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

[Jaegeuk Kim <jaegeuk@kernel.org>]

This patch avoids BUG_ON when f2fs_get_meta_page_nofail got EIO during
xfstests/generic/475.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
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;
 			}
 		}
 
@@ -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);
-- 
2.17.0.441.gb46fe60e1d-goog