ARM: 7747/1: pcpu: ensure __my_cpu_offset cannot be re-ordered across barrier()
[linux/fpc-iii.git] / fs / pstore / inode.c
blobe4bcb2cf055a1dc8f81df7cbb38e8cdab4add0b0
1 /*
2 * Persistent Storage - ramfs parts.
4 * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 #include <linux/module.h>
21 #include <linux/fs.h>
22 #include <linux/fsnotify.h>
23 #include <linux/pagemap.h>
24 #include <linux/highmem.h>
25 #include <linux/time.h>
26 #include <linux/init.h>
27 #include <linux/list.h>
28 #include <linux/string.h>
29 #include <linux/mount.h>
30 #include <linux/seq_file.h>
31 #include <linux/ramfs.h>
32 #include <linux/parser.h>
33 #include <linux/sched.h>
34 #include <linux/magic.h>
35 #include <linux/pstore.h>
36 #include <linux/slab.h>
37 #include <linux/spinlock.h>
38 #include <linux/uaccess.h>
40 #include "internal.h"
42 #define PSTORE_NAMELEN 64
44 static DEFINE_SPINLOCK(allpstore_lock);
45 static LIST_HEAD(allpstore);
47 struct pstore_private {
48 struct list_head list;
49 struct pstore_info *psi;
50 enum pstore_type_id type;
51 u64 id;
52 int count;
53 ssize_t size;
54 char data[];
57 struct pstore_ftrace_seq_data {
58 const void *ptr;
59 size_t off;
60 size_t size;
63 #define REC_SIZE sizeof(struct pstore_ftrace_record)
65 static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
67 struct pstore_private *ps = s->private;
68 struct pstore_ftrace_seq_data *data;
70 data = kzalloc(sizeof(*data), GFP_KERNEL);
71 if (!data)
72 return NULL;
74 data->off = ps->size % REC_SIZE;
75 data->off += *pos * REC_SIZE;
76 if (data->off + REC_SIZE > ps->size) {
77 kfree(data);
78 return NULL;
81 return data;
85 static void pstore_ftrace_seq_stop(struct seq_file *s, void *v)
87 kfree(v);
90 static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos)
92 struct pstore_private *ps = s->private;
93 struct pstore_ftrace_seq_data *data = v;
95 data->off += REC_SIZE;
96 if (data->off + REC_SIZE > ps->size)
97 return NULL;
99 (*pos)++;
100 return data;
103 static int pstore_ftrace_seq_show(struct seq_file *s, void *v)
105 struct pstore_private *ps = s->private;
106 struct pstore_ftrace_seq_data *data = v;
107 struct pstore_ftrace_record *rec = (void *)(ps->data + data->off);
109 seq_printf(s, "%d %08lx %08lx %pf <- %pF\n",
110 pstore_ftrace_decode_cpu(rec), rec->ip, rec->parent_ip,
111 (void *)rec->ip, (void *)rec->parent_ip);
113 return 0;
116 static const struct seq_operations pstore_ftrace_seq_ops = {
117 .start = pstore_ftrace_seq_start,
118 .next = pstore_ftrace_seq_next,
119 .stop = pstore_ftrace_seq_stop,
120 .show = pstore_ftrace_seq_show,
123 static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
124 size_t count, loff_t *ppos)
126 struct seq_file *sf = file->private_data;
127 struct pstore_private *ps = sf->private;
129 if (ps->type == PSTORE_TYPE_FTRACE)
130 return seq_read(file, userbuf, count, ppos);
131 return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
134 static int pstore_file_open(struct inode *inode, struct file *file)
136 struct pstore_private *ps = inode->i_private;
137 struct seq_file *sf;
138 int err;
139 const struct seq_operations *sops = NULL;
141 if (ps->type == PSTORE_TYPE_FTRACE)
142 sops = &pstore_ftrace_seq_ops;
144 err = seq_open(file, sops);
145 if (err < 0)
146 return err;
148 sf = file->private_data;
149 sf->private = ps;
151 return 0;
154 static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
156 struct seq_file *sf = file->private_data;
158 if (sf->op)
159 return seq_lseek(file, off, whence);
160 return default_llseek(file, off, whence);
163 static const struct file_operations pstore_file_operations = {
164 .open = pstore_file_open,
165 .read = pstore_file_read,
166 .llseek = pstore_file_llseek,
167 .release = seq_release,
171 * When a file is unlinked from our file system we call the
172 * platform driver to erase the record from persistent store.
