Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
diff --git a/fs/super.c b/fs/super.c
new file mode 100644
index 0000000..3a1b8ca
--- /dev/null
+++ b/fs/super.c
@@ -0,0 +1,860 @@
+/*
+ * linux/fs/super.c
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ * super.c contains code to handle: - mount structures
+ * - super-block tables
+ * - filesystem drivers list
+ * - mount system call
+ * - umount system call
+ * - ustat system call
+ *
+ * GK 2/5/95 - Changed to support mounting the root fs via NFS
+ *
+ * Added kerneld support: Jacques Gelinas and Bjorn Ekwall
+ * Added change_root: Werner Almesberger & Hans Lermen, Feb '96
+ * Added options to /proc/mounts:
+ * Torbjörn Lindh (torbjorn.lindh@gopta.se), April 14, 1996.
+ * Added devfs support: Richard Gooch <rgooch@atnf.csiro.au>, 13-JAN-1998
+ * Heavily rewritten for 'one fs - one tree' dcache architecture. AV, Mar 2000
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/smp_lock.h>
+#include <linux/acct.h>
+#include <linux/blkdev.h>
+#include <linux/quotaops.h>
+#include <linux/namei.h>
+#include <linux/buffer_head.h> /* for fsync_super() */
+#include <linux/mount.h>
+#include <linux/security.h>
+#include <linux/syscalls.h>
+#include <linux/vfs.h>
+#include <linux/writeback.h> /* for the emergency remount stuff */
+#include <linux/idr.h>
+#include <linux/kobject.h>
+#include <asm/uaccess.h>
+
+
+void get_filesystem(struct file_system_type *fs);
+void put_filesystem(struct file_system_type *fs);
+struct file_system_type *get_fs_type(const char *name);
+
+LIST_HEAD(super_blocks);
+DEFINE_SPINLOCK(sb_lock);
+
+/**
+ * alloc_super - create new superblock
+ *
+ * Allocates and initializes a new &struct super_block. alloc_super()
+ * returns a pointer new superblock or %NULL if allocation had failed.
+ */
+static struct super_block *alloc_super(void)
+{
+ struct super_block *s = kmalloc(sizeof(struct super_block), GFP_USER);
+ static struct super_operations default_op;
+
+ if (s) {
+ memset(s, 0, sizeof(struct super_block));
+ if (security_sb_alloc(s)) {
+ kfree(s);
+ s = NULL;
+ goto out;
+ }
+ INIT_LIST_HEAD(&s->s_dirty);
+ INIT_LIST_HEAD(&s->s_io);
+ INIT_LIST_HEAD(&s->s_files);
+ INIT_LIST_HEAD(&s->s_instances);
+ INIT_HLIST_HEAD(&s->s_anon);
+ INIT_LIST_HEAD(&s->s_inodes);
+ init_rwsem(&s->s_umount);
+ sema_init(&s->s_lock, 1);
+ down_write(&s->s_umount);
+ s->s_count = S_BIAS;
+ atomic_set(&s->s_active, 1);
+ sema_init(&s->s_vfs_rename_sem,1);
+ sema_init(&s->s_dquot.dqio_sem, 1);
+ sema_init(&s->s_dquot.dqonoff_sem, 1);
+ init_rwsem(&s->s_dquot.dqptr_sem);
+ init_waitqueue_head(&s->s_wait_unfrozen);
+ s->s_maxbytes = MAX_NON_LFS;
+ s->dq_op = sb_dquot_ops;
+ s->s_qcop = sb_quotactl_ops;
+ s->s_op = &default_op;
+ s->s_time_gran = 1000000000;
+ }
+out:
+ return s;
+}
+
+/**
+ * destroy_super - frees a superblock
+ * @s: superblock to free
+ *
+ * Frees a superblock.
+ */
+static inline void destroy_super(struct super_block *s)
+{
+ security_sb_free(s);
+ kfree(s);
+}
+
+/* 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;
+}
+
+/*
+ * Drop a superblock's refcount.
+ * Returns non-zero if the superblock is about to be destroyed and
+ * at least is already removed from super_blocks list, so if we are
+ * making a loop through super blocks then we need to restart.
+ * The caller must hold sb_lock.
