/*
   * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.

   * Copyright (C) 2004-2008 Red Hat, Inc.  All rights reserved.

   *
   * This copyrighted material is made available to anyone wishing to use,
   * modify, copy, or redistribute it subject to the terms and conditions

   * of the GNU General Public License version 2.

   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  #include <linux/sched.h>
  #include <linux/slab.h>
  #include <linux/spinlock.h>
  #include <linux/completion.h>
  #include <linux/buffer_head.h>

  #include <linux/blkdev.h>
  #include <linux/kthread.h>

  #include <linux/export.h>

  #include <linux/namei.h>
  #include <linux/mount.h>

  #include <linux/gfs2_ondisk.h>

  #include <linux/quotaops.h>

  #include <linux/lockdep.h>

  #include <linux/module.h>

  #include <linux/backing-dev.h>

  
  #include "gfs2.h"

  #include "incore.h"

  #include "bmap.h"

  #include "glock.h"
  #include "glops.h"
  #include "inode.h"

  #include "recovery.h"
  #include "rgrp.h"
  #include "super.h"

  #include "sys.h"

  #include "util.h"

  #include "log.h"

  #include "quota.h"

  #include "dir.h"

  #include "meta_io.h"

  #include "trace_gfs2.h"

  
  #define DO 0
  #define UNDO 1

  /**
   * gfs2_tune_init - Fill a gfs2_tune structure with default values
   * @gt: tune
   *
   */
  
  static void gfs2_tune_init(struct gfs2_tune *gt)
  {
  	spin_lock_init(&gt->gt_spin);

  	gt->gt_quota_warn_period = 10;
  	gt->gt_quota_scale_num = 1;
  	gt->gt_quota_scale_den = 1;

  	gt->gt_new_files_jdata = 0;

  	gt->gt_max_readahead = BIT(18);

  	gt->gt_complain_secs = 10;

  }

  static struct gfs2_sbd *init_sbd(struct super_block *sb)
  {
  	struct gfs2_sbd *sdp;

  	struct address_space *mapping;

  	sdp = kzalloc(sizeof(struct gfs2_sbd), GFP_KERNEL);

  	if (!sdp)
  		return NULL;

  	sdp->sd_vfs = sb;

  	sdp->sd_lkstats = alloc_percpu(struct gfs2_pcpu_lkstats);
  	if (!sdp->sd_lkstats) {
  		kfree(sdp);
  		return NULL;
  	}

  	sb->s_fs_info = sdp;

  	set_bit(SDF_NOJOURNALID, &sdp->sd_flags);

  	gfs2_tune_init(&sdp->sd_tune);

  	init_waitqueue_head(&sdp->sd_glock_wait);
  	atomic_set(&sdp->sd_glock_disposal, 0);

  	init_completion(&sdp->sd_locking_init);

  	init_completion(&sdp->sd_wdack);

  	spin_lock_init(&sdp->sd_statfs_spin);

  
  	spin_lock_init(&sdp->sd_rindex_spin);

  	sdp->sd_rindex_tree.rb_node = NULL;

  
  	INIT_LIST_HEAD(&sdp->sd_jindex_list);
  	spin_lock_init(&sdp->sd_jindex_spin);

  	mutex_init(&sdp->sd_jindex_mutex);

  	init_completion(&sdp->sd_journal_ready);

  	INIT_LIST_HEAD(&sdp->sd_quota_list);

  	mutex_init(&sdp->sd_quota_mutex);

  	mutex_init(&sdp->sd_quota_sync_mutex);

  	init_waitqueue_head(&sdp->sd_quota_wait);

  	INIT_LIST_HEAD(&sdp->sd_trunc_list);
  	spin_lock_init(&sdp->sd_trunc_lock);

  	spin_lock_init(&sdp->sd_bitmap_lock);

  	mapping = &sdp->sd_aspace;

  	address_space_init_once(mapping);

  	mapping->a_ops = &gfs2_rgrp_aops;

  	mapping->host = sb->s_bdev->bd_inode;
  	mapping->flags = 0;
  	mapping_set_gfp_mask(mapping, GFP_NOFS);
  	mapping->private_data = NULL;

  	mapping->writeback_index = 0;

  	spin_lock_init(&sdp->sd_log_lock);

  	atomic_set(&sdp->sd_log_pinned, 0);

  	INIT_LIST_HEAD(&sdp->sd_log_le_revoke);

  	INIT_LIST_HEAD(&sdp->sd_log_le_ordered);

  	spin_lock_init(&sdp->sd_ordered_lock);

  	init_waitqueue_head(&sdp->sd_log_waitq);
  	init_waitqueue_head(&sdp->sd_logd_waitq);

  	spin_lock_init(&sdp->sd_ail_lock);

  	INIT_LIST_HEAD(&sdp->sd_ail1_list);
  	INIT_LIST_HEAD(&sdp->sd_ail2_list);

  	init_rwsem(&sdp->sd_log_flush_lock);

  	atomic_set(&sdp->sd_log_in_flight, 0);

  	atomic_set(&sdp->sd_reserving_log, 0);
  	init_waitqueue_head(&sdp->sd_reserving_log_wait);

  	init_waitqueue_head(&sdp->sd_log_flush_wait);

  	atomic_set(&sdp->sd_freeze_state, SFS_UNFROZEN);
  	mutex_init(&sdp->sd_freeze_mutex);

  	return sdp;
  }

  /**
   * gfs2_check_sb - Check superblock
   * @sdp: the filesystem
   * @sb: The superblock
   * @silent: Don't print a message if the check fails
   *
   * Checks the version code of the FS is one that we understand how to
   * read and that the sizes of the various on-disk structures have not
   * changed.
   */

  static int gfs2_check_sb(struct gfs2_sbd *sdp, int silent)

  {

  	struct gfs2_sb_host *sb = &sdp->sd_sb;

  	if (sb->sb_magic != GFS2_MAGIC ||
  	    sb->sb_type != GFS2_METATYPE_SB) {
  		if (!silent)

  			pr_warn("not a GFS2 filesystem
  ");

  		return -EINVAL;
  	}
  
  	/*  If format numbers match exactly, we're done.  */
  
  	if (sb->sb_fs_format == GFS2_FORMAT_FS &&
  	    sb->sb_multihost_format == GFS2_FORMAT_MULTI)
  		return 0;

  	fs_warn(sdp, "Unknown on-disk format, unable to mount
  ");

  	return -EINVAL;

  }

  static void end_bio_io_page(struct bio *bio)

  {
  	struct page *page = bio->bi_private;

  	if (!bio->bi_status)

  		SetPageUptodate(page);
  	else

  		pr_warn("error %d reading superblock
  ", bio->bi_status);

  	unlock_page(page);
  }

  static void gfs2_sb_in(struct gfs2_sbd *sdp, const void *buf)

