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authorKen Chen <kenchen@google.com>2007-02-08 17:20:27 -0500
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-02-09 12:25:46 -0500
commit6649a3863232eb2e2f15ea6c622bd8ceacf96d76 (patch)
treec3b77d20afd1e7215186244375f6cdcaad94d4b2 /fs/hugetlbfs
parentf336953bfdee8d5e7f69cb8e080704546541f04b (diff)
[PATCH] hugetlb: preserve hugetlb pte dirty state
__unmap_hugepage_range() is buggy that it does not preserve dirty state of huge_pte when unmapping hugepage range. It causes data corruption in the event of dop_caches being used by sys admin. For example, an application creates a hugetlb file, modify pages, then unmap it. While leaving the hugetlb file alive, comes along sys admin doing a "echo 3 > /proc/sys/vm/drop_caches". drop_pagecache_sb() will happily free all pages that aren't marked dirty if there are no active mapping. Later when application remaps the hugetlb file back and all data are gone, triggering catastrophic flip over on application. Not only that, the internal resv_huge_pages count will also get all messed up. Fix it up by marking page dirty appropriately. Signed-off-by: Ken Chen <kenchen@google.com> Cc: "Nish Aravamudan" <nish.aravamudan@gmail.com> Cc: Adam Litke <agl@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: <stable@kernel.org> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/hugetlbfs')
-rw-r--r--fs/hugetlbfs/inode.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 4f4cd132b571..e6bd553fdc4c 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -449,10 +449,13 @@ static int hugetlbfs_symlink(struct inode *dir,
449} 449}
450 450
451/* 451/*
452 * For direct-IO reads into hugetlb pages 452 * mark the head page dirty
453 */ 453 */
454static int hugetlbfs_set_page_dirty(struct page *page) 454static int hugetlbfs_set_page_dirty(struct page *page)
455{ 455{
456 struct page *head = (struct page *)page_private(page);
457
458 SetPageDirty(head);
456 return 0; 459 return 0;
457} 460}
458 461