// SPDX-License-Identifier: GPL-2.0-or-later
|
/* -*- mode: c; c-basic-offset: 8; -*-
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* vim: noexpandtab sw=8 ts=8 sts=0:
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*
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* dlmfs.c
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*
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* Code which implements the kernel side of a minimal userspace
|
* interface to our DLM. This file handles the virtual file system
|
* used for communication with userspace. Credit should go to ramfs,
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* which was a template for the fs side of this module.
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*
|
* Copyright (C) 2003, 2004 Oracle. All rights reserved.
|
*/
|
|
/* Simple VFS hooks based on: */
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/*
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* Resizable simple ram filesystem for Linux.
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*
|
* Copyright (C) 2000 Linus Torvalds.
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* 2000 Transmeta Corp.
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*/
|
|
#include <linux/module.h>
|
#include <linux/fs.h>
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#include <linux/pagemap.h>
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#include <linux/types.h>
|
#include <linux/slab.h>
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#include <linux/highmem.h>
|
#include <linux/init.h>
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#include <linux/string.h>
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#include <linux/backing-dev.h>
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#include <linux/poll.h>
|
|
#include <linux/uaccess.h>
|
|
#include "../stackglue.h"
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#include "userdlm.h"
|
|
#define MLOG_MASK_PREFIX ML_DLMFS
|
#include "../cluster/masklog.h"
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|
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static const struct super_operations dlmfs_ops;
|
static const struct file_operations dlmfs_file_operations;
|
static const struct inode_operations dlmfs_dir_inode_operations;
|
static const struct inode_operations dlmfs_root_inode_operations;
|
static const struct inode_operations dlmfs_file_inode_operations;
|
static struct kmem_cache *dlmfs_inode_cache;
|
|
struct workqueue_struct *user_dlm_worker;
|
|
|
|
/*
|
* These are the ABI capabilities of dlmfs.
|
*
|
* Over time, dlmfs has added some features that were not part of the
|
* initial ABI. Unfortunately, some of these features are not detectable
|
* via standard usage. For example, Linux's default poll always returns
|
* EPOLLIN, so there is no way for a caller of poll(2) to know when dlmfs
|
* added poll support. Instead, we provide this list of new capabilities.
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*
|
* Capabilities is a read-only attribute. We do it as a module parameter
|
* so we can discover it whether dlmfs is built in, loaded, or even not
|
* loaded.
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*
|
* The ABI features are local to this machine's dlmfs mount. This is
|
* distinct from the locking protocol, which is concerned with inter-node
|
* interaction.
|
*
|
* Capabilities:
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* - bast : EPOLLIN against the file descriptor of a held lock
|
* signifies a bast fired on the lock.
|
*/
|
#define DLMFS_CAPABILITIES "bast stackglue"
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static int param_set_dlmfs_capabilities(const char *val,
|
const struct kernel_param *kp)
|
{
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printk(KERN_ERR "%s: readonly parameter\n", kp->name);
|
return -EINVAL;
|
}
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static int param_get_dlmfs_capabilities(char *buffer,
|
const struct kernel_param *kp)
|
{
|
return strlcpy(buffer, DLMFS_CAPABILITIES,
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strlen(DLMFS_CAPABILITIES) + 1);
|
}
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module_param_call(capabilities, param_set_dlmfs_capabilities,
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param_get_dlmfs_capabilities, NULL, 0444);
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MODULE_PARM_DESC(capabilities, DLMFS_CAPABILITIES);
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|
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/*
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* decodes a set of open flags into a valid lock level and a set of flags.
