| 1 |
199 |
simons |
/*
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| 2 |
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* linux/fs/ext/freelists.c
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| 3 |
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*
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| 4 |
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* Copyright (C) 1992 Remy Card (card@masi.ibp.fr)
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*
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| 6 |
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*/
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| 7 |
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| 8 |
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/* freelists.c contains the code that handles the inode and block free lists */
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| 11 |
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/*
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| 13 |
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The free blocks are managed by a linked list. The super block contains the
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number of the first free block. This block contains 254 numbers of other
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| 15 |
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free blocks and the number of the next block in the list.
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| 17 |
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When an ext fs is mounted, the number of the first free block is stored
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| 18 |
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in s->u.ext_sb.s_firstfreeblocknumber and the block header is stored in
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| 19 |
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s->u.ext_sb.s_firstfreeblock. u.ext_sb.s_freeblockscount contains the count
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| 20 |
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of free blocks.
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| 22 |
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The free inodes are also managed by a linked list in a similar way. The
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super block contains the number of the first free inode. This inode contains
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| 24 |
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14 numbers of other free inodes and the number of the next inode in the list.
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| 26 |
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The number of the first free inode is stored in
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| 27 |
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s->u.ext_sb.s_firstfreeinodenumber and the header of the block containing
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| 28 |
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the inode is stored in s->u.ext_sb.s_firstfreeinodeblock.
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u.ext_sb.s_freeinodescount contains the count of free inodes.
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| 30 |
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| 31 |
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*/
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| 33 |
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#include <linux/sched.h>
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| 34 |
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#include <linux/ext_fs.h>
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| 35 |
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#include <linux/stat.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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| 38 |
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#include <linux/locks.h>
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| 39 |
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| 40 |
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void ext_free_block(struct super_block * sb, int block)
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| 41 |
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{
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| 42 |
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struct buffer_head * bh;
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| 43 |
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struct ext_free_block * efb;
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| 44 |
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| 45 |
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if (!sb) {
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| 46 |
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printk("trying to free block on non-existent device\n");
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| 47 |
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return;
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| 48 |
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}
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| 49 |
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lock_super (sb);
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| 50 |
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if (block < sb->u.ext_sb.s_firstdatazone ||
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| 51 |
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block >= sb->u.ext_sb.s_nzones) {
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| 52 |
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printk("trying to free block not in datazone\n");
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| 53 |
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return;
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| 54 |
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}
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| 55 |
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bh = get_hash_table(sb->s_dev, block, sb->s_blocksize);
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| 56 |
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if (bh)
