super.c 42.3 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;
}

/* NOTE:
 *	We move write_super stuff at umount in order to avoid deadlock
 *	for umount hold all lock.
 */
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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	}
}

/*
 * __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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const char *logtypes[] = {
	"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];

	va_start(args, fmt);

	if (fmt[0] == '<' && isdigit(fmt[1]) && fmt[2] == '>') {
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		memcpy(lvl, fmt, 3);
		lvl[3] = '\0';
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		fmt += 3;
		type = logtypes[fmt[1] - '0'];
	} else
		*lvl = '\0';

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

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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);
			} 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;
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		case Opt_clear_cache:
			printk(KERN_INFO "btrfs: force clearing of disk cache\n");
			btrfs_set_opt(info->mount_opt, CLEAR_CACHE);
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			break;
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		case Opt_user_subvol_rm_allowed:
			btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
			break;
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		case Opt_enospc_debug:
			btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
			break;
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		case Opt_defrag:
			printk(KERN_INFO "btrfs: enabling auto defrag");
			btrfs_set_opt(info->mount_opt, AUTO_DEFRAG);
			break;
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		case Opt_recovery:
			printk(KERN_INFO "btrfs: enabling auto recovery");
			btrfs_set_opt(info->mount_opt, RECOVERY);
			break;
527 528 529
		case Opt_skip_balance:
			btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
			break;
530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560
#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
561 562 563 564 565 566 567 568 569 570 571 572
		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
573 574 575 576 577
		case Opt_err:
			printk(KERN_INFO "btrfs: unrecognized mount option "
			       "'%s'\n", p);
			ret = -EINVAL;
			goto out;
578
		default:
579
			break;
580 581
		}
	}
S
Sage Weil 已提交
582
out:
583 584
	if (!ret && btrfs_test_opt(root, SPACE_CACHE))
		printk(KERN_INFO "btrfs: disk space caching is enabled\n");
585
	kfree(orig);
S
Sage Weil 已提交
586
	return ret;
587 588 589 590 591 592 593 594
}

/*
 * 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.
 */
595
static int btrfs_parse_early_options(const char *options, fmode_t flags,
596
		void *holder, char **subvol_name, u64 *subvol_objectid,
597
		u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices)
598 599
{
	substring_t args[MAX_OPT_ARGS];
600
	char *device_name, *opts, *orig, *p;
601
	int error = 0;
602
	int intarg;
603 604

	if (!options)
605
		return 0;
606 607 608 609 610 611 612 613

	/*
	 * strsep changes the string, duplicate it because parse_options
	 * gets called twice
	 */
	opts = kstrdup(options, GFP_KERNEL);
	if (!opts)
		return -ENOMEM;
614
	orig = opts;
615 616 617 618 619 620 621 622 623

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

		token = match_token(p, tokens, args);
		switch (token) {
		case Opt_subvol:
624
			kfree(*subvol_name);
625 626
			*subvol_name = match_strdup(&args[0]);
			break;
627 628
		case Opt_subvolid:
			intarg = 0;
629 630 631 632 633 634 635 636 637
			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;
			}
638
			break;
639 640 641 642 643 644 645 646 647 648 649 650
		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;
651
		case Opt_device:
652 653 654 655 656 657
			device_name = match_strdup(&args[0]);
			if (!device_name) {
				error = -ENOMEM;
				goto out;
			}
			error = btrfs_scan_one_device(device_name,
658
					flags, holder, fs_devices);
659
			kfree(device_name);
660
			if (error)
661
				goto out;
662
			break;
663 664 665 666 667
		default:
			break;
		}
	}

668
out:
669
	kfree(orig);
670
	return error;
671 672
}

673 674 675
static struct dentry *get_default_root(struct super_block *sb,
				       u64 subvol_objectid)
{
676 677
	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
	struct btrfs_root *root = fs_info->tree_root;
678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706
	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.
	 */
707
	dir_id = btrfs_super_root_dir(fs_info->super_copy);
708
	di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
709 710
	if (IS_ERR(di)) {
		btrfs_free_path(path);
711
		return ERR_CAST(di);
712
	}
713 714 715 716 717 718 719 720
	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;
721
		new_root = fs_info->fs_root;
722 723 724 725 726 727 728
		goto setup_root;
	}

