svn commit: r346067 - in projects/fuse2: sys/fs/fuse tests/sys/fs/fusefs
Alan Somers
asomers at FreeBSD.org
Tue Apr 9 21:22:04 UTC 2019
Author: asomers
Date: Tue Apr 9 21:22:02 2019
New Revision: 346067
URL: https://svnweb.freebsd.org/changeset/base/346067
Log:
fusefs: cache negative lookups
The FUSE protocol includes a way for a server to tell the client that a
negative lookup response is cacheable for a certain amount of time.
PR: 236226
Sponsored by: The FreeBSD Foundation
Modified:
projects/fuse2/sys/fs/fuse/fuse_internal.c
projects/fuse2/sys/fs/fuse/fuse_internal.h
projects/fuse2/sys/fs/fuse/fuse_node.c
projects/fuse2/sys/fs/fuse/fuse_vnops.c
projects/fuse2/tests/sys/fs/fusefs/lookup.cc
Modified: projects/fuse2/sys/fs/fuse/fuse_internal.c
==============================================================================
--- projects/fuse2/sys/fs/fuse/fuse_internal.c Tue Apr 9 21:18:02 2019 (r346066)
+++ projects/fuse2/sys/fs/fuse/fuse_internal.c Tue Apr 9 21:22:02 2019 (r346067)
@@ -189,22 +189,12 @@ fuse_internal_cache_attrs(struct vnode *vp, struct fus
struct mount *mp;
struct fuse_vnode_data *fvdat;
struct vattr *vp_cache_at;
- struct timespec now, duration, timeout;
mp = vnode_mount(vp);
fvdat = VTOFUD(vp);
- getnanouptime(&now);
- /* "+ 2" is the bound of attr_valid_nsec + now.tv_nsec */
- /* Why oh why isn't there a TIME_MAX defined? */
- if (attr_valid >= INT_MAX || attr_valid + now.tv_sec + 2 >= INT_MAX) {
- fvdat->attr_cache_timeout.sec = INT_MAX;
- } else {
- duration.tv_sec = attr_valid;
- duration.tv_nsec = attr_valid_nsec;
- timespecadd(&duration, &now, &timeout);
- timespec2bintime(&timeout, &fvdat->attr_cache_timeout);
- }
+ fuse_validity_2_bintime(attr_valid, attr_valid_nsec,
+ &fvdat->attr_cache_timeout);
vp_cache_at = VTOVA(vp);
Modified: projects/fuse2/sys/fs/fuse/fuse_internal.h
==============================================================================
--- projects/fuse2/sys/fs/fuse/fuse_internal.h Tue Apr 9 21:18:02 2019 (r346066)
+++ projects/fuse2/sys/fs/fuse/fuse_internal.h Tue Apr 9 21:22:02 2019 (r346067)
@@ -150,6 +150,52 @@ fuse_iosize(struct vnode *vp)
return (vp->v_mount->mnt_stat.f_iosize);
}
+/*
+ * Make a cacheable timeout in bintime format value based on a fuse_attr_out
+ * response
+ */
+static inline void
+fuse_validity_2_bintime(uint64_t attr_valid, uint32_t attr_valid_nsec,
+ struct bintime *timeout)
+{
+ struct timespec now, duration, timeout_ts;
+
+ getnanouptime(&now);
+ /* "+ 2" is the bound of attr_valid_nsec + now.tv_nsec */
+ /* Why oh why isn't there a TIME_MAX defined? */
+ if (attr_valid >= INT_MAX || attr_valid + now.tv_sec + 2 >= INT_MAX) {
+ timeout->sec = INT_MAX;
+ } else {
+ duration.tv_sec = attr_valid;
+ duration.tv_nsec = attr_valid_nsec;
+ timespecadd(&duration, &now, &timeout_ts);
+ timespec2bintime(&timeout_ts, timeout);
+ }
+}
+
+/*
+ * Make a cacheable timeout value in timespec format based on the fuse_entry_out
+ * response
+ */
+static inline void
