X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Fnamespace.c;h=bdc3cb4fd2220c6fde0f35159a902768a75d60f6;hb=57ecb34febc4c133ca0ccc7817796605a78a01d3;hp=120b8a6b99ed6579c2124164bc47b689ea7837f7;hpb=96029c4e09ccbd73a6d0ed2b29e80bf2586ad7ef;p=safe%2Fjmp%2Flinux-2.6 diff --git a/fs/namespace.c b/fs/namespace.c index 120b8a6..bdc3cb4 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -42,6 +43,8 @@ __cacheline_aligned_in_smp DEFINE_SPINLOCK(vfsmount_lock); static int event; static DEFINE_IDA(mnt_id_ida); static DEFINE_IDA(mnt_group_ida); +static int mnt_id_start = 0; +static int mnt_group_start = 1; static struct list_head *mount_hashtable __read_mostly; static struct kmem_cache *mnt_cache __read_mostly; @@ -69,7 +72,9 @@ static int mnt_alloc_id(struct vfsmount *mnt) retry: ida_pre_get(&mnt_id_ida, GFP_KERNEL); spin_lock(&vfsmount_lock); - res = ida_get_new(&mnt_id_ida, &mnt->mnt_id); + res = ida_get_new_above(&mnt_id_ida, mnt_id_start, &mnt->mnt_id); + if (!res) + mnt_id_start = mnt->mnt_id + 1; spin_unlock(&vfsmount_lock); if (res == -EAGAIN) goto retry; @@ -79,8 +84,11 @@ retry: static void mnt_free_id(struct vfsmount *mnt) { + int id = mnt->mnt_id; spin_lock(&vfsmount_lock); - ida_remove(&mnt_id_ida, mnt->mnt_id); + ida_remove(&mnt_id_ida, id); + if (mnt_id_start > id) + mnt_id_start = id; spin_unlock(&vfsmount_lock); } @@ -91,10 +99,18 @@ static void mnt_free_id(struct vfsmount *mnt) */ static int mnt_alloc_group_id(struct vfsmount *mnt) { + int res; + if (!ida_pre_get(&mnt_group_ida, GFP_KERNEL)) return -ENOMEM; - return ida_get_new_above(&mnt_group_ida, 1, &mnt->mnt_group_id); + res = ida_get_new_above(&mnt_group_ida, + mnt_group_start, + &mnt->mnt_group_id); + if (!res) + mnt_group_start = mnt->mnt_group_id + 1; + + return res; } /* @@ -102,7 +118,10 @@ static int mnt_alloc_group_id(struct vfsmount *mnt) */ void mnt_release_group_id(struct vfsmount *mnt) { - ida_remove(&mnt_group_ida, mnt->mnt_group_id); + int id = mnt->mnt_group_id; + ida_remove(&mnt_group_ida, id); + if (mnt_group_start > id) + mnt_group_start = id; mnt->mnt_group_id = 0; } @@ -297,7 +316,8 @@ EXPORT_SYMBOL_GPL(mnt_clone_write); */ int mnt_want_write_file(struct file *file) { - if (!(file->f_mode & FMODE_WRITE)) + struct inode *inode = file->f_dentry->d_inode; + if (!(file->f_mode & FMODE_WRITE) || special_file(inode->i_mode)) return mnt_want_write(file->f_path.mnt); else return mnt_clone_write(file->f_path.mnt); @@ -1060,11 +1080,8 @@ static int do_umount(struct vfsmount *mnt, int flags) * we just try to remount it readonly. */ down_write(&sb->s_umount); - if (!(sb->s_flags & MS_RDONLY)) { - lock_kernel(); + if (!