From 9d412a43c3b26e1e549319e5eec26f0829f9f74d Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 17 Mar 2011 22:08:28 -0400 Subject: 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 --- fs/namespace.c | 153 ++++++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 113 insertions(+), 40 deletions(-) (limited to 'fs/namespace.c') diff --git a/fs/namespace.c b/fs/namespace.c index a2a01a1..453529f 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -196,7 +196,7 @@ unsigned int mnt_get_count(struct vfsmount *mnt) #endif } -struct vfsmount *alloc_vfsmnt(const char *name) +static struct vfsmount *alloc_vfsmnt(const char *name) { struct vfsmount *mnt = kmem_cache_zalloc(mnt_cache, GFP_KERNEL); if (mnt) { @@ -466,7 +466,7 @@ static void __mnt_unmake_readonly(struct vfsmount *mnt) br_write_unlock(vfsmount_lock); } -void free_vfsmnt(struct vfsmount *mnt) +static void free_vfsmnt(struct vfsmount *mnt) { kfree(mnt->mnt_devname); mnt_free_id(mnt); @@ -670,6 +670,36 @@ static struct vfsmount *skip_mnt_tree(struct vfsmount *p) return p; } +struct vfsmount * +vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data) +{ + struct vfsmount *mnt; + struct dentry *root; + + if (!type) + return ERR_PTR(-ENODEV); + + mnt = alloc_vfsmnt(name); + if (!mnt) + return ERR_PTR(-ENOMEM); + + if (flags & MS_KERNMOUNT) + mnt->mnt_flags = MNT_INTERNAL; + + root = mount_fs(type, flags, name, data); + if (IS_ERR(root)) { + free_vfsmnt(mnt); + return ERR_CAST(root); + } + + mnt->mnt_root = root; + mnt->mnt_sb = root->d_sb; + mnt->mnt_mountpoint = mnt->mnt_root; + mnt->mnt_parent = mnt; + return mnt; +} +EXPORT_SYMBOL_GPL(vfs_kern_mount); + static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root, int flag) { @@ -1905,7 +1935,81 @@ out: return err; } -static int do_add_mount(struct vfsmount *, struct path *, int); +static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype) +{ + int err; + const char *subtype = strchr(fstype, '.'); + if (subtype) { + subtype++; + err = -EINVAL; + if (!subtype[0]) + goto err; + } else + subtype = ""; + + mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL); + err = -ENOMEM; + if (!mnt->mnt_sb->s_subtype) + goto err; + return mnt; + + err: + mntput(mnt); + return ERR_PTR(err); +} + +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 vfsmount *mnt; + if (!type) + return ERR_PTR(-ENODEV); + mnt = vfs_kern_mount(type, flags, name, data); + if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) && + !mnt->mnt_sb->s_subtype) + mnt = fs_set_subtype(mnt, fstype); + put_filesystem(type); + return mnt; +} +EXPORT_SYMBOL_GPL(do_kern_mount); + +/* + * add a mount into a namespace's mount tree + */ +static int do_add_mount(struct vfsmount *newmnt, struct path *path, int mnt_flags) +{ + int err; + + mnt_flags &= ~(MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL); + + down_write(&namespace_sem); + /* Something was mounted here while we slept */ + err = follow_down(path, true); + if (err < 0) + goto unlock; + + err = -EINVAL; + if (!(mnt_flags & MNT_SHRINKABLE) && !check_mnt(path->mnt)) + goto unlock; + + /* Refuse the same filesystem on the same mount point */ + err = -EBUSY; + if (path->mnt->mnt_sb == newmnt->mnt_sb && + path->mnt->mnt_root == path->dentry) + goto unlock; + + err = -EINVAL; + if (S_ISLNK(newmnt->mnt_root->d_inode->i_mode)) + goto unlock; + + newmnt->mnt_flags = mnt_flags; + err = graft_tree(newmnt, path); + +unlock: + up_write(&namespace_sem); + return err; +} /* * create a new mount for userspace and request it to be added into the @@ -1965,43 +2069,6 @@ fail: return err; } -/* - * add a mount into a namespace's mount tree - */ -static int do_add_mount(struct vfsmount *newmnt, struct path *path, int mnt_flags) -{ - int err; - - mnt_flags &= ~(MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL); - - down_write(&namespace_sem); - /* Something was mounted here while we slept */ - err = follow_down(path, true); - if (err < 0) - goto unlock; - - err = -EINVAL; - if (!(mnt_flags & MNT_SHRINKABLE) && !check_mnt(path->mnt)) - goto unlock; - - /* Refuse the same filesystem on the same mount point */ - err = -EBUSY; - if (path->mnt->mnt_sb == newmnt->mnt_sb && - path->mnt->mnt_root == path->dentry) - goto unlock; - - err = -EINVAL; - if (S_ISLNK(newmnt->mnt_root->d_inode->i_mode)) - goto unlock; - - newmnt->mnt_flags = mnt_flags; - err = graft_tree(newmnt, path); - -unlock: - up_write(&namespace_sem); - return err; -} - /** * mnt_set_expiry - Put a mount on an expiration list * @mnt: The mount to list. @@ -2660,3 +2727,9 @@ void put_mnt_ns(struct mnt_namespace *ns) kfree(ns); } EXPORT_SYMBOL(put_mnt_ns); + +struct vfsmount *kern_mount_data(struct file_system_type *type, void *data) +{ + return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data); +} +EXPORT_SYMBOL_GPL(kern_mount_data); -- cgit v1.1