On Wed, Mar 24, 2021 at 03:21:24PM +0100, Christoph Hellwig wrote:
> The i_cowextsize field is only used for v3 inodes, and the i_flushiter
> field is only used for v1/v2 inodes. Use a union to pack the inode a
> littler better after adding a few missing guards around their usage.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Yes, that's a nice compression opportunity.
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
--D
> ---
> fs/xfs/libxfs/xfs_inode_buf.c | 3 ++-
> fs/xfs/xfs_inode.c | 6 ++++--
> fs/xfs/xfs_inode.h | 7 +++++--
> fs/xfs/xfs_ioctl.c | 6 +++++-
> 4 files changed, 16 insertions(+), 6 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
> index d090274fb8a152..96db2649f6b2fe 100644
> --- a/fs/xfs/libxfs/xfs_inode_buf.c
> +++ b/fs/xfs/libxfs/xfs_inode_buf.c
> @@ -193,7 +193,8 @@ xfs_inode_from_disk(
> * inode. If the inode is unused, mode is zero and we shouldn't mess
> * with the uninitialized part of it.
> */
> - ip->i_flushiter = be16_to_cpu(from->di_flushiter);
> + if (!xfs_sb_version_has_v3inode(&ip->i_mount->m_sb))
> + ip->i_flushiter = be16_to_cpu(from->di_flushiter);
> inode->i_generation = be32_to_cpu(from->di_gen);
> inode->i_mode = be16_to_cpu(from->di_mode);
> if (!inode->i_mode)
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index e951ea48b3a276..b4b6fddccd1ca0 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -3459,8 +3459,10 @@ xfs_iflush(
> xfs_inode_to_disk(ip, dip, iip->ili_item.li_lsn);
>
> /* Wrap, we never let the log put out DI_MAX_FLUSH */
> - if (ip->i_flushiter == DI_MAX_FLUSH)
> - ip->i_flushiter = 0;
> + if (!xfs_sb_version_has_v3inode(&mp->m_sb)) {
> + if (ip->i_flushiter == DI_MAX_FLUSH)
> + ip->i_flushiter = 0;
> + }
>
> xfs_iflush_fork(ip, dip, iip, XFS_DATA_FORK);
> if (XFS_IFORK_Q(ip))
> diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
> index 6246ee8a4359ab..7ba0ffa50ede20 100644
> --- a/fs/xfs/xfs_inode.h
> +++ b/fs/xfs/xfs_inode.h
> @@ -58,8 +58,11 @@ typedef struct xfs_inode {
> xfs_rfsblock_t i_nblocks; /* # of direct & btree blocks */
> uint32_t i_projid; /* owner's project id */
> xfs_extlen_t i_extsize; /* basic/minimum extent size */
> - xfs_extlen_t i_cowextsize; /* basic cow extent size */
> - uint16_t i_flushiter; /* incremented on flush */
> + /* cowextsize is only used for v3 inodes, flushiter for v1/2 */
> + union {
> + xfs_extlen_t i_cowextsize; /* basic cow extent size */
> + uint16_t i_flushiter; /* incremented on flush */
> + };
>
> struct xfs_icdinode i_d; /* most of ondisk inode */
>
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index e45bce9b11082c..3405a5f5bacfda 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -1121,7 +1121,11 @@ xfs_fill_fsxattr(
>
> simple_fill_fsxattr(fa, xfs_ip2xflags(ip));
> fa->fsx_extsize = ip->i_extsize << ip->i_mount->m_sb.sb_blocklog;
> - fa->fsx_cowextsize = ip->i_cowextsize << ip->i_mount->m_sb.sb_blocklog;
> + if (xfs_sb_version_has_v3inode(&ip->i_mount->m_sb) &&
> + (ip->i_d.di_flags2 & XFS_DIFLAG2_COWEXTSIZE)) {
> + fa->fsx_cowextsize =
> + ip->i_cowextsize << ip->i_mount->m_sb.sb_blocklog;
> + }
> fa->fsx_projid = ip->i_projid;
> if (ifp && (ifp->if_flags & XFS_IFEXTENTS))
> fa->fsx_nextents = xfs_iext_count(ifp);
> --
> 2.30.1
>
