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Neither tmpfs_nocacheread() nor tmpfs_mappedwrite() needs to call

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vm_object_pip_{add,subtract}() on the swap object because the swap
object can't be destroyed while the vnode is exclusively locked.
Moreover, even if the swap object could have been destroyed during
tmpfs_nocacheread() and tmpfs_mappedwrite() this code is broken
because vm_object_pip_subtract() does not wake up the sleeping thread
that is trying to destroy the swap object.

Free invalid pages after an I/O error.  There is no virtue in keeping
them around in the swap object creating more work for the page daemon.
(I believe that any non-busy page in the swap object will now always
be valid.)

vm_pager_get_pages() does not return a standard errno, so its return
value should not be returned by tmpfs without translation to an errno
value.

There is no reason for the wakeup on vpg in tmpfs_mappedwrite() to
occur with the swap object locked.

Eliminate printf()s from tmpfs_nocacheread() and tmpfs_mappedwrite().
(The swap pager already spam your console if data corruption is
imminent.)

Reviewed by:	kib
MFC after:	3 weeks
This commit is contained in:
Alan Cox 2012-01-14 23:04:27 +00:00
parent 5646ad6d27
commit 93431cb74c
2 changed files with 22 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
sys/fs/tmpfs/tmpfs_subr.c
View File

@ -929,6 +929,7 @@ tmpfs_reg_resize(struct vnode *vp, off_t newsize)
vm_page_sleep(m, "tmfssz");
goto retry;
}
MPASS(m->valid == VM_PAGE_BITS_ALL);
} else if (vm_pager_has_page(uobj, idx, NULL, NULL)) {
m = vm_page_alloc(uobj, idx, VM_ALLOC_NORMAL);
if (m == NULL) {
@ -957,7 +958,6 @@ tmpfs_reg_resize(struct vnode *vp, off_t newsize)
}
if (m != NULL) {
pmap_zero_page_area(m, base, PAGE_SIZE - base);
MPASS(m->valid == VM_PAGE_BITS_ALL);
vm_page_dirty(m);
vm_pager_page_unswapped(m);
}

42
sys/fs/tmpfs/tmpfs_vnops.c
View File

@ -437,18 +437,20 @@ 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;
int error, rv;
VM_OBJECT_LOCK(tobj);
vm_object_pip_add(tobj, 1);
m = vm_page_grab(tobj, idx, VM_ALLOC_WIRED |
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;
rv = vm_pager_get_pages(tobj, &m, 1, 0);
if (rv != VM_PAGER_OK) {
vm_page_lock(m);
vm_page_free(m);
vm_page_unlock(m);
VM_OBJECT_UNLOCK(tobj);
return (EIO);
}
} else
vm_page_zero_invalid(m, TRUE);
@ -456,12 +458,10 @@ tmpfs_nocacheread(vm_object_t tobj, vm_pindex_t idx,
VM_OBJECT_UNLOCK(tobj);
error = uiomove_fromphys(&m, offset, tlen, uio);
VM_OBJECT_LOCK(tobj);
out:
vm_page_lock(m);
vm_page_unwire(m, TRUE);
vm_page_unlock(m);
vm_page_wakeup(m);
vm_object_pip_subtract(tobj, 1);
VM_OBJECT_UNLOCK(tobj);
return (error);
@ -624,7 +624,7 @@ tmpfs_mappedwrite(vm_object_t vobj, vm_object_t tobj, size_t len, struct uio *ui
vm_offset_t offset;
off_t addr;
size_t tlen;
int error;
int error, rv;
error = 0;
@ -664,14 +664,16 @@ tmpfs_mappedwrite(vm_object_t vobj, vm_object_t tobj, size_t len, struct uio *ui
}
nocache:
VM_OBJECT_LOCK(tobj);
vm_object_pip_add(tobj, 1);
tpg = vm_page_grab(tobj, idx, VM_ALLOC_WIRED |
VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
if (tpg->valid != VM_PAGE_BITS_ALL) {
if (vm_pager_has_page(tobj, idx, NULL, NULL)) {
error = vm_pager_get_pages(tobj, &tpg, 1, 0);
if (error != 0) {
printf("tmpfs get pages from pager error [write]\n");
rv = vm_pager_get_pages(tobj, &tpg, 1, 0);
if (rv != VM_PAGER_OK) {
vm_page_lock(tpg);
vm_page_free(tpg);
vm_page_unlock(tpg);
error = EIO;
goto out;
}
} else
@ -685,9 +687,6 @@ tmpfs_mappedwrite(vm_object_t vobj, vm_object_t tobj, size_t len, struct uio *ui
pmap_copy_page(vpg, tpg);
}
VM_OBJECT_LOCK(tobj);
out:
if (vobj != NULL)
VM_OBJECT_LOCK(vobj);
if (error == 0) {
KASSERT(tpg->valid == VM_PAGE_BITS_ALL,
("parts of tpg invalid"));
@ -697,12 +696,13 @@ tmpfs_mappedwrite(vm_object_t vobj, vm_object_t tobj, size_t len, struct uio *ui
vm_page_unwire(tpg, TRUE);
vm_page_unlock(tpg);
vm_page_wakeup(tpg);
if (vpg != NULL)
vm_page_wakeup(vpg);
if (vobj != NULL)
VM_OBJECT_UNLOCK(vobj);
vm_object_pip_subtract(tobj, 1);
out:
VM_OBJECT_UNLOCK(tobj);
if (vpg != NULL) {
VM_OBJECT_LOCK(vobj);
vm_page_wakeup(vpg);
VM_OBJECT_UNLOCK(vobj);
}
return (error);
}