fs/btrfs/super.c

   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/seq_file.h>
  28 #include <linux/string.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 <linux/miscdevice.h>
  40 #include <linux/magic.h>
  41 #include <linux/slab.h>
  42 #include <linux/cleancache.h>
  43 #include <linux/ratelimit.h>
  44 #include "compat.h"
  45 #include "delayed-inode.h"
  46 #include "ctree.h"
  47 #include "disk-io.h"
  48 #include "transaction.h"
  49 #include "btrfs_inode.h"
  50 #include "ioctl.h"
  51 #include "print-tree.h"
  52 #include "xattr.h"
  53 #include "volumes.h"
  54 #include "version.h"
  55 #include "export.h"
  56 #include "compression.h"
  57 #include "rcu-string.h"
  58
  59 #define CREATE_TRACE_POINTS
  60 #include <trace/events/btrfs.h>
  61
  62 static const struct super_operations btrfs_super_ops;
  63 static struct file_system_type btrfs_fs_type;
  64
  65 static const char *btrfs_decode_error(struct btrfs_fs_info *fs_info, int errno,
  66                                       char nbuf[16])
  67 {
  68         char *errstr = NULL;
  69
  70         switch (errno) {
  71         case -EIO:
  72                 errstr = "IO failure";
  73                 break;
  74         case -ENOMEM:
  75                 errstr = "Out of memory";
  76                 break;
  77         case -EROFS:
  78                 errstr = "Readonly filesystem";
  79                 break;
  80         case -EEXIST:
  81                 errstr = "Object already exists";
  82                 break;
  83         default:
  84                 if (nbuf) {
  85                         if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
  86                                 errstr = nbuf;
  87                 }
  88                 break;
  89         }
  90
  91         return errstr;
  92 }
  93
  94 static void __save_error_info(struct btrfs_fs_info *fs_info)
  95 {
  96         /*
  97          * today we only save the error info into ram.  Long term we'll
  98          * also send it down to the disk
  99          */
 100         fs_info->fs_state = BTRFS_SUPER_FLAG_ERROR;
 101 }
 102
 103 static void save_error_info(struct btrfs_fs_info *fs_info)
 104 {
 105         __save_error_info(fs_info);
 106 }
 107
 108 /* btrfs handle error by forcing the filesystem readonly */
 109 static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
 110 {
 111         struct super_block *sb = fs_info->sb;
 112
 113         if (sb->s_flags & MS_RDONLY)
 114                 return;
 115
 116         if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
 117                 sb->s_flags |= MS_RDONLY;
 118                 printk(KERN_INFO "btrfs is forced readonly\n");
 119                 __btrfs_scrub_cancel(fs_info);
 120 //              WARN_ON(1);
 121         }
 122 }
 123
 124 #ifdef CONFIG_PRINTK
 125 /*
 126  * __btrfs_std_error decodes expected errors from the caller and
 127  * invokes the approciate error response.
 128  */
 129 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
 130                        unsigned int line, int errno, const char *fmt, ...)
 131 {
 132         struct super_block *sb = fs_info->sb;
 133         char nbuf[16];
 134         const char *errstr;
 135         va_list args;
 136         va_start(args, fmt);
 137
 138         /*
 139          * Special case: if the error is EROFS, and we're already
 140          * under MS_RDONLY, then it is safe here.
 141          */
 142         if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
 143                 return;
 144
 145         errstr = btrfs_decode_error(fs_info, errno, nbuf);
 146         if (fmt) {
 147                 struct va_format vaf = {
 148                         .fmt = fmt,
 149                         .va = &args,
 150                 };
 151
 152                 printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s (%pV)\n",
 153                         sb->s_id, function, line, errstr, &vaf);
 154         } else {
 155                 printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n",
 156                         sb->s_id, function, line, errstr);
 157         }
 158
 159         /* Don't go through full error handling during mount */
 160         if (sb->s_flags & MS_BORN) {
 161                 save_error_info(fs_info);
 162                 btrfs_handle_error(fs_info);
 163         }
 164         va_end(args);
 165 }
 166
 167 static const char * const logtypes[] = {
 168         "emergency",
 169         "alert",
 170         "critical",
 171         "error",
 172         "warning",
 173         "notice",
 174         "info",
 175         "debug",
 176 };
 177
 178 void btrfs_printk(struct btrfs_fs_info *fs_info, const char *fmt, ...)
 179 {
 180         struct super_block *sb = fs_info->sb;
 181         char lvl[4];
 182         struct va_format vaf;
 183         va_list args;
 184         const char *type = logtypes[4];
 185         int kern_level;
 186
 187         va_start(args, fmt);
 188
 189         kern_level = printk_get_level(fmt);
 190         if (kern_level) {
 191                 size_t size = printk_skip_level(fmt) - fmt;
 192                 memcpy(lvl, fmt,  size);
 193                 lvl[size] = '\0';
 194                 fmt += size;
 195                 type = logtypes[kern_level - '0'];
 196         } else
 197                 *lvl = '\0';
 198
 199         vaf.fmt = fmt;
 200         vaf.va = &args;
 201
 202         printk("%sBTRFS %s (device %s): %pV", lvl, type, sb->s_id, &vaf);
 203
 204         va_end(args);
 205 }
 206
 207 #else
 208
 209 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
 210                        unsigned int line, int errno, const char *fmt, ...)
 211 {
 212         struct super_block *sb = fs_info->sb;
 213
 214         /*
 215          * Special case: if the error is EROFS, and we're already
 216          * under MS_RDONLY, then it is safe here.
 217          */
 218         if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
 219                 return;
 220
 221         /* Don't go through full error handling during mount */
 222         if (sb->s_flags & MS_BORN) {
 223                 save_error_info(fs_info);
 224                 btrfs_handle_error(fs_info);
 225         }
 226 }
 227 #endif
 228
 229 /*
 230  * We only mark the transaction aborted and then set the file system read-only.
 231  * This will prevent new transactions from starting or trying to join this
 232  * one.
 233  *
 234  * This means that error recovery at the call site is limited to freeing
 235  * any local memory allocations and passing the error code up without
 236  * further cleanup. The transaction should complete as it normally would
 237  * in the call path but will return -EIO.
 238  *
 239  * We'll complete the cleanup in btrfs_end_transaction and
 240  * btrfs_commit_transaction.
 241  */
 242 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
 243                                struct btrfs_root *root, const char *function,
 244                                unsigned int line, int errno)
 245 {
 246         WARN_ONCE(1, KERN_DEBUG "btrfs: Transaction aborted");
 247         trans->aborted = errno;
 248         /* Nothing used. The other threads that have joined this
 249          * transaction may be able to continue. */
 250         if (!trans->blocks_used) {
 251                 char nbuf[16];
 252                 const char *errstr;
 253
 254                 errstr = btrfs_decode_error(root->fs_info, errno, nbuf);
 255                 btrfs_printk(root->fs_info,
 256                              "%s:%d: Aborting unused transaction(%s).\n",
 257                              function, line, errstr);
 258                 return;
 259         }
 260         trans->transaction->aborted = errno;
 261         __btrfs_std_error(root->fs_info, function, line, errno, NULL);
 262 }
 263 /*
 264  * __btrfs_panic decodes unexpected, fatal errors from the caller,
 265  * issues an alert, and either panics or BUGs, depending on mount options.
