linux/fs/sysv/inode.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *  linux/fs/sysv/inode.c
   4 *
   5 *  minix/inode.c
   6 *  Copyright (C) 1991, 1992  Linus Torvalds
   7 *
   8 *  xenix/inode.c
   9 *  Copyright (C) 1992  Doug Evans
  10 *
  11 *  coh/inode.c
  12 *  Copyright (C) 1993  Pascal Haible, Bruno Haible
  13 *
  14 *  sysv/inode.c
  15 *  Copyright (C) 1993  Paul B. Monday
  16 *
  17 *  sysv/inode.c
  18 *  Copyright (C) 1993  Bruno Haible
  19 *  Copyright (C) 1997, 1998  Krzysztof G. Baranowski
  20 *
  21 *  This file contains code for allocating/freeing inodes and for read/writing
  22 *  the superblock.
  23 */
  24
  25#include <linux/highuid.h>
  26#include <linux/slab.h>
  27#include <linux/init.h>
  28#include <linux/buffer_head.h>
  29#include <linux/vfs.h>
  30#include <linux/writeback.h>
  31#include <linux/namei.h>
  32#include <asm/byteorder.h>
  33#include "sysv.h"
  34
  35static int sysv_sync_fs(struct super_block *sb, int wait)
  36{
  37        struct sysv_sb_info *sbi = SYSV_SB(sb);
  38        unsigned long time = get_seconds(), old_time;
  39
  40        mutex_lock(&sbi->s_lock);
  41
  42        /*
  43         * If we are going to write out the super block,
  44         * then attach current time stamp.
  45         * But if the filesystem was marked clean, keep it clean.
  46         */
  47        old_time = fs32_to_cpu(sbi, *sbi->s_sb_time);
  48        if (sbi->s_type == FSTYPE_SYSV4) {
  49                if (*sbi->s_sb_state == cpu_to_fs32(sbi, 0x7c269d38 - old_time))
  50                        *sbi->s_sb_state = cpu_to_fs32(sbi, 0x7c269d38 - time);
  51                *sbi->s_sb_time = cpu_to_fs32(sbi, time);
  52                mark_buffer_dirty(sbi->s_bh2);
  53        }
  54
  55        mutex_unlock(&sbi->s_lock);
  56
  57        return 0;
  58}
  59
  60static int sysv_remount(struct super_block *sb, int *flags, char *data)
  61{
  62        struct sysv_sb_info *sbi = SYSV_SB(sb);
  63
  64        sync_filesystem(sb);
  65        if (sbi->s_forced_ro)
  66                *flags |= SB_RDONLY;
  67        return 0;
  68}
  69
  70static void sysv_put_super(struct super_block *sb)
  71{
  72        struct sysv_sb_info *sbi = SYSV_SB(sb);
  73
  74        if (!sb_rdonly(sb)) {
  75                /* XXX ext2 also updates the state here */
  76                mark_buffer_dirty(sbi->s_bh1);
  77                if (sbi->s_bh1 != sbi->s_bh2)
  78                        mark_buffer_dirty(sbi->s_bh2);
  79        }
  80
  81        brelse(sbi->s_bh1);
  82        if (sbi->s_bh1 != sbi->s_bh2)
  83                brelse(sbi->s_bh2);
  84
  85        kfree(sbi);
  86}
  87
  88static int sysv_statfs(struct dentry *dentry, struct kstatfs *buf)
  89{
  90        struct super_block *sb = dentry->d_sb;
  91        struct sysv_sb_info *sbi = SYSV_SB(sb);
  92        u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
  93
  94        buf->f_type = sb->s_magic;
  95        buf->f_bsize = sb->s_blocksize;
  96        buf->f_blocks = sbi->s_ndatazones;
  97        buf->f_bavail = buf->f_bfree = sysv_count_free_blocks(sb);
  98        buf->f_files = sbi->s_ninodes;
  99        buf->f_ffree = sysv_count_free_inodes(sb);
 100        buf->f_namelen = SYSV_NAMELEN;
 101        buf->f_fsid.val[0] = (u32)id;
 102        buf->f_fsid.val[1] = (u32)(id >> 32);
 103        return 0;
 104}
 105
 106/* 
 107 * NXI <-> N0XI for PDP, XIN <-> XIN0 for le32, NIX <-> 0NIX for be32
 108 */
 109static inline void read3byte(struct sysv_sb_info *sbi,
 110        unsigned char * from, unsigned char * to)
 111{
 112        if (sbi->s_bytesex == BYTESEX_PDP) {
 113                to[0] = from[0];
 114                to[1] = 0;
 115                to[2] = from[1];
 116                to[3] = from[2];
 117        } else if (sbi->s_bytesex == BYTESEX_LE) {
 118                to[0] = from[0];
 119                to[1] = from[1];
 120                to[2] = from[2];
 121                to[3] = 0;
 122        } else {
 123                to[0] = 0;
 124                to[1] = from[0];
 125                to[2] = from[1];
 126                to[3] = from[2];
 127        }
 128}
 129
 130static inline void write3byte(struct sysv_sb_info *sbi,
 131        unsigned char * from, unsigned char * to)
 132{
 133        if (sbi->s_bytesex == BYTESEX_PDP) {
 134                to[0] = from[0];
