---

yaml
---
r: 307707
b: refs/heads/master
c: 507630b
h: refs/heads/master
i:
  307705: 05daacb
  307703: e9c404d
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 193aec10504e4c24521449c46317282141fb36e8
+refs/heads/master: 507630b29f13a3d8689895618b12015308402e22

trunk/fs/xfs/xfs_aops.c

@@ -1146,7 +1146,14 @@ __xfs_get_blocks(
 	if (!create && direct && offset >= i_size_read(inode))
 		return 0;
 
-	if (create) {
+	/*
+	 * Direct I/O is usually done on preallocated files, so try getting
+	 * a block mapping without an exclusive lock first.  For buffered
+	 * writes we already have the exclusive iolock anyway, so avoiding
+	 * a lock roundtrip here by taking the ilock exclusive from the
+	 * beginning is a useful micro optimization.
+	 */
+	if (create && !direct) {
 		lockmode = XFS_ILOCK_EXCL;
 		xfs_ilock(ip, lockmode);
 	} else {
@@ -1169,22 +1176,37 @@ __xfs_get_blocks(
 	     (imap.br_startblock == HOLESTARTBLOCK ||
 	      imap.br_startblock == DELAYSTARTBLOCK))) {
 		if (direct) {
+			/*
+			 * Drop the ilock in preparation for starting the block
+			 * allocation transaction.  It will be retaken
+			 * exclusively inside xfs_iomap_write_direct for the
+			 * actual allocation.
+			 */
+			xfs_iunlock(ip, lockmode);
 			error = xfs_iomap_write_direct(ip, offset, size,
 						       &imap, nimaps);
+			if (error)
+				return -error;
 		} else {
+			/*
+			 * Delalloc reservations do not require a transaction,
+			 * we can go on without dropping the lock here.
+			 */
 			error = xfs_iomap_write_delay(ip, offset, size, &imap);
+			if (error)
+				goto out_unlock;
+
+			xfs_iunlock(ip, lockmode);
 		}
-		if (error)
-			goto out_unlock;
 
 		trace_xfs_get_blocks_alloc(ip, offset, size, 0, &imap);
 	} else if (nimaps) {
 		trace_xfs_get_blocks_found(ip, offset, size, 0, &imap);
+		xfs_iunlock(ip, lockmode);
 	} else {
 		trace_xfs_get_blocks_notfound(ip, offset, size);
 		goto out_unlock;
 	}
-	xfs_iunlock(ip, lockmode);
 
 	if (imap.br_startblock != HOLESTARTBLOCK &&
 	    imap.br_startblock != DELAYSTARTBLOCK) {

trunk/fs/xfs/xfs_iomap.c

@@ -142,11 +142,7 @@ xfs_iomap_write_direct(
 	int		committed;
 	int		error;
 
-	/*
-	 * Make sure that the dquots are there. This doesn't hold
-	 * the ilock across a disk read.
-	 */
-	error = xfs_qm_dqattach_locked(ip, 0);
+	error = xfs_qm_dqattach(ip, 0);
 	if (error)
 		return XFS_ERROR(error);
 
@@ -158,7 +154,7 @@ xfs_iomap_write_direct(
 	if ((offset + count) > XFS_ISIZE(ip)) {
 		error = xfs_iomap_eof_align_last_fsb(mp, ip, extsz, &last_fsb);
 		if (error)
-			goto error_out;
+			return XFS_ERROR(error);
 	} else {
 		if (nmaps && (imap->br_startblock == HOLESTARTBLOCK))
 			last_fsb = MIN(last_fsb, (xfs_fileoff_t)
@@ -190,7 +186,6 @@ xfs_iomap_write_direct(
 	/*
 	 * Allocate and setup the transaction
 	 */
-	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 	tp = xfs_trans_alloc(mp, XFS_TRANS_DIOSTRAT);
 	error = xfs_trans_reserve(tp, resblks,
 			XFS_WRITE_LOG_RES(mp), resrtextents,
@@ -199,15 +194,16 @@ xfs_iomap_write_direct(
 	/*
 	 * Check for running out of space, note: need lock to return
 	 */
-	if (error)
+	if (error) {
 		xfs_trans_cancel(tp, 0);
+		return XFS_ERROR(error);
+	}
+
 	xfs_ilock(ip, XFS_ILOCK_EXCL);
-	if (error)
-		goto error_out;
 
 	error = xfs_trans_reserve_quota_nblks(tp, ip, qblocks, 0, quota_flag);
 	if (error)
-		goto error1;
+		goto out_trans_cancel;
 
 	xfs_trans_ijoin(tp, ip, 0);
 
@@ -224,42 +220,39 @@ xfs_iomap_write_direct(
 	error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb, bmapi_flag,
 				&firstfsb, 0, imap, &nimaps, &free_list);
 	if (error)
-		goto error0;
+		goto out_bmap_cancel;
 
 	/*
 	 * Complete the transaction
 	 */
 	error = xfs_bmap_finish(&tp, &free_list, &committed);
 	if (error)
-		goto error0;
+		goto out_bmap_cancel;
 	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
 	if (error)
-		goto error_out;
+		goto out_unlock;
 
 	/*
 	 * Copy any maps to caller's array and return any error.
 	 */
 	if (nimaps == 0) {
-		error = ENOSPC;
-		goto error_out;
+		error = XFS_ERROR(ENOSPC);
+		goto out_unlock;
 	}
 
-	if (!(imap->br_startblock || XFS_IS_REALTIME_INODE(ip))) {
+	if (!(imap->br_startblock || XFS_IS_REALTIME_INODE(ip)))
 		error = xfs_alert_fsblock_zero(ip, imap);
-		goto error_out;
-	}
 
-	return 0;
+out_unlock:
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	return error;
 
-error0:	/* Cancel bmap, unlock inode, unreserve quota blocks, cancel trans */
+out_bmap_cancel:
 	xfs_bmap_cancel(&free_list);
 	xfs_trans_unreserve_quota_nblks(tp, ip, qblocks, 0, quota_flag);
-
-error1:	/* Just cancel transaction */
+out_trans_cancel:
 	xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
-
-error_out:
-	return XFS_ERROR(error);
+	goto out_unlock;
 }
 
 /*