5 files changed, 173 insertions, 0 deletions

diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index 70d4b104c08d..eab31e74b9cc 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -1582,6 +1582,7 @@ COMPAT_SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd,
 
         case FICLONE:
         case FICLONERANGE:
+        case FIDEDUPERANGE:
                 goto do_ioctl;
 
         case FIBMAP:
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 84c6e79829ab..fcdd33b7ec78 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -568,6 +568,41 @@ static int ioctl_fsthaw(struct file *filp)
         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.
@@ -629,6 +664,9 @@ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
         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))
                         error = file_ioctl(filp, cmd, arg);
diff --git a/fs/read_write.c b/fs/read_write.c
index 60ee26941231..2116e74a83d3 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1523,3 +1523,103 @@ int vfs_clone_file_range(struct file *file_in, loff_t pos_in,
         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);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 5d987aefcf1e..d71814b81a3c 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1633,6 +1633,8 @@ struct file_operations {
                         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 {
@@ -1688,6 +1690,8 @@ 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);
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index cd5db7fb3cb7..b38e647664a0 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -52,6 +52,35 @@ struct fstrim_range {
         __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: */
 struct files_stat_struct {
         unsigned long nr_files;         /* read only */
@@ -168,6 +197,7 @@ struct inodes_stat_t {
 #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)