GFS2: Move log buffer accounting to transaction

Now we have a master transaction into which other transactions
are merged, the accounting can be done using this master
transaction. We no longer require the superblock fields which
were being used for this function.

In addition, this allows for a clean up in calc_reserved()
making it rather easier understand. Also, by reducing the
number of variables used to track the buffers being added
and removed from the journal, a number of error checks are
now no longer required.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 24 insertions, 43 deletions

diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 975712c..c1c9a29 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -414,24 +414,22 @@ static inline unsigned int log_distance(struct gfs2_sbd *sdp, unsigned int newer
 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;
+	unsigned int mbuf;
+	unsigned int dbuf;
+	struct gfs2_trans *tr = sdp->sd_log_tr;
 
-	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 (tr) {
+		mbuf = tr->tr_num_buf_new - tr->tr_num_buf_rm;
+		dbuf = tr->tr_num_databuf_new - tr->tr_num_databuf_rm;
+		reserved = mbuf + dbuf;
+		/* Account for header blocks */
+		reserved += DIV_ROUND_UP(mbuf, buf_limit(sdp));
+		reserved += DIV_ROUND_UP(dbuf, databuf_limit(sdp));
+	}
 
 	if (sdp->sd_log_commited_revoke > 0)
-		revokes = gfs2_struct2blk(sdp, sdp->sd_log_commited_revoke,
+		reserved += 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++;
@@ -693,16 +691,6 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
 		INIT_LIST_HEAD(&tr->tr_ail2_list);
 	}
 
-	if (sdp->sd_log_num_buf != sdp->sd_log_commited_buf) {
-		printk(KERN_INFO "GFS2: log buf %u %u\n", sdp->sd_log_num_buf,
-		       sdp->sd_log_commited_buf);
-		gfs2_assert_withdraw(sdp, 0);
-	}
-	if (sdp->sd_log_num_databuf != sdp->sd_log_commited_databuf) {
-		printk(KERN_INFO "GFS2: log databuf %u %u\n",
-		       sdp->sd_log_num_databuf, sdp->sd_log_commited_databuf);
-		gfs2_assert_withdraw(sdp, 0);
-	}
 	gfs2_assert_withdraw(sdp,
 			sdp->sd_log_num_revoke == sdp->sd_log_commited_revoke);
 
@@ -727,8 +715,6 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
 	gfs2_log_lock(sdp);
 	sdp->sd_log_head = sdp->sd_log_flush_head;
 	sdp->sd_log_blks_reserved = 0;
-	sdp->sd_log_commited_buf = 0;
-	sdp->sd_log_commited_databuf = 0;
 	sdp->sd_log_commited_revoke = 0;
 
 	spin_lock(&sdp->sd_ail_lock);
@@ -769,31 +755,29 @@ static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 {
 	unsigned int reserved;
 	unsigned int unused;
+	unsigned int maxres;
 
 	gfs2_log_lock(sdp);
 
-	sdp->sd_log_commited_buf += tr->tr_num_buf_new - tr->tr_num_buf_rm;
-	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));
+	if (sdp->sd_log_tr) {
+		gfs2_merge_trans(sdp->sd_log_tr, tr);
+	} else if (tr->tr_num_buf_new || tr->tr_num_databuf_new) {
+		gfs2_assert_withdraw(sdp, tr->tr_t_gh.gh_gl);
+		sdp->sd_log_tr = tr;
+		tr->tr_attached = 1;
+	}
+
 	sdp->sd_log_commited_revoke += tr->tr_num_revoke - tr->tr_num_revoke_rm;
 	reserved = calc_reserved(sdp);
-	gfs2_assert_withdraw(sdp, sdp->sd_log_blks_reserved + tr->tr_reserved >= reserved);
-	unused = sdp->sd_log_blks_reserved - reserved + tr->tr_reserved;
+	maxres = sdp->sd_log_blks_reserved + tr->tr_reserved;
+	gfs2_assert_withdraw(sdp, maxres >= reserved);
+	unused = maxres - reserved;
 	atomic_add(unused, &sdp->sd_log_blks_free);
 	trace_gfs2_log_blocks(sdp, unused);
 	gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
 			     sdp->sd_jdesc->jd_blocks);
 	sdp->sd_log_blks_reserved = reserved;
 
-	if (sdp->sd_log_tr) {
-		gfs2_merge_trans(sdp->sd_log_tr, tr);
-	} else if (tr->tr_num_buf_new || tr->tr_num_databuf_new) {
-		gfs2_assert_withdraw(sdp, tr->tr_t_gh.gh_gl);
-		sdp->sd_log_tr = tr;
-		tr->tr_attached = 1;
-	}
 	gfs2_log_unlock(sdp);
 }
 
@@ -833,10 +817,7 @@ 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_buf);
 	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, list_empty(&sdp->sd_ail1_list));
 
 	sdp->sd_log_flush_head = sdp->sd_log_head;