1 files changed, 687 insertions, 0 deletions

diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
new file mode 100644
index 000000000000..554fe5bd1b72
--- /dev/null
+++ b/fs/gfs2/log.c
@@ -0,0 +1,687 @@
+/*
+ * 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/gfs2_ondisk.h>
+#include <linux/crc32.h>
+#include <linux/lm_interface.h>
+
+#include "gfs2.h"
+#include "incore.h"
+#include "bmap.h"
+#include "glock.h"
+#include "log.h"
+#include "lops.h"
+#include "meta_io.h"
+#include "util.h"
+#include "dir.h"
+
+#define PULL 1
+
+/**
+ * gfs2_struct2blk - compute stuff
+ * @sdp: the filesystem
+ * @nstruct: the number of structures
+ * @ssize: the size of the structures
+ *
+ * Compute the number of log descriptor blocks needed to hold a certain number
+ * of structures of a certain size.
+ *
+ * Returns: the number of blocks needed (minimum is always 1)
+ */
+
+unsigned int gfs2_struct2blk(struct gfs2_sbd *sdp, unsigned int nstruct,
+			     unsigned int ssize)
+{
+	unsigned int blks;
+	unsigned int first, second;
+
+	blks = 1;
+	first = (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_log_descriptor)) / ssize;
+
+	if (nstruct > first) {
+		second = (sdp->sd_sb.sb_bsize -
+			  sizeof(struct gfs2_meta_header)) / ssize;
+		blks += DIV_ROUND_UP(nstruct - first, second);
+	}
+
+	return blks;
+}
+
+/**
+ * gfs2_ail1_start_one - Start I/O on a part of the AIL
+ * @sdp: the filesystem
+ * @tr: the part of the AIL
+ *
+ */
+
+static void gfs2_ail1_start_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
+{
+	struct gfs2_bufdata *bd, *s;
+	struct buffer_head *bh;
+	int retry;
+
+	BUG_ON(!spin_is_locked(&sdp->sd_log_lock));
+
+	do {
+		retry = 0;
+
+		list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list,
+						 bd_ail_st_list) {
+			bh = bd->bd_bh;
+
+			gfs2_assert(sdp, bd->bd_ail == ai);
+
+			if (!buffer_busy(bh)) {
+				if (!buffer_uptodate(bh)) {
+					gfs2_log_unlock(sdp);
+					gfs2_io_error_bh(sdp, bh);
+					gfs2_log_lock(sdp);
+				}
+				list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list);
+				continue;
+			}
+
+			if (!buffer_dirty(bh))
+				continue;
+
+			list_move(&bd->bd_ail_st_list, &ai->ai_ail1_list);
+
+			gfs2_log_unlock(sdp);
+			wait_on_buffer(bh);
+			ll_rw_block(WRITE, 1, &bh);
+			gfs2_log_lock(sdp);
+
+			retry = 1;
+			break;
+		}
+	} while (retry);
+}
+
+/**
+ * gfs2_ail1_empty_one - Check whether or not a trans in the AIL has been synced
+ * @sdp: the filesystem
+ * @ai: the AIL entry
+ *
+ */
+
+static int gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai, int flags)
+{
+	struct gfs2_bufdata *bd, *s;
+	struct buffer_head *bh;
+
+	list_for_each_entry_safe_reverse(bd, s, &ai->ai_ail1_list,
+					 bd_ail_st_list) {
+		bh = bd->bd_bh;
+
+		gfs2_assert(sdp, bd->bd_ail == ai);
+
+		if (buffer_busy(bh)) {
