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 <linux/btrfs.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 "print-tree.h"
  51#include "hash.h"
  52#include "props.h"
  53#include "xattr.h"
  54#include "volumes.h"
  55#include "export.h"
  56#include "compression.h"
  57#include "rcu-string.h"
  58#include "dev-replace.h"
  59#include "free-space-cache.h"
  60#include "backref.h"
 
 
 
  61#include "tests/btrfs-tests.h"
  62
 
  63#include "qgroup.h"
  64#define CREATE_TRACE_POINTS
  65#include <trace/events/btrfs.h>
  66
  67static const struct super_operations btrfs_super_ops;
 
 
 
 
 
 
 
 
 
  68static struct file_system_type btrfs_fs_type;
 
  69
  70static int btrfs_remount(struct super_block *sb, int *flags, char *data);
  71
  72const char *btrfs_decode_error(int errno)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  73{
  74	char *errstr = "unknown";
  75
  76	switch (errno) {
  77	case -EIO:
 
 
 
  78		errstr = "IO failure";
  79		break;
  80	case -ENOMEM:
  81		errstr = "Out of memory";
  82		break;
  83	case -EROFS:
  84		errstr = "Readonly filesystem";
  85		break;
  86	case -EEXIST:
  87		errstr = "Object already exists";
  88		break;
  89	case -ENOSPC:
  90		errstr = "No space left";
  91		break;
  92	case -ENOENT:
  93		errstr = "No such entry";
 
 
 
 
 
 
 
 
 
  94		break;
  95	}
  96
  97	return errstr;
  98}
  99
 100static void save_error_info(struct btrfs_fs_info *fs_info)
 101{
 102	/*
 103	 * today we only save the error info into ram.  Long term we'll
 104	 * also send it down to the disk
 105	 */
 106	set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
 107}
 108
 109/* btrfs handle error by forcing the filesystem readonly */
 110static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
 111{
 112	struct super_block *sb = fs_info->sb;
 113
 114	if (sb->s_flags & MS_RDONLY)
 115		return;
 116
 117	if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
 118		sb->s_flags |= MS_RDONLY;
 119		btrfs_info(fs_info, "forced readonly");
 120		/*
 121		 * Note that a running device replace operation is not
 122		 * canceled here although there is no way to update
 123		 * the progress. It would add the risk of a deadlock,
 124		 * therefore the canceling is ommited. The only penalty
 125		 * is that some I/O remains active until the procedure
 126		 * completes. The next time when the filesystem is
 127		 * mounted writeable again, the device replace
 128		 * operation continues.
 129		 */
 130	}
 131}
 132
 133/*
 134 * __btrfs_std_error decodes expected errors from the caller and
 135 * invokes the approciate error response.
 136 */
 137__cold
 138void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
 139		       unsigned int line, int errno, const char *fmt, ...)
 140{
 141	struct super_block *sb = fs_info->sb;
 142#ifdef CONFIG_PRINTK
 143	const char *errstr;
 144#endif
 145
 146	/*
 147	 * Special case: if the error is EROFS, and we're already
 148	 * under MS_RDONLY, then it is safe here.
 149	 */
 150	if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
 151  		return;
 152
 153#ifdef CONFIG_PRINTK
 154	errstr = btrfs_decode_error(errno);
 155	if (fmt) {
 156		struct va_format vaf;
 157		va_list args;
 158
 159		va_start(args, fmt);
 160		vaf.fmt = fmt;
 161		vaf.va = &args;
 162
 163		printk(KERN_CRIT
 164			"BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
 165			sb->s_id, function, line, errno, errstr, &vaf);
 166		va_end(args);
 167	} else {
 168		printk(KERN_CRIT "BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
 169			sb->s_id, function, line, errno, errstr);
 170	}
 171#endif
 172
 
 
 
 
 
 
 173	/* Don't go through full error handling during mount */
 174	save_error_info(fs_info);
 175	if (sb->s_flags & MS_BORN)
 176		btrfs_handle_error(fs_info);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 177}
 178
 179#ifdef CONFIG_PRINTK
 180static const char * const logtypes[] = {
 181	"emergency",
 182	"alert",
 183	"critical",
 184	"error",
 185	"warning",
 186	"notice",
 187	"info",
 188	"debug",
 189};
 190
 191void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 192{
 193	struct super_block *sb = fs_info->sb;
 194	char lvl[4];
 195	struct va_format vaf;
 196	va_list args;
 197	const char *type = logtypes[4];
 198	int kern_level;
 
 
 199
 200	va_start(args, fmt);
 201
 202	kern_level = printk_get_level(fmt);
 203	if (kern_level) {
 204		size_t size = printk_skip_level(fmt) - fmt;
 205		memcpy(lvl, fmt,  size);
 206		lvl[size] = '\0';
 
 
 
 
 
 207		fmt += size;
 208		type = logtypes[kern_level - '0'];
 209	} else
 210		*lvl = '\0';
 211
 212	vaf.fmt = fmt;
 213	vaf.va = &args;
 214
 215	printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);
 
 
 
 
 
 
 216
 217	va_end(args);
 218}
 219#endif
 220
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 221/*
 222 * We only mark the transaction aborted and then set the file system read-only.
 223 * This will prevent new transactions from starting or trying to join this
 224 * one.
 225 *
 226 * This means that error recovery at the call site is limited to freeing
 227 * any local memory allocations and passing the error code up without
 228 * further cleanup. The transaction should complete as it normally would
 229 * in the call path but will return -EIO.
 230 *
 231 * We'll complete the cleanup in btrfs_end_transaction and
 232 * btrfs_commit_transaction.
 233 */
 234__cold
 235void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
 236			       struct btrfs_root *root, const char *function,
 237			       unsigned int line, int errno)
 238{
 239	trans->aborted = errno;
 240	/* Nothing used. The other threads that have joined this
 241	 * transaction may be able to continue. */
 242	if (!trans->blocks_used && list_empty(&trans->new_bgs)) {
 243		const char *errstr;
 244
 245		errstr = btrfs_decode_error(errno);
 246		btrfs_warn(root->fs_info,
 247		           "%s:%d: Aborting unused transaction(%s).",
 248		           function, line, errstr);
 249		return;
 250	}
 251	ACCESS_ONCE(trans->transaction->aborted) = errno;
 252	/* Wake up anybody who may be waiting on this transaction */
 253	wake_up(&root->fs_info->transaction_wait);
 254	wake_up(&root->fs_info->transaction_blocked_wait);
 255	__btrfs_std_error(root->fs_info, function, line, errno, NULL);
 256}
 257/*
 258 * __btrfs_panic decodes unexpected, fatal errors from the caller,
 259 * issues an alert, and either panics or BUGs, depending on mount options.
 260 */
 261__cold
 262void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
 263		   unsigned int line, int errno, const char *fmt, ...)
 264{
 265	char *s_id = "<unknown>";
 266	const char *errstr;
 267	struct va_format vaf = { .fmt = fmt };
 268	va_list args;
 269
 270	if (fs_info)
 271		s_id = fs_info->sb->s_id;
 272
 273	va_start(args, fmt);
 274	vaf.va = &args;
 275
 276	errstr = btrfs_decode_error(errno);
 277	if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
 278		panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
 279			s_id, function, line, &vaf, errno, errstr);
 280
 281	btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
 282		   function, line, &vaf, errno, errstr);
 283	va_end(args);
 284	/* Caller calls BUG() */
 285}
 286
 287static void btrfs_put_super(struct super_block *sb)
 288{
 289	close_ctree(btrfs_sb(sb)->tree_root);
 290}
 291
 292enum {
 293	Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
 294	Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
 295	Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
 296	Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
 297	Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
 298	Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
 299	Opt_user_subvol_rm_allowed, Opt_enospc_debug, Opt_subvolrootid,
 300	Opt_defrag, Opt_inode_cache, Opt_no_space_cache, Opt_recovery,
 301	Opt_skip_balance, Opt_check_integrity,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 302	Opt_check_integrity_including_extent_data,
 303	Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
 304	Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
 305	Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
 306	Opt_datasum, Opt_treelog, Opt_noinode_cache, Opt_usebackuproot,
 307	Opt_nologreplay, Opt_norecovery,
 308#ifdef CONFIG_BTRFS_DEBUG
 309	Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
 310#endif
 
 
 
 311	Opt_err,
 312};
 313
 314static const match_table_t tokens = {
 315	{Opt_degraded, "degraded"},
 316	{Opt_subvol, "subvol=%s"},
 317	{Opt_subvolid, "subvolid=%s"},
 318	{Opt_device, "device=%s"},
 319	{Opt_nodatasum, "nodatasum"},
 320	{Opt_datasum, "datasum"},
 321	{Opt_nodatacow, "nodatacow"},
 322	{Opt_datacow, "datacow"},
 323	{Opt_nobarrier, "nobarrier"},
 324	{Opt_barrier, "barrier"},
 325	{Opt_max_inline, "max_inline=%s"},
 326	{Opt_alloc_start, "alloc_start=%s"},
 327	{Opt_thread_pool, "thread_pool=%d"},
 328	{Opt_compress, "compress"},
 329	{Opt_compress_type, "compress=%s"},
 330	{Opt_compress_force, "compress-force"},
 331	{Opt_compress_force_type, "compress-force=%s"},
 332	{Opt_ssd, "ssd"},
 333	{Opt_ssd_spread, "ssd_spread"},
 334	{Opt_nossd, "nossd"},
 335	{Opt_acl, "acl"},
 336	{Opt_noacl, "noacl"},
 337	{Opt_notreelog, "notreelog"},
 338	{Opt_treelog, "treelog"},
 339	{Opt_nologreplay, "nologreplay"},
 340	{Opt_norecovery, "norecovery"},
 341	{Opt_flushoncommit, "flushoncommit"},
 342	{Opt_noflushoncommit, "noflushoncommit"},
 343	{Opt_ratio, "metadata_ratio=%d"},
 
 
 
 
 
 
 
 
 
 
 344	{Opt_discard, "discard"},
 
 345	{Opt_nodiscard, "nodiscard"},
 
 
 
 
 346	{Opt_space_cache, "space_cache"},
 
 347	{Opt_space_cache_version, "space_cache=%s"},
 348	{Opt_clear_cache, "clear_cache"},
 
 
 
 
 
 
 
 
 