 135                to[1] = from[2];
 136                to[2] = from[3];
 137        } else if (sbi->s_bytesex == BYTESEX_LE) {
 138                to[0] = from[0];
 139                to[1] = from[1];
 140                to[2] = from[2];
 141        } else {
 142                to[0] = from[1];
 143                to[1] = from[2];
 144                to[2] = from[3];
 145        }
 146}
 147
 148static const struct inode_operations sysv_symlink_inode_operations = {
 149        .get_link       = page_get_link,
 150        .getattr        = sysv_getattr,
 151};
 152
 153void sysv_set_inode(struct inode *inode, dev_t rdev)
 154{
 155        if (S_ISREG(inode->i_mode)) {
 156                inode->i_op = &sysv_file_inode_operations;
 157                inode->i_fop = &sysv_file_operations;
 158                inode->i_mapping->a_ops = &sysv_aops;
 159        } else if (S_ISDIR(inode->i_mode)) {
 160                inode->i_op = &sysv_dir_inode_operations;
 161                inode->i_fop = &sysv_dir_operations;
 162                inode->i_mapping->a_ops = &sysv_aops;
 163        } else if (S_ISLNK(inode->i_mode)) {
 164                inode->i_op = &sysv_symlink_inode_operations;
 165                inode_nohighmem(inode);
 166                inode->i_mapping->a_ops = &sysv_aops;
 167        } else
 168                init_special_inode(inode, inode->i_mode, rdev);
 169}
 170
 171struct inode *sysv_iget(struct super_block *sb, unsigned int ino)
 172{
 173        struct sysv_sb_info * sbi = SYSV_SB(sb);
 174        struct buffer_head * bh;
 175        struct sysv_inode * raw_inode;
 176        struct sysv_inode_info * si;
 177        struct inode *inode;
 178        unsigned int block;
 179
 180        if (!ino || ino > sbi->s_ninodes) {
 181                printk("Bad inode number on dev %s: %d is out of range\n",
 182                       sb->s_id, ino);
 183                return ERR_PTR(-EIO);
 184        }
 185
 186        inode = iget_locked(sb, ino);
 187        if (!inode)
 188                return ERR_PTR(-ENOMEM);
 189        if (!(inode->i_state & I_NEW))
 190                return inode;
 191
 192        raw_inode = sysv_raw_inode(sb, ino, &bh);
 193        if (!raw_inode) {
 194                printk("Major problem: unable to read inode from dev %s\n",
 195                       inode->i_sb->s_id);
 196                goto bad_inode;
 197        }
 198        /* SystemV FS: kludge permissions if ino==SYSV_ROOT_INO ?? */
 199        inode->i_mode = fs16_to_cpu(sbi, raw_inode->i_mode);
 200        i_uid_write(inode, (uid_t)fs16_to_cpu(sbi, raw_inode->i_uid));
 201        i_gid_write(inode, (gid_t)fs16_to_cpu(sbi, raw_inode->i_gid));
 202        set_nlink(inode, fs16_to_cpu(sbi, raw_inode->i_nlink));
 203        inode->i_size = fs32_to_cpu(sbi, raw_inode->i_size);
 204        inode->i_atime.tv_sec = fs32_to_cpu(sbi, raw_inode->i_atime);
 205        inode->i_mtime.tv_sec = fs32_to_cpu(sbi, raw_inode->i_mtime);
 206        inode->i_ctime.tv_sec = fs32_to_cpu(sbi, raw_inode->i_ctime);
 207        inode->i_ctime.tv_nsec = 0;
 208        inode->i_atime.tv_nsec = 0;
 209        inode->i_mtime.tv_nsec = 0;
 210        inode->i_blocks = 0;
 211
 212        si = SYSV_I(inode);
 213        for (block = 0; block < 10+1+1+1; block++)
 214                read3byte(sbi, &raw_inode->i_data[3*block],
 215                                (u8 *)&si->i_data[block]);
 216        brelse(bh);
 217        si->i_dir_start_lookup = 0;
 218        if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
 219                sysv_set_inode(inode,
 220                               old_decode_dev(fs32_to_cpu(sbi, si->i_data[0])));
 221        else
 222                sysv_set_inode(inode, 0);
 223        unlock_new_inode(inode);
 224        return inode;
 225
 226bad_inode:
 227        iget_failed(inode);
 228        return ERR_PTR(-EIO);
 229}
 230
 231static int __sysv_write_inode(struct inode *inode, int wait)
 232{
 233        struct super_block * sb = inode->i_sb;
 234        struct sysv_sb_info * sbi = SYSV_SB(sb);
 235        struct buffer_head * bh;
 236        struct sysv_inode * raw_inode;
 237        struct sysv_inode_info * si;
 238        unsigned int ino, block;
 239        int err = 0;
 240
 241        ino = inode->i_ino;
 242        if (!ino || ino > sbi->s_ninodes) {
