X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=fs%2Fnamespace.c;h=a2f5048b8a80b3628b4eaeef0e93c897623a6208;hb=97bf2856c6014879bd04983a3e9dfcdac1e7fe85;hp=dfeac2193b69376089825d4b5208620e5a4096d8;hpb=a8e794ca871505c8ea96cc102f4ad555c5231d7f;p=linux-2.6.git diff --git a/fs/namespace.c b/fs/namespace.c index dfeac2193..a2f5048b8 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -8,58 +8,70 @@ * Heavily rewritten. */ -#include +#include #include #include #include #include +#include #include #include +#include #include +#include #include -#include +#include #include #include #include +#include +#include +#include +#include +#include +#include #include +#include +#include "pnode.h" -extern int __init init_rootfs(void); +/* spinlock for vfsmount related operations, inplace of dcache_lock */ +__cacheline_aligned_in_smp DEFINE_SPINLOCK(vfsmount_lock); -#ifdef CONFIG_SYSFS -extern int __init sysfs_init(void); -#else -static inline int sysfs_init(void) -{ - return 0; -} -#endif +static int event; -/* spinlock for vfsmount related operations, inplace of dcache_lock */ -spinlock_t vfsmount_lock __cacheline_aligned_in_smp = SPIN_LOCK_UNLOCKED; -static struct list_head *mount_hashtable; -static int hash_mask, hash_bits; -static kmem_cache_t *mnt_cache; +static struct list_head *mount_hashtable __read_mostly; +static int hash_mask __read_mostly, hash_bits __read_mostly; +static struct kmem_cache *mnt_cache __read_mostly; +static struct rw_semaphore namespace_sem; + +/* /sys/fs */ +decl_subsys(fs, NULL, NULL); +EXPORT_SYMBOL_GPL(fs_subsys); static inline unsigned long hash(struct vfsmount *mnt, struct dentry *dentry) { - unsigned long tmp = ((unsigned long) mnt / L1_CACHE_BYTES); - tmp += ((unsigned long) dentry / L1_CACHE_BYTES); + unsigned long tmp = ((unsigned long)mnt / L1_CACHE_BYTES); + tmp += ((unsigned long)dentry / L1_CACHE_BYTES); tmp = tmp + (tmp >> hash_bits); return tmp & hash_mask; } struct vfsmount *alloc_vfsmnt(const char *name) { - struct vfsmount *mnt = kmem_cache_alloc(mnt_cache, GFP_KERNEL); + struct vfsmount *mnt = kmem_cache_alloc(mnt_cache, GFP_KERNEL); if (mnt) { memset(mnt, 0, sizeof(struct vfsmount)); - atomic_set(&mnt->mnt_count,1); + atomic_set(&mnt->mnt_count, 1); INIT_LIST_HEAD(&mnt->mnt_hash); INIT_LIST_HEAD(&mnt->mnt_child); INIT_LIST_HEAD(&mnt->mnt_mounts); INIT_LIST_HEAD(&mnt->mnt_list); + INIT_LIST_HEAD(&mnt->mnt_expire); + INIT_LIST_HEAD(&mnt->mnt_share); + INIT_LIST_HEAD(&mnt->mnt_slave_list); + INIT_LIST_HEAD(&mnt->mnt_slave); if (name) { - int size = strlen(name)+1; + int size = strlen(name) + 1; char *newname = kmalloc(size, GFP_KERNEL); if (newname) { memcpy(newname, name, size); @@ -70,6 +82,15 @@ struct vfsmount *alloc_vfsmnt(const char *name) return mnt; } +int simple_set_mnt(struct vfsmount *mnt, struct super_block *sb) +{ + mnt->mnt_sb = sb; + mnt->mnt_root = dget(sb->s_root); + return 0; +} + +EXPORT_SYMBOL(simple_set_mnt); + void free_vfsmnt(struct vfsmount *mnt) { kfree(mnt->mnt_devname); @@ -77,40 +98,63 @@ void free_vfsmnt(struct vfsmount *mnt) } /* - * Now, lookup_mnt increments the ref count before returning - * the vfsmount struct. + * find the first or last mount at @dentry on vfsmount @mnt depending on + * @dir. If @dir is set return the first mount else return the last mount. */ -struct vfsmount *lookup_mnt(struct vfsmount *mnt, struct dentry *dentry) +struct vfsmount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry, + int dir) { - struct list_head * head = mount_hashtable + hash(mnt, dentry); - struct list_head * tmp = head; + struct list_head *head = mount_hashtable + hash(mnt, dentry); + struct list_head *tmp = head; struct vfsmount *p, *found = NULL; - spin_lock(&vfsmount_lock); for (;;) { - tmp = tmp->next; + tmp = dir ? tmp->next : tmp->prev; p = NULL; if (tmp == head) break; p = list_entry(tmp, struct vfsmount, mnt_hash); if (p->mnt_parent == mnt && p->mnt_mountpoint == dentry) { - found = mntget(p); + found = p; break; } } - spin_unlock(&vfsmount_lock); return found; } -EXPORT_SYMBOL(lookup_mnt); - -static int check_mnt(struct vfsmount *mnt) +/* + * lookup_mnt increments the ref count before returning + * the vfsmount struct. + */ +struct vfsmount *lookup_mnt(struct vfsmount *mnt, struct dentry *dentry) { + struct vfsmount *child_mnt; spin_lock(&vfsmount_lock); - while (mnt->mnt_parent != mnt) - mnt = mnt->mnt_parent; + if ((child_mnt = __lookup_mnt(mnt, dentry, 1))) + mntget(child_mnt); spin_unlock(&vfsmount_lock); - return mnt == current->namespace->root; + return child_mnt; +} + +static inline int check_mnt(struct vfsmount *mnt) +{ + return mnt->mnt_ns == current->nsproxy->mnt_ns; +} + +static void touch_mnt_namespace(struct mnt_namespace *ns) +{ + if (ns) { + ns->event = ++event; + wake_up_interruptible(&ns->poll); + } +} + +static void __touch_mnt_namespace(struct mnt_namespace *ns) +{ + if (ns && ns->event != event) { + ns->event = event; + wake_up_interruptible(&ns->poll); + } } static void detach_mnt(struct vfsmount *mnt, struct nameidata *old_nd) @@ -124,13 +168,43 @@ static void detach_mnt(struct vfsmount *mnt, struct nameidata *old_nd) old_nd->dentry->d_mounted--; } +void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry, + struct vfsmount *child_mnt) +{ + child_mnt->mnt_parent = mntget(mnt); + child_mnt->mnt_mountpoint = dget(dentry); + dentry->d_mounted++; +} + static void attach_mnt(struct vfsmount *mnt, struct nameidata *nd) { - mnt->mnt_parent = mntget(nd->mnt); - mnt->mnt_mountpoint = dget(nd->dentry); - list_add(&mnt->mnt_hash, mount_hashtable+hash(nd->mnt, nd->dentry)); + mnt_set_mountpoint(nd->mnt, nd->dentry, mnt); + list_add_tail(&mnt->mnt_hash, mount_hashtable + + hash(nd->mnt, nd->dentry)); list_add_tail(&mnt->mnt_child, &nd->mnt->mnt_mounts); - nd->dentry->d_mounted++; +} + +/* + * the caller must hold vfsmount_lock + */ +static void commit_tree(struct vfsmount *mnt) +{ + struct vfsmount *parent = mnt->mnt_parent; + struct vfsmount *m; + LIST_HEAD(head); + struct mnt_namespace *n = parent->mnt_ns; + + BUG_ON(parent == mnt); + + list_add_tail(&head, &mnt->mnt_list); + list_for_each_entry(m, &head, mnt_list) + m->mnt_ns = n; + list_splice(&head, n->list.prev); + + list_add_tail(&mnt->mnt_hash, mount_hashtable + + hash(parent, mnt->mnt_mountpoint)); + list_add_tail(&mnt->mnt_child, &parent->mnt_mounts); + touch_mnt_namespace(n); } static struct vfsmount *next_mnt(struct vfsmount *p, struct vfsmount *root) @@ -149,8 +223,18 @@ static struct vfsmount *next_mnt(struct vfsmount *p, struct vfsmount *root) return list_entry(next, struct vfsmount, mnt_child); } -static struct vfsmount * -clone_mnt(struct vfsmount *old, struct dentry *root) +static struct vfsmount *skip_mnt_tree(struct vfsmount *p) +{ + struct list_head *prev = p->mnt_mounts.prev; + while (prev != &p->mnt_mounts) { + p = list_entry(prev, struct vfsmount, mnt_child); + prev = p->mnt_mounts.prev; + } + return p; +} + +static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root, + int flag) { struct super_block *sb = old->mnt_sb; struct vfsmount *mnt = alloc_vfsmnt(old->mnt_devname); @@ -162,11 +246,35 @@ clone_mnt(struct vfsmount *old, struct dentry *root) mnt->mnt_root = dget(root); mnt->mnt_mountpoint = mnt->mnt_root; mnt->mnt_parent = mnt; + mnt->mnt_tag = old->mnt_tag; + + if (flag & CL_SLAVE) { + list_add(&mnt->mnt_slave, &old->mnt_slave_list); + mnt->mnt_master = old; + CLEAR_MNT_SHARED(mnt); + } else { + if ((flag & CL_PROPAGATION) || IS_MNT_SHARED(old)) + list_add(&mnt->mnt_share, &old->mnt_share); + if (IS_MNT_SLAVE(old)) + list_add(&mnt->mnt_slave, &old->mnt_slave); + mnt->mnt_master = old->mnt_master; + } + if (flag & CL_MAKE_SHARED) + set_mnt_shared(mnt); + + /* stick the duplicate mount on the same expiry list + * as the original if that was on one */ + if (flag & CL_EXPIRE) { + spin_lock(&vfsmount_lock); + if (!list_empty(&old->mnt_expire)) + list_add(&mnt->mnt_expire, &old->mnt_expire); + spin_unlock(&vfsmount_lock); + } } return mnt; } -void __mntput(struct vfsmount *mnt) +static inline void __mntput(struct vfsmount *mnt) { struct super_block *sb = mnt->mnt_sb; dput(mnt->mnt_root); @@ -174,16 +282,55 @@ void __mntput(struct vfsmount *mnt) deactivate_super(sb); } -EXPORT_SYMBOL(__mntput); +void mntput_no_expire(struct vfsmount *mnt) +{ +repeat: + if (atomic_dec_and_lock(&mnt->mnt_count, &vfsmount_lock)) { + if (likely(!mnt->mnt_pinned)) { + spin_unlock(&vfsmount_lock); + __mntput(mnt); + return; + } + atomic_add(mnt->mnt_pinned + 1, &mnt->mnt_count); + mnt->mnt_pinned = 0; + spin_unlock(&vfsmount_lock); + acct_auto_close_mnt(mnt); + security_sb_umount_close(mnt); + goto repeat; + } +} + +EXPORT_SYMBOL(mntput_no_expire); + +void mnt_pin(struct vfsmount *mnt) +{ + spin_lock(&vfsmount_lock); + mnt->mnt_pinned++; + spin_unlock(&vfsmount_lock); +} + +EXPORT_SYMBOL(mnt_pin); + +void mnt_unpin(struct vfsmount *mnt) +{ + spin_lock(&vfsmount_lock); + if (mnt->mnt_pinned) { + atomic_inc(&mnt->mnt_count); + mnt->mnt_pinned--; + } + spin_unlock(&vfsmount_lock); +} + +EXPORT_SYMBOL(mnt_unpin); /* iterator */ static void *m_start(struct seq_file *m, loff_t *pos) { - struct namespace *n = m->private; + struct mnt_namespace *n = m->private; struct list_head *p; loff_t l = *pos; - down_read(&n->sem); + down_read(&namespace_sem); list_for_each(p, &n->list) if (!l--) return list_entry(p, struct vfsmount, mnt_list); @@ -192,16 +339,15 @@ static void *m_start(struct seq_file *m, loff_t *pos) static void *m_next(struct seq_file *m, void *v, loff_t *pos) { - struct namespace *n = m->private; + struct mnt_namespace *n = m->private; struct list_head *p = ((struct vfsmount *)v)->mnt_list.next; (*pos)++; - return p==&n->list ? NULL : list_entry(p, struct vfsmount, mnt_list); + return p == &n->list ? NULL : list_entry(p, struct vfsmount, mnt_list); } static void m_stop(struct seq_file *m, void *v) { - struct namespace *n = m->private; - up_read(&n->sem); + up_read(&namespace_sem); } static inline void mangle(struct seq_file *m, const char *s) @@ -209,46 +355,86 @@ static inline void mangle(struct seq_file *m, const char *s) seq_escape(m, s, " \t\n\\"); } +static int mnt_is_reachable(struct vfsmount *mnt) +{ + struct vfsmount *root_mnt; + struct dentry *root, *point; + int ret; + + if (mnt == mnt->mnt_ns->root) + return 1; + + spin_lock(&vfsmount_lock); + root_mnt = current->fs->rootmnt; + root = current->fs->root; + point = root; + + while ((mnt != mnt->mnt_parent) && (mnt != root_mnt)) { + point = mnt->mnt_mountpoint; + mnt = mnt->mnt_parent; + } + + ret = (mnt == root_mnt) && is_subdir(point, root); + + spin_unlock(&vfsmount_lock); + + return ret; +} + static int show_vfsmnt(struct seq_file *m, void *v) { struct vfsmount *mnt = v; int err = 0; static struct proc_fs_info { - int flag; - char *str; + int s_flag; + int mnt_flag; + char *set_str; + char *unset_str; } fs_info[] = { - { MS_SYNCHRONOUS, ",sync" }, - { MS_DIRSYNC, ",dirsync" }, - { MS_MANDLOCK, ",mand" }, - { MS_NOATIME, ",noatime" }, - { MS_NODIRATIME, ",nodiratime" }, - { 0, NULL } + { MS_RDONLY, MNT_RDONLY, "ro", "rw" }, + { MS_SYNCHRONOUS, 0, ",sync", NULL }, + { MS_DIRSYNC, 0, ",dirsync", NULL }, + { MS_MANDLOCK, 0, ",mand", NULL }, + { MS_TAGGED, 0, ",tag", NULL }, + { MS_NOATIME, MNT_NOATIME, ",noatime", NULL }, + { MS_NODIRATIME, MNT_NODIRATIME, ",nodiratime", NULL }, + { MS_RELATIME, MNT_RELATIME, ",relatime", NULL }, + { 0, MNT_NOSUID, ",nosuid", NULL }, + { 0, MNT_NODEV, ",nodev", NULL }, + { 0, MNT_NOEXEC, ",noexec", NULL }, + { 0, 0, NULL, NULL } }; - static struct proc_fs_info mnt_info[] = { - { MNT_NOSUID, ",nosuid" }, - { MNT_NODEV, ",nodev" }, - { MNT_NOEXEC, ",noexec" }, - { 0, NULL } - }; - struct proc_fs_info *fs_infop; + struct proc_fs_info *p; + unsigned long s_flags = mnt->mnt_sb->s_flags; + int mnt_flags = mnt->mnt_flags; if (vx_flags(VXF_HIDE_MOUNT, 0)) return 0; + if (!mnt_is_reachable(mnt) && !vx_check(0, VS_WATCH_P)) + return 0; - mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none"); - seq_putc(m, ' '); - seq_path(m, mnt, mnt->mnt_root, " \t\n\\"); - seq_putc(m, ' '); - mangle(m, mnt->mnt_sb->s_type->name); - seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? " ro" : " rw"); - for (fs_infop = fs_info; fs_infop->flag; fs_infop++) { - if (mnt->mnt_sb->s_flags & fs_infop->flag) - seq_puts(m, fs_infop->str); + if (!vx_check(0, VS_ADMIN|VS_WATCH) && + mnt == current->fs->rootmnt) { + seq_puts(m, "/dev/root / "); + } else { + mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none"); + seq_putc(m, ' '); + seq_path(m, mnt, mnt->mnt_root, " \t\n\\"); + seq_putc(m, ' '); } - for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) { - if (mnt->mnt_flags & fs_infop->flag) - seq_puts(m, fs_infop->str); + mangle(m, mnt->mnt_sb->s_type->name); + seq_putc(m, ' '); + for (p = fs_info; (p->s_flag | p->mnt_flag) ; p++) { + if ((s_flags & p->s_flag) || (mnt_flags & p->mnt_flag)) { + if (p->set_str) + seq_puts(m, p->set_str); + } else { + if (p->unset_str) + seq_puts(m, p->unset_str); + } } + if (mnt->mnt_flags & MNT_TAGID) + seq_printf(m, ",tag=%d", mnt->mnt_tag); if (mnt->mnt_sb->s_op->show_options) err = mnt->mnt_sb->s_op->show_options(m, mnt); seq_puts(m, " 0 0\n"); @@ -262,73 +448,180 @@ struct seq_operations mounts_op = { .show = show_vfsmnt }; -/* +static int show_vfsstat(struct seq_file *m, void *v) +{ + struct vfsmount *mnt = v; + int err = 0; + + if (vx_flags(VXF_HIDE_MOUNT, 0)) + return 0; + if (!mnt_is_reachable(mnt) && !vx_check(0, VS_WATCH_P)) + return 0; + + if (!vx_check(0, VS_ADMIN|VS_WATCH) && + mnt == current->fs->rootmnt) { + seq_puts(m, "device /dev/root mounted on / "); + } else { + /* device */ + 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 "); + seq_path(m, mnt, mnt->mnt_root, " \t\n\\"); + seq_putc(m, ' '); + } + + /* file system type */ + seq_puts(m, "with fstype "); + mangle(m, mnt->mnt_sb->s_type->name); + + /* optional statistics */ + if (mnt->mnt_sb->s_op->show_stats) { + seq_putc(m, ' '); + err = mnt->mnt_sb->s_op->show_stats(m, mnt); + } + + seq_putc(m, '\n'); + return err; +} + +struct seq_operations mountstats_op = { + .start = m_start, + .next = m_next, + .stop = m_stop, + .show = show_vfsstat, +}; + +/** + * may_umount_tree - check if a mount tree is busy + * @mnt: root of mount tree + * + * This is called to check if a tree of mounts has any + * open files, pwds, chroots or sub mounts that are + * busy. + */ +int may_umount_tree(struct vfsmount *mnt) +{ + int actual_refs = 0; + int minimum_refs = 0; + struct vfsmount *p; + + spin_lock(&vfsmount_lock); + for (p = mnt; p; p = next_mnt(p, mnt)) { + actual_refs += atomic_read(&p->mnt_count); + minimum_refs += 2; + } + spin_unlock(&vfsmount_lock); + + if (actual_refs > minimum_refs) + return 0; + + return 1; +} + +EXPORT_SYMBOL(may_umount_tree); + +/** + * may_umount - check if a mount point is busy + * @mnt: root of mount + * + * This is called to check if a mount point has any + * open files, pwds, chroots or sub mounts. If the + * mount has sub mounts this will return busy + * regardless of whether the sub mounts are busy. + * * Doesn't take quota and stuff into account. IOW, in some cases it will * give false negatives. The main reason why it's here is that we need * a non-destructive way to look for easily umountable filesystems. */ int may_umount(struct vfsmount *mnt) { - if (atomic_read(&mnt->mnt_count) > 2) - return -EBUSY; - return 0; + int ret = 1; + spin_lock(&vfsmount_lock); + if (propagate_mount_busy(mnt, 2)) + ret = 0; + spin_unlock(&vfsmount_lock); + return ret; } EXPORT_SYMBOL(may_umount); -static inline void __umount_tree(struct vfsmount *mnt, struct list_head *kill) +void release_mounts(struct list_head *head) { - while (!list_empty(kill)) { - mnt = list_entry(kill->next, struct vfsmount, mnt_list); - list_del_init(&mnt->mnt_list); - if (mnt->mnt_parent == mnt) { - spin_unlock(&vfsmount_lock); - } else { - struct nameidata old_nd; - detach_mnt(mnt, &old_nd); + struct vfsmount *mnt; + while (!list_empty(head)) { + mnt = list_entry(head->next, struct vfsmount, mnt_hash); + list_del_init(&mnt->mnt_hash); + if (mnt->mnt_parent != mnt) { + struct dentry *dentry; + struct vfsmount *m; + spin_lock(&vfsmount_lock); + dentry = mnt->mnt_mountpoint; + m = mnt->mnt_parent; + mnt->mnt_mountpoint = mnt->mnt_root; + mnt->mnt_parent = mnt; spin_unlock(&vfsmount_lock); - path_release(&old_nd); + dput(dentry); + mntput(m); } mntput(mnt); - spin_lock(&vfsmount_lock); } } -void umount_tree(struct vfsmount *mnt) +void umount_tree(struct vfsmount *mnt, int propagate, struct list_head *kill) { struct vfsmount *p; - LIST_HEAD(kill); - for (p = mnt; p; p = next_mnt(p, mnt)) { - list_del(&p->mnt_list); - list_add(&p->mnt_list, &kill); + for (p = mnt; p; p = next_mnt(p, mnt)) + list_move(&p->mnt_hash, kill); + + if (propagate) + propagate_umount(kill); + + list_for_each_entry(p, kill, mnt_hash) { + list_del_init(&p->mnt_expire); + list_del_init(&p->mnt_list); + __touch_mnt_namespace(p->mnt_ns); + p->mnt_ns = NULL; + list_del_init(&p->mnt_child); + if (p->mnt_parent != p) + p->mnt_mountpoint->d_mounted--; + change_mnt_propagation(p, MS_PRIVATE); } - __umount_tree(mnt, &kill); -} - -void umount_unused(struct vfsmount *mnt, struct fs_struct *fs) -{ - struct vfsmount *p; - LIST_HEAD(kill); - - for (p = mnt; p; p = next_mnt(p, mnt)) { - if (p == fs->rootmnt || p == fs->pwdmnt) - continue; - list_del(&p->mnt_list); - list_add(&p->mnt_list, &kill); - } - __umount_tree(mnt, &kill); } static int do_umount(struct vfsmount *mnt, int flags) { - struct super_block * sb = mnt->mnt_sb; + struct super_block *sb = mnt->mnt_sb; int retval; + LIST_HEAD(umount_list); retval = security_sb_umount(mnt, flags); if (retval) return retval; + /* + * Allow userspace to request a mountpoint be expired rather than + * unmounting unconditionally. Unmount only happens if: + * (1) the mark is already set (the mark is cleared by mntput()) + * (2) the usage count == 1 [parent vfsmount] + 1 [sys_umount] + */ + if (flags & MNT_EXPIRE) { + if (mnt == current->fs->rootmnt || + flags & (MNT_FORCE | MNT_DETACH)) + return -EINVAL; + + if (atomic_read(&mnt->mnt_count) != 2) + return -EBUSY; + + if (!xchg(&mnt->mnt_expiry_mark, 1)) + return -EAGAIN; + } + /* * If we may have to abort operations to get out of this * mount, and they will themselves hold resources we must @@ -340,8 +633,8 @@ static int do_umount(struct vfsmount *mnt, int flags) */ lock_kernel(); - if( (flags&MNT_FORCE) && sb->s_op->umount_begin) - sb->s_op->umount_begin(sb); + if (sb->s_op->umount_begin) + sb->s_op->umount_begin(mnt, flags); unlock_kernel(); /* @@ -361,36 +654,29 @@ static int do_umount(struct vfsmount *mnt, int flags) down_write(&sb->s_umount); if (!(sb->s_flags & MS_RDONLY)) { lock_kernel(); - retval = do_remount_sb(sb, MS_RDONLY, 0, 0); + DQUOT_OFF(sb); + retval = do_remount_sb(sb, MS_RDONLY, NULL, 0); unlock_kernel(); } up_write(&sb->s_umount); return retval; } - down_write(¤t->namespace->sem); + down_write(&namespace_sem); spin_lock(&vfsmount_lock); + event++; - if (atomic_read(&sb->s_active) == 1) { - /* last instance - try to be smart */ - spin_unlock(&vfsmount_lock); - lock_kernel(); - DQUOT_OFF(sb); - acct_auto_close(sb); - unlock_kernel(); - security_sb_umount_close(mnt); - spin_lock(&vfsmount_lock); - } retval = -EBUSY; - if (atomic_read(&mnt->mnt_count) == 2 || flags & MNT_DETACH) { + if (flags & MNT_DETACH || !propagate_mount_busy(mnt, 2)) { if (!list_empty(&mnt->mnt_list)) - umount_tree(mnt); + umount_tree(mnt, 1, &umount_list); retval = 0; } spin_unlock(&vfsmount_lock); if (retval) security_sb_umount_busy(mnt); - up_write(¤t->namespace->sem); + up_write(&namespace_sem); + release_mounts(&umount_list); return retval; } @@ -417,30 +703,31 @@ asmlinkage long sys_umount(char __user * name, int flags) goto dput_and_out; retval = -EPERM; - if (!capable(CAP_SYS_ADMIN) && !vx_ccaps(VXC_SECURE_MOUNT)) + if (!vx_capable(CAP_SYS_ADMIN, VXC_SECURE_MOUNT)) goto dput_and_out; retval = do_umount(nd.mnt, flags); dput_and_out: - path_release(&nd); + path_release_on_umount(&nd); out: return retval; } +#ifdef __ARCH_WANT_SYS_OLDUMOUNT + /* - * The 2.0 compatible umount. No flags. + * The 2.0 compatible umount. No flags. */ - asmlinkage long sys_oldumount(char __user * name) { - return sys_umount(name,0); + return sys_umount(name, 0); } +#endif + static int mount_is_safe(struct nameidata *nd) { - if (capable(CAP_SYS_ADMIN)) - return 0; - if (vx_ccaps(VXC_SECURE_MOUNT)) + if (vx_capable(CAP_SYS_ADMIN, VXC_SECURE_MOUNT)) return 0; return -EPERM; #ifdef notyet @@ -450,14 +737,13 @@ static int mount_is_safe(struct nameidata *nd) if (current->uid != nd->dentry->d_inode->i_uid) return -EPERM; } - if (permission(nd->dentry->d_inode, MAY_WRITE, nd)) + if (vfs_permission(nd, MAY_WRITE)) return -EPERM; return 0; #endif } -static int -lives_below_in_same_fs(struct dentry *d, struct dentry *dentry) +static int lives_below_in_same_fs(struct dentry *d, struct dentry *dentry) { while (1) { if (d == dentry) @@ -468,24 +754,30 @@ lives_below_in_same_fs(struct dentry *d, struct dentry *dentry) } } -static struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry) +struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry, + int flag) { struct vfsmount *res, *p, *q, *r, *s; - struct list_head *h; struct nameidata nd; - res = q = clone_mnt(mnt, dentry); + if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(mnt)) + return NULL; + + res = q = clone_mnt(mnt, dentry, flag); if (!q) goto Enomem; q->mnt_mountpoint = mnt->mnt_mountpoint; p = mnt; - for (h = mnt->mnt_mounts.next; h != &mnt->mnt_mounts; h = h->next) { - r = list_entry(h, struct vfsmount, mnt_child); + list_for_each_entry(r, &mnt->mnt_mounts, mnt_child) { if (!lives_below_in_same_fs(r->mnt_mountpoint, dentry)) continue; for (s = r; s; s = next_mnt(s, r)) { + if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(s)) { + s = skip_mnt_tree(s); + continue; + } while (p != s->mnt_parent) { p = p->mnt_parent; q = q->mnt_parent; @@ -493,7 +785,7 @@ static struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry) p = s; nd.mnt = q; nd.dentry = p->mnt_mountpoint; - q = clone_mnt(p, p->mnt_root); + q = clone_mnt(p, p->mnt_root, flag); if (!q) goto Enomem; spin_lock(&vfsmount_lock); @@ -503,15 +795,114 @@ static struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry) } } return res; - Enomem: +Enomem: if (res) { + LIST_HEAD(umount_list); spin_lock(&vfsmount_lock); - umount_tree(res); + umount_tree(res, 0, &umount_list); spin_unlock(&vfsmount_lock); + release_mounts(&umount_list); } return NULL; } +/* + * @source_mnt : mount tree to be attached + * @nd : place the mount tree @source_mnt is attached + * @parent_nd : if non-null, detach the source_mnt from its parent and + * store the parent mount and mountpoint dentry. + * (done when source_mnt is moved) + * + * NOTE: in the table below explains the semantics when a source mount + * of a given type is attached to a destination mount of a given type. + * --------------------------------------------------------------------------- + * | BIND MOUNT OPERATION | + * |************************************************************************** + * | source-->| shared | private | slave | unbindable | + * | dest | | | | | + * | | | | | | | + * | v | | | | | + * |************************************************************************** + * | shared | shared (++) | shared (+) | shared(+++)| invalid | + * | | | | | | + * |non-shared| shared (+) | private | slave (*) | invalid | + * *************************************************************************** + * A bind operation clones the source mount and mounts the clone on the + * destination mount. + * + * (++) the cloned mount is propagated to all the mounts in the propagation + * tree of the destination mount and the cloned mount is added to + * the peer group of the source mount. + * (+) the cloned mount is created under the destination mount and is marked + * as shared. The cloned mount is added to the peer group of the source + * mount. + * (+++) the mount is propagated to all the mounts in the propagation tree + * of the destination mount and the cloned mount is made slave + * of the same master as that of the source mount. The cloned mount + * is marked as 'shared and slave'. + * (*) the cloned mount is made a slave of the same master as that of the + * source mount. + * + * --------------------------------------------------------------------------- + * | MOVE MOUNT OPERATION | + * |************************************************************************** + * | source-->| shared | private | slave | unbindable | + * | dest | | | | | + * | | | | | | | + * | v | | | | | + * |************************************************************************** + * | shared | shared (+) | shared (+) | shared(+++) | invalid | + * | | | | | | + * |non-shared| shared (+*) | private | slave (*) | unbindable | + * *************************************************************************** + * + * (+) the mount is moved to the destination. And is then propagated to + * all the mounts in the propagation tree of the destination mount. + * (+*) the mount is moved to the destination. + * (+++) the mount is moved to the destination and is then propagated to + * all the mounts belonging to the destination mount's propagation tree. + * the mount is marked as 'shared and slave'. + * (*) the mount continues to be a slave at the new location. + * + * if the source mount is a tree, the operations explained above is + * applied to each mount in the tree. + * Must be called without spinlocks held, since this function can sleep + * in allocations. + */ +static int attach_recursive_mnt(struct vfsmount *source_mnt, + struct nameidata *nd, struct nameidata *parent_nd) +{ + LIST_HEAD(tree_list); + struct vfsmount *dest_mnt = nd->mnt; + struct dentry *dest_dentry = nd->dentry; + struct vfsmount *child, *p; + + if (propagate_mnt(dest_mnt, dest_dentry, source_mnt, &tree_list)) + return -EINVAL; + + if (IS_MNT_SHARED(dest_mnt)) { + for (p = source_mnt; p; p = next_mnt(p, source_mnt)) + set_mnt_shared(p); + } + + spin_lock(&vfsmount_lock); + if (parent_nd) { + detach_mnt(source_mnt, parent_nd); + attach_mnt(source_mnt, nd); + touch_mnt_namespace(current->nsproxy->mnt_ns); + } else { + mnt_set_mountpoint(dest_mnt, dest_dentry, source_mnt); + commit_tree(source_mnt); + } + + list_for_each_entry_safe(child, p, &tree_list, mnt_hash) { + list_del_init(&child->mnt_hash); + commit_tree(child); + } + spin_unlock(&vfsmount_lock); + return 0; +} + static int graft_tree(struct vfsmount *mnt, struct nameidata *nd) { int err; @@ -523,7 +914,7 @@ static int graft_tree(struct vfsmount *mnt, struct nameidata *nd) return -ENOTDIR; err = -ENOENT; - down(&nd->dentry->d_inode->i_sem); + mutex_lock(&nd->dentry->d_inode->i_mutex); if (IS_DEADDIR(nd->dentry->d_inode)) goto out_unlock; @@ -532,32 +923,46 @@ static int graft_tree(struct vfsmount *mnt, struct nameidata *nd) goto out_unlock; err = -ENOENT; - spin_lock(&vfsmount_lock); - if (IS_ROOT(nd->dentry) || !d_unhashed(nd->dentry)) { - struct list_head head; - - attach_mnt(mnt, nd); - list_add_tail(&head, &mnt->mnt_list); - list_splice(&head, current->namespace->list.prev); - mntget(mnt); - err = 0; - } - spin_unlock(&vfsmount_lock); + if (IS_ROOT(nd->dentry) || !d_unhashed(nd->dentry)) + err = attach_recursive_mnt(mnt, nd, NULL); out_unlock: - up(&nd->dentry->d_inode->i_sem); + mutex_unlock(&nd->dentry->d_inode->i_mutex); if (!err) security_sb_post_addmount(mnt, nd); return err; } +/* + * recursively change the type of the mountpoint. + */ +static int do_change_type(struct nameidata *nd, int flag) +{ + struct vfsmount *m, *mnt = nd->mnt; + int recurse = flag & MS_REC; + int type = flag & ~MS_REC; + + if (nd->dentry != nd->mnt->mnt_root) + return -EINVAL; + + down_write(&namespace_sem); + spin_lock(&vfsmount_lock); + for (m = mnt; m; m = (recurse ? next_mnt(m, mnt) : NULL)) + change_mnt_propagation(m, type); + spin_unlock(&vfsmount_lock); + up_write(&namespace_sem); + return 0; +} + /* * do loopback mount. */ -static int do_loopback(struct nameidata *nd, char *old_name, int recurse) +static int do_loopback(struct nameidata *nd, char *old_name, tag_t tag, + unsigned long flags, int mnt_flags) { struct nameidata old_nd; struct vfsmount *mnt = NULL; int err = mount_is_safe(nd); + int recurse = flags & MS_REC; if (err) return err; if (!old_name || !