On Sat, Mar 20, 2010 at 12:24 PM, Sean Bartell
<wingedtachikoma@xxxxxxxxx> wrote:
> An extent_io_tree is used for all free space information. This allows
> removal of ext2_alloc_block and ext2_free_block, and makes
> create_ext2_image less ext2-specific.
> ---
> convert.c | 154 +++++++++++++++++++++++++++++++++++++++----------------------
> 1 files changed, 99 insertions(+), 55 deletions(-)
>
> diff --git a/convert.c b/convert.c
> index d037c98..c48f8ba 100644
> --- a/convert.c
> +++ b/convert.c
> @@ -95,29 +95,10 @@ static int close_ext2fs(ext2_filsys fs)
> return 0;
> }
>
> -static int ext2_alloc_block(ext2_filsys fs, u64 goal, u64 *block_ret)
> +static int ext2_cache_free_extents(ext2_filsys ext2_fs,
> + struct extent_io_tree *free_tree)
> {
> - blk_t block;
> -
> - if (!ext2fs_new_block(fs, goal, NULL, &block)) {
> - ext2fs_fast_mark_block_bitmap(fs->block_map, block);
> - *block_ret = block;
> - return 0;
> - }
> - return -ENOSPC;
> -}
> -
> -static int ext2_free_block(ext2_filsys fs, u64 block)
> -{
> - BUG_ON(block != (blk_t)block);
> - ext2fs_fast_unmark_block_bitmap(fs->block_map, block);
> - return 0;
> -}
> -
> -static int cache_free_extents(struct btrfs_root *root, ext2_filsys ext2_fs)
> -
> -{
> - int i, ret = 0;
> + int ret = 0;
> blk_t block;
> u64 bytenr;
> u64 blocksize = ext2_fs->blocksize;
> @@ -127,29 +108,68 @@ static int cache_free_extents(struct btrfs_root *root, ext2_filsys ext2_fs)
> if (ext2fs_fast_test_block_bitmap(ext2_fs->block_map, block))
> continue;
> bytenr = block * blocksize;
> - ret = set_extent_dirty(&root->fs_info->free_space_cache,
> - bytenr, bytenr + blocksize - 1, 0);
> + ret = set_extent_dirty(free_tree, bytenr,
> + bytenr + blocksize - 1, 0);
> BUG_ON(ret);
> }
>
> + return 0;
> +}
> +
> +/* mark btrfs-reserved blocks as used */
> +static void adjust_free_extents(ext2_filsys ext2_fs,
> + struct extent_io_tree *free_tree)
> +{
> + int i;
> + u64 bytenr;
> + u64 blocksize = ext2_fs->blocksize;
> +
> + clear_extent_dirty(free_tree, 0, BTRFS_SUPER_INFO_OFFSET - 1, 0);
> +
> for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
> bytenr = btrfs_sb_offset(i);
> bytenr &= ~((u64)STRIPE_LEN - 1);
> if (bytenr >= blocksize * ext2_fs->super->s_blocks_count)
> break;
> - clear_extent_dirty(&root->fs_info->free_space_cache, bytenr,
> - bytenr + STRIPE_LEN - 1, 0);
> + clear_extent_dirty(free_tree, bytenr, bytenr + STRIPE_LEN - 1,
> + 0);
> }
> +}
>
> - clear_extent_dirty(&root->fs_info->free_space_cache,
> - 0, BTRFS_SUPER_INFO_OFFSET - 1, 0);
> -
> +static int alloc_blocks(struct extent_io_tree *free_tree,
> + u64 *blocks, int num, u64 blocksize)
> +{
> + u64 start;
> + u64 end;
> + u64 last = 0;
> + u64 mask = blocksize - 1;
> + int ret;
> + while(num) {
> + ret = find_first_extent_bit(free_tree, last, &start, &end,
> + EXTENT_DIRTY);
> + if (ret)
> + goto fail;
> + last = end + 1;
> + if (start & mask)
> + start = (start & mask) + blocksize;
> + if (last - start < blocksize)
> + continue;
> + *blocks++ = start;
> + num--;
> + last = start + blocksize;
> + clear_extent_dirty(free_tree, start, last - 1, 0);
> + }
> return 0;
> +fail:
> + fprintf(stderr, "not enough free space\n");
> + return -ENOSPC;
> }
>
> static int custom_alloc_extent(struct btrfs_root *root, u64 num_bytes,
> u64 hint_byte, struct btrfs_key *ins)
> {
> + u64 blocksize = root->sectorsize;
> + u64 mask = blocksize - 1;
> u64 start;
> u64 end;
> u64 last = hint_byte;
> @@ -171,6 +191,8 @@ static int custom_alloc_extent(struct btrfs_root *root, u64 num_bytes,
>
> start = max(last, start);
> last = end + 1;
> + if (start & mask)
> + start = (start & mask) + blocksize;
> if (last - start < num_bytes)
> continue;
>
> @@ -1186,9 +1208,9 @@ static int create_image_file_range(struct btrfs_trans_handle *trans,
> struct btrfs_root *root, u64 objectid,
> struct btrfs_inode_item *inode,
> u64 start_byte, u64 end_byte,
> - ext2_filsys ext2_fs)
> + struct extent_io_tree *orig_free_tree)
> {
> - u32 blocksize = ext2_fs->blocksize;
> + u32 blocksize = root->sectorsize;
> u32 block = start_byte / blocksize;
> u32 last_block = (end_byte + blocksize - 1) / blocksize;
> int ret = 0;
> @@ -1205,7 +1227,8 @@ static int create_image_file_range(struct btrfs_trans_handle *trans,
> .errcode = 0,
> };
> for (; start_byte < end_byte; block++, start_byte += blocksize) {
> - if (!ext2fs_fast_test_block_bitmap(ext2_fs->block_map, block))
> + if (test_range_bit(orig_free_tree, start_byte,
> + start_byte + blocksize, EXTENT_DIRTY, 1))
> continue;
> ret = block_iterate_proc(NULL, block, block, &data);
> if (ret & BLOCK_ABORT) {
> @@ -1234,8 +1257,8 @@ fail:
> /*
> * Create the ext2fs image file.