  {

  	struct gfs2_sb_host *sb = &sdp->sd_sb;
  	struct super_block *s = sdp->sd_vfs;

  	const struct gfs2_sb *str = buf;
  
  	sb->sb_magic = be32_to_cpu(str->sb_header.mh_magic);
  	sb->sb_type = be32_to_cpu(str->sb_header.mh_type);
  	sb->sb_format = be32_to_cpu(str->sb_header.mh_format);
  	sb->sb_fs_format = be32_to_cpu(str->sb_fs_format);
  	sb->sb_multihost_format = be32_to_cpu(str->sb_multihost_format);
  	sb->sb_bsize = be32_to_cpu(str->sb_bsize);
  	sb->sb_bsize_shift = be32_to_cpu(str->sb_bsize_shift);
  	sb->sb_master_dir.no_addr = be64_to_cpu(str->sb_master_dir.no_addr);
  	sb->sb_master_dir.no_formal_ino = be64_to_cpu(str->sb_master_dir.no_formal_ino);
  	sb->sb_root_dir.no_addr = be64_to_cpu(str->sb_root_dir.no_addr);
  	sb->sb_root_dir.no_formal_ino = be64_to_cpu(str->sb_root_dir.no_formal_ino);
  
  	memcpy(sb->sb_lockproto, str->sb_lockproto, GFS2_LOCKNAME_LEN);
  	memcpy(sb->sb_locktable, str->sb_locktable, GFS2_LOCKNAME_LEN);

  	memcpy(&s->s_uuid, str->sb_uuid, 16);

  }
  
  /**
   * gfs2_read_super - Read the gfs2 super block from disk
   * @sdp: The GFS2 super block
   * @sector: The location of the super block
   * @error: The error code to return
   *
   * This uses the bio functions to read the super block from disk
   * because we want to be 100% sure that we never read cached data.
   * A super block is read twice only during each GFS2 mount and is
   * never written to by the filesystem. The first time its read no
   * locks are held, and the only details which are looked at are those
   * relating to the locking protocol. Once locking is up and working,
   * the sb is read again under the lock to establish the location of
   * the master directory (contains pointers to journals etc) and the
   * root directory.
   *
   * Returns: 0 on success or error
   */

  static int gfs2_read_super(struct gfs2_sbd *sdp, sector_t sector, int silent)

  {
  	struct super_block *sb = sdp->sd_vfs;
  	struct gfs2_sb *p;
  	struct page *page;
  	struct bio *bio;
  
  	page = alloc_page(GFP_NOFS);
  	if (unlikely(!page))

  		return -ENOMEM;

  
  	ClearPageUptodate(page);
  	ClearPageDirty(page);
  	lock_page(page);
  
  	bio = bio_alloc(GFP_NOFS, 1);

  	bio->bi_iter.bi_sector = sector * (sb->s_blocksize >> 9);

  	bio_set_dev(bio, sb->s_bdev);

  	bio_add_page(bio, page, PAGE_SIZE, 0);
  
  	bio->bi_end_io = end_bio_io_page;
  	bio->bi_private = page;

  	bio_set_op_attrs(bio, REQ_OP_READ, REQ_META);

  	submit_bio(bio);

  	wait_on_page_locked(page);
  	bio_put(bio);
  	if (!PageUptodate(page)) {
  		__free_page(page);
  		return -EIO;
  	}
  	p = kmap(page);

  	gfs2_sb_in(sdp, p);

  	kunmap(page);
  	__free_page(page);

  	return gfs2_check_sb(sdp, silent);

  }

  /**
   * gfs2_read_sb - Read super block
   * @sdp: The GFS2 superblock

   * @silent: Don't print message if mount fails
   *
   */

  static int gfs2_read_sb(struct gfs2_sbd *sdp, int silent)

  {
  	u32 hash_blocks, ind_blocks, leaf_blocks;
  	u32 tmp_blocks;
  	unsigned int x;
  	int error;

  	error = gfs2_read_super(sdp, GFS2_SB_ADDR >> sdp->sd_fsb2bb_shift, silent);

  	if (error) {
  		if (!silent)
  			fs_err(sdp, "can't read superblock
  ");
  		return error;
  	}

  	sdp->sd_fsb2bb_shift = sdp->sd_sb.sb_bsize_shift -
  			       GFS2_BASIC_BLOCK_SHIFT;

  	sdp->sd_fsb2bb = BIT(sdp->sd_fsb2bb_shift);

  	sdp->sd_diptrs = (sdp->sd_sb.sb_bsize -
  			  sizeof(struct gfs2_dinode)) / sizeof(u64);
  	sdp->sd_inptrs = (sdp->sd_sb.sb_bsize -
  			  sizeof(struct gfs2_meta_header)) / sizeof(u64);
  	sdp->sd_jbsize = sdp->sd_sb.sb_bsize - sizeof(struct gfs2_meta_header);
  	sdp->sd_hash_bsize = sdp->sd_sb.sb_bsize / 2;
  	sdp->sd_hash_bsize_shift = sdp->sd_sb.sb_bsize_shift - 1;
  	sdp->sd_hash_ptrs = sdp->sd_hash_bsize / sizeof(u64);
  	sdp->sd_qc_per_block = (sdp->sd_sb.sb_bsize -
  				sizeof(struct gfs2_meta_header)) /
  			        sizeof(struct gfs2_quota_change);

  	sdp->sd_blocks_per_bitmap = (sdp->sd_sb.sb_bsize -
  				     sizeof(struct gfs2_meta_header))
  		* GFS2_NBBY; /* not the rgrp bitmap, subsequent bitmaps only */

  
  	/* Compute maximum reservation required to add a entry to a directory */

  	hash_blocks = DIV_ROUND_UP(sizeof(u64) * BIT(GFS2_DIR_MAX_DEPTH),

  			     sdp->sd_jbsize);
  
  	ind_blocks = 0;
  	for (tmp_blocks = hash_blocks; tmp_blocks > sdp->sd_diptrs;) {
  		tmp_blocks = DIV_ROUND_UP(tmp_blocks, sdp->sd_inptrs);
  		ind_blocks += tmp_blocks;
  	}
  
  	leaf_blocks = 2 + GFS2_DIR_MAX_DEPTH;
  
  	sdp->sd_max_dirres = hash_blocks + ind_blocks + leaf_blocks;
  
  	sdp->sd_heightsize[0] = sdp->sd_sb.sb_bsize -
  				sizeof(struct gfs2_dinode);
  	sdp->sd_heightsize[1] = sdp->sd_sb.sb_bsize * sdp->sd_diptrs;
  	for (x = 2;; x++) {
  		u64 space, d;
  		u32 m;
  
  		space = sdp->sd_heightsize[x - 1] * sdp->sd_inptrs;
  		d = space;
  		m = do_div(d, sdp->sd_inptrs);
  
