ext4: Add a uapi header for ext4 userspace APIs

Create a uapi header include/uapi/linux/ext4.h, move the ioctls and
associated data structures to the uapi header, and include it from
fs/ext4/ext4.h.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Link: https://lore.kernel.org/r/680175260970d977d16b5cc7e7606483ec99eb63.1680402881.git.josh@joshtriplett.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

3 files changed, 119 insertions, 90 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index d8ebab595b2a..364719171ba7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7728,6 +7728,7 @@ T:	git git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git
 F:	Documentation/filesystems/ext4/
 F:	fs/ext4/
 F:	include/trace/events/ext4.h
+F:	include/uapi/linux/ext4.h
 
 Extended Verification Module (EVM)
 M:	Mimi Zohar <zohar@linux.ibm.com>
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 271d9661ce82..18cb2680dc39 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -40,6 +40,7 @@
 #ifdef __KERNEL__
 #include <linux/compat.h>
 #endif
+#include <uapi/linux/ext4.h>
 
 #include <linux/fscrypt.h>
 #include <linux/fsverity.h>
@@ -591,17 +592,6 @@ static inline void ext4_check_flag_values(void)
 	CHECK_FLAG_VALUE(RESERVED);
 }
 
-/* Used to pass group descriptor data when online resize is done */
-struct ext4_new_group_input {
-	__u32 group;		/* Group number for this data */
-	__u64 block_bitmap;	/* Absolute block number of block bitmap */
-	__u64 inode_bitmap;	/* Absolute block number of inode bitmap */
-	__u64 inode_table;	/* Absolute block number of inode table start */
-	__u32 blocks_count;	/* Total number of blocks in this group */
-	__u16 reserved_blocks;	/* Number of reserved blocks in this group */
-	__u16 unused;
-};
-
 #if defined(__KERNEL__) && defined(CONFIG_COMPAT)
 struct compat_ext4_new_group_input {
 	u32 group;
@@ -698,70 +688,6 @@ enum {
 #define EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER	0x0020
 #define EXT4_FREE_BLOCKS_RERESERVE_CLUSTER      0x0040
 
-/*
- * ioctl commands
- */
-#define	EXT4_IOC_GETVERSION		_IOR('f', 3, long)
-#define	EXT4_IOC_SETVERSION		_IOW('f', 4, long)
-#define	EXT4_IOC_GETVERSION_OLD		FS_IOC_GETVERSION
-#define	EXT4_IOC_SETVERSION_OLD		FS_IOC_SETVERSION
-#define EXT4_IOC_GETRSVSZ		_IOR('f', 5, long)
-#define EXT4_IOC_SETRSVSZ		_IOW('f', 6, long)
-#define EXT4_IOC_GROUP_EXTEND		_IOW('f', 7, unsigned long)
-#define EXT4_IOC_GROUP_ADD		_IOW('f', 8, struct ext4_new_group_input)
-#define EXT4_IOC_MIGRATE		_IO('f', 9)
- /* note ioctl 10 reserved for an early version of the FIEMAP ioctl */
- /* note ioctl 11 reserved for filesystem-independent FIEMAP ioctl */
-#define EXT4_IOC_ALLOC_DA_BLKS		_IO('f', 12)
-#define EXT4_IOC_MOVE_EXT		_IOWR('f', 15, struct move_extent)
-#define EXT4_IOC_RESIZE_FS		_IOW('f', 16, __u64)
-#define EXT4_IOC_SWAP_BOOT		_IO('f', 17)
-#define EXT4_IOC_PRECACHE_EXTENTS	_IO('f', 18)
-/* ioctl codes 19--39 are reserved for fscrypt */
-#define EXT4_IOC_CLEAR_ES_CACHE		_IO('f', 40)
-#define EXT4_IOC_GETSTATE		_IOW('f', 41, __u32)
-#define EXT4_IOC_GET_ES_CACHE		_IOWR('f', 42, struct fiemap)
-#define EXT4_IOC_CHECKPOINT		_IOW('f', 43, __u32)
-#define EXT4_IOC_GETFSUUID		_IOR('f', 44, struct fsuuid)
-#define EXT4_IOC_SETFSUUID		_IOW('f', 44, struct fsuuid)
-
-#define EXT4_IOC_SHUTDOWN _IOR ('X', 125, __u32)
-
-/*
- * Flags for going down operation
- */
-#define EXT4_GOING_FLAGS_DEFAULT		0x0	/* going down */
-#define EXT4_GOING_FLAGS_LOGFLUSH		0x1	/* flush log but not data */
-#define EXT4_GOING_FLAGS_NOLOGFLUSH		0x2	/* don't flush log nor data */
-
-/*
- * Flags returned by EXT4_IOC_GETSTATE
- *
- * We only expose to userspace a subset of the state flags in
- * i_state_flags
- */
-#define EXT4_STATE_FLAG_EXT_PRECACHED	0x00000001
-#define EXT4_STATE_FLAG_NEW		0x00000002
-#define EXT4_STATE_FLAG_NEWENTRY	0x00000004
-#define EXT4_STATE_FLAG_DA_ALLOC_CLOSE	0x00000008
-
-/* flags for ioctl EXT4_IOC_CHECKPOINT */
-#define EXT4_IOC_CHECKPOINT_FLAG_DISCARD	0x1
-#define EXT4_IOC_CHECKPOINT_FLAG_ZEROOUT	0x2
-#define EXT4_IOC_CHECKPOINT_FLAG_DRY_RUN	0x4
-#define EXT4_IOC_CHECKPOINT_FLAG_VALID		(EXT4_IOC_CHECKPOINT_FLAG_DISCARD | \
-						EXT4_IOC_CHECKPOINT_FLAG_ZEROOUT | \
-						EXT4_IOC_CHECKPOINT_FLAG_DRY_RUN)
-
-/*
- * Structure for EXT4_IOC_GETFSUUID/EXT4_IOC_SETFSUUID
- */
-struct fsuuid {
-	__u32       fsu_len;
-	__u32       fsu_flags;
-	__u8        fsu_uuid[];
-};
-
 #if defined(__KERNEL__) && defined(CONFIG_COMPAT)
 /*
  * ioctl commands in 32 bit emulation
@@ -776,12 +702,6 @@ struct fsuuid {
 #define EXT4_IOC32_SETVERSION_OLD	FS_IOC32_SETVERSION
 #endif
 