 349	{Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 350	{Opt_enospc_debug, "enospc_debug"},
 351	{Opt_noenospc_debug, "noenospc_debug"},
 352	{Opt_subvolrootid, "subvolrootid=%d"},
 353	{Opt_defrag, "autodefrag"},
 354	{Opt_nodefrag, "noautodefrag"},
 355	{Opt_inode_cache, "inode_cache"},
 356	{Opt_noinode_cache, "noinode_cache"},
 357	{Opt_no_space_cache, "nospace_cache"},
 358	{Opt_recovery, "recovery"}, /* deprecated */
 359	{Opt_usebackuproot, "usebackuproot"},
 360	{Opt_skip_balance, "skip_balance"},
 
 
 
 
 361	{Opt_check_integrity, "check_int"},
 362	{Opt_check_integrity_including_extent_data, "check_int_data"},
 363	{Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
 364	{Opt_rescan_uuid_tree, "rescan_uuid_tree"},
 365	{Opt_fatal_errors, "fatal_errors=%s"},
 366	{Opt_commit_interval, "commit=%d"},
 367#ifdef CONFIG_BTRFS_DEBUG
 368	{Opt_fragment_data, "fragment=data"},
 369	{Opt_fragment_metadata, "fragment=metadata"},
 370	{Opt_fragment_all, "fragment=all"},
 371#endif
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 372	{Opt_err, NULL},
 373};
 374
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 375/*
 376 * Regular mount options parser.  Everything that is needed only when
 377 * reading in a new superblock is parsed here.
 378 * XXX JDM: This needs to be cleaned up for remount.
 379 */
 380int btrfs_parse_options(struct btrfs_root *root, char *options,
 381			unsigned long new_flags)
 382{
 383	struct btrfs_fs_info *info = root->fs_info;
 384	substring_t args[MAX_OPT_ARGS];
 385	char *p, *num, *orig = NULL;
 386	u64 cache_gen;
 387	int intarg;
 388	int ret = 0;
 389	char *compress_type;
 390	bool compress_force = false;
 391	enum btrfs_compression_type saved_compress_type;
 
 392	bool saved_compress_force;
 393	int no_compress = 0;
 394
 395	cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
 396	if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE))
 397		btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
 398	else if (cache_gen)
 399		btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 
 
 
 
 
 
 
 400
 401	/*
 402	 * Even the options are empty, we still need to do extra check
 403	 * against new flags
 404	 */
 405	if (!options)
 406		goto check;
 407
 408	/*
 409	 * strsep changes the string, duplicate it because parse_options
 410	 * gets called twice
 411	 */
 412	options = kstrdup(options, GFP_NOFS);
 413	if (!options)
 414		return -ENOMEM;
 415
 416	orig = options;
 417
 418	while ((p = strsep(&options, ",")) != NULL) {
 419		int token;
 420		if (!*p)
 421			continue;
 422
 423		token = match_token(p, tokens, args);
 424		switch (token) {
 425		case Opt_degraded:
 426			btrfs_info(root->fs_info, "allowing degraded mounts");
 427			btrfs_set_opt(info->mount_opt, DEGRADED);
 428			break;
 429		case Opt_subvol:
 
 430		case Opt_subvolid:
 431		case Opt_subvolrootid:
 432		case Opt_device:
 433			/*
 434			 * These are parsed by btrfs_parse_early_options
 435			 * and can be happily ignored here.
 436			 */
 437			break;
 438		case Opt_nodatasum:
 439			btrfs_set_and_info(root, NODATASUM,
 440					   "setting nodatasum");
 441			break;
 442		case Opt_datasum:
 443			if (btrfs_test_opt(root, NODATASUM)) {
 444				if (btrfs_test_opt(root, NODATACOW))
 445					btrfs_info(root->fs_info, "setting datasum, datacow enabled");
 
 446				else
 447					btrfs_info(root->fs_info, "setting datasum");
 448			}
 449			btrfs_clear_opt(info->mount_opt, NODATACOW);
 450			btrfs_clear_opt(info->mount_opt, NODATASUM);
 451			break;
 452		case Opt_nodatacow:
 453			if (!btrfs_test_opt(root, NODATACOW)) {
 454				if (!btrfs_test_opt(root, COMPRESS) ||
 455				    !btrfs_test_opt(root, FORCE_COMPRESS)) {
 456					btrfs_info(root->fs_info,
 457						   "setting nodatacow, compression disabled");
 458				} else {
 459					btrfs_info(root->fs_info, "setting nodatacow");
 460				}
 461			}
 462			btrfs_clear_opt(info->mount_opt, COMPRESS);
 463			btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 464			btrfs_set_opt(info->mount_opt, NODATACOW);
 465			btrfs_set_opt(info->mount_opt, NODATASUM);
 466			break;
 467		case Opt_datacow:
 468			btrfs_clear_and_info(root, NODATACOW,
 469					     "setting datacow");
 470			break;
 471		case Opt_compress_force:
 472		case Opt_compress_force_type:
 473			compress_force = true;
 474			/* Fallthrough */
 475		case Opt_compress:
 476		case Opt_compress_type:
 477			saved_compress_type = btrfs_test_opt(root, COMPRESS) ?
 
 478				info->compress_type : BTRFS_COMPRESS_NONE;
 479			saved_compress_force =
 480				btrfs_test_opt(root, FORCE_COMPRESS);
 
 481			if (token == Opt_compress ||
 482			    token == Opt_compress_force ||
 483			    strcmp(args[0].from, "zlib") == 0) {
 484				compress_type = "zlib";
 
 485				info->compress_type = BTRFS_COMPRESS_ZLIB;
 
 
 
 
 
 
 
 
 
 
 
 
 486				btrfs_set_opt(info->mount_opt, COMPRESS);
 487				btrfs_clear_opt(info->mount_opt, NODATACOW);
 488				btrfs_clear_opt(info->mount_opt, NODATASUM);
 489				no_compress = 0;
 490			} else if (strcmp(args[0].from, "lzo") == 0) {
 491				compress_type = "lzo";
 492				info->compress_type = BTRFS_COMPRESS_LZO;
 
 493				btrfs_set_opt(info->mount_opt, COMPRESS);
 494				btrfs_clear_opt(info->mount_opt, NODATACOW);
 495				btrfs_clear_opt(info->mount_opt, NODATASUM);
 496				btrfs_set_fs_incompat(info, COMPRESS_LZO);
 497				no_compress = 0;
 
 
 
 
 
 
 
 
 
 
 
 
 498			} else if (strncmp(args[0].from, "no", 2) == 0) {
 499				compress_type = "no";
 
 
 500				btrfs_clear_opt(info->mount_opt, COMPRESS);
 501				btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 502				compress_force = false;
 503				no_compress++;
 504			} else {
 505				ret = -EINVAL;
 506				goto out;
 507			}
 508
 509			if (compress_force) {
 510				btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
 511			} else {
 512				/*
 513				 * If we remount from compress-force=xxx to
 514				 * compress=xxx, we need clear FORCE_COMPRESS
 515				 * flag, otherwise, there is no way for users
 516				 * to disable forcible compression separately.
 517				 */
 518				btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
 519			}
 520			if ((btrfs_test_opt(root, COMPRESS) &&
 521			     (info->compress_type != saved_compress_type ||
 522			      compress_force != saved_compress_force)) ||
 523			    (!btrfs_test_opt(root, COMPRESS) &&
 524			     no_compress == 1)) {
 525				btrfs_info(root->fs_info,
 526					   "%s %s compression",
 527					   (compress_force) ? "force" : "use",
 528					   compress_type);
 529			}
 530			compress_force = false;
 531			break;
 532		case Opt_ssd:
 533			btrfs_set_and_info(root, SSD,
 534					   "use ssd allocation scheme");
 
 535			break;
 536		case Opt_ssd_spread:
 537			btrfs_set_and_info(root, SSD_SPREAD,
 538					   "use spread ssd allocation scheme");
 539			btrfs_set_opt(info->mount_opt, SSD);
 
 
 540			break;
 541		case Opt_nossd:
 542			btrfs_set_and_info(root, NOSSD,
 543					     "not using ssd allocation scheme");
 544			btrfs_clear_opt(info->mount_opt, SSD);
 
 
 
 
 545			break;
 546		case Opt_barrier:
 547			btrfs_clear_and_info(root, NOBARRIER,
 548					     "turning on barriers");
 549			break;
 550		case Opt_nobarrier:
 551			btrfs_set_and_info(root, NOBARRIER,
 552					   "turning off barriers");
 553			break;
 554		case Opt_thread_pool:
 555			ret = match_int(&args[0], &intarg);
 556			if (ret) {
 557				goto out;
 558			} else if (intarg > 0) {
 559				info->thread_pool_size = intarg;
 560			} else {
 561				ret = -EINVAL;
 562				goto out;
 563			}
 
 564			break;
 565		case Opt_max_inline:
 566			num = match_strdup(&args[0]);
 567			if (num) {
 568				info->max_inline = memparse(num, NULL);
 569				kfree(num);
 570
 571				if (info->max_inline) {
 572					info->max_inline = min_t(u64,
 573						info->max_inline,
 574						root->sectorsize);
 575				}
 576				btrfs_info(root->fs_info, "max_inline at %llu",
 577					info->max_inline);
 578			} else {
 579				ret = -ENOMEM;
 580				goto out;
 581			}
 582			break;
 583		case Opt_alloc_start:
 584			num = match_strdup(&args[0]);
 585			if (num) {
 586				mutex_lock(&info->chunk_mutex);
 587				info->alloc_start = memparse(num, NULL);
 588				mutex_unlock(&info->chunk_mutex);
 589				kfree(num);
 590				btrfs_info(root->fs_info, "allocations start at %llu",
 591					info->alloc_start);
 592			} else {
 593				ret = -ENOMEM;
 594				goto out;
 595			}
 596			break;
 597		case Opt_acl:
 598#ifdef CONFIG_BTRFS_FS_POSIX_ACL
 599			root->fs_info->sb->s_flags |= MS_POSIXACL;
 600			break;
 601#else
 602			btrfs_err(root->fs_info,
 603				"support for ACL not compiled in!");
 604			ret = -EINVAL;
 605			goto out;
 606#endif
 607		case Opt_noacl:
 608			root->fs_info->sb->s_flags &= ~MS_POSIXACL;
 609			break;
 610		case Opt_notreelog:
 611			btrfs_set_and_info(root, NOTREELOG,
 612					   "disabling tree log");
 613			break;
 614		case Opt_treelog:
 615			btrfs_clear_and_info(root, NOTREELOG,
 616					     "enabling tree log");
 617			break;
 618		case Opt_norecovery:
 619		case Opt_nologreplay:
 620			btrfs_set_and_info(root, NOLOGREPLAY,
 