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

find_root:
729
	new_root = btrfs_read_fs_root_no_name(fs_info, &location);
730
	if (IS_ERR(new_root))
J
Julia Lawall 已提交
731
		return ERR_CAST(new_root);
732 733 734 735 736 737 738 739 740 741 742

	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);
743 744
	if (IS_ERR(inode))
		return ERR_CAST(inode);
745 746 747 748 749 750 751 752 753 754 755

	/*
	 * 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);
	}

756
	return d_obtain_alias(inode);
757 758
}

C
Chris Mason 已提交
759
static int btrfs_fill_super(struct super_block *sb,
760
			    struct btrfs_fs_devices *fs_devices,
C
Chris Mason 已提交
761
			    void *data, int silent)
C
Chris Mason 已提交
762
{
C
Chris Mason 已提交
763
	struct inode *inode;
764
	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
765
	struct btrfs_key key;
C
Chris Mason 已提交
766
	int err;
767

C
Chris Mason 已提交
768 769 770
	sb->s_maxbytes = MAX_LFS_FILESIZE;
	sb->s_magic = BTRFS_SUPER_MAGIC;
	sb->s_op = &btrfs_super_ops;
A
Al Viro 已提交
771
	sb->s_d_op = &btrfs_dentry_operations;
B
Balaji Rao 已提交
772
	sb->s_export_op = &btrfs_export_ops;
J
Josef Bacik 已提交
773
	sb->s_xattr = btrfs_xattr_handlers;
C
Chris Mason 已提交
774
	sb->s_time_gran = 1;
C
Chris Mason 已提交
775
#ifdef CONFIG_BTRFS_FS_POSIX_ACL
J
Josef Bacik 已提交
776
	sb->s_flags |= MS_POSIXACL;
777
#endif
778
	sb->s_flags |= MS_I_VERSION;
A
Al Viro 已提交
779 780
	err = open_ctree(sb, fs_devices, (char *)data);
	if (err) {
C
Chris Mason 已提交
781
		printk("btrfs: open_ctree failed\n");
A
Al Viro 已提交
782
		return err;
783 784
	}

785 786 787
	key.objectid = BTRFS_FIRST_FREE_OBJECTID;
	key.type = BTRFS_INODE_ITEM_KEY;
	key.offset = 0;
788
	inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
789 790
	if (IS_ERR(inode)) {
		err = PTR_ERR(inode);
C
Chris Mason 已提交
791
		goto fail_close;
C
Chris Mason 已提交
792 793
	}

794 795
	sb->s_root = d_make_root(inode);
	if (!sb->s_root) {
C
Chris Mason 已提交
796 797
		err = -ENOMEM;
		goto fail_close;
C
Chris Mason 已提交
798
	}
799

C
Chris Mason 已提交
800
	save_mount_options(sb, data);
D
Dan Magenheimer 已提交
801
	cleancache_init_fs(sb);
802
	sb->s_flags |= MS_ACTIVE;
C
Chris Mason 已提交
803
	return 0;
C
Chris Mason 已提交
804 805

fail_close:
806
	close_ctree(fs_info->tree_root);
C
Chris Mason 已提交
807
	return err;
C
Chris Mason 已提交
808 809
}

S
Sage Weil 已提交
810
int btrfs_sync_fs(struct super_block *sb, int wait)
C
Chris Mason 已提交
811 812
{
	struct btrfs_trans_handle *trans;
813 814
	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
	struct btrfs_root *root = fs_info->tree_root;
C
Chris Mason 已提交
815
	int ret;
C
Chris Mason 已提交
816

817 818
	trace_btrfs_sync_fs(wait);

C
Chris Mason 已提交
819
	if (!wait) {
820
		filemap_flush(fs_info->btree_inode->i_mapping);
C
Chris Mason 已提交
821 822
		return 0;
	}
823

