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?
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