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 #include <linux/fs_context.h> 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_init_fs_context(struct fs_context *fc); 24 25 static void efs_kill_sb(struct super_block *s) 26 { 27 struct efs_sb_info *sbi = SUPER_INFO(s); 28 kill_block_super(s); 29 kfree(sbi); 30 } 31 32 static struct pt_types sgi_pt_types[] = { 33 {0x00, "SGI vh"}, 34 {0x01, "SGI trkrepl"}, 35 {0x02, "SGI secrepl"}, 36 {0x03, "SGI raw"}, 37 {0x04, "SGI bsd"}, 38 {SGI_SYSV, "SGI sysv"}, 39 {0x06, "SGI vol"}, 40 {SGI_EFS, "SGI efs"}, 41 {0x08, "SGI lv"}, 42 {0x09, "SGI rlv"}, 43 {0x0A, "SGI xfs"}, 44 {0x0B, "SGI xfslog"}, 45 {0x0C, "SGI xlv"}, 46 {0x82, "Linux swap"}, 47 {0x83, "Linux native"}, 48 {0, NULL} 49 }; 50 51 /* 52 * File system definition and registration. 53 */ 54 static struct file_system_type efs_fs_type = { 55 .owner = THIS_MODULE, 56 .name = "efs", 57 .kill_sb = efs_kill_sb, 58 .fs_flags = FS_REQUIRES_DEV, 59 .init_fs_context = efs_init_fs_context, 60 }; 61 MODULE_ALIAS_FS("efs"); 62 63 static struct kmem_cache * efs_inode_cachep; 64 65 static struct inode *efs_alloc_inode(struct super_block *sb) 66 { 67 struct efs_inode_info *ei; 68 ei = alloc_inode_sb(sb, efs_inode_cachep, GFP_KERNEL); 69 if (!ei) 70 return NULL; 71 return &ei->vfs_inode; 72 } 73 74 static void efs_free_inode(struct inode *inode) 75 { 76 kmem_cache_free(efs_inode_cachep, INODE_INFO(inode)); 77 } 78 79 static void init_once(void *foo) 80 { 81 struct efs_inode_info *ei = (struct efs_inode_info *) foo; 82 83 inode_init_once(&ei->vfs_inode); 84 } 85 86 static int __init init_inodecache(void) 87 { 88 efs_inode_cachep = kmem_cache_create("efs_inode_cache", 89 sizeof(struct efs_inode_info), 0, 90 SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT, 91 init_once); 92 if (efs_inode_cachep == NULL) 93 return -ENOMEM; 94 return 0; 95 } 96 97 static void destroy_inodecache(void) 98 { 99 /* 100 * Make sure all delayed rcu free inodes are flushed before we 101 * destroy cache. 102 */ 103 rcu_barrier(); 104 kmem_cache_destroy(efs_inode_cachep); 105 } 106 107 static const struct super_operations efs_superblock_operations = { 108 .alloc_inode = efs_alloc_inode, 109 .free_inode = efs_free_inode, 110 .statfs = efs_statfs, 111 }; 112 113 static const struct export_operations efs_export_ops = { 114 .encode_fh = generic_encode_ino32_fh, 115 .fh_to_dentry = efs_fh_to_dentry, 116 .fh_to_parent = efs_fh_to_parent, 117 .get_parent = efs_get_parent, 118 }; 119 120 static int __init init_efs_fs(void) { 121 int err; 122 pr_info(EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n"); 123 err = init_inodecache(); 124 if (err) 125 goto out1; 126 err = register_filesystem(&efs_fs_type); 127 if (err) 128 goto out; 129 return 0; 130 out: 131 destroy_inodecache(); 132 out1: 133 return err; 134 } 135 136 static void __exit exit_efs_fs(void) { 137 unregister_filesystem(&efs_fs_type); 138 destroy_inodecache(); 139 } 140 141 module_init(init_efs_fs) 142 module_exit(exit_efs_fs) 143 144 static efs_block_t efs_validate_vh(struct volume_header *vh) { 145 int i; 146 __be32 cs, *ui; 147 int csum; 148 efs_block_t sblock = 0; /* shuts up gcc */ 149 struct pt_types *pt_entry; 150 int pt_type, slice = -1; 151 152 if (be32_to_cpu(vh->vh_magic) != VHMAGIC) { 153 /* 154 * assume that we're dealing with a partition and allow 155 * read_super() to try and detect a valid superblock 156 * on the next block. 157 */ 158 return 0; 159 } 160 161 ui = ((__be32 *) (vh + 1)) - 1; 162 for(csum = 0; ui >= ((__be32 *) vh);) { 163 cs = *ui--; 164 csum += be32_to_cpu(cs); 165 } 166 if (csum) { 167 pr_warn("SGI disklabel: checksum bad, label corrupted\n"); 168 return 0; 169 } 170 171 #ifdef DEBUG 172 pr_debug("bf: \"%16s\"\n", vh->vh_bootfile); 173 174 for(i = 0; i < NVDIR; i++) { 175 int j; 176 char name[VDNAMESIZE+1]; 177 178 for(j = 0; j < VDNAMESIZE; j++) { 179 name[j] = vh->vh_vd[i].vd_name[j]; 180 } 181 name[j] = (char) 0; 182 183 if (name[0]) { 184 pr_debug("vh: %8s block: 0x%08x size: 0x%08x\n", 185 name, (int) be32_to_cpu(vh->vh_vd[i].vd_lbn), 186 (int) be32_to_cpu(vh->vh_vd[i].vd_nbytes)); 187 } 188 } 189 #endif 190 191 for(i = 0; i < NPARTAB; i++) { 192 pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type); 193 for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) { 194 if (pt_type == pt_entry->pt_type) break; 195 } 196 #ifdef DEBUG 197 if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) { 198 pr_debug("pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n", 199 i, (int)be32_to_cpu(vh->vh_pt[i].pt_firstlbn), 200 (int)be32_to_cpu(vh->vh_pt[i].pt_nblks), 201 pt_type, (pt_entry->pt_name) ? 