Re: [PATCH] f2fs: copy all valid xattr data includes the last zero

[Kinglong Mee <kinglongmee@gmail.com>]

On 3/20/2017 11:08, Jaegeuk Kim wrote:
> Hi Kinglong,
> 
> On 03/18, Kinglong Mee wrote:
>> It's better coping all valid xattr data includes the last zero. 
> 
> Why do we need this?
> 
> The size of txattr_addr would be larger than the space we need.
> 
> Thanks,
> 
>>
>> Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
>> ---
>>  fs/f2fs/xattr.c | 4 ++--
>>  fs/f2fs/xattr.h | 4 ++--
>>  2 files changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
>> index aff7619..41785c9 100644
>> --- a/fs/f2fs/xattr.c
>> +++ b/fs/f2fs/xattr.c
>> @@ -249,7 +249,7 @@ static int lookup_all_xattrs(struct inode *inode, struct page *ipage,
>>  	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>>  	void *cur_addr, *txattr_addr, *last_addr = NULL;
>>  	nid_t xnid = F2FS_I(inode)->i_xattr_nid;
>> -	unsigned int size = xnid ? VALID_XATTR_BLOCK_SIZE : 0;

Here maybe does not copy the last zero.

>> +	unsigned int size = xnid ? MAX_XATTR_BLOCK_SIZE : 0;
>>  	unsigned int inline_size = 0;
>>  	int err = 0;
>>  
>> @@ -328,7 +328,7 @@ static int read_all_xattrs(struct inode *inode, struct page *ipage,
>>  {
>>  	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>>  	struct f2fs_xattr_header *header;
>> -	size_t size = PAGE_SIZE, inline_size = 0;

Yes, it's larger.
It's for consistent with the above.

thanks,
Kinglong Mee

>> +	size_t size = MAX_XATTR_BLOCK_SIZE, inline_size = 0;
>>  	void *txattr_addr;
>>  	int err;
>>  
>> diff --git a/fs/f2fs/xattr.h b/fs/f2fs/xattr.h
>> index d5a9492..629c8ae 100644
>> --- a/fs/f2fs/xattr.h
>> +++ b/fs/f2fs/xattr.h
>> @@ -73,9 +73,9 @@ struct f2fs_xattr_entry {
>>  				!IS_XATTR_LAST_ENTRY(entry);\
>>  				entry = XATTR_NEXT_ENTRY(entry))
>>  #define MAX_XATTR_BLOCK_SIZE	(PAGE_SIZE - sizeof(struct node_footer))
>> -#define VALID_XATTR_BLOCK_SIZE	(MAX_XATTR_BLOCK_SIZE - sizeof(__u32))
>> +/* A __u32 is reserved for the last entry as zero */
>>  #define MIN_OFFSET(i)		XATTR_ALIGN(inline_xattr_size(i) +	\
>> -						VALID_XATTR_BLOCK_SIZE)
>> +				MAX_XATTR_BLOCK_SIZE - sizeof(__u32))
>>  
>>  #define MAX_VALUE_LEN(i)	(MIN_OFFSET(i) -			\
>>  				sizeof(struct f2fs_xattr_header) -	\
>> -- 
>> 2.9.3
> 

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