super.c 43.3 KB
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/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

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#include <linux/blkdev.h>
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#include <linux/module.h>
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#include <linux/buffer_head.h>
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#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/time.h>
#include <linux/init.h>
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#include <linux/seq_file.h>
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#include <linux/string.h>
#include <linux/backing-dev.h>
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#include <linux/mount.h>
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#include <linux/mpage.h>
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#include <linux/swap.h>
#include <linux/writeback.h>
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#include <linux/statfs.h>
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#include <linux/compat.h>
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#include <linux/parser.h>
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#include <linux/ctype.h>
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#include <linux/namei.h>
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#include <linux/miscdevice.h>
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#include <linux/magic.h>
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#include <linux/slab.h>
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#include <linux/cleancache.h>
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#include <linux/ratelimit.h>
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#include "compat.h"
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#include "delayed-inode.h"
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#include "ctree.h"
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#include "disk-io.h"
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#include "transaction.h"
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#include "btrfs_inode.h"
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#include "ioctl.h"
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#include "print-tree.h"
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#include "xattr.h"
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#include "volumes.h"
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#include "version.h"
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#include "export.h"
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#include "compression.h"
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#include "rcu-string.h"
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#define CREATE_TRACE_POINTS
#include <trace/events/btrfs.h>

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static const struct super_operations btrfs_super_ops;
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static struct file_system_type btrfs_fs_type;
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static const char *btrfs_decode_error(struct btrfs_fs_info *fs_info, int errno,
				      char nbuf[16])
{
	char *errstr = NULL;

	switch (errno) {
	case -EIO:
		errstr = "IO failure";
		break;
	case -ENOMEM:
		errstr = "Out of memory";
		break;
	case -EROFS:
		errstr = "Readonly filesystem";
		break;
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	case -EEXIST:
		errstr = "Object already exists";
		break;
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	default:
		if (nbuf) {
			if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
				errstr = nbuf;
		}
		break;
	}

	return errstr;
}

static void __save_error_info(struct btrfs_fs_info *fs_info)
{
	/*
	 * today we only save the error info into ram.  Long term we'll
	 * also send it down to the disk
	 */
	fs_info->fs_state = BTRFS_SUPER_FLAG_ERROR;
}

static void save_error_info(struct btrfs_fs_info *fs_info)
{
	__save_error_info(fs_info);
}

/* btrfs handle error by forcing the filesystem readonly */
static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
{
	struct super_block *sb = fs_info->sb;

	if (sb->s_flags & MS_RDONLY)
		return;

	if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
		sb->s_flags |= MS_RDONLY;
		printk(KERN_INFO "btrfs is forced readonly\n");
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		__btrfs_scrub_cancel(fs_info);
//		WARN_ON(1);
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	}
}

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#ifdef CONFIG_PRINTK
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/*
 * __btrfs_std_error decodes expected errors from the caller and
 * invokes the approciate error response.
 */
void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
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		       unsigned int line, int errno, const char *fmt, ...)
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{
	struct super_block *sb = fs_info->sb;
	char nbuf[16];
	const char *errstr;
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	va_list args;
	va_start(args, fmt);
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	/*
	 * Special case: if the error is EROFS, and we're already
	 * under MS_RDONLY, then it is safe here.
	 */
	if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
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  		return;

  	errstr = btrfs_decode_error(fs_info, errno, nbuf);
	if (fmt) {
		struct va_format vaf = {
			.fmt = fmt,
			.va = &args,
		};

		printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s (%pV)\n",
			sb->s_id, function, line, errstr, &vaf);
	} else {
		printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n",
			sb->s_id, function, line, errstr);
	}
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	/* Don't go through full error handling during mount */
	if (sb->s_flags & MS_BORN) {
		save_error_info(fs_info);
		btrfs_handle_error(fs_info);
	}
	va_end(args);
}
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static const char * const logtypes[] = {
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	"emergency",
	"alert",
	"critical",
	"error",
	"warning",
	"notice",
	"info",
	"debug",
};

void btrfs_printk(struct btrfs_fs_info *fs_info, const char *fmt, ...)
{
	struct super_block *sb = fs_info->sb;
	char lvl[4];
	struct va_format vaf;
	va_list args;
	const char *type = logtypes[4];
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	int kern_level;
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	va_start(args, fmt);

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	kern_level = printk_get_level(fmt);
	if (kern_level) {
		size_t size = printk_skip_level(fmt) - fmt;
		memcpy(lvl, fmt,  size);
		lvl[size] = '\0';
		fmt += size;
		type = logtypes[kern_level - '0'];
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	} else
		*lvl = '\0';

	vaf.fmt = fmt;
	vaf.va = &args;
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	printk("%sBTRFS %s (device %s): %pV", lvl, type, sb->s_id, &vaf);
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	va_end(args);
}

#else

void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
		       unsigned int line, int errno, const char *fmt, ...)
{
	struct super_block *sb = fs_info->sb;

	/*
	 * Special case: if the error is EROFS, and we're already
	 * under MS_RDONLY, then it is safe here.
	 */
	if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
		return;

	/* Don't go through full error handling during mount */
	if (sb->s_flags & MS_BORN) {
		save_error_info(fs_info);
		btrfs_handle_error(fs_info);
	}
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}
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#endif
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/*
 * We only mark the transaction aborted and then set the file system read-only.
 * This will prevent new transactions from starting or trying to join this
 * one.
 *
 * This means that error recovery at the call site is limited to freeing
 * any local memory allocations and passing the error code up without
 * further cleanup. The transaction should complete as it normally would
 * in the call path but will return -EIO.
 *
 * We'll complete the cleanup in btrfs_end_transaction and
 * btrfs_commit_transaction.
 */
void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
			       struct btrfs_root *root, const char *function,
			       unsigned int line, int errno)
{
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	WARN_ONCE(1, KERN_DEBUG "btrfs: Transaction aborted");
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	trans->aborted = errno;
	/* Nothing used. The other threads that have joined this
	 * transaction may be able to continue. */
	if (!trans->blocks_used) {
		btrfs_printk(root->fs_info, "Aborting unused transaction.\n");
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		return;
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	}
	trans->transaction->aborted = errno;
	__btrfs_std_error(root->fs_info, function, line, errno, NULL);
}
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/*
 * __btrfs_panic decodes unexpected, fatal errors from the caller,
 * issues an alert, and either panics or BUGs, depending on mount options.
 */
void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
		   unsigned int line, int errno, const char *fmt, ...)
{
	char nbuf[16];
	char *s_id = "<unknown>";
	const char *errstr;
	struct va_format vaf = { .fmt = fmt };
	va_list args;
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	if (fs_info)
		s_id = fs_info->sb->s_id;
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	va_start(args, fmt);
	vaf.va = &args;

	errstr = btrfs_decode_error(fs_info, errno, nbuf);
	if (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR)
		panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (%s)\n",
			s_id, function, line, &vaf, errstr);

	printk(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (%s)\n",
	       s_id, function, line, &vaf, errstr);
	va_end(args);
	/* Caller calls BUG() */
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}

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static void btrfs_put_super(struct super_block *sb)
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{
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	(void)close_ctree(btrfs_sb(sb)->tree_root);
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	/* FIXME: need to fix VFS to return error? */
	/* AV: return it _where_?  ->put_super() can be triggered by any number
	 * of async events, up to and including delivery of SIGKILL to the
	 * last process that kept it busy.  Or segfault in the aforementioned
	 * process...  Whom would you report that to?
	 */
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}

