diff options
| -rw-r--r-- | MAINTAINERS | 9 | ||||
| -rw-r--r-- | fs/namespace.c | 30 | ||||
| -rw-r--r-- | tools/testing/selftests/mount_setattr/mount_setattr_test.c | 4 |
3 files changed, 41 insertions, 2 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index bd86ed9fbc79..7c85c4d35b59 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -9263,6 +9263,15 @@ S: Maintained W: https://github.com/o2genum/ideapad-slidebar F: drivers/input/misc/ideapad_slidebar.c +IDMAPPED MOUNTS +M: Christian Brauner <brauner@kernel.org> +L: linux-fsdevel@vger.kernel.org +S: Maintained +T: git git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux.git +F: Documentation/filesystems/idmappings.rst +F: tools/testing/selftests/mount_setattr/ +F: include/linux/mnt_idmapping.h + IDT VersaClock 5 CLOCK DRIVER M: Luca Ceresoli <luca@lucaceresoli.net> S: Maintained diff --git a/fs/namespace.c b/fs/namespace.c index 40b994a29e90..de6fae84f1a1 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -469,6 +469,24 @@ void mnt_drop_write_file(struct file *file) } EXPORT_SYMBOL(mnt_drop_write_file); +/** + * mnt_hold_writers - prevent write access to the given mount + * @mnt: mnt to prevent write access to + * + * Prevents write access to @mnt if there are no active writers for @mnt. + * This function needs to be called and return successfully before changing + * properties of @mnt that need to remain stable for callers with write access + * to @mnt. + * + * After this functions has been called successfully callers must pair it with + * a call to mnt_unhold_writers() in order to stop preventing write access to + * @mnt. + * + * Context: This function expects lock_mount_hash() to be held serializing + * setting MNT_WRITE_HOLD. + * Return: On success 0 is returned. + * On error, -EBUSY is returned. + */ static inline int mnt_hold_writers(struct mount *mnt) { mnt->mnt.mnt_flags |= MNT_WRITE_HOLD; @@ -500,6 +518,18 @@ static inline int mnt_hold_writers(struct mount *mnt) return 0; } +/** + * mnt_unhold_writers - stop preventing write access to the given mount + * @mnt: mnt to stop preventing write access to + * + * Stop preventing write access to @mnt allowing callers to gain write access + * to @mnt again. + * + * This function can only be called after a successful call to + * mnt_hold_writers(). + * + * Context: This function expects lock_mount_hash() to be held. + */ static inline void mnt_unhold_writers(struct mount *mnt) { /* diff --git a/tools/testing/selftests/mount_setattr/mount_setattr_test.c b/tools/testing/selftests/mount_setattr/mount_setattr_test.c index f31205f04ee0..8c5fea68ae67 100644 --- a/tools/testing/selftests/mount_setattr/mount_setattr_test.c +++ b/tools/testing/selftests/mount_setattr/mount_setattr_test.c @@ -1236,7 +1236,7 @@ static int get_userns_fd(unsigned long nsid, unsigned long hostid, unsigned long } /** - * Validate that an attached mount in our mount namespace can be idmapped. + * Validate that an attached mount in our mount namespace cannot be idmapped. * (The kernel enforces that the mount's mount namespace and the caller's mount * namespace match.) */ @@ -1259,7 +1259,7 @@ TEST_F(mount_setattr_idmapped, attached_mount_inside_current_mount_namespace) attr.userns_fd = get_userns_fd(0, 10000, 10000); ASSERT_GE(attr.userns_fd, 0); - ASSERT_EQ(sys_mount_setattr(open_tree_fd, "", AT_EMPTY_PATH, &attr, sizeof(attr)), 0); + ASSERT_NE(sys_mount_setattr(open_tree_fd, "", AT_EMPTY_PATH, &attr, sizeof(attr)), 0); ASSERT_EQ(close(attr.userns_fd), 0); ASSERT_EQ(close(open_tree_fd), 0); } |