#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/kernel.h>
-#include <linux/quotaops.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/mnt_namespace.h>
#include <linux/namei.h>
+#include <linux/nsproxy.h>
#include <linux/security.h>
#include <linux/mount.h>
#include <linux/ramfs.h>
#include <linux/log2.h>
+#include <linux/idr.h>
+#include <linux/fs_struct.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include "pnode.h"
__cacheline_aligned_in_smp DEFINE_SPINLOCK(vfsmount_lock);
static int event;
+static DEFINE_IDA(mnt_id_ida);
+static DEFINE_IDA(mnt_group_ida);
+static int mnt_id_start = 0;
+static int mnt_group_start = 1;
static struct list_head *mount_hashtable __read_mostly;
static struct kmem_cache *mnt_cache __read_mostly;
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_above(&mnt_id_ida, mnt_id_start, &mnt->mnt_id);
+ if (!res)
+ mnt_id_start = mnt->mnt_id + 1;
+ spin_unlock(&vfsmount_lock);
+ if (res == -EAGAIN)
+ goto retry;
+
+ return res;
+}
+
+static void mnt_free_id(struct vfsmount *mnt)
+{
+ int id = mnt->mnt_id;
+ spin_lock(&vfsmount_lock);
+ ida_remove(&mnt_id_ida, id);
+ if (mnt_id_start > id)
+ mnt_id_start = 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)
+{
+ int res;
+
+ if (!ida_pre_get(&mnt_group_ida, GFP_KERNEL))
+ return -ENOMEM;
+
+ res = ida_get_new_above(&mnt_group_ida,
+ mnt_group_start,
+ &mnt->mnt_group_id);
+ if (!res)
+ mnt_group_start = mnt->mnt_group_id + 1;
+
+ return res;
+}
+
+/*
+ * Release a peer group ID
+ */
+void mnt_release_group_id(struct vfsmount *mnt)
+{
+ int id = mnt->mnt_group_id;
+ ida_remove(&mnt_group_ida, id);
+ if (mnt_group_start > id)
+ mnt_group_start = id;
+ mnt->mnt_group_id = 0;
+}
+
struct vfsmount *alloc_vfsmnt(const char *name)
{
struct vfsmount *mnt = kmem_cache_zalloc(mnt_cache, GFP_KERNEL);
if (mnt) {
+ 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_share);
INIT_LIST_HEAD(&mnt->mnt_slave_list);
INIT_LIST_HEAD(&mnt->mnt_slave);
- if (name) {
- int size = strlen(name) + 1;
- char *newname = kmalloc(size, GFP_KERNEL);
- if (newname) {
- memcpy(newname, name, size);
- mnt->mnt_devname = newname;
- }
- }
+#ifdef CONFIG_SMP
+ mnt->mnt_writers = alloc_percpu(int);
+ if (!mnt->mnt_writers)
+ goto out_free_devname;
+#else
+ mnt->mnt_writers = 0;
+#endif
}
return mnt;
+
+#ifdef CONFIG_SMP
+out_free_devname:
+ kfree(mnt->mnt_devname);
+#endif
+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);
+
+static inline void inc_mnt_writers(struct vfsmount *mnt)
+{
+#ifdef CONFIG_SMP
+ (*per_cpu_ptr(mnt->mnt_writers, smp_processor_id()))++;
+#else
+ mnt->mnt_writers++;
+#endif
+}
+
+static inline void dec_mnt_writers(struct vfsmount *mnt)
+{
+#ifdef CONFIG_SMP
+ (*per_cpu_ptr(mnt->mnt_writers, smp_processor_id()))--;
+#else
+ mnt->mnt_writers--;
+#endif
+}
+
+static unsigned int count_mnt_writers(struct vfsmount *mnt)
+{
+#ifdef CONFIG_SMP
+ unsigned int count = 0;
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ count += *per_cpu_ptr(mnt->mnt_writers, cpu);
+ }
+
+ return count;
+#else
+ return mnt->mnt_writers;
+#endif
+}
+
+/*
+ * 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;
+
+ preempt_disable();
+ inc_mnt_writers(mnt);
+ /*
+ * The store to inc_mnt_writers must be visible before we pass
+ * MNT_WRITE_HOLD loop below, so that the slowpath can see our
+ * incremented count after it has set MNT_WRITE_HOLD.
+ */
+ smp_mb();
+ while (mnt->mnt_flags & MNT_WRITE_HOLD)
+ cpu_relax();
+ /*
+ * After the slowpath clears MNT_WRITE_HOLD, mnt_is_readonly will
+ * be set to match its requirements. So we must not load that until
+ * MNT_WRITE_HOLD is cleared.
+ */
+ smp_rmb();
+ if (__mnt_is_readonly(mnt)) {
+ dec_mnt_writers(mnt);
+ ret = -EROFS;
+ goto out;
+ }
+out:
+ preempt_enable();
+ return ret;
+}
+EXPORT_SYMBOL_GPL(mnt_want_write);
+
+/**
+ * mnt_clone_write - get write access to a mount
+ * @mnt: the mount on which to take a write
+ *
+ * This is effectively like mnt_want_write, except
+ * it must only be used to take an extra write reference
+ * on a mountpoint that we already know has a write reference
+ * on it. This allows some optimisation.
