Re: [f2fs-dev] [PATCH 2/2 v2] f2fs: avoid f2fs_bug_on if f2fs_get_meta_page_nofail got EIO

From: Chao Yu
Date: Tue Sep 18 2018 - 21:45:43 EST


On 2018/9/19 1:56, Jaegeuk Kim wrote:
> This patch avoids BUG_ON when f2fs_get_meta_page_nofail got EIO during
> xfstests/generic/475.
>
> Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
> ---
> Change log from v1:
> - propagate errno
> - drop sum_pages
>
> fs/f2fs/checkpoint.c | 10 +++++-----
> fs/f2fs/f2fs.h | 2 +-
> fs/f2fs/gc.c | 9 +++++++++
> fs/f2fs/node.c | 32 ++++++++++++++++++++++++--------
> fs/f2fs/recovery.c | 2 ++
> fs/f2fs/segment.c | 3 +++
> 6 files changed, 44 insertions(+), 14 deletions(-)
>
> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> index 01e0d8f5bbbe..1ddf332ce4b2 100644
> --- a/fs/f2fs/checkpoint.c
> +++ b/fs/f2fs/checkpoint.c
> @@ -119,11 +119,8 @@ struct page *f2fs_get_meta_page_nofail(struct f2fs_sb_info *sbi, pgoff_t index)
> if (PTR_ERR(page) == -EIO &&
> ++count <= DEFAULT_RETRY_IO_COUNT)
> goto retry;
> -
> f2fs_stop_checkpoint(sbi, false);
> - f2fs_bug_on(sbi, 1);
> }
> -
> return page;
> }
>
> @@ -1512,7 +1509,10 @@ int f2fs_write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
> ckpt->checkpoint_ver = cpu_to_le64(++ckpt_ver);
>
> /* write cached NAT/SIT entries to NAT/SIT area */
> - f2fs_flush_nat_entries(sbi, cpc);
> + err = f2fs_flush_nat_entries(sbi, cpc);
> + if (err)
> + goto stop;
> +
> f2fs_flush_sit_entries(sbi, cpc);
>
> /* unlock all the fs_lock[] in do_checkpoint() */
> @@ -1521,7 +1521,7 @@ int f2fs_write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
> f2fs_release_discard_addrs(sbi);
> else
> f2fs_clear_prefree_segments(sbi, cpc);
> -
> +stop:
> unblock_operations(sbi);
> stat_inc_cp_count(sbi->stat_info);
>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index a0c868127a7c..29021dbc8f2a 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -2895,7 +2895,7 @@ int f2fs_recover_xattr_data(struct inode *inode, struct page *page);
> int f2fs_recover_inode_page(struct f2fs_sb_info *sbi, struct page *page);
> int f2fs_restore_node_summary(struct f2fs_sb_info *sbi,
> unsigned int segno, struct f2fs_summary_block *sum);
> -void f2fs_flush_nat_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc);
> +int f2fs_flush_nat_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc);
> int f2fs_build_node_manager(struct f2fs_sb_info *sbi);
> void f2fs_destroy_node_manager(struct f2fs_sb_info *sbi);
> int __init f2fs_create_node_manager_caches(void);
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index 4bcc8a59fdef..c7d14282dbf4 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -1070,6 +1070,15 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
> /* reference all summary page */
> while (segno < end_segno) {
> sum_page = f2fs_get_sum_page(sbi, segno++);
> + if (IS_ERR(sum_page)) {
> + end_segno = segno - 1;
> + for (segno = start_segno; segno < end_segno; segno++) {
> + sum_page = find_get_page(META_MAPPING(sbi),
> + GET_SUM_BLOCK(sbi, segno));
> + f2fs_put_page(sum_page, 0);
> + }
> + return PTR_ERR(sum_page);
> + }
> unlock_page(sum_page);
> }
>
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index fa2381c0bc47..79b6fee354f7 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -126,6 +126,8 @@ static struct page *get_next_nat_page(struct f2fs_sb_info *sbi, nid_t nid)
>
> /* get current nat block page with lock */
> src_page = get_current_nat_page(sbi, nid);
> + if (IS_ERR(src_page))
> + return src_page;
> dst_page = f2fs_grab_meta_page(sbi, dst_off);
> f2fs_bug_on(sbi, PageDirty(src_page));
>
> @@ -2265,15 +2267,19 @@ static int __f2fs_build_free_nids(struct f2fs_sb_info *sbi,
> nm_i->nat_block_bitmap)) {
> struct page *page = get_current_nat_page(sbi, nid);
>
> - ret = scan_nat_page(sbi, page, nid);
> - f2fs_put_page(page, 1);
> + if (IS_ERR(page)) {
> + ret = PTR_ERR(page);
> + } else {
> + ret = scan_nat_page(sbi, page, nid);
> + f2fs_put_page(page, 1);
> + }
>
> if (ret) {
> up_read(&nm_i->nat_tree_lock);
> f2fs_bug_on(sbi, !mount);
> f2fs_msg(sbi->sb, KERN_ERR,
> "NAT is corrupt, run fsck to fix it");
> - return -EINVAL;
> + return ret;
> }

