linux/fs/ocfs2/dlm/dlmfs.c
Joel Becker d24fbcda0c ocfs2: Negotiate locking protocol versions.
Currently, when ocfs2 nodes connect via TCP, they advertise their
compatibility level.  If the versions do not match, two nodes cannot speak
to each other and they disconnect. As a result, this provides no forward or
backwards compatibility.

This patch implements a simple protocol negotiation at the dlm level by
introducing a major/minor version number scheme for entities that
communicate.  Specifically, o2dlm has a major/minor version for interaction
with o2dlm on other nodes, and ocfs2 itself has a major/minor version for
interacting with the filesystem on other nodes.

This will allow rolling upgrades of ocfs2 clusters when changes to the
locking or network protocols can be done in a backwards compatible manner.
In those cases, only the minor number is changed and the negotatied protocol
minor is returned from dlm join. In the far less likely event that a
required protocol change makes backwards compatibility impossible, we simply
bump the major number.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2008-02-06 16:11:29 -08:00

652 lines
15 KiB
C

/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* dlmfs.c
*
* 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,
* which was a template for the fs side of this module.
*
* Copyright (C) 2003, 2004 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* 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 for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
/* Simple VFS hooks based on: */
/*
* Resizable simple ram filesystem for Linux.
*
* Copyright (C) 2000 Linus Torvalds.
* 2000 Transmeta Corp.
*/
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/backing-dev.h>
#include <asm/uaccess.h>
#include "cluster/nodemanager.h"
#include "cluster/heartbeat.h"
#include "cluster/tcp.h"
#include "dlmapi.h"
#include "userdlm.h"
#include "dlmfsver.h"
#define MLOG_MASK_PREFIX ML_DLMFS
#include "cluster/masklog.h"
#include "ocfs2_lockingver.h"
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;
/*
* This is the userdlmfs locking protocol version.
*
* See fs/ocfs2/dlmglue.c for more details on locking versions.
*/
static const struct dlm_protocol_version user_locking_protocol = {
.pv_major = OCFS2_LOCKING_PROTOCOL_MAJOR,
.pv_minor = OCFS2_LOCKING_PROTOCOL_MINOR,
};
/*
* decodes a set of open flags into a valid lock level and a set of flags.
* returns < 0 if we have invalid flags
* flags which mean something to us:
* O_RDONLY -> PRMODE level
* O_WRONLY -> EXMODE level
*
* O_NONBLOCK -> LKM_NOQUEUE
*/
static int dlmfs_decode_open_flags(int open_flags,
int *level,
int *flags)
{
if (open_flags & (O_WRONLY|O_RDWR))
*level = LKM_EXMODE;
else
*level = LKM_PRMODE;
*flags = 0;
if (open_flags & O_NONBLOCK)
*flags |= LKM_NOQUEUE;
return 0;
}
static int dlmfs_file_open(struct inode *inode,
struct file *file)
{
int status, level, flags;
struct dlmfs_filp_private *fp = NULL;
struct dlmfs_inode_private *ip;
if (S_ISDIR(inode->i_mode))
BUG();
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);
if (status < 0)
goto bail;
/* We don't want to honor O_APPEND at read/write time as it
* doesn't make sense for LVB writes. */
file->f_flags &= ~O_APPEND;
fp = kmalloc(sizeof(*fp), GFP_NOFS);
if (!fp) {
status = -ENOMEM;
goto bail;
}
fp->fp_lock_level = level;
ip = DLMFS_I(inode);
status = user_dlm_cluster_lock(&ip->ip_lockres, level, flags);
if (status < 0) {
/* 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 & LKM_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, status;
struct dlmfs_inode_private *ip = DLMFS_I(inode);
struct dlmfs_filp_private *fp =
(struct dlmfs_filp_private *) file->private_data;
if (S_ISDIR(inode->i_mode))
BUG();
mlog(0, "close called on inode %lu\n", inode->i_ino);
status = 0;
if (fp) {
level = fp->fp_lock_level;
if (level != LKM_IVMODE)
user_dlm_cluster_unlock(&ip->ip_lockres, level);