+			if (flags & DIO_ALL)
+				continue;
+			else
+				break;
+		}
+
+		if (!buffer_uptodate(bh))
+			gfs2_io_error_bh(sdp, bh);
+
+		list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list);
+	}
+
+	return list_empty(&ai->ai_ail1_list);
+}
+
+void gfs2_ail1_start(struct gfs2_sbd *sdp, int flags)
+{
+	struct list_head *head = &sdp->sd_ail1_list;
+	u64 sync_gen;
+	struct list_head *first;
+	struct gfs2_ail *first_ai, *ai, *tmp;
+	int done = 0;
+
+	gfs2_log_lock(sdp);
+	if (list_empty(head)) {
+		gfs2_log_unlock(sdp);
+		return;
+	}
+	sync_gen = sdp->sd_ail_sync_gen++;
+
+	first = head->prev;
+	first_ai = list_entry(first, struct gfs2_ail, ai_list);
+	first_ai->ai_sync_gen = sync_gen;
+	gfs2_ail1_start_one(sdp, first_ai); /* This may drop log lock */
+
+	if (flags & DIO_ALL)
+		first = NULL;
+
+	while(!done) {
+		if (first && (head->prev != first ||
+			      gfs2_ail1_empty_one(sdp, first_ai, 0)))
+			break;
+
+		done = 1;
+		list_for_each_entry_safe_reverse(ai, tmp, head, ai_list) {
+			if (ai->ai_sync_gen >= sync_gen)
+				continue;
+			ai->ai_sync_gen = sync_gen;
+			gfs2_ail1_start_one(sdp, ai); /* This may drop log lock */
+			done = 0;
+			break;
+		}
+	}
+
+	gfs2_log_unlock(sdp);
+}
+
+int gfs2_ail1_empty(struct gfs2_sbd *sdp, int flags)
+{
+	struct gfs2_ail *ai, *s;
+	int ret;
+
+	gfs2_log_lock(sdp);
+
+	list_for_each_entry_safe_reverse(ai, s, &sdp->sd_ail1_list, ai_list) {
+		if (gfs2_ail1_empty_one(sdp, ai, flags))
+			list_move(&ai->ai_list, &sdp->sd_ail2_list);
+		else if (!(flags & DIO_ALL))
+			break;
+	}
+
+	ret = list_empty(&sdp->sd_ail1_list);
+
+	gfs2_log_unlock(sdp);
+
+	return ret;
+}
+
+
+/**
+ * gfs2_ail2_empty_one - Check whether or not a trans in the AIL has been synced
+ * @sdp: the filesystem
+ * @ai: the AIL entry
+ *
+ */
+
+static void gfs2_ail2_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
+{
+	struct list_head *head = &ai->ai_ail2_list;
+	struct gfs2_bufdata *bd;
+
+	while (!list_empty(head)) {
+		bd = list_entry(head->prev, struct gfs2_bufdata,
+				bd_ail_st_list);
+		gfs2_assert(sdp, bd->bd_ail == ai);
+		bd->bd_ail = NULL;
+		list_del(&bd->bd_ail_st_list);
+		list_del(&bd->bd_ail_gl_list);
+		atomic_dec(&bd->bd_gl->gl_ail_count);
+		brelse(bd->bd_bh);
+	}
+}
+
+static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail)
+{
+	struct gfs2_ail *ai, *safe;
+	unsigned int old_tail = sdp->sd_log_tail;
+	int wrap = (new_tail < old_tail);
+	int a, b, rm;
+
+	gfs2_log_lock(sdp);
+
+	list_for_each_entry_safe(ai, safe, &sdp->sd_ail2_list, ai_list) {
+		a = (old_tail <= ai->ai_first);
+		b = (ai->ai_first < new_tail);
+		rm = (wrap) ? (a || b) : (a && b);
+		if (!rm)
+			continue;
+
+		gfs2_ail2_empty_one(sdp, ai);
+		list_del(&ai->ai_list);
+		gfs2_assert_warn(sdp, list_empty(&ai->ai_ail1_list));
+		gfs2_assert_warn(sdp, list_empty(&ai->ai_ail2_list));
