git: d0929a990c80 - main - ffs: reduce number of dvp relocks in softdep_prelink()

[Konstantin Belousov]

The branch main has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=d0929a990c80b78bc84326234cf54cd4382d42fd

commit d0929a990c80b78bc84326234cf54cd4382d42fd
Author:     Konstantin Belousov <kib at FreeBSD.org>
AuthorDate: 2021-04-29 22:21:33 +0000
Commit:     Konstantin Belousov <kib at FreeBSD.org>
CommitDate: 2021-06-23 20:46:15 +0000

    ffs: reduce number of dvp relocks in softdep_prelink()
    
    If vp == NULL, we unlocked and then immediately relocked dvp there.
    
    Reviewed by:    mckusick
    Discussed with: markj
    Tested by:      pho
    Sponsored by:   The FreeBSD Foundation
    MFC after:      2 weeks
    Differential revision:  https://reviews.freebsd.org/D30041
---
 sys/ufs/ffs/ffs_softdep.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/sys/ufs/ffs/ffs_softdep.c b/sys/ufs/ffs/ffs_softdep.c
index 23c0cf6e128b..2a76ec41f03d 100644
--- a/sys/ufs/ffs/ffs_softdep.c
+++ b/sys/ufs/ffs/ffs_softdep.c
@@ -3415,10 +3415,9 @@ softdep_prelink(dvp, vp)
 	if (vp != NULL)
 		VOP_UNLOCK(vp);
 	ffs_syncvnode(dvp, MNT_WAIT, 0);
-	VOP_UNLOCK(dvp);
-
 	/* Process vp before dvp as it may create .. removes. */
 	if (vp != NULL) {
+		VOP_UNLOCK(dvp);
 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 		if (vp->v_data == NULL) {
 			vn_lock_pair(dvp, false, vp, true);
@@ -3429,12 +3428,11 @@ softdep_prelink(dvp, vp)
 		process_truncates(vp);
 		FREE_LOCK(ump);
 		VOP_UNLOCK(vp);
-	}
-
-	vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
-	if (dvp->v_data == NULL) {
-		vn_lock_pair(dvp, true, vp, false);
-		return (ERELOOKUP);
+		vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
+		if (dvp->v_data == NULL) {
+			vn_lock_pair(dvp, true, vp, false);
+			return (ERELOOKUP);
+		}
 	}
 
 	ACQUIRE_LOCK(ump);