Btrfs-progs 4.8, fix build on 32bit, ioctl cleanups

index a7235c00c1a0..d0c06657f0c0 100644
@@ -149,7 +149,7 @@ struct btrfs_ioctl_scrub_args {
 	struct btrfs_scrub_progress progress;	/* out */
 	/* pad to 1k */
 	__u64 unused[(1024-32-sizeof(struct btrfs_scrub_progress))/8];
-};
+} __attribute__((packed));
 BUILD_ASSERT(sizeof(struct btrfs_ioctl_scrub_args) == 1024);
 
 #define BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_ALWAYS	0

@@ -160,7 +160,7 @@ struct btrfs_ioctl_dev_replace_start_params {
 						 * above */
 	__u8 srcdev_name[BTRFS_DEVICE_PATH_NAME_MAX + 1];	/* in */
 	__u8 tgtdev_name[BTRFS_DEVICE_PATH_NAME_MAX + 1];	/* in */
-};
+} __attribute__((packed, aligned (8)));
 BUILD_ASSERT(sizeof(struct btrfs_ioctl_dev_replace_start_params) == 2072);
 
 #define BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED	0

@@ -175,7 +175,7 @@ struct btrfs_ioctl_dev_replace_status_params {
 	__u64 time_stopped;	/* out, seconds since 1-Jan-1970 */
 	__u64 num_write_errors;	/* out */
 	__u64 num_uncorrectable_read_errors;	/* out */
-};
+} __attribute__((packed));
 BUILD_ASSERT(sizeof(struct btrfs_ioctl_dev_replace_status_params) == 48);
 
 #define BTRFS_IOCTL_DEV_REPLACE_CMD_START			0

@@ -556,7 +556,7 @@ BUILD_ASSERT(sizeof(struct btrfs_ioctl_qgroup_create_args) == 16);
 struct btrfs_ioctl_timespec {
 	__u64 sec;
 	__u32 nsec;
-};
+} __attribute__((packed, aligned (8)));
 
 struct btrfs_ioctl_received_subvol_args {
 	char	uuid[BTRFS_UUID_SIZE];	/* in */

@@ -601,7 +601,7 @@ struct btrfs_ioctl_send_args {
 	__u64 parent_root;		/* in */
 	__u64 flags;			/* in */
 	__u64 reserved[4];		/* in */
-};
+} __attribute__((packed));
 /*
  * Size of structure depends on pointer width, was not caught.  Kernel handles
  * pointer width differences transparently

index d0c06657f0c0..6baa51ab1724 100644
@@ -570,6 +570,38 @@ struct btrfs_ioctl_received_subvol_args {
 BUILD_ASSERT(sizeof(struct btrfs_ioctl_received_subvol_args) == 200);
 
 /*
+ * If we have a 32-bit userspace and 64-bit kernel, then the UAPI
+ * structures are incorrect, as the timespec structure from userspace
+ * is 4 bytes too small. We define these alternatives here for backward
+ * compatibility, the kernel understands both values.
+ */
+
+/*
+ * Structure size is different on 32bit and 64bit, has some padding if the
+ * structure is embedded. Packing makes sure the size is same on both, but will
+ * be misaligned on 64bit.
+ *
+ * NOTE: do not use in your code, this is for testing only
+ */
+struct btrfs_ioctl_timespec_32 {
+	__u64 sec;
+	__u32 nsec;
+} __attribute__ ((__packed__));
+
+struct btrfs_ioctl_received_subvol_args_32 {
+	char	uuid[BTRFS_UUID_SIZE];	/* in */
+	__u64	stransid;		/* in */
+	__u64	rtransid;		/* out */
+	struct btrfs_ioctl_timespec_32 stime; /* in */
+	struct btrfs_ioctl_timespec_32 rtime; /* out */
+	__u64	flags;			/* in */
+	__u64	reserved[16];		/* in */
+} __attribute__ ((__packed__));
+BUILD_ASSERT(sizeof(struct btrfs_ioctl_received_subvol_args_32) == 192);
+
+#define BTRFS_IOC_SET_RECEIVED_SUBVOL_32_COMPAT_DEFINED 1
+
+/*
  * Caller doesn't want file data in the send stream, even if the
  * search of clone sources doesn't find an extent. UPDATE_EXTENT
  * commands will be sent instead of WRITE commands.

