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yaml --- r: 146390 b: refs/heads/master c: 6fd058f h: refs/heads/master v: v3
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Theodore Ts'o
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May 17, 2009
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,2 +1,2 @@ | ||
| --- | ||
| refs/heads/master: 2ac3b6e00acb46406c993d57921f86a594aafe08 | ||
| refs/heads/master: 6fd058f7791087648c683eb8572edf3be3c4c23c |
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,244 @@ | ||
| /* | ||
| * linux/fs/ext4/block_validity.c | ||
| * | ||
| * Copyright (C) 2009 | ||
| * Theodore Ts'o (tytso@mit.edu) | ||
| * | ||
| * Track which blocks in the filesystem are metadata blocks that | ||
| * should never be used as data blocks by files or directories. | ||
| */ | ||
|
|
||
| #include <linux/time.h> | ||
| #include <linux/fs.h> | ||
| #include <linux/namei.h> | ||
| #include <linux/quotaops.h> | ||
| #include <linux/buffer_head.h> | ||
| #include <linux/module.h> | ||
| #include <linux/swap.h> | ||
| #include <linux/pagemap.h> | ||
| #include <linux/version.h> | ||
| #include <linux/blkdev.h> | ||
| #include <linux/mutex.h> | ||
| #include "ext4.h" | ||
|
|
||
| struct ext4_system_zone { | ||
| struct rb_node node; | ||
| ext4_fsblk_t start_blk; | ||
| unsigned int count; | ||
| }; | ||
|
|
||
| static struct kmem_cache *ext4_system_zone_cachep; | ||
|
|
||
| int __init init_ext4_system_zone(void) | ||
| { | ||
| ext4_system_zone_cachep = KMEM_CACHE(ext4_system_zone, | ||
| SLAB_RECLAIM_ACCOUNT); | ||
| if (ext4_system_zone_cachep == NULL) | ||
| return -ENOMEM; | ||
| return 0; | ||
| } | ||
|
|
||
| void exit_ext4_system_zone(void) | ||
| { | ||
| kmem_cache_destroy(ext4_system_zone_cachep); | ||
| } | ||
|
|
||
| static inline int can_merge(struct ext4_system_zone *entry1, | ||
| struct ext4_system_zone *entry2) | ||
| { | ||
| if ((entry1->start_blk + entry1->count) == entry2->start_blk) | ||
| return 1; | ||
| return 0; | ||
| } | ||
|
|
||
| /* | ||
| * Mark a range of blocks as belonging to the "system zone" --- that | ||
| * is, filesystem metadata blocks which should never be used by | ||
| * inodes. | ||
| */ | ||
| static int add_system_zone(struct ext4_sb_info *sbi, | ||
| ext4_fsblk_t start_blk, | ||
| unsigned int count) | ||
| { | ||
| struct ext4_system_zone *new_entry = NULL, *entry; | ||
| struct rb_node **n = &sbi->system_blks.rb_node, *node; | ||
| struct rb_node *parent = NULL, *new_node = NULL; | ||
|
|
||
| while (*n) { | ||
| parent = *n; | ||
| entry = rb_entry(parent, struct ext4_system_zone, node); | ||
| if (start_blk < entry->start_blk) | ||
| n = &(*n)->rb_left; | ||
| else if (start_blk >= (entry->start_blk + entry->count)) | ||
| n = &(*n)->rb_right; | ||
| else { | ||
| if (start_blk + count > (entry->start_blk + | ||
| entry->count)) | ||
| entry->count = (start_blk + count - | ||
| entry->start_blk); | ||
| new_node = *n; | ||
| new_entry = rb_entry(new_node, struct ext4_system_zone, | ||
| node); | ||
| break; | ||
| } | ||
| } | ||
|
|
||
| if (!new_entry) { | ||
| new_entry = kmem_cache_alloc(ext4_system_zone_cachep, | ||
| GFP_KERNEL); | ||
| if (!new_entry) | ||
| return -ENOMEM; | ||
| new_entry->start_blk = start_blk; | ||
| new_entry->count = count; | ||
| new_node = &new_entry->node; | ||
|
|
||
| rb_link_node(new_node, parent, n); | ||
| rb_insert_color(new_node, &sbi->system_blks); | ||
| } | ||
|
|
||
| /* Can we merge to the left? */ | ||
| node = rb_prev(new_node); | ||
| if (node) { | ||
| entry = rb_entry(node, struct ext4_system_zone, node); | ||
| if (can_merge(entry, new_entry)) { | ||
| new_entry->start_blk = entry->start_blk; | ||
| new_entry->count += entry->count; | ||
| rb_erase(node, &sbi->system_blks); | ||
| kmem_cache_free(ext4_system_zone_cachep, entry); | ||
| } | ||
| } | ||
|
|
||
| /* Can we merge to the right? */ | ||
| node = rb_next(new_node); | ||
| if (node) { | ||
| entry = rb_entry(node, struct ext4_system_zone, node); | ||