Y
Yan, Zheng 已提交
824
	btrfs_wait_ordered_extents(root, 0, 0);
825

826
	trans = btrfs_start_transaction(root, 0);
827 828
	if (IS_ERR(trans))
		return PTR_ERR(trans);
C
Chris Mason 已提交
829
	ret = btrfs_commit_transaction(trans, root);
830
	return ret;
C
Chris Mason 已提交
831 832
}

833
static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
E
Eric Paris 已提交
834
{
835 836
	struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
	struct btrfs_root *root = info->tree_root;
T
Tsutomu Itoh 已提交
837
	char *compress_type;
E
Eric Paris 已提交
838 839 840 841 842 843 844 845 846 847

	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)
848 849
		seq_printf(seq, ",max_inline=%llu",
			   (unsigned long long)info->max_inline);
E
Eric Paris 已提交
850
	if (info->alloc_start != 0)
851 852
		seq_printf(seq, ",alloc_start=%llu",
			   (unsigned long long)info->alloc_start);
E
Eric Paris 已提交
853 854 855
	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
856 857 858 859 860 861 862 863 864 865
	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
866 867
	if (btrfs_test_opt(root, NOSSD))
		seq_puts(seq, ",nossd");
868 869 870
	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
871
		seq_puts(seq, ",ssd");
S
Sage Weil 已提交
872
	if (btrfs_test_opt(root, NOTREELOG))
873
		seq_puts(seq, ",notreelog");
874
	if (btrfs_test_opt(root, FLUSHONCOMMIT))
875
		seq_puts(seq, ",flushoncommit");
876 877
	if (btrfs_test_opt(root, DISCARD))
		seq_puts(seq, ",discard");
E
Eric Paris 已提交
878 879
	if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
		seq_puts(seq, ",noacl");
T
Tsutomu Itoh 已提交
880 881
	if (btrfs_test_opt(root, SPACE_CACHE))
		seq_puts(seq, ",space_cache");
882
	else
883
		seq_puts(seq, ",nospace_cache");
T
Tsutomu Itoh 已提交
884 885 886 887
	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");
888 889 890 891 892 893
	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");
894 895
	if (btrfs_test_opt(root, SKIP_BALANCE))
		seq_puts(seq, ",skip_balance");
J
Jeff Mahoney 已提交
896 897
	if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
		seq_puts(seq, ",fatal_errors=panic");
E
Eric Paris 已提交
898 899 900
	return 0;
}

901
static int btrfs_test_super(struct super_block *s, void *data)
Y
Yan 已提交
902
{
903 904
	struct btrfs_fs_info *p = data;
	struct btrfs_fs_info *fs_info = btrfs_sb(s);
Y
Yan 已提交
905

906
	return fs_info->fs_devices == p->fs_devices;
Y
Yan 已提交
907 908
}

909 910
static int btrfs_set_super(struct super_block *s, void *data)
{
A
Al Viro 已提交
911 912 913 914
	int err = set_anon_super(s, data);
	if (!err)
		s->s_fs_info = data;
	return err;
Y
Yan 已提交
915 916
}

917 918 919 920 921 922 923 924 925 926
/*
 * 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;
}

927 928 929 930 931 932 933
/*
 * 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)
{
934 935
	unsigned len = strlen(args) + 2 + 1;
	char *src, *dst, *buf;
936 937

	/*
938 939
	 * We need the same args as before, but with this substitution:
	 * s!subvol=[^,]+!subvolid=0!
940
	 *
941 942
	 * Since the replacement string is up to 2 bytes longer than the
	 * original, allocate strlen(args) + 2 + 1 bytes.
943 944
	 */

945
	src = strstr(args, "subvol=");
946
	/* This shouldn't happen, but just in case.. */
947 948 949 950 951
	if (!src)
		return NULL;

	buf = dst = kmalloc(len, GFP_NOFS);
	if (!buf)
952 953 954
		return NULL;

	/*
955 956
	 * If the subvol= arg is not at the start of the string,
	 * copy whatever precedes it into buf.
957
	 */
958 959 960 961
	if (src != args) {
		*src++ = '\0';
		strcpy(buf, args);
		dst += strlen(args);
962 963
	}

964 965
	strcpy(dst, "subvolid=0");
	dst += strlen("subvolid=0");
966 967

	/*
968 969
	 * If there is a "," after the original subvol=... string,
	 * copy that suffix into our buffer.  Otherwise, we're done.
970
	 */
971 972 973
	src = strchr(src, ',');
	if (src)
		strcpy(dst, src);
974

975
	return buf;
976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993
}

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
994
	root = mount_subtree(mnt, subvol_name);
995

A
Al Viro 已提交
996 997 998 999 1000
	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);
1001 1002 1003 1004
		printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n",
				subvol_name);
	}

1005 1006
	return root;
}
1007

1008 1009 1010 1011 1012 1013
/*
 * 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
1014
static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1015
		const char *device_name, void *data)
Y
Yan 已提交
1016 1017 1018 1019
{
	struct block_device *bdev = NULL;
	struct super_block *s;
	struct dentry *root;
1020
	struct btrfs_fs_devices *fs_devices = NULL;
1021
	struct btrfs_fs_info *fs_info = NULL;
1022
	fmode_t mode = FMODE_READ;
1023 1024
	char *subvol_name = NULL;
	u64 subvol_objectid = 0;
1025
	u64 subvol_rootid = 0;
Y
Yan 已提交
1026 1027
	int error = 0;

1028 1029 1030 1031
	if (!(flags & MS_RDONLY))
		mode |= FMODE_WRITE;

	error = btrfs_parse_early_options(data, mode, fs_type,
1032
					  &subvol_name, &subvol_objectid,
1033
					  &subvol_rootid, &fs_devices);
1034 1035
	if (error) {
		kfree(subvol_name);
A
Al Viro 已提交
1036
		return ERR_PTR(error);
1037
	}
1038

1039 1040 1041 1042 1043 1044
	if (subvol_name) {
		root = mount_subvol(subvol_name, flags, device_name, data);
		kfree(subvol_name);
		return root;
	}

1045
	error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1046
	if (error)
1047
		return ERR_PTR(error);
Y
Yan 已提交
1048

1049 1050 1051 1052 1053 1054 1055
	/*
	 * 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);
1056 1057 1058
	if (!fs_info)
		return ERR_PTR(-ENOMEM);

1059 1060
	fs_info->fs_devices = fs_devices;

1061 1062 1063 1064
	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;
1065 1066 1067 1068 1069 1070 1071 1072 1073
		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;
1074 1075 1076
		goto error_close_devices;
	}

1077
	bdev = fs_devices->latest_bdev;
1078
	s = sget(fs_type, btrfs_test_super, btrfs_set_super, fs_info);
1079 1080 1081 1082
	if (IS_ERR(s)) {
		error = PTR_ERR(s);
		goto error_close_devices;
	}
Y
Yan 已提交
1083 1084

	if (s->s_root) {
Y
Yan Zheng 已提交
1085
		btrfs_close_devices(fs_devices);
1086
		free_fs_info(fs_info);
1087 1088
		if ((flags ^ s->s_flags) & MS_RDONLY)
			error = -EBUSY;
Y
Yan 已提交
1089 1090 1091
	} else {
		char b[BDEVNAME_SIZE];

A
Al Viro 已提交
1092
		s->s_flags = flags | MS_NOSEC;
Y
Yan 已提交
1093
		strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
1094
		btrfs_sb(s)->bdev_holder = fs_type;
1095 1096
		error = btrfs_fill_super(s, fs_devices, data,
					 flags & MS_SILENT ? 1 : 0);
Y
Yan 已提交
1097 1098
	}

1099 1100
	root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error);
	if (IS_ERR(root))
1101
		deactivate_locked_super(s);
Y
Yan 已提交
1102

A
Al Viro 已提交
1103
	return root;
Y
Yan 已提交
1104

Y
Yan Zheng 已提交
1105
error_close_devices:
1106
	btrfs_close_devices(fs_devices);
1107
error_fs_info:
1108
	free_fs_info(fs_info);
A
Al Viro 已提交
1109
	return ERR_PTR(error);
Y
Yan 已提交
1110
}
1111

