1 files changed, 42 insertions, 161 deletions

diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index 28b983ff8b11..3c94e5ff4316 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -68,7 +68,6 @@ xfs_trans_free(
 	xfs_extent_busy_clear(tp->t_mountp, &tp->t_busy, false);
 
 	trace_xfs_trans_free(tp, _RET_IP_);
-	atomic_dec(&tp->t_mountp->m_active_trans);
 	if (!(tp->t_flags & XFS_TRANS_NO_WRITECOUNT))
 		sb_end_intwrite(tp->t_mountp->m_super);
 	xfs_trans_free_dqinfo(tp);
@@ -125,8 +124,6 @@ xfs_trans_dup(
 	xfs_defer_move(ntp, tp);
 
 	xfs_trans_dup_dqinfo(tp, ntp);
-
-	atomic_inc(&tp->t_mountp->m_active_trans);
 	return ntp;
 }
 
@@ -275,7 +272,6 @@ xfs_trans_alloc(
 	 */
 	WARN_ON(resp->tr_logres > 0 &&
 		mp->m_super->s_writers.frozen == SB_FREEZE_COMPLETE);
-	atomic_inc(&mp->m_active_trans);
 
 	tp->t_magic = XFS_TRANS_HEADER_MAGIC;
 	tp->t_flags = flags;
@@ -299,20 +295,19 @@ xfs_trans_alloc(
 
 /*
  * Create an empty transaction with no reservation.  This is a defensive
- * mechanism for routines that query metadata without actually modifying
- * them -- if the metadata being queried is somehow cross-linked (think a
- * btree block pointer that points higher in the tree), we risk deadlock.
- * However, blocks grabbed as part of a transaction can be re-grabbed.
- * The verifiers will notice the corrupt block and the operation will fail
- * back to userspace without deadlocking.
+ * mechanism for routines that query metadata without actually modifying them --
+ * if the metadata being queried is somehow cross-linked (think a btree block
+ * pointer that points higher in the tree), we risk deadlock.  However, blocks
+ * grabbed as part of a transaction can be re-grabbed.  The verifiers will
+ * notice the corrupt block and the operation will fail back to userspace
+ * without deadlocking.
  *
- * Note the zero-length reservation; this transaction MUST be cancelled
- * without any dirty data.
+ * Note the zero-length reservation; this transaction MUST be cancelled without
+ * any dirty data.
  *
- * Callers should obtain freeze protection to avoid two conflicts with fs
- * freezing: (1) having active transactions trip the m_active_trans ASSERTs;
- * and (2) grabbing buffers at the same time that freeze is trying to drain
- * the buffer LRU list.
+ * Callers should obtain freeze protection to avoid a conflict with fs freezing
+ * where we can be grabbing buffers at the same time that freeze is trying to
+ * drain the buffer LRU list.
  */
 int
 xfs_trans_alloc_empty(
@@ -534,57 +529,9 @@ xfs_trans_apply_sb_deltas(
 				  sizeof(sbp->sb_frextents) - 1);
 }
 