  		if (d != sdp->sd_heightsize[x - 1] || m)
  			break;
  		sdp->sd_heightsize[x] = space;
  	}
  	sdp->sd_max_height = x;
  	sdp->sd_heightsize[x] = ~0;
  	gfs2_assert(sdp, sdp->sd_max_height <= GFS2_MAX_META_HEIGHT);
  
  	sdp->sd_jheightsize[0] = sdp->sd_sb.sb_bsize -
  				 sizeof(struct gfs2_dinode);
  	sdp->sd_jheightsize[1] = sdp->sd_jbsize * sdp->sd_diptrs;
  	for (x = 2;; x++) {
  		u64 space, d;
  		u32 m;
  
  		space = sdp->sd_jheightsize[x - 1] * sdp->sd_inptrs;
  		d = space;
  		m = do_div(d, sdp->sd_inptrs);
  
  		if (d != sdp->sd_jheightsize[x - 1] || m)
  			break;
  		sdp->sd_jheightsize[x] = space;
  	}
  	sdp->sd_max_jheight = x;
  	sdp->sd_jheightsize[x] = ~0;
  	gfs2_assert(sdp, sdp->sd_max_jheight <= GFS2_MAX_META_HEIGHT);

  	sdp->sd_max_dents_per_leaf = (sdp->sd_sb.sb_bsize -
  				      sizeof(struct gfs2_leaf)) /
  				     GFS2_MIN_DIRENT_SIZE;

  	return 0;
  }

  static int init_names(struct gfs2_sbd *sdp, int silent)
  {

  	char *proto, *table;
  	int error = 0;
  
  	proto = sdp->sd_args.ar_lockproto;
  	table = sdp->sd_args.ar_locktable;
  
  	/*  Try to autodetect  */
  
  	if (!proto[0] || !table[0]) {

  		error = gfs2_read_super(sdp, GFS2_SB_ADDR >> sdp->sd_fsb2bb_shift, silent);

  		if (error)
  			return error;

  		if (!proto[0])

  			proto = sdp->sd_sb.sb_lockproto;

  		if (!table[0])

  			table = sdp->sd_sb.sb_locktable;

  	}
  
  	if (!table[0])
  		table = sdp->sd_vfs->s_id;

  	strlcpy(sdp->sd_proto_name, proto, GFS2_FSNAME_LEN);
  	strlcpy(sdp->sd_table_name, table, GFS2_FSNAME_LEN);

  	table = sdp->sd_table_name;
  	while ((table = strchr(table, '/')))

  		*table = '_';

  	return error;
  }
  
  static int init_locking(struct gfs2_sbd *sdp, struct gfs2_holder *mount_gh,
  			int undo)
  {

  	int error = 0;
  
  	if (undo)
  		goto fail_trans;

  	error = gfs2_glock_nq_num(sdp,
  				  GFS2_MOUNT_LOCK, &gfs2_nondisk_glops,
  				  LM_ST_EXCLUSIVE, LM_FLAG_NOEXP | GL_NOCACHE,
  				  mount_gh);
  	if (error) {
  		fs_err(sdp, "can't acquire mount glock: %d
  ", error);
  		goto fail;
  	}
  
  	error = gfs2_glock_nq_num(sdp,
  				  GFS2_LIVE_LOCK, &gfs2_nondisk_glops,
  				  LM_ST_SHARED,

  				  LM_FLAG_NOEXP | GL_EXACT,

  				  &sdp->sd_live_gh);
  	if (error) {
  		fs_err(sdp, "can't acquire live glock: %d
  ", error);
  		goto fail_mount;
  	}
  
  	error = gfs2_glock_get(sdp, GFS2_RENAME_LOCK, &gfs2_nondisk_glops,
  			       CREATE, &sdp->sd_rename_gl);
  	if (error) {
  		fs_err(sdp, "can't create rename glock: %d
  ", error);
  		goto fail_live;
  	}

  	error = gfs2_glock_get(sdp, GFS2_FREEZE_LOCK, &gfs2_freeze_glops,
  			       CREATE, &sdp->sd_freeze_gl);

  	if (error) {
  		fs_err(sdp, "can't create transaction glock: %d
  ", error);
  		goto fail_rename;
  	}

  
  	return 0;

  fail_trans:

  	gfs2_glock_put(sdp->sd_freeze_gl);

  fail_rename:

  	gfs2_glock_put(sdp->sd_rename_gl);

  fail_live:

  	gfs2_glock_dq_uninit(&sdp->sd_live_gh);

  fail_mount:

  	gfs2_glock_dq_uninit(mount_gh);

  fail:

  	return error;
  }

  static int gfs2_lookup_root(struct super_block *sb, struct dentry **dptr,
  			    u64 no_addr, const char *name)

  {

  	struct gfs2_sbd *sdp = sb->s_fs_info;
  	struct dentry *dentry;
  	struct inode *inode;

  	inode = gfs2_inode_lookup(sb, DT_DIR, no_addr, 0,
  				  GFS2_BLKST_FREE /* ignore */);

  	if (IS_ERR(inode)) {
  		fs_err(sdp, "can't read in %s inode: %ld
  ", name, PTR_ERR(inode));
  		return PTR_ERR(inode);
  	}

  	dentry = d_make_root(inode);

  	if (!dentry) {
  		fs_err(sdp, "can't alloc %s dentry
  ", name);

  		return -ENOMEM;
  	}

  	*dptr = dentry;
  	return 0;

  }

  static int init_sb(struct gfs2_sbd *sdp, int silent)

  {
  	struct super_block *sb = sdp->sd_vfs;
  	struct gfs2_holder sb_gh;

  	u64 no_addr;

  	int ret;

  	ret = gfs2_glock_nq_num(sdp, GFS2_SB_LOCK, &gfs2_meta_glops,
  				LM_ST_SHARED, 0, &sb_gh);
  	if (ret) {
  		fs_err(sdp, "can't acquire superblock glock: %d
  ", ret);
  		return ret;

  	}

  	ret = gfs2_read_sb(sdp, silent);

  	if (ret) {
  		fs_err(sdp, "can't read superblock: %d
  ", ret);

  		goto out;
  	}
  
  	/* Set up the buffer cache and SB for real */

  	if (sdp->sd_sb.sb_bsize < bdev_logical_block_size(sb->s_bdev)) {

  		ret = -EINVAL;

  		fs_err(sdp, "FS block size (%u) is too small for device "
  		       "block size (%u)
  ",

  		       sdp->sd_sb.sb_bsize, bdev_logical_block_size(sb->s_bdev));

  		goto out;
  	}
  	if (sdp->sd_sb.sb_bsize > PAGE_SIZE) {

  		ret = -EINVAL;

  		fs_err(sdp, "FS block size (%u) is too big for machine "
  		       "page size (%u)
  ",
  		       sdp->sd_sb.sb_bsize, (unsigned int)PAGE_SIZE);
  		goto out;
  	}

  	sb_set_blocksize(sb, sdp->sd_sb.sb_bsize);

