From 2aeb3db17fc33443d21b11d7121c5627d55717c6 Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Date: Thu, 30 Aug 2007 23:56:33 -0700 Subject: [PATCH] eCryptfs: fix possible fault in ecryptfs_sync_page This will avoid a possible fault in ecryptfs_sync_page(). In the function, eCryptfs calls sync_page() method of a lower filesystem without checking its existence. However, there are many filesystems that don't have this method including network filesystems such as NFS, AFS, and so forth. They may fail when an eCryptfs page is waiting for lock. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Acked-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> --- fs/ecryptfs/mmap.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c index e4ab7bc14efed..fd3f94d4a6684 100644 --- a/fs/ecryptfs/mmap.c +++ b/fs/ecryptfs/mmap.c @@ -834,7 +834,8 @@ static void ecryptfs_sync_page(struct page *page) ecryptfs_printk(KERN_DEBUG, "find_lock_page failed\n"); return; } - lower_page->mapping->a_ops->sync_page(lower_page); + if (lower_page->mapping->a_ops->sync_page) + lower_page->mapping->a_ops->sync_page(lower_page); ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n", lower_page->index); unlock_page(lower_page); -- GitLab