1 /* 2 * Copyright (C) 2007 Oracle. All rights reserved. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public 6 * License v2 as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 * General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public 14 * License along with this program; if not, write to the 15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, 16 * Boston, MA 021110-1307, USA. 17 */ 18 19 #include <linux/blkdev.h> 20 #include <linux/module.h> 21 #include <linux/buffer_head.h> 22 #include <linux/fs.h> 23 #include <linux/pagemap.h> 24 #include <linux/highmem.h> 25 #include <linux/time.h> 26 #include <linux/init.h> 27 #include <linux/string.h> 28 #include <linux/smp_lock.h> 29 #include <linux/backing-dev.h> 30 #include <linux/mount.h> 31 #include <linux/mpage.h> 32 #include <linux/swap.h> 33 #include <linux/writeback.h> 34 #include <linux/statfs.h> 35 #include <linux/compat.h> 36 #include <linux/parser.h> 37 #include <linux/ctype.h> 38 #include <linux/namei.h> 39 #include "ctree.h" 40 #include "disk-io.h" 41 #include "transaction.h" 42 #include "btrfs_inode.h" 43 #include "ioctl.h" 44 #include "print-tree.h" 45 #include "xattr.h" 46 47 #define BTRFS_SUPER_MAGIC 0x9123683E 48 49 static struct super_operations btrfs_super_ops; 50 51 static void btrfs_put_super (struct super_block * sb) 52 { 53 struct btrfs_root *root = btrfs_sb(sb); 54 struct btrfs_fs_info *fs = root->fs_info; 55 int ret; 56 57 ret = close_ctree(root); 58 if (ret) { 59 printk("close ctree returns %d\n", ret); 60 } 61 btrfs_sysfs_del_super(fs); 62 sb->s_fs_info = NULL; 63 } 64 65 enum { 66 Opt_subvol, Opt_nodatasum, Opt_nodatacow, Opt_max_extent, 67 Opt_alloc_start, Opt_nobarrier, Opt_ssd, Opt_err, 68 }; 69 70 static match_table_t tokens = { 71 {Opt_subvol, "subvol=%s"}, 72 {Opt_nodatasum, "nodatasum"}, 73 {Opt_nodatacow, "nodatacow"}, 74 {Opt_nobarrier, "nobarrier"}, 75 {Opt_max_extent, "max_extent=%s"}, 76 {Opt_alloc_start, "alloc_start=%s"}, 77 {Opt_ssd, "ssd"}, 78 {Opt_err, NULL} 79 }; 80 81 u64 btrfs_parse_size(char *str) 82 { 83 u64 res; 84 int mult = 1; 85 char *end; 86 char last; 87 88 res = simple_strtoul(str, &end, 10); 89 90 last = end[0]; 91 if (isalpha(last)) { 92 last = tolower(last); 93 switch (last) { 94 case 'g': 95 mult *= 1024; 96 case 'm': 97 mult *= 1024; 98 case 'k': 99 mult *= 1024; 100 } 101 res = res * mult; 102 } 103 return res; 104 } 105 106 static int parse_options (char * options, 107 struct btrfs_root *root, 108 char **subvol_name) 109 { 110 char * p; 111 struct btrfs_fs_info *info = NULL; 112 substring_t args[MAX_OPT_ARGS]; 113 114 if (!options) 115 return 1; 116 117 /* 118 * strsep changes the string, duplicate it because parse_options 119 * gets called twice 120 */ 121 options = kstrdup(options, GFP_NOFS); 122 if (!options) 123 return -ENOMEM; 124 125 if (root) 126 info = root->fs_info; 127 128 while ((p = strsep (&options, ",")) != NULL) { 129 int token; 130 if (!