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| author | Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com> | 2024-09-03 17:16:12 +0200 |
|---|---|---|
| committer | Miklos Szeredi <mszeredi@redhat.com> | 2024-09-04 16:47:49 +0200 |
| commit | 2097154a10c6ee78be8796411e5d0ad81ee06ed6 (patch) | |
| tree | 84863cfe85a4756c0e93e5f3cf975c4d0162670c /fs/namespace.c | |
| parent | fuse: use correct name fuse_conn_list in docstring (diff) | |
| download | linux-2097154a10c6ee78be8796411e5d0ad81ee06ed6.tar.xz linux-2097154a10c6ee78be8796411e5d0ad81ee06ed6.zip | |
namespace: introduce SB_I_NOIDMAP flag
Right now we determine if filesystem support vfs idmappings or not basing
on the FS_ALLOW_IDMAP flag presence. This "static" way works perfecly well
for local filesystems like ext4, xfs, btrfs, etc. But for network-like
filesystems like fuse, cephfs this approach is not ideal, because sometimes
proper support of vfs idmaps requires some extensions for the on-wire
protocol, which implies that changes have to be made not only in the Linux
kernel code but also in the 3rd party components like libfuse, cephfs MDS
server and so on.
We have seen that issue during our work on cephfs idmapped mounts [1] with
Christian, but right now I'm working on the idmapped mounts support for
fuse/virtiofs and I think that it is a right time for this extension.
[1] 5ccd8530dd7 ("ceph: handle idmapped mounts in create_request_message()")
Suggested-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/namespace.c')
| -rw-r--r-- | fs/namespace.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index 328087a4df8a..d1702285c915 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -4436,6 +4436,10 @@ static int can_idmap_mount(const struct mount_kattr *kattr, struct mount *mnt) if (!(m->mnt_sb->s_type->fs_flags & FS_ALLOW_IDMAP)) return -EINVAL; + /* The filesystem has turned off idmapped mounts. */ + if (m->mnt_sb->s_iflags & SB_I_NOIDMAP) + return -EINVAL; + /* We're not controlling the superblock. */ if (!ns_capable(fs_userns, CAP_SYS_ADMIN)) return -EPERM; |