 243                printk("Bad inode number on dev %s: %d is out of range\n",
 244                       inode->i_sb->s_id, ino);
 245                return -EIO;
 246        }
 247        raw_inode = sysv_raw_inode(sb, ino, &bh);
 248        if (!raw_inode) {
 249                printk("unable to read i-node block\n");
 250                return -EIO;
 251        }
 252
 253        raw_inode->i_mode = cpu_to_fs16(sbi, inode->i_mode);
 254        raw_inode->i_uid = cpu_to_fs16(sbi, fs_high2lowuid(i_uid_read(inode)));
 255        raw_inode->i_gid = cpu_to_fs16(sbi, fs_high2lowgid(i_gid_read(inode)));
 256        raw_inode->i_nlink = cpu_to_fs16(sbi, inode->i_nlink);
 257        raw_inode->i_size = cpu_to_fs32(sbi, inode->i_size);
 258        raw_inode->i_atime = cpu_to_fs32(sbi, inode->i_atime.tv_sec);
 259        raw_inode->i_mtime = cpu_to_fs32(sbi, inode->i_mtime.tv_sec);
 260        raw_inode->i_ctime = cpu_to_fs32(sbi, inode->i_ctime.tv_sec);
 261
 262        si = SYSV_I(inode);
 263        if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
 264                si->i_data[0] = cpu_to_fs32(sbi, old_encode_dev(inode->i_rdev));
 265        for (block = 0; block < 10+1+1+1; block++)
 266                write3byte(sbi, (u8 *)&si->i_data[block],
 267                        &raw_inode->i_data[3*block]);
 268        mark_buffer_dirty(bh);
 269        if (wait) {
 270                sync_dirty_buffer(bh);
 271                if (buffer_req(bh) && !buffer_uptodate(bh)) {
 272                        printk ("IO error syncing sysv inode [%s:%08x]\n",
 273                                sb->s_id, ino);
 274                        err = -EIO;
 275                }
 276        }
 277        brelse(bh);
 278        return 0;
 279}
 280
 281int sysv_write_inode(struct inode *inode, struct writeback_control *wbc)
 282{
 283        return __sysv_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
 284}
 285
 286int sysv_sync_inode(struct inode *inode)
 287{
 288        return __sysv_write_inode(inode, 1);
 289}
 290
 291static void sysv_evict_inode(struct inode *inode)
 292{
 293        truncate_inode_pages_final(&inode->i_data);
 294        if (!inode->i_nlink) {
 295                inode->i_size = 0;
 296                sysv_truncate(inode);
 297        }
 298        invalidate_inode_buffers(inode);
 299        clear_inode(inode);
 300        if (!inode->i_nlink)
 301                sysv_free_inode(inode);
 302}
 303
 304static struct kmem_cache *sysv_inode_cachep;
 305
 306static struct inode *sysv_alloc_inode(struct super_block *sb)
 307{
 308        struct sysv_inode_info *si;
 309
 310        si = kmem_cache_alloc(sysv_inode_cachep, GFP_KERNEL);
 311        if (!si)
 312                return NULL;
 313        return &si->vfs_inode;
 314}
 315
 316static void sysv_i_callback(struct rcu_head *head)
 317{
 318        struct inode *inode = container_of(head, struct inode, i_rcu);
 319        kmem_cache_free(sysv_inode_cachep, SYSV_I(inode));
 320}
 321
 322static void sysv_destroy_inode(struct inode *inode)
 323{
 324        call_rcu(&inode->i_rcu, sysv_i_callback);
 325}
 326
 327static void init_once(void *p)
 328{
 329        struct sysv_inode_info *si = (struct sysv_inode_info *)p;
 330
 331        inode_init_once(&si->vfs_inode);
 332}
 333
 334const struct super_operations sysv_sops = {
 335        .alloc_inode    = sysv_alloc_inode,
 336        .destroy_inode  = sysv_destroy_inode,
 337        .write_inode    = sysv_write_inode,
 338        .evict_inode    = sysv_evict_inode,
 339        .put_super      = sysv_put_super,
 340        .sync_fs        = sysv_sync_fs,
 341        .remount_fs     = sysv_remount,
 342        .statfs         = sysv_statfs,
 343};
 344
 345int __init sysv_init_icache(void)
 346{
 347        sysv_inode_cachep = kmem_cache_create("sysv_inode_cache",
 348                        sizeof(struct sysv_inode_info), 0,
 349                        SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|SLAB_ACCOUNT,
 350                        init_once);
 351        if (!sysv_inode_cachep)
 352                return -ENOMEM;
 353        return 0;
 354}
 355
 356void sysv_destroy_icache(void)
 357{
 358        /*
 359         * Make sure all delayed rcu free inodes are flushed before we
 360         * destroy cache.
 361         */
 362        rcu_barrier();
 363        kmem_cache_destroy(sysv_inode_cachep);
 364}
 365