jbd/jbd2: use non-movable memory for the jbd superblock

Sicne the jbd/jbd2 superblock is not released until the file system is
unmounted, allocate the buffer cache from the non-moveable area to
allow page migration and CMA allocations to more easily succeed.
Signed-off-by: Gioh Kim <gioh.kim@lge.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

fs/jbd/journal.c

@@ -886,7 +886,7 @@ journal_t * journal_init_inode (struct inode *inode)
 		goto out_err;
 	}
 
-	bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
+	bh = getblk_unmovable(journal->j_dev, blocknr, journal->j_blocksize);
 	if (!bh) {
 		printk(KERN_ERR
 		       "%s: Cannot get buffer for journal superblock\n",

fs/jbd2/journal.c

@@ -1237,7 +1237,7 @@ journal_t * jbd2_journal_init_inode (struct inode *inode)
 		goto out_err;
 	}
 
-	bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
+	bh = getblk_unmovable(journal->j_dev, blocknr, journal->j_blocksize);
 	if (!bh) {
 		printk(KERN_ERR
 		       "%s: Cannot get buffer for journal superblock\n",