lkml.org 
[lkml]   [2022]   [Dec]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v2] erofs: check the uniqueness of fsid in shared domain in advance
From
On 2022/11/25 19:08, Hou Tao wrote:
> From: Hou Tao <houtao1@huawei.com>
>
> 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>
> Signed-off-by: Hou Tao <houtao1@huawei.com>

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,

\
 
 \ /
  Last update: 2022-12-06 15:13    [W:0.028 / U:0.488 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site