linux-ext4 - ext4_wait_block_bitmap() and ext4_read_block_bitmap_nowait() handle bitmap verification differently

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Message-ID: <CAGW2f1HsP1s+Avuiietg1BqqNeEJJ8g1MOgxHnx-8hqK57QG7Q@mail.gmail.com>
Date:	Thu, 3 Oct 2013 22:45:06 -0400
From:	jon ernst <jonernst07@...il.com>
To:	"linux-ext4@...r.kernel.org List" <linux-ext4@...r.kernel.org>
Subject: ext4_wait_block_bitmap() and ext4_read_block_bitmap_nowait() handle
 bitmap verification differently

Hi,

I found that ext4_wait_block_bitmap() and
ext4_read_block_bitmap_nowait() handle bitmap verification
differently.
wait_block_bitmap() calls ext4_validate_block_bitmap() all the time.
But  read_block_bitmap_nowait() checks EXT4_BG_BLOCK_UNINIT, if it
meets, it will skip ext4_validate_block_bitmap()

In my opinion, they'd better do same thing.
In that way, we can also return "fail" in ext4_valid_block_bitmap()
method when we meet FLEX_BG.



diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index dc5d572..366807a 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -319,7 +319,7 @@ static ext4_fsblk_t ext4_valid_block_bitmap(struct
super_block *sb,
                 * or it has to also read the block group where the bitmaps
                 * are located to verify they are set.
                 */
-               return 0;
+               return 1;
        }
        group_first_block = ext4_group_first_block_no(sb, block_group);

@@ -472,8 +472,12 @@ int ext4_wait_block_bitmap(struct super_block
*sb, ext4_group_t block_group,
                return 1;
        }
        clear_buffer_new(bh);
-       /* Panic or remount fs read-only if block bitmap is invalid */
-       ext4_validate_block_bitmap(sb, desc, block_group, bh);
+
+       if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
+        return 0;
+        }
+       /* Panic or remount fs read-only if block bitmap is invalid */
+       ext4_validate_block_bitmap(sb, desc, block_group, bh);
        /* ...but check for error just in case errors=continue. */
        return !buffer_verified(bh);
 }
--
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