[Ocfs2-tools-devel] [PATCH 14/44] ocfs2: Integrate CoW in file write.

[Tao Ma]

Joel Becker wrote:
> On Mon, Dec 28, 2009 at 05:00:59PM +0800, Tao Ma wrote:
>> Call ocfs2_refcount_cow first to CoW refcounted clusters
>> in ocfs2_file_block_write.
>>
>> Signed-off-by: Tao Ma <tao.ma at oracle.com>
>> ---
>>  libocfs2/fileio.c |    9 +++++++++
>>  1 files changed, 9 insertions(+), 0 deletions(-)
>>
>> diff --git a/libocfs2/fileio.c b/libocfs2/fileio.c
>> index c4664ec..78ef5f5 100644
>> --- a/libocfs2/fileio.c
>> +++ b/libocfs2/fileio.c
>> @@ -33,6 +33,7 @@
>>  #include <inttypes.h>
>>  
>>  #include "ocfs2/ocfs2.h"
>> +#include "refcount.h"
>>  
>>  struct read_whole_context {
>>  	char		*buf;
>> @@ -325,6 +326,14 @@ static errcode_t ocfs2_file_block_write(ocfs2_cached_inode *ci,
>>  	if (v_blkno + wanted_blocks > num_blocks)
>>  		wanted_blocks = (uint32_t) (num_blocks - v_blkno);
>>  
>> +	cluster_begin = ocfs2_blocks_to_clusters(fs, v_blkno);
>> +	cluster_end = ocfs2_blocks_to_clusters(fs,
>> +					       v_blkno + wanted_blocks - 1);
>> +	n_clusters = cluster_end - cluster_begin + 1;
>> +	ret = ocfs2_refcount_cow(ci, cluster_begin, n_clusters, UINT_MAX);
>> +	if (ret)
>> +		return ret;
> 
> 	I'd say check for feature(REFCOUNT) and dyn_flags&REFCOUNT
> before calling ocfs2_refcount_cow().  Why do the NOOP work?
you are absolutely right.

Regards,
Tao