#include <linux/vfs.h>
#include <linux/writeback.h> /* for the emergency remount stuff */
#include <linux/idr.h>
+#include <linux/devpts_fs.h>
+#include <linux/proc_fs.h>
#include <asm/uaccess.h>
/* Superblock refcounting */
+/*
+ * Drop a superblock's refcount. Returns non-zero if the superblock was
+ * destroyed. The caller must hold sb_lock.
+ */
+int __put_super(struct super_block *sb)
+{
+ int ret = 0;
+
+ if (!--sb->s_count) {
+ destroy_super(sb);
+ ret = 1;
+ }
+ return ret;
+}
+
/**
* put_super - drop a temporary reference to superblock
* @s: superblock in question
* Drops a temporary reference, frees superblock if there's no
* references left.
*/
-static inline void put_super(struct super_block *s)
+static void put_super(struct super_block *sb)
{
spin_lock(&sb_lock);
- if (!--s->s_count)
- destroy_super(s);
+ __put_super(sb);
spin_unlock(&sb_lock);
}
+
/**
* deactivate_super - drop an active reference to superblock
* @s: superblock to deactivate
return ERR_PTR(err);
}
s->s_type = type;
+ strlcpy(s->s_id, type->name, sizeof(s->s_id));
list_add(&s->s_list, super_blocks.prev);
list_add(&s->s_instances, &type->fs_supers);
spin_unlock(&sb_lock);
int set_anon_super(struct super_block *s, void *data)
{
int dev;
+ int error;
- spin_lock(&unnamed_dev_lock);
- if (idr_pre_get(&unnamed_dev_idr, GFP_ATOMIC) == 0) {
- spin_unlock(&unnamed_dev_lock);
+ retry:
+ if (idr_pre_get(&unnamed_dev_idr, GFP_ATOMIC) == 0)
return -ENOMEM;
- }
- dev = idr_get_new(&unnamed_dev_idr, NULL);
+ spin_lock(&unnamed_dev_lock);
+ error = idr_get_new(&unnamed_dev_idr, NULL, &dev);
spin_unlock(&unnamed_dev_lock);
+ if (error == -EAGAIN)
+ /* We raced and lost with another CPU. */
+ goto retry;
+ else if (error)
+ return -EAGAIN;
if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) {
spin_lock(&unnamed_dev_lock);
sb = type->get_sb(type, flags, name, data);
if (IS_ERR(sb))
goto out_free_secdata;
+
+ error = -EPERM;
+ if (!capable(CAP_SYS_ADMIN) && !sb->s_bdev &&
+ (sb->s_magic != PROC_SUPER_MAGIC) &&
+ (sb->s_magic != DEVPTS_SUPER_MAGIC))
+ goto out_sb;
+
error = security_sb_kern_mount(sb, secdata);
if (error)
goto out_sb;
mnt->mnt_root = dget(sb->s_root);
mnt->mnt_mountpoint = sb->s_root;
mnt->mnt_parent = mnt;
+ mnt->mnt_namespace = current->namespace;
up_write(&sb->s_umount);
put_filesystem(type);
return mnt;
return (struct vfsmount *)sb;
}
+EXPORT_SYMBOL_GPL(do_kern_mount);
+
struct vfsmount *kern_mount(struct file_system_type *type)
{
return do_kern_mount(type->name, 0, type->name, NULL);