--- /dev/null
+/* -*- 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 <linux/poll.h>
+
+#include <asm/uaccess.h>
+
+#include "stackglue.h"
+#include "userdlm.h"
+
+#define MLOG_MASK_PREFIX ML_DLMFS
+#include "cluster/masklog.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;
+
+
+
+/*
+ * 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
+ * POLLIN, 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.
+ *
+ * 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.
+ *
+ * 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:
+ * - bast : POLLIN against the file descriptor of a held lock
+ * signifies a bast fired on the lock.
+ */
+#define DLMFS_CAPABILITIES "bast stackglue"
+static int param_set_dlmfs_capabilities(const char *val,
+ struct kernel_param *kp)
+{
+ printk(KERN_ERR "%s: readonly parameter\n", kp->name);
+ return -EINVAL;
+}
+static int param_get_dlmfs_capabilities(char *buffer,
+ struct kernel_param *kp)
+{
+ return strlcpy(buffer, DLMFS_CAPABILITIES,
+ strlen(DLMFS_CAPABILITIES) + 1);
+}
+module_param_call(capabilities, param_set_dlmfs_capabilities,
+ param_get_dlmfs_capabilities, NULL, 0444);
+MODULE_PARM_DESC(capabilities, DLMFS_CAPABILITIES);
+
+
+/*
+ * 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 -> NOQUEUE
+ */
+static int dlmfs_decode_open_flags(int open_flags,
+ int *level,
+ int *flags)
+{
+ if (open_flags & (O_WRONLY|O_RDWR))
+ *level = DLM_LOCK_EX;
+ else
+ *level = DLM_LOCK_PR;
+
+ *flags = 0;
+ if (open_flags & O_NONBLOCK)
+ *flags |= DLM_LKF_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 & 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, status;
+ struct dlmfs_inode_private *ip = DLMFS_I(inode);
+ struct dlmfs_filp_private *fp = 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 != DLM_LOCK_IV)
+ user_dlm_cluster_unlock(&ip->ip_lockres, level);
+
+ kfree(fp);
+ file->private_data = NULL;
+ }
+
+ return 0;
+}
+
+/*
+ * We do ->setattr() just to override size changes. Our size is the size
+ * of the LVB and nothing else.
+ */
+static int dlmfs_file_setattr(struct dentry *dentry, struct iattr *attr)
+{
+ int error;
+ struct inode *inode = d_inode(dentry);
+
+ attr->ia_valid &= ~ATTR_SIZE;
+ error = inode_change_ok(inode, attr);
+ if (error)
+ return error;
+
+ setattr_copy(inode, attr);
+ mark_inode_dirty(inode);
+ return 0;
+}
+
+static unsigned int dlmfs_file_poll(struct file *file, poll_table *wait)
+{
+ int event = 0;
+ struct inode *inode = file_inode(file);
+ struct dlmfs_inode_private *ip = DLMFS_I(inode);
+
+ poll_wait(file, &ip->ip_lockres.l_event, wait);
+
+ spin_lock(&ip->ip_lockres.l_lock);
+ if (ip->ip_lockres.l_flags & USER_LOCK_BLOCKED)
+ event = POLLIN | POLLRDNORM;
+ spin_unlock(&ip->ip_lockres.l_lock);
+
+ return event;
+}
+
+static ssize_t dlmfs_file_read(struct file *filp,
+ char __user *buf,
+ size_t count,
+ loff_t *ppos)
+{
+ int bytes_left;
+ ssize_t readlen, got;
+ char *lvb_buf;
+ struct inode *inode = file_inode(filp);
+
+ 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;
+
+ lvb_buf = kmalloc(readlen, GFP_NOFS);
+ if (!lvb_buf)
+ return -ENOMEM;
+
+ got = user_dlm_read_lvb(inode, lvb_buf, readlen);
+ if (got) {
+ BUG_ON(got != readlen);
+ bytes_left = __copy_to_user(buf, lvb_buf, readlen);
+ readlen -= bytes_left;
+ } else
+ readlen = 0;
+
+ 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 = file_inode(filp);
+
+ 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(void *foo)
+{
+ struct dlmfs_inode_private *ip =
+ (struct dlmfs_inode_private *) foo;
+
+ ip->ip_conn = 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_i_callback(struct rcu_head *head)
+{
+ struct inode *inode = container_of(head, struct inode, i_rcu);
+ kmem_cache_free(dlmfs_inode_cache, DLMFS_I(inode));
+}
+
+static void dlmfs_destroy_inode(struct inode *inode)
+{
+ call_rcu(&inode->i_rcu, dlmfs_i_callback);
+}
+
+static void dlmfs_evict_inode(struct inode *inode)
+{
+ int status;
+ struct dlmfs_inode_private *ip;
+
+ clear_inode(inode);
+
+ 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_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;
+ 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;
+
+ 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;
+ 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;
+ 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_CACHE_SIZE;
+ sb->s_blocksize_bits = PAGE_CACHE_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,
+ .destroy_inode = dlmfs_destroy_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),
+ dlmfs_init_once);
+ if (!dlmfs_inode_cache) {
+ status = -ENOMEM;
+ goto bail;
+ }
+ cleanup_inode = 1;
+
+ user_dlm_worker = create_singlethread_workqueue("user_dlm");
+ 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);
+
+ flush_workqueue(user_dlm_worker);
+ 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_DESCRIPTION("OCFS2 DLM-Filesystem");
+
+module_init(init_dlmfs_fs)
+module_exit(exit_dlmfs_fs)
Code Review / kvmfornfv.git / blobdiff