 
 621					   "disabling log replay at mount time");
 622			break;
 623		case Opt_flushoncommit:
 624			btrfs_set_and_info(root, FLUSHONCOMMIT,
 625					   "turning on flush-on-commit");
 626			break;
 627		case Opt_noflushoncommit:
 628			btrfs_clear_and_info(root, FLUSHONCOMMIT,
 629					     "turning off flush-on-commit");
 630			break;
 631		case Opt_ratio:
 632			ret = match_int(&args[0], &intarg);
 633			if (ret) {
 634				goto out;
 635			} else if (intarg >= 0) {
 636				info->metadata_ratio = intarg;
 637				btrfs_info(root->fs_info, "metadata ratio %d",
 638				       info->metadata_ratio);
 
 
 
 
 
 
 
 
 
 
 
 639			} else {
 640				ret = -EINVAL;
 641				goto out;
 642			}
 643			break;
 644		case Opt_discard:
 645			btrfs_set_and_info(root, DISCARD,
 646					   "turning on discard");
 647			break;
 648		case Opt_nodiscard:
 649			btrfs_clear_and_info(root, DISCARD,
 650					     "turning off discard");
 
 
 651			break;
 652		case Opt_space_cache:
 653		case Opt_space_cache_version:
 654			if (token == Opt_space_cache ||
 655			    strcmp(args[0].from, "v1") == 0) {
 656				btrfs_clear_opt(root->fs_info->mount_opt,
 657						FREE_SPACE_TREE);
 658				btrfs_set_and_info(root, SPACE_CACHE,
 659						   "enabling disk space caching");
 660			} else if (strcmp(args[0].from, "v2") == 0) {
 661				btrfs_clear_opt(root->fs_info->mount_opt,
 662						SPACE_CACHE);
 663				btrfs_set_and_info(root, FREE_SPACE_TREE,
 664						   "enabling free space tree");
 665			} else {
 666				ret = -EINVAL;
 667				goto out;
 668			}
 669			break;
 670		case Opt_rescan_uuid_tree:
 671			btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
 672			break;
 673		case Opt_no_space_cache:
 674			if (btrfs_test_opt(root, SPACE_CACHE)) {
 675				btrfs_clear_and_info(root, SPACE_CACHE,
 676						     "disabling disk space caching");
 677			}
 678			if (btrfs_test_opt(root, FREE_SPACE_TREE)) {
 679				btrfs_clear_and_info(root, FREE_SPACE_TREE,
 680						     "disabling free space tree");
 681			}
 682			break;
 683		case Opt_inode_cache:
 684			btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
 685					   "enabling inode map caching");
 686			break;
 687		case Opt_noinode_cache:
 688			btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
 689					     "disabling inode map caching");
 690			break;
 691		case Opt_clear_cache:
 692			btrfs_set_and_info(root, CLEAR_CACHE,
 693					   "force clearing of disk cache");
 694			break;
 695		case Opt_user_subvol_rm_allowed:
 696			btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
 697			break;
 698		case Opt_enospc_debug:
 699			btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
 700			break;
 701		case Opt_noenospc_debug:
 702			btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
 703			break;
 704		case Opt_defrag:
 705			btrfs_set_and_info(root, AUTO_DEFRAG,
 706					   "enabling auto defrag");
 707			break;
 708		case Opt_nodefrag:
 709			btrfs_clear_and_info(root, AUTO_DEFRAG,
 710					     "disabling auto defrag");
 711			break;
 712		case Opt_recovery:
 713			btrfs_warn(root->fs_info,
 714				   "'recovery' is deprecated, use 'usebackuproot' instead");
 715		case Opt_usebackuproot:
 716			btrfs_info(root->fs_info,
 
 
 
 
 717				   "trying to use backup root at mount time");
 718			btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
 719			break;
 720		case Opt_skip_balance:
 721			btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
 722			break;
 723#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 724		case Opt_check_integrity_including_extent_data:
 725			btrfs_info(root->fs_info,
 726				   "enabling check integrity including extent data");
 727			btrfs_set_opt(info->mount_opt,
 728				      CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
 729			btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 730			break;
 731		case Opt_check_integrity:
 732			btrfs_info(root->fs_info, "enabling check integrity");
 733			btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
 734			break;
 735		case Opt_check_integrity_print_mask:
 736			ret = match_int(&args[0], &intarg);
 737			if (ret) {
 738				goto out;
 739			} else if (intarg >= 0) {
 740				info->check_integrity_print_mask = intarg;
 741				btrfs_info(root->fs_info, "check_integrity_print_mask 0x%x",
 742				       info->check_integrity_print_mask);
 743			} else {
 744				ret = -EINVAL;
 745				goto out;
 746			}
 747			break;
 748#else
 749		case Opt_check_integrity_including_extent_data:
 750		case Opt_check_integrity:
 751		case Opt_check_integrity_print_mask:
 752			btrfs_err(root->fs_info,
 753				"support for check_integrity* not compiled in!");
 754			ret = -EINVAL;
 755			goto out;
 756#endif
 757		case Opt_fatal_errors:
 758			if (strcmp(args[0].from, "panic") == 0)
 759				btrfs_set_opt(info->mount_opt,
 760					      PANIC_ON_FATAL_ERROR);
 761			else if (strcmp(args[0].from, "bug") == 0)
 762				btrfs_clear_opt(info->mount_opt,
 763					      PANIC_ON_FATAL_ERROR);
 764			else {
 765				ret = -EINVAL;
 766				goto out;
 767			}
 768			break;
 769		case Opt_commit_interval:
 770			intarg = 0;
 771			ret = match_int(&args[0], &intarg);
 772			if (ret < 0) {
 773				btrfs_err(root->fs_info, "invalid commit interval");
 774				ret = -EINVAL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 775				goto out;
 776			}
 777			if (intarg > 0) {
 778				if (intarg > 300) {
 779					btrfs_warn(root->fs_info, "excessive commit interval %d",
 780							intarg);
 781				}
 782				info->commit_interval = intarg;
 783			} else {
 784				btrfs_info(root->fs_info, "using default commit interval %ds",
 785				    BTRFS_DEFAULT_COMMIT_INTERVAL);
 786				info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
 787			}
 788			break;
 789#ifdef CONFIG_BTRFS_DEBUG
 790		case Opt_fragment_all:
 791			btrfs_info(root->fs_info, "fragmenting all space");
 792			btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 793			btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
 794			break;
 795		case Opt_fragment_metadata:
 796			btrfs_info(root->fs_info, "fragmenting metadata");
 797			btrfs_set_opt(info->mount_opt,
 798				      FRAGMENT_METADATA);
 799			break;
 800		case Opt_fragment_data:
 801			btrfs_info(root->fs_info, "fragmenting data");
 802			btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
 803			break;
 804#endif
 
 
 
 
 
 
 805		case Opt_err:
 806			btrfs_info(root->fs_info, "unrecognized mount option '%s'", p);
 807			ret = -EINVAL;
 808			goto out;
 809		default:
 810			break;
 811		}
 812	}
 813check:
 814	/*
 815	 * Extra check for current option against current flag
 816	 */
 817	if (btrfs_test_opt(root, NOLOGREPLAY) && !(new_flags & MS_RDONLY)) {
 818		btrfs_err(root->fs_info,
 819			  "nologreplay must be used with ro mount option");
 
 820		ret = -EINVAL;
 821	}
 822out:
 823	if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE) &&
 824	    !btrfs_test_opt(root, FREE_SPACE_TREE) &&
 825	    !btrfs_test_opt(root, CLEAR_CACHE)) {
 826		btrfs_err(root->fs_info, "cannot disable free space tree");
 827		ret = -EINVAL;
 828
 829	}
 830	if (!ret && btrfs_test_opt(root, SPACE_CACHE))
 831		btrfs_info(root->fs_info, "disk space caching is enabled");
 832	if (!ret && btrfs_test_opt(root, FREE_SPACE_TREE))
 833		btrfs_info(root->fs_info, "using free space tree");
 834	kfree(orig);
 
 835	return ret;
 836}
 837
 838/*
 839 * Parse mount options that are required early in the mount process.
 840 *
 841 * All other options will be parsed on much later in the mount process and
 842 * only when we need to allocate a new super block.
 843 */
 844static int btrfs_parse_early_options(const char *options, fmode_t flags,
 845		void *holder, char **subvol_name, u64 *subvol_objectid,
 846		struct btrfs_fs_devices **fs_devices)
 847{
 848	substring_t args[MAX_OPT_ARGS];
 849	char *device_name, *opts, *orig, *p;
 850	char *num = NULL;
 851	int error = 0;
 852
 
 
 853	if (!options)
 854		return 0;
 855
 856	/*
 857	 * strsep changes the string, duplicate it because parse_options
 858	 * gets called twice
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 859	 */
 860	opts = kstrdup(options, GFP_KERNEL);
 861	if (!opts)
 862		return -ENOMEM;
 863	orig = opts;
 864
 865	while ((p = strsep(&opts, ",")) != NULL) {
 866		int token;
 867		if (!*p)
 868			continue;
 869
 870		token = match_token(p, tokens, args);
 871		switch (token) {
 872		case Opt_subvol:
 873			kfree(*subvol_name);
 874			*subvol_name = match_strdup(&args[0]);
 875			if (!*subvol_name) {
 876				error = -ENOMEM;
 877				goto out;
 878			}
 879			break;
 880		case Opt_subvolid:
 881			num = match_strdup(&args[0]);
 882			if (num) {
 883				*subvol_objectid = memparse(num, NULL);
 884				kfree(num);
 885				/* we want the original fs_tree */
 886				if (!*subvol_objectid)
 887					*subvol_objectid =
 888						BTRFS_FS_TREE_OBJECTID;
 889			} else {
 890				error = -EINVAL;
 891				goto out;
 892			}
 893			break;
 894		case Opt_subvolrootid:
 895			printk(KERN_WARNING
 896				"BTRFS: 'subvolrootid' mount option is deprecated and has "
 897				"no effect\n");
 898			break;
 899		case Opt_device:
 900			device_name = match_strdup(&args[0]);
 901			if (!device_name) {
 902				error = -ENOMEM;
 903				goto out;
 904			}
 905			error = btrfs_scan_one_device(device_name,
 906					flags, holder, fs_devices);
 907			kfree(device_name);
 908			if (error)
 909				goto out;
 