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* returns < 0 if we have invalid flags
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* flags which mean something to us:
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* O_RDONLY -> PRMODE level
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* O_WRONLY -> EXMODE level
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*
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* O_NONBLOCK -> NOQUEUE
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*/
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static int dlmfs_decode_open_flags(int open_flags,
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int *level,
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int *flags)
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{
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if (open_flags & (O_WRONLY|O_RDWR))
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*level = DLM_LOCK_EX;
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else
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*level = DLM_LOCK_PR;
|
|
*flags = 0;
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if (open_flags & O_NONBLOCK)
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*flags |= DLM_LKF_NOQUEUE;
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|
return 0;
|
}
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|
static int dlmfs_file_open(struct inode *inode,
|
struct file *file)
|
{
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int status, level, flags;
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struct dlmfs_filp_private *fp = NULL;
|
struct dlmfs_inode_private *ip;
|
|
if (S_ISDIR(inode->i_mode))
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BUG();
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mlog(0, "open called on inode %lu, flags 0x%x\n", inode->i_ino,
|
file->f_flags);
|
|
status = dlmfs_decode_open_flags(file->f_flags, &level, &flags);
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if (status < 0)
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goto bail;
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|
/* We don't want to honor O_APPEND at read/write time as it
|
* doesn't make sense for LVB writes. */
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file->f_flags &= ~O_APPEND;
|
|
fp = kmalloc(sizeof(*fp), GFP_NOFS);
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if (!fp) {
|
status = -ENOMEM;
|
goto bail;
|
}
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fp->fp_lock_level = level;
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|
ip = DLMFS_I(inode);
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|
status = user_dlm_cluster_lock(&ip->ip_lockres, level, flags);
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if (status < 0) {
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/* this is a strange error to return here but I want
|
* to be able userspace to be able to distinguish a
|
* valid lock request from one that simply couldn't be
|
* granted. */
|
if (flags & DLM_LKF_NOQUEUE && status == -EAGAIN)
|
status = -ETXTBSY;
|
kfree(fp);
|
goto bail;
|
}
|
|
file->private_data = fp;
|
bail:
|
return status;
|
}
|
|
static int dlmfs_file_release(struct inode *inode,
|
struct file *file)
|
{
|
int level;
|
struct dlmfs_inode_private *ip = DLMFS_I(inode);
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struct dlmfs_filp_private *fp = file->private_data;
|
|
if (S_ISDIR(inode->i_mode))
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BUG();
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|
mlog(0, "close called on inode %lu\n", inode->i_ino);
|
|
if (fp) {
|
level = fp->fp_lock_level;
|
if (level != DLM_LOCK_IV)
|
user_dlm_cluster_unlock(&ip->ip_lockres, level);
|
|
kfree(fp);
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file->private_data = NULL;
|
}
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|
return 0;
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}
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|
/*
|
* We do ->setattr() just to override size changes. Our size is the size
|
* of the LVB and nothing else.
|
*/
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static int dlmfs_file_setattr(struct dentry *dentry, struct iattr *attr)
|
{
|
int error;
|
struct inode *inode = d_inode(dentry);
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|
attr->ia_valid &= ~ATTR_SIZE;
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error = setattr_prepare(dentry, attr);
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if (error)
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return error;
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setattr_copy(inode, attr);
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mark_inode_dirty(inode);
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return 0;
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}
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static __poll_t dlmfs_file_poll(struct file *file, poll_table *wait)
|
{
|
__poll_t event = 0;
|
struct inode *inode = file_inode(file);
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struct dlmfs_inode_private *ip = DLMFS_I(inode);
|
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poll_wait(file, &ip->ip_lockres.l_event, wait);
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spin_lock(&ip->ip_lockres.l_lock);
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if (ip->ip_lockres.l_flags & USER_LOCK_BLOCKED)
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event = EPOLLIN | EPOLLRDNORM;
|
spin_unlock(&ip->ip_lockres.l_lock);
|
|
return event;
|
}
|
|
static ssize_t dlmfs_file_read(struct file *file,
|
char __user *buf,
|
size_t count,
|
loff_t *ppos)
|
{
|
char lvb[DLM_LVB_LEN];
|
|
if (!user_dlm_read_lvb(file_inode(file), lvb))
|
return 0;
