[PATCH] ext4: Fix FLEX_BG and uninit group usage.

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

With FLEX_BG we allocate block bitmap, inode bitmap, and
inode table outside the group. So when initialzing the
uninit block group we don't need to set bits corresponding
to these meta-data in the bitmaps. Also return the right
number of free blocks when counting the available free
blocks in uninit group.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 fs/ext4/balloc.c |   15 ++++++++++++++-
 1 files changed, 14 insertions(+), 1 deletions(-)

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 5c80eb5..fb63f01 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -109,7 +109,14 @@ unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
 
 		for (bit = 0; bit < bit_max; bit++)
 			ext4_set_bit(bit, bh->b_data);
-
+		/*
+		 * With FLEX_BG uninit group we have all the
+		 * blocks available for use. So no need
+		 * to set any bits in bitmap
+		 */
+		 if (EXT4_HAS_INCOMPAT_FEATURE(sb,
+					 EXT4_FEATURE_INCOMPAT_FLEX_BG))
+			return free_blocks;
 		start = ext4_group_first_block_no(sb, block_group);
 
 		/* Set bits for block and inode bitmaps, and inode table */
@@ -126,6 +133,12 @@ unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
 		 */
 		mark_bitmap_end(group_blocks, sb->s_blocksize * 8, bh->b_data);
 	}
+	/*
+	 * With FLEX_BG uninit group we have all the
+	 * blocks available for use.
+	 */
+	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
+		return free_blocks;
 
 	return free_blocks - sbi->s_itb_per_group - 2;
 }
-- 
1.5.5.1.211.g65ea3.dirty