+		kfree(ai);
+	}
+
+	gfs2_log_unlock(sdp);
+}
+
+/**
+ * gfs2_log_reserve - Make a log reservation
+ * @sdp: The GFS2 superblock
+ * @blks: The number of blocks to reserve
+ *
+ * Returns: errno
+ */
+
+int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks)
+{
+	unsigned int try = 0;
+
+	if (gfs2_assert_warn(sdp, blks) ||
+	    gfs2_assert_warn(sdp, blks <= sdp->sd_jdesc->jd_blocks))
+		return -EINVAL;
+
+	mutex_lock(&sdp->sd_log_reserve_mutex);
+	gfs2_log_lock(sdp);
+	while(sdp->sd_log_blks_free <= blks) {
+		gfs2_log_unlock(sdp);
+		gfs2_ail1_empty(sdp, 0);
+		gfs2_log_flush(sdp, NULL);
+
+		if (try++)
+			gfs2_ail1_start(sdp, 0);
+		gfs2_log_lock(sdp);
+	}
+	sdp->sd_log_blks_free -= blks;
+	gfs2_log_unlock(sdp);
+	mutex_unlock(&sdp->sd_log_reserve_mutex);
+
+	down_read(&sdp->sd_log_flush_lock);
+
+	return 0;
+}
+
+/**
+ * gfs2_log_release - Release a given number of log blocks
+ * @sdp: The GFS2 superblock
+ * @blks: The number of blocks
+ *
+ */
+
+void gfs2_log_release(struct gfs2_sbd *sdp, unsigned int blks)
+{
+
+	gfs2_log_lock(sdp);
+	sdp->sd_log_blks_free += blks;
+	gfs2_assert_withdraw(sdp,
+			     sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks);
+	gfs2_log_unlock(sdp);
+	up_read(&sdp->sd_log_flush_lock);
+}
+
+static u64 log_bmap(struct gfs2_sbd *sdp, unsigned int lbn)
+{
+	int error;
+	struct buffer_head bh_map;
+
+	error = gfs2_block_map(sdp->sd_jdesc->jd_inode, lbn, 0, &bh_map, 1);
+	if (error || !bh_map.b_blocknr)
+		printk(KERN_INFO "error=%d, dbn=%llu lbn=%u", error, bh_map.b_blocknr, lbn);
+	gfs2_assert_withdraw(sdp, !error && bh_map.b_blocknr);
+
+	return bh_map.b_blocknr;
+}
+
+/**
+ * log_distance - Compute distance between two journal blocks
+ * @sdp: The GFS2 superblock
+ * @newer: The most recent journal block of the pair
+ * @older: The older journal block of the pair
+ *
+ *   Compute the distance (in the journal direction) between two
+ *   blocks in the journal
+ *
+ * Returns: the distance in blocks
+ */
+
+static inline unsigned int log_distance(struct gfs2_sbd *sdp, unsigned int newer,
+					unsigned int older)
+{
+	int dist;
+
+	dist = newer - older;
+	if (dist < 0)
+		dist += sdp->sd_jdesc->jd_blocks;
+
+	return dist;
+}
+
+static unsigned int current_tail(struct gfs2_sbd *sdp)
+{
+	struct gfs2_ail *ai;
+	unsigned int tail;
+
+	gfs2_log_lock(sdp);
+
+	if (list_empty(&sdp->sd_ail1_list)) {
+		tail = sdp->sd_log_head;
+	} else {
+		ai = list_entry(sdp->sd_ail1_list.prev, struct gfs2_ail, ai_list);
+		tail = ai->ai_first;
+	}
+
+	gfs2_log_unlock(sdp);
+
+	return tail;
+}
+
+static inline void log_incr_head(struct gfs2_sbd *sdp)
+{
+	if (sdp->sd_log_flush_head == sdp->sd_log_tail)
+		gfs2_assert_withdraw(sdp, sdp->sd_log_flush_head == sdp->sd_log_head);
+
+	if (++sdp->sd_log_flush_head == sdp->sd_jdesc->jd_blocks) {