  	/* Get the root inode */

  	no_addr = sdp->sd_sb.sb_root_dir.no_addr;

  	ret = gfs2_lookup_root(sb, &sdp->sd_root_dir, no_addr, "root");
  	if (ret)

  		goto out;

  	/* Get the master inode */
  	no_addr = sdp->sd_sb.sb_master_dir.no_addr;
  	ret = gfs2_lookup_root(sb, &sdp->sd_master_dir, no_addr, "master");
  	if (ret) {
  		dput(sdp->sd_root_dir);
  		goto out;
  	}
  	sb->s_root = dget(sdp->sd_args.ar_meta ? sdp->sd_master_dir : sdp->sd_root_dir);

  out:

  	gfs2_glock_dq_uninit(&sb_gh);

  	return ret;

  }

  static void gfs2_others_may_mount(struct gfs2_sbd *sdp)

  {

  	char *message = "FIRSTMOUNT=Done";
  	char *envp[] = { message, NULL };

  
  	fs_info(sdp, "first mount done, others may mount
  ");
  
  	if (sdp->sd_lockstruct.ls_ops->lm_first_done)
  		sdp->sd_lockstruct.ls_ops->lm_first_done(sdp);

  	kobject_uevent_env(&sdp->sd_kobj, KOBJ_CHANGE, envp);

  }

  /**
   * gfs2_jindex_hold - Grab a lock on the jindex
   * @sdp: The GFS2 superblock
   * @ji_gh: the holder for the jindex glock
   *
   * Returns: errno
   */
  
  static int gfs2_jindex_hold(struct gfs2_sbd *sdp, struct gfs2_holder *ji_gh)
  {
  	struct gfs2_inode *dip = GFS2_I(sdp->sd_jindex);
  	struct qstr name;
  	char buf[20];
  	struct gfs2_jdesc *jd;
  	int error;
  
  	name.name = buf;
  
  	mutex_lock(&sdp->sd_jindex_mutex);
  
  	for (;;) {
  		error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, ji_gh);
  		if (error)
  			break;
  
  		name.len = sprintf(buf, "journal%u", sdp->sd_journals);
  		name.hash = gfs2_disk_hash(name.name, name.len);
  
  		error = gfs2_dir_check(sdp->sd_jindex, &name, NULL);
  		if (error == -ENOENT) {
  			error = 0;
  			break;
  		}
  
  		gfs2_glock_dq_uninit(ji_gh);
  
  		if (error)
  			break;
  
  		error = -ENOMEM;
  		jd = kzalloc(sizeof(struct gfs2_jdesc), GFP_KERNEL);
  		if (!jd)
  			break;
  
  		INIT_LIST_HEAD(&jd->extent_list);

  		INIT_LIST_HEAD(&jd->jd_revoke_list);

  		INIT_WORK(&jd->jd_work, gfs2_recover_func);

  		jd->jd_inode = gfs2_lookupi(sdp->sd_jindex, &name, 1);
  		if (!jd->jd_inode || IS_ERR(jd->jd_inode)) {
  			if (!jd->jd_inode)
  				error = -ENOENT;
  			else
  				error = PTR_ERR(jd->jd_inode);
  			kfree(jd);
  			break;
  		}
  
  		spin_lock(&sdp->sd_jindex_spin);
  		jd->jd_jid = sdp->sd_journals++;
  		list_add_tail(&jd->jd_list, &sdp->sd_jindex_list);
  		spin_unlock(&sdp->sd_jindex_spin);
  	}
  
  	mutex_unlock(&sdp->sd_jindex_mutex);
  
  	return error;
  }

  /**
   * check_journal_clean - Make sure a journal is clean for a spectator mount
   * @sdp: The GFS2 superblock
   * @jd: The journal descriptor
   *
   * Returns: 0 if the journal is clean or locked, else an error
   */
  static int check_journal_clean(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd)
  {
  	int error;
  	struct gfs2_holder j_gh;
  	struct gfs2_log_header_host head;
  	struct gfs2_inode *ip;
  
  	ip = GFS2_I(jd->jd_inode);
  	error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_NOEXP |
  				   GL_EXACT | GL_NOCACHE, &j_gh);
  	if (error) {
  		fs_err(sdp, "Error locking journal for spectator mount.
  ");
  		return -EPERM;
  	}
  	error = gfs2_jdesc_check(jd);
  	if (error) {
  		fs_err(sdp, "Error checking journal for spectator mount.
  ");
  		goto out_unlock;
  	}
  	error = gfs2_find_jhead(jd, &head);
  	if (error) {
  		fs_err(sdp, "Error parsing journal for spectator mount.
  ");
  		goto out_unlock;
  	}
  	if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
  		error = -EPERM;
  		fs_err(sdp, "jid=%u: Journal is dirty, so the first mounter "
  		       "must not be a spectator.
  ", jd->jd_jid);
  	}
  
  out_unlock:
  	gfs2_glock_dq_uninit(&j_gh);
  	return error;
  }

  static int init_journal(struct gfs2_sbd *sdp, int undo)
  {

  	struct inode *master = d_inode(sdp->sd_master_dir);

  	struct gfs2_holder ji_gh;

  	struct gfs2_inode *ip;

  	int jindex = 1;
  	int error = 0;
  
  	if (undo) {
  		jindex = 0;

  		goto fail_jinode_gh;

  	}

  	sdp->sd_jindex = gfs2_lookup_simple(master, "jindex");

  	if (IS_ERR(sdp->sd_jindex)) {

  		fs_err(sdp, "can't lookup journal index: %d
  ", error);

  		return PTR_ERR(sdp->sd_jindex);

  	}

  
  	/* Load in the journal index special file */
  
  	error = gfs2_jindex_hold(sdp, &ji_gh);
  	if (error) {
  		fs_err(sdp, "can't read journal index: %d
  ", error);
  		goto fail;
  	}

  	error = -EUSERS;

  	if (!gfs2_jindex_size(sdp)) {
  		fs_err(sdp, "no journals!
  ");

  		goto fail_jindex;

  	}

  	atomic_set(&sdp->sd_log_blks_needed, 0);

  	if (sdp->sd_args.ar_spectator) {
  		sdp->sd_jdesc = gfs2_jdesc_find(sdp, 0);

  		atomic_set(&sdp->sd_log_blks_free, sdp->sd_jdesc->jd_blocks);

  		atomic_set(&sdp->sd_log_thresh1, 2*sdp->sd_jdesc->jd_blocks/5);
  		atomic_set(&sdp->sd_log_thresh2, 4*sdp->sd_jdesc->jd_blocks/5);

