Author: mjg
Date: Sun Oct 19 06:59:33 2014
New Revision: 273271
URL: https://svnweb.freebsd.org/changeset/base/273271
Log:
Provide vfs suspension support only for filesystems which need it.
Need is expressed by providing vfs_susp_clean function in vfsops.
Differential Revision: D952
Reviewed by: kib (previous version)
MFC after: 2 weeks
Modified:
head/sys/fs/tmpfs/tmpfs_vfsops.c
head/sys/kern/vfs_vnops.c
head/sys/sys/mount.h
Modified: head/sys/fs/tmpfs/tmpfs_vfsops.c
==============================================================================
--- head/sys/fs/tmpfs/tmpfs_vfsops.c Sun Oct 19 04:38:02 2014
(r273270)
+++ head/sys/fs/tmpfs/tmpfs_vfsops.c Sun Oct 19 06:59:33 2014
(r273271)
@@ -427,6 +427,14 @@ tmpfs_sync(struct mount *mp, int waitfor
}
/*
+ * A stub created so that vfs does vn_start_write for this filesystem
+ */
+static void
+tmpfs_susp_clean(struct mount *mp)
+{
+}
+
+/*
* tmpfs vfs operations.
*/
@@ -437,5 +445,6 @@ struct vfsops tmpfs_vfsops = {
.vfs_statfs = tmpfs_statfs,
.vfs_fhtovp = tmpfs_fhtovp,
.vfs_sync = tmpfs_sync,
+ .vfs_susp_clean = tmpfs_susp_clean,
};
VFS_SET(tmpfs_vfsops, tmpfs, VFCF_JAIL);
Modified: head/sys/kern/vfs_vnops.c
==============================================================================
--- head/sys/kern/vfs_vnops.c Sun Oct 19 04:38:02 2014 (r273270)
+++ head/sys/kern/vfs_vnops.c Sun Oct 19 06:59:33 2014 (r273271)
@@ -1572,6 +1572,25 @@ vn_closefile(fp, td)
return (error);
}
+static bool
+vn_suspendable_mp(struct mount *mp)
+{
+
+ return (mp->mnt_op->vfs_susp_clean != NULL);
+}
+
+static bool
+vn_suspendable(struct vnode *vp, struct mount **mpp)
+{
+
+ if (vp != NULL)
+ *mpp = vp->v_mount;
+ if (*mpp == NULL)
+ return (false);
+
+ return (vn_suspendable_mp(*mpp));
+}
+
/*
* Preparing to start a filesystem write operation. If the operation is
* permitted, then we bump the count of operations in progress and
@@ -1621,6 +1640,9 @@ vn_start_write(vp, mpp, flags)
struct mount *mp;
int error;
+ if (!vn_suspendable(vp, mpp))
+ return (0);
+
error = 0;
/*
* If a vnode is provided, get and return the mount point that
@@ -1667,6 +1689,9 @@ vn_start_secondary_write(vp, mpp, flags)
struct mount *mp;
int error;
+ if (!vn_suspendable(vp, mpp))
+ return (0);
+
retry:
if (vp != NULL) {
if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) {
@@ -1724,7 +1749,7 @@ void
vn_finished_write(mp)
struct mount *mp;
{
- if (mp == NULL)
+ if (mp == NULL || !vn_suspendable_mp(mp))
return;
MNT_ILOCK(mp);
MNT_REL(mp);
@@ -1747,7 +1772,7 @@ void
vn_finished_secondary_write(mp)
struct mount *mp;
{
- if (mp == NULL)
+ if (mp == NULL || !vn_suspendable_mp(mp))
return;
MNT_ILOCK(mp);
MNT_REL(mp);
@@ -1770,6 +1795,8 @@ vfs_write_suspend(struct mount *mp, int
{
int error;
+ MPASS(vn_suspendable_mp(mp));
+
MNT_ILOCK(mp);
if (mp->mnt_susp_owner == curthread) {
MNT_IUNLOCK(mp);
@@ -1811,6 +1838,8 @@ void
vfs_write_resume(struct mount *mp, int flags)
{
+ MPASS(vn_suspendable_mp(mp));
+
MNT_ILOCK(mp);
if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner"));
@@ -1844,6 +1873,7 @@ vfs_write_suspend_umnt(struct mount *mp)
{
int error;
+ MPASS(vn_suspendable_mp(mp));
KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0,
("vfs_write_suspend_umnt: recursed"));
Modified: head/sys/sys/mount.h
==============================================================================
--- head/sys/sys/mount.h Sun Oct 19 04:38:02 2014 (r273270)
+++ head/sys/sys/mount.h Sun Oct 19 06:59:33 2014 (r273271)
@@ -754,11 +754,10 @@ vfs_statfs_t __vfs_statfs;
_rc; })
#define VFS_SUSP_CLEAN(MP) do {
\
- if (*(MP)->mnt_op->vfs_susp_clean != NULL) { \
- VFS_PROLOGUE(MP); \
- (*(MP)->mnt_op->vfs_susp_clean)(MP); \
- VFS_EPILOGUE(MP); \
- } \
+ MPASS(*(MP)->mnt_op->vfs_susp_clean != NULL); \
+ VFS_PROLOGUE(MP); \
+ (*(MP)->mnt_op->vfs_susp_clean)(MP); \
+ VFS_EPILOGUE(MP); \
} while (0)
#define VFS_RECLAIM_LOWERVP(MP, VP) do {
\
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