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enum {
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	Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
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	Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
	Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
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	Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
	Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
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	Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
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	Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache,
	Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
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	Opt_check_integrity, Opt_check_integrity_including_extent_data,
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	Opt_check_integrity_print_mask, Opt_fatal_errors,
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	Opt_err,
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};

static match_table_t tokens = {
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	{Opt_degraded, "degraded"},
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	{Opt_subvol, "subvol=%s"},
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	{Opt_subvolid, "subvolid=%d"},
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	{Opt_device, "device=%s"},
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	{Opt_nodatasum, "nodatasum"},
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	{Opt_nodatacow, "nodatacow"},
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	{Opt_nobarrier, "nobarrier"},
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	{Opt_max_inline, "max_inline=%s"},
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	{Opt_alloc_start, "alloc_start=%s"},
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	{Opt_thread_pool, "thread_pool=%d"},
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	{Opt_compress, "compress"},
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	{Opt_compress_type, "compress=%s"},
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	{Opt_compress_force, "compress-force"},
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	{Opt_compress_force_type, "compress-force=%s"},
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	{Opt_ssd, "ssd"},
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	{Opt_ssd_spread, "ssd_spread"},
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	{Opt_nossd, "nossd"},
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	{Opt_noacl, "noacl"},
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	{Opt_notreelog, "notreelog"},
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	{Opt_flushoncommit, "flushoncommit"},
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	{Opt_ratio, "metadata_ratio=%d"},
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	{Opt_discard, "discard"},
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	{Opt_space_cache, "space_cache"},
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	{Opt_clear_cache, "clear_cache"},
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	{Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
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	{Opt_enospc_debug, "enospc_debug"},
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	{Opt_subvolrootid, "subvolrootid=%d"},
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	{Opt_defrag, "autodefrag"},
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	{Opt_inode_cache, "inode_cache"},
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	{Opt_no_space_cache, "nospace_cache"},
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	{Opt_recovery, "recovery"},
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	{Opt_skip_balance, "skip_balance"},
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	{Opt_check_integrity, "check_int"},
	{Opt_check_integrity_including_extent_data, "check_int_data"},
	{Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
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	{Opt_fatal_errors, "fatal_errors=%s"},
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	{Opt_err, NULL},
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};

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/*
 * Regular mount options parser.  Everything that is needed only when
 * reading in a new superblock is parsed here.
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 * XXX JDM: This needs to be cleaned up for remount.
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 */
int btrfs_parse_options(struct btrfs_root *root, char *options)
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{
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	struct btrfs_fs_info *info = root->fs_info;
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	substring_t args[MAX_OPT_ARGS];
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	char *p, *num, *orig = NULL;
	u64 cache_gen;
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	int intarg;
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	int ret = 0;
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	char *compress_type;
	bool compress_force = false;
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	cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
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	if (cache_gen)
		btrfs_set_opt(info->mount_opt, SPACE_CACHE);

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	if (!options)
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		goto out;
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	/*
	 * strsep changes the string, duplicate it because parse_options
	 * gets called twice
	 */
	options = kstrdup(options, GFP_NOFS);
	if (!options)
		return -ENOMEM;

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	orig = options;
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	while ((p = strsep(&options, ",")) != NULL) {
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		int token;
		if (!*p)
			continue;

		token = match_token(p, tokens, args);
		switch (token) {
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		case Opt_degraded:
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			printk(KERN_INFO "btrfs: allowing degraded mounts\n");
			btrfs_set_opt(info->mount_opt, DEGRADED);
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			break;
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		case Opt_subvol:
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		case Opt_subvolid:
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		case Opt_subvolrootid:
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		case Opt_device:
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			/*
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			 * These are parsed by btrfs_parse_early_options
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			 * and can be happily ignored here.
			 */
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			break;
		case Opt_nodatasum:
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			printk(KERN_INFO "btrfs: setting nodatasum\n");
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			btrfs_set_opt(info->mount_opt, NODATASUM);
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			break;
		case Opt_nodatacow:
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			printk(KERN_INFO "btrfs: setting nodatacow\n");
			btrfs_set_opt(info->mount_opt, NODATACOW);
			btrfs_set_opt(info->mount_opt, NODATASUM);
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			break;
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		case Opt_compress_force:
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		case Opt_compress_force_type:
			compress_force = true;
		case Opt_compress:
		case Opt_compress_type:
			if (token == Opt_compress ||
			    token == Opt_compress_force ||
			    strcmp(args[0].from, "zlib") == 0) {
				compress_type = "zlib";
				info->compress_type = BTRFS_COMPRESS_ZLIB;
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				btrfs_set_opt(info->mount_opt, COMPRESS);
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			} else if (strcmp(args[0].from, "lzo") == 0) {
				compress_type = "lzo";
				info->compress_type = BTRFS_COMPRESS_LZO;
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				btrfs_set_opt(info->mount_opt, COMPRESS);
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				btrfs_set_fs_incompat(info, COMPRESS_LZO);
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			} else if (strncmp(args[0].from, "no", 2) == 0) {
				compress_type = "no";
				info->compress_type = BTRFS_COMPRESS_NONE;
				btrfs_clear_opt(info->mount_opt, COMPRESS);
				btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
				compress_force = false;
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			} else {
				ret = -EINVAL;
				goto out;
			}

			if (compress_force) {
				btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
				pr_info("btrfs: force %s compression\n",
					compress_type);
			} else
				pr_info("btrfs: use %s compression\n",
					compress_type);
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			break;
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		case Opt_ssd:
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			printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
			btrfs_set_opt(info->mount_opt, SSD);
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			break;
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		case Opt_ssd_spread:
			printk(KERN_INFO "btrfs: use spread ssd "
			       "allocation scheme\n");
			btrfs_set_opt(info->mount_opt, SSD);
			btrfs_set_opt(info->mount_opt, SSD_SPREAD);
			break;
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		case Opt_nossd:
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			printk(KERN_INFO "btrfs: not using ssd allocation "
			       "scheme\n");
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			btrfs_set_opt(info->mount_opt, NOSSD);
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			btrfs_clear_opt(info->mount_opt, SSD);
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			btrfs_clear_opt(info->mount_opt, SSD_SPREAD);
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			break;
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		case Opt_nobarrier:
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			printk(KERN_INFO "btrfs: turning off barriers\n");
			btrfs_set_opt(info->mount_opt, NOBARRIER);
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			break;
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		case Opt_thread_pool:
			intarg = 0;
			match_int(&args[0], &intarg);
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			if (intarg)
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				info->thread_pool_size = intarg;
			break;
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		case Opt_max_inline:
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			num = match_strdup(&args[0]);
			if (num) {
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				info->max_inline = memparse(num, NULL);
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				kfree(num);

