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Date: Tue, 27 May 2014 10:25:05 +0900
From: Changman Lee <cm224.lee@...sung.com>
To: Chao Yu <chao2.yu@...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, Chao
Could you think about following once.
move node_inode in front of build_segment_manager, then use node_inode
instead of bd_inode.
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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