1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145
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
1146 1147
static int btrfs_remount(struct super_block *sb, int *flags, char *data)
{
1148 1149
	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
	struct btrfs_root *root = fs_info->tree_root;
1150 1151 1152 1153 1154 1155 1156
	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
1157 1158
	int ret;

1159
	ret = btrfs_parse_options(root, data);
1160 1161 1162 1163
	if (ret) {
		ret = -EINVAL;
		goto restore;
	}
1164

1165 1166 1167
	btrfs_resize_thread_pool(fs_info,
		fs_info->thread_pool_size, old_thread_pool_size);

Y
Yan Zheng 已提交
1168 1169 1170 1171 1172 1173
	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
		return 0;

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

1174 1175 1176
		ret = btrfs_commit_super(root);
		if (ret)
			goto restore;
Y
Yan Zheng 已提交
1177
	} else {
1178
		if (fs_info->fs_devices->rw_devices == 0) {
1179 1180
			ret = -EACCES;
			goto restore;
1181
		}
Y
Yan Zheng 已提交
1182

1183
		if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1184 1185
			ret = -EINVAL;
			goto restore;
1186
		}
Y
Yan Zheng 已提交
1187

1188
		ret = btrfs_cleanup_fs_roots(fs_info);
1189 1190
		if (ret)
			goto restore;
Y
Yan Zheng 已提交
1191

1192 1193
		/* recover relocation */
		ret = btrfs_recover_relocation(root);
1194 1195
		if (ret)
			goto restore;
Y
Yan Zheng 已提交
1196

1197 1198 1199 1200
		ret = btrfs_resume_balance_async(fs_info);
		if (ret)
			goto restore;

Y
Yan Zheng 已提交
1201 1202 1203 1204
		sb->s_flags &= ~MS_RDONLY;
	}

	return 0;
1205 1206 1207 1208 1209 1210 1211 1212 1213 1214

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;
1215 1216
	btrfs_resize_thread_pool(fs_info,
		old_thread_pool_size, fs_info->thread_pool_size);
1217 1218
	fs_info->metadata_ratio = old_metadata_ratio;
	return ret;
Y
Yan Zheng 已提交
1219 1220
}

1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246
/* 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);
}

1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261
/*
 * 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;
1262
	int min_stripes = 1, num_stripes = 1;
1263 1264 1265
	int i = 0, nr_devices;
	int ret;

1266
	nr_devices = fs_info->fs_devices->open_devices;
1267 1268 1269 1270 1271 1272 1273 1274 1275
	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);
1276
	if (type & BTRFS_BLOCK_GROUP_RAID0) {
1277
		min_stripes = 2;
1278 1279
		num_stripes = nr_devices;
	} else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1280
		min_stripes = 2;
1281 1282
		num_stripes = 2;
	} else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1283
		min_stripes = 4;
1284 1285
		num_stripes = 4;
	}
1286 1287 1288 1289 1290 1291

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

1292 1293
	list_for_each_entry(device, &fs_devices->devices, dev_list) {
		if (!device->in_fs_metadata || !device->bdev)
1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 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
			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) {
1354 1355 1356
		if (num_stripes > nr_devices)
			num_stripes = nr_devices;

1357 1358 1359 1360
		if (devices_info[i].max_avail >= min_stripe_size) {
			int j;
			u64 alloc_size;

1361
			avail_space += devices_info[i].max_avail * num_stripes;
1362
			alloc_size = devices_info[i].max_avail;
1363
			for (j = i + 1 - num_stripes; j <= i; j++)
1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374
				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
1375 1376
static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
1377 1378 1379
	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;
1380 1381
	struct btrfs_space_info *found;
	u64 total_used = 0;
1382
	u64 total_free_data = 0;
1383
	int bits = dentry->d_sb->s_blocksize_bits;
1384
	__be32 *fsid = (__be32 *)fs_info->fsid;
1385
	int ret;
C
Chris Mason 已提交
1386

