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simons |
/*
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* linux/fs/sysv/ialloc.c
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*
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* minix/bitmap.c
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* ext/freelists.c
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* Copyright (C) 1992 Remy Card (card@masi.ibp.fr)
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*
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* xenix/alloc.c
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* Copyright (C) 1992 Doug Evans
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*
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* coh/alloc.c
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* Copyright (C) 1993 Pascal Haible, Bruno Haible
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*
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* sysv/ialloc.c
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* Copyright (C) 1993 Bruno Haible
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*
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* This file contains code for allocating/freeing inodes.
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*/
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/fs.h>
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#include <linux/sysv_fs.h>
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#include <linux/stddef.h>
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#include <linux/stat.h>
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#include <linux/string.h>
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#include <linux/locks.h>
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/* We don't trust the value of
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sb->sv_sbd2->s_tinode = *sb->sv_sb_total_free_inodes
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but we nevertheless keep it up to date. */
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/* An inode on disk is considered free if both i_mode == 0 and i_nlink == 0. */
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/* return &sb->sv_sb_fic_inodes[i] = &sbd->s_inode[i]; */
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static inline sysv_ino_t * sv_sb_fic_inode (struct super_block * sb, unsigned int i)
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{
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if (sb->sv_bh1 == sb->sv_bh2)
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return &sb->sv_sb_fic_inodes[i];
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else {
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/* 512 byte Xenix FS */
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unsigned int offset = offsetof(struct xenix_super_block, s_inode[i]);
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if (offset < 512)
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return (sysv_ino_t*)(sb->sv_sbd1 + offset);
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else
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return (sysv_ino_t*)(sb->sv_sbd2 + offset);
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}
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}
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void sysv_free_inode(struct inode * inode)
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{
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struct super_block * sb;
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unsigned int ino;
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struct buffer_head * bh;
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struct sysv_inode * raw_inode;
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if (!inode)
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return;
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if (!inode->i_dev) {
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printk("sysv_free_inode: inode has no device\n");
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return;
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}
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if (inode->i_count != 1) {
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printk("sysv_free_inode: inode has count=%ld\n", inode->i_count);
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return;
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}
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if (inode->i_nlink) {
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printk("sysv_free_inode: inode has nlink=%d\n", inode->i_nlink);
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return;
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}
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if (!(sb = inode->i_sb)) {
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printk("sysv_free_inode: inode on nonexistent device\n");
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return;
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}
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ino = inode->i_ino;
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if (ino <= SYSV_ROOT_INO || ino > sb->sv_ninodes) {
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printk("sysv_free_inode: inode 0,1,2 or nonexistent inode\n");
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return;
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}
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if (!(bh = sv_bread(sb, inode->i_dev, sb->sv_firstinodezone + ((ino-1) >> sb->sv_inodes_per_block_bits)))) {
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printk("sysv_free_inode: unable to read inode block on device "
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"%s\n", kdevname(inode->i_dev));
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clear_inode(inode);
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return;
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}
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raw_inode = (struct sysv_inode *) bh->b_data + ((ino-1) & sb->sv_inodes_per_block_1);
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lock_super(sb);
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if (*sb->sv_sb_fic_count < sb->sv_fic_size)
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*sv_sb_fic_inode(sb,(*sb->sv_sb_fic_count)++) = ino;
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(*sb->sv_sb_total_free_inodes)++;
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mark_buffer_dirty(sb->sv_bh1, 1); /* super-block has been modified */
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if (sb->sv_bh1 != sb->sv_bh2) mark_buffer_dirty(sb->sv_bh2, 1);
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sb->s_dirt = 1; /* and needs time stamp */
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memset(raw_inode, 0, sizeof(struct sysv_inode));
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mark_buffer_dirty(bh, 1);
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unlock_super(sb);
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brelse(bh);
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clear_inode(inode);
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}
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struct inode * sysv_new_inode(const struct inode * dir)
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{
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struct inode * inode;
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struct super_block * sb;
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struct buffer_head * bh;
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struct sysv_inode * raw_inode;
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int i,j,ino,block;
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if (!dir || !(inode = get_empty_inode()))
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return NULL;
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sb = dir->i_sb;
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inode->i_sb = sb;
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inode->i_flags = inode->i_sb->s_flags;
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lock_super(sb); /* protect against task switches */
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if ((*sb->sv_sb_fic_count == 0)
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|| (*sv_sb_fic_inode(sb,(*sb->sv_sb_fic_count)-1) == 0) /* Applies only to SystemV2 FS */
