int write_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct extent_buffer *eb)
{
int ret;
int dev_nr;
u64 length;
struct btrfs_multi_bio *multi = NULL;
if (check_tree_block(root, eb))
BUG();
if (!btrfs_buffer_uptodate(eb, trans->transid))
BUG();
btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
csum_tree_block(root, eb, 0);
dev_nr = 0;
length = eb->len;
ret = btrfs_map_block(&root->fs_info->mapping_tree, WRITE,
eb->start, &length, &multi, 0);
while(dev_nr < multi->num_stripes) {
BUG_ON(ret);
eb->fd = multi->stripes[dev_nr].dev->fd;
eb->dev_bytenr = multi->stripes[dev_nr].physical;
multi->stripes[dev_nr].dev->total_ios++;
dev_nr++;
ret = write_extent_to_disk(eb);
BUG_ON(ret);
}
kfree(multi);
return 0;
}
static int write_raid56_with_parity(struct btrfs_fs_info *info,
struct extent_buffer *eb,
struct btrfs_multi_bio *multi,
u64 stripe_len, u64 *raid_map)
{
struct extent_buffer *ebs[multi->num_stripes], *p_eb = NULL, *q_eb = NULL;
int i;
int j;
int ret;
int alloc_size = eb->len;
if (stripe_len > alloc_size)
alloc_size = stripe_len;
split_eb_for_raid56(info, eb, ebs, stripe_len, raid_map,
multi->num_stripes);
for (i = 0; i < multi->num_stripes; i++) {
struct extent_buffer *new_eb;
if (raid_map[i] < BTRFS_RAID5_P_STRIPE) {
ebs[i]->dev_bytenr = multi->stripes[i].physical;
ebs[i]->fd = multi->stripes[i].dev->fd;
multi->stripes[i].dev->total_ios++;
BUG_ON(ebs[i]->start != raid_map[i]);
continue;
}
new_eb = kmalloc(sizeof(*eb) + alloc_size, GFP_NOFS);
BUG_ON(!new_eb);
new_eb->dev_bytenr = multi->stripes[i].physical;
new_eb->fd = multi->stripes[i].dev->fd;
multi->stripes[i].dev->total_ios++;
new_eb->len = stripe_len;
if (raid_map[i] == BTRFS_RAID5_P_STRIPE)
p_eb = new_eb;
else if (raid_map[i] == BTRFS_RAID6_Q_STRIPE)
q_eb = new_eb;
}
if (q_eb) {
void *pointers[multi->num_stripes];
ebs[multi->num_stripes - 2] = p_eb;
ebs[multi->num_stripes - 1] = q_eb;
for (i = 0; i < multi->num_stripes; i++)
pointers[i] = ebs[i]->data;
raid6_gen_syndrome(multi->num_stripes, stripe_len, pointers);
} else {
ebs[multi->num_stripes - 1] = p_eb;
memcpy(p_eb->data, ebs[0]->data, stripe_len);
for (j = 1; j < multi->num_stripes - 1; j++) {
for (i = 0; i < stripe_len; i += sizeof(unsigned long)) {
*(unsigned long *)(p_eb->data + i) ^=
*(unsigned long *)(ebs[j]->data + i);
}
}
}
for (i = 0; i < multi->num_stripes; i++) {
ret = write_extent_to_disk(ebs[i]);
BUG_ON(ret);
if (ebs[i] != eb)
kfree(ebs[i]);
}
return 0;
}