diff options
Diffstat (limited to 'fs/namespace.c')
| -rw-r--r-- | fs/namespace.c | 67 |
1 files changed, 37 insertions, 30 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index bfc5cff0e1..3ffae74652 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -39,10 +39,10 @@ /* Maximum number of mounts in a mount namespace */ static unsigned int sysctl_mount_max __read_mostly = 100000; -static unsigned int m_hash_mask __read_mostly; -static unsigned int m_hash_shift __read_mostly; -static unsigned int mp_hash_mask __read_mostly; -static unsigned int mp_hash_shift __read_mostly; +static unsigned int m_hash_mask __ro_after_init; +static unsigned int m_hash_shift __ro_after_init; +static unsigned int mp_hash_mask __ro_after_init; +static unsigned int mp_hash_shift __ro_after_init; static __initdata unsigned long mhash_entries; static int __init set_mhash_entries(char *str) @@ -68,9 +68,9 @@ static u64 event; static DEFINE_IDA(mnt_id_ida); static DEFINE_IDA(mnt_group_ida); -static struct hlist_head *mount_hashtable __read_mostly; -static struct hlist_head *mountpoint_hashtable __read_mostly; -static struct kmem_cache *mnt_cache __read_mostly; +static struct hlist_head *mount_hashtable __ro_after_init; +static struct hlist_head *mountpoint_hashtable __ro_after_init; +static struct kmem_cache *mnt_cache __ro_after_init; static DECLARE_RWSEM(namespace_sem); static HLIST_HEAD(unmounted); /* protected by namespace_sem */ static LIST_HEAD(ex_mountpoints); /* protected by namespace_sem */ @@ -86,7 +86,7 @@ struct mount_kattr { }; /* /sys/fs */ -struct kobject *fs_kobj; +struct kobject *fs_kobj __ro_after_init; EXPORT_SYMBOL_GPL(fs_kobj); /* @@ -330,16 +330,16 @@ static int mnt_is_readonly(struct vfsmount *mnt) * can determine when writes are able to occur to a filesystem. */ /** - * __mnt_want_write - get write access to a mount without freeze protection + * mnt_get_write_access - get write access to a mount without freeze protection * @m: the mount on which to take a write * * This tells the low-level filesystem that a write is about to be performed to * it, and makes sure that writes are allowed (mnt it read-write) before * returning success. This operation does not protect against filesystem being - * frozen. When the write operation is finished, __mnt_drop_write() must be + * frozen. When the write operation is finished, mnt_put_write_access() must be * called. This is effectively a refcount. */ -int __mnt_want_write(struct vfsmount *m) +int mnt_get_write_access(struct vfsmount *m) { struct mount *mnt = real_mount(m); int ret = 0; @@ -386,6 +386,7 @@ int __mnt_want_write(struct vfsmount *m) return ret; } +EXPORT_SYMBOL_GPL(mnt_get_write_access); /** * mnt_want_write - get write access to a mount @@ -401,7 +402,7 @@ int mnt_want_write(struct vfsmount *m) int ret; sb_start_write(m->mnt_sb); - ret = __mnt_want_write(m); + ret = mnt_get_write_access(m); if (ret) sb_end_write(m->mnt_sb); return ret; @@ -409,15 +410,15 @@ int mnt_want_write(struct vfsmount *m) EXPORT_SYMBOL_GPL(mnt_want_write); /** - * __mnt_want_write_file - get write access to a file's mount + * mnt_get_write_access_file - get write access to a file's mount * @file: the file who's mount on which to take a write * - * This is like __mnt_want_write, but if the file is already open for writing it + * This is like mnt_get_write_access, but if @file is already open for write it * skips incrementing mnt_writers (since the open file already has a reference) * and instead only does the check for emergency r/o remounts. This must be - * paired with __mnt_drop_write_file. + * paired with mnt_put_write_access_file. */ -int __mnt_want_write_file(struct file *file) +int mnt_get_write_access_file(struct file *file) { if (file->f_mode & FMODE_WRITER) { /* @@ -428,7 +429,7 @@ int __mnt_want_write_file(struct file *file) return -EROFS; return 0; } - return __mnt_want_write(file->f_path.mnt); + return mnt_get_write_access(file->f_path.mnt); } /** @@ -445,7 +446,7 @@ int mnt_want_write_file(struct file *file) int ret; sb_start_write(file_inode(file)->i_sb); - ret = __mnt_want_write_file(file); + ret = mnt_get_write_access_file(file); if (ret) sb_end_write(file_inode(file)->i_sb); return ret; @@ -453,19 +454,20 @@ int mnt_want_write_file(struct file *file) EXPORT_SYMBOL_GPL(mnt_want_write_file); /** - * __mnt_drop_write - give up write access to a mount + * mnt_put_write_access - give up write access to a mount * @mnt: the mount on which to give up write access * * Tells the low-level filesystem that we are done * performing writes to it. Must be matched with - * __mnt_want_write() call above. + * mnt_get_write_access() call above. */ -void __mnt_drop_write(struct vfsmount *mnt) +void mnt_put_write_access(struct vfsmount *mnt) { preempt_disable(); mnt_dec_writers(real_mount(mnt)); preempt_enable(); } +EXPORT_SYMBOL_GPL(mnt_put_write_access); /** * mnt_drop_write - give up write access to a mount @@ -477,20 +479,20 @@ void __mnt_drop_write(struct vfsmount *mnt) */ void mnt_drop_write(struct vfsmount *mnt) { - __mnt_drop_write(mnt); + mnt_put_write_access(mnt); sb_end_write(mnt->mnt_sb); } EXPORT_SYMBOL_GPL(mnt_drop_write); -void __mnt_drop_write_file(struct file *file) +void mnt_put_write_access_file(struct file *file) { if (!(file->f_mode & FMODE_WRITER)) - __mnt_drop_write(file->f_path.mnt); + mnt_put_write_access(file->f_path.mnt); } void mnt_drop_write_file(struct file *file) { - __mnt_drop_write_file(file); + mnt_put_write_access_file(file); sb_end_write(file_inode(file)->i_sb); } EXPORT_SYMBOL(mnt_drop_write_file); @@ -1344,9 +1346,9 @@ void mntput(struct vfsmount *mnt) { if (mnt) { struct mount *m = real_mount(mnt); - /* avoid cacheline pingpong, hope gcc doesn't get "smart" */ + /* avoid cacheline pingpong */ if (unlikely(m->mnt_expiry_mark)) - m->mnt_expiry_mark = 0; + WRITE_ONCE(m->mnt_expiry_mark, 0); mntput_no_expire(m); } } @@ -4470,10 +4472,15 @@ static int do_mount_setattr(struct path *path, struct mount_kattr *kattr) /* * If this is an attached mount make sure it's located in the callers * mount namespace. If it's not don't let the caller interact with it. - * If this is a detached mount make sure it has an anonymous mount - * namespace attached to it, i.e. we've created it via OPEN_TREE_CLONE. + * + * If this mount doesn't have a parent it's most often simply a + * detached mount with an anonymous mount namespace. IOW, something + * that's simply not attached yet. But there are apparently also users + * that do change mount properties on the rootfs itself. That obviously + * neither has a parent nor is it a detached mount so we cannot + * unconditionally check for detached mounts. */ - if (!(mnt_has_parent(mnt) ? check_mnt(mnt) : is_anon_ns(mnt->mnt_ns))) + if ((mnt_has_parent(mnt) || !is_anon_ns(mnt->mnt_ns)) && !check_mnt(mnt)) goto out; /* |