diff options
Diffstat (limited to 'drivers/staging/lustre/lustre/llite/llite_mmap.c')
-rw-r--r-- | drivers/staging/lustre/lustre/llite/llite_mmap.c | 492 |
1 files changed, 492 insertions, 0 deletions
diff --git a/drivers/staging/lustre/lustre/llite/llite_mmap.c b/drivers/staging/lustre/lustre/llite/llite_mmap.c new file mode 100644 index 000000000..a90214bb8 --- /dev/null +++ b/drivers/staging/lustre/lustre/llite/llite_mmap.c @@ -0,0 +1,492 @@ +/* + * GPL HEADER START + * + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 only, + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License version 2 for more details (a copy is included + * in the LICENSE file that accompanied this code). + * + * You should have received a copy of the GNU General Public License + * version 2 along with this program; If not, see + * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf + * + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + * GPL HEADER END + */ +/* + * Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved. + * Use is subject to license terms. + * + * Copyright (c) 2011, 2012, Intel Corporation. + */ +/* + * This file is part of Lustre, http://www.lustre.org/ + * Lustre is a trademark of Sun Microsystems, Inc. + */ + +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/string.h> +#include <linux/stat.h> +#include <linux/errno.h> +#include <linux/unistd.h> +#include <linux/uaccess.h> + +#include <linux/fs.h> +#include <linux/pagemap.h> + +#define DEBUG_SUBSYSTEM S_LLITE + +#include "../include/lustre_lite.h" +#include "llite_internal.h" +#include "../include/linux/lustre_compat25.h" + +static const struct vm_operations_struct ll_file_vm_ops; + +void policy_from_vma(ldlm_policy_data_t *policy, + struct vm_area_struct *vma, unsigned long addr, + size_t count) +{ + policy->l_extent.start = ((addr - vma->vm_start) & CFS_PAGE_MASK) + + (vma->vm_pgoff << PAGE_CACHE_SHIFT); + policy->l_extent.end = (policy->l_extent.start + count - 1) | + ~CFS_PAGE_MASK; +} + +struct vm_area_struct *our_vma(struct mm_struct *mm, unsigned long addr, + size_t count) +{ + struct vm_area_struct *vma, *ret = NULL; + + /* mmap_sem must have been held by caller. */ + LASSERT(!down_write_trylock(&mm->mmap_sem)); + + for (vma = find_vma(mm, addr); + vma != NULL && vma->vm_start < (addr + count); vma = vma->vm_next) { + if (vma->vm_ops && vma->vm_ops == &ll_file_vm_ops && + vma->vm_flags & VM_SHARED) { + ret = vma; + break; + } + } + return ret; +} + +/** + * API independent part for page fault initialization. + * \param vma - virtual memory area addressed to page fault + * \param env - corespondent lu_env to processing + * \param nest - nested level + * \param index - page index corespondent to fault. + * \parm ra_flags - vma readahead flags. + * + * \return allocated and initialized env for fault operation. + * \retval EINVAL if env can't allocated + * \return other error codes from cl_io_init. + */ +static struct cl_io * +ll_fault_io_init(struct vm_area_struct *vma, struct lu_env **env_ret, + struct cl_env_nest *nest, pgoff_t index, + unsigned long *ra_flags) +{ + struct file *file = vma->vm_file; + struct inode *inode = file_inode(file); + struct cl_io *io; + struct cl_fault_io *fio; + struct lu_env *env; + int rc; + + *env_ret = NULL; + if (ll_file_nolock(file)) + return ERR_PTR(-EOPNOTSUPP); + + /* + * page fault can be called when lustre IO is + * already active for the current thread, e.g., when doing read/write + * against user level buffer mapped from Lustre buffer. To avoid + * stomping on existing context, optionally force an allocation of a new + * one. + */ + env = cl_env_nested_get(nest); + if (IS_ERR(env)) + return ERR_PTR(-EINVAL); + + *env_ret = env; + + io = ccc_env_thread_io(env); + io->ci_obj = ll_i2info(inode)->lli_clob; + LASSERT(io->ci_obj != NULL); + + fio = &io->u.ci_fault; + fio->ft_index = index; + fio->ft_executable = vma->vm_flags&VM_EXEC; + + /* + * disable VM_SEQ_READ and use VM_RAND_READ to make sure that + * the kernel will not read other pages not covered by ldlm in + * filemap_nopage. we do our readahead in ll_readpage. + */ + if (ra_flags != NULL) + *ra_flags = vma->vm_flags & (VM_RAND_READ|VM_SEQ_READ); + vma->vm_flags &= ~VM_SEQ_READ; + vma->vm_flags |= VM_RAND_READ; + + CDEBUG(D_MMAP, "vm_flags: %lx (%lu %d)\n", vma->vm_flags, + fio->ft_index, fio->ft_executable); + + rc = cl_io_init(env, io, CIT_FAULT, io->ci_obj); + if (rc == 0) { + struct ccc_io *cio = ccc_env_io(env); + struct ll_file_data *fd = LUSTRE_FPRIVATE(file); + + LASSERT(cio->cui_cl.cis_io == io); + + /* mmap lock must be MANDATORY it has to cache + * pages. */ + io->ci_lockreq = CILR_MANDATORY; + cio->cui_fd = fd; + } else { + LASSERT(rc < 0); + cl_io_fini(env, io); + cl_env_nested_put(nest, env); + io = ERR_PTR(rc); + } + + return io; +} + +/* Sharing code of page_mkwrite method for rhel5 and rhel6 */ +static int ll_page_mkwrite0(struct vm_area_struct *vma, struct page *vmpage, + bool *retry) +{ + struct lu_env *env; + struct cl_io *io; + struct vvp_io *vio; + struct cl_env_nest nest; + int result; + sigset_t set; + struct inode *inode; + struct ll_inode_info *lli; + + LASSERT(vmpage != NULL); + + io = ll_fault_io_init(vma, &env, &nest, vmpage->index, NULL); + if (IS_ERR(io)) { + result = PTR_ERR(io); + goto out; + } + + result = io->ci_result; + if (result < 0) + goto out_io; + + io->u.ci_fault.ft_mkwrite = 1; + io->u.ci_fault.ft_writable = 1; + + vio = vvp_env_io(env); + vio->u.fault.ft_vma = vma; + vio->u.fault.ft_vmpage = vmpage; + + set = cfs_block_sigsinv(sigmask(SIGKILL) | sigmask(SIGTERM)); + + /* we grab lli_trunc_sem to exclude truncate case. + * Otherwise, we could add dirty pages into osc cache + * while truncate is on-going. */ + inode = ccc_object_inode(io->ci_obj); + lli = ll_i2info(inode); + down_read(&lli->lli_trunc_sem); + + result = cl_io_loop(env, io); + + up_read(&lli->lli_trunc_sem); + + cfs_restore_sigs(set); + + if (result == 0) { + struct inode *inode = file_inode(vma->vm_file); + struct ll_inode_info *lli = ll_i2info(inode); + + lock_page(vmpage); + if (vmpage->mapping == NULL) { + unlock_page(vmpage); + + /* page was truncated and lock was cancelled, return + * ENODATA so that VM_FAULT_NOPAGE will be returned + * to handle_mm_fault(). */ + if (result == 0) + result = -ENODATA; + } else if (!PageDirty(vmpage)) { + /* race, the page has been cleaned by ptlrpcd after + * it was unlocked, it has to be added into dirty + * cache again otherwise this soon-to-dirty page won't + * consume any grants, even worse if this page is being + * transferred because it will break RPC checksum. + */ + unlock_page(vmpage); + + CDEBUG(D_MMAP, "Race on page_mkwrite %p/%lu, page has been written out, retry.\n", + vmpage, vmpage->index); + + *retry = true; + result = -EAGAIN; + } + + if (result == 0) { + spin_lock(&lli->lli_lock); + lli->lli_flags |= LLIF_DATA_MODIFIED; + spin_unlock(&lli->lli_lock); + } + } + +out_io: + cl_io_fini(env, io); + cl_env_nested_put(&nest, env); +out: + CDEBUG(D_MMAP, "%s mkwrite with %d\n", current->comm, result); + LASSERT(ergo(result == 0, PageLocked(vmpage))); + + return result; +} + + + +static inline int to_fault_error(int result) +{ + switch (result) { + case 0: + result = VM_FAULT_LOCKED; + break; + case -EFAULT: + result = VM_FAULT_NOPAGE; + break; + case -ENOMEM: + result = VM_FAULT_OOM; + break; + default: + result = VM_FAULT_SIGBUS; + break; + } + return result; +} + +/** + * 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.fault.ft_vmf = vmf; + vio->u.fault.fault.ft_flags = 0; + vio->u.fault.fault.ft_flags_valid = false; + + result = cl_io_loop(env, io); + + /* ft_flags