Merge branch 'work.copy_file_range' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs copy_file_range updates from Al Viro:
"Several series around copy_file_range/CLONE"

* 'work.copy_file_range' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
btrfs: use new dedupe data function pointer
vfs: hoist the btrfs deduplication ioctl to the vfs
vfs: wire up compat ioctl for CLONE/CLONE_RANGE
cifs: avoid unused variable and label
nfsd: implement the NFSv4.2 CLONE operation
nfsd: Pass filehandle to nfs4_preprocess_stateid_op()
vfs: pull btrfs clone API to vfs layer
locks: new locks_mandatory_area calling convention
vfs: Add vfs_copy_file_range() support for pagecache copies
btrfs: add .copy_file_range file operation
x86: add sys_copy_file_range to syscall tables
vfs: add copy_file_range syscall and vfs helper

arch/x86/entry/syscalls/syscall_32.tbl

···
 374	i386	userfaultfd		sys_userfaultfd
 375	i386	membarrier		sys_membarrier
 376	i386	mlock2			sys_mlock2
+377	i386	copy_file_range		sys_copy_file_range

arch/x86/entry/syscalls/syscall_64.tbl

···
 323	common	userfaultfd		sys_userfaultfd
 324	common	membarrier		sys_membarrier
 325	common	mlock2			sys_mlock2
+326	common	copy_file_range		sys_copy_file_range
 
 #
 # x32-specific system call numbers start at 512 to avoid cache impact

fs/btrfs/ctree.h

···
 				struct btrfs_ioctl_space_info *space);
 void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
 			       struct btrfs_ioctl_balance_args *bargs);
-
+ssize_t btrfs_dedupe_file_range(struct file *src_file, u64 loff, u64 olen,
+			   struct file *dst_file, u64 dst_loff);
 
 /* file.c */
 int btrfs_auto_defrag_init(void);
···
 		      loff_t pos, size_t write_bytes,
 		      struct extent_state **cached);
 int btrfs_fdatawrite_range(struct inode *inode, loff_t start, loff_t end);
+ssize_t btrfs_copy_file_range(struct file *file_in, loff_t pos_in,
+			      struct file *file_out, loff_t pos_out,
+			      size_t len, unsigned int flags);
+int btrfs_clone_file_range(struct file *file_in, loff_t pos_in,
+			   struct file *file_out, loff_t pos_out, u64 len);
 
 /* tree-defrag.c */
 int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,

fs/btrfs/file.c

···
 #ifdef CONFIG_COMPAT
 	.compat_ioctl	= btrfs_ioctl,
 #endif
+	.copy_file_range = btrfs_copy_file_range,
+	.clone_file_range = btrfs_clone_file_range,
+	.dedupe_file_range = btrfs_dedupe_file_range,
 };
 
 void btrfs_auto_defrag_exit(void)

fs/btrfs/ioctl.c

···
 		flush_dcache_page(dst_page);
 
 		if (memcmp(addr, dst_addr, cmp_len))
-			ret = BTRFS_SAME_DATA_DIFFERS;
+			ret = -EBADE;
 
 		kunmap_atomic(addr);
 		kunmap_atomic(dst_addr);
···
 
 #define BTRFS_MAX_DEDUPE_LEN	(16 * 1024 * 1024)
 
-static long btrfs_ioctl_file_extent_same(struct file *file,
-			struct btrfs_ioctl_same_args __user *argp)
+ssize_t btrfs_dedupe_file_range(struct file *src_file, u64 loff, u64 olen,
+				struct file *dst_file, u64 dst_loff)
 {
-	struct btrfs_ioctl_same_args *same = NULL;
-	struct btrfs_ioctl_same_extent_info *info;
-	struct inode *src = file_inode(file);
-	u64 off;
-	u64 len;
-	int i;
-	int ret;
-	unsigned long size;
+	struct inode *src = file_inode(src_file);
+	struct inode *dst = file_inode(dst_file);
 	u64 bs = BTRFS_I(src)->root->fs_info->sb->s_blocksize;
-	bool is_admin = capable(CAP_SYS_ADMIN);
-	u16 count;
+	ssize_t res;
 
-	if (!(file->f_mode & FMODE_READ))
-		return -EINVAL;
-
-	ret = mnt_want_write_file(file);
-	if (ret)
-		return ret;
-
-	if (get_user(count, &argp->dest_count)) {
-		ret = -EFAULT;
-		goto out;
-	}
-
-	size = offsetof(struct btrfs_ioctl_same_args __user, info[count]);
-
-	same = memdup_user(argp, size);
-
-	if (IS_ERR(same)) {
-		ret = PTR_ERR(same);
-		same = NULL;
-		goto out;
-	}
-
-	off = same->logical_offset;
-	len = same->length;
-
-	/*
-	 * Limit the total length we will dedupe for each operation.
-	 * This is intended to bound the total time spent in this
-	 * ioctl to something sane.
-	 */
-	if (len > BTRFS_MAX_DEDUPE_LEN)
-		len = BTRFS_MAX_DEDUPE_LEN;
+	if (olen > BTRFS_MAX_DEDUPE_LEN)
+		olen = BTRFS_MAX_DEDUPE_LEN;
 
 	if (WARN_ON_ONCE(bs < PAGE_CACHE_SIZE)) {
 		/*
···
 		 * result, btrfs_cmp_data() won't correctly handle
 		 * this situation without an update.
 		 */
-		ret = -EINVAL;
-		goto out;
+		return -EINVAL;
 	}
 
-	ret = -EISDIR;
-	if (S_ISDIR(src->i_mode))
-		goto out;
-
-	ret = -EACCES;
-	if (!S_ISREG(src->i_mode))
-		goto out;
-
-	/* pre-format output fields to sane values */
-	for (i = 0; i < count; i++) {
-		same->info[i].bytes_deduped = 0ULL;
-		same->info[i].status = 0;
-	}
-
-	for (i = 0, info = same->info; i < count; i++, info++) {
-		struct inode *dst;
-		struct fd dst_file = fdget(info->fd);
-		if (!dst_file.file) {
-			info->status = -EBADF;
-			continue;
-		}
-		dst = file_inode(dst_file.file);
-
-		if (!(is_admin || (dst_file.file->f_mode & FMODE_WRITE))) {
-			info->status = -EINVAL;
-		} else if (file->f_path.mnt != dst_file.file->f_path.mnt) {
-			info->status = -EXDEV;
-		} else if (S_ISDIR(dst->i_mode)) {
-			info->status = -EISDIR;
-		} else if (!S_ISREG(dst->i_mode)) {
-			info->status = -EACCES;
-		} else {
-			info->status = btrfs_extent_same(src, off, len, dst,
-							info->logical_offset);
-			if (info->status == 0)
-				info->bytes_deduped += len;
-		}
-		fdput(dst_file);
-	}
-
-	ret = copy_to_user(argp, same, size);
-	if (ret)
-		ret = -EFAULT;
-
-out:
-	mnt_drop_write_file(file);
-	kfree(same);
-	return ret;
+	res = btrfs_extent_same(src, loff, olen, dst, dst_loff);
+	if (res)
+		return res;
+	return olen;
 }
 
 static int clone_finish_inode_update(struct btrfs_trans_handle *trans,
···
 	return ret;
 }
 