-STATIC int
-xfs_sb_mod8(
-	uint8_t			*field,
-	int8_t			delta)
-{
-	int8_t			counter = *field;
-
-	counter += delta;
-	if (counter < 0) {
-		ASSERT(0);
-		return -EINVAL;
-	}
-	*field = counter;
-	return 0;
-}
-
-STATIC int
-xfs_sb_mod32(
-	uint32_t		*field,
-	int32_t			delta)
-{
-	int32_t			counter = *field;
-
-	counter += delta;
-	if (counter < 0) {
-		ASSERT(0);
-		return -EINVAL;
-	}
-	*field = counter;
-	return 0;
-}
-
-STATIC int
-xfs_sb_mod64(
-	uint64_t		*field,
-	int64_t			delta)
-{
-	int64_t			counter = *field;
-
-	counter += delta;
-	if (counter < 0) {
-		ASSERT(0);
-		return -EINVAL;
-	}
-	*field = counter;
-	return 0;
-}
-
 /*
- * xfs_trans_unreserve_and_mod_sb() is called to release unused reservations
- * and apply superblock counter changes to the in-core superblock.  The
+ * xfs_trans_unreserve_and_mod_sb() is called to release unused reservations and
+ * apply superblock counter changes to the in-core superblock.  The
  * t_res_fdblocks_delta and t_res_frextents_delta fields are explicitly NOT
  * applied to the in-core superblock.  The idea is that that has already been
  * done.
@@ -593,7 +540,12 @@ xfs_sb_mod64(
  * used block counts are not updated in the on disk superblock. In this case,
  * XFS_TRANS_SB_DIRTY will not be set when the transaction is updated but we
  * still need to update the incore superblock with the changes.
+ *
+ * Deltas for the inode count are +/-64, hence we use a large batch size of 128
+ * so we don't need to take the counter lock on every update.
  */
+#define XFS_ICOUNT_BATCH	128
+
 void
 xfs_trans_unreserve_and_mod_sb(
 	struct xfs_trans	*tp)
@@ -629,20 +581,21 @@ xfs_trans_unreserve_and_mod_sb(
 	/* apply the per-cpu counters */
 	if (blkdelta) {
 		error = xfs_mod_fdblocks(mp, blkdelta, rsvd);
-		if (error)
-			goto out;
+		ASSERT(!error);
 	}
 
 	if (idelta) {
-		error = xfs_mod_icount(mp, idelta);
-		if (error)
-			goto out_undo_fdblocks;
+		percpu_counter_add_batch(&mp->m_icount, idelta,
+					 XFS_ICOUNT_BATCH);
+		if (idelta < 0)
+			ASSERT(__percpu_counter_compare(&mp->m_icount, 0,
+							XFS_ICOUNT_BATCH) >= 0);
 	}
 
 	if (ifreedelta) {
-		error = xfs_mod_ifree(mp, ifreedelta);
-		if (error)
-			goto out_undo_icount;
+		percpu_counter_add(&mp->m_ifree, ifreedelta);
+		if (ifreedelta < 0)
+			ASSERT(percpu_counter_compare(&mp->m_ifree, 0) >= 0);
 	}
 
 	if (rtxdelta == 0 && !(tp->t_flags & XFS_TRANS_SB_DIRTY))
@@ -650,95 +603,23 @@ xfs_trans_unreserve_and_mod_sb(
 
