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