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Btrfs: progress on file_write

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Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason
2007-04-17 13:26:50 -04:00
committed by David Woodhouse
parent 6567e837df
commit b18c668581
5 changed files with 394 additions and 49 deletions
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57
fs/btrfs/ctree.c
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@@ -1249,6 +1249,63 @@ static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
return ret;
}
int btrfs_truncate_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
u32 new_size)
{
int ret = 0;
int slot;
int slot_orig;
struct btrfs_leaf *leaf;
struct buffer_head *leaf_buf;
u32 nritems;
unsigned int data_end;
unsigned int old_data_start;
unsigned int old_size;
unsigned int size_diff;
int i;
slot_orig = path->slots[0];
leaf_buf = path->nodes[0];
leaf = btrfs_buffer_leaf(leaf_buf);
nritems = btrfs_header_nritems(&leaf->header);
data_end = leaf_data_end(root, leaf);
slot = path->slots[0];
old_data_start = btrfs_item_offset(leaf->items + slot);
old_size = btrfs_item_size(leaf->items + slot);
BUG_ON(old_size <= new_size);
size_diff = old_size - new_size;
BUG_ON(slot < 0);
BUG_ON(slot >= nritems);
/*
* item0..itemN ... dataN.offset..dataN.size .. data0.size
*/
/* first correct the data pointers */
for (i = slot; i < nritems; i++) {
u32 ioff = btrfs_item_offset(leaf->items + i);
btrfs_set_item_offset(leaf->items + i,
ioff + size_diff);
}
/* shift the data */
printk("truncate item, new_size %u old_size %u, diff %u, bufp %p, dst, %p, num %u, old_data_start %u, data_end %u\n", new_size, old_size, size_diff, leaf, btrfs_leaf_data(leaf) + data_end + size_diff, old_data_start-data_end, old_data_start, data_end);
btrfs_memmove(root, leaf, btrfs_leaf_data(leaf) +
data_end + size_diff, btrfs_leaf_data(leaf) +
data_end, old_data_start + new_size - data_end);
btrfs_set_item_size(leaf->items + slot, new_size);
btrfs_mark_buffer_dirty(leaf_buf);
ret = 0;
if (btrfs_leaf_free_space(root, leaf) < 0)
BUG();
check_leaf(root, path, 0);
return ret;
}
int btrfs_extend_item(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, u32 data_size)
{