+ *
+ * After finished, mnt_drop_write must be called as usual to
+ * drop the reference.
+ */
+int mnt_clone_write(struct vfsmount *mnt)
+{
+ /* superblock may be r/o */
+ if (__mnt_is_readonly(mnt))
+ return -EROFS;
+ preempt_disable();
+ inc_mnt_writers(mnt);
+ preempt_enable();
+ return 0;
+}
+EXPORT_SYMBOL_GPL(mnt_clone_write);
+
+/**
+ * mnt_want_write_file - get write access to a file's mount
+ * @file: the file who's mount on which to take a write
+ *
+ * This is like mnt_want_write, but it takes a file and can
+ * do some optimisations if the file is open for write already
+ */
+int mnt_want_write_file(struct file *file)
+{
+ struct inode *inode = file->f_dentry->d_inode;
+ if (!(file->f_mode & FMODE_WRITE) || special_file(inode->i_mode))
+ return mnt_want_write(file->f_path.mnt);
+ else
+ return mnt_clone_write(file->f_path.mnt);
+}
+EXPORT_SYMBOL_GPL(mnt_want_write_file);
+
+/**
+ * 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)
+{
+ preempt_disable();
+ dec_mnt_writers(mnt);
+ preempt_enable();
+}
+EXPORT_SYMBOL_GPL(mnt_drop_write);
+
+static int mnt_make_readonly(struct vfsmount *mnt)
+{
+ int ret = 0;
+
+ spin_lock(&vfsmount_lock);
+ mnt->mnt_flags |= MNT_WRITE_HOLD;
+ /*
+ * After storing MNT_WRITE_HOLD, we'll read the counters. This store
+ * should be visible before we do.
+ */
+ smp_mb();
+
+ /*
+ * With writers on hold, if this value is zero, then there are
+ * definitely no active writers (although held writers may subsequently
+ * increment the count, they'll have to wait, and decrement it after
+ * seeing MNT_READONLY).
+ *
+ * It is OK to have counter incremented on one CPU and decremented on
+ * another: the sum will add up correctly. The danger would be when we
+ * sum up each counter, if we read a counter before it is incremented,
+ * but then read another CPU's count which it has been subsequently
+ * decremented from -- we would see more decrements than we should.
+ * MNT_WRITE_HOLD protects against this scenario, because
+ * mnt_want_write first increments count, then smp_mb, then spins on
+ * MNT_WRITE_HOLD, so it can't be decremented by another CPU while
+ * we're counting up here.
+ */
+ if (count_mnt_writers(mnt) > 0)
+ ret = -EBUSY;
+ else
+ mnt->mnt_flags |= MNT_READONLY;
+ /*
+ * MNT_READONLY must become visible before ~MNT_WRITE_HOLD, so writers
+ * that become unheld will see MNT_READONLY.
+ */
+ smp_wmb();
+ mnt->mnt_flags &= ~MNT_WRITE_HOLD;
+ spin_unlock(&vfsmount_lock);
+ 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)
+void 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);
+#ifdef CONFIG_SMP
+ free_percpu(mnt->mnt_writers);
+#endif
kmem_cache_free(mnt_cache, mnt);
}
* lookup_mnt increments the ref count before returning
* the vfsmount struct.
*/
-struct vfsmount *lookup_mnt(struct vfsmount *mnt, struct dentry *dentry)
+struct vfsmount *lookup_mnt(struct path *path)
{
struct vfsmount *child_mnt;
spin_lock(&vfsmount_lock);
- if ((child_mnt = __lookup_mnt(mnt, dentry, 1)))
+ if ((child_mnt = __lookup_mnt(path->mnt, path->dentry, 1)))
mntget(child_mnt);
spin_unlock(&vfsmount_lock);
return child_mnt;
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_master = old;
CLEAR_MNT_SHARED(mnt);
} else if (!(flag & CL_PRIVATE)) {
- if ((flag & CL_PROPAGATION) || IS_MNT_SHARED(old))
+ if ((flag & CL_MAKE_SHARED) || 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);
}
}
return mnt;
+
+ out_free:
+ free_vfsmnt(mnt);
+ return NULL;
}
static inline void __mntput(struct vfsmount *mnt)
{
struct super_block *sb = mnt->mnt_sb;
+ /*
+ * 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.
