On Mon, May 26, 2014 at 02:26:24PM +0800, Chao Yu wrote: > Hi changman, > > > -----Original Message----- > > From: Changman Lee [mailto:cm224.lee@xxxxxxxxxxx] > > Sent: Friday, May 23, 2014 1:14 PM > > To: Jaegeuk Kim > > Cc: Chao Yu; linux-fsdevel@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > > linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > > Subject: Re: [f2fs-dev] [PATCH] f2fs: avoid crash when trace f2fs_submit_page_mbio event in > > ra_sum_pages > > > > On Wed, May 21, 2014 at 12:36:46PM +0900, Jaegeuk Kim wrote: > > > 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 <chao2.yu@xxxxxxxxxxx> > > > > --- > > > > 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; > > > > How about use sbi->meta_inode instead of bd_inode, then we can do > > caching summary pages for further i/o. > > In my understanding, In ra_sum_pages() we readahead node pages in NODE segment, > then we could padding current summary caching with nid of node page's footer. > So we should not cache this readaheaded pages in meta_inode's mapping. > Do I miss something? > > Regards > Sorry, you're right. Forget about caching. I've confused ra_sum_pages with summary segments. > > > > > > + 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 > > > > > > > > > ------------------------------------------------------------------------------ > > > "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE > > > Instantly run your Selenium tests across 300+ browser/OS combos. > > > Get unparalleled scalability from the best Selenium testing platform available > > > Simple to use. 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