svn commit: r367632 - head/sys/kern
Konstantin Belousov
kib at FreeBSD.org
Fri Nov 13 09:42:34 UTC 2020
Author: kib
Date: Fri Nov 13 09:42:32 2020
New Revision: 367632
URL: https://svnweb.freebsd.org/changeset/base/367632
Log:
Allow some VOPs to return ERELOOKUP to indicate VFS operation restart at top level.
Restart syscalls and some sync operations when filesystem indicated
ERELOOKUP condition, mostly for VOPs operating on metdata. In
particular, lookup results cached in the inode/v_data is no longer
valid and needs recalculating. Right now this should be nop.
Assert that ERELOOKUP is catched everywhere and not returned to
userspace, by asserting that td_errno != ERELOOKUP on syscall return
path.
In collaboration with: pho
Reviewed by: mckusick (previous version), markj
Tested by: markj (syzkaller), pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D26136
Modified:
head/sys/kern/subr_syscall.c
head/sys/kern/uipc_usrreq.c
head/sys/kern/vfs_subr.c
head/sys/kern/vfs_syscalls.c
Modified: head/sys/kern/subr_syscall.c
==============================================================================
--- head/sys/kern/subr_syscall.c Fri Nov 13 09:31:57 2020 (r367631)
+++ head/sys/kern/subr_syscall.c Fri Nov 13 09:42:32 2020 (r367632)
@@ -217,6 +217,8 @@ syscallret(struct thread *td)
KASSERT((td->td_pflags & TDP_FORKING) == 0,
("fork() did not clear TDP_FORKING upon completion"));
+ KASSERT(td->td_errno != ERELOOKUP,
+ ("ERELOOKUP not consumed syscall %d", td->td_sa.code));
p = td->td_proc;
sa = &td->td_sa;
Modified: head/sys/kern/uipc_usrreq.c
==============================================================================
--- head/sys/kern/uipc_usrreq.c Fri Nov 13 09:31:57 2020 (r367631)
+++ head/sys/kern/uipc_usrreq.c Fri Nov 13 09:42:32 2020 (r367632)
@@ -671,6 +671,8 @@ restart:
vput(nd.ni_dvp);
if (error) {
vn_finished_write(mp);
+ if (error == ERELOOKUP)
+ goto restart;
goto error;
}
vp = nd.ni_vp;
Modified: head/sys/kern/vfs_subr.c
==============================================================================
--- head/sys/kern/vfs_subr.c Fri Nov 13 09:31:57 2020 (r367631)
+++ head/sys/kern/vfs_subr.c Fri Nov 13 09:42:32 2020 (r367632)
@@ -1937,7 +1937,10 @@ bufobj_invalbuf(struct bufobj *bo, int flags, int slpf
}
if (bo->bo_dirty.bv_cnt > 0) {
BO_UNLOCK(bo);
- if ((error = BO_SYNC(bo, MNT_WAIT)) != 0)
+ do {
+ error = BO_SYNC(bo, MNT_WAIT);
+ } while (error == ERELOOKUP);
+ if (error != 0)
return (error);
/*
* XXX We could save a lock/unlock if this was only
@@ -3678,7 +3681,9 @@ loop:
vm_object_page_clean(vp->v_object, 0, 0, 0);
VM_OBJECT_WUNLOCK(vp->v_object);
}
- error = VOP_FSYNC(vp, MNT_WAIT, td);
+ do {
+ error = VOP_FSYNC(vp, MNT_WAIT, td);
+ } while (error == ERELOOKUP);
if (error != 0) {
VOP_UNLOCK(vp);
vdrop(vp);
Modified: head/sys/kern/vfs_syscalls.c
==============================================================================
--- head/sys/kern/vfs_syscalls.c Fri Nov 13 09:31:57 2020 (r367631)
+++ head/sys/kern/vfs_syscalls.c Fri Nov 13 09:42:32 2020 (r367632)
@@ -1384,6 +1384,8 @@ restart:
NDFREE(&nd, NDF_ONLY_PNBUF);
vput(nd.ni_dvp);
vn_finished_write(mp);
+ if (error == ERELOOKUP)
+ goto restart;
return (error);
}
@@ -1470,6 +1472,8 @@ out:
vput(nd.ni_dvp);
vn_finished_write(mp);
NDFREE(&nd, NDF_ONLY_PNBUF);
+ if (error == ERELOOKUP)
+ goto restart;
return (error);
}
@@ -1568,7 +1572,7 @@ kern_linkat(struct thread *td, int fd1, int fd2, const
return (error);
NDFREE(&nd, NDF_ONLY_PNBUF);
error = kern_linkat_vp(td, nd.ni_vp, fd2, path2, segflag);
- } while (error == EAGAIN);
+ } while (error == EAGAIN || error == ERELOOKUP);
return (error);
}
@@ -1741,6 +1745,8 @@ out2:
NDFREE(&nd, NDF_ONLY_PNBUF);
vput(nd.ni_dvp);
vn_finished_write(mp);
+ if (error == ERELOOKUP)
+ goto restart;
out:
if (segflg != UIO_SYSSPACE)
uma_zfree(namei_zone, tmppath);
@@ -1791,6 +1797,8 @@ restart:
NDFREE(&nd, NDF_ONLY_PNBUF);
vput(nd.ni_dvp);
vn_finished_write(mp);
+ if (error == ERELOOKUP)
+ goto restart;
return (error);
}
@@ -1937,6 +1945,8 @@ out:
vrele(vp);
else
vput(vp);
+ if (error == ERELOOKUP)
+ goto restart;
fdout:
if (fp != NULL)
fdrop(fp, td);
@@ -3395,7 +3405,8 @@ kern_truncate(struct thread *td, const char *path, enu
int error;
if (length < 0)
- return(EINVAL);
+ return (EINVAL);
+retry:
NDINIT(&nd, LOOKUP, FOLLOW | AUDITVNODE1, pathseg, path, td);
if ((error = namei(&nd)) != 0)
return (error);
@@ -3424,6 +3435,8 @@ kern_truncate(struct thread *td, const char *path, enu
vn_finished_write(mp);
vn_rangelock_unlock(vp, rl_cookie);
vrele(vp);
+ if (error == ERELOOKUP)
+ goto retry;
return (error);
}
@@ -3479,6 +3492,7 @@ kern_fsync(struct thread *td, int fd, bool fullsync)
if (!fullsync)
/* XXXKIB: compete outstanding aio writes */;
#endif
+retry:
error = vn_start_write(vp, &mp, V_WAIT | PCATCH);
if (error != 0)
goto drop;
@@ -3498,6 +3512,8 @@ kern_fsync(struct thread *td, int fd, bool fullsync)
error = fullsync ? VOP_FSYNC(vp, MNT_WAIT, td) : VOP_FDATASYNC(vp, td);
VOP_UNLOCK(vp);
vn_finished_write(mp);
+ if (error == ERELOOKUP)
+ goto retry;
drop:
fdrop(fp, td);
return (error);
@@ -3679,7 +3695,7 @@ again:
* are links to the same vnode), then there is nothing to do.
*/
if (fvp == tvp)
- error = -1;
+ error = ERESTART;
#ifdef MAC
else
error = mac_vnode_check_rename_to(td->td_ucred, tdvp,
@@ -3708,8 +3724,10 @@ out:
out1:
if (fromnd.ni_startdir)
vrele(fromnd.ni_startdir);
- if (error == -1)
+ if (error == ERESTART)
return (0);
+ if (error == ERELOOKUP)
+ goto again;
return (error);
}
@@ -3803,6 +3821,8 @@ out:
if (error == 0)
vput(nd.ni_vp);
vn_finished_write(mp);
+ if (error == ERELOOKUP)
+ goto restart;
return (error);
}
@@ -3903,6 +3923,8 @@ out:
vrele(nd.ni_dvp);
else
vput(nd.ni_dvp);
+ if (error == ERELOOKUP)
+ goto restart;
fdout:
if (fp != NULL)
fdrop(fp, td);
@@ -4416,7 +4438,8 @@ kern_fhlinkat(struct thread *td, int fd, const char *p
if (error != 0)
return (error);
VOP_UNLOCK(vp);
- } while ((error = kern_linkat_vp(td, vp, fd, path, pathseg)) == EAGAIN);
+ error = kern_linkat_vp(td, vp, fd, path, pathseg);
+ } while (error == EAGAIN || error == ERELOOKUP);
return (error);
}
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