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return simple_read_from_buffer(buf, count, ppos, lvb, sizeof(lvb));
|
}
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|
static ssize_t dlmfs_file_write(struct file *filp,
|
const char __user *buf,
|
size_t count,
|
loff_t *ppos)
|
{
|
char lvb_buf[DLM_LVB_LEN];
|
int bytes_left;
|
struct inode *inode = file_inode(filp);
|
|
mlog(0, "inode %lu, count = %zu, *ppos = %llu\n",
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inode->i_ino, count, *ppos);
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if (*ppos >= DLM_LVB_LEN)
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return -ENOSPC;
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|
/* don't write past the lvb */
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if (count > DLM_LVB_LEN - *ppos)
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count = DLM_LVB_LEN - *ppos;
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|
if (!count)
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return 0;
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bytes_left = copy_from_user(lvb_buf, buf, count);
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count -= bytes_left;
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if (count)
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user_dlm_write_lvb(inode, lvb_buf, count);
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|
*ppos = *ppos + count;
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mlog(0, "wrote %zu bytes\n", count);
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return count;
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}
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static void dlmfs_init_once(void *foo)
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{
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struct dlmfs_inode_private *ip =
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(struct dlmfs_inode_private *) foo;
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ip->ip_conn = NULL;
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ip->ip_parent = NULL;
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inode_init_once(&ip->ip_vfs_inode);
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}
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static struct inode *dlmfs_alloc_inode(struct super_block *sb)
|
{
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struct dlmfs_inode_private *ip;
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ip = kmem_cache_alloc(dlmfs_inode_cache, GFP_NOFS);
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if (!ip)
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return NULL;
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return &ip->ip_vfs_inode;
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}
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static void dlmfs_free_inode(struct inode *inode)
|
{
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kmem_cache_free(dlmfs_inode_cache, DLMFS_I(inode));
|
}
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static void dlmfs_evict_inode(struct inode *inode)
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{
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int status;
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struct dlmfs_inode_private *ip;
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|
clear_inode(inode);
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mlog(0, "inode %lu\n", inode->i_ino);
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|
ip = DLMFS_I(inode);
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if (S_ISREG(inode->i_mode)) {
|
status = user_dlm_destroy_lock(&ip->ip_lockres);
|
if (status < 0)
|
mlog_errno(status);
|
iput(ip->ip_parent);
|
goto clear_fields;
|
}
|
|
mlog(0, "we're a directory, ip->ip_conn = 0x%p\n", ip->ip_conn);
|
/* we must be a directory. If required, lets unregister the
|
* dlm context now. */
|
if (ip->ip_conn)
|
user_dlm_unregister(ip->ip_conn);
|
clear_fields:
|
ip->ip_parent = NULL;
|
ip->ip_conn = NULL;
|
}
|
|
static struct inode *dlmfs_get_root_inode(struct super_block *sb)
|
{
|
struct inode *inode = new_inode(sb);
|
umode_t mode = S_IFDIR | 0755;
|
|
if (inode) {
|
inode->i_ino = get_next_ino();
|
inode_init_owner(inode, NULL, mode);
|
inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
|
inc_nlink(inode);
|
|
inode->i_fop = &simple_dir_operations;
|
inode->i_op = &dlmfs_root_inode_operations;
|
}
|
|
return inode;
|
}
|
|
static struct inode *dlmfs_get_inode(struct inode *parent,
|
struct dentry *dentry,
|
umode_t mode)
|
{
|
struct super_block *sb = parent->i_sb;
|
struct inode * inode = new_inode(sb);
|
struct dlmfs_inode_private *ip;
|
|
if (!inode)
|
return NULL;
|
|
inode->i_ino = get_next_ino();
|
inode_init_owner(inode, parent, mode);
|
inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
|
|
ip = DLMFS_I(inode);
|
ip->ip_conn = DLMFS_I(parent)->ip_conn;
|
|
switch (mode & S_IFMT) {
|
default:
|
/* for now we don't support anything other than
|
* directories and regular files. */
|
BUG();
|
break;
|
case S_IFREG:
|
inode->i_op = &dlmfs_file_inode_operations;
|
inode->i_fop = &dlmfs_file_operations;
|
|
i_size_write(inode, DLM_LVB_LEN);
|
|
user_dlm_lock_res_init(&ip->ip_lockres, dentry);
|
|
/* released at clear_inode time, this insures that we
|
* get to drop the dlm reference on each lock *before*
|
* we call the unregister code for releasing parent
|
* directories. */
|
ip->ip_parent = igrab(parent);
|
BUG_ON(!ip->ip_parent);
|
break;
|
case S_IFDIR:
|
inode->i_op = &dlmfs_dir_inode_operations;
|
inode->i_fop = &simple_dir_operations;
|
|
/* directory inodes start off with i_nlink ==
|
* 2 (for "." entry) */
|
inc_nlink(inode);
|
break;
|
}
|
return inode;
|
}
|
|
/*
|
* File creation. Allocate an inode, and we're done..
