3c6441a736
code has the typical branch prediction detour, which creates cross- section branches. A LINT kernel is apparently large enough nowadays that the .text and .text2 sections cannot always be layed-out so that branches between them reach. The fix is to stop using the alpha-specific bitops and instead use the portable implementation used by all platforms other than alpha and i386.
513 lines
14 KiB
C
513 lines
14 KiB
C
/*
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* modified for Lites 1.1
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*
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* Aug 1995, Godmar Back (gback@cs.utah.edu)
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* University of Utah, Department of Computer Science
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*
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* $FreeBSD$
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*/
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/*
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* linux/fs/ext2/ialloc.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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* BSD ufs-inspired inode and directory allocation by
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* Stephen Tweedie (sct@dcs.ed.ac.uk), 1993
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*/
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/*
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* The free inodes are managed by bitmaps. A file system contains several
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* blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
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* block for inodes, N blocks for the inode table and data blocks.
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*
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* The file system contains group descriptors which are located after the
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* super block. Each descriptor contains the number of the bitmap block and
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* the free blocks count in the block. The descriptors are loaded in memory
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* when a file system is mounted (see ext2_read_super).
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/bio.h>
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#include <sys/buf.h>
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#include <sys/mount.h>
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#include <sys/vnode.h>
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#include <gnu/ext2fs/inode.h>
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#include <gnu/ext2fs/ext2_mount.h>
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#include <gnu/ext2fs/ext2_extern.h>
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#include <gnu/ext2fs/ext2_fs.h>
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#include <gnu/ext2fs/ext2_fs_sb.h>
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#include <gnu/ext2fs/fs.h>
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#include <sys/stat.h>
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#ifdef __i386__
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#include <gnu/ext2fs/i386-bitops.h>
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#else
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#include <gnu/ext2fs/ext2_bitops.h>
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#endif
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/* this is supposed to mark a buffer dirty on ready for delayed writing
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*/
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void mark_buffer_dirty(struct buf *bh)
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{
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int s;
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s = splbio();
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bh->b_flags |= B_DIRTY;
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splx(s);
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}
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struct ext2_group_desc * get_group_desc (struct mount * mp,
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unsigned int block_group,
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struct buffer_head ** bh)
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{
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struct ext2_sb_info *sb = VFSTOEXT2(mp)->um_e2fs;
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unsigned long group_desc;
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unsigned long desc;
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struct ext2_group_desc * gdp;
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if (block_group >= sb->s_groups_count)
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panic ("get_group_desc: "
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"block_group >= groups_count - "
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"block_group = %d, groups_count = %lu",
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block_group, sb->s_groups_count);
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group_desc = block_group / EXT2_DESC_PER_BLOCK(sb);
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desc = block_group % EXT2_DESC_PER_BLOCK(sb);
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if (!sb->s_group_desc[group_desc])
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panic ( "get_group_desc:"
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"Group descriptor not loaded - "
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"block_group = %d, group_desc = %lu, desc = %lu",
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block_group, group_desc, desc);
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gdp = (struct ext2_group_desc *)
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sb->s_group_desc[group_desc]->b_data;
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if (bh)
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*bh = sb->s_group_desc[group_desc];
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return gdp + desc;
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}
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static void read_inode_bitmap (struct mount * mp,
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unsigned long block_group,
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unsigned int bitmap_nr)
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{
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struct ext2_sb_info *sb = VFSTOEXT2(mp)->um_e2fs;
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struct ext2_group_desc * gdp;
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struct buffer_head * bh;
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int error;
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gdp = get_group_desc (mp, block_group, NULL);
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if ((error = bread (VFSTOEXT2(mp)->um_devvp,
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fsbtodb(sb, gdp->bg_inode_bitmap),
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sb->s_blocksize,
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NOCRED, &bh)) != 0)
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panic ( "read_inode_bitmap:"
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"Cannot read inode bitmap - "
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"block_group = %lu, inode_bitmap = %lu",
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block_group, (unsigned long) gdp->bg_inode_bitmap);
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sb->s_inode_bitmap_number[bitmap_nr] = block_group;
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sb->s_inode_bitmap[bitmap_nr] = bh;
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LCK_BUF(bh)
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}
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/*
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* load_inode_bitmap loads the inode bitmap for a blocks group
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*
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* It maintains a cache for the last bitmaps loaded. This cache is managed
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* with a LRU algorithm.
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*
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* Notes:
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* 1/ There is one cache per mounted file system.
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* 2/ If the file system contains less than EXT2_MAX_GROUP_LOADED groups,
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* this function reads the bitmap without maintaining a LRU cache.
