Re: [RFC PATCH V2 5/6] ext4: let ext4 maintian delayed extent trees

[Yongqiang Yang <xiaoqiangnk@gmail.com>]

On Thu, Sep 29, 2011 at 10:31 PM, Tao Ma <tm@tao.ma> wrote:
> On 09/29/2011 01:08 PM, Yongqiang Yang wrote:
>> This patch let ext4 maintain delayed extent trees.
>>
>> Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
>> ---
>>  fs/ext4/ext4.h     |    1 +
>>  fs/ext4/extents.c  |    2 ++
>>  fs/ext4/indirect.c |    3 +++
>>  fs/ext4/inode.c    |   28 ++++++++++++++++++++++++++--
>>  fs/ext4/super.c    |   12 +++++++++++-
>>  5 files changed, 43 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
>> index d3c6b97..177ec0a 100644
>> --- a/fs/ext4/ext4.h
>> +++ b/fs/ext4/ext4.h
>> @@ -519,6 +519,7 @@ struct ext4_new_group_data {
>>  #define EXT4_GET_BLOCKS_PUNCH_OUT_EXT                0x0020
>>       /* Don't normalize allocation size (used for fallocate) */
>>  #define EXT4_GET_BLOCKS_NO_NORMALIZE         0x0040
>> +#define EXT4_GET_BLOCKS_DEALLOC                      0x0080
>>
>>  /*
>>   * Flags used by ext4_free_blocks
>> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
>> index 9124cd2..bdbb984 100644
>> --- a/fs/ext4/extents.c
>> +++ b/fs/ext4/extents.c
>> @@ -3688,6 +3688,8 @@ void ext4_ext_truncate(struct inode *inode)
>>
>>       last_block = (inode->i_size + sb->s_blocksize - 1)
>>                       >> EXT4_BLOCK_SIZE_BITS(sb);
>> +     err = ext4_de_remove_space(inode, last_block,
>> +                                EXT_MAX_BLOCKS - last_block);
>>       err = ext4_ext_remove_space(inode, last_block);
>>
>>       /* In a multi-transaction truncate, we only make the final
>> diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
>> index 0962642..25cdb5b 100644
>> --- a/fs/ext4/indirect.c
>> +++ b/fs/ext4/indirect.c
>> @@ -22,6 +22,7 @@
>>
>>  #include <linux/module.h>
>>  #include "ext4_jbd2.h"
>> +#include "ext4_extents.h"
>>  #include "truncate.h"
>>
>>  #include <trace/events/ext4.h>
>> @@ -1383,6 +1384,8 @@ void ext4_ind_truncate(struct inode *inode)
>>       down_write(&ei->i_data_sem);
>>
>>       ext4_discard_preallocations(inode);
>> +     ext4_de_remove_space(inode, last_block,
>> +                          EXT_MAX_BLOCKS - last_block);
>>
>>       /*
>>        * The orphan list entry will now protect us from any crash which
>> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
>> index f86b149..0f9f108 100644
>> --- a/fs/ext4/inode.c
>> +++ b/fs/ext4/inode.c
>> @@ -442,7 +442,15 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
>>       up_read((&EXT4_I(inode)->i_data_sem));
>>
>>       if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
>> -             int ret = check_block_validity(inode, map);
>> +             int ret;
>> +             if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
>> +                     /* delayed alloc may be allocated by fallocate,
>> +                      * we need to handle delayed extent here.
>> +                      */
>> +                     down_write((&EXT4_I(inode)->i_data_sem));
>> +                     goto delayed_mapped;
>> +             }
>> +             ret = check_block_validity(inode, map);
> I am not quite sure of this. So do you mean when we write_begin the
> extent isn't allocated, while in the time of writepage, the extent is
> fallocted, right? If this is the case, where do we update the reserve_space?
> I mean in ext4_da_get_block_prep, we call ext4_da_reserve_space, and if
> there is no fallocate, we will call ext4_da_update_reserve_space in
> ext4_ext_handle_uninitialized_extents. So in your case, the 2nd
> ext4_da_update_reserve_space wouldn't be called. I am not sure whether
> there will be some problem or not.
Hi  Tao,

What if fallocated blocks have been allocated by direct I/O?  I placed
a BUG() here, it was indeed triggered by xfstests 127.

The comment is not clear, sorry for that.

Yongqiang.
>
> Thanks
> Tao
>>               if (ret != 0)
>>                       return ret;
>>       }
>> @@ -517,8 +525,18 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
>>                       (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE))
>>                       ext4_da_update_reserve_space(inode, retval, 1);
>>       }
>> -     if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
>> +     if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
>>               ext4_clear_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED);
>> +delayed_mapped:
>> +             if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
>> +                     int ret;
>> +                     /* delayed allocation blocks has been allocated */
>> +                     ret = ext4_de_remove_space(inode, map->m_lblk,
>> +                                                map->m_len);
>> +                     if (ret < 0)
>> +                             retval = ret;
>> +             }
>> +     }
>>
>>       up_write((&EXT4_I(inode)->i_data_sem));
>>       if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
>> @@ -1630,6 +1648,12 @@ static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
>>                       /* not enough space to reserve */
>>                       return ret;
>>
>> +             down_write((&EXT4_I(inode)->i_data_sem));
>> +             ret = ext4_de_add_space(inode, map.m_lblk, map.m_len);
>> +             up_write((&EXT4_I(inode)->i_data_sem));
>> +             if (ret)
>> +                     return ret;
>> +
>>               map_bh(bh, inode->i_sb, invalid_block);
>>               set_buffer_new(bh);
>>               set_buffer_delay(bh);
>> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
>> index 247fcdd..a248551 100644
>> --- a/fs/ext4/super.c
>> +++ b/fs/ext4/super.c
>> @@ -49,6 +49,7 @@
>>  #include "xattr.h"
>>  #include "acl.h"
>>  #include "mballoc.h"
>> +#include "ext4_extents.h"
>>
>>  #define CREATE_TRACE_POINTS
>>  #include <trace/events/ext4.h>
>> @@ -967,6 +968,7 @@ void ext4_clear_inode(struct inode *inode)
>>       end_writeback(inode);
>>       dquot_drop(inode);
>>       ext4_discard_preallocations(inode);
>> +     ext4_de_remove_space(inode, 0, EXT_MAX_BLOCKS);
>>       if (EXT4_I(inode)->jinode) {
>>               jbd2_journal_release_jbd_inode(EXT4_JOURNAL(inode),
>>                                              EXT4_I(inode)->jinode);
>> @@ -4976,9 +4978,14 @@ static int __init ext4_init_fs(void)
>>               init_waitqueue_head(&ext4__ioend_wq[i]);
>>       }
>>
>> -     err = ext4_init_pageio();
>> +     err = ext4_init_de();
>>       if (err)
>>               return err;
>> +
>> +     err = ext4_init_pageio();
>> +     if (err)
>> +             goto out8;
>> +
>>       err = ext4_init_system_zone();
>>       if (err)
>>               goto out7;
>> @@ -5030,6 +5037,9 @@ out6:
>>       ext4_exit_system_zone();
>>  out7:
>>       ext4_exit_pageio();
>> +out8:
>> +     ext4_exit_de();
>> +
>>       return err;
>>  }
>>
>
>



-- 
Best Wishes
Yongqiang Yang
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html