|
*/
|
/* SMP-safe */
|
static int dlmfs_mkdir(struct inode * dir,
|
struct dentry * dentry,
|
umode_t mode)
|
{
|
int status;
|
struct inode *inode = NULL;
|
const struct qstr *domain = &dentry->d_name;
|
struct dlmfs_inode_private *ip;
|
struct ocfs2_cluster_connection *conn;
|
|
mlog(0, "mkdir %.*s\n", domain->len, domain->name);
|
|
/* verify that we have a proper domain */
|
if (domain->len >= GROUP_NAME_MAX) {
|
status = -EINVAL;
|
mlog(ML_ERROR, "invalid domain name for directory.\n");
|
goto bail;
|
}
|
|
inode = dlmfs_get_inode(dir, dentry, mode | S_IFDIR);
|
if (!inode) {
|
status = -ENOMEM;
|
mlog_errno(status);
|
goto bail;
|
}
|
|
ip = DLMFS_I(inode);
|
|
conn = user_dlm_register(domain);
|
if (IS_ERR(conn)) {
|
status = PTR_ERR(conn);
|
mlog(ML_ERROR, "Error %d could not register domain \"%.*s\"\n",
|
status, domain->len, domain->name);
|
goto bail;
|
}
|
ip->ip_conn = conn;
|
|
inc_nlink(dir);
|
d_instantiate(dentry, inode);
|
dget(dentry); /* Extra count - pin the dentry in core */
|
|
status = 0;
|
bail:
|
if (status < 0)
|
iput(inode);
|
return status;
|
}
|
|
static int dlmfs_create(struct inode *dir,
|
struct dentry *dentry,
|
umode_t mode,
|
bool excl)
|
{
|
int status = 0;
|
struct inode *inode;
|
const struct qstr *name = &dentry->d_name;
|
|
mlog(0, "create %.*s\n", name->len, name->name);
|
|
/* verify name is valid and doesn't contain any dlm reserved
|
* characters */
|
if (name->len >= USER_DLM_LOCK_ID_MAX_LEN ||
|
name->name[0] == '$') {
|
status = -EINVAL;
|
mlog(ML_ERROR, "invalid lock name, %.*s\n", name->len,
|
name->name);
|
goto bail;
|
}
|
|
inode = dlmfs_get_inode(dir, dentry, mode | S_IFREG);
|
if (!inode) {
|
status = -ENOMEM;
|
mlog_errno(status);
|
goto bail;
|
}
|
|
d_instantiate(dentry, inode);
|
dget(dentry); /* Extra count - pin the dentry in core */
|
bail:
|
return status;
|
}
|
|
static int dlmfs_unlink(struct inode *dir,
|
struct dentry *dentry)
|
{
|
int status;
|
struct inode *inode = d_inode(dentry);
|
|
mlog(0, "unlink inode %lu\n", inode->i_ino);
|
|
/* if there are no current holders, or none that are waiting
|
* to acquire a lock, this basically destroys our lockres. */
|
status = user_dlm_destroy_lock(&DLMFS_I(inode)->ip_lockres);
|
if (status < 0) {
|
mlog(ML_ERROR, "unlink %pd, error %d from destroy\n",
|
dentry, status);
|
goto bail;
|
}
|
status = simple_unlink(dir, dentry);
|
bail:
|
return status;
|
}
|
|
static int dlmfs_fill_super(struct super_block * sb,
|
void * data,
|
int silent)
|
{
|
sb->s_maxbytes = MAX_LFS_FILESIZE;
|
sb->s_blocksize = PAGE_SIZE;
|
sb->s_blocksize_bits = PAGE_SHIFT;
|
sb->s_magic = DLMFS_MAGIC;
|
sb->s_op = &dlmfs_ops;
|
sb->s_root = d_make_root(dlmfs_get_root_inode(sb));
|
if (!sb->s_root)
|
return -ENOMEM;
|
return 0;