@@ -723,6 +755,12 @@ static inline char *btrfs_err_str(enum btrfs_err_code err_code)
 					struct btrfs_ioctl_logical_ino_args)
 #define BTRFS_IOC_SET_RECEIVED_SUBVOL _IOWR(BTRFS_IOCTL_MAGIC, 37, \
 				struct btrfs_ioctl_received_subvol_args)
+
+#ifdef BTRFS_IOC_SET_RECEIVED_SUBVOL_32_COMPAT_DEFINED
+#define BTRFS_IOC_SET_RECEIVED_SUBVOL_32 _IOWR(BTRFS_IOCTL_MAGIC, 37, \
+				struct btrfs_ioctl_received_subvol_args_32)
+#endif
+
 #define BTRFS_IOC_SEND _IOW(BTRFS_IOCTL_MAGIC, 38, struct btrfs_ioctl_send_args)
 #define BTRFS_IOC_DEVICES_READY _IOR(BTRFS_IOCTL_MAGIC, 39, \
 				     struct btrfs_ioctl_vol_args)

index 6baa51ab1724..f7233da90637 100644
@@ -635,8 +635,8 @@ struct btrfs_ioctl_send_args {
 	__u64 reserved[4];		/* in */
 } __attribute__((packed));
 /*
- * Size of structure depends on pointer width, was not caught.  Kernel handles
- * pointer width differences transparently
+ * Size of structure depends on pointer width, was not caught in the early
+ * days.  Kernel handles pointer width differences transparently.
  */
 BUILD_ASSERT(sizeof(__u64 *) == 8
 	     ? sizeof(struct btrfs_ioctl_send_args) == 72

@@ -644,6 +644,28 @@ BUILD_ASSERT(sizeof(__u64 *) == 8
 		? sizeof(struct btrfs_ioctl_send_args) == 68
 		: 0));
 
+/*
+ * Different pointer width leads to structure size change. Kernel should accept
+ * both ioctl values (derived from the structures) for backward compatibility.
+ * Size of this structure is same on 32bit and 64bit though.
+ *
+ * NOTE: do not use in your code, this is for testing only
+ */
+struct btrfs_ioctl_send_args_64 {
+	__s64 send_fd;			/* in */
+	__u64 clone_sources_count;	/* in */
+	union {
+		__u64 __user *clone_sources;	/* in */
+		__u64 __clone_sources_alignment;
+	};
+	__u64 parent_root;		/* in */
+	__u64 flags;			/* in */
+	__u64 reserved[4];		/* in */
+} __attribute__((packed));
+BUILD_ASSERT(sizeof(struct btrfs_ioctl_send_args_64) == 72);
+
+#define BTRFS_IOC_SEND_64_COMPAT_DEFINED 1
+
 /* Error codes as returned by the kernel */
 enum btrfs_err_code {
 	notused,

@@ -761,6 +783,11 @@ static inline char *btrfs_err_str(enum btrfs_err_code err_code)
 				struct btrfs_ioctl_received_subvol_args_32)
 #endif
 
+#ifdef BTRFS_IOC_SEND_64_COMPAT_DEFINED
+#define BTRFS_IOC_SEND_64 _IOW(BTRFS_IOCTL_MAGIC, 38, \
+		struct btrfs_ioctl_send_args_64)
+#endif
+
 #define BTRFS_IOC_SEND _IOW(BTRFS_IOCTL_MAGIC, 38, struct btrfs_ioctl_send_args)
 #define BTRFS_IOC_DEVICES_READY _IOR(BTRFS_IOCTL_MAGIC, 39, \
 				     struct btrfs_ioctl_vol_args)

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