 266  */
 267 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
 268                    unsigned int line, int errno, const char *fmt, ...)
 269 {
 270         char nbuf[16];
 271         char *s_id = "<unknown>";
 272         const char *errstr;
 273         struct va_format vaf = { .fmt = fmt };
 274         va_list args;
 275
 276         if (fs_info)
 277                 s_id = fs_info->sb->s_id;
 278
 279         va_start(args, fmt);
 280         vaf.va = &args;
 281
 282         errstr = btrfs_decode_error(fs_info, errno, nbuf);
 283         if (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR)
 284                 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (%s)\n",
 285                         s_id, function, line, &vaf, errstr);
 286
 287         printk(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (%s)\n",
 288                s_id, function, line, &vaf, errstr);
 289         va_end(args);
 290         /* Caller calls BUG() */
 291 }
 292
 293 static void btrfs_put_super(struct super_block *sb)
 294 {
 295         (void)close_ctree(btrfs_sb(sb)->tree_root);
 296         /* FIXME: need to fix VFS to return error? */
 297         /* AV: return it _where_?  ->put_super() can be triggered by any number
 298          * of async events, up to and including delivery of SIGKILL to the
 299          * last process that kept it busy.  Or segfault in the aforementioned
 300          * process...  Whom would you report that to?
 301          */
 302 }
 303
 304 enum {
 305         Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
 306         Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
 307         Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
 308         Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
 309         Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
 310         Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
 311         Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache,
 312         Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
 313         Opt_check_integrity, Opt_check_integrity_including_extent_data,
 314         Opt_check_integrity_print_mask, Opt_fatal_errors,
 315         Opt_err,
 316 };
 317
 318 static match_table_t tokens = {
 319         {Opt_degraded, "degraded"},
 320         {Opt_subvol, "subvol=%s"},
 321         {Opt_subvolid, "subvolid=%d"},
 322         {Opt_device, "device=%s"},
 323         {Opt_nodatasum, "nodatasum"},
 324         {Opt_nodatacow, "nodatacow"},
 325         {Opt_nobarrier, "nobarrier"},
 326         {Opt_max_inline, "max_inline=%s"},
 327         {Opt_alloc_start, "alloc_start=%s"},
 328         {Opt_thread_pool, "thread_pool=%d"},
 329         {Opt_compress, "compress"},
 330         {Opt_compress_type, "compress=%s"},
 331         {Opt_compress_force, "compress-force"},
 332         {Opt_compress_force_type, "compress-force=%s"},
 333         {Opt_ssd, "ssd"},
 334         {Opt_ssd_spread, "ssd_spread"},
 335         {Opt_nossd, "nossd"},
 336         {Opt_noacl, "noacl"},
 337         {Opt_notreelog, "notreelog"},
 338         {Opt_flushoncommit, "flushoncommit"},
 339         {Opt_ratio, "metadata_ratio=%d"},
 340         {Opt_discard, "discard"},
 341         {Opt_space_cache, "space_cache"},
 342         {Opt_clear_cache, "clear_cache"},
 343         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 344         {Opt_enospc_debug, "enospc_debug"},
 345         {Opt_subvolrootid, "subvolrootid=%d"},
 346         {Opt_defrag, "autodefrag"},
 347         {Opt_inode_cache, "inode_cache"},
 348         {Opt_no_space_cache, "nospace_cache"},
 349         {Opt_recovery, "recovery"},
 350         {Opt_skip_balance, "skip_balance"},
 351         {Opt_check_integrity, "check_int"},
 352         {Opt_check_integrity_including_extent_data, "check_int_data"},
 353         {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
 354         {Opt_fatal_errors, "fatal_errors=%s"},
 355         {Opt_err, NULL},
 356 };
 357
 358 /*
 359  * Regular mount options parser.  Everything that is needed only when
 360  * reading in a new superblock is parsed here.
 361  * XXX JDM: This needs to be cleaned up for remount.
 362  */
 363 int btrfs_parse_options(struct btrfs_root *root, char *options)
 364 {
 365         struct btrfs_fs_info *info = root->fs_info;
 366         substring_t args[MAX_OPT_ARGS];
 367         char *p, *num, *orig = NULL;
 368         u64 cache_gen;
 369         int intarg;
 370         int ret = 0;
 371         char *compress_type;
 372         bool compress_force = false;
 373
 374         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
 375         if (cache_gen)
 376                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 377
 378         if (!options)
 379                 goto out;
 380
 381         /*
 382          * strsep changes the string, duplicate it because parse_options
 383          * gets called twice
 384          */
 385         options = kstrdup(options, GFP_NOFS);
 386         if (!options)
 387                 return -ENOMEM;
 388
 389         orig = options;
 390
 391         while ((p = strsep(&options, ",")) != NULL) {
 392                 int token;
 393                 if (!*p)
 394                         continue;
 395
 396                 token = match_token(p, tokens, args);
 397                 switch (token) {
 398                 case Opt_degraded:
 399                         printk(KERN_INFO "btrfs: allowing degraded mounts\n");
 400                         btrfs_set_opt(info->mount_opt, DEGRADED);
 401                         break;
 402                 case Opt_subvol:
 403                 case Opt_subvolid:
 404                 case Opt_subvolrootid:
 405                 case Opt_device:
 406                         /*
 407                          * These are parsed by btrfs_parse_early_options
 408                          * and can be happily ignored here.
