1 files changed, 74 insertions, 10 deletions

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 22b62a179e8..55582bd6665 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -267,6 +267,9 @@ error_out:
  * If the caller is doing a write at the end of the file, then extend the
  * allocation out to the file system's write iosize.  We clean up any extra
  * space left over when the file is closed in xfs_inactive().
+ *
+ * If we find we already have delalloc preallocation beyond EOF, don't do more
+ * preallocation as it it not needed.
  */
 STATIC int
 xfs_iomap_eof_want_preallocate(
@@ -282,6 +285,7 @@ xfs_iomap_eof_want_preallocate(
 	xfs_filblks_t   count_fsb;
 	xfs_fsblock_t	firstblock;
 	int		n, error, imaps;
+	int		found_delalloc = 0;
 
 	*prealloc = 0;
 	if ((offset + count) <= ip->i_size)
@@ -306,12 +310,60 @@ xfs_iomap_eof_want_preallocate(
 				return 0;
 			start_fsb += imap[n].br_blockcount;
 			count_fsb -= imap[n].br_blockcount;
+
+			if (imap[n].br_startblock == DELAYSTARTBLOCK)
+				found_delalloc = 1;
 		}
 	}
-	*prealloc = 1;
+	if (!found_delalloc)
+		*prealloc = 1;
 	return 0;
 }
 
+/*
+ * If we don't have a user specified preallocation size, dynamically increase
+ * the preallocation size as the size of the file grows. Cap the maximum size
+ * at a single extent or less if the filesystem is near full. The closer the
+ * filesystem is to full, the smaller the maximum prealocation.
+ */
+STATIC xfs_fsblock_t
+xfs_iomap_prealloc_size(
+	struct xfs_mount	*mp,
+	struct xfs_inode	*ip)
+{
+	xfs_fsblock_t		alloc_blocks = 0;
+
+	if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE)) {
+		int shift = 0;
+		int64_t freesp;
+
+		alloc_blocks = XFS_B_TO_FSB(mp, ip->i_size);
+		alloc_blocks = XFS_FILEOFF_MIN(MAXEXTLEN,
+					rounddown_pow_of_two(alloc_blocks));
+
+		xfs_icsb_sync_counters(mp, XFS_ICSB_LAZY_COUNT);
+		freesp = mp->m_sb.sb_fdblocks;
+		if (freesp < mp->m_low_space[XFS_LOWSP_5_PCNT]) {
+			shift = 2;
+			if (freesp < mp->m_low_space[XFS_LOWSP_4_PCNT])
+				shift++;
+			if (freesp < mp->m_low_space[XFS_LOWSP_3_PCNT])
+				shift++;
+			if (freesp < mp->m_low_space[XFS_LOWSP_2_PCNT])
+				shift++;
+			if (freesp < mp->m_low_space[XFS_LOWSP_1_PCNT])
+				shift++;
+		}
+		if (shift)
+			alloc_blocks >>= shift;
+	}
+
+	if (alloc_blocks < mp->m_writeio_blocks)
+		alloc_blocks = mp->m_writeio_blocks;
+
+	return alloc_blocks;
+}
+
 int
 xfs_iomap_write_delay(
 	xfs_inode_t	*ip,
@@ -344,6 +396,7 @@ xfs_iomap_write_delay(
 	extsz = xfs_get_extsz_hint(ip);
 	offset_fsb = XFS_B_TO_FSBT(mp, offset);
 
+
 	error = xfs_iomap_eof_want_preallocate(mp, ip, offset, count,
 				imap, XFS_WRITE_IMAPS, &prealloc);
 	if (error)
@@ -351,9 +404,11 @@ xfs_iomap_write_delay(
 
 retry:
 	if (prealloc) {
+		xfs_fsblock_t	alloc_blocks = xfs_iomap_prealloc_size(mp, ip);
+
 		aligned_offset = XFS_WRITEIO_ALIGN(mp, (offset + count - 1));
 		ioalign = XFS_B_TO_FSBT(mp, aligned_offset);
-		last_fsb = ioalign + mp->m_writeio_blocks;
+		last_fsb = ioalign + alloc_blocks;
 	} else {
 		last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count)));
 	}
@@ -371,22 +426,31 @@ retry:
 			  XFS_BMAPI_DELAY | XFS_BMAPI_WRITE |
 			  XFS_BMAPI_ENTIRE, &firstblock, 1, imap,
 			  &nimaps, NULL);
-	if (error && (error != ENOSPC))
+	switch (error) {
+	case 0:
+	case ENOSPC:
+	case EDQUOT:
+		break;
+	default:
 		return XFS_ERROR(error);
+	}
 
 	/*
-	 * If bmapi returned us nothing, and if we didn't get back EDQUOT,
-	 * then we must have run out of space - flush all other inodes with
-	 * delalloc blocks and retry without EOF preallocation.
+	 * If bmapi returned us nothing, we got either ENOSPC or EDQUOT.  For
+	 * ENOSPC, * flush all other inodes with delalloc blocks to free up
+	 * some of the excess reserved metadata space. For both cases, retry
+	 * without EOF preallocation.
 	 */
 	if (nimaps == 0) {
 		trace_xfs_delalloc_enospc(ip, offset, count);
 		if (flushed)
-			return XFS_ERROR(ENOSPC);
+			return XFS_ERROR(error ? error : ENOSPC);
 
-		xfs_iunlock(ip, XFS_ILOCK_EXCL);
-		xfs_flush_inodes(ip);
-		xfs_ilock(ip, XFS_ILOCK_EXCL);
+		if (error == ENOSPC) {
+			xfs_iunlock(ip, XFS_ILOCK_EXCL);
+			xfs_flush_inodes(ip);
+			xfs_ilock(ip, XFS_ILOCK_EXCL);
+		}
 
 		flushed = 1;
 		error = 0;