1541 lines
44 KiB
C
1541 lines
44 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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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 "ext2.h"
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#include <linux/quotaops.h>
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#include <linux/slab.h>
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#include <linux/sched.h>
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#include <linux/cred.h>
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#include <linux/buffer_head.h>
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#include <linux/capability.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_fill_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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WARN(1, "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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WARN(1, "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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static int ext2_valid_block_bitmap(struct super_block *sb,
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struct ext2_group_desc *desc,
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unsigned int block_group,
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struct buffer_head *bh)
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{
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ext2_grpblk_t offset;
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ext2_grpblk_t next_zero_bit;
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ext2_fsblk_t bitmap_blk;
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ext2_fsblk_t group_first_block;
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group_first_block = ext2_group_first_block_no(sb, block_group);
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/* check whether block bitmap block number is set */
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bitmap_blk = le32_to_cpu(desc->bg_block_bitmap);
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offset = bitmap_blk - group_first_block;
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if (!ext2_test_bit(offset, bh->b_data))
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/* bad block bitmap */
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goto err_out;
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/* check whether the inode bitmap block number is set */
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bitmap_blk = le32_to_cpu(desc->bg_inode_bitmap);
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offset = bitmap_blk - group_first_block;
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if (!ext2_test_bit(offset, bh->b_data))
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/* bad block bitmap */
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goto err_out;
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/* check whether the inode table block number is set */
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bitmap_blk = le32_to_cpu(desc->bg_inode_table);
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offset = bitmap_blk - group_first_block;
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next_zero_bit = ext2_find_next_zero_bit(bh->b_data,
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offset + EXT2_SB(sb)->s_itb_per_group,
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offset);
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if (next_zero_bit >= offset + EXT2_SB(sb)->s_itb_per_group)
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/* good bitmap for inode tables */
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return 1;
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err_out:
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ext2_error(sb, __func__,
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"Invalid block bitmap - "
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"block_group = %d, block = %lu",
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block_group, bitmap_blk);
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return 0;
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}
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/*
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* Read the bitmap for a given block_group,and validate the
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* bits for block/inode/inode tables are set in the bitmaps
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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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ext2_fsblk_t bitmap_blk;
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int ret;
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desc = ext2_get_group_desc(sb, block_group, NULL);
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if (!desc)
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return NULL;
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bitmap_blk = le32_to_cpu(desc->bg_block_bitmap);
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bh = sb_getblk(sb, bitmap_blk);
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if (unlikely(!bh)) {
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ext2_error(sb, __func__,
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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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return NULL;
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}
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ret = bh_read(bh, 0);
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if (ret > 0)
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return bh;
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if (ret < 0) {
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brelse(bh);
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ext2_error(sb, __func__,
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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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return NULL;
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}
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ext2_valid_block_bitmap(sb, desc, block_group, bh);
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/*
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* file system mounted not to panic on error, continue with corrupt
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* bitmap
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*/
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return bh;
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}
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static void group_adjust_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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mark_buffer_dirty(bh);
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}
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}
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/*
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* The reservation window structure operations
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* --------------------------------------------
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* Operations include:
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* dump, find, add, remove, is_empty, find_next_reservable_window, etc.
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*
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* We use a red-black tree to represent per-filesystem reservation
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* windows.
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*
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*/
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/**
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* __rsv_window_dump() -- Dump the filesystem block allocation reservation map
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* @root: root of per-filesystem reservation rb tree
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* @verbose: verbose mode
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* @fn: function which wishes to dump the reservation map
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*
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* If verbose is turned on, it will print the whole block reservation
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* windows(start, end). Otherwise, it will only print out the "bad" windows,
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* those windows that overlap with their immediate neighbors.
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*/
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#if 1
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static void __rsv_window_dump(struct rb_root *root, int verbose,
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const char *fn)
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{
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struct rb_node *n;
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struct ext2_reserve_window_node *rsv, *prev;
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int bad;
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restart:
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n = rb_first(root);
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bad = 0;
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prev = NULL;
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printk("Block Allocation Reservation Windows Map (%s):\n", fn);
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while (n) {
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rsv = rb_entry(n, struct ext2_reserve_window_node, rsv_node);
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if (verbose)
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printk("reservation window 0x%p "
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"start: %lu, end: %lu\n",
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rsv, rsv->rsv_start, rsv->rsv_end);
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if (rsv->rsv_start && rsv->rsv_start >= rsv->rsv_end) {
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printk("Bad reservation %p (start >= end)\n",
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rsv);
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bad = 1;
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}
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if (prev && prev->rsv_end >= rsv->rsv_start) {
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printk("Bad reservation %p (prev->end >= start)\n",
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rsv);
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bad = 1;
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}
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if (bad) {
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if (!verbose) {
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printk("Restarting reservation walk in verbose mode\n");
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verbose = 1;
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goto restart;
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}
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}
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n = rb_next(n);
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prev = rsv;
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}
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printk("Window map complete.\n");
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BUG_ON(bad);
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}
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#define rsv_window_dump(root, verbose) \
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__rsv_window_dump((root), (verbose), __func__)
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#else
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#define rsv_window_dump(root, verbose) do {} while (0)
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#endif
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/**
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* goal_in_my_reservation()
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* @rsv: inode's reservation window
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* @grp_goal: given goal block relative to the allocation block group
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* @group: the current allocation block group
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* @sb: filesystem super block
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*
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* Test if the given goal block (group relative) is within the file's
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* own block reservation window range.
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*
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* If the reservation window is outside the goal allocation group, return 0;
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* grp_goal (given goal block) could be -1, which means no specific
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* goal block. In this case, always return 1.
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* If the goal block is within the reservation window, return 1;
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* otherwise, return 0;
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*/
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static int
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goal_in_my_reservation(struct ext2_reserve_window *rsv, ext2_grpblk_t grp_goal,
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unsigned int group, struct super_block * sb)
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{
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ext2_fsblk_t group_first_block, group_last_block;
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group_first_block = ext2_group_first_block_no(sb, group);
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group_last_block = ext2_group_last_block_no(sb, group);
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if ((rsv->_rsv_start > group_last_block) ||
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(rsv->_rsv_end < group_first_block))
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return 0;
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if ((grp_goal >= 0) && ((grp_goal + group_first_block < rsv->_rsv_start)
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|| (grp_goal + group_first_block > rsv->_rsv_end)))
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return 0;
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return 1;
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}
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/**
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* search_reserve_window()
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* @root: root of reservation tree
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* @goal: target allocation block
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*
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* Find the reserved window which includes the goal, or the previous one
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* if the goal is not in any window.
