1/* 2 * linux/fs/sysv/ialloc.c 3 * 4 * minix/bitmap.c 5 * Copyright (C) 1991, 1992 Linus Torvalds 6 * 7 * ext/freelists.c 8 * Copyright (C) 1992 Remy Card (card@masi.ibp.fr) 9 * 10 * xenix/alloc.c 11 * Copyright (C) 1992 Doug Evans 12 * 13 * coh/alloc.c 14 * Copyright (C) 1993 Pascal Haible, Bruno Haible 15 * 16 * sysv/ialloc.c 17 * Copyright (C) 1993 Bruno Haible 18 * 19 * This file contains code for allocating/freeing inodes. 20 */ 21 22#include <linux/kernel.h> 23#include <linux/stddef.h> 24#include <linux/sched.h> 25#include <linux/stat.h> 26#include <linux/string.h> 27#include <linux/buffer_head.h> 28#include <linux/writeback.h> 29#include "sysv.h" 30 31/* We don't trust the value of 32 sb->sv_sbd2->s_tinode = *sb->sv_sb_total_free_inodes 33 but we nevertheless keep it up to date. */ 34 35/* An inode on disk is considered free if both i_mode == 0 and i_nlink == 0. */ 36 37/* return &sb->sv_sb_fic_inodes[i] = &sbd->s_inode[i]; */ 38static inline sysv_ino_t * 39sv_sb_fic_inode(struct super_block * sb, unsigned int i) 40{ 41 struct sysv_sb_info *sbi = SYSV_SB(sb); 42 43 if (sbi->s_bh1 == sbi->s_bh2) 44 return &sbi->s_sb_fic_inodes[i]; 45 else { 46 /* 512 byte Xenix FS */ 47 unsigned int offset = offsetof(struct xenix_super_block, s_inode[i]); 48 if (offset < 512) 49 return (sysv_ino_t*)(sbi->s_sbd1 + offset); 50 else 51 return (sysv_ino_t*)(sbi->s_sbd2 + offset); 52 } 53} 54 55struct sysv_inode * 56sysv_raw_inode(struct super_block *sb, unsigned ino, struct buffer_head **bh) 57{ 58 struct sysv_sb_info *sbi = SYSV_SB(sb); 59 struct sysv_inode *res; 60 int block = sbi->s_firstinodezone + sbi->s_block_base; 61 62 block += (ino-1) >> sbi->s_inodes_per_block_bits; 63 *bh = sb_bread(sb, block); 64 if (!*bh) 65 return NULL; 66 res = (struct sysv_inode *)(*bh)->b_data; 67 return res + ((ino-1) & sbi->s_inodes_per_block_1); 68} 69 70static int refill_free_cache(struct super_block *sb) 71{ 72 struct sysv_sb_info *sbi = SYSV_SB(sb); 73 struct buffer_head * bh; 74 struct sysv_inode * raw_inode; 75 int i = 0, ino; 76 77 ino = SYSV_ROOT_INO+1; 78 raw_inode = sysv_raw_inode(sb, ino, &bh); 79 if (!raw_inode) 80 goto out; 81 while (ino <= sbi->s_ninodes) { 82 if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0) { 83 *sv_sb_fic_inode(sb,i++) = cpu_to_fs16(SYSV_SB(sb), ino); 84 if (i == sbi->s_fic_size) 85 break; 86 } 87 if ((ino++ & sbi->s_inodes_per_block_1) == 0) { 88 brelse(bh); 89 raw_inode = sysv_raw_inode(sb, ino, &bh); 90 if (!raw_inode) 91 goto out; 92 } else 93 raw_inode++; 94 } 95 brelse(bh); 96out: 97 return i; 98} 99 100void sysv_free_inode(struct inode * inode) 101{ 102 struct super_block *sb = inode->i_sb; 103 struct sysv_sb_info *sbi = SYSV_SB(sb); 104 unsigned int ino; 105 struct buffer_head * bh; 106 struct sysv_inode * raw_inode; 107 unsigned count; 108 109 sb = inode->i_sb; 110 ino = inode->i_ino; 111 if (ino <= SYSV_ROOT_INO || ino > sbi->s_ninodes) { 112 printk("sysv_free_inode: inode 0,1,2 or nonexistent inode\n"); 113 return; 114 } 115 raw_inode = sysv_raw_inode(sb, ino, &bh); 116 if (!raw_inode) { 117 printk("sysv_free_inode: unable to read inode block on device " 118 "%s\n", inode->i_sb->s_id); 