Re: [PATCH 27/46] xfs: remove the ->data_dot_entry_p and ->data_dotdot_entry_p methods

Darrick J. Wong
2019-11-08T00:51:31Z

On Thu, Nov 07, 2019 at 07:23:51PM +0100, Christoph Hellwig wrote:
> The only user of the ->data_dot_entry_p and ->data_dotdot_entry_p
> methods is the xfs_dir2_sf_to_block function that builds block format
> directorys from a short form directory. It already uses pointer
> arithmetics with a offset variable to do so for the real entries in
> the directory, so switch the generation of the . and .. entries to
> the same scheme, and clean up some of the later pointer arithmetics
> to use bp->b_addr directly as well and avoid some casts.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> fs/xfs/libxfs/xfs_da_format.c | 52 --------------------------------
> fs/xfs/libxfs/xfs_dir2.h | 4 ---
> fs/xfs/libxfs/xfs_dir2_block.c | 54 ++++++++++++++++------------------
> 3 files changed, 26 insertions(+), 84 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_da_format.c b/fs/xfs/libxfs/xfs_da_format.c
> index 7b783b11790d..711faff4aea2 100644
> --- a/fs/xfs/libxfs/xfs_da_format.c
> +++ b/fs/xfs/libxfs/xfs_da_format.c
> @@ -111,52 +111,6 @@ xfs_dir3_data_entry_tag_p(
> xfs_dir3_data_entsize(dep->namelen) - sizeof(__be16));
> }
>
> -/*
> - * location of . and .. in data space (always block 0)
> - */
> -static struct xfs_dir2_data_entry *
> -xfs_dir2_data_dot_entry_p(
> - struct xfs_dir2_data_hdr *hdr)
> -{
> - return (struct xfs_dir2_data_entry *)
> - ((char *)hdr + sizeof(struct xfs_dir2_data_hdr));
> -}
> -
> -static struct xfs_dir2_data_entry *
> -xfs_dir2_data_dotdot_entry_p(
> - struct xfs_dir2_data_hdr *hdr)
> -{
> - return (struct xfs_dir2_data_entry *)
> - ((char *)hdr + sizeof(struct xfs_dir2_data_hdr) +
> - XFS_DIR2_DATA_ENTSIZE(1));
> -}
> -
> -static struct xfs_dir2_data_entry *
> -xfs_dir2_ftype_data_dotdot_entry_p(
> - struct xfs_dir2_data_hdr *hdr)
> -{
> - return (struct xfs_dir2_data_entry *)
> - ((char *)hdr + sizeof(struct xfs_dir2_data_hdr) +
> - XFS_DIR3_DATA_ENTSIZE(1));
> -}
> -
> -static struct xfs_dir2_data_entry *
> -xfs_dir3_data_dot_entry_p(
> - struct xfs_dir2_data_hdr *hdr)
> -{
> - return (struct xfs_dir2_data_entry *)
> - ((char *)hdr + sizeof(struct xfs_dir3_data_hdr));
> -}
> -
> -static struct xfs_dir2_data_entry *
> -xfs_dir3_data_dotdot_entry_p(
> - struct xfs_dir2_data_hdr *hdr)
> -{
> - return (struct xfs_dir2_data_entry *)
> - ((char *)hdr + sizeof(struct xfs_dir3_data_hdr) +
> - XFS_DIR3_DATA_ENTSIZE(1));
> -}
> -
> static struct xfs_dir2_data_free *
> xfs_dir2_data_bestfree_p(struct xfs_dir2_data_hdr *hdr)
> {
> @@ -209,8 +163,6 @@ static const struct xfs_dir_ops xfs_dir2_ops = {
> XFS_DIR2_DATA_ENTSIZE(2),
> .data_entry_offset = sizeof(struct xfs_dir2_data_hdr),
>
> - .data_dot_entry_p = xfs_dir2_data_dot_entry_p,
> - .data_dotdot_entry_p = xfs_dir2_data_dotdot_entry_p,
> .data_entry_p = xfs_dir2_data_entry_p,
> .data_unused_p = xfs_dir2_data_unused_p,
> };
> @@ -227,8 +179,6 @@ static const struct xfs_dir_ops xfs_dir2_ftype_ops = {
> XFS_DIR3_DATA_ENTSIZE(2),
> .data_entry_offset = sizeof(struct xfs_dir2_data_hdr),
>
> - .data_dot_entry_p = xfs_dir2_data_dot_entry_p,
