Could someone explain what was the cause and why this fixes the issue? When I read it, it looked like that a vm object could be in 2 locations and one of them looked the cause of the problem. But I couldn't figure out thereafter.
Thanks, Hiro On Wed, 7 Oct 2009 23:17:15 +0000 (UTC) Xin LI <delp...@freebsd.org> wrote: > Author: delphij > Date: Wed Oct 7 23:17:15 2009 > New Revision: 197850 > URL: http://svn.freebsd.org/changeset/base/197850 > > Log: > Add a special workaround to handle UIO_NOCOPY case. This fixes data > corruption observed when sendfile() is being used. > > PR: kern/127213 > Submitted by: gk > MFC after: 2 weeks > > Modified: > head/sys/fs/tmpfs/tmpfs_vnops.c > > Modified: head/sys/fs/tmpfs/tmpfs_vnops.c > ============================================================================== > --- head/sys/fs/tmpfs/tmpfs_vnops.c Wed Oct 7 23:01:31 2009 > (r197849) > +++ head/sys/fs/tmpfs/tmpfs_vnops.c Wed Oct 7 23:17:15 2009 > (r197850) > @@ -43,6 +43,8 @@ __FBSDID("$FreeBSD$"); > #include <sys/priv.h> > #include <sys/proc.h> > #include <sys/resourcevar.h> > +#include <sys/sched.h> > +#include <sys/sf_buf.h> > #include <sys/stat.h> > #include <sys/systm.h> > #include <sys/unistd.h> > @@ -428,15 +430,72 @@ tmpfs_setattr(struct vop_setattr_args *v > } > > /* --------------------------------------------------------------------- */ > +static int > +tmpfs_nocacheread(vm_object_t tobj, vm_pindex_t idx, > + vm_offset_t offset, size_t tlen, struct uio *uio) > +{ > + vm_page_t m; > + int error; > + > + VM_OBJECT_LOCK(tobj); > + vm_object_pip_add(tobj, 1); > + m = vm_page_grab(tobj, idx, VM_ALLOC_WIRED | > + VM_ALLOC_ZERO | VM_ALLOC_NORMAL | VM_ALLOC_RETRY); > + if (m->valid != VM_PAGE_BITS_ALL) { > + if (vm_pager_has_page(tobj, idx, NULL, NULL)) { > + error = vm_pager_get_pages(tobj, &m, 1, 0); > + if (error != 0) { > + printf("tmpfs get pages from pager error > [read]\n"); > + goto out; > + } > + } else > + vm_page_zero_invalid(m, TRUE); > + } > + VM_OBJECT_UNLOCK(tobj); > + error = uiomove_fromphys(&m, offset, tlen, uio); > + VM_OBJECT_LOCK(tobj); > +out: > + vm_page_lock_queues(); > + vm_page_unwire(m, TRUE); > + vm_page_unlock_queues(); > + vm_page_wakeup(m); > + vm_object_pip_subtract(tobj, 1); > + VM_OBJECT_UNLOCK(tobj); > + > + return (error); > +} > + > +static __inline int > +tmpfs_nocacheread_buf(vm_object_t tobj, vm_pindex_t idx, > + vm_offset_t offset, size_t tlen, void *buf) > +{ > + struct uio uio; > + struct iovec iov; > + > + uio.uio_iovcnt = 1; > + uio.uio_iov = &iov; > + iov.iov_base = buf; > + iov.iov_len = tlen; > + > + uio.uio_offset = 0; > + uio.uio_resid = tlen; > + uio.uio_rw = UIO_READ; > + uio.uio_segflg = UIO_SYSSPACE; > + uio.uio_td = curthread; > + > + return (tmpfs_nocacheread(tobj, idx, offset, tlen, &uio)); > +} > > static int > tmpfs_mappedread(vm_object_t vobj, vm_object_t tobj, size_t len, struct uio > *uio) > { > + struct sf_buf *sf; > vm_pindex_t idx; > vm_page_t m; > vm_offset_t offset; > off_t addr; > size_t tlen; > + char *ma; > int error; > > addr = uio->uio_offset; > @@ -461,33 +520,30 @@ lookupvpg: > vm_page_wakeup(m); > VM_OBJECT_UNLOCK(vobj); > return (error); > + } else if (m != NULL && uio->uio_segflg == UIO_NOCOPY) { > + if (vm_page_sleep_if_busy(m, FALSE, "tmfsmr")) > + goto lookupvpg; > + vm_page_busy(m); > + VM_OBJECT_UNLOCK(vobj); > + sched_pin(); > + sf = sf_buf_alloc(m, SFB_CPUPRIVATE); > + ma = (char *)sf_buf_kva(sf); > + error = tmpfs_nocacheread_buf(tobj, idx, offset, tlen, > + ma + offset); > + if (error == 0) { > + uio->uio_offset += tlen; > + uio->uio_resid -= tlen; > + } > + sf_buf_free(sf); > + sched_unpin(); > + VM_OBJECT_LOCK(vobj); > + vm_page_wakeup(m); > + VM_OBJECT_UNLOCK(vobj); > + return (error); > } > VM_OBJECT_UNLOCK(vobj); > nocache: > - VM_OBJECT_LOCK(tobj); > - vm_object_pip_add(tobj, 1); > - m = vm_page_grab(tobj, idx, VM_ALLOC_WIRED | > - VM_ALLOC_ZERO | VM_ALLOC_NORMAL | VM_ALLOC_RETRY); > - if (m->valid != VM_PAGE_BITS_ALL) { > - if (vm_pager_has_page(tobj, idx, NULL, NULL)) { > - error = vm_pager_get_pages(tobj, &m, 1, 0); > - if (error != 0) { > - printf("tmpfs get pages from pager error > [read]\n"); > - goto out; > - } > - } else > - vm_page_zero_invalid(m, TRUE); > - } > - VM_OBJECT_UNLOCK(tobj); > - error = uiomove_fromphys(&m, offset, tlen, uio); > - VM_OBJECT_LOCK(tobj); > -out: > - vm_page_lock_queues(); > - vm_page_unwire(m, TRUE); > - vm_page_unlock_queues(); > - vm_page_wakeup(m); > - vm_object_pip_subtract(tobj, 1); > - VM_OBJECT_UNLOCK(tobj); > + error = tmpfs_nocacheread(tobj, idx, offset, tlen, uio); > > return (error); > } > _______________________________________________ > svn-src-all@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/svn-src-all > To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org" _______________________________________________ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
