/**
* Lustre implementation of a vm_operations_struct::fault() method, called by
* VM to server page fault (both in kernel and user space).
*
* \param vma - is virtual area struct related to page fault
* \param vmf - structure which describe type and address where hit fault
*
* \return allocated and filled _locked_ page for address
* \retval VM_FAULT_ERROR on general error
* \retval NOPAGE_OOM not have memory for allocate new page
*/
static int ll_fault0(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct lu_env *env;
struct cl_io *io;
struct vvp_io *vio = NULL;
struct page *vmpage;
unsigned long ra_flags;
struct cl_env_nest nest;
int result;
int fault_ret = 0;
io = ll_fault_io_init(vma, &env, &nest, vmf->pgoff, &ra_flags);
if (IS_ERR(io))
return to_fault_error(PTR_ERR(io));
result = io->ci_result;
if (result == 0) {
vio = vvp_env_io(env);
vio->u.fault.ft_vma = vma;
vio->u.fault.ft_vmpage = NULL;
vio->u.fault.ft_vmf = vmf;
vio->u.fault.ft_flags = 0;
vio->u.fault.ft_flags_valid = false;
/* May call ll_readpage() */
ll_cl_add(vma->vm_file, env, io);
result = cl_io_loop(env, io);
ll_cl_remove(vma->vm_file, env);
/* ft_flags are only valid if we reached
* the call to filemap_fault
*/
if (vio->u.fault.ft_flags_valid)
fault_ret = vio->u.fault.ft_flags;
vmpage = vio->u.fault.ft_vmpage;
if (result != 0 && vmpage) {
put_page(vmpage);
vmf->page = NULL;
}
}
cl_io_fini(env, io);
cl_env_nested_put(&nest, env);
vma->vm_flags |= ra_flags;
if (result != 0 && !(fault_ret & VM_FAULT_RETRY))
fault_ret |= to_fault_error(result);
CDEBUG(D_MMAP, "%s fault %d/%d\n",
current->comm, fault_ret, result);
return fault_ret;
}
/**
* Lustre implementation of a vm_operations_struct::fault() method, called by
* VM to server page fault (both in kernel and user space).
*
* \param vma - is virtiual area struct related to page fault
* \param vmf - structure which describe type and address where hit fault
*
* \return allocated and filled _locked_ page for address
* \retval VM_FAULT_ERROR on general error
* \retval NOPAGE_OOM not have memory for allocate new page
*/
static int ll_fault0(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct lu_env *env;
struct cl_io *io;
struct vvp_io *vio = NULL;
struct page *vmpage;
unsigned long ra_flags;
int result = 0;
int fault_ret = 0;
__u16 refcheck;
ENTRY;
env = cl_env_get(&refcheck);
if (IS_ERR(env))
RETURN(PTR_ERR(env));
if (ll_sbi_has_fast_read(ll_i2sbi(file_inode(vma->vm_file)))) {
/* do fast fault */
ll_cl_add(vma->vm_file, env, NULL, LCC_MMAP);
fault_ret = filemap_fault(vma, vmf);
ll_cl_remove(vma->vm_file, env);
/* - If there is no error, then the page was found in cache and
* uptodate;
* - If VM_FAULT_RETRY is set, the page existed but failed to
* lock. It will return to kernel and retry;
* - Otherwise, it should try normal fault under DLM lock. */
if ((fault_ret & VM_FAULT_RETRY) ||
!(fault_ret & VM_FAULT_ERROR))
GOTO(out, result = 0);
fault_ret = 0;
}
io = ll_fault_io_init(env, vma, vmf->pgoff, &ra_flags);
if (IS_ERR(io))
GOTO(out, result = PTR_ERR(io));
result = io->ci_result;
if (result == 0) {
vio = vvp_env_io(env);
vio->u.fault.ft_vma = vma;
vio->u.fault.ft_vmpage = NULL;
vio->u.fault.ft_vmf = vmf;
vio->u.fault.ft_flags = 0;
vio->u.fault.ft_flags_valid = 0;
/* May call ll_readpage() */
ll_cl_add(vma->vm_file, env, io, LCC_MMAP);
result = cl_io_loop(env, io);
ll_cl_remove(vma->vm_file, env);
/* ft_flags are only valid if we reached
* the call to filemap_fault */
if (vio->u.fault.ft_flags_valid)
fault_ret = vio->u.fault.ft_flags;
vmpage = vio->u.fault.ft_vmpage;
if (result != 0 && vmpage != NULL) {
put_page(vmpage);
vmf->page = NULL;
}
}
cl_io_fini(env, io);
vma->vm_flags |= ra_flags;
out:
cl_env_put(env, &refcheck);
if (result != 0 && !(fault_ret & VM_FAULT_RETRY))
fault_ret |= to_fault_error(result);
CDEBUG(D_MMAP, "%s fault %d/%d\n", current->comm, fault_ret, result);
RETURN(fault_ret);
}