1 files changed, 102 insertions, 27 deletions

diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 291415ddfe51..f49a12e24086 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -83,6 +83,11 @@ static void gfs2_ail1_start_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
 
 			gfs2_assert(sdp, bd->bd_ail == ai);
 
+			if (!bh){
+				list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list);
+                                continue;
+                        }
+
 			if (!buffer_busy(bh)) {
 				if (!buffer_uptodate(bh)) {
 					gfs2_log_unlock(sdp);
@@ -125,6 +130,11 @@ static int gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai, int fl
 					 bd_ail_st_list) {
 		bh = bd->bd_bh;
 
+		if (!bh){
+			list_move(&bd->bd_ail_st_list, &ai->ai_ail2_list);
+			continue;
+		}
+
 		gfs2_assert(sdp, bd->bd_ail == ai);
 
 		if (buffer_busy(bh)) {
@@ -262,8 +272,8 @@ static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail)
  * @sdp: The GFS2 superblock
  * @blks: The number of blocks to reserve
  *
- * Note that we never give out the last 6 blocks of the journal. Thats
- * due to the fact that there is are a small number of header blocks
+ * Note that we never give out the last few blocks of the journal. Thats
+ * due to the fact that there is a small number of header blocks
  * associated with each log flush. The exact number can't be known until
  * flush time, so we ensure that we have just enough free blocks at all
  * times to avoid running out during a log flush.
@@ -274,6 +284,7 @@ static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail)
 int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks)
 {
 	unsigned int try = 0;
+	unsigned reserved_blks = 6 * (4096 / sdp->sd_vfs->s_blocksize);
 
 	if (gfs2_assert_warn(sdp, blks) ||
 	    gfs2_assert_warn(sdp, blks <= sdp->sd_jdesc->jd_blocks))
@@ -281,7 +292,7 @@ int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks)
 
 	mutex_lock(&sdp->sd_log_reserve_mutex);
 	gfs2_log_lock(sdp);
-	while(sdp->sd_log_blks_free <= (blks + 6)) {
+	while(sdp->sd_log_blks_free <= (blks + reserved_blks)) {
 		gfs2_log_unlock(sdp);
 		gfs2_ail1_empty(sdp, 0);
 		gfs2_log_flush(sdp, NULL);
@@ -357,6 +368,58 @@ static inline unsigned int log_distance(struct gfs2_sbd *sdp, unsigned int newer
 	return dist;
 }
 
+/**
+ * calc_reserved - Calculate the number of blocks to reserve when
+ *                 refunding a transaction's unused buffers.
+ * @sdp: The GFS2 superblock
+ *
+ * This is complex.  We need to reserve room for all our currently used
+ * metadata buffers (e.g. normal file I/O rewriting file time stamps) and 
+ * all our journaled data buffers for journaled files (e.g. files in the 
+ * meta_fs like rindex, or files for which chattr +j was done.)
+ * If we don't reserve enough space, gfs2_log_refund and gfs2_log_flush
+ * will count it as free space (sd_log_blks_free) and corruption will follow.
+ *
+ * We can have metadata bufs and jdata bufs in the same journal.  So each
+ * type gets its own log header, for which we need to reserve a block.
+ * In fact, each type has the potential for needing more than one header 
+ * in cases where we have more buffers than will fit on a journal page.
+ * Metadata journal entries take up half the space of journaled buffer entries.
+ * Thus, metadata entries have buf_limit (502) and journaled buffers have
+ * databuf_limit (251) before they cause a wrap around.
+ *
+ * Also, we need to reserve blocks for revoke journal entries and one for an
+ * overall header for the lot.
+ *
+ * Returns: the number of blocks reserved
+ */
+static unsigned int calc_reserved(struct gfs2_sbd *sdp)
+{
+	unsigned int reserved = 0;
+	unsigned int mbuf_limit, metabufhdrs_needed;
+	unsigned int dbuf_limit, databufhdrs_needed;
+	unsigned int revokes = 0;
+
+	mbuf_limit = buf_limit(sdp);
+	metabufhdrs_needed = (sdp->sd_log_commited_buf +
+			      (mbuf_limit - 1)) / mbuf_limit;
+	dbuf_limit = databuf_limit(sdp);
+	databufhdrs_needed = (sdp->sd_log_commited_databuf +
+			      (dbuf_limit - 1)) / dbuf_limit;
+
+	if (sdp->sd_log_commited_revoke)
+		revokes = gfs2_struct2blk(sdp, sdp->sd_log_commited_revoke,
+					  sizeof(u64));
+
+	reserved = sdp->sd_log_commited_buf + metabufhdrs_needed +
+		sdp->sd_log_commited_databuf + databufhdrs_needed +
+		revokes;
+	/* One for the overall header */
+	if (reserved)
+		reserved++;
+	return reserved;
+}
+
 static unsigned int current_tail(struct gfs2_sbd *sdp)
 {
 	struct gfs2_ail *ai;
@@ -447,14 +510,14 @@ struct buffer_head *gfs2_log_fake_buf(struct gfs2_sbd *sdp,
 	return bh;
 }
 
