493 lines
12 KiB
C
493 lines
12 KiB
C
/*
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* GPL HEADER START
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*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 only,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License version 2 for more details (a copy is included
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* in the LICENSE file that accompanied this code).
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*
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* You should have received a copy of the GNU General Public License
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* version 2 along with this program; If not, see
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* http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
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*
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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* CA 95054 USA or visit www.sun.com if you need additional information or
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* have any questions.
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*
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* GPL HEADER END
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*/
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/*
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* Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
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* Use is subject to license terms.
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*
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* Copyright (c) 2011, 2015, Intel Corporation.
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*/
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/*
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* This file is part of Lustre, http://www.lustre.org/
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* Lustre is a trademark of Sun Microsystems, Inc.
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*/
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <linux/stat.h>
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#include <linux/errno.h>
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#include <linux/unistd.h>
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#include <linux/uaccess.h>
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#include <linux/fs.h>
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#include <linux/pagemap.h>
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#define DEBUG_SUBSYSTEM S_LLITE
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#include "../include/lustre_lite.h"
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#include "llite_internal.h"
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#include "../include/linux/lustre_compat25.h"
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static const struct vm_operations_struct ll_file_vm_ops;
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void policy_from_vma(ldlm_policy_data_t *policy,
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struct vm_area_struct *vma, unsigned long addr,
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size_t count)
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{
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policy->l_extent.start = ((addr - vma->vm_start) & CFS_PAGE_MASK) +
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(vma->vm_pgoff << PAGE_SHIFT);
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policy->l_extent.end = (policy->l_extent.start + count - 1) |
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~CFS_PAGE_MASK;
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}
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struct vm_area_struct *our_vma(struct mm_struct *mm, unsigned long addr,
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size_t count)
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{
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struct vm_area_struct *vma, *ret = NULL;
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/* mmap_sem must have been held by caller. */
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LASSERT(!down_write_trylock(&mm->mmap_sem));
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for (vma = find_vma(mm, addr);
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vma && vma->vm_start < (addr + count); vma = vma->vm_next) {
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if (vma->vm_ops && vma->vm_ops == &ll_file_vm_ops &&
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vma->vm_flags & VM_SHARED) {
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ret = vma;
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break;
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}
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}
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return ret;
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}
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/**
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* API independent part for page fault initialization.
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* \param vma - virtual memory area addressed to page fault
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* \param env - corespondent lu_env to processing
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* \param nest - nested level
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* \param index - page index corespondent to fault.
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* \parm ra_flags - vma readahead flags.
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*
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* \return allocated and initialized env for fault operation.
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* \retval EINVAL if env can't allocated
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* \return other error codes from cl_io_init.
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*/
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static struct cl_io *
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ll_fault_io_init(struct vm_area_struct *vma, struct lu_env **env_ret,
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struct cl_env_nest *nest, pgoff_t index,
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unsigned long *ra_flags)
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{
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struct file *file = vma->vm_file;
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struct inode *inode = file_inode(file);
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struct cl_io *io;
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struct cl_fault_io *fio;
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struct lu_env *env;
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int rc;
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*env_ret = NULL;
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if (ll_file_nolock(file))
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return ERR_PTR(-EOPNOTSUPP);
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/*
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* page fault can be called when lustre IO is
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* already active for the current thread, e.g., when doing read/write
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* against user level buffer mapped from Lustre buffer. To avoid
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* stomping on existing context, optionally force an allocation of a new
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* one.
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*/
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env = cl_env_nested_get(nest);
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if (IS_ERR(env))
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return ERR_PTR(-EINVAL);
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*env_ret = env;
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io = ccc_env_thread_io(env);
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io->ci_obj = ll_i2info(inode)->lli_clob;
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LASSERT(io->ci_obj);
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fio = &io->u.ci_fault;
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fio->ft_index = index;
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fio->ft_executable = vma->vm_flags&VM_EXEC;
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/*
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* disable VM_SEQ_READ and use VM_RAND_READ to make sure that
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* the kernel will not read other pages not covered by ldlm in
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* filemap_nopage. we do our readahead in ll_readpage.