-/*
- * Returned by EXT4_IOC_GET_ES_CACHE as an additional possible flag.
- * It indicates that the entry in extent status cache is for a hole.
- */
-#define EXT4_FIEMAP_EXTENT_HOLE		0x08000000
-
 /* Max physical block we can address w/o extents */
 #define EXT4_MAX_BLOCK_FILE_PHYS	0xFFFFFFFF
 
@@ -852,15 +772,6 @@ struct ext4_inode {
 	__le32	i_projid;	/* Project ID */
 };
 
-struct move_extent {
-	__u32 reserved;		/* should be zero */
-	__u32 donor_fd;		/* donor file descriptor */
-	__u64 orig_start;	/* logical start offset in block for orig */
-	__u64 donor_start;	/* logical start offset in block for donor */
-	__u64 len;		/* block length to be moved */
-	__u64 moved_len;	/* moved block length */
-};
-
 #define EXT4_EPOCH_BITS 2
 #define EXT4_EPOCH_MASK ((1 << EXT4_EPOCH_BITS) - 1)
 #define EXT4_NSEC_MASK  (~0UL << EXT4_EPOCH_BITS)
diff --git a/include/uapi/linux/ext4.h b/include/uapi/linux/ext4.h
new file mode 100644
index 000000000000..1c4c2dd29112
--- /dev/null
+++ b/include/uapi/linux/ext4.h
@@ -0,0 +1,117 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+
+#ifndef _UAPI_LINUX_EXT4_H
+#define _UAPI_LINUX_EXT4_H
+#include <linux/fiemap.h>
+#include <linux/fs.h>
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+/*
+ * ext4-specific ioctl commands
+ */
+#define	EXT4_IOC_GETVERSION		_IOR('f', 3, long)
+#define	EXT4_IOC_SETVERSION		_IOW('f', 4, long)
+#define	EXT4_IOC_GETVERSION_OLD		FS_IOC_GETVERSION
+#define	EXT4_IOC_SETVERSION_OLD		FS_IOC_SETVERSION
+#define EXT4_IOC_GETRSVSZ		_IOR('f', 5, long)
+#define EXT4_IOC_SETRSVSZ		_IOW('f', 6, long)
+#define EXT4_IOC_GROUP_EXTEND		_IOW('f', 7, unsigned long)
+#define EXT4_IOC_GROUP_ADD		_IOW('f', 8, struct ext4_new_group_input)
+#define EXT4_IOC_MIGRATE		_IO('f', 9)
+ /* note ioctl 10 reserved for an early version of the FIEMAP ioctl */
+ /* note ioctl 11 reserved for filesystem-independent FIEMAP ioctl */
+#define EXT4_IOC_ALLOC_DA_BLKS		_IO('f', 12)
+#define EXT4_IOC_MOVE_EXT		_IOWR('f', 15, struct move_extent)
+#define EXT4_IOC_RESIZE_FS		_IOW('f', 16, __u64)
+#define EXT4_IOC_SWAP_BOOT		_IO('f', 17)
+#define EXT4_IOC_PRECACHE_EXTENTS	_IO('f', 18)
+/* ioctl codes 19--39 are reserved for fscrypt */
+#define EXT4_IOC_CLEAR_ES_CACHE		_IO('f', 40)
+#define EXT4_IOC_GETSTATE		_IOW('f', 41, __u32)
+#define EXT4_IOC_GET_ES_CACHE		_IOWR('f', 42, struct fiemap)
+#define EXT4_IOC_CHECKPOINT		_IOW('f', 43, __u32)
+#define EXT4_IOC_GETFSUUID		_IOR('f', 44, struct fsuuid)
+#define EXT4_IOC_SETFSUUID		_IOW('f', 44, struct fsuuid)
+
+#define EXT4_IOC_SHUTDOWN _IOR('X', 125, __u32)
+
+/*
+ * ioctl commands in 32 bit emulation
+ */