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* Returns NULL if there are no windows or if all windows start after the goal.
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*/
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static struct ext2_reserve_window_node *
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search_reserve_window(struct rb_root *root, ext2_fsblk_t goal)
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{
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struct rb_node *n = root->rb_node;
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struct ext2_reserve_window_node *rsv;
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if (!n)
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return NULL;
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do {
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rsv = rb_entry(n, struct ext2_reserve_window_node, rsv_node);
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if (goal < rsv->rsv_start)
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n = n->rb_left;
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else if (goal > rsv->rsv_end)
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n = n->rb_right;
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else
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return rsv;
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} while (n);
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/*
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* We've fallen off the end of the tree: the goal wasn't inside
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* any particular node. OK, the previous node must be to one
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* side of the interval containing the goal. If it's the RHS,
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* we need to back up one.
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*/
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if (rsv->rsv_start > goal) {
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n = rb_prev(&rsv->rsv_node);
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rsv = rb_entry(n, struct ext2_reserve_window_node, rsv_node);
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}
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return rsv;
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}
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/*
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* ext2_rsv_window_add() -- Insert a window to the block reservation rb tree.
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* @sb: super block
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* @rsv: reservation window to add
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*
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* Must be called with rsv_lock held.
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*/
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void ext2_rsv_window_add(struct super_block *sb,
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struct ext2_reserve_window_node *rsv)
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{
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struct rb_root *root = &EXT2_SB(sb)->s_rsv_window_root;
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struct rb_node *node = &rsv->rsv_node;
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ext2_fsblk_t start = rsv->rsv_start;
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struct rb_node ** p = &root->rb_node;
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struct rb_node * parent = NULL;
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struct ext2_reserve_window_node *this;
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while (*p)
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{
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parent = *p;
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this = rb_entry(parent, struct ext2_reserve_window_node, rsv_node);
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if (start < this->rsv_start)
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p = &(*p)->rb_left;
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else if (start > this->rsv_end)
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p = &(*p)->rb_right;
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else {
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rsv_window_dump(root, 1);
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BUG();
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}
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}
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rb_link_node(node, parent, p);
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rb_insert_color(node, root);
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}
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/**
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* rsv_window_remove() -- unlink a window from the reservation rb tree
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* @sb: super block
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* @rsv: reservation window to remove
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*
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* Mark the block reservation window as not allocated, and unlink it
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* from the filesystem reservation window rb tree. Must be called with
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* rsv_lock held.
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*/
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static void rsv_window_remove(struct super_block *sb,
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struct ext2_reserve_window_node *rsv)
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{
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rsv->rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
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rsv->rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
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rsv->rsv_alloc_hit = 0;
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rb_erase(&rsv->rsv_node, &EXT2_SB(sb)->s_rsv_window_root);
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}
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/*
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* rsv_is_empty() -- Check if the reservation window is allocated.
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* @rsv: given reservation window to check
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*
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* returns 1 if the end block is EXT2_RESERVE_WINDOW_NOT_ALLOCATED.
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*/
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static inline int rsv_is_empty(struct ext2_reserve_window *rsv)
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{
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/* a valid reservation end block could not be 0 */
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return (rsv->_rsv_end == EXT2_RESERVE_WINDOW_NOT_ALLOCATED);
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}
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/**
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* ext2_init_block_alloc_info()
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* @inode: file inode structure
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*
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* Allocate and initialize the reservation window structure, and
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* link the window to the ext2 inode structure at last
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*
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* The reservation window structure is only dynamically allocated
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* and linked to ext2 inode the first time the open file
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* needs a new block. So, before every ext2_new_block(s) call, for
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* regular files, we should check whether the reservation window
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* structure exists or not. In the latter case, this function is called.
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* Fail to do so will result in block reservation being turned off for that
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* open file.
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*
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* This function is called from ext2_get_blocks_handle(), also called
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* when setting the reservation window size through ioctl before the file
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* is open for write (needs block allocation).
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*
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* Needs truncate_mutex protection prior to calling this function.
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*/
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void ext2_init_block_alloc_info(struct inode *inode)
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{
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struct ext2_inode_info *ei = EXT2_I(inode);
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struct ext2_block_alloc_info *block_i;
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struct super_block *sb = inode->i_sb;
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block_i = kmalloc(sizeof(*block_i), GFP_NOFS);
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if (block_i) {
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struct ext2_reserve_window_node *rsv = &block_i->rsv_window_node;
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rsv->rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
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rsv->rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
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/*
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* if filesystem is mounted with NORESERVATION, the goal
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* reservation window size is set to zero to indicate
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* block reservation is off
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*/
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if (!test_opt(sb, RESERVATION))
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rsv->rsv_goal_size = 0;
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else
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rsv->rsv_goal_size = EXT2_DEFAULT_RESERVE_BLOCKS;
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rsv->rsv_alloc_hit = 0;
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block_i->last_alloc_logical_block = 0;
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block_i->last_alloc_physical_block = 0;
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}
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ei->i_block_alloc_info = block_i;
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}
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/**
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* ext2_discard_reservation()
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* @inode: inode
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*
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* Discard(free) block reservation window on last file close, or truncate
|
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* or at last iput().
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*
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* It is being called in three cases:
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* ext2_release_file(): last writer closes the file
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* ext2_clear_inode(): last iput(), when nobody links to this file.
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* ext2_truncate(): when the block indirect map is about to change.
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*/
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void ext2_discard_reservation(struct inode *inode)
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{
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struct ext2_inode_info *ei = EXT2_I(inode);
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struct ext2_block_alloc_info *block_i = ei->i_block_alloc_info;
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struct ext2_reserve_window_node *rsv;
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spinlock_t *rsv_lock = &EXT2_SB(inode->i_sb)->s_rsv_window_lock;
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if (!block_i)
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return;
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rsv = &block_i->rsv_window_node;
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if (!rsv_is_empty(&rsv->rsv_window)) {
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spin_lock(rsv_lock);
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if (!rsv_is_empty(&rsv->rsv_window))
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rsv_window_remove(inode->i_sb, rsv);
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spin_unlock(rsv_lock);
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}
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}
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|
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/**
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* ext2_free_blocks() -- Free given blocks and update quota and i_blocks
|
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* @inode: inode
|
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* @block: start physical block to free
|
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* @count: number of blocks to free
|
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*/
|
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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;
|
|
struct ext2_super_block * es = sbi->s_es;
|
|
unsigned freed = 0, group_freed;
|
|
|
|
if (!ext2_data_block_valid(sbi, block, count)) {
|
|
ext2_error (sb, "ext2_free_blocks",
|
|
"Freeing blocks not in datazone - "
|
|
"block = %lu, count = %lu", block, count);
|
|
goto error_return;
|
|
}
|
|
|
|
ext2_debug ("freeing block(s) %lu-%lu\n", block, block + count - 1);
|
|
|
|
do_more:
|
|
overflow = 0;
|
|
block_group = (block - le32_to_cpu(es->s_first_data_block)) /
|
|
EXT2_BLOCKS_PER_GROUP(sb);
|
|
bit = (block - le32_to_cpu(es->s_first_data_block)) %
|
|
EXT2_BLOCKS_PER_GROUP(sb);
|
|
/*
|
|
* Check to see if we are freeing blocks across a group
|
|
* boundary.