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				if (info->max_inline) {
					info->max_inline = max_t(u64,
						info->max_inline,
						root->sectorsize);
				}
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				printk(KERN_INFO "btrfs: max_inline at %llu\n",
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					(unsigned long long)info->max_inline);
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			}
			break;
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		case Opt_alloc_start:
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			num = match_strdup(&args[0]);
			if (num) {
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				info->alloc_start = memparse(num, NULL);
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				kfree(num);
				printk(KERN_INFO
					"btrfs: allocations start at %llu\n",
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					(unsigned long long)info->alloc_start);
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			}
			break;
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		case Opt_noacl:
			root->fs_info->sb->s_flags &= ~MS_POSIXACL;
			break;
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		case Opt_notreelog:
			printk(KERN_INFO "btrfs: disabling tree log\n");
			btrfs_set_opt(info->mount_opt, NOTREELOG);
			break;
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		case Opt_flushoncommit:
			printk(KERN_INFO "btrfs: turning on flush-on-commit\n");
			btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT);
			break;
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		case Opt_ratio:
			intarg = 0;
			match_int(&args[0], &intarg);
			if (intarg) {
				info->metadata_ratio = intarg;
				printk(KERN_INFO "btrfs: metadata ratio %d\n",
				       info->metadata_ratio);
			}
			break;
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		case Opt_discard:
			btrfs_set_opt(info->mount_opt, DISCARD);
			break;
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		case Opt_space_cache:
			btrfs_set_opt(info->mount_opt, SPACE_CACHE);
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			break;
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		case Opt_no_space_cache:
			printk(KERN_INFO "btrfs: disabling disk space caching\n");
			btrfs_clear_opt(info->mount_opt, SPACE_CACHE);
			break;
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		case Opt_inode_cache:
			printk(KERN_INFO "btrfs: enabling inode map caching\n");
			btrfs_set_opt(info->mount_opt, INODE_MAP_CACHE);
			break;
535 536 537
		case Opt_clear_cache:
			printk(KERN_INFO "btrfs: force clearing of disk cache\n");
			btrfs_set_opt(info->mount_opt, CLEAR_CACHE);
538
			break;
539 540 541
		case Opt_user_subvol_rm_allowed:
			btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
			break;
542 543 544
		case Opt_enospc_debug:
			btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
			break;
C
Chris Mason 已提交
545 546 547 548
		case Opt_defrag:
			printk(KERN_INFO "btrfs: enabling auto defrag");
			btrfs_set_opt(info->mount_opt, AUTO_DEFRAG);
			break;
C
Chris Mason 已提交
549 550 551 552
		case Opt_recovery:
			printk(KERN_INFO "btrfs: enabling auto recovery");
			btrfs_set_opt(info->mount_opt, RECOVERY);
			break;
553 554 555
		case Opt_skip_balance:
			btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
			break;
556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586
#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
		case Opt_check_integrity_including_extent_data:
			printk(KERN_INFO "btrfs: enabling check integrity"
			       " including extent data\n");
			btrfs_set_opt(info->mount_opt,
				      CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
			btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
			break;
		case Opt_check_integrity:
			printk(KERN_INFO "btrfs: enabling check integrity\n");
			btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
			break;
		case Opt_check_integrity_print_mask:
			intarg = 0;
			match_int(&args[0], &intarg);
			if (intarg) {
				info->check_integrity_print_mask = intarg;
				printk(KERN_INFO "btrfs:"
				       " check_integrity_print_mask 0x%x\n",
				       info->check_integrity_print_mask);
			}
			break;
#else
		case Opt_check_integrity_including_extent_data:
		case Opt_check_integrity:
		case Opt_check_integrity_print_mask:
			printk(KERN_ERR "btrfs: support for check_integrity*"
			       " not compiled in!\n");
			ret = -EINVAL;
			goto out;
#endif
J
Jeff Mahoney 已提交
587 588 589 590 591 592 593 594 595 596 597 598
		case Opt_fatal_errors:
			if (strcmp(args[0].from, "panic") == 0)
				btrfs_set_opt(info->mount_opt,
					      PANIC_ON_FATAL_ERROR);
			else if (strcmp(args[0].from, "bug") == 0)
				btrfs_clear_opt(info->mount_opt,
					      PANIC_ON_FATAL_ERROR);
			else {
				ret = -EINVAL;
				goto out;
			}
			break;
S
Sage Weil 已提交
599 600 601 602 603
		case Opt_err:
			printk(KERN_INFO "btrfs: unrecognized mount option "
			       "'%s'\n", p);
			ret = -EINVAL;
			goto out;
604
		default:
605
			break;
606 607
		}
	}
S
Sage Weil 已提交
608
out:
609 610
	if (!ret && btrfs_test_opt(root, SPACE_CACHE))
		printk(KERN_INFO "btrfs: disk space caching is enabled\n");
611
	kfree(orig);
S
Sage Weil 已提交
612
	return ret;
613 614 615 616 617 618 619 620
}

/*
 * Parse mount options that are required early in the mount process.
 *
 * All other options will be parsed on much later in the mount process and
 * only when we need to allocate a new super block.
 */
621
static int btrfs_parse_early_options(const char *options, fmode_t flags,
622
		void *holder, char **subvol_name, u64 *subvol_objectid,
623
		u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices)
624 625
{
	substring_t args[MAX_OPT_ARGS];
626
	char *device_name, *opts, *orig, *p;
627
	int error = 0;
628
	int intarg;
629 630

	if (!options)
631
		return 0;
632 633 634 635 636 637 638 639

	/*
	 * strsep changes the string, duplicate it because parse_options
	 * gets called twice
	 */
	opts = kstrdup(options, GFP_KERNEL);
	if (!opts)
		return -ENOMEM;
640
	orig = opts;
641 642 643 644 645 646 647 648 649

	while ((p = strsep(&opts, ",")) != NULL) {
		int token;
		if (!*p)
			continue;

		token = match_token(p, tokens, args);
		switch (token) {
		case Opt_subvol:
650
			kfree(*subvol_name);
651 652
			*subvol_name = match_strdup(&args[0]);
			break;
653 654
		case Opt_subvolid:
			intarg = 0;
655 656 657 658 659 660 661 662 663
			error = match_int(&args[0], &intarg);
			if (!error) {
				/* we want the original fs_tree */
				if (!intarg)
					*subvol_objectid =
						BTRFS_FS_TREE_OBJECTID;
				else
					*subvol_objectid = intarg;
			}
664
			break;
665 666 667 668 669 670 671 672 673 674 675 676
		case Opt_subvolrootid:
			intarg = 0;
			error = match_int(&args[0], &intarg);
			if (!error) {
				/* we want the original fs_tree */
				if (!intarg)
					*subvol_rootid =
						BTRFS_FS_TREE_OBJECTID;
				else
					*subvol_rootid = intarg;
			}
			break;
677
		case Opt_device:
678 679 680 681 682 683
			device_name = match_strdup(&args[0]);
			if (!device_name) {
				error = -ENOMEM;
				goto out;
			}
			error = btrfs_scan_one_device(device_name,
684
					flags, holder, fs_devices);
685
			kfree(device_name);
686
			if (error)
687
				goto out;
688
			break;
689 690 691 692 693
		default:
			break;
		}
	}

694
out:
695
	kfree(orig);
696
	return error;
697 698
}

699 700 701
static struct dentry *get_default_root(struct super_block *sb,
				       u64 subvol_objectid)
{
702 703
	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
	struct btrfs_root *root = fs_info->tree_root;
704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732
	struct btrfs_root *new_root;
	struct btrfs_dir_item *di;
	struct btrfs_path *path;
	struct btrfs_key location;
	struct inode *inode;
	u64 dir_id;
	int new = 0;

	/*
	 * We have a specific subvol we want to mount, just setup location and
	 * go look up the root.
	 */
	if (subvol_objectid) {
		location.objectid = subvol_objectid;
		location.type = BTRFS_ROOT_ITEM_KEY;
		location.offset = (u64)-1;
		goto find_root;
	}

	path = btrfs_alloc_path();
	if (!path)
		return ERR_PTR(-ENOMEM);
	path->leave_spinning = 1;