  	} else {
  		if (sdp->sd_lockstruct.ls_jid >= gfs2_jindex_size(sdp)) {
  			fs_err(sdp, "can't mount journal #%u
  ",
  			       sdp->sd_lockstruct.ls_jid);
  			fs_err(sdp, "there are only %u journals (0 - %u)
  ",
  			       gfs2_jindex_size(sdp),
  			       gfs2_jindex_size(sdp) - 1);
  			goto fail_jindex;
  		}
  		sdp->sd_jdesc = gfs2_jdesc_find(sdp, sdp->sd_lockstruct.ls_jid);

  		error = gfs2_glock_nq_num(sdp, sdp->sd_lockstruct.ls_jid,

  					  &gfs2_journal_glops,
  					  LM_ST_EXCLUSIVE, LM_FLAG_NOEXP,
  					  &sdp->sd_journal_gh);
  		if (error) {
  			fs_err(sdp, "can't acquire journal glock: %d
  ", error);
  			goto fail_jindex;
  		}

  		ip = GFS2_I(sdp->sd_jdesc->jd_inode);
  		error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED,

  					   LM_FLAG_NOEXP | GL_EXACT | GL_NOCACHE,

  					   &sdp->sd_jinode_gh);
  		if (error) {
  			fs_err(sdp, "can't acquire journal inode glock: %d
  ",
  			       error);
  			goto fail_journal_gh;
  		}
  
  		error = gfs2_jdesc_check(sdp->sd_jdesc);
  		if (error) {
  			fs_err(sdp, "my journal (%u) is bad: %d
  ",
  			       sdp->sd_jdesc->jd_jid, error);
  			goto fail_jinode_gh;
  		}

  		atomic_set(&sdp->sd_log_blks_free, sdp->sd_jdesc->jd_blocks);

  		atomic_set(&sdp->sd_log_thresh1, 2*sdp->sd_jdesc->jd_blocks/5);
  		atomic_set(&sdp->sd_log_thresh2, 4*sdp->sd_jdesc->jd_blocks/5);

  
  		/* Map the extents for this journal's blocks */

  		gfs2_map_journal_extents(sdp, sdp->sd_jdesc);

  	}

  	trace_gfs2_log_blocks(sdp, atomic_read(&sdp->sd_log_blks_free));

  
  	if (sdp->sd_lockstruct.ls_first) {
  		unsigned int x;
  		for (x = 0; x < sdp->sd_journals; x++) {

  			struct gfs2_jdesc *jd = gfs2_jdesc_find(sdp, x);
  
  			if (sdp->sd_args.ar_spectator) {
  				error = check_journal_clean(sdp, jd);
  				if (error)
  					goto fail_jinode_gh;
  				continue;
  			}
  			error = gfs2_recover_journal(jd, true);

  			if (error) {
  				fs_err(sdp, "error recovering journal %u: %d
  ",
  				       x, error);
  				goto fail_jinode_gh;
  			}
  		}

  		gfs2_others_may_mount(sdp);

  	} else if (!sdp->sd_args.ar_spectator) {

  		error = gfs2_recover_journal(sdp->sd_jdesc, true);

  		if (error) {
  			fs_err(sdp, "error recovering my journal: %d
  ", error);
  			goto fail_jinode_gh;
  		}
  	}

  	sdp->sd_log_idle = 1;

  	set_bit(SDF_JOURNAL_CHECKED, &sdp->sd_flags);
  	gfs2_glock_dq_uninit(&ji_gh);
  	jindex = 0;

  	INIT_WORK(&sdp->sd_freeze_work, gfs2_freeze_func);

  	return 0;

  fail_jinode_gh:

  	if (!sdp->sd_args.ar_spectator)
  		gfs2_glock_dq_uninit(&sdp->sd_jinode_gh);

  fail_journal_gh:

  	if (!sdp->sd_args.ar_spectator)
  		gfs2_glock_dq_uninit(&sdp->sd_journal_gh);

  fail_jindex:

  	gfs2_jindex_free(sdp);
  	if (jindex)
  		gfs2_glock_dq_uninit(&ji_gh);

  fail:

  	iput(sdp->sd_jindex);

  	return error;
  }

  static struct lock_class_key gfs2_quota_imutex_key;

  
  static int init_inodes(struct gfs2_sbd *sdp, int undo)
  {

  	int error = 0;

  	struct inode *master = d_inode(sdp->sd_master_dir);

  
  	if (undo)

  		goto fail_qinode;

  	error = init_journal(sdp, undo);

  	complete_all(&sdp->sd_journal_ready);

  	if (error)

  		goto fail;

  	/* Read in the master statfs inode */

  	sdp->sd_statfs_inode = gfs2_lookup_simple(master, "statfs");

  	if (IS_ERR(sdp->sd_statfs_inode)) {
  		error = PTR_ERR(sdp->sd_statfs_inode);

  		fs_err(sdp, "can't read in statfs inode: %d
  ", error);

  		goto fail_journal;

  	}
  
  	/* Read in the resource index inode */

  	sdp->sd_rindex = gfs2_lookup_simple(master, "rindex");

  	if (IS_ERR(sdp->sd_rindex)) {
  		error = PTR_ERR(sdp->sd_rindex);

  		fs_err(sdp, "can't get resource index inode: %d
  ", error);
  		goto fail_statfs;
  	}

  	sdp->sd_rindex_uptodate = 0;

  
  	/* Read in the quota inode */

  	sdp->sd_quota_inode = gfs2_lookup_simple(master, "quota");

  	if (IS_ERR(sdp->sd_quota_inode)) {
  		error = PTR_ERR(sdp->sd_quota_inode);

  		fs_err(sdp, "can't get quota file inode: %d
  ", error);
  		goto fail_rindex;
  	}

  	/*
  	 * i_mutex on quota files is special. Since this inode is hidden system
  	 * file, we are safe to define locking ourselves.
  	 */

  	lockdep_set_class(&sdp->sd_quota_inode->i_rwsem,

  			  &gfs2_quota_imutex_key);

  
  	error = gfs2_rindex_update(sdp);
  	if (error)
  		goto fail_qinode;

  	return 0;

  fail_qinode:
  	iput(sdp->sd_quota_inode);

  fail_rindex:

  	gfs2_clear_rgrpd(sdp);

  	iput(sdp->sd_rindex);

  fail_statfs:
  	iput(sdp->sd_statfs_inode);

  fail_journal:
  	init_journal(sdp, UNDO);

  fail:

  	return error;
  }
  
  static int init_per_node(struct gfs2_sbd *sdp, int undo)
  {

  	struct inode *pn = NULL;

  	char buf[30];
  	int error = 0;

  	struct gfs2_inode *ip;

  	struct inode *master = d_inode(sdp->sd_master_dir);

  
  	if (sdp->sd_args.ar_spectator)
  		return 0;
  
  	if (undo)
  		goto fail_qc_gh;

  	pn = gfs2_lookup_simple(master, "per_node");

  	if (IS_ERR(pn)) {
  		error = PTR_ERR(pn);

  		fs_err(sdp, "can't find per_node directory: %d
  ", error);
  		return error;
  	}

  	sprintf(buf, "statfs_change%u", sdp->sd_jdesc->jd_jid);

  	sdp->sd_sc_inode = gfs2_lookup_simple(pn, buf);
  	if (IS_ERR(sdp->sd_sc_inode)) {
  		error = PTR_ERR(sdp->sd_sc_inode);

  		fs_err(sdp, "can't find local \"sc\" file: %d
  ", error);

  		goto fail;