> - .data_dotdot_entry_p = xfs_dir2_ftype_data_dotdot_entry_p,
> .data_entry_p = xfs_dir2_data_entry_p,
> .data_unused_p = xfs_dir2_data_unused_p,
> };
> @@ -245,8 +195,6 @@ static const struct xfs_dir_ops xfs_dir3_ops = {
> XFS_DIR3_DATA_ENTSIZE(2),
> .data_entry_offset = sizeof(struct xfs_dir3_data_hdr),
>
> - .data_dot_entry_p = xfs_dir3_data_dot_entry_p,
> - .data_dotdot_entry_p = xfs_dir3_data_dotdot_entry_p,
> .data_entry_p = xfs_dir3_data_entry_p,
> .data_unused_p = xfs_dir3_data_unused_p,
> };
> diff --git a/fs/xfs/libxfs/xfs_dir2.h b/fs/xfs/libxfs/xfs_dir2.h
> index 8b937993263d..8bfcf4c1b9c4 100644
> --- a/fs/xfs/libxfs/xfs_dir2.h
> +++ b/fs/xfs/libxfs/xfs_dir2.h
> @@ -43,10 +43,6 @@ struct xfs_dir_ops {
> xfs_dir2_data_aoff_t data_first_offset;
> size_t data_entry_offset;
>
> - struct xfs_dir2_data_entry *
> - (*data_dot_entry_p)(struct xfs_dir2_data_hdr *hdr);
> - struct xfs_dir2_data_entry *
> - (*data_dotdot_entry_p)(struct xfs_dir2_data_hdr *hdr);
> struct xfs_dir2_data_entry *
> (*data_entry_p)(struct xfs_dir2_data_hdr *hdr);
> struct xfs_dir2_data_unused *
> diff --git a/fs/xfs/libxfs/xfs_dir2_block.c b/fs/xfs/libxfs/xfs_dir2_block.c
> index 6bc82a02b228..e7719356829d 100644
> --- a/fs/xfs/libxfs/xfs_dir2_block.c
> +++ b/fs/xfs/libxfs/xfs_dir2_block.c
> @@ -1038,39 +1038,35 @@ xfs_dir2_leaf_to_block(
> */
> int /* error */
> xfs_dir2_sf_to_block(
> - xfs_da_args_t *args) /* operation arguments */
> + struct xfs_da_args *args)
> {
> + struct xfs_trans *tp = args->trans;
> + struct xfs_inode *dp = args->dp;
> + struct xfs_mount *mp = dp->i_mount;
> + struct xfs_ifork *ifp = XFS_IFORK_PTR(dp, XFS_DATA_FORK);
> xfs_dir2_db_t blkno; /* dir-relative block # (0) */
> xfs_dir2_data_hdr_t *hdr; /* block header */
> xfs_dir2_leaf_entry_t *blp; /* block leaf entries */
> struct xfs_buf *bp; /* block buffer */
> xfs_dir2_block_tail_t *btp; /* block tail pointer */
> xfs_dir2_data_entry_t *dep; /* data entry pointer */
> - xfs_inode_t *dp; /* incore directory inode */
> int dummy; /* trash */
> xfs_dir2_data_unused_t *dup; /* unused entry pointer */
> int endoffset; /* end of data objects */
> int error; /* error return value */
> int i; /* index */
> - xfs_mount_t *mp; /* filesystem mount point */
> int needlog; /* need to log block header */
> int needscan; /* need to scan block freespc */
> int newoffset; /* offset from current entry */
> - int offset; /* target block offset */
> + unsigned int offset = dp->d_ops->data_entry_offset;
> xfs_dir2_sf_entry_t *sfep; /* sf entry pointer */
> xfs_dir2_sf_hdr_t *oldsfp; /* old shortform header */
> xfs_dir2_sf_hdr_t *sfp; /* shortform header */
> __be16 *tagp; /* end of data entry */
> - xfs_trans_t *tp; /* transaction pointer */
> struct xfs_name name;
> - struct xfs_ifork *ifp;
>
> trace_xfs_dir2_sf_to_block(args);
>
> - dp = args->dp;
> - tp = args->trans;
> - mp = dp->i_mount;
> - ifp = XFS_IFORK_PTR(dp, XFS_DATA_FORK);
> ASSERT(ifp->if_flags & XFS_IFINLINE);
> ASSERT(dp->i_d.di_size >= offsetof(struct xfs_dir2_sf_hdr, parent));
>
> @@ -1139,35 +1135,37 @@ xfs_dir2_sf_to_block(
> be16_to_cpu(dup->length), &needlog, &needscan);
> if (error)
> goto out_free;
> +
> /*
> * Create entry for .
