[patch 01/28] hugetlbfs: fix i_blocks accounting

Greg KH
2009-08-13T19:47:42Z

[-- Attachment #1: hugetlbfs-fix-i_blocks-accounting.patch --]
[-- Type: text/plain, Size: 1795 bytes --]

2.6.27-stable review patch. If anyone has any objections, please let us know.

------------------

From: Eric Sandeen <sandeen@sandeen.net>

commit e4c6f8bed01f9f9a5c607bd689bf67e7b8a36bd8 upstream.

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 a5516438959d90b071ff0a484ce4f3f523dc3152
("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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
mm/hugetlb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2257,7 +2257,7 @@ void hugetlb_unreserve_pages(struct inod
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));