-static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
-				       u64 off, u64 olen, u64 destoff)
+static noinline int btrfs_clone_files(struct file *file, struct file *file_src,
+					u64 off, u64 olen, u64 destoff)
 {
 	struct inode *inode = file_inode(file);
+	struct inode *src = file_inode(file_src);
 	struct btrfs_root *root = BTRFS_I(inode)->root;
-	struct fd src_file;
-	struct inode *src;
 	int ret;
 	u64 len = olen;
 	u64 bs = root->fs_info->sb->s_blocksize;
-	int same_inode = 0;
+	int same_inode = src == inode;
 
 	/*
 	 * TODO:
···
 	 *   be either compressed or non-compressed.
 	 */
 
-	/* the destination must be opened for writing */
-	if (!(file->f_mode & FMODE_WRITE) || (file->f_flags & O_APPEND))
-		return -EINVAL;
-
 	if (btrfs_root_readonly(root))
 		return -EROFS;
 
-	ret = mnt_want_write_file(file);
-	if (ret)
-		return ret;
-
-	src_file = fdget(srcfd);
-	if (!src_file.file) {
-		ret = -EBADF;
-		goto out_drop_write;
-	}
-
-	ret = -EXDEV;
-	if (src_file.file->f_path.mnt != file->f_path.mnt)
-		goto out_fput;
-
-	src = file_inode(src_file.file);
-
-	ret = -EINVAL;
-	if (src == inode)
-		same_inode = 1;
-
-	/* the src must be open for reading */
-	if (!(src_file.file->f_mode & FMODE_READ))
-		goto out_fput;
+	if (file_src->f_path.mnt != file->f_path.mnt ||
+	    src->i_sb != inode->i_sb)
+		return -EXDEV;
 
 	/* don't make the dst file partly checksummed */
 	if ((BTRFS_I(src)->flags & BTRFS_INODE_NODATASUM) !=
 	    (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM))
-		goto out_fput;
+		return -EINVAL;
 
-	ret = -EISDIR;
 	if (S_ISDIR(src->i_mode) || S_ISDIR(inode->i_mode))
-		goto out_fput;
-
-	ret = -EXDEV;
-	if (src->i_sb != inode->i_sb)
-		goto out_fput;
+		return -EISDIR;
 
 	if (!same_inode) {
 		btrfs_double_inode_lock(src, inode);
···
 		btrfs_double_inode_unlock(src, inode);
 	else
 		mutex_unlock(&src->i_mutex);
-out_fput:
-	fdput(src_file);
-out_drop_write:
-	mnt_drop_write_file(file);
 	return ret;
 }
 
-static long btrfs_ioctl_clone_range(struct file *file, void __user *argp)
+ssize_t btrfs_copy_file_range(struct file *file_in, loff_t pos_in,
+			      struct file *file_out, loff_t pos_out,
+			      size_t len, unsigned int flags)
 {
-	struct btrfs_ioctl_clone_range_args args;
+	ssize_t ret;
 
-	if (copy_from_user(&args, argp, sizeof(args)))
-		return -EFAULT;
-	return btrfs_ioctl_clone(file, args.src_fd, args.src_offset,
-				 args.src_length, args.dest_offset);
+	ret = btrfs_clone_files(file_out, file_in, pos_in, len, pos_out);
+	if (ret == 0)
+		ret = len;
+	return ret;
+}
+
+int btrfs_clone_file_range(struct file *src_file, loff_t off,
+		struct file *dst_file, loff_t destoff, u64 len)
+{
+	return btrfs_clone_files(dst_file, src_file, off, len, destoff);
 }
 
 /*
···
 		return btrfs_ioctl_dev_info(root, argp);
 	case BTRFS_IOC_BALANCE:
 		return btrfs_ioctl_balance(file, NULL);
-	case BTRFS_IOC_CLONE:
-		return btrfs_ioctl_clone(file, arg, 0, 0, 0);
-	case BTRFS_IOC_CLONE_RANGE:
-		return btrfs_ioctl_clone_range(file, argp);
 	case BTRFS_IOC_TRANS_START:
 		return btrfs_ioctl_trans_start(file);
 	case BTRFS_IOC_TRANS_END:
···
 		return btrfs_ioctl_get_fslabel(file, argp);
 	case BTRFS_IOC_SET_FSLABEL:
 		return btrfs_ioctl_set_fslabel(file, argp);
-	case BTRFS_IOC_FILE_EXTENT_SAME:
-		return btrfs_ioctl_file_extent_same(file, argp);
 	case BTRFS_IOC_GET_SUPPORTED_FEATURES:
 		return btrfs_ioctl_get_supported_features(file, argp);
 	case BTRFS_IOC_GET_FEATURES:

fs/cifs/cifsfs.c

···
 #endif
 };
 
+static int cifs_clone_file_range(struct file *src_file, loff_t off,
+		struct file *dst_file, loff_t destoff, u64 len)
+{
+	struct inode *src_inode = file_inode(src_file);
+	struct inode *target_inode = file_inode(dst_file);
+	struct cifsFileInfo *smb_file_src = src_file->private_data;
+	struct cifsFileInfo *smb_file_target = dst_file->private_data;
+	struct cifs_tcon *target_tcon = tlink_tcon(smb_file_target->tlink);
+	unsigned int xid;
+	int rc;
+
+	cifs_dbg(FYI, "clone range\n");
+
+	xid = get_xid();
+
+	if (!src_file->private_data || !dst_file->private_data) {
+		rc = -EBADF;
+		cifs_dbg(VFS, "missing cifsFileInfo on copy range src file\n");
+		goto out;
+	}
+
+	/*
+	 * Note: cifs case is easier than btrfs since server responsible for
+	 * checks for proper open modes and file type and if it wants
+	 * server could even support copy of range where source = target
+	 */
+	lock_two_nondirectories(target_inode, src_inode);
+
+	if (len == 0)
+		len = src_inode->i_size - off;
+
+	cifs_dbg(FYI, "about to flush pages\n");
+	/* should we flush first and last page first */
+	truncate_inode_pages_range(&target_inode->i_data, destoff,
+				   PAGE_CACHE_ALIGN(destoff + len)-1);
+
+	if (target_tcon->ses->server->ops->duplicate_extents)
+		rc = target_tcon->ses->server->ops->duplicate_extents(xid,
+			smb_file_src, smb_file_target, off, len, destoff);
+	else
+		rc = -EOPNOTSUPP;
+
+	/* force revalidate of size and timestamps of target file now
+	   that target is updated on the server */
+	CIFS_I(target_inode)->time = 0;
+	/* although unlocking in the reverse order from locking is not
+	   strictly necessary here it is a little cleaner to be consistent */
+	unlock_two_nondirectories(src_inode, target_inode);
+out:
+	free_xid(xid);
+	return rc;
+}
+
 const struct file_operations cifs_file_ops = {
 	.read_iter = cifs_loose_read_iter,
 	.write_iter = cifs_file_write_iter,
···
 	.splice_read = generic_file_splice_read,
 	.llseek = cifs_llseek,
 	.unlocked_ioctl	= cifs_ioctl,
+	.clone_file_range = cifs_clone_file_range,
 	.setlease = cifs_setlease,
 	.fallocate = cifs_fallocate,
 };
···
 	.splice_read = generic_file_splice_read,
 	.llseek = cifs_llseek,
 	.unlocked_ioctl	= cifs_ioctl,
+	.clone_file_range = cifs_clone_file_range,
+	.clone_file_range = cifs_clone_file_range,
 	.setlease = cifs_setlease,
 	.fallocate = cifs_fallocate,
 };
···
 	.mmap = cifs_file_mmap,
 	.splice_read = generic_file_splice_read,
 	.unlocked_ioctl  = cifs_ioctl,
+	.clone_file_range = cifs_clone_file_range,
 	.llseek = cifs_llseek,
 	.setlease = cifs_setlease,
 	.fallocate = cifs_fallocate,
···
 	.splice_read = generic_file_splice_read,
 	.llseek = cifs_llseek,
 	.unlocked_ioctl	= cifs_ioctl,
+	.clone_file_range = cifs_clone_file_range,
 	.setlease = cifs_setlease,
 	.fallocate = cifs_fallocate,
 };
···
 	.splice_read = generic_file_splice_read,
 	.llseek = cifs_llseek,
 	.unlocked_ioctl	= cifs_ioctl,
+	.clone_file_range = cifs_clone_file_range,
 	.setlease = cifs_setlease,
 	.fallocate = cifs_fallocate,
 };
···
 	.mmap = cifs_file_mmap,
 	.splice_read = generic_file_splice_read,
 	.unlocked_ioctl  = cifs_ioctl,
+	.clone_file_range = cifs_clone_file_range,
 	.llseek = cifs_llseek,
 	.setlease = cifs_setlease,
 	.fallocate = cifs_fallocate,
···
 	.release = cifs_closedir,
 	.read    = generic_read_dir,
 	.unlocked_ioctl  = cifs_ioctl,
+	.clone_file_range = cifs_clone_file_range,
 	.llseek = generic_file_llseek,
 };
 

