No description
Find a file
Hou Tao 27f2a2dcc6 erofs: check the uniqueness of fsid in shared domain in advance
When shared domain is enabled, doing mount twice with the same fsid and
domain_id will trigger sysfs warning as shown below:

 sysfs: cannot create duplicate filename '/fs/erofs/d0,meta.bin'
 CPU: 15 PID: 1051 Comm: mount Not tainted 6.1.0-rc6+ #1
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
 Call Trace:
  <TASK>
  dump_stack_lvl+0x38/0x49
  dump_stack+0x10/0x12
  sysfs_warn_dup.cold+0x17/0x27
  sysfs_create_dir_ns+0xb8/0xd0
  kobject_add_internal+0xb1/0x240
  kobject_init_and_add+0x71/0xa0
  erofs_register_sysfs+0x89/0x110
  erofs_fc_fill_super+0x98c/0xaf0
  vfs_get_super+0x7d/0x100
  get_tree_nodev+0x16/0x20
  erofs_fc_get_tree+0x20/0x30
  vfs_get_tree+0x24/0xb0
  path_mount+0x2fa/0xa90
  do_mount+0x7c/0xa0
  __x64_sys_mount+0x8b/0xe0
  do_syscall_64+0x30/0x60
  entry_SYSCALL_64_after_hwframe+0x46/0xb0

The reason is erofs_fscache_register_cookie() doesn't guarantee the primary
data blob (aka fsid) is unique in the shared domain and
erofs_register_sysfs() invoked by the second mount will fail due to the
duplicated fsid in the shared domain and report warning.

It would be better to check the uniqueness of fsid before doing
erofs_register_sysfs(), so adding a new flags parameter for
erofs_fscache_register_cookie() and doing the uniqueness check if
EROFS_REG_COOKIE_NEED_NOEXIST is enabled.

After the patch, the error in dmesg for the duplicated mount would be:

 erofs: ...: erofs_domain_register_cookie: XX already exists in domain YY

Reviewed-by: Jia Zhu <zhujia.zj@bytedance.com>
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20221125110822.3812942-1-houtao@huaweicloud.com
Fixes: 7d41963759 ("erofs: Support sharing cookies in the same domain")
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2022-12-07 10:53:40 +08:00
arch
block
certs
crypto
Documentation
drivers
fs erofs: check the uniqueness of fsid in shared domain in advance 2022-12-07 10:53:40 +08:00
include
init
io_uring
ipc
kernel
lib
LICENSES
mm
net
rust
samples
scripts
security
sound
tools
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
.rustfmt.toml
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile
README

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 Restructured Text 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.