 409                          */
 410                         break;
 411                 case Opt_nodatasum:
 412                         printk(KERN_INFO "btrfs: setting nodatasum\n");
 413                         btrfs_set_opt(info->mount_opt, NODATASUM);
 414                         break;
 415                 case Opt_nodatacow:
 416                         printk(KERN_INFO "btrfs: setting nodatacow\n");
 417                         btrfs_set_opt(info->mount_opt, NODATACOW);
 418                         btrfs_set_opt(info->mount_opt, NODATASUM);
 419                         break;
 420                 case Opt_compress_force:
 421                 case Opt_compress_force_type:
 422                         compress_force = true;
 423                 case Opt_compress:
 424                 case Opt_compress_type:
 425                         if (token == Opt_compress ||
 426                             token == Opt_compress_force ||
 427                             strcmp(args[0].from, "zlib") == 0) {
 428                                 compress_type = "zlib";
 429                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
 430                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 431                         } else if (strcmp(args[0].from, "lzo") == 0) {
 432                                 compress_type = "lzo";
 433                                 info->compress_type = BTRFS_COMPRESS_LZO;
 434                                 btrfs_set_opt(info->mount_opt, COMPRESS);
 435                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
 436                         } else if (strncmp(args[0].from, "no", 2) == 0) {
 437                                 compress_type = "no";
 438                                 info->compress_type = BTRFS_COMPRESS_NONE;
 439                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
 440                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 441                                 compress_force = false;
 442                         } else {
 443                                 ret = -EINVAL;
 444                                 goto out;
 445                         }
 446
 447                         if (compress_force) {
 448                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 449                                 pr_info("btrfs: force %s compression\n",
 450                                         compress_type);
 451                         } else
 452                                 pr_info("btrfs: use %s compression\n",
 453                                         compress_type);
 454                         break;
 455                 case Opt_ssd:
 456                         printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
 457                         btrfs_set_opt(info->mount_opt, SSD);
 458                         break;
 459                 case Opt_ssd_spread:
 460                         printk(KERN_INFO "btrfs: use spread ssd "
 461                                "allocation scheme\n");
 462                         btrfs_set_opt(info->mount_opt, SSD);
 463                         btrfs_set_opt(info->mount_opt, SSD_SPREAD);
 464                         break;
 465                 case Opt_nossd:
 466                         printk(KERN_INFO "btrfs: not using ssd allocation "
 467                                "scheme\n");
 468                         btrfs_set_opt(info->mount_opt, NOSSD);
 469                         btrfs_clear_opt(info->mount_opt, SSD);
 470                         btrfs_clear_opt(info->mount_opt, SSD_SPREAD);
 471                         break;
 472                 case Opt_nobarrier:
 473                         printk(KERN_INFO "btrfs: turning off barriers\n");
 474                         btrfs_set_opt(info->mount_opt, NOBARRIER);
 475                         break;
 476                 case Opt_thread_pool:
 477                         intarg = 0;
 478                         match_int(&args[0], &intarg);
 479                         if (intarg)
 480                                 info->thread_pool_size = intarg;
 481                         break;
 482                 case Opt_max_inline:
 483                         num = match_strdup(&args[0]);
 484                         if (num) {
 485                                 info->max_inline = memparse(num, NULL);
 486                                 kfree(num);
 487
 488                                 if (info->max_inline) {
 489                                         info->max_inline = max_t(u64,
 490                                                 info->max_inline,
 491                                                 root->sectorsize);
 492                                 }
 493                                 printk(KERN_INFO "btrfs: max_inline at %llu\n",
 494                                         (unsigned long long)info->max_inline);
 495                         }
 496                         break;
 497                 case Opt_alloc_start:
 498                         num = match_strdup(&args[0]);
 499                         if (num) {
 500                                 info->alloc_start = memparse(num, NULL);
 501                                 kfree(num);
 502                                 printk(KERN_INFO
 503                                         "btrfs: allocations start at %llu\n",
 504                                         (unsigned long long)info->alloc_start);
 505                         }
 506                         break;
 507                 case Opt_noacl:
 508                         root->fs_info->sb->s_flags &= ~MS_POSIXACL;
 509                         break;
 510                 case Opt_notreelog:
 511                         printk(KERN_INFO "btrfs: disabling tree log\n");
 512                         btrfs_set_opt(info->mount_opt, NOTREELOG);
 513                         break;
 514                 case Opt_flushoncommit:
 515                         printk(KERN_INFO "btrfs: turning on flush-on-commit\n");
 516                         btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT);
 517                         break;
 518                 case Opt_ratio:
 519                         intarg = 0;
 520                         match_int(&args[0], &intarg);
 521                         if (intarg) {
 522                                 info->metadata_ratio = intarg;
 523                                 printk(KERN_INFO "btrfs: metadata ratio %d\n",
 524                                        info->metadata_ratio);
 525                         }
 526                         break;
 527                 case Opt_discard:
 528                         btrfs_set_opt(info->mount_opt, DISCARD);
 529                         break;
 530                 case Opt_space_cache:
 531                         btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 532                         break;
 533                 case Opt_no_space_cache:
 534                         printk(KERN_INFO "btrfs: disabling disk space caching\n");
 535                         btrfs_clear_opt(info->mount_opt, SPACE_CACHE);
 536                         break;
 537                 case Opt_inode_cache:
 538                         printk(KERN_INFO "btrfs: enabling inode map caching\n");
 539                         btrfs_set_opt(info->mount_opt, INODE_MAP_CACHE);
 540                         break;
 541                 case Opt_clear_cache:
 542                         printk(KERN_INFO "btrfs: force clearing of disk cache\n");
 543                         btrfs_set_opt(info->mount_opt, CLEAR_CACHE);
 544                         break;
 545                 case Opt_user_subvol_rm_allowed:
 546                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 547                         break;
 548                 case Opt_enospc_debug:
 549                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 550                         break;
 551                 case Opt_defrag:
 552                         printk(KERN_INFO "btrfs: enabling auto defrag");
 553                         btrfs_set_opt(info->mount_opt, AUTO_DEFRAG);
 554                         break;
 555                 case Opt_recovery:
 556                         printk(KERN_INFO "btrfs: enabling auto recovery");
 557                         btrfs_set_opt(info->mount_opt, RECOVERY);
 558                         break;
 559                 case Opt_skip_balance:
 560                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
 561                         break;
 562 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 563                 case Opt_check_integrity_including_extent_data:
 564                         printk(KERN_INFO "btrfs: enabling check integrity"
 565                                " including extent data\n");
 566                         btrfs_set_opt(info->mount_opt,
 567                                       CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
 568                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 569                         break;
 570                 case Opt_check_integrity:
 571                         printk(KERN_INFO "btrfs: enabling check integrity\n");
 572                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 573                         break;
 574                 case Opt_check_integrity_print_mask:
 575                         intarg = 0;
 576                         match_int(&args[0], &intarg);
 577                         if (intarg) {
 578                                 info->check_integrity_print_mask = intarg;
 579                                 printk(KERN_INFO "btrfs:"
 580                                        " check_integrity_print_mask 0x%x\n",
 581                                        info->check_integrity_print_mask);
 582                         }
 583                         break;
 584 #else
 585                 case Opt_check_integrity_including_extent_data:
 586                 case Opt_check_integrity:
 587                 case Opt_check_integrity_print_mask:
 588                         printk(KERN_ERR "btrfs: support for check_integrity*"
 589                                " not compiled in!\n");
 590                         ret = -EINVAL;
 591                         goto out;
 592 #endif
 593                 case Opt_fatal_errors:
 594                         if (strcmp(args[0].from, "panic") == 0)
 595                                 btrfs_set_opt(info->mount_opt,
 596                                               PANIC_ON_FATAL_ERROR);
 597                         else if (strcmp(args[0].from, "bug") == 0)
 598                                 btrfs_clear_opt(info->mount_opt,
 599                                               PANIC_ON_FATAL_ERROR);
 600                         else {
 601                                 ret = -EINVAL;
 602                                 goto out;
 603                         }
 604                         break;
 605                 case Opt_err:
 606                         printk(KERN_INFO "btrfs: unrecognized mount option "
 607                                "'%s'\n", p);
 608                         ret = -EINVAL;
 609                         goto out;
 610                 default:
 611                         break;
 612                 }
 613         }
 614 out:
 615         if (!ret && btrfs_test_opt(root, SPACE_CACHE))
 616                 printk(KERN_INFO "btrfs: disk space caching is enabled\n");
 617         kfree(orig);
 618         return ret;
 619 }
 620
 621 /*
 622  * Parse mount options that are required early in the mount process.
 623  *
 624  * All other options will be parsed on much later in the mount process and
 625  * only when we need to allocate a new super block.