fs/cifs/cifsfs.h

···
 extern ssize_t	cifs_getxattr(struct dentry *, const char *, void *, size_t);
 extern ssize_t	cifs_listxattr(struct dentry *, char *, size_t);
 extern long cifs_ioctl(struct file *filep, unsigned int cmd, unsigned long arg);
-
 #ifdef CONFIG_CIFS_NFSD_EXPORT
 extern const struct export_operations cifs_export_ops;
 #endif /* CONFIG_CIFS_NFSD_EXPORT */

fs/cifs/ioctl.c

···
 #include "cifs_ioctl.h"
 #include <linux/btrfs.h>
 
+static int cifs_file_clone_range(unsigned int xid, struct file *src_file,
+			  struct file *dst_file)
+{
+	struct inode *src_inode = file_inode(src_file);
+	struct inode *target_inode = file_inode(dst_file);
+	struct cifsFileInfo *smb_file_src;
+	struct cifsFileInfo *smb_file_target;
+	struct cifs_tcon *src_tcon;
+	struct cifs_tcon *target_tcon;
+	int rc;
+
+	cifs_dbg(FYI, "ioctl clone range\n");
+
+	if (!src_file->private_data || !dst_file->private_data) {
+		rc = -EBADF;
+		cifs_dbg(VFS, "missing cifsFileInfo on copy range src file\n");
+		goto out;
+	}
+
+	rc = -EXDEV;
+	smb_file_target = dst_file->private_data;
+	smb_file_src = src_file->private_data;
+	src_tcon = tlink_tcon(smb_file_src->tlink);
+	target_tcon = tlink_tcon(smb_file_target->tlink);
+
+	if (src_tcon->ses != target_tcon->ses) {
+		cifs_dbg(VFS, "source and target of copy not on same server\n");
+		goto out;
+	}
+
+	/*
+	 * Note: cifs case is easier than btrfs since server responsible for
+	 * checks for proper open modes and file type and if it wants
+	 * server could even support copy of range where source = target
+	 */
+	lock_two_nondirectories(target_inode, src_inode);
+
+	cifs_dbg(FYI, "about to flush pages\n");
+	/* should we flush first and last page first */
+	truncate_inode_pages(&target_inode->i_data, 0);
+
+	if (target_tcon->ses->server->ops->clone_range)
+		rc = target_tcon->ses->server->ops->clone_range(xid,
+			smb_file_src, smb_file_target, 0, src_inode->i_size, 0);
+	else
+		rc = -EOPNOTSUPP;
+
+	/* force revalidate of size and timestamps of target file now
+	   that target is updated on the server */
+	CIFS_I(target_inode)->time = 0;
+	/* although unlocking in the reverse order from locking is not
+	   strictly necessary here it is a little cleaner to be consistent */
+	unlock_two_nondirectories(src_inode, target_inode);
+out:
+	return rc;
+}
+
 static long cifs_ioctl_clone(unsigned int xid, struct file *dst_file,
-			unsigned long srcfd, u64 off, u64 len, u64 destoff,
-			bool dup_extents)
+			unsigned long srcfd)
 {
 	int rc;
-	struct cifsFileInfo *smb_file_target = dst_file->private_data;
-	struct inode *target_inode = file_inode(dst_file);
-	struct cifs_tcon *target_tcon;
 	struct fd src_file;
-	struct cifsFileInfo *smb_file_src;
 	struct inode *src_inode;
-	struct cifs_tcon *src_tcon;
 
 	cifs_dbg(FYI, "ioctl clone range\n");
 	/* the destination must be opened for writing */
···
 		goto out_fput;
 	}
 
-	if ((!src_file.file->private_data) || (!dst_file->private_data)) {
-		rc = -EBADF;
-		cifs_dbg(VFS, "missing cifsFileInfo on copy range src file\n");
-		goto out_fput;
-	}
-
-	rc = -EXDEV;
-	smb_file_target = dst_file->private_data;
-	smb_file_src = src_file.file->private_data;
-	src_tcon = tlink_tcon(smb_file_src->tlink);
-	target_tcon = tlink_tcon(smb_file_target->tlink);
-
-	/* check source and target on same server (or volume if dup_extents) */
-	if (dup_extents && (src_tcon != target_tcon)) {
-		cifs_dbg(VFS, "source and target of copy not on same share\n");
-		goto out_fput;
-	}
-
-	if (!dup_extents && (src_tcon->ses != target_tcon->ses)) {
-		cifs_dbg(VFS, "source and target of copy not on same server\n");
-		goto out_fput;
-	}
-
 	src_inode = file_inode(src_file.file);
 	rc = -EINVAL;
 	if (S_ISDIR(src_inode->i_mode))
 		goto out_fput;
 
-	/*
-	 * Note: cifs case is easier than btrfs since server responsible for
-	 * checks for proper open modes and file type and if it wants
-	 * server could even support copy of range where source = target
-	 */
-	lock_two_nondirectories(target_inode, src_inode);
+	rc = cifs_file_clone_range(xid, src_file.file, dst_file);
 