|
|
*/
|
|
if (bit + count > EXT2_BLOCKS_PER_GROUP(sb)) {
|
|
overflow = bit + count - EXT2_BLOCKS_PER_GROUP(sb);
|
|
count -= overflow;
|
|
}
|
|
brelse(bitmap_bh);
|
|
bitmap_bh = read_block_bitmap(sb, block_group);
|
|
if (!bitmap_bh)
|
|
goto error_return;
|
|
|
|
desc = ext2_get_group_desc (sb, block_group, &bh2);
|
|
if (!desc)
|
|
goto error_return;
|
|
|
|
if (in_range (le32_to_cpu(desc->bg_block_bitmap), block, count) ||
|
|
in_range (le32_to_cpu(desc->bg_inode_bitmap), block, count) ||
|
|
in_range (block, le32_to_cpu(desc->bg_inode_table),
|
|
sbi->s_itb_per_group) ||
|
|
in_range (block + count - 1, le32_to_cpu(desc->bg_inode_table),
|
|
sbi->s_itb_per_group)) {
|
|
ext2_error (sb, "ext2_free_blocks",
|
|
"Freeing blocks in system zones - "
|
|
"Block = %lu, count = %lu",
|
|
block, count);
|
|
goto error_return;
|
|
}
|
|
|
|
for (i = 0, group_freed = 0; i < count; i++) {
|
|
if (!ext2_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
|
|
bit + i, bitmap_bh->b_data)) {
|
|
ext2_error(sb, __func__,
|
|
"bit already cleared for block %lu", block + i);
|
|
} else {
|
|
group_freed++;
|
|
}
|
|
}
|
|
|
|
mark_buffer_dirty(bitmap_bh);
|
|
if (sb->s_flags & SB_SYNCHRONOUS)
|
|
sync_dirty_buffer(bitmap_bh);
|
|
|
|
group_adjust_blocks(sb, block_group, desc, bh2, group_freed);
|
|
freed += group_freed;
|
|
|
|
if (overflow) {
|
|
block += count;
|
|
count = overflow;
|
|
goto do_more;
|
|
}
|
|
error_return:
|
|
brelse(bitmap_bh);
|
|
if (freed) {
|
|
percpu_counter_add(&sbi->s_freeblocks_counter, freed);
|
|
dquot_free_block_nodirty(inode, freed);
|
|
mark_inode_dirty(inode);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* bitmap_search_next_usable_block()
|
|
* @start: the starting block (group relative) of the search
|
|
* @bh: bufferhead contains the block group bitmap
|
|
* @maxblocks: the ending block (group relative) of the reservation
|
|
*
|
|
* The bitmap search --- search forward through the actual bitmap on disk until
|
|
* we find a bit free.
|
|
*/
|
|
static ext2_grpblk_t
|
|
bitmap_search_next_usable_block(ext2_grpblk_t start, struct buffer_head *bh,
|
|
ext2_grpblk_t maxblocks)
|
|
{
|
|
ext2_grpblk_t next;
|
|
|
|
next = ext2_find_next_zero_bit(bh->b_data, maxblocks, start);
|
|
if (next >= maxblocks)
|
|
return -1;
|
|
return next;
|
|
}
|
|
|
|
/**
|
|
* find_next_usable_block()
|
|
* @start: the starting block (group relative) to find next
|
|
* allocatable block in bitmap.
|
|
* @bh: bufferhead contains the block group bitmap
|
|
* @maxblocks: the ending block (group relative) for the search
|
|
*
|
|
* Find an allocatable block in a bitmap. We perform the "most
|
|
* appropriate allocation" algorithm of looking for a free block near
|
|
* the initial goal; then for a free byte somewhere in the bitmap;
|
|
* then for any free bit in the bitmap.
|
|
*/
|
|
static ext2_grpblk_t
|
|
find_next_usable_block(int start, struct buffer_head *bh, int maxblocks)
|
|
{
|
|
ext2_grpblk_t here, next;
|
|
char *p, *r;
|
|
|
|
if (start > 0) {
|
|
/*
|
|
* The goal was occupied; search forward for a free
|
|
* block within the next XX blocks.
|
|
*
|
|
* end_goal is more or less random, but it has to be
|
|
* less than EXT2_BLOCKS_PER_GROUP. Aligning up to the
|
|
* next 64-bit boundary is simple..
|
|
*/
|
|
ext2_grpblk_t end_goal = (start + 63) & ~63;
|
|
if (end_goal > maxblocks)
|
|
end_goal = maxblocks;
|
|
here = ext2_find_next_zero_bit(bh->b_data, end_goal, start);
|
|
if (here < end_goal)
|
|
return here;
|
|
ext2_debug("Bit not found near goal\n");
|
|
}
|
|
|
|
here = start;
|
|
if (here < 0)
|
|
here = 0;
|
|
|
|
p = ((char *)bh->b_data) + (here >> 3);
|
|
r = memscan(p, 0, ((maxblocks + 7) >> 3) - (here >> 3));
|
|
next = (r - ((char *)bh->b_data)) << 3;
|
|
|
|
if (next < maxblocks && next >= here)
|
|
return next;
|
|
|
|
here = bitmap_search_next_usable_block(here, bh, maxblocks);
|
|
return here;
|
|
}
|
|
|
|
/**
|
|
* ext2_try_to_allocate()
|
|
* @sb: superblock
|
|
* @group: given allocation block group
|
|
* @bitmap_bh: bufferhead holds the block bitmap
|
|
* @grp_goal: given target block within the group
|
|
* @count: target number of blocks to allocate
|
|
* @my_rsv: reservation window
|
|
*
|
|
* Attempt to allocate blocks within a give range. Set the range of allocation
|
|
* first, then find the first free bit(s) from the bitmap (within the range),
|
|
* and at last, allocate the blocks by claiming the found free bit as allocated.