|
}
|
|
static const struct file_operations dlmfs_file_operations = {
|
.open = dlmfs_file_open,
|
.release = dlmfs_file_release,
|
.poll = dlmfs_file_poll,
|
.read = dlmfs_file_read,
|
.write = dlmfs_file_write,
|
.llseek = default_llseek,
|
};
|
|
static const struct inode_operations dlmfs_dir_inode_operations = {
|
.create = dlmfs_create,
|
.lookup = simple_lookup,
|
.unlink = dlmfs_unlink,
|
};
|
|
/* this way we can restrict mkdir to only the toplevel of the fs. */
|
static const struct inode_operations dlmfs_root_inode_operations = {
|
.lookup = simple_lookup,
|
.mkdir = dlmfs_mkdir,
|
.rmdir = simple_rmdir,
|
};
|
|
static const struct super_operations dlmfs_ops = {
|
.statfs = simple_statfs,
|
.alloc_inode = dlmfs_alloc_inode,
|
.free_inode = dlmfs_free_inode,
|
.evict_inode = dlmfs_evict_inode,
|
.drop_inode = generic_delete_inode,
|
};
|
|
static const struct inode_operations dlmfs_file_inode_operations = {
|
.getattr = simple_getattr,
|
.setattr = dlmfs_file_setattr,
|
};
|
|
static struct dentry *dlmfs_mount(struct file_system_type *fs_type,
|
int flags, const char *dev_name, void *data)
|
{
|
return mount_nodev(fs_type, flags, data, dlmfs_fill_super);
|
}
|
|
static struct file_system_type dlmfs_fs_type = {
|
.owner = THIS_MODULE,
|
.name = "ocfs2_dlmfs",
|
.mount = dlmfs_mount,
|
.kill_sb = kill_litter_super,
|
};
|
MODULE_ALIAS_FS("ocfs2_dlmfs");
|
|
static int __init init_dlmfs_fs(void)
|
{
|
int status;
|
int cleanup_inode = 0, cleanup_worker = 0;
|
|
dlmfs_inode_cache = kmem_cache_create("dlmfs_inode_cache",
|
sizeof(struct dlmfs_inode_private),
|
0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
|
SLAB_MEM_SPREAD|SLAB_ACCOUNT),
|
dlmfs_init_once);
|
if (!dlmfs_inode_cache) {
|
status = -ENOMEM;
|
goto bail;
|
}
|
cleanup_inode = 1;
|
|
user_dlm_worker = alloc_workqueue("user_dlm", WQ_MEM_RECLAIM, 0);
|
if (!user_dlm_worker) {
|
status = -ENOMEM;
|
goto bail;
|
}
|
cleanup_worker = 1;
|
|
user_dlm_set_locking_protocol();
|
status = register_filesystem(&dlmfs_fs_type);
|
bail:
|
if (status) {
|
if (cleanup_inode)
|
kmem_cache_destroy(dlmfs_inode_cache);
|
if (cleanup_worker)
|
destroy_workqueue(user_dlm_worker);
|
} else
|
printk("OCFS2 User DLM kernel interface loaded\n");
|
return status;
|
}
|
|
static void __exit exit_dlmfs_fs(void)
|
{
|
unregister_filesystem(&dlmfs_fs_type);
|
|
destroy_workqueue(user_dlm_worker);
|
|
/*
|
* Make sure all delayed rcu free inodes are flushed before we
|
* destroy cache.
|
*/
|
rcu_barrier();
|
kmem_cache_destroy(dlmfs_inode_cache);
|
|
}
|
|
MODULE_AUTHOR("Oracle");
|
MODULE_LICENSE("GPL");
|
MODULE_IMPORT_NS(ANDROID_GKI_VFS_EXPORT_ONLY);
|
MODULE_DESCRIPTION("OCFS2 DLM-Filesystem");
|
|
module_init(init_dlmfs_fs)
|
module_exit(exit_dlmfs_fs)
|
