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Eliminate tn_reg.tn_aobj_pages. Instead, correctly maintain the vm

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object's size field.  Previously, that field was always zero, even
when the object tn_reg.tn_aobj contained numerous pages.

Apply style fixes to tmpfs_reg_resize().

In collaboration with:	kib
This commit is contained in:
Alan Cox 2011-02-13 14:46:39 +00:00
parent be2a6988a1
commit b10d1d5d60
2 changed files with 26 additions and 33 deletions
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1
sys/fs/tmpfs/tmpfs.h
View File

@ -283,7 +283,6 @@ struct tmpfs_node {
* issue the required page ins or page outs whenever
* a position within the file is accessed. */
vm_object_t tn_aobj;
size_t tn_aobj_pages;
}tn_reg;

58
sys/fs/tmpfs/tmpfs_subr.c
View File

@ -146,7 +146,6 @@ tmpfs_alloc_node(struct tmpfs_mount *tmp, enum vtype type,
nnode->tn_reg.tn_aobj =
vm_pager_allocate(OBJT_SWAP, NULL, 0, VM_PROT_DEFAULT, 0,
NULL /* XXXKIB - tmpfs needs swap reservation */);
nnode->tn_reg.tn_aobj_pages = 0;
break;
default:
@ -184,7 +183,7 @@ tmpfs_alloc_node(struct tmpfs_mount *tmp, enum vtype type,
void
tmpfs_free_node(struct tmpfs_mount *tmp, struct tmpfs_node *node)
{
size_t pages = 0;
vm_object_t uobj;
#ifdef INVARIANTS
TMPFS_NODE_LOCK(node);
@ -220,9 +219,13 @@ tmpfs_free_node(struct tmpfs_mount *tmp, struct tmpfs_node *node)
break;
case VREG:
if (node->tn_reg.tn_aobj != NULL)
vm_object_deallocate(node->tn_reg.tn_aobj);
pages = node->tn_reg.tn_aobj_pages;
uobj = node->tn_reg.tn_aobj;
if (uobj != NULL) {
TMPFS_LOCK(tmp);
tmp->tm_pages_used -= uobj->size;
TMPFS_UNLOCK(tmp);
vm_object_deallocate(uobj);
}
break;
default:
@ -231,10 +234,6 @@ tmpfs_free_node(struct tmpfs_mount *tmp, struct tmpfs_node *node)
free_unr(tmp->tm_ino_unr, node->tn_id);
uma_zfree(tmp->tm_node_pool, node);
TMPFS_LOCK(tmp);
tmp->tm_pages_used -= pages;
TMPFS_UNLOCK(tmp);
}
/* --------------------------------------------------------------------- */
@ -884,16 +883,20 @@ tmpfs_dir_whiteout_remove(struct vnode *dvp, struct componentname *cnp)
int
tmpfs_reg_resize(struct vnode *vp, off_t newsize)
{
int error;
size_t newpages, oldpages;
struct tmpfs_mount *tmp;
struct tmpfs_node *node;
vm_object_t uobj;
vm_page_t m;
vm_pindex_t newpages, oldpages;
off_t oldsize;
size_t zerolen;
int error;
MPASS(vp->v_type == VREG);
MPASS(newsize >= 0);
node = VP_TO_TMPFS_NODE(vp);
uobj = node->tn_reg.tn_aobj;
tmp = VFS_TO_TMPFS(vp->v_mount);
/* Convert the old and new sizes to the number of pages needed to
@ -901,9 +904,9 @@ tmpfs_reg_resize(struct vnode *vp, off_t newsize)
* because the last allocated page can accommodate the change on
* its own. */
oldsize = node->tn_size;
oldpages = round_page(oldsize) / PAGE_SIZE;
MPASS(oldpages == node->tn_reg.tn_aobj_pages);
newpages = round_page(newsize) / PAGE_SIZE;
oldpages = OFF_TO_IDX(oldsize + PAGE_MASK);
MPASS(oldpages == uobj->size);
newpages = OFF_TO_IDX(newsize + PAGE_MASK);
if (newpages > oldpages &&
newpages - oldpages > TMPFS_PAGES_AVAIL(tmp)) {
@ -911,48 +914,39 @@ tmpfs_reg_resize(struct vnode *vp, off_t newsize)
goto out;
}
node->tn_reg.tn_aobj_pages = newpages;
TMPFS_LOCK(tmp);
tmp->tm_pages_used += (newpages - oldpages);
TMPFS_UNLOCK(tmp);
node->tn_size = newsize;
vnode_pager_setsize(vp, newsize);
VM_OBJECT_LOCK(uobj);
if (newsize < oldsize) {
size_t zerolen = round_page(newsize) - newsize;
vm_object_t uobj = node->tn_reg.tn_aobj;
vm_page_t m;
/*
* free "backing store"
*/
VM_OBJECT_LOCK(uobj);
if (newpages < oldpages) {
swap_pager_freespace(uobj,
newpages, oldpages - newpages);
vm_object_page_remove(uobj,
OFF_TO_IDX(newsize + PAGE_MASK), 0, FALSE);
swap_pager_freespace(uobj, newpages, oldpages -
newpages);
vm_object_page_remove(uobj, newpages, 0, FALSE);
}
/*
* zero out the truncated part of the last page.
*/
zerolen = round_page(newsize) - newsize;
if (zerolen > 0) {
m = vm_page_grab(uobj, OFF_TO_IDX(newsize),
VM_ALLOC_NOBUSY | VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
pmap_zero_page_area(m, PAGE_SIZE - zerolen,
zerolen);
pmap_zero_page_area(m, PAGE_SIZE - zerolen, zerolen);
}
VM_OBJECT_UNLOCK(uobj);
}
uobj->size = newpages;
VM_OBJECT_UNLOCK(uobj);
error = 0;
out:
return error;
return (error);
}
/* --------------------------------------------------------------------- */