3af2d3a8c5
For selinux or encryption scenarios, UBIFS could become inconsistent
while creating new files in powercut case. Encryption/selinux related
xattrs will be created before creating file dentry, which makes creation
process is not atomic, details are shown as:
Encryption case:
ubifs_create
ubifs_new_inode
fscrypt_set_context
ubifs_xattr_set
create_xattr
ubifs_jnl_update // Disk: xentry xinode inode(LAST_OF_NODE_GROUP)
>> power cut <<
ubifs_jnl_update // Disk: dentry inode parent_inode(LAST_OF_NODE_GROUP)
Selinux case:
ubifs_create
ubifs_new_inode
ubifs_init_security
security_inode_init_security
ubifs_xattr_set
create_xattr
ubifs_jnl_update // Disk: xentry xinode inode(LAST_OF_NODE_GROUP)
>> power cut <<
ubifs_jnl_update // Disk: dentry inode parent_inode(LAST_OF_NODE_GROUP)
Above process will make chk_fs failed in next mounting:
UBIFS error (ubi0:0 pid 7995): dbg_check_filesystem [ubifs]: inode 66
nlink is 1, but calculated nlink is 0
Fix it by allocating orphan inode for each non-xattr file creation, then
removing orphan list in journal writing process, which ensures that both
xattr and dentry be effective in atomic when powercut happens.
Fixes: d7f0b70d30ff ("UBIFS: Add security.* XATTR support for the UBIFS")
Fixes: d475a507457b ("ubifs: Add skeleton for fscrypto")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=218309
Suggested-by: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.