+ */
+ /*
+ * atomic_dec_and_lock() used to deal with ->mnt_count decrements
+ * provides barriers, so count_mnt_writers() below is safe. AV
+ */
+ WARN_ON(count_mnt_writers(mnt));
dput(mnt->mnt_root);
free_vfsmnt(mnt);
deactivate_super(sb);
mnt->mnt_pinned = 0;
spin_unlock(&vfsmount_lock);
acct_auto_close_mnt(mnt);
- security_sb_umount_close(mnt);
goto repeat;
}
}
*/
int generic_show_options(struct seq_file *m, struct vfsmount *mnt)
{
- const char *options = mnt->mnt_sb->s_options;
+ const char *options;
+
+ rcu_read_lock();
+ options = rcu_dereference(mnt->mnt_sb->s_options);
if (options != NULL && options[0]) {
seq_putc(m, ',');
mangle(m, options);
}
+ rcu_read_unlock();
return 0;
}
*/
void save_mount_options(struct super_block *sb, char *options)
{
- kfree(sb->s_options);
- sb->s_options = kstrdup(options, GFP_KERNEL);
+ BUG_ON(sb->s_options);
+ rcu_assign_pointer(sb->s_options, kstrdup(options, GFP_KERNEL));
}
EXPORT_SYMBOL(save_mount_options);
+void replace_mount_options(struct super_block *sb, char *options)
+{
+ char *old = sb->s_options;
+ rcu_assign_pointer(sb->s_options, options);
+ if (old) {
+ synchronize_rcu();
+ kfree(old);
+ }
+}
+EXPORT_SYMBOL(replace_mount_options);
+
+#ifdef CONFIG_PROC_FS
/* iterator */
static void *m_start(struct seq_file *m, loff_t *pos)
{
- struct mnt_namespace *n = m->private;
+ struct proc_mounts *p = m->private;
down_read(&namespace_sem);
- return seq_list_start(&n->list, *pos);
+ return seq_list_start(&p->ns->list, *pos);
}
static void *m_next(struct seq_file *m, void *v, loff_t *pos)
{
- struct mnt_namespace *n = m->private;
+ struct proc_mounts *p = m->private;
- return seq_list_next(v, &n->list, pos);
+ return seq_list_next(v, &p->ns->list, pos);
}
static void m_stop(struct seq_file *m, void *v)
up_read(&namespace_sem);
}
-static int show_vfsmnt(struct seq_file *m, void *v)
+int mnt_had_events(struct proc_mounts *p)
{
- struct vfsmount *mnt = list_entry(v, struct vfsmount, mnt_list);
- int err = 0;
- static struct proc_fs_info {
- int flag;
- char *str;
- } fs_info[] = {
+ struct mnt_namespace *ns = p->ns;
+ int res = 0;
+
+ spin_lock(&vfsmount_lock);
+ if (p->event != ns->event) {
+ p->event = ns->event;
+ res = 1;
+ }
+ spin_unlock(&vfsmount_lock);
+
+ return res;
+}
+
+struct proc_fs_info {
+ int flag;
+ const char *str;
+};
+
+static int show_sb_opts(struct seq_file *m, struct super_block *sb)
+{
+ static const struct proc_fs_info fs_info[] = {
{ MS_SYNCHRONOUS, ",sync" },
{ MS_DIRSYNC, ",dirsync" },
{ MS_MANDLOCK, ",mand" },
{ 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" },
+ { MNT_STRICTATIME, ",strictatime" },
{ 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_path, " \t\n\\");
seq_putc(m, ' ');
- mangle(m, mnt->mnt_sb->s_type->name);
- if (mnt->mnt_sb->s_subtype && mnt->mnt_sb->s_subtype[0]) {
- seq_putc(m, '.');
- mangle(m, mnt->mnt_sb->s_subtype);
- }
- 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);
- }
- for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) {
- if (mnt->mnt_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;
}
-struct seq_operations mounts_op = {
+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;
+ }
+ 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);
/* file system type */
seq_puts(m, "with fstype ");
- mangle(m, mnt->mnt_sb->s_type->name);
+ show_type(m, mnt->mnt_sb);
/* optional statistics */
if (mnt->mnt_sb->s_op->show_stats) {
return err;
}
-struct seq_operations mountstats_op = {
+const struct seq_operations mountstats_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = show_vfsstat,
};
+#endif /* CONFIG_PROC_FS */
/**
* may_umount_tree - check if a mount tree is busy
int may_umount(struct vfsmount *mnt)
{
int ret = 1;
+ down_read(&namespace_sem);
spin_lock(&vfsmount_lock);
if (propagate_mount_busy(mnt, 2))
ret = 0;
spin_unlock(&vfsmount_lock);
+ up_read(&namespace_sem);
return ret;
}
* about for the moment.
*/
- lock_kernel();
- if (sb->s_op->umount_begin)
- sb->s_op->umount_begin(mnt, flags);
- unlock_kernel();
+ if (flags & MNT_FORCE && sb->s_op->umount_begin) {
+ sb->s_op->umount_begin(sb);
+ }
/*
* No sense to grab the lock for this test, but test itself looks
* we just try to remount it readonly.