+		sdp->sd_log_flush_head = 0;
+		sdp->sd_log_flush_wrapped = 1;
+	}
+}
+
+/**
+ * gfs2_log_get_buf - Get and initialize a buffer to use for log control data
+ * @sdp: The GFS2 superblock
+ *
+ * Returns: the buffer_head
+ */
+
+struct buffer_head *gfs2_log_get_buf(struct gfs2_sbd *sdp)
+{
+	u64 blkno = log_bmap(sdp, sdp->sd_log_flush_head);
+	struct gfs2_log_buf *lb;
+	struct buffer_head *bh;
+
+	lb = kzalloc(sizeof(struct gfs2_log_buf), GFP_NOFS | __GFP_NOFAIL);
+	list_add(&lb->lb_list, &sdp->sd_log_flush_list);
+
+	bh = lb->lb_bh = sb_getblk(sdp->sd_vfs, blkno);
+	lock_buffer(bh);
+	memset(bh->b_data, 0, bh->b_size);
+	set_buffer_uptodate(bh);
+	clear_buffer_dirty(bh);
+	unlock_buffer(bh);
+
+	log_incr_head(sdp);
+
+	return bh;
+}
+
+/**
+ * gfs2_log_fake_buf - Build a fake buffer head to write metadata buffer to log
+ * @sdp: the filesystem
+ * @data: the data the buffer_head should point to
+ *
+ * Returns: the log buffer descriptor
+ */
+
+struct buffer_head *gfs2_log_fake_buf(struct gfs2_sbd *sdp,
+				      struct buffer_head *real)
+{
+	u64 blkno = log_bmap(sdp, sdp->sd_log_flush_head);
+	struct gfs2_log_buf *lb;
+	struct buffer_head *bh;
+
+	lb = kzalloc(sizeof(struct gfs2_log_buf), GFP_NOFS | __GFP_NOFAIL);
+	list_add(&lb->lb_list, &sdp->sd_log_flush_list);
+	lb->lb_real = real;
+
+	bh = lb->lb_bh = alloc_buffer_head(GFP_NOFS | __GFP_NOFAIL);
+	atomic_set(&bh->b_count, 1);
+	bh->b_state = (1 << BH_Mapped) | (1 << BH_Uptodate);
+	set_bh_page(bh, real->b_page, bh_offset(real));
+	bh->b_blocknr = blkno;
+	bh->b_size = sdp->sd_sb.sb_bsize;
+	bh->b_bdev = sdp->sd_vfs->s_bdev;
+
+	log_incr_head(sdp);
+
+	return bh;
+}
+
+static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail, int pull)
+{
+	unsigned int dist = log_distance(sdp, new_tail, sdp->sd_log_tail);
+
+	ail2_empty(sdp, new_tail);
+
+	gfs2_log_lock(sdp);
+	sdp->sd_log_blks_free += dist - (pull ? 1 : 0);
+	gfs2_assert_withdraw(sdp, sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks);
+	gfs2_log_unlock(sdp);
+
+	sdp->sd_log_tail = new_tail;
+}
+
+/**
+ * log_write_header - Get and initialize a journal header buffer
+ * @sdp: The GFS2 superblock
+ *
+ * Returns: the initialized log buffer descriptor
+ */
+
+static void log_write_header(struct gfs2_sbd *sdp, u32 flags, int pull)
+{
+	u64 blkno = log_bmap(sdp, sdp->sd_log_flush_head);
+	struct buffer_head *bh;
+	struct gfs2_log_header *lh;
+	unsigned int tail;
+	u32 hash;
+
+	bh = sb_getblk(sdp->sd_vfs, blkno);
+	lock_buffer(bh);
+	memset(bh->b_data, 0, bh->b_size);
+	set_buffer_uptodate(bh);
+	clear_buffer_dirty(bh);
+	unlock_buffer(bh);
+
+	gfs2_ail1_empty(sdp, 0);
+	tail = current_tail(sdp);
+
+	lh = (struct gfs2_log_header *)bh->b_data;
+	memset(lh, 0, sizeof(struct gfs2_log_header));