+ */
+int __put_super_and_need_restart(struct super_block *sb)
+{
+ /* check for race with generic_shutdown_super() */
+ if (list_empty(&sb->s_list)) {
+ /* super block is removed, need to restart... */
+ __put_super(sb);
+ return 1;
+ }
+ /* can't be the last, since s_list is still in use */
+ sb->s_count--;
+ BUG_ON(sb->s_count == 0);
+ return 0;
+}
+
+/**
+ * put_super - drop a temporary reference to superblock
+ * @sb: superblock in question
+ *
+ * Drops a temporary reference, frees superblock if there's no
+ * references left.
+ */
+static void put_super(struct super_block *sb)
+{
+ spin_lock(&sb_lock);
+ __put_super(sb);
+ spin_unlock(&sb_lock);
+}
+
+
+/**
+ * deactivate_super - drop an active reference to superblock
+ * @s: superblock to deactivate
+ *
+ * Drops an active reference to superblock, acquiring a temprory one if
+ * there is no active references left. In that case we lock superblock,
+ * tell fs driver to shut it down and drop the temporary reference we
+ * had just acquired.
+ */
+void deactivate_super(struct super_block *s)
+{
+ struct file_system_type *fs = s->s_type;
+ if (atomic_dec_and_lock(&s->s_active, &sb_lock)) {
+ s->s_count -= S_BIAS-1;
+ spin_unlock(&sb_lock);
+ down_write(&s->s_umount);
+ fs->kill_sb(s);
+ put_filesystem(fs);
+ put_super(s);
+ }
+}
+
+EXPORT_SYMBOL(deactivate_super);
+
+/**
+ * grab_super - acquire an active reference
+ * @s: reference we are trying to make active
+ *
+ * Tries to acquire an active reference. grab_super() is used when we
+ * had just found a superblock in super_blocks or fs_type->fs_supers
+ * and want to turn it into a full-blown active reference. grab_super()
+ * is called with sb_lock held and drops it. Returns 1 in case of
+ * success, 0 if we had failed (superblock contents was already dead or
+ * dying when grab_super() had been called).
+ */
+static int grab_super(struct super_block *s)
+{
+ s->s_count++;
+ spin_unlock(&sb_lock);
+ down_write(&s->s_umount);
+ if (s->s_root) {
+ spin_lock(&sb_lock);
+ if (s->s_count > S_BIAS) {
+ atomic_inc(&s->s_active);
+ s->s_count--;
+ spin_unlock(&sb_lock);
+ return 1;
+ }
+ spin_unlock(&sb_lock);
+ }
+ up_write(&s->s_umount);
+ put_super(s);
+ yield();
+ return 0;
+}
+
+/**
+ * generic_shutdown_super - common helper for ->kill_sb()
+ * @sb: superblock to kill
+ *
+ * generic_shutdown_super() does all fs-independent work on superblock
+ * shutdown. Typical ->kill_sb() should pick all fs-specific objects
+ * that need destruction out of superblock, call generic_shutdown_super()
+ * and release aforementioned objects. Note: dentries and inodes _are_
+ * taken care of and do not need specific handling.
+ */
+void generic_shutdown_super(struct super_block *sb)
+{
+ struct dentry *root = sb->s_root;
+ struct super_operations *sop = sb->s_op;
+
+ if (root) {
+ sb->s_root = NULL;
+ shrink_dcache_parent(root);
+ shrink_dcache_anon(&sb->s_anon);
+ dput(root);
+ fsync_super(sb);
+ lock_super(sb);
+ sb->s_flags &= ~MS_ACTIVE;
+ /* bad name - it should be evict_inodes() */
+ invalidate_inodes(sb);
+ lock_kernel();
+
+ if (sop->write_super && sb->s_dirt)
+ sop->write_super(sb);
+ if (sop->put_super)
+ sop->put_super(sb);
+
+ /* Forget any remaining inodes */
+ if (invalidate_inodes(sb)) {
+ printk("VFS: Busy inodes after unmount. "
+ "Self-destruct in 5 seconds. Have a nice day...\n");
+ }
+
+ unlock_kernel();
+ unlock_super(sb);
+ }
+ spin_lock(&sb_lock);
+ /* should be initialized for __put_super_and_need_restart() */
+ list_del_init(&sb->s_list);
+ list_del(&sb->s_instances);
+ spin_unlock(&sb_lock);
+ up_write(&sb->s_umount);
+}
+
+EXPORT_SYMBOL(generic_shutdown_super);
+
+/**
+ * sget - find or create a superblock
+ * @type: filesystem type superblock should belong to
+ * @test: comparison callback
+ * @set: setup callback