*/
down_write(&sb->s_umount);
- if (!(sb->s_flags & MS_RDONLY)) {
- lock_kernel();
- DQUOT_OFF(sb);
+ if (!(sb->s_flags & MS_RDONLY))
retval = do_remount_sb(sb, MS_RDONLY, NULL, 0);
- unlock_kernel();
- }
up_write(&sb->s_umount);
return retval;
}
retval = 0;
}
spin_unlock(&vfsmount_lock);
- if (retval)
- security_sb_umount_busy(mnt);
up_write(&namespace_sem);
release_mounts(&umount_list);
return retval;
* 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;
+ int lookup_flags = 0;
- retval = __user_walk(name, LOOKUP_FOLLOW, &nd);
+ if (flags & ~(MNT_FORCE | MNT_DETACH | MNT_EXPIRE | UMOUNT_NOFOLLOW))
+ return -EINVAL;
+
+ if (!(flags & UMOUNT_NOFOLLOW))
+ lookup_flags |= LOOKUP_FOLLOW;
+
+ retval = user_path_at(AT_FDCWD, name, lookup_flags, &path);
if (retval)
goto out;
retval = -EINVAL;
- if (nd.path.dentry != nd.path.mnt->mnt_root)
+ if (path.dentry != path.mnt->mnt_root)
goto dput_and_out;
- if (!check_mnt(nd.path.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.path.mnt, flags);
+ retval = do_umount(path.mnt, flags);
dput_and_out:
/* we mustn't call path_put() as that would clear mnt_expiry_mark */
- dput(nd.path.dentry);
- mntput_no_expire(nd.path.mnt);
+ 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->path.dentry->d_inode->i_mode))
+ if (S_ISLNK(path->dentry->d_inode->i_mode))
return -EPERM;
- if (nd->path.dentry->d_inode->i_mode & S_ISVTX) {
- if (current->uid != nd->path.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 (vfs_permission(nd, MAY_WRITE))
+ 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;
- }
-}
-
struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry,
int flag)
{
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)) {
return NULL;
}
-struct vfsmount *collect_mounts(struct vfsmount *mnt, struct dentry *dentry)
+struct vfsmount *collect_mounts(struct path *path)
{
struct vfsmount *tree;
- down_read(&namespace_sem);
- tree = copy_tree(mnt, dentry, CL_COPY_ALL | CL_PRIVATE);
- up_read(&namespace_sem);
+ down_write(&namespace_sem);
+ tree = copy_tree(path->mnt, path->dentry, CL_COPY_ALL | CL_PRIVATE);
+ up_write(&namespace_sem);
return tree;
}
void drop_collected_mounts(struct vfsmount *mnt)
{
LIST_HEAD(umount_list);
- down_read(&namespace_sem);
+ down_write(&namespace_sem);
spin_lock(&vfsmount_lock);
umount_tree(mnt, 0, &umount_list);
spin_unlock(&vfsmount_lock);
- up_read(&namespace_sem);
+ up_write(&namespace_sem);
release_mounts(&umount_list);
}
+int iterate_mounts(int (*f)(struct vfsmount *, void *), void *arg,
+ struct vfsmount *root)
+{
+ struct vfsmount *mnt;
+ int res = f(root, arg);
+ if (res)
+ return res;
+ list_for_each_entry(mnt, &root->mnt_list, mnt_list) {
+ res = f(mnt, arg);
+ if (res)
+ return res;
+ }
+ return 0;
+}
+
+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
struct vfsmount *dest_mnt = path->mnt;
struct dentry *dest_dentry = path->dentry;
struct vfsmount *child, *p;
+ int err;
- if (propagate_mnt(dest_mnt, dest_dentry, source_mnt, &tree_list))
- return -EINVAL;
+ 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;
+
+ spin_lock(&vfsmount_lock);
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);
+ touch_mnt_namespace(parent_path->mnt->mnt_ns);
} else {
mnt_set_mountpoint(dest_mnt, dest_dentry, source_mnt);
commit_tree(source_mnt);
}
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 nameidata *nd)
+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->path.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;
- mutex_lock(&nd->path.dentry->d_inode->i_mutex);
- if (IS_DEADDIR(nd->path.dentry->d_inode))
- goto out_unlock;
-
- err = security_sb_check_sb(mnt, nd);
- if (err)
+ mutex_lock(&path->dentry->d_inode->i_mutex);
+ if (cant_mount(path->dentry))
goto out_unlock;
- err = -ENOENT;
- if (IS_ROOT(nd->path.dentry) || !d_unhashed(nd->path.dentry))
- err = attach_recursive_mnt(mnt, &nd->path, NULL);
+ if (!d_unlinked(path->dentry))
+ err = attach_recursive_mnt(mnt, path, NULL);
out_unlock:
- mutex_unlock(&nd->path.dentry->d_inode->i_mutex);
- if (!err)
- security_sb_post_addmount(mnt, nd);
+ mutex_unlock(&path->dentry->d_inode->i_mutex);
return err;
}
/*
* recursively change the type of the mountpoint.
- * noinline this do_mount helper to save do_mount stack space.
*/
-static noinline int do_change_type(struct nameidata *nd, int flag)
+static int do_change_type(struct path *path, int flag)
{
- struct vfsmount *m, *mnt = nd->path.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->path.dentry != nd->path.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.
- * noinline this do_mount helper to save do_mount stack space.
