This commit was manufactured by cvs2svn to create branch 'vserver'.
[linux-2.6.git] / fs / gfs2 / super.c
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
new file mode 100644 (file)
index 0000000..4fdda97
--- /dev/null
@@ -0,0 +1,985 @@
+/*
+ * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
+ * Copyright (C) 2004-2006 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.
+ */
+
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/buffer_head.h>
+#include <linux/crc32.h>
+#include <linux/gfs2_ondisk.h>
+#include <linux/bio.h>
+#include <linux/lm_interface.h>
+
+#include "gfs2.h"
+#include "incore.h"
+#include "bmap.h"
+#include "dir.h"
+#include "glock.h"
+#include "glops.h"
+#include "inode.h"
+#include "log.h"
+#include "meta_io.h"
+#include "quota.h"
+#include "recovery.h"
+#include "rgrp.h"
+#include "super.h"
+#include "trans.h"
+#include "util.h"
+
+static const u32 gfs2_old_fs_formats[] = {
+        0
+};
+
+static const u32 gfs2_old_multihost_formats[] = {
+        0
+};
+
+/**
+ * gfs2_tune_init - Fill a gfs2_tune structure with default values
+ * @gt: tune
+ *
+ */
+
+void gfs2_tune_init(struct gfs2_tune *gt)
+{
+       spin_lock_init(&gt->gt_spin);
+
+       gt->gt_ilimit = 100;
+       gt->gt_ilimit_tries = 3;
+       gt->gt_ilimit_min = 1;
+       gt->gt_demote_secs = 300;
+       gt->gt_incore_log_blocks = 1024;
+       gt->gt_log_flush_secs = 60;
+       gt->gt_jindex_refresh_secs = 60;
+       gt->gt_scand_secs = 15;
+       gt->gt_recoverd_secs = 60;
+       gt->gt_logd_secs = 1;
+       gt->gt_quotad_secs = 5;
+       gt->gt_quota_simul_sync = 64;
+       gt->gt_quota_warn_period = 10;
+       gt->gt_quota_scale_num = 1;
+       gt->gt_quota_scale_den = 1;
+       gt->gt_quota_cache_secs = 300;
+       gt->gt_quota_quantum = 60;
+       gt->gt_atime_quantum = 3600;
+       gt->gt_new_files_jdata = 0;
+       gt->gt_new_files_directio = 0;
+       gt->gt_max_readahead = 1 << 18;
+       gt->gt_lockdump_size = 131072;
+       gt->gt_stall_secs = 600;
+       gt->gt_complain_secs = 10;
+       gt->gt_reclaim_limit = 5000;
+       gt->gt_statfs_quantum = 30;
+       gt->gt_statfs_slow = 0;
+}
+
+/**
+ * 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.
+ */
+
+int gfs2_check_sb(struct gfs2_sbd *sdp, struct gfs2_sb_host *sb, int silent)
+{
+       unsigned int x;
+
+       if (sb->sb_header.mh_magic != GFS2_MAGIC ||
+           sb->sb_header.mh_type != GFS2_METATYPE_SB) {
+               if (!silent)
+                       printk(KERN_WARNING "GFS2: not a GFS2 filesystem\n");
+               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;
+
+       if (sb->sb_fs_format != GFS2_FORMAT_FS) {
+               for (x = 0; gfs2_old_fs_formats[x]; x++)
+                       if (gfs2_old_fs_formats[x] == sb->sb_fs_format)
+                               break;
+
+               if (!gfs2_old_fs_formats[x]) {
+                       printk(KERN_WARNING
+                              "GFS2: code version (%u, %u) is incompatible "
+                              "with ondisk format (%u, %u)\n",
+                              GFS2_FORMAT_FS, GFS2_FORMAT_MULTI,
+                              sb->sb_fs_format, sb->sb_multihost_format);
+                       printk(KERN_WARNING
+                              "GFS2: I don't know how to upgrade this FS\n");
+                       return -EINVAL;
+               }
+       }
+
+       if (sb->sb_multihost_format != GFS2_FORMAT_MULTI) {
+               for (x = 0; gfs2_old_multihost_formats[x]; x++)
+                       if (gfs2_old_multihost_formats[x] ==
+                           sb->sb_multihost_format)
+                               break;
+
+               if (!gfs2_old_multihost_formats[x]) {
+                       printk(KERN_WARNING
+                              "GFS2: code version (%u, %u) is incompatible "
+                              "with ondisk format (%u, %u)\n",
+                              GFS2_FORMAT_FS, GFS2_FORMAT_MULTI,
+                              sb->sb_fs_format, sb->sb_multihost_format);
+                       printk(KERN_WARNING