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*/
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if (ra_flags)
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*ra_flags = vma->vm_flags & (VM_RAND_READ|VM_SEQ_READ);
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vma->vm_flags &= ~VM_SEQ_READ;
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vma->vm_flags |= VM_RAND_READ;
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CDEBUG(D_MMAP, "vm_flags: %lx (%lu %d)\n", vma->vm_flags,
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fio->ft_index, fio->ft_executable);
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rc = cl_io_init(env, io, CIT_FAULT, io->ci_obj);
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if (rc == 0) {
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struct ccc_io *cio = ccc_env_io(env);
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struct ll_file_data *fd = LUSTRE_FPRIVATE(file);
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LASSERT(cio->cui_cl.cis_io == io);
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/* mmap lock must be MANDATORY it has to cache pages. */
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io->ci_lockreq = CILR_MANDATORY;
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cio->cui_fd = fd;
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} else {
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LASSERT(rc < 0);
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cl_io_fini(env, io);
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cl_env_nested_put(nest, env);
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io = ERR_PTR(rc);
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}
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return io;
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}
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/* Sharing code of page_mkwrite method for rhel5 and rhel6 */
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static int ll_page_mkwrite0(struct vm_area_struct *vma, struct page *vmpage,
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bool *retry)
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{
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struct lu_env *env;
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struct cl_io *io;
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struct vvp_io *vio;
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struct cl_env_nest nest;
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int result;
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sigset_t set;
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struct inode *inode;
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struct ll_inode_info *lli;
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io = ll_fault_io_init(vma, &env, &nest, vmpage->index, NULL);
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if (IS_ERR(io)) {
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result = PTR_ERR(io);
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goto out;
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}
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result = io->ci_result;
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if (result < 0)
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goto out_io;
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io->u.ci_fault.ft_mkwrite = 1;
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io->u.ci_fault.ft_writable = 1;
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vio = vvp_env_io(env);
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vio->u.fault.ft_vma = vma;
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vio->u.fault.ft_vmpage = vmpage;
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set = cfs_block_sigsinv(sigmask(SIGKILL) | sigmask(SIGTERM));
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/* we grab lli_trunc_sem to exclude truncate case.
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* Otherwise, we could add dirty pages into osc cache
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* while truncate is on-going.
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*/
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inode = ccc_object_inode(io->ci_obj);
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lli = ll_i2info(inode);
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down_read(&lli->lli_trunc_sem);
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result = cl_io_loop(env, io);
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up_read(&lli->lli_trunc_sem);
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cfs_restore_sigs(set);
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if (result == 0) {
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struct inode *inode = file_inode(vma->vm_file);
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struct ll_inode_info *lli = ll_i2info(inode);
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lock_page(vmpage);
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if (!vmpage->mapping) {
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unlock_page(vmpage);
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/* page was truncated and lock was cancelled, return
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* ENODATA so that VM_FAULT_NOPAGE will be returned
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* to handle_mm_fault().
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*/
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if (result == 0)
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result = -ENODATA;
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} else if (!PageDirty(vmpage)) {
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/* race, the page has been cleaned by ptlrpcd after
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* it was unlocked, it has to be added into dirty
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* cache again otherwise this soon-to-dirty page won't
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* consume any grants, even worse if this page is being
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* transferred because it will break RPC checksum.
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*/
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unlock_page(vmpage);
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CDEBUG(D_MMAP, "Race on page_mkwrite %p/%lu, page has been written out, retry.\n",
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vmpage, vmpage->index);
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*retry = true;
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result = -EAGAIN;
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}
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if (result == 0) {
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spin_lock(&lli->lli_lock);
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lli->lli_flags |= LLIF_DATA_MODIFIED;
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spin_unlock(&lli->lli_lock);
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}
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}
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out_io:
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cl_io_fini(env, io);
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cl_env_nested_put(&nest, env);
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out:
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CDEBUG(D_MMAP, "%s mkwrite with %d\n", current->comm, result);
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LASSERT(ergo(result == 0, PageLocked(vmpage)));
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return result;
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}
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static inline int to_fault_error(int result)
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{
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switch (result) {
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case 0:
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result = VM_FAULT_LOCKED;
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break;
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case -EFAULT:
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result = VM_FAULT_NOPAGE;
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break;
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case -ENOMEM:
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result = VM_FAULT_OOM;
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break;
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default:
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result = VM_FAULT_SIGBUS;
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break;
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}
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return result;
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}
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/**
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* Lustre implementation of a vm_operations_struct::fault() method, called by
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* VM to server page fault (both in kernel and user space).
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*
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* \param vma - is virtual area struct related to page fault
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* \param vmf - structure which describe type and address where hit fault
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*
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* \return allocated and filled _locked_ page for address
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* \retval VM_FAULT_ERROR on general error
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* \retval NOPAGE_OOM not have memory for allocate new page
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*/
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static int ll_fault0(struct vm_area_struct *vma, struct vm_fault *vmf)
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{
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struct lu_env *env;
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struct cl_io *io;
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struct vvp_io *vio = NULL;
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struct page *vmpage;
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unsigned long ra_flags;
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struct cl_env_nest nest;
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int result;
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int fault_ret = 0;
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io = ll_fault_io_init(vma, &env, &nest, vmf->pgoff, &ra_flags);
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if (IS_ERR(io))
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return to_fault_error(PTR_ERR(io));
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result = io->ci_result;
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if (result == 0) {
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vio = vvp_env_io(env);
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vio->u.fault.ft_vma = vma;
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vio->u.fault.ft_vmpage = NULL;
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vio->u.fault.fault.ft_vmf = vmf;
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vio->u.fault.fault.ft_flags = 0;
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vio->u.fault.fault.ft_flags_valid = false;
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result = cl_io_loop(env, io);
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/* ft_flags are only valid if we reached
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* the call to filemap_fault
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*/
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if (vio->u.fault.fault.ft_flags_valid)
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fault_ret = vio->u.fault.fault.ft_flags;
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vmpage = vio->u.fault.ft_vmpage;
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if (result != 0 && vmpage) {
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put_page(vmpage);
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vmf->page = NULL;
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}
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}
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cl_io_fini(env, io);
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cl_env_nested_put(&nest, env);
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vma->vm_flags |= ra_flags;
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if (result != 0 && !(fault_ret & VM_FAULT_RETRY))
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fault_ret |= to_fault_error(result);
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CDEBUG(D_MMAP, "%s fault %d/%d\n",
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current->comm, fault_ret, result);
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return fault_ret;
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}
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static int ll_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
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{
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int count = 0;
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bool printed = false;
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int result;
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sigset_t set;
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/* Only SIGKILL and SIGTERM are allowed for fault/nopage/mkwrite
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* so that it can be killed by admin but not cause segfault by
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* other signals.