*/
-static noinline int do_loopback(struct nameidata *nd, char *old_name,
+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 (IS_MNT_UNBINDABLE(old_nd.path.mnt))
+ if (IS_MNT_UNBINDABLE(old_path.mnt))
goto out;
- if (!check_mnt(nd->path.mnt) || !check_mnt(old_nd.path.mnt))
+ if (!check_mnt(path->mnt) || !check_mnt(old_path.mnt))
goto out;
err = -ENOMEM;
if (recurse)
- mnt = copy_tree(old_nd.path.mnt, old_nd.path.dentry, 0);
+ mnt = copy_tree(old_path.mnt, old_path.dentry, 0);
else
- mnt = clone_mnt(old_nd.path.mnt, old_nd.path.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);
out:
up_write(&namespace_sem);
- path_put(&old_nd.path);
+ 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.
- * noinline this do_mount helper to save do_mount stack space.
*/
-static noinline 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->path.mnt->mnt_sb;
+ struct super_block *sb = path->mnt->mnt_sb;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- if (!check_mnt(nd->path.mnt))
+ if (!check_mnt(path->mnt))
return -EINVAL;
- if (nd->path.dentry != nd->path.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 (!err)
- nd->path.mnt->mnt_flags = mnt_flags;
+ if (flags & MS_BIND)
+ err = change_mount_flags(path->mnt, flags);
+ else
+ err = do_remount_sb(sb, flags, data, 0);
+ if (!err) {
+ spin_lock(&vfsmount_lock);
+ mnt_flags |= path->mnt->mnt_flags & MNT_PROPAGATION_MASK;
+ path->mnt->mnt_flags = mnt_flags;
+ spin_unlock(&vfsmount_lock);
+ }
up_write(&sb->s_umount);
- if (!err)
- security_sb_post_remount(nd->path.mnt, flags, data);
+ if (!err) {
+ spin_lock(&vfsmount_lock);
+ touch_mnt_namespace(path->mnt->mnt_ns);
+ spin_unlock(&vfsmount_lock);
+ }
return err;
}
return 0;
}
-/*
- * noinline this do_mount helper to save do_mount stack space.
- */
-static noinline int do_move_mount(struct nameidata *nd, char *old_name)
+static int do_move_mount(struct path *path, char *old_name)
{
- struct nameidata old_nd;
- struct path parent_path;
+ 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->path.dentry) &&
- follow_down(&nd->path.mnt, &nd->path.dentry))
+ while (d_mountpoint(path->dentry) &&
+ follow_down(path))
;
err = -EINVAL;
- if (!check_mnt(nd->path.mnt) || !check_mnt(old_nd.path.mnt))
+ if (!check_mnt(path->mnt) || !check_mnt(old_path.mnt))
goto out;
err = -ENOENT;
- mutex_lock(&nd->path.dentry->d_inode->i_mutex);
- if (IS_DEADDIR(nd->path.dentry->d_inode))
+ mutex_lock(&path->dentry->d_inode->i_mutex);
+ if (cant_mount(path->dentry))
goto out1;
- if (!IS_ROOT(nd->path.dentry) && d_unhashed(nd->path.dentry))
+ if (d_unlinked(path->dentry))
goto out1;
err = -EINVAL;
- if (old_nd.path.dentry != old_nd.path.mnt->mnt_root)
+ if (old_path.dentry != old_path.mnt->mnt_root)
goto out1;
- if (old_nd.path.mnt == old_nd.path.mnt->mnt_parent)
+ if (old_path.mnt == old_path.mnt->mnt_parent)
goto out1;
- if (S_ISDIR(nd->path.dentry->d_inode->i_mode) !=
- S_ISDIR(old_nd.path.dentry->d_inode->i_mode))
+ 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_nd.path.mnt->mnt_parent &&
- IS_MNT_SHARED(old_nd.path.mnt->mnt_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(nd->path.mnt) &&
- tree_contains_unbindable(old_nd.path.mnt))
+ if (IS_MNT_SHARED(path->mnt) &&
+ tree_contains_unbindable(old_path.mnt))
goto out1;
err = -ELOOP;
- for (p = nd->path.mnt; p->mnt_parent != p; p = p->mnt_parent)
- if (p == old_nd.path.mnt)
+ for (p = path->mnt; p->mnt_parent != p; p = p->mnt_parent)
+ if (p == old_path.mnt)
goto out1;
- err = attach_recursive_mnt(old_nd.path.mnt, &nd->path, &parent_path);
+ 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.path.mnt->mnt_expire);
+ list_del_init(&old_path.mnt->mnt_expire);
out1:
- mutex_unlock(&nd->path.dentry->d_inode->i_mutex);
+ mutex_unlock(&path->dentry->d_inode->i_mutex);
out:
up_write(&namespace_sem);
if (!err)
path_put(&parent_path);
- path_put(&old_nd.path);
+ path_put(&old_path);
return err;
}
/*
* create a new mount for userspace and request it to be added into the
* namespace's tree
- * noinline this do_mount helper to save do_mount stack space.
