[PATCH 09/10] xfs: kill the dop_low flag

[Christoph Hellwig <hch@lst.de>]

Now that we always get our space reservations right in xfs_bmapi_write
we can remove the last remains of the dangerous low space allocator mode.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/libxfs/xfs_bmap.c       | 12 +-----------
 fs/xfs/libxfs/xfs_bmap_btree.c |  2 --
 fs/xfs/libxfs/xfs_defer.c      |  1 -
 fs/xfs/libxfs/xfs_defer.h      | 15 ---------------
 fs/xfs/xfs_filestream.c        |  2 --
 fs/xfs/xfs_trace.h             | 12 +++---------
 6 files changed, 4 insertions(+), 40 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index c06e7d500ed1..9e3f0e6a9062 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -762,9 +762,6 @@ xfs_bmap_extents_to_btree(
 	if (*firstblock == NULLFSBLOCK) {
 		args.type = XFS_ALLOCTYPE_START_BNO;
 		args.fsbno = XFS_INO_TO_FSB(mp, ip->i_ino);
-	} else if (dfops->dop_low) {
-		args.type = XFS_ALLOCTYPE_START_BNO;
-		args.fsbno = *firstblock;
 	} else {
 		args.type = XFS_ALLOCTYPE_NEAR_BNO;
 		args.fsbno = *firstblock;
@@ -3677,12 +3674,6 @@ xfs_bmap_btalloc(
 			error = xfs_bmap_btalloc_nullfb(ap, &args, &blen);
 		if (error)
 			return error;
-	} else if (ap->dfops->dop_low) {
-		if (xfs_inode_is_filestream(ap->ip))
-			args.type = XFS_ALLOCTYPE_FIRST_AG;
-		else
-			args.type = XFS_ALLOCTYPE_START_BNO;
-		args.minlen = 1;
 	} else {
 		args.type = XFS_ALLOCTYPE_NEAR_BNO;
 		args.minlen = 1;
@@ -3709,7 +3700,7 @@ xfs_bmap_btalloc(
 	 * is >= the stripe unit and the allocation offset is
 	 * at the end of file.
 	 */
-	if (!ap->dfops->dop_low && ap->aeof) {
+	if (ap->aeof) {
 		if (!ap->offset) {
 			args.alignment = stripe_align;
 			atype = args.type;
@@ -3816,7 +3807,6 @@ xfs_bmap_btalloc(
 		args.type = XFS_ALLOCTYPE_FIRST_AG;
 		if ((error = xfs_alloc_vextent(&args)))
 			return error;
-		ap->dfops->dop_low = true;
 	}
 	if (args.fsbno != NULLFSBLOCK) {
 		/*
diff --git a/fs/xfs/libxfs/xfs_bmap_btree.c b/fs/xfs/libxfs/xfs_bmap_btree.c
index 153c969febd4..b9f0f61bd8ee 100644
--- a/fs/xfs/libxfs/xfs_bmap_btree.c
+++ b/fs/xfs/libxfs/xfs_bmap_btree.c
@@ -462,8 +462,6 @@ xfs_bmbt_alloc_block(
 		 */
 		if (xfs_trans_blk_res(args.tp))
 			args.minleft = xfs_trans_blk_res(args.tp) - args.maxlen;
-	} else if (cur->bc_private.b.dfops->dop_low) {
-		args.type = XFS_ALLOCTYPE_START_BNO;
 	} else {
 		args.type = XFS_ALLOCTYPE_NEAR_BNO;
 	}
diff --git a/fs/xfs/libxfs/xfs_defer.c b/fs/xfs/libxfs/xfs_defer.c
index 5c2929f94bd3..172d583c6f1c 100644
--- a/fs/xfs/libxfs/xfs_defer.c
+++ b/fs/xfs/libxfs/xfs_defer.c
@@ -503,7 +503,6 @@ xfs_defer_init(
 	xfs_fsblock_t			*fbp)
 {
 	dop->dop_committed = false;
-	dop->dop_low = false;
 	memset(&dop->dop_inodes, 0, sizeof(dop->dop_inodes));
 	*fbp = NULLFSBLOCK;
 	INIT_LIST_HEAD(&dop->dop_intake);
diff --git a/fs/xfs/libxfs/xfs_defer.h b/fs/xfs/libxfs/xfs_defer.h
index f6e93ef0bffe..cc1acd1fd4e8 100644
--- a/fs/xfs/libxfs/xfs_defer.h
+++ b/fs/xfs/libxfs/xfs_defer.h
@@ -36,20 +36,6 @@ struct xfs_defer_pending {
 	unsigned int			dfp_count;	/* # extent items */
 };
 