	/*
	 * Find the "default" dir item which points to the root item that we
	 * will mount by default if we haven't been given a specific subvolume
	 * to mount.
	 */
733
	dir_id = btrfs_super_root_dir(fs_info->super_copy);
734
	di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
735 736
	if (IS_ERR(di)) {
		btrfs_free_path(path);
737
		return ERR_CAST(di);
738
	}
739 740 741 742 743 744 745 746
	if (!di) {
		/*
		 * Ok the default dir item isn't there.  This is weird since
		 * it's always been there, but don't freak out, just try and
		 * mount to root most subvolume.
		 */
		btrfs_free_path(path);
		dir_id = BTRFS_FIRST_FREE_OBJECTID;
747
		new_root = fs_info->fs_root;
748 749 750 751 752 753 754
		goto setup_root;
	}

	btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
	btrfs_free_path(path);

find_root:
755
	new_root = btrfs_read_fs_root_no_name(fs_info, &location);
756
	if (IS_ERR(new_root))
J
Julia Lawall 已提交
757
		return ERR_CAST(new_root);
758 759 760 761 762 763 764 765 766 767 768

	if (btrfs_root_refs(&new_root->root_item) == 0)
		return ERR_PTR(-ENOENT);

	dir_id = btrfs_root_dirid(&new_root->root_item);
setup_root:
	location.objectid = dir_id;
	location.type = BTRFS_INODE_ITEM_KEY;
	location.offset = 0;

	inode = btrfs_iget(sb, &location, new_root, &new);
769 770
	if (IS_ERR(inode))
		return ERR_CAST(inode);
771 772 773 774 775 776 777 778 779 780 781

	/*
	 * If we're just mounting the root most subvol put the inode and return
	 * a reference to the dentry.  We will have already gotten a reference
	 * to the inode in btrfs_fill_super so we're good to go.
	 */
	if (!new && sb->s_root->d_inode == inode) {
		iput(inode);
		return dget(sb->s_root);
	}

782
	return d_obtain_alias(inode);
783 784
}

C
Chris Mason 已提交
785
static int btrfs_fill_super(struct super_block *sb,
786
			    struct btrfs_fs_devices *fs_devices,
C
Chris Mason 已提交
787
			    void *data, int silent)
C
Chris Mason 已提交
788
{
C
Chris Mason 已提交
789
	struct inode *inode;
790
	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
791
	struct btrfs_key key;
C
Chris Mason 已提交
792
	int err;
793

C
Chris Mason 已提交
794 795 796
	sb->s_maxbytes = MAX_LFS_FILESIZE;
	sb->s_magic = BTRFS_SUPER_MAGIC;
	sb->s_op = &btrfs_super_ops;
A
Al Viro 已提交
797
	sb->s_d_op = &btrfs_dentry_operations;
B
Balaji Rao 已提交
798
	sb->s_export_op = &btrfs_export_ops;
J
Josef Bacik 已提交
799
	sb->s_xattr = btrfs_xattr_handlers;
C
Chris Mason 已提交
800
	sb->s_time_gran = 1;
C
Chris Mason 已提交
801
#ifdef CONFIG_BTRFS_FS_POSIX_ACL
J
Josef Bacik 已提交
802
	sb->s_flags |= MS_POSIXACL;
803
#endif
804
	sb->s_flags |= MS_I_VERSION;
A
Al Viro 已提交
805 806
	err = open_ctree(sb, fs_devices, (char *)data);
	if (err) {
C
Chris Mason 已提交
807
		printk("btrfs: open_ctree failed\n");
A
Al Viro 已提交
808
		return err;
809 810
	}

811 812 813
	key.objectid = BTRFS_FIRST_FREE_OBJECTID;
	key.type = BTRFS_INODE_ITEM_KEY;
	key.offset = 0;
814
	inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
815 816
	if (IS_ERR(inode)) {
		err = PTR_ERR(inode);
C
Chris Mason 已提交
817
		goto fail_close;
C
Chris Mason 已提交
818 819
	}

820 821
	sb->s_root = d_make_root(inode);
	if (!sb->s_root) {
C
Chris Mason 已提交
822 823
		err = -ENOMEM;
		goto fail_close;
C
Chris Mason 已提交
824
	}
825

C
Chris Mason 已提交
826
	save_mount_options(sb, data);
D
Dan Magenheimer 已提交
827
	cleancache_init_fs(sb);
828
	sb->s_flags |= MS_ACTIVE;
C
Chris Mason 已提交
829
	return 0;
C
Chris Mason 已提交
830 831

fail_close:
832
	close_ctree(fs_info->tree_root);
C
Chris Mason 已提交
833
	return err;
C
Chris Mason 已提交
834 835
}

S
Sage Weil 已提交
836
int btrfs_sync_fs(struct super_block *sb, int wait)
C
Chris Mason 已提交
837 838
{
	struct btrfs_trans_handle *trans;
839 840
	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
	struct btrfs_root *root = fs_info->tree_root;
C
Chris Mason 已提交
841

842 843
	trace_btrfs_sync_fs(wait);

C
Chris Mason 已提交
844
	if (!wait) {
845
		filemap_flush(fs_info->btree_inode->i_mapping);
C
Chris Mason 已提交
846 847
		return 0;
	}
848

Y
Yan, Zheng 已提交
849
	btrfs_wait_ordered_extents(root, 0, 0);
850

851 852 853 854 855 856 857 858
	spin_lock(&fs_info->trans_lock);
	if (!fs_info->running_transaction) {
		spin_unlock(&fs_info->trans_lock);
		return 0;
	}
	spin_unlock(&fs_info->trans_lock);

	trans = btrfs_join_transaction(root);
859 860
	if (IS_ERR(trans))
		return PTR_ERR(trans);
861
	return btrfs_commit_transaction(trans, root);
C
Chris Mason 已提交
862 863
}

864
static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
E
Eric Paris 已提交
865
{
866 867
	struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
	struct btrfs_root *root = info->tree_root;
T
Tsutomu Itoh 已提交
868
	char *compress_type;
E
Eric Paris 已提交
869 870 871 872 873 874 875 876 877 878

