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27f2a2dcc6
linux/fs/erofs
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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
..
compress.h erofs: introduce multi-reference pclusters (fully-referenced) 2022-07-22 21:44:27 +08:00
data.c erofs: enable large folios for iomap mode 2022-12-07 10:52:06 +08:00
decompressor_lzma.c erofs: introduce partial-referenced pclusters 2022-09-26 23:55:43 +08:00
decompressor.c erofs: support interlaced uncompressed data for compressed files 2022-09-23 10:55:56 +08:00
dir.c erofs: update ctx->pos for every emitted dirent 2022-07-31 22:26:29 +08:00
erofs_fs.h erofs: introduce partial-referenced pclusters 2022-09-26 23:55:43 +08:00
fscache.c erofs: check the uniqueness of fsid in shared domain in advance 2022-12-07 10:53:40 +08:00
inode.c erofs: enable large folios for iomap mode 2022-12-07 10:52:06 +08:00
internal.h erofs: check the uniqueness of fsid in shared domain in advance 2022-12-07 10:53:40 +08:00
Kconfig erofs: register fscache volume 2022-05-18 00:11:19 +08:00
Makefile erofs: register fscache volume 2022-05-18 00:11:19 +08:00
namei.c erofs: clean up erofs_iget() 2022-09-27 17:27:45 +08:00
pcpubuf.c erofs: get rid of ->lru usage 2021-10-25 08:22:59 +08:00
super.c erofs: check the uniqueness of fsid in shared domain in advance 2022-12-07 10:53:40 +08:00
sysfs.c erofs: fix use-after-free of fsid and domain_id string 2022-11-10 09:53:20 +08:00
tagptr.h erofs: clean up file headers & footers 2021-06-08 00:41:24 +08:00
utils.c mm: shrinkers: provide shrinkers with names 2022-07-03 18:08:40 -07:00
xattr.c erofs: use meta buffers for xattr operations 2022-01-04 23:47:08 +08:00
xattr.h erofs: clean up unnecessary code and comments 2022-09-27 17:27:25 +08:00
zdata.c Changes since last update: 2022-11-15 10:30:34 -08:00
zdata.h erofs: shouldn't churn the mapping page for duplicated copies 2022-10-17 06:55:49 +08:00
zmap.c erofs: fix illegal unmapped accesses in z_erofs_fill_inode_lazy() 2022-10-17 06:55:48 +08:00