+ * @data: argument to each of them
+ */
+struct super_block *sget(struct file_system_type *type,
+ int (*test)(struct super_block *,void *),
+ int (*set)(struct super_block *,void *),
+ void *data)
+{
+ struct super_block *s = NULL;
+ struct list_head *p;
+ int err;
+
+retry:
+ spin_lock(&sb_lock);
+ if (test) list_for_each(p, &type->fs_supers) {
+ struct super_block *old;
+ old = list_entry(p, struct super_block, s_instances);
+ if (!test(old, data))
+ continue;
+ if (!grab_super(old))
+ goto retry;
+ if (s)
+ destroy_super(s);
+ return old;
+ }
+ if (!s) {
+ spin_unlock(&sb_lock);
+ s = alloc_super();
+ if (!s)
+ return ERR_PTR(-ENOMEM);
+ goto retry;
+ }
+
+ err = set(s, data);
+ if (err) {
+ spin_unlock(&sb_lock);
+ destroy_super(s);
+ return ERR_PTR(err);
+ }
+ s->s_type = type;
+ strlcpy(s->s_id, type->name, sizeof(s->s_id));
+ list_add_tail(&s->s_list, &super_blocks);
+ list_add(&s->s_instances, &type->fs_supers);
+ spin_unlock(&sb_lock);
+ get_filesystem(type);
+ return s;
+}
+
+EXPORT_SYMBOL(sget);
+
+void drop_super(struct super_block *sb)
+{
+ up_read(&sb->s_umount);
+ put_super(sb);
+}
+
+EXPORT_SYMBOL(drop_super);
+
+static inline void write_super(struct super_block *sb)
+{
+ lock_super(sb);
+ if (sb->s_root && sb->s_dirt)
+ if (sb->s_op->write_super)
+ sb->s_op->write_super(sb);
+ unlock_super(sb);
+}
+
+/*
+ * Note: check the dirty flag before waiting, so we don't
+ * hold up the sync while mounting a device. (The newly
+ * mounted device won't need syncing.)
+ */
+void sync_supers(void)
+{
+ struct super_block * sb;
+restart:
+ spin_lock(&sb_lock);
+ sb = sb_entry(super_blocks.next);
+ while (sb != sb_entry(&super_blocks))
+ if (sb->s_dirt) {
+ sb->s_count++;
+ spin_unlock(&sb_lock);
+ down_read(&sb->s_umount);
+ write_super(sb);
+ drop_super(sb);
+ goto restart;
+ } else
+ sb = sb_entry(sb->s_list.next);
+ spin_unlock(&sb_lock);
+}
+
+/*
+ * Call the ->sync_fs super_op against all filesytems which are r/w and
+ * which implement it.
+ *
+ * This operation is careful to avoid the livelock which could easily happen
+ * if two or more filesystems are being continuously dirtied. s_need_sync_fs
+ * is used only here. We set it against all filesystems and then clear it as
+ * we sync them. So redirtied filesystems are skipped.
+ *
+ * But if process A is currently running sync_filesytems and then process B
+ * calls sync_filesystems as well, process B will set all the s_need_sync_fs
+ * flags again, which will cause process A to resync everything. Fix that with
+ * a local mutex.
+ *
+ * (Fabian) Avoid sync_fs with clean fs & wait mode 0
+ */
+void sync_filesystems(int wait)
+{
+ struct super_block *sb;
+ static DECLARE_MUTEX(mutex);
+
+ down(&mutex); /* Could be down_interruptible */
+ spin_lock(&sb_lock);
+ for (sb = sb_entry(super_blocks.next); sb != sb_entry(&super_blocks);
+ sb = sb_entry(sb->s_list.next)) {
+ if (!sb->s_op->sync_fs)
+ continue;
+ if (sb->s_flags & MS_RDONLY)
+ continue;
+ sb->s_need_sync_fs = 1;
+ }
+ spin_unlock(&sb_lock);
+
+restart:
+ spin_lock(&sb_lock);
+ for (sb = sb_entry(super_blocks.next); sb != sb_entry(&super_blocks);
+ sb = sb_entry(sb->s_list.next)) {
+ if (!sb->s_need_sync_fs)
+ continue;
+ sb->s_need_sync_fs = 0;
+ if (sb->s_flags & MS_RDONLY)
+ continue; /* hm. Was remounted r/o meanwhile */
+ sb->s_count++;
+ spin_unlock(&sb_lock);
+ down_read(&sb->s_umount);
+ if (sb->s_root && (wait || sb->s_dirt))
+ sb->s_op->sync_fs(sb, wait);
+ drop_super(sb);
+ goto restart;
+ }
+ spin_unlock(&sb_lock);
+ up(&mutex);
+}
+
+/**
+ * get_super - get the superblock of a device
+ * @bdev: device to get the superblock for
+ *
+ * Scans the superblock list and finds the superblock of the file system
+ * mounted on the device given. %NULL is returned if no match is found.
