[Cluster-devel] [PATCH 51/66] fsck.gfs2: system dinodes take priority over user dinodes

[rpeterso at redhat.com]

From: Bob Peterson <rpeterso at redhat.com>

In testing fsck.gfs2 I noticed some incorrect behavior: If a block
was referenced incorrectly by two dinodes, fsck deleted which
ever reference it found first.  Therefore, if a system dinode
and a user dinode referenced the same block, fsck.gfs2 could
mistakenly delete the system dinode.  For example, a journal could
get deleted because a user dinode improperly referenced one of its
blocks.  This patch gives priority to system dinodes when resolving
duplicates.

rhbz#675723
---
 gfs2/fsck/pass1b.c |    9 ++++++++-
 gfs2/fsck/util.c   |   14 ++++++++++++--
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/gfs2/fsck/pass1b.c b/gfs2/fsck/pass1b.c
index b7be683..da71f99 100644
--- a/gfs2/fsck/pass1b.c
+++ b/gfs2/fsck/pass1b.c
@@ -483,7 +483,14 @@ static int resolve_dup_references(struct gfs2_sbd *sdp, struct duptree *b,
 				continue; /* don't delete the dinode */
 			}
 		}
-
+		/* If this reference is from a system inode, for example, if
+		   it's data or metadata inside a journal, the reference
+		   should take priority over user dinodes that reference the
+		   block. */
+		if (!found_good_ref && fsck_system_inode(sdp, id->block_no)) {
+			found_good_ref = 1;
+			continue; /* don't delete the dinode */
+		}
 		log_warn( _("Inode %s (%lld/0x%llx) references block "
 			    "%llu (0x%llx) as '%s', but the block is "
 			    "really %s.\n"),
diff --git a/gfs2/fsck/util.c b/gfs2/fsck/util.c
index 69bf328..0be86de 100644
--- a/gfs2/fsck/util.c
+++ b/gfs2/fsck/util.c
@@ -280,8 +280,18 @@ int add_duplicate_ref(struct gfs2_inode *ip, uint64_t block,
 		   inode reference list otherwise put it on the normal list. */
 		if (!inode_valid || q == gfs2_inode_invalid)
 			osi_list_add_prev(&id->list, &dt->ref_invinode_list);
-		else
-			osi_list_add_prev(&id->list, &dt->ref_inode_list);
+		else {
+			/* If this is a system dinode, we want the duplicate
+			   processing to find it first. That way references
+			   from inside journals, et al, will take priority.
+			   We don't want to delete journals in favor of dinodes
+			   that reference a block inside a journal. */
+			if (fsck_system_inode(ip->i_sbd, id->block_no))
+				osi_list_add(&id->list, &dt->ref_inode_list);
+			else
+				osi_list_add_prev(&id->list,
+						  &dt->ref_inode_list);
+		}
 	}
 	id->reftypecount[reftype]++;
 	id->dup_count++;
-- 
1.7.7.5