Re: [PATCH 33/46] xfs: cleanup xfs_dir2_block_to_sf

Darrick J. Wong
2019-11-08T00:59:20Z

On Thu, Nov 07, 2019 at 07:23:57PM +0100, Christoph Hellwig wrote:
> Use an offset as the main means for iteration, and only do pointer
> arithmetics to find the data/unused entries.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Looks fairly straightforward...
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
> fs/xfs/libxfs/xfs_dir2_sf.c | 68 ++++++++++++++-----------------------
> 1 file changed, 25 insertions(+), 43 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_dir2_sf.c b/fs/xfs/libxfs/xfs_dir2_sf.c
> index 39a537c61b04..a1aed589dc8c 100644
> --- a/fs/xfs/libxfs/xfs_dir2_sf.c
> +++ b/fs/xfs/libxfs/xfs_dir2_sf.c
> @@ -255,64 +255,48 @@ xfs_dir2_block_sfsize(
> */
> int /* error */
> xfs_dir2_block_to_sf(
> - xfs_da_args_t *args, /* operation arguments */
> + struct xfs_da_args *args, /* operation arguments */
> struct xfs_buf *bp,
> int size, /* shortform directory size */
> - xfs_dir2_sf_hdr_t *sfhp) /* shortform directory hdr */
> + struct xfs_dir2_sf_hdr *sfhp) /* shortform directory hdr */
> {
> - xfs_dir2_data_hdr_t *hdr; /* block header */
> - xfs_dir2_data_entry_t *dep; /* data entry pointer */
> - xfs_inode_t *dp; /* incore directory inode */
> - xfs_dir2_data_unused_t *dup; /* unused data pointer */
> - char *endptr; /* end of data entries */
> + struct xfs_inode *dp = args->dp;
> + struct xfs_mount *mp = dp->i_mount;
> int error; /* error return value */
> int logflags; /* inode logging flags */
> - xfs_mount_t *mp; /* filesystem mount point */
> - char *ptr; /* current data pointer */
> - xfs_dir2_sf_entry_t *sfep; /* shortform entry */
> - xfs_dir2_sf_hdr_t *sfp; /* shortform directory header */
> - xfs_dir2_sf_hdr_t *dst; /* temporary data buffer */
> + struct xfs_dir2_sf_entry *sfep; /* shortform entry */
> + struct xfs_dir2_sf_hdr *sfp; /* shortform directory header */
> + unsigned int offset = dp->d_ops->data_entry_offset;
> + unsigned int end;
>
> trace_xfs_dir2_block_to_sf(args);
>
> - dp = args->dp;
> - mp = dp->i_mount;
> -
> /*
> - * allocate a temporary destination buffer the size of the inode
> - * to format the data into. Once we have formatted the data, we
> - * can free the block and copy the formatted data into the inode literal
> - * area.
> + * Allocate a temporary destination buffer the size of the inode to
> + * format the data into. Once we have formatted the data, we can free
> + * the block and copy the formatted data into the inode literal area.
> */
> - dst = kmem_alloc(mp->m_sb.sb_inodesize, 0);
> - hdr = bp->b_addr;
> -
> - /*
> - * Copy the header into the newly allocate local space.
> - */
> - sfp = (xfs_dir2_sf_hdr_t *)dst;
> + sfp = kmem_alloc(mp->m_sb.sb_inodesize, 0);
> memcpy(sfp, sfhp, xfs_dir2_sf_hdr_size(sfhp->i8count));
>
> /*
> - * Set up to loop over the block's entries.
> + * Loop over the active and unused entries. Stop when we reach the
> + * leaf/tail portion of the block.
> */
> - ptr = (char *)dp->d_ops->data_entry_p(hdr);
> - endptr = xfs_dir3_data_endp(args->geo, hdr);
> + end = xfs_dir3_data_endp(args->geo, bp->b_addr) - bp->b_addr;
> sfep = xfs_dir2_sf_firstentry(sfp);
> - /*
> - * Loop over the active and unused entries.
> - * Stop when we reach the leaf/tail portion of the block.
> - */
> - while (ptr < endptr) {
> + while (offset < end) {
> + struct xfs_dir2_data_unused *dup = bp->b_addr + offset;
> + struct xfs_dir2_data_entry *dep = bp->b_addr + offset;
> +
> /*
> * If it's unused, just skip over it.
> */
> - dup = (xfs_dir2_data_unused_t *)ptr;
> if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
> - ptr += be16_to_cpu(dup->length);
> + offset += be16_to_cpu(dup->length);
> continue;
> }
> - dep = (xfs_dir2_data_entry_t *)ptr;
> +
> /*
> * Skip .
> */
> @@ -330,9 +314,7 @@ xfs_dir2_block_to_sf(
> */
> else {
> sfep->namelen = dep->namelen;
> - xfs_dir2_sf_put_offset(sfep,
> - (xfs_dir2_data_aoff_t)
> - ((char *)dep - (char *)hdr));
> + xfs_dir2_sf_put_offset(sfep, offset);
> memcpy(sfep->name, dep->name, dep->namelen);
> xfs_dir2_sf_put_ino(mp, sfp, sfep,
> be64_to_cpu(dep->inumber));
> @@ -341,7 +323,7 @@ xfs_dir2_block_to_sf(
>
> sfep = xfs_dir2_sf_nextentry(mp, sfp, sfep);
> }
> - ptr += dp->d_ops->data_entsize(dep->namelen);
> + offset += dp->d_ops->data_entsize(dep->namelen);
> }
> ASSERT((char *)sfep - (char *)sfp == size);
>
> @@ -360,7 +342,7 @@ xfs_dir2_block_to_sf(
> * Convert the inode to local format and copy the data in.
> */
> ASSERT(dp->i_df.if_bytes == 0);
> - xfs_init_local_fork(dp, XFS_DATA_FORK, dst, size);
> + xfs_init_local_fork(dp, XFS_DATA_FORK, sfp, size);
> dp->i_d.di_format = XFS_DINODE_FMT_LOCAL;
> dp->i_d.di_size = size;
>
> @@ -368,7 +350,7 @@ xfs_dir2_block_to_sf(
> xfs_dir2_sf_check(args);
> out:
> xfs_trans_log_inode(args->trans, dp, logflags);
> - kmem_free(dst);
> + kmem_free(sfp);
> return error;
> }
>
> --
> 2.20.1
>