From bd83396c88258526ce5a99fb7f41a233ef68e45f Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Fri, 15 Oct 2010 15:05:37 +1100
Subject: [PATCH] roll-forward: don't iput any nlink==0 inode before
 roll-forward finishes.

Such inodes might still need to participate in roll-forward, and might
yet get linked into the directory tree.  So don't risk them being
deleted yet.
So any inode with nlink==0 is put on the list to be dealt with at the
end.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 inode.c |  6 +++++-
 roll.c  | 45 +++++++++++++++++++++++++++++++++------------
 2 files changed, 38 insertions(+), 13 deletions(-)

diff --git a/inode.c b/inode.c
index 759365c..05c7350 100644
--- a/inode.c
+++ b/inode.c
@@ -393,7 +393,8 @@ lafs_import_inode(struct inode *ino, struct datablock *b)
 		ino->i_size = le64_to_cpu(l->size);
 		i->parent = le32_to_cpu(l->parent);
 		ino->i_nlink = le32_to_cpu(l->linkcount);
-		if (ino->i_nlink == 0 && list_empty(&b->orphans)) {
+		if (ino->i_nlink == 0 && list_empty(&b->orphans) &&
+		    fs_from_inode(ino)->rolled) {
 			/* This block should already be on the orphan
 			 * list, otherwise there is a filesystem
 			 * inconsistency.
@@ -401,6 +402,9 @@ lafs_import_inode(struct inode *ino, struct datablock *b)
 			 * linkcount is wrong.
 			 * It is safest to assume the later - either
 			 * way an FS check would be needed to fix it.
+			 * Note: while roll-forward is happening, this
+			 * situation is perfectly possible and is handled
+			 * correctly.
 			 */
 			/* FIXME set a superblock flag requesting
 			 * directory linkage checking
diff --git a/roll.c b/roll.c
index ca81735..01d891e 100644
--- a/roll.c
+++ b/roll.c
@@ -236,7 +236,7 @@ roll_mini(struct fs *fs, int fsnum, int inum, int trunc,
 {
 	struct inode *inode;
 	struct lafs_inode *li;
-	struct datablock *db;
+	struct datablock *db = NULL;
 	int err = 0;
 	void *buf;
 
@@ -291,23 +291,17 @@ roll_mini(struct fs *fs, int fsnum, int inum, int trunc,
 			err = PTR_ERR(db);
 			break;
 		}
+		/* Should normally iolock the block, but we don't
+		 * need that during roll-forward */
+		set_bit(B_PinPending, &db->b.flags);
+		lafs_pin_dblock(db, CleanSpace);
 		/* Make sure block is in-sync with inode */
 		lafs_inode_fillblock(inode);
 		buf = map_dblock(db);
 		memcpy(buf+offset, data, len);
 		unmap_dblock(db, buf);
 		err = lafs_import_inode(inode, db);
-		/* We borrow the orphan list to keep a reference on
-		 * this inode until all processing is finished
-		 * to make sure inodes that are about to get linked
-		 * to get deleted early
-		 */
-		if (list_empty(&db->orphans)) {
-			list_add(&db->orphans, &fs->pending_orphans);
-			lafs_igrab_fs(inode);
-			getdref(db, MKREF(roll_orphan));
-		}
-		putdref(db, MKREF(roll));
+		lafs_dirty_dblock(db);
 		break;
 
 	case TypeDir:
@@ -315,6 +309,22 @@ roll_mini(struct fs *fs, int fsnum, int inum, int trunc,
 		BUG();
 		break;
 	}
+	/* We borrow the orphan list to keep a reference on
+	 * this inode until all processing is finished
+	 * to make sure inodes that are about to get linked
+	 * don't get deleted early
+	 */
+	if (inode->i_nlink == 0) {
+		if (!db)
+			db = lafs_inode_get_dblock(inode, MKREF(roll));
+		if (db &&
+		    list_empty(&db->orphans)) {
+			list_add(&db->orphans, &fs->pending_orphans);
+			lafs_igrab_fs(inode);
+			getdref(db, MKREF(roll_orphan));
+		}
+	}
+	putdref(db, MKREF(roll));
 	lafs_iput_fs(inode);
 	return err;
 }
@@ -445,6 +455,17 @@ roll_block(struct fs *fs, int fsnum, int inum, int trunc,
 	}
 	if (blk)
 		putdref(blk, MKREF(roll));
+
+	if (inode->i_nlink == 0) {
+		struct datablock *db = lafs_inode_get_dblock(inode, MKREF(roll));
+		if (db &&
+		    list_empty(&db->orphans)) {
+			list_add(&db->orphans, &fs->pending_orphans);
+			lafs_igrab_fs(inode);
+			getdref(db, MKREF(roll_orphan));
+		}
+		putdref(db, MKREF(roll));
+	}
 	lafs_iput_fs(inode);
 	dprintk("leaving with error %d\n", err);
 	return err;
-- 
2.43.0