[PATCH] f2fs: fix to check continuousness in f2fs_sync_meta_pages() correctly

[Chao Yu <chao@kernel.org>]

From: Chao Yu <chao@kernel.org>

In f2fs_sync_meta_pages(), whenever i becomes zero inside while loop,
below check may be skipped, it failed to check the continuousness:

	if (nr_to_write != LONG_MAX && i != 0 &&
		folio->index != prev +
		folio_nr_pages(fbatch.folios[i-1])) {

Cc: stable@kernel.org
Fixes: 580e7a492608 ("f2fs: convert f2fs_sync_meta_pages() to use filemap_get_folios_tag()")
Signed-off-by: Chao Yu <chao@kernel.org>
---
 fs/f2fs/checkpoint.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 7b89bb838946..2e5e0ee5feb2 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -606,7 +606,7 @@ void f2fs_write_meta_caches(struct f2fs_sb_info *sbi)
 long f2fs_sync_meta_caches(struct f2fs_sb_info *sbi, long nr_to_write,
 				bool sync, enum iostat_type io_type)
 {
-	pgoff_t index = 0, prev = ULONG_MAX;
+	pgoff_t index = 0, next = ULONG_MAX;
 	struct f2fs_cached_block *entries[F2FS_ONSTACK_CACHES];
 	long nwritten = 0;
 	int nr;
@@ -629,8 +629,8 @@ long f2fs_sync_meta_caches(struct f2fs_sb_info *sbi, long nr_to_write,
 				goto stop;
 			}
 
-			if (background && i != 0 &&
-					entry->index != prev + 1) {
+			if (background && next != ULONG_MAX &&
+					entry->index != next) {
 				f2fs_cache_gang_release(entries, nr);
 				goto stop;
 			}
@@ -657,7 +657,7 @@ long f2fs_sync_meta_caches(struct f2fs_sb_info *sbi, long nr_to_write,
 				break;
 			}
 			nwritten++;
-			prev = entry->index;
+			next = entry->index + 1;
 			if (unlikely(nwritten >= nr_to_write))
 				break;
 		}
-- 
2.49.0