* Heavily rewritten.
*/
-#include <linux/config.h>
#include <linux/syscalls.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
-#include <linux/quotaops.h>
+#include <linux/kernel.h>
#include <linux/acct.h>
+#include <linux/capability.h>
+#include <linux/cpumask.h>
#include <linux/module.h>
+#include <linux/sysfs.h>
#include <linux/seq_file.h>
-#include <linux/namespace.h>
+#include <linux/mnt_namespace.h>
#include <linux/namei.h>
#include <linux/security.h>
#include <linux/mount.h>
+#include <linux/ramfs.h>
+#include <linux/log2.h>
+#include <linux/idr.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include "pnode.h"
+#include "internal.h"
-extern int __init init_rootfs(void);
-
-#define CL_EXPIRE 0x01
-
-#ifdef CONFIG_SYSFS
-extern int __init sysfs_init(void);
-#else
-static inline int sysfs_init(void)
-{
- return 0;
-}
-#endif
+#define HASH_SHIFT ilog2(PAGE_SIZE / sizeof(struct list_head))
+#define HASH_SIZE (1UL << HASH_SHIFT)
/* spinlock for vfsmount related operations, inplace of dcache_lock */
__cacheline_aligned_in_smp DEFINE_SPINLOCK(vfsmount_lock);
static int event;
+static DEFINE_IDA(mnt_id_ida);
+static DEFINE_IDA(mnt_group_ida);
-static struct list_head *mount_hashtable;
-static int hash_mask __read_mostly, hash_bits __read_mostly;
-static kmem_cache_t *mnt_cache;
+static struct list_head *mount_hashtable __read_mostly;
+static struct kmem_cache *mnt_cache __read_mostly;
static struct rw_semaphore namespace_sem;
+/* /sys/fs */
+struct kobject *fs_kobj;
+EXPORT_SYMBOL_GPL(fs_kobj);
+
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);
- tmp = tmp + (tmp >> hash_bits);
- return tmp & hash_mask;
+ tmp = tmp + (tmp >> HASH_SHIFT);
+ return tmp & (HASH_SIZE - 1);
+}
+
+#define MNT_WRITER_UNDERFLOW_LIMIT -(1<<16)
+
+/* allocation is serialized by namespace_sem */
+static int mnt_alloc_id(struct vfsmount *mnt)
+{
+ int res;
+
+retry:
+ ida_pre_get(&mnt_id_ida, GFP_KERNEL);
+ spin_lock(&vfsmount_lock);
+ res = ida_get_new(&mnt_id_ida, &mnt->mnt_id);
+ spin_unlock(&vfsmount_lock);
+ if (res == -EAGAIN)
+ goto retry;
+
+ return res;
+}
+
+static void mnt_free_id(struct vfsmount *mnt)
+{
+ spin_lock(&vfsmount_lock);
+ ida_remove(&mnt_id_ida, mnt->mnt_id);
+ spin_unlock(&vfsmount_lock);
+}
+
+/*
+ * Allocate a new peer group ID
+ *
+ * mnt_group_ida is protected by namespace_sem
+ */
+static int mnt_alloc_group_id(struct vfsmount *mnt)
+{
+ if (!ida_pre_get(&mnt_group_ida, GFP_KERNEL))
+ return -ENOMEM;
+
+ return ida_get_new_above(&mnt_group_ida, 1, &mnt->mnt_group_id);
+}
+
+/*
+ * Release a peer group ID
+ */
+void mnt_release_group_id(struct vfsmount *mnt)
+{
+ ida_remove(&mnt_group_ida, mnt->mnt_group_id);
+ mnt->mnt_group_id = 0;
}
struct vfsmount *alloc_vfsmnt(const char *name)
{
- struct vfsmount *mnt = kmem_cache_alloc(mnt_cache, GFP_KERNEL);
+ struct vfsmount *mnt = kmem_cache_zalloc(mnt_cache, GFP_KERNEL);
if (mnt) {
- memset(mnt, 0, sizeof(struct vfsmount));
+ int err;
+
+ err = mnt_alloc_id(mnt);
+ if (err)
+ goto out_free_cache;
+
+ if (name) {
+ mnt->mnt_devname = kstrdup(name, GFP_KERNEL);
+ if (!mnt->mnt_devname)
+ goto out_free_id;
+ }
+
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);
- if (name) {
- int size = strlen(name) + 1;
- char *newname = kmalloc(size, GFP_KERNEL);
- if (newname) {
- memcpy(newname, name, size);
- mnt->mnt_devname = newname;
- }
- }
+ INIT_LIST_HEAD(&mnt->mnt_share);
+ INIT_LIST_HEAD(&mnt->mnt_slave_list);
+ INIT_LIST_HEAD(&mnt->mnt_slave);
+ atomic_set(&mnt->__mnt_writers, 0);
}
return mnt;
+
+out_free_id:
+ mnt_free_id(mnt);
+out_free_cache:
+ kmem_cache_free(mnt_cache, mnt);
+ return NULL;
+}
+
+/*
+ * Most r/o checks on a fs are for operations that take
+ * discrete amounts of time, like a write() or unlink().
+ * We must keep track of when those operations start
+ * (for permission checks) and when they end, so that
+ * we can determine when writes are able to occur to
+ * a filesystem.
+ */
+/*
+ * __mnt_is_readonly: check whether a mount is read-only
+ * @mnt: the mount to check for its write status
+ *
+ * This shouldn't be used directly ouside of the VFS.
+ * It does not guarantee that the filesystem will stay
+ * r/w, just that it is right *now*. This can not and
+ * should not be used in place of IS_RDONLY(inode).
+ * mnt_want/drop_write() will _keep_ the filesystem
+ * r/w.
+ */
+int __mnt_is_readonly(struct vfsmount *mnt)
+{
+ if (mnt->mnt_flags & MNT_READONLY)
+ return 1;
+ if (mnt->mnt_sb->s_flags & MS_RDONLY)
+ return 1;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__mnt_is_readonly);
+
+struct mnt_writer {
+ /*
+ * If holding multiple instances of this lock, they
+ * must be ordered by cpu number.
+ */
+ spinlock_t lock;
+ struct lock_class_key lock_class; /* compiles out with !lockdep */
+ unsigned long count;
+ struct vfsmount *mnt;
+} ____cacheline_aligned_in_smp;
+static DEFINE_PER_CPU(struct mnt_writer, mnt_writers);
+
+static int __init init_mnt_writers(void)
+{
+ int cpu;
+ for_each_possible_cpu(cpu) {
+ struct mnt_writer *writer = &per_cpu(mnt_writers, cpu);
+ spin_lock_init(&writer->lock);
+ lockdep_set_class(&writer->lock, &writer->lock_class);
+ writer->count = 0;
+ }
+ return 0;
+}
+fs_initcall(init_mnt_writers);
+
+static void unlock_mnt_writers(void)
+{
+ int cpu;
+ struct mnt_writer *cpu_writer;
+
+ for_each_possible_cpu(cpu) {
+ cpu_writer = &per_cpu(mnt_writers, cpu);
+ spin_unlock(&cpu_writer->lock);
+ }
+}
+
+static inline void __clear_mnt_count(struct mnt_writer *cpu_writer)
+{
+ if (!cpu_writer->mnt)
+ return;
+ /*
+ * This is in case anyone ever leaves an invalid,
+ * old ->mnt and a count of 0.
+ */
+ if (!cpu_writer->count)
+ return;
+ atomic_add(cpu_writer->count, &cpu_writer->mnt->__mnt_writers);
+ cpu_writer->count = 0;
+}
+ /*
+ * must hold cpu_writer->lock
+ */
+static inline void use_cpu_writer_for_mount(struct mnt_writer *cpu_writer,
+ struct vfsmount *mnt)
+{
+ if (cpu_writer->mnt == mnt)
+ return;
+ __clear_mnt_count(cpu_writer);
+ cpu_writer->mnt = mnt;
+}
+
+/*
+ * Most r/o checks on a fs are for operations that take
+ * discrete amounts of time, like a write() or unlink().
+ * We must keep track of when those operations start
+ * (for permission checks) and when they end, so that
+ * we can determine when writes are able to occur to
+ * a filesystem.
