From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f177.google.com (mail-pf0-f177.google.com [209.85.192.177]) by kanga.kvack.org (Postfix) with ESMTP id 35BE66B0009 for ; Wed, 27 Jan 2016 17:04:29 -0500 (EST) Received: by mail-pf0-f177.google.com with SMTP id 65so11486935pfd.2 for ; Wed, 27 Jan 2016 14:04:29 -0800 (PST) Received: from mga11.intel.com (mga11.intel.com. [192.55.52.93]) by mx.google.com with ESMTP id iu1si11997803pac.43.2016.01.27.14.04.28 for ; Wed, 27 Jan 2016 14:04:28 -0800 (PST) Date: Wed, 27 Jan 2016 15:04:21 -0700 From: Ross Zwisler Subject: Re: mm: WARNING in __delete_from_page_cache Message-ID: <20160127220421.GA6634@linux.intel.com> References: <20160124230422.GA8439@node.shutemov.name> <20160125122206.GA24938@quack.suse.cz> <1453779754.32645.3.camel@intel.com> <20160126125456.GK2948@linux.intel.com> <20160126133636.GE23820@quack.suse.cz> <1453827566.32645.5.camel@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1453827566.32645.5.camel@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Williams, Dan J" Cc: "jack@suse.cz" , "willy@linux.intel.com" , "syzkaller@googlegroups.com" , "linux-kernel@vger.kernel.org" , "kirill.shutemov@linux.intel.com" , "linux-mm@kvack.org" , "kcc@google.com" , "dave.hansen@linux.intel.com" , "vbabka@suse.cz" , "viro@zeniv.linux.org.uk" , "dvyukov@google.com" , "akpm@linux-foundation.org" , "gthelen@google.com" , "kirill@shutemov.name" , "linux-fsdevel@vger.kernel.org" , "mhocko@suse.com" , "jack@suse.com" , "glider@google.com" , "sasha.levin@oracle.com" , "Wilcox, Matthew R" , "j-nomura@ce.jp.nec.com" On Tue, Jan 26, 2016 at 04:59:27PM +0000, Williams, Dan J wrote: > On Tue, 2016-01-26 at 14:36 +0100, Jan Kara wrote: > > On Tue 26-01-16 07:54:56, Matthew Wilcox wrote: > > > On Tue, Jan 26, 2016 at 03:42:34AM +0000, Williams, Dan J wrote: > > > > @@ -2907,7 +2912,12 @@ extern void replace_mount_options(struct > > > > super_block *sb, char *options); > > > > > > > > static inline bool io_is_direct(struct file *filp) > > > > { > > > > - return (filp->f_flags & O_DIRECT) || > > > > IS_DAX(file_inode(filp)); > > > > > > I think this should just be a one-liner: > > > > > > - return (filp->f_flags & O_DIRECT) || > > > IS_DAX(file_inode(filp)); > > > + return (filp->f_flags & O_DIRECT) || IS_DAX(filp- > > > >f_mapping->host); > > > > > > This does the right thing for block device inodes and filesystem > > > inodes. > > > (see the opening stanzas of __dax_fault for an example). > > > > Ah, right. This looks indeed better. > > > > > Oh, yeah, looks good. > > 8<---- (git am --scissors) > Subject: fs, block: force direct-I/O for dax-enabled block devices > > From: Dan Williams > > Similar to the file I/O path, re-direct all I/O to the DAX path for I/O > to a block-device special file. Both regular files and device special > files can use the common filp->f_mapping->host lookup to determing is > DAX is enabled. > > Otherwise, we confuse the DAX code that does not expect to find live > data in the page cache: > > ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 7676 at mm/filemap.c:217 > __delete_from_page_cache+0x9f6/0xb60() > Modules linked in: > CPU: 0 PID: 7676 Comm: a.out Not tainted 4.4.0+ #276 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > 00000000ffffffff ffff88006d3f7738 ffffffff82999e2d 0000000000000000 > ffff8800620a0000 ffffffff86473d20 ffff88006d3f7778 ffffffff81352089 > ffffffff81658d36 ffffffff86473d20 00000000000000d9 ffffea0000009d60 > Call Trace: > [< inline >] __dump_stack lib/dump_stack.c:15 > [] dump_stack+0x6f/0xa2 lib/dump_stack.c:50 > [] warn_slowpath_common+0xd9/0x140 kernel/panic.c:482 > [] warn_slowpath_null+0x29/0x30 kernel/panic.c:515 > [] __delete_from_page_cache+0x9f6/0xb60 mm/filemap.c:217 > [] delete_from_page_cache+0x112/0x200 mm/filemap.c:244 > [] __dax_fault+0x859/0x1800 fs/dax.c:487 > [] blkdev_dax_fault+0x26/0x30 fs/block_dev.c:1730 > [< inline >] wp_pfn_shared mm/memory.c:2208 > [] do_wp_page+0xc85/0x14f0 mm/memory.c:2307 > [< inline >] handle_pte_fault mm/memory.c:3323 > [< inline >] __handle_mm_fault mm/memory.c:3417 > [] handle_mm_fault+0x2483/0x4640 mm/memory.c:3446 > [] __do_page_fault+0x376/0x960 arch/x86/mm/fault.c:1238 > [] trace_do_page_fault+0xe8/0x420 arch/x86/mm/fault.c:1331 > [] do_async_page_fault+0x14/0xd0 arch/x86/kernel/kvm.c:264 > [] async_page_fault+0x28/0x30 arch/x86/entry/entry_64.S:986 > [] entry_SYSCALL_64_fastpath+0x16/0x7a > arch/x86/entry/entry_64.S:185 > ---[ end trace dae21e0f85f1f98c ]--- > > Cc: Ross Zwisler > Fixes: 5a023cdba50c ("block: enable dax for raw block devices") > Reported-by: Dmitry Vyukov > Reported-by: Kirill A. Shutemov > Suggested-by: Jan Kara > Reviewed-by: Jan Kara > Suggested-by: Matthew Wilcox > Signed-off-by: Dan Williams I had a test case where I was hitting a warning while inserting into the page cache when the inode was supposed to be DAX, and this clears up my issue as well. Tested-by: Ross Zwisler > --- > include/linux/fs.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 1a2046275cdf..b10002d4a5f5 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -2907,7 +2907,7 @@ extern void replace_mount_options(struct super_block *sb, char *options); > > static inline bool io_is_direct(struct file *filp) > { > - return (filp->f_flags & O_DIRECT) || IS_DAX(file_inode(filp)); > + return (filp->f_flags & O_DIRECT) || IS_DAX(filp->f_mapping->host); > } > > static inline int iocb_flags(struct file *file) > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org