 
 
 
 
 
 910			break;
 911		default:
 912			break;
 913		}
 914	}
 915
 916out:
 917	kfree(orig);
 918	return error;
 919}
 920
 921static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
 922					   u64 subvol_objectid)
 923{
 924	struct btrfs_root *root = fs_info->tree_root;
 925	struct btrfs_root *fs_root;
 926	struct btrfs_root_ref *root_ref;
 927	struct btrfs_inode_ref *inode_ref;
 928	struct btrfs_key key;
 929	struct btrfs_path *path = NULL;
 930	char *name = NULL, *ptr;
 931	u64 dirid;
 932	int len;
 933	int ret;
 934
 935	path = btrfs_alloc_path();
 936	if (!path) {
 937		ret = -ENOMEM;
 938		goto err;
 939	}
 940	path->leave_spinning = 1;
 941
 942	name = kmalloc(PATH_MAX, GFP_NOFS);
 943	if (!name) {
 944		ret = -ENOMEM;
 945		goto err;
 946	}
 947	ptr = name + PATH_MAX - 1;
 948	ptr[0] = '\0';
 949
 950	/*
 951	 * Walk up the subvolume trees in the tree of tree roots by root
 952	 * backrefs until we hit the top-level subvolume.
 953	 */
 954	while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
 955		key.objectid = subvol_objectid;
 956		key.type = BTRFS_ROOT_BACKREF_KEY;
 957		key.offset = (u64)-1;
 958
 959		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 960		if (ret < 0) {
 961			goto err;
 962		} else if (ret > 0) {
 963			ret = btrfs_previous_item(root, path, subvol_objectid,
 964						  BTRFS_ROOT_BACKREF_KEY);
 965			if (ret < 0) {
 966				goto err;
 967			} else if (ret > 0) {
 968				ret = -ENOENT;
 969				goto err;
 970			}
 971		}
 972
 973		btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 974		subvol_objectid = key.offset;
 975
 976		root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 977					  struct btrfs_root_ref);
 978		len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
 979		ptr -= len + 1;
 980		if (ptr < name) {
 981			ret = -ENAMETOOLONG;
 982			goto err;
 983		}
 984		read_extent_buffer(path->nodes[0], ptr + 1,
 985				   (unsigned long)(root_ref + 1), len);
 986		ptr[0] = '/';
 987		dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
 988		btrfs_release_path(path);
 989
 990		key.objectid = subvol_objectid;
 991		key.type = BTRFS_ROOT_ITEM_KEY;
 992		key.offset = (u64)-1;
 993		fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
 994		if (IS_ERR(fs_root)) {
 995			ret = PTR_ERR(fs_root);
 
 996			goto err;
 997		}
 998
 999		/*
1000		 * Walk up the filesystem tree by inode refs until we hit the
1001		 * root directory.
1002		 */
1003		while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1004			key.objectid = dirid;
1005			key.type = BTRFS_INODE_REF_KEY;
1006			key.offset = (u64)-1;
1007
1008			ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1009			if (ret < 0) {
1010				goto err;
1011			} else if (ret > 0) {
1012				ret = btrfs_previous_item(fs_root, path, dirid,
1013							  BTRFS_INODE_REF_KEY);
1014				if (ret < 0) {
1015					goto err;
1016				} else if (ret > 0) {
1017					ret = -ENOENT;
1018					goto err;
1019				}
1020			}
1021
1022			btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1023			dirid = key.offset;
1024
1025			inode_ref = btrfs_item_ptr(path->nodes[0],
1026						   path->slots[0],
1027						   struct btrfs_inode_ref);
1028			len = btrfs_inode_ref_name_len(path->nodes[0],
1029						       inode_ref);
1030			ptr -= len + 1;
1031			if (ptr < name) {
1032				ret = -ENAMETOOLONG;
1033				goto err;
1034			}
1035			read_extent_buffer(path->nodes[0], ptr + 1,
1036					   (unsigned long)(inode_ref + 1), len);
1037			ptr[0] = '/';
1038			btrfs_release_path(path);
1039		}
 
 
1040	}
1041
1042	btrfs_free_path(path);
1043	if (ptr == name + PATH_MAX - 1) {
1044		name[0] = '/';
1045		name[1] = '\0';
1046	} else {
1047		memmove(name, ptr, name + PATH_MAX - ptr);
1048	}
1049	return name;
1050
1051err:
 
1052	btrfs_free_path(path);
1053	kfree(name);
1054	return ERR_PTR(ret);
1055}
1056
1057static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1058{
1059	struct btrfs_root *root = fs_info->tree_root;
1060	struct btrfs_dir_item *di;
1061	struct btrfs_path *path;
1062	struct btrfs_key location;
1063	u64 dir_id;
1064
1065	path = btrfs_alloc_path();
1066	if (!path)
1067		return -ENOMEM;
1068	path->leave_spinning = 1;
1069
1070	/*
1071	 * Find the "default" dir item which points to the root item that we
1072	 * will mount by default if we haven't been given a specific subvolume
1073	 * to mount.
1074	 */
1075	dir_id = btrfs_super_root_dir(fs_info->super_copy);
1076	di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1077	if (IS_ERR(di)) {
1078		btrfs_free_path(path);
1079		return PTR_ERR(di);
1080	}
1081	if (!di) {
1082		/*
1083		 * Ok the default dir item isn't there.  This is weird since
1084		 * it's always been there, but don't freak out, just try and
1085		 * mount the top-level subvolume.
1086		 */
1087		btrfs_free_path(path);
1088		*objectid = BTRFS_FS_TREE_OBJECTID;
1089		return 0;
1090	}
1091
1092	btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1093	btrfs_free_path(path);
1094	*objectid = location.objectid;
1095	return 0;
1096}
1097
1098static int btrfs_fill_super(struct super_block *sb,
1099			    struct btrfs_fs_devices *fs_devices,
1100			    void *data, int silent)
1101{
1102	struct inode *inode;
1103	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1104	struct btrfs_key key;
1105	int err;
1106
1107	sb->s_maxbytes = MAX_LFS_FILESIZE;
1108	sb->s_magic = BTRFS_SUPER_MAGIC;
1109	sb->s_op = &btrfs_super_ops;
1110	sb->s_d_op = &btrfs_dentry_operations;
1111	sb->s_export_op = &btrfs_export_ops;
1112	sb->s_xattr = btrfs_xattr_handlers;
1113	sb->s_time_gran = 1;
1114#ifdef CONFIG_BTRFS_FS_POSIX_ACL
1115	sb->s_flags |= MS_POSIXACL;
1116#endif
1117	sb->s_flags |= MS_I_VERSION;
1118	sb->s_iflags |= SB_I_CGROUPWB;
 
 
 
 
 
 
 
1119	err = open_ctree(sb, fs_devices, (char *)data);
1120	if (err) {
1121		printk(KERN_ERR "BTRFS: open_ctree failed\n");
1122		return err;
1123	}
1124
1125	key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1126	key.type = BTRFS_INODE_ITEM_KEY;
1127	key.offset = 0;
1128	inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1129	if (IS_ERR(inode)) {
1130		err = PTR_ERR(inode);
1131		goto fail_close;
1132	}
1133
1134	sb->s_root = d_make_root(inode);
1135	if (!sb->s_root) {
1136		err = -ENOMEM;
1137		goto fail_close;
1138	}
1139
1140	save_mount_options(sb, data);
1141	cleancache_init_fs(sb);
1142	sb->s_flags |= MS_ACTIVE;
1143	return 0;
1144
1145fail_close:
1146	close_ctree(fs_info->tree_root);
1147	return err;
1148}
1149
1150int btrfs_sync_fs(struct super_block *sb, int wait)
1151{
1152	struct btrfs_trans_handle *trans;
1153	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1154	struct btrfs_root *root = fs_info->tree_root;
1155
1156	trace_btrfs_sync_fs(wait);
1157
1158	if (!wait) {
1159		filemap_flush(fs_info->btree_inode->i_mapping);
1160		return 0;
1161	}
1162
1163	btrfs_wait_ordered_roots(fs_info, -1);
1164
1165	trans = btrfs_attach_transaction_barrier(root);
1166	if (IS_ERR(trans)) {
1167		/* no transaction, don't bother */
1168		if (PTR_ERR(trans) == -ENOENT) {
1169			/*
1170			 * Exit unless we have some pending changes
1171			 * that need to go through commit
1172			 */
1173			if (fs_info->pending_changes == 0)
1174				return 0;
1175			/*
1176			 * A non-blocking test if the fs is frozen. We must not
1177			 * start a new transaction here otherwise a deadlock
1178			 * happens. The pending operations are delayed to the
1179			 * next commit after thawing.
1180			 */
1181			if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
1182				__sb_end_write(sb, SB_FREEZE_WRITE);
1183			else
1184				return 0;
1185			trans = btrfs_start_transaction(root, 0);
1186		}
1187		if (IS_ERR(trans))
1188			return PTR_ERR(trans);
1189	}
1190	return btrfs_commit_transaction(trans, root);
 
 
 
 
 
 
1191}
1192
1193static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1194{
1195	struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1196	struct btrfs_root *root = info->tree_root;
1197	char *compress_type;
 
1198
1199	if (btrfs_test_opt(root, DEGRADED))
1200		seq_puts(seq, ",degraded");
1201	if (btrfs_test_opt(root, NODATASUM))
1202		seq_puts(seq, ",nodatasum");
1203	if (btrfs_test_opt(root, NODATACOW))
1204		seq_puts(seq, ",nodatacow");
1205	if (btrfs_test_opt(root, NOBARRIER))
1206		seq_puts(seq, ",nobarrier");
1207	if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1208		seq_printf(seq, ",max_inline=%llu", info->max_inline);
1209	if (info->alloc_start != 0)
1210		seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
1211	if (info->thread_pool_size !=  min_t(unsigned long,
1212					     num_online_cpus() + 2, 8))
1213		seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1214	if (btrfs_test_opt(root, COMPRESS)) {
1215		if (info->compress_type == BTRFS_COMPRESS_ZLIB)
1216			compress_type = "zlib";
1217		else
1218			compress_type = "lzo";
1219		if (btrfs_test_opt(root, FORCE_COMPRESS))
1220			seq_printf(seq, ",compress-force=%s", compress_type);
1221		else
1222			seq_printf(seq, ",compress=%s", compress_type);
 