174 static int pstore_unlink(struct inode *dir, struct dentry *dentry)
176 struct pstore_private *p = dentry->d_inode->i_private;
178 if (p->psi->erase)
179 p->psi->erase(p->type, p->id, p->count,
180 dentry->d_inode->i_ctime, p->psi);
182 return simple_unlink(dir, dentry);
185 static void pstore_evict_inode(struct inode *inode)
187 struct pstore_private *p = inode->i_private;
188 unsigned long flags;
190 clear_inode(inode);
191 if (p) {
192 spin_lock_irqsave(&allpstore_lock, flags);
193 list_del(&p->list);
194 spin_unlock_irqrestore(&allpstore_lock, flags);
195 kfree(p);
199 static const struct inode_operations pstore_dir_inode_operations = {
200 .lookup = simple_lookup,
201 .unlink = pstore_unlink,
204 static struct inode *pstore_get_inode(struct super_block *sb)
206 struct inode *inode = new_inode(sb);
207 if (inode) {
208 inode->i_ino = get_next_ino();
209 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
211 return inode;
214 enum {
215 Opt_kmsg_bytes, Opt_err
218 static const match_table_t tokens = {
219 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
220 {Opt_err, NULL}
223 static void parse_options(char *options)
225 char *p;
226 substring_t args[MAX_OPT_ARGS];
227 int option;
229 if (!options)
230 return;
232 while ((p = strsep(&options, ",")) != NULL) {
233 int token;
235 if (!*p)
236 continue;
238 token = match_token(p, tokens, args);
239 switch (token) {
240 case Opt_kmsg_bytes:
241 if (!match_int(&args[0], &option))
242 pstore_set_kmsg_bytes(option);
243 break;
248 static int pstore_remount(struct super_block *sb, int *flags, char *data)
250 parse_options(data);
252 return 0;
255 static const struct super_operations pstore_ops = {
256 .statfs = simple_statfs,
257 .drop_inode = generic_delete_inode,
258 .evict_inode = pstore_evict_inode,
259 .remount_fs = pstore_remount,
260 .show_options = generic_show_options,
263 static struct super_block *pstore_sb;
265 int pstore_is_mounted(void)
267 return pstore_sb != NULL;
271 * Make a regular file in the root directory of our file system.
272 * Load it up with "size" bytes of data from "buf".
273 * Set the mtime & ctime to the date that this record was originally stored.
