Reorganize softdep_fsync so that it only does the inode-is-flushed

check before the inode is unlocked while grabbing its parent directory.
Once it is unlocked, other operations may slip in that could make
the inode-is-flushed check fail. Allowing other writes to the inode
before returning from fsync does not break the semantics of fsync
since we have flushed everything that was dirty at the time of the
fsync call.

1 files changed, 22 insertions, 26 deletions

diff --git a/sys/ufs/ffs/ffs_softdep.c b/sys/ufs/ffs/ffs_softdep.c
index 396cd48..fde758b 100644
--- a/sys/ufs/ffs/ffs_softdep.c
+++ b/sys/ufs/ffs/ffs_softdep.c
@@ -52,7 +52,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	from: @(#)ffs_softdep.c	9.43 (McKusick) 1/9/00
+ *	from: @(#)ffs_softdep.c	9.44 (McKusick) 1/9/00
  * $FreeBSD$
  */
 
@@ -3587,31 +3587,33 @@ static int
 softdep_fsync(vp)
 	struct vnode *vp;	/* the "in_core" copy of the inode */
 {
-	struct diradd *dap, *olddap;
 	struct inodedep *inodedep;
 	struct pagedep *pagedep;
 	struct worklist *wk;
+	struct diradd *dap;
 	struct mount *mnt;
 	struct vnode *pvp;
 	struct inode *ip;
 	struct buf *bp;
 	struct fs *fs;
 	struct proc *p = CURPROC;		/* XXX */
-	int error, ret, flushparent;
+	int error, flushparent;
 	ino_t parentino;
 	ufs_lbn_t lbn;
 
 	ip = VTOI(vp);
 	fs = ip->i_fs;
-	for (error = 0, flushparent = 0, olddap = NULL; ; ) {
-		ACQUIRE_LOCK(&lk);
-		if (inodedep_lookup(fs, ip->i_number, 0, &inodedep) == 0)
-			break;
-		if (LIST_FIRST(&inodedep->id_inowait) != NULL ||
-		    LIST_FIRST(&inodedep->id_bufwait) != NULL ||
-		    TAILQ_FIRST(&inodedep->id_inoupdt) != NULL ||
-		    TAILQ_FIRST(&inodedep->id_newinoupdt) != NULL)
-			panic("softdep_fsync: pending ops");
+	ACQUIRE_LOCK(&lk);
+	if (inodedep_lookup(fs, ip->i_number, 0, &inodedep) == 0) {
+		FREE_LOCK(&lk);
+		return (0);
+	}
+	if (LIST_FIRST(&inodedep->id_inowait) != NULL ||
+	    LIST_FIRST(&inodedep->id_bufwait) != NULL ||
+	    TAILQ_FIRST(&inodedep->id_inoupdt) != NULL ||
+	    TAILQ_FIRST(&inodedep->id_newinoupdt) != NULL)
+		panic("softdep_fsync: pending ops");
+	for (error = 0, flushparent = 0; ; ) {
 		if ((wk = LIST_FIRST(&inodedep->id_pendinghd)) == NULL)
 			break;
 		if (wk->wk_type != D_DIRADD)
@@ -3619,13 +3621,6 @@ softdep_fsync(vp)
 			    TYPENAME(wk->wk_type));
 		dap = WK_DIRADD(wk);
 		/*
-		 * If we have failed to get rid of all the dependencies
-		 * then something is seriously wrong.
-		 */
-		if (dap == olddap)
-			panic("softdep_fsync: flush failed");
-		olddap = dap;
-		/*
 		 * Flush our parent if this directory entry
 		 * has a MKDIR_PARENT dependency.
 		 */
@@ -3658,11 +3653,10 @@ softdep_fsync(vp)
 		 */
 		FREE_LOCK(&lk);
 		VOP_UNLOCK(vp, 0, p);
-		if ((error = VFS_VGET(mnt, parentino, &pvp)) != 0) {
-			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
-			return (error);
-		}
+		error = VFS_VGET(mnt, parentino, &pvp);
 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
+		if (error != 0)
+			return (error);
 		if (flushparent) {
 			if ((error = UFS_UPDATE(pvp, 1)) != 0) {
 				vput(pvp);
@@ -3674,12 +3668,14 @@ softdep_fsync(vp)
 		 */
 		error = bread(pvp, lbn, blksize(fs, VTOI(pvp), lbn), p->p_ucred,
 		    &bp);
-		ret = VOP_BWRITE(bp->b_vp, bp);
+		if (error == 0)
+			error = VOP_BWRITE(bp->b_vp, bp);
 		vput(pvp);
 		if (error != 0)
 			return (error);
-		if (ret != 0)
-			return (ret);
+		ACQUIRE_LOCK(&lk);
+		if (inodedep_lookup(fs, ip->i_number, 0, &inodedep) == 0)
+			break;
 	}
 	FREE_LOCK(&lk);
 	return (0);