svn commit: r351193 - head/sys/kern
Mateusz Guzik
mjg at FreeBSD.org
Sun Aug 18 18:40:13 UTC 2019
Author: mjg
Date: Sun Aug 18 18:40:12 2019
New Revision: 351193
URL: https://svnweb.freebsd.org/changeset/base/351193
Log:
vfs: stop always overwriting ->mnt_stat in VFS_STATFS
The struct is already populated on each mount (and remount). Fields are either
constant or not used by filesystem in the first place.
Some infrequently used functions use it to avoid having to allocate a new buffer
and are left alone.
The current code results in an avoidable copying single-threaded and significant
cache line bouncing multithreaded
While here deduplicate initial filling of the struct.
Reviewed by: kib
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D21317
Modified:
head/sys/kern/vfs_mount.c
head/sys/kern/vfs_syscalls.c
Modified: head/sys/kern/vfs_mount.c
==============================================================================
--- head/sys/kern/vfs_mount.c Sun Aug 18 17:12:06 2019 (r351192)
+++ head/sys/kern/vfs_mount.c Sun Aug 18 18:40:12 2019 (r351193)
@@ -1831,12 +1831,15 @@ vfs_copyopt(struct vfsoptlist *opts, const char *name,
int
__vfs_statfs(struct mount *mp, struct statfs *sbp)
{
- int error;
- error = mp->mnt_op->vfs_statfs(mp, &mp->mnt_stat);
- if (sbp != &mp->mnt_stat)
- *sbp = mp->mnt_stat;
- return (error);
+ /*
+ * Set these in case the underlying filesystem fails to do so.
+ */
+ sbp->f_version = STATFS_VERSION;
+ sbp->f_namemax = NAME_MAX;
+ sbp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
+
+ return (mp->mnt_op->vfs_statfs(mp, sbp));
}
void
Modified: head/sys/kern/vfs_syscalls.c
==============================================================================
--- head/sys/kern/vfs_syscalls.c Sun Aug 18 17:12:06 2019 (r351192)
+++ head/sys/kern/vfs_syscalls.c Sun Aug 18 18:40:12 2019 (r351193)
@@ -248,7 +248,6 @@ statfs_scale_blocks(struct statfs *sf, long max_size)
static int
kern_do_statfs(struct thread *td, struct mount *mp, struct statfs *buf)
{
- struct statfs *sp;
int error;
if (mp == NULL)
@@ -262,17 +261,9 @@ kern_do_statfs(struct thread *td, struct mount *mp, st
if (error != 0)
goto out;
#endif
- /*
- * Set these in case the underlying filesystem fails to do so.
- */
- sp = &mp->mnt_stat;
- sp->f_version = STATFS_VERSION;
- sp->f_namemax = NAME_MAX;
- sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
- error = VFS_STATFS(mp, sp);
+ error = VFS_STATFS(mp, buf);
if (error != 0)
goto out;
- *buf = *sp;
if (priv_check(td, PRIV_VFS_GENERATION)) {
buf->f_fsid.val[0] = buf->f_fsid.val[1] = 0;
prison_enforce_statfs(td->td_ucred, mp, buf);
@@ -476,13 +467,6 @@ restart:
if (sfsp != NULL && count < maxcount) {
sp = &mp->mnt_stat;
/*
- * Set these in case the underlying filesystem
- * fails to do so.
- */
- sp->f_version = STATFS_VERSION;
- sp->f_namemax = NAME_MAX;
- sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
- /*
* If MNT_NOWAIT is specified, do not refresh
* the fsstat cache.
*/
@@ -4545,7 +4529,6 @@ sys_fhstatfs(struct thread *td, struct fhstatfs_args *
int
kern_fhstatfs(struct thread *td, fhandle_t fh, struct statfs *buf)
{
- struct statfs *sp;
struct mount *mp;
struct vnode *vp;
int error;
@@ -4569,16 +4552,7 @@ kern_fhstatfs(struct thread *td, fhandle_t fh, struct
if (error != 0)
goto out;
#endif
- /*
- * Set these in case the underlying filesystem fails to do so.
- */
- sp = &mp->mnt_stat;
- sp->f_version = STATFS_VERSION;
- sp->f_namemax = NAME_MAX;
- sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
- error = VFS_STATFS(mp, sp);
- if (error == 0)
- *buf = *sp;
+ error = VFS_STATFS(mp, buf);
out:
vfs_unbusy(mp);
return (error);
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