Btrfs: add hole punching
This patch adds hole punching via fallocate. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index f0a4792..8cb272c 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3475,12 +3475,20 @@
}
/*
- * 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 @@
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 @@
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 @@
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;