From: NeilBrown <neilb@suse.de>
Date: Sat, 2 Oct 2010 11:15:39 +0000 (+1000)
Subject: Be more robust in face of read errors on orphan list.
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=6f1426b4a5dcc40dd960f2eac2b4558d80203633;p=LaFS.git

Be more robust in face of read errors on orphan list.

This isn't *very* robust, but we shouldn't BUG now.  Worst case
is we loose some orphans and some orphan slots.  fsck will have
to deal with that.

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

diff --git a/orphan.c b/orphan.c
index 7dbb720..5064820 100644
--- a/orphan.c
+++ b/orphan.c
@@ -354,7 +354,7 @@ void lafs_orphan_release(struct fs *fs, struct datablock *b, struct inode *ino)
 
 	dprintk("os=%d sh=%d ent=%d nf=%d\n", b->orphan_slot, shift,
 		ent, om->nextfree);
-
+again:
 	if (b->orphan_slot != om->nextfree-1) {
 		/* need to swap in the last entry */
 		struct inode *bino;
@@ -382,6 +382,17 @@ void lafs_orphan_release(struct fs *fs, struct datablock *b, struct inode *ino)
 		lastor[lastent].type = 0;
 		unmap_dblock_2(ob2, lastor);
 
+		if (last.type == 0) {
+			/* this entry was invalidated during read-in.
+			 * lets just forget it
+			 */
+			om->nextfree--;
+			om->reserved++;
+			orphan_abort(fs);
+			putdref(ob2, MKREF(orphan_move));
+			goto again;
+		}
+
 		/* The block, being an orphan, must exist */
 		bino = lafs_iget_fs(fs,
 				    le32_to_cpu(last.filesys),
@@ -626,7 +637,9 @@ int lafs_count_orphans(struct inode *ino)
 	/* Count how many active orphan slots there are
 	 * in this file (which is the orphan file).
 	 * We simply iterate all the slots until we
-	 * find an empty one
+	 * find an empty one.
+	 * We keep references to the blocks so lafs_add_orphans
+	 * is certain to find them.
 	 */
 	int bnum = -1;
 	int slots = 1 << (ino->i_blkbits - 4);
@@ -653,7 +666,8 @@ int lafs_count_orphans(struct inode *ino)
 				break;
 
 		unmap_dblock(db, or);
-		putdref(db, MKREF(count_orphans));
+		if (slot == 0)
+			putdref(db, MKREF(count_orphans));
 	} while (slot == slots);
 
 	return bnum * slots + slot;
@@ -671,28 +685,26 @@ void lafs_add_orphans(struct fs *fs, struct inode *ino, int count)
 		struct orphan *or;
 		int slot;
 
-		if (!db)
-			continue;
-
-		if (lafs_read_block(db) < 0) {
-			putdref(db, MKREF(add_orphans));
-			continue;
-		}
+		/* We already own a count_orphans ref on this block */
+		BUG_ON(!db);
+		LAFS_BUG(!test_bit(B_Valid, &db->b.flags), &db->b);
+		putdref(db, MKREF(count_orphans));
 
 		or = map_dblock(db);
 		for (slot = 0; slot < slots && bslot + slot < count; slot++) {
 			struct inode *oino;
 			struct datablock *ob;
 
-			if (or[slot].type == 0)
-				continue;
+			LAFS_BUG(or[slot].type == 0, &db->b);
 			
 			oino = lafs_iget_fs(fs,
 					    le32_to_cpu(or[slot].filesys),
 					    le32_to_cpu(or[slot].inum),
 					    SYNC);
-			if (IS_ERR(oino))
+			if (IS_ERR(oino)) {
+				or[slot].type = 0;
 				continue;
+			}
 
 			ob = lafs_get_block(oino, le32_to_cpu(or[slot].addr), NULL,
 					    GFP_KERNEL, MKREF(add_orphan));
@@ -703,7 +715,8 @@ void lafs_add_orphans(struct fs *fs, struct inode *ino, int count)
 					getdref(db, MKREF(orphan));
 					ob->orphan_slot = bslot + slot;
 					lafs_add_orphan(fs, ob);
-				}
+				} else
+					or[slot].type = 0;
 				putdref(ob, MKREF(add_orphan));
 			}
 			iput(oino);