+	lh->lh_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
+	lh->lh_header.mh_type = cpu_to_be32(GFS2_METATYPE_LH);
+	lh->lh_header.mh_format = cpu_to_be32(GFS2_FORMAT_LH);
+	lh->lh_sequence = cpu_to_be64(sdp->sd_log_sequence++);
+	lh->lh_flags = cpu_to_be32(flags);
+	lh->lh_tail = cpu_to_be32(tail);
+	lh->lh_blkno = cpu_to_be32(sdp->sd_log_flush_head);
+	hash = gfs2_disk_hash(bh->b_data, sizeof(struct gfs2_log_header));
+	lh->lh_hash = cpu_to_be32(hash);
+
+	set_buffer_dirty(bh);
+	if (sync_dirty_buffer(bh))
+		gfs2_io_error_bh(sdp, bh);
+	brelse(bh);
+
+	if (sdp->sd_log_tail != tail)
+		log_pull_tail(sdp, tail, pull);
+	else
+		gfs2_assert_withdraw(sdp, !pull);
+
+	sdp->sd_log_idle = (tail == sdp->sd_log_flush_head);
+	log_incr_head(sdp);
+}
+
+static void log_flush_commit(struct gfs2_sbd *sdp)
+{
+	struct list_head *head = &sdp->sd_log_flush_list;
+	struct gfs2_log_buf *lb;
+	struct buffer_head *bh;
+
+	while (!list_empty(head)) {
+		lb = list_entry(head->next, struct gfs2_log_buf, lb_list);
+		list_del(&lb->lb_list);
+		bh = lb->lb_bh;
+
+		wait_on_buffer(bh);
+		if (!buffer_uptodate(bh))
+			gfs2_io_error_bh(sdp, bh);
+		if (lb->lb_real) {
+			while (atomic_read(&bh->b_count) != 1)  /* Grrrr... */
+				schedule();
+			free_buffer_head(bh);
+		} else
+			brelse(bh);
+		kfree(lb);
+	}
+
+	log_write_header(sdp, 0, 0);
+}
+
+/**
+ * gfs2_log_flush - flush incore transaction(s)
+ * @sdp: the filesystem
+ * @gl: The glock structure to flush.  If NULL, flush the whole incore log
+ *
+ */
+
+void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
+{
+	struct gfs2_ail *ai;
+
+	down_write(&sdp->sd_log_flush_lock);
+
+	if (gl) {
+		gfs2_log_lock(sdp);
+		if (list_empty(&gl->gl_le.le_list)) {
+			gfs2_log_unlock(sdp);
+			up_write(&sdp->sd_log_flush_lock);
+			return;
+		}
+		gfs2_log_unlock(sdp);
+	}
+
+	ai = kzalloc(sizeof(struct gfs2_ail), GFP_NOFS | __GFP_NOFAIL);
+	INIT_LIST_HEAD(&ai->ai_ail1_list);
+	INIT_LIST_HEAD(&ai->ai_ail2_list);
+
+	gfs2_assert_withdraw(sdp, sdp->sd_log_num_buf == sdp->sd_log_commited_buf);
+	gfs2_assert_withdraw(sdp,
+			sdp->sd_log_num_revoke == sdp->sd_log_commited_revoke);
+
+	sdp->sd_log_flush_head = sdp->sd_log_head;
+	sdp->sd_log_flush_wrapped = 0;
+	ai->ai_first = sdp->sd_log_flush_head;
+
+	lops_before_commit(sdp);
+	if (!list_empty(&sdp->sd_log_flush_list))
+		log_flush_commit(sdp);
+	else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle)
+		log_write_header(sdp, 0, PULL);
+	lops_after_commit(sdp, ai);
+	sdp->sd_log_head = sdp->sd_log_flush_head;
+
+	sdp->sd_log_blks_free -= sdp->sd_log_num_hdrs;
+
+	sdp->sd_log_blks_reserved = 0;
+	sdp->sd_log_commited_buf = 0;
+	sdp->sd_log_num_hdrs = 0;
+	sdp->sd_log_commited_revoke = 0;
+
+	gfs2_log_lock(sdp);
+	if (!list_empty(&ai->ai_ail1_list)) {
+		list_add(&ai->ai_list, &sdp->sd_ail1_list);
+		ai = NULL;
+	}
