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[src/trunk]: src/sys/kern - Make the fstrans mount info part of the per-lwp s...
details: https://anonhg.NetBSD.org/src/rev/c94c96907835
branches: trunk
changeset: 997074:c94c96907835
user: hannken <hannken%NetBSD.org@localhost>
date: Wed Feb 20 10:09:45 2019 +0000
description:
- Make the fstrans mount info part of the per-lwp state and replace
most accesses to the mount with fstrans mount info.
- Add "fmi_gone" to be true after unmount and add a counter of
outstanding mount infos so fstrans_clear_lwp_info() only runs
if there may be something to do.
- Move lookup of base mounts into per-lwp state.
- Keep a list of valid mounts for DIAGNOSTIC checks.
diffstat:
sys/kern/vfs_trans.c | 338 +++++++++++++++++++++++++++++++-------------------
1 files changed, 209 insertions(+), 129 deletions(-)
diffs (truncated from 699 to 300 lines):
diff -r 65528c82f1e2 -r c94c96907835 sys/kern/vfs_trans.c
--- a/sys/kern/vfs_trans.c Wed Feb 20 10:08:37 2019 +0000
+++ b/sys/kern/vfs_trans.c Wed Feb 20 10:09:45 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: vfs_trans.c,v 1.53 2019/02/20 10:08:37 hannken Exp $ */
+/* $NetBSD: vfs_trans.c,v 1.54 2019/02/20 10:09:45 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 1.53 2019/02/20 10:08:37 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_trans.c,v 1.54 2019/02/20 10:09:45 hannken Exp $");
/*
* File system transaction operations.
@@ -68,6 +68,8 @@
struct fstrans_lwp_info *fli_succ;
struct lwp *fli_self;
struct mount *fli_mount;
+ struct mount *fli_alias;
+ struct fstrans_mount_info *fli_mountinfo;
int fli_trans_cnt;
int fli_cow_cnt;
enum fstrans_lock_type fli_lock_type;
@@ -76,8 +78,10 @@
struct fstrans_mount_info {
enum fstrans_state fmi_state;
unsigned int fmi_ref_cnt;
+ bool fmi_gone;
bool fmi_cow_change;
LIST_HEAD(, fscow_handler) fmi_cow_handler;
+ struct mount *fmi_mount;
};
static specificdata_key_t lwp_data_key; /* Our specific data key. */
@@ -89,23 +93,87 @@
static pserialize_t fstrans_psz; /* Pserialize state. */
static LIST_HEAD(fstrans_lwp_head, fstrans_lwp_info) fstrans_fli_head;
/* List of all fstrans_lwp_info. */
+static int fstrans_gone_count; /* Number of fstrans_mount_info gone. */
-static inline struct mount *fstrans_normalize_mount(struct mount *);
static void fstrans_lwp_dtor(void *);
-static void fstrans_mount_dtor(struct mount *);
+static void fstrans_mount_dtor(struct fstrans_mount_info *);
static void fstrans_clear_lwp_info(void);
static inline struct fstrans_lwp_info *
fstrans_get_lwp_info(struct mount *, bool);
static struct fstrans_lwp_info *fstrans_alloc_lwp_info(struct mount *);
static inline int _fstrans_start(struct mount *, enum fstrans_lock_type, int);
static bool grant_lock(const enum fstrans_state, const enum fstrans_lock_type);
-static bool state_change_done(const struct mount *);
-static bool cow_state_change_done(const struct mount *);
-static void cow_change_enter(const struct mount *);
-static void cow_change_done(const struct mount *);
+static bool state_change_done(const struct fstrans_mount_info *);
+static bool cow_state_change_done(const struct fstrans_mount_info *);
+static void cow_change_enter(struct fstrans_mount_info *);
+static void cow_change_done(struct fstrans_mount_info *);
extern struct mount *dead_rootmount;
+#if defined(DIAGNOSTIC)
+
+struct fstrans_debug_mount {
+ struct mount *fdm_mount;
+ SLIST_ENTRY(fstrans_debug_mount) fdm_list;
+};
+
+static SLIST_HEAD(, fstrans_debug_mount) fstrans_debug_mount_head =
+ SLIST_HEAD_INITIALIZER(fstrans_debug_mount_head);
+
+static void
+fstrans_debug_mount(struct mount *mp)
+{
+ struct fstrans_debug_mount *fdm, *new;
+
+ KASSERT(mutex_owned(&fstrans_mount_lock));
+
+ mutex_exit(&fstrans_mount_lock);
+ new = kmem_alloc(sizeof(*new), KM_SLEEP);
+ new->fdm_mount = mp;
+ mutex_enter(&fstrans_mount_lock);
+
+ SLIST_FOREACH(fdm, &fstrans_debug_mount_head, fdm_list)
+ KASSERT(fdm->fdm_mount != mp);
+ SLIST_INSERT_HEAD(&fstrans_debug_mount_head, new, fdm_list);
+}
+
+static void
+fstrans_debug_unmount(struct mount *mp)
+{
+ struct fstrans_debug_mount *fdm;
+
+ KASSERT(mutex_owned(&fstrans_mount_lock));
+
+ SLIST_FOREACH(fdm, &fstrans_debug_mount_head, fdm_list)
+ if (fdm->fdm_mount == mp)
+ break;
+ KASSERT(fdm != NULL);
+ SLIST_REMOVE(&fstrans_debug_mount_head, fdm,
+ fstrans_debug_mount, fdm_list);
+ kmem_free(fdm, sizeof(*fdm));
+}
+
+static void
+fstrans_debug_validate_mount(struct mount *mp)
+{
+ struct fstrans_debug_mount *fdm;
+
+ KASSERT(mutex_owned(&fstrans_mount_lock));
+
+ SLIST_FOREACH(fdm, &fstrans_debug_mount_head, fdm_list)
+ if (fdm->fdm_mount == mp)
+ break;
+ KASSERTMSG(fdm != NULL, "mount %p invalid", mp);
+}
+
+#else /* defined(DIAGNOSTIC) */
+
+#define fstrans_debug_mount(mp)
+#define fstrans_debug_unmount(mp)
+#define fstrans_debug_validate_mount(mp)
+
+#endif /* defined(DIAGNOSTIC) */
+
/*
* Initialize.
*/
@@ -127,21 +195,6 @@
}
/*
- * Normalize mount.
- * Return mount if file system supports fstrans, NULL otherwise.
- */
-static inline struct mount *
-fstrans_normalize_mount(struct mount *mp)
-{
-
- while (mp && mp->mnt_lower)
- mp = mp->mnt_lower;
- if (mp == NULL)
- return NULL;
- return mp;
-}
-
-/*
* Deallocate lwp state.
*/
static void
@@ -153,9 +206,11 @@
KASSERT(fli->fli_trans_cnt == 0);
KASSERT(fli->fli_cow_cnt == 0);
if (fli->fli_mount != NULL)
- fstrans_mount_dtor(fli->fli_mount);
+ fstrans_mount_dtor(fli->fli_mountinfo);
fli_next = fli->fli_succ;
fli->fli_mount = NULL;
+ fli->fli_alias = NULL;
+ fli->fli_mountinfo = NULL;
membar_sync();
fli->fli_self = NULL;
}
@@ -165,13 +220,11 @@
* Dereference mount state.