-	/* determine range to clone */
-	rc = -EINVAL;
-	if (off + len > src_inode->i_size || off + len < off)
-		goto out_unlock;
-	if (len == 0)
-		len = src_inode->i_size - off;
-
-	cifs_dbg(FYI, "about to flush pages\n");
-	/* should we flush first and last page first */
-	truncate_inode_pages_range(&target_inode->i_data, destoff,
-				   PAGE_CACHE_ALIGN(destoff + len)-1);
-
-	if (dup_extents && target_tcon->ses->server->ops->duplicate_extents)
-		rc = target_tcon->ses->server->ops->duplicate_extents(xid,
-			smb_file_src, smb_file_target, off, len, destoff);
-	else if (!dup_extents && target_tcon->ses->server->ops->clone_range)
-		rc = target_tcon->ses->server->ops->clone_range(xid,
-			smb_file_src, smb_file_target, off, len, destoff);
-	else
-		rc = -EOPNOTSUPP;
-
-	/* force revalidate of size and timestamps of target file now
-	   that target is updated on the server */
-	CIFS_I(target_inode)->time = 0;
-out_unlock:
-	/* although unlocking in the reverse order from locking is not
-	   strictly necessary here it is a little cleaner to be consistent */
-	unlock_two_nondirectories(src_inode, target_inode);
 out_fput:
 	fdput(src_file);
 out_drop_write:
···
 			}
 			break;
 		case CIFS_IOC_COPYCHUNK_FILE:
-			rc = cifs_ioctl_clone(xid, filep, arg, 0, 0, 0, false);
-			break;
-		case BTRFS_IOC_CLONE:
-			rc = cifs_ioctl_clone(xid, filep, arg, 0, 0, 0, true);
+			rc = cifs_ioctl_clone(xid, filep, arg);
 			break;
 		case CIFS_IOC_SET_INTEGRITY:
 			if (pSMBFile == NULL)

fs/compat_ioctl.c

···
 		goto out_fput;
 #endif
 
+	case FICLONE:
+	case FICLONERANGE:
+	case FIDEDUPERANGE:
+		goto do_ioctl;
+
 	case FIBMAP:
 	case FIGETBSZ:
 	case FIONREAD:

fs/ioctl.c

···
 	return error;
 }
 
+static long ioctl_file_clone(struct file *dst_file, unsigned long srcfd,
+			     u64 off, u64 olen, u64 destoff)
+{
+	struct fd src_file = fdget(srcfd);
+	int ret;
+
+	if (!src_file.file)
+		return -EBADF;
+	ret = vfs_clone_file_range(src_file.file, off, dst_file, destoff, olen);
+	fdput(src_file);
+	return ret;
+}
+
+static long ioctl_file_clone_range(struct file *file, void __user *argp)
+{
+	struct file_clone_range args;
+
+	if (copy_from_user(&args, argp, sizeof(args)))
+		return -EFAULT;
+	return ioctl_file_clone(file, args.src_fd, args.src_offset,
+				args.src_length, args.dest_offset);
+}
+
 #ifdef CONFIG_BLOCK
 
 static inline sector_t logical_to_blk(struct inode *inode, loff_t offset)
···
 	return thaw_super(sb);
 }
 
+static long ioctl_file_dedupe_range(struct file *file, void __user *arg)
+{
+	struct file_dedupe_range __user *argp = arg;
+	struct file_dedupe_range *same = NULL;
+	int ret;
+	unsigned long size;
+	u16 count;
+
+	if (get_user(count, &argp->dest_count)) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	size = offsetof(struct file_dedupe_range __user, info[count]);
+
+	same = memdup_user(argp, size);
+	if (IS_ERR(same)) {
+		ret = PTR_ERR(same);
+		same = NULL;
+		goto out;
+	}
+
+	ret = vfs_dedupe_file_range(file, same);
+	if (ret)
+		goto out;
+
+	ret = copy_to_user(argp, same, size);
+	if (ret)
+		ret = -EFAULT;
+
+out:
+	kfree(same);
+	return ret;
+}
+
 /*
  * When you add any new common ioctls to the switches above and below
  * please update compat_sys_ioctl() too.
···
 
 	case FIGETBSZ:
 		return put_user(inode->i_sb->s_blocksize, argp);
+
+	case FICLONE:
+		return ioctl_file_clone(filp, arg, 0, 0, 0);
+
+	case FICLONERANGE:
+		return ioctl_file_clone_range(filp, argp);
+
+	case FIDEDUPERANGE:
+		return ioctl_file_dedupe_range(filp, argp);
 
 	default:
 		if (S_ISREG(inode->i_mode))

fs/locks.c

···
 
 /**
  * locks_mandatory_area - Check for a conflicting lock
- * @read_write: %FLOCK_VERIFY_WRITE for exclusive access, %FLOCK_VERIFY_READ
- *		for shared
- * @inode:      the file to check
+ * @inode:	the file to check
  * @filp:       how the file was opened (if it was)
- * @offset:     start of area to check
- * @count:      length of area to check
+ * @start:	first byte in the file to check
+ * @end:	lastbyte in the file to check
+ * @type:	%F_WRLCK for a write lock, else %F_RDLCK
  *
  * Searches the inode's list of locks to find any POSIX locks which conflict.
- * This function is called from rw_verify_area() and
- * locks_verify_truncate().
  */
-int locks_mandatory_area(int read_write, struct inode *inode,
-			 struct file *filp, loff_t offset,
-			 size_t count)
+int locks_mandatory_area(struct inode *inode, struct file *filp, loff_t start,
+			 loff_t end, unsigned char type)
 {
 	struct file_lock fl;
 	int error;
···
 	fl.fl_flags = FL_POSIX | FL_ACCESS;
 	if (filp && !(filp->f_flags & O_NONBLOCK))
 		sleep = true;
-	fl.fl_type = (read_write == FLOCK_VERIFY_WRITE) ? F_WRLCK : F_RDLCK;
-	fl.fl_start = offset;
-	fl.fl_end = offset + count - 1;
+	fl.fl_type = type;
+	fl.fl_start = start;
+	fl.fl_end = end;
 
 	for (;;) {
 		if (filp) {

fs/nfs/nfs4file.c

···
 	return nfs42_proc_allocate(filep, offset, len);
 }
 
-static noinline long
-nfs42_ioctl_clone(struct file *dst_file, unsigned long srcfd,
-		  u64 src_off, u64 dst_off, u64 count)
+static int nfs42_clone_file_range(struct file *src_file, loff_t src_off,
+		struct file *dst_file, loff_t dst_off, u64 count)
 {
 	struct inode *dst_inode = file_inode(dst_file);
 	struct nfs_server *server = NFS_SERVER(dst_inode);
-	struct fd src_file;
-	struct inode *src_inode;
+	struct inode *src_inode = file_inode(src_file);
 	unsigned int bs = server->clone_blksize;
 	bool same_inode = false;
 	int ret;
-
-	/* dst file must be opened for writing */
-	if (!(dst_file->f_mode & FMODE_WRITE))
-		return -EINVAL;
-
-	ret = mnt_want_write_file(dst_file);
-	if (ret)
-		return ret;
-
-	src_file = fdget(srcfd);
-	if (!src_file.file) {
-		ret = -EBADF;
-		goto out_drop_write;
-	}
-
-	src_inode = file_inode(src_file.file);
-
-	if (src_inode == dst_inode)
-		same_inode = true;
-
-	/* src file must be opened for reading */
-	if (!(src_file.file->f_mode & FMODE_READ))
-		goto out_fput;
-
-	/* src and dst must be regular files */
-	ret = -EISDIR;
-	if (!S_ISREG(src_inode->i_mode) || !S_ISREG(dst_inode->i_mode))
-		goto out_fput;
-
-	ret = -EXDEV;
-	if (src_file.file->f_path.mnt != dst_file->f_path.mnt ||
-	    src_inode->i_sb != dst_inode->i_sb)
-		goto out_fput;
 
