Re: [PATCH 3/4] xfs: combine xfs_rtmodify_summary and xfs_rtget_summary

Brian Foster
2014-08-22T13:19:58Z

On Thu, Aug 21, 2014 at 08:00:45PM -0500, Eric Sandeen wrote:
> xfs_rtmodify_summary and xfs_rtget_summary are
> almost identical; fold them into
> xfs_rtmodify_summary_int(), with wrappers for
> each of the original calls.
>
> The _int function modifies if a delta is passed,
> and returns a summary pointer if *sum is passed.
>
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---
>
> diff --git a/fs/xfs/libxfs/xfs_rtbitmap.c b/fs/xfs/libxfs/xfs_rtbitmap.c
> index f4dd697..50e3b93 100644
> --- a/fs/xfs/libxfs/xfs_rtbitmap.c
> +++ b/fs/xfs/libxfs/xfs_rtbitmap.c
> @@ -424,20 +424,24 @@ xfs_rtfind_forw(
> }
>
> /*
> - * Read and modify the summary information for a given extent size,
> + * Read and/or modify the summary information for a given extent size,
> * bitmap block combination.
> * Keeps track of a current summary block, so we don't keep reading
> * it from the buffer cache.
> + *
> + * Summary information is returned in *sum if specified.
> + * If no delta is specified, returns summary only.
> */
> int
> -xfs_rtmodify_summary(
> - xfs_mount_t *mp, /* file system mount point */
> +xfs_rtmodify_summary_int(
> + xfs_mount_t *mp, /* file system mount structure */
> xfs_trans_t *tp, /* transaction pointer */
> int log, /* log2 of extent size */
> xfs_rtblock_t bbno, /* bitmap block number */
> int delta, /* change to make to summary info */
> xfs_buf_t **rbpp, /* in/out: summary block buffer */
> - xfs_fsblock_t *rsb) /* in/out: summary block number */
> + xfs_fsblock_t *rsb, /* in/out: summary block number */
> + xfs_suminfo_t *sum) /* out: summary info for this block */
> {
> xfs_buf_t *bp; /* buffer for the summary block */
> int error; /* error value */
> @@ -480,15 +484,40 @@ xfs_rtmodify_summary(
> }
> }
> /*
> - * Point to the summary information, modify and log it.
> + * Point to the summary information, modify/log it, and/or copy it out.
> */
> sp = XFS_SUMPTR(mp, bp, so);
> - *sp += delta;
> - xfs_trans_log_buf(tp, bp, (uint)((char *)sp - (char *)bp->b_addr),
> - (uint)((char *)sp - (char *)bp->b_addr + sizeof(*sp) - 1));
> + if (delta) {
> + uint first = (uint)((char *)sp - (char *)bp->b_addr);
> +
> + *sp += delta;
> + xfs_trans_log_buf(tp, bp, first, first + sizeof(*sp) - 1);
> + }
> + if (sum) {
> + /*
> + * Drop the buffer if we're not asked to remember it.
> + */
> + if (!rbpp)
> + xfs_trans_brelse(tp, bp);

This introduces some potentially weird circumstances (e.g., acquire,
log, release of a buffer), but I think it's resolved by the next patch.

