diff options
Diffstat (limited to 'fs/namespace.c')
-rw-r--r-- | fs/namespace.c | 353 |
1 files changed, 233 insertions, 120 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index d1edf26..7dba2ed 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -196,7 +196,7 @@ unsigned int mnt_get_count(struct vfsmount *mnt) #endif } -struct vfsmount *alloc_vfsmnt(const char *name) +static struct vfsmount *alloc_vfsmnt(const char *name) { struct vfsmount *mnt = kmem_cache_zalloc(mnt_cache, GFP_KERNEL); if (mnt) { @@ -466,15 +466,7 @@ static void __mnt_unmake_readonly(struct vfsmount *mnt) br_write_unlock(vfsmount_lock); } -void simple_set_mnt(struct vfsmount *mnt, struct super_block *sb) -{ - mnt->mnt_sb = sb; - mnt->mnt_root = dget(sb->s_root); -} - -EXPORT_SYMBOL(simple_set_mnt); - -void free_vfsmnt(struct vfsmount *mnt) +static void free_vfsmnt(struct vfsmount *mnt) { kfree(mnt->mnt_devname); mnt_free_id(mnt); @@ -678,6 +670,36 @@ static struct vfsmount *skip_mnt_tree(struct vfsmount *p) return p; } +struct vfsmount * +vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data) +{ + struct vfsmount *mnt; + struct dentry *root; + + if (!type) + return ERR_PTR(-ENODEV); + + mnt = alloc_vfsmnt(name); + if (!mnt) + return ERR_PTR(-ENOMEM); + + if (flags & MS_KERNMOUNT) + mnt->mnt_flags = MNT_INTERNAL; + + root = mount_fs(type, flags, name, data); + if (IS_ERR(root)) { + free_vfsmnt(mnt); + return ERR_CAST(root); + } + + mnt->mnt_root = root; + mnt->mnt_sb = root->d_sb; + mnt->mnt_mountpoint = mnt->mnt_root; + mnt->mnt_parent = mnt; + return mnt; +} +EXPORT_SYMBOL_GPL(vfs_kern_mount); + static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root, int flag) { @@ -978,7 +1000,13 @@ static int show_vfsmnt(struct seq_file *m, void *v) int err = 0; struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt }; - mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none"); + if (mnt->mnt_sb->s_op->show_devname) { + err = mnt->mnt_sb->s_op->show_devname(m, mnt); + if (err) + goto out; + } else { + mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none"); + } seq_putc(m, ' '); seq_path(m, &mnt_path, " \t\n\\"); seq_putc(m, ' '); @@ -1002,6 +1030,18 @@ const struct seq_operations mounts_op = { .show = show_vfsmnt }; +static int uuid_is_nil(u8 *uuid) +{ + int i; + u8 *cp = (u8 *)uuid; + + for (i = 0; i < 16; i++) { + if (*cp++) + return 0; + } + return 1; +} + static int show_mountinfo(struct seq_file *m, void *v) { struct proc_mounts *p = m->private; @@ -1013,7 +1053,12 @@ static int show_mountinfo(struct seq_file *m, void *v) seq_printf(m, "%i %i %u:%u ", mnt->mnt_id, mnt->mnt_parent->mnt_id, MAJOR(sb->s_dev), MINOR(sb->s_dev)); - seq_dentry(m, mnt->mnt_root, " \t\n\\"); + if (sb->s_op->show_path) + err = sb->s_op->show_path(m, mnt); + else + seq_dentry(m, mnt->mnt_root, " \t\n\\"); + if (err) + goto out; seq_putc(m, ' '); seq_path_root(m, &mnt_path, &root, " \t\n\\"); if (root.mnt != p->root.mnt || root.dentry != p->root.dentry) { @@ -1040,11 +1085,20 @@ static int show_mountinfo(struct seq_file *m, void *v) if (IS_MNT_UNBINDABLE(mnt)) seq_puts(m, " unbindable"); + if (!uuid_is_nil(mnt->mnt_sb->s_uuid)) + /* print the uuid */ + seq_printf(m, " uuid:%pU", mnt->mnt_sb->s_uuid); + /* Filesystem specific data */ seq_puts(m, " - "); show_type(m, sb); seq_putc(m, ' '); - mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none"); + if (sb->s_op->show_devname) + err = sb->s_op->show_devname(m, mnt); + else + mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none"); + if (err) + goto out; seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw"); err = show_sb_opts(m, sb); if (err) @@ -1070,11 +1124,15 @@ static int show_vfsstat(struct seq_file *m, void *v) int err = 0; /* device */ - if (mnt->mnt_devname) { - seq_puts(m, "device "); - mangle(m, mnt->mnt_devname); - } else - seq_puts(m, "no device"); + if (mnt->mnt_sb->s_op->show_devname) { + err = mnt->mnt_sb->s_op->show_devname(m, mnt); + } else { + if (mnt->mnt_devname) { + seq_puts(m, "device "); + mangle(m, mnt->mnt_devname); + } else + seq_puts(m, "no device"); + } /* mount point */ seq_puts(m, " mounted on "); @@ -1088,7 +1146,8 @@ static int show_vfsstat(struct seq_file *m, void *v) /* optional statistics */ if (mnt->mnt_sb->s_op->show_stats) { seq_putc(m, ' '); - err = mnt->mnt_sb->s_op->show_stats(m, mnt); + if (!err) + err = mnt->mnt_sb->s_op->show_stats(m, mnt); } seq_putc(m, '\n'); @@ -1604,9 +1663,35 @@ static int attach_recursive_mnt(struct vfsmount *source_mnt, return err; } +static int lock_mount(struct path *path) +{ + struct vfsmount *mnt; +retry: + mutex_lock(&path->dentry->d_inode->i_mutex); + if (unlikely(cant_mount(path->dentry))) { + mutex_unlock(&path->dentry->d_inode->i_mutex); + return -ENOENT; + } + down_write(&namespace_sem); + mnt = lookup_mnt(path); + if (likely(!mnt)) + return 0; + up_write(&namespace_sem); + mutex_unlock(&path->dentry->d_inode->i_mutex); + path_put(path); + path->mnt = mnt; + path->dentry = dget(mnt->mnt_root); + goto retry; +} + +static void unlock_mount(struct path *path) +{ + up_write(&namespace_sem); + mutex_unlock(&path->dentry->d_inode->i_mutex); +} + static int graft_tree(struct vfsmount *mnt, struct path *path) { - int err; if (mnt->mnt_sb->s_flags & MS_NOUSER) return -EINVAL; @@ -1614,16 +1699,10 @@ static int graft_tree(struct vfsmount *mnt, struct path *path) S_ISDIR(mnt->mnt_root->d_inode->i_mode)) return -ENOTDIR; - err = -ENOENT; - mutex_lock(&path->dentry->d_inode->i_mutex); - if (cant_mount(path->dentry)) - goto out_unlock; + if (d_unlinked(path->dentry)) + return -ENOENT; - if (!d_unlinked(path->dentry)) - err = attach_recursive_mnt(mnt, path, NULL); -out_unlock: - mutex_unlock(&path->dentry->d_inode->i_mutex); - return err; + return attach_recursive_mnt(mnt, path, NULL); } /* @@ -1686,6 +1765,7 @@ static int do_change_type(struct path *path, int flag) static int do_loopback(struct path *path, char *old_name, int recurse) { + LIST_HEAD(umount_list); struct path old_path; struct vfsmount *mnt = NULL; int err = mount_is_safe(path); @@ -1697,13 +1777,16 @@ static int do_loopback(struct path *path, char *old_name, if (err) return err; - down_write(&namespace_sem); + err = lock_mount(path); + if (err) + goto out; + err = -EINVAL; if (IS_MNT_UNBINDABLE(old_path.mnt)) - goto out; + goto out2; if (!check_mnt(path->mnt) || !check_mnt(old_path.mnt)) - goto out; + goto out2; err = -ENOMEM; if (recurse) @@ -1712,20 +1795,18 @@ static int do_loopback(struct path *path, char *old_name, mnt = clone_mnt(old_path.mnt, old_path.dentry, 0); if (!mnt) - goto out; + goto out2; err = graft_tree(mnt, path); if (err) { - LIST_HEAD(umount_list); - br_write_lock(vfsmount_lock); umount_tree(mnt, 0, &umount_list); br_write_unlock(vfsmount_lock); - release_mounts(&umount_list); } - +out2: + unlock_mount(path); + release_mounts(&umount_list); out: - up_write(&namespace_sem); path_put(&old_path); return err; } @@ -1767,6 +1848,10 @@ static int do_remount(struct path *path, int flags, int mnt_flags, if (path->dentry != path->mnt->mnt_root) return -EINVAL; + err = security_sb_remount(sb, data); + if (err) + return err; + down_write(&sb->s_umount); if (flags & MS_BIND) err = change_mount_flags(path->mnt, flags); @@ -1810,18 +1895,12 @@ static int do_move_mount(struct path *path, char *old_name) if (err) return err; - down_write(&namespace_sem); - err = follow_down(path, true); + err = lock_mount(path); if (err < 0) goto out; err = -EINVAL; if (!check_mnt(path->mnt) || !check_mnt(old_path.mnt)) - goto out; - - err = -ENOENT; - mutex_lock(&path->dentry->d_inode->i_mutex); - if (cant_mount(path->dentry)) goto out1; if (d_unlinked(path->dentry)) @@ -1863,16 +1942,87 @@ static int do_move_mount(struct path *path, char *old_name) * automatically */ list_del_init(&old_path.mnt->mnt_expire); out1: - mutex_unlock(&path->dentry->d_inode->i_mutex); + unlock_mount(path); out: - up_write(&namespace_sem); if (!err) path_put(&parent_path); path_put(&old_path); return err; } -static int do_add_mount(struct vfsmount *, struct path *, int); +static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype) +{ + int err; + const char *subtype = strchr(fstype, '.'); + if (subtype) { + subtype++; + err = -EINVAL; + if (!subtype[0]) + goto err; + } else + subtype = ""; + + mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL); + err = -ENOMEM; + if (!mnt->mnt_sb->s_subtype) + goto err; + return mnt; + + err: + mntput(mnt); + return ERR_PTR(err); +} + +struct vfsmount * +do_kern_mount(const char *fstype, int flags, const char *name, void *data) +{ + struct file_system_type *type = get_fs_type(fstype); + struct vfsmount *mnt; + if (!type) + return ERR_PTR(-ENODEV); + mnt = vfs_kern_mount(type, flags, name, data); + if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) && + !mnt->mnt_sb->s_subtype) + mnt = fs_set_subtype(mnt, fstype); + put_filesystem(type); + return mnt; +} +EXPORT_SYMBOL_GPL(do_kern_mount); + +/* + * add a mount into a namespace's mount tree + */ +static int do_add_mount(struct vfsmount *newmnt, struct path *path, int mnt_flags) +{ + int err; + + mnt_flags &= ~(MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL); + + err = lock_mount(path); + if (err) + return err; + + err = -EINVAL; + if (!(mnt_flags & MNT_SHRINKABLE) && !check_mnt(path->mnt)) + goto unlock; + + /* Refuse the same filesystem on the same mount point */ + err = -EBUSY; + if (path->mnt->mnt_sb == newmnt->mnt_sb && + path->mnt->mnt_root == path->dentry) + goto unlock; + + err = -EINVAL; + if (S_ISLNK(newmnt->mnt_root->d_inode->i_mode)) + goto unlock; + + newmnt->mnt_flags = mnt_flags; + err = graft_tree(newmnt, path); + +unlock: + unlock_mount(path); + return err; +} /* * create a new mount for userspace and request it to be added into the @@ -1932,43 +2082,6 @@ fail: return err; } -/* - * add a mount into a namespace's mount tree - */ -static int do_add_mount(struct vfsmount *newmnt, struct path *path, int mnt_flags) -{ - int err; - - mnt_flags &= ~(MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL); - - down_write(&namespace_sem); - /* Something was mounted here while we slept */ - err = follow_down(path, true); - if (err < 0) - goto unlock; - - err = -EINVAL; - if (!