 
1223	}
1224	if (btrfs_test_opt(root, NOSSD))
1225		seq_puts(seq, ",nossd");
1226	if (btrfs_test_opt(root, SSD_SPREAD))
1227		seq_puts(seq, ",ssd_spread");
1228	else if (btrfs_test_opt(root, SSD))
1229		seq_puts(seq, ",ssd");
1230	if (btrfs_test_opt(root, NOTREELOG))
1231		seq_puts(seq, ",notreelog");
1232	if (btrfs_test_opt(root, NOLOGREPLAY))
1233		seq_puts(seq, ",nologreplay");
1234	if (btrfs_test_opt(root, FLUSHONCOMMIT))
 
 
 
 
 
 
1235		seq_puts(seq, ",flushoncommit");
1236	if (btrfs_test_opt(root, DISCARD))
1237		seq_puts(seq, ",discard");
1238	if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
 
 
1239		seq_puts(seq, ",noacl");
1240	if (btrfs_test_opt(root, SPACE_CACHE))
1241		seq_puts(seq, ",space_cache");
1242	else if (btrfs_test_opt(root, FREE_SPACE_TREE))
1243		seq_puts(seq, ",space_cache=v2");
1244	else
1245		seq_puts(seq, ",nospace_cache");
1246	if (btrfs_test_opt(root, RESCAN_UUID_TREE))
1247		seq_puts(seq, ",rescan_uuid_tree");
1248	if (btrfs_test_opt(root, CLEAR_CACHE))
1249		seq_puts(seq, ",clear_cache");
1250	if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
1251		seq_puts(seq, ",user_subvol_rm_allowed");
1252	if (btrfs_test_opt(root, ENOSPC_DEBUG))
1253		seq_puts(seq, ",enospc_debug");
1254	if (btrfs_test_opt(root, AUTO_DEFRAG))
1255		seq_puts(seq, ",autodefrag");
1256	if (btrfs_test_opt(root, INODE_MAP_CACHE))
1257		seq_puts(seq, ",inode_cache");
1258	if (btrfs_test_opt(root, SKIP_BALANCE))
1259		seq_puts(seq, ",skip_balance");
1260#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1261	if (btrfs_test_opt(root, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1262		seq_puts(seq, ",check_int_data");
1263	else if (btrfs_test_opt(root, CHECK_INTEGRITY))
1264		seq_puts(seq, ",check_int");
1265	if (info->check_integrity_print_mask)
1266		seq_printf(seq, ",check_int_print_mask=%d",
1267				info->check_integrity_print_mask);
1268#endif
1269	if (info->metadata_ratio)
1270		seq_printf(seq, ",metadata_ratio=%d",
1271				info->metadata_ratio);
1272	if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
1273		seq_puts(seq, ",fatal_errors=panic");
1274	if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1275		seq_printf(seq, ",commit=%d", info->commit_interval);
1276#ifdef CONFIG_BTRFS_DEBUG
1277	if (btrfs_test_opt(root, FRAGMENT_DATA))
1278		seq_puts(seq, ",fragment=data");
1279	if (btrfs_test_opt(root, FRAGMENT_METADATA))
1280		seq_puts(seq, ",fragment=metadata");
1281#endif
 
 
1282	seq_printf(seq, ",subvolid=%llu",
1283		  BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1284	seq_puts(seq, ",subvol=");
1285	seq_dentry(seq, dentry, " \t\n\\");
 
 
 
 
 
1286	return 0;
1287}
1288
1289static int btrfs_test_super(struct super_block *s, void *data)
1290{
1291	struct btrfs_fs_info *p = data;
1292	struct btrfs_fs_info *fs_info = btrfs_sb(s);
1293
1294	return fs_info->fs_devices == p->fs_devices;
1295}
1296
1297static int btrfs_set_super(struct super_block *s, void *data)
1298{
1299	int err = set_anon_super(s, data);
1300	if (!err)
1301		s->s_fs_info = data;
1302	return err;
1303}
1304
1305/*
1306 * subvolumes are identified by ino 256
1307 */
1308static inline int is_subvolume_inode(struct inode *inode)
1309{
1310	if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1311		return 1;
1312	return 0;
1313}
1314
1315/*
1316 * This will add subvolid=0 to the argument string while removing any subvol=
1317 * and subvolid= arguments to make sure we get the top-level root for path
1318 * walking to the subvol we want.
1319 */
1320static char *setup_root_args(char *args)
1321{
1322	char *buf, *dst, *sep;
1323
1324	if (!args)
1325		return kstrdup("subvolid=0", GFP_NOFS);
1326
1327	/* The worst case is that we add ",subvolid=0" to the end. */
1328	buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1, GFP_NOFS);
1329	if (!buf)
1330		return NULL;
1331
1332	while (1) {
1333		sep = strchrnul(args, ',');
1334		if (!strstarts(args, "subvol=") &&
1335		    !strstarts(args, "subvolid=")) {
1336			memcpy(dst, args, sep - args);
1337			dst += sep - args;
1338			*dst++ = ',';
1339		}
1340		if (*sep)
1341			args = sep + 1;
1342		else
1343			break;
1344	}
1345	strcpy(dst, "subvolid=0");
1346
1347	return buf;
1348}
1349
1350static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1351				   int flags, const char *device_name,
1352				   char *data)
1353{
1354	struct dentry *root;
1355	struct vfsmount *mnt = NULL;
1356	char *newargs;
1357	int ret;
1358
1359	newargs = setup_root_args(data);
1360	if (!newargs) {
1361		root = ERR_PTR(-ENOMEM);
1362		goto out;
1363	}
1364
1365	mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs);
1366	if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) {
1367		if (flags & MS_RDONLY) {
1368			mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY,
1369					     device_name, newargs);
1370		} else {
1371			mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY,
1372					     device_name, newargs);
1373			if (IS_ERR(mnt)) {
1374				root = ERR_CAST(mnt);
1375				mnt = NULL;
1376				goto out;
1377			}
1378
1379			down_write(&mnt->mnt_sb->s_umount);
1380			ret = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1381			up_write(&mnt->mnt_sb->s_umount);
1382			if (ret < 0) {
1383				root = ERR_PTR(ret);
1384				goto out;
1385			}
1386		}
1387	}
1388	if (IS_ERR(mnt)) {
1389		root = ERR_CAST(mnt);
1390		mnt = NULL;
1391		goto out;
1392	}
1393
1394	if (!subvol_name) {
1395		if (!subvol_objectid) {
1396			ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1397							  &subvol_objectid);
1398			if (ret) {
1399				root = ERR_PTR(ret);
1400				goto out;
1401			}
1402		}
1403		subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1404							    subvol_objectid);
1405		if (IS_ERR(subvol_name)) {
1406			root = ERR_CAST(subvol_name);
1407			subvol_name = NULL;
1408			goto out;
1409		}
1410
1411	}
1412
1413	root = mount_subtree(mnt, subvol_name);
1414	/* mount_subtree() drops our reference on the vfsmount. */
1415	mnt = NULL;
1416
1417	if (!IS_ERR(root)) {
1418		struct super_block *s = root->d_sb;
 
1419		struct inode *root_inode = d_inode(root);
1420		u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1421
1422		ret = 0;
1423		if (!is_subvolume_inode(root_inode)) {
1424			pr_err("BTRFS: '%s' is not a valid subvolume\n",
1425			       subvol_name);
1426			ret = -EINVAL;
1427		}
1428		if (subvol_objectid && root_objectid != subvol_objectid) {
1429			/*
1430			 * This will also catch a race condition where a
1431			 * subvolume which was passed by ID is renamed and
1432			 * another subvolume is renamed over the old location.
1433			 */
1434			pr_err("BTRFS: subvol '%s' does not match subvolid %llu\n",
1435			       subvol_name, subvol_objectid);
 
1436			ret = -EINVAL;
1437		}
1438		if (ret) {
1439			dput(root);
1440			root = ERR_PTR(ret);
1441			deactivate_locked_super(s);
1442		}
1443	}
1444
1445out:
1446	mntput(mnt);
1447	kfree(newargs);
1448	kfree(subvol_name);
1449	return root;
1450}
1451
1452static int parse_security_options(char *orig_opts,
1453				  struct security_mnt_opts *sec_opts)
1454{
1455	char *secdata = NULL;
1456	int ret = 0;
1457
1458	secdata = alloc_secdata();
1459	if (!secdata)
1460		return -ENOMEM;
1461	ret = security_sb_copy_data(orig_opts, secdata);
1462	if (ret) {
1463		free_secdata(secdata);
1464		return ret;
1465	}
1466	ret = security_sb_parse_opts_str(secdata, sec_opts);
1467	free_secdata(secdata);
1468	return ret;
1469}
1470
1471static int setup_security_options(struct btrfs_fs_info *fs_info,
1472				  struct super_block *sb,
1473				  struct security_mnt_opts *sec_opts)
1474{
1475	int ret = 0;
1476
1477	/*
1478	 * Call security_sb_set_mnt_opts() to check whether new sec_opts
1479	 * is valid.
1480	 */
1481	ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1482	if (ret)
1483		return ret;
1484
1485#ifdef CONFIG_SECURITY
1486	if (!fs_info->security_opts.num_mnt_opts) {
1487		/* first time security setup, copy sec_opts to fs_info */
1488		memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1489	} else {
1490		/*
1491		 * Since SELinux(the only one supports security_mnt_opts) does
1492		 * NOT support changing context during remount/mount same sb,
1493		 * This must be the same or part of the same security options,
1494		 * just free it.
1495		 */
1496		security_free_mnt_opts(sec_opts);
1497	}
1498#endif
1499	return ret;
1500}
1501
1502/*
1503 * Find a superblock for the given device / mount point.
1504 *
1505 * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
1506 *	  for multiple device setup.  Make sure to keep it in sync.
1507 */
1508static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1509		const char *device_name, void *data)
1510{
1511	struct block_device *bdev = NULL;
1512	struct super_block *s;
 
