1 files changed, 38 insertions, 144 deletions

diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index b32a66452d44..47acf4096022 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -107,7 +107,8 @@ xfs_trans_dup(
 
 	ntp->t_flags = XFS_TRANS_PERM_LOG_RES |
 		       (tp->t_flags & XFS_TRANS_RESERVE) |
-		       (tp->t_flags & XFS_TRANS_NO_WRITECOUNT);
+		       (tp->t_flags & XFS_TRANS_NO_WRITECOUNT) |
+		       (tp->t_flags & XFS_TRANS_RES_FDBLKS);
 	/* We gave our writer reference to the new transaction */
 	tp->t_flags |= XFS_TRANS_NO_WRITECOUNT;
 	ntp->t_ticket = xfs_log_ticket_get(tp->t_ticket);
@@ -273,6 +274,8 @@ xfs_trans_alloc(
 	 */
 	WARN_ON(resp->tr_logres > 0 &&
 		mp->m_super->s_writers.frozen == SB_FREEZE_COMPLETE);
+	ASSERT(!(flags & XFS_TRANS_RES_FDBLKS) ||
+	       xfs_sb_version_haslazysbcount(&mp->m_sb));
 	atomic_inc(&mp->m_active_trans);
 
 	tp->t_magic = XFS_TRANS_HEADER_MAGIC;
@@ -368,6 +371,20 @@ xfs_trans_mod_sb(
 			tp->t_blk_res_used += (uint)-delta;
 			if (tp->t_blk_res_used > tp->t_blk_res)
 				xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
+		} else if (delta > 0 && (tp->t_flags & XFS_TRANS_RES_FDBLKS)) {
+			int64_t	blkres_delta;
+
+			/*
+			 * Return freed blocks directly to the reservation
+			 * instead of the global pool, being careful not to
+			 * overflow the trans counter. This is used to preserve
+			 * reservation across chains of transaction rolls that
+			 * repeatedly free and allocate blocks.
+			 */
+			blkres_delta = min_t(int64_t, delta,
+					     UINT_MAX - tp->t_blk_res);
+			tp->t_blk_res += blkres_delta;
+			delta -= blkres_delta;
 		}
 		tp->t_fdblocks_delta += delta;
 		if (xfs_sb_version_haslazysbcount(&mp->m_sb))
@@ -532,57 +549,9 @@ 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.
@@ -627,20 +596,17 @@ 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;
+		ASSERT(!error);
 	}
 
 	if (ifreedelta) {
 		error = xfs_mod_ifree(mp, ifreedelta);
-		if (error)
-			goto out_undo_icount;
+		ASSERT(!error);
 	}
 
 	if (rtxdelta == 0 && !(tp->t_flags & XFS_TRANS_SB_DIRTY))
@@ -648,95 +614,23 @@ 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;
 }