/**
* Implements cl_io_operations::cio_prepare_write() method for osc layer.
*
* \retval -EIO transfer initiated against this osc will most likely fail
* \retval 0 transfer initiated against this osc will most likely succeed.
*
* The reason for this check is to immediately return an error to the caller
* in the case of a deactivated import. Note, that import can be deactivated
* later, while pages, dirtied by this IO, are still in the cache, but this is
* irrelevant, because that would still return an error to the application (if
* it does fsync), but many applications don't do fsync because of performance
* issues, and we wanted to return an -EIO at write time to notify the
* application.
*/
static int osc_io_prepare_write(const struct lu_env *env,
const struct cl_io_slice *ios,
const struct cl_page_slice *slice,
unsigned from, unsigned to)
{
struct osc_device *dev = lu2osc_dev(slice->cpl_obj->co_lu.lo_dev);
struct obd_import *imp = class_exp2cliimp(dev->od_exp);
struct osc_io *oio = cl2osc_io(env, ios);
int result = 0;
/*
* This implements OBD_BRW_CHECK logic from old client.
*/
if (imp == NULL || imp->imp_invalid)
result = -EIO;
if (result == 0 && oio->oi_lockless)
/* this page contains `invalid' data, but who cares?
* nobody can access the invalid data.
* in osc_io_commit_write(), we're going to write exact
* [from, to) bytes of this page to OST. -jay */
cl_page_export(env, slice->cpl_page, 1);
return result;
}
static int vvp_io_read_page(const struct lu_env *env,
const struct cl_io_slice *ios,
const struct cl_page_slice *slice)
{
struct cl_io *io = ios->cis_io;
struct cl_object *obj = slice->cpl_obj;
struct ccc_page *cp = cl2ccc_page(slice);
struct cl_page *page = slice->cpl_page;
struct inode *inode = ccc_object_inode(obj);
struct ll_sb_info *sbi = ll_i2sbi(inode);
struct ll_file_data *fd = cl2ccc_io(env, ios)->cui_fd;
struct ll_readahead_state *ras = &fd->fd_ras;
struct page *vmpage = cp->cpg_page;
struct cl_2queue *queue = &io->ci_queue;
int rc;
CLOBINVRNT(env, obj, ccc_object_invariant(obj));
LASSERT(slice->cpl_obj == obj);
ENTRY;
if (sbi->ll_ra_info.ra_max_pages_per_file &&
sbi->ll_ra_info.ra_max_pages)
ras_update(sbi, inode, ras, page->cp_index,
cp->cpg_defer_uptodate);
/* Sanity check whether the page is protected by a lock. */
rc = cl_page_is_under_lock(env, io, page);
if (rc != -EBUSY) {
CL_PAGE_HEADER(D_WARNING, env, page, "%s: %d\n",
rc == -ENODATA ? "without a lock" :
"match failed", rc);
if (rc != -ENODATA)
RETURN(rc);
}
if (cp->cpg_defer_uptodate) {
cp->cpg_ra_used = 1;
cl_page_export(env, page, 1);
}
/*
* Add page into the queue even when it is marked uptodate above.
* this will unlock it automatically as part of cl_page_list_disown().
*/
cl_2queue_add(queue, page);
if (sbi->ll_ra_info.ra_max_pages_per_file &&
sbi->ll_ra_info.ra_max_pages)
ll_readahead(env, io, ras,
vmpage->mapping, &queue->c2_qin, fd->fd_flags);
RETURN(0);
}
int lov_page_init_empty(const struct lu_env *env, struct cl_object *obj,
struct cl_page *page, struct page *vmpage)
{
struct lov_page *lpg = cl_object_page_slice(obj, page);
void *addr;
cl_page_slice_add(page, &lpg->lps_cl, obj, &lov_empty_page_ops);
addr = kmap(vmpage);
memset(addr, 0, cl_page_size(obj));
kunmap(vmpage);
cl_page_export(env, page, 1);
return 0;
}
/**
* Prepare partially written-to page for a write.
*/
static int vvp_io_prepare_partial(const struct lu_env *env, struct cl_io *io,
struct cl_object *obj, struct cl_page *pg,
struct ccc_page *cp,
unsigned from, unsigned to)
{
struct cl_attr *attr = ccc_env_thread_attr(env);
loff_t offset = cl_offset(obj, pg->cp_index);
int result;
cl_object_attr_lock(obj);
result = cl_object_attr_get(env, obj, attr);
cl_object_attr_unlock(obj);
if (result == 0) {
/*
* If are writing to a new page, no need to read old data.
* The extent locking will have updated the KMS, and for our
* purposes here we can treat it like i_size.
*/
if (attr->cat_kms <= offset) {
char *kaddr = ll_kmap_atomic(cp->cpg_page, KM_USER0);
memset(kaddr, 0, cl_page_size(obj));
ll_kunmap_atomic(kaddr, KM_USER0);
} else if (cp->cpg_defer_uptodate)
cp->cpg_ra_used = 1;
else
result = vvp_page_sync_io(env, io, pg, cp, CRT_READ);
/*
* In older implementations, obdo_refresh_inode is called here
* to update the inode because the write might modify the
* object info at OST. However, this has been proven useless,
* since LVB functions will be called when user space program
* tries to retrieve inode attribute. Also, see bug 15909 for
* details. -jay
*/
if (result == 0)
cl_page_export(env, pg, 1);
}
return result;
}