*p) 131 continue; 132 133 token = match_token(p, tokens, args); 134 switch (token) { 135 case Opt_subvol: 136 if (subvol_name) { 137 *subvol_name = match_strdup(&args[0]); 138 } 139 break; 140 case Opt_nodatasum: 141 if (info) { 142 printk("btrfs: setting nodatacsum\n"); 143 btrfs_set_opt(info->mount_opt, NODATASUM); 144 } 145 break; 146 case Opt_nodatacow: 147 if (info) { 148 printk("btrfs: setting nodatacow\n"); 149 btrfs_set_opt(info->mount_opt, NODATACOW); 150 btrfs_set_opt(info->mount_opt, NODATASUM); 151 } 152 break; 153 case Opt_ssd: 154 if (info) { 155 printk("btrfs: use ssd allocation scheme\n"); 156 btrfs_set_opt(info->mount_opt, SSD); 157 } 158 break; 159 case Opt_nobarrier: 160 if (info) { 161 printk("btrfs: turning off barriers\n"); 162 btrfs_set_opt(info->mount_opt, NOBARRIER); 163 } 164 break; 165 case Opt_max_extent: 166 if (info) { 167 char *num = match_strdup(&args[0]); 168 if (num) { 169 info->max_extent = 170 btrfs_parse_size(num); 171 kfree(num); 172 173 info->max_extent = max_t(u64, 174 info->max_extent, 175 root->sectorsize); 176 printk("btrfs: max_extent at %Lu\n", 177 info->max_extent); 178 } 179 } 180 break; 181 case Opt_alloc_start: 182 if (info) { 183 char *num = match_strdup(&args[0]); 184 if (num) { 185 info->alloc_start = 186 btrfs_parse_size(num); 187 kfree(num); 188 printk("btrfs: allocations start at " 189 "%Lu\n", info->alloc_start); 190 } 191 } 192 break; 193 default: 194 break; 195 } 196 } 197 kfree(options); 198 return 1; 199 } 200 201 static int btrfs_fill_super(struct super_block * sb, void * data, int silent) 202 { 203 struct inode * inode; 204 struct dentry * root_dentry; 205 struct btrfs_super_block *disk_super; 206 struct btrfs_root *tree_root; 207 struct btrfs_inode *bi; 208 int err; 209 210 sb->s_maxbytes = MAX_LFS_FILESIZE; 211 sb->s_magic = BTRFS_SUPER_MAGIC; 212 sb->s_op = &btrfs_super_ops; 213 sb->s_xattr = btrfs_xattr_handlers; 214 sb->s_time_gran = 1; 215 216 tree_root = open_ctree(sb); 217 218 if (!tree_root || IS_ERR(tree_root)) { 219 printk("btrfs: open_ctree failed\n"); 220 return -EIO; 221 } 222 sb->s_fs_info = tree_root; 223 disk_super = &tree_root->fs_info->super_copy; 224 inode = btrfs_iget_locked(sb, btrfs_super_root_dir(disk_super), 225 tree_root); 226 bi = BTRFS_I(inode); 227 bi->location.objectid = inode->i_ino; 228 bi->location.offset = 0; 229 bi->root = tree_root; 230 231 btrfs_set_key_type(&bi->location, BTRFS_INODE_ITEM_KEY); 232 233 if (!inode) { 234 err = -ENOMEM; 235 goto fail_close; 236 } 237 if (inode->i_state & I_NEW) { 238 btrfs_read_locked_inode(inode); 239 unlock_new_inode(inode); 240 } 241 242 root_dentry = d_alloc_root(inode); 243 if (!root_dentry) { 244 iput(inode); 245 err = -ENOMEM; 246 goto fail_close; 247 } 248 249 parse_options((char *)data, tree_root, NULL); 250 251 /* this does the super kobj at the same time */ 252 err = btrfs_sysfs_add_super(tree_root->fs_info); 253 if (err) 254 goto fail_close; 255 256 sb->s_root = root_dentry; 257 btrfs_transaction_queue_work(tree_root, HZ * 30); 258 return 0; 259 260 fail_close: 261 close_ctree(tree_root); 262 return err; 263 } 264 265 static int btrfs_sync_fs(struct super_block *sb, int wait) 