 	/* check alignment w.r.t. clone_blksize */
 	ret = -EINVAL;
 	if (bs) {
 		if (!IS_ALIGNED(src_off, bs) || !IS_ALIGNED(dst_off, bs))
-			goto out_fput;
+			goto out;
 		if (!IS_ALIGNED(count, bs) && i_size_read(src_inode) != (src_off + count))
-			goto out_fput;
+			goto out;
 	}
 
-	/* verify if ranges are overlapped within the same file */
-	if (same_inode) {
-		if (dst_off + count > src_off && dst_off < src_off + count)
-			goto out_fput;
-	}
+	if (src_inode == dst_inode)
+		same_inode = true;
 
 	/* XXX: do we lock at all? what if server needs CB_RECALL_LAYOUT? */
 	if (same_inode) {
···
 	if (ret)
 		goto out_unlock;
 
-	ret = nfs42_proc_clone(src_file.file, dst_file, src_off, dst_off, count);
+	ret = nfs42_proc_clone(src_file, dst_file, src_off, dst_off, count);
 
 	/* truncate inode page cache of the dst range so that future reads can fetch
 	 * new data from server */
···
 		mutex_unlock(&dst_inode->i_mutex);
 		mutex_unlock(&src_inode->i_mutex);
 	}
-out_fput:
-	fdput(src_file);
-out_drop_write:
-	mnt_drop_write_file(dst_file);
+out:
 	return ret;
-}
-
-static long nfs42_ioctl_clone_range(struct file *dst_file, void __user *argp)
-{
-	struct btrfs_ioctl_clone_range_args args;
-
-	if (copy_from_user(&args, argp, sizeof(args)))
-		return -EFAULT;
-
-	return nfs42_ioctl_clone(dst_file, args.src_fd, args.src_offset,
-				 args.dest_offset, args.src_length);
-}
-
-long nfs4_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-{
-	void __user *argp = (void __user *)arg;
-
-	switch (cmd) {
-	case BTRFS_IOC_CLONE:
-		return nfs42_ioctl_clone(file, arg, 0, 0, 0);
-	case BTRFS_IOC_CLONE_RANGE:
-		return nfs42_ioctl_clone_range(file, argp);
-	}
-
-	return -ENOTTY;
 }
 #endif /* CONFIG_NFS_V4_2 */
 
···
 #ifdef CONFIG_NFS_V4_2
 	.llseek		= nfs4_file_llseek,
 	.fallocate	= nfs42_fallocate,
-	.unlocked_ioctl = nfs4_ioctl,
-	.compat_ioctl	= nfs4_ioctl,
+	.clone_file_range = nfs42_clone_file_range,
 #else
 	.llseek		= nfs_file_llseek,
 #endif

fs/nfsd/nfs4proc.c

···
 		clear_bit(RQ_SPLICE_OK, &rqstp->rq_flags);
 
 	/* check stateid */
-	status = nfs4_preprocess_stateid_op(rqstp, cstate, &read->rd_stateid,
-			RD_STATE, &read->rd_filp, &read->rd_tmp_file);
+	status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh,
+					&read->rd_stateid, RD_STATE,
+					&read->rd_filp, &read->rd_tmp_file);
 	if (status) {
 		dprintk("NFSD: nfsd4_read: couldn't process stateid!\n");
 		goto out;
···
 
 	if (setattr->sa_iattr.ia_valid & ATTR_SIZE) {
 		status = nfs4_preprocess_stateid_op(rqstp, cstate,
-			&setattr->sa_stateid, WR_STATE, NULL, NULL);
+				&cstate->current_fh, &setattr->sa_stateid,
+				WR_STATE, NULL, NULL);
 		if (status) {
 			dprintk("NFSD: nfsd4_setattr: couldn't process stateid!\n");
 			return status;
···
 	if (write->wr_offset >= OFFSET_MAX)
 		return nfserr_inval;
 
-	status = nfs4_preprocess_stateid_op(rqstp, cstate, stateid, WR_STATE,
-			&filp, NULL);
+	status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh,
+						stateid, WR_STATE, &filp, NULL);
 	if (status) {
 		dprintk("NFSD: nfsd4_write: couldn't process stateid!\n");
 		return status;
···
 }
 
 static __be32
+nfsd4_clone(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+		struct nfsd4_clone *clone)
+{
+	struct file *src, *dst;
+	__be32 status;
+
+	status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->save_fh,
+					    &clone->cl_src_stateid, RD_STATE,
+					    &src, NULL);
+	if (status) {
+		dprintk("NFSD: %s: couldn't process src stateid!\n", __func__);
+		goto out;
+	}
+
+	status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh,
+					    &clone->cl_dst_stateid, WR_STATE,
+					    &dst, NULL);
+	if (status) {
+		dprintk("NFSD: %s: couldn't process dst stateid!\n", __func__);
+		goto out_put_src;
+	}
+
+	/* fix up for NFS-specific error code */
+	if (!S_ISREG(file_inode(src)->i_mode) ||
+	    !S_ISREG(file_inode(dst)->i_mode)) {
+		status = nfserr_wrong_type;
+		goto out_put_dst;
+	}
+
+	status = nfsd4_clone_file_range(src, clone->cl_src_pos,
+			dst, clone->cl_dst_pos, clone->cl_count);
+
+out_put_dst:
+	fput(dst);
+out_put_src:
+	fput(src);
+out:
+	return status;
+}
+
+static __be32
 nfsd4_fallocate(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 		struct nfsd4_fallocate *fallocate, int flags)
 {
 	__be32 status = nfserr_notsupp;
 	struct file *file;
 
-	status = nfs4_preprocess_stateid_op(rqstp, cstate,
+	status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh,
 					    &fallocate->falloc_stateid,
 					    WR_STATE, &file, NULL);
 	if (status != nfs_ok) {
···
 	__be32 status;
 	struct file *file;
 
-	status = nfs4_preprocess_stateid_op(rqstp, cstate,
+	status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh,
 					    &seek->seek_stateid,
 					    RD_STATE, &file, NULL);
 	if (status) {
···
 		.op_func = (nfsd4op_func)nfsd4_deallocate,
 		.op_flags = OP_MODIFIES_SOMETHING | OP_CACHEME,
 		.op_name = "OP_DEALLOCATE",
+		.op_rsize_bop = (nfsd4op_rsize)nfsd4_only_status_rsize,
+	},
+	[OP_CLONE] = {
+		.op_func = (nfsd4op_func)nfsd4_clone,
+		.op_flags = OP_MODIFIES_SOMETHING | OP_CACHEME,
+		.op_name = "OP_CLONE",
 		.op_rsize_bop = (nfsd4op_rsize)nfsd4_only_status_rsize,
 	},
 	[OP_SEEK] = {

fs/nfsd/nfs4state.c

···
  */
 __be32
 nfs4_preprocess_stateid_op(struct svc_rqst *rqstp,
-		struct nfsd4_compound_state *cstate, stateid_t *stateid,
-		int flags, struct file **filpp, bool *tmp_file)
+		struct nfsd4_compound_state *cstate, struct svc_fh *fhp,
+		stateid_t *stateid, int flags, struct file **filpp, bool *tmp_file)
 {
-	struct svc_fh *fhp = &cstate->current_fh;
 	struct inode *ino = d_inode(fhp->fh_dentry);
 	struct net *net = SVC_NET(rqstp);
 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);