119 return; 120 } 121 lock_super(sb); 122 count = fs16_to_cpu(sbi, *sbi->s_sb_fic_count); 123 if (count < sbi->s_fic_size) { 124 *sv_sb_fic_inode(sb,count++) = cpu_to_fs16(sbi, ino); 125 *sbi->s_sb_fic_count = cpu_to_fs16(sbi, count); 126 } 127 fs16_add(sbi, sbi->s_sb_total_free_inodes, 1); 128 dirty_sb(sb); 129 memset(raw_inode, 0, sizeof(struct sysv_inode)); 130 mark_buffer_dirty(bh); 131 unlock_super(sb); 132 brelse(bh); 133} 134 135struct inode * sysv_new_inode(const struct inode * dir, mode_t mode) 136{ 137 struct super_block *sb = dir->i_sb; 138 struct sysv_sb_info *sbi = SYSV_SB(sb); 139 struct inode *inode; 140 sysv_ino_t ino; 141 unsigned count; 142 struct writeback_control wbc = { 143 .sync_mode = WB_SYNC_NONE 144 }; 145 146 inode = new_inode(sb); 147 if (!inode) 148 return ERR_PTR(-ENOMEM); 149 150 lock_super(sb); 151 count = fs16_to_cpu(sbi, *sbi->s_sb_fic_count); 152 if (count == 0 || (*sv_sb_fic_inode(sb,count-1) == 0)) { 153 count = refill_free_cache(sb); 154 if (count == 0) { 155 iput(inode); 156 unlock_super(sb); 157 return ERR_PTR(-ENOSPC); 158 } 159 } 160 /* Now count > 0. */ 161 ino = *sv_sb_fic_inode(sb,--count); 162 *sbi->s_sb_fic_count = cpu_to_fs16(sbi, count); 163 fs16_add(sbi, sbi->s_sb_total_free_inodes, -1); 164 dirty_sb(sb); 165 inode_init_owner(inode, dir, mode); 166 inode->i_ino = fs16_to_cpu(sbi, ino); 167 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC; 168 inode->i_blocks = 0; 169 memset(SYSV_I(inode)->i_data, 0, sizeof(SYSV_I(inode)->i_data)); 170 SYSV_I(inode)->i_dir_start_lookup = 0; 171 insert_inode_hash(inode); 172 mark_inode_dirty(inode); 173 174 sysv_write_inode(inode, &wbc); /* ensure inode not allocated again */ 175 mark_inode_dirty(inode); /* cleared by sysv_write_inode() */ 176 /* That's it. */ 177 unlock_super(sb); 178 return inode; 179} 180 181unsigned long sysv_count_free_inodes(struct super_block * sb) 182{ 183 struct sysv_sb_info *sbi = SYSV_SB(sb); 184 struct buffer_head * bh; 185 struct sysv_inode * raw_inode; 186 int ino, count, sb_count; 187 188 lock_super(sb); 189 190 sb_count = fs16_to_cpu(sbi, *sbi->s_sb_total_free_inodes); 191 192 if (0) 193 goto trust_sb; 194 195 /* this causes a lot of disk traffic ... */ 196 count = 0; 197 ino = SYSV_ROOT_INO+1; 198 raw_inode = sysv_raw_inode(sb, ino, &bh); 199 if (!raw_inode) 200 goto Eio; 201 while (ino <= sbi->s_ninodes) { 202 if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0) 203 count++; 204 if ((ino++ & sbi->s_inodes_per_block_1) == 0) { 205 brelse(bh); 206 raw_inode = sysv_raw_inode(sb, ino, &bh); 207 if (!raw_inode) 208 goto Eio; 209 } else 210 raw_inode++; 211 } 212 brelse(bh); 213 if (count != sb_count) 214 goto Einval; 215out: 216 unlock_super(sb); 217 return count; 218 219Einval: 220 printk("sysv_count_free_inodes: " 221 "free inode count was %d, correcting to %d\n", 222 sb_count, count); 223 if (!(sb->s_flags & MS_RDONLY)) { 224 *sbi->s_sb_total_free_inodes = cpu_to_fs16(SYSV_SB(sb), count); 225 dirty_sb(sb); 226 } 227 goto out; 228 229Eio: 230 printk("sysv_count_free_inodes: unable to read inode table\n"); 231trust_sb: 232 count = sb_count; 233 goto out; 234} 235