+ */
+/**
+ * mnt_want_write - get write access to a mount
+ * @mnt: 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 before returning success. When
+ * the write operation is finished, mnt_drop_write()
+ * must be called. This is effectively a refcount.
+ */
+int mnt_want_write(struct vfsmount *mnt)
+{
+ int ret = 0;
+ struct mnt_writer *cpu_writer;
+
+ cpu_writer = &get_cpu_var(mnt_writers);
+ spin_lock(&cpu_writer->lock);
+ if (__mnt_is_readonly(mnt)) {
+ ret = -EROFS;
+ goto out;
+ }
+ use_cpu_writer_for_mount(cpu_writer, mnt);
+ cpu_writer->count++;
+out:
+ spin_unlock(&cpu_writer->lock);
+ put_cpu_var(mnt_writers);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(mnt_want_write);
+
+static void lock_mnt_writers(void)
+{
+ int cpu;
+ struct mnt_writer *cpu_writer;
+
+ for_each_possible_cpu(cpu) {
+ cpu_writer = &per_cpu(mnt_writers, cpu);
+ spin_lock(&cpu_writer->lock);
+ __clear_mnt_count(cpu_writer);
+ cpu_writer->mnt = NULL;
+ }
+}
+
+/*
+ * These per-cpu write counts are not guaranteed to have
+ * matched increments and decrements on any given cpu.
+ * A file open()ed for write on one cpu and close()d on
+ * another cpu will imbalance this count. Make sure it
+ * does not get too far out of whack.
+ */
+static void handle_write_count_underflow(struct vfsmount *mnt)
+{
+ if (atomic_read(&mnt->__mnt_writers) >=
+ MNT_WRITER_UNDERFLOW_LIMIT)
+ return;
+ /*
+ * It isn't necessary to hold all of the locks
+ * at the same time, but doing it this way makes
+ * us share a lot more code.
+ */
+ lock_mnt_writers();
+ /*
+ * vfsmount_lock is for mnt_flags.
+ */
+ spin_lock(&vfsmount_lock);
+ /*
+ * If coalescing the per-cpu writer counts did not
+ * get us back to a positive writer count, we have
+ * a bug.
+ */
+ if ((atomic_read(&mnt->__mnt_writers) < 0) &&
+ !(mnt->mnt_flags & MNT_IMBALANCED_WRITE_COUNT)) {
+ WARN(1, KERN_DEBUG "leak detected on mount(%p) writers "
+ "count: %d\n",
+ mnt, atomic_read(&mnt->__mnt_writers));
+ /* use the flag to keep the dmesg spam down */
+ mnt->mnt_flags |= MNT_IMBALANCED_WRITE_COUNT;
+ }
+ spin_unlock(&vfsmount_lock);
+ unlock_mnt_writers();
+}
+
+/**
+ * mnt_drop_write - 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.
+ */
+void mnt_drop_write(struct vfsmount *mnt)
+{
+ int must_check_underflow = 0;
+ struct mnt_writer *cpu_writer;
+
+ cpu_writer = &get_cpu_var(mnt_writers);
+ spin_lock(&cpu_writer->lock);
+
+ use_cpu_writer_for_mount(cpu_writer, mnt);
+ if (cpu_writer->count > 0) {
+ cpu_writer->count--;
+ } else {
+ must_check_underflow = 1;
+ atomic_dec(&mnt->__mnt_writers);
+ }
+
+ spin_unlock(&cpu_writer->lock);
+ /*
+ * Logically, we could call this each time,
+ * but the __mnt_writers cacheline tends to
+ * be cold, and makes this expensive.
+ */
+ if (must_check_underflow)
+ handle_write_count_underflow(mnt);
+ /*
+ * This could be done right after the spinlock
+ * is taken because the spinlock keeps us on
+ * the cpu, and disables preemption. However,
+ * putting it here bounds the amount that
+ * __mnt_writers can underflow. Without it,
+ * we could theoretically wrap __mnt_writers.
+ */
+ put_cpu_var(mnt_writers);
+}
+EXPORT_SYMBOL_GPL(mnt_drop_write);
+
+static int mnt_make_readonly(struct vfsmount *mnt)
+{
+ int ret = 0;
+
+ lock_mnt_writers();
+ /*
+ * With all the locks held, this value is stable
+ */
+ if (atomic_read(&mnt->__mnt_writers) > 0) {
+ ret = -EBUSY;
+ goto out;
+ }
+ /*
+ * nobody can do a successful mnt_want_write() with all
+ * of the counts in MNT_DENIED_WRITE and the locks held.
+ */
+ spin_lock(&vfsmount_lock);
+ if (!ret)
+ mnt->mnt_flags |= MNT_READONLY;
+ spin_unlock(&vfsmount_lock);
+out:
+ unlock_mnt_writers();
+ return ret;
+}
+
+static void __mnt_unmake_readonly(struct vfsmount *mnt)
+{
+ spin_lock(&vfsmount_lock);
+ mnt->mnt_flags &= ~MNT_READONLY;
+ spin_unlock(&vfsmount_lock);
}
+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);
+ mnt_free_id(mnt);
kmem_cache_free(mnt_cache, 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 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;
}
+/*
+ * 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);
+ if ((child_mnt = __lookup_mnt(mnt, dentry, 1)))
+ mntget(child_mnt);
+ spin_unlock(&vfsmount_lock);
+ return child_mnt;
+}
+
static inline int check_mnt(struct vfsmount *mnt)
{
- return mnt->mnt_namespace == current->namespace;
+ return mnt->mnt_ns == current->nsproxy->mnt_ns;
}
-static void touch_namespace(struct namespace *ns)
+static void touch_mnt_namespace(struct mnt_namespace *ns)
{
if (ns) {
ns->event = ++event;
}
}
-static void __touch_namespace(struct namespace *ns)
+static void __touch_mnt_namespace(struct mnt_namespace *ns)
{
if (ns && ns->event != event) {
ns->event = event;
}
}
-static void detach_mnt(struct vfsmount *mnt, struct nameidata *old_nd)
+static void detach_mnt(struct vfsmount *mnt, struct path *old_path)
{
- old_nd->dentry = mnt->mnt_mountpoint;
- old_nd->mnt = mnt->mnt_parent;
+ old_path->dentry = mnt->mnt_mountpoint;
+ old_path->mnt = mnt->mnt_parent;
mnt->mnt_parent = mnt;
mnt->mnt_mountpoint = mnt->mnt_root;
list_del_init(&mnt->mnt_child);
list_del_init(&mnt->mnt_hash);
- old_nd->dentry->d_mounted--;
+ old_path->dentry->d_mounted--;
}
-static void attach_mnt(struct vfsmount *mnt, struct nameidata *nd)
+void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry,
+ struct vfsmount *child_mnt)
{
- mnt->mnt_parent = mntget(nd->mnt);
- mnt->mnt_mountpoint = dget(nd->dentry);
- list_add(&mnt->mnt_hash, mount_hashtable + hash(nd->mnt, nd->dentry));
- list_add_tail(&mnt->mnt_child, &nd->mnt->mnt_mounts);
- nd->dentry->d_mounted++;
+ child_mnt->mnt_parent = mntget(mnt);
+ child_mnt->mnt_mountpoint = dget(dentry);
+ dentry->d_mounted++;
+}
+
+static void attach_mnt(struct vfsmount *mnt, struct path *path)
+{
+ mnt_set_mountpoint(path->mnt, path->dentry, mnt);
+ list_add_tail(&mnt->mnt_hash, mount_hashtable +
+ hash(path->mnt, path->dentry));
+ list_add_tail(&mnt->mnt_child, &path->mnt->mnt_mounts);
+}
+
+/*
+ * 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)
return list_entry(next, struct vfsmount, mnt_child);
}
+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 vfsmount *mnt = alloc_vfsmnt(old->mnt_devname);
if (mnt) {
+ if (flag & (CL_SLAVE | CL_PRIVATE))
+ mnt->mnt_group_id = 0; /* not a peer of original */
+ else
+ mnt->mnt_group_id = old->mnt_group_id;
+
+ if ((flag & CL_MAKE_SHARED) && !mnt->mnt_group_id) {
+ int err = mnt_alloc_group_id(mnt);
+ if (err)
+ goto out_free;
+ }
+
mnt->mnt_flags = old->mnt_flags;
atomic_inc(&sb->s_active);
mnt->mnt_sb = sb;
mnt->mnt_root = dget(root);
mnt->mnt_mountpoint = mnt->mnt_root;
mnt->mnt_parent = mnt;
- mnt->mnt_namespace = current->namespace;
+
+ 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_PRIVATE)) {
+ 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;
+
+ out_free:
+ free_vfsmnt(mnt);
+ return NULL;
}
static inline void __mntput(struct vfsmount *mnt)
{
+ int cpu;
struct super_block *sb = mnt->mnt_sb;
+ /*
+ * We don't have to hold all of the locks at the
+ * same time here because we know that we're the
+ * last reference to mnt and that no new writers
+ * can come in.