1513	struct btrfs_fs_devices *fs_devices = NULL;
1514	struct btrfs_fs_info *fs_info = NULL;
1515	struct security_mnt_opts new_sec_opts;
1516	fmode_t mode = FMODE_READ;
1517	char *subvol_name = NULL;
1518	u64 subvol_objectid = 0;
1519	int error = 0;
1520
1521	if (!(flags & MS_RDONLY))
1522		mode |= FMODE_WRITE;
1523
1524	error = btrfs_parse_early_options(data, mode, fs_type,
1525					  &subvol_name, &subvol_objectid,
1526					  &fs_devices);
1527	if (error) {
1528		kfree(subvol_name);
1529		return ERR_PTR(error);
1530	}
1531
1532	if (subvol_name || subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1533		/* mount_subvol() will free subvol_name. */
1534		return mount_subvol(subvol_name, subvol_objectid, flags,
1535				    device_name, data);
1536	}
1537
1538	security_init_mnt_opts(&new_sec_opts);
1539	if (data) {
1540		error = parse_security_options(data, &new_sec_opts);
1541		if (error)
1542			return ERR_PTR(error);
1543	}
1544
1545	error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1546	if (error)
1547		goto error_sec_opts;
1548
1549	/*
1550	 * Setup a dummy root and fs_info for test/set super.  This is because
1551	 * we don't actually fill this stuff out until open_ctree, but we need
1552	 * it for searching for existing supers, so this lets us do that and
1553	 * then open_ctree will properly initialize everything later.
 
 
1554	 */
1555	fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1556	if (!fs_info) {
1557		error = -ENOMEM;
1558		goto error_sec_opts;
1559	}
 
1560
1561	fs_info->fs_devices = fs_devices;
1562
1563	fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1564	fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1565	security_init_mnt_opts(&fs_info->security_opts);
1566	if (!fs_info->super_copy || !fs_info->super_for_commit) {
1567		error = -ENOMEM;
1568		goto error_fs_info;
1569	}
1570
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1571	error = btrfs_open_devices(fs_devices, mode, fs_type);
 
1572	if (error)
1573		goto error_fs_info;
1574
1575	if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1576		error = -EACCES;
1577		goto error_close_devices;
1578	}
1579
1580	bdev = fs_devices->latest_bdev;
1581	s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1582		 fs_info);
1583	if (IS_ERR(s)) {
1584		error = PTR_ERR(s);
1585		goto error_close_devices;
1586	}
1587
1588	if (s->s_root) {
1589		btrfs_close_devices(fs_devices);
1590		free_fs_info(fs_info);
1591		if ((flags ^ s->s_flags) & MS_RDONLY)
1592			error = -EBUSY;
1593	} else {
1594		snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1595		btrfs_sb(s)->bdev_holder = fs_type;
1596		error = btrfs_fill_super(s, fs_devices, data,
1597					 flags & MS_SILENT ? 1 : 0);
1598	}
1599	if (error) {
1600		deactivate_locked_super(s);
1601		goto error_sec_opts;
1602	}
1603
1604	fs_info = btrfs_sb(s);
1605	error = setup_security_options(fs_info, s, &new_sec_opts);
1606	if (error) {
1607		deactivate_locked_super(s);
1608		goto error_sec_opts;
1609	}
1610
1611	return dget(s->s_root);
1612
1613error_close_devices:
1614	btrfs_close_devices(fs_devices);
1615error_fs_info:
1616	free_fs_info(fs_info);
1617error_sec_opts:
1618	security_free_mnt_opts(&new_sec_opts);
1619	return ERR_PTR(error);
1620}
1621
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1622static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1623				     int new_pool_size, int old_pool_size)
1624{
1625	if (new_pool_size == old_pool_size)
1626		return;
1627
1628	fs_info->thread_pool_size = new_pool_size;
1629
1630	btrfs_info(fs_info, "resize thread pool %d -> %d",
1631	       old_pool_size, new_pool_size);
1632
1633	btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1634	btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1635	btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1636	btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1637	btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1638	btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1639	btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1640				new_pool_size);
1641	btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1642	btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1643	btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1644	btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1645	btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1646				new_pool_size);
1647}
1648
1649static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1650{
1651	set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1652}
1653
1654static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1655				       unsigned long old_opts, int flags)
1656{
1657	if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1658	    (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1659	     (flags & MS_RDONLY))) {
1660		/* wait for any defraggers to finish */
1661		wait_event(fs_info->transaction_wait,
1662			   (atomic_read(&fs_info->defrag_running) == 0));
1663		if (flags & MS_RDONLY)
1664			sync_filesystem(fs_info->sb);
1665	}
1666}
1667
1668static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1669					 unsigned long old_opts)
1670{
 
 
1671	/*
1672	 * We need cleanup all defragable inodes if the autodefragment is
1673	 * close or the fs is R/O.
1674	 */
1675	if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1676	    (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1677	     (fs_info->sb->s_flags & MS_RDONLY))) {
1678		btrfs_cleanup_defrag_inodes(fs_info);
1679	}
1680
1681	clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
 
 
 
 
 
 
 
 
 
 
1682}
1683
1684static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1685{
1686	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1687	struct btrfs_root *root = fs_info->tree_root;
1688	unsigned old_flags = sb->s_flags;
1689	unsigned long old_opts = fs_info->mount_opt;
1690	unsigned long old_compress_type = fs_info->compress_type;
1691	u64 old_max_inline = fs_info->max_inline;
1692	u64 old_alloc_start = fs_info->alloc_start;
1693	int old_thread_pool_size = fs_info->thread_pool_size;
1694	unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1695	int ret;
1696
1697	sync_filesystem(sb);
1698	btrfs_remount_prepare(fs_info);
1699
1700	if (data) {
1701		struct security_mnt_opts new_sec_opts;
1702
1703		security_init_mnt_opts(&new_sec_opts);
1704		ret = parse_security_options(data, &new_sec_opts);
 
 
1705		if (ret)
1706			goto restore;
1707		ret = setup_security_options(fs_info, sb,
1708					     &new_sec_opts);
1709		if (ret) {
1710			security_free_mnt_opts(&new_sec_opts);
1711			goto restore;
1712		}
1713	}
1714
1715	ret = btrfs_parse_options(root, data, *flags);
1716	if (ret) {
1717		ret = -EINVAL;
1718		goto restore;
1719	}
1720
1721	btrfs_remount_begin(fs_info, old_opts, *flags);
1722	btrfs_resize_thread_pool(fs_info,
1723		fs_info->thread_pool_size, old_thread_pool_size);
1724
1725	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1726		goto out;
1727
1728	if (*flags & MS_RDONLY) {
1729		/*
1730		 * this also happens on 'umount -rf' or on shutdown, when
1731		 * the filesystem is busy.
1732		 */
1733		cancel_work_sync(&fs_info->async_reclaim_work);
 
 
 
1734
1735		/* wait for the uuid_scan task to finish */
1736		down(&fs_info->uuid_tree_rescan_sem);
1737		/* avoid complains from lockdep et al. */
1738		up(&fs_info->uuid_tree_rescan_sem);
1739
1740		sb->s_flags |= MS_RDONLY;
1741
1742		/*
1743		 * Setting MS_RDONLY will put the cleaner thread to
1744		 * sleep at the next loop if it's already active.
1745		 * If it's already asleep, we'll leave unused block
1746		 * groups on disk until we're mounted read-write again
1747		 * unless we clean them up here.
1748		 */
1749		btrfs_delete_unused_bgs(fs_info);
1750
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1751		btrfs_dev_replace_suspend_for_unmount(fs_info);
1752		btrfs_scrub_cancel(fs_info);
1753		btrfs_pause_balance(fs_info);
1754
1755		ret = btrfs_commit_super(root);
 
 
 
 
 
 
 
 
1756		if (ret)
1757			goto restore;
1758	} else {
1759		if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1760			btrfs_err(fs_info,
1761				"Remounting read-write after error is not allowed");
1762			ret = -EINVAL;
1763			goto restore;
1764		}
1765		if (fs_info->fs_devices->rw_devices == 0) {
1766			ret = -EACCES;
1767			goto restore;
1768		}
1769
1770		if (fs_info->fs_devices->missing_devices >
1771		     fs_info->num_tolerated_disk_barrier_failures &&
1772		    !(*flags & MS_RDONLY)) {
1773			btrfs_warn(fs_info,
1774				"too many missing devices, writeable remount is not allowed");
1775			ret = -EACCES;
1776			goto restore;
1777		}
1778
1779		if (btrfs_super_log_root(fs_info->super_copy) != 0) {
 
 
1780			ret = -EINVAL;
1781			goto restore;
1782		}
1783
1784		ret = btrfs_cleanup_fs_roots(fs_info);
1785		if (ret)
1786			goto restore;
1787
1788		/* recover relocation */
1789		mutex_lock(&fs_info->cleaner_mutex);
1790		ret = btrfs_recover_relocation(root);
1791		mutex_unlock(&fs_info->cleaner_mutex);
1792		if (ret)
1793			goto restore;
 
1794
1795		ret = btrfs_resume_balance_async(fs_info);
 
 
 
 
 
1796		if (ret)
1797			goto restore;
1798
1799		ret = btrfs_resume_dev_replace_async(fs_info);
1800		if (ret) {
1801			btrfs_warn(fs_info, "failed to resume dev_replace");
1802			goto restore;
1803		}
1804
1805		if (!fs_info->uuid_root) {
1806			btrfs_info(fs_info, "creating UUID tree");
1807			ret = btrfs_create_uuid_tree(fs_info);
1808			if (ret) {
1809				btrfs_warn(fs_info, "failed to create the UUID tree %d", ret);
1810				goto restore;
1811			}
1812		}
1813		sb->s_flags &= ~MS_RDONLY;
1814	}
1815out:
 
 
 
 
 
 
1816	wake_up_process(fs_info->transaction_kthread);
1817	btrfs_remount_cleanup(fs_info, old_opts);
 
 
 
1818	return 0;
1819
1820restore:
1821	/* We've hit an error - don't reset MS_RDONLY */
1822	if (sb->s_flags & MS_RDONLY)
1823		old_flags |= MS_RDONLY;
 