*old_name) @@ -566,27 +971,41 @@ static int do_loopback(struct nameidata *nd, char *old_name, int recurse) if (err) return err; - down_write(¤t->namespace->sem); + down_write(&namespace_sem); err = -EINVAL; - if (check_mnt(nd->mnt) && (!recurse || check_mnt(old_nd.mnt))) { - err = -ENOMEM; - if (recurse) - mnt = copy_tree(old_nd.mnt, old_nd.dentry); - else - mnt = clone_mnt(old_nd.mnt, old_nd.dentry); + if (IS_MNT_UNBINDABLE(old_nd.mnt)) + goto out; + + if (!check_mnt(nd->mnt) || !check_mnt(old_nd.mnt)) + goto out; + + err = -ENOMEM; + if (recurse) + mnt = copy_tree(old_nd.mnt, old_nd.dentry, 0); + else + mnt = clone_mnt(old_nd.mnt, old_nd.dentry, 0); + + if (!mnt) + goto out; + + mnt->mnt_flags = mnt_flags; + if (flags & MS_TAGID) { + mnt->mnt_tag = tag; + mnt->mnt_flags |= MNT_TAGID; } - if (mnt) { - err = graft_tree(mnt, nd); - if (err) { - spin_lock(&vfsmount_lock); - umount_tree(mnt); - spin_unlock(&vfsmount_lock); - } else - mntput(mnt); + err = graft_tree(mnt, nd); + if (err) { + LIST_HEAD(umount_list); + spin_lock(&vfsmount_lock); + umount_tree(mnt, 0, &umount_list); + spin_unlock(&vfsmount_lock); + release_mounts(&umount_list); } + mnt->mnt_flags = mnt_flags; - up_write(¤t->namespace->sem); +out: + up_write(&namespace_sem); path_release(&old_nd); return err; } @@ -596,13 +1015,13 @@ static int do_loopback(struct nameidata *nd, char *old_name, int recurse) * If you've mounted a non-root directory somewhere and want to do remount * on it - tough luck. */ - -static int do_remount(struct nameidata *nd,int flags,int mnt_flags,void *data) +static int do_remount(struct nameidata *nd, int flags, int mnt_flags, + void *data, xid_t xid) { int err; - struct super_block * sb = nd->mnt->mnt_sb; + struct super_block *sb = nd->mnt->mnt_sb; - if (!capable(CAP_SYS_ADMIN)) + if (!vx_capable(CAP_SYS_ADMIN, VXC_SECURE_REMOUNT)) return -EPERM; if (!check_mnt(nd->mnt)) @@ -614,19 +1033,29 @@ static int do_remount(struct nameidata *nd,int flags,int mnt_flags,void *data) down_write(&sb->s_umount); err = do_remount_sb(sb, flags, data, 0); if (!err) - nd->mnt->mnt_flags=mnt_flags; + nd->mnt->mnt_flags = mnt_flags; up_write(&sb->s_umount); if (!err) security_sb_post_remount(nd->mnt, flags, data); return err; } +static inline int tree_contains_unbindable(struct vfsmount *mnt) +{ + struct vfsmount *p; + for (p = mnt; p; p = next_mnt(p, mnt)) { + if (IS_MNT_UNBINDABLE(p)) + return 1; + } + return 0; +} + static int do_move_mount(struct nameidata *nd, char *old_name) { struct nameidata old_nd, parent_nd; struct vfsmount *p; int err = 0; - if (!capable(CAP_SYS_ADMIN)) + if (!vx_capable(CAP_SYS_ADMIN, VXC_SECURE_MOUNT)) return -EPERM; if (!old_name || !*old_name) return -EINVAL; @@ -634,74 +1063,100 @@ static int do_move_mount(struct nameidata *nd, char *old_name) if (err) return err; - down_write(¤t->namespace->sem); - while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry)) + down_write(&namespace_sem); + while (d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry)) ; err = -EINVAL; if (!check_mnt(nd->mnt) || !check_mnt(old_nd.mnt)) goto out; err = -ENOENT; - down(&nd->dentry->d_inode->i_sem); + mutex_lock(&nd->dentry->d_inode->i_mutex); if (IS_DEADDIR(nd->dentry->d_inode)) goto out1; - spin_lock(&vfsmount_lock); if (!IS_ROOT(nd->dentry) && d_unhashed(nd->dentry)) - goto out2; + goto out1; err = -EINVAL; if (old_nd.dentry != old_nd.mnt->mnt_root) - goto out2; + goto out1; if (old_nd.mnt == old_nd.mnt->mnt_parent) - goto out2; + goto out1; if (S_ISDIR(nd->dentry->d_inode->i_mode) != S_ISDIR(old_nd.dentry->d_inode->i_mode)) - goto out2; - + goto out1; + /* + * Don't move a mount residing in a shared parent. + */ + if (old_nd.mnt->mnt_parent && IS_MNT_SHARED(old_nd.mnt->mnt_parent)) + goto out1; + /* + * Don't move a mount tree containing unbindable mounts to a destination + * mount which is shared. + */ + if (IS_MNT_SHARED(nd->mnt) && tree_contains_unbindable(old_nd.mnt)) + goto out1; err = -ELOOP; - for (p = nd->mnt; p->mnt_parent!=p; p = p->mnt_parent) + for (p = nd->mnt; p->mnt_parent != p; p = p->mnt_parent) if (p == old_nd.mnt) - goto out2; - err = 0; + goto out1; - detach_mnt(old_nd.mnt, &parent_nd); - attach_mnt(old_nd.mnt, nd); -out2: + if ((err = attach_recursive_mnt(old_nd.mnt, nd, &parent_nd))) + goto out1; + + spin_lock(&vfsmount_lock); + /* if the mount is moved, it should no longer be expire + * automatically */ + list_del_init(&old_nd.mnt->mnt_expire); spin_unlock(&vfsmount_lock); out1: - up(&nd->dentry->d_inode->i_sem); + mutex_unlock(&nd->dentry->d_inode->i_mutex); out: - up_write(¤t->namespace->sem); + up_write(&namespace_sem); if (!err) path_release(&parent_nd); path_release(&old_nd); return err; } -static int do_add_mount(struct nameidata *nd, char *type, int flags, +/* + * create a new mount for userspace and request it to be added into the + * namespace's tree + */ +static int do_new_mount(struct nameidata *nd, char *type, int flags, int mnt_flags, char *name, void *data) { struct vfsmount *mnt; - int err; if (!type || !memchr(type, 0, PAGE_SIZE)) return -EINVAL; /* we need capabilities... */ - if (!capable(CAP_SYS_ADMIN)) + if (!vx_capable(CAP_SYS_ADMIN, VXC_SECURE_MOUNT)) return -EPERM; mnt = do_kern_mount(type, flags, name, data); - err = PTR_ERR(mnt); if (IS_ERR(mnt)) - goto out; + return PTR_ERR(mnt); + + return do_add_mount(mnt, nd, mnt_flags, NULL); +} + +/* + * add a mount into a namespace's mount tree + * - provide the option of adding the new mount to an expiration list + */ +int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd, + int mnt_flags, struct list_head *fslist) +{ + int err; - down_write(¤t->namespace->sem); + down_write(&namespace_sem); /* Something was mounted here while we slept */ - while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry)) + while (d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry)) ; err = -EINVAL; if (!check_mnt(nd->mnt)) @@ -709,28 +1164,242 @@ static int do_add_mount(struct nameidata *nd, char *type, int flags, /* Refuse the same filesystem on the same mount point */ err = -EBUSY; - if (nd->mnt->mnt_sb == mnt->mnt_sb && nd->mnt->mnt_root == nd->dentry) + if (nd->mnt->mnt_sb == newmnt->mnt_sb && + nd->mnt->mnt_root == nd->dentry) goto unlock; err = -EINVAL; - if (S_ISLNK(mnt->mnt_root->d_inode->i_mode)) + if (S_ISLNK(newmnt->mnt_root->d_inode->i_mode)) goto unlock; - mnt->mnt_flags = mnt_flags; - err = graft_tree(mnt, nd); + newmnt->mnt_flags = mnt_flags; + if ((err = graft_tree(newmnt, nd))) + goto unlock; + + if (fslist) { + /* add to the specified expiration list */ + spin_lock(&vfsmount_lock); + list_add_tail(&newmnt->mnt_expire, fslist); + spin_unlock(&vfsmount_lock); + } + up_write(&namespace_sem); + return 0; + unlock: - up_write(¤t->namespace->sem); - mntput(mnt); -out: + up_write(&namespace_sem); + mntput(newmnt); return err; } -int copy_mount_options (const void __user *data, unsigned long *where) +EXPORT_SYMBOL_GPL(do_add_mount); + +static void