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 In particular, lookup results cached in the inode/v_data is no longer valid and needs recalculating.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); } _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