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| 57 |
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mark_buffer_clean(bh);
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| 58 |
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brelse(bh);
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| 59 |
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if (sb->u.ext_sb.s_firstfreeblock)
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| 60 |
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efb = (struct ext_free_block *) sb->u.ext_sb.s_firstfreeblock->b_data;
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| 61 |
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if (!sb->u.ext_sb.s_firstfreeblock || efb->count == 254) {
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| 62 |
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#ifdef EXTFS_DEBUG
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| 63 |
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printk("ext_free_block: block full, skipping to %d\n", block);
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| 64 |
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#endif
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| 65 |
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if (sb->u.ext_sb.s_firstfreeblock)
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brelse (sb->u.ext_sb.s_firstfreeblock);
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| 67 |
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if (!(sb->u.ext_sb.s_firstfreeblock = bread (sb->s_dev,
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| 68 |
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block, sb->s_blocksize)))
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| 69 |
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panic ("ext_free_block: unable to read block to free\n");
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| 70 |
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efb = (struct ext_free_block *) sb->u.ext_sb.s_firstfreeblock->b_data;
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| 71 |
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efb->next = sb->u.ext_sb.s_firstfreeblocknumber;
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| 72 |
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efb->count = 0;
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| 73 |
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sb->u.ext_sb.s_firstfreeblocknumber = block;
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} else {
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| 75 |
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efb->free[efb->count++] = block;
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| 76 |
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}
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sb->u.ext_sb.s_freeblockscount ++;
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sb->s_dirt = 1;
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| 79 |
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mark_buffer_dirty(sb->u.ext_sb.s_firstfreeblock, 1);
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| 80 |
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unlock_super (sb);
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return;
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| 82 |
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}
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| 83 |
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| 84 |
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int ext_new_block(struct super_block * sb)
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{
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| 86 |
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struct buffer_head * bh;
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| 87 |
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struct ext_free_block * efb;
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| 88 |
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int j;
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| 89 |
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| 90 |
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if (!sb) {
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| 91 |
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printk("trying to get new block from non-existent device\n");
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| 92 |
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return 0;
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| 93 |
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}
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| 94 |
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if (!sb->u.ext_sb.s_firstfreeblock)
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| 95 |
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return 0;
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lock_super (sb);
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| 97 |
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efb = (struct ext_free_block *) sb->u.ext_sb.s_firstfreeblock->b_data;
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| 98 |
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if (efb->count) {
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| 99 |
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j = efb->free[--efb->count];
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mark_buffer_dirty(sb->u.ext_sb.s_firstfreeblock, 1);
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| 101 |
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} else {
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| 102 |
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#ifdef EXTFS_DEBUG
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printk("ext_new_block: block empty, skipping to %d\n", efb->next);
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| 104 |
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#endif
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| 105 |
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j = sb->u.ext_sb.s_firstfreeblocknumber;
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sb->u.ext_sb.s_firstfreeblocknumber = efb->next;