> */
> - dep = dp->d_ops->data_dot_entry_p(hdr);
> + dep = bp->b_addr + offset;
> dep->inumber = cpu_to_be64(dp->i_ino);
> dep->namelen = 1;
> dep->name[0] = '.';
> dp->d_ops->data_put_ftype(dep, XFS_DIR3_FT_DIR);
> tagp = dp->d_ops->data_entry_tag_p(dep);
> - *tagp = cpu_to_be16((char *)dep - (char *)hdr);
> + *tagp = cpu_to_be16(offset);
> xfs_dir2_data_log_entry(args, bp, dep);
> blp[0].hashval = cpu_to_be32(xfs_dir_hash_dot);
> - blp[0].address = cpu_to_be32(xfs_dir2_byte_to_dataptr(
> - (char *)dep - (char *)hdr));
> + blp[0].address = cpu_to_be32(xfs_dir2_byte_to_dataptr(offset));
> + offset += dp->d_ops->data_entsize(dep->namelen);
> +
> /*
> * Create entry for ..
> */
> - dep = dp->d_ops->data_dotdot_entry_p(hdr);
> + dep = bp->b_addr + offset;

This is kind of a lot of open-coded void pointer arithmetic for my
tastes, but OTOH I guess there's not much of a way around that for
variable length records...

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> dep->inumber = cpu_to_be64(xfs_dir2_sf_get_parent_ino(sfp));
> dep->namelen = 2;
> dep->name[0] = dep->name[1] = '.';
> dp->d_ops->data_put_ftype(dep, XFS_DIR3_FT_DIR);
> tagp = dp->d_ops->data_entry_tag_p(dep);
> - *tagp = cpu_to_be16((char *)dep - (char *)hdr);
> + *tagp = cpu_to_be16(offset);
> xfs_dir2_data_log_entry(args, bp, dep);
> blp[1].hashval = cpu_to_be32(xfs_dir_hash_dotdot);
> - blp[1].address = cpu_to_be32(xfs_dir2_byte_to_dataptr(
> - (char *)dep - (char *)hdr));
> - offset = dp->d_ops->data_first_offset;
> + blp[1].address = cpu_to_be32(xfs_dir2_byte_to_dataptr(offset));
> + offset += dp->d_ops->data_entsize(dep->namelen);
> +
> /*
> * Loop over existing entries, stuff them in.
> */
> @@ -1176,6 +1174,7 @@ xfs_dir2_sf_to_block(
> sfep = NULL;
> else
> sfep = xfs_dir2_sf_firstentry(sfp);
> +
> /*
> * Need to preserve the existing offset values in the sf directory.
> * Insert holes (unused entries) where necessary.
> @@ -1192,11 +1191,10 @@ xfs_dir2_sf_to_block(
> * There should be a hole here, make one.
> */
> if (offset < newoffset) {
> - dup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
> + dup = bp->b_addr + offset;
> dup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
> dup->length = cpu_to_be16(newoffset - offset);
> - *xfs_dir2_data_unused_tag_p(dup) = cpu_to_be16(
> - ((char *)dup - (char *)hdr));
> + *xfs_dir2_data_unused_tag_p(dup) = cpu_to_be16(offset);
> xfs_dir2_data_log_unused(args, bp, dup);
> xfs_dir2_data_freeinsert(hdr,
> dp->d_ops->data_bestfree_p(hdr),
> @@ -1207,20 +1205,20 @@ xfs_dir2_sf_to_block(
> /*
> * Copy a real entry.
> */
> - dep = (xfs_dir2_data_entry_t *)((char *)hdr + newoffset);
> + dep = bp->b_addr + newoffset;
> dep->inumber = cpu_to_be64(xfs_dir2_sf_get_ino(mp, sfp, sfep));
> dep->namelen = sfep->namelen;
> dp->d_ops->data_put_ftype(dep, xfs_dir2_sf_get_ftype(mp, sfep));
> memcpy(dep->name, sfep->name, dep->namelen);
> tagp = dp->d_ops->data_entry_tag_p(dep);
> - *tagp = cpu_to_be16((char *)dep - (char *)hdr);
> + *tagp = cpu_to_be16(newoffset);
> xfs_dir2_data_log_entry(args, bp, dep);
> name.name = sfep->name;
> name.len = sfep->namelen;
> - blp[2 + i].hashval = cpu_to_be32(mp->m_dirnameops->
> - hashname(&name));
> - blp[2 + i].address = cpu_to_be32(xfs_dir2_byte_to_dataptr(
> - (char *)dep - (char *)hdr));
> + blp[2 + i].hashval =
> + cpu_to_be32(mp->m_dirnameops->hashname(&name));
> + blp[2 + i].address =
> + cpu_to_be32(xfs_dir2_byte_to_dataptr(newoffset));
> offset = (int)((char *)(tagp + 1) - (char *)hdr);
> if (++i == sfp->count)
> sfep = NULL;
> --
> 2.20.1
>