 626  */
 627 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 628                 void *holder, char **subvol_name, u64 *subvol_objectid,
 629                 u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices)
 630 {
 631         substring_t args[MAX_OPT_ARGS];
 632         char *device_name, *opts, *orig, *p;
 633         int error = 0;
 634         int intarg;
 635
 636         if (!options)
 637                 return 0;
 638
 639         /*
 640          * strsep changes the string, duplicate it because parse_options
 641          * gets called twice
 642          */
 643         opts = kstrdup(options, GFP_KERNEL);
 644         if (!opts)
 645                 return -ENOMEM;
 646         orig = opts;
 647
 648         while ((p = strsep(&opts, ",")) != NULL) {
 649                 int token;
 650                 if (!*p)
 651                         continue;
 652
 653                 token = match_token(p, tokens, args);
 654                 switch (token) {
 655                 case Opt_subvol:
 656                         kfree(*subvol_name);
 657                         *subvol_name = match_strdup(&args[0]);
 658                         break;
 659                 case Opt_subvolid:
 660                         intarg = 0;
 661                         error = match_int(&args[0], &intarg);
 662                         if (!error) {
 663                                 /* we want the original fs_tree */
 664                                 if (!intarg)
 665                                         *subvol_objectid =
 666                                                 BTRFS_FS_TREE_OBJECTID;
 667                                 else
 668                                         *subvol_objectid = intarg;
 669                         }
 670                         break;
 671                 case Opt_subvolrootid:
 672                         intarg = 0;
 673                         error = match_int(&args[0], &intarg);
 674                         if (!error) {
 675                                 /* we want the original fs_tree */
 676                                 if (!intarg)
 677                                         *subvol_rootid =
 678                                                 BTRFS_FS_TREE_OBJECTID;
 679                                 else
 680                                         *subvol_rootid = intarg;
 681                         }
 682                         break;
 683                 case Opt_device:
 684                         device_name = match_strdup(&args[0]);
 685                         if (!device_name) {
 686                                 error = -ENOMEM;
 687                                 goto out;
 688                         }
 689                         error = btrfs_scan_one_device(device_name,
 690                                         flags, holder, fs_devices);
 691                         kfree(device_name);
 692                         if (error)
 693                                 goto out;
 694                         break;
 695                 default:
 696                         break;
 697                 }
 698         }
 699
 700 out:
 701         kfree(orig);
 702         return error;
 703 }
 704
 705 static struct dentry *get_default_root(struct super_block *sb,
 706                                        u64 subvol_objectid)
 707 {
 708         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
 709         struct btrfs_root *root = fs_info->tree_root;
 710         struct btrfs_root *new_root;
 711         struct btrfs_dir_item *di;
 712         struct btrfs_path *path;
 713         struct btrfs_key location;
 714         struct inode *inode;
 715         u64 dir_id;
 716         int new = 0;
 717
 718         /*
 719          * We have a specific subvol we want to mount, just setup location and
 720          * go look up the root.
 721          */
 722         if (subvol_objectid) {
 723                 location.objectid = subvol_objectid;
 724                 location.type = BTRFS_ROOT_ITEM_KEY;
 725                 location.offset = (u64)-1;
 726                 goto find_root;
 727         }
 728
 729         path = btrfs_alloc_path();
 730         if (!path)
 731                 return ERR_PTR(-ENOMEM);
 732         path->leave_spinning = 1;
 733
 734         /*
 735          * Find the "default" dir item which points to the root item that we
 736          * will mount by default if we haven't been given a specific subvolume
 737          * to mount.
 738          */
 739         dir_id = btrfs_super_root_dir(fs_info->super_copy);
 740         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
 741         if (IS_ERR(di)) {
 742                 btrfs_free_path(path);
 743                 return ERR_CAST(di);
 744         }
 745         if (!di) {
 746                 /*
 747                  * Ok the default dir item isn't there.  This is weird since
 748                  * it's always been there, but don't freak out, just try and
 749                  * mount to root most subvolume.
 750                  */
 751                 btrfs_free_path(path);
 752                 dir_id = BTRFS_FIRST_FREE_OBJECTID;
 753                 new_root = fs_info->fs_root;
 754                 goto setup_root;
 755         }
 756
 757         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
 758         btrfs_free_path(path);
 759
 760 find_root:
 761         new_root = btrfs_read_fs_root_no_name(fs_info, &location);
 762         if (IS_ERR(new_root))
 763                 return ERR_CAST(new_root);
 764
 765         if (btrfs_root_refs(&new_root->root_item) == 0)
 766                 return ERR_PTR(-ENOENT);
 767
 768         dir_id = btrfs_root_dirid(&new_root->root_item);
 769 setup_root:
 770         location.objectid = dir_id;
 771         location.type = BTRFS_INODE_ITEM_KEY;
 772         location.offset = 0;
 773
 774         inode = btrfs_iget(sb, &location, new_root, &new);
 775         if (IS_ERR(inode))
 776                 return ERR_CAST(inode);
 777
 778         /*
 779          * If we're just mounting the root most subvol put the inode and return
 780          * a reference to the dentry.  We will have already gotten a reference
 781          * to the inode in btrfs_fill_super so we're good to go.
 782          */
 783         if (!new && sb->s_root->d_inode == inode) {
 784                 iput(inode);
 785                 return dget(sb->s_root);
 786         }
 787
 788         return d_obtain_alias(inode);
 789 }
 790
 791 static int btrfs_fill_super(struct super_block *sb,
 792                             struct btrfs_fs_devices *fs_devices,
 793                             void *data, int silent)
 794 {
 795         struct inode *inode;
 796         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
 797         struct btrfs_key key;
 798         int err;
 799
 800         sb->s_maxbytes = MAX_LFS_FILESIZE;
 801         sb->s_magic = BTRFS_SUPER_MAGIC;
 802         sb->s_op = &btrfs_super_ops;
 803         sb->s_d_op = &btrfs_dentry_operations;
 804         sb->s_export_op = &btrfs_export_ops;
 805         sb->s_xattr = btrfs_xattr_handlers;
 806         sb->s_time_gran = 1;
 807 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 808         sb->s_flags |= MS_POSIXACL;
 809 #endif
 810         sb->s_flags |= MS_I_VERSION;
 811         err = open_ctree(sb, fs_devices, (char *)data);
 812         if (err) {
 813                 printk("btrfs: open_ctree failed\n");
 814                 return err;
 815         }
 816
 817         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
 818         key.type = BTRFS_INODE_ITEM_KEY;
 819         key.offset = 0;
 820         inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
 821         if (IS_ERR(inode)) {
 822                 err = PTR_ERR(inode);
 823                 goto fail_close;
 824         }
 825
 826         sb->s_root = d_make_root(inode);
 827         if (!sb->s_root) {
 828                 err = -ENOMEM;
 829                 goto fail_close;
 830         }
 831
 832         save_mount_options(sb, data);