|
|
*
|
|
* To set the range of this allocation:
|
|
* if there is a reservation window, only try to allocate block(s)
|
|
* from the file's own reservation window;
|
|
* Otherwise, the allocation range starts from the give goal block,
|
|
* ends at the block group's last block.
|
|
*
|
|
* If we failed to allocate the desired block then we may end up crossing to a
|
|
* new bitmap.
|
|
*/
|
|
static int
|
|
ext2_try_to_allocate(struct super_block *sb, int group,
|
|
struct buffer_head *bitmap_bh, ext2_grpblk_t grp_goal,
|
|
unsigned long *count,
|
|
struct ext2_reserve_window *my_rsv)
|
|
{
|
|
ext2_fsblk_t group_first_block = ext2_group_first_block_no(sb, group);
|
|
ext2_fsblk_t group_last_block = ext2_group_last_block_no(sb, group);
|
|
ext2_grpblk_t start, end;
|
|
unsigned long num = 0;
|
|
|
|
start = 0;
|
|
end = group_last_block - group_first_block + 1;
|
|
/* we do allocation within the reservation window if we have a window */
|
|
if (my_rsv) {
|
|
if (my_rsv->_rsv_start >= group_first_block)
|
|
start = my_rsv->_rsv_start - group_first_block;
|
|
if (my_rsv->_rsv_end < group_last_block)
|
|
end = my_rsv->_rsv_end - group_first_block + 1;
|
|
if (grp_goal < start || grp_goal >= end)
|
|
grp_goal = -1;
|
|
}
|
|
BUG_ON(start > EXT2_BLOCKS_PER_GROUP(sb));
|
|
|
|
if (grp_goal < 0) {
|
|
grp_goal = find_next_usable_block(start, bitmap_bh, end);
|
|
if (grp_goal < 0)
|
|
goto fail_access;
|
|
if (!my_rsv) {
|
|
int i;
|
|
|
|
for (i = 0; i < 7 && grp_goal > start &&
|
|
!ext2_test_bit(grp_goal - 1,
|
|
bitmap_bh->b_data);
|
|
i++, grp_goal--)
|
|
;
|
|
}
|
|
}
|
|
|
|
for (; num < *count && grp_goal < end; grp_goal++) {
|
|
if (ext2_set_bit_atomic(sb_bgl_lock(EXT2_SB(sb), group),
|
|
grp_goal, bitmap_bh->b_data)) {
|
|
if (num == 0)
|
|
continue;
|
|
break;
|
|
}
|
|
num++;
|
|
}
|
|
|
|
if (num == 0)
|
|
goto fail_access;
|
|
|
|
*count = num;
|
|
return grp_goal - num;
|
|
fail_access:
|
|
return -1;
|
|
}
|
|
|
|
/**
|
|
* find_next_reservable_window():
|
|
* find a reservable space within the given range.
|
|
* It does not allocate the reservation window for now:
|
|
* alloc_new_reservation() will do the work later.
|
|
*
|
|
* @search_head: the head of the searching list;
|
|
* This is not necessarily the list head of the whole filesystem
|
|
*
|
|
* We have both head and start_block to assist the search
|
|
* for the reservable space. The list starts from head,
|
|
* but we will shift to the place where start_block is,
|
|
* then start from there, when looking for a reservable space.
|
|
*
|
|
* @sb: the super block.
|
|
*
|
|
* @start_block: the first block we consider to start the real search from
|
|
*
|
|
* @last_block:
|
|
* the maximum block number that our goal reservable space
|
|
* could start from. This is normally the last block in this
|
|
* group. The search will end when we found the start of next
|
|
* possible reservable space is out of this boundary.
|
|
* This could handle the cross boundary reservation window
|
|
* request.
|
|
*
|
|
* basically we search from the given range, rather than the whole
|
|
* reservation double linked list, (start_block, last_block)
|
|
* to find a free region that is of my size and has not
|
|
* been reserved.
|
|
*
|
|
*/
|
|
static int find_next_reservable_window(
|
|
struct ext2_reserve_window_node *search_head,
|
|
struct ext2_reserve_window_node *my_rsv,
|
|
struct super_block * sb,
|
|
ext2_fsblk_t start_block,
|
|
ext2_fsblk_t last_block)
|
|
{
|
|
struct rb_node *next;
|
|
struct ext2_reserve_window_node *rsv, *prev;
|
|
ext2_fsblk_t cur;
|
|
int size = my_rsv->rsv_goal_size;
|
|
|
|
/* TODO: make the start of the reservation window byte-aligned */
|
|
/* cur = *start_block & ~7;*/
|
|
cur = start_block;
|
|
rsv = search_head;
|
|
if (!rsv)
|
|
return -1;
|
|
|
|
while (1) {
|
|
if (cur <= rsv->rsv_end)
|
|
cur = rsv->rsv_end + 1;
|
|
|
|
/* TODO?
|
|
* in the case we could not find a reservable space
|
|
* that is what is expected, during the re-search, we could
|
|
* remember what's the largest reservable space we could have
|
|
* and return that one.
|
|
*
|
|
* For now it will fail if we could not find the reservable
|
|
* space with expected-size (or more)...
|
|
*/
|
|
if (cur > last_block)
|
|
return -1; /* fail */
|
|
|
|
prev = rsv;
|
|
next = rb_next(&rsv->rsv_node);
|
|
rsv = rb_entry(next,struct ext2_reserve_window_node,rsv_node);
|
|
|
|
/*
|
|
* Reached the last reservation, we can just append to the
|
|
* previous one.
|
|
*/
|
|
if (!next)
|
|
break;
|
|
|
|
if (cur + size <= rsv->rsv_start) {
|
|
/*
|
|
* Found a reserveable space big enough. We could
|
|
* have a reservation across the group boundary here
|
|
*/
|
|
break;
|
|
}
|
|
}
|
|
/*
|
|
* we come here either :
|
|
* when we reach the end of the whole list,
|
|
* and there is empty reservable space after last entry in the list.
|
|
* append it to the end of the list.
|
|
*
|
|
* or we found one reservable space in the middle of the list,
|
|
* return the reservation window that we could append to.
|
|
* succeed.
|
|
*/
|
|
|
|
if ((prev != my_rsv) && (!rsv_is_empty(&my_rsv->rsv_window)))
|
|
rsv_window_remove(sb, my_rsv);
|
|
|
|
/*
|
|
* Let's book the whole available window for now. We will check the
|
|
* disk bitmap later and then, if there are free blocks then we adjust
|
|
* the window size if it's larger than requested.
