From: NeilBrown <neilb@suse.de>
Date: Wed, 15 Sep 2010 02:57:07 +0000 (+1000)
Subject: Take a ref on dblock whenever the InoIdx block has a ->parent link.
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=acdf79893018ffffc902990732b86d37fc658dbb;p=LaFS.git

Take a ref on dblock whenever the InoIdx block has a ->parent link.

This will be needed to ensure the dblock stays referenced when we stop
holding a reference to blocks on the 'leafs' lists.

Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/index.c b/index.c
index 1f7759b..acff2fe 100644
--- a/index.c
+++ b/index.c
@@ -366,8 +366,16 @@ block_adopt(struct block *blk, struct indexblock *parent)
 		/* Remove from the per-inode free list */
 		if (!test_bit(B_InoIdx, &blk->flags))
 			list_move(&blk->siblings, &parent->children);
-		else
+		else {
+			/* Remove from ->free_index list */
 			list_del_init(&blk->siblings);
+			/* Having set ->parent, we take a ref on the dblock.
+			 * The dblock must exist because we can only reach here from
+			 * lafs_make_iblock which can only be called while holding a ref
+			 * on the dblock
+			 */
+			(void)getdref(LAFSI(blk->inode)->dblock, MKREF(pdblock));
+		}
 	}
 	spin_unlock(&as->private_lock);
 }
@@ -973,6 +981,26 @@ void lafs_refile(struct block *b, int dec)
 				del_ref(&b->parent->b, MKREF(child),
 					__FILE__, __LINE__);
 				b->parent = NULL;
+
+				if (test_bit(B_InoIdx, &b->flags)) {
+					/* While an InoIdx has a parent we hold a count on
+					 * the dblock.  Now we have dropped one, we must drop the
+					 * other
+					 */
+					struct datablock *db = LAFSI(b->inode)->dblock;
+					if (&db->b.parent->b != next_parent &&
+					    &db->b != next_parent) {
+						printk("db    = %s\n", strblk(&db->b));
+						printk("dp->p = %s\n", strblk(&db->b.parent->b));
+						printk("np    = %s\n", strblk(next_parent));
+						printk("b     = %s\n", strblk(b));
+					}
+					BUG_ON(&db->b.parent->b != next_parent && &db->b != next_parent);
+					if (atomic_dec_and_test(&next_parent->refcnt))
+						LAFS_BUG(1, b);
+					next_parent = &db->b;
+					del_ref(&db->b, MKREF(pdblock), __FILE__, __LINE__);
+				}
 				if (test_and_clear_bit(B_SegRef, &b->flags))
 					physref = b->physaddr;
 				spin_lock(&b->inode->i_data.private_lock);