-static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail, int pull)
+static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail)
 {
 	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);
+	sdp->sd_log_blks_free += dist;
 	gfs2_assert_withdraw(sdp, sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks);
 	gfs2_log_unlock(sdp);
 
@@ -504,7 +567,7 @@ static void log_write_header(struct gfs2_sbd *sdp, u32 flags, int pull)
 	brelse(bh);
 
 	if (sdp->sd_log_tail != tail)
-		log_pull_tail(sdp, tail, pull);
+		log_pull_tail(sdp, tail);
 	else
 		gfs2_assert_withdraw(sdp, !pull);
 
@@ -517,6 +580,7 @@ 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;
+	int flushcount = 0;
 
 	while (!list_empty(head)) {
 		lb = list_entry(head->next, struct gfs2_log_buf, lb_list);
@@ -533,9 +597,20 @@ static void log_flush_commit(struct gfs2_sbd *sdp)
 		} else
 			brelse(bh);
 		kfree(lb);
+		flushcount++;
 	}
 
-	log_write_header(sdp, 0, 0);
+	/* If nothing was journaled, the header is unplanned and unwanted. */
+	if (flushcount) {
+		log_write_header(sdp, 0, 0);
+	} else {
+		unsigned int tail;
+		tail = current_tail(sdp);
+
+		gfs2_ail1_empty(sdp, 0);
+		if (sdp->sd_log_tail != tail)
+			log_pull_tail(sdp, tail);
+	}
 }
 
 /**
@@ -565,7 +640,10 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
 	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_buf + sdp->sd_log_num_jdata ==
+			     sdp->sd_log_commited_buf +
+			     sdp->sd_log_commited_databuf);
 	gfs2_assert_withdraw(sdp,
 			sdp->sd_log_num_revoke == sdp->sd_log_commited_revoke);
 
@@ -576,16 +654,19 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
 	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)
+	else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle){
+		gfs2_log_lock(sdp);
+		sdp->sd_log_blks_free--; /* Adjust for unreserved buffer */
+		gfs2_log_unlock(sdp);
 		log_write_header(sdp, 0, PULL);
+	}
 	lops_after_commit(sdp, ai);
 
 	gfs2_log_lock(sdp);
 	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_databuf = 0;
 	sdp->sd_log_commited_revoke = 0;
 
 	if (!list_empty(&ai->ai_ail1_list)) {
@@ -602,32 +683,26 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
 
 static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 {
-	unsigned int reserved = 0;
+	unsigned int reserved;
 	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_databuf += tr->tr_num_databuf_new -
+		tr->tr_num_databuf_rm;
+	gfs2_assert_withdraw(sdp, (((int)sdp->sd_log_commited_buf) >= 0) ||
+			     (((int)sdp->sd_log_commited_databuf) >= 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++;
-
+	reserved = calc_reserved(sdp);
 	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);
+	gfs2_assert_withdraw(sdp, sdp->sd_log_blks_free <=
+			     sdp->sd_jdesc->jd_blocks);
 
 	sdp->sd_log_blks_reserved = reserved;
 
@@ -673,13 +748,13 @@ void gfs2_log_shutdown(struct gfs2_sbd *sdp)
 	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);
+	log_write_header(sdp, GFS2_LOG_HEAD_UNMOUNT,
+			 (sdp->sd_log_tail == current_tail(sdp)) ? 0 : PULL);
 
 	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);