+                              "GFS2: I don't know how to upgrade this FS\n");
+                       return -EINVAL;
+               }
+       }
+
+       if (!sdp->sd_args.ar_upgrade) {
+               printk(KERN_WARNING
+                      "GFS2: code version (%u, %u) is incompatible "
+                      "with ondisk format (%u, %u)\n",
+                      GFS2_FORMAT_FS, GFS2_FORMAT_MULTI,
+                      sb->sb_fs_format, sb->sb_multihost_format);
+               printk(KERN_INFO
+                      "GFS2: Use the \"upgrade\" mount option to upgrade "
+                      "the FS\n");
+               printk(KERN_INFO "GFS2: See the manual for more details\n");
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+
+static int end_bio_io_page(struct bio *bio, unsigned int bytes_done, int error)
+{
+       struct page *page = bio->bi_private;
+       if (bio->bi_size)
+               return 1;
+
+       if (!error)
+               SetPageUptodate(page);
+       else
+               printk(KERN_WARNING "gfs2: error %d reading superblock\n", error);
+       unlock_page(page);
+       return 0;
+}
+
+/**
+ * gfs2_read_super - Read the gfs2 super block from disk
+ * @sb: The VFS super block
+ * @sector: The location of the super block
+ *
+ * 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: A page containing the sb or NULL
+ */
+
+struct page *gfs2_read_super(struct super_block *sb, sector_t sector)
+{
+       struct page *page;
+       struct bio *bio;
+
+       page = alloc_page(GFP_KERNEL);
+       if (unlikely(!page))
+               return NULL;
+
+       ClearPageUptodate(page);
+       ClearPageDirty(page);
+       lock_page(page);
+
+       bio = bio_alloc(GFP_KERNEL, 1);
+       if (unlikely(!bio)) {
+               __free_page(page);
+               return NULL;
+       }
+
+       bio->bi_sector = sector * (sb->s_blocksize >> 9);
+       bio->bi_bdev = sb->s_bdev;
+       bio_add_page(bio, page, PAGE_SIZE, 0);
+
+       bio->bi_end_io = end_bio_io_page;
+       bio->bi_private = page;
+       submit_bio(READ_SYNC | (1 << BIO_RW_META), bio);
+       wait_on_page_locked(page);
+       bio_put(bio);
+       if (!PageUptodate(page)) {
+               __free_page(page);
+               return NULL;
+       }
+       return page;
+}
+
+/**
+ * gfs2_read_sb - Read super block
+ * @sdp: The GFS2 superblock
+ * @gl: the glock for the superblock (assumed to be held)
+ * @silent: Don't print message if mount fails
+ *
+ */
+
+int gfs2_read_sb(struct gfs2_sbd *sdp, struct gfs2_glock *gl, int silent)
+{
+       u32 hash_blocks, ind_blocks, leaf_blocks;
+       u32 tmp_blocks;
+       unsigned int x;
+       int error;
+       struct page *page;
+       char *sb;
+
+       page = gfs2_read_super(sdp->sd_vfs, GFS2_SB_ADDR >> sdp->sd_fsb2bb_shift);
+       if (!page) {
+               if (!silent)
+                       fs_err(sdp, "can't read superblock\n");
+               return -EIO;
+       }
+       sb = kmap(page);
+       gfs2_sb_in(&sdp->sd_sb, sb);
+       kunmap(page);
+       __free_page(page);
+
+       error = gfs2_check_sb(sdp, &sdp->sd_sb, silent);
+       if (error)
+               return error;
+
+       sdp->sd_fsb2bb_shift = sdp->sd_sb.sb_bsize_shift -
+                              GFS2_BASIC_BLOCK_SHIFT;
+       sdp->sd_fsb2bb = 1 << 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);
+
+       /* Compute maximum reservation required to add a entry to a directory */
+
+       hash_blocks = DIV_ROUND_UP(sizeof(u64) * (1 << 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;
+       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;
+       gfs2_assert(sdp, sdp->sd_max_jheight <= GFS2_MAX_META_HEIGHT);
+
+       return 0;
+}
+
+/**
+ * gfs2_jindex_hold - Grab a lock on the jindex
+ * @sdp: The GFS2 superblock
+ * @ji_gh: the holder for the jindex glock
+ *
+ * This is very similar to the gfs2_rindex_hold() function, except that
+ * in general we hold the jindex lock for longer periods of time and
+ * we grab it far less frequently (in general) then the rgrp lock.
