![Adrian Bunk](/assets/img/avatar_default.png)
The CONFIG_EXT{2,3}_CHECK options where were never available, and all they did was to implement a subset of e2fsck in the kernel. Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
627 lines
17 KiB
C
627 lines
17 KiB
C
/*
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* linux/fs/ext2/balloc.c
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*
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* Copyright (C) 1992, 1993, 1994, 1995
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* Remy Card (card@masi.ibp.fr)
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* Laboratoire MASI - Institut Blaise Pascal
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* Universite Pierre et Marie Curie (Paris VI)
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*
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* Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993
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* Big-endian to little-endian byte-swapping/bitmaps by
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* David S. Miller (davem@caip.rutgers.edu), 1995
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*/
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#include <linux/config.h>
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#include "ext2.h"
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#include <linux/quotaops.h>
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#include <linux/sched.h>
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#include <linux/buffer_head.h>
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/*
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* balloc.c contains the blocks allocation and deallocation routines
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*/
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/*
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* The free blocks are managed by bitmaps. A file system contains several
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* blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
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* block for inodes, N blocks for the inode table and data blocks.
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*
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* The file system contains group descriptors which are located after the
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* super block. Each descriptor contains the number of the bitmap block and
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* the free blocks count in the block. The descriptors are loaded in memory
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* when a file system is mounted (see ext2_read_super).
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*/
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#define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1)
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struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb,
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unsigned int block_group,
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struct buffer_head ** bh)
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{
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unsigned long group_desc;
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unsigned long offset;
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struct ext2_group_desc * desc;
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struct ext2_sb_info *sbi = EXT2_SB(sb);
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if (block_group >= sbi->s_groups_count) {
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ext2_error (sb, "ext2_get_group_desc",
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"block_group >= groups_count - "
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"block_group = %d, groups_count = %lu",
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block_group, sbi->s_groups_count);
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return NULL;
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}
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group_desc = block_group >> EXT2_DESC_PER_BLOCK_BITS(sb);
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offset = block_group & (EXT2_DESC_PER_BLOCK(sb) - 1);
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if (!sbi->s_group_desc[group_desc]) {
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ext2_error (sb, "ext2_get_group_desc",
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"Group descriptor not loaded - "
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"block_group = %d, group_desc = %lu, desc = %lu",
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block_group, group_desc, offset);
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return NULL;
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}
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desc = (struct ext2_group_desc *) sbi->s_group_desc[group_desc]->b_data;
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if (bh)
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*bh = sbi->s_group_desc[group_desc];
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return desc + offset;
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}
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/*
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* Read the bitmap for a given block_group, reading into the specified
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* slot in the superblock's bitmap cache.
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*
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* Return buffer_head on success or NULL in case of failure.
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*/
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static struct buffer_head *
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read_block_bitmap(struct super_block *sb, unsigned int block_group)
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{
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struct ext2_group_desc * desc;
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struct buffer_head * bh = NULL;
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desc = ext2_get_group_desc (sb, block_group, NULL);
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if (!desc)
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goto error_out;
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bh = sb_bread(sb, le32_to_cpu(desc->bg_block_bitmap));
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if (!bh)
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ext2_error (sb, "read_block_bitmap",
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"Cannot read block bitmap - "
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"block_group = %d, block_bitmap = %u",
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block_group, le32_to_cpu(desc->bg_block_bitmap));
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error_out:
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return bh;
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}
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/*
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* Set sb->s_dirt here because the superblock was "logically" altered. We
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* need to recalculate its free blocks count and flush it out.
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*/
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static int reserve_blocks(struct super_block *sb, int count)
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{
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struct ext2_sb_info *sbi = EXT2_SB(sb);
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struct ext2_super_block *es = sbi->s_es;
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unsigned free_blocks;
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unsigned root_blocks;
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free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
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root_blocks = le32_to_cpu(es->s_r_blocks_count);
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if (free_blocks < count)
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count = free_blocks;
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if (free_blocks < root_blocks + count && !capable(CAP_SYS_RESOURCE) &&
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sbi->s_resuid != current->fsuid &&
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(sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) {
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/*
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* We are too close to reserve and we are not privileged.
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* Can we allocate anything at all?