*/
-static noinline 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 (!type || !memchr(type, 0, PAGE_SIZE))
+ if (!type)
return -EINVAL;
/* we need capabilities... */
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
+ lock_kernel();
mnt = do_kern_mount(type, flags, name, data);
+ unlock_kernel();
if (IS_ERR(mnt))
return PTR_ERR(mnt);
- 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;
+ mnt_flags &= ~(MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL);
+
down_write(&namespace_sem);
/* Something was mounted here while we slept */
- while (d_mountpoint(nd->path.dentry) &&
- follow_down(&nd->path.mnt, &nd->path.dentry))
+ while (d_mountpoint(path->dentry) &&
+ follow_down(path))
;
err = -EINVAL;
- if (!check_mnt(nd->path.mnt))
+ if (!(mnt_flags & MNT_SHRINKABLE) && !check_mnt(path->mnt))
goto unlock;
/* Refuse the same filesystem on the same mount point */
err = -EBUSY;
- if (nd->path.mnt->mnt_sb == newmnt->mnt_sb &&
- nd->path.mnt->mnt_root == nd->path.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 */
while (!list_empty(&graveyard)) {
m = list_first_entry(&graveyard, struct vfsmount,
mnt_expire);
- touch_mnt_namespace(mnt->mnt_ns);
- umount_tree(mnt, 1, umounts);
+ touch_mnt_namespace(m->mnt_ns);
+ umount_tree(m, 1, umounts);
}
}
}
return 0;
}
+int copy_mount_string(const void __user *data, char **where)
+{
+ char *tmp;
+
+ if (!data) {
+ *where = NULL;
+ return 0;
+ }
+
+ tmp = strndup_user(data, PAGE_SIZE);
+ if (IS_ERR(tmp))
+ return PTR_ERR(tmp);
+
+ *where = tmp;
+ return 0;
+}
+
/*
* Flags is a 32-bit value that allows up to 31 non-fs dependent flags to
* be given to the mount() call (ie: read-only, no-dev, no-suid etc).
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;
if (!dir_name || !*dir_name || !memchr(dir_name, 0, PAGE_SIZE))
return -EINVAL;
- if (dev_name && !memchr(dev_name, 0, PAGE_SIZE))
- return -EINVAL;
if (data_page)
((char *)data_page)[PAGE_SIZE - 1] = 0;
+ /* ... and get the mountpoint */
+ retval = kern_path(dir_name, LOOKUP_FOLLOW, &path);
+ if (retval)
+ return retval;
+
+ retval = security_sb_mount(dev_name, &path,
+ type_page, flags, data_page);
+ if (retval)
+ goto dput_out;
+
+ /* Default to relatime unless overriden */
+ if (!(flags & MS_NOATIME))
+ mnt_flags |= MNT_RELATIME;
+
/* Separate the per-mountpoint flags */
if (flags & MS_NOSUID)
mnt_flags |= MNT_NOSUID;
mnt_flags |= MNT_NOATIME;
if (flags & MS_NODIRATIME)
mnt_flags |= MNT_NODIRATIME;
- if (flags & MS_RELATIME)
- mnt_flags |= MNT_RELATIME;
+ if (flags & MS_STRICTATIME)
+ mnt_flags &= ~(MNT_RELATIME | MNT_NOATIME);
+ 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);
- if (retval)
- return retval;
-
- retval = security_sb_mount(dev_name, &nd, type_page, flags, data_page);
- if (retval)
- goto dput_out;
+ MS_NOATIME | MS_NODIRATIME | MS_RELATIME| MS_KERNMOUNT |
+ MS_STRICTATIME);
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);
+ retval = do_loopback(&path, dev_name, flags & MS_REC);
else if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
- retval = do_change_type(&nd, flags);
+ 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_put(&nd.path);
+ path_put(&path);
return retval;
}
-/*
- * 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)
+static struct mnt_namespace *alloc_mnt_ns(void)
{
struct mnt_namespace *new_ns;
- struct vfsmount *rootmnt = NULL, *pwdmnt = NULL, *altrootmnt = NULL;
- struct vfsmount *p, *q;
new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL);
if (!new_ns)
return ERR_PTR(-ENOMEM);
-
atomic_set(&new_ns->count, 1);
+ new_ns->root = NULL;
INIT_LIST_HEAD(&new_ns->list);
init_waitqueue_head(&new_ns->poll);
new_ns->event = 0;
+ return new_ns;
+}
+
+/*
+ * Allocate a new namespace structure and populate it with contents
+ * copied from the namespace of the passed in task structure.