(mnt_flags & MNT_SHRINKABLE) && !check_mnt(path->mnt)) - goto unlock; - - /* Refuse the same filesystem on the same mount point */ - err = -EBUSY; - if (path->mnt->mnt_sb == newmnt->mnt_sb && - path->mnt->mnt_root == path->dentry) - goto unlock; - - err = -EINVAL; - if (S_ISLNK(newmnt->mnt_root->d_inode->i_mode)) - goto unlock; - - newmnt->mnt_flags = mnt_flags; - err = graft_tree(newmnt, path); - -unlock: - up_write(&namespace_sem); - return err; -} - /** * mnt_set_expiry - Put a mount on an expiration list * @mnt: The mount to list. @@ -2469,65 +2582,60 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root, error = user_path_dir(new_root, &new); if (error) goto out0; - error = -EINVAL; - if (!check_mnt(new.mnt)) - goto out1; error = user_path_dir(put_old, &old); if (error) goto out1; error = security_sb_pivotroot(&old, &new); - if (error) { - path_put(&old); - goto out1; - } + if (error) + goto out2; get_fs_root(current->fs, &root); - down_write(&namespace_sem); - mutex_lock(&old.dentry->d_inode->i_mutex); + error = lock_mount(&old); + if (error) + goto out3; + error = -EINVAL; if (IS_MNT_SHARED(old.mnt) || IS_MNT_SHARED(new.mnt->mnt_parent) || IS_MNT_SHARED(root.mnt->mnt_parent)) - goto out2; - if (!check_mnt(root.mnt)) - goto out2; + goto out4; + if (!check_mnt(root.mnt) || !check_mnt(new.mnt)) + goto out4; error = -ENOENT; - if (cant_mount(old.dentry)) - goto out2; if (d_unlinked(new.dentry)) - goto out2; + goto out4; if (d_unlinked(old.dentry)) - goto out2; + goto out4; error = -EBUSY; if (new.mnt == root.mnt || old.mnt == root.mnt) - goto out2; /* loop, on the same file system */ + goto out4; /* loop, on the same file system */ error = -EINVAL; if (root.mnt->mnt_root != root.dentry) - goto out2; /* not a mountpoint */ + goto out4; /* not a mountpoint */ if (root.mnt->mnt_parent == root.mnt) - goto out2; /* not attached */ + goto out4; /* not attached */ if (new.mnt->mnt_root != new.dentry) - goto out2; /* not a mountpoint */ + goto out4; /* not a mountpoint */ if (new.mnt->mnt_parent == new.mnt) - goto out2; /* not attached */ + goto out4; /* not attached */ /* make sure we can reach put_old from new_root */ tmp = old.mnt; - br_write_lock(vfsmount_lock); if (tmp != new.mnt) { for (;;) { if (tmp->mnt_parent == tmp) - goto out3; /* already mounted on put_old */ + goto out4; /* already mounted on put_old */ if (tmp->mnt_parent == new.mnt) break; tmp = tmp->mnt_parent; } if (!is_subdir(tmp->mnt_mountpoint, new.dentry)) - goto out3; + goto out4; } else if (!is_subdir(old.dentry, new.dentry)) - goto out3; + goto out4; + br_write_lock(vfsmount_lock); detach_mnt(new.mnt, &parent_path); detach_mnt(root.mnt, &root_parent); /* mount old root on put_old */ @@ -2537,22 +2645,21 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root, touch_mnt_namespace(current->nsproxy->mnt_ns); br_write_unlock(vfsmount_lock); chroot_fs_refs(&root, &new); - error = 0; - path_put(&root_parent); - path_put(&parent_path); -out2: - mutex_unlock(&old.dentry->d_inode->i_mutex); - up_write(&namespace_sem); +out4: + unlock_mount(&old); + if (!error) { + path_put(&root_parent); + path_put(&parent_path); + } +out3: path_put(&root); +out2: path_put(&old); out1: path_put(&new); out0: return error; -out3: - br_write_unlock(vfsmount_lock); - goto out2; } static void __init init_mount_tree(void) @@ -2594,7 +2701,7 @@ void __init mnt_init(void) if (!mount_hashtable) panic("Failed to allocate mount hash table\n"); - printk("Mount-cache hash table entries: %lu\n", HASH_SIZE); + printk(KERN_INFO "Mount-cache hash table entries: %lu\n", HASH_SIZE); for (u = 0; u < HASH_SIZE; u++) INIT_LIST_HEAD(&mount_hashtable[u]); @@ -2627,3 +2734,9 @@ void put_mnt_ns(struct mnt_namespace *ns) kfree(ns); } EXPORT_SYMBOL(put_mnt_ns); + +struct vfsmount *kern_mount_data(struct file_system_type *type, void *data) +{ + return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data); +} +EXPORT_SYMBOL_GPL(kern_mount_data); |