[Cluster-devel] [GFS2 PATCH 10/15] GFS2: Change from tr_touched to tr_bufs

[Bob Peterson <rpeterso@redhat.com>]

This patch changes the GFS2 transaction processing so that it keeps
track of how many buffers are associated with a transaction rather
than whether or not it's been touched. That way, if a buffer is
added, then revoked, then removed entirely, it can avoid some work.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
---
 fs/gfs2/incore.h  |  5 ++++-
 fs/gfs2/meta_io.c |  6 +++---
 fs/gfs2/trans.c   | 13 +++++++------
 3 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 5065e0c..c8f9bb9 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -473,10 +473,13 @@ struct gfs2_trans {
 	unsigned int tr_blocks;
 	unsigned int tr_revokes;
 	unsigned int tr_reserved;
-	unsigned int tr_touched:1;
 	unsigned int tr_attached:1;
 	unsigned int tr_alloced:1;
 
+	struct gfs2_holder tr_t_gh;
+
+	int tr_bufs;
+
 	unsigned int tr_num_buf_new;
 	unsigned int tr_num_databuf_new;
 	unsigned int tr_num_buf_rm;
diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
index 0e1d4be..c20d7ca 100644
--- a/fs/gfs2/meta_io.c
+++ b/fs/gfs2/meta_io.c
@@ -224,7 +224,7 @@ int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
 	wait_on_buffer(bh);
 	if (unlikely(!buffer_uptodate(bh))) {
 		struct gfs2_trans *tr = current->journal_info;
-		if (tr && tr->tr_touched)
+		if (tr && tr->tr_bufs)
 			gfs2_io_error_bh(sdp, bh);
 		brelse(bh);
 		*bhp = NULL;
@@ -251,7 +251,7 @@ int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
 
 	if (!buffer_uptodate(bh)) {
 		struct gfs2_trans *tr = current->journal_info;
-		if (tr && tr->tr_touched)
+		if (tr && tr->tr_bufs)
 			gfs2_io_error_bh(sdp, bh);
 		return -EIO;
 	}
@@ -276,7 +276,7 @@ void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int
 			tr->tr_num_buf_rm++;
 		else
 			tr->tr_num_databuf_rm++;
-		tr->tr_touched = 1;
+		tr->tr_bufs--;
 		was_pinned = 1;
 		brelse(bh);
 	}
diff --git a/fs/gfs2/trans.c b/fs/gfs2/trans.c
index b95d0d6..6ff5faa 100644
--- a/fs/gfs2/trans.c
+++ b/fs/gfs2/trans.c
@@ -77,8 +77,8 @@ fail:
 static void gfs2_print_trans(const struct gfs2_trans *tr)
 {
 	pr_warn("Transaction created at: %pSR\n", (void *)tr->tr_ip);
-	pr_warn("blocks=%u revokes=%u reserved=%u touched=%u\n",
-		tr->tr_blocks, tr->tr_revokes, tr->tr_reserved, tr->tr_touched);
+	pr_warn("blocks=%u revokes=%u reserved=%u bufs=%d\n",
+		tr->tr_blocks, tr->tr_revokes, tr->tr_reserved, tr->tr_bufs);
 	pr_warn("Buf %u/%u Databuf %u/%u Revoke %u/%u\n",
 		tr->tr_num_buf_new, tr->tr_num_buf_rm,
 		tr->tr_num_databuf_new, tr->tr_num_databuf_rm,
@@ -94,7 +94,7 @@ void gfs2_trans_end(struct gfs2_sbd *sdp)
 	BUG_ON(!tr);
 	current->journal_info = NULL;
 
-	if (!tr->tr_touched) {
+	if (tr->tr_bufs == 0) {
 		gfs2_log_release(sdp, tr->tr_reserved);
 		if (alloced) {
 			kfree(tr);
@@ -180,7 +180,7 @@ void gfs2_trans_add_data(struct gfs2_glock *gl, struct buffer_head *bh)
 		gfs2_log_lock(sdp);
 	}
 	gfs2_assert(sdp, bd->bd_gl == gl);
-	tr->tr_touched = 1;
+	tr->tr_bufs++;
 	if (list_empty(&bd->bd_list)) {
 		set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
 		set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
@@ -199,7 +199,7 @@ static void meta_lo_add(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
 	enum gfs2_freeze_state state = atomic_read(&sdp->sd_freeze_state);
 
 	tr = current->journal_info;
-	tr->tr_touched = 1;
+	tr->tr_bufs++;
 	if (!list_empty(&bd->bd_list))
 		return;
 	set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
@@ -252,7 +252,7 @@ void gfs2_trans_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
 
 	BUG_ON(!list_empty(&bd->bd_list));
 	gfs2_add_revoke(sdp, bd);
-	tr->tr_touched = 1;
+	tr->tr_bufs++;
 	tr->tr_num_revoke++;
 }
 
@@ -268,6 +268,7 @@ void gfs2_trans_add_unrevoke(struct gfs2_sbd *sdp, u64 blkno, unsigned int len)
 			list_del_init(&bd->bd_list);
 			gfs2_assert_withdraw(sdp, sdp->sd_log_num_revoke);
 			sdp->sd_log_num_revoke--;
+			tr->tr_bufs--;
 			kmem_cache_free(gfs2_bufdata_cachep, bd);
 			tr->tr_num_revoke_rm++;
 			if (--n == 0)
-- 
2.4.3