+ */
+
+struct super_block * get_super(struct block_device *bdev)
+{
+ struct list_head *p;
+ if (!bdev)
+ return NULL;
+rescan:
+ spin_lock(&sb_lock);
+ list_for_each(p, &super_blocks) {
+ struct super_block *s = sb_entry(p);
+ if (s->s_bdev == bdev) {
+ s->s_count++;
+ spin_unlock(&sb_lock);
+ down_read(&s->s_umount);
+ if (s->s_root)
+ return s;
+ drop_super(s);
+ goto rescan;
+ }
+ }
+ spin_unlock(&sb_lock);
+ return NULL;
+}
+
+EXPORT_SYMBOL(get_super);
+
+struct super_block * user_get_super(dev_t dev)
+{
+ struct list_head *p;
+
+rescan:
+ spin_lock(&sb_lock);
+ list_for_each(p, &super_blocks) {
+ struct super_block *s = sb_entry(p);
+ if (s->s_dev == dev) {
+ s->s_count++;
+ spin_unlock(&sb_lock);
+ down_read(&s->s_umount);
+ if (s->s_root)
+ return s;
+ drop_super(s);
+ goto rescan;
+ }
+ }
+ spin_unlock(&sb_lock);
+ return NULL;
+}
+
+EXPORT_SYMBOL(user_get_super);
+
+asmlinkage long sys_ustat(unsigned dev, struct ustat __user * ubuf)
+{
+ struct super_block *s;
+ struct ustat tmp;
+ struct kstatfs sbuf;
+ int err = -EINVAL;
+
+ s = user_get_super(new_decode_dev(dev));
+ if (s == NULL)
+ goto out;
+ err = vfs_statfs(s, &sbuf);
+ drop_super(s);
+ if (err)
+ goto out;
+
+ memset(&tmp,0,sizeof(struct ustat));
+ tmp.f_tfree = sbuf.f_bfree;
+ tmp.f_tinode = sbuf.f_ffree;
+
+ err = copy_to_user(ubuf,&tmp,sizeof(struct ustat)) ? -EFAULT : 0;
+out:
+ return err;
+}
+
+/**
+ * mark_files_ro
+ * @sb: superblock in question
+ *
+ * All files are marked read/only. We don't care about pending
+ * delete files so this should be used in 'force' mode only
+ */
+
+static void mark_files_ro(struct super_block *sb)
+{
+ struct file *f;
+
+ file_list_lock();
+ list_for_each_entry(f, &sb->s_files, f_list) {
+ if (S_ISREG(f->f_dentry->d_inode->i_mode) && file_count(f))
+ f->f_mode &= ~FMODE_WRITE;
+ }
+ file_list_unlock();
+}
+
+/**
+ * do_remount_sb - asks filesystem to change mount options.
+ * @sb: superblock in question
+ * @flags: numeric part of options
+ * @data: the rest of options
+ * @force: whether or not to force the change
+ *
+ * Alters the mount options of a mounted file system.
