xfs: refactor xfs_rtsummary_blockcount

Make xfs_rtsummary_blockcount take all the required information from
the mount structure and return the number of summary levels from it
as well.  This cleans up many of the callers and prepares for making the
rtsummary files per-rtgroup where they need to look at different value.

This means we recalculate some values in some callers, but as all these
calculations are outside the fast path and cheap, which seems like a
price worth paying.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Darrick J. Wong <[email protected]>
Signed-off-by: Darrick J. Wong <[email protected]>

Author: Christoph Hellwig

fs/xfs/libxfs/xfs_rtbitmap.c

@@ -20,6 +20,7 @@
 #include "xfs_error.h"
 #include "xfs_rtbitmap.h"
 #include "xfs_health.h"
+#include "xfs_sb.h"
 
 /*
  * Realtime allocator bitmap functions shared with userspace.
@@ -1166,16 +1167,20 @@ xfs_rtbitmap_blockcount(
 	return xfs_rtbitmap_blockcount_len(mp, mp->m_sb.sb_rextents);
 }
 
-/* Compute the number of rtsummary blocks needed to track the given rt space. */
+/*
+ * Compute the geometry of the rtsummary file needed to track the given rt
+ * space.
+ */
 xfs_filblks_t
 xfs_rtsummary_blockcount(
 	struct xfs_mount	*mp,
-	unsigned int		rsumlevels,
-	xfs_extlen_t		rbmblocks)
+	unsigned int		*rsumlevels)
 {
 	unsigned long long	rsumwords;
 
-	rsumwords = (unsigned long long)rsumlevels * rbmblocks;
+	*rsumlevels = xfs_compute_rextslog(mp->m_sb.sb_rextents) + 1;
+
+	rsumwords = xfs_rtbitmap_blockcount(mp) * (*rsumlevels);
 	return XFS_B_TO_FSB(mp, rsumwords << XFS_WORDLOG);
 }
 

fs/xfs/libxfs/xfs_rtbitmap.h

@@ -311,7 +311,7 @@ xfs_filblks_t xfs_rtbitmap_blockcount(struct xfs_mount *mp);
 xfs_filblks_t xfs_rtbitmap_blockcount_len(struct xfs_mount *mp,
 		xfs_rtbxlen_t rtextents);
 xfs_filblks_t xfs_rtsummary_blockcount(struct xfs_mount *mp,
-		unsigned int rsumlevels, xfs_extlen_t rbmblocks);
+		unsigned int *rsumlevels);
 
 int xfs_rtfile_initialize_blocks(struct xfs_rtgroup *rtg,
 		enum xfs_rtg_inodes type, xfs_fileoff_t offset_fsb,
@@ -342,7 +342,6 @@ xfs_rtbitmap_blockcount_len(struct xfs_mount *mp, xfs_rtbxlen_t rtextents)
 	/* shut up gcc */
 	return 0;
 }
-# define xfs_rtsummary_blockcount(mp, l, b)		(0)
 #endif /* CONFIG_XFS_RT */
 
 #endif /* __XFS_RTBITMAP_H__ */

fs/xfs/scrub/rtsummary.c

@@ -102,14 +102,10 @@ xchk_setup_rtsummary(
 	 */
 	xchk_rtgroup_lock(&sc->sr, XFS_RTGLOCK_BITMAP);
 	if (mp->m_sb.sb_rblocks) {
-		int		rextslog;
-
 		rts->rextents = xfs_rtb_to_rtx(mp, mp->m_sb.sb_rblocks);
-		rextslog = xfs_compute_rextslog(mp->m_sb.sb_rextents);
-		rts->rsumlevels = rextslog + 1;
 		rts->rbmblocks = xfs_rtbitmap_blockcount(mp);
-		rts->rsumblocks = xfs_rtsummary_blockcount(mp, rts->rsumlevels,
-				rts->rbmblocks);
+		rts->rsumblocks =
+			xfs_rtsummary_blockcount(mp, &rts->rsumlevels);
 	}
 
 	return 0;

fs/xfs/xfs_mount.h

@@ -173,7 +173,7 @@ typedef struct xfs_mount {
 	uint			m_allocsize_blocks; /* min write size blocks */
 	int			m_logbufs;	/* number of log buffers */
 	int			m_logbsize;	/* size of each log buffer */
-	uint			m_rsumlevels;	/* rt summary levels */
+	unsigned int		m_rsumlevels;	/* rt summary levels */
 	xfs_filblks_t		m_rsumblocks;	/* size of rt summary, FSBs */
 	uint32_t		m_rgblocks;	/* size of rtgroup in rtblocks */
 	int			m_fixedfsid[2];	/* unchanged for life of FS */

fs/xfs/xfs_rtalloc.c

@@ -751,9 +751,7 @@ xfs_growfs_rt_alloc_fake_mount(
 	nmp->m_sb.sb_rextents = xfs_rtb_to_rtx(nmp, nmp->m_sb.sb_rblocks);
 	nmp->m_sb.sb_rbmblocks = xfs_rtbitmap_blockcount(nmp);
 	nmp->m_sb.sb_rextslog = xfs_compute_rextslog(nmp->m_sb.sb_rextents);
-	nmp->m_rsumlevels = nmp->m_sb.sb_rextslog + 1;
-	nmp->m_rsumblocks = xfs_rtsummary_blockcount(nmp, nmp->m_rsumlevels,
-			nmp->m_sb.sb_rbmblocks);
+	nmp->m_rsumblocks = xfs_rtsummary_blockcount(nmp, &nmp->m_rsumlevels);
 
 	if (rblocks > 0)
 		nmp->m_features |= XFS_FEAT_REALTIME;
@@ -1138,21 +1136,18 @@ xfs_rtmount_init(
 	struct xfs_mount	*mp)	/* file system mount structure */
 {
 	struct xfs_buf		*bp;	/* buffer for last block of subvolume */
-	struct xfs_sb		*sbp;	/* filesystem superblock copy in mount */
 	xfs_daddr_t		d;	/* address of last block of subvolume */
 	int			error;
 
-	sbp = &mp->m_sb;
-	if (sbp->sb_rblocks == 0)
+	if (mp->m_sb.sb_rblocks == 0)
 		return 0;
 	if (mp->m_rtdev_targp == NULL) {
 		xfs_warn(mp,
 	"Filesystem has a realtime volume, use rtdev=device option");
 		return -ENODEV;
 	}
-	mp->m_rsumlevels = sbp->sb_rextslog + 1;
-	mp->m_rsumblocks = xfs_rtsummary_blockcount(mp, mp->m_rsumlevels,
-			mp->m_sb.sb_rbmblocks);
+
+	mp->m_rsumblocks = xfs_rtsummary_blockcount(mp, &mp->m_rsumlevels);
 
 	/*
 	 * Check that the realtime section is an ok size.