Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751772Ab0AZFs5 (ORCPT ); Tue, 26 Jan 2010 00:48:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750821Ab0AZFsy (ORCPT ); Tue, 26 Jan 2010 00:48:54 -0500 Received: from waste.org ([173.11.57.241]:53489 "EHLO waste.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750756Ab0AZFsy (ORCPT ); Tue, 26 Jan 2010 00:48:54 -0500 Subject: Re: UBIFS assert failed in ubifs_dirty_inode From: Matt Mackall To: dedekind1@gmail.com Cc: Jeff Angielski , linux-mtd@lists.infradead.org, LKML , Herbert Xu In-Reply-To: <1264480808.2401.78.camel@localhost.localdomain> References: <4B591573.60602@theptrgroup.com> <1264480808.2401.78.camel@localhost.localdomain> Content-Type: text/plain; charset="UTF-8" Date: Mon, 25 Jan 2010 23:48:48 -0600 Message-ID: <1264484928.3536.1017.camel@calx> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4224 Lines: 125 On Tue, 2010-01-26 at 06:40 +0200, Artem Bityutskiy wrote: > On Thu, 2010-01-21 at 22:03 -0500, Jeff Angielski wrote: > > I am trying use an UBIFS root filesystem on my PowerPC MPC8544 but I am > > seeing some intermitent problems with "UBIFS assert failed in > > ubifs_dirty_inode" errors. > > > > On the first boot after I program the NAND with a fresh UBI image, > > everything seems to work ok. > > > > After that, on subsequent powercycles or reboots, I sometimes see a boot > > with the following error: > > > > [ 5.984232] UBIFS assert failed in ubifs_dirty_inode at 377 (pid 1011) > > Interesting. > > The stack trace for this assertion is: > > [ 42.724193] [df121e60] [c00070f8] show_stack+0x3c/0x17c (unreliable) > [ 42.730566] [df121ea0] [c017e754] ubifs_dirty_inode+0xe0/0xe4 > [ 42.736325] [df121eb0] [c00c6fbc] __mark_inode_dirty+0x3c/0x16c > [ 42.742260] [df121ec0] [c01f9034] random_write+0x8c/0xa4 > [ 42.747584] [df121ef0] [c00a4d2c] vfs_write+0xb4/0x184 > [ 42.752730] [df121f10] [c00a53e8] sys_write+0x4c/0x90 > [ 42.757795] [df121f40] [c000fd48] ret_from_syscall+0x0/0x3c > > Which leads us to > > ~/git/linux-2.6/drivers/char/random.c, where we can find this code: > > inode->i_mtime = current_fs_time(inode->i_sb); > mark_inode_dirty(inode); > return (ssize_t)count; > > which is the reason for the assertion and for the further budgeting > screw-up. > > The thing is that UBIFS has to allocate budget every-time a clean inode > is made dirty. But the 'random' driver bypasses UBIFS budget allocation, > and instead, changes mtime directly and marks the inode as dirty > directly. > > The driver should instead call the ->setattr() method of the inode, > which should do the right thing. IOW, something like this is needed: > > diff --git a/drivers/char/random.c b/drivers/char/random.c > index 8258982..f911781 100644 > --- a/drivers/char/random.c > +++ b/drivers/char/random.c > @@ -1108,6 +1108,7 @@ static ssize_t random_write(struct file *file, > const char __user *buffer, > { > size_t ret; > struct inode *inode = file->f_path.dentry->d_inode; > + struct iattr; > > ret = write_pool(&blocking_pool, buffer, count); > if (ret) > @@ -1116,8 +1117,11 @@ static ssize_t random_write(struct file *file, > const char __user *buffer, > if (ret) > return ret; > > - inode->i_mtime = current_fs_time(inode->i_sb); > - mark_inode_dirty(inode); > + iattr->i_mtime = current_fs_time(inode->i_sb); > + iattr->ia_valid = ATTR_ATIME; > + ret = inode_setattr(inode, &attr); > + if (ret) > + return ret; > return (ssize_t)count; > } > > Note - I did not even compile-test this. Would you try that please :-) Hmm. I'd just as soon drop it entirely. Here's a patch. Herbert, you want to send this through your crypto tree? random: drop weird m_time/a_time manipulation No other driver does anything remotely like this that I know of except for the tty drivers, and I can't see any reason for random/urandom to do it. In fact, it's a (trivial, harmless) timing information leak. And obviously, it generates power- and flash-cycle wasting I/O, especially if combined with something like hwrngd. Also, it breaks ubifs's expectations. Signed-off-by: Matt Mackall diff -r 29db0c391ce8 drivers/char/random.c --- a/drivers/char/random.c Sun Jan 17 11:01:16 2010 -0800 +++ b/drivers/char/random.c Mon Jan 25 23:32:00 2010 -0600 @@ -1051,12 +1051,6 @@ /* like a named pipe */ } - /* - * If we gave the user some bytes, update the access time. - */ - if (count) - file_accessed(file); - return (count ? count : retval); } @@ -1116,8 +1110,6 @@ if (ret) return ret; - inode->i_mtime = current_fs_time(inode->i_sb); - mark_inode_dirty(inode); return (ssize_t)count; } -- http://selenic.com : development and support for Mercurial and Linux -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/