|
|
* Otherwise, we will remove this node from the tree next time
|
|
* call find_next_reservable_window.
|
|
*/
|
|
my_rsv->rsv_start = cur;
|
|
my_rsv->rsv_end = cur + size - 1;
|
|
my_rsv->rsv_alloc_hit = 0;
|
|
|
|
if (prev != my_rsv)
|
|
ext2_rsv_window_add(sb, my_rsv);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* alloc_new_reservation()--allocate a new reservation window
|
|
*
|
|
* To make a new reservation, we search part of the filesystem
|
|
* reservation list (the list that inside the group). We try to
|
|
* allocate a new reservation window near the allocation goal,
|
|
* or the beginning of the group, if there is no goal.
|
|
*
|
|
* We first find a reservable space after the goal, then from
|
|
* there, we check the bitmap for the first free block after
|
|
* it. If there is no free block until the end of group, then the
|
|
* whole group is full, we failed. Otherwise, check if the free
|
|
* block is inside the expected reservable space, if so, we
|
|
* succeed.
|
|
* If the first free block is outside the reservable space, then
|
|
* start from the first free block, we search for next available
|
|
* space, and go on.
|
|
*
|
|
* on succeed, a new reservation will be found and inserted into the list
|
|
* It contains at least one free block, and it does not overlap with other
|
|
* reservation windows.
|
|
*
|
|
* failed: we failed to find a reservation window in this group
|
|
*
|
|
* @my_rsv: the reservation
|
|
*
|
|
* @grp_goal: The goal (group-relative). It is where the search for a
|
|
* free reservable space should start from.
|
|
* if we have a goal(goal >0 ), then start from there,
|
|
* no goal(goal = -1), we start from the first block
|
|
* of the group.
|
|
*
|
|
* @sb: the super block
|
|
* @group: the group we are trying to allocate in
|
|
* @bitmap_bh: the block group block bitmap
|
|
*
|
|
*/
|
|
static int alloc_new_reservation(struct ext2_reserve_window_node *my_rsv,
|
|
ext2_grpblk_t grp_goal, struct super_block *sb,
|
|
unsigned int group, struct buffer_head *bitmap_bh)
|
|
{
|
|
struct ext2_reserve_window_node *search_head;
|
|
ext2_fsblk_t group_first_block, group_end_block, start_block;
|
|
ext2_grpblk_t first_free_block;
|
|
struct rb_root *fs_rsv_root = &EXT2_SB(sb)->s_rsv_window_root;
|
|
unsigned long size;
|
|
int ret;
|
|
spinlock_t *rsv_lock = &EXT2_SB(sb)->s_rsv_window_lock;
|
|
|
|
group_first_block = ext2_group_first_block_no(sb, group);
|
|
group_end_block = ext2_group_last_block_no(sb, group);
|
|
|
|
if (grp_goal < 0)
|
|
start_block = group_first_block;
|
|
else
|
|
start_block = grp_goal + group_first_block;
|
|
|
|
size = my_rsv->rsv_goal_size;
|
|
|
|
if (!rsv_is_empty(&my_rsv->rsv_window)) {
|
|
/*
|
|
* if the old reservation is cross group boundary
|
|
* and if the goal is inside the old reservation window,
|
|
* we will come here when we just failed to allocate from
|
|
* the first part of the window. We still have another part
|
|
* that belongs to the next group. In this case, there is no
|
|
* point to discard our window and try to allocate a new one
|
|
* in this group(which will fail). we should
|
|
* keep the reservation window, just simply move on.
|
|
*
|
|
* Maybe we could shift the start block of the reservation
|
|
* window to the first block of next group.
|
|
*/
|
|
|
|
if ((my_rsv->rsv_start <= group_end_block) &&
|
|
(my_rsv->rsv_end > group_end_block) &&
|
|
(start_block >= my_rsv->rsv_start))
|
|
return -1;
|
|
|
|
if ((my_rsv->rsv_alloc_hit >
|
|
(my_rsv->rsv_end - my_rsv->rsv_start + 1) / 2)) {
|
|
/*
|
|
* if the previously allocation hit ratio is
|
|
* greater than 1/2, then we double the size of
|
|
* the reservation window the next time,
|
|
* otherwise we keep the same size window
|
|
*/
|
|
size = size * 2;
|
|
if (size > EXT2_MAX_RESERVE_BLOCKS)
|
|
size = EXT2_MAX_RESERVE_BLOCKS;
|
|
my_rsv->rsv_goal_size= size;
|
|
}
|
|
}
|
|
|
|
spin_lock(rsv_lock);
|
|
/*
|
|
* shift the search start to the window near the goal block
|
|
*/
|
|
search_head = search_reserve_window(fs_rsv_root, start_block);
|
|
|
|
/*
|
|
* find_next_reservable_window() simply finds a reservable window
|
|
* inside the given range(start_block, group_end_block).
|
|
*
|
|
* To make sure the reservation window has a free bit inside it, we
|
|
* need to check the bitmap after we found a reservable window.
|
|
*/
|
|
retry:
|
|
ret = find_next_reservable_window(search_head, my_rsv, sb,
|
|
start_block, group_end_block);
|
|
|
|
if (ret == -1) {
|
|
if (!rsv_is_empty(&my_rsv->rsv_window))
|
|
rsv_window_remove(sb, my_rsv);
|
|
spin_unlock(rsv_lock);
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* On success, find_next_reservable_window() returns the
|
|
* reservation window where there is a reservable space after it.
|
|
* Before we reserve this reservable space, we need
|
|
* to make sure there is at least a free block inside this region.
|
|
*
|
|
* Search the first free bit on the block bitmap. Search starts from
|
|
* the start block of the reservable space we just found.
|
|
*/
|
|
spin_unlock(rsv_lock);
|
|
first_free_block = bitmap_search_next_usable_block(
|
|
my_rsv->rsv_start - group_first_block,
|
|
bitmap_bh, group_end_block - group_first_block + 1);
|
|
|
|
if (first_free_block < 0) {
|
|
/*
|
|
* no free block left on the bitmap, no point
|
|
* to reserve the space. return failed.
