Before we do real convert, we'd better read and build up used space
cache tree for later data/meta chunk layout calculation.
This patch will iterate all used blocks in ext2 filesystem and record it
into mkfs_cfg.used cache tree for later used.
This provides the basis for later btrfs-convert rework.
Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com>
---
btrfs-convert.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 77 insertions(+)
diff --git a/btrfs-convert.c b/btrfs-convert.c
index f66affd..3bee049 100644
--- a/btrfs-convert.c
+++ b/btrfs-convert.c
@@ -2286,6 +2286,77 @@ err:
return ret;
}
+static int add_one_used_block(ext2_filsys fs, char *bitmap,
+ unsigned long group_nr, struct cache_tree *used)
+{
+ unsigned long offset;
+ unsigned i;
+ int ret = 0;
+
+ offset = fs->super->s_first_data_block;
+ offset /= EXT2FS_CLUSTER_RATIO(fs);
+ offset += group_nr * fs->super->s_clusters_per_group;
+ for (i = 0; i < fs->super->s_clusters_per_group; i++) {
+ if (ext2fs_test_bit(i, bitmap)) {
+ u64 start;
+
+ start = (i + offset) * EXT2FS_CLUSTER_RATIO(fs);
+ start *= fs->blocksize;
+ ret = add_merge_cache_extent(used, start,
+ fs->blocksize);
+ if (ret < 0)
+ break;
+ }
+ }
+ return ret;
+}
+
+/*
+ * This function will iterate through all the ext2 block groups to fill used
+ * space tree.
+ * Which will later be used to build data chunk layout to ensure all ext2 used
+ * data will be covered by data chunk.
+ */
+static int read_ext2_used_space(ext2_filsys fs, struct cache_tree *used_tree)
+{
+ blk64_t blk_itr = EXT2FS_B2C(fs, fs->super->s_first_data_block);
+ char *block_bitmap = NULL;
+ unsigned long i;
+ int block_nbytes;
+ int ret = 0;
+
+ block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8;
+ ret = ext2fs_read_bitmaps(fs);
+ if (ret < 0)
+ return ret;
+ /* Shouldn't happen */
+ BUG_ON(!fs->block_map);
+
+ block_bitmap = malloc(block_nbytes);
+ if (!block_bitmap)
+ return -ENOMEM;
+
+ for (i = 0; i < fs->group_desc_count; i++) {
+ ret = ext2fs_get_block_bitmap_range2(fs->block_map, blk_itr,
+ block_nbytes * 8, block_bitmap);
+ if (ret) {
+ error("fail to get bitmap from ext2, %s",
+ strerror(-ret));
+ break;
+ }
+ ret = add_one_used_block(fs, block_bitmap, i, used_tree);
+ if (ret < 0) {
+ error("fail to build used space tree, %s",
+ strerror(-ret));
+ break;
+ }
+ blk_itr += fs->super->s_clusters_per_group;
+ }
+
+ free(block_bitmap);
+ return ret;
+}
+
static int do_convert(const char *devname, int datacsum, int packing, int
noxattr,
u32 nodesize, int copylabel, const char *fslabel, int progress,
u64 features)
@@ -2323,7 +2394,13 @@ static int do_convert(const char *devname, int datacsum,
int packing, int noxatt
if (btrfs_check_nodesize(nodesize, blocksize, features))
goto fail;
+ /* Build the used space tree first */
init_mkfs_config(&mkfs_cfg);
+ ret = read_ext2_used_space(ext2_fs, &mkfs_cfg.convert_used);
+ if (ret < 0) {
+ error("fail to read ext2 block bitmap\n");
+ goto fail;
+ }
blocks_per_node = nodesize / blocksize;
ret = -blocks_per_node;
--
2.6.2
--
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