f2fs: fix to add refcount once page is tagged PG_private
As Gao Xiang reported in bugzilla:
https://bugzilla.kernel.org/show_bug.cgi?id=202749
f2fs may skip pageout() due to incorrect page reference count.
The problem here is that MM defined the rule [1] very clearly that
once page was set with PG_private flag, we should increment the
refcount in that page, also main flows like pageout(), migrate_page()
will assume there is one additional page reference count if
page_has_private() returns true.
But currently, f2fs won't add/del refcount when changing PG_private
flag. Anyway, f2fs should follow MM's rule to make MM's related flows
running as expected.
[1] https://lore.kernel.org/lkml/2b19b3c4-2bc4-15fa-15cc-27a13e5c7af1@aol.com/
Reported-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index e39ca80..93e9d42 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1963,7 +1963,7 @@
if (!PageDirty(page)) {
__set_page_dirty_nobuffers(page);
inc_page_count(F2FS_P_SB(page), F2FS_DIRTY_NODES);
- SetPagePrivate(page);
+ f2fs_set_page_private(page, 0);
f2fs_trace_pid(page);
return 1;
}