From: Zhihao Cheng <chengzhihao1@xxxxxxxxxx>
[ Upstream commit 944e096aa24071d3fe22822f6249d3ae309e39ea ]
Dirty znodes will be written on flash in committing process with
following states:
process A | znode state
------------------------------------------------------
do_commit | DIRTY_ZNODE
ubifs_tnc_start_commit | DIRTY_ZNODE
get_znodes_to_commit | DIRTY_ZNODE | COW_ZNODE
layout_commit | DIRTY_ZNODE | COW_ZNODE
fill_gap | 0
write master | 0 or OBSOLETE_ZNODE
process B | znode state
------------------------------------------------------
do_commit | DIRTY_ZNODE[1]
ubifs_tnc_start_commit | DIRTY_ZNODE
get_znodes_to_commit | DIRTY_ZNODE | COW_ZNODE
ubifs_tnc_end_commit | DIRTY_ZNODE | COW_ZNODE
write_index | 0
write master | 0 or OBSOLETE_ZNODE[2] or
| DIRTY_ZNODE[3]
[1] znode is dirtied without concurrent committing process
[2] znode is copied up (re-dirtied by other process) before cleaned
up in committing process
[3] znode is re-dirtied after cleaned up in committing process
Currently, the clean znode count is updated in free_obsolete_znodes(),
which is called only in normal path. If do_commit failed, clean znode
count won't be updated, which triggers a failure ubifs assertion[4] in
ubifs_tnc_close():
ubifs_assert_failed [ubifs]: UBIFS assert failed: freed == n
[4] Commit 380347e9ca7682 ("UBIFS: Add an assertion for clean_zn_cnt").
Fix it by re-statisticing cleaned znode count in tnc_destroy_cnext().
Fetch a reproducer in [Link].
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216704
Fixes: 1e51764a3c2a ("UBIFS: add new flash file system")
Signed-off-by: Zhihao Cheng <chengzhihao1@xxxxxxxxxx>
Signed-off-by: Richard Weinberger <richard@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/ubifs/tnc.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/fs/ubifs/tnc.c b/fs/ubifs/tnc.c
index 894f1ab14616e..7c36b66774301 100644
--- a/fs/ubifs/tnc.c
+++ b/fs/ubifs/tnc.c
@@ -3053,6 +3053,21 @@ static void tnc_destroy_cnext(struct ubifs_info *c)
cnext = cnext->cnext;
if (ubifs_zn_obsolete(znode))
kfree(znode);
+ else if (!ubifs_zn_cow(znode)) {
+ /*
+ * Don't forget to update clean znode count after
+ * committing failed, because ubifs will check this
+ * count while closing tnc. Non-obsolete znode could
+ * be re-dirtied during committing process, so dirty
+ * flag is untrustable. The flag 'COW_ZNODE' is set
+ * for each dirty znode before committing, and it is
+ * cleared as long as the znode become clean, so we
+ * can statistic clean znode count according to this
+ * flag.
+ */
+ atomic_long_inc(&c->clean_zn_cnt);
+ atomic_long_inc(&ubifs_clean_zn_cnt);
+ }
} while (cnext && cnext != c->cnext);
}
--
2.39.2
