Changes imported from XFS for FreeBSD project:

- add fields to struct buf (needed by XFS)
    - 3 private fields: b_fsprivate1, b_fsprivate2, b_fsprivate3
    - b_pin_count, count of pinned buffer

- add new B_MANAGED flag
- add breada() function to initiate asynchronous I/O on read-ahead blocks.
- add bufdone_finish(), bpin(), bunpin_wait() functions

Patches provided by:	kan
Reviewed by:		phk
Silence on:		arch@

1 files changed, 15 insertions, 0 deletions

diff --git a/sys/kern/vfs_cluster.c b/sys/kern/vfs_cluster.c
index 885f1f9..3266829 100644
--- a/sys/kern/vfs_cluster.c
+++ b/sys/kern/vfs_cluster.c
@@ -770,6 +770,12 @@ cluster_wbuild(vp, size, start_lbn, len)
 			--len;
 			continue;
 		}
+		if (tbp->b_pin_count >  0) {
+			BUF_UNLOCK(tbp);
+			++start_lbn;
+			--len;
+			continue;
+		}
 		bremfree(tbp);
 		tbp->b_flags &= ~B_DONE;
 
@@ -873,6 +879,15 @@ cluster_wbuild(vp, size, start_lbn, len)
 					BUF_UNLOCK(tbp);
 					break;
 				}
+
+				/*
+				 * Do not pull in pinned buffers.
+				 */
+				if (tbp->b_pin_count > 0) {
+					BUF_UNLOCK(tbp);
+					break;
+				}
+
 				/*
 				 * Ok, it's passed all the tests,
 				 * so remove it from the free list