 	/* apply remaining deltas */
 	spin_lock(&mp->m_sb_lock);
-	if (rtxdelta) {
-		error = xfs_sb_mod64(&mp->m_sb.sb_frextents, rtxdelta);
-		if (error)
-			goto out_undo_ifree;
-	}
-
-	if (tp->t_dblocks_delta != 0) {
-		error = xfs_sb_mod64(&mp->m_sb.sb_dblocks, tp->t_dblocks_delta);
-		if (error)
-			goto out_undo_frextents;
-	}
-	if (tp->t_agcount_delta != 0) {
-		error = xfs_sb_mod32(&mp->m_sb.sb_agcount, tp->t_agcount_delta);
-		if (error)
-			goto out_undo_dblocks;
-	}
-	if (tp->t_imaxpct_delta != 0) {
-		error = xfs_sb_mod8(&mp->m_sb.sb_imax_pct, tp->t_imaxpct_delta);
-		if (error)
-			goto out_undo_agcount;
-	}
-	if (tp->t_rextsize_delta != 0) {
-		error = xfs_sb_mod32(&mp->m_sb.sb_rextsize,
-				     tp->t_rextsize_delta);
-		if (error)
-			goto out_undo_imaxpct;
-	}
-	if (tp->t_rbmblocks_delta != 0) {
-		error = xfs_sb_mod32(&mp->m_sb.sb_rbmblocks,
-				     tp->t_rbmblocks_delta);
-		if (error)
-			goto out_undo_rextsize;
-	}
-	if (tp->t_rblocks_delta != 0) {
-		error = xfs_sb_mod64(&mp->m_sb.sb_rblocks, tp->t_rblocks_delta);
-		if (error)
-			goto out_undo_rbmblocks;
-	}
-	if (tp->t_rextents_delta != 0) {
-		error = xfs_sb_mod64(&mp->m_sb.sb_rextents,
-				     tp->t_rextents_delta);
-		if (error)
-			goto out_undo_rblocks;
-	}
-	if (tp->t_rextslog_delta != 0) {
-		error = xfs_sb_mod8(&mp->m_sb.sb_rextslog,
-				     tp->t_rextslog_delta);
-		if (error)
-			goto out_undo_rextents;
-	}
+	mp->m_sb.sb_frextents += rtxdelta;
+	mp->m_sb.sb_dblocks += tp->t_dblocks_delta;
+	mp->m_sb.sb_agcount += tp->t_agcount_delta;
+	mp->m_sb.sb_imax_pct += tp->t_imaxpct_delta;
+	mp->m_sb.sb_rextsize += tp->t_rextsize_delta;
+	mp->m_sb.sb_rbmblocks += tp->t_rbmblocks_delta;
+	mp->m_sb.sb_rblocks += tp->t_rblocks_delta;
+	mp->m_sb.sb_rextents += tp->t_rextents_delta;
+	mp->m_sb.sb_rextslog += tp->t_rextslog_delta;
 	spin_unlock(&mp->m_sb_lock);
-	return;
 
-out_undo_rextents:
-	if (tp->t_rextents_delta)
-		xfs_sb_mod64(&mp->m_sb.sb_rextents, -tp->t_rextents_delta);
-out_undo_rblocks:
-	if (tp->t_rblocks_delta)
-		xfs_sb_mod64(&mp->m_sb.sb_rblocks, -tp->t_rblocks_delta);
-out_undo_rbmblocks:
-	if (tp->t_rbmblocks_delta)
-		xfs_sb_mod32(&mp->m_sb.sb_rbmblocks, -tp->t_rbmblocks_delta);
-out_undo_rextsize:
-	if (tp->t_rextsize_delta)
-		xfs_sb_mod32(&mp->m_sb.sb_rextsize, -tp->t_rextsize_delta);
-out_undo_imaxpct:
-	if (tp->t_rextsize_delta)
-		xfs_sb_mod8(&mp->m_sb.sb_imax_pct, -tp->t_imaxpct_delta);
-out_undo_agcount:
-	if (tp->t_agcount_delta)
-		xfs_sb_mod32(&mp->m_sb.sb_agcount, -tp->t_agcount_delta);
-out_undo_dblocks:
-	if (tp->t_dblocks_delta)
-		xfs_sb_mod64(&mp->m_sb.sb_dblocks, -tp->t_dblocks_delta);
-out_undo_frextents:
-	if (rtxdelta)
-		xfs_sb_mod64(&mp->m_sb.sb_frextents, -rtxdelta);
-out_undo_ifree:
-	spin_unlock(&mp->m_sb_lock);
-	if (ifreedelta)
-		xfs_mod_ifree(mp, -ifreedelta);
-out_undo_icount:
-	if (idelta)
-		xfs_mod_icount(mp, -idelta);
-out_undo_fdblocks:
-	if (blkdelta)
-		xfs_mod_fdblocks(mp, -blkdelta, rsvd);
-out:
-	ASSERT(error == 0);
+	/*
+	 * Debug checks outside of the spinlock so they don't lock up the
+	 * machine if they fail.
+	 */
+	ASSERT(mp->m_sb.sb_imax_pct >= 0);
+	ASSERT(mp->m_sb.sb_rextslog >= 0);
 	return;
 }