+	gfs2_log_unlock(sdp);
+
+	sdp->sd_vfs->s_dirt = 0;
+	up_write(&sdp->sd_log_flush_lock);
+
+	kfree(ai);
+}
+
+static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
+{
+	unsigned int reserved = 0;
+	unsigned int old;
+
+	gfs2_log_lock(sdp);
+
+	sdp->sd_log_commited_buf += tr->tr_num_buf_new - tr->tr_num_buf_rm;
+	gfs2_assert_withdraw(sdp, ((int)sdp->sd_log_commited_buf) >= 0);
+	sdp->sd_log_commited_revoke += tr->tr_num_revoke - tr->tr_num_revoke_rm;
+	gfs2_assert_withdraw(sdp, ((int)sdp->sd_log_commited_revoke) >= 0);
+
+	if (sdp->sd_log_commited_buf)
+		reserved += sdp->sd_log_commited_buf;
+	if (sdp->sd_log_commited_revoke)
+		reserved += gfs2_struct2blk(sdp, sdp->sd_log_commited_revoke,
+					    sizeof(u64));
+	if (reserved)
+		reserved++;
+
+	old = sdp->sd_log_blks_free;
+	sdp->sd_log_blks_free += tr->tr_reserved -
+				 (reserved - sdp->sd_log_blks_reserved);
+
+	gfs2_assert_withdraw(sdp, sdp->sd_log_blks_free >= old);
+	gfs2_assert_withdraw(sdp,
+			     sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks +
+			     sdp->sd_log_num_hdrs);
+
+	sdp->sd_log_blks_reserved = reserved;
+
+	gfs2_log_unlock(sdp);
+}
+
+/**
+ * gfs2_log_commit - Commit a transaction to the log
+ * @sdp: the filesystem
+ * @tr: the transaction
+ *
+ * Returns: errno
+ */
+
+void gfs2_log_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
+{
+	log_refund(sdp, tr);
+	lops_incore_commit(sdp, tr);
+
+	sdp->sd_vfs->s_dirt = 1;
+	up_read(&sdp->sd_log_flush_lock);
+
+	gfs2_log_lock(sdp);
+	if (sdp->sd_log_num_buf > gfs2_tune_get(sdp, gt_incore_log_blocks)) {
+		gfs2_log_unlock(sdp);
+		gfs2_log_flush(sdp, NULL);
+	} else {
+		gfs2_log_unlock(sdp);
+	}
+}
+
+/**
+ * gfs2_log_shutdown - write a shutdown header into a journal
+ * @sdp: the filesystem
+ *
+ */
+
+void gfs2_log_shutdown(struct gfs2_sbd *sdp)
+{
+	down_write(&sdp->sd_log_flush_lock);
+
+	gfs2_assert_withdraw(sdp, !sdp->sd_log_blks_reserved);
+	gfs2_assert_withdraw(sdp, !sdp->sd_log_num_gl);
+	gfs2_assert_withdraw(sdp, !sdp->sd_log_num_buf);
+	gfs2_assert_withdraw(sdp, !sdp->sd_log_num_jdata);
+	gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);
+	gfs2_assert_withdraw(sdp, !sdp->sd_log_num_rg);
+	gfs2_assert_withdraw(sdp, !sdp->sd_log_num_databuf);
+	gfs2_assert_withdraw(sdp, !sdp->sd_log_num_hdrs);
+	gfs2_assert_withdraw(sdp, list_empty(&sdp->sd_ail1_list));
+
+	sdp->sd_log_flush_head = sdp->sd_log_head;
+	sdp->sd_log_flush_wrapped = 0;
+
+	log_write_header(sdp, GFS2_LOG_HEAD_UNMOUNT, 0);
+
+	gfs2_assert_warn(sdp, sdp->sd_log_blks_free == sdp->sd_jdesc->jd_blocks);
+	gfs2_assert_warn(sdp, sdp->sd_log_head == sdp->sd_log_tail);
+	gfs2_assert_warn(sdp, list_empty(&sdp->sd_ail2_list));
+
+	sdp->sd_log_head = sdp->sd_log_flush_head;
+	sdp->sd_log_tail = sdp->sd_log_head;
+
+	up_write(&sdp->sd_log_flush_lock);
+}
+