+ */
+ for_each_possible_cpu(cpu) {
+ struct mnt_writer *cpu_writer = &per_cpu(mnt_writers, cpu);
+ spin_lock(&cpu_writer->lock);
+ if (cpu_writer->mnt != mnt) {
+ spin_unlock(&cpu_writer->lock);
+ continue;
+ }
+ atomic_add(cpu_writer->count, &mnt->__mnt_writers);
+ cpu_writer->count = 0;
+ /*
+ * Might as well do this so that no one
+ * ever sees the pointer and expects
+ * it to be valid.
+ */
+ cpu_writer->mnt = NULL;
+ spin_unlock(&cpu_writer->lock);
+ }
+ /*
+ * This probably indicates that somebody messed
+ * up a mnt_want/drop_write() pair. If this
+ * happens, the filesystem was probably unable
+ * to make r/w->r/o transitions.
+ */
+ WARN_ON(atomic_read(&mnt->__mnt_writers));
dput(mnt->mnt_root);
free_vfsmnt(mnt);
deactivate_super(sb);
EXPORT_SYMBOL(mnt_unpin);
+static inline void mangle(struct seq_file *m, const char *s)
+{
+ seq_escape(m, s, " \t\n\\");
+}
+
+/*
+ * Simple .show_options callback for filesystems which don't want to
+ * implement more complex mount option showing.
+ *
+ * See also save_mount_options().
+ */
+int generic_show_options(struct seq_file *m, struct vfsmount *mnt)
+{
+ const char *options = mnt->mnt_sb->s_options;
+
+ if (options != NULL && options[0]) {
+ seq_putc(m, ',');
+ mangle(m, options);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(generic_show_options);
+
+/*
+ * If filesystem uses generic_show_options(), this function should be
+ * called from the fill_super() callback.
+ *
+ * The .remount_fs callback usually needs to be handled in a special
+ * way, to make sure, that previous options are not overwritten if the
+ * remount fails.
+ *
+ * Also note, that if the filesystem's .remount_fs function doesn't
+ * reset all options to their default value, but changes only newly
+ * given options, then the displayed options will not reflect reality
+ * any more.
+ */
+void save_mount_options(struct super_block *sb, char *options)
+{
+ kfree(sb->s_options);
+ sb->s_options = kstrdup(options, GFP_KERNEL);
+}
+EXPORT_SYMBOL(save_mount_options);
+
+#ifdef CONFIG_PROC_FS
/* iterator */
static void *m_start(struct seq_file *m, loff_t *pos)
{
- struct namespace *n = m->private;
- struct list_head *p;
- loff_t l = *pos;
+ struct proc_mounts *p = m->private;
down_read(&namespace_sem);
- list_for_each(p, &n->list)
- if (!l--)
- return list_entry(p, struct vfsmount, mnt_list);
- return NULL;
+ return seq_list_start(&p->ns->list, *pos);
}
static void *m_next(struct seq_file *m, void *v, loff_t *pos)
{
- struct 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);
+ struct proc_mounts *p = m->private;
+
+ return seq_list_next(v, &p->ns->list, pos);
}
static void m_stop(struct seq_file *m, void *v)
up_read(&namespace_sem);
}
-static inline void mangle(struct seq_file *m, const char *s)
-{
- seq_escape(m, s, " \t\n\\");
-}
+struct proc_fs_info {
+ int flag;
+ const char *str;
+};
-static int show_vfsmnt(struct seq_file *m, void *v)
+static int show_sb_opts(struct seq_file *m, struct super_block *sb)
{
- struct vfsmount *mnt = v;
- int err = 0;
- static struct proc_fs_info {
- int flag;
- char *str;
- } fs_info[] = {
+ static const struct proc_fs_info fs_info[] = {
{ MS_SYNCHRONOUS, ",sync" },
{ MS_DIRSYNC, ",dirsync" },
{ MS_MANDLOCK, ",mand" },
- { MS_NOATIME, ",noatime" },
- { MS_NODIRATIME, ",nodiratime" },
{ 0, NULL }
};
- static struct proc_fs_info mnt_info[] = {
+ const struct proc_fs_info *fs_infop;
+
+ for (fs_infop = fs_info; fs_infop->flag; fs_infop++) {
+ if (sb->s_flags & fs_infop->flag)
+ seq_puts(m, fs_infop->str);
+ }
+
+ return security_sb_show_options(m, sb);
+}
+
+static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt)
+{
+ static const struct proc_fs_info mnt_info[] = {
{ MNT_NOSUID, ",nosuid" },
{ MNT_NODEV, ",nodev" },
{ MNT_NOEXEC, ",noexec" },
+ { MNT_NOATIME, ",noatime" },
+ { MNT_NODIRATIME, ",nodiratime" },
+ { MNT_RELATIME, ",relatime" },
{ 0, NULL }
};
- struct proc_fs_info *fs_infop;
+ const struct proc_fs_info *fs_infop;
+
+ for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) {
+ if (mnt->mnt_flags & fs_infop->flag)
+ seq_puts(m, fs_infop->str);
+ }
+}
+
+static void show_type(struct seq_file *m, struct super_block *sb)
+{
+ mangle(m, sb->s_type->name);
+ if (sb->s_subtype && sb->s_subtype[0]) {
+ seq_putc(m, '.');
+ mangle(m, sb->s_subtype);
+ }
+}
+
+static int show_vfsmnt(struct seq_file *m, void *v)
+{
+ struct vfsmount *mnt = list_entry(v, struct vfsmount, mnt_list);
+ int err = 0;
+ struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
seq_putc(m, ' ');
- seq_path(m, mnt, mnt->mnt_root, " \t\n\\");
+ seq_path(m, &mnt_path, " \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);
+ show_type(m, mnt->mnt_sb);
+ seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
+ err = show_sb_opts(m, mnt->mnt_sb);
+ if (err)
+ goto out;
+ show_mnt_opts(m, mnt);
+ if (mnt->mnt_sb->s_op->show_options)
+ err = mnt->mnt_sb->s_op->show_options(m, mnt);
+ seq_puts(m, " 0 0\n");
+out:
+ return err;
+}
+
+const struct seq_operations mounts_op = {
+ .start = m_start,
+ .next = m_next,
+ .stop = m_stop,
+ .show = show_vfsmnt
+};
+
+static int show_mountinfo(struct seq_file *m, void *v)
+{
+ struct proc_mounts *p = m->private;
+ struct vfsmount *mnt = list_entry(v, struct vfsmount, mnt_list);
+ struct super_block *sb = mnt->mnt_sb;
+ struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
+ struct path root = p->root;
+ int err = 0;
+
+ 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\\");
+ seq_putc(m, ' ');
+ seq_path_root(m, &mnt_path, &root, " \t\n\\");
+ if (root.mnt != p->root.mnt || root.dentry != p->root.dentry) {
+ /*
+ * Mountpoint is outside root, discard that one. Ugly,
+ * but less so than trying to do that in iterator in a
+ * race-free way (due to renames).