	if (btrfs_test_opt(root, DEGRADED))
		seq_puts(seq, ",degraded");
	if (btrfs_test_opt(root, NODATASUM))
		seq_puts(seq, ",nodatasum");
	if (btrfs_test_opt(root, NODATACOW))
		seq_puts(seq, ",nodatacow");
	if (btrfs_test_opt(root, NOBARRIER))
		seq_puts(seq, ",nobarrier");
	if (info->max_inline != 8192 * 1024)
879 880
		seq_printf(seq, ",max_inline=%llu",
			   (unsigned long long)info->max_inline);
E
Eric Paris 已提交
881
	if (info->alloc_start != 0)
882 883
		seq_printf(seq, ",alloc_start=%llu",
			   (unsigned long long)info->alloc_start);
E
Eric Paris 已提交
884 885 886
	if (info->thread_pool_size !=  min_t(unsigned long,
					     num_online_cpus() + 2, 8))
		seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
T
Tsutomu Itoh 已提交
887 888 889 890 891 892 893 894 895 896
	if (btrfs_test_opt(root, COMPRESS)) {
		if (info->compress_type == BTRFS_COMPRESS_ZLIB)
			compress_type = "zlib";
		else
			compress_type = "lzo";
		if (btrfs_test_opt(root, FORCE_COMPRESS))
			seq_printf(seq, ",compress-force=%s", compress_type);
		else
			seq_printf(seq, ",compress=%s", compress_type);
	}
C
Chris Mason 已提交
897 898
	if (btrfs_test_opt(root, NOSSD))
		seq_puts(seq, ",nossd");
899 900 901
	if (btrfs_test_opt(root, SSD_SPREAD))
		seq_puts(seq, ",ssd_spread");
	else if (btrfs_test_opt(root, SSD))
E
Eric Paris 已提交
902
		seq_puts(seq, ",ssd");
S
Sage Weil 已提交
903
	if (btrfs_test_opt(root, NOTREELOG))
904
		seq_puts(seq, ",notreelog");
905
	if (btrfs_test_opt(root, FLUSHONCOMMIT))
906
		seq_puts(seq, ",flushoncommit");
907 908
	if (btrfs_test_opt(root, DISCARD))
		seq_puts(seq, ",discard");
E
Eric Paris 已提交
909 910
	if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
		seq_puts(seq, ",noacl");
T
Tsutomu Itoh 已提交
911 912
	if (btrfs_test_opt(root, SPACE_CACHE))
		seq_puts(seq, ",space_cache");
913
	else
914
		seq_puts(seq, ",nospace_cache");
T
Tsutomu Itoh 已提交
915 916 917 918
	if (btrfs_test_opt(root, CLEAR_CACHE))
		seq_puts(seq, ",clear_cache");
	if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
		seq_puts(seq, ",user_subvol_rm_allowed");
919 920 921 922 923 924
	if (btrfs_test_opt(root, ENOSPC_DEBUG))
		seq_puts(seq, ",enospc_debug");
	if (btrfs_test_opt(root, AUTO_DEFRAG))
		seq_puts(seq, ",autodefrag");
	if (btrfs_test_opt(root, INODE_MAP_CACHE))
		seq_puts(seq, ",inode_cache");
925 926
	if (btrfs_test_opt(root, SKIP_BALANCE))
		seq_puts(seq, ",skip_balance");
J
Jeff Mahoney 已提交
927 928
	if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
		seq_puts(seq, ",fatal_errors=panic");
E
Eric Paris 已提交
929 930 931
	return 0;
}

932
static int btrfs_test_super(struct super_block *s, void *data)
Y
Yan 已提交
933
{
934 935
	struct btrfs_fs_info *p = data;
	struct btrfs_fs_info *fs_info = btrfs_sb(s);
Y
Yan 已提交
936

937
	return fs_info->fs_devices == p->fs_devices;
Y
Yan 已提交
938 939
}

940 941
static int btrfs_set_super(struct super_block *s, void *data)
{
A
Al Viro 已提交
942 943 944 945
	int err = set_anon_super(s, data);
	if (!err)
		s->s_fs_info = data;
	return err;
Y
Yan 已提交
946 947
}

948 949 950 951 952 953 954 955 956 957
/*
 * subvolumes are identified by ino 256
 */
static inline int is_subvolume_inode(struct inode *inode)
{
	if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
		return 1;
	return 0;
}

958 959 960 961 962 963 964
/*
 * This will strip out the subvol=%s argument for an argument string and add
 * subvolid=0 to make sure we get the actual tree root for path walking to the
 * subvol we want.
 */
static char *setup_root_args(char *args)
{
965 966
	unsigned len = strlen(args) + 2 + 1;
	char *src, *dst, *buf;
967 968

	/*
969 970
	 * We need the same args as before, but with this substitution:
	 * s!subvol=[^,]+!subvolid=0!
971
	 *
972 973
	 * Since the replacement string is up to 2 bytes longer than the
	 * original, allocate strlen(args) + 2 + 1 bytes.
974 975
	 */

976
	src = strstr(args, "subvol=");
977
	/* This shouldn't happen, but just in case.. */
978 979 980 981 982
	if (!src)
		return NULL;

	buf = dst = kmalloc(len, GFP_NOFS);
	if (!buf)
983 984 985
		return NULL;

	/*
986 987
	 * If the subvol= arg is not at the start of the string,
	 * copy whatever precedes it into buf.
988
	 */
989 990 991 992
	if (src != args) {
		*src++ = '\0';
		strcpy(buf, args);
		dst += strlen(args);
993 994
	}

995 996
	strcpy(dst, "subvolid=0");
	dst += strlen("subvolid=0");
997 998

	/*
999 1000
	 * If there is a "," after the original subvol=... string,
	 * copy that suffix into our buffer.  Otherwise, we're done.
1001
	 */
1002 1003 1004
	src = strchr(src, ',');
	if (src)
		strcpy(dst, src);
1005

1006
	return buf;
1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024
}

static struct dentry *mount_subvol(const char *subvol_name, int flags,
				   const char *device_name, char *data)
{
	struct dentry *root;
	struct vfsmount *mnt;
	char *newargs;

	newargs = setup_root_args(data);
	if (!newargs)
		return ERR_PTR(-ENOMEM);
	mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
			     newargs);
	kfree(newargs);
	if (IS_ERR(mnt))
		return ERR_CAST(mnt);

A
Al Viro 已提交
1025
	root = mount_subtree(mnt, subvol_name);
1026

A
Al Viro 已提交
1027 1028 1029 1030 1031
	if (!IS_ERR(root) && !is_subvolume_inode(root->d_inode)) {
		struct super_block *s = root->d_sb;
		dput(root);
		root = ERR_PTR(-EINVAL);
		deactivate_locked_super(s);
1032 1033 1034 1035
		printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n",
				subvol_name);
	}

1036 1037
	return root;
}
1038

1039 1040 1041 1042 1043 1044
/*
 * Find a superblock for the given device / mount point.
 *
 * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
 *	  for multiple device setup.  Make sure to keep it in sync.
 */
A
Al Viro 已提交
1045
static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1046
		const char *device_name, void *data)
Y
Yan 已提交
1047 1048 1049 1050
{
	struct block_device *bdev = NULL;
	struct super_block *s;
	struct dentry *root;
1051
	struct btrfs_fs_devices *fs_devices = NULL;
1052
	struct btrfs_fs_info *fs_info = NULL;
1053
	fmode_t mode = FMODE_READ;
1054 1055
	char *subvol_name = NULL;
	u64 subvol_objectid = 0;
1056
	u64 subvol_rootid = 0;
Y
Yan 已提交
1057 1058
	int error = 0;

1059 1060 1061 1062
	if (!(flags & MS_RDONLY))
		mode |= FMODE_WRITE;

	error = btrfs_parse_early_options(data, mode, fs_type,
1063
					  &subvol_name, &subvol_objectid,
1064
					  &subvol_rootid, &fs_devices);
1065 1066
	if (error) {
		kfree(subvol_name);
A
Al Viro 已提交
1067
		return ERR_PTR(error);
1068
	}
1069

1070 1071 1072 1073 1074 1075
	if (subvol_name) {
		root = mount_subvol(subvol_name, flags, device_name, data);
		kfree(subvol_name);
		return root;
	}

1076
	error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1077
	if (error)
1078
		return ERR_PTR(error);
Y
Yan 已提交
1079

1080 1081 1082 1083 1084 1085 1086
	/*
	 * Setup a dummy root and fs_info for test/set super.  This is because
	 * we don't actually fill this stuff out until open_ctree, but we need
	 * it for searching for existing supers, so this lets us do that and
	 * then open_ctree will properly initialize everything later.
	 */
	fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1087 1088 1089
	if (!fs_info)
		return ERR_PTR(-ENOMEM);