> */
> -static int create_ext2_image(struct btrfs_root *root, ext2_filsys ext2_fs,
> - const char *name)
> +static int create_ext2_image(struct btrfs_root *root, const char *name,
> + struct extent_io_tree *orig_free_tree)
> {
> int ret;
> struct btrfs_key key;
> @@ -1348,7 +1371,7 @@ next:
> if (bytenr > last_byte) {
> ret = create_image_file_range(trans, root, objectid,
> &btrfs_inode, last_byte,
> - bytenr, ext2_fs);
> + bytenr, orig_free_tree);
> if (ret)
> goto fail;
> }
> @@ -1370,7 +1393,7 @@ next:
> if (total_bytes > last_byte) {
> ret = create_image_file_range(trans, root, objectid,
> &btrfs_inode, last_byte,
> - total_bytes, ext2_fs);
> + total_bytes, orig_free_tree);
> if (ret)
> goto fail;
> }
> @@ -2332,9 +2355,23 @@ err:
> return ret;
> }
>
> +static int copy_dirtiness(struct extent_io_tree *out,
> + struct extent_io_tree *in)
> +{
> + int ret;
> + u64 start, end, last = 0;
> + while (!find_first_extent_bit(in, last, &start, &end, EXTENT_DIRTY)) {
> + ret = set_extent_dirty(out, start, end, 0);
> + if (ret)
> + return ret;
> + last = end + 1;
> + }
> + return 0;
> +}
> +
> int do_convert(const char *devname, int datacsum, int packing, int noxattr)
> {
> - int i, fd, ret;
> + int fd, ret;
> u32 blocksize;
> u64 blocks[7];
> u64 total_bytes;
> @@ -2342,7 +2379,11 @@ int do_convert(const char *devname, int datacsum, int packing, int noxattr)
> ext2_filsys ext2_fs;
> struct btrfs_root *root;
> struct btrfs_root *ext2_root;
> + struct extent_io_tree free_tree;
> + struct extent_io_tree orig_free_tree;
>
> + extent_io_tree_init(&free_tree);
> + extent_io_tree_init(&orig_free_tree);
> ret = open_ext2fs(devname, &ext2_fs);
> if (ret) {
> fprintf(stderr, "unable to open the Ext2fs\n");
> @@ -2359,13 +2400,23 @@ int do_convert(const char *devname, int datacsum, int packing, int noxattr)
> fprintf(stderr, "filetype feature is missing\n");
> goto fail;
> }
> - for (i = 0; i < 7; i++) {
> - ret = ext2_alloc_block(ext2_fs, 0, blocks + i);
> - if (ret) {
> - fprintf(stderr, "not enough free space\n");
> - goto fail;
> - }
> - blocks[i] *= blocksize;
> + ret = ext2_cache_free_extents(ext2_fs, &orig_free_tree);
> + if (ret) {
> + fprintf(stderr, "error during cache_free_extents %d\n", ret);
> + goto fail;
> + }
> + /* preserve first 64KiB, just in case */
> + clear_extent_dirty(&orig_free_tree, 0, BTRFS_SUPER_INFO_OFFSET - 1, 0);
> +
> + ret = copy_dirtiness(&free_tree, &orig_free_tree);
> + if (ret) {
> + fprintf(stderr, "error during copy_dirtiness %d\n", ret);
> + goto fail;
> + }
> + adjust_free_extents(ext2_fs, &free_tree);
> + ret = alloc_blocks(&free_tree, blocks, 7, blocksize);
> + if (ret) {
> + goto fail;
> }
> super_bytenr = blocks[0];
> fd = open(devname, O_RDWR);
> @@ -2391,17 +2442,9 @@ int do_convert(const char *devname, int datacsum, int packing, int noxattr)
> fprintf(stderr, "unable to open ctree\n");
> goto fail;
> }
> - ret = cache_free_extents(root, ext2_fs);
> - if (ret) {
> - fprintf(stderr, "error during cache_free_extents %d\n", ret);
> - goto fail;
> - }
> + copy_dirtiness(&root->fs_info->free_space_cache, &free_tree);
> + extent_io_tree_cleanup(&free_tree);
> root->fs_info->extent_ops = &extent_ops;
> - /* recover block allocation bitmap */
> - for (i = 0; i < 7; i++) {
> - blocks[i] /= blocksize;
> - ext2_free_block(ext2_fs, blocks[i]);
> - }
> ret = init_btrfs(root);
> if (ret) {
> fprintf(stderr, "unable to setup the root tree\n");
> @@ -2419,11 +2462,12 @@ int do_convert(const char *devname, int datacsum, int packing, int noxattr)
> fprintf(stderr, "unable to create subvol\n");
> goto fail;
> }
> - ret = create_ext2_image(ext2_root, ext2_fs, "image");
> + ret = create_ext2_image(ext2_root, "image", &orig_free_tree);
extent_io_tree is not very space efficient. caching free space in
several places is not good. I prefer adding a function that checks
if a given block is used to the 'convert_fs' structure.
> if (ret) {
> fprintf(stderr, "error during create_ext2_image %d\n", ret);
> goto fail;
> }
> + extent_io_tree_cleanup(&orig_free_tree);
> printf("cleaning up system chunk.\n");
> ret = cleanup_sys_chunk(root, ext2_root);
> if (ret) {
> --
> 1.6.4.4
>
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