1 files changed, 54 insertions, 16 deletions

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 1f86033171c8..f4f5b43cf647 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -131,20 +131,30 @@ xfs_iomap_write_direct(
 	uint		qblocks, resblks, resrtextents;
 	int		committed;
 	int		error;
-
-	error = xfs_qm_dqattach(ip, 0);
-	if (error)
-		return error;
+	int		lockmode;
+	int		bmapi_flags = XFS_BMAPI_PREALLOC;
 
 	rt = XFS_IS_REALTIME_INODE(ip);
 	extsz = xfs_get_extsz_hint(ip);
+	lockmode = XFS_ILOCK_SHARED;	/* locked by caller */
+
+	ASSERT(xfs_isilocked(ip, lockmode));
 
 	offset_fsb = XFS_B_TO_FSBT(mp, offset);
 	last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count)));
 	if ((offset + count) > XFS_ISIZE(ip)) {
+		/*
+		 * Assert that the in-core extent list is present since this can
+		 * call xfs_iread_extents() and we only have the ilock shared.
+		 * This should be safe because the lock was held around a bmapi
+		 * call in the caller and we only need it to access the in-core
+		 * list.
+		 */
+		ASSERT(XFS_IFORK_PTR(ip, XFS_DATA_FORK)->if_flags &
+								XFS_IFEXTENTS);
 		error = xfs_iomap_eof_align_last_fsb(mp, ip, extsz, &last_fsb);
 		if (error)
-			return error;
+			goto out_unlock;
 	} else {
 		if (nmaps && (imap->br_startblock == HOLESTARTBLOCK))
 			last_fsb = MIN(last_fsb, (xfs_fileoff_t)
@@ -174,9 +184,35 @@ xfs_iomap_write_direct(
 	}
 
 	/*
+	 * Drop the shared lock acquired by the caller, attach the dquot if
+	 * necessary and move on to transaction setup.
+	 */
+	xfs_iunlock(ip, lockmode);
+	error = xfs_qm_dqattach(ip, 0);
+	if (error)
+		return error;
+
+	/*
 	 * Allocate and setup the transaction
 	 */
 	tp = xfs_trans_alloc(mp, XFS_TRANS_DIOSTRAT);
+
+	/*
+	 * For DAX, we do not allocate unwritten extents, but instead we zero
+	 * the block before we commit the transaction.  Ideally we'd like to do
+	 * this outside the transaction context, but if we commit and then crash
+	 * we may not have zeroed the blocks and this will be exposed on
+	 * recovery of the allocation. Hence we must zero before commit.
+	 * Further, if we are mapping unwritten extents here, we need to zero
+	 * and convert them to written so that we don't need an unwritten extent
+	 * callback for DAX. This also means that we need to be able to dip into
+	 * the reserve block pool if there is no space left but we need to do
+	 * unwritten extent conversion.
+	 */
+	if (IS_DAX(VFS_I(ip))) {
+		bmapi_flags = XFS_BMAPI_CONVERT | XFS_BMAPI_ZERO;
+		tp->t_flags |= XFS_TRANS_RESERVE;
+	}
 	error = xfs_trans_reserve(tp, &M_RES(mp)->tr_write,
 				  resblks, resrtextents);
 	/*
@@ -187,7 +223,8 @@ xfs_iomap_write_direct(
 		return error;
 	}
 
-	xfs_ilock(ip, XFS_ILOCK_EXCL);
+	lockmode = XFS_ILOCK_EXCL;
+	xfs_ilock(ip, lockmode);
 
 	error = xfs_trans_reserve_quota_nblks(tp, ip, qblocks, 0, quota_flag);
 	if (error)
@@ -202,8 +239,8 @@ xfs_iomap_write_direct(
 	xfs_bmap_init(&free_list, &firstfsb);
 	nimaps = 1;
 	error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb,
-				XFS_BMAPI_PREALLOC, &firstfsb, 0,
-				imap, &nimaps, &free_list);
+				bmapi_flags, &firstfsb, resblks, imap,
+				&nimaps, &free_list);
 	if (error)
 		goto out_bmap_cancel;
 
@@ -213,6 +250,7 @@ xfs_iomap_write_direct(
 	error = xfs_bmap_finish(&tp, &free_list, &committed);
 	if (error)
 		goto out_bmap_cancel;
+
 	error = xfs_trans_commit(tp);
 	if (error)
 		goto out_unlock;
@@ -229,7 +267,7 @@ xfs_iomap_write_direct(
 		error = xfs_alert_fsblock_zero(ip, imap);
 
 out_unlock:
-	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	xfs_iunlock(ip, lockmode);
 	return error;
 
 out_bmap_cancel:
@@ -670,7 +708,7 @@ xfs_iomap_write_allocate(
 	count_fsb = imap->br_blockcount;
 	map_start_fsb = imap->br_startoff;
 
-	XFS_STATS_ADD(xs_xstrat_bytes, XFS_FSB_TO_B(mp, count_fsb));
+	XFS_STATS_ADD(mp, xs_xstrat_bytes, XFS_FSB_TO_B(mp, count_fsb));
 
 	while (count_fsb != 0) {
 		/*
@@ -750,9 +788,9 @@ xfs_iomap_write_allocate(
 			 * pointer that the caller gave to us.
 			 */
 			error = xfs_bmapi_write(tp, ip, map_start_fsb,
-						count_fsb, 0,
-						&first_block, 1,
-						imap, &nimaps, &free_list);
+						count_fsb, 0, &first_block,
+						nres, imap, &nimaps,
+						&free_list);
 			if (error)
 				goto trans_cancel;
 
@@ -777,7 +815,7 @@ xfs_iomap_write_allocate(
 		if ((offset_fsb >= imap->br_startoff) &&
 		    (offset_fsb < (imap->br_startoff +
 				   imap->br_blockcount))) {
-			XFS_STATS_INC(xs_xstrat_quick);
+			XFS_STATS_INC(mp, xs_xstrat_quick);
 			return 0;
 		}
 
@@ -866,8 +904,8 @@ xfs_iomap_write_unwritten(
 		xfs_bmap_init(&free_list, &firstfsb);
 		nimaps = 1;
 		error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb,
-				  XFS_BMAPI_CONVERT, &firstfsb,
-				  1, &imap, &nimaps, &free_list);
+					XFS_BMAPI_CONVERT, &firstfsb, resblks,
+					&imap, &nimaps, &free_list);
 		if (error)
 			goto error_on_bmapi_transaction;