From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Subject: Re: [patch 12/41] fs: introduce write_begin, write_end, and perform_write aops Date: Thu, 31 May 2007 06:43:27 +0200 Message-ID: <20070531044327.GD20107@wotan.suse.de> References: <20070524052844.860329000@suse.de> <20070524053155.065366000@linux.local0.net> <20070530213035.d7b6e3e0.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org, Mark Fasheh , Linux Memory Management To: Andrew Morton Return-path: Received: from cantor.suse.de ([195.135.220.2]:55440 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753366AbXEaEnd (ORCPT ); Thu, 31 May 2007 00:43:33 -0400 Content-Disposition: inline In-Reply-To: <20070530213035.d7b6e3e0.akpm@linux-foundation.org> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Wed, May 30, 2007 at 09:30:35PM -0700, Andrew Morton wrote: > On Fri, 25 May 2007 22:21:56 +1000 npiggin@suse.de wrote: > > > These are intended to replace prepare_write and commit_write with more > > flexible alternatives that are also able to avoid the buffered write > > deadlock problems efficiently (which prepare_write is unable to do). > > It doesn't like LTP's vmsplice01: > > ------------[ cut here ]------------ > kernel BUG at fs/buffer.c:1829! > invalid opcode: 0000 [#1] > SMP > Modules linked in: > CPU: 0 > EIP: 0060:[] Not tainted VLI > EFLAGS: 00010206 (2.6.22-rc3-mm1 #1) > EIP is at __block_prepare_write+0x348/0x360 > eax: 4000081d ebx: c176f10c ecx: 000001f0 edx: c176f10c > esi: df877670 edi: deeae3f0 ebp: de89fdc0 esp: de89fd60 > ds: 007b es: 007b fs: 00d8 gs: 0033 ss: 0068 > Process vmsplice01 (pid: 15759, ti=de89e000 task=c3ac1100 task.ti=de89e000) > Stack: c0140083 de89fd7c 00000046 00000000 c2fffe20 000001f0 c176f10c deeae3f0 > c017c982 c01ee9b7 df877668 c01ee9b7 df877670 c345f300 df877684 de89fdcc > c01ee9eb c176f10c de89fdc4 c015c7ee deeae504 c176f10c df877670 deeae3f0 > Call Trace: > [] show_trace_log_lvl+0x1a/0x30 > [] show_stack_log_lvl+0xa8/0xe0 > [] show_registers+0x1e9/0x2f0 > [] die+0x10f/0x240 > [] do_trap+0x91/0xc0 > [] do_invalid_op+0x89/0xa0 > [] error_code+0x72/0x78 > [] block_write_begin+0x49/0xd0 > [] ext3_write_begin+0xb7/0x190 > [] pagecache_write_begin+0x4f/0x150 > [] pipe_to_file+0x8b/0x140 > [] __splice_from_pipe+0x70/0x250 > [] splice_from_pipe+0x48/0x70 > [] generic_file_splice_write+0x54/0x100 > [] do_splice_from+0x5f/0x80 > [] sys_splice+0x164/0x200 > [] sysenter_past_esp+0x5f/0x99 > ======================= > INFO: lockdep is turned off. > Code: 49 c0 89 44 24 0c 89 7c 24 08 89 5c 24 04 c7 04 24 ac 2a 49 c0 e8 e9 ff f7 ff e8 b4 21 f6 ff 8b 4d f0 e9 a6 fe ff ff 0f 0b eb fe <0f> 0b eb fe 8d 74 26 00 0f 0b eb fe 0f 0b eb fe 90 8d b4 26 00 > EIP: [] __block_prepare_write+0x348/0x360 SS:ESP 0068:de89fd60 > > > That's > > BUG_ON(to > PAGE_CACHE_SIZE); Thanks. Hmm, sorry I didn't test splice much. Does this fix it? --- Index: linux-2.6/fs/splice.c =================================================================== --- linux-2.6.orig/fs/splice.c +++ linux-2.6/fs/splice.c @@ -570,7 +570,7 @@ static int pipe_to_file(struct pipe_inod if (this_len + offset > PAGE_CACHE_SIZE) this_len = PAGE_CACHE_SIZE - offset; - ret = pagecache_write_begin(file, mapping, sd->pos, sd->len, + ret = pagecache_write_begin(file, mapping, sd->pos, this_len, AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); if (unlikely(ret)) goto out; @@ -587,7 +587,7 @@ static int pipe_to_file(struct pipe_inod buf->ops->unmap(pipe, buf, src); } - ret = pagecache_write_end(file, mapping, sd->pos, sd->len, sd->len, page, fsdata); + ret = pagecache_write_end(file, mapping, sd->pos, this_len, this_len, page, fsdata); out: