git: 4dcdf3987c1c - main - vfs: replace the MNTK_TEXT_REFS flag with VIRF_TEXT_REF
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Date: Sat, 27 Nov 2021 23:19:31 UTC
The branch main has been updated by mjg:
URL: https://cgit.FreeBSD.org/src/commit/?id=4dcdf3987c1cc95d0d344468e8aa15452254691c
commit 4dcdf3987c1cc95d0d344468e8aa15452254691c
Author: Mateusz Guzik <mjg@FreeBSD.org>
AuthorDate: 2021-05-18 10:47:21 +0000
Commit: Mateusz Guzik <mjg@FreeBSD.org>
CommitDate: 2021-11-27 23:07:25 +0000
vfs: replace the MNTK_TEXT_REFS flag with VIRF_TEXT_REF
This allows to stop maintaing the VI_TEXT_REF flag and consequently
opens up fully lockless v_writecount adjustment.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D33127
---
sys/fs/tmpfs/tmpfs_subr.c | 2 +-
sys/fs/tmpfs/tmpfs_vfsops.c | 2 +-
sys/kern/vfs_default.c | 20 +++++++++-----------
sys/kern/vfs_subr.c | 8 ++++----
sys/sys/mount.h | 2 +-
sys/sys/vnode.h | 3 ++-
6 files changed, 18 insertions(+), 19 deletions(-)
diff --git a/sys/fs/tmpfs/tmpfs_subr.c b/sys/fs/tmpfs/tmpfs_subr.c
index 9810c1776314..41d9b6d5dcca 100644
--- a/sys/fs/tmpfs/tmpfs_subr.c
+++ b/sys/fs/tmpfs/tmpfs_subr.c
@@ -967,7 +967,7 @@ loop:
vp->v_object = object;
object->un_pager.swp.swp_tmpfs = vp;
vm_object_set_flag(object, OBJ_TMPFS);
- vn_irflag_set_locked(vp, VIRF_PGREAD);
+ vn_irflag_set_locked(vp, VIRF_PGREAD | VIRF_TEXT_REF);
VI_UNLOCK(vp);
VM_OBJECT_WUNLOCK(object);
break;
diff --git a/sys/fs/tmpfs/tmpfs_vfsops.c b/sys/fs/tmpfs/tmpfs_vfsops.c
index b8ecedbb0348..7bd44decd830 100644
--- a/sys/fs/tmpfs/tmpfs_vfsops.c
+++ b/sys/fs/tmpfs/tmpfs_vfsops.c
@@ -469,7 +469,7 @@ tmpfs_mount(struct mount *mp)
MNT_ILOCK(mp);
mp->mnt_flag |= MNT_LOCAL;
mp->mnt_kern_flag |= MNTK_LOOKUP_SHARED | MNTK_EXTENDED_SHARED |
- MNTK_TEXT_REFS | MNTK_NOMSYNC;
+ MNTK_NOMSYNC;
if (!nonc && (mp->mnt_flag & MNT_UNION) == 0)
mp->mnt_kern_flag |= MNTK_FPLOOKUP;
MNT_IUNLOCK(mp);
diff --git a/sys/kern/vfs_default.c b/sys/kern/vfs_default.c
index 50829ad3044e..1f5869bd8cf3 100644
--- a/sys/kern/vfs_default.c
+++ b/sys/kern/vfs_default.c
@@ -1300,7 +1300,6 @@ int
vop_stdset_text(struct vop_set_text_args *ap)
{
struct vnode *vp;
- struct mount *mp;
int error, n;
vp = ap->a_vp;
@@ -1326,12 +1325,10 @@ vop_stdset_text(struct vop_set_text_args *ap)
* If requested by fs, keep a use reference to the
* vnode until the last text reference is released.
*/
- mp = vp->v_mount;
- if (mp != NULL && (mp->mnt_kern_flag & MNTK_TEXT_REFS) != 0 &&
- vp->v_writecount == 0) {
- VNPASS((vp->v_iflag & VI_TEXT_REF) == 0, vp);
- vp->v_iflag |= VI_TEXT_REF;
- vrefl(vp);
+ if ((vn_irflag_read(vp) & VIRF_TEXT_REF) != 0) {
+ if (vp->v_writecount == 0) {
+ vrefl(vp);
+ }
}
atomic_subtract_int(&vp->v_writecount, 1);
@@ -1366,11 +1363,12 @@ vop_stdunset_text(struct vop_unset_text_args *ap)
last = false;
VI_LOCK(vp);
if (vp->v_writecount < 0) {
- if ((vp->v_iflag & VI_TEXT_REF) != 0 &&
- vp->v_writecount == -1) {
- last = true;
- vp->v_iflag &= ~VI_TEXT_REF;
+ if ((vn_irflag_read(vp) & VIRF_TEXT_REF) != 0) {
+ if (vp->v_writecount == -1) {
+ last = true;
+ }
}
+
atomic_add_int(&vp->v_writecount, 1);
error = 0;
} else {
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index 65a9ebf304fe..06ca5dc7d93a 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -4122,7 +4122,9 @@ vn_printf(struct vnode *vp, const char *fmt, ...)
strlcat(buf, "|VIRF_PGREAD", sizeof(buf));
if (irflag & VIRF_MOUNTPOINT)
strlcat(buf, "|VIRF_MOUNTPOINT", sizeof(buf));
- flags = irflag & ~(VIRF_DOOMED | VIRF_PGREAD | VIRF_MOUNTPOINT);
+ if (irflag & VIRF_TEXT_REF)
+ strlcat(buf, "|VIRF_TEXT_REF", sizeof(buf));
+ flags = irflag & ~(VIRF_DOOMED | VIRF_PGREAD | VIRF_MOUNTPOINT | VIRF_TEXT_REF);
if (flags != 0) {
snprintf(buf2, sizeof(buf2), "|VIRF(0x%lx)", flags);
strlcat(buf, buf2, sizeof(buf));
@@ -4163,8 +4165,6 @@ vn_printf(struct vnode *vp, const char *fmt, ...)
snprintf(buf2, sizeof(buf2), "|VV(0x%lx)", flags);
strlcat(buf, buf2, sizeof(buf));
}
- if (vp->v_iflag & VI_TEXT_REF)
- strlcat(buf, "|VI_TEXT_REF", sizeof(buf));
if (vp->v_iflag & VI_MOUNT)
strlcat(buf, "|VI_MOUNT", sizeof(buf));
if (vp->v_iflag & VI_DOINGINACT)
@@ -4175,7 +4175,7 @@ vn_printf(struct vnode *vp, const char *fmt, ...)
strlcat(buf, "|VI_DEFINACT", sizeof(buf));
if (vp->v_iflag & VI_FOPENING)
strlcat(buf, "|VI_FOPENING", sizeof(buf));
- flags = vp->v_iflag & ~(VI_TEXT_REF | VI_MOUNT | VI_DOINGINACT |
+ flags = vp->v_iflag & ~(VI_MOUNT | VI_DOINGINACT |
VI_OWEINACT | VI_DEFINACT | VI_FOPENING);
if (flags != 0) {
snprintf(buf2, sizeof(buf2), "|VI(0x%lx)", flags);
diff --git a/sys/sys/mount.h b/sys/sys/mount.h
index 1863a36738d1..d47d67f1156b 100644
--- a/sys/sys/mount.h
+++ b/sys/sys/mount.h
@@ -489,7 +489,7 @@ struct mntoptnames {
#define MNTK_LOOKUP_EXCL_DOTDOT 0x00000800
#define MNTK_UNMAPPED_BUFS 0x00002000
#define MNTK_USES_BCACHE 0x00004000 /* FS uses the buffer cache. */
-#define MNTK_TEXT_REFS 0x00008000 /* Keep use ref for text */
+#define MNTK_UNUSED0 0x00008000 /* unused */
#define MNTK_VMSETSIZE_BUG 0x00010000
#define MNTK_UNIONFS 0x00020000 /* A hack for F_ISUNIONSTACK */
#define MNTK_FPLOOKUP 0x00040000 /* fast path lookup is supported */
diff --git a/sys/sys/vnode.h b/sys/sys/vnode.h
index c84d015b011c..53b0a45064b9 100644
--- a/sys/sys/vnode.h
+++ b/sys/sys/vnode.h
@@ -251,8 +251,9 @@ struct xvnode {
#define VIRF_PGREAD 0x0002 /* Direct reads from the page cache are permitted,
never cleared once set */
#define VIRF_MOUNTPOINT 0x0004 /* This vnode is mounted on */
+#define VIRF_TEXT_REF 0x0008 /* Executable mappings ref the vnode */
-#define VI_TEXT_REF 0x0001 /* Text ref grabbed use ref */
+#define VI_UNUSED0 0x0001 /* unused */
#define VI_MOUNT 0x0002 /* Mount in progress */
#define VI_DOINGINACT 0x0004 /* VOP_INACTIVE is in progress */
#define VI_OWEINACT 0x0008 /* Need to call inactive */