fs/efs/super.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * super.c
   4  *
   5  * Copyright (c) 1999 Al Smith
   6  *
   7  * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
   8  */
   9
  10 #include <linux/init.h>
  11 #include <linux/module.h>
  12 #include <linux/exportfs.h>
  13 #include <linux/slab.h>
  14 #include <linux/buffer_head.h>
  15 #include <linux/vfs.h>
  16 #include <linux/blkdev.h>
  17
  18 #include "efs.h"
  19 #include <linux/efs_vh.h>
  20 #include <linux/efs_fs_sb.h>
  21
  22 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf);
  23 static int efs_fill_super(struct super_block *s, void *d, int silent);
  24
  25 static struct dentry *efs_mount(struct file_system_type *fs_type,
  26         int flags, const char *dev_name, void *data)
  27 {
  28         return mount_bdev(fs_type, flags, dev_name, data, efs_fill_super);
  29 }
  30
  31 static void efs_kill_sb(struct super_block *s)
  32 {
  33         struct efs_sb_info *sbi = SUPER_INFO(s);
  34         kill_block_super(s);
  35         kfree(sbi);
  36 }
  37
  38 static struct file_system_type efs_fs_type = {
  39         .owner          = THIS_MODULE,
  40         .name           = "efs",
  41         .mount          = efs_mount,
  42         .kill_sb        = efs_kill_sb,
  43         .fs_flags       = FS_REQUIRES_DEV,
  44 };
  45 MODULE_ALIAS_FS("efs");
  46
  47 static struct pt_types sgi_pt_types[] = {
  48         {0x00,          "SGI vh"},
  49         {0x01,          "SGI trkrepl"},
  50         {0x02,          "SGI secrepl"},
  51         {0x03,          "SGI raw"},
  52         {0x04,          "SGI bsd"},
  53         {SGI_SYSV,      "SGI sysv"},
  54         {0x06,          "SGI vol"},
  55         {SGI_EFS,       "SGI efs"},
  56         {0x08,          "SGI lv"},
  57         {0x09,          "SGI rlv"},
  58         {0x0A,          "SGI xfs"},
  59         {0x0B,          "SGI xfslog"},
  60         {0x0C,          "SGI xlv"},
  61         {0x82,          "Linux swap"},
  62         {0x83,          "Linux native"},
  63         {0,             NULL}
  64 };
  65
  66
  67 static struct kmem_cache * efs_inode_cachep;
  68
  69 static struct inode *efs_alloc_inode(struct super_block *sb)
  70 {
  71         struct efs_inode_info *ei;
  72         ei = kmem_cache_alloc(efs_inode_cachep, GFP_KERNEL);
  73         if (!ei)
  74                 return NULL;
  75         return &ei->vfs_inode;
  76 }
  77
  78 static void efs_free_inode(struct inode *inode)
  79 {
  80         kmem_cache_free(efs_inode_cachep, INODE_INFO(inode));
  81 }
  82
  83 static void init_once(void *foo)
  84 {
  85         struct efs_inode_info *ei = (struct efs_inode_info *) foo;
  86
  87         inode_init_once(&ei->vfs_inode);
  88 }
  89
  90 static int __init init_inodecache(void)
  91 {
  92         efs_inode_cachep = kmem_cache_create("efs_inode_cache",
  93                                 sizeof(struct efs_inode_info), 0,
  94                                 SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
  95                                 SLAB_ACCOUNT, init_once);
  96         if (efs_inode_cachep == NULL)
  97                 return -ENOMEM;
  98         return 0;
  99 }
 100
 101 static void destroy_inodecache(void)
 102 {
 103         /*
 104          * Make sure all delayed rcu free inodes are flushed before we
 105          * destroy cache.
 106          */
 107         rcu_barrier();
 108         kmem_cache_destroy(efs_inode_cachep);
 109 }
 110
 111 static int efs_remount(struct super_block *sb, int *flags, char *data)
 112 {
 113         sync_filesystem(sb);
 114         *flags |= SB_RDONLY;
 115         return 0;
 116 }
 117
 118 static const struct super_operations efs_superblock_operations = {
 119         .alloc_inode    = efs_alloc_inode,
 120         .free_inode     = efs_free_inode,
 121         .statfs         = efs_statfs,
 122         .remount_fs     = efs_remount,
 123 };
 124
 125 static const struct export_operations efs_export_ops = {
 126         .fh_to_dentry   = efs_fh_to_dentry,
 127         .fh_to_parent   = efs_fh_to_parent,
 128         .get_parent     = efs_get_parent,
 129 };
 130
 131 static int __init init_efs_fs(void) {
 132         int err;
 133         pr_info(EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
 134         err = init_inodecache();
 135         if (err)
 136                 goto out1;
 137         err = register_filesystem(&efs_fs_type);
 138         if (err)
 139                 goto out;
 140         return 0;
 141 out:
 142         destroy_inodecache();
 143 out1:
 144         return err;
 145 }
 146
 147 static void __exit exit_efs_fs(void) {
 148         unregister_filesystem(&efs_fs_type);
 149         destroy_inodecache();
 150 }
 151
 152 module_init(init_efs_fs)
 153 module_exit(exit_efs_fs)
 154
 155 static efs_block_t efs_validate_vh(struct volume_header *vh) {
 156         int             i;
 157         __be32          cs, *ui;
 158         int             csum;
 159         efs_block_t     sblock = 0; /* shuts up gcc */
 160         struct pt_types *pt_entry;
 161         int             pt_type, slice = -1;
 162
 163         if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
 164                 /*
 165                  * assume that we're dealing with a partition and allow
 166                  * read_super() to try and detect a valid superblock
 167                  * on the next block.
 168                  */
 169                 return 0;
 170         }
 171
 172         ui = ((__be32 *) (vh + 1)) - 1;
 173         for(csum = 0; ui >= ((__be32 *) vh);) {
 174                 cs = *ui--;
 175                 csum += be32_to_cpu(cs);
 176         }
 177         if (csum) {
 178                 pr_warn("SGI disklabel: checksum bad, label corrupted\n");
 179                 return 0;
 180         }
 181
 182 #ifdef DEBUG
 183         pr_debug("bf: \"%16s\"\n", vh->vh_bootfile);
 184
 185         for(i = 0; i < NVDIR; i++) {
 186                 int     j;
 187                 char    name[VDNAMESIZE+1];
 188
 189                 for(j = 0; j < VDNAMESIZE; j++) {
 190                         name[j] = vh->vh_vd[i].vd_name[j];
 191                 }
 192                 name[j] = (char) 0;
 193
 194                 if (name[0]) {
 195                         pr_debug("vh: %8s block: 0x%08x size: 0x%08x\n",
 196                                 name, (int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
 197                                 (int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
 198                 }
 199         }
 200 #endif
 201
 202         for(i = 0; i < NPARTAB; i++) {
 203                 pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
 204                 for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
 205                         if (pt_type == pt_entry->pt_type) break;
 206                 }
 207 #ifdef DEBUG
 208                 if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
 209                         pr_debug("pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
 210                                  i, (int)be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
 211                                  (int)be32_to_cpu(vh->vh_pt[i].pt_nblks),
 212                                  pt_type, (pt_entry->pt_name) ?
