diff options
Diffstat (limited to 'fs/btrfs/file-item.c')
| -rw-r--r-- | fs/btrfs/file-item.c | 831 |
1 files changed, 831 insertions, 0 deletions
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c new file mode 100644 index 000000000000..964652435fd1 --- /dev/null +++ b/fs/btrfs/file-item.c @@ -0,0 +1,831 @@ +/* + * Copyright (C) 2007 Oracle. All rights reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License v2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public + * License along with this program; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 021110-1307, USA. + */ + +#include <linux/bio.h> +#include <linux/pagemap.h> +#include <linux/highmem.h> +#include "ctree.h" +#include "disk-io.h" +#include "transaction.h" +#include "print-tree.h" + +#define MAX_CSUM_ITEMS(r, size) ((((BTRFS_LEAF_DATA_SIZE(r) - \ + sizeof(struct btrfs_item) * 2) / \ + size) - 1)) + +#define MAX_ORDERED_SUM_BYTES(r) ((PAGE_SIZE - \ + sizeof(struct btrfs_ordered_sum)) / \ + sizeof(struct btrfs_sector_sum) * \ + (r)->sectorsize - (r)->sectorsize) + +int btrfs_insert_file_extent(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + u64 objectid, u64 pos, + u64 disk_offset, u64 disk_num_bytes, + u64 num_bytes, u64 offset, u64 ram_bytes, + u8 compression, u8 encryption, u16 other_encoding) +{ + int ret = 0; + struct btrfs_file_extent_item *item; + struct btrfs_key file_key; + struct btrfs_path *path; + struct extent_buffer *leaf; + + path = btrfs_alloc_path(); + BUG_ON(!path); + file_key.objectid = objectid; + file_key.offset = pos; + btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY); + + ret = btrfs_insert_empty_item(trans, root, path, &file_key, + sizeof(*item)); + if (ret < 0) + goto out; + BUG_ON(ret); + 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, disk_offset); + btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes); + btrfs_set_file_extent_offset(leaf, item, offset); + btrfs_set_file_extent_num_bytes(leaf, item, num_bytes); + btrfs_set_file_extent_ram_bytes(leaf, item, ram_bytes); + btrfs_set_file_extent_generation(leaf, item, trans->transid); + btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG); + btrfs_set_file_extent_compression(leaf, item, compression); + btrfs_set_file_extent_encryption(leaf, item, encryption); + btrfs_set_file_extent_other_encoding(leaf, item, other_encoding); + + btrfs_mark_buffer_dirty(leaf); +out: + btrfs_free_path(path); + return ret; +} + +struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, + u64 bytenr, int cow) +{ + int ret; + struct btrfs_key file_key; + struct btrfs_key found_key; + struct btrfs_csum_item *item; + struct extent_buffer *leaf; + u64 csum_offset = 0; + u16 csum_size = + btrfs_super_csum_size(&root->fs_info->super_copy); + int csums_in_item; + + file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID; + file_key.offset = bytenr; + btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY); + ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow); + if (ret < 0) + goto fail; + leaf = path->nodes[0]; + if (ret > 0) { + ret = 1; + if (path->slots[0] == 0) + goto fail; + path->slots[0]--; + btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); + if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY) + goto fail; + + csum_offset = (bytenr - found_key.offset) >> + root->fs_info->sb->s_blocksize_bits; + csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]); + csums_in_item /= csum_size; + + if (csum_offset >= csums_in_item) { + ret = -EFBIG; + goto fail; + } + } + item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item); + item = (struct btrfs_csum_item *)((unsigned char *)item + + csum_offset * csum_size); + return item; +fail: + if (ret > 0) + ret = -ENOENT; + return ERR_PTR(ret); +} + + +int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, u64 objectid, + u64 offset, int mod) +{ + int ret; + struct btrfs_key file_key; + int ins_len = mod < 0 ? -1 : 0; + int cow = mod != 0; + + file_key.objectid = objectid; + file_key.offset = offset; + btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY); + ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow); + return ret; +} + + +int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode, + struct bio *bio, u32 *dst) +{ + u32 sum; + struct bio_vec *bvec = bio->bi_io_vec; + int bio_index = 0; + u64 offset; + u64 item_start_offset = 0; + u64 item_last_offset = 0; + u64 disk_bytenr; + u32 diff; + u16 csum_size = + btrfs_super_csum_size(&root->fs_info->super_copy); + int ret; + struct btrfs_path *path; + struct btrfs_csum_item *item = NULL; + struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; + + path = btrfs_alloc_path(); + if (bio->bi_size > PAGE_CACHE_SIZE * 8) + path->reada = 2; + + WARN_ON(bio->bi_vcnt <= 0); + + disk_bytenr = (u64)bio->bi_sector << 9; + while (bio_index < bio->bi_vcnt) { + offset = page_offset(bvec->bv_page) + bvec->bv_offset; + ret = btrfs_find_ordered_sum(inode, offset, disk_bytenr, &sum); + if (ret == 0) + goto found; + + if (!item || disk_bytenr < item_start_offset || + disk_bytenr >= item_last_offset) { + struct btrfs_key found_key; + u32 item_size; + + if (item) + btrfs_release_path(root, path); + item = btrfs_lookup_csum(NULL, root->fs_info->csum_root, + path, disk_bytenr, 0); + if (IS_ERR(item)) { + ret = PTR_ERR(item); + if (ret == -ENOENT || ret == -EFBIG) + ret = 0; + sum = 0; + if (BTRFS_I(inode)->root->root_key.objectid == + BTRFS_DATA_RELOC_TREE_OBJECTID) { + set_extent_bits(io_tree, offset, + offset + bvec->bv_len - 1, + EXTENT_NODATASUM, GFP_NOFS); + } else { + printk(KERN_INFO "btrfs no csum found " + "for inode %lu start %llu\n", + inode->i_ino, + (unsigned long long)offset); + } + item = NULL; + btrfs_release_path(root, path); + goto found; + } + btrfs_item_key_to_cpu(path->nodes[0], &found_key, + path->slots[0]); + + item_start_offset = found_key.offset; + item_size = btrfs_item_size_nr(path->nodes[0], + path->slots[0]); + item_last_offset = item_start_offset + + (item_size / csum_size) * + root->sectorsize; + item = btrfs_item_ptr(path->nodes[0], path->slots[0], + struct btrfs_csum_item); + } + /* + * this byte range must be able to fit inside + * a single leaf so it will also fit inside a u32 + */ + diff = disk_bytenr - item_start_offset; + diff = diff / root->sectorsize; + diff = diff * csum_size; + + read_extent_buffer(path->nodes[0], &sum, + ((unsigned long)item) + diff, + csum_size); +found: + if (dst) + *dst++ = sum; + else + set_state_private(io_tree, offset, sum); + disk_bytenr += bvec->bv_len; + bio_index++; + bvec++; + } + btrfs_free_path(path); + return 0; +} + +int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end, + struct list_head *list) +{ + struct btrfs_key key; + struct btrfs_path *path; + struct extent_buffer *leaf; + struct btrfs_ordered_sum *sums; + struct btrfs_sector_sum *sector_sum; + struct btrfs_csum_item *item; + unsigned long offset; + int ret; + size_t size; + u64 csum_end; + u16 csum_size = btrfs_super_csum_size(&root->fs_info->super_copy); + + path = btrfs_alloc_path(); + BUG_ON(!path); + + key.objectid = BTRFS_EXTENT_CSUM_OBJECTID; + key.offset = start; + key.type = BTRFS_EXTENT_CSUM_KEY; + + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret < 0) + goto fail; + if (ret > 0 && path->slots[0] > 0) { + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1); + if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID && + key.type == BTRFS_EXTENT_CSUM_KEY) { + offset = (start - key.offset) >> + root->fs_info->sb->s_blocksize_bits; + if (offset * csum_size < + btrfs_item_size_nr(leaf, path->slots[0] - 1)) + path->slots[0]--; + } + } + + while (start <= end) { + leaf = path->nodes[0]; + if (path->slots[0] >= btrfs_header_nritems(leaf)) { + ret = btrfs_next_leaf(root, path); + if (ret < 0) + goto fail; + if (ret > 0) + break; + leaf = path->nodes[0]; + } + + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID || + key.type != BTRFS_EXTENT_CSUM_KEY) + break; + + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + if (key.offset > end) + break; + + if (key.offset > start) + start = key.offset; + + size = btrfs_item_size_nr(leaf, path->slots[0]); + csum_end = key.offset + (size / csum_size) * root->sectorsize; + if (csum_end <= start) { + path->slots[0]++; + continue; + } + + csum_end = min(csum_end, end + 1); + item = btrfs_item_ptr(path->nodes[0], path->slots[0], + struct btrfs_csum_item); + while (start < csum_end) { + size = min_t(size_t, csum_end - start, + MAX_ORDERED_SUM_BYTES(root)); + sums = kzalloc(btrfs_ordered_sum_size(root, size), + GFP_NOFS); + BUG_ON(!sums); + + sector_sum = sums->sums; + sums->bytenr = start; + sums->len = size; + + offset = (start - key.offset) >> + root->fs_info->sb->s_blocksize_bits; + offset *= csum_size; + + while (size > 0) { + read_extent_buffer(path->nodes[0], + §or_sum->sum, + ((unsigned long)item) + + offset, csum_size); + sector_sum->bytenr = start; + + size -= root->sectorsize; + start += root->sectorsize; + offset += csum_size; + sector_sum++; + } + list_add_tail(&sums->list, list); + } + path->slots[0]++; + } + ret = 0; +fail: + btrfs_free_path(path); + return ret; +} + +int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode, + struct bio *bio, u64 file_start, int contig) +{ + struct btrfs_ordered_sum *sums; + struct btrfs_sector_sum *sector_sum; + struct btrfs_ordered_extent *ordered; + char *data; + struct bio_vec *bvec = bio->bi_io_vec; + int bio_index = 0; + unsigned long total_bytes = 0; + unsigned long this_sum_bytes = 0; + u64 offset; + u64 disk_bytenr; + + WARN_ON(bio->bi_vcnt <= 0); + sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS); + if (!sums) + return -ENOMEM; + + sector_sum = sums->sums; + disk_bytenr = (u64)bio->bi_sector << 9; + sums->len = bio->bi_size; + INIT_LIST_HEAD(&sums->list); + + if (contig) + offset = file_start; + else + offset = page_offset(bvec->bv_page) + bvec->bv_offset; + + ordered = btrfs_lookup_ordered_extent(inode, offset); + BUG_ON(!ordered); + sums->bytenr = ordered->start; + + while (bio_index < bio->bi_vcnt) { + if (!contig) + offset = page_offset(bvec->bv_page) + bvec->bv_offset; + + if (!contig && (offset >= ordered->file_offset + ordered->len || + offset < ordered->file_offset)) { + unsigned long bytes_left; + sums->len = this_sum_bytes; + this_sum_bytes = 0; + btrfs_add_ordered_sum(inode, ordered, sums); + btrfs_put_ordered_extent(ordered); + + bytes_left = bio->bi_size - total_bytes; + + sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left), + GFP_NOFS); + BUG_ON(!sums); + sector_sum = sums->sums; + sums->len = bytes_left; + ordered = btrfs_lookup_ordered_extent(inode, offset); + BUG_ON(!ordered); + sums->bytenr = ordered->start; + } + + data = kmap_atomic(bvec->bv_page, KM_USER0); + sector_sum->sum = ~(u32)0; + sector_sum->sum = btrfs_csum_data(root, + data + bvec->bv_offset, + sector_sum->sum, + bvec->bv_len); + kunmap_atomic(data, KM_USER0); + btrfs_csum_final(sector_sum->sum, + (char *)§or_sum->sum); + sector_sum->bytenr = disk_bytenr; + + sector_sum++; + bio_index++; + total_bytes += bvec->bv_len; + this_sum_bytes += bvec->bv_len; + disk_bytenr += bvec->bv_len; + offset += bvec->bv_len; + bvec++; + } + this_sum_bytes = 0; + btrfs_add_ordered_sum(inode, ordered, sums); + btrfs_put_ordered_extent(ordered); + return 0; +} + +/* + * helper function for csum removal, this expects the + * key to describe the csum pointed to by the path, and it expects + * the csum to overlap the range [bytenr, len] + * + * The csum should not be entirely contained in the range and the + * range should not be entirely contained in the csum. + * + * This calls btrfs_truncate_item with the correct args based on the + * overlap, and fixes up the key as required. + */ +static noinline int truncate_one_csum(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, + struct btrfs_key *key, + u64 bytenr, u64 len) +{ + struct extent_buffer *leaf; + u16 csum_size = + btrfs_super_csum_size(&root->fs_info->super_copy); + u64 csum_end; + u64 end_byte = bytenr + len; + u32 blocksize_bits = root->fs_info->sb->s_blocksize_bits; + int ret; + + leaf = path->nodes[0]; + csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size; + csum_end <<= root->fs_info->sb->s_blocksize_bits; + csum_end += key->offset; + + if (key->offset < bytenr && csum_end <= end_byte) { + /* + * [ bytenr - len ] + * [ ] + * [csum ] + * A simple truncate off the end of the item + */ + u32 new_size = (bytenr - key->offset) >> blocksize_bits; + new_size *= csum_size; + ret = btrfs_truncate_item(trans, root, path, new_size, 1); + BUG_ON(ret); + } else if (key->offset >= bytenr && csum_end > end_byte && + end_byte > key->offset) { + /* + * [ bytenr - len ] + * [ ] + * [csum ] + * we need to truncate from the beginning of the csum + */ + u32 new_size = (csum_end - end_byte) >> blocksize_bits; + new_size *= csum_size; + + ret = btrfs_truncate_item(trans, root, path, new_size, 0); + BUG_ON(ret); + + key->offset = end_byte; + ret = btrfs_set_item_key_safe(trans, root, path, key); + BUG_ON(ret); + } else { + BUG(); + } + return 0; +} + +/* + * deletes the csum items from the csum tree for a given + * range of bytes. + */ +int btrfs_del_csums(struct btrfs_trans_handle *trans, + struct btrfs_root *root, u64 bytenr, u64 len) +{ + struct btrfs_path *path; + struct btrfs_key key; + u64 end_byte = bytenr + len; + u64 csum_end; + struct extent_buffer *leaf; + int ret; + u16 csum_size = + btrfs_super_csum_size(&root->fs_info->super_copy); + int blocksize_bits = root->fs_info->sb->s_blocksize_bits; + + root = root->fs_info->csum_root; + + path = btrfs_alloc_path(); + + while (1) { + key.objectid = BTRFS_EXTENT_CSUM_OBJECTID; + key.offset = end_byte - 1; + key.type = BTRFS_EXTENT_CSUM_KEY; + + ret = btrfs_search_slot(trans, root, &key, path, -1, 1); + if (ret > 0) { + if (path->slots[0] == 0) + goto out; + path->slots[0]--; + } + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + + if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID || + key.type != BTRFS_EXTENT_CSUM_KEY) { + break; + } + + if (key.offset >= end_byte) + break; + + csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size; + csum_end <<= blocksize_bits; + csum_end += key.offset; + + /* this csum ends before we start, we're done */ + if (csum_end <= bytenr) + break; + + /* delete