+ */
+ return SEQ_SKIP;
}
- for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) {
- if (mnt->mnt_flags & fs_infop->flag)
- seq_puts(m, fs_infop->str);
+ seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw");
+ show_mnt_opts(m, mnt);
+
+ /* Tagged fields ("foo:X" or "bar") */
+ if (IS_MNT_SHARED(mnt))
+ seq_printf(m, " shared:%i", mnt->mnt_group_id);
+ if (IS_MNT_SLAVE(mnt)) {
+ int master = mnt->mnt_master->mnt_group_id;
+ int dom = get_dominating_id(mnt, &p->root);
+ seq_printf(m, " master:%i", master);
+ if (dom && dom != master)
+ seq_printf(m, " propagate_from:%i", dom);
+ }
+ if (IS_MNT_UNBINDABLE(mnt))
+ seq_puts(m, " unbindable");
+
+ /* Filesystem specific data */
+ seq_puts(m, " - ");
+ show_type(m, sb);
+ seq_putc(m, ' ');
+ mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
+ seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw");
+ err = show_sb_opts(m, sb);
+ if (err)
+ goto out;
+ if (sb->s_op->show_options)
+ err = sb->s_op->show_options(m, mnt);
+ seq_putc(m, '\n');
+out:
+ return err;
+}
+
+const struct seq_operations mountinfo_op = {
+ .start = m_start,
+ .next = m_next,
+ .stop = m_stop,
+ .show = show_mountinfo,
+};
+
+static int show_vfsstat(struct seq_file *m, void *v)
+{
+ struct vfsmount *mnt = list_entry(v, struct vfsmount, mnt_list);
+ struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
+ int err = 0;
+
+ /* 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_path, " \t\n\\");
+ seq_putc(m, ' ');
+
+ /* file system type */
+ seq_puts(m, "with fstype ");
+ show_type(m, mnt->mnt_sb);
+
+ /* optional statistics */
+ if (mnt->mnt_sb->s_op->show_stats) {
+ seq_putc(m, ' ');
+ err = mnt->mnt_sb->s_op->show_stats(m, mnt);
}
- if (mnt->mnt_sb->s_op->show_options)
- err = mnt->mnt_sb->s_op->show_options(m, mnt);
- seq_puts(m, " 0 0\n");
+
+ seq_putc(m, '\n');
return err;
}
-struct seq_operations mounts_op = {
+const struct seq_operations mountstats_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
- .show = show_vfsmnt
+ .show = show_vfsstat,
};
+#endif /* CONFIG_PROC_FS */
/**
* may_umount_tree - check if a mount tree is busy
spin_unlock(&vfsmount_lock);
if (actual_refs > minimum_refs)
- return -EBUSY;
+ return 0;
- return 0;
+ return 1;
}
EXPORT_SYMBOL(may_umount_tree);
*/
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 void release_mounts(struct list_head *head)
+void release_mounts(struct list_head *head)
{
struct vfsmount *mnt;
- while(!list_empty(head)) {
- mnt = list_entry(head->next, struct vfsmount, mnt_hash);
+ while (!list_empty(head)) {
+ mnt = list_first_entry(head, struct vfsmount, mnt_hash);
list_del_init(&mnt->mnt_hash);
if (mnt->mnt_parent != mnt) {
struct dentry *dentry;
m = mnt->mnt_parent;
mnt->mnt_mountpoint = mnt->mnt_root;
mnt->mnt_parent = mnt;
+ m->mnt_ghosts--;
spin_unlock(&vfsmount_lock);
dput(dentry);
mntput(m);
}
}
-static void umount_tree(struct vfsmount *mnt, struct list_head *kill)
+void umount_tree(struct vfsmount *mnt, int propagate, struct list_head *kill)
{
struct vfsmount *p;
- for (p = mnt; p; p = next_mnt(p, mnt)) {
- list_del(&p->mnt_hash);
- list_add(&p->mnt_hash, 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_namespace(p->mnt_namespace);
- p->mnt_namespace = NULL;
+ __touch_mnt_namespace(p->mnt_ns);
+ p->mnt_ns = NULL;
list_del_init(&p->mnt_child);
- if (p->mnt_parent != p)
- mnt->mnt_mountpoint->d_mounted--;
+ if (p->mnt_parent != p) {
+ p->mnt_parent->mnt_ghosts++;
+ p->mnt_mountpoint->d_mounted--;
+ }
+ change_mnt_propagation(p, MS_PRIVATE);
}
}
+static void shrink_submounts(struct vfsmount *mnt, struct list_head *umounts);
+
static int do_umount(struct vfsmount *mnt, int flags)
{
struct super_block *sb = mnt->mnt_sb;
* (2) the usage count == 1 [parent vfsmount] + 1 [sys_umount]
*/
if (flags & MNT_EXPIRE) {
- if (mnt == current->fs->rootmnt ||
+ if (mnt == current->fs->root.mnt ||
flags & (MNT_FORCE | MNT_DETACH))
return -EINVAL;
* about for the moment.
*/
- lock_kernel();
- if ((flags & MNT_FORCE) && sb->s_op->umount_begin)
+ if (flags & MNT_FORCE && sb->s_op->umount_begin) {
+ lock_kernel();
sb->s_op->umount_begin(sb);
- unlock_kernel();
+ unlock_kernel();
+ }
/*
* No sense to grab the lock for this test, but test itself looks
* /reboot - static binary that would close all descriptors and
* call reboot(9). Then init(8) could umount root and exec /reboot.
*/
- if (mnt == current->fs->rootmnt && !(flags & MNT_DETACH)) {
+ if (mnt == current->fs->root.mnt && !(flags & MNT_DETACH)) {
/*
* Special case for "unmounting" root ...
* we just try to remount it readonly.
down_write(&sb->s_umount);
if (!(sb->s_flags & MS_RDONLY)) {
lock_kernel();
- DQUOT_OFF(sb);
retval = do_remount_sb(sb, MS_RDONLY, NULL, 0);
unlock_kernel();
}
spin_lock(&vfsmount_lock);
event++;
+ if (!(flags & MNT_DETACH))
+ shrink_submounts(mnt, &umount_list);
+
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_list);
+ umount_tree(mnt, 1, &umount_list);
retval = 0;
}
spin_unlock(&vfsmount_lock);
* unixes. Our API is identical to OSF/1 to avoid making a mess of AMD
*/
-asmlinkage long sys_umount(char __user * name, int flags)
+SYSCALL_DEFINE2(umount, char __user *, name, int, flags)
{
- struct nameidata nd;
+ struct path path;
int retval;
- retval = __user_walk(name, LOOKUP_FOLLOW, &nd);
+ retval = user_path(name, &path);
if (retval)
goto out;
retval = -EINVAL;
- if (nd.dentry != nd.mnt->mnt_root)
+ if (path.dentry != path.mnt->mnt_root)
goto dput_and_out;
- if (!check_mnt(nd.mnt))
+ if (!check_mnt(path.mnt))
goto dput_and_out;
retval = -EPERM;
if (!capable(CAP_SYS_ADMIN))
goto dput_and_out;
- retval = do_umount(nd.mnt, flags);
+ retval = do_umount(path.mnt, flags);
dput_and_out:
- path_release_on_umount(&nd);
+ /* we mustn't call path_put() as that would clear mnt_expiry_mark */
+ dput(path.dentry);
+ mntput_no_expire(path.mnt);
out:
return retval;
}
/*
* The 2.0 compatible umount. No flags.