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*/
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static int load_inode_bitmap (struct mount * mp,
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unsigned int block_group)
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{
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struct ext2_sb_info *sb = VFSTOEXT2(mp)->um_e2fs;
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int i, j;
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unsigned long inode_bitmap_number;
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struct buffer_head * inode_bitmap;
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if (block_group >= sb->s_groups_count)
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panic ("load_inode_bitmap:"
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"block_group >= groups_count - "
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"block_group = %d, groups_count = %lu",
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block_group, sb->s_groups_count);
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if (sb->s_loaded_inode_bitmaps > 0 &&
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sb->s_inode_bitmap_number[0] == block_group)
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return 0;
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if (sb->s_groups_count <= EXT2_MAX_GROUP_LOADED) {
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if (sb->s_inode_bitmap[block_group]) {
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if (sb->s_inode_bitmap_number[block_group] !=
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block_group)
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panic ( "load_inode_bitmap:"
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"block_group != inode_bitmap_number");
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else
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return block_group;
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} else {
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read_inode_bitmap (mp, block_group, block_group);
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return block_group;
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}
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}
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for (i = 0; i < sb->s_loaded_inode_bitmaps &&
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sb->s_inode_bitmap_number[i] != block_group;
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i++)
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;
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if (i < sb->s_loaded_inode_bitmaps &&
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sb->s_inode_bitmap_number[i] == block_group) {
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inode_bitmap_number = sb->s_inode_bitmap_number[i];
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inode_bitmap = sb->s_inode_bitmap[i];
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for (j = i; j > 0; j--) {
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sb->s_inode_bitmap_number[j] =
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sb->s_inode_bitmap_number[j - 1];
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sb->s_inode_bitmap[j] =
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sb->s_inode_bitmap[j - 1];
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}
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sb->s_inode_bitmap_number[0] = inode_bitmap_number;
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sb->s_inode_bitmap[0] = inode_bitmap;
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} else {
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if (sb->s_loaded_inode_bitmaps < EXT2_MAX_GROUP_LOADED)
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sb->s_loaded_inode_bitmaps++;
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else
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ULCK_BUF(sb->s_inode_bitmap[EXT2_MAX_GROUP_LOADED - 1])
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for (j = sb->s_loaded_inode_bitmaps - 1; j > 0; j--) {
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sb->s_inode_bitmap_number[j] =
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sb->s_inode_bitmap_number[j - 1];
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sb->s_inode_bitmap[j] =
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sb->s_inode_bitmap[j - 1];
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}
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read_inode_bitmap (mp, block_group, 0);
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}
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return 0;
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}
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void ext2_free_inode (struct inode * inode)
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{
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struct ext2_sb_info * sb;
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struct buffer_head * bh;
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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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int bitmap_nr;
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struct ext2_group_desc * gdp;
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struct ext2_super_block * es;
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if (!inode)
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return;
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if (inode->i_nlink) {
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printf ("ext2_free_inode: inode has nlink=%d\n",
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inode->i_nlink);
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return;
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}
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ext2_debug ("freeing inode %lu\n", inode->i_number);
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sb = inode->i_e2fs;
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lock_super (DEVVP(inode));
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if (inode->i_number < EXT2_FIRST_INO ||
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inode->i_number > sb->s_es->s_inodes_count) {
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printf ("free_inode reserved inode or nonexistent inode");
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unlock_super (DEVVP(inode));
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return;
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}
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es = sb->s_es;
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block_group = (inode->i_number - 1) / EXT2_INODES_PER_GROUP(sb);
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bit = (inode->i_number - 1) % EXT2_INODES_PER_GROUP(sb);
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bitmap_nr = load_inode_bitmap (ITOV(inode)->v_mount, block_group);
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bh = sb->s_inode_bitmap[bitmap_nr];
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if (!clear_bit (bit, bh->b_data))
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printf ( "ext2_free_inode:"
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"bit already cleared for inode %lu",
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(unsigned long)inode->i_number);
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else {
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gdp = get_group_desc (ITOV(inode)->v_mount, block_group, &bh2);
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gdp->bg_free_inodes_count++;
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if (S_ISDIR(inode->i_mode))
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gdp->bg_used_dirs_count--;
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mark_buffer_dirty(bh2);
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es->s_free_inodes_count++;
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}
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mark_buffer_dirty(bh);
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/*** XXX
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if (sb->s_flags & MS_SYNCHRONOUS) {
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ll_rw_block (WRITE, 1, &bh);
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wait_on_buffer (bh);
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}
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***/
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sb->s_dirt = 1;
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unlock_super (DEVVP(inode));
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}
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#if linux
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/*
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* This function increments the inode version number
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*
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* This may be used one day by the NFS server
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*/
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static void inc_inode_version (struct inode * inode,
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struct ext2_group_desc *gdp,
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int mode)
