ext4/balloc.c:read_block_bitmap(): inconsequent NULL checking

ext4/balloc.c:read_block_bitmap(): inconsequent NULL checking

[Adrian Bunk]

Commit 7c9e69faa28027913ee059c285a5ea8382e24b5d results in the following 
inconsequent NULL checking in fs/ext4/balloc.c:

<--  snip  -->

...
struct buffer_head *
read_block_bitmap(struct super_block *sb, unsigned int block_group)
{
...
        if (!bh)
                ext4_error (sb, __FUNCTION__,
                            "Cannot read block bitmap - "
                            "block_group = %d, block_bitmap = %llu",
                            block_group, bitmap_blk);

        /* check whether block bitmap block number is set */
        if (!block_in_use(bitmap_blk, sb, bh->b_data)) {
...                                       ^^^^^^^^^^

<--  snip  -->

Spotted by the Coverity checker.

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

Re: ext4/balloc.c:read_block_bitmap(): inconsequent NULL checking

[Aneesh Kumar K.V]

I checked rest of the ext4 sources to make sure we return properly after ext4_error.
I guess i have taken care of all the places.

-aneesh

Adrian Bunk wrote:
> Commit 7c9e69faa28027913ee059c285a5ea8382e24b5d results in the following 
> inconsequent NULL checking in fs/ext4/balloc.c:
> 
> <--  snip  -->
> 
> ...
> struct buffer_head *
> read_block_bitmap(struct super_block *sb, unsigned int block_group)
> {
> ...
>         if (!bh)
>                 ext4_error (sb, __FUNCTION__,
>                             "Cannot read block bitmap - "
>                             "block_group = %d, block_bitmap = %llu",
>                             block_group, bitmap_blk);
> 
>         /* check whether block bitmap block number is set */
>         if (!block_in_use(bitmap_blk, sb, bh->b_data)) {
> ...                                       ^^^^^^^^^^
> 
> <--  snip  -->
> 
> Spotted by the Coverity checker.
> 
> 



>From 5c04ec0d8e43ef582cec2856f262b575376233ba Mon Sep 17 00:00:00 2001
From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date: Fri, 19 Oct 2007 20:10:17 +0530
Subject: [PATCH] ext4: Return after ext4_error in case of failures

This fix some instances where we were continuing
after marking the file system errors.
Even though ext4_error mark the file system read only
and panic depending on mount option it is good
to handle the return properly.

Reported by:
Adrian Bunk <bunk@kernel.org>

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 fs/ext4/balloc.c |   12 +++++++++---
 1 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index e906b65..8517dd7 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -234,11 +234,13 @@ read_block_bitmap(struct super_block *sb, unsigned int block_group)
 	} else {
 		bh = sb_bread(sb, bitmap_blk);
 	}
-	if (!bh)
+	if (!bh) {
 		ext4_error (sb, __FUNCTION__,
 			    "Cannot read block bitmap - "
 			    "block_group = %d, block_bitmap = %llu",
 			    block_group, bitmap_blk);
+		return NULL;
+	}
 
 	/* check whether block bitmap block number is set */
 	if (!block_in_use(bitmap_blk, sb, bh->b_data)) {
@@ -628,11 +630,13 @@ do_more:
 	    in_range(ext4_inode_bitmap(sb, desc), block, count) ||
 	    in_range(block, ext4_inode_table(sb, desc), sbi->s_itb_per_group) ||
 	    in_range(block + count - 1, ext4_inode_table(sb, desc),
-		     sbi->s_itb_per_group))
+		     sbi->s_itb_per_group)) {
 		ext4_error (sb, "ext4_free_blocks",
 			    "Freeing blocks in system zones - "
 			    "Block = %llu, count = %lu",
 			    block, count);
+		goto error_return;
+	}
 
 	/*
 	 * We are about to start releasing blocks in the bitmap,
@@ -1733,11 +1737,13 @@ allocated:
 	    in_range(ret_block, ext4_inode_table(sb, gdp),
 		     EXT4_SB(sb)->s_itb_per_group) ||
 	    in_range(ret_block + num - 1, ext4_inode_table(sb, gdp),
-		     EXT4_SB(sb)->s_itb_per_group))
+		     EXT4_SB(sb)->s_itb_per_group)) {
 		ext4_error(sb, "ext4_new_block",
 			    "Allocating block in system zone - "
 			    "blocks from %llu, length %lu",
 			     ret_block, num);
+		goto out;
+	}
 
 	performed_allocation = 1;
 
-- 
1.5.3.4.206.g58ba4-dirty