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Btrfs: Clone file data ioctl
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Add a new ioctl to clone file data

Signed-off-by: Chris Mason <chris.mason@oracle.com>
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Sage Weil authored and Chris Mason committed Sep 25, 2008
1 parent d6bfde8 commit f2eb0a2
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Showing 5 changed files with 179 additions and 11 deletions.
4 changes: 2 additions & 2 deletions fs/btrfs/ctree.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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,
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12 changes: 6 additions & 6 deletions fs/btrfs/file-item.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand All @@ -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);
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2 changes: 1 addition & 1 deletion fs/btrfs/file.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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);
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171 changes: 169 additions & 2 deletions fs/btrfs/inode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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>
Expand Down Expand Up @@ -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) {
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -3100,6 +3101,170 @@ long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
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)
{
Expand All @@ -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;
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1 change: 1 addition & 0 deletions fs/btrfs/ioctl.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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, \
Expand Down

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