Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762844AbXHXHpX (ORCPT ); Fri, 24 Aug 2007 03:45:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754958AbXHXHpK (ORCPT ); Fri, 24 Aug 2007 03:45:10 -0400 Received: from tama5.ecl.ntt.co.jp ([129.60.39.102]:52377 "EHLO tama5.ecl.ntt.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752683AbXHXHpI (ORCPT ); Fri, 24 Aug 2007 03:45:08 -0400 Message-Id: <200708240743.AA00249@paprika.lab.ntt.co.jp> From: Ryusuke Konishi Date: Fri, 24 Aug 2007 16:43:46 +0900 To: trond.myklebust@fys.uio.no Cc: nfs@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: [BUG] problem with nfs_invaildate_page MIME-Version: 1.0 X-Mailer: AL-Mail32 Version 1.13 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4486 Lines: 112 Hi, I got the following BUG in nfs_inode_add_request() when I was using eCryptfs on NFS. (Don't ask me why I was doing that) ------------[ cut here ]------------ kernel BUG at fs/nfs/write.c:387! invalid opcode: 0000 [#1] PREEMPT SMP Modules linked in: cbc md5 aes ecb blkcipher cryptomgr crypto_algapi ecryptfs nfs iscsi_tcp libiscsi scsi_transport_iscsi nfsd exportfs lockd nfs_acl sunrpc nbd md_mod dm_snapshot dm_mirror dm_mod video output CPU: 5 EIP: 0060:[] Not tainted VLI EFLAGS: 00010246 (2.6.23-rc3 #5) EIP is at nfs_writepage_setup+0xc8/0x305 [nfs] eax: ffffffef ebx: ffffffef ecx: 00000000 edx: f776a6c8 esi: f776a700 edi: f3392680 ebp: f6489c04 esp: f6489bc4 ds: 007b es: 007b fs: 00d8 gs: 0033 ss: 0068 Process dd (pid: 4260, ti=f6488000 task=f5719500 task.ti=f6488000) Stack: 00000000 00001000 dd751a4f 730e4905 00000000 c404e0c0 f5a86a80 f33927e4 f3392774 00000000 f6489bf4 c029e298 00000000 f6812780 00000000 c404e0c0 f6489c44 f9011b8c 00001000 00001000 00000010 fff2b000 f6489d08 00000246 Call Trace: [] show_trace_log_lvl+0x1a/0x2f [] show_stack_log_lvl+0x9d/0xa5 [] show_registers+0x1f1/0x332 [] die+0x11b/0x250 [] do_trap+0x8a/0xa3 [] do_invalid_op+0x88/0x92 [] error_code+0x72/0x78 [] nfs_updatepage+0x14d/0x1b3 [nfs] [] nfs_commit_write+0x29/0x39 [nfs] [] ecryptfs_commit_lower_page+0x26/0x6b [ecryptfs] [] ecryptfs_write_out_page+0x28/0x73 [ecryptfs] [] ecryptfs_encrypt_page+0x3a4/0x419 [ecryptfs] [] ecryptfs_commit_write+0x1ba/0x31f [ecryptfs] [] generic_file_buffered_write+0x3a6/0x54e [] __generic_file_aio_write_nolock+0x440/0x493 [] generic_file_aio_write+0x56/0xb4 [] do_sync_write+0xc5/0x102 [] vfs_write+0xaf/0x138 [] sys_write+0x3d/0x61 [] syscall_call+0x7/0xb ======================= Code: 00 00 00 f0 0f ba 6e 28 00 19 c0 8b 7d e0 81 ef f4 00 00 00 8b 56 14 8b 45 e0 83 e8 1c 89 f1 e8 50 db 29 c7 89 c3 83 f8 ef 75 04 <0f> 0b eb fe 85 c0 75 4e 83 bf e8 00 00 00 00 75 10 8b 45 e0 e8 EIP: [] nfs_writepage_setup+0xc8/0x305 [nfs] SS:ESP 0068:f6489bc4 As you may have guessed, the BUG shows a collision of nfs_page in a nfs page tree. That is, there is a case that nfs_page remains even if the requested page is removed from page cache. static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req) { struct nfs_inode *nfsi = NFS_I(inode); int error; error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req); BUG_ON(error == -EEXIST); ... } By some tests, it turned out to be a discordance between nfs_invalidate_page() and truncate_inode_pages() in recent kernels. In kernel 2.6.20, truncate_complete_page() was changed to clear dirty flag from the removing page just before calling a_ops->invalidatepage(). As a result, nfs_wb_page_priority(), which is called from nfs_invalidate_page(), get to skip nfs_writepage_locked() that starts to write dirty pages. int nfs_wb_page_priority(struct inode *inode, struct page *page, int how) { ... if (clear_page_dirty_for_io(page)) { ret = nfs_writepage_locked(page, &wbc); if (ret < 0) goto out; } if (!PagePrivate(page)) return 0; ret = nfs_sync_mapping_wait(page->mapping, &wbc, how); ... } Since nfs_sync_mapping_wait() does not care for non-dirty, unwritten, and uncommitted pages, their nfs_page get into orphans. It seems to need some sort of change to handle unwritten non-dirty pages. For reference, I will show the way to reproduce the BUG using eCryptfs below. I tried other way, but I couldn't find simpler way not requiring eCryptfs so far. # mount -t nfs server:/pub /nfs # mount -t ecryptfs -o cipher=aes,ecryptfs_key_bytes=16 /nfs /secret # dd if=/dev/zero of=/secret/aaa bs=4096 count=1 # dd if=/dev/zero of=/secret/aaa bs=4096 count=1 These procedures do truncate an unwritten NFS page. Note that overwritting without use of eCryptfs doesn't reproduce the problem because it calls nfs_setattr() and forces the pages to be written back. Cheers, Ryusuke Konishi - 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/