Btrfs: Clone file data ioctl
authorSage Weil <sage@newdream.net>
Fri, 2 May 2008 18:43:14 +0000 (14:43 -0400)
committerChris Mason <chris.mason@oracle.com>
Thu, 25 Sep 2008 15:04:02 +0000 (11:04 -0400)
Add a new ioctl to clone file data

Signed-off-by: Chris Mason <chris.mason@oracle.com>
fs/btrfs/ctree.h
fs/btrfs/file-item.c
fs/btrfs/file.c
fs/btrfs/inode.c
fs/btrfs/ioctl.h

index 73b92dd..3b6f852 100644 (file)
@@ -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,
index 9259aec..f537eb4 100644 (file)
                               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);
index 8effdf4..a50507f 100644 (file)
@@ -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);
index 9948344..c6fae29 100644 (file)
@@ -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;
index 8ad35fc..b0e73f5 100644 (file)
@@ -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, \