457 lines
10 KiB
C
457 lines
10 KiB
C
/*
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* Persistent Storage - ramfs parts.
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*
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* Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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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/fsnotify.h>
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#include <linux/pagemap.h>
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#include <linux/highmem.h>
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#include <linux/time.h>
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#include <linux/init.h>
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#include <linux/list.h>
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#include <linux/string.h>
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#include <linux/mount.h>
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#include <linux/seq_file.h>
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#include <linux/ramfs.h>
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#include <linux/parser.h>
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#include <linux/sched.h>
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#include <linux/magic.h>
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#include <linux/pstore.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/uaccess.h>
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#include "internal.h"
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#define PSTORE_NAMELEN 64
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static DEFINE_SPINLOCK(allpstore_lock);
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static LIST_HEAD(allpstore);
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struct pstore_private {
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struct list_head list;
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struct pstore_info *psi;
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enum pstore_type_id type;
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u64 id;
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int count;
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ssize_t size;
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char data[];
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};
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struct pstore_ftrace_seq_data {
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const void *ptr;
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size_t off;
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size_t size;
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};
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#define REC_SIZE sizeof(struct pstore_ftrace_record)
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static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
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{
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struct pstore_private *ps = s->private;
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struct pstore_ftrace_seq_data *data;
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data = kzalloc(sizeof(*data), GFP_KERNEL);
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if (!data)
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return NULL;
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data->off = ps->size % REC_SIZE;
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data->off += *pos * REC_SIZE;
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if (data->off + REC_SIZE > ps->size) {
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kfree(data);
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return NULL;
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}
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return data;
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}
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static void pstore_ftrace_seq_stop(struct seq_file *s, void *v)
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{
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kfree(v);
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}
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static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos)
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{
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struct pstore_private *ps = s->private;
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struct pstore_ftrace_seq_data *data = v;
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data->off += REC_SIZE;
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if (data->off + REC_SIZE > ps->size)
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return NULL;
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(*pos)++;
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return data;
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}
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static int pstore_ftrace_seq_show(struct seq_file *s, void *v)
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{
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struct pstore_private *ps = s->private;
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struct pstore_ftrace_seq_data *data = v;
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struct pstore_ftrace_record *rec = (void *)(ps->data + data->off);
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seq_printf(s, "%d %08lx %08lx %pf <- %pF\n",
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pstore_ftrace_decode_cpu(rec), rec->ip, rec->parent_ip,
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(void *)rec->ip, (void *)rec->parent_ip);
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return 0;
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}
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static const struct seq_operations pstore_ftrace_seq_ops = {
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.start = pstore_ftrace_seq_start,
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.next = pstore_ftrace_seq_next,
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.stop = pstore_ftrace_seq_stop,
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.show = pstore_ftrace_seq_show,
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};
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static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
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size_t count, loff_t *ppos)
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{
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struct seq_file *sf = file->private_data;
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struct pstore_private *ps = sf->private;
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if (ps->type == PSTORE_TYPE_FTRACE)
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return seq_read(file, userbuf, count, ppos);
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return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
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}
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static int pstore_file_open(struct inode *inode, struct file *file)
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{
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struct pstore_private *ps = inode->i_private;
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struct seq_file *sf;
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int err;
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const struct seq_operations *sops = NULL;
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if (ps->type == PSTORE_TYPE_FTRACE)
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sops = &pstore_ftrace_seq_ops;
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err = seq_open(file, sops);
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if (err < 0)
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return err;
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sf = file->private_data;
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sf->private = ps;
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return 0;
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}
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static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
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{
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struct seq_file *sf = file->private_data;
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if (sf->op)
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return seq_lseek(file, off, whence);
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return default_llseek(file, off, whence);
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}
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static const struct file_operations pstore_file_operations = {
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.open = pstore_file_open,
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.read = pstore_file_read,
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.llseek = pstore_file_llseek,
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.release = seq_release,
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};
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/*
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* When a file is unlinked from our file system we call the
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* platform driver to erase the record from persistent store.
