Re: [PATCH 3/5] btrfs: use the file extent tree infrastructure

[Josef Bacik <josef@toxicpanda.com>]

On 1/15/20 12:12 PM, Filipe Manana wrote:
> On Tue, Jan 7, 2020 at 7:43 PM Josef Bacik <josef@toxicpanda.com> wrote:
>>
>> We want to use this everywhere we modify the file extent items
>> permanently.  These include
>>
>> 1) Inserting new file extents for writes and prealloc extents.
>> 2) Truncating inode items.
>> 3) btrfs_cont_expand().
>> 4) Insert inline extents.
>> 5) Insert new extents from log replay.
>> 6) Insert a new extent for clone, as it could be past isize.
>>
>> We do not however call the clear helper for hole punching because it
>> simply swaps out an existing file extent for a hole, so there's
>> effectively no change as far as the i_size is concerned.
>>
>> Signed-off-by: Josef Bacik <josef@toxicpanda.com>
>> ---
>>   fs/btrfs/delayed-inode.c |  4 +++
>>   fs/btrfs/file.c          |  6 ++++
>>   fs/btrfs/inode.c         | 59 +++++++++++++++++++++++++++++++++++++++-
>>   fs/btrfs/tree-log.c      |  5 ++++
>>   4 files changed, 73 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
>> index d3e15e1d4a91..8b4dcf4f6b3e 100644
>> --- a/fs/btrfs/delayed-inode.c
>> +++ b/fs/btrfs/delayed-inode.c
>> @@ -1762,6 +1762,7 @@ int btrfs_fill_inode(struct inode *inode, u32 *rdev)
>>   {
>>          struct btrfs_delayed_node *delayed_node;
>>          struct btrfs_inode_item *inode_item;
>> +       struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
>>
>>          delayed_node = btrfs_get_delayed_node(BTRFS_I(inode));
>>          if (!delayed_node)
>> @@ -1779,6 +1780,9 @@ int btrfs_fill_inode(struct inode *inode, u32 *rdev)
>>          i_uid_write(inode, btrfs_stack_inode_uid(inode_item));
>>          i_gid_write(inode, btrfs_stack_inode_gid(inode_item));
>>          btrfs_i_size_write(BTRFS_I(inode), btrfs_stack_inode_size(inode_item));
>> +       btrfs_inode_set_file_extent_range(BTRFS_I(inode), 0,
>> +                                         round_up(i_size_read(inode),
>> +                                                  fs_info->sectorsize));
> 
> Why set it here when we have already done it at btrfs_read_locked_inode()?
> This seems duplicated.
> 

Because if btrfs_fill_inode() returns true it means we had a delayed inode in 
memory still and we skip the reading of the inode off of disk, so it's an either 
or case, not a duplicate.  Thanks,

Josef