+ */
+int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
+{
+ int retval;
+
+ if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev))
+ return -EACCES;
+ if (flags & MS_RDONLY)
+ acct_auto_close(sb);
+ shrink_dcache_sb(sb);
+ fsync_super(sb);
+
+ /* If we are remounting RDONLY and current sb is read/write,
+ make sure there are no rw files opened */
+ if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY)) {
+ if (force)
+ mark_files_ro(sb);
+ else if (!fs_may_remount_ro(sb))
+ return -EBUSY;
+ }
+
+ if (sb->s_op->remount_fs) {
+ lock_super(sb);
+ retval = sb->s_op->remount_fs(sb, &flags, data);
+ unlock_super(sb);
+ if (retval)
+ return retval;
+ }
+ sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
+ return 0;
+}
+
+static void do_emergency_remount(unsigned long foo)
+{
+ struct super_block *sb;
+
+ spin_lock(&sb_lock);
+ list_for_each_entry(sb, &super_blocks, s_list) {
+ sb->s_count++;
+ spin_unlock(&sb_lock);
+ down_read(&sb->s_umount);
+ if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) {
+ /*
+ * ->remount_fs needs lock_kernel().
+ *
+ * What lock protects sb->s_flags??
+ */
+ lock_kernel();
+ do_remount_sb(sb, MS_RDONLY, NULL, 1);
+ unlock_kernel();
+ }
+ drop_super(sb);
+ spin_lock(&sb_lock);
+ }
+ spin_unlock(&sb_lock);
+ printk("Emergency Remount complete\n");
+}
+
+void emergency_remount(void)
+{
+ pdflush_operation(do_emergency_remount, 0);
+}
+
+/*
+ * Unnamed block devices are dummy devices used by virtual
+ * filesystems which don't use real block-devices. -- jrs
+ */
+
+static struct idr unnamed_dev_idr;
+static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */
+
+int set_anon_super(struct super_block *s, void *data)
+{
+ int dev;
+ int error;
+
+ retry:
+ if (idr_pre_get(&unnamed_dev_idr, GFP_ATOMIC) == 0)
+ return -ENOMEM;
+ 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);
+ idr_remove(&unnamed_dev_idr, dev);
+ spin_unlock(&unnamed_dev_lock);
+ return -EMFILE;
+ }
+ s->s_dev = MKDEV(0, dev & MINORMASK);
+ return 0;
+}
+
+EXPORT_SYMBOL(set_anon_super);
+
+void kill_anon_super(struct super_block *sb)
+{
+ int slot = MINOR(sb->s_dev);
+
+ generic_shutdown_super(sb);
+ spin_lock(&unnamed_dev_lock);
+ idr_remove(&unnamed_dev_idr, slot);
+ spin_unlock(&unnamed_dev_lock);
+}
+
+EXPORT_SYMBOL(kill_anon_super);
+
+void __init unnamed_dev_init(void)
+{
+ idr_init(&unnamed_dev_idr);
+}
+
+void kill_litter_super(struct super_block *sb)
+{
+ if (sb->s_root)
+ d_genocide(sb->s_root);
+ kill_anon_super(sb);
+}
+
+EXPORT_SYMBOL(kill_litter_super);
+
+static int set_bdev_super(struct super_block *s, void *data)
+{
+ s->s_bdev = data;
+ s->s_dev = s->s_bdev->bd_dev;
+ return 0;
+}
+
+static int test_bdev_super(struct super_block *s, void *data)
+{
+ return (void *)s->s_bdev == data;
+}
+
+static void bdev_uevent(struct block_device *bdev, enum kobject_action action)
+{
+ if (bdev->bd_disk) {
+ if (bdev->bd_part)
+ kobject_uevent(&bdev->bd_part->kobj, action, NULL);
+ else
+ kobject_uevent(&bdev->bd_disk->kobj, action, NULL);
+ }
+}
+
+struct super_block *get_sb_bdev(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *data,
+ int (*fill_super)(struct super_block *, void *, int))
+{
+ struct block_device *bdev;
+ struct super_block *s;
+ int error = 0;
+
+ bdev = open_bdev_excl(dev_name, flags, fs_type);
+ if (IS_ERR(bdev))
+ return (struct super_block *)bdev;
+
+ /*
+ * once the super is inserted into the list by sget, s_umount
