xfs: reduce the absurdly large log operation count

Back in the early days of reflink and rmap development I set the
transaction reservation sizes to be overly generous for rmap+reflink
filesystems, and a little under-generous for rmap-only filesystems.

Since we don't need *eight* transaction rolls to handle three new log
intent items, decrease the logcounts to what we actually need, and amend
the shadow reservation computation function to reflect what we used to
do so that the minimum log size doesn't change.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 19 insertions, 27 deletions

diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c
index 8e1d09e8cc9a..60be82cd491b 100644
--- a/fs/xfs/libxfs/xfs_trans_resv.c
+++ b/fs/xfs/libxfs/xfs_trans_resv.c
@@ -815,36 +815,18 @@ xfs_trans_resv_calc(
 	struct xfs_mount	*mp,
 	struct xfs_trans_resv	*resp)
 {
-	unsigned int		rmap_maxlevels = mp->m_rmap_maxlevels;
-
-	/*
-	 * In the early days of rmap+reflink, we always set the rmap maxlevels
-	 * to 9 even if the AG was small enough that it would never grow to
-	 * that height.  Transaction reservation sizes influence the minimum
-	 * log size calculation, which influences the size of the log that mkfs
-	 * creates.  Use the old value here to ensure that newly formatted
-	 * small filesystems will mount on older kernels.
-	 */
-	if (xfs_has_rmapbt(mp) && xfs_has_reflink(mp))
-		mp->m_rmap_maxlevels = XFS_OLD_REFLINK_RMAP_MAXLEVELS;
+	int			logcount_adj = 0;
 
 	/*
 	 * The following transactions are logged in physical format and
 	 * require a permanent reservation on space.
 	 */
 	resp->tr_write.tr_logres = xfs_calc_write_reservation(mp);
-	if (xfs_has_reflink(mp))
-		resp->tr_write.tr_logcount = XFS_WRITE_LOG_COUNT_REFLINK;
-	else
-		resp->tr_write.tr_logcount = XFS_WRITE_LOG_COUNT;
+	resp->tr_write.tr_logcount = XFS_WRITE_LOG_COUNT;
 	resp->tr_write.tr_logflags |= XFS_TRANS_PERM_LOG_RES;
 
 	resp->tr_itruncate.tr_logres = xfs_calc_itruncate_reservation(mp);
-	if (xfs_has_reflink(mp))
-		resp->tr_itruncate.tr_logcount =
-				XFS_ITRUNCATE_LOG_COUNT_REFLINK;
-	else
-		resp->tr_itruncate.tr_logcount = XFS_ITRUNCATE_LOG_COUNT;
+	resp->tr_itruncate.tr_logcount = XFS_ITRUNCATE_LOG_COUNT;
 	resp->tr_itruncate.tr_logflags |= XFS_TRANS_PERM_LOG_RES;
 
 	resp->tr_rename.tr_logres = xfs_calc_rename_reservation(mp);
@@ -901,10 +883,7 @@ xfs_trans_resv_calc(
 	resp->tr_growrtalloc.tr_logflags |= XFS_TRANS_PERM_LOG_RES;
 
 	resp->tr_qm_dqalloc.tr_logres = xfs_calc_qm_dqalloc_reservation(mp);
-	if (xfs_has_reflink(mp))
-		resp->tr_qm_dqalloc.tr_logcount = XFS_WRITE_LOG_COUNT_REFLINK;
-	else
-		resp->tr_qm_dqalloc.tr_logcount = XFS_WRITE_LOG_COUNT;
+	resp->tr_qm_dqalloc.tr_logcount = XFS_WRITE_LOG_COUNT;
 	resp->tr_qm_dqalloc.tr_logflags |= XFS_TRANS_PERM_LOG_RES;
 
 	/*
@@ -931,6 +910,19 @@ xfs_trans_resv_calc(
 	resp->tr_growrtzero.tr_logres = xfs_calc_growrtzero_reservation(mp);
 	resp->tr_growrtfree.tr_logres = xfs_calc_growrtfree_reservation(mp);
 
-	/* Put everything back the way it was.  This goes at the end. */
-	mp->m_rmap_maxlevels = rmap_maxlevels;
+	/*
+	 * Add one logcount for BUI items that appear with rmap or reflink,
+	 * one logcount for refcount intent items, and one logcount for rmap
+	 * intent items.
+	 */
+	if (xfs_has_reflink(mp) || xfs_has_rmapbt(mp))
+		logcount_adj++;
+	if (xfs_has_reflink(mp))
+		logcount_adj++;
+	if (xfs_has_rmapbt(mp))
+		logcount_adj++;
+
+	resp->tr_itruncate.tr_logcount += logcount_adj;
+	resp->tr_write.tr_logcount += logcount_adj;
+	resp->tr_qm_dqalloc.tr_logcount += logcount_adj;
 }