[vpsAdminOS] Hide ZFS from container tools

Author: snajpa

include/sys/fs/zfs.h

@@ -1149,6 +1149,7 @@ typedef struct ddt_histogram {
 #define	ZFS_SHARETAB	"/etc/dfs/sharetab"
 
 #define	ZFS_SUPER_MAGIC	0x2fc12fc1
+#define	ZFS_SHACK_MAGIC	0x13372fc1
 
 /* general zvol path */
 #define	ZVOL_DIR	"/dev"

module/os/linux/zfs/zfs_vfsops.c

@@ -1457,6 +1457,7 @@ zfs_statvfs(struct dentry *dentry, struct kstatfs *statp)
 	zfsvfs_t *zfsvfs = dentry->d_sb->s_fs_info;
 	uint64_t refdbytes, availbytes, usedobjs, availobjs;
 	int err = 0;
+	bool magic_hack = false;
 
 	ZFS_ENTER(zfsvfs);
 
@@ -1504,6 +1505,17 @@ zfs_statvfs(struct dentry *dentry, struct kstatfs *statp)
 	statp->f_type = ZFS_SUPER_MAGIC;
 	statp->f_namelen = MAXNAMELEN - 1;
 
+	if (strcmp(current->comm, "containerd") == 0)
+		magic_hack = true;
+	if (strcmp(current->comm, "dockerd") == 0)
+		magic_hack = true;
+	if (strcmp(current->comm, "lxd") == 0)
+		magic_hack = true;
+	if (magic_hack) {
+		printk(KERN_WARNING "ZFS magic faked to %s\n", current->comm);
+		statp->f_type = ZFS_SHACK_MAGIC;
+	}
+
 	/*
 	 * We have all of 40 characters to stuff a string here.
 	 * Is there anything useful we could/should provide?