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vfs: Fix vmtruncate() regression 

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@suse.de>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
OGAWA Hirofumi 2010-01-13 21:14:09 +09:00 committed by Linus Torvalds
parent e80c14e1ae
commit cedabed49b
1 changed files with 13 additions and 15 deletions
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28
mm/truncate.c
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@ -522,22 +522,20 @@ EXPORT_SYMBOL_GPL(invalidate_inode_pages2);
*/ */
void truncate_pagecache(struct inode *inode, loff_t old, loff_t new) 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 * unmap_mapping_range is called twice, first simply for
* efficiency so that truncate_inode_pages does fewer * efficiency so that truncate_inode_pages does fewer
* single-page unmaps. However after this first call, and * single-page unmaps. However after this first call, and
* before truncate_inode_pages finishes, it is possible for * before truncate_inode_pages finishes, it is possible for
* private pages to be COWed, which remain after * private pages to be COWed, which remain after
* truncate_inode_pages finishes, hence the second * truncate_inode_pages finishes, hence the second
* unmap_mapping_range call must be made for correctness. * unmap_mapping_range call must be made for correctness.
*/ */
unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1); unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1);
truncate_inode_pages(mapping, new); truncate_inode_pages(mapping, new);
unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1); unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1);
}
} }
EXPORT_SYMBOL(truncate_pagecache); EXPORT_SYMBOL(truncate_pagecache);