fs/sysv/inode.c

   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
  35 static int sysv_sync_fs(struct super_block *sb, int wait)
  36 {
  37         struct sysv_sb_info *sbi = SYSV_SB(sb);
  38         u32 time = (u32)ktime_get_real_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, 0x7c269d38u - old_time))
  50                         *sbi->s_sb_state = cpu_to_fs32(sbi, 0x7c269d38u - 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
  60 static 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
  70 static 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
  88 static 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 = u64_to_fsid(id);
 102         return 0;
 103 }
 104
 105 /*
 106  * NXI <-> N0XI for PDP, XIN <-> XIN0 for le32, NIX <-> 0NIX for be32
 107  */
 108 static inline void read3byte(struct sysv_sb_info *sbi,
 109         unsigned char * from, unsigned char * to)
 110 {
 111         if (sbi->s_bytesex == BYTESEX_PDP) {
 112                 to[0] = from[0];
 113                 to[1] = 0;
 114                 to[2] = from[1];
 115                 to[3] = from[2];
 116         } else if (sbi->s_bytesex == BYTESEX_LE) {
 117                 to[0] = from[0];
 118                 to[1] = from[1];
 119                 to[2] = from[2];
 120                 to[3] = 0;
 121         } else {
 122                 to[0] = 0;
 123                 to[1] = from[0];
 124                 to[2] = from[1];
 125                 to[3] = from[2];
 126         }
 127 }
 128
 129 static inline void write3byte(struct sysv_sb_info *sbi,
 130         unsigned char * from, unsigned char * to)
 131 {
 132         if (sbi->s_bytesex == BYTESEX_PDP) {
 133                 to[0] = from[0];
 134                 to[1] = from[2];
 135                 to[2] = from[3];
 136         } else if (sbi->s_bytesex == BYTESEX_LE) {
 137                 to[0] = from[0];
 138                 to[1] = from[1];
 139                 to[2] = from[2];
 140         } else {
 141                 to[0] = from[1];
 142                 to[1] = from[2];
 143                 to[2] = from[3];
 144         }
 145 }
 146
 147 static const struct inode_operations sysv_symlink_inode_operations = {
 148         .get_link       = page_get_link,
 149         .getattr        = sysv_getattr,
 150 };
 151
 152 void sysv_set_inode(struct inode *inode, dev_t rdev)
 153 {
 154         if (S_ISREG(inode->i_mode)) {
 155                 inode->i_op = &sysv_file_inode_operations;
 156                 inode->i_fop = &sysv_file_operations;
 157                 inode->i_mapping->a_ops = &sysv_aops;
 158         } else if (S_ISDIR(inode->i_mode)) {
 159                 inode->i_op = &sysv_dir_inode_operations;
 160                 inode->i_fop = &sysv_dir_operations;
 161                 inode->i_mapping->a_ops = &sysv_aops;
 162         } else if (S_ISLNK(inode->i_mode)) {
 163                 inode->i_op = &sysv_symlink_inode_operations;
 164                 inode_nohighmem(inode);
 165                 inode->i_mapping->a_ops = &sysv_aops;
 166         } else
 167                 init_special_inode(inode, inode->i_mode, rdev);
 168 }
 169
 170 struct inode *sysv_iget(struct super_block *sb, unsigned int ino)
 171 {
 172         struct sysv_sb_info * sbi = SYSV_SB(sb);
 173         struct buffer_head * bh;
 174         struct sysv_inode * raw_inode;
 175         struct sysv_inode_info * si;
 176         struct inode *inode;
 177         unsigned int block;
 178
 179         if (!ino || ino > sbi->s_ninodes) {
 180                 printk("Bad inode number on dev %s: %d is out of range\n",
 181                        sb->s_id, ino);
 182                 return ERR_PTR(-EIO);
 183         }
 184
 185         inode = iget_locked(sb, ino);
 186         if (!inode)
 187                 return ERR_PTR(-ENOMEM);
 188         if (!(inode->i_state & I_NEW))
 189                 return inode;
 190
 191         raw_inode = sysv_raw_inode(sb, ino, &bh);
 192         if (!raw_inode) {
 193                 printk("Major problem: unable to read inode from dev %s\n",
 194                        inode->i_sb->s_id);
 195                 goto bad_inode;
 196         }
 197         /* SystemV FS: kludge permissions if ino==SYSV_ROOT_INO ?? */
 198         inode->i_mode = fs16_to_cpu(sbi, raw_inode->i_mode);
 199         i_uid_write(inode, (uid_t)fs16_to_cpu(sbi, raw_inode->i_uid));
 200         i_gid_write(inode, (gid_t)fs16_to_cpu(sbi, raw_inode->i_gid));
 201         set_nlink(inode, fs16_to_cpu(sbi, raw_inode->i_nlink));
 202         inode->i_size = fs32_to_cpu(sbi, raw_inode->i_size);
 203         inode_set_atime(inode, fs32_to_cpu(sbi, raw_inode->i_atime), 0);
 204         inode_set_mtime(inode, fs32_to_cpu(sbi, raw_inode->i_mtime), 0);
 205         inode_set_ctime(inode, fs32_to_cpu(sbi, raw_inode->i_ctime), 0);
 206         inode->i_blocks = 0;
 207
 208         si = SYSV_I(inode);
 209         for (block = 0; block < 10+1+1+1; block++)
 210                 read3byte(sbi, &raw_inode->i_data[3*block],
 211                                 (u8 *)&si->i_data[block]);
 212         brelse(bh);
 213         si->i_dir_start_lookup = 0;
