From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751521AbaEZGPY (ORCPT ); Mon, 26 May 2014 02:15:24 -0400 Received: from mailout4.samsung.com ([203.254.224.34]:30136 "EHLO mailout4.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751185AbaEZGPW convert rfc822-to-8bit (ORCPT ); Mon, 26 May 2014 02:15:22 -0400 X-AuditID: cbfee61a-b7fef6d00000200b-9d-5382dbf7e978 From: Chao Yu To: "'Jaegeuk Kim'" Cc: "'Jaegeuk Kim'" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net References: <005801cf70e7$66cb0090$346101b0$@samsung.com> <1400643406.12240.6.camel@kjgkr> In-reply-to: <1400643406.12240.6.camel@kjgkr> Subject: RE: [f2fs-dev] [PATCH] f2fs: avoid crash when trace f2fs_submit_page_mbio event in ra_sum_pages Date: Mon, 26 May 2014 14:14:28 +0800 Message-id: <00cb01cf78a9$de935f40$9bba1dc0$@samsung.com> MIME-version: 1.0 Content-type: text/plain; charset=UTF-8 Content-transfer-encoding: 8BIT X-Mailer: Microsoft Outlook 14.0 Thread-index: AQJwOG7Gz2CPmbug9iCDoFZDCoNgZwF/NEK3mgTeD2A= Content-language: zh-cn X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrPLMWRmVeSWpSXmKPExsVy+t9jQd3vt5uCDX7fNra4vusvk8WT9bOY LS4tcrfYs/cki8XlXXPYHFg9Nq3qZPPYveAzk0ffllWMHp83yQWwRHHZpKTmZJalFunbJXBl zF7/jbngoEHFvzlT2BsYW9W6GDk4JARMJDquMXYxcgKZYhIX7q1nA7GFBKYzSqxqE+9i5AKy fzBK/OmaCZZgE1CRWN7xnwnEFhFQk+jdN4UJpIhZYBKjxJKfzSwQ3TES//5cZQaxOQV0Jf5f 38UOYgsLZEnsbr0FZrMIqEqseXwJbDOvgKXE7zsf2CBsQYkfk++BzWEWUJeYNG8RM4StLfHk 3QVWiEsVJHacfc0IcYSVxJKp06BqxCU2HrnFMoFRaBaSUbOQjJqFZNQsJC0LGFlWMYqmFiQX FCel5xrqFSfmFpfmpesl5+duYgRHwzOpHYwrGywOMQpwMCrx8B7wbgoWYk0sK67MPcQowcGs JMJ7IRcoxJuSWFmVWpQfX1Sak1p8iFGag0VJnPdAq3WgkEB6YklqdmpqQWoRTJaJg1OqgZHz /mqnrbPv89SWPn2ryjVDaf4OLWfh6+3TRPVeSLd2dF6flxi0IV/vdoJLhKLMzu17y8Km/93U dpvb9smyjjNXb86w2nUnX/iXk5nFrOfR1lwz5q2NYVmx/vl6qQ4Rces49rtiLDN4dIOW/JSy epOlHRPgrSNy6u/ukGz5SvNHpSmTeL/MjlNiKc5INNRiLipOBABcfPQ6ggIAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Kim, > -----Original Message----- > From: Jaegeuk Kim [mailto:jaegeuk@kernel.org] > Sent: Wednesday, May 21, 2014 11:37 AM > To: Chao Yu > Cc: Jaegeuk Kim; linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org; > linux-f2fs-devel@lists.sourceforge.net > Subject: Re: [f2fs-dev] [PATCH] f2fs: avoid crash when trace f2fs_submit_page_mbio event in > ra_sum_pages > > Hi Chao, > > 2014-05-16 (금), 17:14 +0800, Chao Yu: > > Previously we allocate pages with no mapping in ra_sum_pages(), so we may > > encounter a crash in event trace of f2fs_submit_page_mbio where we access > > mapping data of the page. > > > > We'd better allocate pages in bd_inode mapping and invalidate these pages after > > we restore data from pages. It could avoid crash in above scenario. > > > > Call Trace: > > [] ? ftrace_raw_event_f2fs_write_checkpoint+0x80/0x80 [f2fs] > > [] f2fs_submit_page_mbio+0x1cb/0x200 [f2fs] > > [] restore_node_summary+0x13a/0x280 [f2fs] > > [] build_curseg+0x2bd/0x620 [f2fs] > > [] build_segment_manager+0x1cb/0x920 [f2fs] > > [] f2fs_fill_super+0x535/0x8e0 [f2fs] > > [] mount_bdev+0x16a/0x1a0 > > [] f2fs_mount+0x1f/0x30 [f2fs] > > [] mount_fs+0x36/0x170 > > [] vfs_kern_mount+0x55/0xe0 > > [] do_mount+0x1e8/0x900 > > [] SyS_mount+0x82/0xc0 > > [] sysenter_do_call+0x12/0x22 > > > > Signed-off-by: Chao Yu > > --- > > fs/f2fs/node.c | 49 ++++++++++++++++++++++++++++--------------------- > > 1 file changed, 28 insertions(+), 21 deletions(-) > > > > diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c > > index 3d60d3d..b5cd814 100644 > > --- a/fs/f2fs/node.c > > +++ b/fs/f2fs/node.c > > @@ -1658,13 +1658,16 @@ int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page) > > > > /* > > * ra_sum_pages() merge contiguous pages into one bio and submit. > > - * these pre-readed pages are linked