202 pt_entry->pt_name : "unknown"); 203 } 204 #endif 205 if (IS_EFS(pt_type)) { 206 sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn); 207 slice = i; 208 } 209 } 210 211 if (slice == -1) { 212 pr_notice("partition table contained no EFS partitions\n"); 213 #ifdef DEBUG 214 } else { 215 pr_info("using slice %d (type %s, offset 0x%x)\n", slice, 216 (pt_entry->pt_name) ? pt_entry->pt_name : "unknown", 217 sblock); 218 #endif 219 } 220 return sblock; 221 } 222 223 static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) { 224 225 if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic))) 226 return -1; 227 228 sb->fs_magic = be32_to_cpu(super->fs_magic); 229 sb->total_blocks = be32_to_cpu(super->fs_size); 230 sb->first_block = be32_to_cpu(super->fs_firstcg); 231 sb->group_size = be32_to_cpu(super->fs_cgfsize); 232 sb->data_free = be32_to_cpu(super->fs_tfree); 233 sb->inode_free = be32_to_cpu(super->fs_tinode); 234 sb->inode_blocks = be16_to_cpu(super->fs_cgisize); 235 sb->total_groups = be16_to_cpu(super->fs_ncg); 236 237 return 0; 238 } 239 240 static int efs_fill_super(struct super_block *s, struct fs_context *fc) 241 { 242 struct efs_sb_info *sb; 243 struct buffer_head *bh; 244 struct inode *root; 245 246 sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL); 247 if (!sb) 248 return -ENOMEM; 249 s->s_fs_info = sb; 250 s->s_time_min = 0; 251 s->s_time_max = U32_MAX; 252 253 s->s_magic = EFS_SUPER_MAGIC; 254 if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) { 255 pr_err("device does not support %d byte blocks\n", 256 EFS_BLOCKSIZE); 257 return invalf(fc, "device does not support %d byte blocks\n", 258 EFS_BLOCKSIZE); 259 } 260 261 /* read the vh (volume header) block */ 262 bh = sb_bread(s, 0); 263 264 if (!bh) { 265 pr_err("cannot read volume header\n"); 266 return -EIO; 267 } 268 269 /* 270 * if this returns zero then we didn't find any partition table. 271 * this isn't (yet) an error - just assume for the moment that 272 * the device is valid and go on to search for a superblock. 273 */ 274 sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data); 275 brelse(bh); 276 277 if (sb->fs_start == -1) { 278 return -EINVAL; 279 } 280 281 bh = sb_bread(s, sb->fs_start + EFS_SUPER); 282 if (!bh) { 283 pr_err("cannot read superblock\n"); 284 return -EIO; 285 } 286 287 if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) { 288 #ifdef DEBUG 289 pr_warn("invalid superblock at block %u\n", 290 sb->fs_start + EFS_SUPER); 291 #endif 292 brelse(bh); 293 return -EINVAL; 294 } 295 brelse(bh); 296 297 if (!sb_rdonly(s)) { 298 #ifdef DEBUG 299 pr_info("forcing read-only mode\n"); 300 #endif 301 s->s_flags |= SB_RDONLY; 302 } 303 s->s_op = &efs_superblock_operations; 304 s->s_export_op = &efs_export_ops; 305 root = efs_iget(s, EFS_ROOTINODE); 306 if (IS_ERR(root)) { 307 pr_err("get root inode failed\n"); 308 return PTR_ERR(root); 309 } 310 311 s->s_root = d_make_root(root); 312 if (!(s->s_root)) { 313 pr_err("get root dentry failed\n"); 314 return -ENOMEM; 315 } 316 317 return 0; 318 } 319 320 static int efs_get_tree(struct fs_context *fc) 321 { 322 return get_tree_bdev(fc, efs_fill_super); 323 } 324 325 static int efs_reconfigure(struct fs_context *fc) 326 { 327 sync_filesystem(fc->root->d_sb); 328 fc->sb_flags |= SB_RDONLY; 329 330 return 0; 331 } 332 333 static const struct fs_context_operations efs_context_opts = { 334 .get_tree = efs_get_tree, 335 .reconfigure = efs_reconfigure, 336 }; 337 338 /* 339 * Set up the filesystem mount context. 340 */ 341 static int efs_init_fs_context(struct fs_context *fc) 342 { 343 fc->ops = &efs_context_opts; 344 345 return 0; 346 } 347 348 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) { 349 struct super_block *sb = dentry->d_sb; 350 struct efs_sb_info *sbi = SUPER_INFO(sb); 351 u64 id = huge_encode_dev(sb->s_bdev->bd_dev); 352 353 buf->f_type = EFS_SUPER_MAGIC; /* efs magic number */ 354 buf->f_bsize = EFS_BLOCKSIZE; /* blocksize */ 355 buf->f_blocks = sbi->total_groups * /* total data blocks */ 356 (sbi->group_size - sbi->inode_blocks); 357 buf->f_bfree = sbi->data_free; /* free data blocks */ 358 buf->f_bavail = sbi->data_free; /* free blocks for non-root */ 359 buf->f_files = sbi->total_groups * /* total inodes */ 360 sbi->inode_blocks * 361 (EFS_BLOCKSIZE / sizeof(struct efs_dinode)); 362 buf->f_ffree = sbi->inode_free; /* free inodes */ 363 buf->f_fsid = u64_to_fsid(id); 364 buf->f_namelen = EFS_MAXNAMELEN; /* max filename length */ 365 366 return 0; 367 } 368 369