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         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
  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 |= MS_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.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  */
 109 static 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
 130 static 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
 148 static const struct inode_operations sysv_symlink_inode_operations = {
 149         .get_link       = page_get_link,
 150         .getattr        = sysv_getattr,
 151 };
 152
 153 void 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
 171 struct 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
 226 bad_inode:
 227         iget_failed(inode);
 228         return ERR_PTR(-EIO);
 229 }
 230
 231 static 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
 281 int 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
 286 int sysv_sync_inode(struct inode *inode)
 287 {
 288         return __sysv_write_inode(inode, 1);
 289 }
 290
 291 static 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
 304 static struct kmem_cache *sysv_inode_cachep;
 305
 306 static 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
 316 static 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
 322 static void sysv_destroy_inode(struct inode *inode)
 323 {
 324         call_rcu(&inode->i_rcu, sysv_i_callback);
 325 }
 326
 327 static 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
 334 const 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
 345 int __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
 356 void 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 }