Hi Xiang,
On 2019/7/16 15:19, Gao Xiang wrote:
> Hi Chao,
>
> On 2019/7/16 15:05, Chao Yu wrote:
>> Add erofs_bmap() to support FIBMAP ioctl on flatmode inode.
>>
>> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
>> ---
>> drivers/staging/erofs/data.c | 29 +++++++++++++++++++++++++++++
>> 1 file changed, 29 insertions(+)
>>
>> diff --git a/drivers/staging/erofs/data.c b/drivers/staging/erofs/data.c
>> index fbce71403d87..03da57f04347 100644
>> --- a/drivers/staging/erofs/data.c
>> +++ b/drivers/staging/erofs/data.c
>> @@ -308,9 +308,38 @@ static int erofs_raw_access_readpages(struct file *filp,
>> return iomap_readpages(mapping, pages, nr_pages, &erofs_iomap_ops);
>> }
>>
>> +static int erofs_get_block(struct inode *inode, sector_t iblock,
>> + struct buffer_head *bh, int create)
>> +{
>> + struct erofs_map_blocks map = {
>> + .m_la = iblock << 9,
>> + };
>> + int err;
>> +
>> + err = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);
>> + if (err)
>> + return err;
>> +
>> + if (map.m_flags & EROFS_MAP_MAPPED)
>> + bh->b_blocknr = erofs_blknr(map.m_pa);
>> +
>> + return err;
>> +}
>> +
>> +static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
>> +{
>> + struct inode *inode = mapping->host;
>> +
>> + if (is_inode_flat_inline(inode))
>> + return 0;
>
> could we support flat_inline as well? some difficulty on this?
I think we can support partial of this on inline inode, e.g.:
[0, 4k] mapped
[4k, 5k] inline
We can find and return the physical block address for first block, but for last
block locating in metadata, we should just return 0 (0 indicate bmap has failed
to get mapped block address).
Thanks,
> (I have no idea return 0 is suitable for us since we have tail-end packing...)
>
> Thanks,
> Gao Xiang
>
>> +
>> + return generic_block_bmap(mapping, block, erofs_get_block);
>> +}
>> +
>> /* for uncompressed (aligned) files and raw access for other files */
>> const struct address_space_operations erofs_raw_access_aops = {
>> .readpage = erofs_raw_access_readpage,
>> .readpages = erofs_raw_access_readpages,
>> + .bmap = erofs_bmap,
>> };
>>
>>
> .
>
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