expire_mount(struct vfsmount *mnt, struct list_head *mounts, + struct list_head *umounts) +{ + spin_lock(&vfsmount_lock); + + /* + * Check if mount is still attached, if not, let whoever holds it deal + * with the sucker + */ + if (mnt->mnt_parent == mnt) { + spin_unlock(&vfsmount_lock); + return; + } + + /* + * Check that it is still dead: the count should now be 2 - as + * contributed by the vfsmount parent and the mntget above + */ + if (!propagate_mount_busy(mnt, 2)) { + /* delete from the namespace */ + touch_mnt_namespace(mnt->mnt_ns); + list_del_init(&mnt->mnt_list); + mnt->mnt_ns = NULL; + umount_tree(mnt, 1, umounts); + spin_unlock(&vfsmount_lock); + } else { + /* + * Someone brought it back to life whilst we didn't have any + * locks held so return it to the expiration list + */ + list_add_tail(&mnt->mnt_expire, mounts); + spin_unlock(&vfsmount_lock); + } +} + +/* + * go through the vfsmounts we've just consigned to the graveyard to + * - check that they're still dead + * - delete the vfsmount from the appropriate namespace under lock + * - dispose of the corpse + */ +static void expire_mount_list(struct list_head *graveyard, struct list_head *mounts) +{ + struct mnt_namespace *ns; + struct vfsmount *mnt; + + while (!list_empty(graveyard)) { + LIST_HEAD(umounts); + mnt = list_entry(graveyard->next, struct vfsmount, mnt_expire); + list_del_init(&mnt->mnt_expire); + + /* don't do anything if the namespace is dead - all the + * vfsmounts from it are going away anyway */ + ns = mnt->mnt_ns; + if (!ns || !ns->root) + continue; + get_mnt_ns(ns); + + spin_unlock(&vfsmount_lock); + down_write(&namespace_sem); + expire_mount(mnt, mounts, &umounts); + up_write(&namespace_sem); + release_mounts(&umounts); + mntput(mnt); + put_mnt_ns(ns); + spin_lock(&vfsmount_lock); + } +} + +/* + * process a list of expirable mountpoints with the intent of discarding any + * mountpoints that aren't in use and haven't been touched since last we came + * here + */ +void mark_mounts_for_expiry(struct list_head *mounts) +{ + struct vfsmount *mnt, *next; + LIST_HEAD(graveyard); + + if (list_empty(mounts)) + return; + + spin_lock(&vfsmount_lock); + + /* extract from the expiration list every vfsmount that matches the + * following criteria: + * - only referenced by its parent vfsmount + * - still marked for expiry (marked on the last call here; marks are + * cleared by mntput()) + */ + list_for_each_entry_safe(mnt, next, mounts, mnt_expire) { + if (!xchg(&mnt->mnt_expiry_mark, 1) || + atomic_read(&mnt->mnt_count) != 1) + continue; + + mntget(mnt); + list_move(&mnt->mnt_expire, &graveyard); + } + + expire_mount_list(&graveyard, mounts); + + spin_unlock(&vfsmount_lock); +} + +EXPORT_SYMBOL_GPL(mark_mounts_for_expiry); + +/* + * Ripoff of 'select_parent()' + * + * search the list of submounts for a given mountpoint, and move any + * shrinkable submounts to the 'graveyard' list. + */ +static int select_submounts(struct vfsmount *parent, struct list_head *graveyard) +{ + struct vfsmount *this_parent = parent; + struct list_head *next; + int found = 0; + +repeat: + next = this_parent->mnt_mounts.next; +resume: + while (next != &this_parent->mnt_mounts) { + struct list_head *tmp = next; + struct vfsmount *mnt = list_entry(tmp, struct vfsmount, mnt_child); + + next = tmp->next; + if (!(mnt->mnt_flags & MNT_SHRINKABLE)) + continue; + /* + * Descend a level if the d_mounts list is non-empty. + */ + if (!list_empty(&mnt->mnt_mounts)) { + this_parent = mnt; + goto repeat; + } + + if (!propagate_mount_busy(mnt, 1)) { + mntget(mnt); + list_move_tail(&mnt->mnt_expire, graveyard); + found++; + } + } + /* + * All done at this level ... ascend and resume the search + */ + if (this_parent != parent) { + next = this_parent->mnt_child.next; + this_parent = this_parent->mnt_parent; + goto resume; + } + return found; +} + +/* + * process a list of expirable mountpoints with the intent of discarding any + * submounts of a specific parent mountpoint + */ +void shrink_submounts(struct vfsmount *mountpoint, struct list_head *mounts) +{ + LIST_HEAD(graveyard); + int found; + + spin_lock(&vfsmount_lock); + + /* extract submounts of 'mountpoint' from the expiration list */ + while ((found = select_submounts(mountpoint, &graveyard)) != 0) + expire_mount_list(&graveyard, mounts); + + spin_unlock(&vfsmount_lock); +} + +EXPORT_SYMBOL_GPL(shrink_submounts); + +/* + * Some copy_from_user() implementations do not return the exact number of + * bytes remaining to copy on a fault. But copy_mount_options() requires that. + * Note that this function differs from copy_from_user() in that it will oops + * on bad values of `to', rather than returning a short copy. + */ +static long exact_copy_from_user(void *to, const void __user * from, + unsigned long n) +{ + char *t = to; + const char __user *f = from; + char c; + + if (!access_ok(VERIFY_READ, from, n)) + return n; + + while (n) { + if (__get_user(c, f)) { + memset(t, 0, n); + break; + } + *t++ = c; + f++; + n--; + } + return n; +} + +int copy_mount_options(const void __user * data, unsigned long *where) { int i; unsigned long page; unsigned long size; - + *where = 0; if (!data) return 0; @@ -747,9 +1416,9 @@ int copy_mount_options (const void __user *data, unsigned long *where) if (size > PAGE_SIZE) size = PAGE_SIZE; - i = size - copy_from_user((void *)page, data, size); + i = size - exact_copy_from_user((void *)page, data, size); if (!i) { - free_page(page); + free_page(page); return -EFAULT; } if (i != PAGE_SIZE) @@ -772,12 +1441,13 @@ int copy_mount_options (const void __user *data, unsigned long *where) * Therefore, if this magic number is present, it carries no information * and must be discarded. */ -long do_mount(char * dev_name, char * dir_name, char *type_page, +long do_mount(char *dev_name, char *dir_name, char *type_page, unsigned long flags, void *data_page) { struct nameidata nd; int retval = 0; int mnt_flags = 0; + tag_t tag = 0; /* Discard magic */ if ((flags & MS_MGC_MSK) == MS_MGC_VAL) @@ -793,17 +1463,36 @@ long do_mount(char * dev_name, char * dir_name, char *type_page, if (data_page) ((char *)data_page)[PAGE_SIZE - 1] = 0; +#ifdef CONFIG_PROPAGATE + retval = dx_parse_tag(data_page, &tag, 1); + if (retval) { + mnt_flags |= MNT_TAGID; + /* bind and re-mounts get the tag flag */ + if (flags & (MS_BIND|MS_REMOUNT)) + flags |= MS_TAGID; + } +#endif + /* Separate the per-mountpoint flags */ + if (flags & MS_RDONLY) + mnt_flags |= MNT_RDONLY; if (flags & MS_NOSUID) mnt_flags |= MNT_NOSUID; if (flags & MS_NODEV) mnt_flags |= MNT_NODEV; if (flags & MS_NOEXEC) mnt_flags |= MNT_NOEXEC; - flags &= ~(MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_ACTIVE); + if (flags & MS_NOATIME) + mnt_flags |= MNT_NOATIME; + if (flags & MS_NODIRATIME) + mnt_flags |= MNT_NODIRATIME; + if (flags & MS_RELATIME) + mnt_flags |= MNT_RELATIME; - if (vx_ccaps(VXC_SECURE_MOUNT)) + if (!capable(CAP_SYS_ADMIN)) mnt_flags |= MNT_NODEV; + flags &= ~(MS_NOSUID | MS_NOEXEC | MS_NODEV | MS_ACTIVE | + MS_NOATIME | MS_NODIRATIME | MS_RELATIME); /* ... and get the