| if (can_merge(new_entry, entry)) { | ||
| new_entry->count += entry->count; | ||
| rb_erase(node, &sbi->system_blks); | ||
| kmem_cache_free(ext4_system_zone_cachep, entry); | ||
| } | ||
| } | ||
| return 0; | ||
| } | ||
|
|
||
| static void debug_print_tree(struct ext4_sb_info *sbi) | ||
| { | ||
| struct rb_node *node; | ||
| struct ext4_system_zone *entry; | ||
| int first = 1; | ||
|
|
||
| printk(KERN_INFO "System zones: "); | ||
| node = rb_first(&sbi->system_blks); | ||
| while (node) { | ||
| entry = rb_entry(node, struct ext4_system_zone, node); | ||
| printk("%s%llu-%llu", first ? "" : ", ", | ||
| entry->start_blk, entry->start_blk + entry->count - 1); | ||
| first = 0; | ||
| node = rb_next(node); | ||
| } | ||
| printk("\n"); | ||
| } | ||
|
|
||
| int ext4_setup_system_zone(struct super_block *sb) | ||
| { | ||
| ext4_group_t ngroups = ext4_get_groups_count(sb); | ||
| struct ext4_sb_info *sbi = EXT4_SB(sb); | ||
| struct ext4_group_desc *gdp; | ||
| ext4_group_t i; | ||
| int flex_size = ext4_flex_bg_size(sbi); | ||
| int ret; | ||
|
|
||
| if (!test_opt(sb, BLOCK_VALIDITY)) { | ||
| if (EXT4_SB(sb)->system_blks.rb_node) | ||
| ext4_release_system_zone(sb); | ||
| return 0; | ||
| } | ||
| if (EXT4_SB(sb)->system_blks.rb_node) | ||
| return 0; | ||
|
|
||
| for (i=0; i < ngroups; i++) { | ||
| if (ext4_bg_has_super(sb, i) && | ||
| ((i < 5) || ((i % flex_size) == 0))) | ||
| add_system_zone(sbi, ext4_group_first_block_no(sb, i), | ||
| sbi->s_gdb_count + 1); | ||
| gdp = ext4_get_group_desc(sb, i, NULL); | ||
| ret = add_system_zone(sbi, ext4_block_bitmap(sb, gdp), 1); | ||
| if (ret) | ||
| return ret; | ||
| ret = add_system_zone(sbi, ext4_inode_bitmap(sb, gdp), 1); | ||
| if (ret) | ||
| return ret; | ||
| ret = add_system_zone(sbi, ext4_inode_table(sb, gdp), | ||
| sbi->s_itb_per_group); | ||
| if (ret) | ||
| return ret; | ||
| } | ||
|
|
||
| if (test_opt(sb, DEBUG)) | ||
| debug_print_tree(EXT4_SB(sb)); | ||
| return 0; | ||
| } | ||
|
|
||
| /* Called when the filesystem is unmounted */ | ||
| void ext4_release_system_zone(struct super_block *sb) | ||
| { | ||
| struct rb_node *n = EXT4_SB(sb)->system_blks.rb_node; | ||
| struct rb_node *parent; | ||
| struct ext4_system_zone *entry; | ||
|
|
||
| while (n) { | ||
| /* Do the node's children first */ | ||
| if (n->rb_left) { | ||
| n = n->rb_left; | ||
| continue; | ||
| } | ||
| if (n->rb_right) { | ||
| n = n->rb_right; | ||
| continue; | ||
| } | ||
| /* | ||
| * The node has no children; free it, and then zero | ||
| * out parent's link to it. Finally go to the | ||
| * beginning of the loop and try to free the parent | ||
| * node. | ||
| */ | ||
| parent = rb_parent(n); | ||
| entry = rb_entry(n, struct ext4_system_zone, node); | ||
| kmem_cache_free(ext4_system_zone_cachep, entry); | ||
| if (!parent) | ||
| EXT4_SB(sb)->system_blks.rb_node = NULL; | ||
| else if (parent->rb_left == n) | ||
| parent->rb_left = NULL; | ||
| else if (parent->rb_right == n) | ||
| parent->rb_right = NULL; | ||
| n = parent; | ||
| } | ||
| EXT4_SB(sb)->system_blks.rb_node = NULL; | ||
| } | ||
|
|
||
| /* | ||
| * Returns 1 if the passed-in block region (start_blk, | ||
| * start_blk+count) is valid; 0 if some part of the block region | ||
| * overlaps with filesystem metadata blocks. | ||
| */ | ||
| int ext4_data_block_valid(struct ext4_sb_info *sbi, ext4_fsblk_t start_blk, | ||
| unsigned int count) | ||
| { | ||
| struct ext4_system_zone *entry; | ||
| struct rb_node *n = sbi->system_blks.rb_node; | ||
|
|
||
| if ((start_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) || | ||
| (start_blk + count > ext4_blocks_count(sbi->s_es))) | ||
| return 0; | ||
| while (n) { | ||
| entry = rb_entry(n, struct ext4_system_zone, node); | ||
| if (start_blk + count - 1 < entry->start_blk) | ||
| n = n->rb_left; | ||
| else if (start_blk >= (entry->start_blk + entry->count)) | ||
| n = n->rb_right; | ||
| else | ||
| return 0; | ||
| } | ||
| return 1; | ||
| } | ||
|
|
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