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{
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unsigned long inode_block;
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struct buffer_head * bh;
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struct ext2_inode * raw_inode;
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inode_block = gdp->bg_inode_table + (((inode->i_number - 1) %
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EXT2_INODES_PER_GROUP(inode->i_sb)) /
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EXT2_INODES_PER_BLOCK(inode->i_sb));
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bh = bread (inode->i_sb->s_dev, inode_block, inode->i_sb->s_blocksize);
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if (!bh) {
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printf ("inc_inode_version Cannot load inode table block - "
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"inode=%lu, inode_block=%lu\n",
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inode->i_number, inode_block);
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inode->u.ext2_i.i_version = 1;
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return;
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}
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raw_inode = ((struct ext2_inode *) bh->b_data) +
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(((inode->i_number - 1) %
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EXT2_INODES_PER_GROUP(inode->i_sb)) %
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EXT2_INODES_PER_BLOCK(inode->i_sb));
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raw_inode->i_version++;
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inode->u.ext2_i.i_version = raw_inode->i_version;
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bdwrite (bh);
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}
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#endif /* linux */
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/*
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* There are two policies for allocating an inode. If the new inode is
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* a directory, then a forward search is made for a block group with both
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* free space and a low directory-to-inode ratio; if that fails, then of
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* the groups with above-average free space, that group with the fewest
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* directories already is chosen.
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*
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* For other inodes, search forward from the parent directory\'s block
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* group to find a free inode.
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*/
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/*
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* this functino has been reduced to the actual 'find the inode number' part
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*/
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ino_t ext2_new_inode (const struct inode * dir, int mode)
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{
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struct ext2_sb_info * sb;
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struct buffer_head * bh;
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struct buffer_head * bh2;
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int i, j, avefreei;
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int bitmap_nr;
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struct ext2_group_desc * gdp;
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struct ext2_group_desc * tmp;
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struct ext2_super_block * es;
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if (!dir)
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return 0;
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sb = dir->i_e2fs;
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lock_super (DEVVP(dir));
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es = sb->s_es;
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repeat:
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gdp = NULL; i=0;
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if (S_ISDIR(mode)) {
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avefreei = es->s_free_inodes_count /
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sb->s_groups_count;
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/* I am not yet convinced that this next bit is necessary.
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i = dir->u.ext2_i.i_block_group;
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for (j = 0; j < sb->u.ext2_sb.s_groups_count; j++) {
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tmp = get_group_desc (sb, i, &bh2);
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if ((tmp->bg_used_dirs_count << 8) <
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tmp->bg_free_inodes_count) {
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gdp = tmp;
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break;
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}
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else
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i = ++i % sb->u.ext2_sb.s_groups_count;
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}
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*/
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if (!gdp) {
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for (j = 0; j < sb->s_groups_count; j++) {
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tmp = get_group_desc(ITOV(dir)->v_mount,j,&bh2);
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if (tmp->bg_free_inodes_count &&
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tmp->bg_free_inodes_count >= avefreei) {
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if (!gdp ||
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(tmp->bg_free_blocks_count >
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gdp->bg_free_blocks_count)) {
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i = j;
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gdp = tmp;
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}
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}
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}
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}
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}
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else
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{
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/*
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* Try to place the inode in its parent directory
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*/
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i = dir->i_block_group;
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tmp = get_group_desc (ITOV(dir)->v_mount, i, &bh2);
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if (tmp->bg_free_inodes_count)
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gdp = tmp;
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else
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{
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/*
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* Use a quadratic hash to find a group with a
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* free inode
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*/
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for (j = 1; j < sb->s_groups_count; j <<= 1) {
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i += j;
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if (i >= sb->s_groups_count)
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i -= sb->s_groups_count;
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tmp = get_group_desc(ITOV(dir)->v_mount,i,&bh2);
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if (tmp->bg_free_inodes_count) {
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gdp = tmp;
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break;
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}
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}
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}
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if (!gdp) {
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/*
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* That failed: try linear search for a free inode
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*/
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i = dir->i_block_group + 1;
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for (j = 2; j < sb->s_groups_count; j++) {
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if (++i >= sb->s_groups_count)
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i = 0;
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tmp = get_group_desc(ITOV(dir)->v_mount,i,&bh2);
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if (tmp->bg_free_inodes_count) {
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gdp = tmp;
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break;
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}