mountpoint */ retval = path_lookup(dir_name, LOOKUP_FOLLOW, &nd); @@ -816,67 +1505,65 @@ long do_mount(char * dev_name, char * dir_name, char *type_page, if (flags & MS_REMOUNT) retval = do_remount(&nd, flags & ~MS_REMOUNT, mnt_flags, - data_page); + data_page, tag); else if (flags & MS_BIND) - retval = do_loopback(&nd, dev_name, flags & MS_REC); + retval = do_loopback(&nd, dev_name, tag, flags, mnt_flags); + else if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE)) + retval = do_change_type(&nd, flags); else if (flags & MS_MOVE) retval = do_move_mount(&nd, dev_name); else - retval = do_add_mount(&nd, type_page, flags, mnt_flags, + retval = do_new_mount(&nd, type_page, flags, mnt_flags, dev_name, data_page); dput_out: path_release(&nd); return retval; } -int copy_namespace(int flags, struct task_struct *tsk) +/* + * Allocate a new namespace structure and populate it with contents + * copied from the namespace of the passed in task structure. + */ +struct mnt_namespace *dup_mnt_ns(struct task_struct *tsk, + struct fs_struct *fs) { - struct namespace *namespace = tsk->namespace; - struct namespace *new_ns; + struct mnt_namespace *mnt_ns = tsk->nsproxy->mnt_ns; + struct mnt_namespace *new_ns; struct vfsmount *rootmnt = NULL, *pwdmnt = NULL, *altrootmnt = NULL; - struct fs_struct *fs = tsk->fs; - - if (!namespace) - return 0; + struct vfsmount *p, *q; - get_namespace(namespace); - - if (!(flags & CLONE_NEWNS)) - return 0; - - if (!capable(CAP_SYS_ADMIN)) { - put_namespace(namespace); - return -EPERM; - } - - new_ns = kmalloc(sizeof(struct namespace), GFP_KERNEL); + new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL); if (!new_ns) - goto out; + return NULL; atomic_set(&new_ns->count, 1); - init_rwsem(&new_ns->sem); INIT_LIST_HEAD(&new_ns->list); + init_waitqueue_head(&new_ns->poll); + new_ns->event = 0; - down_write(&tsk->namespace->sem); + down_write(&namespace_sem); /* First pass: copy the tree topology */ - new_ns->root = copy_tree(namespace->root, namespace->root->mnt_root); + new_ns->root = copy_tree(mnt_ns->root, mnt_ns->root->mnt_root, + CL_COPY_ALL | CL_EXPIRE); if (!new_ns->root) { - up_write(&tsk->namespace->sem); + up_write(&namespace_sem); kfree(new_ns); - goto out; + return NULL; } spin_lock(&vfsmount_lock); list_add_tail(&new_ns->list, &new_ns->root->mnt_list); spin_unlock(&vfsmount_lock); - /* Second pass: switch the tsk->fs->* elements */ - if (fs) { - struct vfsmount *p, *q; - write_lock(&fs->lock); - - p = namespace->root; - q = new_ns->root; - while (p) { + /* + * Second pass: switch the tsk->fs->* elements and mark new vfsmounts + * as belonging to new namespace. We have already acquired a private + * fs_struct, so tsk->fs->lock is not needed. + */ + p = mnt_ns->root; + q = new_ns->root; + while (p) { + q->mnt_ns = new_ns; + if (fs) { if (p == fs->rootmnt) { rootmnt = p; fs->rootmnt = mntget(q); @@ -889,14 +1576,12 @@ int copy_namespace(int flags, struct task_struct *tsk) altrootmnt = p; fs->altrootmnt = mntget(q); } - p = next_mnt(p, namespace->root); - q = next_mnt(q, new_ns->root); } - write_unlock(&fs->lock); + p = next_mnt(p, mnt_ns->root); + q = next_mnt(q, new_ns->root); } - up_write(&tsk->namespace->sem); - - tsk->namespace = new_ns; + up_write(&namespace_sem); + atomic_inc(&vs_global_mnt_ns); if (rootmnt) mntput(rootmnt); @@ -905,12 +1590,39 @@ int copy_namespace(int flags, struct task_struct *tsk) if (altrootmnt) mntput(altrootmnt); - put_namespace(namespace); - return 0; + return new_ns; +} + +int copy_mnt_ns(int flags, struct task_struct *tsk) +{ + struct mnt_namespace *ns = tsk->nsproxy->mnt_ns; + struct mnt_namespace *new_ns; + int err = 0; + + if (!ns) + return 0; + + get_mnt_ns(ns); + + if (!(flags & CLONE_NEWNS)) + return 0; + + if (!vx_capable(CAP_SYS_ADMIN, VXC_SECURE_MOUNT)) { + err = -EPERM; + goto out; + } + + new_ns = dup_mnt_ns(tsk, tsk->fs); + if (!new_ns) { + err = -ENOMEM; + goto out; + } + + tsk->nsproxy->mnt_ns = new_ns; out: - put_namespace(namespace); - return -ENOMEM; + put_mnt_ns(ns); + return err; } asmlinkage long sys_mount(char __user * dev_name, char __user * dir_name, @@ -923,7 +1635,7 @@ asmlinkage long sys_mount(char __user * dev_name, char __user * dir_name, unsigned long dev_page; char *dir_page; - retval = copy_mount_options (type, &type_page); + retval = copy_mount_options(type, &type_page); if (retval < 0) return retval; @@ -932,17 +1644,17 @@ asmlinkage long sys_mount(char __user * dev_name, char __user * dir_name, if (IS_ERR(dir_page)) goto out1; - retval = copy_mount_options (dev_name, &dev_page); + retval = copy_mount_options(dev_name, &dev_page); if (retval < 0) goto out2; - retval = copy_mount_options (data, &data_page); + retval = copy_mount_options(data, &data_page); if (retval < 0) goto out3; lock_kernel(); - retval = do_mount((char*)dev_page, dir_page, (char*)type_page, - flags, (void*)data_page); + retval = do_mount((char *)dev_page, dir_page, (char *)type_page, + flags, (void *)data_page); unlock_kernel(); free_page(data_page); @@ -976,8 +1688,6 @@ void set_fs_root(struct fs_struct *fs, struct vfsmount *mnt, } } -EXPORT_SYMBOL(set_fs_root); - /* * Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values. * It can block. Requires the big lock held. @@ -1001,8 +1711,6 @@ void set_fs_pwd(struct fs_struct *fs, struct vfsmount *mnt, } } -EXPORT_SYMBOL(set_fs_pwd); - static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd) { struct task_struct *g, *p; @@ -1015,9 +1723,11 @@ static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd) if (fs) { atomic_inc(&fs->count); task_unlock(p); - if (fs->root==old_nd->dentry&&fs->rootmnt==old_nd->mnt) + if (fs->root == old_nd->dentry + && fs->rootmnt == old_nd->mnt) set_fs_root(fs, new_nd->mnt, new_nd->dentry); - if (fs->pwd==old_nd->dentry&&fs->pwdmnt==old_nd->mnt) + if (fs->pwd == old_nd->dentry + && fs->pwdmnt == old_nd->mnt) set_fs_pwd(fs, new_nd->mnt, new_nd->dentry); put_fs_struct(fs); } else @@ -1027,10 +1737,23 @@ static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd) } /* - * Moves the current root to put_root, and sets root/cwd of all processes - * which had them on the old root to new_root. + * pivot_root Semantics: + * Moves the root file system of the current process to the directory put_old, + * makes new_root as the new root file system of the current process, and sets + * root/cwd of all processes which had them on the current root to new_root. + * + * Restrictions: + * The new_root and put_old must be directories, and must not be on the + * same file system as the current process root. The put_old must be + * underneath new_root, i.e. adding a non-zero number of /.. to the string + * pointed to by put_old must yield the same directory as new_root. No other + * file system may be mounted on put_old. After all, new_root is a mountpoint. + * + * Also, the current root cannot be on the 'rootfs' (initial ramfs) filesystem. + * See Documentation/filesystems/ramfs-rootfs-initramfs.txt for alternatives + * in this situation. * - * Note: + * Notes: * - we don't move root/cwd if they are not