(sb->s_flags & MS_RDONLY)) retval = do_remount_sb(sb, MS_RDONLY, NULL, 0); - unlock_kernel(); - } up_write(&sb->s_umount); return retval; } @@ -1384,7 +1401,7 @@ static int graft_tree(struct vfsmount *mnt, struct path *path) goto out_unlock; err = -ENOENT; - if (IS_ROOT(path->dentry) || !d_unhashed(path->dentry)) + if (!d_unlinked(path->dentry)) err = attach_recursive_mnt(mnt, path, NULL); out_unlock: mutex_unlock(&path->dentry->d_inode->i_mutex); @@ -1566,7 +1583,7 @@ static int do_move_mount(struct path *path, char *old_name) if (IS_DEADDIR(path->dentry->d_inode)) goto out1; - if (!IS_ROOT(path->dentry) && d_unhashed(path->dentry)) + if (d_unlinked(path->dentry)) goto out1; err = -EINVAL; @@ -1623,14 +1640,16 @@ static int do_new_mount(struct path *path, char *type, int flags, { struct vfsmount *mnt; - if (!type || !memchr(type, 0, PAGE_SIZE)) + if (!type) return -EINVAL; /* we need capabilities... */ if (!capable(CAP_SYS_ADMIN)) return -EPERM; + lock_kernel(); mnt = do_kern_mount(type, flags, name, data); + unlock_kernel(); if (IS_ERR(mnt)) return PTR_ERR(mnt); @@ -1852,6 +1871,23 @@ int copy_mount_options(const void __user * data, unsigned long *where) return 0; } +int copy_mount_string(const void __user *data, char **where) +{ + char *tmp; + + if (!data) { + *where = NULL; + return 0; + } + + tmp = strndup_user(data, PAGE_SIZE); + if (IS_ERR(tmp)) + return PTR_ERR(tmp); + + *where = tmp; + return 0; +} + /* * Flags is a 32-bit value that allows up to 31 non-fs dependent flags to * be given to the mount() call (ie: read-only, no-dev, no-suid etc). @@ -1881,8 +1917,6 @@ long do_mount(char *dev_name, char *dir_name, char *type_page, if (!dir_name || !*dir_name || !memchr(dir_name, 0, PAGE_SIZE)) return -EINVAL; - if (dev_name && !memchr(dev_name, 0, PAGE_SIZE)) - return -EINVAL; if (data_page) ((char *)data_page)[PAGE_SIZE - 1] = 0; @@ -1938,6 +1972,21 @@ dput_out: return retval; } +static struct mnt_namespace *alloc_mnt_ns(void) +{ + struct mnt_namespace *new_ns; + + new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL); + if (!new_ns) + return ERR_PTR(-ENOMEM); + atomic_set(&new_ns->count, 1); + new_ns->root = NULL; + INIT_LIST_HEAD(&new_ns->list); + init_waitqueue_head(&new_ns->poll); + new_ns->event = 0; + return new_ns; +} + /* * Allocate a new namespace structure and populate it with contents * copied from the namespace of the passed in task structure. @@ -1949,14 +1998,9 @@ static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns, struct vfsmount *rootmnt = NULL, *pwdmnt = NULL; struct vfsmount *p, *q; - new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL); - if (!new_ns) - return ERR_PTR(-ENOMEM); - - atomic_set(&new_ns->count, 1); - INIT_LIST_HEAD(&new_ns->list); - init_waitqueue_head(&new_ns->poll); - new_ns->event = 0; + new_ns = alloc_mnt_ns(); + if (IS_ERR(new_ns)) + return new_ns; down_write(&namespace_sem); /* First pass: copy the tree topology */ @@ -2020,45 +2064,63 @@ struct mnt_namespace *copy_mnt_ns(unsigned long flags, struct mnt_namespace *ns, return new_ns; } +/** + * create_mnt_ns - creates a private namespace and adds a root filesystem + * @mnt: pointer to the new root filesystem mountpoint + */ +struct mnt_namespace *create_mnt_ns(struct vfsmount *mnt) +{ + struct mnt_namespace *new_ns; + + new_ns = alloc_mnt_ns(); + if (!IS_ERR(new_ns)) { + mnt->mnt_ns = new_ns; + new_ns->root = mnt; + list_add(&new_ns->list, &new_ns->root->mnt_list); + } + return