+ */
+static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns,
+ struct fs_struct *fs)
+{
+ struct mnt_namespace *new_ns;
+ struct vfsmount *rootmnt = NULL, *pwdmnt = NULL;
+ struct vfsmount *p, *q;
+
+ new_ns = alloc_mnt_ns();
+ if (IS_ERR(new_ns))
+ return new_ns;
down_write(&namespace_sem);
/* First pass: copy the tree topology */
if (!new_ns->root) {
up_write(&namespace_sem);
kfree(new_ns);
- return ERR_PTR(-ENOMEM);;
+ return ERR_PTR(-ENOMEM);
}
spin_lock(&vfsmount_lock);
list_add_tail(&new_ns->list, &new_ns->root->mnt_list);
pwdmnt = p;
fs->pwd.mnt = mntget(q);
}
- if (p == fs->altroot.mnt) {
- altrootmnt = p;
- fs->altroot.mnt = mntget(q);
- }
}
p = next_mnt(p, mnt_ns->root);
q = next_mnt(q, new_ns->root);
mntput(rootmnt);
if (pwdmnt)
mntput(pwdmnt);
- if (altrootmnt)
- mntput(altrootmnt);
return new_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)
+/**
+ * create_mnt_ns - creates a private namespace and adds a root filesystem
+ * @mnt: pointer to the new root filesystem mountpoint
+ */
+struct mnt_namespace *create_mnt_ns(struct vfsmount *mnt)
{
- int retval;
- unsigned long data_page;
- unsigned long type_page;
- unsigned long dev_page;
- char *dir_page;
-
- retval = copy_mount_options(type, &type_page);
- if (retval < 0)
- return retval;
-
- dir_page = getname(dir_name);
- retval = PTR_ERR(dir_page);
- if (IS_ERR(dir_page))
- goto out1;
-
- retval = copy_mount_options(dev_name, &dev_page);
- if (retval < 0)
- goto out2;
-
- 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);
- unlock_kernel();
- free_page(data_page);
+ struct mnt_namespace *new_ns;
-out3:
- free_page(dev_page);
-out2:
- putname(dir_page);
-out1:
- free_page(type_page);
- return retval;
+ new_ns = alloc_mnt_ns();
+ if (!IS_ERR(new_ns)) {
+ mnt->mnt_ns = new_ns;
+ new_ns->root = mnt;
+ list_add(&new_ns->list, &new_ns->root->mnt_list);
+ }
+ return new_ns;
}
+EXPORT_SYMBOL(create_mnt_ns);
-/*
- * 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 path *path)
+SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name,
+ char __user *, type, unsigned long, flags, void __user *, data)
{
- struct path old_root;
+ int ret;
+ char *kernel_type;
+ char *kernel_dir;
+ char *kernel_dev;
+ unsigned long data_page;
- write_lock(&fs->lock);
- old_root = fs->root;
- fs->root = *path;
- path_get(path);
- write_unlock(&fs->lock);
- if (old_root.dentry)
- path_put(&old_root);
-}
+ ret = copy_mount_string(type, &kernel_type);
+ if (ret < 0)
+ goto out_type;
-/*
- * 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 path *path)
-{
- struct path old_pwd;
+ kernel_dir = getname(dir_name);
+ if (IS_ERR(kernel_dir)) {
+ ret = PTR_ERR(kernel_dir);
+ goto out_dir;
+ }
- write_lock(&fs->lock);
- old_pwd = fs->pwd;
- fs->pwd = *path;
- path_get(path);
- write_unlock(&fs->lock);
+ ret = copy_mount_string(dev_name, &kernel_dev);
+ if (ret < 0)
+ goto out_dev;
- if (old_pwd.dentry)
- path_put(&old_pwd);
-}
+ ret = copy_mount_options(data, &data_page);
+ if (ret < 0)
+ goto out_data;
-static void chroot_fs_refs(struct path *old_root, struct path *new_root)
-{
- struct task_struct *g, *p;
- struct fs_struct *fs;
+ ret = do_mount(kernel_dev, kernel_dir, kernel_type, flags,
+ (void *) data_page);
- read_lock(&tasklist_lock);
- do_each_thread(g, p) {
- task_lock(p);
- fs = p->fs;
- if (fs) {
- atomic_inc(&fs->count);
- task_unlock(p);
- 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);
- } while_each_thread(g, p);
- read_unlock(&tasklist_lock);
+ free_page(data_page);
+out_data:
+ kfree(kernel_dev);
+out_dev:
+ putname(kernel_dir);
+out_dir:
+ kfree(kernel_type);
+out_type:
+ return ret;
}
/*
* 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, user_nd;
- struct path parent_path, root_parent;
+ 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.path.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_put(&old_nd.path);
+ path_put(&old);
goto out1;
}
read_lock(¤t->fs->lock);
- user_nd.path = current->fs->root;
+ root = current->fs->root;
path_get(¤t->fs->root);
read_unlock(¤t->fs->lock);
down_write(&namespace_sem);
- mutex_lock(&old_nd.path.dentry->d_inode->i_mutex);
+ mutex_lock(&old.dentry->d_inode->i_mutex);
error = -EINVAL;
- if (IS_MNT_SHARED(old_nd.path.mnt) ||