 833         cleancache_init_fs(sb);
 834         sb->s_flags |= MS_ACTIVE;
 835         return 0;
 836
 837 fail_close:
 838         close_ctree(fs_info->tree_root);
 839         return err;
 840 }
 841
 842 int btrfs_sync_fs(struct super_block *sb, int wait)
 843 {
 844         struct btrfs_trans_handle *trans;
 845         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
 846         struct btrfs_root *root = fs_info->tree_root;
 847
 848         trace_btrfs_sync_fs(wait);
 849
 850         if (!wait) {
 851                 filemap_flush(fs_info->btree_inode->i_mapping);
 852                 return 0;
 853         }
 854
 855         btrfs_wait_ordered_extents(root, 0, 0);
 856
 857         spin_lock(&fs_info->trans_lock);
 858         if (!fs_info->running_transaction) {
 859                 spin_unlock(&fs_info->trans_lock);
 860                 return 0;
 861         }
 862         spin_unlock(&fs_info->trans_lock);
 863
 864         trans = btrfs_join_transaction(root);
 865         if (IS_ERR(trans))
 866                 return PTR_ERR(trans);
 867         return btrfs_commit_transaction(trans, root);
 868 }
 869
 870 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
 871 {
 872         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
 873         struct btrfs_root *root = info->tree_root;
 874         char *compress_type;
 875
 876         if (btrfs_test_opt(root, DEGRADED))
 877                 seq_puts(seq, ",degraded");
 878         if (btrfs_test_opt(root, NODATASUM))
 879                 seq_puts(seq, ",nodatasum");
 880         if (btrfs_test_opt(root, NODATACOW))
 881                 seq_puts(seq, ",nodatacow");
 882         if (btrfs_test_opt(root, NOBARRIER))
 883                 seq_puts(seq, ",nobarrier");
 884         if (info->max_inline != 8192 * 1024)
 885                 seq_printf(seq, ",max_inline=%llu",
 886                            (unsigned long long)info->max_inline);
 887         if (info->alloc_start != 0)
 888                 seq_printf(seq, ",alloc_start=%llu",
 889                            (unsigned long long)info->alloc_start);
 890         if (info->thread_pool_size !=  min_t(unsigned long,
 891                                              num_online_cpus() + 2, 8))
 892                 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
 893         if (btrfs_test_opt(root, COMPRESS)) {
 894                 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
 895                         compress_type = "zlib";
 896                 else
 897                         compress_type = "lzo";
 898                 if (btrfs_test_opt(root, FORCE_COMPRESS))
 899                         seq_printf(seq, ",compress-force=%s", compress_type);
 900                 else
 901                         seq_printf(seq, ",compress=%s", compress_type);
 902         }
 903         if (btrfs_test_opt(root, NOSSD))
 904                 seq_puts(seq, ",nossd");
 905         if (btrfs_test_opt(root, SSD_SPREAD))
 906                 seq_puts(seq, ",ssd_spread");
 907         else if (btrfs_test_opt(root, SSD))
 908                 seq_puts(seq, ",ssd");
 909         if (btrfs_test_opt(root, NOTREELOG))
 910                 seq_puts(seq, ",notreelog");
 911         if (btrfs_test_opt(root, FLUSHONCOMMIT))
 912                 seq_puts(seq, ",flushoncommit");
 913         if (btrfs_test_opt(root, DISCARD))
 914                 seq_puts(seq, ",discard");
 915         if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
 916                 seq_puts(seq, ",noacl");
 917         if (btrfs_test_opt(root, SPACE_CACHE))
 918                 seq_puts(seq, ",space_cache");
 919         else
 920                 seq_puts(seq, ",nospace_cache");
 921         if (btrfs_test_opt(root, CLEAR_CACHE))
 922                 seq_puts(seq, ",clear_cache");
 923         if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
 924                 seq_puts(seq, ",user_subvol_rm_allowed");
 925         if (btrfs_test_opt(root, ENOSPC_DEBUG))
 926                 seq_puts(seq, ",enospc_debug");
 927         if (btrfs_test_opt(root, AUTO_DEFRAG))
 928                 seq_puts(seq, ",autodefrag");
 929         if (btrfs_test_opt(root, INODE_MAP_CACHE))
 930                 seq_puts(seq, ",inode_cache");
 931         if (btrfs_test_opt(root, SKIP_BALANCE))
 932                 seq_puts(seq, ",skip_balance");
 933         if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
 934                 seq_puts(seq, ",fatal_errors=panic");
 935         return 0;
 936 }
 937
 938 static int btrfs_test_super(struct super_block *s, void *data)
 939 {
 940         struct btrfs_fs_info *p = data;
 941         struct btrfs_fs_info *fs_info = btrfs_sb(s);
 942
 943         return fs_info->fs_devices == p->fs_devices;
 944 }
 945
 946 static int btrfs_set_super(struct super_block *s, void *data)
 947 {
 948         int err = set_anon_super(s, data);
 949         if (!err)
 950                 s->s_fs_info = data;
 951         return err;
 952 }
 953
 954 /*
 955  * subvolumes are identified by ino 256
 956  */
 957 static inline int is_subvolume_inode(struct inode *inode)
 958 {
 959         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
 960                 return 1;
 961         return 0;
 962 }
 963
 964 /*
 965  * This will strip out the subvol=%s argument for an argument string and add
 966  * subvolid=0 to make sure we get the actual tree root for path walking to the
 967  * subvol we want.
 968  */
 969 static char *setup_root_args(char *args)
 970 {
 971         unsigned len = strlen(args) + 2 + 1;
 972         char *src, *dst, *buf;
 973
 974         /*
 975          * We need the same args as before, but with this substitution:
 976          * s!subvol=[^,]+!subvolid=0!
 977          *
 978          * Since the replacement string is up to 2 bytes longer than the
 979          * original, allocate strlen(args) + 2 + 1 bytes.
 980          */
 981
 982         src = strstr(args, "subvol=");
 983         /* This shouldn't happen, but just in case.. */
 984         if (!src)
 985                 return NULL;
 986
 987         buf = dst = kmalloc(len, GFP_NOFS);
 988         if (!buf)
 989                 return NULL;
 990
 991         /*
 992          * If the subvol= arg is not at the start of the string,
 993          * copy whatever precedes it into buf.
 994          */
 995         if (src != args) {
 996                 *src++ = '\0';
 997                 strcpy(buf, args);
 998                 dst += strlen(args);
 999         }
1000
1001         strcpy(dst, "subvolid=0");
1002         dst += strlen("subvolid=0");
1003
1004         /*
1005          * If there is a "," after the original subvol=... string,
1006          * copy that suffix into our buffer.  Otherwise, we're done.
1007          */
1008         src = strchr(src, ',');
1009         if (src)
1010                 strcpy(dst, src);
1011
1012         return buf;
1013 }
1014
1015 static struct dentry *mount_subvol(const char *subvol_name, int flags,
1016                                    const char *device_name, char *data)
1017 {
1018         struct dentry *root;
1019         struct vfsmount *mnt;
1020         char *newargs;
1021
1022         newargs = setup_root_args(data);
1023         if (!newargs)
1024                 return ERR_PTR(-ENOMEM);
1025         mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
1026                              newargs);
1027         kfree(newargs);
1028         if (IS_ERR(mnt))
1029                 return ERR_CAST(mnt);
1030
1031         root = mount_subtree(mnt, subvol_name);
1032
1033         if (!IS_ERR(root) && !is_subvolume_inode(root->d_inode)) {
1034                 struct super_block *s = root->d_sb;
1035                 dput(root);
1036                 root = ERR_PTR(-EINVAL);
1037                 deactivate_locked_super(s);
1038                 printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n",
1039                                 subvol_name);
1040         }
1041
1042         return root;
1043 }
1044
1045 /*
1046  * Find a superblock for the given device / mount point.
