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![Theodore Ts'o](/assets/img/avatar_default.png)
Also remove the SLAB_RECLAIM_ACCOUNT flag from the system zone kmem cache. This slab tends to be fairly static, so it shouldn't be marked as likely to have free pages that can be reclaimed. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
248 lines
6.2 KiB
C
248 lines
6.2 KiB
C
/*
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* linux/fs/ext4/block_validity.c
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*
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* Copyright (C) 2009
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* Theodore Ts'o (tytso@mit.edu)
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*
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* Track which blocks in the filesystem are metadata blocks that
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* should never be used as data blocks by files or directories.
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*/
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#include <linux/time.h>
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#include <linux/fs.h>
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#include <linux/namei.h>
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#include <linux/quotaops.h>
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#include <linux/buffer_head.h>
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#include <linux/module.h>
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#include <linux/swap.h>
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#include <linux/pagemap.h>
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#include <linux/blkdev.h>
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#include <linux/mutex.h>
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#include <linux/slab.h>
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#include "ext4.h"
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struct ext4_system_zone {
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struct rb_node node;
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ext4_fsblk_t start_blk;
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unsigned int count;
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};
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static struct kmem_cache *ext4_system_zone_cachep;
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int __init init_ext4_system_zone(void)
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{
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ext4_system_zone_cachep = KMEM_CACHE(ext4_system_zone, 0);
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if (ext4_system_zone_cachep == NULL)
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return -ENOMEM;
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return 0;
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}
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void exit_ext4_system_zone(void)
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{
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kmem_cache_destroy(ext4_system_zone_cachep);
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}
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static inline int can_merge(struct ext4_system_zone *entry1,
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struct ext4_system_zone *entry2)
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{
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if ((entry1->start_blk + entry1->count) == entry2->start_blk)
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return 1;
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return 0;
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}
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/*
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* Mark a range of blocks as belonging to the "system zone" --- that
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* is, filesystem metadata blocks which should never be used by
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* inodes.
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*/
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static int add_system_zone(struct ext4_sb_info *sbi,
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ext4_fsblk_t start_blk,
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unsigned int count)
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{
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struct ext4_system_zone *new_entry = NULL, *entry;
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struct rb_node **n = &sbi->system_blks.rb_node, *node;
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struct rb_node *parent = NULL, *new_node = NULL;
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while (*n) {
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parent = *n;
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entry = rb_entry(parent, struct ext4_system_zone, node);
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if (start_blk < entry->start_blk)
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n = &(*n)->rb_left;
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else if (start_blk >= (entry->start_blk + entry->count))
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n = &(*n)->rb_right;
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else {
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if (start_blk + count > (entry->start_blk +
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entry->count))
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entry->count = (start_blk + count -
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entry->start_blk);
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new_node = *n;
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new_entry = rb_entry(new_node, struct ext4_system_zone,
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node);
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break;
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}
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}
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if (!new_entry) {
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new_entry = kmem_cache_alloc(ext4_system_zone_cachep,
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GFP_KERNEL);
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if (!new_entry)
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return -ENOMEM;
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new_entry->start_blk = start_blk;
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new_entry->count = count;
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new_node = &new_entry->node;
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rb_link_node(new_node, parent, n);
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rb_insert_color(new_node, &sbi->system_blks);
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}
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/* Can we merge to the left? */
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node = rb_prev(new_node);
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if (node) {
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entry = rb_entry(node, struct ext4_system_zone, node);
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if (can_merge(entry, new_entry)) {
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new_entry->start_blk = entry->start_blk;
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new_entry->count += entry->count;
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rb_erase(node, &sbi->system_blks);
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kmem_cache_free(ext4_system_zone_cachep, entry);
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}
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}
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/* Can we merge to the right? */
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node = rb_next(new_node);
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if (node) {
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entry = rb_entry(node, struct ext4_system_zone, node);
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if (can_merge(new_entry, entry)) {
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new_entry->count += entry->count;
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rb_erase(node, &sbi->system_blks);
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kmem_cache_free(ext4_system_zone_cachep, entry);
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}
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}
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return 0;
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}
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static void debug_print_tree(struct ext4_sb_info *sbi)
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{
