GFS2: Fix error path in gfs2_lookup_by_inum()

In the (impossible, except if there is fs corruption) error path
in gfs2_lookup_by_inum() if the call to gfs2_inode_refresh()
fails, it was leaving the function by calling iput() rather
than iget_failed(). This would cause future lookups of the same
inode to block forever.

This patch fixes the problem by moving the call to gfs2_inode_refresh()
into gfs2_inode_lookup() where iget_failed() is part of the error path
already. Also this cleans up some unreachable code and makes
gfs2_set_iop() static.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

fs/gfs2/inode.c

@@ -74,16 +74,14 @@ static struct inode *gfs2_iget(struct super_block *sb, u64 no_addr)
 }
 
 /**
- * GFS2 lookup code fills in vfs inode contents based on info obtained
- * from directory entry inside gfs2_inode_lookup(). This has caused issues
- * with NFS code path since its get_dentry routine doesn't have the relevant
- * directory entry when gfs2_inode_lookup() is invoked. Part of the code
- * segment inside gfs2_inode_lookup code needs to get moved around.
+ * gfs2_set_iop - Sets inode operations
+ * @inode: The inode with correct i_mode filled in
  *
- * Clears I_NEW as well.
- **/
+ * GFS2 lookup code fills in vfs inode contents based on info obtained
+ * from directory entry inside gfs2_inode_lookup().
+ */
 
-void gfs2_set_iop(struct inode *inode)
+static void gfs2_set_iop(struct inode *inode)
 {
 	struct gfs2_sbd *sdp = GFS2_SB(inode);
 	umode_t mode = inode->i_mode;
@@ -106,8 +104,6 @@ void gfs2_set_iop(struct inode *inode)
 		inode->i_op = &gfs2_file_iops;
 		init_special_inode(inode, inode->i_mode, inode->i_rdev);
 	}
-
-	unlock_new_inode(inode);
 }
 
 /**
@@ -119,10 +115,8 @@ void gfs2_set_iop(struct inode *inode)
  * Returns: A VFS inode, or an error
  */
 
-struct inode *gfs2_inode_lookup(struct super_block *sb,
-				unsigned int type,
-				u64 no_addr,
-				u64 no_formal_ino)
+struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned int type,
+				u64 no_addr, u64 no_formal_ino)
 {
 	struct inode *inode;
 	struct gfs2_inode *ip;
@@ -152,51 +146,37 @@ struct inode *gfs2_inode_lookup(struct super_block *sb,
 		error = gfs2_glock_nq_init(io_gl, LM_ST_SHARED, GL_EXACT, &ip->i_iopen_gh);
 		if (unlikely(error))
 			goto fail_iopen;
-		ip->i_iopen_gh.gh_gl->gl_object = ip;
 
+		ip->i_iopen_gh.gh_gl->gl_object = ip;
 		gfs2_glock_put(io_gl);
 		io_gl = NULL;
 
-		if ((type == DT_UNKNOWN) && (no_formal_ino == 0))
-			goto gfs2_nfsbypass;
-
-		inode->i_mode = DT2IF(type);
-
-		/*
-		 * We must read the inode in order to work out its type in
-		 * this case. Note that this doesn't happen often as we normally
-		 * know the type beforehand. This code path only occurs during
-		 * unlinked inode recovery (where it is safe to do this glock,
-		 * which is not true in the general case).
-		 */
 		if (type == DT_UNKNOWN) {
-			struct gfs2_holder gh;
-			error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
-			if (unlikely(error))
-				goto fail_glock;
-			/* Inode is now uptodate */
-			gfs2_glock_dq_uninit(&gh);
+			/* Inode glock must be locked already */
+			error = gfs2_inode_refresh(GFS2_I(inode));
+			if (error)
+				goto fail_refresh;
+		} else {
+			inode->i_mode = DT2IF(type);
 		}
 
 		gfs2_set_iop(inode);
+		unlock_new_inode(inode);
 	}
 
-gfs2_nfsbypass:
 	return inode;
-fail_glock:
-	gfs2_glock_dq(&ip->i_iopen_gh);
+
+fail_refresh:
+	ip->i_iopen_gh.gh_gl->gl_object = NULL;
+	gfs2_glock_dq_uninit(&ip->i_iopen_gh);
 fail_iopen:
 	if (io_gl)
 		gfs2_glock_put(io_gl);
 fail_put:
-	if (inode->i_state & I_NEW)
-		ip->i_gl->gl_object = NULL;
+	ip->i_gl->gl_object = NULL;
 	gfs2_glock_put(ip->i_gl);
 fail:
-	if (inode->i_state & I_NEW)
-		iget_failed(inode);
-	else
-		iput(inode);
+	iget_failed(inode);
 	return ERR_PTR(error);
 }
 
@@ -221,14 +201,6 @@ struct inode *gfs2_lookup_by_inum(struct gfs2_sbd *sdp, u64 no_addr,
 	if (IS_ERR(inode))
 		goto fail;
 
-	error = gfs2_inode_refresh(GFS2_I(inode));
-	if (error)
-		goto fail_iput;
-
-	/* Pick up the works we bypass in gfs2_inode_lookup */
-	if (inode->i_state & I_NEW) 
-		gfs2_set_iop(inode);
-
 	/* Two extra checks for NFS only */
 	if (no_formal_ino) {
 		error = -ESTALE;

fs/gfs2/inode.h

@@ -96,7 +96,6 @@ static inline int gfs2_check_internal_file_size(struct inode *inode,
 	return -EIO;
 }
 
-extern void gfs2_set_iop(struct inode *inode);
 extern struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned type, 
 				       u64 no_addr, u64 no_formal_ino);
 extern struct inode *gfs2_lookup_by_inum(struct gfs2_sbd *sdp, u64 no_addr,