+fuse_validity_2_timespec(const struct fuse_entry_out *feo,
+ struct timespec *timeout)
+{
+ struct timespec duration, now;
+
+ getnanouptime(&now);
+ /* "+ 2" is the bound of entry_valid_nsec + now.tv_nsec */
+ if (feo->entry_valid >= INT_MAX ||
+ feo->entry_valid + now.tv_sec + 2 >= INT_MAX) {
+ timeout->tv_sec = INT_MAX;
+ } else {
+ duration.tv_sec = feo->entry_valid;
+ duration.tv_nsec = feo->entry_valid_nsec;
+ timespecadd(&duration, &now, timeout);
+ }
+}
+
+
/* access */
#define FVP_ACCESS_NOOP 0x01
Modified: projects/fuse2/sys/fs/fuse/fuse_node.c
==============================================================================
--- projects/fuse2/sys/fs/fuse/fuse_node.c Tue Apr 9 21:18:02 2019 (r346066)
+++ projects/fuse2/sys/fs/fuse/fuse_node.c Tue Apr 9 21:22:02 2019 (r346067)
@@ -291,20 +291,12 @@ fuse_vnode_get(struct mount *mp,
if (dvp != NULL && cnp != NULL && (cnp->cn_flags & MAKEENTRY) != 0 &&
feo != NULL &&
(feo->entry_valid != 0 || feo->entry_valid_nsec != 0)) {
- struct timespec duration, now, timeout;
+ struct timespec timeout;
ASSERT_VOP_LOCKED(*vpp, "fuse_vnode_get");
ASSERT_VOP_LOCKED(dvp, "fuse_vnode_get");
- getnanouptime(&now);
- if (feo->entry_valid >= INT_MAX ||
- feo->entry_valid + now.tv_sec + 2 >= INT_MAX) {
- timeout.tv_sec = INT_MAX;
- } else {
- duration.tv_sec = feo->entry_valid;
- duration.tv_nsec = feo->entry_valid_nsec;
- timespecadd(&duration, &now, &timeout);
- }
+ fuse_validity_2_timespec(feo, &timeout);
cache_enter_time(dvp, *vpp, cnp, &timeout, NULL);
}
Modified: projects/fuse2/sys/fs/fuse/fuse_vnops.c
==============================================================================
--- projects/fuse2/sys/fs/fuse/fuse_vnops.c Tue Apr 9 21:18:02 2019 (r346066)
+++ projects/fuse2/sys/fs/fuse/fuse_vnops.c Tue Apr 9 21:22:02 2019 (r346067)
@@ -706,6 +706,9 @@ fuse_vnop_lookup(struct vop_lookup_args *ap)
struct fuse_dispatcher fdi;
enum fuse_opcode op;
+ struct fuse_entry_out *feo = NULL;
+ struct fuse_attr_out *fao = NULL;
+ struct fuse_attr *fattr = NULL;
uint64_t nid;
struct fuse_access_param facp;
@@ -802,15 +805,18 @@ calldaemon:
if ((op == FUSE_LOOKUP) && !lookup_err) {
/* lookup call succeeded */
nid = ((struct fuse_entry_out *)fdi.answ)->nodeid;
- if (!nid) {
- /*
- * zero nodeid is the same as "not found",
- * but it's also cacheable (which we keep
- * keep on doing not as of writing this)
- * See PR 236226
- */
+ if (nid == 0) {
+ /* zero nodeid means ENOENT and cache it */
+ struct timespec timeout;
+
fdi.answ_stat = ENOENT;
lookup_err = ENOENT;
+ if (cnp->cn_flags & MAKEENTRY) {
+ feo = (struct fuse_entry_out *)fdi.answ;
+ fuse_validity_2_timespec(feo, &timeout);
+ cache_enter_time(dvp, *vpp, cnp, &timeout,
+ NULL);
+ }
} else if (nid == FUSE_ROOT_ID) {
lookup_err = EINVAL;
}
@@ -849,24 +855,7 @@ calldaemon:
err = EJUSTRETURN;
goto out;
}
- /* Consider inserting name into cache. */
- /*
- * No we can't use negative caching, as the fs
- * changes are out of our control.