I mean we can propagate the error to caller of f2fs_alloc_nid(), otherwise
we may loop forever in f2fs_alloc_nid() if we fail to load meta page.

f2fs_alloc_nid()

err = f2fs_build_free_nids();
if (err)
return false;
goto retry;

Thanks,

> }
>
> @@ -2700,7 +2706,7 @@ static void __update_nat_bits(struct f2fs_sb_info *sbi, nid_t start_nid,
> __clear_bit_le(nat_index, nm_i->full_nat_bits);
> }
>
> -static void __flush_nat_entry_set(struct f2fs_sb_info *sbi,
> +static int __flush_nat_entry_set(struct f2fs_sb_info *sbi,
> struct nat_entry_set *set, struct cp_control *cpc)
> {
> struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
> @@ -2724,6 +2730,9 @@ static void __flush_nat_entry_set(struct f2fs_sb_info *sbi,
> down_write(&curseg->journal_rwsem);
> } else {
> page = get_next_nat_page(sbi, start_nid);
> + if (IS_ERR(page))
> + return PTR_ERR(page);
> +
> nat_blk = page_address(page);
> f2fs_bug_on(sbi, !nat_blk);
> }
> @@ -2769,12 +2778,13 @@ static void __flush_nat_entry_set(struct f2fs_sb_info *sbi,
> radix_tree_delete(&NM_I(sbi)->nat_set_root, set->set);
> kmem_cache_free(nat_entry_set_slab, set);
> }
> + return 0;
> }
>
> /*
> * This function is called during the checkpointing process.
> */
> -void f2fs_flush_nat_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
> +int f2fs_flush_nat_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
> {
> struct f2fs_nm_info *nm_i = NM_I(sbi);
> struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
> @@ -2784,6 +2794,7 @@ void f2fs_flush_nat_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
> unsigned int found;
> nid_t set_idx = 0;
> LIST_HEAD(sets);
> + int err = 0;
>
> /* during unmount, let's flush nat_bits before checking dirty_nat_cnt */
> if (enabled_nat_bits(sbi, cpc)) {
> @@ -2793,7 +2804,7 @@ void f2fs_flush_nat_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
> }
>
> if (!nm_i->dirty_nat_cnt)
> - return;
> + return 0;
>
> down_write(&nm_i->nat_tree_lock);
>
> @@ -2816,11 +2827,16 @@ void f2fs_flush_nat_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
> }
>
> /* flush dirty nats in nat entry set */
> - list_for_each_entry_safe(set, tmp, &sets, set_list)
> - __flush_nat_entry_set(sbi, set, cpc);
> + list_for_each_entry_safe(set, tmp, &sets, set_list) {
> + err = __flush_nat_entry_set(sbi, set, cpc);
> + if (err)
> + break;
> + }
>
> up_write(&nm_i->nat_tree_lock);
> /* Allow dirty nats by node block allocation in write_begin */
> +
> + return err;
> }
>
> static int __get_nat_bitmaps(struct f2fs_sb_info *sbi)
> diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
> index 56d34193a74b..ba678efe7cad 100644
> --- a/fs/f2fs/recovery.c
> +++ b/fs/f2fs/recovery.c
> @@ -355,6 +355,8 @@ static int check_index_in_prev_nodes(struct f2fs_sb_info *sbi,
> }
>
> sum_page = f2fs_get_sum_page(sbi, segno);
> + if (IS_ERR(sum_page))
> + return PTR_ERR(sum_page);
> sum_node = (struct f2fs_summary_block *)page_address(sum_page);
> sum = sum_node->entries[blkoff];
> f2fs_put_page(sum_page, 1);
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index aa96a371aaf8..ab7386a7e9d3 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -2487,6 +2487,7 @@ static void change_curseg(struct f2fs_sb_info *sbi, int type)
> __next_free_blkoff(sbi, curseg, 0);
>
> sum_page = f2fs_get_sum_page(sbi, new_segno);
> + f2fs_bug_on(sbi, IS_ERR(sum_page));
> sum_node = (struct f2fs_summary_block *)page_address(sum_page);
> memcpy(curseg->sum_blk, sum_node, SUM_ENTRY_SIZE);
> f2fs_put_page(sum_page, 1);
> @@ -3971,6 +3972,8 @@ static int build_sit_entries(struct f2fs_sb_info *sbi)
>
> se = &sit_i->sentries[start];
> page = get_current_sit_page(sbi, start);
> + if (IS_ERR(page))
> + return PTR_ERR(page);
> sit_blk = (struct f2fs_sit_block *)page_address(page);
> sit = sit_blk->entries[SIT_ENTRY_OFFSET(sit_i, start)];
> f2fs_put_page(page, 1);
>