|
|
*/
|
|
spin_lock(rsv_lock);
|
|
if (!rsv_is_empty(&my_rsv->rsv_window))
|
|
rsv_window_remove(sb, my_rsv);
|
|
spin_unlock(rsv_lock);
|
|
return -1; /* failed */
|
|
}
|
|
|
|
start_block = first_free_block + group_first_block;
|
|
/*
|
|
* check if the first free block is within the
|
|
* free space we just reserved
|
|
*/
|
|
if (start_block >= my_rsv->rsv_start && start_block <= my_rsv->rsv_end)
|
|
return 0; /* success */
|
|
/*
|
|
* if the first free bit we found is out of the reservable space
|
|
* continue search for next reservable space,
|
|
* start from where the free block is,
|
|
* we also shift the list head to where we stopped last time
|
|
*/
|
|
search_head = my_rsv;
|
|
spin_lock(rsv_lock);
|
|
goto retry;
|
|
}
|
|
|
|
/**
|
|
* try_to_extend_reservation()
|
|
* @my_rsv: given reservation window
|
|
* @sb: super block
|
|
* @size: the delta to extend
|
|
*
|
|
* Attempt to expand the reservation window large enough to have
|
|
* required number of free blocks
|
|
*
|
|
* Since ext2_try_to_allocate() will always allocate blocks within
|
|
* the reservation window range, if the window size is too small,
|
|
* multiple blocks allocation has to stop at the end of the reservation
|
|
* window. To make this more efficient, given the total number of
|
|
* blocks needed and the current size of the window, we try to
|
|
* expand the reservation window size if necessary on a best-effort
|
|
* basis before ext2_new_blocks() tries to allocate blocks.
|
|
*/
|
|
static void try_to_extend_reservation(struct ext2_reserve_window_node *my_rsv,
|
|
struct super_block *sb, int size)
|
|
{
|
|
struct ext2_reserve_window_node *next_rsv;
|
|
struct rb_node *next;
|
|
spinlock_t *rsv_lock = &EXT2_SB(sb)->s_rsv_window_lock;
|
|
|
|
if (!spin_trylock(rsv_lock))
|
|
return;
|
|
|
|
next = rb_next(&my_rsv->rsv_node);
|
|
|
|
if (!next)
|
|
my_rsv->rsv_end += size;
|
|
else {
|
|
next_rsv = rb_entry(next, struct ext2_reserve_window_node, rsv_node);
|
|
|
|
if ((next_rsv->rsv_start - my_rsv->rsv_end - 1) >= size)
|
|
my_rsv->rsv_end += size;
|
|
else
|
|
my_rsv->rsv_end = next_rsv->rsv_start - 1;
|
|
}
|
|
spin_unlock(rsv_lock);
|
|
}
|
|
|
|
/**
|
|
* ext2_try_to_allocate_with_rsv()
|
|
* @sb: superblock
|
|
* @group: given allocation block group
|
|
* @bitmap_bh: bufferhead holds the block bitmap
|
|
* @grp_goal: given target block within the group
|
|
* @count: target number of blocks to allocate
|
|
* @my_rsv: reservation window
|
|
*
|
|
* This is the main function used to allocate a new block and its reservation
|
|
* window.
|
|
*
|
|
* Each time when a new block allocation is need, first try to allocate from
|
|
* its own reservation. If it does not have a reservation window, instead of
|
|
* looking for a free bit on bitmap first, then look up the reservation list to
|
|
* see if it is inside somebody else's reservation window, we try to allocate a
|
|
* reservation window for it starting from the goal first. Then do the block
|
|
* allocation within the reservation window.
|
|
*
|
|
* This will avoid keeping on searching the reservation list again and
|
|
* again when somebody is looking for a free block (without
|
|
* reservation), and there are lots of free blocks, but they are all
|
|
* being reserved.
|
|
*
|
|
* We use a red-black tree for the per-filesystem reservation list.
|
|
*/
|
|
static ext2_grpblk_t
|
|
ext2_try_to_allocate_with_rsv(struct super_block *sb, unsigned int group,
|
|
struct buffer_head *bitmap_bh, ext2_grpblk_t grp_goal,
|
|
struct ext2_reserve_window_node * my_rsv,
|
|
unsigned long *count)
|
|
{
|
|
ext2_fsblk_t group_first_block, group_last_block;
|
|
ext2_grpblk_t ret = 0;
|
|
unsigned long num = *count;
|
|
|
|
/*
|
|
* we don't deal with reservation when
|
|
* filesystem is mounted without reservation
|
|
* or the file is not a regular file
|
|
* or last attempt to allocate a block with reservation turned on failed
|
|
*/
|
|
if (my_rsv == NULL) {
|
|
return ext2_try_to_allocate(sb, group, bitmap_bh,
|
|
grp_goal, count, NULL);
|
|
}
|
|
/*
|
|
* grp_goal is a group relative block number (if there is a goal)
|
|
* 0 <= grp_goal < EXT2_BLOCKS_PER_GROUP(sb)
|
|
* first block is a filesystem wide block number
|
|
* first block is the block number of the first block in this group
|
|
*/
|
|
group_first_block = ext2_group_first_block_no(sb, group);
|
|
group_last_block = ext2_group_last_block_no(sb, group);
|
|
|
|
/*
|
|
* Basically we will allocate a new block from inode's reservation
|
|
* window.
|
|
*
|
|
* We need to allocate a new reservation window, if:
|
|
* a) inode does not have a reservation window; or
|
|
* b) last attempt to allocate a block from existing reservation
|
|
* failed; or
|
|
* c) we come here with a goal and with a reservation window
|
|
*
|
|
* We do not need to allocate a new reservation window if we come here
|
|
* at the beginning with a goal and the goal is inside the window, or
|
|
* we don't have a goal but already have a reservation window.
|
|
* then we could go to allocate from the reservation window directly.
|
|
*/
|
|
while (1) {
|
|
if (rsv_is_empty(&my_rsv->rsv_window) || (ret < 0) ||
|
|
!goal_in_my_reservation(&my_rsv->rsv_window,
|
|
grp_goal, group, sb)) {
|
|
if (my_rsv->rsv_goal_size < *count)
|
|
my_rsv->rsv_goal_size = *count;
|
|
ret = alloc_new_reservation(my_rsv, grp_goal, sb,
|
|
group, bitmap_bh);
|
|
if (ret < 0)
|
|
break; /* failed */
|
|
|
|
if (!goal_in_my_reservation(&my_rsv->rsv_window,
|
|
grp_goal, group, sb))
|
|
grp_goal = -1;
|
|
} else if (grp_goal >= 0) {
|
|
int curr = my_rsv->rsv_end -
|
|
(grp_goal + group_first_block) + 1;
|
|
|
|
if (curr < *count)
|
|
try_to_extend_reservation(my_rsv, sb,
|
|
*count - curr);
|
|
}
|
|
|
|
if ((my_rsv->rsv_start > group_last_block) ||
|
|
(my_rsv->rsv_end < group_first_block)) {
|
|
rsv_window_dump(&EXT2_SB(sb)->s_rsv_window_root, 1);
|
|
BUG();
|
|
}
|
|
ret = ext2_try_to_allocate(sb, group, bitmap_bh, grp_goal,
|
|
&num, &my_rsv->rsv_window);
|
|
if (ret >= 0) {
|
|
my_rsv->rsv_alloc_hit += num;
|
|
*count = num;
|
|
break; /* succeed */
|
|
}
|
|
num = *count;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* ext2_has_free_blocks()
|
|
* @sbi: in-core super block structure.