266 { 267 struct btrfs_trans_handle *trans; 268 struct btrfs_root *root; 269 int ret; 270 root = btrfs_sb(sb); 271 272 sb->s_dirt = 0; 273 if (!wait) { 274 filemap_flush(root->fs_info->btree_inode->i_mapping); 275 return 0; 276 } 277 btrfs_clean_old_snapshots(root); 278 mutex_lock(&root->fs_info->fs_mutex); 279 btrfs_defrag_dirty_roots(root->fs_info); 280 trans = btrfs_start_transaction(root, 1); 281 ret = btrfs_commit_transaction(trans, root); 282 sb->s_dirt = 0; 283 mutex_unlock(&root->fs_info->fs_mutex); 284 return ret; 285 } 286 287 static void btrfs_write_super(struct super_block *sb) 288 { 289 sb->s_dirt = 0; 290 } 291 292 /* 293 * This is almost a copy of get_sb_bdev in fs/super.c. 294 * We need the local copy to allow direct mounting of 295 * subvolumes, but this could be easily integrated back 296 * into the generic version. --hch 297 */ 298 299 /* start copy & paste */ 300 static int set_bdev_super(struct super_block *s, void *data) 301 { 302 s->s_bdev = data; 303 s->s_dev = s->s_bdev->bd_dev; 304 return 0; 305 } 306 307 static int test_bdev_super(struct super_block *s, void *data) 308 { 309 return (void *)s->s_bdev == data; 310 } 311 312 int btrfs_get_sb_bdev(struct file_system_type *fs_type, 313 int flags, const char *dev_name, void *data, 314 int (*fill_super)(struct super_block *, void *, int), 315 struct vfsmount *mnt, const char *subvol) 316 { 317 struct block_device *bdev = NULL; 318 struct super_block *s; 319 struct dentry *root; 320 int error = 0; 321 322 bdev = open_bdev_excl(dev_name, flags, fs_type); 323 if (IS_ERR(bdev)) 324 return PTR_ERR(bdev); 325 326 /* 327 * once the super is inserted into the list by sget, s_umount 328 * will protect the lockfs code from trying to start a snapshot 329 * while we are mounting 330 */ 331 down(&bdev->bd_mount_sem); 332 s = sget(fs_type, test_bdev_super, set_bdev_super, bdev); 333 up(&bdev->bd_mount_sem); 334 if (IS_ERR(s)) 335 goto error_s; 336 337 if (s->s_root) { 338 if ((flags ^ s->s_flags) & MS_RDONLY) { 339 up_write(&s->s_umount); 340 deactivate_super(s); 341 error = -EBUSY; 342 goto error_bdev; 343 } 344 345 close_bdev_excl(bdev); 346 } else { 347 char b[BDEVNAME_SIZE]; 348 349 s->s_flags = flags; 350 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id)); 351 sb_set_blocksize(s, block_size(bdev)); 352 error = fill_super(s, data, flags & MS_SILENT ? 1 : 0); 353 if (error) { 354 up_write(&s->s_umount); 355 deactivate_super(s); 356 goto error; 357 } 358 359 s->s_flags |= MS_ACTIVE; 360 } 361 362 if (subvol) { 363 root = lookup_one_len(subvol, s->s_root, strlen(subvol)); 364 if (IS_ERR(root)) { 365 up_write(&s->s_umount); 366 deactivate_super(s); 367 error = PTR_ERR(root); 368 goto error; 369 } 370 if (!root->d_inode) { 371 dput(root); 372 up_write(&s->s_umount); 373 deactivate_super(s); 374 error = -ENXIO; 375 goto error; 376 } 377 } else { 378 root = dget(s->s_root); 379 } 380 381 mnt->mnt_sb = s; 382 mnt->mnt_root = root; 383 return 0; 384 385 error_s: 386 error = PTR_ERR(s); 387 error_bdev: 388 close_bdev_excl(bdev); 389 error: 390 