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 } 350 351