at the root (reason: if something * cared enough to change them, it's probably wrong to force them elsewhere) * - it's okay to pick a root that isn't the root of a file system, e.g. @@ -1038,8 +1761,8 @@ static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd) * though, so you may need to say mount --bind /nfs/my_root /nfs/my_root * first. */ - -asmlinkage long sys_pivot_root(const char __user *new_root, const char __user *put_old) +asmlinkage long sys_pivot_root(const char __user * new_root, + const char __user * put_old) { struct vfsmount *tmp; struct nameidata new_nd, old_nd, parent_nd, root_parent, user_nd; @@ -1050,14 +1773,15 @@ asmlinkage long sys_pivot_root(const char __user *new_root, const char __user *p lock_kernel(); - error = __user_walk(new_root, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &new_nd); + error = __user_walk(new_root, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, + &new_nd); if (error) goto out0; error = -EINVAL; if (!check_mnt(new_nd.mnt)) goto out1; - error = __user_walk(put_old, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &old_nd); + error = __user_walk(put_old, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &old_nd); if (error) goto out1; @@ -1071,9 +1795,13 @@ asmlinkage long sys_pivot_root(const char __user *new_root, const char __user *p user_nd.mnt = mntget(current->fs->rootmnt); user_nd.dentry = dget(current->fs->root); read_unlock(¤t->fs->lock); - down_write(¤t->namespace->sem); - down(&old_nd.dentry->d_inode->i_sem); + down_write(&namespace_sem); + mutex_lock(&old_nd.dentry->d_inode->i_mutex); error = -EINVAL; + if (IS_MNT_SHARED(old_nd.mnt) || + IS_MNT_SHARED(new_nd.mnt->mnt_parent) || + IS_MNT_SHARED(user_nd.mnt->mnt_parent)) + goto out2; if (!check_mnt(user_nd.mnt)) goto out2; error = -ENOENT; @@ -1085,18 +1813,22 @@ asmlinkage long sys_pivot_root(const char __user *new_root, const char __user *p goto out2; error = -EBUSY; if (new_nd.mnt == user_nd.mnt || old_nd.mnt == user_nd.mnt) - goto out2; /* loop */ + goto out2; /* loop, on the same file system */ error = -EINVAL; if (user_nd.mnt->mnt_root != user_nd.dentry) - goto out2; + goto out2; /* not a mountpoint */ + if (user_nd.mnt->mnt_parent == user_nd.mnt) + goto out2; /* not attached */ if (new_nd.mnt->mnt_root != new_nd.dentry) goto out2; /* not a mountpoint */ + if (new_nd.mnt->mnt_parent == new_nd.mnt) + goto out2; /* not attached */ tmp = old_nd.mnt; /* make sure we can reach put_old from new_root */ spin_lock(&vfsmount_lock); if (tmp != new_nd.mnt) { for (;;) { if (tmp->mnt_parent == tmp) - goto out3; + goto out3; /* already mounted on put_old */ if (tmp->mnt_parent == new_nd.mnt) break; tmp = tmp->mnt_parent; @@ -1107,8 +1839,9 @@ asmlinkage long sys_pivot_root(const char __user *new_root, const char __user *p goto out3; detach_mnt(new_nd.mnt, &parent_nd); detach_mnt(user_nd.mnt, &root_parent); - attach_mnt(user_nd.mnt, &old_nd); - attach_mnt(new_nd.mnt, &root_parent); + attach_mnt(user_nd.mnt, &old_nd); /* mount old root on put_old */ + attach_mnt(new_nd.mnt, &root_parent); /* mount new_root on / */ + touch_mnt_namespace(current->nsproxy->mnt_ns); spin_unlock(&vfsmount_lock); chroot_fs_refs(&user_nd, &new_nd); security_sb_post_pivotroot(&user_nd, &new_nd); @@ -1116,8 +1849,8 @@ asmlinkage long sys_pivot_root(const char __user *new_root, const char __user *p path_release(&root_parent); path_release(&parent_nd); out2: - up(&old_nd.dentry->d_inode->i_sem); - up_write(¤t->namespace->sem); + mutex_unlock(&old_nd.dentry->d_inode->i_mutex); + up_write(&namespace_sem); path_release(&user_nd); path_release(&old_nd); out1: @@ -1133,48 +1866,42 @@ out3: static void __init init_mount_tree(void) { struct vfsmount *mnt; - struct namespace *namespace; - struct task_struct *g, *p; + struct mnt_namespace *ns; mnt = do_kern_mount("rootfs", 0, "rootfs", NULL); if (IS_ERR(mnt)) panic("Can't create rootfs"); - namespace = kmalloc(sizeof(*namespace), GFP_KERNEL); - if (!namespace) + ns = kmalloc(sizeof(*ns), GFP_KERNEL); + if (!ns) panic("Can't allocate initial namespace"); - atomic_set(&namespace->count, 1); - INIT_LIST_HEAD(&namespace->list); - init_rwsem(&namespace->sem); - list_add(&mnt->mnt_list, &namespace->list); - namespace->root = mnt; - - init_task.namespace = namespace; - read_lock(&tasklist_lock); - do_each_thread(g, p) { - get_namespace(namespace); - p->namespace = namespace; - } while_each_thread(g, p); - read_unlock(&tasklist_lock); - - set_fs_pwd(current->fs, namespace->root, namespace->root->mnt_root); - set_fs_root(current->fs, namespace->root, namespace->root->mnt_root); + 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); + + set_fs_pwd(current->fs, ns->root, ns->root->mnt_root); + set_fs_root(current->fs, ns->root, ns->root->mnt_root); } void __init mnt_init(unsigned long mempages) { struct list_head *d; - unsigned long order; unsigned int nr_hash; int i; + int err; + + init_rwsem(&namespace_sem); mnt_cache = kmem_cache_create("mnt_cache", sizeof(struct vfsmount), - 0, SLAB_HWCACHE_ALIGN, NULL, NULL); - if (!mnt_cache) - panic("Cannot create vfsmount cache"); + 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL, NULL); - order = 0; - mount_hashtable = (struct list_head *) - __get_free_pages(GFP_ATOMIC, order); + mount_hashtable = (struct list_head *)__get_free_page(GFP_ATOMIC); if (!mount_hashtable) panic("Failed to allocate mount hash table\n"); @@ -1184,7 +1911,7 @@ void __init mnt_init(unsigned long mempages) * We don't guarantee that "sizeof(struct list_head)" is necessarily * a power-of-two. */ - nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct list_head); + nr_hash = PAGE_SIZE / sizeof(struct list_head); hash_bits = 0; do { hash_bits++; @@ -1196,10 +1923,9 @@ void __init mnt_init(unsigned long mempages) * from the number of bits we can fit. */ nr_hash = 1UL << hash_bits; - hash_mask = nr_hash-1; + hash_mask = nr_hash - 1; - printk("Mount-cache hash table entries: %d (order: %ld, %ld bytes)\n", - nr_hash, order, (PAGE_SIZE << order)); + printk("Mount-cache hash table entries: %d\n", nr_hash); /* And initialize the newly allocated array */ d = mount_hashtable; @@ -1209,17 +1935,30 @@ void __init mnt_init(unsigned long mempages) d++; i--; } while (i); - sysfs_init(); + err = sysfs_init(); + if (err) + printk(KERN_WARNING "%s: sysfs_init error: %d\n", + __FUNCTION__, err); + err = subsystem_register(&fs_subsys); + if (err) + printk(KERN_WARNING "%s: subsystem_register error: %d\n", + __FUNCTION__, err); init_rootfs(); init_mount_tree(); } -void __put_namespace(struct namespace *namespace) +void __put_mnt_ns(struct mnt_namespace *ns) { - down_write(&namespace->sem); + struct vfsmount *root = ns->root; + LIST_HEAD(umount_list); + ns->root = NULL; + spin_unlock(&vfsmount_lock); + down_write(&namespace_sem); spin_lock(&vfsmount_lock); - umount_tree(namespace->root); + umount_tree(root, 0, &umount_list); spin_unlock(&vfsmount_lock); - up_write(&namespace->sem); - kfree(namespace); + up_write(&namespace_sem); + release_mounts(&umount_list); + atomic_dec(&vs_global_mnt_ns); + kfree(ns); }