1047  *
1048  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
1049  *        for multiple device setup.  Make sure to keep it in sync.
1050  */
1051 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1052                 const char *device_name, void *data)
1053 {
1054         struct block_device *bdev = NULL;
1055         struct super_block *s;
1056         struct dentry *root;
1057         struct btrfs_fs_devices *fs_devices = NULL;
1058         struct btrfs_fs_info *fs_info = NULL;
1059         fmode_t mode = FMODE_READ;
1060         char *subvol_name = NULL;
1061         u64 subvol_objectid = 0;
1062         u64 subvol_rootid = 0;
1063         int error = 0;
1064
1065         if (!(flags & MS_RDONLY))
1066                 mode |= FMODE_WRITE;
1067
1068         error = btrfs_parse_early_options(data, mode, fs_type,
1069                                           &subvol_name, &subvol_objectid,
1070                                           &subvol_rootid, &fs_devices);
1071         if (error) {
1072                 kfree(subvol_name);
1073                 return ERR_PTR(error);
1074         }
1075
1076         if (subvol_name) {
1077                 root = mount_subvol(subvol_name, flags, device_name, data);
1078                 kfree(subvol_name);
1079                 return root;
1080         }
1081
1082         error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1083         if (error)
1084                 return ERR_PTR(error);
1085
1086         /*
1087          * Setup a dummy root and fs_info for test/set super.  This is because
1088          * we don't actually fill this stuff out until open_ctree, but we need
1089          * it for searching for existing supers, so this lets us do that and
1090          * then open_ctree will properly initialize everything later.
1091          */
1092         fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1093         if (!fs_info)
1094                 return ERR_PTR(-ENOMEM);
1095
1096         fs_info->fs_devices = fs_devices;
1097
1098         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1099         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1100         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1101                 error = -ENOMEM;
1102                 goto error_fs_info;
1103         }
1104
1105         error = btrfs_open_devices(fs_devices, mode, fs_type);
1106         if (error)
1107                 goto error_fs_info;
1108
1109         if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1110                 error = -EACCES;
1111                 goto error_close_devices;
1112         }
1113
1114         bdev = fs_devices->latest_bdev;
1115         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1116                  fs_info);
1117         if (IS_ERR(s)) {
1118                 error = PTR_ERR(s);
1119                 goto error_close_devices;
1120         }
1121
1122         if (s->s_root) {
1123                 btrfs_close_devices(fs_devices);
1124                 free_fs_info(fs_info);
1125                 if ((flags ^ s->s_flags) & MS_RDONLY)
1126                         error = -EBUSY;
1127         } else {
1128                 char b[BDEVNAME_SIZE];
1129
1130                 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
1131                 btrfs_sb(s)->bdev_holder = fs_type;
1132                 error = btrfs_fill_super(s, fs_devices, data,
1133                                          flags & MS_SILENT ? 1 : 0);
1134         }
1135
1136         root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error);
1137         if (IS_ERR(root))
1138                 deactivate_locked_super(s);
1139
1140         return root;
1141
1142 error_close_devices:
1143         btrfs_close_devices(fs_devices);
1144 error_fs_info:
1145         free_fs_info(fs_info);
1146         return ERR_PTR(error);
1147 }
1148
1149 static void btrfs_set_max_workers(struct btrfs_workers *workers, int new_limit)
1150 {
1151         spin_lock_irq(&workers->lock);
1152         workers->max_workers = new_limit;
1153         spin_unlock_irq(&workers->lock);
1154 }
1155
1156 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1157                                      int new_pool_size, int old_pool_size)
1158 {
1159         if (new_pool_size == old_pool_size)
1160                 return;
1161
1162         fs_info->thread_pool_size = new_pool_size;
1163
1164         printk(KERN_INFO "btrfs: resize thread pool %d -> %d\n",
1165                old_pool_size, new_pool_size);
1166
1167         btrfs_set_max_workers(&fs_info->generic_worker, new_pool_size);
1168         btrfs_set_max_workers(&fs_info->workers, new_pool_size);
1169         btrfs_set_max_workers(&fs_info->delalloc_workers, new_pool_size);
1170         btrfs_set_max_workers(&fs_info->submit_workers, new_pool_size);
1171         btrfs_set_max_workers(&fs_info->caching_workers, new_pool_size);
1172         btrfs_set_max_workers(&fs_info->fixup_workers, new_pool_size);
1173         btrfs_set_max_workers(&fs_info->endio_workers, new_pool_size);
1174         btrfs_set_max_workers(&fs_info->endio_meta_workers, new_pool_size);
1175         btrfs_set_max_workers(&fs_info->endio_meta_write_workers, new_pool_size);
1176         btrfs_set_max_workers(&fs_info->endio_write_workers, new_pool_size);
1177         btrfs_set_max_workers(&fs_info->endio_freespace_worker, new_pool_size);
1178         btrfs_set_max_workers(&fs_info->delayed_workers, new_pool_size);
1179         btrfs_set_max_workers(&fs_info->readahead_workers, new_pool_size);
1180         btrfs_set_max_workers(&fs_info->scrub_workers, new_pool_size);
1181 }
1182
1183 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1184 {
1185         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1186         struct btrfs_root *root = fs_info->tree_root;
1187         unsigned old_flags = sb->s_flags;
1188         unsigned long old_opts = fs_info->mount_opt;
1189         unsigned long old_compress_type = fs_info->compress_type;
1190         u64 old_max_inline = fs_info->max_inline;
1191         u64 old_alloc_start = fs_info->alloc_start;
1192         int old_thread_pool_size = fs_info->thread_pool_size;
1193         unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1194         int ret;
1195
1196         ret = btrfs_parse_options(root, data);
1197         if (ret) {
1198                 ret = -EINVAL;
1199                 goto restore;
1200         }
1201
1202         btrfs_resize_thread_pool(fs_info,
1203                 fs_info->thread_pool_size, old_thread_pool_size);
1204
1205         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1206                 return 0;
1207
1208         if (*flags & MS_RDONLY) {
1209                 sb->s_flags |= MS_RDONLY;
1210
1211                 ret = btrfs_commit_super(root);
1212                 if (ret)
1213                         goto restore;
1214         } else {
1215                 if (fs_info->fs_devices->rw_devices == 0) {
1216                         ret = -EACCES;
1217                         goto restore;
1218                 }
1219
1220                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1221                         ret = -EINVAL;
1222                         goto restore;
1223                 }
1224
1225                 ret = btrfs_cleanup_fs_roots(fs_info);
1226                 if (ret)
1227                         goto restore;
1228
1229                 /* recover relocation */
1230                 ret = btrfs_recover_relocation(root);
1231                 if (ret)
1232                         goto restore;
1233
1234                 ret = btrfs_resume_balance_async(fs_info);
1235                 if (ret)
1236                         goto restore;
1237
1238                 sb->s_flags &= ~MS_RDONLY;
1239         }
1240
1241         return 0;
1242
1243 restore:
1244         /* We've hit an error - don't reset MS_RDONLY */
1245         if (sb->s_flags & MS_RDONLY)
1246                 old_flags |= MS_RDONLY;
1247         sb->s_flags = old_flags;
1248         fs_info->mount_opt = old_opts;
1249         fs_info->compress_type = old_compress_type;
1250         fs_info->max_inline = old_max_inline;
1251         fs_info->alloc_start = old_alloc_start;
1252         btrfs_resize_thread_pool(fs_info,
1253                 old_thread_pool_size, fs_info->thread_pool_size);
1254         fs_info->metadata_ratio = old_metadata_ratio;
1255         return ret;
1256 }
1257
1258 /* Used to sort the devices by max_avail(descending sort) */
1259 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1260                                        const void *dev_info2)
1261 {
1262         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1263             ((struct btrfs_device_info *)dev_info2)->max_avail)
1264                 return -1;
1265         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1266                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1267                 return 1;
1268         else
1269         return 0;
1270 }
1271
1272 /*
1273  * sort the devices by max_avail, in which max free extent size of each device
1274  * is stored.(Descending Sort)
1275  */
1276 static inline void btrfs_descending_sort_devices(
1277                                         struct btrfs_device_info *devices,
1278                                         size_t nr_devices)
1279 {
1280         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1281              btrfs_cmp_device_free_bytes, NULL);
1282 }
1283
1284 /*
1285  * The helper to calc the free space on the devices that can be used to store
1286  * file data.
1287  */
1288 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1289 {
1290         struct btrfs_fs_info *fs_info = root->fs_info;
1291         struct btrfs_device_info *devices_info;
1292         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1293         struct btrfs_device *device;
1294         u64 skip_space;
1295         u64 type;
1296         u64 avail_space;
1297         u64 used_space;
1298         u64 min_stripe_size;
1299         int min_stripes = 1, num_stripes = 1;
1300         int i = 0, nr_devices;
1301         int ret;
1302
1303         nr_devices = fs_info->fs_devices->open_devices;
1304         BUG_ON(!nr_devices);
1305
1306         devices_info = kmalloc(sizeof(*devices_info) * nr_devices,
1307                                GFP_NOFS);
1308         if (!devices_info)
1309                 return -ENOMEM;
1310
1311         /* calc min stripe number for data space alloction */
1312         type = btrfs_get_alloc_profile(root, 1);
1313         if (type & BTRFS_BLOCK_GROUP_RAID0) {
1314                 min_stripes = 2;
1315                 num_stripes = nr_devices;
1316         } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1317                 min_stripes = 2;
1318                 num_stripes = 2;
1319         } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1320                 min_stripes = 4;
1321                 num_stripes = 4;
1322         }
1323
1324         if (type & BTRFS_BLOCK_GROUP_DUP)
1325                 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1326         else
1327                 min_stripe_size = BTRFS_STRIPE_LEN;
1328
1329         list_for_each_entry(device, &fs_devices->devices, dev_list) {
1330                 if (!device->in_fs_metadata || !device->bdev)
1331                         continue;
1332
1333                 avail_space = device->total_bytes - device->bytes_used;
1334
1335                 /* align with stripe_len */
1336                 do_div(avail_space, BTRFS_STRIPE_LEN);
1337                 avail_space *= BTRFS_STRIPE_LEN;
1338
1339                 /*
1340                  * In order to avoid overwritting the superblock on the drive,
1341                  * btrfs starts at an offset of at least 1MB when doing chunk
1342                  * allocation.
1343                  */
1344                 skip_space = 1024 * 1024;
1345
1346                 /* user can set the offset in fs_info->alloc_start. */
1347                 if (fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1348                     device->total_bytes)
1349                         skip_space = max(fs_info->alloc_start, skip_space);
1350
1351                 /*
1352                  * btrfs can not use the free space in [0, skip_space - 1],
1353                  * we must subtract it from the total. In order to implement
1354                  * it, we account the used space in this range first.
1355                  */
1356                 ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1,
1357                                                      &used_space);
1358                 if (ret) {
1359                         kfree(devices_info);
1360                         return ret;
1361                 }
1362
1363                 /* calc the free space in [0, skip_space - 1] */
1364                 skip_space -= used_space;
1365
1366                 /*
1367                  * we can use the free space in [0, skip_space - 1], subtract
1368                  * it from the total.
1369                  */
1370                 if (avail_space && avail_space >= skip_space)
1371                         avail_space -= skip_space;
1372                 else
1373                         avail_space = 0;
1374
1375                 if (avail_space < min_stripe_size)
1376                         continue;
1377
1378                 devices_info[i].dev = device;
1379                 devices_info[i].max_avail = avail_space;
1380
1381                 i++;
1382         }
1383
1384         nr_devices = i;
1385
1386         btrfs_descending_sort_devices(devices_info, nr_devices);
1387
1388         i = nr_devices - 1;
1389         avail_space = 0;
1390         while (nr_devices >= min_stripes) {
1391                 if (num_stripes > nr_devices)
1392                         num_stripes = nr_devices;
1393
1394                 if (devices_info[i].max_avail >= min_stripe_size) {
1395                         int j;
1396                         u64 alloc_size;
1397
1398                         avail_space += devices_info[i].max_avail * num_stripes;
1399                         alloc_size = devices_info[i].max_avail;
1400                         for (j = i + 1 - num_stripes; j <= i; j++)
1401                                 devices_info[j].max_avail -= alloc_size;
1402                 }
1403                 i--;
1404                 nr_devices--;
1405         }
1406
1407         kfree(devices_info);
1408         *free_bytes = avail_space;
1409         return 0;
1410 }
1411
1412 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1413 {
1414         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
1415         struct btrfs_super_block *disk_super = fs_info->super_copy;
1416         struct list_head *head = &fs_info->space_info;
1417         struct btrfs_space_info *found;
1418         u64 total_used = 0;
1419         u64 total_free_data = 0;
1420         int bits = dentry->d_sb->s_blocksize_bits;
1421         __be32 *fsid = (__be32 *)fs_info->fsid;
1422         int ret;
1423
1424         /* holding chunk_muext to avoid allocating new chunks */
1425         mutex_lock(&fs_info->chunk_mutex);
1426         rcu_read_lock();
1427         list_for_each_entry_rcu(found, head, list) {
1428                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1429                         total_free_data += found->disk_total - found->disk_used;
1430                         total_free_data -=
1431                                 btrfs_account_ro_block_groups_free_space(found);
1432                 }
1433
1434                 total_used += found->disk_used;
1435         }
1436         rcu_read_unlock();
1437
1438         buf->f_namelen = BTRFS_NAME_LEN;
1439         buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
1440         buf->f_bfree = buf->f_blocks - (total_used >> bits);
1441         buf->f_bsize = dentry->d_sb->s_blocksize;
1442         buf->f_type = BTRFS_SUPER_MAGIC;
1443         buf->f_bavail = total_free_data;
1444         ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
1445         if (ret) {
1446                 mutex_unlock(&fs_info->chunk_mutex);
1447                 return ret;
1448         }
1449         buf->f_bavail += total_free_data;
1450         buf->f_bavail = buf->f_bavail >> bits;
1451         mutex_unlock(&fs_info->chunk_mutex);
1452
1453         /* We treat it as constant endianness (it doesn't matter _which_)
1454            because we want the fsid to come out the same whether mounted
1455            on a big-endian or little-endian host */
1456         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1457         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1458         /* Mask in the root object ID too, to disambiguate subvols */
1459         buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
1460         buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
