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: > [<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 > > Signed-off-by: Chao Yu <[email protected]> > --- > 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;
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
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