Re: [PATCH v3 2/2] ntdll: Use the F_PREALLOCATE fcntl(2) on Mac OS when posix_fallocate(2/3) isn't available.

[Huw Davies]

On Tue, Sep 14, 2021 at 04:57:42PM -0500, Chip Davis wrote:
> From: Charles Davis
> Signed-off-by: Chip Davis
>
> dlls/ntdll/unix/file.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
>
> diff --git a/dlls/ntdll/unix/file.c b/dlls/ntdll/unix/file.c
> index c92cbd1db4a..899cdc9868a 100644
> --- a/dlls/ntdll/unix/file.c
> +++ b/dlls/ntdll/unix/file.c
> @@ -4581,6 +4581,22 @@ NTSTATUS WINAPI NtSetInformationFile( HANDLE handle, IO_STATUS_BLOCK *io,
>                      if (err == EOPNOTSUPP) WARN( "posix_fallocate not supported on this filesystem\n" );
>                      else status = errno_to_status( err );
>                  }
> +#elif defined(F_PREALLOCATE)
> -
>            struct stat st;
> -
> -
>            if (fstat( fd, &st ) < 0)
> -
>                status = errno_to_status( errno );

There's already a call to fstat() in the outer block so this seems
unnecessary.
> -
>            else
> -
>            {
> -
>                struct fstore fst;
> -
> -
>                fst.fst_flags = F_ALLOCATECONTIG|F_ALLOCATEALL;
> -
>                fst.fst_posmode = F_PEOFPOSMODE;
> -
>                fst.fst_offset = 0;
> -
>                fst.fst_length = (off_t)info->ValidDataLength.QuadPart - st.st_blocks * 512;

Ignoring the potential for a race here, shouldn't you fetch the block
size from fstatfs() rather than hard-coding it?
> -
>                if (fcntl( fd, F_PREALLOCATE, &fst ) < 0)
> -
>                    status = errno_to_status( errno );
> -
>            }

Huw.