*/
-asmlinkage long sys_oldumount(char __user * name)
+SYSCALL_DEFINE1(oldumount, char __user *, name)
{
return sys_umount(name, 0);
}
#endif
-static int mount_is_safe(struct nameidata *nd)
+static int mount_is_safe(struct path *path)
{
if (capable(CAP_SYS_ADMIN))
return 0;
return -EPERM;
#ifdef notyet
- if (S_ISLNK(nd->dentry->d_inode->i_mode))
+ if (S_ISLNK(path->dentry->d_inode->i_mode))
return -EPERM;
- if (nd->dentry->d_inode->i_mode & S_ISVTX) {
- if (current->uid != nd->dentry->d_inode->i_uid)
+ if (path->dentry->d_inode->i_mode & S_ISVTX) {
+ if (current_uid() != path->dentry->d_inode->i_uid)
return -EPERM;
}
- if (permission(nd->dentry->d_inode, MAY_WRITE, nd))
+ if (inode_permission(path->dentry->d_inode, MAY_WRITE))
return -EPERM;
return 0;
#endif
}
-static int lives_below_in_same_fs(struct dentry *d, struct dentry *dentry)
-{
- while (1) {
- if (d == dentry)
- return 1;
- if (d == NULL || d == d->d_parent)
- return 0;
- d = d->d_parent;
- }
-}
-
-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 nameidata nd;
+ struct path path;
+
+ if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(mnt))
+ return NULL;
res = q = clone_mnt(mnt, dentry, flag);
if (!q)
p = mnt;
list_for_each_entry(r, &mnt->mnt_mounts, mnt_child) {
- if (!lives_below_in_same_fs(r->mnt_mountpoint, dentry))
+ if (!is_subdir(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;
}
p = s;
- nd.mnt = q;
- nd.dentry = p->mnt_mountpoint;
+ path.mnt = q;
+ path.dentry = p->mnt_mountpoint;
q = clone_mnt(p, p->mnt_root, flag);
if (!q)
goto Enomem;
spin_lock(&vfsmount_lock);
list_add_tail(&q->mnt_list, &res->mnt_list);
- attach_mnt(q, &nd);
+ attach_mnt(q, &path);
spin_unlock(&vfsmount_lock);
}
}
if (res) {
LIST_HEAD(umount_list);
spin_lock(&vfsmount_lock);
- umount_tree(res, &umount_list);
+ umount_tree(res, 0, &umount_list);
spin_unlock(&vfsmount_lock);
release_mounts(&umount_list);
}
return NULL;
}
-static int graft_tree(struct vfsmount *mnt, struct nameidata *nd)
+struct vfsmount *collect_mounts(struct vfsmount *mnt, struct dentry *dentry)
+{
+ struct vfsmount *tree;
+ down_write(&namespace_sem);
+ tree = copy_tree(mnt, dentry, CL_COPY_ALL | CL_PRIVATE);
+ up_write(&namespace_sem);
+ return tree;
+}
+
+void drop_collected_mounts(struct vfsmount *mnt)
+{
+ LIST_HEAD(umount_list);
+ down_write(&namespace_sem);
+ spin_lock(&vfsmount_lock);
+ umount_tree(mnt, 0, &umount_list);
+ spin_unlock(&vfsmount_lock);
+ up_write(&namespace_sem);
+ release_mounts(&umount_list);
+}
+
+static void cleanup_group_ids(struct vfsmount *mnt, struct vfsmount *end)
+{
+ struct vfsmount *p;
+
+ for (p = mnt; p != end; p = next_mnt(p, mnt)) {
+ if (p->mnt_group_id && !IS_MNT_SHARED(p))
+ mnt_release_group_id(p);
+ }
+}
+
+static int invent_group_ids(struct vfsmount *mnt, bool recurse)
+{
+ struct vfsmount *p;
+
+ for (p = mnt; p; p = recurse ? next_mnt(p, mnt) : NULL) {
+ if (!p->mnt_group_id && !IS_MNT_SHARED(p)) {
+ int err = mnt_alloc_group_id(p);
+ if (err) {
+ cleanup_group_ids(mnt, p);
+ return err;
+ }
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * @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 path *path, struct path *parent_path)
+{
+ LIST_HEAD(tree_list);
+ struct vfsmount *dest_mnt = path->mnt;
+ struct dentry *dest_dentry = path->dentry;
+ struct vfsmount *child, *p;
+ int err;
+
+ if (IS_MNT_SHARED(dest_mnt)) {
+ err = invent_group_ids(source_mnt, true);
+ if (err)
+ goto out;
+ }
+ err = propagate_mnt(dest_mnt, dest_dentry, source_mnt, &tree_list);
+ if (err)
+ goto out_cleanup_ids;
+
+ 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_path) {
+ detach_mnt(source_mnt, parent_path);
+ attach_mnt(source_mnt, path);
+ 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;
+
+ out_cleanup_ids:
+ if (IS_MNT_SHARED(dest_mnt))
+ cleanup_group_ids(source_mnt, NULL);
+ out:
+ return err;
+}
+
+static int graft_tree(struct vfsmount *mnt, struct path *path)
{
int err;
if (mnt->mnt_sb->s_flags & MS_NOUSER)
return -EINVAL;
- if (S_ISDIR(nd->dentry->d_inode->i_mode) !=
+ if (S_ISDIR(path->dentry->d_inode->i_mode) !=
S_ISDIR(mnt->mnt_root->d_inode->i_mode))
return -ENOTDIR;
err = -ENOENT;
- down(&nd->dentry->d_inode->i_sem);
- if (IS_DEADDIR(nd->dentry->d_inode))
+ mutex_lock(&path->dentry->d_inode->i_mutex);
+ if (IS_DEADDIR(path->dentry->d_inode))
goto out_unlock;
- err = security_sb_check_sb(mnt, nd);
+ err = security_sb_check_sb(mnt, path);
if (err)
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);
- err = 0;
- touch_namespace(current->namespace);
- }
- spin_unlock(&vfsmount_lock);
+ if (IS_ROOT(path->dentry) || !d_unhashed(path->dentry))
+ err = attach_recursive_mnt(mnt, path, NULL);
out_unlock:
- up(&nd->dentry->d_inode->i_sem);
+ mutex_unlock(&path->dentry->d_inode->i_mutex);
if (!err)
- security_sb_post_addmount(mnt, nd);
+ security_sb_post_addmount(mnt, path);
return err;
}
/*
* recursively change the type of the mountpoint.
*/
-static int do_change_type(struct nameidata *nd, int flag)
+static int do_change_type(struct path *path, int flag)
{
- struct vfsmount *m, *mnt = nd->mnt;
+ struct vfsmount *m, *mnt = path->mnt;
int recurse = flag & MS_REC;
int type = flag & ~MS_REC;
+ int err = 0;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
- if (nd->dentry != nd->mnt->mnt_root)
+ if (path->dentry != path->mnt->mnt_root)
return -EINVAL;
down_write(&namespace_sem);
+ if (type == MS_SHARED) {
+ err = invent_group_ids(mnt, recurse);
+ if (err)
+ goto out_unlock;
+ }
+
spin_lock(&vfsmount_lock);
for (m = mnt; m; m = (recurse ? next_mnt(m, mnt) : NULL))
change_mnt_propagation(m, type);
spin_unlock(&vfsmount_lock);
+
+ out_unlock:
up_write(&namespace_sem);
- return 0;
+ return err;
}
/*
* do loopback mount.
*/
-static int do_loopback(struct nameidata *nd, char *old_name, int recurse)
+static int do_loopback(struct path *path, char *old_name,
+ int recurse)
{
- struct nameidata old_nd;
+ struct path old_path;
struct vfsmount *mnt = NULL;
- int err = mount_is_safe(nd);
+ int err = mount_is_safe(path);
if (err)
return err;
if (!old_name || !*old_name)
return -EINVAL;
- err = path_lookup(old_name, LOOKUP_FOLLOW, &old_nd);
+ err = kern_path(old_name, LOOKUP_FOLLOW, &old_path);
if (err)
return err;
down_write(&namespace_sem);
err = -EINVAL;
- if (!check_mnt(nd->mnt) || !check_mnt(old_nd.mnt))
+ if (IS_MNT_UNBINDABLE(old_path.mnt))
+ goto out;
+
+ if (!check_mnt(path->mnt) || !check_mnt(old_path.mnt))
goto out;
err = -ENOMEM;
if (recurse)
- mnt = copy_tree(old_nd.mnt, old_nd.dentry, 0);
+ mnt = copy_tree(old_path.mnt, old_path.dentry, 0);
else
- mnt = clone_mnt(old_nd.mnt, old_nd.dentry, 0);
+ mnt = clone_mnt(old_path.mnt, old_path.dentry, 0);
if (!mnt)
goto out;
- err = graft_tree(mnt, nd);
+ err = graft_tree(mnt, path);
if (err) {
LIST_HEAD(umount_list);
spin_lock(&vfsmount_lock);
- umount_tree(mnt, &umount_list);
+ umount_tree(mnt, 0, &umount_list);
spin_unlock(&vfsmount_lock);
release_mounts(&umount_list);
}
out:
up_write(&namespace_sem);
- path_release(&old_nd);
+ path_put(&old_path);
return err;
}
+static int change_mount_flags(struct vfsmount *mnt, int ms_flags)
+{
+ int error = 0;
+ int readonly_request = 0;
+
+ if (ms_flags & MS_RDONLY)
+ readonly_request = 1;
+ if (readonly_request == __mnt_is_readonly(mnt))
+ return 0;
+
+ if (readonly_request)
+ error = mnt_make_readonly(mnt);
+ else
+ __mnt_unmake_readonly(mnt);
+ return error;
+}
+
/*
* change filesystem flags. dir should be a physical root of filesystem.