1090 1091
	fs_info->fs_devices = fs_devices;

1092 1093 1094 1095
	fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
	fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
	if (!fs_info->super_copy || !fs_info->super_for_commit) {
		error = -ENOMEM;
1096 1097 1098 1099 1100 1101 1102 1103 1104
		goto error_fs_info;
	}

	error = btrfs_open_devices(fs_devices, mode, fs_type);
	if (error)
		goto error_fs_info;

	if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
		error = -EACCES;
1105 1106 1107
		goto error_close_devices;
	}

1108
	bdev = fs_devices->latest_bdev;
D
David Howells 已提交
1109 1110
	s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
		 fs_info);
1111 1112 1113 1114
	if (IS_ERR(s)) {
		error = PTR_ERR(s);
		goto error_close_devices;
	}
Y
Yan 已提交
1115 1116

	if (s->s_root) {
Y
Yan Zheng 已提交
1117
		btrfs_close_devices(fs_devices);
1118
		free_fs_info(fs_info);
1119 1120
		if ((flags ^ s->s_flags) & MS_RDONLY)
			error = -EBUSY;
Y
Yan 已提交
1121 1122 1123 1124
	} else {
		char b[BDEVNAME_SIZE];

		strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
1125
		btrfs_sb(s)->bdev_holder = fs_type;
1126 1127
		error = btrfs_fill_super(s, fs_devices, data,
					 flags & MS_SILENT ? 1 : 0);
Y
Yan 已提交
1128 1129
	}

1130 1131
	root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error);
	if (IS_ERR(root))
1132
		deactivate_locked_super(s);
Y
Yan 已提交
1133

A
Al Viro 已提交
1134
	return root;
Y
Yan 已提交
1135

Y
Yan Zheng 已提交
1136
error_close_devices:
1137
	btrfs_close_devices(fs_devices);
1138
error_fs_info:
1139
	free_fs_info(fs_info);
A
Al Viro 已提交
1140
	return ERR_PTR(error);
Y
Yan 已提交
1141
}
1142

1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176
static void btrfs_set_max_workers(struct btrfs_workers *workers, int new_limit)
{
	spin_lock_irq(&workers->lock);
	workers->max_workers = new_limit;
	spin_unlock_irq(&workers->lock);
}

static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
				     int new_pool_size, int old_pool_size)
{
	if (new_pool_size == old_pool_size)
		return;

	fs_info->thread_pool_size = new_pool_size;

	printk(KERN_INFO "btrfs: resize thread pool %d -> %d\n",
	       old_pool_size, new_pool_size);

	btrfs_set_max_workers(&fs_info->generic_worker, new_pool_size);
	btrfs_set_max_workers(&fs_info->workers, new_pool_size);
	btrfs_set_max_workers(&fs_info->delalloc_workers, new_pool_size);
	btrfs_set_max_workers(&fs_info->submit_workers, new_pool_size);
	btrfs_set_max_workers(&fs_info->caching_workers, new_pool_size);
	btrfs_set_max_workers(&fs_info->fixup_workers, new_pool_size);
	btrfs_set_max_workers(&fs_info->endio_workers, new_pool_size);
	btrfs_set_max_workers(&fs_info->endio_meta_workers, new_pool_size);
	btrfs_set_max_workers(&fs_info->endio_meta_write_workers, new_pool_size);
	btrfs_set_max_workers(&fs_info->endio_write_workers, new_pool_size);
	btrfs_set_max_workers(&fs_info->endio_freespace_worker, new_pool_size);
	btrfs_set_max_workers(&fs_info->delayed_workers, new_pool_size);
	btrfs_set_max_workers(&fs_info->readahead_workers, new_pool_size);
	btrfs_set_max_workers(&fs_info->scrub_workers, new_pool_size);
}

Y
Yan Zheng 已提交
1177 1178
static int btrfs_remount(struct super_block *sb, int *flags, char *data)
{
1179 1180
	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
	struct btrfs_root *root = fs_info->tree_root;
1181 1182 1183 1184 1185 1186 1187
	unsigned old_flags = sb->s_flags;
	unsigned long old_opts = fs_info->mount_opt;
	unsigned long old_compress_type = fs_info->compress_type;
	u64 old_max_inline = fs_info->max_inline;
	u64 old_alloc_start = fs_info->alloc_start;
	int old_thread_pool_size = fs_info->thread_pool_size;
	unsigned int old_metadata_ratio = fs_info->metadata_ratio;
Y
Yan Zheng 已提交
1188 1189
	int ret;

1190
	ret = btrfs_parse_options(root, data);
1191 1192 1193 1194
	if (ret) {
		ret = -EINVAL;
		goto restore;
	}
1195

1196 1197 1198
	btrfs_resize_thread_pool(fs_info,
		fs_info->thread_pool_size, old_thread_pool_size);

Y
Yan Zheng 已提交
1199 1200 1201 1202 1203 1204
	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
		return 0;

	if (*flags & MS_RDONLY) {
		sb->s_flags |= MS_RDONLY;

1205 1206 1207
		ret = btrfs_commit_super(root);
		if (ret)
			goto restore;
Y
Yan Zheng 已提交
1208
	} else {
1209
		if (fs_info->fs_devices->rw_devices == 0) {
1210 1211
			ret = -EACCES;
			goto restore;
1212
		}
Y
Yan Zheng 已提交
1213

1214
		if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1215 1216
			ret = -EINVAL;
			goto restore;
1217
		}
Y
Yan Zheng 已提交
1218

1219
		ret = btrfs_cleanup_fs_roots(fs_info);
1220 1221
		if (ret)
			goto restore;
Y
Yan Zheng 已提交
1222

1223 1224
		/* recover relocation */
		ret = btrfs_recover_relocation(root);
1225 1226
		if (ret)
			goto restore;
Y
Yan Zheng 已提交
1227

1228 1229 1230 1231
		ret = btrfs_resume_balance_async(fs_info);
		if (ret)
			goto restore;

Y
Yan Zheng 已提交
1232 1233 1234 1235
		sb->s_flags &= ~MS_RDONLY;
	}

	return 0;
1236 1237 1238 1239 1240 1241 1242 1243 1244 1245

restore:
	/* We've hit an error - don't reset MS_RDONLY */
	if (sb->s_flags & MS_RDONLY)
		old_flags |= MS_RDONLY;
	sb->s_flags = old_flags;
	fs_info->mount_opt = old_opts;
	fs_info->compress_type = old_compress_type;
	fs_info->max_inline = old_max_inline;
	fs_info->alloc_start = old_alloc_start;
1246 1247
	btrfs_resize_thread_pool(fs_info,
		old_thread_pool_size, fs_info->thread_pool_size);
1248 1249
	fs_info->metadata_ratio = old_metadata_ratio;
	return ret;
Y
Yan Zheng 已提交
1250 1251
}

1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277
/* Used to sort the devices by max_avail(descending sort) */
static int btrfs_cmp_device_free_bytes(const void *dev_info1,
				       const void *dev_info2)
{
	if (((struct btrfs_device_info *)dev_info1)->max_avail >
	    ((struct btrfs_device_info *)dev_info2)->max_avail)
		return -1;
	else if (((struct btrfs_device_info *)dev_info1)->max_avail <
		 ((struct btrfs_device_info *)dev_info2)->max_avail)
		return 1;
	else
	return 0;
}