fs/nfsd/nfs4xdr.c

···
 }
 
 static __be32
+nfsd4_decode_clone(struct nfsd4_compoundargs *argp, struct nfsd4_clone *clone)
+{
+	DECODE_HEAD;
+
+	status = nfsd4_decode_stateid(argp, &clone->cl_src_stateid);
+	if (status)
+		return status;
+	status = nfsd4_decode_stateid(argp, &clone->cl_dst_stateid);
+	if (status)
+		return status;
+
+	READ_BUF(8 + 8 + 8);
+	p = xdr_decode_hyper(p, &clone->cl_src_pos);
+	p = xdr_decode_hyper(p, &clone->cl_dst_pos);
+	p = xdr_decode_hyper(p, &clone->cl_count);
+	DECODE_TAIL;
+}
+
+static __be32
 nfsd4_decode_seek(struct nfsd4_compoundargs *argp, struct nfsd4_seek *seek)
 {
 	DECODE_HEAD;
···
 	[OP_READ_PLUS]		= (nfsd4_dec)nfsd4_decode_notsupp,
 	[OP_SEEK]		= (nfsd4_dec)nfsd4_decode_seek,
 	[OP_WRITE_SAME]		= (nfsd4_dec)nfsd4_decode_notsupp,
+	[OP_CLONE]		= (nfsd4_dec)nfsd4_decode_clone,
 };
 
 static inline bool
···
 	[OP_READ_PLUS]		= (nfsd4_enc)nfsd4_encode_noop,
 	[OP_SEEK]		= (nfsd4_enc)nfsd4_encode_seek,
 	[OP_WRITE_SAME]		= (nfsd4_enc)nfsd4_encode_noop,
+	[OP_CLONE]		= (nfsd4_enc)nfsd4_encode_noop,
 };
 
 /*

fs/nfsd/state.h

···
 struct nfsd_net;
 
 extern __be32 nfs4_preprocess_stateid_op(struct svc_rqst *rqstp,
-		struct nfsd4_compound_state *cstate, stateid_t *stateid,
-		int flags, struct file **filp, bool *tmp_file);
+		struct nfsd4_compound_state *cstate, struct svc_fh *fhp,
+		stateid_t *stateid, int flags, struct file **filp, bool *tmp_file);
 __be32 nfsd4_lookup_stateid(struct nfsd4_compound_state *cstate,
 		     stateid_t *stateid, unsigned char typemask,
 		     struct nfs4_stid **s, struct nfsd_net *nn);

fs/nfsd/vfs.c

···
 #endif /* CONFIG_NFSD_V3 */
 
 #ifdef CONFIG_NFSD_V4
+#include "../internal.h"
 #include "acl.h"
 #include "idmap.h"
 #endif /* CONFIG_NFSD_V4 */
···
 	return nfserr_notsupp;
 }
 #endif
+
+__be32 nfsd4_clone_file_range(struct file *src, u64 src_pos, struct file *dst,
+		u64 dst_pos, u64 count)
+{
+	return nfserrno(vfs_clone_file_range(src, src_pos, dst, dst_pos,
+			count));
+}
 
 __be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp,
 			   struct file *file, loff_t offset, loff_t len,

fs/nfsd/vfs.h

···
 		    struct xdr_netobj *);
 __be32		nfsd4_vfs_fallocate(struct svc_rqst *, struct svc_fh *,
 				    struct file *, loff_t, loff_t, int);
+__be32		nfsd4_clone_file_range(struct file *, u64, struct file *,
+			u64, u64);
 #endif /* CONFIG_NFSD_V4 */
 __be32		nfsd_create(struct svc_rqst *, struct svc_fh *,
 				char *name, int len, struct iattr *attrs,

fs/nfsd/xdr4.h

···
 	u64		falloc_length;
 };
 
+struct nfsd4_clone {
+	/* request */
+	stateid_t	cl_src_stateid;
+	stateid_t	cl_dst_stateid;
+	u64		cl_src_pos;
+	u64		cl_dst_pos;
+	u64		cl_count;
+};
+
 struct nfsd4_seek {
 	/* request */
 	stateid_t	seek_stateid;
···
 		/* NFSv4.2 */
 		struct nfsd4_fallocate		allocate;
 		struct nfsd4_fallocate		deallocate;
+		struct nfsd4_clone		clone;
 		struct nfsd4_seek		seek;
 	} u;
 	struct nfs4_replay *			replay;

fs/read_write.c

···
 #include <linux/pagemap.h>
 #include <linux/splice.h>
 #include <linux/compat.h>
+#include <linux/mount.h>
 #include "internal.h"
 
