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Commit bac4eef6 authored by Chao Yu's avatar Chao Yu Committed by Jaegeuk Kim
Browse files

f2fs: avoid crash when trace f2fs_submit_page_mbio event in ra_sum_pages 



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: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
Signed-off-by: default avatarChao Yu <chao2.yu@samsung.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent bfec07d0

fs/f2fs/node.c

+24 −28
Original line number Diff line number Diff line
@@ -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;

}