 
1824	sb->s_flags = old_flags;
1825	fs_info->mount_opt = old_opts;
1826	fs_info->compress_type = old_compress_type;
1827	fs_info->max_inline = old_max_inline;
1828	mutex_lock(&fs_info->chunk_mutex);
1829	fs_info->alloc_start = old_alloc_start;
1830	mutex_unlock(&fs_info->chunk_mutex);
1831	btrfs_resize_thread_pool(fs_info,
1832		old_thread_pool_size, fs_info->thread_pool_size);
1833	fs_info->metadata_ratio = old_metadata_ratio;
1834	btrfs_remount_cleanup(fs_info, old_opts);
 
 
1835	return ret;
1836}
1837
1838/* Used to sort the devices by max_avail(descending sort) */
1839static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1840				       const void *dev_info2)
1841{
1842	if (((struct btrfs_device_info *)dev_info1)->max_avail >
1843	    ((struct btrfs_device_info *)dev_info2)->max_avail)
1844		return -1;
1845	else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1846		 ((struct btrfs_device_info *)dev_info2)->max_avail)
1847		return 1;
1848	else
1849	return 0;
1850}
1851
1852/*
1853 * sort the devices by max_avail, in which max free extent size of each device
1854 * is stored.(Descending Sort)
1855 */
1856static inline void btrfs_descending_sort_devices(
1857					struct btrfs_device_info *devices,
1858					size_t nr_devices)
1859{
1860	sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1861	     btrfs_cmp_device_free_bytes, NULL);
1862}
1863
1864/*
1865 * The helper to calc the free space on the devices that can be used to store
1866 * file data.
1867 */
1868static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
 
1869{
1870	struct btrfs_fs_info *fs_info = root->fs_info;
1871	struct btrfs_device_info *devices_info;
1872	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1873	struct btrfs_device *device;
1874	u64 skip_space;
1875	u64 type;
1876	u64 avail_space;
1877	u64 used_space;
1878	u64 min_stripe_size;
1879	int min_stripes = 1, num_stripes = 1;
1880	int i = 0, nr_devices;
1881	int ret;
1882
1883	/*
1884	 * We aren't under the device list lock, so this is racey-ish, but good
1885	 * enough for our purposes.
1886	 */
1887	nr_devices = fs_info->fs_devices->open_devices;
1888	if (!nr_devices) {
1889		smp_mb();
1890		nr_devices = fs_info->fs_devices->open_devices;
1891		ASSERT(nr_devices);
1892		if (!nr_devices) {
1893			*free_bytes = 0;
1894			return 0;
1895		}
1896	}
1897
1898	devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1899			       GFP_NOFS);
1900	if (!devices_info)
1901		return -ENOMEM;
1902
1903	/* calc min stripe number for data space alloction */
1904	type = btrfs_get_alloc_profile(root, 1);
1905	if (type & BTRFS_BLOCK_GROUP_RAID0) {
1906		min_stripes = 2;
 
1907		num_stripes = nr_devices;
1908	} else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1909		min_stripes = 2;
1910		num_stripes = 2;
1911	} else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1912		min_stripes = 4;
 
 
 
1913		num_stripes = 4;
1914	}
1915
1916	if (type & BTRFS_BLOCK_GROUP_DUP)
1917		min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1918	else
1919		min_stripe_size = BTRFS_STRIPE_LEN;
1920
1921	if (fs_info->alloc_start)
1922		mutex_lock(&fs_devices->device_list_mutex);
1923	rcu_read_lock();
1924	list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1925		if (!device->in_fs_metadata || !device->bdev ||
1926		    device->is_tgtdev_for_dev_replace)
 
 
1927			continue;
1928
1929		if (i >= nr_devices)
1930			break;
1931
1932		avail_space = device->total_bytes - device->bytes_used;
1933
1934		/* align with stripe_len */
1935		avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
1936		avail_space *= BTRFS_STRIPE_LEN;
1937
1938		/*
1939		 * In order to avoid overwritting the superblock on the drive,
1940		 * btrfs starts at an offset of at least 1MB when doing chunk
1941		 * allocation.
 
 
 
1942		 */
1943		skip_space = SZ_1M;
1944
1945		/* user can set the offset in fs_info->alloc_start. */
1946		if (fs_info->alloc_start &&
1947		    fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1948		    device->total_bytes) {
1949			rcu_read_unlock();
1950			skip_space = max(fs_info->alloc_start, skip_space);
1951
1952			/*
1953			 * btrfs can not use the free space in
1954			 * [0, skip_space - 1], we must subtract it from the
1955			 * total. In order to implement it, we account the used
1956			 * space in this range first.
1957			 */
1958			ret = btrfs_account_dev_extents_size(device, 0,
1959							     skip_space - 1,
1960							     &used_space);
1961			if (ret) {
1962				kfree(devices_info);
1963				mutex_unlock(&fs_devices->device_list_mutex);
1964				return ret;
1965			}
1966
1967			rcu_read_lock();
1968
1969			/* calc the free space in [0, skip_space - 1] */
1970			skip_space -= used_space;
1971		}
1972
1973		/*
1974		 * we can use the free space in [0, skip_space - 1], subtract
1975		 * it from the total.
1976		 */
1977		if (avail_space && avail_space >= skip_space)
1978			avail_space -= skip_space;
1979		else
1980			avail_space = 0;
1981
1982		if (avail_space < min_stripe_size)
1983			continue;
1984
 
 
1985		devices_info[i].dev = device;
1986		devices_info[i].max_avail = avail_space;
1987
1988		i++;
1989	}
1990	rcu_read_unlock();
1991	if (fs_info->alloc_start)
1992		mutex_unlock(&fs_devices->device_list_mutex);
1993
1994	nr_devices = i;
1995
1996	btrfs_descending_sort_devices(devices_info, nr_devices);
1997
1998	i = nr_devices - 1;
1999	avail_space = 0;
2000	while (nr_devices >= min_stripes) {
2001		if (num_stripes > nr_devices)
2002			num_stripes = nr_devices;
2003
2004		if (devices_info[i].max_avail >= min_stripe_size) {
2005			int j;
2006			u64 alloc_size;
2007
2008			avail_space += devices_info[i].max_avail * num_stripes;
2009			alloc_size = devices_info[i].max_avail;
2010			for (j = i + 1 - num_stripes; j <= i; j++)
2011				devices_info[j].max_avail -= alloc_size;
2012		}
2013		i--;
2014		nr_devices--;
2015	}
2016
2017	kfree(devices_info);
2018	*free_bytes = avail_space;
2019	return 0;
2020}
2021
2022/*
2023 * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2024 *
2025 * If there's a redundant raid level at DATA block groups, use the respective
2026 * multiplier to scale the sizes.
2027 *
2028 * Unused device space usage is based on simulating the chunk allocator
2029 * algorithm that respects the device sizes, order of allocations and the
2030 * 'alloc_start' value, this is a close approximation of the actual use but
2031 * there are other factors that may change the result (like a new metadata
2032 * chunk).
2033 *
2034 * If metadata is exhausted, f_bavail will be 0.
2035 *
2036 * FIXME: not accurate for mixed block groups, total and free/used are ok,
2037 * available appears slightly larger.
2038 */
2039static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2040{
2041	struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2042	struct btrfs_super_block *disk_super = fs_info->super_copy;
2043	struct list_head *head = &fs_info->space_info;
2044	struct btrfs_space_info *found;
2045	u64 total_used = 0;
2046	u64 total_free_data = 0;
2047	u64 total_free_meta = 0;
2048	int bits = dentry->d_sb->s_blocksize_bits;
2049	__be32 *fsid = (__be32 *)fs_info->fsid;
2050	unsigned factor = 1;
2051	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2052	int ret;
2053	u64 thresh = 0;
 
2054
2055	/*
2056	 * holding chunk_muext to avoid allocating new chunks, holding
2057	 * device_list_mutex to avoid the device being removed
2058	 */
2059	rcu_read_lock();
2060	list_for_each_entry_rcu(found, head, list) {
2061		if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2062			int i;
2063
2064			total_free_data += found->disk_total - found->disk_used;
2065			total_free_data -=
2066				btrfs_account_ro_block_groups_free_space(found);
2067
2068			for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2069				if (!list_empty(&found->block_groups[i])) {
2070					switch (i) {
2071					case BTRFS_RAID_DUP:
2072					case BTRFS_RAID_RAID1:
2073					case BTRFS_RAID_RAID10:
2074						factor = 2;
2075					}
2076				}
2077			}
2078		}
2079		if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
2080			total_free_meta += found->disk_total - found->disk_used;
 
 
 
 
 
 
 
 
 
2081
2082		total_used += found->disk_used;
2083	}
2084
2085	rcu_read_unlock();
2086
2087	buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2088	buf->f_blocks >>= bits;
2089	buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2090
2091	/* Account global block reserve as used, it's in logical size already */
2092	spin_lock(&block_rsv->lock);
2093	buf->f_bfree -= block_rsv->size >> bits;
 
 
 
 
2094	spin_unlock(&block_rsv->lock);
2095
2096	buf->f_bavail = div_u64(total_free_data, factor);
2097	ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
2098	if (ret)
2099		return ret;
2100	buf->f_bavail += div_u64(total_free_data, factor);
2101	buf->f_bavail = buf->f_bavail >> bits;
2102
2103	/*
2104	 * We calculate the remaining metadata space minus global reserve. If
2105	 * this is (supposedly) smaller than zero, there's no space. But this
2106	 * does not hold in practice, the exhausted state happens where's still
2107	 * some positive delta. So we apply some guesswork and compare the
2108	 * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2109	 *
2110	 * We probably cannot calculate the exact threshold value because this
2111	 * depends on the internal reservations requested by various
2112	 * operations, so some operations that consume a few metadata will
2113	 * succeed even if the Avail is zero. But this is better than the other
2114	 * way around.
2115	 */
2116	thresh = 4 * 1024 * 1024;
2117
2118	if (total_free_meta - thresh < block_rsv->size)
 
 
 
 
 
 
 
 
2119		buf->f_bavail = 0;
2120
2121	buf->f_type = BTRFS_SUPER_MAGIC;
2122	buf->f_bsize = dentry->d_sb->s_blocksize;
2123	buf->f_namelen = BTRFS_NAME_LEN;
2124
2125	/* We treat it as constant endianness (it doesn't matter _which_)
2126	   because we want the fsid to come out the same whether mounted
2127	   on a big-endian or little-endian host */
2128	buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2129	buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2130	/* Mask in the root object ID too, to disambiguate subvols */
2131	buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2132	buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
 