+ *
+ * Returns: errno
+ */
+
+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_search(sdp->sd_jindex, &name, NULL, 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;
+
+               jd->jd_inode = gfs2_lookupi(sdp->sd_jindex, &name, 1, NULL);
+               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;
+}
+
+/**
+ * gfs2_jindex_free - Clear all the journal index information
+ * @sdp: The GFS2 superblock
+ *
+ */
+
+void gfs2_jindex_free(struct gfs2_sbd *sdp)
+{
+       struct list_head list;
+       struct gfs2_jdesc *jd;
+
+       spin_lock(&sdp->sd_jindex_spin);
+       list_add(&list, &sdp->sd_jindex_list);
+       list_del_init(&sdp->sd_jindex_list);
+       sdp->sd_journals = 0;
+       spin_unlock(&sdp->sd_jindex_spin);
+
+       while (!list_empty(&list)) {
+               jd = list_entry(list.next, struct gfs2_jdesc, jd_list);
+               list_del(&jd->jd_list);
+               iput(jd->jd_inode);
+               kfree(jd);
+       }
+}
+
+static struct gfs2_jdesc *jdesc_find_i(struct list_head *head, unsigned int jid)
+{
+       struct gfs2_jdesc *jd;
+       int found = 0;
+
+       list_for_each_entry(jd, head, jd_list) {
+               if (jd->jd_jid == jid) {
+                       found = 1;
+                       break;
+               }
+       }
+
+       if (!found)
+               jd = NULL;
+
+       return jd;
+}
+
+struct gfs2_jdesc *gfs2_jdesc_find(struct gfs2_sbd *sdp, unsigned int jid)
+{
+       struct gfs2_jdesc *jd;
+
+       spin_lock(&sdp->sd_jindex_spin);
+       jd = jdesc_find_i(&sdp->sd_jindex_list, jid);
+       spin_unlock(&sdp->sd_jindex_spin);
+
+       return jd;
+}
+
+void gfs2_jdesc_make_dirty(struct gfs2_sbd *sdp, unsigned int jid)
+{
+       struct gfs2_jdesc *jd;
+
+       spin_lock(&sdp->sd_jindex_spin);
+       jd = jdesc_find_i(&sdp->sd_jindex_list, jid);
+       if (jd)
+               jd->jd_dirty = 1;
+       spin_unlock(&sdp->sd_jindex_spin);
+}
+
+struct gfs2_jdesc *gfs2_jdesc_find_dirty(struct gfs2_sbd *sdp)
+{
+       struct gfs2_jdesc *jd;
+       int found = 0;
+
+       spin_lock(&sdp->sd_jindex_spin);
+
+       list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
+               if (jd->jd_dirty) {
+                       jd->jd_dirty = 0;
+                       found = 1;
+                       break;
+               }
+       }
+       spin_unlock(&sdp->sd_jindex_spin);
+
+       if (!found)
+               jd = NULL;
+
+       return jd;
+}
+
+int gfs2_jdesc_check(struct gfs2_jdesc *jd)
+{
+       struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
+       struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
+       int ar;
+       int error;
+
+       if (ip->i_di.di_size < (8 << 20) || ip->i_di.di_size > (1 << 30) ||
+           (ip->i_di.di_size & (sdp->sd_sb.sb_bsize - 1))) {
+               gfs2_consist_inode(ip);
+               return -EIO;
+       }
+       jd->jd_blocks = ip->i_di.di_size >> sdp->sd_sb.sb_bsize_shift;
+
+       error = gfs2_write_alloc_required(ip, 0, ip->i_di.di_size, &ar);
+       if (!error && ar) {
+               gfs2_consist_inode(ip);
+               error = -EIO;
+       }
+
+       return error;
+}
+
+/**
+ * gfs2_make_fs_rw - Turn a Read-Only FS into a Read-Write one
+ * @sdp: the filesystem
+ *
+ * Returns: errno
+ */
+
+int gfs2_make_fs_rw(struct gfs2_sbd *sdp)
+{
+       struct gfs2_inode *ip = GFS2_I(sdp->sd_jdesc->jd_inode);
+       struct gfs2_glock *j_gl = ip->i_gl;