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*/
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if (free_blocks > root_blocks)
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count = free_blocks - root_blocks;
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else
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return 0;
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}
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percpu_counter_mod(&sbi->s_freeblocks_counter, -count);
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sb->s_dirt = 1;
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return count;
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}
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static void release_blocks(struct super_block *sb, int count)
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{
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if (count) {
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struct ext2_sb_info *sbi = EXT2_SB(sb);
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percpu_counter_mod(&sbi->s_freeblocks_counter, count);
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sb->s_dirt = 1;
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}
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}
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static int group_reserve_blocks(struct ext2_sb_info *sbi, int group_no,
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struct ext2_group_desc *desc, struct buffer_head *bh, int count)
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{
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unsigned free_blocks;
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if (!desc->bg_free_blocks_count)
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return 0;
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spin_lock(sb_bgl_lock(sbi, group_no));
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free_blocks = le16_to_cpu(desc->bg_free_blocks_count);
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if (free_blocks < count)
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count = free_blocks;
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desc->bg_free_blocks_count = cpu_to_le16(free_blocks - count);
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spin_unlock(sb_bgl_lock(sbi, group_no));
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mark_buffer_dirty(bh);
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return count;
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}
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static void group_release_blocks(struct super_block *sb, int group_no,
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struct ext2_group_desc *desc, struct buffer_head *bh, int count)
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{
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if (count) {
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struct ext2_sb_info *sbi = EXT2_SB(sb);
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unsigned free_blocks;
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spin_lock(sb_bgl_lock(sbi, group_no));
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free_blocks = le16_to_cpu(desc->bg_free_blocks_count);
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desc->bg_free_blocks_count = cpu_to_le16(free_blocks + count);
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spin_unlock(sb_bgl_lock(sbi, group_no));
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sb->s_dirt = 1;
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mark_buffer_dirty(bh);
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}
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}
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/* Free given blocks, update quota and i_blocks field */
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void ext2_free_blocks (struct inode * inode, unsigned long block,
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unsigned long count)
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{
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struct buffer_head *bitmap_bh = NULL;
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struct buffer_head * bh2;
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unsigned long block_group;
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unsigned long bit;
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unsigned long i;
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unsigned long overflow;
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struct super_block * sb = inode->i_sb;
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struct ext2_sb_info * sbi = EXT2_SB(sb);
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struct ext2_group_desc * desc;
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struct ext2_super_block * es = sbi->s_es;
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unsigned freed = 0, group_freed;
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if (block < le32_to_cpu(es->s_first_data_block) ||
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block + count < block ||
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block + count > le32_to_cpu(es->s_blocks_count)) {
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ext2_error (sb, "ext2_free_blocks",
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"Freeing blocks not in datazone - "
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"block = %lu, count = %lu", block, count);
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goto error_return;
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}
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ext2_debug ("freeing block(s) %lu-%lu\n", block, block + count - 1);
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do_more:
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overflow = 0;
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block_group = (block - le32_to_cpu(es->s_first_data_block)) /
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EXT2_BLOCKS_PER_GROUP(sb);
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bit = (block - le32_to_cpu(es->s_first_data_block)) %
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EXT2_BLOCKS_PER_GROUP(sb);
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/*
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* Check to see if we are freeing blocks across a group
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* boundary.
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*/
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if (bit + count > EXT2_BLOCKS_PER_GROUP(sb)) {
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overflow = bit + count - EXT2_BLOCKS_PER_GROUP(sb);
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count -= overflow;
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}
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brelse(bitmap_bh);
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bitmap_bh = read_block_bitmap(sb, block_group);
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if (!bitmap_bh)
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goto error_return;
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desc = ext2_get_group_desc (sb, block_group, &bh2);
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if (!desc)
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goto error_return;
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if (in_range (le32_to_cpu(desc->bg_block_bitmap), block, count) ||
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in_range (le32_to_cpu(desc->bg_inode_bitmap), block, count) ||
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in_range (block, le32_to_cpu(desc->bg_inode_table),
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sbi->s_itb_per_group) ||
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in_range (block + count - 1, le32_to_cpu(desc->bg_inode_table),
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sbi->s_itb_per_group))
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ext2_error (sb, "ext2_free_blocks",
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"Freeing blocks in system zones - "
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"Block = %lu, count = %lu",
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block, count);
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for (i = 0, group_freed = 0; i < count; i++) {
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if (!ext2_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
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bit + i, bitmap_bh->b_data)) {
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ext2_error(sb, __FUNCTION__,
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"bit already cleared for block %lu", block + i);
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} else {
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group_freed++;
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}
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}
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mark_buffer_dirty(bitmap_bh);
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if (sb->s_flags & MS_SYNCHRONOUS)
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sync_dirty_buffer(bitmap_bh);
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group_release_blocks(sb, block_group, desc, bh2, group_freed);
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freed += group_freed;
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if (overflow) {
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block += count;
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count = overflow;
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goto do_more;
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}
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error_return:
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brelse(bitmap_bh);
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release_blocks(sb, freed);
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DQUOT_FREE_BLOCK(inode, freed);
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}
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static int grab_block(spinlock_t *lock, char *map, unsigned size, int goal)
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{
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int k;
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char *p, *r;
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if (!ext2_test_bit(goal, map))
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goto got_it;
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repeat:
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if (goal) {
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/*
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* The goal was occupied; search forward for a free
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* block within the next XX blocks.
