On 5/9/17 4:00 AM, Christoph Hellwig wrote:
> XFS_HSIZE is an extremly confusing way to calculate the size of handle_t.
> Given that handle_t always only had two sizes, and one of them isn't
> even covered by XFS_HSIZE to start with just remove the macro and use
> a constant sizeof expression.
>
> Note that XFS_HSIZE isn't used in xfsprogs, xfsdump or xfstests either.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Ok, so with this assignment a few lines before:
handle.ha_fid.fid_len = sizeof(xfs_fid_t) - sizeof(handle.ha_fid.fid_len);
(so: fid_len == size of (fid_pad + fid_gen + fid_ino))
and:
(((char *) &(handle).ha_fid.fid_pad - (char *) &(handle)) + (handle).ha_fid.fid_len)
|< -- size of ha_u + sizeof fid_len --> | |<-sizeof(pad+gen+ino)->|
this does indeed seem to come out to sizeof(xfs_handle_t).
Looks winning, minor comment below
> ---
> fs/xfs/libxfs/xfs_fs.h | 4 ----
> fs/xfs/xfs_ioctl.c | 3 +--
> 2 files changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
> index 095bdf049a3f..a9aa13e66046 100644
> --- a/fs/xfs/libxfs/xfs_fs.h
> +++ b/fs/xfs/libxfs/xfs_fs.h
> @@ -446,10 +446,6 @@ typedef struct xfs_handle {
> } xfs_handle_t;
> #define ha_fsid ha_u._ha_fsid
>
> -#define XFS_HSIZE(handle) (((char *) &(handle).ha_fid.fid_pad \
> - - (char *) &(handle)) \
> - + (handle).ha_fid.fid_len)
> -
> /*
> * Structure passed to XFS_IOC_SWAPEXT
> */
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 6190697603c9..f6af76975bc8 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -120,8 +120,7 @@ xfs_find_handle(
> handle.ha_fid.fid_pad = 0;
> handle.ha_fid.fid_gen = inode->i_generation;
> handle.ha_fid.fid_ino = ip->i_ino;
> -
> - hsize = XFS_HSIZE(handle);
> + hsize = sizeof(xfs_handle_t);
at this point, no need to have the hsize assignment in if { } as well as else { }, right?
-Eric
> }
>
> error = -EFAULT;
>
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