From 31840ae1a6b433ca0e6a8d341756ff478bbf959e Mon Sep 17 00:00:00 2001 From: Zheng Yan Date: Tue, 23 Sep 2008 13:14:14 -0400 Subject: Btrfs: Full back reference support This patch makes the back reference system to explicit record the location of parent node for all types of extents. The location of parent node is placed into the offset field of backref key. Every time a tree block is balanced, the back references for the affected lower level extents are updated. Signed-off-by: Chris Mason --- fs/btrfs/file.c | 121 ++++++++++++++++++++++++++------------------------------ 1 file changed, 56 insertions(+), 65 deletions(-) (limited to 'fs/btrfs/file.c') diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 58b329ddb426..48a702d41c8c 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -524,6 +524,9 @@ int noinline btrfs_drop_extents(struct btrfs_trans_handle *trans, { u64 extent_end = 0; u64 search_start = start; + u64 leaf_start; + u64 root_gen; + u64 root_owner; struct extent_buffer *leaf; struct btrfs_file_extent_item *extent; struct btrfs_path *path; @@ -562,6 +565,9 @@ next_slot: bookend = 0; found_extent = 0; found_inline = 0; + leaf_start = 0; + root_gen = 0; + root_owner = 0; extent = NULL; leaf = path->nodes[0]; slot = path->slots[0]; @@ -628,27 +634,18 @@ next_slot: search_start = extent_end; if (end <= extent_end && start >= key.offset && found_inline) { *hint_byte = EXTENT_MAP_INLINE; - continue; + goto out; + } + + if (found_extent) { + read_extent_buffer(leaf, &old, (unsigned long)extent, + sizeof(old)); + root_gen = btrfs_header_generation(leaf); + root_owner = btrfs_header_owner(leaf); + leaf_start = leaf->start; } + if (end < extent_end && end >= key.offset) { - if (found_extent) { - u64 disk_bytenr = - btrfs_file_extent_disk_bytenr(leaf, extent); - u64 disk_num_bytes = - btrfs_file_extent_disk_num_bytes(leaf, - extent); - read_extent_buffer(leaf, &old, - (unsigned long)extent, - sizeof(old)); - if (disk_bytenr != 0) { - ret = btrfs_inc_extent_ref(trans, root, - disk_bytenr, disk_num_bytes, - root->root_key.objectid, - trans->transid, - key.objectid, end); - BUG_ON(ret); - } - } bookend = 1; if (found_inline && start <= key.offset) keep = 1; @@ -687,49 +684,12 @@ next_slot: } /* delete the entire extent */ if (!keep) { - u64 disk_bytenr = 0; - u64 disk_num_bytes = 0; - u64 extent_num_bytes = 0; - u64 root_gen; - u64 root_owner; - - root_gen = btrfs_header_generation(leaf); - root_owner = btrfs_header_owner(leaf); - if (found_extent) { - disk_bytenr = - btrfs_file_extent_disk_bytenr(leaf, - extent); - disk_num_bytes = - btrfs_file_extent_disk_num_bytes(leaf, - extent); - extent_num_bytes = - btrfs_file_extent_num_bytes(leaf, extent); - *hint_byte = - btrfs_file_extent_disk_bytenr(leaf, - extent); - } ret = btrfs_del_item(trans, root, path); /* TODO update progress marker and return */ BUG_ON(ret); - btrfs_release_path(root, path); extent = NULL; - if (found_extent && disk_bytenr != 0) { - dec_i_blocks(inode, extent_num_bytes); - ret = btrfs_free_extent(trans, root, - disk_bytenr, - disk_num_bytes, - root_owner, - root_gen, inode->i_ino, - key.offset, 0); - } - - BUG_ON(ret); - if (!bookend && search_start >= end) { - ret = 0; - goto out; - } - if (!bookend) - continue; + btrfs_release_path(root, path); + /* the extent will be freed later */ } if (bookend && found_inline && start <= key.offset) { u32 new_size; @@ -737,10 +697,13 @@ next_slot: extent_end - end); dec_i_blocks(inode, (extent_end - key.offset) - (extent_end - end)); - btrfs_truncate_item(trans, root, path, new_size, 0); + ret = btrfs_truncate_item(trans, root, path, + new_size, 0); + BUG_ON(ret); } /* create bookend, splitting the extent in two */ if (bookend && found_extent) { + u64 disk_bytenr; struct btrfs_key ins; ins.objectid = inode->i_ino; ins.offset = end; @@ -748,13 +711,9 @@ next_slot: btrfs_release_path(root, path); ret = btrfs_insert_empty_item(trans, root, path, &ins, sizeof(*extent)); + BUG_ON(ret); leaf = path->nodes[0]; - if (ret) { - btrfs_print_leaf(root, leaf); - printk("got %d on inserting %Lu %u %Lu start %Lu end %Lu found %Lu %Lu keep was %d\n", ret , ins.objectid, ins.type, ins.offset, start, end, key.offset, extent_end, keep); - } - BUG_ON(ret); extent = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_file_extent_item); write_extent_buffer(leaf, &old, @@ -770,11 +729,43 @@ next_slot: BTRFS_FILE_EXTENT_REG); btrfs_mark_buffer_dirty(path->nodes[0]); - if (le64_to_cpu(old.disk_bytenr) != 0) { + + disk_bytenr = le64_to_cpu(old.disk_bytenr); + if (disk_bytenr != 0) { + ret = btrfs_inc_extent_ref(trans, root, + disk_bytenr, + le64_to_cpu(old.disk_num_bytes), + leaf->start, + root->root_key.objectid, + trans->transid, + ins.objectid, ins.offset); + BUG_ON(ret); + } + btrfs_release_path(root, path); + if (disk_bytenr != 0) { inode->i_blocks += btrfs_file_extent_num_bytes(leaf, extent) >> 9; } + } + + if (found_extent && !keep) { + u64 disk_bytenr = le64_to_cpu(old.disk_bytenr); + + if (disk_bytenr != 0) { + dec_i_blocks(inode, le64_to_cpu(old.num_bytes)); + ret = btrfs_free_extent(trans, root, + disk_bytenr, + le64_to_cpu(old.disk_num_bytes), + leaf_start, root_owner, + root_gen, key.objectid, + key.offset, 0); + BUG_ON(ret); + *hint_byte = disk_bytenr; + } + } + + if (search_start >= end) { ret = 0; goto out; } -- cgit v1.2.3