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*
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* end_goal is more or less random, but it has to be
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* less than EXT2_BLOCKS_PER_GROUP. Aligning up to the
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* next 64-bit boundary is simple..
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*/
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k = (goal + 63) & ~63;
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goal = ext2_find_next_zero_bit(map, k, goal);
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if (goal < k)
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goto got_it;
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/*
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* Search in the remainder of the current group.
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*/
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}
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p = map + (goal >> 3);
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r = memscan(p, 0, (size - goal + 7) >> 3);
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k = (r - map) << 3;
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if (k < size) {
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/*
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* We have succeeded in finding a free byte in the block
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* bitmap. Now search backwards to find the start of this
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* group of free blocks - won't take more than 7 iterations.
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*/
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for (goal = k; goal && !ext2_test_bit (goal - 1, map); goal--)
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;
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goto got_it;
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}
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k = ext2_find_next_zero_bit ((u32 *)map, size, goal);
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if (k < size) {
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goal = k;
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goto got_it;
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}
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return -1;
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got_it:
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if (ext2_set_bit_atomic(lock, goal, (void *) map))
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goto repeat;
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return goal;
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}
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/*
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* ext2_new_block uses a goal block to assist allocation. If the goal is
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* free, or there is a free block within 32 blocks of the goal, that block
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* is allocated. Otherwise a forward search is made for a free block; within
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* each block group the search first looks for an entire free byte in the block
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* bitmap, and then for any free bit if that fails.
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* This function also updates quota and i_blocks field.
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*/
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int ext2_new_block(struct inode *inode, unsigned long goal,
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u32 *prealloc_count, u32 *prealloc_block, int *err)
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{
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struct buffer_head *bitmap_bh = NULL;
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struct buffer_head *gdp_bh; /* bh2 */
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struct ext2_group_desc *desc;
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int group_no; /* i */
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int ret_block; /* j */
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int group_idx; /* k */
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int target_block; /* tmp */
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int block = 0;
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struct super_block *sb = inode->i_sb;
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struct ext2_sb_info *sbi = EXT2_SB(sb);
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struct ext2_super_block *es = sbi->s_es;
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unsigned group_size = EXT2_BLOCKS_PER_GROUP(sb);
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unsigned prealloc_goal = es->s_prealloc_blocks;
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unsigned group_alloc = 0, es_alloc, dq_alloc;
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int nr_scanned_groups;
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if (!prealloc_goal--)
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prealloc_goal = EXT2_DEFAULT_PREALLOC_BLOCKS - 1;
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if (!prealloc_count || *prealloc_count)
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prealloc_goal = 0;
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if (DQUOT_ALLOC_BLOCK(inode, 1)) {
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*err = -EDQUOT;
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goto out;
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}
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while (prealloc_goal && DQUOT_PREALLOC_BLOCK(inode, prealloc_goal))
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prealloc_goal--;
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dq_alloc = prealloc_goal + 1;
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es_alloc = reserve_blocks(sb, dq_alloc);
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if (!es_alloc) {
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*err = -ENOSPC;
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goto out_dquot;
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}
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ext2_debug ("goal=%lu.\n", goal);
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if (goal < le32_to_cpu(es->s_first_data_block) ||
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goal >= le32_to_cpu(es->s_blocks_count))
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goal = le32_to_cpu(es->s_first_data_block);
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group_no = (goal - le32_to_cpu(es->s_first_data_block)) / group_size;
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desc = ext2_get_group_desc (sb, group_no, &gdp_bh);
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if (!desc) {
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/*
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* gdp_bh may still be uninitialised. But group_release_blocks
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* will not touch it because group_alloc is zero.
