diff options
Diffstat (limited to 'volumes.c')
| -rw-r--r-- | volumes.c | 147 |
1 files changed, 147 insertions, 0 deletions
@@ -189,6 +189,10 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, int flags) list_for_each(cur, head) { device = list_entry(cur, struct btrfs_device, dev_list); + if (!device->name) { + printk("no name for device %llu, skip it now\n", device->devid); + continue; + } fd = open(device->name, flags); if (fd < 0) { @@ -1769,3 +1773,146 @@ struct list_head *btrfs_scanned_uuids(void) { return &fs_uuids; } + +static int rmw_eb(struct btrfs_fs_info *info, + struct extent_buffer *eb, struct extent_buffer *orig_eb) +{ + int ret; + unsigned long orig_off = 0; + unsigned long dest_off = 0; + unsigned long copy_len = eb->len; + + ret = read_whole_eb(info, eb, 0); + if (ret) + return ret; + + if (eb->start + eb->len <= orig_eb->start || + eb->start >= orig_eb->start + orig_eb->len) + return 0; + /* + * | ----- orig_eb ------- | + * | ----- stripe ------- | + * | ----- orig_eb ------- | + * | ----- orig_eb ------- | + */ + if (eb->start > orig_eb->start) + orig_off = eb->start - orig_eb->start; + if (orig_eb->start > eb->start) + dest_off = orig_eb->start - eb->start; + + if (copy_len > orig_eb->len - orig_off) + copy_len = orig_eb->len - orig_off; + if (copy_len > eb->len - dest_off) + copy_len = eb->len - dest_off; + + memcpy(eb->data + dest_off, orig_eb->data + orig_off, copy_len); + return 0; +} + +static void split_eb_for_raid56(struct btrfs_fs_info *info, + struct extent_buffer *orig_eb, + struct extent_buffer **ebs, + u64 stripe_len, u64 *raid_map, + int num_stripes) +{ + struct extent_buffer *eb; + u64 start = orig_eb->start; + u64 this_eb_start; + int i; + int ret; + + for (i = 0; i < num_stripes; i++) { + if (raid_map[i] >= BTRFS_RAID5_P_STRIPE) + break; + + eb = malloc(sizeof(struct extent_buffer) + stripe_len); + if (!eb) + BUG(); + memset(eb, 0, sizeof(struct extent_buffer) + stripe_len); + + eb->start = raid_map[i]; + eb->len = stripe_len; + eb->refs = 1; + eb->flags = 0; + eb->fd = -1; + eb->dev_bytenr = (u64)-1; + + this_eb_start = raid_map[i]; + + if (start > this_eb_start || + start + orig_eb->len < this_eb_start + stripe_len) { + ret = rmw_eb(info, eb, orig_eb); + BUG_ON(ret); + } else { + memcpy(eb->data, orig_eb->data + eb->start - start, stripe_len); + } + ebs[i] = eb; + } +} + +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; +} |