-/*
- * Header for deferred operation list.
- *
- * dop_low is used by the allocator to activate the lowspace algorithm -
- * when free space is running low the extent allocator may choose to
- * allocate an extent from an AG without leaving sufficient space for
- * a btree split when inserting the new extent.  In this case the allocator
- * will enable the lowspace algorithm which is supposed to allow further
- * allocations (such as btree splits and newroots) to allocate from
- * sequential AGs.  In order to avoid locking AGs out of order the lowspace
- * algorithm will start searching for free space from AG 0.  If the correct
- * transaction reservations have been made then this algorithm will eventually
- * find all the space it needs.
- */
 enum xfs_defer_ops_type {
 	XFS_DEFER_OPS_TYPE_BMAP,
 	XFS_DEFER_OPS_TYPE_REFCOUNT,
@@ -62,7 +48,6 @@ enum xfs_defer_ops_type {
 
 struct xfs_defer_ops {
 	bool			dop_committed;	/* did any trans commit? */
-	bool			dop_low;	/* alloc in low mode */
 	struct list_head	dop_intake;	/* unlogged pending work */
 	struct list_head	dop_pending;	/* logged pending work */
 
diff --git a/fs/xfs/xfs_filestream.c b/fs/xfs/xfs_filestream.c
index 043ca3808ea2..6d61e61c0700 100644
--- a/fs/xfs/xfs_filestream.c
+++ b/fs/xfs/xfs_filestream.c
@@ -390,8 +390,6 @@ xfs_filestream_new_ag(
 
 	if (xfs_alloc_is_userdata(ap->datatype))
 		flags |= XFS_PICK_USERDATA;
-	if (ap->dfops->dop_low)
-		flags |= XFS_PICK_LOWSPACE;
 
 	err = xfs_filestream_pick_ag(pip, startag, agp, flags, minlen);
 
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index cba10daf8391..ab4ce20b00dd 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -2256,19 +2256,16 @@ DECLARE_EVENT_CLASS(xfs_defer_class,
 		__field(dev_t, dev)
 		__field(void *, dop)
 		__field(bool, committed)
-		__field(bool, low)
 	),
 	TP_fast_assign(
 		__entry->dev = mp ? mp->m_super->s_dev : 0;
 		__entry->dop = dop;
 		__entry->committed = dop->dop_committed;
-		__entry->low = dop->dop_low;
 	),
-	TP_printk("dev %d:%d ops %p committed %d low %d\n",
+	TP_printk("dev %d:%d ops %p committed %d\n",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  __entry->dop,
-		  __entry->committed,
-		  __entry->low)
+		  __entry->committed)
 )
 #define DEFINE_DEFER_EVENT(name) \
 DEFINE_EVENT(xfs_defer_class, name, \
@@ -2282,21 +2279,18 @@ DECLARE_EVENT_CLASS(xfs_defer_error_class,
 		__field(dev_t, dev)
 		__field(void *, dop)
 		__field(bool, committed)
-		__field(bool, low)
 		__field(int, error)
 	),
 	TP_fast_assign(
 		__entry->dev = mp ? mp->m_super->s_dev : 0;
 		__entry->dop = dop;
 		__entry->committed = dop->dop_committed;
-		__entry->low = dop->dop_low;
 		__entry->error = error;
 	),
-	TP_printk("dev %d:%d ops %p committed %d low %d err %d\n",
+	TP_printk("dev %d:%d ops %p committed %d err %d\n",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  __entry->dop,
 		  __entry->committed,
-		  __entry->low,
 		  __entry->error)
 )
 #define DEFINE_DEFER_ERROR_EVENT(name) \
-- 
2.11.0