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*/
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static int pstore_unlink(struct inode *dir, struct dentry *dentry)
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{
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struct pstore_private *p = dentry->d_inode->i_private;
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if (p->psi->erase)
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p->psi->erase(p->type, p->id, p->count,
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dentry->d_inode->i_ctime, p->psi);
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else
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return -EPERM;
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return simple_unlink(dir, dentry);
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}
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static void pstore_evict_inode(struct inode *inode)
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{
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struct pstore_private *p = inode->i_private;
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unsigned long flags;
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clear_inode(inode);
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if (p) {
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spin_lock_irqsave(&allpstore_lock, flags);
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list_del(&p->list);
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spin_unlock_irqrestore(&allpstore_lock, flags);
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kfree(p);
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}
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}
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static const struct inode_operations pstore_dir_inode_operations = {
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.lookup = simple_lookup,
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.unlink = pstore_unlink,
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};
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static struct inode *pstore_get_inode(struct super_block *sb)
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{
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struct inode *inode = new_inode(sb);
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if (inode) {
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inode->i_ino = get_next_ino();
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inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
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}
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return inode;
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}
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enum {
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Opt_kmsg_bytes, Opt_err
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};
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static const match_table_t tokens = {
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{Opt_kmsg_bytes, "kmsg_bytes=%u"},
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{Opt_err, NULL}
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};
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static void parse_options(char *options)
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{
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char *p;
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substring_t args[MAX_OPT_ARGS];
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int option;
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if (!options)
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return;
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while ((p = strsep(&options, ",")) != NULL) {
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int token;
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if (!*p)
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continue;
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token = match_token(p, tokens, args);
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switch (token) {
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case Opt_kmsg_bytes:
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if (!match_int(&args[0], &option))
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pstore_set_kmsg_bytes(option);
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break;
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}
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}
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}
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static int pstore_remount(struct super_block *sb, int *flags, char *data)
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{
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sync_filesystem(sb);
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parse_options(data);
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return 0;
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}
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static const struct super_operations pstore_ops = {
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.statfs = simple_statfs,
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.drop_inode = generic_delete_inode,
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.evict_inode = pstore_evict_inode,
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.remount_fs = pstore_remount,
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.show_options = generic_show_options,
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};
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static struct super_block *pstore_sb;
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int pstore_is_mounted(void)
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{
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return pstore_sb != NULL;
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}
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/*
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* Make a regular file in the root directory of our file system.
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* Load it up with "size" bytes of data from "buf".
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* Set the mtime & ctime to the date that this record was originally stored.
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*/
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int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
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char *data, bool compressed, size_t size,
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struct timespec time, struct pstore_info *psi)
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{
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struct dentry *root = pstore_sb->s_root;
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struct dentry *dentry;
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struct inode *inode;
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int rc = 0;
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char name[PSTORE_NAMELEN];
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struct pstore_private *private, *pos;
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unsigned long flags;
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spin_lock_irqsave(&allpstore_lock, flags);
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list_for_each_entry(pos, &allpstore, list) {
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if (pos->type == type &&
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pos->id == id &&
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pos->psi == psi) {
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rc = -EEXIST;
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break;
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}
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}
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spin_unlock_irqrestore(&allpstore_lock, flags);
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if (rc)
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return rc;
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rc = -ENOMEM;
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inode = pstore_get_inode(pstore_sb);
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if (!inode)
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goto fail;
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inode->i_mode = S_IFREG | 0444;
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inode->i_fop = &pstore_file_operations;
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private = kmalloc(sizeof *private + size, GFP_KERNEL);
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if (!private)
