Re: [PATCH 1/9] common: extract rt extent size for _get_file_block_size

Christoph Hellwig
2020-10-28T21:52:03Z

On Tue, Oct 27, 2020 at 12:01:35PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
>
> _get_file_block_size is intended to return the size (in bytes) of the
> fundamental allocation unit for a file. This is required for remapping
> operations like fallocate and reflink, which can only operate on
> allocation units. Since the XFS realtime volume can be configure for
> allocation units larger than 1 fs block, we need to factor that in here.

Should this also cover the ext4 bigalloc clusters? Or do they not
matter for fallocate?

> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
> common/rc | 13 ++++++++++---
> common/xfs | 20 ++++++++++++++++++++
> 2 files changed, 30 insertions(+), 3 deletions(-)
>
>
> diff --git a/common/rc b/common/rc
> index 27a27ea3..41f93047 100644
> --- a/common/rc
> +++ b/common/rc
> @@ -3974,11 +3974,18 @@ _get_file_block_size()
> echo "Missing mount point argument for _get_file_block_size"
> exit 1
> fi
> - if [ "$FSTYP" = "ocfs2" ]; then
> +
> + case "$FSTYP" in
> + "ocfs2")
> stat -c '%o' $1
> - else
> + ;;
> + "xfs")
> + _xfs_get_file_block_size $1
> + ;;
> + *)
> _get_block_size $1
> - fi
> + ;;
> + esac
> }
>
> # Get the minimum block size of an fs.
> diff --git a/common/xfs b/common/xfs
> index 79dab058..3f5c14ba 100644
> --- a/common/xfs
> +++ b/common/xfs
> @@ -174,6 +174,26 @@ _scratch_mkfs_xfs()
> return $mkfs_status
> }
>
> +# Get the size of an allocation unit of a file. Normally this is just the
> +# block size of the file, but for realtime files, this is the realtime extent
> +# size.
> +_xfs_get_file_block_size()
> +{
> + local path="$1"
> +
> + if ! ($XFS_IO_PROG -c "stat -v" "$path" 2>&1 | egrep -q '(rt-inherit|realtime)'); then
> + _get_block_size "$path"
> + return
> + fi
> +
> + # Otherwise, call xfs_info until we find a mount point or the root.
> + path="$(readlink -m "$path")"
> + while ! $XFS_INFO_PROG "$path" &>/dev/null && [ "$path" != "/" ]; do
> + path="$(dirname "$path")"
> + done
> + $XFS_INFO_PROG "$path" | grep realtime | sed -e 's/^.*extsz=\([0-9]*\).*$/\1/g'
> +}
> +
> # xfs_check script is planned to be deprecated. But, we want to
> # be able to invoke "xfs_check" behavior in xfstests in order to
> # maintain the current verification levels.
>
---end quoted text---