linux-ext4 - Re: [PATCH] resize2fs: clear uninit BG if allocating from new group

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Date:	Thu, 14 Jan 2016 10:20:22 -0700
From:	Andreas Dilger <adilger@...ger.ca>
To:	Eric Sandeen <sandeen@...hat.com>
Cc:	linux-ext4@...r.kernel.org
Subject: Re: [PATCH] resize2fs: clear uninit BG if allocating from new group

On Jan 14, 2016, at 07:09, Eric Sandeen <sandeen@...hat.com> wrote:
> 
>> On 9/17/15 5:42 PM, Eric Sandeen wrote:
>> If resize2fs_get_alloc_block() allocates from a BLOCK_UNINIT
>> group, nothing clears the UNINIT flag, so it is skipped when we
>> go to write out modified bitmaps.  This leads to post-resize2fs
>> e2fsck errors; used blocks in UNINIT groups, not marked in the
>> block bitmap.
>> 
>> This shamelessly cuts & pastes clear_block_uninit() into
>> resize2fs.c, and my problem goes away.
> 
> Ping on this?

My only minor concern is about the code duplication. Is there a common place this could be moved?

Cheers, Andreas

>> Signed-off-by: Eric Sandeen <sandeen@...hat.com>
>> ---
>> 
>> I've kind of lost the thread on resize2fs lately, so maybe this is
>> a hack job?  At least it highlights the issue, even if it's not
>> quite right.  Passes "make check" here and seems ok to me...
>> 
>> Thanks,
>> -Eric
>> 
>> diff --git a/resize/resize2fs.c b/resize/resize2fs.c
>> index 07c6a0c..0f202bd 100644
>> --- a/resize/resize2fs.c
>> +++ b/resize/resize2fs.c
>> @@ -1614,12 +1614,27 @@ static blk64_t get_new_block(ext2_resize_t rfs)
>>    }
>> }
>> 
>> +static void clear_block_uninit(ext2_filsys fs, dgrp_t group)
>> +{
>> +    if (!ext2fs_has_group_desc_csum(fs) ||
>> +        !(ext2fs_bg_flags_test(fs, group, EXT2_BG_BLOCK_UNINIT)))
>> +        return;
>> +
>> +    /* uninit block bitmaps are now initialized in read_bitmaps() */
>> +
>> +    ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
>> +    ext2fs_group_desc_csum_set(fs, group);
>> +    ext2fs_mark_super_dirty(fs);
>> +    ext2fs_mark_bb_dirty(fs);
>> +}
>> +
>> static errcode_t resize2fs_get_alloc_block(ext2_filsys fs,
>>                       blk64_t goal EXT2FS_ATTR((unused)),
>>                       blk64_t *ret)
>> {
>>    ext2_resize_t rfs = (ext2_resize_t) fs->priv_data;
>>    blk64_t blk;
>> +    int group;
>> 
>>    blk = get_new_block(rfs);
>>    if (!blk)
>> @@ -1632,6 +1647,12 @@ static errcode_t resize2fs_get_alloc_block(ext2_filsys fs,
>> 
>>    ext2fs_mark_block_bitmap2(rfs->old_fs->block_map, blk);
>>    ext2fs_mark_block_bitmap2(rfs->new_fs->block_map, blk);
>> +
>> +    group = ext2fs_group_of_blk2(rfs->old_fs, blk);
>> +    clear_block_uninit(rfs->old_fs, group);
>> +    group = ext2fs_group_of_blk2(rfs->new_fs, blk);
>> +    clear_block_uninit(rfs->new_fs, group);
>> +
>>    *ret = (blk64_t) blk;
>>    return 0;
>> }
>> 
>> --
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> 
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