[XFS] fix writeback control handling fix a reversed condition on where to

trylock and deal with block layer congestion properly.	Patch from David
Chinner and Christoph Hellwig.

SGI-PV: 947118
SGI-Modid: xfs-linux-melb:xfs-kern:203830a

Signed-off-by: Christoph Hellwig <hch@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>

1 files changed, 12 insertions, 3 deletions

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index 9ea33ea6a225..52707b5ddcb8 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -722,8 +722,17 @@ xfs_convert_page(
                 SetPageUptodate(page);
 
         if (startio) {
-                if (count)
-                        wbc->nr_to_write--;
+                if (count) {
+                        struct backing_dev_info *bdi;
+
+                        bdi = inode->i_mapping->backing_dev_info;
+                        if (bdi_write_congested(bdi)) {
+                                wbc->encountered_congestion = 1;
+                                done = 1;
+                        } else if (--wbc->nr_to_write <= 0) {
+                                done = 1;
+                        }
+                }
                 xfs_start_page_writeback(page, wbc, !page_dirty, count);
         }
 
@@ -812,7 +821,7 @@ xfs_page_state_convert(
         int                     all_bh = unmapped;
 
         /* wait for other IO threads? */
-        if (startio && wbc->sync_mode != WB_SYNC_NONE)
+        if (startio && (wbc->sync_mode == WB_SYNC_NONE && wbc->nonblocking))
                 trylock_flag |= BMAPI_TRYLOCK;
 
         /* Is this page beyond the end of the file? */