kfree(fp);
file->private_data = NULL;
}
return 0;
}
static ssize_t dlmfs_file_read(struct file *filp,
char __user *buf,
size_t count,
loff_t *ppos)
{
int bytes_left;
ssize_t readlen;
char *lvb_buf;
struct inode *inode = filp->f_path.dentry->d_inode;
mlog(0, "inode %lu, count = %zu, *ppos = %llu\n",
inode->i_ino, count, *ppos);
if (*ppos >= i_size_read(inode))
return 0;
if (!count)
return 0;
if (!access_ok(VERIFY_WRITE, buf, count))
return -EFAULT;
/* don't read past the lvb */
if ((count + *ppos) > i_size_read(inode))
readlen = i_size_read(inode) - *ppos;
else
readlen = count - *ppos;
lvb_buf = kmalloc(readlen, GFP_NOFS);
if (!lvb_buf)
return -ENOMEM;
user_dlm_read_lvb(inode, lvb_buf, readlen);
bytes_left = __copy_to_user(buf, lvb_buf, readlen);
readlen -= bytes_left;
kfree(lvb_buf);
*ppos = *ppos + readlen;
mlog(0, "read %zd bytes\n", readlen);
return readlen;
}
static ssize_t dlmfs_file_write(struct file *filp,
const char __user *buf,
size_t count,
loff_t *ppos)
{
int bytes_left;
ssize_t writelen;
char *lvb_buf;
struct inode *inode = filp->f_path.dentry->d_inode;
mlog(0, "inode %lu, count = %zu, *ppos = %llu\n",
inode->i_ino, count, *ppos);
if (*ppos >= i_size_read(inode))
return -ENOSPC;
if (!count)
return 0;
if (!access_ok(VERIFY_READ, buf, count))
return -EFAULT;
/* don't write past the lvb */
if ((count + *ppos) > i_size_read(inode))
writelen = i_size_read(inode) - *ppos;
else
writelen = count - *ppos;
lvb_buf = kmalloc(writelen, GFP_NOFS);
if (!lvb_buf)
return -ENOMEM;
bytes_left = copy_from_user(lvb_buf, buf, writelen);
writelen -= bytes_left;
if (writelen)
user_dlm_write_lvb(inode, lvb_buf, writelen);
kfree(lvb_buf);
*ppos = *ppos + writelen;
mlog(0, "wrote %zd bytes\n", writelen);
return writelen;
}
static void dlmfs_init_once(struct kmem_cache *cachep,
void *foo)
{
struct dlmfs_inode_private *ip =
(struct dlmfs_inode_private *) foo;
ip->ip_dlm = NULL;
ip->ip_parent = NULL;
inode_init_once(&ip->ip_vfs_inode);
}
static struct inode *dlmfs_alloc_inode(struct super_block *sb)
{
struct dlmfs_inode_private *ip;
ip = kmem_cache_alloc(dlmfs_inode_cache, GFP_NOFS);
if (!ip)
return NULL;
return &ip->ip_vfs_inode;
}
static void dlmfs_destroy_inode(struct inode *inode)
{
kmem_cache_free(dlmfs_inode_cache, DLMFS_I(inode));
}
static void dlmfs_clear_inode(struct inode *inode)
{
int status;
struct dlmfs_inode_private *ip;
if (!inode)
return;
mlog(0, "inode %lu\n", inode->i_ino);
ip = DLMFS_I(inode);
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_dlm = 0x%p\n", ip->ip_dlm);
/* we must be a directory. If required, lets unregister the
* dlm context now. */
if (ip->ip_dlm)
user_dlm_unregister_context(ip->ip_dlm);
clear_fields:
ip->ip_parent = NULL;
ip->ip_dlm = NULL;
}
static struct backing_dev_info dlmfs_backing_dev_info = {
.ra_pages = 0, /* No readahead */
.capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
};
static struct inode *dlmfs_get_root_inode(struct super_block *sb)
{
struct inode *inode = new_inode(sb);
int mode = S_IFDIR | 0755;
struct dlmfs_inode_private *ip;
if (inode) {
ip = DLMFS_I(inode);
inode->i_mode = mode;
inode->i_uid = current->fsuid;
inode->i_gid = current->fsgid;
inode->i_blocks = 0;
inode->i_mapping->backing_dev_info = &dlmfs_backing_dev_info;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
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,
int 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_mode = mode;
inode->i_uid = current->fsuid;
inode->i_gid = current->fsgid;
inode->i_blocks = 0;
inode->i_mapping->backing_dev_info = &dlmfs_backing_dev_info;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
ip = DLMFS_I(inode);
ip->ip_dlm = DLMFS_I(parent)->ip_dlm;
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;
}
if (parent->i_mode & S_ISGID) {
inode->i_gid = parent->i_gid;
if (S_ISDIR(mode))
inode->i_mode |= S_ISGID;
}
return inode;
}
/*
* File creation. Allocate an inode, and we're done..
