From: Matthew Dillon <dillon@apollo.backplane.com>
Date: Fri, 14 Dec 2012 21:05:00 +0000 (-0800)
Subject: kernel - ufs softdep fix under heavy load
X-Git-Tag: v3.4.0rc~672
X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/01a04a60873088916e4c5bcd230359c3ca654a9d

kernel - ufs softdep fix under heavy load

Fix is from OpenBSD ffs_softdep.c v1.79, originally from FreeBSD
ffs_softdep.c 1.196. Commit message from OpenBSD:

"due to ffs_sync not be able to sync some buffers here is another
instance of softdep code that must ensure proper syncing.
try harder to flush MKDIR_BODY dependancy if such still exists
during pagedep flush (that is by syncing first block of the dir)."
---

diff --git a/sys/vfs/ufs/ffs_softdep.c b/sys/vfs/ufs/ffs_softdep.c
index 942245cb5f..d2e43b6272 100644
--- a/sys/vfs/ufs/ffs_softdep.c
+++ b/sys/vfs/ufs/ffs_softdep.c
@@ -4527,6 +4527,7 @@ flush_pagedep_deps(struct vnode *pvp, struct mount *mp,
 	struct inodedep *inodedep;
 	struct ufsmount *ump;
 	struct diradd *dap;
+	struct worklist *wk;
 	struct vnode *vp;
 	int gotit, error = 0;
 	struct buf *bp;
@@ -4575,7 +4576,32 @@ flush_pagedep_deps(struct vnode *pvp, struct mount *mp,
 				break;
 			}
 			drain_output(vp, 0);
+			/*
+			 * If first block is still dirty with a D_MKDIR
+			 * dependency then it needs to be written now.
+			 */
+			error = 0;
+			ACQUIRE_LOCK(&lk);
+			bp = findblk(vp, 0, FINDBLK_TEST);
+			if (bp == NULL) {
+				FREE_LOCK(&lk);
+				goto mkdir_body_continue;
+			}
+			LIST_FOREACH(wk, &bp->b_dep, wk_list)
+				if (wk->wk_type == D_MKDIR) {
+					gotit = getdirtybuf(&bp, MNT_WAIT);
+					FREE_LOCK(&lk);
+					if (gotit && (error = bwrite(bp)) != 0)
+						goto mkdir_body_continue;
+					break;
+				}
+			if (wk == NULL)
+				FREE_LOCK(&lk);
+		mkdir_body_continue:
 			vput(vp);
+			/* Flushing of first block failed. */
+			if (error)
+				break;
 			ACQUIRE_LOCK(&lk);
 			/*
 			 * If that cleared dependencies, go on to next.