 214         if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
 215                 sysv_set_inode(inode,
 216                                old_decode_dev(fs32_to_cpu(sbi, si->i_data[0])));
 217         else
 218                 sysv_set_inode(inode, 0);
 219         unlock_new_inode(inode);
 220         return inode;
 221
 222 bad_inode:
 223         iget_failed(inode);
 224         return ERR_PTR(-EIO);
 225 }
 226
 227 static int __sysv_write_inode(struct inode *inode, int wait)
 228 {
 229         struct super_block * sb = inode->i_sb;
 230         struct sysv_sb_info * sbi = SYSV_SB(sb);
 231         struct buffer_head * bh;
 232         struct sysv_inode * raw_inode;
 233         struct sysv_inode_info * si;
 234         unsigned int ino, block;
 235         int err = 0;
 236
 237         ino = inode->i_ino;
 238         if (!ino || ino > sbi->s_ninodes) {
 239                 printk("Bad inode number on dev %s: %d is out of range\n",
 240                        inode->i_sb->s_id, ino);
 241                 return -EIO;
 242         }
 243         raw_inode = sysv_raw_inode(sb, ino, &bh);
 244         if (!raw_inode) {
 245                 printk("unable to read i-node block\n");
 246                 return -EIO;
 247         }
 248
 249         raw_inode->i_mode = cpu_to_fs16(sbi, inode->i_mode);
 250         raw_inode->i_uid = cpu_to_fs16(sbi, fs_high2lowuid(i_uid_read(inode)));
 251         raw_inode->i_gid = cpu_to_fs16(sbi, fs_high2lowgid(i_gid_read(inode)));
 252         raw_inode->i_nlink = cpu_to_fs16(sbi, inode->i_nlink);
 253         raw_inode->i_size = cpu_to_fs32(sbi, inode->i_size);
 254         raw_inode->i_atime = cpu_to_fs32(sbi, inode_get_atime_sec(inode));
 255         raw_inode->i_mtime = cpu_to_fs32(sbi, inode_get_mtime_sec(inode));
 256         raw_inode->i_ctime = cpu_to_fs32(sbi, inode_get_ctime_sec(inode));
 257
 258         si = SYSV_I(inode);
 259         if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
 260                 si->i_data[0] = cpu_to_fs32(sbi, old_encode_dev(inode->i_rdev));
 261         for (block = 0; block < 10+1+1+1; block++)
 262                 write3byte(sbi, (u8 *)&si->i_data[block],
 263                         &raw_inode->i_data[3*block]);
 264         mark_buffer_dirty(bh);
 265         if (wait) {
 266                 sync_dirty_buffer(bh);
 267                 if (buffer_req(bh) && !buffer_uptodate(bh)) {
 268                         printk ("IO error syncing sysv inode [%s:%08x]\n",
 269                                 sb->s_id, ino);
 270                         err = -EIO;
 271                 }
 272         }
 273         brelse(bh);
 274         return err;
 275 }
 276
 277 int sysv_write_inode(struct inode *inode, struct writeback_control *wbc)
 278 {
 279         return __sysv_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
 280 }
 281
 282 int sysv_sync_inode(struct inode *inode)
 283 {
 284         return __sysv_write_inode(inode, 1);
 285 }
 286
 287 static void sysv_evict_inode(struct inode *inode)
 288 {
 289         truncate_inode_pages_final(&inode->i_data);
 290         if (!inode->i_nlink) {
 291                 inode->i_size = 0;
 292                 sysv_truncate(inode);
 293         }
 294         invalidate_inode_buffers(inode);
 295         clear_inode(inode);
 296         if (!inode->i_nlink)
 297                 sysv_free_inode(inode);
 298 }
 299
 300 static struct kmem_cache *sysv_inode_cachep;
 301
 302 static struct inode *sysv_alloc_inode(struct super_block *sb)
 303 {
 304         struct sysv_inode_info *si;
 305
 306         si = alloc_inode_sb(sb, sysv_inode_cachep, GFP_KERNEL);
 307         if (!si)
 308                 return NULL;
 309         return &si->vfs_inode;
 310 }
 311
 312 static void sysv_free_in_core_inode(struct inode *inode)
 313 {
 314         kmem_cache_free(sysv_inode_cachep, SYSV_I(inode));
 315 }
 316
 317 static void init_once(void *p)
 318 {
 319         struct sysv_inode_info *si = (struct sysv_inode_info *)p;
 320
 321         inode_init_once(&si->vfs_inode);
 322 }
 323
 324 const struct super_operations sysv_sops = {
 325         .alloc_inode    = sysv_alloc_inode,
 326         .free_inode     = sysv_free_in_core_inode,
 327         .write_inode    = sysv_write_inode,
 328         .evict_inode    = sysv_evict_inode,
 329         .put_super      = sysv_put_super,
 330         .sync_fs        = sysv_sync_fs,
 331         .remount_fs     = sysv_remount,
 332         .statfs         = sysv_statfs,
 333 };
 334
 335 int __init sysv_init_icache(void)
 336 {
 337         sysv_inode_cachep = kmem_cache_create("sysv_inode_cache",
 338                         sizeof(struct sysv_inode_info), 0,
 339                         SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
 340                         init_once);
 341         if (!sysv_inode_cachep)
 342                 return -ENOMEM;
 343         return 0;
 344 }
 345
 346 void sysv_destroy_icache(void)
 347 {
 348         /*
 349          * Make sure all delayed rcu free inodes are flushed before we
 350          * destroy cache.
 351          */
 352         rcu_barrier();
 353         kmem_cache_destroy(sysv_inode_cachep);
 354 }