+       struct gfs2_holder t_gh;
+       struct gfs2_log_header_host head;
+       int error;
+
+       error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_SHARED, 0, &t_gh);
+       if (error)
+               return error;
+
+       gfs2_meta_cache_flush(ip);
+       j_gl->gl_ops->go_inval(j_gl, DIO_METADATA);
+
+       error = gfs2_find_jhead(sdp->sd_jdesc, &head);
+       if (error)
+               goto fail;
+
+       if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
+               gfs2_consist(sdp);
+               error = -EIO;
+               goto fail;
+       }
+
+       /*  Initialize some head of the log stuff  */
+       sdp->sd_log_sequence = head.lh_sequence + 1;
+       gfs2_log_pointers_init(sdp, head.lh_blkno);
+
+       error = gfs2_quota_init(sdp);
+       if (error)
+               goto fail;
+
+       set_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
+
+       gfs2_glock_dq_uninit(&t_gh);
+
+       return 0;
+
+fail:
+       t_gh.gh_flags |= GL_NOCACHE;
+       gfs2_glock_dq_uninit(&t_gh);
+
+       return error;
+}
+
+/**
+ * gfs2_make_fs_ro - Turn a Read-Write FS into a Read-Only one
+ * @sdp: the filesystem
+ *
+ * Returns: errno
+ */
+
+int gfs2_make_fs_ro(struct gfs2_sbd *sdp)
+{
+       struct gfs2_holder t_gh;
+       int error;
+
+       gfs2_quota_sync(sdp);
+       gfs2_statfs_sync(sdp);
+
+       error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_SHARED, GL_NOCACHE,
+                                  &t_gh);
+       if (error && !test_bit(SDF_SHUTDOWN, &sdp->sd_flags))
+               return error;
+
+       gfs2_meta_syncfs(sdp);
+       gfs2_log_shutdown(sdp);
+
+       clear_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
+
+       if (t_gh.gh_gl)
+               gfs2_glock_dq_uninit(&t_gh);
+
+       gfs2_quota_cleanup(sdp);
+
+       return error;
+}
+
+int gfs2_statfs_init(struct gfs2_sbd *sdp)
+{
+       struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
+       struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
+       struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
+       struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
+       struct buffer_head *m_bh, *l_bh;
+       struct gfs2_holder gh;
+       int error;
+
+       error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE, GL_NOCACHE,
+                                  &gh);
+       if (error)
+               return error;
+
+       error = gfs2_meta_inode_buffer(m_ip, &m_bh);
+       if (error)
+               goto out;
+
+       if (sdp->sd_args.ar_spectator) {
+               spin_lock(&sdp->sd_statfs_spin);
+               gfs2_statfs_change_in(m_sc, m_bh->b_data +
+                                     sizeof(struct gfs2_dinode));
+               spin_unlock(&sdp->sd_statfs_spin);
+       } else {
+               error = gfs2_meta_inode_buffer(l_ip, &l_bh);
+               if (error)
+                       goto out_m_bh;
+
+               spin_lock(&sdp->sd_statfs_spin);
+               gfs2_statfs_change_in(m_sc, m_bh->b_data +
+                                     sizeof(struct gfs2_dinode));
+               gfs2_statfs_change_in(l_sc, l_bh->b_data +
+                                     sizeof(struct gfs2_dinode));
+               spin_unlock(&sdp->sd_statfs_spin);
+
+               brelse(l_bh);
+       }
+
+out_m_bh:
+       brelse(m_bh);
+out:
+       gfs2_glock_dq_uninit(&gh);
+       return 0;
+}
+