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*/
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set = cfs_block_sigsinv(sigmask(SIGKILL) | sigmask(SIGTERM));
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restart:
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result = ll_fault0(vma, vmf);
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LASSERT(!(result & VM_FAULT_LOCKED));
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if (result == 0) {
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struct page *vmpage = vmf->page;
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/* check if this page has been truncated */
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lock_page(vmpage);
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if (unlikely(!vmpage->mapping)) { /* unlucky */
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unlock_page(vmpage);
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put_page(vmpage);
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vmf->page = NULL;
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if (!printed && ++count > 16) {
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CWARN("the page is under heavy contention, maybe your app(%s) needs revising :-)\n",
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current->comm);
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printed = true;
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}
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goto restart;
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}
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result = VM_FAULT_LOCKED;
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}
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cfs_restore_sigs(set);
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return result;
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}
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static int ll_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
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{
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int count = 0;
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bool printed = false;
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bool retry;
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int result;
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do {
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retry = false;
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result = ll_page_mkwrite0(vma, vmf->page, &retry);
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if (!printed && ++count > 16) {
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CWARN("app(%s): the page %lu of file %lu is under heavy contention.\n",
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current->comm, vmf->pgoff,
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file_inode(vma->vm_file)->i_ino);
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printed = true;
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}
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} while (retry);
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switch (result) {
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case 0:
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LASSERT(PageLocked(vmf->page));
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result = VM_FAULT_LOCKED;
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break;
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case -ENODATA:
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case -EFAULT:
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result = VM_FAULT_NOPAGE;
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break;
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case -ENOMEM:
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result = VM_FAULT_OOM;
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break;
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case -EAGAIN:
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result = VM_FAULT_RETRY;
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break;
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default:
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result = VM_FAULT_SIGBUS;
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break;
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}
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return result;
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}
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/**
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* To avoid cancel the locks covering mmapped region for lock cache pressure,
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* we track the mapped vma count in ccc_object::cob_mmap_cnt.
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*/
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static void ll_vm_open(struct vm_area_struct *vma)
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{
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struct inode *inode = file_inode(vma->vm_file);
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struct ccc_object *vob = cl_inode2ccc(inode);
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LASSERT(vma->vm_file);
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LASSERT(atomic_read(&vob->cob_mmap_cnt) >= 0);
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atomic_inc(&vob->cob_mmap_cnt);
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}
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/**
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* Dual to ll_vm_open().
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*/
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static void ll_vm_close(struct vm_area_struct *vma)
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{
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struct inode *inode = file_inode(vma->vm_file);
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struct ccc_object *vob = cl_inode2ccc(inode);
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LASSERT(vma->vm_file);
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atomic_dec(&vob->cob_mmap_cnt);
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LASSERT(atomic_read(&vob->cob_mmap_cnt) >= 0);
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}
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/* XXX put nice comment here. talk about __free_pte -> dirty pages and
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* nopage's reference passing to the pte
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*/
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int ll_teardown_mmaps(struct address_space *mapping, __u64 first, __u64 last)
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{
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int rc = -ENOENT;
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LASSERTF(last > first, "last %llu first %llu\n", last, first);
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if (mapping_mapped(mapping)) {
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rc = 0;
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unmap_mapping_range(mapping, first + PAGE_SIZE - 1,
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last - first + 1, 0);
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}
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return rc;
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}
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static const struct vm_operations_struct ll_file_vm_ops = {
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.fault = ll_fault,
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.page_mkwrite = ll_page_mkwrite,
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.open = ll_vm_open,
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.close = ll_vm_close,
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};
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int ll_file_mmap(struct file *file, struct vm_area_struct *vma)
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{
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struct inode *inode = file_inode(file);
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int rc;
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if (ll_file_nolock(file))
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return -EOPNOTSUPP;
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ll_stats_ops_tally(ll_i2sbi(inode), LPROC_LL_MAP, 1);
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rc = generic_file_mmap(file, vma);
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if (rc == 0) {
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vma->vm_ops = &ll_file_vm_ops;
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vma->vm_ops->open(vma);
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/* update the inode's size and mtime */
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rc = ll_glimpse_size(inode);
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}
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return rc;
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}
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