275 int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
276 char *data, size_t size, struct timespec time,
277 struct pstore_info *psi)
279 struct dentry *root = pstore_sb->s_root;
280 struct dentry *dentry;
281 struct inode *inode;
282 int rc = 0;
283 char name[PSTORE_NAMELEN];
284 struct pstore_private *private, *pos;
285 unsigned long flags;
287 spin_lock_irqsave(&allpstore_lock, flags);
288 list_for_each_entry(pos, &allpstore, list) {
289 if (pos->type == type &&
290 pos->id == id &&
291 pos->psi == psi) {
292 rc = -EEXIST;
293 break;
296 spin_unlock_irqrestore(&allpstore_lock, flags);
297 if (rc)
298 return rc;
300 rc = -ENOMEM;
301 inode = pstore_get_inode(pstore_sb);
302 if (!inode)
303 goto fail;
304 inode->i_mode = S_IFREG | 0444;
305 inode->i_fop = &pstore_file_operations;
306 private = kmalloc(sizeof *private + size, GFP_KERNEL);
307 if (!private)
308 goto fail_alloc;
309 private->type = type;
310 private->id = id;
311 private->count = count;
312 private->psi = psi;
314 switch (type) {
315 case PSTORE_TYPE_DMESG:
316 sprintf(name, "dmesg-%s-%lld", psname, id);
317 break;
318 case PSTORE_TYPE_CONSOLE:
319 sprintf(name, "console-%s", psname);
320 break;
321 case PSTORE_TYPE_FTRACE:
322 sprintf(name, "ftrace-%s", psname);
323 break;
324 case PSTORE_TYPE_MCE:
325 sprintf(name, "mce-%s-%lld", psname, id);
326 break;
327 case PSTORE_TYPE_UNKNOWN:
328 sprintf(name, "unknown-%s-%lld", psname, id);
329 break;
330 default:
331 sprintf(name, "type%d-%s-%lld", type, psname, id);
332 break;
335 mutex_lock(&root->d_inode->i_mutex);
337 rc = -ENOSPC;
338 dentry = d_alloc_name(root, name);
339 if (IS_ERR(dentry))
340 goto fail_lockedalloc;
342 memcpy(private->data, data, size);
343 inode->i_size = private->size = size;
345 inode->i_private = private;
347 if (time.tv_sec)
348 inode->i_mtime = inode->i_ctime = time;
350 d_add(dentry, inode);
352 spin_lock_irqsave(&allpstore_lock, flags);
353 list_add(&private->list, &allpstore);
354 spin_unlock_irqrestore(&allpstore_lock, flags);
356 mutex_unlock(&root->d_inode->i_mutex);
358 return 0;
360 fail_lockedalloc:
361 mutex_unlock(&root->d_inode->i_mutex);
362 kfree(private);
363 fail_alloc:
364 iput(inode);
366 fail:
367 return rc;
370 static int pstore_fill_super(struct super_block *sb, void *data, int silent)
372 struct inode *inode;
374 save_mount_options(sb, data);
376 pstore_sb = sb;
378 sb->s_maxbytes = MAX_LFS_FILESIZE;
379 sb->s_blocksize = PAGE_CACHE_SIZE;
380 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
381 sb->s_magic = PSTOREFS_MAGIC;
382 sb->s_op = &pstore_ops;
383 sb->s_time_gran = 1;
385 parse_options(data);
387 inode = pstore_get_inode(sb);
388 if (inode) {
389 inode->i_mode = S_IFDIR | 0755;
390 inode->i_op = &pstore_dir_inode_operations;
391 inode->i_fop = &simple_dir_operations;
392 inc_nlink(inode);
394 sb->s_root = d_make_root(inode);
395 if (!sb->s_root)
396 return -ENOMEM;
398 pstore_get_records(0);
400 return 0;
403 static struct dentry *pstore_mount(struct file_system_type *fs_type,
404 int flags, const char *dev_name, void *data)
406 return mount_single(fs_type, flags, data, pstore_fill_super);
409 static void pstore_kill_sb(struct super_block *sb)
411 kill_litter_super(sb);
412 pstore_sb = NULL;
415 static struct file_system_type pstore_fs_type = {
416 .name = "pstore",
417 .mount = pstore_mount,
418 .kill_sb = pstore_kill_sb,
421 static struct kobject *pstore_kobj;
423 static int __init init_pstore_fs(void)
425 int err = 0;
427 /* Create a convenient mount point for people to access pstore */
428 pstore_kobj = kobject_create_and_add("pstore", fs_kobj);
429 if (!pstore_kobj) {
430 err = -ENOMEM;
431 goto out;
434 err = register_filesystem(&pstore_fs_type);
435 if (err < 0)
436 kobject_put(pstore_kobj);
438 out:
439 return err;
441 module_init(init_pstore_fs)
443 MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
444 MODULE_LICENSE("GPL");