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}
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}
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}
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if (!gdp) {
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unlock_super (DEVVP(dir));
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return 0;
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}
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bitmap_nr = load_inode_bitmap (ITOV(dir)->v_mount, i);
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bh = sb->s_inode_bitmap[bitmap_nr];
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if ((j = find_first_zero_bit ((unsigned long *) bh->b_data,
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EXT2_INODES_PER_GROUP(sb))) <
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EXT2_INODES_PER_GROUP(sb)) {
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if (set_bit (j, bh->b_data)) {
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printf ( "ext2_new_inode:"
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"bit already set for inode %d", j);
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goto repeat;
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}
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/* Linux now does the following:
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mark_buffer_dirty(bh);
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if (sb->s_flags & MS_SYNCHRONOUS) {
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ll_rw_block (WRITE, 1, &bh);
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wait_on_buffer (bh);
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}
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*/
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mark_buffer_dirty(bh);
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} else {
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if (gdp->bg_free_inodes_count != 0) {
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printf ( "ext2_new_inode:"
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"Free inodes count corrupted in group %d",
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i);
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unlock_super (DEVVP(dir));
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return 0;
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}
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goto repeat;
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}
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j += i * EXT2_INODES_PER_GROUP(sb) + 1;
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if (j < EXT2_FIRST_INO || j > es->s_inodes_count) {
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printf ( "ext2_new_inode:"
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"reserved inode or inode > inodes count - "
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"block_group = %d,inode=%d", i, j);
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unlock_super (DEVVP(dir));
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return 0;
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}
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gdp->bg_free_inodes_count--;
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if (S_ISDIR(mode))
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gdp->bg_used_dirs_count++;
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mark_buffer_dirty(bh2);
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es->s_free_inodes_count--;
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/* mark_buffer_dirty(sb->u.ext2_sb.s_sbh, 1); */
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sb->s_dirt = 1;
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unlock_super (DEVVP(dir));
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return j;
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}
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#ifdef unused
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static unsigned long ext2_count_free_inodes (struct mount * mp)
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{
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#ifdef EXT2FS_DEBUG
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struct ext2_sb_info *sb = VFSTOEXT2(mp)->um_e2fs;
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struct ext2_super_block * es;
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unsigned long desc_count, bitmap_count, x;
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int bitmap_nr;
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struct ext2_group_desc * gdp;
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int i;
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lock_super (VFSTOEXT2(mp)->um_devvp);
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es = sb->s_es;
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desc_count = 0;
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bitmap_count = 0;
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gdp = NULL;
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for (i = 0; i < sb->s_groups_count; i++) {
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gdp = get_group_desc (mp, i, NULL);
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desc_count += gdp->bg_free_inodes_count;
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bitmap_nr = load_inode_bitmap (mp, i);
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x = ext2_count_free (sb->s_inode_bitmap[bitmap_nr],
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EXT2_INODES_PER_GROUP(sb) / 8);
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ext2_debug ("group %d: stored = %d, counted = %lu\n",
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i, gdp->bg_free_inodes_count, x);
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bitmap_count += x;
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}
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ext2_debug("stored = %lu, computed = %lu, %lu\n",
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es->s_free_inodes_count, desc_count, bitmap_count);
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unlock_super (VFSTOEXT2(mp)->um_devvp);
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return desc_count;
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#else
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return VFSTOEXT2(mp)->um_e2fsb->s_free_inodes_count;
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#endif
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}
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#endif /* unused */
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#ifdef LATER
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void ext2_check_inodes_bitmap (struct mount * mp)
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{
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struct ext2_super_block * es;
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unsigned long desc_count, bitmap_count, x;
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int bitmap_nr;
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struct ext2_group_desc * gdp;
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int i;
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lock_super (sb);
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es = sb->u.ext2_sb.s_es;
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desc_count = 0;
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bitmap_count = 0;
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gdp = NULL;
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for (i = 0; i < sb->u.ext2_sb.s_groups_count; i++) {
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gdp = get_group_desc (sb, i, NULL);
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desc_count += gdp->bg_free_inodes_count;
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bitmap_nr = load_inode_bitmap (sb, i);
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x = ext2_count_free (sb->u.ext2_sb.s_inode_bitmap[bitmap_nr],
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EXT2_INODES_PER_GROUP(sb) / 8);
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if (gdp->bg_free_inodes_count != x)
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printf ( "ext2_check_inodes_bitmap:"
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"Wrong free inodes count in group %d, "
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"stored = %d, counted = %lu", i,
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gdp->bg_free_inodes_count, x);
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bitmap_count += x;
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}
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if (es->s_free_inodes_count != bitmap_count)
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printf ( "ext2_check_inodes_bitmap:"
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"Wrong free inodes count in super block, "
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"stored = %lu, counted = %lu",
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(unsigned long) es->s_free_inodes_count, bitmap_count);
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unlock_super (sb);
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}
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#endif
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