- * False positives' falseness turns out just as things
- * go by, but false negatives' falseness doesn't.
- * (and aiding the caching mechanism with extra control
- * mechanisms comes quite close to beating the whole purpose
- * caching...)
- */
-#if 0
- if ((cnp->cn_flags & MAKEENTRY) != 0) {
- SDT_PROBE2(fuse, , vnops, trace, 1,
- "inserting NULL into cache");
- cache_enter(dvp, NULL, cnp);
- }
-#endif
err = ENOENT;
goto out;
@@ -874,9 +863,6 @@ calldaemon:
/* !lookup_err */
- struct fuse_entry_out *feo = NULL;
- struct fuse_attr *fattr = NULL;
-
if (op == FUSE_GETATTR) {
fattr = &((struct fuse_attr_out *)fdi.answ)->attr;
} else {
@@ -1040,47 +1026,16 @@ calldaemon:
}
if (op == FUSE_GETATTR) {
- struct fuse_attr_out *fao =
- (struct fuse_attr_out*)fdi.answ;
+ fao = (struct fuse_attr_out*)fdi.answ;
fuse_internal_cache_attrs(*vpp,
&fao->attr, fao->attr_valid,
fao->attr_valid_nsec, NULL);
} else {
- struct fuse_entry_out *feo =
- (struct fuse_entry_out*)fdi.answ;
+ feo = (struct fuse_entry_out*)fdi.answ;
fuse_internal_cache_attrs(*vpp,
&feo->attr, feo->attr_valid,
feo->attr_valid_nsec, NULL);
}
-
- /* Insert name into cache if appropriate. */
-
- /*
- * Nooo, caching is evil. With caching, we can't avoid stale
- * information taking over the playground (cached info is not
- * just positive/negative, it does have qualitative aspects,
- * too). And a (VOP/FUSE)_GETATTR is always thrown anyway, when
- * walking down along cached path components, and that's not
- * any cheaper than FUSE_LOOKUP. This might change with
- * implementing kernel side attr caching, but... In Linux,
- * lookup results are not cached, and the daemon is bombarded
- * with FUSE_LOOKUPS on and on. This shows that by design, the
- * daemon is expected to handle frequent lookup queries
- * efficiently, do its caching in userspace, and so on.
- *
- * So just leave the name cache alone.
- */
-
- /*
- * Well, now I know, Linux caches lookups, but with a
- * timeout... So it's the same thing as attribute caching:
- * we can deal with it when implement timeouts.
- */
-#if 0
- if (cnp->cn_flags & MAKEENTRY) {
- cache_enter(dvp, *vpp, cnp);
- }
-#endif
}
out:
if (!lookup_err) {
Modified: projects/fuse2/tests/sys/fs/fusefs/lookup.cc
==============================================================================
--- projects/fuse2/tests/sys/fs/fusefs/lookup.cc Tue Apr 9 21:18:02 2019 (r346066)
+++ projects/fuse2/tests/sys/fs/fusefs/lookup.cc Tue Apr 9 21:22:02 2019 (r346067)
@@ -169,8 +169,7 @@ TEST_F(Lookup, entry_cache)
* If the daemon returns an error of 0 and an inode of 0, that's a flag for
* "ENOENT and cache it" with the given entry_timeout
*/
-/* https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=236226 */
-TEST_F(Lookup, DISABLED_entry_cache_negative)
+TEST_F(Lookup, entry_cache_negative)
{
struct timespec entry_valid = {.tv_sec = TIME_T_MAX, .tv_nsec = 0};
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