/* -*- 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)