From f578d4bd7e141dd03ca7e8695c1cc118c326e69e Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Thu, 25 Oct 2007 15:42:56 -0400 Subject: [PATCH] Btrfs: Optimize csum insertion to create larger items when possible This reduces the number of calls to btrfs_extend_item and greatly lowers the cpu usage while writing large files. Signed-off-by: Chris Mason --- fs/btrfs/ctree.h | 1 + fs/btrfs/file-item.c | 37 ++++++++++++++++++++++++++++++++++++- fs/btrfs/inode.c | 2 +- 3 files changed, 38 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 1d2b54150075..70e143b13577 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -991,6 +991,7 @@ int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans, u64 bytenr, int mod); int btrfs_csum_file_block(struct btrfs_trans_handle *trans, struct btrfs_root *root, + struct inode *inode, u64 objectid, u64 offset, char *data, size_t len); struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans, diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c index 10a4c7408600..482a2b615327 100644 --- a/fs/btrfs/file-item.c +++ b/fs/btrfs/file-item.c @@ -133,17 +133,22 @@ int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans, int btrfs_csum_file_block(struct btrfs_trans_handle *trans, struct btrfs_root *root, + struct inode *inode, u64 objectid, u64 offset, char *data, size_t len) { int ret; struct btrfs_key file_key; struct btrfs_key found_key; + u64 next_offset = (u64)-1; + int found_next = 0; struct btrfs_path *path; struct btrfs_csum_item *item; struct extent_buffer *leaf = NULL; u64 csum_offset; u32 csum_result = ~(u32)0; + u32 nritems; + u32 ins_size; path = btrfs_alloc_path(); BUG_ON(!path); @@ -168,7 +173,27 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans, goto insert; } } else { + int slot = path->slots[0] + 1; /* we didn't find a csum item, insert one */ + nritems = btrfs_header_nritems(path->nodes[0]); + if (path->slots[0] >= nritems - 1) { + ret = btrfs_next_leaf(root, path); + if (ret == 1) { + found_next = 1; + } else if (ret == 0) { + slot = 0; + } else { + goto insert; + } + } + btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot); + if (found_key.objectid != objectid || + found_key.type != BTRFS_CSUM_ITEM_KEY) { + found_next = 1; + goto insert; + } + next_offset = found_key.offset; + found_next = 1; goto insert; } @@ -211,8 +236,18 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans, insert: btrfs_release_path(root, path); csum_offset = 0; + if (found_next) { + u64 tmp = min((u64)i_size_read(inode), next_offset); + tmp -= offset + root->sectorsize - 1; + tmp >>= root->fs_info->sb->s_blocksize_bits; + tmp = max((u64)1, tmp); + tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root)); + ins_size = BTRFS_CRC32_SIZE * tmp; + } else { + ins_size = BTRFS_CRC32_SIZE; + } ret = btrfs_insert_empty_item(trans, root, path, &file_key, - BTRFS_CRC32_SIZE); + ins_size); if (ret < 0) goto fail; if (ret != 0) { diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 02d802cdd59b..7efc0470abf1 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -118,7 +118,7 @@ int btrfs_writepage_io_hook(struct page *page, u64 start, u64 end) trans = btrfs_start_transaction(root, 1); btrfs_set_trans_block_group(trans, inode); kaddr = kmap(page); - btrfs_csum_file_block(trans, root, inode->i_ino, + btrfs_csum_file_block(trans, root, inode, inode->i_ino, start, kaddr + offset, end - start + 1); kunmap(page); ret = btrfs_end_transaction(trans, root); -- 2.34.1