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| 107 |
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brelse (sb->u.ext_sb.s_firstfreeblock);
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if (!sb->u.ext_sb.s_firstfreeblocknumber) {
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| 109 |
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sb->u.ext_sb.s_firstfreeblock = NULL;
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| 110 |
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} else {
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| 111 |
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if (!(sb->u.ext_sb.s_firstfreeblock = bread (sb->s_dev,
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| 112 |
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sb->u.ext_sb.s_firstfreeblocknumber,
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| 113 |
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sb->s_blocksize)))
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| 114 |
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panic ("ext_new_block: unable to read next free block\n");
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| 115 |
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}
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| 116 |
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}
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| 117 |
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if (j < sb->u.ext_sb.s_firstdatazone || j > sb->u.ext_sb.s_nzones) {
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| 118 |
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printk ("ext_new_block: blk = %d\n", j);
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| 119 |
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printk("allocating block not in data zone\n");
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| 120 |
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return 0;
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| 121 |
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}
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| 122 |
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sb->u.ext_sb.s_freeblockscount --;
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| 123 |
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sb->s_dirt = 1;
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| 124 |
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| 125 |
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if (!(bh=getblk(sb->s_dev, j, sb->s_blocksize))) {
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| 126 |
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printk("new_block: cannot get block");
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| 127 |
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return 0;
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| 128 |
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}
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| 129 |
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memset(bh->b_data, 0, BLOCK_SIZE);
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| 130 |
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mark_buffer_uptodate(bh, 1);
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| 131 |
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mark_buffer_dirty(bh, 1);
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| 132 |
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brelse(bh);
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| 133 |
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#ifdef EXTFS_DEBUG
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| 134 |
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printk("ext_new_block: allocating block %d\n", j);
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| 135 |
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#endif
|
| 136 |
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unlock_super (sb);
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| 137 |
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return j;
|
| 138 |
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}
|
| 139 |
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|
| 140 |
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unsigned long ext_count_free_blocks(struct super_block *sb)
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| 141 |
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{
|
| 142 |
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#ifdef EXTFS_DEBUG
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| 143 |
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struct buffer_head * bh;
|
| 144 |
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struct ext_free_block * efb;
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| 145 |
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unsigned long count, block;
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| 146 |
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| 147 |
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lock_super (sb);
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| 148 |
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if (!sb->u.ext_sb.s_firstfreeblock)
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| 149 |
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count = 0;
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| 150 |
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else {
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| 151 |
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efb = (struct ext_free_block *) sb->u.ext_sb.s_firstfreeblock->b_data;
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| 152 |
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count = efb->count + 1;
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| 153 |
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block = efb->next;
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| 154 |
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while (block) {
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| 155 |
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if (!(bh = bread (sb->s_dev, block, sb->s_blocksize))) {