new_ns; +} +EXPORT_SYMBOL(create_mnt_ns); + SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name, char __user *, type, unsigned long, flags, void __user *, data) { - int retval; + int ret; + char *kernel_type; + char *kernel_dir; + char *kernel_dev; unsigned long data_page; - unsigned long type_page; - unsigned long dev_page; - char *dir_page; - retval = copy_mount_options(type, &type_page); - if (retval < 0) - return retval; + ret = copy_mount_string(type, &kernel_type); + if (ret < 0) + goto out_type; - dir_page = getname(dir_name); - retval = PTR_ERR(dir_page); - if (IS_ERR(dir_page)) - goto out1; + kernel_dir = getname(dir_name); + if (IS_ERR(kernel_dir)) { + ret = PTR_ERR(kernel_dir); + goto out_dir; + } - retval = copy_mount_options(dev_name, &dev_page); - if (retval < 0) - goto out2; + ret = copy_mount_string(dev_name, &kernel_dev); + if (ret < 0) + goto out_dev; - retval = copy_mount_options(data, &data_page); - if (retval < 0) - goto out3; + ret = copy_mount_options(data, &data_page); + if (ret < 0) + goto out_data; - lock_kernel(); - retval = do_mount((char *)dev_page, dir_page, (char *)type_page, - flags, (void *)data_page); - unlock_kernel(); - free_page(data_page); + ret = do_mount(kernel_dev, kernel_dir, kernel_type, flags, + (void *) data_page); -out3: - free_page(dev_page); -out2: - putname(dir_page); -out1: - free_page(type_page); - return retval; + free_page(data_page); +out_data: + kfree(kernel_dev); +out_dev: + putname(kernel_dir); +out_dir: + kfree(kernel_type); +out_type: + return ret; } /* @@ -2129,9 +2191,9 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root, error = -ENOENT; if (IS_DEADDIR(new.dentry->d_inode)) goto out2; - if (d_unhashed(new.dentry) && !IS_ROOT(new.dentry)) + if (d_unlinked(new.dentry)) goto out2; - if (d_unhashed(old.dentry) && !IS_ROOT(old.dentry)) + if (d_unlinked(old.dentry)) goto out2; error = -EBUSY; if (new.mnt == root.mnt || @@ -2197,16 +2259,9 @@ static void __init init_mount_tree(void) mnt = do_kern_mount("rootfs", 0, "rootfs", NULL); if (IS_ERR(mnt)) panic("Can't create rootfs"); - ns = kmalloc(sizeof(*ns), GFP_KERNEL); - if (!ns) + ns = create_mnt_ns(mnt); + if (IS_ERR(ns)) panic("Can't allocate initial namespace"); - atomic_set(&ns->count, 1); - INIT_LIST_HEAD(&ns->list); - init_waitqueue_head(&ns->poll); - ns->event = 0; - list_add(&mnt->mnt_list, &ns->list); - ns->root = mnt; - mnt->mnt_ns = ns; init_task.nsproxy->mnt_ns = ns; get_mnt_ns(ns); @@ -2249,10 +2304,14 @@ void __init mnt_init(void) init_mount_tree(); } -void __put_mnt_ns(struct mnt_namespace *ns) +void put_mnt_ns(struct mnt_namespace *ns) { - struct vfsmount *root = ns->root; + struct vfsmount *root; LIST_HEAD(umount_list); + + if (!atomic_dec_and_lock(&ns->count, &vfsmount_lock)) + return; + root = ns->root; ns->root = NULL; spin_unlock(&vfsmount_lock); down_write(&namespace_sem); @@ -2263,3 +2322,4 @@ void __put_mnt_ns(struct mnt_namespace *ns) release_mounts(&umount_list); kfree(ns); } +EXPORT_SYMBOL(put_mnt_ns);