This is a note to let you know that I've just added the patch titled
ubifs: Re-statistic cleaned znode count if commit failed
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ubifs-re-statistic-cleaned-znode-count-if-commit-fai.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit c0284fa3b6644ac5c0ea5e183bceceabbe3fc86b
Author: Zhihao Cheng <chengzhihao1@xxxxxxxxxx>
Date: Fri Nov 18 17:02:35 2022 +0800
ubifs: Re-statistic cleaned znode count if commit failed
[ 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>
diff --git a/fs/ubifs/tnc.c b/fs/ubifs/tnc.c
index c7828db206bc0..20b70e178c4fa 100644
--- a/fs/ubifs/tnc.c
+++ b/fs/ubifs/tnc.c
@@ -3044,6 +3044,21 @@ 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);
}
