f2fs: get victim segment again after new cp

Previous selected segment may become free after write_checkpoint,
if we do garbage collect on this segment, and then new_curseg happen
to reuse it, it may cause f2fs_bug_on as below.

	panic+0x154/0x29c
	do_garbage_collect+0x15c/0xaf4
	f2fs_gc+0x2dc/0x444
	f2fs_balance_fs.part.22+0xcc/0x14c
	f2fs_balance_fs+0x28/0x34
	f2fs_map_blocks+0x5ec/0x790
	f2fs_preallocate_blocks+0xe0/0x100
	f2fs_file_write_iter+0x64/0x11c
	new_sync_write+0xac/0x11c
	vfs_write+0x144/0x1e4
	SyS_write+0x60/0xc0

Here, maybe we check sit and ssa type during reset_curseg. So, we check
segment is stale or not, and select a new victim to avoid this.

Signed-off-by: Yunlei He <heyunlei@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index de6c41c32c6295c636e5ad1eeaf1c381560db48a..06cfb94cc3db22a142c0b3c2346911d4cb7a001c 100644 (file)
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -908,10 +908,13 @@ gc_more:
                 * enough free sections, we should flush dent/node blocks and do
                 * garbage collections.
                 */
-               if (__get_victim(sbi, &segno, gc_type) || prefree_segments(sbi))
+               if (__get_victim(sbi, &segno, gc_type) ||
+                                               prefree_segments(sbi)) {
                        write_checkpoint(sbi, &cpc);
-               else if (has_not_enough_free_secs(sbi, 0))
+                       segno = NULL_SEGNO;
+               } else if (has_not_enough_free_secs(sbi, 0)) {
                        write_checkpoint(sbi, &cpc);
+               }
        }
 
        if (segno == NULL_SEGNO && !__get_victim(sbi, &segno, gc_type))