From: Zhihao Cheng chengzhihao1@huawei.com
[ Upstream commit 25fce616a61fc2f1821e4a9ce212d0e064707093 ]
If target inode is a special file (eg. block/char device) with nlink count greater than 1, the inode with ui->data will be re-written on disk. However, UBIFS losts target inode's data_len while doing space budget. Bad space budget may let make_reservation() return with -ENOSPC, which could turn ubifs to read-only mode in do_writepage() process.
Fetch a reproducer in [Link].
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216494 Fixes: 1e51764a3c2ac0 ("UBIFS: add new flash file system") Signed-off-by: Zhihao Cheng chengzhihao1@huawei.com Signed-off-by: Richard Weinberger richard@nod.at Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ubifs/dir.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c index 89c5c2abc0faf..3b93b14e00412 100644 --- a/fs/ubifs/dir.c +++ b/fs/ubifs/dir.c @@ -1309,9 +1309,13 @@ static int do_rename(struct inode *old_dir, struct dentry *old_dentry, old_dentry, old_inode->i_ino, old_dir->i_ino, new_dentry, new_dir->i_ino, flags);
- if (unlink) + if (unlink) { ubifs_assert(c, inode_is_locked(new_inode));
+ /* Budget for old inode's data when its nlink > 1. */ + req.dirtied_ino_d = ALIGN(ubifs_inode(new_inode)->data_len, 8); + } + if (unlink && is_dir) { err = ubifs_check_dir_empty(new_inode); if (err)