teach vfs_get_tree() to handle subtype, switch do_new_mount() to it
Roll the handling of subtypes into do_new_mount() and vfs_get_tree(). The
former determines any subtype string and hangs it off the fs_context; the
latter applies it.
Make do_new_mount() create, parameterise and commit an fs_context and
create a mount for itself rather than calling vfs_kern_mount().
[AV -- missing kstrdup()]
[AV -- ... and no kstrdup() if we get to setting ->s_submount - we
simply transfer it from fc, leaving NULL behind]
[AV -- constify ->s_submount, while we are at it]
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/namespace.c b/fs/namespace.c
index 156771f..0354cb6 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2479,29 +2479,6 @@ static int do_move_mount(struct path *path, const char *old_name)
return err;
}
-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);
-}
-
/*
* add a mount into a namespace's mount tree
*/
@@ -2557,7 +2534,9 @@ static int do_new_mount(struct path *path, const char *fstype, int sb_flags,
{
struct file_system_type *type;
struct vfsmount *mnt;
- int err;
+ struct fs_context *fc;
+ const char *subtype = NULL;
+ int err = 0;
if (!fstype)
return -EINVAL;
@@ -2566,23 +2545,59 @@ static int do_new_mount(struct path *path, const char *fstype, int sb_flags,
if (!type)
return -ENODEV;
- mnt = vfs_kern_mount(type, sb_flags, name, data);
- if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) &&
- !mnt->mnt_sb->s_subtype)
- mnt = fs_set_subtype(mnt, fstype);
+ if (type->fs_flags & FS_HAS_SUBTYPE) {
+ subtype = strchr(fstype, '.');
+ if (subtype) {
+ subtype++;
+ if (!*subtype) {
+ put_filesystem(type);
+ return -EINVAL;
+ }
+ } else {
+ subtype = "";
+ }
+ }
+ fc = fs_context_for_mount(type, sb_flags);
put_filesystem(type);
- if (IS_ERR(mnt))
- return PTR_ERR(mnt);
+ if (IS_ERR(fc))
+ return PTR_ERR(fc);
+
+ if (subtype) {
+ fc->subtype = kstrdup(subtype, GFP_KERNEL);
+ if (!fc->subtype)
+ err = -ENOMEM;
+ }
+ if (!err && name) {
+ fc->source = kstrdup(name, GFP_KERNEL);
+ if (!fc->source)
+ err = -ENOMEM;
+ }
+ if (!err)
+ err = parse_monolithic_mount_data(fc, data);
+ if (!err)
+ err = vfs_get_tree(fc);
+ if (err)
+ goto out;
+
+ up_write(&fc->root->d_sb->s_umount);
+ mnt = vfs_create_mount(fc);
+ if (IS_ERR(mnt)) {
+ err = PTR_ERR(mnt);
+ goto out;
+ }
if (mount_too_revealing(mnt, &mnt_flags)) {
mntput(mnt);
- return -EPERM;
+ err = -EPERM;
+ goto out;
}
err = do_add_mount(real_mount(mnt), path, mnt_flags);
if (err)
mntput(mnt);
+out:
+ put_fs_context(fc);
return err;
}
diff --git a/fs/super.c b/fs/super.c
index fc38872..b91b6df 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1262,6 +1262,11 @@ int vfs_get_tree(struct fs_context *fc)
sb = fc->root->d_sb;
WARN_ON(!sb->s_bdi);
+ if (fc->subtype && !sb->s_subtype) {
+ sb->s_subtype = fc->subtype;
+ fc->subtype = NULL;
+ }
+
/*
* Write barrier is for super_cache_count(). We place it before setting
* SB_BORN as the data dependency between the two functions is the
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 811c777..36fff12 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1447,7 +1447,7 @@ struct super_block {
* Filesystem subtype. If non-empty the filesystem type field
* in /proc/mounts will be "type.subtype"
*/
- char *s_subtype;
+ const char *s_subtype;
const struct dentry_operations *s_d_op; /* default d_op for dentries */
