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-rw-r--r--fs/super.c27
1 files changed, 27 insertions, 0 deletions
diff --git a/fs/super.c b/fs/super.c
index 8341e4e1d738..5260d620c555 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -107,6 +107,7 @@ out:
static inline void destroy_super(struct super_block *s)
{
security_sb_free(s);
+ kfree(s->s_subtype);
kfree(s);
}
@@ -907,6 +908,29 @@ out:
EXPORT_SYMBOL_GPL(vfs_kern_mount);
+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)
{
@@ -915,6 +939,9 @@ do_kern_mount(const char *fstype, int flags, const char *name, void *data)
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;
}