|
|
*
|
|
* Check if filesystem has at least 1 free block available for allocation.
|
|
*/
|
|
static int ext2_has_free_blocks(struct ext2_sb_info *sbi)
|
|
{
|
|
ext2_fsblk_t free_blocks, root_blocks;
|
|
|
|
free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
|
|
root_blocks = le32_to_cpu(sbi->s_es->s_r_blocks_count);
|
|
if (free_blocks < root_blocks + 1 && !capable(CAP_SYS_RESOURCE) &&
|
|
!uid_eq(sbi->s_resuid, current_fsuid()) &&
|
|
(gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) ||
|
|
!in_group_p (sbi->s_resgid))) {
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Returns 1 if the passed-in block region is valid; 0 if some part overlaps
|
|
* with filesystem metadata blocks.
|
|
*/
|
|
int ext2_data_block_valid(struct ext2_sb_info *sbi, ext2_fsblk_t start_blk,
|
|
unsigned int count)
|
|
{
|
|
if ((start_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
|
|
(start_blk + count - 1 < start_blk) ||
|
|
(start_blk + count - 1 >= le32_to_cpu(sbi->s_es->s_blocks_count)))
|
|
return 0;
|
|
|
|
/* Ensure we do not step over superblock */
|
|
if ((start_blk <= sbi->s_sb_block) &&
|
|
(start_blk + count - 1 >= sbi->s_sb_block))
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* ext2_new_blocks() -- core block(s) allocation function
|
|
* @inode: file inode
|
|
* @goal: given target block(filesystem wide)
|
|
* @count: target number of blocks to allocate
|
|
* @errp: error code
|
|
*
|
|
* ext2_new_blocks uses a goal block to assist allocation. If the goal is
|
|
* free, or there is a free block within 32 blocks of the goal, that block
|
|
* is allocated. Otherwise a forward search is made for a free block; within
|
|
* each block group the search first looks for an entire free byte in the block
|
|
* bitmap, and then for any free bit if that fails.
|
|
* This function also updates quota and i_blocks field.
|
|
*/
|
|
ext2_fsblk_t ext2_new_blocks(struct inode *inode, ext2_fsblk_t goal,
|
|
unsigned long *count, int *errp)
|
|
{
|
|
struct buffer_head *bitmap_bh = NULL;
|
|
struct buffer_head *gdp_bh;
|
|
int group_no;
|
|
int goal_group;
|
|
ext2_grpblk_t grp_target_blk; /* blockgroup relative goal block */
|
|
ext2_grpblk_t grp_alloc_blk; /* blockgroup-relative allocated block*/
|
|
ext2_fsblk_t ret_block; /* filesyetem-wide allocated block */
|
|
int bgi; /* blockgroup iteration index */
|
|
int performed_allocation = 0;
|
|
ext2_grpblk_t free_blocks; /* number of free blocks in a group */
|
|
struct super_block *sb;
|
|
struct ext2_group_desc *gdp;
|
|
struct ext2_super_block *es;
|
|
struct ext2_sb_info *sbi;
|
|
struct ext2_reserve_window_node *my_rsv = NULL;
|
|
struct ext2_block_alloc_info *block_i;
|
|
unsigned short windowsz = 0;
|
|
unsigned long ngroups;
|
|
unsigned long num = *count;
|
|
int ret;
|
|
|
|
*errp = -ENOSPC;
|
|
sb = inode->i_sb;
|
|
|
|
/*
|
|
* Check quota for allocation of this block.
|
|
*/
|
|
ret = dquot_alloc_block(inode, num);
|
|
if (ret) {
|
|
*errp = ret;
|
|
return 0;
|
|
}
|
|
|
|
sbi = EXT2_SB(sb);
|
|
es = EXT2_SB(sb)->s_es;
|
|
ext2_debug("goal=%lu.\n", goal);
|
|
/*
|
|
* Allocate a block from reservation only when
|
|
* filesystem is mounted with reservation(default,-o reservation), and
|
|
* it's a regular file, and
|
|
* the desired window size is greater than 0 (One could use ioctl
|
|
* command EXT2_IOC_SETRSVSZ to set the window size to 0 to turn off
|
|
* reservation on that particular file)
|
|
*/
|
|
block_i = EXT2_I(inode)->i_block_alloc_info;
|
|
if (block_i) {
|
|
windowsz = block_i->rsv_window_node.rsv_goal_size;
|
|
if (windowsz > 0)
|
|
my_rsv = &block_i->rsv_window_node;
|
|
}
|
|
|
|
if (!ext2_has_free_blocks(sbi)) {
|
|
*errp = -ENOSPC;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* First, test whether the goal block is free.
|
|
*/
|
|
if (goal < le32_to_cpu(es->s_first_data_block) ||
|
|
goal >= le32_to_cpu(es->s_blocks_count))
|
|
goal = le32_to_cpu(es->s_first_data_block);
|
|
group_no = (goal - le32_to_cpu(es->s_first_data_block)) /
|
|
EXT2_BLOCKS_PER_GROUP(sb);
|
|
goal_group = group_no;
|
|
retry_alloc:
|
|
gdp = ext2_get_group_desc(sb, group_no, &gdp_bh);
|
|
if (!gdp)
|
|
goto io_error;
|
|
|
|
free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
|
|
/*
|
|
* if there is not enough free blocks to make a new resevation
|
|
* turn off reservation for this allocation
|
|
*/
|
|
if (my_rsv && (free_blocks < windowsz)
|
|
&& (free_blocks > 0)
|
|
&& (rsv_is_empty(&my_rsv->rsv_window)))
|
|
my_rsv = NULL;
|
|
|
|
if (free_blocks > 0) {
|
|
grp_target_blk = ((goal - le32_to_cpu(es->s_first_data_block)) %
|
|
EXT2_BLOCKS_PER_GROUP(sb));
|
|
/*
|
|
* In case we retry allocation (due to fs reservation not
|
|
* working out or fs corruption), the bitmap_bh is non-null
|
|
* pointer and we have to release it before calling
|
|
* read_block_bitmap().
