GFS2: Make rename not save dirent location

This patch fixes a regression in the patch "GFS2: Remember directory
insert point", commit 2b47dad866d04f14c328f888ba5406057b8c7d33.
The problem had to do with the rename function: The function found
space for the new dirent, and remembered that location. But then the
old dirent was removed, which often moved the eligible location for
the renamed dirent. Putting the new dirent at the saved location
caused file system corruption.

This patch adds a new "save_loc" variable to struct gfs2_diradd.
If 1, the dirent location is saved. If 0, the dirent location is not
saved and the buffer_head is released as per previous behavior.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
index 1a349f9..5d4261ff5 100644
--- a/fs/gfs2/dir.c
+++ b/fs/gfs2/dir.c
@@ -2100,8 +2100,13 @@
 	}
 	if (IS_ERR(dent))
 		return PTR_ERR(dent);
-	da->bh = bh;
-	da->dent = dent;
+
+	if (da->save_loc) {
+		da->bh = bh;
+		da->dent = dent;
+	} else {
+		brelse(bh);
+	}
 	return 0;
 }
 
diff --git a/fs/gfs2/dir.h b/fs/gfs2/dir.h
index 126c65d..e1b309c 100644
--- a/fs/gfs2/dir.h
+++ b/fs/gfs2/dir.h
@@ -23,6 +23,7 @@
 	unsigned nr_blocks;
 	struct gfs2_dirent *dent;
 	struct buffer_head *bh;
+	int save_loc;
 };
 
 extern struct inode *gfs2_dir_search(struct inode *dir,
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 9516f5c..fcf42ea 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -600,7 +600,7 @@
 	int error, free_vfs_inode = 0;
 	u32 aflags = 0;
 	unsigned blocks = 1;
-	struct gfs2_diradd da = { .bh = NULL, };
+	struct gfs2_diradd da = { .bh = NULL, .save_loc = 1, };
 
 	if (!name->len || name->len > GFS2_FNAMESIZE)
 		return -ENAMETOOLONG;
@@ -900,7 +900,7 @@
 	struct gfs2_inode *ip = GFS2_I(inode);
 	struct gfs2_holder ghs[2];
 	struct buffer_head *dibh;
-	struct gfs2_diradd da = { .bh = NULL, };
+	struct gfs2_diradd da = { .bh = NULL, .save_loc = 1, };
 	int error;
 
 	if (S_ISDIR(inode->i_mode))
@@ -1338,7 +1338,7 @@
 	struct gfs2_rgrpd *nrgd;
 	unsigned int num_gh;
 	int dir_rename = 0;
-	struct gfs2_diradd da = { .nr_blocks = 0, };
+	struct gfs2_diradd da = { .nr_blocks = 0, .save_loc = 0, };
 	unsigned int x;
 	int error;