From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f51.google.com (mail-wm0-f51.google.com [74.125.82.51]) by kanga.kvack.org (Postfix) with ESMTP id E25366B0005 for ; Tue, 26 Jan 2016 03:28:55 -0500 (EST) Received: by mail-wm0-f51.google.com with SMTP id r129so94076719wmr.0 for ; Tue, 26 Jan 2016 00:28:55 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id dm6si348470wjb.119.2016.01.26.00.28.54 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 26 Jan 2016 00:28:54 -0800 (PST) Date: Tue, 26 Jan 2016 09:29:04 +0100 From: Jan Kara Subject: Re: mm: WARNING in __delete_from_page_cache Message-ID: <20160126082904.GS24938@quack.suse.cz> References: <20160124230422.GA8439@node.shutemov.name> <20160125122206.GA24938@quack.suse.cz> <1453779754.32645.3.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: <1453779754.32645.3.camel@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Williams, Dan J" Cc: "kirill@shutemov.name" , "jack@suse.cz" , "syzkaller@googlegroups.com" , "linux-kernel@vger.kernel.org" , "kirill.shutemov@linux.intel.com" , "linux-mm@kvack.org" , "dave.hansen@linux.intel.com" , "kcc@google.com" , "vbabka@suse.cz" , "viro@zeniv.linux.org.uk" , "dvyukov@google.com" , "akpm@linux-foundation.org" , "gthelen@google.com" , "willy@linux.intel.com" , "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 26-01-16 03:42:34, Williams, Dan J wrote: > On Mon, 2016-01-25 at 13:22 +0100, Jan Kara wrote: > [..] > > Thanks. Despite the huge list of recipients the author of the changes > > hasn't been CCed :) I've added Dan to CC since he wrote DAX support > > for > > block devices. It seems somehow the write didn't go through the DAX > > path > > but through the standard page cache write path. Ah, I see, only > > file->f_mapping->host has S_DAX set but io_is_direct() which decides > > whether DAX or pagecache path should be used for writes uses file- > > >f_inode > > which is something different for block devices... > > Thanks, yes, the following silences the warning for me: > > 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. > > 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: Matthew Wilcox > 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 > Signed-off-by: Dan Williams The patch looks good to me. You can add: Reviewed-by: Jan Kara Honza > --- > fs/block_dev.c | 5 ----- > include/linux/fs.h | 12 +++++++++++- > 2 files changed, 11 insertions(+), 6 deletions(-) > > diff --git a/fs/block_dev.c b/fs/block_dev.c > index 7b9cd49622b1..277008617b2d 100644 > --- a/fs/block_dev.c > +++ b/fs/block_dev.c > @@ -156,11 +156,6 @@ blkdev_get_block(struct inode *inode, sector_t iblock, > return 0; > } > > -static struct inode *bdev_file_inode(struct file *file) > -{ > - return file->f_mapping->host; > -} > - > static ssize_t > blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset) > { > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 1a2046275cdf..a4c4314eed48 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -1237,6 +1237,11 @@ static inline struct inode *file_inode(const struct file *f) > return f->f_inode; > } > > +static inline struct inode *bdev_file_inode(struct file *file) > +{ > + return file->f_mapping->host; > +} > + > static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl) > { > return locks_lock_inode_wait(file_inode(filp), fl); > @@ -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)); > + struct inode *inode = file_inode(filp); > + > + if (S_ISBLK(inode->i_mode)) > + inode = bdev_file_inode(filp); > + > + return (filp->f_flags & O_DIRECT) || IS_DAX(inode); > } > > static inline int iocb_flags(struct file *file) -- Jan Kara SUSE Labs, CR -- 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