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 17 #include "efs.h" 18 #include <linux/efs_vh.h> 19 #include <linux/efs_fs_sb.h> 20 21 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf); 22 static int efs_fill_super(struct super_block *s, void *d, int silent); 23 24 static struct dentry *efs_mount(struct file_system_type *fs_type, 25 int flags, const char *dev_name, void *data) 26 { 27 return mount_bdev(fs_type, flags, dev_name, data, efs_fill_super); 28 } 29 30 static void efs_kill_sb(struct super_block *s) 31 { 32 struct efs_sb_info *sbi = SUPER_INFO(s); 33 kill_block_super(s); 34 kfree(sbi); 35 } 36 37 static struct file_system_type efs_fs_type = { 38 .owner = THIS_MODULE, 39 .name = "efs", 40 .mount = efs_mount, 41 .kill_sb = efs_kill_sb, 42 .fs_flags = FS_REQUIRES_DEV, 43 }; 44 MODULE_ALIAS_FS("efs"); 45 46 static struct pt_types sgi_pt_types[] = { 47 {0x00, "SGI vh"}, 48 {0x01, "SGI trkrepl"}, 49 {0x02, "SGI secrepl"}, 50 {0x03, "SGI raw"}, 51 {0x04, "SGI bsd"}, 52 {SGI_SYSV, "SGI sysv"}, 53 {0x06, "SGI vol"}, 54 {SGI_EFS, "SGI efs"}, 55 {0x08, "SGI lv"}, 56 {0x09, "SGI rlv"}, 57 {0x0A, "SGI xfs"}, 58 {0x0B, "SGI xfslog"}, 59 {0x0C, "SGI xlv"}, 60 {0x82, "Linux swap"}, 61 {0x83, "Linux native"}, 62 {0, NULL} 63 }; 64 65 66 static struct kmem_cache * efs_inode_cachep; 67 68 static struct inode *efs_alloc_inode(struct super_block *sb) 69 { 70 struct efs_inode_info *ei; 71 ei = kmem_cache_alloc(efs_inode_cachep, GFP_KERNEL); 72 if (!ei) 73 return NULL; 74 return &ei->vfs_inode; 75 } 76 77 static void efs_i_callback(struct rcu_head *head) 78 { 79 struct inode *inode = container_of(head, struct inode, i_rcu); 80 kmem_cache_free(efs_inode_cachep, INODE_INFO(inode)); 81 } 82 83 static void efs_destroy_inode(struct inode *inode) 84 { 85 call_rcu(&inode->i_rcu, efs_i_callback); 86 } 87 88 static void init_once(void *foo) 89 { 90 struct efs_inode_info *ei = (struct efs_inode_info *) foo; 91 92 inode_init_once(&ei->vfs_inode); 93 } 94 95 static int __init init_inodecache(void) 96 { 97 efs_inode_cachep = kmem_cache_create("efs_inode_cache", 98 sizeof(struct efs_inode_info), 0, 99 SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD| 100 SLAB_ACCOUNT, init_once); 101 if (efs_inode_cachep == NULL) 102 return -ENOMEM; 103 return 0; 104 } 105 106 static void destroy_inodecache(void) 107 { 108 /* 109 * Make sure all delayed rcu free inodes are flushed before we 110 * destroy cache. 111 */ 112 rcu_barrier(); 113 kmem_cache_destroy(efs_inode_cachep); 114 } 115 116 static int efs_remount(struct super_block *sb, int *flags, char *data) 117 { 118 sync_filesystem(sb); 119 *flags |= SB_RDONLY; 120 return 0; 121 } 122 123 static const struct super_operations efs_superblock_operations = { 124 .alloc_inode = efs_alloc_inode, 125 .destroy_inode = efs_destroy_inode, 126 .statfs = efs_statfs, 127 .remount_fs = efs_remount, 128 }; 129 130 static const struct export_operations efs_export_ops = { 131 .fh_to_dentry = efs_fh_to_dentry, 132 .fh_to_parent = efs_fh_to_parent, 133 .get_parent = efs_get_parent, 134 }; 135 136 static int __init init_efs_fs(void) { 137 int err; 138 pr_info(EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n"); 139 err = init_inodecache(); 140 if (err) 141 goto out1; 142 err = register_filesystem(&efs_fs_type); 143 if (err) 144 goto out; 145 return 0; 146 out: 147 destroy_inodecache(); 148 out1: 149 return err; 150 } 151 152 static void __exit exit_efs_fs(void) { 153 unregister_filesystem(&efs_fs_type); 154 destroy_inodecache(); 155 } 156 157 module_init(init_efs_fs) 158 module_exit(exit_efs_fs) 159 160 static efs_block_t efs_validate_vh(struct volume_header *vh) { 161 int i; 162 __be32 cs, *ui; 163 int csum; 164 efs_block_t sblock = 0; /* shuts up gcc */ 165 struct pt_types *pt_entry; 166 int pt_type, slice = -1; 167 168 if (be32_to_cpu(vh->vh_magic) != VHMAGIC) { 169 /* 170 * assume that we're dealing with a partition and allow 171 * read_super() to try and detect a valid superblock 172 * on the next block. 