 #include <asm/uaccess.h>
···
 	}
 
 	if (unlikely(inode->i_flctx && mandatory_lock(inode))) {
-		retval = locks_mandatory_area(
-			read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE,
-			inode, file, pos, count);
+		retval = locks_mandatory_area(inode, file, pos, pos + count - 1,
+				read_write == READ ? F_RDLCK : F_WRLCK);
 		if (retval < 0)
 			return retval;
 	}
···
 	return do_sendfile(out_fd, in_fd, NULL, count, 0);
 }
 #endif
+
+/*
+ * copy_file_range() differs from regular file read and write in that it
+ * specifically allows return partial success.  When it does so is up to
+ * the copy_file_range method.
+ */
+ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
+			    struct file *file_out, loff_t pos_out,
+			    size_t len, unsigned int flags)
+{
+	struct inode *inode_in = file_inode(file_in);
+	struct inode *inode_out = file_inode(file_out);
+	ssize_t ret;
+
+	if (flags != 0)
+		return -EINVAL;
+
+	/* copy_file_range allows full ssize_t len, ignoring MAX_RW_COUNT  */
+	ret = rw_verify_area(READ, file_in, &pos_in, len);
+	if (ret >= 0)
+		ret = rw_verify_area(WRITE, file_out, &pos_out, len);
+	if (ret < 0)
+		return ret;
+
+	if (!(file_in->f_mode & FMODE_READ) ||
+	    !(file_out->f_mode & FMODE_WRITE) ||
+	    (file_out->f_flags & O_APPEND))
+		return -EBADF;
+
+	/* this could be relaxed once a method supports cross-fs copies */
+	if (inode_in->i_sb != inode_out->i_sb)
+		return -EXDEV;
+
+	if (len == 0)
+		return 0;
+
+	ret = mnt_want_write_file(file_out);
+	if (ret)
+		return ret;
+
+	ret = -EOPNOTSUPP;
+	if (file_out->f_op->copy_file_range)
+		ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out,
+						      pos_out, len, flags);
+	if (ret == -EOPNOTSUPP)
+		ret = do_splice_direct(file_in, &pos_in, file_out, &pos_out,
+				len > MAX_RW_COUNT ? MAX_RW_COUNT : len, 0);
+
+	if (ret > 0) {
+		fsnotify_access(file_in);
+		add_rchar(current, ret);
+		fsnotify_modify(file_out);
+		add_wchar(current, ret);
+	}
+	inc_syscr(current);
+	inc_syscw(current);
+
+	mnt_drop_write_file(file_out);
+
+	return ret;
+}
+EXPORT_SYMBOL(vfs_copy_file_range);
+
+SYSCALL_DEFINE6(copy_file_range, int, fd_in, loff_t __user *, off_in,
+		int, fd_out, loff_t __user *, off_out,
+		size_t, len, unsigned int, flags)
+{
+	loff_t pos_in;
+	loff_t pos_out;
+	struct fd f_in;
+	struct fd f_out;
+	ssize_t ret = -EBADF;
+
+	f_in = fdget(fd_in);
+	if (!f_in.file)
+		goto out2;
+
+	f_out = fdget(fd_out);
+	if (!f_out.file)
+		goto out1;
+
+	ret = -EFAULT;
+	if (off_in) {
+		if (copy_from_user(&pos_in, off_in, sizeof(loff_t)))
+			goto out;
+	} else {
+		pos_in = f_in.file->f_pos;
+	}
+
+	if (off_out) {
+		if (copy_from_user(&pos_out, off_out, sizeof(loff_t)))
+			goto out;
+	} else {
+		pos_out = f_out.file->f_pos;
+	}
+
+	ret = vfs_copy_file_range(f_in.file, pos_in, f_out.file, pos_out, len,
+				  flags);
+	if (ret > 0) {
+		pos_in += ret;
+		pos_out += ret;
+
+		if (off_in) {
+			if (copy_to_user(off_in, &pos_in, sizeof(loff_t)))
+				ret = -EFAULT;
+		} else {
+			f_in.file->f_pos = pos_in;
+		}
+
+		if (off_out) {
+			if (copy_to_user(off_out, &pos_out, sizeof(loff_t)))
+				ret = -EFAULT;
+		} else {
+			f_out.file->f_pos = pos_out;
+		}
+	}
+
+out:
+	fdput(f_out);
+out1:
+	fdput(f_in);
+out2:
+	return ret;
+}
+
+static int clone_verify_area(struct file *file, loff_t pos, u64 len, bool write)
+{
+	struct inode *inode = file_inode(file);
+
+	if (unlikely(pos < 0))
+		return -EINVAL;
+
+	 if (unlikely((loff_t) (pos + len) < 0))
+		return -EINVAL;
+
+	if (unlikely(inode->i_flctx && mandatory_lock(inode))) {
+		loff_t end = len ? pos + len - 1 : OFFSET_MAX;
+		int retval;
+
+		retval = locks_mandatory_area(inode, file, pos, end,
+				write ? F_WRLCK : F_RDLCK);
+		if (retval < 0)
+			return retval;
+	}
+
+	return security_file_permission(file, write ? MAY_WRITE : MAY_READ);
+}
+
+int vfs_clone_file_range(struct file *file_in, loff_t pos_in,
+		struct file *file_out, loff_t pos_out, u64 len)
+{
+	struct inode *inode_in = file_inode(file_in);
+	struct inode *inode_out = file_inode(file_out);
+	int ret;
+
+	if (inode_in->i_sb != inode_out->i_sb ||
+	    file_in->f_path.mnt != file_out->f_path.mnt)
+		return -EXDEV;
+
+	if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))
+		return -EISDIR;
+	if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
+		return -EINVAL;
+
+	if (!(file_in->f_mode & FMODE_READ) ||
+	    !(file_out->f_mode & FMODE_WRITE) ||
+	    (file_out->f_flags & O_APPEND) ||
+	    !file_in->f_op->clone_file_range)
+		return -EBADF;
+
+	ret = clone_verify_area(file_in, pos_in, len, false);
+	if (ret)
+		return ret;
+
+	ret = clone_verify_area(file_out, pos_out, len, true);
+	if (ret)
+		return ret;
+
+	if (pos_in + len > i_size_read(inode_in))
+		return -EINVAL;
+
+	ret = mnt_want_write_file(file_out);
+	if (ret)
+		return ret;
+
+	ret = file_in->f_op->clone_file_range(file_in, pos_in,
+			file_out, pos_out, len);
+	if (!ret) {
+		fsnotify_access(file_in);
+		fsnotify_modify(file_out);
+	}
+
+	mnt_drop_write_file(file_out);
+	return ret;
+}
+EXPORT_SYMBOL(vfs_clone_file_range);
+
+int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
+{
+	struct file_dedupe_range_info *info;
+	struct inode *src = file_inode(file);
+	u64 off;
+	u64 len;
+	int i;
+	int ret;
+	bool is_admin = capable(CAP_SYS_ADMIN);
+	u16 count = same->dest_count;
+	struct file *dst_file;
+	loff_t dst_off;
+	ssize_t deduped;
+
+	if (!(file->f_mode & FMODE_READ))
+		return -EINVAL;
+
+	if (same->reserved1 || same->reserved2)
+		return -EINVAL;
+
+	off = same->src_offset;
+	len = same->src_length;
+
+	ret = -EISDIR;
+	if (S_ISDIR(src->i_mode))
+		goto out;
+
+	ret = -EINVAL;
+	if (!S_ISREG(src->i_mode))
+		goto out;
+
+	ret = clone_verify_area(file, off, len, false);
+	if (ret < 0)
+		goto out;
+	ret = 0;
+
+	/* pre-format output fields to sane values */
+	for (i = 0; i < count; i++) {
+		same->info[i].bytes_deduped = 0ULL;
+		same->info[i].status = FILE_DEDUPE_RANGE_SAME;
+	}
+
+	for (i = 0, info = same->info; i < count; i++, info++) {
+		struct inode *dst;
+		struct fd dst_fd = fdget(info->dest_fd);
+
+		dst_file = dst_fd.file;
+		if (!dst_file) {
+			info->status = -EBADF;
+			goto next_loop;
+		}
+		dst = file_inode(dst_file);
+
+		ret = mnt_want_write_file(dst_file);
+		if (ret) {
+			info->status = ret;
+			goto next_loop;
+		}
+
+		dst_off = info->dest_offset;
+		ret = clone_verify_area(dst_file, dst_off, len, true);
+		if (ret < 0) {
+			info->status = ret;
+			goto next_file;
+		}
+		ret = 0;
+
+		if (info->reserved) {
+			info->status = -EINVAL;
+		} else if (!(is_admin || (dst_file->f_mode & FMODE_WRITE))) {
+			info->status = -EINVAL;
+		} else if (file->f_path.mnt != dst_file->f_path.mnt) {
+			info->status = -EXDEV;
+		} else if (S_ISDIR(dst->i_mode)) {
+			info->status = -EISDIR;
+		} else if (dst_file->f_op->dedupe_file_range == NULL) {
+			info->status = -EINVAL;
+		} else {
+			deduped = dst_file->f_op->dedupe_file_range(file, off,
+							len, dst_file,
+							info->dest_offset);
+			if (deduped == -EBADE)
+				info->status = FILE_DEDUPE_RANGE_DIFFERS;
+			else if (deduped < 0)
+				info->status = deduped;
+			else
+				info->bytes_deduped += deduped;
+		}
+
+next_file:
+		mnt_drop_write_file(dst_file);
+next_loop:
+		fdput(dst_fd);
+	}
+
+out:
+	return ret;
+}
+EXPORT_SYMBOL(vfs_dedupe_file_range);

include/linux/fs.h

···
 #ifndef CONFIG_MMU
 	unsigned (*mmap_capabilities)(struct file *);
 #endif
+	ssize_t (*copy_file_range)(struct file *, loff_t, struct file *,
+			loff_t, size_t, unsigned int);
+	int (*clone_file_range)(struct file *, loff_t, struct file *, loff_t,
+			u64);
+	ssize_t (*dedupe_file_range)(struct file *, u64, u64, struct file *,
+			u64);
 };
 
 struct inode_operations {
···
 		unsigned long, loff_t *);
 extern ssize_t vfs_writev(struct file *, const struct iovec __user *,
 		unsigned long, loff_t *);
+extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *,
+				   loff_t, size_t, unsigned int);
+extern int vfs_clone_file_range(struct file *file_in, loff_t pos_in,
+		struct file *file_out, loff_t pos_out, u64 len);
+extern int vfs_dedupe_file_range(struct file *file,
+				 struct file_dedupe_range *same);
 
 struct super_operations {
    	struct inode *(*alloc_inode)(struct super_block *sb);
···
 