+#define EXT4_IOC32_GETVERSION		_IOR('f', 3, int)
+#define EXT4_IOC32_SETVERSION		_IOW('f', 4, int)
+#define EXT4_IOC32_GETRSVSZ		_IOR('f', 5, int)
+#define EXT4_IOC32_SETRSVSZ		_IOW('f', 6, int)
+#define EXT4_IOC32_GROUP_EXTEND		_IOW('f', 7, unsigned int)
+#define EXT4_IOC32_GROUP_ADD		_IOW('f', 8, struct compat_ext4_new_group_input)
+#define EXT4_IOC32_GETVERSION_OLD	FS_IOC32_GETVERSION
+#define EXT4_IOC32_SETVERSION_OLD	FS_IOC32_SETVERSION
+
+/*
+ * Flags returned by EXT4_IOC_GETSTATE
+ *
+ * We only expose to userspace a subset of the state flags in
+ * i_state_flags
+ */
+#define EXT4_STATE_FLAG_EXT_PRECACHED	0x00000001
+#define EXT4_STATE_FLAG_NEW		0x00000002
+#define EXT4_STATE_FLAG_NEWENTRY	0x00000004
+#define EXT4_STATE_FLAG_DA_ALLOC_CLOSE	0x00000008
+
+/*
+ * Flags for ioctl EXT4_IOC_CHECKPOINT
+ */
+#define EXT4_IOC_CHECKPOINT_FLAG_DISCARD	0x1
+#define EXT4_IOC_CHECKPOINT_FLAG_ZEROOUT	0x2
+#define EXT4_IOC_CHECKPOINT_FLAG_DRY_RUN	0x4
+#define EXT4_IOC_CHECKPOINT_FLAG_VALID		(EXT4_IOC_CHECKPOINT_FLAG_DISCARD | \
+						EXT4_IOC_CHECKPOINT_FLAG_ZEROOUT | \
+						EXT4_IOC_CHECKPOINT_FLAG_DRY_RUN)
+
+/*
+ * Structure for EXT4_IOC_GETFSUUID/EXT4_IOC_SETFSUUID
+ */
+struct fsuuid {
+	__u32       fsu_len;
+	__u32       fsu_flags;
+	__u8        fsu_uuid[];
+};
+
+/*
+ * Structure for EXT4_IOC_MOVE_EXT
+ */
+struct move_extent {
+	__u32 reserved;		/* should be zero */
+	__u32 donor_fd;		/* donor file descriptor */
+	__u64 orig_start;	/* logical start offset in block for orig */
+	__u64 donor_start;	/* logical start offset in block for donor */
+	__u64 len;		/* block length to be moved */
+	__u64 moved_len;	/* moved block length */
+};
+
+/*
+ * Flags used by EXT4_IOC_SHUTDOWN
+ */
+#define EXT4_GOING_FLAGS_DEFAULT		0x0	/* going down */
+#define EXT4_GOING_FLAGS_LOGFLUSH		0x1	/* flush log but not data */
+#define EXT4_GOING_FLAGS_NOLOGFLUSH		0x2	/* don't flush log nor data */
+
+/* Used to pass group descriptor data when online resize is done */
+struct ext4_new_group_input {
+	__u32 group;		/* Group number for this data */
+	__u64 block_bitmap;	/* Absolute block number of block bitmap */
+	__u64 inode_bitmap;	/* Absolute block number of inode bitmap */
+	__u64 inode_table;	/* Absolute block number of inode table start */
+	__u32 blocks_count;	/* Total number of blocks in this group */
+	__u16 reserved_blocks;	/* Number of reserved blocks in this group */
+	__u16 unused;
+};
+
+/*
+ * Returned by EXT4_IOC_GET_ES_CACHE as an additional possible flag.
+ * It indicates that the entry in extent status cache is for a hole.
+ */
+#define EXT4_FIEMAP_EXTENT_HOLE		0x08000000
+
+#endif /* _UAPI_LINUX_EXT4_H */