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| 156 |
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printk ("ext_count_free: error while reading free blocks list\n");
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| 157 |
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block = 0;
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| 158 |
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} else {
|
| 159 |
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efb = (struct ext_free_block *) bh->b_data;
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| 160 |
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count += efb->count + 1;
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| 161 |
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block = efb->next;
|
| 162 |
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brelse (bh);
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| 163 |
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}
|
| 164 |
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}
|
| 165 |
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}
|
| 166 |
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printk("ext_count_free_blocks: stored = %d, computed = %d\n",
|
| 167 |
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sb->u.ext_sb.s_freeblockscount, count);
|
| 168 |
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unlock_super (sb);
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| 169 |
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return count;
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| 170 |
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#else
|
| 171 |
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return sb->u.ext_sb.s_freeblockscount;
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| 172 |
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#endif
|
| 173 |
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}
|
| 174 |
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|
| 175 |
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void ext_free_inode(struct inode * inode)
|
| 176 |
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{
|
| 177 |
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struct buffer_head * bh;
|
| 178 |
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struct ext_free_inode * efi;
|
| 179 |
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struct super_block * sb;
|
| 180 |
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unsigned long block;
|
| 181 |
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unsigned long ino;
|
| 182 |
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kdev_t dev;
|
| 183 |
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|
| 184 |
|
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if (!inode)
|
| 185 |
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return;
|
| 186 |
|
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if (!inode->i_dev) {
|
| 187 |
|
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printk("free_inode: inode has no device\n");
|
| 188 |
|
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return;
|
| 189 |
|
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}
|
| 190 |
|
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if (inode->i_count != 1) {
|
| 191 |
|
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printk("free_inode: inode has count=%ld\n",inode->i_count);
|
| 192 |
|
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return;
|
| 193 |
|
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}
|
| 194 |
|
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if (inode->i_nlink) {
|
| 195 |
|
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printk("free_inode: inode has nlink=%d\n",inode->i_nlink);
|
| 196 |
|
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return;
|
| 197 |
|
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}
|
| 198 |
|
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if (!inode->i_sb) {
|
| 199 |
|
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printk("free_inode: inode on non-existent device\n");
|
| 200 |
|
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return;
|
| 201 |
|
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}
|
| 202 |
|
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sb = inode->i_sb;
|
| 203 |
|
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ino = inode->i_ino;
|
| 204 |
|
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dev = inode->i_dev;
|
| 205 |
|
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clear_inode(inode);
|
| 206 |
|
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lock_super (sb);
|
| 207 |
|
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if (ino < 1 || ino > sb->u.ext_sb.s_ninodes) {
|
| 208 |
|
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printk("free_inode: inode 0 or non-existent inode\n");
|
| 209 |
|
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unlock_super (sb);
|
| 210 |
|
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return;
|
| 211 |
|
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}
|
| 212 |
|
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if (sb->u.ext_sb.s_firstfreeinodeblock)
|
| 213 |
|
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efi = ((struct ext_free_inode *) sb->u.ext_sb.s_firstfreeinodeblock->b_data) +
|
| 214 |
|
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(sb->u.ext_sb.s_firstfreeinodenumber-1)%EXT_INODES_PER_BLOCK;
|
| 215 |
|
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if (!sb->u.ext_sb.s_firstfreeinodeblock || efi->count == 14) {
|
| 216 |
|
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#ifdef EXTFS_DEBUG
|
| 217 |
|
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printk("ext_free_inode: inode full, skipping to %d\n", ino);
|
| 218 |
|
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#endif
|
| 219 |
|
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if (sb->u.ext_sb.s_firstfreeinodeblock)
|
| 220 |
|
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brelse (sb->u.ext_sb.s_firstfreeinodeblock);
|
| 221 |
|
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block = 2 + (ino - 1) / EXT_INODES_PER_BLOCK;
|
| 222 |
|
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if (!(bh = bread(dev, block, sb->s_blocksize)))
