Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> writes:
> On Wed, 13 Jan 2010 21:14:09 +0900
> OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx> wrote:
>
>>
>> If __block_prepare_write() was failed in block_write_begin(), the
>> allocated blocks can be outside of ->i_size.
>>
>> But new truncate_pagecache() in vmtuncate() does nothing if new < old.
>> It means the above usage is not working anymore.
>>
>> So, this patch fixes it by removing "new < old" check. It would need
>> more cleanup/change. But, now -rc and truncate working is in progress,
>> so, this tried to fix it minimum change.
>>
>> Acked-by: Nick Piggin <npiggin@xxxxxxx>
>> Signed-off-by: OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
>> ---
>>
>> mm/truncate.c | 28 +++++++++++++---------------
>> 1 file changed, 13 insertions(+), 15 deletions(-)
>>
>> diff -puN mm/truncate.c~truncate_pagecache-fix mm/truncate.c
>> --- linux-2.6/mm/truncate.c~truncate_pagecache-fix 2010-01-12 05:43:06.000000000 +0900
>> +++ linux-2.6-hirofumi/mm/truncate.c 2010-01-12 05:43:06.000000000 +0900
>> @@ -522,22 +522,20 @@ EXPORT_SYMBOL_GPL(invalidate_inode_pages
>> */
>> void truncate_pagecache(struct inode *inode, loff_t old, loff_t new)
>> {
>> - if (new < old) {
>> - struct address_space *mapping = inode->i_mapping;
>> + struct address_space *mapping = inode->i_mapping;
>>
>> - /*
>> - * unmap_mapping_range is called twice, first simply for
>> - * efficiency so that truncate_inode_pages does fewer
>> - * single-page unmaps. However after this first call, and
>> - * before truncate_inode_pages finishes, it is possible for
>> - * private pages to be COWed, which remain after
>> - * truncate_inode_pages finishes, hence the second
>> - * unmap_mapping_range call must be made for correctness.
>> - */
>> - unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1);
>> - truncate_inode_pages(mapping, new);
>> - unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1);
>> - }
>> + /*
>> + * unmap_mapping_range is called twice, first simply for
>> + * efficiency so that truncate_inode_pages does fewer
>> + * single-page unmaps. However after this first call, and
>> + * before truncate_inode_pages finishes, it is possible for
>> + * private pages to be COWed, which remain after
>> + * truncate_inode_pages finishes, hence the second
>> + * unmap_mapping_range call must be made for correctness.
>> + */
>> + unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1);
>> + truncate_inode_pages(mapping, new);
>> + unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1);
>> }
>> EXPORT_SYMBOL(truncate_pagecache);
>
> The fix was applied to 2.6.33-rcX
> (cedabed49b39b4319bccc059a63344b6232b619c), appears to be needed in
> 2.6.32.x but no cc:stable's are present?
Ah, yes. I forgot to add "Cc: stable". Please apply this to 2.6.32.x.
--
OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
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