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Btrfs: add hole punching

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This patch adds hole punching via fallocate.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
This commit is contained in:
Josef Bacik
2012-08-29 14:27:18 -04:00
committed by Chris Mason
parent 2671485d39
commit 2aaa665581
5 changed files with 355 additions and 13 deletions
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28
fs/btrfs/inode.c
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@@ -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;