1 files changed, 44 insertions, 19 deletions

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index f9e2cd8..4bbd07a 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -336,10 +336,10 @@ err_out:
  * Return buffer_head on success or NULL in case of failure.
  */
 struct buffer_head *
-ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
+ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group)
 {
 	struct ext4_group_desc *desc;
-	struct buffer_head *bh = NULL;
+	struct buffer_head *bh;
 	ext4_fsblk_t bitmap_blk;
 
 	desc = ext4_get_group_desc(sb, block_group, NULL);
@@ -348,9 +348,9 @@ ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
 	bitmap_blk = ext4_block_bitmap(sb, desc);
 	bh = sb_getblk(sb, bitmap_blk);
 	if (unlikely(!bh)) {
-		ext4_error(sb, "Cannot read block bitmap - "
-			    "block_group = %u, block_bitmap = %llu",
-			    block_group, bitmap_blk);
+		ext4_error(sb, "Cannot get buffer for block bitmap - "
+			   "block_group = %u, block_bitmap = %llu",
+			   block_group, bitmap_blk);
 		return NULL;
 	}
 
@@ -382,25 +382,50 @@ ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
 		return bh;
 	}
 	/*
-	 * submit the buffer_head for read. We can
-	 * safely mark the bitmap as uptodate now.
-	 * We do it here so the bitmap uptodate bit
-	 * get set with buffer lock held.
+	 * submit the buffer_head for reading
 	 */
+	set_buffer_new(bh);
 	trace_ext4_read_block_bitmap_load(sb, block_group);
-	set_bitmap_uptodate(bh);
-	if (bh_submit_read(bh) < 0) {
-		put_bh(bh);
+	bh->b_end_io = ext4_end_bitmap_read;
+	get_bh(bh);
+	submit_bh(READ, bh);
+	return bh;
+}
+
+/* Returns 0 on success, 1 on error */
+int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group,
+			   struct buffer_head *bh)
+{
+	struct ext4_group_desc *desc;
+
+	if (!buffer_new(bh))
+		return 0;
+	desc = ext4_get_group_desc(sb, block_group, NULL);
+	if (!desc)
+		return 1;
+	wait_on_buffer(bh);
+	if (!buffer_uptodate(bh)) {
 		ext4_error(sb, "Cannot read block bitmap - "
-			    "block_group = %u, block_bitmap = %llu",
-			    block_group, bitmap_blk);
-		return NULL;
+			   "block_group = %u, block_bitmap = %llu",
+			   block_group, (unsigned long long) bh->b_blocknr);
+		return 1;
 	}
+	clear_buffer_new(bh);
+	/* Panic or remount fs read-only if block bitmap is invalid */
 	ext4_valid_block_bitmap(sb, desc, block_group, bh);
-	/*
-	 * file system mounted not to panic on error,
-	 * continue with corrupt bitmap
-	 */
+	return 0;
+}
+
+struct buffer_head *
+ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
+{
+	struct buffer_head *bh;
+
+	bh = ext4_read_block_bitmap_nowait(sb, block_group);
+	if (ext4_wait_block_bitmap(sb, block_group, bh)) {
+		put_bh(bh);
+		return NULL;
+	}
 	return bh;
 }