|
| 223 |
|
|
panic("ext_free_inode: unable to read inode block\n");
|
| 224 |
|
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efi = ((struct ext_free_inode *) bh->b_data) +
|
| 225 |
|
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(ino - 1) % EXT_INODES_PER_BLOCK;
|
| 226 |
|
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efi->next = sb->u.ext_sb.s_firstfreeinodenumber;
|
| 227 |
|
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efi->count = 0;
|
| 228 |
|
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sb->u.ext_sb.s_firstfreeinodenumber = ino;
|
| 229 |
|
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sb->u.ext_sb.s_firstfreeinodeblock = bh;
|
| 230 |
|
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} else {
|
| 231 |
|
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efi->free[efi->count++] = ino;
|
| 232 |
|
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}
|
| 233 |
|
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sb->u.ext_sb.s_freeinodescount ++;
|
| 234 |
|
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sb->s_dirt = 1;
|
| 235 |
|
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mark_buffer_dirty(sb->u.ext_sb.s_firstfreeinodeblock, 1);
|
| 236 |
|
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unlock_super (sb);
|
| 237 |
|
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}
|
| 238 |
|
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|
| 239 |
|
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struct inode * ext_new_inode(const struct inode * dir)
|
| 240 |
|
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{
|
| 241 |
|
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struct super_block * sb;
|
| 242 |
|
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struct inode * inode;
|
| 243 |
|
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struct ext_free_inode * efi;
|
| 244 |
|
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unsigned long block;
|
| 245 |
|
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int j;
|
| 246 |
|
|
|
| 247 |
|
|
if (!dir || !(inode=get_empty_inode()))
|
| 248 |
|
|
return NULL;
|
| 249 |
|
|
sb = dir->i_sb;
|
| 250 |
|
|
inode->i_sb = sb;
|
| 251 |
|
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inode->i_flags = sb->s_flags;
|
| 252 |
|
|
if (!sb->u.ext_sb.s_firstfreeinodeblock)
|
| 253 |
|
|
return 0;
|
| 254 |
|
|
lock_super (sb);
|
| 255 |
|
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efi = ((struct ext_free_inode *) sb->u.ext_sb.s_firstfreeinodeblock->b_data) +
|
| 256 |
|
|
(sb->u.ext_sb.s_firstfreeinodenumber-1)%EXT_INODES_PER_BLOCK;
|
| 257 |
|
|
if (efi->count) {
|
| 258 |
|
|
j = efi->free[--efi->count];
|
| 259 |
|
|
mark_buffer_dirty(sb->u.ext_sb.s_firstfreeinodeblock, 1);
|
| 260 |
|
|
} else {
|
| 261 |
|
|
#ifdef EXTFS_DEBUG
|
| 262 |
|
|
printk("ext_free_inode: inode empty, skipping to %d\n", efi->next);
|
| 263 |
|
|
#endif
|
| 264 |
|
|
j = sb->u.ext_sb.s_firstfreeinodenumber;
|
| 265 |
|
|
if (efi->next > sb->u.ext_sb.s_ninodes) {
|
| 266 |
|
|
printk ("efi->next = %ld\n", efi->next);
|
| 267 |
|
|
panic ("ext_new_inode: bad inode number in free list\n");
|
| 268 |
|
|
}
|
| 269 |
|
|
sb->u.ext_sb.s_firstfreeinodenumber = efi->next;
|
| 270 |
|
|
block = 2 + (((unsigned long) efi->next) - 1) / EXT_INODES_PER_BLOCK;
|
| 271 |
|
|
brelse (sb->u.ext_sb.s_firstfreeinodeblock);
|
| 272 |
|
|
if (!sb->u.ext_sb.s_firstfreeinodenumber) {
|
| 273 |
|
|
sb->u.ext_sb.s_firstfreeinodeblock = NULL;
|
| 274 |
|
|
} else {
|
| 275 |
|
|
if (!(sb->u.ext_sb.s_firstfreeinodeblock =
|
| 276 |
|
|
bread(sb->s_dev, block, sb->s_blocksize)))
|
| 277 |
|
|
panic ("ext_new_inode: unable to read next free inode block\n");
|
| 278 |
|
|
}
|
| 279 |
|
|
}
|
| 280 |
|
|
sb->u.ext_sb.s_freeinodescount --;
|
| 281 |
|
|
sb->s_dirt = 1;
|
| 282 |
|
|
inode->i_count = 1;
|
| 283 |
|
|
inode->i_nlink = 1;
|
| 284 |
|
|
inode->i_dev = sb->s_dev;
|
| 285 |
|
|
inode->i_uid = current->fsuid;
|
| 286 |
|
|
inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid;
|
| 287 |
|
|
inode->i_dirt = 1;
|
| 288 |
|
|
inode->i_ino = j;
|
| 289 |
|
|
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
|
| 290 |
|
|
inode->i_op = NULL;
|
| 291 |
|
|
inode->i_blocks = inode->i_blksize = 0;
|
| 292 |
|
|
insert_inode_hash(inode);
|
| 293 |
|
|
#ifdef EXTFS_DEBUG
|
| 294 |
|
|
printk("ext_new_inode : allocating inode %d\n", inode->i_ino);
|
| 295 |
|
|
#endif
|
| 296 |
|
|
unlock_super (sb);
|
| 297 |
|
|
return inode;
|
| 298 |
|
|
}
|
| 299 |
|
|
|
| 300 |
|
|
unsigned long ext_count_free_inodes(struct super_block *sb)
|
| 301 |
|
|
{
|
| 302 |
|
|
#ifdef EXTFS_DEBUG
|
| 303 |
|
|
struct buffer_head * bh;
|
| 304 |
|
|
struct ext_free_inode * efi;
|
| 305 |
|
|
unsigned long count, block, ino;
|
| 306 |
|
|
|
| 307 |
|
|
lock_super (sb);
|
| 308 |
|
|
if (!sb->u.ext_sb.s_firstfreeinodeblock)
|
| 309 |
|
|
count = 0;
|
| 310 |
|
|
else {
|
| 311 |
|
|
efi = ((struct ext_free_inode *) sb->u.ext_sb.s_firstfreeinodeblock->b_data) +
|
| 312 |
|
|
((sb->u.ext_sb.s_firstfreeinodenumber-1)%EXT_INODES_PER_BLOCK);
|
| 313 |
|
|
count = efi->count + 1;
|
| 314 |
|
|
ino = efi->next;
|
| 315 |
|
|
while (ino) {
|
| 316 |
|
|
if (ino < 1 || ino > sb->u.ext_sb.s_ninodes) {
|
| 317 |
|
|
printk ("u.ext_sb.s_firstfreeinodenumber = %d, ino = %d\n",
|
| 318 |
|
|
(int) sb->u.ext_sb.s_firstfreeinodenumber,ino);
|
| 319 |
|
|
panic ("ext_count_fre_inodes: bad inode number in free list\n");
|
| 320 |
|
|
}
|
| 321 |
|
|
block = 2 + ((ino - 1) / EXT_INODES_PER_BLOCK);
|
| 322 |
|
|
if (!(bh = bread (sb->s_dev, block, sb->s_blocksize))) {
|
| 323 |
|
|
printk ("ext_count_free_inodes: error while reading free inodes list\n");
|
| 324 |
|
|
block = 0;
|
| 325 |
|
|
} else {
|
| 326 |
|
|
efi = ((struct ext_free_inode *) bh->b_data) +
|
| 327 |
|
|
((ino - 1) % EXT_INODES_PER_BLOCK);
|
| 328 |
|
|
count += efi->count + 1;
|
| 329 |
|
|
ino = efi->next;
|
| 330 |
|
|
brelse (bh);
|
| 331 |
|
|
}
|
| 332 |
|
|
}
|
| 333 |
|
|
}
|
| 334 |
|
|
printk("ext_count_free_inodes: stored = %d, computed = %d\n",
|
| 335 |
|
|
sb->u.ext_sb.s_freeinodescount, count);
|
| 336 |
|
|
unlock_super (sb);
|
| 337 |
|
|
return count;
|
| 338 |
|
|
#else
|
| 339 |
|
|
return sb->u.ext_sb.s_freeinodescount;
|
| 340 |
|
|
#endif
|
| 341 |
|
|
}
|