 
2133
2134	return 0;
2135}
2136
2137static void btrfs_kill_super(struct super_block *sb)
2138{
2139	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2140	kill_anon_super(sb);
2141	free_fs_info(fs_info);
2142}
2143
2144static struct file_system_type btrfs_fs_type = {
2145	.owner		= THIS_MODULE,
2146	.name		= "btrfs",
2147	.mount		= btrfs_mount,
2148	.kill_sb	= btrfs_kill_super,
2149	.fs_flags	= FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2150};
 
 
 
 
 
 
 
 
 
2151MODULE_ALIAS_FS("btrfs");
2152
2153static int btrfs_control_open(struct inode *inode, struct file *file)
2154{
2155	/*
2156	 * The control file's private_data is used to hold the
2157	 * transaction when it is started and is used to keep
2158	 * track of whether a transaction is already in progress.
2159	 */
2160	file->private_data = NULL;
2161	return 0;
2162}
2163
2164/*
2165 * used by btrfsctl to scan devices when no FS is mounted
2166 */
2167static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2168				unsigned long arg)
2169{
2170	struct btrfs_ioctl_vol_args *vol;
2171	struct btrfs_fs_devices *fs_devices;
2172	int ret = -ENOTTY;
2173
2174	if (!capable(CAP_SYS_ADMIN))
2175		return -EPERM;
2176
2177	vol = memdup_user((void __user *)arg, sizeof(*vol));
2178	if (IS_ERR(vol))
2179		return PTR_ERR(vol);
 
2180
2181	switch (cmd) {
2182	case BTRFS_IOC_SCAN_DEV:
2183		ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2184					    &btrfs_fs_type, &fs_devices);
 
 
 
 
 
 
2185		break;
2186	case BTRFS_IOC_DEVICES_READY:
2187		ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2188					    &btrfs_fs_type, &fs_devices);
2189		if (ret)
 
 
 
2190			break;
2191		ret = !(fs_devices->num_devices == fs_devices->total_devices);
 
 
 
2192		break;
2193	case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2194		ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2195		break;
2196	}
2197
2198	kfree(vol);
2199	return ret;
2200}
2201
2202static int btrfs_freeze(struct super_block *sb)
2203{
2204	struct btrfs_trans_handle *trans;
2205	struct btrfs_root *root = btrfs_sb(sb)->tree_root;
 
2206
 
 
 
 
 
 
 
2207	trans = btrfs_attach_transaction_barrier(root);
2208	if (IS_ERR(trans)) {
2209		/* no transaction, don't bother */
2210		if (PTR_ERR(trans) == -ENOENT)
2211			return 0;
2212		return PTR_ERR(trans);
2213	}
2214	return btrfs_commit_transaction(trans, root);
 
 
 
 
 
 
 
 
2215}
2216
2217static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2218{
2219	struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2220	struct btrfs_fs_devices *cur_devices;
2221	struct btrfs_device *dev, *first_dev = NULL;
2222	struct list_head *head;
2223	struct rcu_string *name;
2224
2225	mutex_lock(&fs_info->fs_devices->device_list_mutex);
2226	cur_devices = fs_info->fs_devices;
2227	while (cur_devices) {
2228		head = &cur_devices->devices;
2229		list_for_each_entry(dev, head, dev_list) {
2230			if (dev->missing)
2231				continue;
2232			if (!dev->name)
2233				continue;
2234			if (!first_dev || dev->devid < first_dev->devid)
2235				first_dev = dev;
2236		}
2237		cur_devices = cur_devices->seed;
2238	}
2239
2240	if (first_dev) {
2241		rcu_read_lock();
2242		name = rcu_dereference(first_dev->name);
2243		seq_escape(m, name->str, " \t\n\\");
2244		rcu_read_unlock();
2245	} else {
2246		WARN_ON(1);
2247	}
2248	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
 
 
 
 
 
2249	return 0;
2250}
2251
2252static const struct super_operations btrfs_super_ops = {
2253	.drop_inode	= btrfs_drop_inode,
2254	.evict_inode	= btrfs_evict_inode,
2255	.put_super	= btrfs_put_super,
2256	.sync_fs	= btrfs_sync_fs,
2257	.show_options	= btrfs_show_options,
2258	.show_devname	= btrfs_show_devname,
2259	.write_inode	= btrfs_write_inode,
2260	.alloc_inode	= btrfs_alloc_inode,
2261	.destroy_inode	= btrfs_destroy_inode,
 
2262	.statfs		= btrfs_statfs,
2263	.remount_fs	= btrfs_remount,
2264	.freeze_fs	= btrfs_freeze,
 
2265};
2266
2267static const struct file_operations btrfs_ctl_fops = {
2268	.open = btrfs_control_open,
2269	.unlocked_ioctl	 = btrfs_control_ioctl,
2270	.compat_ioctl = btrfs_control_ioctl,
2271	.owner	 = THIS_MODULE,
2272	.llseek = noop_llseek,
2273};
2274
2275static struct miscdevice btrfs_misc = {
2276	.minor		= BTRFS_MINOR,
2277	.name		= "btrfs-control",
2278	.fops		= &btrfs_ctl_fops
2279};
2280
2281MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2282MODULE_ALIAS("devname:btrfs-control");
2283
2284static int btrfs_interface_init(void)
2285{
2286	return misc_register(&btrfs_misc);
2287}
2288
2289static void btrfs_interface_exit(void)
2290{
2291	misc_deregister(&btrfs_misc);
2292}
2293
2294static void btrfs_print_mod_info(void)
2295{
2296	printk(KERN_INFO "Btrfs loaded"
2297#ifdef CONFIG_BTRFS_DEBUG
2298			", debug=on"
2299#endif
2300#ifdef CONFIG_BTRFS_ASSERT
2301			", assert=on"
2302#endif
2303#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2304			", integrity-checker=on"
2305#endif
2306			"\n");
2307}
2308
2309static int btrfs_run_sanity_tests(void)
2310{
2311	int ret;
2312
2313	ret = btrfs_init_test_fs();
2314	if (ret)
2315		return ret;
2316
2317	ret = btrfs_test_free_space_cache();
2318	if (ret)
2319		goto out;
2320	ret = btrfs_test_extent_buffer_operations();
2321	if (ret)
2322		goto out;
2323	ret = btrfs_test_extent_io();
2324	if (ret)
2325		goto out;
2326	ret = btrfs_test_inodes();
2327	if (ret)
2328		goto out;
2329	ret = btrfs_test_qgroups();
2330	if (ret)
2331		goto out;
2332	ret = btrfs_test_free_space_tree();
2333out:
2334	btrfs_destroy_test_fs();
2335	return ret;
2336}
2337
2338static int __init init_btrfs_fs(void)
2339{
2340	int err;
2341
2342	err = btrfs_hash_init();
2343	if (err)
2344		return err;
2345
2346	btrfs_props_init();
2347
2348	err = btrfs_init_sysfs();
2349	if (err)
2350		goto free_hash;
2351
2352	btrfs_init_compress();
2353
2354	err = btrfs_init_cachep();
2355	if (err)
2356		goto free_compress;
2357
2358	err = extent_io_init();
2359	if (err)
2360		goto free_cachep;
2361
2362	err = extent_map_init();
2363	if (err)
2364		goto free_extent_io;
2365
 
 
 
 
2366	err = ordered_data_init();
2367	if (err)
2368		goto free_extent_map;
2369
2370	err = btrfs_delayed_inode_init();
2371	if (err)
2372		goto free_ordered_data;
2373
2374	err = btrfs_auto_defrag_init();
2375	if (err)
2376		goto free_delayed_inode;
2377
2378	err = btrfs_delayed_ref_init();
2379	if (err)
2380		goto free_auto_defrag;
2381
2382	err = btrfs_prelim_ref_init();
2383	if (err)
2384		goto free_delayed_ref;
2385
2386	err = btrfs_end_io_wq_init();
2387	if (err)
2388		goto free_prelim_ref;
2389
2390	err = btrfs_interface_init();
2391	if (err)
2392		goto free_end_io_wq;
2393
2394	btrfs_init_lockdep();
2395
2396	btrfs_print_mod_info();
2397
2398	err = btrfs_run_sanity_tests();
2399	if (err)
2400		goto unregister_ioctl;
2401
2402	err = register_filesystem(&btrfs_fs_type);
2403	if (err)
2404		goto unregister_ioctl;
2405
2406	return 0;
2407
2408unregister_ioctl:
2409	btrfs_interface_exit();
2410free_end_io_wq:
2411	btrfs_end_io_wq_exit();
2412free_prelim_ref:
2413	btrfs_prelim_ref_exit();
2414free_delayed_ref:
2415	btrfs_delayed_ref_exit();
2416free_auto_defrag:
2417	btrfs_auto_defrag_exit();
2418free_delayed_inode:
2419	btrfs_delayed_inode_exit();
2420free_ordered_data:
2421	ordered_data_exit();
2422free_extent_map:
2423	extent_map_exit();
 
 
2424free_extent_io:
2425	extent_io_exit();
2426free_cachep:
2427	btrfs_destroy_cachep();
2428free_compress:
2429	btrfs_exit_compress();
2430	btrfs_exit_sysfs();
2431free_hash:
2432	btrfs_hash_exit();
2433	return err;
2434}
2435
2436static void __exit exit_btrfs_fs(void)
2437{
2438	btrfs_destroy_cachep();
2439	btrfs_delayed_ref_exit();
2440	btrfs_auto_defrag_exit();
2441	btrfs_delayed_inode_exit();
2442	btrfs_prelim_ref_exit();
2443	ordered_data_exit();
2444	extent_map_exit();
 
2445	extent_io_exit();
2446	btrfs_interface_exit();
2447	btrfs_end_io_wq_exit();
2448	unregister_filesystem(&btrfs_fs_type);
2449	btrfs_exit_sysfs();
2450	btrfs_cleanup_fs_uuids();
2451	btrfs_exit_compress();
2452	btrfs_hash_exit();
2453}
2454
2455late_initcall(init_btrfs_fs);
2456module_exit(exit_btrfs_fs)
2457
2458MODULE_LICENSE("GPL");