From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Lameter Subject: [30/41] Add VM_BUG_ONs to check for correct page order Date: Mon, 10 Sep 2007 23:04:20 -0700 Message-ID: <20070911060432.546240009@sgi.com> References: <20070911060349.993975297@sgi.com> Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org To: torvalds@linux-foundation.org Return-path: Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:50605 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1761261AbXIKGEd (ORCPT ); Tue, 11 Sep 2007 02:04:33 -0400 Cc: Christoph Hellwig , Mel Gorman Cc: William Lee Irwin III , David Chinner Cc: Jens Axboe , Badari Pulavarty Cc: Maxim Levitsky , Fengguang Wu Cc: swin wang , totty.lu@gmail.com, hugh@veritas.com Cc: joern@lazybastard.org Content-Disposition: inline; filename=0030-Add-VM_BUG_ONs-to-check-for-correct-page-order.patch Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Before allowing different page orders it may be wise to get some checkpoints in at various places. Checkpoints will help debugging whenever a wrong order page shows up in a mapping. Helps when converting new filesystems to utilize larger pages. Signed-off-by: Christoph Lameter --- fs/buffer.c | 1 + mm/filemap.c | 18 +++++++++++++++--- 2 files changed, 16 insertions(+), 3 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index 130ea0d..eaec65e 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -893,6 +893,7 @@ struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, long offset; unsigned int page_size = page_cache_size(page->mapping); + BUG_ON(size > page_size); try_again: head = NULL; offset = page_size; diff --git a/mm/filemap.c b/mm/filemap.c index bfe6eaa..3a0ae48 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -128,6 +128,7 @@ void remove_from_page_cache(struct page *page) struct address_space *mapping = page->mapping; BUG_ON(!PageLocked(page)); + VM_BUG_ON(mapping_order(mapping) != page_cache_page_order(page)); write_lock_irq(&mapping->tree_lock); __remove_from_page_cache(page); @@ -269,6 +270,7 @@ int wait_on_page_writeback_range(struct address_space *mapping, if (page->index > end) continue; + VM_BUG_ON(mapping_order(mapping) != page_cache_page_order(page)); wait_on_page_writeback(page); if (PageError(page)) ret = -EIO; @@ -440,6 +442,7 @@ int add_to_page_cache(struct page *page, struct address_space *mapping, { int error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM); + VM_BUG_ON(mapping_order(mapping) != page_cache_page_order(page)); if (error == 0) { write_lock_irq(&mapping->tree_lock); error = radix_tree_insert(&mapping->page_tree, offset, page); @@ -599,8 +602,10 @@ struct page * find_get_page(struct address_space *mapping, unsigned long offset) read_lock_irq(&mapping->tree_lock); page = radix_tree_lookup(&mapping->page_tree, offset); - if (page) + if (page) { + VM_BUG_ON(mapping_order(mapping) != page_cache_page_order(page)); page_cache_get(page); + } read_unlock_irq(&mapping->tree_lock); return page; } @@ -625,6 +630,7 @@ struct page *find_lock_page(struct address_space *mapping, repeat: page = radix_tree_lookup(&mapping->page_tree, offset); if (page) { + VM_BUG_ON(mapping_order(mapping) != page_cache_page_order(page)); page_cache_get(page); if (TestSetPageLocked(page)) { read_unlock_irq(&mapping->tree_lock); @@ -715,8 +721,10 @@ unsigned find_get_pages(struct address_space *mapping, pgoff_t start, read_lock_irq(&mapping->tree_lock); ret = radix_tree_gang_lookup(&mapping->page_tree, (void **)pages, start, nr_pages); - for (i = 0; i < ret; i++) + for (i = 0; i < ret; i++) { + VM_BUG_ON(mapping_order(mapping) != page_cache_page_order(pages[i])); page_cache_get(pages[i]); + } read_unlock_irq(&mapping->tree_lock); return ret; } @@ -746,6 +754,7 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index, if (pages[i]->mapping == NULL || pages[i]->index != index) break; + VM_BUG_ON(mapping_order(mapping) != page_cache_page_order(pages[i])); page_cache_get(pages[i]); index++; } @@ -774,8 +783,10 @@ unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index, read_lock_irq(&mapping->tree_lock); ret = radix_tree_gang_lookup_tag(&mapping->page_tree, (void **)pages, *index, nr_pages, tag); - for (i = 0; i < ret; i++) + for (i = 0; i < ret; i++) { + VM_BUG_ON(mapping_order(mapping) != page_cache_page_order(pages[i])); page_cache_get(pages[i]); + } if (ret) *index = pages[ret - 1]->index + 1; read_unlock_irq(&mapping->tree_lock); @@ -2233,6 +2244,7 @@ int try_to_release_page(struct page *page, gfp_t gfp_mask) struct address_space * const mapping = page->mapping; BUG_ON(!PageLocked(page)); + VM_BUG_ON(mapping_order(mapping) != page_cache_page_order(page)); if (PageWriteback(page)) return 0; -- 1.5.2.5 --