mirror of
https://github.com/kdave/btrfs-progs
synced 2024-12-11 17:06:32 +00:00
102 lines
2.5 KiB
C
102 lines
2.5 KiB
C
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/*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#include "ctree.h"
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#include "internal.h"
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#include "check/common.h"
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/*
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* Search in csum tree to find how many bytes of range [@start, @start + @len)
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* has the corresponding csum item.
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*
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* @start: range start
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* @len: range length
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* @found: return value of found csum bytes
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* unit is BYTE.
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*/
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int count_csum_range(struct btrfs_fs_info *fs_info, u64 start,
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u64 len, u64 *found)
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{
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struct btrfs_key key;
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struct btrfs_path path;
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struct extent_buffer *leaf;
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int ret;
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size_t size;
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*found = 0;
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u64 csum_end;
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u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
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btrfs_init_path(&path);
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key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
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key.offset = start;
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key.type = BTRFS_EXTENT_CSUM_KEY;
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ret = btrfs_search_slot(NULL, fs_info->csum_root,
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&key, &path, 0, 0);
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if (ret < 0)
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goto out;
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if (ret > 0 && path.slots[0] > 0) {
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leaf = path.nodes[0];
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btrfs_item_key_to_cpu(leaf, &key, path.slots[0] - 1);
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if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
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key.type == BTRFS_EXTENT_CSUM_KEY)
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path.slots[0]--;
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}
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while (len > 0) {
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leaf = path.nodes[0];
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if (path.slots[0] >= btrfs_header_nritems(leaf)) {
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ret = btrfs_next_leaf(fs_info->csum_root, &path);
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if (ret > 0)
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break;
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else if (ret < 0)
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goto out;
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leaf = path.nodes[0];
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}
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btrfs_item_key_to_cpu(leaf, &key, path.slots[0]);
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if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
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key.type != BTRFS_EXTENT_CSUM_KEY)
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break;
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btrfs_item_key_to_cpu(leaf, &key, path.slots[0]);
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if (key.offset >= start + len)
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break;
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if (key.offset > start)
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start = key.offset;
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size = btrfs_item_size_nr(leaf, path.slots[0]);
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csum_end = key.offset + (size / csum_size) *
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fs_info->sectorsize;
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if (csum_end > start) {
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size = min(csum_end - start, len);
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len -= size;
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start += size;
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*found += size;
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}
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path.slots[0]++;
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}
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out:
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btrfs_release_path(&path);
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if (ret < 0)
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return ret;
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return 0;
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}
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