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Message-id: <00ff01cf7975$a5f5fd10$f1e1f730$@samsung.com>
Date: Tue, 27 May 2014 14:32:57 +0800
From: Chao Yu <chao2.yu@...sung.com>
To: 'Changman Lee' <cm224.lee@...sung.com>
Cc: 'Jaegeuk Kim' <jaegeuk.kim@...sung.com>,
linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net
Subject: RE: [f2fs-dev] [PATCH v2] f2fs: avoid crash when trace
f2fs_submit_page_mbio event in ra_sum_pages
Hi changman,
> -----Original Message-----
> From: Changman Lee [mailto:cm224.lee@...sung.com]
> Sent: Tuesday, May 27, 2014 9:25 AM
> To: Chao Yu
> Cc: Jaegeuk Kim; linux-fsdevel@...r.kernel.org; linux-kernel@...r.kernel.org;
> linux-f2fs-devel@...ts.sourceforge.net
> Subject: Re: [f2fs-dev] [PATCH v2] f2fs: avoid crash when trace f2fs_submit_page_mbio event
> in ra_sum_pages
>
> Hi, Chao
>
> Could you think about following once.
> move node_inode in front of build_segment_manager, then use node_inode
> instead of bd_inode.
Jaegeuk and I discussed this solution previously in
[PATCH 3/3 V3] f2fs: introduce f2fs_cache_node_page() to add page into node_inode cache
You can see it from this url:
http://sourceforge.net/p/linux-f2fs/mailman/linux-f2fs-devel/?viewmonth=201312&page=5
And it seems not easy to change order of build_*_manager and make node_inode,
because there are dependency between them.
>
> On Tue, May 27, 2014 at 08:41:07AM +0800, Chao Yu wrote:
> > 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.
> >
> > Changes from V1
> > o remove redundant code in ra_sum_pages() suggested by Jaegeuk Kim.
> >
> > Call Trace:
> > [<f1031630>] ? ftrace_raw_event_f2fs_write_checkpoint+0x80/0x80 [f2fs]
> > [<f10377bb>] f2fs_submit_page_mbio+0x1cb/0x200 [f2fs]
> > [<f103c5da>] restore_node_summary+0x13a/0x280 [f2fs]
> > [<f103e22d>] build_curseg+0x2bd/0x620 [f2fs]
> > [<f104043b>] build_segment_manager+0x1cb/0x920 [f2fs]
> > [<f1032c85>] f2fs_fill_super+0x535/0x8e0 [f2fs]
> > [<c115b66a>] mount_bdev+0x16a/0x1a0
> > [<f102f63f>] f2fs_mount+0x1f/0x30 [f2fs]
> > [<c115c096>] mount_fs+0x36/0x170
> > [<c1173635>] vfs_kern_mount+0x55/0xe0
> > [<c1175388>] do_mount+0x1e8/0x900
> > [<c1175d72>] SyS_mount+0x82/0xc0
> > [<c16059cc>] sysenter_do_call+0x12/0x22
> >
> > Suggested-by: Jaegeuk Kim <jaegeuk.kim@...sung.com>
> > Signed-off-by: Chao Yu <chao2.yu@...sung.com>
> > ---
> > fs/f2fs/node.c | 52 ++++++++++++++++++++++++----------------------------
> > 1 file changed, 24 insertions(+), 28 deletions(-)
> >
> > diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> > index 3d60d3d..02a59e9 100644
> > --- a/fs/f2fs/node.c
> > +++ b/fs/f2fs/node.c
> > @@ -1658,35 +1658,29 @@ 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;
> > - int page_idx = start;
> > + struct inode *inode = sbi->sb->s_bdev->bd_inode;
> > + struct address_space *mapping = inode->i_mapping;
> > + int i, page_idx = start;
> > struct f2fs_io_info fio = {
> > .type = META,
> > .rw = READ_SYNC | REQ_META | REQ_PRIO
> > };
> >
> > - for (; page_idx < start + nrpages; page_idx++) {
> > - /* alloc temporal page for read node summary info*/
> > - page = alloc_page(GFP_F2FS_ZERO);
> > - if (!page)
> > + for (i = 0; page_idx < start + nrpages; page_idx++, i++) {
> > + /* alloc page in bd_inode for reading node summary info */
> > + pages[i] = grab_cache_page(mapping, page_idx);
> > + if (!pages[i])
> > break;
> > -
> > - lock_page(page);
> > - page->index = page_idx;
> > - list_add_tail(&page->lru, pages);
> > + f2fs_submit_page_mbio(sbi, pages[i], page_idx, &fio);
> > }
> >
> > - list_for_each_entry(page, pages, lru)
> > - f2fs_submit_page_mbio(sbi, page, page->index, &fio);
> > -
> > f2fs_submit_merged_bio(sbi, META, READ);
> > -
> > - return page_idx - start;
> > + return i;
> > }
> >
> > int restore_node_summary(struct f2fs_sb_info *sbi,
> > @@ -1694,11 +1688,11 @@ 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, idx, last_offset, nrpages, err = 0;
> >
> > /* scan the node segment */
> > last_offset = sbi->blocks_per_seg;
> > @@ -1709,29 +1703,31 @@ 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 (idx = 0; idx < nrpages; idx++) {
> > if (err)
> > goto skip;
> >
> > - lock_page(page);
> > - if (unlikely(!PageUptodate(page))) {
> > + lock_page(pages[idx]);
> > + if (unlikely(!PageUptodate(pages[idx]))) {
> > err = -EIO;
> > } else {
> > - rn = F2FS_NODE(page);
> > + rn = F2FS_NODE(pages[idx]);
> > sum_entry->nid = rn->footer.nid;
> > sum_entry->version = 0;
> > sum_entry->ofs_in_node = 0;
> > sum_entry++;
> > }
> > - unlock_page(page);
> > + unlock_page(pages[idx]);
> > skip:
> > - list_del(&page->lru);
> > - __free_pages(page, 0);
> > + page_cache_release(pages[idx]);
> > }
> > +
> > + invalidate_mapping_pages(inode->i_mapping, addr,
> > + addr + nrpages);
> > }
> > return err;
> > }
> > --
> > 1.7.9.5
> >
> >
> >
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> > _______________________________________________
> > Linux-f2fs-devel mailing list
> > Linux-f2fs-devel@...ts.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
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