Btrfs: cow file extents before writing
Signed-off-by: Chris Mason <chris.mason@oracle.com>
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d0dbc6245c
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@ -1020,7 +1020,7 @@ static int btrfs_get_block_lock(struct inode *inode, sector_t iblock,
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ret = btrfs_lookup_file_extent(trans, root, path,
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inode->i_ino,
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iblock << inode->i_blkbits, 0);
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iblock << inode->i_blkbits, 1);
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if (ret < 0) {
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err = ret;
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goto out;
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@ -1040,9 +1040,25 @@ static int btrfs_get_block_lock(struct inode *inode, sector_t iblock,
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blocknr = btrfs_file_extent_disk_blocknr(item);
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blocknr += btrfs_file_extent_offset(item);
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/* exact match found, use it */
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/* exact match found, use it, FIXME, deal with extents
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* other than the page size
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*/
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if (ret == 0) {
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err = 0;
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BUG_ON(btrfs_file_extent_disk_num_blocks(item) != 1);
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if (btrfs_file_extent_generation(item) != trans->transid) {
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struct btrfs_key ins;
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ret = btrfs_alloc_extent(trans, root, 1,
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blocknr, (u64)-1, &ins);
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BUG_ON(ret);
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btrfs_set_file_extent_disk_blocknr(item, ins.objectid);
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mark_buffer_dirty(path->nodes[0]);
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ret = btrfs_free_extent(trans, root,
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blocknr, 1, 0);
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BUG_ON(ret);
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blocknr = ins.objectid;
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}
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map_bh(result, inode->i_sb, blocknr);
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goto out;
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}
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