/*
 * sort the devices by max_avail, in which max free extent size of each device
 * is stored.(Descending Sort)
 */
static inline void btrfs_descending_sort_devices(
					struct btrfs_device_info *devices,
					size_t nr_devices)
{
	sort(devices, nr_devices, sizeof(struct btrfs_device_info),
	     btrfs_cmp_device_free_bytes, NULL);
}

1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292
/*
 * The helper to calc the free space on the devices that can be used to store
 * file data.
 */
static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
{
	struct btrfs_fs_info *fs_info = root->fs_info;
	struct btrfs_device_info *devices_info;
	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
	struct btrfs_device *device;
	u64 skip_space;
	u64 type;
	u64 avail_space;
	u64 used_space;
	u64 min_stripe_size;
1293
	int min_stripes = 1, num_stripes = 1;
1294 1295 1296
	int i = 0, nr_devices;
	int ret;

1297
	nr_devices = fs_info->fs_devices->open_devices;
1298 1299 1300 1301 1302 1303 1304 1305 1306
	BUG_ON(!nr_devices);

	devices_info = kmalloc(sizeof(*devices_info) * nr_devices,
			       GFP_NOFS);
	if (!devices_info)
		return -ENOMEM;

	/* calc min stripe number for data space alloction */
	type = btrfs_get_alloc_profile(root, 1);
1307
	if (type & BTRFS_BLOCK_GROUP_RAID0) {
1308
		min_stripes = 2;
1309 1310
		num_stripes = nr_devices;
	} else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1311
		min_stripes = 2;
1312 1313
		num_stripes = 2;
	} else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1314
		min_stripes = 4;
1315 1316
		num_stripes = 4;
	}
1317 1318 1319 1320 1321 1322

	if (type & BTRFS_BLOCK_GROUP_DUP)
		min_stripe_size = 2 * BTRFS_STRIPE_LEN;
	else
		min_stripe_size = BTRFS_STRIPE_LEN;

1323 1324
	list_for_each_entry(device, &fs_devices->devices, dev_list) {
		if (!device->in_fs_metadata || !device->bdev)
1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384
			continue;

		avail_space = device->total_bytes - device->bytes_used;

		/* align with stripe_len */
		do_div(avail_space, BTRFS_STRIPE_LEN);
		avail_space *= BTRFS_STRIPE_LEN;

		/*
		 * In order to avoid overwritting the superblock on the drive,
		 * btrfs starts at an offset of at least 1MB when doing chunk
		 * allocation.
		 */
		skip_space = 1024 * 1024;

		/* user can set the offset in fs_info->alloc_start. */
		if (fs_info->alloc_start + BTRFS_STRIPE_LEN <=
		    device->total_bytes)
			skip_space = max(fs_info->alloc_start, skip_space);

		/*
		 * btrfs can not use the free space in [0, skip_space - 1],
		 * we must subtract it from the total. In order to implement
		 * it, we account the used space in this range first.
		 */
		ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1,
						     &used_space);
		if (ret) {
			kfree(devices_info);
			return ret;
		}

		/* calc the free space in [0, skip_space - 1] */
		skip_space -= used_space;

		/*
		 * we can use the free space in [0, skip_space - 1], subtract
		 * it from the total.
		 */
		if (avail_space && avail_space >= skip_space)
			avail_space -= skip_space;
		else
			avail_space = 0;

		if (avail_space < min_stripe_size)
			continue;

		devices_info[i].dev = device;
		devices_info[i].max_avail = avail_space;

		i++;
	}

	nr_devices = i;

	btrfs_descending_sort_devices(devices_info, nr_devices);

	i = nr_devices - 1;
	avail_space = 0;
	while (nr_devices >= min_stripes) {
1385 1386 1387
		if (num_stripes > nr_devices)
			num_stripes = nr_devices;

1388 1389 1390 1391
		if (devices_info[i].max_avail >= min_stripe_size) {
			int j;
			u64 alloc_size;

1392
			avail_space += devices_info[i].max_avail * num_stripes;
1393
			alloc_size = devices_info[i].max_avail;
1394
			for (j = i + 1 - num_stripes; j <= i; j++)
1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405
				devices_info[j].max_avail -= alloc_size;
		}
		i--;
		nr_devices--;
	}

	kfree(devices_info);
	*free_bytes = avail_space;
	return 0;
}

C
Chris Mason 已提交
1406 1407
static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
1408 1409 1410
	struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
	struct btrfs_super_block *disk_super = fs_info->super_copy;
	struct list_head *head = &fs_info->space_info;
1411 1412
	struct btrfs_space_info *found;
	u64 total_used = 0;
1413
	u64 total_free_data = 0;
1414
	int bits = dentry->d_sb->s_blocksize_bits;
1415
	__be32 *fsid = (__be32 *)fs_info->fsid;
1416
	int ret;
C
Chris Mason 已提交
1417

1418
	/* holding chunk_muext to avoid allocating new chunks */
1419
	mutex_lock(&fs_info->chunk_mutex);
1420
	rcu_read_lock();
J
Josef Bacik 已提交
1421
	list_for_each_entry_rcu(found, head, list) {
1422 1423 1424 1425 1426 1427
		if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
			total_free_data += found->disk_total - found->disk_used;
			total_free_data -=
				btrfs_account_ro_block_groups_free_space(found);
		}

1428
		total_used += found->disk_used;
J
Josef Bacik 已提交
1429
	}
1430 1431
	rcu_read_unlock();

C
Chris Mason 已提交
1432
	buf->f_namelen = BTRFS_NAME_LEN;
1433
	buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
1434
	buf->f_bfree = buf->f_blocks - (total_used >> bits);
C
Chris Mason 已提交
1435 1436
	buf->f_bsize = dentry->d_sb->s_blocksize;
	buf->f_type = BTRFS_SUPER_MAGIC;
1437
	buf->f_bavail = total_free_data;
1438
	ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
1439
	if (ret) {
1440
		mutex_unlock(&fs_info->chunk_mutex);
1441 1442 1443 1444
		return ret;
	}
	buf->f_bavail += total_free_data;
	buf->f_bavail = buf->f_bavail >> bits;
1445
	mutex_unlock(&fs_info->chunk_mutex);
C
Chris Mason 已提交
1446

1447
	/* We treat it as constant endianness (it doesn't matter _which_)
C
Chris Mason 已提交
1448
	   because we want the fsid to come out the same whether mounted
1449 1450 1451
	   on a big-endian or little-endian host */
	buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
	buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1452 1453 1454 1455
	/* Mask in the root object ID too, to disambiguate subvols */
	buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
	buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;

C
Chris Mason 已提交
1456 1457
	return 0;
}
C
Chris Mason 已提交
1458

A
Al Viro 已提交
1459 1460
static void btrfs_kill_super(struct super_block *sb)
{
1461
	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
A
Al Viro 已提交
1462
	kill_anon_super(sb);
1463
	free_fs_info(fs_info);
A
Al Viro 已提交
1464 1465
}

1466 1467 1468
static struct file_system_type btrfs_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "btrfs",
A
Al Viro 已提交
1469
	.mount		= btrfs_mount,
A
Al Viro 已提交
1470
	.kill_sb	= btrfs_kill_super,
1471 1472
	.fs_flags	= FS_REQUIRES_DEV,
};
1473