 #define MAX_RW_COUNT (INT_MAX & PAGE_CACHE_MASK)
 
-#define FLOCK_VERIFY_READ  1
-#define FLOCK_VERIFY_WRITE 2
-
 #ifdef CONFIG_MANDATORY_FILE_LOCKING
 extern int locks_mandatory_locked(struct file *);
-extern int locks_mandatory_area(int, struct inode *, struct file *, loff_t, size_t);
+extern int locks_mandatory_area(struct inode *, struct file *, loff_t, loff_t, unsigned char);
 
 /*
  * Candidates for mandatory locking have the setgid bit set
···
 }
 
 static inline int locks_verify_truncate(struct inode *inode,
-				    struct file *filp,
+				    struct file *f,
 				    loff_t size)
 {
-	if (inode->i_flctx && mandatory_lock(inode))
-		return locks_mandatory_area(
-			FLOCK_VERIFY_WRITE, inode, filp,
-			size < inode->i_size ? size : inode->i_size,
-			(size < inode->i_size ? inode->i_size - size
-			 : size - inode->i_size)
-		);
-	return 0;
+	if (!inode->i_flctx || !mandatory_lock(inode))
+		return 0;
+
+	if (size < inode->i_size) {
+		return locks_mandatory_area(inode, f, size, inode->i_size - 1,
+				F_WRLCK);
+	} else {
+		return locks_mandatory_area(inode, f, inode->i_size, size - 1,
+				F_WRLCK);
+	}
 }
 
 #else /* !CONFIG_MANDATORY_FILE_LOCKING */
···
 	return 0;
 }
 
-static inline int locks_mandatory_area(int rw, struct inode *inode,
-				       struct file *filp, loff_t offset,
-				       size_t count)
+static inline int locks_mandatory_area(struct inode *inode, struct file *filp,
+                                       loff_t start, loff_t end, unsigned char type)
 {
 	return 0;
 }

include/linux/nfs4.h

···
 Needs to be updated if more operations are defined in future.*/
 
 #define FIRST_NFS4_OP	OP_ACCESS
-#define LAST_NFS4_OP 	OP_WRITE_SAME
 #define LAST_NFS40_OP	OP_RELEASE_LOCKOWNER
 #define LAST_NFS41_OP	OP_RECLAIM_COMPLETE
-#define LAST_NFS42_OP	OP_WRITE_SAME
+#define LAST_NFS42_OP	OP_CLONE
+#define LAST_NFS4_OP	LAST_NFS42_OP
 
 enum nfsstat4 {
 	NFS4_OK = 0,

include/linux/syscalls.h

···
 			const char __user *const __user *envp, int flags);
 
 asmlinkage long sys_membarrier(int cmd, int flags);
+asmlinkage long sys_copy_file_range(int fd_in, loff_t __user *off_in,
+				    int fd_out, loff_t __user *off_out,
+				    size_t len, unsigned int flags);
 
 asmlinkage long sys_mlock2(unsigned long start, size_t len, int flags);
 

include/uapi/asm-generic/unistd.h

···
 __SYSCALL(__NR_membarrier, sys_membarrier)
 #define __NR_mlock2 284
 __SYSCALL(__NR_mlock2, sys_mlock2)
+#define __NR_copy_file_range 285
+__SYSCALL(__NR_copy_file_range, sys_copy_file_range)
 
 #undef __NR_syscalls
-#define __NR_syscalls 285
+#define __NR_syscalls 286
 
 /*
  * All syscalls below here should go away really,

include/uapi/linux/fs.h

···
 #define RENAME_EXCHANGE		(1 << 1)	/* Exchange source and dest */
 #define RENAME_WHITEOUT		(1 << 2)	/* Whiteout source */
 
+struct file_clone_range {
+	__s64 src_fd;
+	__u64 src_offset;
+	__u64 src_length;
+	__u64 dest_offset;
+};
+
 struct fstrim_range {
 	__u64 start;
 	__u64 len;
 	__u64 minlen;
+};
+
+/* extent-same (dedupe) ioctls; these MUST match the btrfs ioctl definitions */
+#define FILE_DEDUPE_RANGE_SAME		0
+#define FILE_DEDUPE_RANGE_DIFFERS	1
+
+/* from struct btrfs_ioctl_file_extent_same_info */
+struct file_dedupe_range_info {
+	__s64 dest_fd;		/* in - destination file */
+	__u64 dest_offset;	/* in - start of extent in destination */
+	__u64 bytes_deduped;	/* out - total # of bytes we were able
+				 * to dedupe from this file. */
+	/* status of this dedupe operation:
+	 * < 0 for error
+	 * == FILE_DEDUPE_RANGE_SAME if dedupe succeeds
+	 * == FILE_DEDUPE_RANGE_DIFFERS if data differs
+	 */
+	__s32 status;		/* out - see above description */
+	__u32 reserved;		/* must be zero */
+};
+
+/* from struct btrfs_ioctl_file_extent_same_args */
+struct file_dedupe_range {
+	__u64 src_offset;	/* in - start of extent in source */
+	__u64 src_length;	/* in - length of extent */
+	__u16 dest_count;	/* in - total elements in info array */
+	__u16 reserved1;	/* must be zero */
+	__u32 reserved2;	/* must be zero */
+	struct file_dedupe_range_info info[0];
 };
 
 /* And dynamically-tunable limits and defaults: */
···
 #define FIFREEZE	_IOWR('X', 119, int)	/* Freeze */
 #define FITHAW		_IOWR('X', 120, int)	/* Thaw */
 #define FITRIM		_IOWR('X', 121, struct fstrim_range)	/* Trim */
+#define FICLONE		_IOW(0x94, 9, int)
+#define FICLONERANGE	_IOW(0x94, 13, struct file_clone_range)
+#define FIDEDUPERANGE	_IOWR(0x94, 54, struct file_dedupe_range)
 
 #define	FS_IOC_GETFLAGS			_IOR('f', 1, long)
 #define	FS_IOC_SETFLAGS			_IOW('f', 2, long)

kernel/sys_ni.c

···
 cond_syscall(sys_setfsgid);
 cond_syscall(sys_capget);
 cond_syscall(sys_capset);
+cond_syscall(sys_copy_file_range);
 
 /* arch-specific weak syscall entries */
 cond_syscall(sys_pciconfig_read);