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vfs: split off vfsmount-related parts of vfs_kern_mount()
new function: mount_fs(). Does all work done by vfs_kern_mount() except the allocation and filling of vfsmount; returns root dentry or ERR_PTR(). vfs_kern_mount() switched to using it and taken to fs/namespace.c, along with its wrappers. alloc_vfsmnt()/free_vfsmnt() made static. functions in namespace.c slightly reordered. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
parent
fbe0aa1f3d
commit
9d412a43c3
@ -12,6 +12,7 @@
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#include <linux/lglock.h>
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struct super_block;
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struct file_system_type;
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struct linux_binprm;
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struct path;
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@ -61,8 +62,6 @@ extern int check_unsafe_exec(struct linux_binprm *);
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extern int copy_mount_options(const void __user *, unsigned long *);
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extern int copy_mount_string(const void __user *, char **);
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extern void free_vfsmnt(struct vfsmount *);
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extern struct vfsmount *alloc_vfsmnt(const char *);
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extern unsigned int mnt_get_count(struct vfsmount *mnt);
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extern struct vfsmount *__lookup_mnt(struct vfsmount *, struct dentry *, int);
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extern void mnt_set_mountpoint(struct vfsmount *, struct dentry *,
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@ -99,6 +98,8 @@ extern struct file *get_empty_filp(void);
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extern int do_remount_sb(struct super_block *, int, void *, int);
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extern void __put_super(struct super_block *sb);
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extern void put_super(struct super_block *sb);
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extern struct dentry *mount_fs(struct file_system_type *,
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int, const char *, void *);
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/*
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* open.c
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153
fs/namespace.c
153
fs/namespace.c
@ -196,7 +196,7 @@ unsigned int mnt_get_count(struct vfsmount *mnt)
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#endif
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}
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struct vfsmount *alloc_vfsmnt(const char *name)
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static struct vfsmount *alloc_vfsmnt(const char *name)
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{
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struct vfsmount *mnt = kmem_cache_zalloc(mnt_cache, GFP_KERNEL);
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if (mnt) {
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@ -466,7 +466,7 @@ static void __mnt_unmake_readonly(struct vfsmount *mnt)
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br_write_unlock(vfsmount_lock);
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}
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void free_vfsmnt(struct vfsmount *mnt)
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static void free_vfsmnt(struct vfsmount *mnt)
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{
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kfree(mnt->mnt_devname);
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mnt_free_id(mnt);
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@ -670,6 +670,36 @@ static struct vfsmount *skip_mnt_tree(struct vfsmount *p)
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return p;
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}
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struct vfsmount *
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vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data)
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{
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struct vfsmount *mnt;
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struct dentry *root;
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if (!type)
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return ERR_PTR(-ENODEV);
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mnt = alloc_vfsmnt(name);
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if (!mnt)
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return ERR_PTR(-ENOMEM);
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if (flags & MS_KERNMOUNT)
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mnt->mnt_flags = MNT_INTERNAL;
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root = mount_fs(type, flags, name, data);
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if (IS_ERR(root)) {
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free_vfsmnt(mnt);
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return ERR_CAST(root);
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}
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mnt->mnt_root = root;
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mnt->mnt_sb = root->d_sb;
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mnt->mnt_mountpoint = mnt->mnt_root;
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mnt->mnt_parent = mnt;
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return mnt;
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}
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EXPORT_SYMBOL_GPL(vfs_kern_mount);
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static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root,
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int flag)
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{
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@ -1905,7 +1935,81 @@ out:
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return err;
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}
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static int do_add_mount(struct vfsmount *, struct path *, int);
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static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype)
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{
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int err;
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const char *subtype = strchr(fstype, '.');
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if (subtype) {
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subtype++;
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err = -EINVAL;
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if (!subtype[0])
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goto err;
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} else
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subtype = "";
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mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL);
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err = -ENOMEM;
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if (!mnt->mnt_sb->s_subtype)
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goto err;
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return mnt;
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err:
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mntput(mnt);
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return ERR_PTR(err);
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}
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struct vfsmount *
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do_kern_mount(const char *fstype, int flags, const char *name, void *data)
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{
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struct file_system_type *type = get_fs_type(fstype);
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struct vfsmount *mnt;
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if (!type)
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return ERR_PTR(-ENODEV);
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mnt = vfs_kern_mount(type, flags, name, data);
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if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) &&
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!mnt->mnt_sb->s_subtype)
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mnt = fs_set_subtype(mnt, fstype);
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put_filesystem(type);
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return mnt;
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}
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EXPORT_SYMBOL_GPL(do_kern_mount);
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/*
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* add a mount into a namespace's mount tree
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*/
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static int do_add_mount(struct vfsmount *newmnt, struct path *path, int mnt_flags)
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{
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int err;
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mnt_flags &= ~(MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL);
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down_write(&namespace_sem);
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/* Something was mounted here while we slept */
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err = follow_down(path, true);
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if (err < 0)
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goto unlock;
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err = -EINVAL;
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if (!(mnt_flags & MNT_SHRINKABLE) && !check_mnt(path->mnt))
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goto unlock;
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/* Refuse the same filesystem on the same mount point */
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err = -EBUSY;
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if (path->mnt->mnt_sb == newmnt->mnt_sb &&
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path->mnt->mnt_root == path->dentry)
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goto unlock;
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err = -EINVAL;
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if (S_ISLNK(newmnt->mnt_root->d_inode->i_mode))
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goto unlock;
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newmnt->mnt_flags = mnt_flags;
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err = graft_tree(newmnt, path);
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unlock:
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up_write(&namespace_sem);
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return err;
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}
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/*
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* create a new mount for userspace and request it to be added into the
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@ -1965,43 +2069,6 @@ fail:
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return err;
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}
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/*
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* add a mount into a namespace's mount tree
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*/
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static int do_add_mount(struct vfsmount *newmnt, struct path *path, int mnt_flags)
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{
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int err;
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mnt_flags &= ~(MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL);
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down_write(&namespace_sem);
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/* Something was mounted here while we slept */
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err = follow_down(path, true);
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if (err < 0)
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goto unlock;
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err = -EINVAL;
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if (!(mnt_flags & MNT_SHRINKABLE) && !check_mnt(path->mnt))
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goto unlock;
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/* Refuse the same filesystem on the same mount point */
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err = -EBUSY;
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if (path->mnt->mnt_sb == newmnt->mnt_sb &&
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path->mnt->mnt_root == path->dentry)
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goto unlock;
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err = -EINVAL;
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if (S_ISLNK(newmnt->mnt_root->d_inode->i_mode))
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goto unlock;
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newmnt->mnt_flags = mnt_flags;
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err = graft_tree(newmnt, path);
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unlock:
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up_write(&namespace_sem);
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return err;
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}
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/**
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* mnt_set_expiry - Put a mount on an expiration list
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* @mnt: The mount to list.