are only valid if we reached + * the call to filemap_fault */ + if (vio->u.fault.fault.ft_flags_valid) + fault_ret = vio->u.fault.fault.ft_flags; + + vmpage = vio->u.fault.ft_vmpage; + if (result != 0 && vmpage != NULL) { + page_cache_release(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; +} + +static int ll_fault(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + int count = 0; + bool printed = false; + int result; + sigset_t set; + + /* Only SIGKILL and SIGTERM is allowed for fault/nopage/mkwrite + * so that it can be killed by admin but not cause segfault by + * other signals. */ + set = cfs_block_sigsinv(sigmask(SIGKILL) | sigmask(SIGTERM)); + +restart: + result = ll_fault0(vma, vmf); + LASSERT(!(result & VM_FAULT_LOCKED)); + if (result == 0) { + struct page *vmpage = vmf->page; + + /* check if this page has been truncated */ + lock_page(vmpage); + if (unlikely(vmpage->mapping == NULL)) { /* unlucky */ + unlock_page(vmpage); + page_cache_release(vmpage); + vmf->page = NULL; + + if (!printed && ++count > 16) { + CWARN("the page is under heavy contention, maybe your app(%s) needs revising :-)\n", + current->comm); + printed = true; + } + + goto restart; + } + + result = VM_FAULT_LOCKED; + } + cfs_restore_sigs(set); + return result; +} + +static int ll_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + int count = 0; + bool printed = false; + bool retry; + int result; + + do { + retry = false; + result = ll_page_mkwrite0(vma, vmf->page, &retry); + + if (!printed && ++count > 16) { + CWARN("app(%s): the page %lu of file %lu is under heavy contention.\n", + current->comm, vmf->pgoff, + file_inode(vma->vm_file)->i_ino); + printed = true; + } + } while (retry); + + switch (result) { + case 0: + LASSERT(PageLocked(vmf->page)); + result = VM_FAULT_LOCKED; + break; + case -ENODATA: + case -EFAULT: + result = VM_FAULT_NOPAGE; + break; + case -ENOMEM: + result = VM_FAULT_OOM; + break; + case -EAGAIN: + result = VM_FAULT_RETRY; + break; + default: + result = VM_FAULT_SIGBUS; + break; + } + + return result; +} + +/** + * To avoid cancel the locks covering mmapped region for lock cache pressure, + * we track the mapped vma count in ccc_object::cob_mmap_cnt. + */ +static void ll_vm_open(struct vm_area_struct *vma) +{ + struct inode *inode = file_inode(vma->vm_file); + struct ccc_object *vob = cl_inode2ccc(inode); + + LASSERT(vma->vm_file); + LASSERT(atomic_read(&vob->cob_mmap_cnt) >= 0); + atomic_inc(&vob->cob_mmap_cnt); +} + +/** + * Dual to ll_vm_open(). + */ +static void ll_vm_close(struct vm_area_struct *vma) +{ + struct inode *inode = file_inode(vma->vm_file); + struct ccc_object *vob = cl_inode2ccc(inode); + + LASSERT(vma->vm_file); + atomic_dec(&vob->cob_mmap_cnt); + LASSERT(atomic_read(&vob->cob_mmap_cnt) >= 0); +} + +/* XXX put nice comment here. talk about __free_pte -> dirty pages and + * nopage's reference passing to the pte */ +int ll_teardown_mmaps(struct address_space *mapping, __u64 first, __u64 last) +{ + int rc = -ENOENT; + + LASSERTF(last > first, "last %llu first %llu\n", last, first); + if (mapping_mapped(mapping)) { + rc = 0; + unmap_mapping_range(mapping, first + PAGE_CACHE_SIZE - 1, + last - first + 1, 0); + } + + return rc; +} + +static const struct vm_operations_struct ll_file_vm_ops = { + .fault = ll_fault, + .page_mkwrite = ll_page_mkwrite, + .open = ll_vm_open, + .close = ll_vm_close, +}; + +int ll_file_mmap(struct file *file, struct vm_area_struct *vma) +{ + struct inode *inode = file_inode(file); + int rc; + + if (ll_file_nolock(file)) + return -EOPNOTSUPP; + + ll_stats_ops_tally(ll_i2sbi(inode), LPROC_LL_MAP, 1); + rc = generic_file_mmap(file, vma); + if (rc == 0) { + vma->vm_ops = &ll_file_vm_ops; + vma->vm_ops->open(vma); + /* update the inode's size and mtime */ + rc = ll_glimpse_size(inode); + } + + return rc; +} |