Sorry, forgot to commit local changes. ----8<---- >From 321379738fa2359385a38dfac838a83c261a382d Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Date: Wed, 23 Nov 2016 12:05:30 +0300 Subject: [PATCH] mm: fix false-positive WARN_ON() in truncate/invalidate for hugetlb Hugetlb pages have ->index in size of the huge pages (PMD_SIZE or PUD_SIZE), not in PAGE_SIZE as other types of pages. This means we cannot user page_to_pgoff() to check whether we've got the right page for the radix-tree index. Let's introduce page_to_index() which would return radix-tree index for given page. We will be able to get rid of this once hugetlb will be switched to multi-order entries. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Reported-and-tested-by: Doug Nelson <doug.nelson@xxxxxxxxx> Fixes: fc127da085c2 ("truncate: handle file thp") Cc: <stable@xxxxxxxxxxxxxxx> [4.8+] --- include/linux/pagemap.h | 21 +++++++++++++++------ mm/truncate.c | 8 ++++---- 2 files changed, 19 insertions(+), 10 deletions(-) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index dd15d39e1985..7dbe9148b2f8 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -374,16 +374,13 @@ static inline struct page *read_mapping_page(struct address_space *mapping, } /* - * Get the offset in PAGE_SIZE. - * (TODO: hugepage should have ->index in PAGE_SIZE) + * Get index of the page with in radix-tree + * (TODO: remove once hugetlb pages will have ->index in PAGE_SIZE) */ -static inline pgoff_t page_to_pgoff(struct page *page) +static inline pgoff_t page_to_index(struct page *page) { pgoff_t pgoff; - if (unlikely(PageHeadHuge(page))) - return page->index << compound_order(page); - if (likely(!PageTransTail(page))) return page->index; @@ -397,6 +394,18 @@ static inline pgoff_t page_to_pgoff(struct page *page) } /* + * Get the offset in PAGE_SIZE. + * (TODO: hugepage should have ->index in PAGE_SIZE) + */ +static inline pgoff_t page_to_pgoff(struct page *page) +{ + if (unlikely(PageHeadHuge(page))) + return page->index << compound_order(page); + + return page_to_index(page); +} + +/* * Return byte-offset into filesystem object for page. */ static inline loff_t page_offset(struct page *page) diff --git a/mm/truncate.c b/mm/truncate.c index a01cce450a26..8d8c62d89e6d 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -283,7 +283,7 @@ void truncate_inode_pages_range(struct address_space *mapping, if (!trylock_page(page)) continue; - WARN_ON(page_to_pgoff(page) != index); + WARN_ON(page_to_index(page) != index); if (PageWriteback(page)) { unlock_page(page); continue; @@ -371,7 +371,7 @@ void truncate_inode_pages_range(struct address_space *mapping, } lock_page(page); - WARN_ON(page_to_pgoff(page) != index); + WARN_ON(page_to_index(page) != index); wait_on_page_writeback(page); truncate_inode_page(mapping, page); unlock_page(page); @@ -492,7 +492,7 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping, if (!trylock_page(page)) continue; - WARN_ON(page_to_pgoff(page) != index); + WARN_ON(page_to_index(page) != index); /* Middle of THP: skip */ if (PageTransTail(page)) { @@ -612,7 +612,7 @@ int invalidate_inode_pages2_range(struct address_space *mapping, } lock_page(page); - WARN_ON(page_to_pgoff(page) != index); + WARN_ON(page_to_index(page) != index); if (page->mapping != mapping) { unlock_page(page); continue; -- Kirill A. Shutemov -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html