Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755098Ab2K2WGZ (ORCPT ); Thu, 29 Nov 2012 17:06:25 -0500 Received: from mail-vb0-f46.google.com ([209.85.212.46]:55588 "EHLO mail-vb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754545Ab2K2WGX (ORCPT ); Thu, 29 Nov 2012 17:06:23 -0500 MIME-Version: 1.0 In-Reply-To: <20121129213316.GU4939@ZenIV.linux.org.uk> References: <20121129213316.GU4939@ZenIV.linux.org.uk> Date: Thu, 29 Nov 2012 14:06:22 -0800 Message-ID: Subject: Re: Regression with initramfs and nfsroot (appears to be in the dcache) From: Patrick McLean To: Al Viro Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5942 Lines: 110 On Thu, Nov 29, 2012 at 1:33 PM, Al Viro wrote: > On Thu, Nov 29, 2012 at 11:16:59AM -0800, Patrick McLean wrote: >> With 3.6-rc1 and up, when using a (dracut) initramfs with a read-only >> nfs root, all accesses to /proc. /sys and /dev return EBUSY. > > See "[PATCH] Revert "__d_unalias() should refuse to move mountpoints" > thread. If you have a convenient reproducer, could you check if > the fixes the breakage? If so, we'll need to look into false negatives > from nfs_same_file() in there... > > diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c > index ce8cb92..55436f5 100644 > --- a/fs/nfs/dir.c > +++ b/fs/nfs/dir.c > @@ -450,7 +450,10 @@ void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry) > nfs_refresh_inode(dentry->d_inode, entry->fattr); > goto out; > } else { > - d_drop(dentry); > + if (d_invalidate(dentry) != 0) { > + WARN_ON(1); > + goto out; > + } > dput(dentry); > } > } I have a trivial reproducer and am happy to help debug in any way that I can. That patch seems to fix the problem, and produces these warnings in dmesg: [ 3.306483] dracut: Switching root [ 4.324378] systemd-udevd[552]: starting version 195 [ 9.254972] ------------[ cut here ]------------ [ 9.254981] WARNING: at fs/nfs/dir.c:454 nfs_readdir_page_filler+0x1cc/0x3a2() [ 9.254983] Hardware name: Bochs [ 9.254984] Modules linked in: [ 9.254989] Pid: 676, comm: ls Not tainted 3.7.0-rc7+ #35 [ 9.254990] Call Trace: [ 9.254999] [] ? warn_slowpath_common+0x76/0x8a [ 9.255002] [] ? nfs_readdir_page_filler+0x1cc/0x3a2 [ 9.255005] [] ? nfs_readdir_xdr_to_array+0x1c0/0x22d [ 9.255009] [] ? nfs_readdir_filler+0x1c/0x6b [ 9.255014] [] ? add_to_page_cache_lru+0x2c/0x36 [ 9.255017] [] ? nfs_readdir_xdr_to_array+0x22d/0x22d [ 9.255020] [] ? do_read_cache_page+0x7d/0x12b [ 9.255025] [] ? sys_ioctl+0x7a/0x7a [ 9.255028] [] ? read_cache_page+0x7/0x10 [ 9.255031] [] ? nfs_readdir+0x12d/0x435 [ 9.255036] [] ? nfs3_xdr_dec_create3res+0xc5/0xc5 [ 9.255039] [] ? sys_ioctl+0x7a/0x7a [ 9.255042] [] ? sys_ioctl+0x7a/0x7a [ 9.255045] [] ? vfs_readdir+0x6c/0xa7 [ 9.255049] [] ? sys_getdents+0x7e/0xdc [ 9.255053] [] ? system_call_fastpath+0x16/0x1b [ 9.255055] ---[ end trace 5e8b5f37fe752ab1 ]--- [ 9.255062] ------------[ cut here ]------------ [ 9.255065] WARNING: at fs/nfs/dir.c:454 nfs_readdir_page_filler+0x1cc/0x3a2() [ 9.255066] Hardware name: Bochs [ 9.255067] Modules linked in: [ 9.255070] Pid: 676, comm: ls Tainted: G W 3.7.0-rc7+ #35 [ 9.255071] Call Trace: [ 9.255075] [] ? warn_slowpath_common+0x76/0x8a [ 9.255077] [] ? nfs_readdir_page_filler+0x1cc/0x3a2 [ 9.255080] [] ? nfs_readdir_xdr_to_array+0x1c0/0x22d [ 9.255083] [] ? nfs_readdir_filler+0x1c/0x6b [ 9.255087] [] ? add_to_page_cache_lru+0x2c/0x36 [ 9.255089] [] ? nfs_readdir_xdr_to_array+0x22d/0x22d [ 9.255093] [] ? do_read_cache_page+0x7d/0x12b [ 9.255096] [] ? sys_ioctl+0x7a/0x7a [ 9.255099] [] ? read_cache_page+0x7/0x10 [ 9.255102] [] ? nfs_readdir+0x12d/0x435 [ 9.255105] [] ? nfs3_xdr_dec_create3res+0xc5/0xc5 [ 9.255109] [] ? sys_ioctl+0x7a/0x7a [ 9.255112] [] ? sys_ioctl+0x7a/0x7a [ 9.255115] [] ? vfs_readdir+0x6c/0xa7 [ 9.255118] [] ? sys_getdents+0x7e/0xdc [ 9.255121] [] ? system_call_fastpath+0x16/0x1b [ 9.255122] ---[ end trace 5e8b5f37fe752ab2 ]--- [ 9.255133] ------------[ cut here ]------------ [ 9.255135] WARNING: at fs/nfs/dir.c:454 nfs_readdir_page_filler+0x1cc/0x3a2() [ 9.255136] Hardware name: Bochs [ 9.255137] Modules linked in: [ 9.255140] Pid: 676, comm: ls Tainted: G W 3.7.0-rc7+ #35 [ 9.255141] Call Trace: [ 9.255144] [] ? warn_slowpath_common+0x76/0x8a [ 9.255147] [] ? nfs_readdir_page_filler+0x1cc/0x3a2 [ 9.255150] [] ? nfs_readdir_xdr_to_array+0x1c0/0x22d [ 9.255153] [] ? nfs_readdir_filler+0x1c/0x6b [ 9.255157] [] ? add_to_page_cache_lru+0x2c/0x36 [ 9.255159] [] ? nfs_readdir_xdr_to_array+0x22d/0x22d [ 9.255162] [] ? do_read_cache_page+0x7d/0x12b [ 9.255166] [] ? sys_ioctl+0x7a/0x7a [ 9.255169] [] ? read_cache_page+0x7/0x10 [ 9.255171] [] ? nfs_readdir+0x12d/0x435 [ 9.255175] [] ? nfs3_xdr_dec_create3res+0xc5/0xc5 [ 9.255178] [] ? sys_ioctl+0x7a/0x7a [ 9.255181] [] ? sys_ioctl+0x7a/0x7a [ 9.255184] [] ? vfs_readdir+0x6c/0xa7 [ 9.255188] [] ? sys_getdents+0x7e/0xdc [ 9.255190] [] ? system_call_fastpath+0x16/0x1b [ 9.255192] ---[ end trace 5e8b5f37fe752ab3 ]--- -- 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/