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goto fail_alloc;
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private->type = type;
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private->id = id;
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private->count = count;
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private->psi = psi;
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switch (type) {
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case PSTORE_TYPE_DMESG:
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sprintf(name, "dmesg-%s-%lld%s", psname, id,
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compressed ? ".enc.z" : "");
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break;
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case PSTORE_TYPE_CONSOLE:
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sprintf(name, "console-%s-%lld", psname, id);
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break;
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case PSTORE_TYPE_FTRACE:
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sprintf(name, "ftrace-%s-%lld", psname, id);
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break;
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case PSTORE_TYPE_MCE:
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sprintf(name, "mce-%s-%lld", psname, id);
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break;
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case PSTORE_TYPE_PPC_RTAS:
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sprintf(name, "rtas-%s-%lld", psname, id);
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break;
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case PSTORE_TYPE_PPC_OF:
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sprintf(name, "powerpc-ofw-%s-%lld", psname, id);
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break;
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case PSTORE_TYPE_PPC_COMMON:
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sprintf(name, "powerpc-common-%s-%lld", psname, id);
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break;
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case PSTORE_TYPE_UNKNOWN:
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sprintf(name, "unknown-%s-%lld", psname, id);
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break;
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default:
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sprintf(name, "type%d-%s-%lld", type, psname, id);
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break;
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}
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mutex_lock(&root->d_inode->i_mutex);
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dentry = d_alloc_name(root, name);
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if (!dentry)
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goto fail_lockedalloc;
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memcpy(private->data, data, size);
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inode->i_size = private->size = size;
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inode->i_private = private;
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if (time.tv_sec)
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inode->i_mtime = inode->i_ctime = time;
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d_add(dentry, inode);
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spin_lock_irqsave(&allpstore_lock, flags);
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list_add(&private->list, &allpstore);
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spin_unlock_irqrestore(&allpstore_lock, flags);
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mutex_unlock(&root->d_inode->i_mutex);
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return 0;
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fail_lockedalloc:
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mutex_unlock(&root->d_inode->i_mutex);
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kfree(private);
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fail_alloc:
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iput(inode);
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fail:
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return rc;
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}
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static int pstore_fill_super(struct super_block *sb, void *data, int silent)
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{
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struct inode *inode;
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save_mount_options(sb, data);
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pstore_sb = sb;
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sb->s_maxbytes = MAX_LFS_FILESIZE;
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sb->s_blocksize = PAGE_CACHE_SIZE;
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sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
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sb->s_magic = PSTOREFS_MAGIC;
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sb->s_op = &pstore_ops;
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sb->s_time_gran = 1;
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parse_options(data);
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inode = pstore_get_inode(sb);
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if (inode) {
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inode->i_mode = S_IFDIR | 0755;
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inode->i_op = &pstore_dir_inode_operations;
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inode->i_fop = &simple_dir_operations;
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inc_nlink(inode);
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}
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sb->s_root = d_make_root(inode);
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if (!sb->s_root)
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return -ENOMEM;
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pstore_get_records(0);
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return 0;
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}
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static struct dentry *pstore_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_single(fs_type, flags, data, pstore_fill_super);
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}
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static void pstore_kill_sb(struct super_block *sb)
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{
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kill_litter_super(sb);
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pstore_sb = NULL;
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}
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static struct file_system_type pstore_fs_type = {
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.name = "pstore",
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.mount = pstore_mount,
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.kill_sb = pstore_kill_sb,
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};
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static struct kobject *pstore_kobj;
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static int __init init_pstore_fs(void)
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{
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int err = 0;
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/* Create a convenient mount point for people to access pstore */
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pstore_kobj = kobject_create_and_add("pstore", fs_kobj);
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if (!pstore_kobj) {
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err = -ENOMEM;
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goto out;
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}
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err = register_filesystem(&pstore_fs_type);
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if (err < 0)
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kobject_put(pstore_kobj);
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out:
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return err;
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}
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module_init(init_pstore_fs)
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MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
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MODULE_LICENSE("GPL");
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