Commit fe94793e authored Jul 22, 2016 by Yunlei He Committed by Jaegeuk Kim Jul 22, 2016

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>

parent 6f3ec995

fs/f2fs/gc.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -908,11 +908,14 @@ 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))
		goto stop;

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