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@ -2660,3 +2727,9 @@ void put_mnt_ns(struct mnt_namespace *ns)
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kfree(ns);
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}
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EXPORT_SYMBOL(put_mnt_ns);
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struct vfsmount *kern_mount_data(struct file_system_type *type, void *data)
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{
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return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data);
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}
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EXPORT_SYMBOL_GPL(kern_mount_data);
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96
fs/super.c
96
fs/super.c
@ -910,29 +910,18 @@ struct dentry *mount_single(struct file_system_type *fs_type,
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}
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EXPORT_SYMBOL(mount_single);
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struct vfsmount *
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vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data)
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struct dentry *
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mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
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{
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struct vfsmount *mnt;
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struct dentry *root;
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struct super_block *sb;
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char *secdata = NULL;
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int error;
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if (!type)
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return ERR_PTR(-ENODEV);
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error = -ENOMEM;
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mnt = alloc_vfsmnt(name);
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if (!mnt)
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goto out;
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if (flags & MS_KERNMOUNT)
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mnt->mnt_flags = MNT_INTERNAL;
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int error = -ENOMEM;
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if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) {
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secdata = alloc_secdata();
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if (!secdata)
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goto out_mnt;
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goto out;
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error = security_sb_copy_data(data, secdata);
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if (error)
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@ -944,13 +933,12 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
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error = PTR_ERR(root);
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goto out_free_secdata;
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}
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mnt->mnt_root = root;
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mnt->mnt_sb = root->d_sb;
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BUG_ON(!mnt->mnt_sb);
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WARN_ON(!mnt->mnt_sb->s_bdi);
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mnt->mnt_sb->s_flags |= MS_BORN;
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sb = root->d_sb;
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BUG_ON(!sb);
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WARN_ON(!sb->s_bdi);
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sb->s_flags |= MS_BORN;
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error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata);
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error = security_sb_kern_mount(sb, flags, secdata);
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if (error)
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goto out_sb;
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@ -961,27 +949,21 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
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* violate this rule. This warning should be either removed or
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* converted to a BUG() in 2.6.34.
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*/
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WARN((mnt->mnt_sb->s_maxbytes < 0), "%s set sb->s_maxbytes to "
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"negative value (%lld)\n", type->name, mnt->mnt_sb->s_maxbytes);
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WARN((sb->s_maxbytes < 0), "%s set sb->s_maxbytes to "
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"negative value (%lld)\n", type->name, sb->s_maxbytes);
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mnt->mnt_mountpoint = mnt->mnt_root;
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mnt->mnt_parent = mnt;
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up_write(&mnt->mnt_sb->s_umount);
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up_write(&sb->s_umount);
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free_secdata(secdata);
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return mnt;
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return root;
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out_sb:
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dput(mnt->mnt_root);
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deactivate_locked_super(mnt->mnt_sb);
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dput(root);
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deactivate_locked_super(sb);
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out_free_secdata:
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free_secdata(secdata);
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out_mnt:
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free_vfsmnt(mnt);
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out:
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return ERR_PTR(error);
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}
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EXPORT_SYMBOL_GPL(vfs_kern_mount);
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/**
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* freeze_super - lock the filesystem and force it into a consistent state
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* @sb: the super to lock
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@ -1071,49 +1053,3 @@ out:
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return 0;
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}
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EXPORT_SYMBOL(thaw_super);
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static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype)
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{
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int err;
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const char *subtype = strchr(fstype, '.');
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if (subtype) {
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subtype++;
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err = -EINVAL;
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if (!subtype[0])
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goto err;
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} else
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subtype = "";
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mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL);
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err = -ENOMEM;
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if (!mnt->mnt_sb->s_subtype)
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goto err;
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return mnt;
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err:
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mntput(mnt);
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return ERR_PTR(err);
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}
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struct vfsmount *
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do_kern_mount(const char *fstype, int flags, const char *name, void *data)
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{
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struct file_system_type *type = get_fs_type(fstype);
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struct vfsmount *mnt;
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if (!type)
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return ERR_PTR(-ENODEV);
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mnt = vfs_kern_mount(type, flags, name, data);
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if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) &&
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!mnt->mnt_sb->s_subtype)
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mnt = fs_set_subtype(mnt, fstype);
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put_filesystem(type);
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return mnt;
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}
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EXPORT_SYMBOL_GPL(do_kern_mount);
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struct vfsmount *kern_mount_data(struct file_system_type *type, void *data)
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{
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return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data);
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}
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EXPORT_SYMBOL_GPL(kern_mount_data);
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