[Ocfs2-devel] [PATCH 2/2] Ocfs2: Fix punching hole codes to correctly do CoW during cluster zeroing.

[Tao Ma <tao.ma@oracle.com>]

ack

Tristan Ye wrote:
> Based on the former patch of truncating optimization, bugfix for refcount on
> punching holes can be fairly easy and straightforward since most of work we
> should take into account for refcounting have been completed already in func
> ocfs2_remove_btree_range(), which is also being used by our truncating codes.
>
> The patch just did CoW for reflinks when a hole is being punched whose start
> and end offset were within one cluster, which means partial zeroing for a cluster
> will be performed soon.
>
> The patch has been tested fixing the following bug:
>
> http://oss.oracle.com/bugzilla/show_bug.cgi?id=1216
>
> Signed-off-by: Tristan Ye <tristan.ye@oracle.com>
> ---
>  fs/ocfs2/file.c |   30 +++++++++++++++++++++++++++---
>  1 files changed, 27 insertions(+), 3 deletions(-)
>
> diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
> index e0c9d1c..574fc9a 100644
> --- a/fs/ocfs2/file.c
> +++ b/fs/ocfs2/file.c
> @@ -1427,12 +1427,14 @@ static int ocfs2_remove_inode_range(struct inode *inode,
>  				    struct buffer_head *di_bh, u64 byte_start,
>  				    u64 byte_len)
>  {
> -	int ret = 0;
> +	int ret = 0, i, flags = 0;
>  	u32 trunc_start, trunc_len, cpos, phys_cpos, alloc_size;
>  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
>  	struct ocfs2_cached_dealloc_ctxt dealloc;
>  	struct address_space *mapping = inode->i_mapping;
>  	struct ocfs2_extent_tree et;
> +	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
> +	u64 refcount_loc = le64_to_cpu(di->i_refcount_loc);
>  
>  	ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode), di_bh);
>  	ocfs2_init_dealloc_ctxt(&dealloc);
> @@ -1458,6 +1460,27 @@ static int ocfs2_remove_inode_range(struct inode *inode,
>  		goto out;
>  	}
>  
> +	/*
> +	 * For reflinks, we may need to CoW 2 clusters which might be
> +	 * partially zero'd later, if hole's start and end offset were
> +	 * within one cluster(means is not exactly aligned to clustersize).
> +	 */
> +
> +	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_HAS_REFCOUNT_FL) {
> +
> +		ret = ocfs2_cow_file_pos(inode, di_bh, byte_start);
> +		if (ret) {
> +			mlog_errno(ret);
> +			goto out;
> +		}
> +
> +		ret = ocfs2_cow_file_pos(inode, di_bh, byte_start + byte_len);
> +		if (ret) {
> +			mlog_errno(ret);
> +			goto out;
> +		}
> +	}
> +
>  	trunc_start = ocfs2_clusters_for_bytes(osb->sb, byte_start);
>  	trunc_len = (byte_start + byte_len) >> osb->s_clustersize_bits;
>  	if (trunc_len >= trunc_start)
> @@ -1479,7 +1502,7 @@ static int ocfs2_remove_inode_range(struct inode *inode,
>  	cpos = trunc_start;
>  	while (trunc_len) {
>  		ret = ocfs2_get_clusters(inode, cpos, &phys_cpos,
> -					 &alloc_size, NULL);
> +					 &alloc_size, &flags);
>  		if (ret) {
>  			mlog_errno(ret);
>  			goto out;
> @@ -1492,7 +1515,8 @@ static int ocfs2_remove_inode_range(struct inode *inode,
>  		if (phys_cpos != 0) {
>  			ret = ocfs2_remove_btree_range(inode, &et, cpos,
>  						       phys_cpos, alloc_size,
> -						       &dealloc, 0, 0);
> +						       &dealloc, refcount_loc,
> +						       flags);
>  			if (ret) {
>  				mlog_errno(ret);
>  				goto out;
>