[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit
Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/os/linux/linux-3.4.x/fs/btrfs/file-item.c b/ap/os/linux/linux-3.4.x/fs/btrfs/file-item.c
new file mode 100644
index 0000000..6eab2dd
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/fs/btrfs/file-item.c
@@ -0,0 +1,861 @@
+/*
+ * 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/slab.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_CSUM_ITEMS(r, size) (min(__MAX_CSUM_ITEMS(r, size), PAGE_CACHE_SIZE))
+
+#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();
+ if (!path)
+ return -ENOMEM;
+ file_key.objectid = objectid;
+ file_key.offset = pos;
+ btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
+
+ path->leave_spinning = 1;
+ ret = btrfs_insert_empty_item(trans, root, path, &file_key,
+ sizeof(*item));
+ if (ret < 0)
+ goto out;
+ BUG_ON(ret); /* Can't happen */
+ 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;
+}
+
+
+static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
+ struct inode *inode, struct bio *bio,
+ u64 logical_offset, u32 *dst, int dio)
+{
+ u32 sum;
+ struct bio_vec *bvec = bio->bi_io_vec;
+ int bio_index = 0;
+ u64 offset = 0;
+ 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 (!path)
+ return -ENOMEM;
+ if (bio->bi_size > PAGE_CACHE_SIZE * 8)
+ path->reada = 2;
+
+ WARN_ON(bio->bi_vcnt <= 0);
+
+ /*
+ * the free space stuff is only read when it hasn't been
+ * updated in the current transaction. So, we can safely
+ * read from the commit root and sidestep a nasty deadlock
+ * between reading the free space cache and updating the csum tree.
+ */
+ if (btrfs_is_free_space_inode(root, inode)) {
+ path->search_commit_root = 1;
+ path->skip_locking = 1;
+ }
+
+ disk_bytenr = (u64)bio->bi_sector << 9;
+ if (dio)
+ offset = logical_offset;
+ while (bio_index < bio->bi_vcnt) {
+ if (!dio)
+ 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(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 %llu start %llu\n",
+ (unsigned long long)
+ btrfs_ino(inode),
+ (unsigned long long)offset);
+ }
+ item = NULL;
+ btrfs_release_path(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;
+ offset += bvec->bv_len;
+ bio_index++;
+ bvec++;
+ }
+ btrfs_free_path(path);
+ return 0;
+}
+
+int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode,
+ struct bio *bio, u32 *dst)
+{
+ return __btrfs_lookup_bio_sums(root, inode, bio, 0, dst, 0);
+}
+
+int btrfs_lookup_bio_sums_dio(struct btrfs_root *root, struct inode *inode,
+ struct bio *bio, u64 offset, u32 *dst)
+{
+ return __btrfs_lookup_bio_sums(root, inode, bio, offset, dst, 1);
+}
+
+int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
+ struct list_head *list, int search_commit)
+{
+ 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;
+ LIST_HEAD(tmplist);
+ 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();
+ if (!path)
+ return -ENOMEM;
+
+ if (search_commit) {
+ path->skip_locking = 1;
+ path->reada = 2;
+ path->search_commit_root = 1;
+ }
+
+ 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);
+ if (!sums) {
+ ret = -ENOMEM;
+ goto fail;
+ }
+
+ 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, &tmplist);
+ }
+ path->slots[0]++;
+ }
+ ret = 0;
+fail:
+ while (ret < 0 && !list_empty(&tmplist)) {
+ sums = list_entry(tmplist.next, struct btrfs_ordered_sum, list);
+ list_del(&sums->list);
+ kfree(sums);
+ }
+ list_splice_tail(&tmplist, list);
+
+ 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); /* Logic error */
+ 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); /* -ENOMEM */
+ sector_sum = sums->sums;
+ sums->len = bytes_left;
+ ordered = btrfs_lookup_ordered_extent(inode, offset);
+ BUG_ON(!ordered); /* Logic error */
+ sums->bytenr = ordered->start;
+ }
+
+ data = kmap_atomic(bvec->bv_page);
+ 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);
+ 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 void 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;
+
+ 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;
+ btrfs_truncate_item(trans, root, path, new_size, 1);
+ } 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;
+
+ btrfs_truncate_item(trans, root, path, new_size, 0);
+
+ key->offset = end_byte;
+ btrfs_set_item_key_safe(trans, root, path, key);
+ } else {
+ BUG();
+ }
+}
+
+/*
+ * 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();
+ if (!path)
+ return -ENOMEM;
+
+ while (1) {
+ key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
+ key.offset = end_byte - 1;
+ key.type = BTRFS_EXTENT_CSUM_KEY;
+
+ path->leave_spinning = 1;
+ ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+ if (ret > 0) {
+ if (path->slots[0] == 0)
+ break;
+ path->slots[0]--;
+ } else 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;
+ }
+
+ 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);
+ if (ret)
+ goto out;
+ 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);
+ if (ret && ret != -EAGAIN) {
+ btrfs_abort_transaction(trans, root, ret);
+ goto out;
+ }
+
+ key.offset = end_byte - 1;
+ } else {
+ truncate_one_csum(trans, root, path, &key, bytenr, len);
+ if (key.offset < bytenr)
+ break;
+ }
+ btrfs_release_path(path);
+ }
+ ret = 0;
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+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;
+ u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ 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 && ret != -ENOENT)
+ goto fail_unlock;
+
+ 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(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;
+
+ btrfs_extend_item(trans, root, path, diff);
+ goto csum;
+ }
+
+insert:
+ btrfs_release_path(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;
+ }
+ path->leave_spinning = 1;
+ ret = btrfs_insert_empty_item(trans, root, path, &file_key,
+ ins_size);
+ path->leave_spinning = 0;
+ 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]));
+next_sector:
+
+ 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;
+ }
+ }
+
+ btrfs_mark_buffer_dirty(path->nodes[0]);
+ if (total_bytes < sums->len) {
+ btrfs_release_path(path);
+ cond_resched();
+ goto again;
+ }
+out:
+ btrfs_free_path(path);
+ return ret;
+
+fail_unlock:
+ goto out;
+}