xfs: rename agfl perag res type to rmapbt

The AGFL perag reservation type accounts all allocations that feed
into (or are released from) the allocation group free list (agfl).
The purpose of the reservation is to support worst case conditions
for the reverse mapping btree (rmapbt). As such, the agfl
reservation usage accounting only considers rmapbt usage when the
in-core counters are initialized at mount time.

This implementation inconsistency leads to divergence of the in-core
and on-disk usage accounting over time. In preparation to resolve
this inconsistency and adjust the AGFL reservation into an rmapbt
specific reservation, rename the AGFL reservation type and
associated accounting fields to something more rmapbt-specific. Also
fix up a couple tracepoints that incorrectly use the AGFL
reservation type to pass the agfl state of the associated extent
where the raw reservation type is expected.

Note that this patch does not change perag reservation behavior.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

1 files changed, 18 insertions, 17 deletions

diff --git a/fs/xfs/libxfs/xfs_ag_resv.c b/fs/xfs/libxfs/xfs_ag_resv.c
index 2291f4224e24..0ca2e680034a 100644
--- a/fs/xfs/libxfs/xfs_ag_resv.c
+++ b/fs/xfs/libxfs/xfs_ag_resv.c
@@ -95,13 +95,13 @@ xfs_ag_resv_critical(
 
 	switch (type) {
 	case XFS_AG_RESV_METADATA:
-		avail = pag->pagf_freeblks - pag->pag_agfl_resv.ar_reserved;
+		avail = pag->pagf_freeblks - pag->pag_rmapbt_resv.ar_reserved;
 		orig = pag->pag_meta_resv.ar_asked;
 		break;
-	case XFS_AG_RESV_AGFL:
+	case XFS_AG_RESV_RMAPBT:
 		avail = pag->pagf_freeblks + pag->pagf_flcount -
 			pag->pag_meta_resv.ar_reserved;
-		orig = pag->pag_agfl_resv.ar_asked;
+		orig = pag->pag_rmapbt_resv.ar_asked;
 		break;
 	default:
 		ASSERT(0);
@@ -126,10 +126,10 @@ xfs_ag_resv_needed(
 {
 	xfs_extlen_t			len;
 
-	len = pag->pag_meta_resv.ar_reserved + pag->pag_agfl_resv.ar_reserved;
+	len = pag->pag_meta_resv.ar_reserved + pag->pag_rmapbt_resv.ar_reserved;
 	switch (type) {
 	case XFS_AG_RESV_METADATA:
-	case XFS_AG_RESV_AGFL:
+	case XFS_AG_RESV_RMAPBT:
 		len -= xfs_perag_resv(pag, type)->ar_reserved;
 		break;
 	case XFS_AG_RESV_NONE:
@@ -160,10 +160,11 @@ __xfs_ag_resv_free(
 	if (pag->pag_agno == 0)
 		pag->pag_mount->m_ag_max_usable += resv->ar_asked;
 	/*
-	 * AGFL blocks are always considered "free", so whatever
-	 * was reserved at mount time must be given back at umount.
+	 * RMAPBT blocks come from the AGFL and AGFL blocks are always
+	 * considered "free", so whatever was reserved at mount time must be
+	 * given back at umount.
 	 */
-	if (type == XFS_AG_RESV_AGFL)
+	if (type == XFS_AG_RESV_RMAPBT)
 		oldresv = resv->ar_orig_reserved;
 	else
 		oldresv = resv->ar_reserved;
@@ -185,7 +186,7 @@ xfs_ag_resv_free(
 	int				error;
 	int				err2;
 
-	error = __xfs_ag_resv_free(pag, XFS_AG_RESV_AGFL);
+	error = __xfs_ag_resv_free(pag, XFS_AG_RESV_RMAPBT);
 	err2 = __xfs_ag_resv_free(pag, XFS_AG_RESV_METADATA);
 	if (err2 && !error)
 		error = err2;
@@ -284,15 +285,15 @@ xfs_ag_resv_init(
 		}
 	}
 
-	/* Create the AGFL metadata reservation */
-	if (pag->pag_agfl_resv.ar_asked == 0) {
+	/* Create the RMAPBT metadata reservation */
+	if (pag->pag_rmapbt_resv.ar_asked == 0) {
 		ask = used = 0;
 
 		error = xfs_rmapbt_calc_reserves(mp, agno, &ask, &used);
 		if (error)
 			goto out;
 
-		error = __xfs_ag_resv_init(pag, XFS_AG_RESV_AGFL, ask, used);
+		error = __xfs_ag_resv_init(pag, XFS_AG_RESV_RMAPBT, ask, used);
 		if (error)
 			goto out;
 	}
@@ -304,7 +305,7 @@ xfs_ag_resv_init(
 		return error;
 
 	ASSERT(xfs_perag_resv(pag, XFS_AG_RESV_METADATA)->ar_reserved +
-	       xfs_perag_resv(pag, XFS_AG_RESV_AGFL)->ar_reserved <=
+	       xfs_perag_resv(pag, XFS_AG_RESV_RMAPBT)->ar_reserved <=
 	       pag->pagf_freeblks + pag->pagf_flcount);
 #endif
 out:
@@ -326,7 +327,7 @@ xfs_ag_resv_alloc_extent(
 
 	switch (type) {
 	case XFS_AG_RESV_METADATA:
-	case XFS_AG_RESV_AGFL:
+	case XFS_AG_RESV_RMAPBT:
 		resv = xfs_perag_resv(pag, type);
 		break;
 	default:
@@ -341,7 +342,7 @@ xfs_ag_resv_alloc_extent(
 
 	len = min_t(xfs_extlen_t, args->len, resv->ar_reserved);
 	resv->ar_reserved -= len;
-	if (type == XFS_AG_RESV_AGFL)
+	if (type == XFS_AG_RESV_RMAPBT)
 		return;
 	/* Allocations of reserved blocks only need on-disk sb updates... */
 	xfs_trans_mod_sb(args->tp, XFS_TRANS_SB_RES_FDBLOCKS, -(int64_t)len);
@@ -366,7 +367,7 @@ xfs_ag_resv_free_extent(
 
 	switch (type) {
 	case XFS_AG_RESV_METADATA:
-	case XFS_AG_RESV_AGFL:
+	case XFS_AG_RESV_RMAPBT:
 		resv = xfs_perag_resv(pag, type);
 		break;
 	default:
@@ -379,7 +380,7 @@ xfs_ag_resv_free_extent(
 
 	leftover = min_t(xfs_extlen_t, len, resv->ar_asked - resv->ar_reserved);
 	resv->ar_reserved += leftover;
-	if (type == XFS_AG_RESV_AGFL)
+	if (type == XFS_AG_RESV_RMAPBT)
 		return;
 	/* Freeing into the reserved pool only requires on-disk update... */
 	xfs_trans_mod_sb(tp, XFS_TRANS_SB_RES_FDBLOCKS, len);