Btrfs: Clone file data ioctl

Add a new ioctl to clone file data

Signed-off-by: Chris Mason <chris.mason@oracle.com>

5 files changed, 179 insertions, 11 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 73b92dd150ff..3b6f8524a4ad 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1516,9 +1516,9 @@ int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
 /* file-item.c */
 int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
                                struct btrfs_root *root,
-                               u64 objectid, u64 pos, u64 offset,
+                               u64 objectid, u64 pos, u64 disk_offset,
                                u64 disk_num_bytes,
-                               u64 num_bytes);
+                             u64 num_bytes, u64 offset);
 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
                              struct btrfs_root *root,
                              struct btrfs_path *path, u64 objectid,
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 9259aece6ed1..f537eb43c2c6 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -28,10 +28,10 @@
                                sizeof(struct btrfs_item) * 2) / \
                                BTRFS_CRC32_SIZE) - 1))
 int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
-                               struct btrfs_root *root,
-                               u64 objectid, u64 pos,
-                               u64 offset, u64 disk_num_bytes,
-                               u64 num_bytes)
+                             struct btrfs_root *root,
+                             u64 objectid, u64 pos,
+                             u64 disk_offset, u64 disk_num_bytes,
+                             u64 num_bytes, u64 offset)
 {
         int ret = 0;
         struct btrfs_file_extent_item *item;
@@ -53,9 +53,9 @@ int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
         leaf = path->nodes[0];
         item = btrfs_item_ptr(leaf, path->slots[0],
                               struct btrfs_file_extent_item);
-        btrfs_set_file_extent_disk_bytenr(leaf, item, offset);
+        btrfs_set_file_extent_disk_bytenr(leaf, item, disk_offset);
         btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes);
-        btrfs_set_file_extent_offset(leaf, item, 0);
+        btrfs_set_file_extent_offset(leaf, item, offset);
         btrfs_set_file_extent_num_bytes(leaf, item, num_bytes);
         btrfs_set_file_extent_generation(leaf, item, trans->transid);
         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 8effdf4f5d6f..a50507f3056d 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -285,7 +285,7 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
                         err = btrfs_insert_file_extent(trans, root,
                                                        inode->i_ino,
                                                        last_pos_in_file,
-                                                       0, 0, hole_size);
+                                                       0, 0, hole_size, 0);
                         btrfs_drop_extent_cache(inode, last_pos_in_file,
                                         last_pos_in_file + hole_size -1);
                         btrfs_check_file(root, inode);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 994834474590..c6fae29c0b9e 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -19,6 +19,7 @@
 #include <linux/kernel.h>
 #include <linux/bio.h>
 #include <linux/buffer_head.h>
+#include <linux/file.h>
 #include <linux/fs.h>
 #include <linux/pagemap.h>
 #include <linux/highmem.h>
@@ -141,7 +142,7 @@ static int cow_file_range(struct inode *inode, u64 start, u64 end)
                 cur_alloc_size = ins.offset;
                 ret = btrfs_insert_file_extent(trans, root, inode->i_ino,
                                                start, ins.objectid, ins.offset,
-                                               ins.offset);
+                                               ins.offset, 0);
                 inode->i_blocks += ins.offset >> 9;
                 btrfs_check_file(root, inode);
                 if (num_bytes < cur_alloc_size) {
@@ -1227,7 +1228,7 @@ static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
                         err = btrfs_insert_file_extent(trans, root,
                                                        inode->i_ino,
                                                        hole_start, 0, 0,
-                                                       hole_size);
+                                                       hole_size, 0);
                         btrfs_drop_extent_cache(inode, hole_start,
                                                 (u64)-1);
                         btrfs_check_file(root, inode);
@@ -3100,6 +3101,170 @@ out:
         return ret;
 }
 
