From 2aaa66558172b017f36bf38ae69372813dedee9d Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Wed, 29 Aug 2012 14:27:18 -0400 Subject: Btrfs: add hole punching This patch adds hole punching via fallocate. Thanks, Signed-off-by: Josef Bacik --- fs/btrfs/inode.c | 28 +++++++++++++++++++++------- 1 file changed, 21 insertions(+), 7 deletions(-) (limited to 'fs/btrfs/inode.c') diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index f0a4792492ed..8cb272c84089 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -3475,12 +3475,20 @@ error: } /* - * taken from block_truncate_page, but does cow as it zeros out - * any bytes left in the last page in the file. + * btrfs_truncate_page - read, zero a chunk and write a page + * @inode - inode that we're zeroing + * @from - the offset to start zeroing + * @len - the length to zero, 0 to zero the entire range respective to the + * offset + * @front - zero up to the offset instead of from the offset on + * + * This will find the page for the "from" offset and cow the page and zero the + * part we want to zero. This is used with truncate and hole punching. */ -static int btrfs_truncate_page(struct address_space *mapping, loff_t from) +int btrfs_truncate_page(struct inode *inode, loff_t from, loff_t len, + int front) { - struct inode *inode = mapping->host; + struct address_space *mapping = inode->i_mapping; struct btrfs_root *root = BTRFS_I(inode)->root; struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; struct btrfs_ordered_extent *ordered; @@ -3495,7 +3503,8 @@ static int btrfs_truncate_page(struct address_space *mapping, loff_t from) u64 page_start; u64 page_end; - if ((offset & (blocksize - 1)) == 0) + if ((offset & (blocksize - 1)) == 0 && + (!len || ((len & (blocksize - 1)) == 0))) goto out; ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE); if (ret) @@ -3555,8 +3564,13 @@ again: ret = 0; if (offset != PAGE_CACHE_SIZE) { + if (!len) + len = PAGE_CACHE_SIZE - offset; kaddr = kmap(page); - memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset); + if (front) + memset(kaddr, 0, offset); + else + memset(kaddr + offset, 0, len); flush_dcache_page(page); kunmap(page); } @@ -6796,7 +6810,7 @@ static int btrfs_truncate(struct inode *inode) u64 mask = root->sectorsize - 1; u64 min_size = btrfs_calc_trunc_metadata_size(root, 1); - ret = btrfs_truncate_page(inode->i_mapping, inode->i_size); + ret = btrfs_truncate_page(inode, inode->i_size, 0, 0); if (ret) return ret; -- cgit v1.2.3