the entire item, it is inside our range */ + if (key.offset >= bytenr && csum_end <= end_byte) { + ret = btrfs_del_item(trans, root, path); + BUG_ON(ret); + if (key.offset == bytenr) + break; + } else if (key.offset < bytenr && csum_end > end_byte) { + unsigned long offset; + unsigned long shift_len; + unsigned long item_offset; + /* + * [ bytenr - len ] + * [csum ] + * + * Our bytes are in the middle of the csum, + * we need to split this item and insert a new one. + * + * But we can't drop the path because the + * csum could change, get removed, extended etc. + * + * The trick here is the max size of a csum item leaves + * enough room in the tree block for a single + * item header. So, we split the item in place, + * adding a new header pointing to the existing + * bytes. Then we loop around again and we have + * a nicely formed csum item that we can neatly + * truncate. + */ + offset = (bytenr - key.offset) >> blocksize_bits; + offset *= csum_size; + + shift_len = (len >> blocksize_bits) * csum_size; + + item_offset = btrfs_item_ptr_offset(leaf, + path->slots[0]); + + memset_extent_buffer(leaf, 0, item_offset + offset, + shift_len); + key.offset = bytenr; + + /* + * btrfs_split_item returns -EAGAIN when the + * item changed size or key + */ + ret = btrfs_split_item(trans, root, path, &key, offset); + BUG_ON(ret && ret != -EAGAIN); + + key.offset = end_byte - 1; + } else { + ret = truncate_one_csum(trans, root, path, + &key, bytenr, len); + BUG_ON(ret); + if (key.offset < bytenr) + break; + } + btrfs_release_path(root, path); + } +out: + btrfs_free_path(path); + return 0; +} + +int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_ordered_sum *sums) +{ + u64 bytenr; + int ret; + struct btrfs_key file_key; + struct btrfs_key found_key; + u64 next_offset; + u64 total_bytes = 0; + int found_next; + struct btrfs_path *path; + struct btrfs_csum_item *item; + struct btrfs_csum_item *item_end; + struct extent_buffer *leaf = NULL; + u64 csum_offset; + struct btrfs_sector_sum *sector_sum; + u32 nritems; + u32 ins_size; + char *eb_map; + char *eb_token; + unsigned long map_len; + unsigned long map_start; + u16 csum_size = + btrfs_super_csum_size(&root->fs_info->super_copy); + + path = btrfs_alloc_path(); + BUG_ON(!path); + sector_sum = sums->sums; +again: + next_offset = (u64)-1; + found_next = 0; + file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID; + file_key.offset = sector_sum->bytenr; + bytenr = sector_sum->bytenr; + btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY); + + item = btrfs_lookup_csum(trans, root, path, sector_sum->bytenr, 1); + if (!IS_ERR(item)) { + leaf = path->nodes[0]; + ret = 0; + goto found; + } + ret = PTR_ERR(item); + if (ret == -EFBIG) { + u32 item_size; + /* we found one, but it isn't big enough yet */ + leaf = path->nodes[0]; + item_size = btrfs_item_size_nr(leaf, path->slots[0]); + if ((item_size / csum_size) >= + MAX_CSUM_ITEMS(root, csum_size)) { + /* already at max size, make a new one */ + goto insert; + } + } else { + int slot = path->slots[0] + 1; + /* we didn't find a csum item, insert one */ + nritems = btrfs_header_nritems(path->nodes[0]); + if (path->slots[0] >= nritems - 1) { + ret = btrfs_next_leaf(root, path); + if (ret == 1) + found_next = 1; + if (ret != 0) + goto insert; + slot = 0; + } + btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot); + if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID || + found_key.type != BTRFS_EXTENT_CSUM_KEY) { + found_next = 1; + goto insert; + } + next_offset = found_key.offset; + found_next = 1; + goto