  	}

  	sprintf(buf, "quota_change%u", sdp->sd_jdesc->jd_jid);

  	sdp->sd_qc_inode = gfs2_lookup_simple(pn, buf);
  	if (IS_ERR(sdp->sd_qc_inode)) {
  		error = PTR_ERR(sdp->sd_qc_inode);

  		fs_err(sdp, "can't find local \"qc\" file: %d
  ", error);
  		goto fail_ut_i;
  	}

  	iput(pn);

  	pn = NULL;

  	ip = GFS2_I(sdp->sd_sc_inode);

  	error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0,

  				   &sdp->sd_sc_gh);
  	if (error) {
  		fs_err(sdp, "can't lock local \"sc\" file: %d
  ", error);

  		goto fail_qc_i;

  	}

  	ip = GFS2_I(sdp->sd_qc_inode);

  	error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0,

  				   &sdp->sd_qc_gh);
  	if (error) {
  		fs_err(sdp, "can't lock local \"qc\" file: %d
  ", error);
  		goto fail_ut_gh;
  	}
  
  	return 0;

  fail_qc_gh:

  	gfs2_glock_dq_uninit(&sdp->sd_qc_gh);

  fail_ut_gh:

  	gfs2_glock_dq_uninit(&sdp->sd_sc_gh);

  fail_qc_i:

  	iput(sdp->sd_qc_inode);

  fail_ut_i:

  	iput(sdp->sd_sc_inode);

  fail:

  	iput(pn);

  	return error;
  }

  static const match_table_t nolock_tokens = {
  	{ Opt_jid, "jid=%d
  ", },
  	{ Opt_err, NULL },
  };
  
  static const struct lm_lockops nolock_ops = {
  	.lm_proto_name = "lock_nolock",

  	.lm_put_lock = gfs2_glock_free,

  	.lm_tokens = &nolock_tokens,
  };

  /**
   * gfs2_lm_mount - mount a locking protocol
   * @sdp: the filesystem

   * @args: mount arguments

   * @silent: if 1, don't complain if the FS isn't a GFS2 fs
   *
   * Returns: errno
   */
  
  static int gfs2_lm_mount(struct gfs2_sbd *sdp, int silent)
  {

  	const struct lm_lockops *lm;
  	struct lm_lockstruct *ls = &sdp->sd_lockstruct;
  	struct gfs2_args *args = &sdp->sd_args;
  	const char *proto = sdp->sd_proto_name;
  	const char *table = sdp->sd_table_name;

  	char *o, *options;
  	int ret;

  	if (!strcmp("lock_nolock", proto)) {
  		lm = &nolock_ops;
  		sdp->sd_args.ar_localflocks = 1;

  #ifdef CONFIG_GFS2_FS_LOCKING_DLM
  	} else if (!strcmp("lock_dlm", proto)) {
  		lm = &gfs2_dlm_ops;
  #endif
  	} else {

  		pr_info("can't find protocol %s
  ", proto);

  		return -ENOENT;
  	}

  
  	fs_info(sdp, "Trying to join cluster \"%s\", \"%s\"
  ", proto, table);

  	ls->ls_ops = lm;
  	ls->ls_first = 1;

  	for (options = args->ar_hostdata; (o = strsep(&options, ":")); ) {
  		substring_t tmp[MAX_OPT_ARGS];
  		int token, option;
  
  		if (!o || !*o)
  			continue;
  
  		token = match_token(o, *lm->lm_tokens, tmp);
  		switch (token) {
  		case Opt_jid:
  			ret = match_int(&tmp[0], &option);
  			if (ret || option < 0) 
  				goto hostdata_error;

  			if (test_and_clear_bit(SDF_NOJOURNALID, &sdp->sd_flags))
  				ls->ls_jid = option;

  			break;
  		case Opt_id:

  		case Opt_nodir:

  			/* Obsolete, but left for backward compat purposes */

  			break;
  		case Opt_first:
  			ret = match_int(&tmp[0], &option);
  			if (ret || (option != 0 && option != 1))
  				goto hostdata_error;
  			ls->ls_first = option;
  			break;

  		case Opt_err:
  		default:
  hostdata_error:
  			fs_info(sdp, "unknown hostdata (%s)
  ", o);
  			return -EINVAL;
  		}

  	}

  	if (lm->lm_mount == NULL) {
  		fs_info(sdp, "Now mounting FS...
  ");

  		complete_all(&sdp->sd_locking_init);

  		return 0;

  	}

  	ret = lm->lm_mount(sdp, table);

  	if (ret == 0)
  		fs_info(sdp, "Joined cluster. Now mounting FS...
  ");

  	complete_all(&sdp->sd_locking_init);

  	return ret;

  }
  
  void gfs2_lm_unmount(struct gfs2_sbd *sdp)
  {

  	const struct lm_lockops *lm = sdp->sd_lockstruct.ls_ops;
  	if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)) &&
  	    lm->lm_unmount)
  		lm->lm_unmount(sdp);

  }

  static int wait_on_journal(struct gfs2_sbd *sdp)
  {

  	if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL)
  		return 0;

  	return wait_on_bit(&sdp->sd_flags, SDF_NOJOURNALID, TASK_INTERRUPTIBLE)
  		? -EINTR : 0;

  }

  void gfs2_online_uevent(struct gfs2_sbd *sdp)
  {
  	struct super_block *sb = sdp->sd_vfs;
  	char ro[20];
  	char spectator[20];
  	char *envp[] = { ro, spectator, NULL };

  	sprintf(ro, "RDONLY=%d", sb_rdonly(sb));

  	sprintf(spectator, "SPECTATOR=%d", sdp->sd_args.ar_spectator ? 1 : 0);
  	kobject_uevent_env(&sdp->sd_kobj, KOBJ_ONLINE, envp);
  }

