GFS2: replace gfs2_ail structure with gfs2_trans

In order to allow transactions and log flushes to happen at the same
time, gfs2 needs to move the transaction accounting and active items
list code into the gfs2_trans structure.  As a first step toward this,
this patch removes the gfs2_ail structure, and handles the active items
list in the gfs_trans structure.  This keeps gfs2 from allocating an ail
structure on log flushes, and gives us a struture that can later be used
to store the transaction accounting outside of the gfs2 superblock
structure.

With this patch, at the end of a transaction, gfs2 will add the
gfs2_trans structure to the superblock if there is not one already.
This structure now has the active items fields that were previously in
gfs2_ail.  This is not necessary in the case where the transaction was
simply used to add revokes, since these are never written outside of the
journal, and thus, don't need an active items list.

Also, in order to make sure that the transaction structure is not
removed while it's still in use by gfs2_trans_end, unlocking the
sd_log_flush_lock has to happen slightly later in ending the
transaction.

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

1 files changed, 21 insertions, 11 deletions

diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
index a505597..7318abf 100644
--- a/fs/gfs2/lops.c
+++ b/fs/gfs2/lops.c
@@ -53,8 +53,8 @@ void gfs2_pin(struct gfs2_sbd *sdp, struct buffer_head *bh)
 	 * to in-place disk block, remove it from the AIL.
 	 */
 	spin_lock(&sdp->sd_ail_lock);
-	if (bd->bd_ail)
-		list_move(&bd->bd_ail_st_list, &bd->bd_ail->ai_ail2_list);
+	if (bd->bd_tr)
+		list_move(&bd->bd_ail_st_list, &bd->bd_tr->tr_ail2_list);
 	spin_unlock(&sdp->sd_ail_lock);
 	get_bh(bh);
 	atomic_inc(&sdp->sd_log_pinned);
@@ -94,7 +94,7 @@ static void maybe_release_space(struct gfs2_bufdata *bd)
  */
 
 static void gfs2_unpin(struct gfs2_sbd *sdp, struct buffer_head *bh,
-		       struct gfs2_ail *ai)
+		       struct gfs2_trans *tr)
 {
 	struct gfs2_bufdata *bd = bh->b_private;
 
@@ -109,7 +109,7 @@ static void gfs2_unpin(struct gfs2_sbd *sdp, struct buffer_head *bh,
 		maybe_release_space(bd);
 
 	spin_lock(&sdp->sd_ail_lock);
-	if (bd->bd_ail) {
+	if (bd->bd_tr) {
 		list_del(&bd->bd_ail_st_list);
 		brelse(bh);
 	} else {
@@ -117,8 +117,8 @@ static void gfs2_unpin(struct gfs2_sbd *sdp, struct buffer_head *bh,
 		list_add(&bd->bd_ail_gl_list, &gl->gl_ail_list);
 		atomic_inc(&gl->gl_ail_count);
 	}
-	bd->bd_ail = ai;
-	list_add(&bd->bd_ail_st_list, &ai->ai_ail1_list);
+	bd->bd_tr = tr;
+	list_add(&bd->bd_ail_st_list, &tr->tr_ail1_list);
 	spin_unlock(&sdp->sd_ail_lock);
 
 	clear_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
@@ -480,17 +480,22 @@ static void buf_lo_before_commit(struct gfs2_sbd *sdp)
 			   &sdp->sd_log_le_buf, 0);
 }
 
-static void buf_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
+static void buf_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 {
 	struct list_head *head = &sdp->sd_log_le_buf;
 	struct gfs2_bufdata *bd;
 
+	if (tr == NULL) {
+		gfs2_assert(sdp, list_empty(head));
+		return;
+	}
+
 	while (!list_empty(head)) {
 		bd = list_entry(head->next, struct gfs2_bufdata, bd_list);
 		list_del_init(&bd->bd_list);
 		sdp->sd_log_num_buf--;
 
-		gfs2_unpin(sdp, bd->bd_bh, ai);
+		gfs2_unpin(sdp, bd->bd_bh, tr);
 	}
 	gfs2_assert_warn(sdp, !sdp->sd_log_num_buf);
 }
@@ -613,7 +618,7 @@ static void revoke_lo_before_commit(struct gfs2_sbd *sdp)
 	gfs2_log_write_page(sdp, page);
 }
 
-static void revoke_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
+static void revoke_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 {
 	struct list_head *head = &sdp->sd_log_le_revoke;
 	struct gfs2_bufdata *bd;
@@ -791,16 +796,21 @@ static void databuf_lo_after_scan(struct gfs2_jdesc *jd, int error, int pass)
 		jd->jd_jid, sdp->sd_replayed_blocks, sdp->sd_found_blocks);
 }
 
-static void databuf_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_ail *ai)
+static void databuf_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 {
 	struct list_head *head = &sdp->sd_log_le_databuf;
 	struct gfs2_bufdata *bd;
 
+	if (tr == NULL) {
+		gfs2_assert(sdp, list_empty(head));
+		return;
+	}
+
 	while (!list_empty(head)) {
 		bd = list_entry(head->next, struct gfs2_bufdata, bd_list);
 		list_del_init(&bd->bd_list);
 		sdp->sd_log_num_databuf--;
-		gfs2_unpin(sdp, bd->bd_bh, ai);
+		gfs2_unpin(sdp, bd->bd_bh, tr);
 	}
 	gfs2_assert_warn(sdp, !sdp->sd_log_num_databuf);
 }