+void dup_item_to_inode(struct btrfs_trans_handle *trans,
+                       struct btrfs_root *root,
+                       struct btrfs_path *path,
+                       struct extent_buffer *leaf,
+                       int slot,
+                       struct btrfs_key *key,
+                       u64 destino)
+{
+        struct btrfs_path *cpath = btrfs_alloc_path();
+        int len = btrfs_item_size_nr(leaf, slot);
+        int dstoff;
+        struct btrfs_key ckey = *key;
+        int ret;
+
+        ckey.objectid = destino;
+        ret = btrfs_insert_empty_item(trans, root, cpath, &ckey, len);
+        dstoff = btrfs_item_ptr_offset(cpath->nodes[0], cpath->slots[0]);
+        copy_extent_buffer(cpath->nodes[0], leaf, dstoff,
+                           btrfs_item_ptr_offset(leaf, slot),
+                           len);
+        btrfs_release_path(root, cpath);
+}
+
+long btrfs_ioctl_clone(struct file *file, unsigned long src_fd)
+{
+        struct inode *inode = fdentry(file)->d_inode;
+        struct btrfs_root *root = BTRFS_I(inode)->root;
+        struct file *src_file;
+        struct inode *src;
+        struct btrfs_trans_handle *trans;
+        int ret;
+        u64 pos;
+        struct btrfs_path *path;
+        struct btrfs_key key;
+        struct extent_buffer *leaf;
+        u32 nritems;
+        int nextret;
+        int slot;
+
+        src_file = fget(src_fd);
+        if (!src_file)
+                return -EBADF;
+        src = src_file->f_dentry->d_inode;
+
+        ret = -EXDEV;
+        if (src->i_sb != inode->i_sb)
+                goto out_fput;
+
+        if (inode < src) {
+                mutex_lock(&inode->i_mutex);
+                mutex_lock(&src->i_mutex);
+        } else {
+                mutex_lock(&src->i_mutex);
+                mutex_lock(&inode->i_mutex);
+        }
+
+        ret = -ENOTEMPTY;
+        if (inode->i_size)
+                goto out_unlock;
+
+        /* do any pending delalloc/csum calc on src, one way or
+           another, and lock file content */
+        while (1) {
+                filemap_write_and_wait(src->i_mapping);
+                lock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
+                if (BTRFS_I(src)->delalloc_bytes == 0)
+                        break;
+                unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
+        }
+
+        mutex_lock(&root->fs_info->fs_mutex);
+        trans = btrfs_start_transaction(root, 0);
+        path = btrfs_alloc_path();
+        pos = 0;
+        while (1) {
+                ret = btrfs_lookup_file_extent(trans, root, path, src->i_ino,
+                                               pos, 0);
+                if (ret < 0)
+                        goto out;
+                if (ret > 0) {
+                        if (path->slots[0] == 0) {
+                                ret = 0;
+                                goto out;
+                        }
+                        path->slots[0]--;
+                }
+next_slot:
+                leaf = path->nodes[0];
+                slot = path->slots[0];
+                btrfs_item_key_to_cpu(leaf, &key, slot);
+                nritems = btrfs_header_nritems(leaf);
+
+                if (btrfs_key_type(&key) > BTRFS_CSUM_ITEM_KEY ||
+                    key.objectid != src->i_ino)
+                        goto out;
+                if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
+                        struct btrfs_file_extent_item *extent;
+                        int found_type;
+                        pos = key.offset;
+                        extent = btrfs_item_ptr(leaf, slot,
+                                                struct btrfs_file_extent_item);
+                        found_type = btrfs_file_extent_type(leaf, extent);
+                        if (found_type == BTRFS_FILE_EXTENT_REG) {
+                                u64 len = btrfs_file_extent_num_bytes(leaf,
+                                                                      extent);
+                                u64 ds = btrfs_file_extent_disk_bytenr(leaf,
+                                                                       extent);
+                                u64 dl = btrfs_file_extent_disk_num_bytes(leaf,
+                                                                 extent);
+                                u64 off = btrfs_file_extent_offset(leaf,
+                                                                   extent);
+                                btrfs_insert_file_extent(trans, root,
+                                                         inode->i_ino, pos,
+                                                         ds, dl, len, off);
+                                /* ds == 0 means there's a hole */
+                                if (ds != 0) {
+                                        btrfs_inc_extent_ref(trans, root,
+                                                     ds, dl,
+                                                     root->root_key.objectid,
+                                                     trans->transid,
+                                                     inode->i_ino, pos);
+                                }
+                                pos = key.offset + len;
+                        } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
+                                dup_item_to_inode(trans, root, path, leaf, slot,
+                                                  &key, inode->i_ino);
+                                pos = key.offset + btrfs_item_size_nr(leaf,
+                                                                      slot);
+                        }
+                } else if (btrfs_key_type(&key) == BTRFS_CSUM_ITEM_KEY)
+                        dup_item_to_inode(trans, root, path, leaf, slot, &key,
+                                          inode->i_ino);
+
+                if (slot >= nritems - 1) {
+                        nextret = btrfs_next_leaf(root, path);
+                        if (nextret)
+                                goto out;
+                } else {
+                        path->slots[0]++;
+                }
+                goto next_slot;
+        }
+
+out:
+        btrfs_free_path(path);
+        ret = 0;
+
+        inode->i_blocks = src->i_blocks;
+        i_size_write(inode, src->i_size);
+        btrfs_update_inode(trans, root, inode);
+
+        unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
+
+        btrfs_end_transaction(trans, root);
+        mutex_unlock(&root->fs_info->fs_mutex);
+
+out_unlock:
+        mutex_unlock(&src->i_mutex);
+        mutex_unlock(&inode->i_mutex);
+out_fput:
+        fput(src_file);
+        return ret;
+}
+
 long btrfs_ioctl(struct file *file, unsigned int
                 cmd, unsigned long arg)
 {
@@ -3116,6 +3281,8 @@ long btrfs_ioctl(struct file *file, unsigned int
                 return btrfs_ioctl_add_dev(root, (void __user *)arg);
         case BTRFS_IOC_BALANCE:
                 return btrfs_balance(root->fs_info->dev_root);
+        case BTRFS_IOC_CLONE:
+                return btrfs_ioctl_clone(file, arg);
         }
 
         return -ENOTTY;
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 8ad35fc4ba56..b0e73f51d636 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -36,6 +36,7 @@ struct btrfs_ioctl_vol_args {
                                    struct btrfs_ioctl_vol_args)
 #define BTRFS_IOC_SCAN_DEV _IOW(BTRFS_IOCTL_MAGIC, 4, \
                                    struct btrfs_ioctl_vol_args)
+#define BTRFS_IOC_CLONE        _IOW(BTRFS_IOCTL_MAGIC, 9, int)
 #define BTRFS_IOC_ADD_DEV _IOW(BTRFS_IOCTL_MAGIC, 10, \
                                    struct btrfs_ioctl_vol_args)
 #define BTRFS_IOC_RM_DEV _IOW(BTRFS_IOCTL_MAGIC, 11, \