- IS_MNT_SHARED(new_nd.path.mnt->mnt_parent) ||
- IS_MNT_SHARED(user_nd.path.mnt->mnt_parent))
+ 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(user_nd.path.mnt))
+ if (!check_mnt(root.mnt))
goto out2;
error = -ENOENT;
- if (IS_DEADDIR(new_nd.path.dentry->d_inode))
+ if (cant_mount(old.dentry))
goto out2;
- if (d_unhashed(new_nd.path.dentry) && !IS_ROOT(new_nd.path.dentry))
+ if (d_unlinked(new.dentry))
goto out2;
- if (d_unhashed(old_nd.path.dentry) && !IS_ROOT(old_nd.path.dentry))
+ if (d_unlinked(old.dentry))
goto out2;
error = -EBUSY;
- if (new_nd.path.mnt == user_nd.path.mnt ||
- old_nd.path.mnt == user_nd.path.mnt)
+ if (new.mnt == root.mnt ||
+ old.mnt == root.mnt)
goto out2; /* loop, on the same file system */
error = -EINVAL;
- if (user_nd.path.mnt->mnt_root != user_nd.path.dentry)
+ if (root.mnt->mnt_root != root.dentry)
goto out2; /* not a mountpoint */
- if (user_nd.path.mnt->mnt_parent == user_nd.path.mnt)
+ if (root.mnt->mnt_parent == root.mnt)
goto out2; /* not attached */
- if (new_nd.path.mnt->mnt_root != new_nd.path.dentry)
+ if (new.mnt->mnt_root != new.dentry)
goto out2; /* not a mountpoint */
- if (new_nd.path.mnt->mnt_parent == new_nd.path.mnt)
+ if (new.mnt->mnt_parent == new.mnt)
goto out2; /* not attached */
/* make sure we can reach put_old from new_root */
- tmp = old_nd.path.mnt;
+ tmp = old.mnt;
spin_lock(&vfsmount_lock);
- if (tmp != new_nd.path.mnt) {
+ if (tmp != new.mnt) {
for (;;) {
if (tmp->mnt_parent == tmp)
goto out3; /* already mounted on put_old */
- if (tmp->mnt_parent == new_nd.path.mnt)
+ if (tmp->mnt_parent == new.mnt)
break;
tmp = tmp->mnt_parent;
}
- if (!is_subdir(tmp->mnt_mountpoint, new_nd.path.dentry))
+ if (!is_subdir(tmp->mnt_mountpoint, new.dentry))
goto out3;
- } else if (!is_subdir(old_nd.path.dentry, new_nd.path.dentry))
+ } else if (!is_subdir(old.dentry, new.dentry))
goto out3;
- detach_mnt(new_nd.path.mnt, &parent_path);
- detach_mnt(user_nd.path.mnt, &root_parent);
+ detach_mnt(new.mnt, &parent_path);
+ detach_mnt(root.mnt, &root_parent);
/* mount old root on put_old */
- attach_mnt(user_nd.path.mnt, &old_nd.path);
+ attach_mnt(root.mnt, &old);
/* mount new_root on / */
- attach_mnt(new_nd.path.mnt, &root_parent);
+ attach_mnt(new.mnt, &root_parent);
touch_mnt_namespace(current->nsproxy->mnt_ns);
spin_unlock(&vfsmount_lock);
- chroot_fs_refs(&user_nd.path, &new_nd.path);
- security_sb_post_pivotroot(&user_nd, &new_nd);
+ chroot_fs_refs(&root, &new);
error = 0;
path_put(&root_parent);
path_put(&parent_path);
out2:
- mutex_unlock(&old_nd.path.dentry->d_inode->i_mutex);
+ mutex_unlock(&old.dentry->d_inode->i_mutex);
up_write(&namespace_sem);
- path_put(&user_nd.path);
- path_put(&old_nd.path);
+ path_put(&root);
+ path_put(&old);
out1:
- path_put(&new_nd.path);
+ path_put(&new);
out0:
- unlock_kernel();
return error;
out3:
spin_unlock(&vfsmount_lock);
mnt = do_kern_mount("rootfs", 0, "rootfs", NULL);
if (IS_ERR(mnt))
panic("Can't create rootfs");
- ns = kmalloc(sizeof(*ns), GFP_KERNEL);
- if (!ns)
+ ns = create_mnt_ns(mnt);
+ if (IS_ERR(ns))
panic("Can't allocate initial namespace");
- atomic_set(&ns->count, 1);
- INIT_LIST_HEAD(&ns->list);
- init_waitqueue_head(&ns->poll);
- ns->event = 0;
- list_add(&mnt->mnt_list, &ns->list);
- ns->root = mnt;
- mnt->mnt_ns = ns;
init_task.nsproxy->mnt_ns = ns;
get_mnt_ns(ns);
err = sysfs_init();
if (err)
printk(KERN_WARNING "%s: sysfs_init error: %d\n",
- __FUNCTION__, err);
+ __func__, err);
fs_kobj = kobject_create_and_add("fs", NULL);
if (!fs_kobj)
- printk(KERN_WARNING "%s: kobj create error\n", __FUNCTION__);
+ printk(KERN_WARNING "%s: kobj create error\n", __func__);
init_rootfs();
init_mount_tree();
}
-void __put_mnt_ns(struct mnt_namespace *ns)
+void put_mnt_ns(struct mnt_namespace *ns)
{
- struct vfsmount *root = ns->root;
LIST_HEAD(umount_list);
- ns->root = NULL;
- spin_unlock(&vfsmount_lock);
+
+ if (!atomic_dec_and_test(&ns->count))
+ return;
down_write(&namespace_sem);
spin_lock(&vfsmount_lock);
- umount_tree(root, 0, &umount_list);
+ umount_tree(ns->root, 0, &umount_list);
spin_unlock(&vfsmount_lock);
up_write(&namespace_sem);
release_mounts(&umount_list);
kfree(ns);
}
+EXPORT_SYMBOL(put_mnt_ns);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff