[PATCH 2/2] 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>
---
 fs/f2fs/checkpoint.c |  2 +-
 fs/f2fs/gc.c         |  2 ++
 fs/f2fs/node.c       | 12 ++++++++++--
 fs/f2fs/recovery.c   |  2 ++
 fs/f2fs/segment.c    |  3 +++
 5 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 01e0d8f5bbbe..6ce3cb6502dd 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -121,7 +121,7 @@ struct page *f2fs_get_meta_page_nofail(struct f2fs_sb_info *sbi, pgoff_t index)
 			goto retry;
 
 		f2fs_stop_checkpoint(sbi, false);
-		f2fs_bug_on(sbi, 1);
+		return NULL;
 	}
 
 	return page;
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 4bcc8a59fdef..d049865887cf 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1070,6 +1070,8 @@ 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 (!sum_page)
+			return -EIO;
 		unlock_page(sum_page);
 	}
 
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index fa2381c0bc47..b3595522c35b 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 (!src_page)
+		return NULL;
 	dst_page = f2fs_grab_meta_page(sbi, dst_off);
 	f2fs_bug_on(sbi, PageDirty(src_page));
 
@@ -2265,8 +2267,12 @@ 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 (page) {
+				ret = scan_nat_page(sbi, page, nid);
+				f2fs_put_page(page, 1);
+			} else {
+				ret = -EIO;
+			}
 
 			if (ret) {
 				up_read(&nm_i->nat_tree_lock);
@@ -2724,6 +2730,8 @@ 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 (!page)
+			return;
 		nat_blk = page_address(page);
 		f2fs_bug_on(sbi, !nat_blk);
 	}
diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index 56d34193a74b..a3dce16bfd6c 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 (!sum_page)
+		return -EIO;
 	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..cfc9eb492da1 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, !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 (!page)
+				return err;
 			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