* 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,
+static int do_remount(struct path *path, int flags, int mnt_flags,
void *data)
{
int err;
- struct super_block *sb = nd->mnt->mnt_sb;
+ struct super_block *sb = path->mnt->mnt_sb;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- if (!check_mnt(nd->mnt))
+ if (!check_mnt(path->mnt))
return -EINVAL;
- if (nd->dentry != nd->mnt->mnt_root)
+ if (path->dentry != path->mnt->mnt_root)
return -EINVAL;
down_write(&sb->s_umount);
- err = do_remount_sb(sb, flags, data, 0);
+ if (flags & MS_BIND)
+ err = change_mount_flags(path->mnt, flags);
+ else
+ err = do_remount_sb(sb, flags, data, 0);
if (!err)
- nd->mnt->mnt_flags = mnt_flags;
+ path->mnt->mnt_flags = mnt_flags;
up_write(&sb->s_umount);
- if (!err)
- security_sb_post_remount(nd->mnt, flags, data);
+ if (!err) {
+ security_sb_post_remount(path->mnt, flags, data);
+
+ spin_lock(&vfsmount_lock);
+ touch_mnt_namespace(path->mnt->mnt_ns);
+ spin_unlock(&vfsmount_lock);
+ }
return err;
}
-static int do_move_mount(struct nameidata *nd, char *old_name)
+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 path *path, char *old_name)
{
- struct nameidata old_nd, parent_nd;
+ struct path old_path, parent_path;
struct vfsmount *p;
int err = 0;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (!old_name || !*old_name)
return -EINVAL;
- err = path_lookup(old_name, LOOKUP_FOLLOW, &old_nd);
+ err = kern_path(old_name, LOOKUP_FOLLOW, &old_path);
if (err)
return err;
down_write(&namespace_sem);
- while (d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
+ while (d_mountpoint(path->dentry) &&
+ follow_down(&path->mnt, &path->dentry))
;
err = -EINVAL;
- if (!check_mnt(nd->mnt) || !check_mnt(old_nd.mnt))
+ if (!check_mnt(path->mnt) || !check_mnt(old_path.mnt))
goto out;
err = -ENOENT;
- down(&nd->dentry->d_inode->i_sem);
- if (IS_DEADDIR(nd->dentry->d_inode))
+ mutex_lock(&path->dentry->d_inode->i_mutex);
+ if (IS_DEADDIR(path->dentry->d_inode))
goto out1;
- spin_lock(&vfsmount_lock);
- if (!IS_ROOT(nd->dentry) && d_unhashed(nd->dentry))
- goto out2;
+ if (!IS_ROOT(path->dentry) && d_unhashed(path->dentry))
+ goto out1;
err = -EINVAL;
- if (old_nd.dentry != old_nd.mnt->mnt_root)
- goto out2;
-
- if (old_nd.mnt == old_nd.mnt->mnt_parent)
- goto out2;
+ if (old_path.dentry != old_path.mnt->mnt_root)
+ goto out1;
- if (S_ISDIR(nd->dentry->d_inode->i_mode) !=
- S_ISDIR(old_nd.dentry->d_inode->i_mode))
- goto out2;
+ if (old_path.mnt == old_path.mnt->mnt_parent)
+ goto out1;
+ if (S_ISDIR(path->dentry->d_inode->i_mode) !=
+ S_ISDIR(old_path.dentry->d_inode->i_mode))
+ goto out1;
+ /*
+ * Don't move a mount residing in a shared parent.
+ */
+ if (old_path.mnt->mnt_parent &&
+ IS_MNT_SHARED(old_path.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(path->mnt) &&
+ tree_contains_unbindable(old_path.mnt))
+ goto out1;
err = -ELOOP;
- for (p = nd->mnt; p->mnt_parent != p; p = p->mnt_parent)
- if (p == old_nd.mnt)
- goto out2;
- err = 0;
+ for (p = path->mnt; p->mnt_parent != p; p = p->mnt_parent)
+ if (p == old_path.mnt)
+ goto out1;
- detach_mnt(old_nd.mnt, &parent_nd);
- attach_mnt(old_nd.mnt, nd);
- touch_namespace(current->namespace);
+ err = attach_recursive_mnt(old_path.mnt, path, &parent_path);
+ if (err)
+ goto out1;
/* if the mount is moved, it should no longer be expire
* automatically */
- list_del_init(&old_nd.mnt->mnt_expire);
-out2:
- spin_unlock(&vfsmount_lock);
+ list_del_init(&old_path.mnt->mnt_expire);
out1:
- up(&nd->dentry->d_inode->i_sem);
+ mutex_unlock(&path->dentry->d_inode->i_mutex);
out:
up_write(&namespace_sem);
if (!err)
- path_release(&parent_nd);
- path_release(&old_nd);
+ path_put(&parent_path);
+ path_put(&old_path);
return err;
}
* 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,
+static int do_new_mount(struct path *path, char *type, int flags,
int mnt_flags, char *name, void *data)
{
struct vfsmount *mnt;
if (IS_ERR(mnt))
return PTR_ERR(mnt);
- return do_add_mount(mnt, nd, mnt_flags, NULL);
+ return do_add_mount(mnt, path, 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 do_add_mount(struct vfsmount *newmnt, struct path *path,
int mnt_flags, struct list_head *fslist)
{
int err;
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(path->dentry) &&
+ follow_down(&path->mnt, &path->dentry))
;
err = -EINVAL;
- if (!check_mnt(nd->mnt))
+ if (!check_mnt(path->mnt))
goto unlock;
/* Refuse the same filesystem on the same mount point */
err = -EBUSY;
- if (nd->mnt->mnt_sb == newmnt->mnt_sb &&
- nd->mnt->mnt_root == nd->dentry)
+ if (path->mnt->mnt_sb == newmnt->mnt_sb &&
+ path->mnt->mnt_root == path->dentry)
goto unlock;
err = -EINVAL;
goto unlock;
newmnt->mnt_flags = mnt_flags;
- if ((err = graft_tree(newmnt, nd)))
+ if ((err = graft_tree(newmnt, path)))
goto unlock;
- if (fslist) {
- /* add to the specified expiration list */
- spin_lock(&vfsmount_lock);
+ if (fslist) /* add to the specified expiration list */
list_add_tail(&newmnt->mnt_expire, fslist);
- spin_unlock(&vfsmount_lock);
- }
+
up_write(&namespace_sem);
return 0;
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 (atomic_read(&mnt->mnt_count) == 2) {
- /* delete from the namespace */
- touch_namespace(mnt->mnt_namespace);
- list_del_init(&mnt->mnt_list);
- mnt->mnt_namespace = NULL;
- umount_tree(mnt, 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);
- }
-}
-
/*
* 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
*/
void mark_mounts_for_expiry(struct list_head *mounts)
{
- struct namespace *namespace;
struct vfsmount *mnt, *next;
LIST_HEAD(graveyard);
+ LIST_HEAD(umounts);
if (list_empty(mounts))
return;
+ down_write(&namespace_sem);
spin_lock(&vfsmount_lock);
/* extract from the expiration list every vfsmount that matches the
*/
list_for_each_entry_safe(mnt, next, mounts, mnt_expire) {
if (!xchg(&mnt->mnt_expiry_mark, 1) ||
- atomic_read(&mnt->mnt_count) != 1)
+ propagate_mount_busy(mnt, 1))
continue;
-
- mntget(mnt);
list_move(&mnt->mnt_expire, &graveyard);
}
-
- /*
- * 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
- */
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 */
- namespace = mnt->mnt_namespace;
- if (!namespace || !namespace->root)
- continue;
- get_namespace(namespace);
-
- spin_unlock(&vfsmount_lock);
- down_write(&namespace_sem);
- expire_mount(mnt, mounts, &umounts);
- up_write(&namespace_sem);
- release_mounts(&umounts);
- mntput(mnt);
- put_namespace(namespace);
- spin_lock(&vfsmount_lock);
+ mnt = list_first_entry(&graveyard, struct vfsmount, mnt_expire);
+ touch_mnt_namespace(mnt->mnt_ns);
+ umount_tree(mnt, 1, &umounts);
}
-
spin_unlock(&vfsmount_lock);
+ up_write(&namespace_sem);
+
+ release_mounts(&umounts);