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struct rb_node *node;
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struct ext4_system_zone *entry;
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int first = 1;
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printk(KERN_INFO "System zones: ");
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node = rb_first(&sbi->system_blks);
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while (node) {
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entry = rb_entry(node, struct ext4_system_zone, node);
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printk("%s%llu-%llu", first ? "" : ", ",
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entry->start_blk, entry->start_blk + entry->count - 1);
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first = 0;
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node = rb_next(node);
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}
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printk("\n");
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}
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int ext4_setup_system_zone(struct super_block *sb)
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{
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ext4_group_t ngroups = ext4_get_groups_count(sb);
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struct ext4_sb_info *sbi = EXT4_SB(sb);
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struct ext4_group_desc *gdp;
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ext4_group_t i;
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int flex_size = ext4_flex_bg_size(sbi);
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int ret;
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if (!test_opt(sb, BLOCK_VALIDITY)) {
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if (EXT4_SB(sb)->system_blks.rb_node)
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ext4_release_system_zone(sb);
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return 0;
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}
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if (EXT4_SB(sb)->system_blks.rb_node)
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return 0;
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for (i=0; i < ngroups; i++) {
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if (ext4_bg_has_super(sb, i) &&
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((i < 5) || ((i % flex_size) == 0)))
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add_system_zone(sbi, ext4_group_first_block_no(sb, i),
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ext4_bg_num_gdb(sb, i) + 1);
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gdp = ext4_get_group_desc(sb, i, NULL);
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ret = add_system_zone(sbi, ext4_block_bitmap(sb, gdp), 1);
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if (ret)
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return ret;
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ret = add_system_zone(sbi, ext4_inode_bitmap(sb, gdp), 1);
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if (ret)
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return ret;
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ret = add_system_zone(sbi, ext4_inode_table(sb, gdp),
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sbi->s_itb_per_group);
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if (ret)
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return ret;
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}
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if (test_opt(sb, DEBUG))
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debug_print_tree(EXT4_SB(sb));
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return 0;
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}
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/* Called when the filesystem is unmounted */
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void ext4_release_system_zone(struct super_block *sb)
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{
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struct rb_node *n = EXT4_SB(sb)->system_blks.rb_node;
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struct rb_node *parent;
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struct ext4_system_zone *entry;
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while (n) {
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/* Do the node's children first */
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if (n->rb_left) {
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n = n->rb_left;
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continue;
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}
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if (n->rb_right) {
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n = n->rb_right;
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continue;
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}
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/*
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* The node has no children; free it, and then zero
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* out parent's link to it. Finally go to the
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* beginning of the loop and try to free the parent
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* node.
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*/
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parent = rb_parent(n);
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entry = rb_entry(n, struct ext4_system_zone, node);
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kmem_cache_free(ext4_system_zone_cachep, entry);
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if (!parent)
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EXT4_SB(sb)->system_blks = RB_ROOT;
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else if (parent->rb_left == n)
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parent->rb_left = NULL;
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else if (parent->rb_right == n)
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parent->rb_right = NULL;
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n = parent;
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}
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EXT4_SB(sb)->system_blks = RB_ROOT;
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}
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/*
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* Returns 1 if the passed-in block region (start_blk,
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* start_blk+count) is valid; 0 if some part of the block region
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* overlaps with filesystem metadata blocks.
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*/
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int ext4_data_block_valid(struct ext4_sb_info *sbi, ext4_fsblk_t start_blk,
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unsigned int count)
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{
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struct ext4_system_zone *entry;
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struct rb_node *n = sbi->system_blks.rb_node;
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if ((start_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
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(start_blk + count < start_blk) ||
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(start_blk + count > ext4_blocks_count(sbi->s_es))) {
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sbi->s_es->s_last_error_block = cpu_to_le64(start_blk);
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return 0;
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}
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while (n) {
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entry = rb_entry(n, struct ext4_system_zone, node);
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if (start_blk + count - 1 < entry->start_blk)
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n = n->rb_left;
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else if (start_blk >= (entry->start_blk + entry->count))
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n = n->rb_right;
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else {
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sbi->s_es->s_last_error_block = cpu_to_le64(start_blk);
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return 0;
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}
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}
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return 1;
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}
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