C
Chris Mason 已提交
1474 1475 1476
/*
 * used by btrfsctl to scan devices when no FS is mounted
 */
1477 1478 1479 1480 1481
static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
				unsigned long arg)
{
	struct btrfs_ioctl_vol_args *vol;
	struct btrfs_fs_devices *fs_devices;
1482
	int ret = -ENOTTY;
1483

1484 1485 1486
	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

L
Li Zefan 已提交
1487 1488 1489
	vol = memdup_user((void __user *)arg, sizeof(*vol));
	if (IS_ERR(vol))
		return PTR_ERR(vol);
1490

1491 1492
	switch (cmd) {
	case BTRFS_IOC_SCAN_DEV:
1493
		ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1494 1495
					    &btrfs_fs_type, &fs_devices);
		break;
J
Josef Bacik 已提交
1496 1497 1498 1499 1500 1501 1502
	case BTRFS_IOC_DEVICES_READY:
		ret = btrfs_scan_one_device(vol->name, FMODE_READ,
					    &btrfs_fs_type, &fs_devices);
		if (ret)
			break;
		ret = !(fs_devices->num_devices == fs_devices->total_devices);
		break;
1503
	}
L
Li Zefan 已提交
1504

1505
	kfree(vol);
L
Linda Knippers 已提交
1506
	return ret;
1507 1508
}

1509
static int btrfs_freeze(struct super_block *sb)
Y
Yan 已提交
1510
{
1511 1512 1513
	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
	mutex_lock(&fs_info->transaction_kthread_mutex);
	mutex_lock(&fs_info->cleaner_mutex);
1514
	return 0;
Y
Yan 已提交
1515 1516
}

1517
static int btrfs_unfreeze(struct super_block *sb)
Y
Yan 已提交
1518
{
1519 1520 1521
	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
	mutex_unlock(&fs_info->cleaner_mutex);
	mutex_unlock(&fs_info->transaction_kthread_mutex);
1522
	return 0;
Y
Yan 已提交
1523
}
1524

J
Josef Bacik 已提交
1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537
static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
{
	struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
	struct btrfs_fs_devices *cur_devices;
	struct btrfs_device *dev, *first_dev = NULL;
	struct list_head *head;
	struct rcu_string *name;

	mutex_lock(&fs_info->fs_devices->device_list_mutex);
	cur_devices = fs_info->fs_devices;
	while (cur_devices) {
		head = &cur_devices->devices;
		list_for_each_entry(dev, head, dev_list) {
1538 1539
			if (dev->missing)
				continue;
J
Josef Bacik 已提交
1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557
			if (!first_dev || dev->devid < first_dev->devid)
				first_dev = dev;
		}
		cur_devices = cur_devices->seed;
	}

	if (first_dev) {
		rcu_read_lock();
		name = rcu_dereference(first_dev->name);
		seq_escape(m, name->str, " \t\n\\");
		rcu_read_unlock();
	} else {
		WARN_ON(1);
	}
	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
	return 0;
}

1558
static const struct super_operations btrfs_super_ops = {
1559
	.drop_inode	= btrfs_drop_inode,
A
Al Viro 已提交
1560
	.evict_inode	= btrfs_evict_inode,
C
Chris Mason 已提交
1561
	.put_super	= btrfs_put_super,
1562
	.sync_fs	= btrfs_sync_fs,
E
Eric Paris 已提交
1563
	.show_options	= btrfs_show_options,
J
Josef Bacik 已提交
1564
	.show_devname	= btrfs_show_devname,
C
Chris Mason 已提交
1565
	.write_inode	= btrfs_write_inode,
C
Chris Mason 已提交
1566 1567
	.alloc_inode	= btrfs_alloc_inode,
	.destroy_inode	= btrfs_destroy_inode,
C
Chris Mason 已提交
1568
	.statfs		= btrfs_statfs,
Y
Yan Zheng 已提交
1569
	.remount_fs	= btrfs_remount,
1570 1571
	.freeze_fs	= btrfs_freeze,
	.unfreeze_fs	= btrfs_unfreeze,
C
Chris Mason 已提交
1572
};
1573 1574 1575 1576 1577

static const struct file_operations btrfs_ctl_fops = {
	.unlocked_ioctl	 = btrfs_control_ioctl,
	.compat_ioctl = btrfs_control_ioctl,
	.owner	 = THIS_MODULE,
1578
	.llseek = noop_llseek,
1579 1580 1581
};

static struct miscdevice btrfs_misc = {
1582
	.minor		= BTRFS_MINOR,
1583 1584 1585 1586
	.name		= "btrfs-control",
	.fops		= &btrfs_ctl_fops
};

1587 1588 1589
MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
MODULE_ALIAS("devname:btrfs-control");

1590 1591 1592 1593 1594
static int btrfs_interface_init(void)
{
	return misc_register(&btrfs_misc);
}

1595
static void btrfs_interface_exit(void)
1596 1597
{
	if (misc_deregister(&btrfs_misc) < 0)
C
Chris Mason 已提交
1598
		printk(KERN_INFO "misc_deregister failed for control device");
1599 1600
}

1601 1602
static int __init init_btrfs_fs(void)
{
C
Chris Mason 已提交
1603
	int err;
1604 1605 1606 1607 1608

	err = btrfs_init_sysfs();
	if (err)
		return err;

1609
	btrfs_init_compress();
1610

1611 1612 1613 1614
	err = btrfs_init_cachep();
	if (err)
		goto free_compress;

1615
	err = extent_io_init();
1616 1617 1618
	if (err)
		goto free_cachep;

1619 1620 1621 1622
	err = extent_map_init();
	if (err)
		goto free_extent_io;

1623
	err = ordered_data_init();
1624 1625
	if (err)
		goto free_extent_map;
C
Chris Mason 已提交
1626

1627 1628 1629 1630
	err = btrfs_delayed_inode_init();
	if (err)
		goto free_ordered_data;

1631 1632 1633 1634
	err = btrfs_interface_init();
	if (err)
		goto free_delayed_inode;

1635 1636 1637
	err = register_filesystem(&btrfs_fs_type);
	if (err)
		goto unregister_ioctl;
1638

1639 1640
	btrfs_init_lockdep();

1641
	printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
1642 1643
	return 0;

1644 1645
unregister_ioctl:
	btrfs_interface_exit();
1646 1647
free_delayed_inode:
	btrfs_delayed_inode_exit();
1648 1649
free_ordered_data:
	ordered_data_exit();
1650 1651
free_extent_map:
	extent_map_exit();
1652 1653
free_extent_io:
	extent_io_exit();
1654 1655
free_cachep:
	btrfs_destroy_cachep();
1656 1657
free_compress:
	btrfs_exit_compress();
1658 1659
	btrfs_exit_sysfs();
	return err;
1660 1661 1662 1663
}

static void __exit exit_btrfs_fs(void)
{
C
Chris Mason 已提交
1664
	btrfs_destroy_cachep();
1665
	btrfs_delayed_inode_exit();
1666
	ordered_data_exit();
1667
	extent_map_exit();
1668
	extent_io_exit();
1669
	btrfs_interface_exit();
1670
	unregister_filesystem(&btrfs_fs_type);
1671
	btrfs_exit_sysfs();
1672
	btrfs_cleanup_fs_uuids();
1673
	btrfs_exit_compress();
1674 1675 1676 1677 1678 1679
}

module_init(init_btrfs_fs)
module_exit(exit_btrfs_fs)

MODULE_LICENSE("GPL");