git: cdb62ab74ee0 - main - vfs: add NDFREE_NOTHING and convert several NDFREE_PNBUF callers
Mateusz Guzik
mjg at FreeBSD.org
Tue Jan 12 13:44:10 UTC 2021
The branch main has been updated by mjg:
URL: https://cgit.FreeBSD.org/src/commit/?id=cdb62ab74ee0cb99988c7831d950a6021aaa4879
commit cdb62ab74ee0cb99988c7831d950a6021aaa4879
Author: Mateusz Guzik <mjg at FreeBSD.org>
AuthorDate: 2021-01-12 11:36:30 +0000
Commit: Mateusz Guzik <mjg at FreeBSD.org>
CommitDate: 2021-01-12 13:16:10 +0000
vfs: add NDFREE_NOTHING and convert several NDFREE_PNBUF callers
Check the comment above the routine for reasoning.
---
sys/kern/uipc_usrreq.c | 2 +-
sys/kern/vfs_lookup.c | 27 +++++++++++++++++++++++++++
sys/kern/vfs_syscalls.c | 34 +++++++++++++++++-----------------
sys/sys/namei.h | 2 ++
4 files changed, 47 insertions(+), 18 deletions(-)
diff --git a/sys/kern/uipc_usrreq.c b/sys/kern/uipc_usrreq.c
index ad369fc7b23e..44e48bc864a3 100644
--- a/sys/kern/uipc_usrreq.c
+++ b/sys/kern/uipc_usrreq.c
@@ -1568,7 +1568,7 @@ unp_connectat(int fd, struct socket *so, struct sockaddr *nam,
else
vp = nd.ni_vp;
ASSERT_VOP_LOCKED(vp, "unp_connect");
- NDFREE(&nd, NDF_ONLY_PNBUF);
+ NDFREE_NOTHING(&nd);
if (error)
goto bad;
diff --git a/sys/kern/vfs_lookup.c b/sys/kern/vfs_lookup.c
index da04dd09af40..3b8ee558e023 100644
--- a/sys/kern/vfs_lookup.c
+++ b/sys/kern/vfs_lookup.c
@@ -1487,6 +1487,33 @@ NDFREE_PNBUF(struct nameidata *ndp)
}
}
+/*
+ * NDFREE_PNBUF replacement for callers that know there is no buffer.
+ *
+ * This is a hack. Preferably the VFS layer would not produce anything more
+ * than it was asked to do. Unfortunately several non-LOOKUP cases can add the
+ * HASBUF flag to the result. Even then an interface could be implemented where
+ * the caller specifies what they expected to see in the result and what they
+ * are going to take care of.
+ *
+ * In the meantime provide this kludge as a trivial replacement for NDFREE_PNBUF
+ * calls scattered throughout the kernel where we know for a fact the flag must not
+ * be seen.
+ */
+#ifdef INVARIANTS
+void
+NDFREE_NOTHING(struct nameidata *ndp)
+{
+ struct componentname *cnp;
+
+ cnp = &ndp->ni_cnd;
+ KASSERT(cnp->cn_nameiop == LOOKUP, ("%s: got non-LOOKUP op %d\n",
+ __func__, cnp->cn_nameiop));
+ KASSERT((cnp->cn_flags & (SAVENAME | HASBUF)) == 0,
+ ("%s: bad flags \%" PRIx64 "\n", __func__, cnp->cn_flags));
+}
+#endif
+
void
(NDFREE)(struct nameidata *ndp, const u_int flags)
{
diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
index ce5da109f168..560a003765d5 100644
--- a/sys/kern/vfs_syscalls.c
+++ b/sys/kern/vfs_syscalls.c
@@ -340,7 +340,7 @@ kern_statfs(struct thread *td, const char *path, enum uio_seg pathseg,
return (error);
mp = nd.ni_vp->v_mount;
vfs_ref(mp);
- NDFREE(&nd, NDF_ONLY_PNBUF);
+ NDFREE_NOTHING(&nd);
vput(nd.ni_vp);
return (kern_do_statfs(td, mp, buf));
}
@@ -949,11 +949,11 @@ kern_chdir(struct thread *td, const char *path, enum uio_seg pathseg)
return (error);
if ((error = change_dir(nd.ni_vp, td)) != 0) {
vput(nd.ni_vp);
- NDFREE(&nd, NDF_ONLY_PNBUF);
+ NDFREE_NOTHING(&nd);
return (error);
}
VOP_UNLOCK(nd.ni_vp);
- NDFREE(&nd, NDF_ONLY_PNBUF);
+ NDFREE_NOTHING(&nd);
pwd_chdir(td, nd.ni_vp);
return (0);
}
@@ -991,12 +991,12 @@ sys_chroot(struct thread *td, struct chroot_args *uap)
VOP_UNLOCK(nd.ni_vp);
error = pwd_chroot(td, nd.ni_vp);
vrele(nd.ni_vp);
- NDFREE(&nd, NDF_ONLY_PNBUF);
+ NDFREE_NOTHING(&nd);
return (error);
e_vunlock:
vput(nd.ni_vp);
error:
- NDFREE(&nd, NDF_ONLY_PNBUF);
+ NDFREE_NOTHING(&nd);
return (error);
}
@@ -2118,7 +2118,7 @@ kern_accessat(struct thread *td, int fd, const char *path,
vp = nd.ni_vp;
error = vn_access(vp, amode, usecred, td);
- NDFREE(&nd, NDF_ONLY_PNBUF);