}
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)) {
+ 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
+ */
+static void shrink_submounts(struct vfsmount *mnt, struct list_head *umounts)
+{
+ LIST_HEAD(graveyard);
+ struct vfsmount *m;
+
+ /* extract submounts of 'mountpoint' from the expiration list */
+ while (select_submounts(mnt, &graveyard)) {
+ while (!list_empty(&graveyard)) {
+ m = list_first_entry(&graveyard, struct vfsmount,
+ mnt_expire);
+ touch_mnt_namespace(m->mnt_ns);
+ umount_tree(m, 1, umounts);
+ }
+ }
+}
+
+/*
* 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
long do_mount(char *dev_name, char *dir_name, char *type_page,
unsigned long flags, void *data_page)
{
- struct nameidata nd;
+ struct path path;
int retval = 0;
int mnt_flags = 0;
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 (flags & MS_RDONLY)
+ mnt_flags |= MNT_READONLY;
+
+ flags &= ~(MS_NOSUID | MS_NOEXEC | MS_NODEV | MS_ACTIVE |
+ MS_NOATIME | MS_NODIRATIME | MS_RELATIME| MS_KERNMOUNT);
/* ... and get the mountpoint */
- retval = path_lookup(dir_name, LOOKUP_FOLLOW, &nd);
+ retval = kern_path(dir_name, LOOKUP_FOLLOW, &path);
if (retval)
return retval;
- retval = security_sb_mount(dev_name, &nd, type_page, flags, data_page);
+ retval = security_sb_mount(dev_name, &path,
+ type_page, flags, data_page);
if (retval)
goto dput_out;
if (flags & MS_REMOUNT)
- retval = do_remount(&nd, flags & ~MS_REMOUNT, mnt_flags,
+ retval = do_remount(&path, flags & ~MS_REMOUNT, mnt_flags,
data_page);
else if (flags & MS_BIND)
- retval = do_loopback(&nd, dev_name, flags & MS_REC);
- else if (flags & MS_PRIVATE)
- retval = do_change_type(&nd, flags);
+ retval = do_loopback(&path, dev_name, flags & MS_REC);
+ else if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
+ retval = do_change_type(&path, flags);
else if (flags & MS_MOVE)
- retval = do_move_mount(&nd, dev_name);
+ retval = do_move_mount(&path, dev_name);
else
- retval = do_new_mount(&nd, type_page, flags, mnt_flags,
+ retval = do_new_mount(&path, type_page, flags, mnt_flags,
dev_name, data_page);
dput_out:
- path_release(&nd);
+ path_put(&path);
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.
+ */
+static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns,
+ struct fs_struct *fs)
{
- struct namespace *namespace = tsk->namespace;
- struct namespace *new_ns;
- struct vfsmount *rootmnt = NULL, *pwdmnt = NULL, *altrootmnt = NULL;
- struct fs_struct *fs = tsk->fs;
+ struct mnt_namespace *new_ns;
+ struct vfsmount *rootmnt = NULL, *pwdmnt = NULL;
struct vfsmount *p, *q;
- if (!namespace)
- return 0;
-
- 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 ERR_PTR(-ENOMEM);
atomic_set(&new_ns->count, 1);
INIT_LIST_HEAD(&new_ns->list);
down_write(&namespace_sem);
/* First pass: copy the tree topology */
- new_ns->root = copy_tree(namespace->root, namespace->root->mnt_root,
- CL_EXPIRE);
+ new_ns->root = copy_tree(mnt_ns->root, mnt_ns->root->mnt_root,
+ CL_COPY_ALL | CL_EXPIRE);
if (!new_ns->root) {
up_write(&namespace_sem);
kfree(new_ns);
- goto out;
+ return ERR_PTR(-ENOMEM);
}
spin_lock(&vfsmount_lock);
list_add_tail(&new_ns->list, &new_ns->root->mnt_list);
* as belonging to new namespace. We have already acquired a private
* fs_struct, so tsk->fs->lock is not needed.
*/
- p = namespace->root;
+ p = mnt_ns->root;
q = new_ns->root;
while (p) {
- q->mnt_namespace = new_ns;
+ q->mnt_ns = new_ns;
if (fs) {
- if (p == fs->rootmnt) {
+ if (p == fs->root.mnt) {
rootmnt = p;
- fs->rootmnt = mntget(q);
+ fs->root.mnt = mntget(q);
}
- if (p == fs->pwdmnt) {
+ if (p == fs->pwd.mnt) {
pwdmnt = p;
- fs->pwdmnt = mntget(q);
- }
- if (p == fs->altrootmnt) {
- altrootmnt = p;
- fs->altrootmnt = mntget(q);
+ fs->pwd.mnt = mntget(q);
}
}
- p = next_mnt(p, namespace->root);
+ p = next_mnt(p, mnt_ns->root);
q = next_mnt(q, new_ns->root);
}
up_write(&namespace_sem);
- tsk->namespace = new_ns;
-
if (rootmnt)
mntput(rootmnt);
if (pwdmnt)
mntput(pwdmnt);
- if (altrootmnt)
- mntput(altrootmnt);
- put_namespace(namespace);
- return 0;
+ return new_ns;
+}
-out:
- put_namespace(namespace);
- return -ENOMEM;
+struct mnt_namespace *copy_mnt_ns(unsigned long flags, struct mnt_namespace *ns,
+ struct fs_struct *new_fs)
+{
+ struct mnt_namespace *new_ns;
+
+ BUG_ON(!ns);
+ get_mnt_ns(ns);
+
+ if (!(flags & CLONE_NEWNS))
+ return ns;
+
+ new_ns = dup_mnt_ns(ns, new_fs);
+
+ put_mnt_ns(ns);
+ return new_ns;
}
-asmlinkage long sys_mount(char __user * dev_name, char __user * dir_name,
- char __user * type, unsigned long flags,
- void __user * data)
+SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name,
+ char __user *, type, unsigned long, flags, void __user *, data)
{
int retval;
unsigned long data_page;
* Replace the fs->{rootmnt,root} with {mnt,dentry}. Put the old values.
* It can block. Requires the big lock held.
*/
-void set_fs_root(struct fs_struct *fs, struct vfsmount *mnt,
- struct dentry *dentry)
+void set_fs_root(struct fs_struct *fs, struct path *path)
{
- struct dentry *old_root;
- struct vfsmount *old_rootmnt;
+ struct path old_root;
+
write_lock(&fs->lock);
old_root = fs->root;
- old_rootmnt = fs->rootmnt;
- fs->rootmnt = mntget(mnt);
- fs->root = dget(dentry);
+ fs->root = *path;
+ path_get(path);
write_unlock(&fs->lock);
- if (old_root) {
- dput(old_root);
- mntput(old_rootmnt);
- }
+ if (old_root.dentry)
+ path_put(&old_root);
}
/*
* Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values.
* It can block. Requires the big lock held.
*/
-void set_fs_pwd(struct fs_struct *fs, struct vfsmount *mnt,
- struct dentry *dentry)
+void set_fs_pwd(struct fs_struct *fs, struct path *path)
{
- struct dentry *old_pwd;
- struct vfsmount *old_pwdmnt;
+ struct path old_pwd;
write_lock(&fs->lock);
old_pwd = fs->pwd;
- old_pwdmnt = fs->pwdmnt;
- fs->pwdmnt = mntget(mnt);
- fs->pwd = dget(dentry);
+ fs->pwd = *path;
+ path_get(path);
write_unlock(&fs->lock);
- if (old_pwd) {
- dput(old_pwd);
- mntput(old_pwdmnt);
- }
+ if (old_pwd.dentry)
+ path_put(&old_pwd);
}
-static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd)
+static void chroot_fs_refs(struct path *old_root, struct path *new_root)
{
struct task_struct *g, *p;
struct fs_struct *fs;
if (fs) {
atomic_inc(&fs->count);
task_unlock(p);
- 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)
- set_fs_pwd(fs, new_nd->mnt, new_nd->dentry);
+ if (fs->root.dentry == old_root->dentry
+ && fs->root.mnt == old_root->mnt)
+ set_fs_root(fs, new_root);
+ if (fs->pwd.dentry == old_root->dentry
+ && fs->pwd.mnt == old_root->mnt)
+ set_fs_pwd(fs, new_root);
put_fs_struct(fs);
} else
task_unlock(p);
* 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.
