2 * linux/fs/ext4/block_validity.c
5 * Theodore Ts'o (tytso@mit.edu)
7 * Track which blocks in the filesystem are metadata blocks that
8 * should never be used as data blocks by files or directories.
11 #include <linux/time.h>
13 #include <linux/namei.h>
14 #include <linux/quotaops.h>
15 #include <linux/buffer_head.h>
16 #include <linux/module.h>
17 #include <linux/swap.h>
18 #include <linux/pagemap.h>
19 #include <linux/blkdev.h>
20 #include <linux/mutex.h>
21 #include <linux/slab.h>
24 struct ext4_system_zone {
26 ext4_fsblk_t start_blk;
30 static struct kmem_cache *ext4_system_zone_cachep;
32 int __init ext4_init_system_zone(void)
34 ext4_system_zone_cachep = KMEM_CACHE(ext4_system_zone, 0);
35 if (ext4_system_zone_cachep == NULL)
40 void ext4_exit_system_zone(void)
42 kmem_cache_destroy(ext4_system_zone_cachep);
45 static inline int can_merge(struct ext4_system_zone *entry1,
46 struct ext4_system_zone *entry2)
48 if ((entry1->start_blk + entry1->count) == entry2->start_blk)
54 * Mark a range of blocks as belonging to the "system zone" --- that
55 * is, filesystem metadata blocks which should never be used by
58 static int add_system_zone(struct ext4_sb_info *sbi,
59 ext4_fsblk_t start_blk,
62 struct ext4_system_zone *new_entry = NULL, *entry;
63 struct rb_node **n = &sbi->system_blks.rb_node, *node;
64 struct rb_node *parent = NULL, *new_node = NULL;
68 entry = rb_entry(parent, struct ext4_system_zone, node);
69 if (start_blk < entry->start_blk)
71 else if (start_blk >= (entry->start_blk + entry->count))
74 if (start_blk + count > (entry->start_blk +
76 entry->count = (start_blk + count -
79 new_entry = rb_entry(new_node, struct ext4_system_zone,
86 new_entry = kmem_cache_alloc(ext4_system_zone_cachep,
90 new_entry->start_blk = start_blk;
91 new_entry->count = count;
92 new_node = &new_entry->node;
94 rb_link_node(new_node, parent, n);
95 rb_insert_color(new_node, &sbi->system_blks);
98 /* Can we merge to the left? */
99 node = rb_prev(new_node);
101 entry = rb_entry(node, struct ext4_system_zone, node);
102 if (can_merge(entry, new_entry)) {
103 new_entry->start_blk = entry->start_blk;
104 new_entry->count += entry->count;
105 rb_erase(node, &sbi->system_blks);
106 kmem_cache_free(ext4_system_zone_cachep, entry);
110 /* Can we merge to the right? */
111 node = rb_next(new_node);
113 entry = rb_entry(node, struct ext4_system_zone, node);
114 if (can_merge(new_entry, entry)) {
115 new_entry->count += entry->count;
116 rb_erase(node, &sbi->system_blks);
117 kmem_cache_free(ext4_system_zone_cachep, entry);
123 static void debug_print_tree(struct ext4_sb_info *sbi)
125 struct rb_node *node;
126 struct ext4_system_zone *entry;
129 printk(KERN_INFO "System zones: ");
130 node = rb_first(&sbi->system_blks);
132 entry = rb_entry(node, struct ext4_system_zone, node);
133 printk("%s%llu-%llu", first ? "" : ", ",
134 entry->start_blk, entry->start_blk + entry->count - 1);
136 node = rb_next(node);
141 int ext4_setup_system_zone(struct super_block *sb)
143 ext4_group_t ngroups = ext4_get_groups_count(sb);
144 struct ext4_sb_info *sbi = EXT4_SB(sb);
145 struct ext4_group_desc *gdp;
147 int flex_size = ext4_flex_bg_size(sbi);
150 if (!test_opt(sb, BLOCK_VALIDITY)) {
151 if (EXT4_SB(sb)->system_blks.rb_node)
152 ext4_release_system_zone(sb);
155 if (EXT4_SB(sb)->system_blks.rb_node)
158 for (i=0; i < ngroups; i++) {
159 if (ext4_bg_has_super(sb, i) &&
160 ((i < 5) || ((i % flex_size) == 0)))
161 add_system_zone(sbi, ext4_group_first_block_no(sb, i),
162 ext4_bg_num_gdb(sb, i) + 1);
163 gdp = ext4_get_group_desc(sb, i, NULL);
164 ret = add_system_zone(sbi, ext4_block_bitmap(sb, gdp), 1);
167 ret = add_system_zone(sbi, ext4_inode_bitmap(sb, gdp), 1);
170 ret = add_system_zone(sbi, ext4_inode_table(sb, gdp),
171 sbi->s_itb_per_group);
176 if (test_opt(sb, DEBUG))
177 debug_print_tree(EXT4_SB(sb));
181 /* Called when the filesystem is unmounted */
182 void ext4_release_system_zone(struct super_block *sb)
184 struct rb_node *n = EXT4_SB(sb)->system_blks.rb_node;
185 struct rb_node *parent;
186 struct ext4_system_zone *entry;
189 /* Do the node's children first */
199 * The node has no children; free it, and then zero
200 * out parent's link to it. Finally go to the
201 * beginning of the loop and try to free the parent
204 parent = rb_parent(n);
205 entry = rb_entry(n, struct ext4_system_zone, node);
206 kmem_cache_free(ext4_system_zone_cachep, entry);
208 EXT4_SB(sb)->system_blks = RB_ROOT;
209 else if (parent->rb_left == n)
210 parent->rb_left = NULL;
211 else if (parent->rb_right == n)
212 parent->rb_right = NULL;
215 EXT4_SB(sb)->system_blks = RB_ROOT;
219 * Returns 1 if the passed-in block region (start_blk,
220 * start_blk+count) is valid; 0 if some part of the block region
221 * overlaps with filesystem metadata blocks.
223 int ext4_data_block_valid(struct ext4_sb_info *sbi, ext4_fsblk_t start_blk,
226 struct ext4_system_zone *entry;
227 struct rb_node *n = sbi->system_blks.rb_node;
229 if ((start_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
230 (start_blk + count < start_blk) ||
231 (start_blk + count > ext4_blocks_count(sbi->s_es))) {
232 sbi->s_es->s_last_error_block = cpu_to_le64(start_blk);
236 entry = rb_entry(n, struct ext4_system_zone, node);
237 if (start_blk + count - 1 < entry->start_blk)
239 else if (start_blk >= (entry->start_blk + entry->count))
242 sbi->s_es->s_last_error_block = cpu_to_le64(start_blk);
249 int ext4_check_blockref(const char *function, unsigned int line,
250 struct inode *inode, __le32 *p, unsigned int max)
252 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
256 while (bref < p+max) {
257 blk = le32_to_cpu(*bref++);
259 unlikely(!ext4_data_block_valid(EXT4_SB(inode->i_sb),
261 es->s_last_error_block = cpu_to_le64(blk);
262 ext4_error_inode(inode, function, line, blk,