1387
	/* holding chunk_muext to avoid allocating new chunks */
1388
	mutex_lock(&fs_info->chunk_mutex);
1389
	rcu_read_lock();
J
Josef Bacik 已提交
1390
	list_for_each_entry_rcu(found, head, list) {
1391 1392 1393 1394 1395 1396
		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);
		}

1397
		total_used += found->disk_used;
J
Josef Bacik 已提交
1398
	}
1399 1400
	rcu_read_unlock();

C
Chris Mason 已提交
1401
	buf->f_namelen = BTRFS_NAME_LEN;
1402
	buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
1403
	buf->f_bfree = buf->f_blocks - (total_used >> bits);
C
Chris Mason 已提交
1404 1405
	buf->f_bsize = dentry->d_sb->s_blocksize;
	buf->f_type = BTRFS_SUPER_MAGIC;
1406
	buf->f_bavail = total_free_data;
1407
	ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
1408
	if (ret) {
1409
		mutex_unlock(&fs_info->chunk_mutex);
1410 1411 1412 1413
		return ret;
	}
	buf->f_bavail += total_free_data;
	buf->f_bavail = buf->f_bavail >> bits;
1414
	mutex_unlock(&fs_info->chunk_mutex);
C
Chris Mason 已提交
1415

1416
	/* We treat it as constant endianness (it doesn't matter _which_)
C
Chris Mason 已提交
1417
	   because we want the fsid to come out the same whether mounted
1418 1419 1420
	   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]);
1421 1422 1423 1424
	/* 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
1425 1426
	return 0;
}
C
Chris Mason 已提交
1427

A
Al Viro 已提交
1428 1429
static void btrfs_kill_super(struct super_block *sb)
{
1430
	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
A
Al Viro 已提交
1431
	kill_anon_super(sb);
1432
	free_fs_info(fs_info);
A
Al Viro 已提交
1433 1434
}

1435 1436 1437
static struct file_system_type btrfs_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "btrfs",
A
Al Viro 已提交
1438
	.mount		= btrfs_mount,
A
Al Viro 已提交
1439
	.kill_sb	= btrfs_kill_super,
1440 1441
	.fs_flags	= FS_REQUIRES_DEV,
};
1442

C
Chris Mason 已提交
1443 1444 1445
/*
 * used by btrfsctl to scan devices when no FS is mounted
 */
1446 1447 1448 1449 1450
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;
1451
	int ret = -ENOTTY;
1452

1453 1454 1455
	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

L
Li Zefan 已提交
1456 1457 1458
	vol = memdup_user((void __user *)arg, sizeof(*vol));
	if (IS_ERR(vol))
		return PTR_ERR(vol);
1459

1460 1461
	switch (cmd) {
	case BTRFS_IOC_SCAN_DEV:
1462
		ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1463 1464 1465
					    &btrfs_fs_type, &fs_devices);
		break;
	}
L
Li Zefan 已提交
1466

1467
	kfree(vol);
L
Linda Knippers 已提交
1468
	return ret;
1469 1470
}

1471
static int btrfs_freeze(struct super_block *sb)
Y
Yan 已提交
1472
{
1473 1474 1475
	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
	mutex_lock(&fs_info->transaction_kthread_mutex);
	mutex_lock(&fs_info->cleaner_mutex);
1476
	return 0;
Y
Yan 已提交
1477 1478
}

1479
static int btrfs_unfreeze(struct super_block *sb)
Y
Yan 已提交
1480
{
1481 1482 1483
	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
	mutex_unlock(&fs_info->cleaner_mutex);
	mutex_unlock(&fs_info->transaction_kthread_mutex);
1484
	return 0;
Y
Yan 已提交
1485
}
1486

J
Josef Bacik 已提交
1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517
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) {
			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;
}