+ NDFREE_NOTHING(&nd);
vput(vp);
out:
if (usecred != cred) {
@@ -2417,7 +2417,7 @@ kern_statat(struct thread *td, int flag, int fd, const char *path,
if (__predict_false(hook != NULL))
hook(nd.ni_vp, sbp);
}
- NDFREE(&nd, NDF_ONLY_PNBUF);
+ NDFREE_NOTHING(&nd);
vput(nd.ni_vp);
#ifdef __STAT_TIME_T_EXT
sbp->st_atim_ext = 0;
@@ -2557,7 +2557,7 @@ kern_pathconf(struct thread *td, const char *path, enum uio_seg pathseg,
pathseg, path, td);
if ((error = namei(&nd)) != 0)
return (error);
- NDFREE(&nd, NDF_ONLY_PNBUF);
+ NDFREE_NOTHING(&nd);
error = VOP_PATHCONF(nd.ni_vp, name, valuep);
vput(nd.ni_vp);
@@ -2613,7 +2613,7 @@ kern_readlinkat(struct thread *td, int fd, const char *path,
if ((error = namei(&nd)) != 0)
return (error);
- NDFREE(&nd, NDF_ONLY_PNBUF);
+ NDFREE_NOTHING(&nd);
vp = nd.ni_vp;
error = kern_readlink_vp(vp, buf, bufseg, count, td);
@@ -2764,7 +2764,7 @@ kern_chflagsat(struct thread *td, int fd, const char *path,
&cap_fchflags_rights, td);
if ((error = namei(&nd)) != 0)
return (error);
- NDFREE(&nd, NDF_ONLY_PNBUF);
+ NDFREE_NOTHING(&nd);
error = setfflags(td, nd.ni_vp, flags);
vrele(nd.ni_vp);
return (error);
@@ -2893,7 +2893,7 @@ kern_fchmodat(struct thread *td, int fd, const char *path,
&cap_fchmod_rights, td);
if ((error = namei(&nd)) != 0)
return (error);
- NDFREE(&nd, NDF_ONLY_PNBUF);
+ NDFREE_NOTHING(&nd);
error = setfmode(td, td->td_ucred, nd.ni_vp, mode);
vrele(nd.ni_vp);
return (error);
@@ -3006,7 +3006,7 @@ kern_fchownat(struct thread *td, int fd, const char *path,
if ((error = namei(&nd)) != 0)
return (error);
- NDFREE(&nd, NDF_ONLY_PNBUF);
+ NDFREE_NOTHING(&nd);
error = setfown(td, td->td_ucred, nd.ni_vp, uid, gid);
vrele(nd.ni_vp);
return (error);
@@ -3219,7 +3219,7 @@ kern_utimesat(struct thread *td, int fd, const char *path,
if ((error = namei(&nd)) != 0)
return (error);
- NDFREE(&nd, NDF_ONLY_PNBUF);
+ NDFREE_NOTHING(&nd);
error = setutimes(td, nd.ni_vp, ts, 2, tptr == NULL);
vrele(nd.ni_vp);
return (error);
@@ -3255,7 +3255,7 @@ kern_lutimes(struct thread *td, const char *path, enum uio_seg pathseg,
NDINIT(&nd, LOOKUP, NOFOLLOW | AUDITVNODE1, pathseg, path, td);
if ((error = namei(&nd)) != 0)
return (error);
- NDFREE(&nd, NDF_ONLY_PNBUF);
+ NDFREE_NOTHING(&nd);
error = setutimes(td, nd.ni_vp, ts, 2, tptr == NULL);
vrele(nd.ni_vp);
return (error);
@@ -3370,7 +3370,7 @@ kern_utimensat(struct thread *td, int fd, const char *path,
* "If both tv_nsec fields are UTIME_OMIT... EACCESS may be detected."
* "Search permission is denied by a component of the path prefix."
*/
- NDFREE(&nd, NDF_ONLY_PNBUF);
+ NDFREE_NOTHING(&nd);
if ((flags & UTIMENS_EXIT) == 0)
error = setutimes(td, nd.ni_vp, ts, 2, flags & UTIMENS_NULL);
vrele(nd.ni_vp);
@@ -4226,7 +4226,7 @@ sys_revoke(struct thread *td, struct revoke_args *uap)
if ((error = namei(&nd)) != 0)
return (error);
vp = nd.ni_vp;
- NDFREE(&nd, NDF_ONLY_PNBUF);
+ NDFREE_NOTHING(&nd);
if (vp->v_type != VCHR || vp->v_rdev == NULL) {
error = EINVAL;
goto out;
@@ -4361,7 +4361,7 @@ kern_getfhat(struct thread *td, int flags, int fd, const char *path,
error = namei(&nd);
if (error != 0)
return (error);
- NDFREE(&nd, NDF_ONLY_PNBUF);
+ NDFREE_NOTHING(&nd);
vp = nd.ni_vp;
bzero(&fh, sizeof(fh));
fh.fh_fsid = vp->v_mount->mnt_stat.f_fsid;
diff --git a/sys/sys/namei.h b/sys/sys/namei.h
index ddba9cbd8912..c045bc7c6bc5 100644
--- a/sys/sys/namei.h
+++ b/sys/sys/namei.h
@@ -288,8 +288,10 @@ void NDFREE(struct nameidata *, const u_int);
} while (0)
#ifdef INVARIANTS
+void NDFREE_NOTHING(struct nameidata *);
void NDVALIDATE(struct nameidata *);
#else
+#define NDFREE_NOTHING(ndp) do { } while (0)
#define NDVALIDATE(ndp) do { } while (0)
#endif
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