*/
static void
-fstrans_mount_dtor(struct mount *mp)
+fstrans_mount_dtor(struct fstrans_mount_info *fmi)
{
- struct fstrans_mount_info *fmi;
mutex_enter(&fstrans_mount_lock);
- fmi = mp->mnt_transinfo;
KASSERT(fmi != NULL);
fmi->fmi_ref_cnt -= 1;
if (fmi->fmi_ref_cnt > 0) {
@@ -182,11 +235,12 @@
KASSERT(fmi->fmi_state == FSTRANS_NORMAL);
KASSERT(LIST_FIRST(&fmi->fmi_cow_handler) == NULL);
- mp->mnt_transinfo = NULL;
+ KASSERT(fstrans_gone_count > 0);
+ fstrans_gone_count -= 1;
mutex_exit(&fstrans_mount_lock);
- kmem_free(mp, sizeof(*mp));
+ kmem_free(fmi->fmi_mount, sizeof(*fmi->fmi_mount));
kmem_free(fmi, sizeof(*fmi));
}
@@ -201,11 +255,14 @@
newfmi = kmem_alloc(sizeof(*newfmi), KM_SLEEP);
newfmi->fmi_state = FSTRANS_NORMAL;
newfmi->fmi_ref_cnt = 1;
+ newfmi->fmi_gone = false;
LIST_INIT(&newfmi->fmi_cow_handler);
newfmi->fmi_cow_change = false;
+ newfmi->fmi_mount = mp;
mutex_enter(&fstrans_mount_lock);
mp->mnt_transinfo = newfmi;
+ fstrans_debug_mount(mp);
mutex_exit(&fstrans_mount_lock);
return 0;
@@ -217,10 +274,18 @@
void
fstrans_unmount(struct mount *mp)
{
+ struct fstrans_mount_info *fmi = mp->mnt_transinfo;
- KASSERT(mp->mnt_transinfo != NULL);
+ KASSERT(fmi != NULL);
- fstrans_mount_dtor(mp);
+ mutex_enter(&fstrans_mount_lock);
+ fstrans_debug_unmount(mp);
+ fmi->fmi_gone = true;
+ mp->mnt_transinfo = NULL;
+ fstrans_gone_count += 1;
+ mutex_exit(&fstrans_mount_lock);
+
+ fstrans_mount_dtor(fmi);
}
/*
@@ -229,19 +294,30 @@
static void
fstrans_clear_lwp_info(void)
{
- struct fstrans_lwp_info *fli;
+ struct fstrans_lwp_info *head, **p, *fli;
/*
* Scan our list clearing entries whose mount is gone.
*/
- for (fli = lwp_getspecific(lwp_data_key); fli; fli = fli->fli_succ) {
+ head = lwp_getspecific(lwp_data_key);
+ for (p = &head; *p; p = &(*p)->fli_succ) {
+ fli = *p;
if (fli->fli_mount != NULL &&
- (fli->fli_mount->mnt_iflag & IMNT_GONE) != 0 &&
+ fli->fli_mountinfo->fmi_gone &&
fli->fli_trans_cnt == 0 && fli->fli_cow_cnt == 0) {
- fstrans_mount_dtor(fli->fli_mount);
+ *p = (*p)->fli_succ;
+ fstrans_mount_dtor(fli->fli_mountinfo);
fli->fli_mount = NULL;
+ fli->fli_alias = NULL;
+ fli->fli_mountinfo = NULL;
+ membar_sync();
+ fli->fli_self = NULL;
+
+ if (*p == NULL)
+ break;
}
}
+ lwp_setspecific(lwp_data_key, head);
}
/*
@@ -250,35 +326,32 @@
static struct fstrans_lwp_info *
fstrans_alloc_lwp_info(struct mount *mp)
{
- struct fstrans_lwp_info *fli;
+ struct fstrans_lwp_info *fli, *fli2;
struct fstrans_mount_info *fmi;
+ for (fli = lwp_getspecific(lwp_data_key); fli; fli = fli->fli_succ) {
+ if (fli->fli_mount == mp)
+ return fli;
+ }
+
/*
* Try to reuse a cleared entry or allocate a new one.
*/
- for (fli = lwp_getspecific(lwp_data_key); fli; fli = fli->fli_succ) {
- KASSERT(fli->fli_mount != mp);
- if (fli->fli_mount == NULL) {
+ mutex_enter(&fstrans_lock);
+ LIST_FOREACH(fli, &fstrans_fli_head, fli_list) {
+ membar_sync();
+ if (fli->fli_self == NULL) {
+ KASSERT(fli->fli_mount == NULL);
KASSERT(fli->fli_trans_cnt == 0);
KASSERT(fli->fli_cow_cnt == 0);
+ fli->fli_self = curlwp;
+ fli->fli_succ = lwp_getspecific(lwp_data_key);
+ lwp_setspecific(lwp_data_key, fli);
break;
}
}
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