[DragonFlyBSD - Submit #2471] [PATCH] kernel -- ffs: Fix soft updates MKDIR_BODY buffer processing panic.

[Venkatesh Srinivas via Redmine]

Issue #2471 has been reported by Venkatesh Srinivas.

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Submit #2471: [PATCH] kernel -- ffs: Fix soft updates MKDIR_BODY buffer processing panic.
http://bugs.dragonflybsd.org/issues/2471

Author: Venkatesh Srinivas
Status: New
Priority: Normal
Assignee: 
Category: 
Target version: 


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)."
---
  sys/vfs/ufs/ffs_softdep.c |   26 ++++++++++++++++++++++++++
  1 files changed, 26 insertions(+), 0 deletions(-)

diff --git a/sys/vfs/ufs/ffs_softdep.c b/sys/vfs/ufs/ffs_softdep.c
index 942245c..d2e43b6 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.
-- 
1.7.7.2


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