1518
static const struct super_operations btrfs_super_ops = {
1519
	.drop_inode	= btrfs_drop_inode,
A
Al Viro 已提交
1520
	.evict_inode	= btrfs_evict_inode,
C
Chris Mason 已提交
1521
	.put_super	= btrfs_put_super,
1522
	.sync_fs	= btrfs_sync_fs,
E
Eric Paris 已提交
1523
	.show_options	= btrfs_show_options,
J
Josef Bacik 已提交
1524
	.show_devname	= btrfs_show_devname,
C
Chris Mason 已提交
1525
	.write_inode	= btrfs_write_inode,
C
Chris Mason 已提交
1526 1527
	.alloc_inode	= btrfs_alloc_inode,
	.destroy_inode	= btrfs_destroy_inode,
C
Chris Mason 已提交
1528
	.statfs		= btrfs_statfs,
Y
Yan Zheng 已提交
1529
	.remount_fs	= btrfs_remount,
1530 1531
	.freeze_fs	= btrfs_freeze,
	.unfreeze_fs	= btrfs_unfreeze,
C
Chris Mason 已提交
1532
};
1533 1534 1535 1536 1537

static const struct file_operations btrfs_ctl_fops = {
	.unlocked_ioctl	 = btrfs_control_ioctl,
	.compat_ioctl = btrfs_control_ioctl,
	.owner	 = THIS_MODULE,
1538
	.llseek = noop_llseek,
1539 1540 1541
};

static struct miscdevice btrfs_misc = {
1542
	.minor		= BTRFS_MINOR,
1543 1544 1545 1546
	.name		= "btrfs-control",
	.fops		= &btrfs_ctl_fops
};

1547 1548 1549
MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
MODULE_ALIAS("devname:btrfs-control");

1550 1551 1552 1553 1554
static int btrfs_interface_init(void)
{
	return misc_register(&btrfs_misc);
}

1555
static void btrfs_interface_exit(void)
1556 1557
{
	if (misc_deregister(&btrfs_misc) < 0)
C
Chris Mason 已提交
1558
		printk(KERN_INFO "misc_deregister failed for control device");
1559 1560
}

1561 1562
static int __init init_btrfs_fs(void)
{
C
Chris Mason 已提交
1563
	int err;
1564 1565 1566 1567 1568

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

1569
	btrfs_init_compress();
1570

1571 1572 1573 1574
	err = btrfs_init_cachep();
	if (err)
		goto free_compress;

1575
	err = extent_io_init();
1576 1577 1578
	if (err)
		goto free_cachep;

1579 1580 1581 1582
	err = extent_map_init();
	if (err)
		goto free_extent_io;

1583
	err = btrfs_delayed_inode_init();
1584 1585
	if (err)
		goto free_extent_map;
C
Chris Mason 已提交
1586

1587 1588 1589 1590
	err = btrfs_interface_init();
	if (err)
		goto free_delayed_inode;

1591 1592 1593
	err = register_filesystem(&btrfs_fs_type);
	if (err)
		goto unregister_ioctl;
1594

1595 1596
	btrfs_init_lockdep();

1597
	printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
1598 1599
	return 0;

1600 1601
unregister_ioctl:
	btrfs_interface_exit();
1602 1603
free_delayed_inode:
	btrfs_delayed_inode_exit();
1604 1605
free_extent_map:
	extent_map_exit();
1606 1607
free_extent_io:
	extent_io_exit();
1608 1609
free_cachep:
	btrfs_destroy_cachep();
1610 1611
free_compress:
	btrfs_exit_compress();
1612 1613
	btrfs_exit_sysfs();
	return err;
1614 1615 1616 1617
}

static void __exit exit_btrfs_fs(void)
{
C
Chris Mason 已提交
1618
	btrfs_destroy_cachep();
1619
	btrfs_delayed_inode_exit();
1620
	extent_map_exit();
1621
	extent_io_exit();
1622
	btrfs_interface_exit();
1623
	unregister_filesystem(&btrfs_fs_type);
1624
	btrfs_exit_sysfs();
1625
	btrfs_cleanup_fs_uuids();
1626
	btrfs_exit_compress();
1627 1628 1629 1630 1631 1632
}

module_init(init_btrfs_fs)
module_exit(exit_btrfs_fs)

MODULE_LICENSE("GPL");