 213                                  pt_entry->pt_name : "unknown");
 214                 }
 215 #endif
 216                 if (IS_EFS(pt_type)) {
 217                         sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
 218                         slice = i;
 219                 }
 220         }
 221
 222         if (slice == -1) {
 223                 pr_notice("partition table contained no EFS partitions\n");
 224 #ifdef DEBUG
 225         } else {
 226                 pr_info("using slice %d (type %s, offset 0x%x)\n", slice,
 227                         (pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
 228                         sblock);
 229 #endif
 230         }
 231         return sblock;
 232 }
 233
 234 static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
 235
 236         if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic)))
 237                 return -1;
 238
 239         sb->fs_magic     = be32_to_cpu(super->fs_magic);
 240         sb->total_blocks = be32_to_cpu(super->fs_size);
 241         sb->first_block  = be32_to_cpu(super->fs_firstcg);
 242         sb->group_size   = be32_to_cpu(super->fs_cgfsize);
 243         sb->data_free    = be32_to_cpu(super->fs_tfree);
 244         sb->inode_free   = be32_to_cpu(super->fs_tinode);
 245         sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
 246         sb->total_groups = be16_to_cpu(super->fs_ncg);
 247
 248         return 0;
 249 }
 250
 251 static int efs_fill_super(struct super_block *s, void *d, int silent)
 252 {
 253         struct efs_sb_info *sb;
 254         struct buffer_head *bh;
 255         struct inode *root;
 256
 257         sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
 258         if (!sb)
 259                 return -ENOMEM;
 260         s->s_fs_info = sb;
 261         s->s_time_min = 0;
 262         s->s_time_max = U32_MAX;
 263
 264         s->s_magic              = EFS_SUPER_MAGIC;
 265         if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
 266                 pr_err("device does not support %d byte blocks\n",
 267                         EFS_BLOCKSIZE);
 268                 return -EINVAL;
 269         }
 270
 271         /* read the vh (volume header) block */
 272         bh = sb_bread(s, 0);
 273
 274         if (!bh) {
 275                 pr_err("cannot read volume header\n");
 276                 return -EIO;
 277         }
 278
 279         /*
 280          * if this returns zero then we didn't find any partition table.
 281          * this isn't (yet) an error - just assume for the moment that
 282          * the device is valid and go on to search for a superblock.
 283          */
 284         sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
 285         brelse(bh);
 286
 287         if (sb->fs_start == -1) {
 288                 return -EINVAL;
 289         }
 290
 291         bh = sb_bread(s, sb->fs_start + EFS_SUPER);
 292         if (!bh) {
 293                 pr_err("cannot read superblock\n");
 294                 return -EIO;
 295         }
 296
 297         if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
 298 #ifdef DEBUG
 299                 pr_warn("invalid superblock at block %u\n",
 300                         sb->fs_start + EFS_SUPER);
 301 #endif
 302                 brelse(bh);
 303                 return -EINVAL;
 304         }
 305         brelse(bh);
 306
 307         if (!sb_rdonly(s)) {
 308 #ifdef DEBUG
 309                 pr_info("forcing read-only mode\n");
 310 #endif
 311                 s->s_flags |= SB_RDONLY;
 312         }
 313         s->s_op   = &efs_superblock_operations;
 314         s->s_export_op = &efs_export_ops;
 315         root = efs_iget(s, EFS_ROOTINODE);
 316         if (IS_ERR(root)) {
 317                 pr_err("get root inode failed\n");
 318                 return PTR_ERR(root);
 319         }
 320
 321         s->s_root = d_make_root(root);
 322         if (!(s->s_root)) {
 323                 pr_err("get root dentry failed\n");
 324                 return -ENOMEM;
 325         }
 326
 327         return 0;
 328 }
 329
 330 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
 331         struct super_block *sb = dentry->d_sb;
 332         struct efs_sb_info *sbi = SUPER_INFO(sb);
 333         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 334
 335         buf->f_type    = EFS_SUPER_MAGIC;       /* efs magic number */
 336         buf->f_bsize   = EFS_BLOCKSIZE;         /* blocksize */
 337         buf->f_blocks  = sbi->total_groups *    /* total data blocks */
 338                         (sbi->group_size - sbi->inode_blocks);
 339         buf->f_bfree   = sbi->data_free;        /* free data blocks */
 340         buf->f_bavail  = sbi->data_free;        /* free blocks for non-root */
 341         buf->f_files   = sbi->total_groups *    /* total inodes */
 342                         sbi->inode_blocks *
 343                         (EFS_BLOCKSIZE / sizeof(struct efs_dinode));
 344         buf->f_ffree   = sbi->inode_free;       /* free inodes */
 345         buf->f_fsid    = u64_to_fsid(id);
 346         buf->f_namelen = EFS_MAXNAMELEN;        /* max filename length */
 347
 348         return 0;
 349 }
 350