/* given an extent in an lov and a stripe, calculate the extent of the stripe
* that is contained within the lov extent. this returns true if the given
* stripe does intersect with the lov extent. */
int lov_stripe_intersects(struct lov_stripe_md *lsm, int stripeno,
obd_off start, obd_off end,
obd_off *obd_start, obd_off *obd_end)
{
int start_side, end_side;
start_side = lov_stripe_offset(lsm, start, stripeno, obd_start);
end_side = lov_stripe_offset(lsm, end, stripeno, obd_end);
CDEBUG(D_INODE, "["LPU64"->"LPU64"] -> [(%d) "LPU64"->"LPU64" (%d)]\n",
start, end, start_side, *obd_start, *obd_end, end_side);
/* this stripe doesn't intersect the file extent when neither
* start or the end intersected the stripe and obd_start and
* obd_end got rounded up to the save value. */
if (start_side != 0 && end_side != 0 && *obd_start == *obd_end)
return 0;
/* as mentioned in the lov_stripe_offset commentary, end
* might have been shifted in the wrong direction. This
* happens when an end offset is before the stripe when viewed
* through the "mod stripe size" math. we detect it being shifted
* in the wrong direction and touch it up.
* interestingly, this can't underflow since end must be > start
* if we passed through the previous check.
* (should we assert for that somewhere?) */
if (end_side != 0)
(*obd_end)--;
return 1;
}
int lov_page_init_raid0(const struct lu_env *env, struct cl_object *obj,
struct cl_page *page, struct page *vmpage)
{
struct lov_object *loo = cl2lov(obj);
struct lov_layout_raid0 *r0 = lov_r0(loo);
struct lov_io *lio = lov_env_io(env);
struct cl_page *subpage;
struct cl_object *subobj;
struct lov_io_sub *sub;
struct lov_page *lpg = cl_object_page_slice(obj, page);
loff_t offset;
u64 suboff;
int stripe;
int rc;
offset = cl_offset(obj, page->cp_index);
stripe = lov_stripe_number(loo->lo_lsm, offset);
LASSERT(stripe < r0->lo_nr);
rc = lov_stripe_offset(loo->lo_lsm, offset, stripe,
&suboff);
LASSERT(rc == 0);
lpg->lps_invalid = 1;
cl_page_slice_add(page, &lpg->lps_cl, obj, &lov_page_ops);
sub = lov_sub_get(env, lio, stripe);
if (IS_ERR(sub)) {
rc = PTR_ERR(sub);
goto out;
}
subobj = lovsub2cl(r0->lo_sub[stripe]);
subpage = cl_page_find_sub(sub->sub_env, subobj,
cl_index(subobj, suboff), vmpage, page);
lov_sub_put(sub);
if (IS_ERR(subpage)) {
rc = PTR_ERR(subpage);
goto out;
}
if (likely(subpage->cp_parent == page)) {
lu_ref_add(&subpage->cp_reference, "lov", page);
lpg->lps_invalid = 0;
rc = 0;
} else {
CL_PAGE_DEBUG(D_ERROR, env, page, "parent page\n");
CL_PAGE_DEBUG(D_ERROR, env, subpage, "child page\n");
LASSERT(0);
}
out:
return rc;
}