+ * will protect the lockfs code from trying to start a snapshot
+ * while we are mounting
+ */
+ down(&bdev->bd_mount_sem);
+ s = sget(fs_type, test_bdev_super, set_bdev_super, bdev);
+ up(&bdev->bd_mount_sem);
+ if (IS_ERR(s))
+ goto out;
+
+ if (s->s_root) {
+ if ((flags ^ s->s_flags) & MS_RDONLY) {
+ up_write(&s->s_umount);
+ deactivate_super(s);
+ s = ERR_PTR(-EBUSY);
+ }
+ goto out;
+ } else {
+ char b[BDEVNAME_SIZE];
+
+ s->s_flags = flags;
+ strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
+ s->s_old_blocksize = block_size(bdev);
+ sb_set_blocksize(s, s->s_old_blocksize);
+ error = fill_super(s, data, flags & MS_VERBOSE ? 1 : 0);
+ if (error) {
+ up_write(&s->s_umount);
+ deactivate_super(s);
+ s = ERR_PTR(error);
+ } else {
+ s->s_flags |= MS_ACTIVE;
+ bdev_uevent(bdev, KOBJ_MOUNT);
+ }
+ }
+
+ return s;
+
+out:
+ close_bdev_excl(bdev);
+ return s;
+}
+
+EXPORT_SYMBOL(get_sb_bdev);
+
+void kill_block_super(struct super_block *sb)
+{
+ struct block_device *bdev = sb->s_bdev;
+
+ bdev_uevent(bdev, KOBJ_UMOUNT);
+ generic_shutdown_super(sb);
+ sync_blockdev(bdev);
+ close_bdev_excl(bdev);
+}
+
+EXPORT_SYMBOL(kill_block_super);
+
+struct super_block *get_sb_nodev(struct file_system_type *fs_type,
+ int flags, void *data,
+ int (*fill_super)(struct super_block *, void *, int))
+{
+ int error;
+ struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL);
+
+ if (IS_ERR(s))
+ return s;
+
+ s->s_flags = flags;
+
+ error = fill_super(s, data, flags & MS_VERBOSE ? 1 : 0);
+ if (error) {
+ up_write(&s->s_umount);
+ deactivate_super(s);
+ return ERR_PTR(error);
+ }
+ s->s_flags |= MS_ACTIVE;
+ return s;
+}
+
+EXPORT_SYMBOL(get_sb_nodev);
+
+static int compare_single(struct super_block *s, void *p)
+{
+ return 1;
+}
+
+struct super_block *get_sb_single(struct file_system_type *fs_type,
+ int flags, void *data,
+ int (*fill_super)(struct super_block *, void *, int))
+{
+ struct super_block *s;
+ int error;
+
+ s = sget(fs_type, compare_single, set_anon_super, NULL);
+ if (IS_ERR(s))
+ return s;
+ if (!s->s_root) {
+ s->s_flags = flags;
+ error = fill_super(s, data, flags & MS_VERBOSE ? 1 : 0);
+ if (error) {
+ up_write(&s->s_umount);
+ deactivate_super(s);
+ return ERR_PTR(error);
+ }
+ s->s_flags |= MS_ACTIVE;
+ }
+ do_remount_sb(s, flags, data, 0);
+ return s;
+}
+
+EXPORT_SYMBOL(get_sb_single);
+
+struct vfsmount *
+do_kern_mount(const char *fstype, int flags, const char *name, void *data)
+{
+ struct file_system_type *type = get_fs_type(fstype);
+ struct super_block *sb = ERR_PTR(-ENOMEM);
+ struct vfsmount *mnt;
+ int error;
+ char *secdata = NULL;
+
+ if (!type)
+ return ERR_PTR(-ENODEV);
+
+ mnt = alloc_vfsmnt(name);
+ if (!mnt)
+ goto out;
+
+ if (data) {
+ secdata = alloc_secdata();
+ if (!secdata) {
+ sb = ERR_PTR(-ENOMEM);
+ goto out_mnt;
+ }
+
+ error = security_sb_copy_data(type, data, secdata);
+ if (error) {
+ sb = ERR_PTR(error);
+ goto out_free_secdata;
+ }
+ }
+
+ sb = type->get_sb(type, flags, name, data);
+ if (IS_ERR(sb))
+ goto out_free_secdata;
+ error = security_sb_kern_mount(sb, secdata);
+ if (error)
+ goto out_sb;
+ mnt->mnt_sb = 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;
+out_sb:
+ up_write(&sb->s_umount);
+ deactivate_super(sb);
+ sb = ERR_PTR(error);
+out_free_secdata:
+ free_secdata(secdata);
+out_mnt:
+ free_vfsmnt(mnt);
+out:
+ put_filesystem(type);
+ 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);
+}
+
+EXPORT_SYMBOL(kern_mount);