+void gfs2_statfs_change(struct gfs2_sbd *sdp, s64 total, s64 free,
+                       s64 dinodes)
+{
+       struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
+       struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
+       struct buffer_head *l_bh;
+       int error;
+
+       error = gfs2_meta_inode_buffer(l_ip, &l_bh);
+       if (error)
+               return;
+
+       mutex_lock(&sdp->sd_statfs_mutex);
+       gfs2_trans_add_bh(l_ip->i_gl, l_bh, 1);
+       mutex_unlock(&sdp->sd_statfs_mutex);
+
+       spin_lock(&sdp->sd_statfs_spin);
+       l_sc->sc_total += total;
+       l_sc->sc_free += free;
+       l_sc->sc_dinodes += dinodes;
+       gfs2_statfs_change_out(l_sc, l_bh->b_data + sizeof(struct gfs2_dinode));
+       spin_unlock(&sdp->sd_statfs_spin);
+
+       brelse(l_bh);
+}
+
+int gfs2_statfs_sync(struct gfs2_sbd *sdp)
+{
+       struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
+       struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
+       struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
+       struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
+       struct gfs2_holder gh;
+       struct buffer_head *m_bh, *l_bh;
+       int error;
+
+       error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE, GL_NOCACHE,
+                                  &gh);
+       if (error)
+               return error;
+
+       error = gfs2_meta_inode_buffer(m_ip, &m_bh);
+       if (error)
+               goto out;
+
+       spin_lock(&sdp->sd_statfs_spin);
+       gfs2_statfs_change_in(m_sc, m_bh->b_data +
+                             sizeof(struct gfs2_dinode));
+       if (!l_sc->sc_total && !l_sc->sc_free && !l_sc->sc_dinodes) {
+               spin_unlock(&sdp->sd_statfs_spin);
+               goto out_bh;
+       }
+       spin_unlock(&sdp->sd_statfs_spin);
+
+       error = gfs2_meta_inode_buffer(l_ip, &l_bh);
+       if (error)
+               goto out_bh;
+
+       error = gfs2_trans_begin(sdp, 2 * RES_DINODE, 0);
+       if (error)
+               goto out_bh2;
+
+       mutex_lock(&sdp->sd_statfs_mutex);
+       gfs2_trans_add_bh(l_ip->i_gl, l_bh, 1);
+       mutex_unlock(&sdp->sd_statfs_mutex);
+
+       spin_lock(&sdp->sd_statfs_spin);
+       m_sc->sc_total += l_sc->sc_total;
+       m_sc->sc_free += l_sc->sc_free;
+       m_sc->sc_dinodes += l_sc->sc_dinodes;
+       memset(l_sc, 0, sizeof(struct gfs2_statfs_change));
+       memset(l_bh->b_data + sizeof(struct gfs2_dinode),
+              0, sizeof(struct gfs2_statfs_change));
+       spin_unlock(&sdp->sd_statfs_spin);
+
+       gfs2_trans_add_bh(m_ip->i_gl, m_bh, 1);
+       gfs2_statfs_change_out(m_sc, m_bh->b_data + sizeof(struct gfs2_dinode));
+
+       gfs2_trans_end(sdp);
+
+out_bh2:
+       brelse(l_bh);
+out_bh:
+       brelse(m_bh);
+out:
+       gfs2_glock_dq_uninit(&gh);
+       return error;
+}
+
+/**
+ * gfs2_statfs_i - Do a statfs
+ * @sdp: the filesystem
+ * @sg: the sg structure
+ *
+ * Returns: errno
+ */
+
+int gfs2_statfs_i(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host *sc)
+{
+       struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
+       struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
+
+       spin_lock(&sdp->sd_statfs_spin);
+
+       *sc = *m_sc;
+       sc->sc_total += l_sc->sc_total;
+       sc->sc_free += l_sc->sc_free;
+       sc->sc_dinodes += l_sc->sc_dinodes;
+
+       spin_unlock(&sdp->sd_statfs_spin);
+
+       if (sc->sc_free < 0)
+               sc->sc_free = 0;
+       if (sc->sc_free > sc->sc_total)
+               sc->sc_free = sc->sc_total;
+       if (sc->sc_dinodes < 0)
+               sc->sc_dinodes = 0;
+
+       return 0;
+}
+
+/**
+ * statfs_fill - fill in the sg for a given RG
+ * @rgd: the RG
+ * @sc: the sc structure
+ *
+ * Returns: 0 on success, -ESTALE if the LVB is invalid
+ */
+
+static int statfs_slow_fill(struct gfs2_rgrpd *rgd,
+                           struct gfs2_statfs_change_host *sc)
+{
+       gfs2_rgrp_verify(rgd);
+       sc->sc_total += rgd->rd_ri.ri_data;
+       sc->sc_free += rgd->rd_rg.rg_free;
+       sc->sc_dinodes += rgd->rd_rg.rg_dinodes;
+       return 0;
+}
+
+/**
+ * gfs2_statfs_slow - Stat a filesystem using asynchronous locking
+ * @sdp: the filesystem
+ * @sc: the sc info that will be returned
+ *
+ * Any error (other than a signal) will cause this routine to fall back
+ * to the synchronous version.
+ *
+ * FIXME: This really shouldn't busy wait like this.
+ *
+ * Returns: errno
+ */
+
+int gfs2_statfs_slow(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host *sc)
+{
+       struct gfs2_holder ri_gh;
+       struct gfs2_rgrpd *rgd_next;
+       struct gfs2_holder *gha, *gh;
+       unsigned int slots = 64;
+       unsigned int x;
+       int done;
+       int error = 0, err;
+
+       memset(sc, 0, sizeof(struct gfs2_statfs_change_host));
+       gha = kcalloc(slots, sizeof(struct gfs2_holder), GFP_KERNEL);
+       if (!gha)
+               return -ENOMEM;
+
+       error = gfs2_rindex_hold(sdp, &ri_gh);
+       if (error)
+               goto out;
+
+       rgd_next = gfs2_rgrpd_get_first(sdp);
+
+       for (;;) {
+               done = 1;
+
+               for (x = 0; x < slots; x++) {
+                       gh = gha + x;
+
+                       if (gh->gh_gl && gfs2_glock_poll(gh)) {
+                               err = gfs2_glock_wait(gh);
+                               if (err) {
+                                       gfs2_holder_uninit(gh);
+                                       error = err;
+                               } else {
+                                       if (!error)
+                                               error = statfs_slow_fill(
+                                                       gh->gh_gl->gl_object, sc);
+                                       gfs2_glock_dq_uninit(gh);
+                               }
+                       }
+
+                       if (gh->gh_gl)
+                               done = 0;
+                       else if (rgd_next && !error) {
+                               error = gfs2_glock_nq_init(rgd_next->rd_gl,
+                                                          LM_ST_SHARED,
+                                                          GL_ASYNC,
+                                                          gh);
+                               rgd_next = gfs2_rgrpd_get_next(rgd_next);
+                               done = 0;
+                       }
+
+                       if (signal_pending(current))
+                               error = -ERESTARTSYS;
+               }
+
+               if (done)
+                       break;
+
+               yield();
+       }
+
+       gfs2_glock_dq_uninit(&ri_gh);
+
+out:
+       kfree(gha);
+       return error;
+}
+
+struct lfcc {
+       struct list_head list;
+       struct gfs2_holder gh;
+};
+
+/**