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*/
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goto io_error;
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}
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group_alloc = group_reserve_blocks(sbi, group_no, desc,
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gdp_bh, es_alloc);
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if (group_alloc) {
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ret_block = ((goal - le32_to_cpu(es->s_first_data_block)) %
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group_size);
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brelse(bitmap_bh);
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bitmap_bh = read_block_bitmap(sb, group_no);
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if (!bitmap_bh)
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goto io_error;
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ext2_debug("goal is at %d:%d.\n", group_no, ret_block);
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ret_block = grab_block(sb_bgl_lock(sbi, group_no),
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bitmap_bh->b_data, group_size, ret_block);
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if (ret_block >= 0)
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goto got_block;
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group_release_blocks(sb, group_no, desc, gdp_bh, group_alloc);
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group_alloc = 0;
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}
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ext2_debug ("Bit not found in block group %d.\n", group_no);
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/*
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* Now search the rest of the groups. We assume that
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* i and desc correctly point to the last group visited.
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*/
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nr_scanned_groups = 0;
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retry:
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for (group_idx = 0; !group_alloc &&
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group_idx < sbi->s_groups_count; group_idx++) {
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group_no++;
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if (group_no >= sbi->s_groups_count)
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group_no = 0;
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desc = ext2_get_group_desc(sb, group_no, &gdp_bh);
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if (!desc)
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goto io_error;
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group_alloc = group_reserve_blocks(sbi, group_no, desc,
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gdp_bh, es_alloc);
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}
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if (!group_alloc) {
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*err = -ENOSPC;
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goto out_release;
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}
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brelse(bitmap_bh);
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bitmap_bh = read_block_bitmap(sb, group_no);
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if (!bitmap_bh)
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goto io_error;
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ret_block = grab_block(sb_bgl_lock(sbi, group_no), bitmap_bh->b_data,
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group_size, 0);
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if (ret_block < 0) {
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/*
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* If a free block counter is corrupted we can loop inifintely.
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* Detect that here.
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*/
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nr_scanned_groups++;
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if (nr_scanned_groups > 2 * sbi->s_groups_count) {
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ext2_error(sb, "ext2_new_block",
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"corrupted free blocks counters");
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goto io_error;
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}
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/*
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* Someone else grabbed the last free block in this blockgroup
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* before us. Retry the scan.
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*/
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group_release_blocks(sb, group_no, desc, gdp_bh, group_alloc);
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group_alloc = 0;
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goto retry;
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}
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got_block:
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ext2_debug("using block group %d(%d)\n",
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group_no, desc->bg_free_blocks_count);
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target_block = ret_block + group_no * group_size +
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le32_to_cpu(es->s_first_data_block);
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if (target_block == le32_to_cpu(desc->bg_block_bitmap) ||
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target_block == le32_to_cpu(desc->bg_inode_bitmap) ||
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in_range(target_block, le32_to_cpu(desc->bg_inode_table),
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sbi->s_itb_per_group))
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ext2_error (sb, "ext2_new_block",
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"Allocating block in system zone - "
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"block = %u", target_block);
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if (target_block >= le32_to_cpu(es->s_blocks_count)) {
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ext2_error (sb, "ext2_new_block",
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"block(%d) >= blocks count(%d) - "
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"block_group = %d, es == %p ", ret_block,
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le32_to_cpu(es->s_blocks_count), group_no, es);
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goto io_error;
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}
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block = target_block;
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/* OK, we _had_ allocated something */
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ext2_debug("found bit %d\n", ret_block);
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|
|
dq_alloc--;
|
|
es_alloc--;
|
|
group_alloc--;
|
|
|
|
/*
|
|
* Do block preallocation now if required.
