protocol/server: forget the inodes which got ENOENT in lookup

                 Backport of http://review.gluster.org/11489

If a looked up object is removed from the backend, then upon getting a
revalidated lookup on that object ENOENT error is received. protocol/server
xlator handles it by removing dentry upon which ENOENT is received. But the
inode associated with it still remains in the inode table, and whoever does
nameless lookup on the gfid of that object will be able to do it successfully
despite the object being not present.

For handling this issue, upon getting ENOENT on a looked up entry in revalidate
lookups, protocol/server should forget the inode as well.

Though removing files directly from the backend is not allowed, in case of
objects corrupted due to bitrot and marked as bad by scrubber, objects are
removed directly from the backend in case of replicate volumes, so that the
object is healed from the good copy. For handling this, the inode of the bad
object removed from the backend should be forgotten. Otherwise, the inode which
knows the object it represents is bad, does not allow read/write operations
happening as part of self-heal.

Change-Id: I268eeaf37969458687425187be6622347a6cc1f1
BUG: 1255604
Signed-off-by: Raghavendra Bhat <raghavendra@redhat.com>
Reviewed-on: http://review.gluster.org/11973
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Raghavendra G <rgowdapp@redhat.com>

2 files changed, 29 insertions, 0 deletions

diff --git a/libglusterfs/src/inode.c b/libglusterfs/src/inode.c
index 70150536643..7f717535f39 100644
--- a/libglusterfs/src/inode.c
+++ b/libglusterfs/src/inode.c
@@ -1319,6 +1319,32 @@ inode_parent (inode_t *inode, uuid_t pargfid, const char *name)
         return parent;
 }
 
+static int
+__inode_has_dentry (inode_t *inode)
+{
+        if (!inode) {
+                gf_msg_callingfn (THIS->name, GF_LOG_WARNING, 0,
+                                  LG_MSG_INODE_NOT_FOUND, "inode not found");
+                return 0;
+        }
+
+        return !list_empty (&inode->dentry_list);
+}
+
+int
+inode_has_dentry (inode_t *inode)
+{
+
+        int dentry_present = 0;
+
+        LOCK (&inode->lock);
+        {
+                dentry_present = __inode_has_dentry (inode);
+        }
+        UNLOCK (&inode->lock);
+
+        return dentry_present;
+}
 
 int
 __inode_path (inode_t *inode, const char *name, char **bufp)
diff --git a/libglusterfs/src/inode.h b/libglusterfs/src/inode.h
index b8bac7932c3..a17970e8174 100644
--- a/libglusterfs/src/inode.h
+++ b/libglusterfs/src/inode.h
@@ -278,4 +278,7 @@ inode_set_need_lookup (inode_t *inode, xlator_t *this);
 gf_boolean_t
 inode_needs_lookup (inode_t *inode, xlator_t *this);
 
+int
+inode_has_dentry (inode_t *inode);
+
 #endif /* _INODE_H */