Reviewed-by: Brian Foster <bfoster@redhat.com>

> + *sum = *sp;
> + }
> return 0;
> }
>
> +int
> +xfs_rtmodify_summary(
> + xfs_mount_t *mp, /* file system mount structure */
> + xfs_trans_t *tp, /* transaction pointer */
> + int log, /* log2 of extent size */
> + xfs_rtblock_t bbno, /* bitmap block number */
> + int delta, /* change to make to summary info */
> + xfs_buf_t **rbpp, /* in/out: summary block buffer */
> + xfs_fsblock_t *rsb) /* in/out: summary block number */
> +{
> + return xfs_rtmodify_summary_int(mp, tp, log, bbno,
> + delta, rbpp, rsb, NULL);
> +}
> +
> /*
> * Set the given range of bitmap bits to the given value.
> * Do whatever I/O and logging is required.
> diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
> index 909e143..d1160cc 100644
> --- a/fs/xfs/xfs_rtalloc.c
> +++ b/fs/xfs/xfs_rtalloc.c
> @@ -46,7 +46,7 @@
> * Keeps track of a current summary block, so we don't keep reading
> * it from the buffer cache.
> */
> -STATIC int /* error */
> +int
> xfs_rtget_summary(
> xfs_mount_t *mp, /* file system mount structure */
> xfs_trans_t *tp, /* transaction pointer */
> @@ -56,60 +56,9 @@ xfs_rtget_summary(
> xfs_fsblock_t *rsb, /* in/out: summary block number */
> xfs_suminfo_t *sum) /* out: summary info for this block */
> {
> - xfs_buf_t *bp; /* buffer for summary block */
> - int error; /* error value */
> - xfs_fsblock_t sb; /* summary fsblock */
> - int so; /* index into the summary file */
> - xfs_suminfo_t *sp; /* pointer to returned data */
> -
> - /*
> - * Compute entry number in the summary file.
> - */
> - so = XFS_SUMOFFS(mp, log, bbno);
> - /*
> - * Compute the block number in the summary file.
> - */
> - sb = XFS_SUMOFFSTOBLOCK(mp, so);
> - /*
> - * If we have an old buffer, and the block number matches, use that.
> - */
> - if (rbpp && *rbpp && *rsb == sb)
> - bp = *rbpp;
> - /*
> - * Otherwise we have to get the buffer.
> - */
> - else {
> - /*
> - * If there was an old one, get rid of it first.
> - */
> - if (rbpp && *rbpp)
> - xfs_trans_brelse(tp, *rbpp);
> - error = xfs_rtbuf_get(mp, tp, sb, 1, &bp);
> - if (error) {
> - return error;
> - }
> - /*
> - * Remember this buffer and block for the next call.
> - */
> - if (rbpp) {
> - *rbpp = bp;
> - *rsb = sb;
> - }
> - }
> - /*
> - * Point to the summary information & copy it out.
> - */
> - sp = XFS_SUMPTR(mp, bp, so);
> - *sum = *sp;
> - /*
> - * Drop the buffer if we're not asked to remember it.
> - */
> - if (!rbpp)
> - xfs_trans_brelse(tp, bp);
> - return 0;
> + return xfs_rtmodify_summary_int(mp, tp, log, bbno, 0, rbpp, rsb, sum);
> }
>
> -
> /*
> * Return whether there are any free extents in the size range given
> * by low and high, for the bitmap block bbno.
> diff --git a/fs/xfs/xfs_rtalloc.h b/fs/xfs/xfs_rtalloc.h
> index c642795..76c0a4a 100644
> --- a/fs/xfs/xfs_rtalloc.h
> +++ b/fs/xfs/xfs_rtalloc.h
> @@ -111,6 +111,10 @@ int xfs_rtfind_forw(struct xfs_mount *mp, struct xfs_trans *tp,
> xfs_rtblock_t *rtblock);
> int xfs_rtmodify_range(struct xfs_mount *mp, struct xfs_trans *tp,
> xfs_rtblock_t start, xfs_extlen_t len, int val);
> +int xfs_rtmodify_summary_int(struct xfs_mount *mp, struct xfs_trans *tp,
> + int log, xfs_rtblock_t bbno, int delta,
> + xfs_buf_t **rbpp, xfs_fsblock_t *rsb,
> + xfs_suminfo_t *sum);
> int xfs_rtmodify_summary(struct xfs_mount *mp, struct xfs_trans *tp, int log,
> xfs_rtblock_t bbno, int delta, xfs_buf_t **rbpp,
> xfs_fsblock_t *rsb);
>
>
> _______________________________________________
> xfs mailing list
> xfs@oss.sgi.com
> http://oss.sgi.com/mailman/listinfo/xfs