|
|
*/
|
|
write_lock(&EXT2_I(inode)->i_meta_lock);
|
|
if (group_alloc && !*prealloc_count) {
|
|
unsigned n;
|
|
|
|
for (n = 0; n < group_alloc && ++ret_block < group_size; n++) {
|
|
if (ext2_set_bit_atomic(sb_bgl_lock(sbi, group_no),
|
|
ret_block,
|
|
(void*) bitmap_bh->b_data))
|
|
break;
|
|
}
|
|
*prealloc_block = block + 1;
|
|
*prealloc_count = n;
|
|
es_alloc -= n;
|
|
dq_alloc -= n;
|
|
group_alloc -= n;
|
|
}
|
|
write_unlock(&EXT2_I(inode)->i_meta_lock);
|
|
|
|
mark_buffer_dirty(bitmap_bh);
|
|
if (sb->s_flags & MS_SYNCHRONOUS)
|
|
sync_dirty_buffer(bitmap_bh);
|
|
|
|
ext2_debug ("allocating block %d. ", block);
|
|
|
|
*err = 0;
|
|
out_release:
|
|
group_release_blocks(sb, group_no, desc, gdp_bh, group_alloc);
|
|
release_blocks(sb, es_alloc);
|
|
out_dquot:
|
|
DQUOT_FREE_BLOCK(inode, dq_alloc);
|
|
out:
|
|
brelse(bitmap_bh);
|
|
return block;
|
|
|
|
io_error:
|
|
*err = -EIO;
|
|
goto out_release;
|
|
}
|
|
|
|
unsigned long ext2_count_free_blocks (struct super_block * sb)
|
|
{
|
|
struct ext2_group_desc * desc;
|
|
unsigned long desc_count = 0;
|
|
int i;
|
|
#ifdef EXT2FS_DEBUG
|
|
unsigned long bitmap_count, x;
|
|
struct ext2_super_block *es;
|
|
|
|
lock_super (sb);
|
|
es = EXT2_SB(sb)->s_es;
|
|
desc_count = 0;
|
|
bitmap_count = 0;
|
|
desc = NULL;
|
|
for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
|
|
struct buffer_head *bitmap_bh;
|
|
desc = ext2_get_group_desc (sb, i, NULL);
|
|
if (!desc)
|
|
continue;
|
|
desc_count += le16_to_cpu(desc->bg_free_blocks_count);
|
|
bitmap_bh = read_block_bitmap(sb, i);
|
|
if (!bitmap_bh)
|
|
continue;
|
|
|
|
x = ext2_count_free(bitmap_bh, sb->s_blocksize);
|
|
printk ("group %d: stored = %d, counted = %lu\n",
|
|
i, le16_to_cpu(desc->bg_free_blocks_count), x);
|
|
bitmap_count += x;
|
|
brelse(bitmap_bh);
|
|
}
|
|
printk("ext2_count_free_blocks: stored = %lu, computed = %lu, %lu\n",
|
|
(long)le32_to_cpu(es->s_free_blocks_count),
|
|
desc_count, bitmap_count);
|
|
unlock_super (sb);
|
|
return bitmap_count;
|
|
#else
|
|
for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
|
|
desc = ext2_get_group_desc (sb, i, NULL);
|
|
if (!desc)
|
|
continue;
|
|
desc_count += le16_to_cpu(desc->bg_free_blocks_count);
|
|
}
|
|
return desc_count;
|
|
#endif
|
|
}
|
|
|
|
static inline int
|
|
block_in_use(unsigned long block, struct super_block *sb, unsigned char *map)
|
|
{
|
|
return ext2_test_bit ((block -
|
|
le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block)) %
|
|
EXT2_BLOCKS_PER_GROUP(sb), map);
|
|
}
|
|
|
|
static inline int test_root(int a, int b)
|
|
{
|
|
int num = b;
|
|
|
|
while (a > num)
|
|
num *= b;
|
|
return num == a;
|
|
}
|
|
|
|
static int ext2_group_sparse(int group)
|
|
{
|
|
if (group <= 1)
|
|
return 1;
|
|
return (test_root(group, 3) || test_root(group, 5) ||
|
|
test_root(group, 7));
|
|
}
|
|
|
|
/**
|
|
* ext2_bg_has_super - number of blocks used by the superblock in group
|
|
* @sb: superblock for filesystem
|
|
* @group: group number to check
|
|
*
|
|
* Return the number of blocks used by the superblock (primary or backup)
|
|
* in this group. Currently this will be only 0 or 1.
|
|
*/
|
|
int ext2_bg_has_super(struct super_block *sb, int group)
|
|
{
|
|
if (EXT2_HAS_RO_COMPAT_FEATURE(sb,EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)&&
|
|
!ext2_group_sparse(group))
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
/**
|
|
* ext2_bg_num_gdb - number of blocks used by the group table in group
|
|
* @sb: superblock for filesystem
|
|
* @group: group number to check
|
|
*
|
|
* Return the number of blocks used by the group descriptor table
|
|
* (primary or backup) in this group. In the future there may be a
|
|
* different number of descriptor blocks in each group.
|
|
*/
|
|
unsigned long ext2_bg_num_gdb(struct super_block *sb, int group)
|
|
{
|
|
if (EXT2_HAS_RO_COMPAT_FEATURE(sb,EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)&&
|
|
!ext2_group_sparse(group))
|
|
return 0;
|
|
return EXT2_SB(sb)->s_gdb_count;
|
|
}
|
|
|