[src/trunk]: src/sys/ufs/lfs Serialize access to the splay tree with lfs_lock.

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/993452ea0c22
branches:  trunk
changeset: 745128:993452ea0c22
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sun Feb 23 08:39:48 2020 +0000

description:
Serialize access to the splay tree with lfs_lock.

diffstat:

 sys/ufs/lfs/lfs_balloc.c |  29 ++++++++++++++++-------------
 1 files changed, 16 insertions(+), 13 deletions(-)

diffs (81 lines):

diff -r 205bbe966303 -r 993452ea0c22 sys/ufs/lfs/lfs_balloc.c
--- a/sys/ufs/lfs/lfs_balloc.c  Sun Feb 23 08:39:39 2020 +0000
+++ b/sys/ufs/lfs/lfs_balloc.c  Sun Feb 23 08:39:48 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: lfs_balloc.c,v 1.94 2017/06/10 05:29:36 maya Exp $     */
+/*     $NetBSD: lfs_balloc.c,v 1.95 2020/02/23 08:39:48 riastradh Exp $        */
 
 /*-
  * Copyright (c) 1999, 2000, 2001, 2002, 2003 The NetBSD Foundation, Inc.
@@ -60,7 +60,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: lfs_balloc.c,v 1.94 2017/06/10 05:29:36 maya Exp $");
+__KERNEL_RCSID(0, "$NetBSD: lfs_balloc.c,v 1.95 2020/02/23 08:39:48 riastradh Exp $");
 
 #if defined(_KERNEL_OPT)
 #include "opt_quota.h"
@@ -660,9 +660,10 @@
 static void
 lfs_do_deregister(struct lfs *fs, struct inode *ip, struct lbnentry *lbp)
 {
+
+       KASSERT(mutex_owned(&lfs_lock));
        ASSERT_MAYBE_SEGLOCK(fs);
 
-       mutex_enter(&lfs_lock);
        --ip->i_lfs_nbtree;
        SPLAY_REMOVE(lfs_splay, &ip->i_lfs_lbtree, lbp);
        if (fs->lfs_favail > lfs_btofsb(fs, (1 << lfs_sb_getbshift(fs))))
@@ -671,9 +672,12 @@
        if (locked_fakequeue_count > 0)
                --locked_fakequeue_count;
        lfs_subsys_pages -= lfs_sb_getbsize(fs) >> PAGE_SHIFT;
-       mutex_exit(&lfs_lock);
 
+       mutex_exit(&lfs_lock);
        pool_put(&lfs_lbnentry_pool, lbp);
+       mutex_enter(&lfs_lock);
+
+       KASSERT(mutex_owned(&lfs_lock));
 }
 
 void
@@ -690,19 +694,18 @@
        if (lbn < 0 || vp->v_type != VREG || ip->i_number == LFS_IFILE_INUM)
                return;
 
+       mutex_enter(&lfs_lock);
        fs = ip->i_lfs;
        tmp.lbn = lbn;
-       lbp = SPLAY_FIND(lfs_splay, &ip->i_lfs_lbtree, &tmp);
-       if (lbp == NULL)
-               return;
-
-       lfs_do_deregister(fs, ip, lbp);
+       if ((lbp = SPLAY_FIND(lfs_splay, &ip->i_lfs_lbtree, &tmp)) != NULL)
+               lfs_do_deregister(fs, ip, lbp);
+       mutex_exit(&lfs_lock);
 }
 
 void
 lfs_deregister_all(struct vnode *vp)
 {
-       struct lbnentry *lbp, *nlbp;
+       struct lbnentry *lbp;
        struct lfs_splay *hd;
        struct lfs *fs;
        struct inode *ip;
@@ -711,8 +714,8 @@
        fs = ip->i_lfs;
        hd = &ip->i_lfs_lbtree;
 
-       for (lbp = SPLAY_MIN(lfs_splay, hd); lbp != NULL; lbp = nlbp) {
-               nlbp = SPLAY_NEXT(lfs_splay, hd, lbp);
+       mutex_enter(&lfs_lock);
+       while ((lbp = SPLAY_MIN(lfs_splay, hd)) != NULL)
                lfs_do_deregister(fs, ip, lbp);
-       }
+       mutex_exit(&lfs_lock);
 }