1461
1462         return 0;
1463 }
1464
1465 static void btrfs_kill_super(struct super_block *sb)
1466 {
1467         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1468         kill_anon_super(sb);
1469         free_fs_info(fs_info);
1470 }
1471
1472 static struct file_system_type btrfs_fs_type = {
1473         .owner          = THIS_MODULE,
1474         .name           = "btrfs",
1475         .mount          = btrfs_mount,
1476         .kill_sb        = btrfs_kill_super,
1477         .fs_flags       = FS_REQUIRES_DEV,
1478 };
1479
1480 /*
1481  * used by btrfsctl to scan devices when no FS is mounted
1482  */
1483 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
1484                                 unsigned long arg)
1485 {
1486         struct btrfs_ioctl_vol_args *vol;
1487         struct btrfs_fs_devices *fs_devices;
1488         int ret = -ENOTTY;
1489
1490         if (!capable(CAP_SYS_ADMIN))
1491                 return -EPERM;
1492
1493         vol = memdup_user((void __user *)arg, sizeof(*vol));
1494         if (IS_ERR(vol))
1495                 return PTR_ERR(vol);
1496
1497         switch (cmd) {
1498         case BTRFS_IOC_SCAN_DEV:
1499                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1500                                             &btrfs_fs_type, &fs_devices);
1501                 break;
1502         case BTRFS_IOC_DEVICES_READY:
1503                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1504                                             &btrfs_fs_type, &fs_devices);
1505                 if (ret)
1506                         break;
1507                 ret = !(fs_devices->num_devices == fs_devices->total_devices);
1508                 break;
1509         }
1510
1511         kfree(vol);
1512         return ret;
1513 }
1514
1515 static int btrfs_freeze(struct super_block *sb)
1516 {
1517         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1518         mutex_lock(&fs_info->transaction_kthread_mutex);
1519         mutex_lock(&fs_info->cleaner_mutex);
1520         return 0;
1521 }
1522
1523 static int btrfs_unfreeze(struct super_block *sb)
1524 {
1525         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1526         mutex_unlock(&fs_info->cleaner_mutex);
1527         mutex_unlock(&fs_info->transaction_kthread_mutex);
1528         return 0;
1529 }
1530
1531 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
1532 {
1533         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
1534         struct btrfs_fs_devices *cur_devices;
1535         struct btrfs_device *dev, *first_dev = NULL;
1536         struct list_head *head;
1537         struct rcu_string *name;
1538
1539         mutex_lock(&fs_info->fs_devices->device_list_mutex);
1540         cur_devices = fs_info->fs_devices;
1541         while (cur_devices) {
1542                 head = &cur_devices->devices;
1543                 list_for_each_entry(dev, head, dev_list) {
1544                         if (dev->missing)
1545                                 continue;
1546                         if (!first_dev || dev->devid < first_dev->devid)
1547                                 first_dev = dev;
1548                 }
1549                 cur_devices = cur_devices->seed;
1550         }
1551
1552         if (first_dev) {
1553                 rcu_read_lock();
1554                 name = rcu_dereference(first_dev->name);
1555                 seq_escape(m, name->str, " \t\n\\");
1556                 rcu_read_unlock();
1557         } else {
1558                 WARN_ON(1);
1559         }
1560         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1561         return 0;
1562 }
1563
1564 static const struct super_operations btrfs_super_ops = {
1565         .drop_inode     = btrfs_drop_inode,
1566         .evict_inode    = btrfs_evict_inode,
1567         .put_super      = btrfs_put_super,
1568         .sync_fs        = btrfs_sync_fs,
1569         .show_options   = btrfs_show_options,
1570         .show_devname   = btrfs_show_devname,
1571         .write_inode    = btrfs_write_inode,
1572         .alloc_inode    = btrfs_alloc_inode,
1573         .destroy_inode  = btrfs_destroy_inode,
1574         .statfs         = btrfs_statfs,
1575         .remount_fs     = btrfs_remount,
1576         .freeze_fs      = btrfs_freeze,
1577         .unfreeze_fs    = btrfs_unfreeze,
1578 };
1579
1580 static const struct file_operations btrfs_ctl_fops = {
1581         .unlocked_ioctl  = btrfs_control_ioctl,
1582         .compat_ioctl = btrfs_control_ioctl,
1583         .owner   = THIS_MODULE,
1584         .llseek = noop_llseek,
1585 };
1586
1587 static struct miscdevice btrfs_misc = {
1588         .minor          = BTRFS_MINOR,
1589         .name           = "btrfs-control",
1590         .fops           = &btrfs_ctl_fops
1591 };
1592
1593 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
1594 MODULE_ALIAS("devname:btrfs-control");
1595
1596 static int btrfs_interface_init(void)
1597 {
1598         return misc_register(&btrfs_misc);
1599 }
1600
1601 static void btrfs_interface_exit(void)
1602 {
1603         if (misc_deregister(&btrfs_misc) < 0)
1604                 printk(KERN_INFO "misc_deregister failed for control device");
1605 }
1606
1607 static int __init init_btrfs_fs(void)
1608 {
1609         int err;
1610
1611         err = btrfs_init_sysfs();
1612         if (err)
1613                 return err;
1614
1615         btrfs_init_compress();
1616
1617         err = btrfs_init_cachep();
1618         if (err)
1619                 goto free_compress;
1620
1621         err = extent_io_init();
1622         if (err)
1623                 goto free_cachep;
1624
1625         err = extent_map_init();
1626         if (err)
1627                 goto free_extent_io;
1628
1629         err = ordered_data_init();
1630         if (err)
1631                 goto free_extent_map;
1632
1633         err = btrfs_delayed_inode_init();
1634         if (err)
1635                 goto free_ordered_data;
1636
1637         err = btrfs_interface_init();
1638         if (err)
1639                 goto free_delayed_inode;
1640
1641         err = register_filesystem(&btrfs_fs_type);
1642         if (err)
1643                 goto unregister_ioctl;
1644
1645         btrfs_init_lockdep();
1646
1647         printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
1648         return 0;
1649
1650 unregister_ioctl:
1651         btrfs_interface_exit();
1652 free_delayed_inode:
1653         btrfs_delayed_inode_exit();
1654 free_ordered_data:
1655         ordered_data_exit();
1656 free_extent_map:
1657         extent_map_exit();
1658 free_extent_io:
1659         extent_io_exit();
1660 free_cachep:
1661         btrfs_destroy_cachep();
1662 free_compress:
1663         btrfs_exit_compress();
1664         btrfs_exit_sysfs();
1665         return err;
1666 }
1667
1668 static void __exit exit_btrfs_fs(void)
1669 {
1670         btrfs_destroy_cachep();
1671         btrfs_delayed_inode_exit();
1672         ordered_data_exit();
1673         extent_map_exit();
1674         extent_io_exit();
1675         btrfs_interface_exit();
1676         unregister_filesystem(&btrfs_fs_type);
1677         btrfs_exit_sysfs();
1678         btrfs_cleanup_fs_uuids();
1679         btrfs_exit_compress();
1680 }
1681
1682 module_init(init_btrfs_fs)
1683 module_exit(exit_btrfs_fs)
1684
1685 MODULE_LICENSE("GPL");