+ * gfs2_lock_fs_check_clean - Stop all writes to the FS and check that all
+ *                            journals are clean
+ * @sdp: the file system
+ * @state: the state to put the transaction lock into
+ * @t_gh: the hold on the transaction lock
+ *
+ * Returns: errno
+ */
+
+static int gfs2_lock_fs_check_clean(struct gfs2_sbd *sdp,
+                                   struct gfs2_holder *t_gh)
+{
+       struct gfs2_inode *ip;
+       struct gfs2_holder ji_gh;
+       struct gfs2_jdesc *jd;
+       struct lfcc *lfcc;
+       LIST_HEAD(list);
+       struct gfs2_log_header_host lh;
+       int error;
+
+       error = gfs2_jindex_hold(sdp, &ji_gh);
+       if (error)
+               return error;
+
+       list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
+               lfcc = kmalloc(sizeof(struct lfcc), GFP_KERNEL);
+               if (!lfcc) {
+                       error = -ENOMEM;
+                       goto out;
+               }
+               ip = GFS2_I(jd->jd_inode);
+               error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &lfcc->gh);
+               if (error) {
+                       kfree(lfcc);
+                       goto out;
+               }
+               list_add(&lfcc->list, &list);
+       }
+
+       error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_DEFERRED,
+                              LM_FLAG_PRIORITY | GL_NOCACHE,
+                              t_gh);
+
+       list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
+               error = gfs2_jdesc_check(jd);
+               if (error)
+                       break;
+               error = gfs2_find_jhead(jd, &lh);
+               if (error)
+                       break;
+               if (!(lh.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
+                       error = -EBUSY;
+                       break;
+               }
+       }
+
+       if (error)
+               gfs2_glock_dq_uninit(t_gh);
+
+out:
+       while (!list_empty(&list)) {
+               lfcc = list_entry(list.next, struct lfcc, list);
+               list_del(&lfcc->list);
+               gfs2_glock_dq_uninit(&lfcc->gh);
+               kfree(lfcc);
+       }
+       gfs2_glock_dq_uninit(&ji_gh);
+       return error;
+}
+
+/**
+ * gfs2_freeze_fs - freezes the file system
+ * @sdp: the file system
+ *
+ * This function flushes data and meta data for all machines by
+ * aquiring the transaction log exclusively.  All journals are
+ * ensured to be in a clean state as well.
+ *
+ * Returns: errno
+ */
+
+int gfs2_freeze_fs(struct gfs2_sbd *sdp)
+{
+       int error = 0;
+
+       mutex_lock(&sdp->sd_freeze_lock);
+
+       if (!sdp->sd_freeze_count++) {
+               error = gfs2_lock_fs_check_clean(sdp, &sdp->sd_freeze_gh);
+               if (error)
+                       sdp->sd_freeze_count--;
+       }
+
+       mutex_unlock(&sdp->sd_freeze_lock);
+
+       return error;
+}
+
+/**
+ * gfs2_unfreeze_fs - unfreezes the file system
+ * @sdp: the file system
+ *
+ * This function allows the file system to proceed by unlocking
+ * the exclusively held transaction lock.  Other GFS2 nodes are
+ * now free to acquire the lock shared and go on with their lives.
+ *
+ */
+
+void gfs2_unfreeze_fs(struct gfs2_sbd *sdp)
+{
+       mutex_lock(&sdp->sd_freeze_lock);
+
+       if (sdp->sd_freeze_count && !--sdp->sd_freeze_count)
+               gfs2_glock_dq_uninit(&sdp->sd_freeze_gh);
+
+       mutex_unlock(&sdp->sd_freeze_lock);
+}
+