in pages list. > > + * these pre-readed pages are alloced in bd_inode's mapping tree. > > */ > > -static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head *pages, > > +static int ra_sum_pages(struct f2fs_sb_info *sbi, struct page **pages, > > int start, int nrpages) > > { > > struct page *page; > > + struct inode *inode = sbi->sb->s_bdev->bd_inode; > > + struct address_space *mapping = inode->i_mapping; > > int page_idx = start; > > + int alloced, readed; > > struct f2fs_io_info fio = { > > .type = META, > > .rw = READ_SYNC | REQ_META | REQ_PRIO > > @@ -1672,21 +1675,23 @@ static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head > *pages, > > > > for (; page_idx < start + nrpages; page_idx++) { > > /* alloc temporal page for read node summary info*/ > > - page = alloc_page(GFP_F2FS_ZERO); > > + page = grab_cache_page(mapping, page_idx); > > if (!page) > > break; > > - > > - lock_page(page); > > - page->index = page_idx; > > - list_add_tail(&page->lru, pages); > > + page_cache_release(page); > > IMO, we don't need to do like this. > Instead, > for() { > page = grab_cache_page(); > if (!page) > break; > page[page_idx] = page; > f2fs_submit_page_mbio(sbi, page, &fio); > } > f2fs_submit_merged_bio(sbi, META, READ); > return page_idx - start; Agreed, it helps to remove a lot of redundant code here. Thanks! > > Afterwards, in restore_node_summry(), > lock_page() will wait the end_io for read. > ... > f2fs_put_page(pages[index], 1); > > Thanks, > > > } > > > > - list_for_each_entry(page, pages, lru) > > - f2fs_submit_page_mbio(sbi, page, page->index, &fio); > > + alloced = page_idx - start; > > + readed = find_get_pages_contig(mapping, start, alloced, pages); > > + BUG_ON(alloced != readed); > > + > > + for (page_idx = 0; page_idx < readed; page_idx++) > > + f2fs_submit_page_mbio(sbi, pages[page_idx], > > + pages[page_idx]->index, &fio); > > > > f2fs_submit_merged_bio(sbi, META, READ); > > > > - return page_idx - start; > > + return readed; > > } > > > > int restore_node_summary(struct f2fs_sb_info *sbi, > > @@ -1694,11 +1699,11 @@ int restore_node_summary(struct f2fs_sb_info *sbi, > > { > > struct f2fs_node *rn; > > struct f2fs_summary *sum_entry; > > - struct page *page, *tmp; > > + struct inode *inode = sbi->sb->s_bdev->bd_inode; > > block_t addr; > > int bio_blocks = MAX_BIO_BLOCKS(max_hw_blocks(sbi)); > > - int i, last_offset, nrpages, err = 0; > > - LIST_HEAD(page_list); > > + struct page *pages[bio_blocks]; > > + int i, index, last_offset, nrpages, err = 0; > > > > /* scan the node segment */ > > last_offset = sbi->blocks_per_seg; > > @@ -1709,29 +1714,31 @@ int restore_node_summary(struct f2fs_sb_info *sbi, > > nrpages = min(last_offset - i, bio_blocks); > > > > /* read ahead node pages */ > > - nrpages = ra_sum_pages(sbi, &page_list, addr, nrpages); > > + nrpages = ra_sum_pages(sbi, pages, addr, nrpages); > > if (!nrpages) > > return -ENOMEM; > > > > - list_for_each_entry_safe(page, tmp, &page_list, lru) { > > + for (index = 0; index < nrpages; index++) { > > if (err) > > goto skip; > > > > - lock_page(page); > > - if (unlikely(!PageUptodate(page))) { > > + lock_page(pages[index]); > > + if (unlikely(!PageUptodate(pages[index]))) { > > err = -EIO; > > } else { > > - rn = F2FS_NODE(page); > > + rn = F2FS_NODE(pages[index]); > > sum_entry->nid = rn->footer.nid; > > sum_entry->version = 0; > > sum_entry->ofs_in_node = 0; > > sum_entry++; > > } > > - unlock_page(page); > > + unlock_page(pages[index]); > > skip: > > - list_del(&page->lru); > > - __free_pages(page, 0); > > + page_cache_release(pages[index]); > > } > > + > > + invalidate_mapping_pages(inode->i_mapping, addr, > > + addr + nrpages); > > } > > return err; > > } > > -- > Jaegeuk Kim