From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-x643.google.com ([2607:f8b0:4864:20::643]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gXWXB-0004Rd-9n for linux-mtd@lists.infradead.org; Thu, 13 Dec 2018 19:20:37 +0000 Received: by mail-pl1-x643.google.com with SMTP id p8so1514532plo.2 for ; Thu, 13 Dec 2018 11:20:23 -0800 (PST) From: zhangjun To: Richard Weinberger Cc: Artem Bityutskiy , Adrian Hunter , linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, zhangjun Subject: [PATCH v2] ubifs: fix page_count in ->ubifs_migrate_page() Date: Thu, 13 Dec 2018 14:20:17 -0500 Message-Id: <1544728817-2870-1-git-send-email-openzhangj@gmail.com> List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Because the PagePrivate() in UBIFS is different meanings, alloc_cma() will fail when one dirty page cache located in the type of MIGRATE_CMA If not adjust the 'extra_count' for dirty page, ubifs_migrate_page() -> migrate_page_move_mapping() will always return -EAGAIN for: expected_count += page_has_private(page) This causes the migration to fail until the page cache is cleaned In general, PagePrivate() indicates that buff_head is already bound to this page, and at the same time page_count() will also increase. But UBIFS set private flag when the cache is dirty, and page_count() not increase. Therefore, the expected_count of UBIFS is different from the general case. Signed-off-by: zhangjun --- fs/ubifs/file.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c index 1b78f2e..890dfce 100644 --- a/fs/ubifs/file.c +++ b/fs/ubifs/file.c @@ -1480,8 +1480,17 @@ static int ubifs_migrate_page(struct address_space *mapping, struct page *newpage, struct page *page, enum migrate_mode mode) { int rc; + int extra_count = 0; - rc = migrate_page_move_mapping(mapping, newpage, page, NULL, mode, 0); + /* + * UBIFS uses PG_private as marker and does not raise the page counter. + * migrate_page_move_mapping() expects a incremented counter if + * PG_private is set. Therefore pass -1 as extra_count for this case. + */ + if (page_has_private(page)) + extra_count = -1; + rc = migrate_page_move_mapping(mapping, newpage, page, + NULL, mode, extra_count); if (rc != MIGRATEPAGE_SUCCESS) return rc; -- 2.7.4