*/
/* SMP-safe */
static int dlmfs_mkdir(struct inode * dir,
struct dentry * dentry,
int mode)
{
int status;
struct inode *inode = NULL;
struct qstr *domain = &dentry->d_name;
struct dlmfs_inode_private *ip;
struct dlm_ctxt *dlm;
struct dlm_protocol_version proto = user_locking_protocol;
mlog(0, "mkdir %.*s\n", domain->len, domain->name);
/* verify that we have a proper domain */
if (domain->len >= O2NM_MAX_NAME_LEN) {
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);
dlm = user_dlm_register_context(domain, &proto);
if (IS_ERR(dlm)) {
status = PTR_ERR(dlm);
mlog(ML_ERROR, "Error %d could not register domain \"%.*s\"\n",
status, domain->len, domain->name);
goto bail;
}
ip->ip_dlm = dlm;
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,
int mode,
struct nameidata *nd)
{
int status = 0;
struct inode *inode;
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 = dentry->d_inode;
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 %.*s, error %d from destroy\n",
dentry->d_name.len, dentry->d_name.name, status);
goto bail;
}
status = simple_unlink(dir, dentry);
bail:
return status;
}
static int dlmfs_fill_super(struct super_block * sb,
void * data,
int silent)
{
struct inode * inode;
struct dentry * root;
sb->s_maxbytes = MAX_LFS_FILESIZE;
sb->s_blocksize = PAGE_CACHE_SIZE;
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
sb->s_magic = DLMFS_MAGIC;
sb->s_op = &dlmfs_ops;
inode = dlmfs_get_root_inode(sb);
if (!inode)
return -ENOMEM;
root = d_alloc_root(inode);
if (!root) {
iput(inode);
return -ENOMEM;
}
sb->s_root = root;
return 0;
}
static const struct file_operations dlmfs_file_operations = {
.open = dlmfs_file_open,
.release = dlmfs_file_release,
.read = dlmfs_file_read,
.write = dlmfs_file_write,
};
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,
.destroy_inode = dlmfs_destroy_inode,
.clear_inode = dlmfs_clear_inode,
.drop_inode = generic_delete_inode,
};
static const struct inode_operations dlmfs_file_inode_operations = {
.getattr = simple_getattr,
};
static int dlmfs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
return get_sb_nodev(fs_type, flags, data, dlmfs_fill_super, mnt);
}
static struct file_system_type dlmfs_fs_type = {
.owner = THIS_MODULE,
.name = "ocfs2_dlmfs",
.get_sb = dlmfs_get_sb,
.kill_sb = kill_litter_super,
};
static int __init init_dlmfs_fs(void)
{
int status;
int cleanup_inode = 0, cleanup_worker = 0;
dlmfs_print_version();
status = bdi_init(&dlmfs_backing_dev_info);
if (status)
return status;
dlmfs_inode_cache = kmem_cache_create("dlmfs_inode_cache",
sizeof(struct dlmfs_inode_private),
0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
SLAB_MEM_SPREAD),
dlmfs_init_once);
if (!dlmfs_inode_cache)
goto bail;
cleanup_inode = 1;
user_dlm_worker = create_singlethread_workqueue("user_dlm");
if (!user_dlm_worker) {
status = -ENOMEM;
goto bail;
}
cleanup_worker = 1;
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);
bdi_destroy(&dlmfs_backing_dev_info);
} else
printk("OCFS2 User DLM kernel interface loaded\n");
return status;
}
static void __exit exit_dlmfs_fs(void)
{
unregister_filesystem(&dlmfs_fs_type);
flush_workqueue(user_dlm_worker);
destroy_workqueue(user_dlm_worker);
kmem_cache_destroy(dlmfs_inode_cache);
bdi_destroy(&dlmfs_backing_dev_info);
}
MODULE_AUTHOR("Oracle");
MODULE_LICENSE("GPL");
module_init(init_dlmfs_fs)
module_exit(exit_dlmfs_fs)