173 */ 174 return 0; 175 } 176 177 ui = ((__be32 *) (vh + 1)) - 1; 178 for(csum = 0; ui >= ((__be32 *) vh);) { 179 cs = *ui--; 180 csum += be32_to_cpu(cs); 181 } 182 if (csum) { 183 pr_warn("SGI disklabel: checksum bad, label corrupted\n"); 184 return 0; 185 } 186 187 #ifdef DEBUG 188 pr_debug("bf: \"%16s\"\n", vh->vh_bootfile); 189 190 for(i = 0; i < NVDIR; i++) { 191 int j; 192 char name[VDNAMESIZE+1]; 193 194 for(j = 0; j < VDNAMESIZE; j++) { 195 name[j] = vh->vh_vd[i].vd_name[j]; 196 } 197 name[j] = (char) 0; 198 199 if (name[0]) { 200 pr_debug("vh: %8s block: 0x%08x size: 0x%08x\n", 201 name, (int) be32_to_cpu(vh->vh_vd[i].vd_lbn), 202 (int) be32_to_cpu(vh->vh_vd[i].vd_nbytes)); 203 } 204 } 205 #endif 206 207 for(i = 0; i < NPARTAB; i++) { 208 pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type); 209 for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) { 210 if (pt_type == pt_entry->pt_type) break; 211 } 212 #ifdef DEBUG 213 if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) { 214 pr_debug("pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n", 215 i, (int)be32_to_cpu(vh->vh_pt[i].pt_firstlbn), 216 (int)be32_to_cpu(vh->vh_pt[i].pt_nblks), 217 pt_type, (pt_entry->pt_name) ? 218 pt_entry->pt_name : "unknown"); 219 } 220 #endif 221 if (IS_EFS(pt_type)) { 222 sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn); 223 slice = i; 224 } 225 } 226 227 if (slice == -1) { 228 pr_notice("partition table contained no EFS partitions\n"); 229 #ifdef DEBUG 230 } else { 231 pr_info("using slice %d (type %s, offset 0x%x)\n", slice, 232 (pt_entry->pt_name) ? pt_entry->pt_name : "unknown", 233 sblock); 234 #endif 235 } 236 return sblock; 237 } 238 239 static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) { 240 241 if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic))) 242 return -1; 243 244 sb->fs_magic = be32_to_cpu(super->fs_magic); 245 sb->total_blocks = be32_to_cpu(super->fs_size); 246 sb->first_block = be32_to_cpu(super->fs_firstcg); 247 sb->group_size = be32_to_cpu(super->fs_cgfsize); 248 sb->data_free = be32_to_cpu(super->fs_tfree); 249 sb->inode_free = be32_to_cpu(super->fs_tinode); 250 sb->inode_blocks = be16_to_cpu(super->fs_cgisize); 251 sb->total_groups = be16_to_cpu(super->fs_ncg); 252 253 return 0; 254 } 255 256 static int efs_fill_super(struct super_block *s, void *d, int silent) 257 { 258 struct efs_sb_info *sb; 259 struct buffer_head *bh; 260 struct inode *root; 261 262 sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL); 263 if (!sb) 264 return -ENOMEM; 265 s->s_fs_info = sb; 266 267 s->s_magic = EFS_SUPER_MAGIC; 268 if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) { 269 pr_err("device does not support %d byte blocks\n", 270 EFS_BLOCKSIZE); 271 return -EINVAL; 272 } 273 274 /* read the vh (volume header) block */ 275 bh = sb_bread(s, 0); 276 277 if (!bh) { 278 pr_err("cannot read volume header\n"); 279 return -EIO; 280 } 281 282 /* 283 * if this returns zero then we didn't find any partition table. 284 * this isn't (yet) an error - just assume for the moment that 285 * the device is valid and go on to search for a superblock. 286 */ 287 sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data); 288 brelse(bh); 289 290 if (sb->fs_start == -1) { 291 return -EINVAL; 292 } 293 294 bh = sb_bread(s, sb->fs_start + EFS_SUPER); 295 if (!bh) { 296 pr_err("cannot read superblock\n"); 297 return -EIO; 298 } 299 300 if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) { 301 #ifdef DEBUG 302 pr_warn("invalid superblock at block %u\n", 303 sb->fs_start + EFS_SUPER); 304 #endif 305 brelse(bh); 306 return -EINVAL; 307 } 308 brelse(bh); 309 310 if (!sb_rdonly(s)) { 311 #ifdef DEBUG 312 pr_info("forcing read-only mode\n"); 313 #endif 314 s->s_flags |= SB_RDONLY; 315 } 316 s->s_op = &efs_superblock_operations; 317 s->s_export_op = &efs_export_ops; 318 root = efs_iget(s, EFS_ROOTINODE); 319 if (IS_ERR(root)) { 320 pr_err("get root inode failed\n"); 321 return PTR_ERR(root); 322 } 323 324 s->s_root = d_make_root(root); 325 if (!(s->s_root)) { 326 pr_err("get root dentry failed\n"); 327 return -ENOMEM; 328 } 329 330 return 0; 331 } 332 333 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) { 334 struct super_block *sb = dentry->d_sb; 335 struct efs_sb_info *sbi = SUPER_INFO(sb); 336 u64 id = huge_encode_dev(sb->s_bdev->bd_dev); 337 338 buf->f_type = EFS_SUPER_MAGIC; /* efs magic number */ 339 buf->f_bsize = EFS_BLOCKSIZE; /* blocksize */ 340 buf->f_blocks = sbi->total_groups * /* total data blocks */ 341 (sbi->group_size - sbi->inode_blocks); 342 buf->f_bfree = sbi->data_free; /* free data blocks */ 343 buf->f_bavail = sbi->data_free; /* free blocks for non-root */ 344 buf->f_files = sbi->total_groups * /* total inodes */ 345 sbi->inode_blocks * 346 (EFS_BLOCKSIZE / sizeof(struct efs_dinode)); 347 buf->f_ffree = sbi->inode_free; /* free inodes */ 348 buf->f_fsid.val[0] = (u32)id; 349 buf->f_fsid.val[1] = (u32)(id >> 32); 350 buf->f_namelen = EFS_MAXNAMELEN; /* max filename length */ 351 352 return 0; 353 } 354 355