insert; + } + + /* + * at this point, we know the tree has an item, but it isn't big + * enough yet to put our csum in. Grow it + */ + btrfs_release_path(root, path); + ret = btrfs_search_slot(trans, root, &file_key, path, + csum_size, 1); + if (ret < 0) + goto fail_unlock; + + if (ret > 0) { + if (path->slots[0] == 0) + goto insert; + path->slots[0]--; + } + + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); + csum_offset = (bytenr - found_key.offset) >> + root->fs_info->sb->s_blocksize_bits; + + if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY || + found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID || + csum_offset >= MAX_CSUM_ITEMS(root, csum_size)) { + goto insert; + } + + if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) / + csum_size) { + u32 diff = (csum_offset + 1) * csum_size; + + /* + * is the item big enough already? we dropped our lock + * before and need to recheck + */ + if (diff < btrfs_item_size_nr(leaf, path->slots[0])) + goto csum; + + diff = diff - btrfs_item_size_nr(leaf, path->slots[0]); + if (diff != csum_size) + goto insert; + + ret = btrfs_extend_item(trans, root, path, diff); + BUG_ON(ret); + goto csum; + } + +insert: + btrfs_release_path(root, path); + csum_offset = 0; + if (found_next) { + u64 tmp = total_bytes + root->sectorsize; + u64 next_sector = sector_sum->bytenr; + struct btrfs_sector_sum *next = sector_sum + 1; + + while (tmp < sums->len) { + if (next_sector + root->sectorsize != next->bytenr) + break; + tmp += root->sectorsize; + next_sector = next->bytenr; + next++; + } + tmp = min(tmp, next_offset - file_key.offset); + tmp >>= root->fs_info->sb->s_blocksize_bits; + tmp = max((u64)1, tmp); + tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root, csum_size)); + ins_size = csum_size * tmp; + } else { + ins_size = csum_size; + } + ret = btrfs_insert_empty_item(trans, root, path, &file_key, + ins_size); + if (ret < 0) + goto fail_unlock; + if (ret != 0) { + WARN_ON(1); + goto fail_unlock; + } +csum: + leaf = path->nodes[0]; + item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item); + ret = 0; + item = (struct btrfs_csum_item *)((unsigned char *)item + + csum_offset * csum_size); +found: + item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item); + item_end = (struct btrfs_csum_item *)((unsigned char *)item_end + + btrfs_item_size_nr(leaf, path->slots[0])); + eb_token = NULL; + cond_resched(); +next_sector: + + if (!eb_token || + (unsigned long)item + csum_size >= map_start + map_len) { + int err; + + if (eb_token) + unmap_extent_buffer(leaf, eb_token, KM_USER1); + eb_token = NULL; + err = map_private_extent_buffer(leaf, (unsigned long)item, + csum_size, + &eb_token, &eb_map, + &map_start, &map_len, KM_USER1); + if (err) + eb_token = NULL; + } + if (eb_token) { + memcpy(eb_token + ((unsigned long)item & (PAGE_CACHE_SIZE - 1)), + §or_sum->sum, csum_size); + } else { + write_extent_buffer(leaf, §or_sum->sum, + (unsigned long)item, csum_size); + } + + total_bytes += root->sectorsize; + sector_sum++; + if (total_bytes < sums->len) { + item = (struct btrfs_csum_item *)((char *)item + + csum_size); + if (item < item_end && bytenr + PAGE_CACHE_SIZE == + sector_sum->bytenr) { + bytenr = sector_sum->bytenr; + goto next_sector; + } + } + if (eb_token) { + unmap_extent_buffer(leaf, eb_token, KM_USER1); + eb_token = NULL; + } + btrfs_mark_buffer_dirty(path->nodes[0]); + cond_resched(); + if (total_bytes < sums->len) { + btrfs_release_path(root, path); + goto again; + } +out: + btrfs_free_path(path); + return ret; + +fail_unlock: + goto out; +} |