diff options
author | Mark Fasheh <mark.fasheh@oracle.com> | 2005-12-15 22:31:23 (GMT) |
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committer | Joel Becker <joel.becker@oracle.com> | 2006-01-03 19:45:47 (GMT) |
commit | 8df08c89c668e1bd922a053fdb5ba1fadbecbb38 (patch) | |
tree | ab1febb732c01a66c0a9bfe9c8952ba2bb66fba8 /fs/ocfs2/dlm/dlmfs.c | |
parent | 6714d8e86bf443f6f7af50f9d432025649f091f5 (diff) | |
download | linux-fsl-qoriq-8df08c89c668e1bd922a053fdb5ba1fadbecbb38.tar.xz |
[PATCH] OCFS2: The Second Oracle Cluster Filesystem
dlmfs: A minimal dlm userspace interface implemented via a virtual
file system.
Most of the OCFS2 tools make use of this to take cluster locks when
doing operations on the file system.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Signed-off-by: Kurt Hackel <kurt.hackel@oracle.com>
Diffstat (limited to 'fs/ocfs2/dlm/dlmfs.c')
-rw-r--r-- | fs/ocfs2/dlm/dlmfs.c | 640 |
1 files changed, 640 insertions, 0 deletions
diff --git a/fs/ocfs2/dlm/dlmfs.c b/fs/ocfs2/dlm/dlmfs.c new file mode 100644 index 0000000..dd2d24d --- /dev/null +++ b/fs/ocfs2/dlm/dlmfs.c @@ -0,0 +1,640 @@ +/* -*- 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/smp_lock.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" + +static struct super_operations dlmfs_ops; +static struct file_operations dlmfs_file_operations; +static struct inode_operations dlmfs_dir_inode_operations; +static struct inode_operations dlmfs_root_inode_operations; +static struct inode_operations dlmfs_file_inode_operations; +static kmem_cache_t *dlmfs_inode_cache; + +struct workqueue_struct *user_dlm_worker; + +/* + * 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_KERNEL); + 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_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_KERNEL); + 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_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_KERNEL); + 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, + kmem_cache_t *cachep, + unsigned long flags) +{ + struct dlmfs_inode_private *ip = + (struct dlmfs_inode_private *) foo; + + if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == + SLAB_CTOR_CONSTRUCTOR) { + 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, SLAB_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_blksize = PAGE_CACHE_SIZE; + 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; + inode->i_nlink++; + + 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_blksize = PAGE_CACHE_SIZE; + 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) */ + inode->i_nlink++; + 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; + + 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); + 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; + + dir->i_nlink++; + 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 struct file_operations dlmfs_file_operations = { + .open = dlmfs_file_open, + .release = dlmfs_file_release, + .read = dlmfs_file_read, + .write = dlmfs_file_write, +}; + +static 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 struct inode_operations dlmfs_root_inode_operations = { + .lookup = simple_lookup, + .mkdir = dlmfs_mkdir, + .rmdir = simple_rmdir, +}; + +static 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 struct inode_operations dlmfs_file_inode_operations = { + .getattr = simple_getattr, +}; + +static struct super_block *dlmfs_get_sb(struct file_system_type *fs_type, + int flags, const char *dev_name, void *data) +{ + return get_sb_nodev(fs_type, flags, data, dlmfs_fill_super); +} + +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(); + + dlmfs_inode_cache = kmem_cache_create("dlmfs_inode_cache", + sizeof(struct dlmfs_inode_private), + 0, SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT, + dlmfs_init_once, NULL); + if (!dlmfs_inode_cache) + return -ENOMEM; + 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); + } 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); + + if (kmem_cache_destroy(dlmfs_inode_cache)) + printk(KERN_INFO "dlmfs_inode_cache: not all structures " + "were freed\n"); +} + +MODULE_AUTHOR("Oracle"); +MODULE_LICENSE("GPL"); + +module_init(init_dlmfs_fs) +module_exit(exit_dlmfs_fs) |