  /**
   * fill_super - Read in superblock
   * @sb: The VFS superblock
   * @data: Mount options
   * @silent: Don't complain if it's not a GFS2 filesystem
   *
   * Returns: errno
   */

  static int fill_super(struct super_block *sb, struct gfs2_args *args, int silent)

  {
  	struct gfs2_sbd *sdp;
  	struct gfs2_holder mount_gh;
  	int error;
  
  	sdp = init_sbd(sb);
  	if (!sdp) {

  		pr_warn("can't alloc struct gfs2_sbd
  ");

  		return -ENOMEM;
  	}

  	sdp->sd_args = *args;

  	if (sdp->sd_args.ar_spectator) {

                  sb->s_flags |= MS_RDONLY;

  		set_bit(SDF_RORECOVERY, &sdp->sd_flags);

  	}

  	if (sdp->sd_args.ar_posix_acl)
  		sb->s_flags |= MS_POSIXACL;

  	if (sdp->sd_args.ar_nobarrier)
  		set_bit(SDF_NOBARRIERS, &sdp->sd_flags);

  	sb->s_flags |= MS_NOSEC;

  	sb->s_magic = GFS2_MAGIC;
  	sb->s_op = &gfs2_super_ops;

  	sb->s_d_op = &gfs2_dops;

  	sb->s_export_op = &gfs2_export_ops;

  	sb->s_xattr = gfs2_xattr_handlers;

  	sb->s_qcop = &gfs2_quotactl_ops;

  	sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP;

  	sb_dqopt(sb)->flags |= DQUOT_QUOTA_SYS_FILE;

  	sb->s_time_gran = 1;
  	sb->s_maxbytes = MAX_LFS_FILESIZE;

  
  	/* Set up the buffer cache and fill in some fake block size values
  	   to allow us to read-in the on-disk superblock. */
  	sdp->sd_sb.sb_bsize = sb_min_blocksize(sb, GFS2_BASIC_BLOCK);
  	sdp->sd_sb.sb_bsize_shift = sb->s_blocksize_bits;
  	sdp->sd_fsb2bb_shift = sdp->sd_sb.sb_bsize_shift -
                                 GFS2_BASIC_BLOCK_SHIFT;

  	sdp->sd_fsb2bb = BIT(sdp->sd_fsb2bb_shift);

  	sdp->sd_tune.gt_logd_secs = sdp->sd_args.ar_commit;

  	sdp->sd_tune.gt_quota_quantum = sdp->sd_args.ar_quota_quantum;
  	if (sdp->sd_args.ar_statfs_quantum) {
  		sdp->sd_tune.gt_statfs_slow = 0;
  		sdp->sd_tune.gt_statfs_quantum = sdp->sd_args.ar_statfs_quantum;

  	} else {

  		sdp->sd_tune.gt_statfs_slow = 1;
  		sdp->sd_tune.gt_statfs_quantum = 30;
  	}

  	error = init_names(sdp, silent);

  	if (error) {
  		/* In this case, we haven't initialized sysfs, so we have to
  		   manually free the sdp. */
  		free_percpu(sdp->sd_lkstats);
  		kfree(sdp);
  		sb->s_fs_info = NULL;
  		return error;
  	}

  	snprintf(sdp->sd_fsname, sizeof(sdp->sd_fsname), "%s", sdp->sd_table_name);

  	error = gfs2_sys_fs_add(sdp);

  	/*
  	 * If we hit an error here, gfs2_sys_fs_add will have called function
  	 * kobject_put which causes the sysfs usage count to go to zero, which
  	 * causes sysfs to call function gfs2_sbd_release, which frees sdp.
  	 * Subsequent error paths here will call gfs2_sys_fs_del, which also
  	 * kobject_put to free sdp.
  	 */

  	if (error)

  		return error;
  
  	gfs2_create_debugfs_file(sdp);

  
  	error = gfs2_lm_mount(sdp, silent);
  	if (error)

  		goto fail_debug;

  
  	error = init_locking(sdp, &mount_gh, DO);
  	if (error)
  		goto fail_lm;

  	error = init_sb(sdp, silent);

  	if (error)
  		goto fail_locking;

  	error = wait_on_journal(sdp);
  	if (error)
  		goto fail_sb;

  	/*
  	 * If user space has failed to join the cluster or some similar
  	 * failure has occurred, then the journal id will contain a
  	 * negative (error) number. This will then be returned to the
  	 * caller (of the mount syscall). We do this even for spectator
  	 * mounts (which just write a jid of 0 to indicate "ok" even though
  	 * the jid is unused in the spectator case)
  	 */
  	if (sdp->sd_lockstruct.ls_jid < 0) {
  		error = sdp->sd_lockstruct.ls_jid;
  		sdp->sd_lockstruct.ls_jid = 0;
  		goto fail_sb;
  	}

  	if (sdp->sd_args.ar_spectator)

  		snprintf(sdp->sd_fsname, sizeof(sdp->sd_fsname), "%s.s",

  			 sdp->sd_table_name);
  	else

  		snprintf(sdp->sd_fsname, sizeof(sdp->sd_fsname), "%s.%u",

  			 sdp->sd_table_name, sdp->sd_lockstruct.ls_jid);

  	error = init_inodes(sdp, DO);
  	if (error)

  		goto fail_sb;

  
  	error = init_per_node(sdp, DO);
  	if (error)
  		goto fail_inodes;
  
  	error = gfs2_statfs_init(sdp);
  	if (error) {
  		fs_err(sdp, "can't initialize statfs subsystem: %d
  ", error);
  		goto fail_per_node;
  	}

  	if (!sb_rdonly(sb)) {

  		error = gfs2_make_fs_rw(sdp);
  		if (error) {
  			fs_err(sdp, "can't make FS RW: %d
  ", error);

  			goto fail_per_node;

  		}
  	}
  
  	gfs2_glock_dq_uninit(&mount_gh);

  	gfs2_online_uevent(sdp);

  	return 0;

  fail_per_node:

  	init_per_node(sdp, UNDO);

  fail_inodes:

  	init_inodes(sdp, UNDO);

  fail_sb:

  	if (sdp->sd_root_dir)
  		dput(sdp->sd_root_dir);
  	if (sdp->sd_master_dir)
  		dput(sdp->sd_master_dir);

  	if (sb->s_root)
  		dput(sb->s_root);

  	sb->s_root = NULL;

  fail_locking:

  	init_locking(sdp, &mount_gh, UNDO);

  fail_lm:

  	complete_all(&sdp->sd_journal_ready);

  	gfs2_gl_hash_clear(sdp);

  	gfs2_lm_unmount(sdp);

  fail_debug:

  	gfs2_delete_debugfs_file(sdp);

  	free_percpu(sdp->sd_lkstats);

