From 48ddc6f44b5a167c00573b6012727d674e9c667a Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Tue, 10 Apr 2007 13:20:21 -0400 Subject: [PATCH] Btrfs: cow file extents before writing Signed-off-by: Chris Mason --- fs/btrfs/super.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 3e8bfb0e5d7e..91aa1b4c50af 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1020,7 +1020,7 @@ static int btrfs_get_block_lock(struct inode *inode, sector_t iblock, ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino, - iblock << inode->i_blkbits, 0); + iblock << inode->i_blkbits, 1); if (ret < 0) { err = ret; goto out; @@ -1040,9 +1040,25 @@ static int btrfs_get_block_lock(struct inode *inode, sector_t iblock, blocknr = btrfs_file_extent_disk_blocknr(item); blocknr += btrfs_file_extent_offset(item); - /* exact match found, use it */ + /* exact match found, use it, FIXME, deal with extents + * other than the page size + */ if (ret == 0) { err = 0; + BUG_ON(btrfs_file_extent_disk_num_blocks(item) != 1); + if (btrfs_file_extent_generation(item) != trans->transid) { + struct btrfs_key ins; + ret = btrfs_alloc_extent(trans, root, 1, + blocknr, (u64)-1, &ins); + BUG_ON(ret); + btrfs_set_file_extent_disk_blocknr(item, ins.objectid); + mark_buffer_dirty(path->nodes[0]); + ret = btrfs_free_extent(trans, root, + blocknr, 1, 0); + BUG_ON(ret); + blocknr = ins.objectid; + + } map_bh(result, inode->i_sb, blocknr); goto out; } -- 2.11.0