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) {
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/* Rebuild cache of free inodes: */
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/* i : index into cache slot being filled */
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/* ino : inode we are trying */
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/* block : firstinodezone + (ino-1)/inodes_per_block */
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/* j : (ino-1)%inodes_per_block */
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/* bh : buffer for block */
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/* raw_inode : pointer to inode ino in the block */
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for (i = 0, ino = SYSV_ROOT_INO+1, block = sb->sv_firstinodezone, j = SYSV_ROOT_INO ; i < sb->sv_fic_size && block < sb->sv_firstdatazone ; block++, j = 0) {
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if (!(bh = sv_bread(sb, sb->s_dev, block))) {
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printk("sysv_new_inode: unable to read inode table\n");
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break; /* go with what we've got */
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/* FIXME: Perhaps try the next block? */
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}
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raw_inode = (struct sysv_inode *) bh->b_data + j;
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for (; j < sb->sv_inodes_per_block && i < sb->sv_fic_size; ino++, j++, raw_inode++) {
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if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0)
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*sv_sb_fic_inode(sb,i++) = ino;
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}
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brelse(bh);
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}
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if (i == 0) {
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iput(inode);
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unlock_super(sb);
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return NULL; /* no inodes available */
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}
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*sb->sv_sb_fic_count = i;
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}
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/* Now *sb->sv_sb_fic_count > 0. */
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ino = *sv_sb_fic_inode(sb,--(*sb->sv_sb_fic_count));
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mark_buffer_dirty(sb->sv_bh1, 1); /* super-block has been modified */
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if (sb->sv_bh1 != sb->sv_bh2) mark_buffer_dirty(sb->sv_bh2, 1);
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sb->s_dirt = 1; /* and needs time stamp */
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inode->i_count = 1;
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inode->i_nlink = 1;
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inode->i_dev = sb->s_dev;
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inode->i_uid = current->fsuid;
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inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid;
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inode->i_dirt = 1;
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inode->i_ino = ino;
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inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
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inode->i_op = NULL;
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inode->i_blocks = inode->i_blksize = 0;
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insert_inode_hash(inode);
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/* Change directory entry: */
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inode->i_mode = 0; /* for sysv_write_inode() */
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inode->i_size = 0; /* ditto */
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sysv_write_inode(inode); /* ensure inode not allocated again */
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/* FIXME: caller may call this too. */
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inode->i_dirt = 1; /* cleared by sysv_write_inode() */
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/* That's it. */
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(*sb->sv_sb_total_free_inodes)--;
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mark_buffer_dirty(sb->sv_bh2, 1); /* super-block has been modified again */
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sb->s_dirt = 1; /* and needs time stamp again */
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unlock_super(sb);
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return inode;
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}
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unsigned long sysv_count_free_inodes(struct super_block * sb)
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{
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#if 1 /* test */
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struct buffer_head * bh;
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struct sysv_inode * raw_inode;
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int j,block,count;
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/* this causes a lot of disk traffic ... */
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count = 0;
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lock_super(sb);
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/* i : index into cache slot being filled */
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/* ino : inode we are trying */
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/* block : firstinodezone + (ino-1)/inodes_per_block */
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/* j : (ino-1)%inodes_per_block */
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/* bh : buffer for block */
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/* raw_inode : pointer to inode ino in the block */
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for (block = sb->sv_firstinodezone, j = SYSV_ROOT_INO ; block < sb->sv_firstdatazone ; block++, j = 0) {
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if (!(bh = sv_bread(sb, sb->s_dev, block))) {
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printk("sysv_count_free_inodes: unable to read inode table\n");
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break; /* go with what we've got */
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/* FIXME: Perhaps try the next block? */
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}
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raw_inode = (struct sysv_inode *) bh->b_data + j;
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for (; j < sb->sv_inodes_per_block ; j++, raw_inode++)
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if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0)
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count++;
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brelse(bh);
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}
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if (count != *sb->sv_sb_total_free_inodes) {
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printk("sysv_count_free_inodes: free inode count was %d, correcting to %d\n",(short)(*sb->sv_sb_total_free_inodes),count);
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if (!(sb->s_flags & MS_RDONLY)) {
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*sb->sv_sb_total_free_inodes = count;
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mark_buffer_dirty(sb->sv_bh2, 1); /* super-block has been modified */
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sb->s_dirt = 1; /* and needs time stamp */
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}
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}
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unlock_super(sb);
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return count;
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#else
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return *sb->sv_sb_total_free_inodes;
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#endif
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}
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