[src/trunk]: src/sys/kern Add an operation to test a mount for fstrans suppor...

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

details:   https://anonhg.NetBSD.org/src/rev/34c06ecfac78
branches:  trunk
changeset: 351873:34c06ecfac78
user:      hannken <hannken%NetBSD.org@localhost>
date:      Thu Mar 02 10:41:27 2017 +0000

description:
Add an operation to test a mount for fstrans support and use it for
_fstrans_start(), fstrans_done(), fstrans_is_owner(), vfs_suspend()
and vfs_resume().

Test for fstrans support before ASSERT_SLEEPABLE().

diffstat:

 sys/kern/vfs_trans.c |  51 ++++++++++++++++++++++++++++++++++++---------------
 1 files changed, 36 insertions(+), 15 deletions(-)

diffs (130 lines):

diff -r 229ebc2802cd -r 34c06ecfac78 sys/kern/vfs_trans.c
--- a/sys/kern/vfs_trans.c      Thu Mar 02 09:48:20 2017 +0000
+++ b/sys/kern/vfs_trans.c      Thu Mar 02 10:41:27 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_trans.c,v 1.37 2017/02/23 11:23:22 hannken Exp $   */
+/*     $NetBSD: vfs_trans.c,v 1.38 2017/03/02 10:41:27 hannken Exp $   */
 
 /*-
  * Copyright (c) 2007 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_trans.c,v 1.37 2017/02/23 11:23:22 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_trans.c,v 1.38 2017/03/02 10:41:27 hannken Exp $");
 
 /*
  * File system transaction operations.
@@ -85,6 +85,7 @@
 static LIST_HEAD(fstrans_lwp_head, fstrans_lwp_info) fstrans_fli_head;
                                        /* List of all fstrans_lwp_info. */
 
+static inline struct mount *fstrans_normalize_mount(struct mount *);
 static void fstrans_lwp_dtor(void *);
 static void fstrans_mount_dtor(struct mount *);
 static struct fstrans_lwp_info *fstrans_get_lwp_info(struct mount *, bool);
@@ -115,6 +116,21 @@
 }
 
 /*
+ * Normalize mount.
+ * Return mount if file system supports fstrans, NULL otherwise.
+ */
+static inline struct mount *
+fstrans_normalize_mount(struct mount *mp)
+{
+
+       if (mp == NULL)
+               return NULL;
+       if ((mp->mnt_iflag & IMNT_HAS_TRANS) == 0)
+               return NULL;
+       return mp;
+}
+
+/*
  * Deallocate lwp state.
  */
 static void
@@ -199,6 +215,9 @@
 fstrans_unmount(struct mount *mp)
 {
 
+       if ((mp->mnt_iflag & IMNT_HAS_TRANS) == 0)
+               return;
+
        KASSERT(mp->mnt_transinfo != NULL);
 
        fstrans_mount_dtor(mp);
@@ -235,16 +254,6 @@
                return NULL;
 
        /*
-        * Does this file system support fstrans?
-        */
-       mutex_enter(&fstrans_mount_lock);
-       if ((mp->mnt_iflag & IMNT_HAS_TRANS) == 0) {
-               mutex_exit(&fstrans_mount_lock);
-               return NULL;
-       }
-       mutex_exit(&fstrans_mount_lock);
-
-       /*
         * Try to reuse a cleared entry or allocate a new one.
         */
        for (fli = lwp_getspecific(lwp_data_key); fli; fli = fli->fli_succ) {
@@ -321,9 +330,12 @@
        struct fstrans_lwp_info *fli;
        struct fstrans_mount_info *fmi;
 
+       if ((mp = fstrans_normalize_mount(mp)) == NULL)
+               return 0;
+
        ASSERT_SLEEPABLE();
 
-       if (mp == NULL || (fli = fstrans_get_lwp_info(mp, true)) == NULL)
+       if ((fli = fstrans_get_lwp_info(mp, true)) == NULL)
                return 0;
 
        if (fli->fli_trans_cnt > 0) {
@@ -367,7 +379,9 @@
        struct fstrans_lwp_info *fli;
        struct fstrans_mount_info *fmi;
 
-       if (mp == NULL || (fli = fstrans_get_lwp_info(mp, true)) == NULL)
+       if ((mp = fstrans_normalize_mount(mp)) == NULL)
+               return;
+       if ((fli = fstrans_get_lwp_info(mp, true)) == NULL)
                return;
 
        KASSERT(fli->fli_trans_cnt > 0);
@@ -402,7 +416,9 @@
 {
        struct fstrans_lwp_info *fli;
 
-       if (mp == NULL || (fli = fstrans_get_lwp_info(mp, false)) == NULL)
+       if ((mp = fstrans_normalize_mount(mp)) == NULL)
+               return 0;
+       if ((fli = fstrans_get_lwp_info(mp, false)) == NULL)
                return 0;
 
        if (fli->fli_trans_cnt == 0)
@@ -506,6 +522,8 @@
 {
        int error;
 
+       if ((mp = fstrans_normalize_mount(mp)) == NULL)
+               return EOPNOTSUPP;
        if (nowait) {
                if (!mutex_tryenter(&vfs_suspend_lock))
                        return EWOULDBLOCK;
@@ -525,6 +543,9 @@
 vfs_resume(struct mount *mp)
 {
 
+       mp = fstrans_normalize_mount(mp);
+       KASSERT(mp != NULL);
+               
        VFS_SUSPENDCTL(mp, SUSPEND_RESUME);
        mutex_exit(&vfs_suspend_lock);
 }