return error; 391 } 392 /* end copy & paste */ 393 394 static int btrfs_get_sb(struct file_system_type *fs_type, 395 int flags, const char *dev_name, void *data, struct vfsmount *mnt) 396 { 397 int ret; 398 char *subvol_name = NULL; 399 400 parse_options((char *)data, NULL, &subvol_name); 401 ret = btrfs_get_sb_bdev(fs_type, flags, dev_name, data, 402 btrfs_fill_super, mnt, 403 subvol_name ? subvol_name : "default"); 404 if (subvol_name) 405 kfree(subvol_name); 406 return ret; 407 } 408 409 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf) 410 { 411 struct btrfs_root *root = btrfs_sb(dentry->d_sb); 412 struct btrfs_super_block *disk_super = &root->fs_info->super_copy; 413 int bits = dentry->d_sb->s_blocksize_bits; 414 415 buf->f_namelen = BTRFS_NAME_LEN; 416 buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits; 417 buf->f_bfree = buf->f_blocks - 418 (btrfs_super_bytes_used(disk_super) >> bits); 419 buf->f_bavail = buf->f_bfree; 420 buf->f_bsize = dentry->d_sb->s_blocksize; 421 buf->f_type = BTRFS_SUPER_MAGIC; 422 return 0; 423 } 424 425 static struct file_system_type btrfs_fs_type = { 426 .owner = THIS_MODULE, 427 .name = "btrfs", 428 .get_sb = btrfs_get_sb, 429 .kill_sb = kill_block_super, 430 .fs_flags = FS_REQUIRES_DEV, 431 }; 432 static void btrfs_write_super_lockfs(struct super_block *sb) 433 { 434 struct btrfs_root *root = btrfs_sb(sb); 435 btrfs_transaction_flush_work(root); 436 } 437 438 static void btrfs_unlockfs(struct super_block *sb) 439 { 440 struct btrfs_root *root = btrfs_sb(sb); 441 btrfs_transaction_queue_work(root, HZ * 30); 442 } 443 444 static struct super_operations btrfs_super_ops = { 445 .delete_inode = btrfs_delete_inode, 446 .put_inode = btrfs_put_inode, 447 .put_super = btrfs_put_super, 448 .read_inode = btrfs_read_locked_inode, 449 .write_super = btrfs_write_super, 450 .sync_fs = btrfs_sync_fs, 451 .write_inode = btrfs_write_inode, 452 .dirty_inode = btrfs_dirty_inode, 453 .alloc_inode = btrfs_alloc_inode, 454 .destroy_inode = btrfs_destroy_inode, 455 .statfs = btrfs_statfs, 456 .write_super_lockfs = btrfs_write_super_lockfs, 457 .unlockfs = btrfs_unlockfs, 458 }; 459 static int __init init_btrfs_fs(void) 460 { 461 int err; 462 463 err = btrfs_init_sysfs(); 464 if (err) 465 return err; 466 467 btrfs_init_transaction_sys(); 468 err = btrfs_init_cachep(); 469 if (err) 470 goto free_transaction_sys; 471 err = extent_map_init(); 472 if (err) 473 goto free_cachep; 474 475 err = register_filesystem(&btrfs_fs_type); 476 if (err) 477 goto free_extent_map; 478 return 0; 479 480 free_extent_map: 481 extent_map_exit(); 482 free_cachep: 483 btrfs_destroy_cachep(); 484 free_transaction_sys: 485 btrfs_exit_transaction_sys(); 486 btrfs_exit_sysfs(); 487 return err; 488 } 489 490 static void __exit exit_btrfs_fs(void) 491 { 492 btrfs_exit_transaction_sys(); 493 btrfs_destroy_cachep(); 494 extent_map_exit(); 495 unregister_filesystem(&btrfs_fs_type); 496 btrfs_exit_sysfs(); 497 } 498 499 module_init(init_btrfs_fs) 500 module_exit(exit_btrfs_fs) 501 502 MODULE_LICENSE("GPL"); 503