diff options
| author | Christian Brauner <brauner@kernel.org> | 2026-04-27 10:26:03 +0200 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2026-05-11 23:13:01 +0200 |
| commit | dc4edae7f41dceb236553b61cda0383895293c90 (patch) | |
| tree | da4b78ba0fe6a7f9dc10728eb35656c1226a8930 /include/linux | |
| parent | 672697c37c9dfe05aabfd44ccb51c2877deb524e (diff) | |
fs: move SB_I_USERNS_VISIBLE to FS_USERNS_MOUNT_RESTRICTED
Whether a filesystem's mounts need to undergo a visibility check in user
namespaces is a static property of the filesystem type, not a runtime
property of each superblock instance. Both proc and sysfs always set
SB_I_USERNS_VISIBLE on their superblocks unconditionally (sysfs does so
on first creation, and subsequent mounts reuse the same superblock).
Move this flag from sb->s_iflags (SB_I_USERNS_VISIBLE) to
file_system_type->fs_flags (FS_USERNS_MOUNT_RESTRICTED) so the intent
is expressed at the filesystem type level where it belongs.
All check sites are updated to test sb->s_type->fs_flags instead of
sb->s_iflags. The SB_I_NOEXEC and SB_I_NODEV flags remain on the
superblock as they are runtime properties set during fill_super.
Link: https://patch.msgid.link/72887c5b6204dc3adf5a53104f0be6bd8bc4f6cd.1777278334.git.legion@kernel.org
Reviewed-by: Aleksa Sarai <aleksa@amutable.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/fs.h | 1 | ||||
| -rw-r--r-- | include/linux/fs/super_types.h | 1 |
2 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index c37bb3c7de8b..e7ff9f8b1485 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2281,6 +2281,7 @@ struct file_system_type { #define FS_MGTIME 64 /* FS uses multigrain timestamps */ #define FS_LBS 128 /* FS supports LBS */ #define FS_POWER_FREEZE 256 /* Always freeze on suspend/hibernate */ +#define FS_USERNS_MOUNT_RESTRICTED 512 /* Restrict mount in userns if not already visible */ #define FS_RENAME_DOES_D_MOVE 32768 /* FS will handle d_move() during rename() internally. */ int (*init_fs_context)(struct fs_context *); const struct fs_parameter_spec *parameters; diff --git a/include/linux/fs/super_types.h b/include/linux/fs/super_types.h index 383050e7fdf5..182efbeb9520 100644 --- a/include/linux/fs/super_types.h +++ b/include/linux/fs/super_types.h @@ -326,7 +326,6 @@ struct super_block { #define SB_I_STABLE_WRITES 0x00000008 /* don't modify blks until WB is done */ /* sb->s_iflags to limit user namespace mounts */ -#define SB_I_USERNS_VISIBLE 0x00000010 /* fstype already mounted */ #define SB_I_IMA_UNVERIFIABLE_SIGNATURE 0x00000020 #define SB_I_UNTRUSTED_MOUNTER 0x00000040 #define SB_I_EVM_HMAC_UNSUPPORTED 0x00000080 |