linux-kernel - [PATCH] ubifs: ubifs_jnl_change_xattr: Remove assertion 'nlink

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Date:   Mon, 17 Aug 2020 22:29:09 +0800
From:   Zhihao Cheng <chengzhihao1@...wei.com>
To:     <richard.weinberger@...il.com>, <yi.zhang@...wei.com>
CC:     <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH] ubifs: ubifs_jnl_change_xattr: Remove assertion 'nlink > 0' for host inode

Changing xattr of a temp file will trigger following assertion failed
and make ubifs turn into readonly filesystem:
  ubifs_assert_failed [ubifs]: UBIFS assert failed: host->i_nlink > 0,
  in fs/ubifs/journal.c:1801

Reproducer:
  1. fd = open(__O_TMPFILE)
  2. fsetxattr(fd, key, value2, XATTR_CREATE)
  3. fsetxattr(fd, key, value2, XATTR_REPLACE)

Fix this by removing assertion 'nlink > 0' for host inode.

Reported-by: Chengsong Ke <kechengsong@...wei.com>
Signed-off-by: Zhihao Cheng <chengzhihao1@...wei.com>
---
 fs/ubifs/journal.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/fs/ubifs/journal.c b/fs/ubifs/journal.c
index 4a5b06f8d812..0b9f686d1d42 100644
--- a/fs/ubifs/journal.c
+++ b/fs/ubifs/journal.c
@@ -1798,7 +1798,6 @@ int ubifs_jnl_change_xattr(struct ubifs_info *c, const struct inode *inode,
 	u8 hash[UBIFS_HASH_ARR_SZ];
 
 	dbg_jnl("ino %lu, ino %lu", host->i_ino, inode->i_ino);
-	ubifs_assert(c, host->i_nlink > 0);
 	ubifs_assert(c, inode->i_nlink > 0);
 	ubifs_assert(c, mutex_is_locked(&host_ui->ui_mutex));
 
-- 
2.25.4