_blockref(const char *function, unsigned int line,
223 struct inode *inode, __le32 *p, unsigned int max)
224{
225 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
226 __le32 *bref = p;
227 unsigned int blk;
228
229 while (bref < p+max) {
230 blk = le32_to_cpu(*bref++);
231 if (blk &&
232 unlikely(!ext4_data_block_valid(EXT4_SB(inode->i_sb),
233 blk, 1))) {
234 es->s_last_error_block = cpu_to_le64(blk);
235 ext4_error_inode(inode, function, line, blk,
236 "invalid block");
237 return -EFSCORRUPTED;
238 }
239 }
240 return 0;
241}
242