+ *
* 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)
* 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)
+SYSCALL_DEFINE2(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;
+ struct path new, old, parent_path, root_parent, root;
int error;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- lock_kernel();
-
- error = __user_walk(new_root, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
- &new_nd);
+ error = user_path_dir(new_root, &new);
if (error)
goto out0;
error = -EINVAL;
- if (!check_mnt(new_nd.mnt))
+ if (!check_mnt(new.mnt))
goto out1;
- error = __user_walk(put_old, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &old_nd);
+ error = user_path_dir(put_old, &old);
if (error)
goto out1;
- error = security_sb_pivotroot(&old_nd, &new_nd);
+ error = security_sb_pivotroot(&old, &new);
if (error) {
- path_release(&old_nd);
+ path_put(&old);
goto out1;
}
read_lock(¤t->fs->lock);
- user_nd.mnt = mntget(current->fs->rootmnt);
- user_nd.dentry = dget(current->fs->root);
+ root = current->fs->root;
+ path_get(¤t->fs->root);
read_unlock(¤t->fs->lock);
down_write(&namespace_sem);
- down(&old_nd.dentry->d_inode->i_sem);
+ mutex_lock(&old.dentry->d_inode->i_mutex);
error = -EINVAL;
- if (!check_mnt(user_nd.mnt))
+ 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;
error = -ENOENT;
- if (IS_DEADDIR(new_nd.dentry->d_inode))
+ if (IS_DEADDIR(new.dentry->d_inode))
goto out2;
- if (d_unhashed(new_nd.dentry) && !IS_ROOT(new_nd.dentry))
+ if (d_unhashed(new.dentry) && !IS_ROOT(new.dentry))
goto out2;
- if (d_unhashed(old_nd.dentry) && !IS_ROOT(old_nd.dentry))
+ if (d_unhashed(old.dentry) && !IS_ROOT(old.dentry))
goto out2;
error = -EBUSY;
- if (new_nd.mnt == user_nd.mnt || old_nd.mnt == user_nd.mnt)
+ if (new.mnt == root.mnt ||
+ old.mnt == root.mnt)
goto out2; /* loop, on the same file system */
error = -EINVAL;
- if (user_nd.mnt->mnt_root != user_nd.dentry)
+ if (root.mnt->mnt_root != root.dentry)
goto out2; /* not a mountpoint */
- if (user_nd.mnt->mnt_parent == user_nd.mnt)
+ if (root.mnt->mnt_parent == root.mnt)
goto out2; /* not attached */
- if (new_nd.mnt->mnt_root != new_nd.dentry)
+ if (new.mnt->mnt_root != new.dentry)
goto out2; /* not a mountpoint */
- if (new_nd.mnt->mnt_parent == new_nd.mnt)
+ if (new.mnt->mnt_parent == new.mnt)
goto out2; /* not attached */
- tmp = old_nd.mnt; /* make sure we can reach put_old from new_root */
+ /* make sure we can reach put_old from new_root */
+ tmp = old.mnt;
spin_lock(&vfsmount_lock);
- if (tmp != new_nd.mnt) {
+ if (tmp != new.mnt) {
for (;;) {
if (tmp->mnt_parent == tmp)
goto out3; /* already mounted on put_old */
- if (tmp->mnt_parent == new_nd.mnt)
+ if (tmp->mnt_parent == new.mnt)
break;
tmp = tmp->mnt_parent;
}
- if (!is_subdir(tmp->mnt_mountpoint, new_nd.dentry))
+ if (!is_subdir(tmp->mnt_mountpoint, new.dentry))
goto out3;
- } else if (!is_subdir(old_nd.dentry, new_nd.dentry))
+ } else if (!is_subdir(old.dentry, new.dentry))
goto out3;
- detach_mnt(new_nd.mnt, &parent_nd);
- detach_mnt(user_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_namespace(current->namespace);
+ detach_mnt(new.mnt, &parent_path);
+ detach_mnt(root.mnt, &root_parent);
+ /* mount old root on put_old */
+ attach_mnt(root.mnt, &old);
+ /* mount new_root on / */
+ attach_mnt(new.mnt, &root_parent);
+ 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);
+ chroot_fs_refs(&root, &new);
+ security_sb_post_pivotroot(&root, &new);
error = 0;
- path_release(&root_parent);
- path_release(&parent_nd);
+ path_put(&root_parent);
+ path_put(&parent_path);
out2:
- up(&old_nd.dentry->d_inode->i_sem);
+ mutex_unlock(&old.dentry->d_inode->i_mutex);
up_write(&namespace_sem);
- path_release(&user_nd);
- path_release(&old_nd);
+ path_put(&root);
+ path_put(&old);
out1:
- path_release(&new_nd);
+ path_put(&new);
out0:
- unlock_kernel();
return error;
out3:
spin_unlock(&vfsmount_lock);
static void __init init_mount_tree(void)
{
struct vfsmount *mnt;
- struct namespace *namespace;
- struct task_struct *g, *p;
+ struct mnt_namespace *ns;
+ struct path root;
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_waitqueue_head(&namespace->poll);
- namespace->event = 0;
- list_add(&mnt->mnt_list, &namespace->list);
- namespace->root = mnt;
- mnt->mnt_namespace = namespace;
-
- 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);
+
+ root.mnt = ns->root;
+ root.dentry = ns->root->mnt_root;
+
+ set_fs_pwd(current->fs, &root);
+ set_fs_root(current->fs, &root);
}
-void __init mnt_init(unsigned long mempages)
+void __init mnt_init(void)
{
- struct list_head *d;
- unsigned int nr_hash;
- int i;
+ unsigned u;
+ int err;
init_rwsem(&namespace_sem);
mnt_cache = kmem_cache_create("mnt_cache", sizeof(struct vfsmount),
- 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL, NULL);
+ 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
mount_hashtable = (struct list_head *)__get_free_page(GFP_ATOMIC);
if (!mount_hashtable)
panic("Failed to allocate mount hash table\n");
- /*
- * Find the power-of-two list-heads that can fit into the allocation..
- * We don't guarantee that "sizeof(struct list_head)" is necessarily
- * a power-of-two.
- */
- nr_hash = PAGE_SIZE / sizeof(struct list_head);
- hash_bits = 0;
- do {
- hash_bits++;
- } while ((nr_hash >> hash_bits) != 0);
- hash_bits--;
+ printk("Mount-cache hash table entries: %lu\n", HASH_SIZE);
- /*
- * Re-calculate the actual number of entries and the mask
- * from the number of bits we can fit.
- */
- nr_hash = 1UL << hash_bits;
- hash_mask = nr_hash - 1;
-
- printk("Mount-cache hash table entries: %d\n", nr_hash);
-
- /* And initialize the newly allocated array */
- d = mount_hashtable;
- i = nr_hash;
- do {
- INIT_LIST_HEAD(d);
- d++;
- i--;
- } while (i);
- sysfs_init();
+ for (u = 0; u < HASH_SIZE; u++)
+ INIT_LIST_HEAD(&mount_hashtable[u]);
+
+ err = sysfs_init();
+ if (err)
+ printk(KERN_WARNING "%s: sysfs_init error: %d\n",
+ __func__, err);
+ fs_kobj = kobject_create_and_add("fs", NULL);
+ if (!fs_kobj)
+ printk(KERN_WARNING "%s: kobj create error\n", __func__);
init_rootfs();
init_mount_tree();
}
-void __put_namespace(struct namespace *namespace)
+void __put_mnt_ns(struct mnt_namespace *ns)
{
- struct vfsmount *root = namespace->root;
+ struct vfsmount *root = ns->root;
LIST_HEAD(umount_list);
- namespace->root = NULL;
+ ns->root = NULL;
spin_unlock(&vfsmount_lock);
down_write(&namespace_sem);
spin_lock(&vfsmount_lock);
- umount_tree(root, &umount_list);
+ umount_tree(root, 0, &umount_list);
spin_unlock(&vfsmount_lock);
up_write(&namespace_sem);
release_mounts(&umount_list);
- kfree(namespace);
+ kfree(ns);
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff