Commit e4c6f8be authored Jul 29, 2009 by Eric Sandeen Committed by Linus Torvalds Jul 29, 2009

hugetlbfs: fix i_blocks accounting



As reported in Red Hat bz #509671, i_blocks for files on hugetlbfs get
accounting wrong when doing something like:

   $ > foo
   $ date  > foo
   date: write error: Invalid argument
   $ /usr/bin/stat foo
     File: `foo'
     Size: 0          Blocks: 18446744073709547520 IO Block: 2097152 regular
...

This is because hugetlb_unreserve_pages() is unconditionally removing
blocks_per_huge_page(h) on each call rather than using the freed amount.
If there were 0 blocks, it goes negative, resulting in the above.

This is a regression from commit a5516438
("hugetlb: modular state for hugetlb page size")

which did:

-	inode->i_blocks -= BLOCKS_PER_HUGEPAGE * freed;
+	inode->i_blocks -= blocks_per_huge_page(h);

so just put back the freed multiplier, and it's all happy again.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Acked-by: Andi Kleen <andi@firstfloor.org>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 65909814

mm/hugetlb.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -2370,7 +2370,7 @@ void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
		long chg = region_truncate(&inode->i_mapping->private_list, offset);

		spin_lock(&inode->i_lock);
		inode->i_blocks -= blocks_per_huge_page(h);
		inode->i_blocks -= (blocks_per_huge_page(h) * freed);
		spin_unlock(&inode->i_lock);

		hugetlb_put_quota(inode->i_mapping, (chg - freed));

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