|
|
*/
|
|
brelse(bitmap_bh);
|
|
bitmap_bh = read_block_bitmap(sb, group_no);
|
|
if (!bitmap_bh)
|
|
goto io_error;
|
|
grp_alloc_blk = ext2_try_to_allocate_with_rsv(sb, group_no,
|
|
bitmap_bh, grp_target_blk,
|
|
my_rsv, &num);
|
|
if (grp_alloc_blk >= 0)
|
|
goto allocated;
|
|
}
|
|
|
|
ngroups = EXT2_SB(sb)->s_groups_count;
|
|
smp_rmb();
|
|
|
|
/*
|
|
* Now search the rest of the groups. We assume that
|
|
* group_no and gdp correctly point to the last group visited.
|
|
*/
|
|
for (bgi = 0; bgi < ngroups; bgi++) {
|
|
group_no++;
|
|
if (group_no >= ngroups)
|
|
group_no = 0;
|
|
gdp = ext2_get_group_desc(sb, group_no, &gdp_bh);
|
|
if (!gdp)
|
|
goto io_error;
|
|
|
|
free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
|
|
/*
|
|
* skip this group (and avoid loading bitmap) if there
|
|
* are no free blocks
|
|
*/
|
|
if (!free_blocks)
|
|
continue;
|
|
/*
|
|
* skip this group if the number of
|
|
* free blocks is less than half of the reservation
|
|
* window size.
|
|
*/
|
|
if (my_rsv && (free_blocks <= (windowsz/2)))
|
|
continue;
|
|
|
|
brelse(bitmap_bh);
|
|
bitmap_bh = read_block_bitmap(sb, group_no);
|
|
if (!bitmap_bh)
|
|
goto io_error;
|
|
/*
|
|
* try to allocate block(s) from this group, without a goal(-1).
|
|
*/
|
|
grp_alloc_blk = ext2_try_to_allocate_with_rsv(sb, group_no,
|
|
bitmap_bh, -1, my_rsv, &num);
|
|
if (grp_alloc_blk >= 0)
|
|
goto allocated;
|
|
}
|
|
/*
|
|
* We may end up a bogus earlier ENOSPC error due to
|
|
* filesystem is "full" of reservations, but
|
|
* there maybe indeed free blocks available on disk
|
|
* In this case, we just forget about the reservations
|
|
* just do block allocation as without reservations.
|
|
*/
|
|
if (my_rsv) {
|
|
my_rsv = NULL;
|
|
windowsz = 0;
|
|
group_no = goal_group;
|
|
goto retry_alloc;
|
|
}
|
|
/* No space left on the device */
|
|
*errp = -ENOSPC;
|
|
goto out;
|
|
|
|
allocated:
|
|
|
|
ext2_debug("using block group %d(%d)\n",
|
|
group_no, gdp->bg_free_blocks_count);
|
|
|
|
ret_block = grp_alloc_blk + ext2_group_first_block_no(sb, group_no);
|
|
|
|
if (in_range(le32_to_cpu(gdp->bg_block_bitmap), ret_block, num) ||
|
|
in_range(le32_to_cpu(gdp->bg_inode_bitmap), ret_block, num) ||
|
|
in_range(ret_block, le32_to_cpu(gdp->bg_inode_table),
|
|
EXT2_SB(sb)->s_itb_per_group) ||
|
|
in_range(ret_block + num - 1, le32_to_cpu(gdp->bg_inode_table),
|
|
EXT2_SB(sb)->s_itb_per_group)) {
|
|
ext2_error(sb, "ext2_new_blocks",
|
|
"Allocating block in system zone - "
|
|
"blocks from "E2FSBLK", length %lu",
|
|
ret_block, num);
|
|
/*
|
|
* ext2_try_to_allocate marked the blocks we allocated as in
|
|
* use. So we may want to selectively mark some of the blocks
|
|
* as free
|
|
*/
|
|
num = *count;
|
|
goto retry_alloc;
|
|
}
|
|
|
|
performed_allocation = 1;
|
|
|
|
if (ret_block + num - 1 >= le32_to_cpu(es->s_blocks_count)) {
|
|
ext2_error(sb, "ext2_new_blocks",
|
|
"block("E2FSBLK") >= blocks count(%d) - "
|
|
"block_group = %d, es == %p ", ret_block,
|
|
le32_to_cpu(es->s_blocks_count), group_no, es);
|
|
goto out;
|
|
}
|
|
|
|
group_adjust_blocks(sb, group_no, gdp, gdp_bh, -num);
|
|
percpu_counter_sub(&sbi->s_freeblocks_counter, num);
|
|
|
|
mark_buffer_dirty(bitmap_bh);
|
|
if (sb->s_flags & SB_SYNCHRONOUS)
|
|
sync_dirty_buffer(bitmap_bh);
|
|
|
|
*errp = 0;
|
|
brelse(bitmap_bh);
|
|
if (num < *count) {
|
|
dquot_free_block_nodirty(inode, *count-num);
|
|
mark_inode_dirty(inode);
|
|
*count = num;
|
|
}
|
|
return ret_block;
|
|
|
|
io_error:
|
|
*errp = -EIO;
|
|
out:
|
|
/*
|
|
* Undo the block allocation
|
|
*/
|
|
if (!performed_allocation) {
|
|
dquot_free_block_nodirty(inode, *count);
|
|
mark_inode_dirty(inode);
|
|
}
|
|
brelse(bitmap_bh);
|
|
return 0;
|
|
}
|
|
|
|
ext2_fsblk_t ext2_new_block(struct inode *inode, unsigned long goal, int *errp)
|
|
{
|
|
unsigned long count = 1;
|
|
|
|
return ext2_new_blocks(inode, goal, &count, errp);
|
|
}
|
|
|
|
#ifdef EXT2FS_DEBUG
|
|
|
|
unsigned long ext2_count_free(struct buffer_head *map, unsigned int numchars)
|
|
{
|
|
return numchars * BITS_PER_BYTE - memweight(map->b_data, numchars);
|
|
}
|
|
|
|
#endif /* EXT2FS_DEBUG */
|
|
|
|
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;
|
|
|
|
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);
|
|
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 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)
|
|
{
|
|
return ext2_bg_has_super(sb, group) ? EXT2_SB(sb)->s_gdb_count : 0;
|
|
}
|
|
|