  	/* gfs2_sys_fs_del must be the last thing we do, since it causes
  	 * sysfs to call function gfs2_sbd_release, which frees sdp. */
  	gfs2_sys_fs_del(sdp);

  	sb->s_fs_info = NULL;

  	return error;
  }

  static int set_gfs2_super(struct super_block *s, void *data)

  {

  	s->s_bdev = data;
  	s->s_dev = s->s_bdev->bd_dev;

  	s->s_bdi = bdi_get(s->s_bdev->bd_bdi);

  	return 0;

  }

  static int test_gfs2_super(struct super_block *s, void *ptr)

  {
  	struct block_device *bdev = ptr;
  	return (bdev == s->s_bdev);
  }

  /**

   * gfs2_mount - Get the GFS2 superblock

   * @fs_type: The GFS2 filesystem type
   * @flags: Mount flags
   * @dev_name: The name of the device
   * @data: The mount arguments

   *
   * Q. Why not use get_sb_bdev() ?
   * A. We need to select one of two root directories to mount, independent
   *    of whether this is the initial, or subsequent, mount of this sb
   *
   * Returns: 0 or -ve on error
   */

  static struct dentry *gfs2_mount(struct file_system_type *fs_type, int flags,
  		       const char *dev_name, void *data)

  {
  	struct block_device *bdev;
  	struct super_block *s;

  	fmode_t mode = FMODE_READ | FMODE_EXCL;

  	int error;
  	struct gfs2_args args;
  	struct gfs2_sbd *sdp;
  
  	if (!(flags & MS_RDONLY))
  		mode |= FMODE_WRITE;

  	bdev = blkdev_get_by_path(dev_name, mode, fs_type);

  	if (IS_ERR(bdev))

  		return ERR_CAST(bdev);

  
  	/*
  	 * once the super is inserted into the list by sget, s_umount
  	 * will protect the lockfs code from trying to start a snapshot
  	 * while we are mounting
  	 */
  	mutex_lock(&bdev->bd_fsfreeze_mutex);
  	if (bdev->bd_fsfreeze_count > 0) {
  		mutex_unlock(&bdev->bd_fsfreeze_mutex);
  		error = -EBUSY;
  		goto error_bdev;
  	}

  	s = sget(fs_type, test_gfs2_super, set_gfs2_super, flags, bdev);

  	mutex_unlock(&bdev->bd_fsfreeze_mutex);
  	error = PTR_ERR(s);
  	if (IS_ERR(s))
  		goto error_bdev;

  	if (s->s_root) {
  		/*
  		 * s_umount nests inside bd_mutex during
  		 * __invalidate_device().  blkdev_put() acquires
  		 * bd_mutex and can't be called under s_umount.  Drop
  		 * s_umount temporarily.  This is safe as we're
  		 * holding an active reference.
  		 */
  		up_write(&s->s_umount);

  		blkdev_put(bdev, mode);

  		down_write(&s->s_umount);

  	} else {
  		/* s_mode must be set before deactivate_locked_super calls */
  		s->s_mode = mode;

  	}

  	memset(&args, 0, sizeof(args));
  	args.ar_quota = GFS2_QUOTA_DEFAULT;
  	args.ar_data = GFS2_DATA_DEFAULT;

  	args.ar_commit = 30;

  	args.ar_statfs_quantum = 30;
  	args.ar_quota_quantum = 60;

  	args.ar_errors = GFS2_ERRORS_DEFAULT;
  
  	error = gfs2_mount_args(&args, data);
  	if (error) {

  		pr_warn("can't parse mount arguments
  ");

  		goto error_super;

  	}
  
  	if (s->s_root) {
  		error = -EBUSY;
  		if ((flags ^ s->s_flags) & MS_RDONLY)
  			goto error_super;

  	} else {

  		snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);

  		sb_set_blocksize(s, block_size(bdev));
  		error = fill_super(s, &args, flags & MS_SILENT ? 1 : 0);

  		if (error)
  			goto error_super;

  		s->s_flags |= MS_ACTIVE;
  		bdev->bd_super = s;
  	}
  
  	sdp = s->s_fs_info;

  	if (args.ar_meta)

  		return dget(sdp->sd_master_dir);

  	else

  		return dget(sdp->sd_root_dir);

  
  error_super:
  	deactivate_locked_super(s);

  	return ERR_PTR(error);

  error_bdev:

  	blkdev_put(bdev, mode);

  	return ERR_PTR(error);

  }

  static int set_meta_super(struct super_block *s, void *ptr)
  {
  	return -EINVAL;
  }

  static struct dentry *gfs2_mount_meta(struct file_system_type *fs_type,
  			int flags, const char *dev_name, void *data)

  {

  	struct super_block *s;

  	struct gfs2_sbd *sdp;

  	struct path path;

  	int error;

  	if (!dev_name || !*dev_name)
  		return ERR_PTR(-EINVAL);

  	error = kern_path(dev_name, LOOKUP_FOLLOW, &path);

  	if (error) {

  		pr_warn("path_lookup on %s returned error %d
  ",
  			dev_name, error);

  		return ERR_PTR(error);

  	}

  	s = sget(&gfs2_fs_type, test_gfs2_super, set_meta_super, flags,

  		 path.dentry->d_sb->s_bdev);

  	path_put(&path);

  	if (IS_ERR(s)) {

  		pr_warn("gfs2 mount does not exist
  ");

  		return ERR_CAST(s);

  	}

  	if ((flags ^ s->s_flags) & MS_RDONLY) {
  		deactivate_locked_super(s);

  		return ERR_PTR(-EBUSY);

  	}

  	sdp = s->s_fs_info;

  	return dget(sdp->sd_master_dir);

  }

  static void gfs2_kill_sb(struct super_block *sb)
  {

  	struct gfs2_sbd *sdp = sb->s_fs_info;

  
  	if (sdp == NULL) {
  		kill_block_super(sb);
  		return;

  	}

  	gfs2_log_flush(sdp, NULL, SYNC_FLUSH);

  	dput(sdp->sd_root_dir);
  	dput(sdp->sd_master_dir);
  	sdp->sd_root_dir = NULL;
  	sdp->sd_master_dir = NULL;

  	shrink_dcache_sb(sb);

  	free_percpu(sdp->sd_lkstats);

  	kill_block_super(sb);

  }

  struct file_system_type gfs2_fs_type = {
  	.name = "gfs2",
  	.fs_flags = FS_REQUIRES_DEV,

  	.mount = gfs2_mount,

  	.kill_sb = gfs2_kill_sb,
  	.owner = THIS_MODULE,
  };

  MODULE_ALIAS_FS("gfs2");

  
  struct file_system_type gfs2meta_fs_type = {
  	.name = "gfs2meta",
  	.fs_flags = FS_REQUIRES_DEV,

  	.mount = gfs2_mount_meta,

  	.owner = THIS_MODULE,
  };

  MODULE_ALIAS_FS("gfs2meta");