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TOMOYO Linux Cross Reference
Linux/fs/pstore/inode.c

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  1 /*
  2  * Persistent Storage - ramfs parts.
  3  *
  4  * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
  5  *
  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.
  9  *
 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.
 14  *
 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
 18  */
 19 
 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>
 39 
 40 #include "internal.h"
 41 
 42 #define PSTORE_NAMELEN  64
 43 
 44 static DEFINE_SPINLOCK(allpstore_lock);
 45 static LIST_HEAD(allpstore);
 46 
 47 struct pstore_private {
 48         struct list_head list;
 49         struct pstore_record *record;
 50         size_t total_size;
 51 };
 52 
 53 struct pstore_ftrace_seq_data {
 54         const void *ptr;
 55         size_t off;
 56         size_t size;
 57 };
 58 
 59 #define REC_SIZE sizeof(struct pstore_ftrace_record)
 60 
 61 static void free_pstore_private(struct pstore_private *private)
 62 {
 63         if (!private)
 64                 return;
 65         if (private->record) {
 66                 kfree(private->record->buf);
 67                 kfree(private->record);
 68         }
 69         kfree(private);
 70 }
 71 
 72 static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
 73 {
 74         struct pstore_private *ps = s->private;
 75         struct pstore_ftrace_seq_data *data;
 76 
 77         data = kzalloc(sizeof(*data), GFP_KERNEL);
 78         if (!data)
 79                 return NULL;
 80 
 81         data->off = ps->total_size % REC_SIZE;
 82         data->off += *pos * REC_SIZE;
 83         if (data->off + REC_SIZE > ps->total_size) {
 84                 kfree(data);
 85                 return NULL;
 86         }
 87 
 88         return data;
 89 
 90 }
 91 
 92 static void pstore_ftrace_seq_stop(struct seq_file *s, void *v)
 93 {
 94         kfree(v);
 95 }
 96 
 97 static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos)
 98 {
 99         struct pstore_private *ps = s->private;
100         struct pstore_ftrace_seq_data *data = v;
101 
102         data->off += REC_SIZE;
103         if (data->off + REC_SIZE > ps->total_size)
104                 return NULL;
105 
106         (*pos)++;
107         return data;
108 }
109 
110 static int pstore_ftrace_seq_show(struct seq_file *s, void *v)
111 {
112         struct pstore_private *ps = s->private;
113         struct pstore_ftrace_seq_data *data = v;
114         struct pstore_ftrace_record *rec;
115 
116         rec = (struct pstore_ftrace_record *)(ps->record->buf + data->off);
117 
118         seq_printf(s, "CPU:%d ts:%llu %08lx  %08lx  %pf <- %pF\n",
119                    pstore_ftrace_decode_cpu(rec),
120                    pstore_ftrace_read_timestamp(rec),
121                    rec->ip, rec->parent_ip, (void *)rec->ip,
122                    (void *)rec->parent_ip);
123 
124         return 0;
125 }
126 
127 static const struct seq_operations pstore_ftrace_seq_ops = {
128         .start  = pstore_ftrace_seq_start,
129         .next   = pstore_ftrace_seq_next,
130         .stop   = pstore_ftrace_seq_stop,
131         .show   = pstore_ftrace_seq_show,
132 };
133 
134 static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
135                                                 size_t count, loff_t *ppos)
136 {
137         struct seq_file *sf = file->private_data;
138         struct pstore_private *ps = sf->private;
139 
140         if (ps->record->type == PSTORE_TYPE_FTRACE)
141                 return seq_read(file, userbuf, count, ppos);
142         return simple_read_from_buffer(userbuf, count, ppos,
143                                        ps->record->buf, ps->total_size);
144 }
145 
146 static int pstore_file_open(struct inode *inode, struct file *file)
147 {
148         struct pstore_private *ps = inode->i_private;
149         struct seq_file *sf;
150         int err;
151         const struct seq_operations *sops = NULL;
152 
153         if (ps->record->type == PSTORE_TYPE_FTRACE)
154                 sops = &pstore_ftrace_seq_ops;
155 
156         err = seq_open(file, sops);
157         if (err < 0)
158                 return err;
159 
160         sf = file->private_data;
161         sf->private = ps;
162 
163         return 0;
164 }
165 
166 static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
167 {
168         struct seq_file *sf = file->private_data;
169 
170         if (sf->op)
171                 return seq_lseek(file, off, whence);
172         return default_llseek(file, off, whence);
173 }
174 
175 static const struct file_operations pstore_file_operations = {
176         .open           = pstore_file_open,
177         .read           = pstore_file_read,
178         .llseek         = pstore_file_llseek,
179         .release        = seq_release,
180 };
181 
182 /*
183  * When a file is unlinked from our file system we call the
184  * platform driver to erase the record from persistent store.
185  */
186 static int pstore_unlink(struct inode *dir, struct dentry *dentry)
187 {
188         struct pstore_private *p = d_inode(dentry)->i_private;
189         struct pstore_record *record = p->record;
190 
191         if (!record->psi->erase)
192                 return -EPERM;
193 
194         mutex_lock(&record->psi->read_mutex);
195         record->psi->erase(record);
196         mutex_unlock(&record->psi->read_mutex);
197 
198         return simple_unlink(dir, dentry);
199 }
200 
201 static void pstore_evict_inode(struct inode *inode)
202 {
203         struct pstore_private   *p = inode->i_private;
204         unsigned long           flags;
205 
206         clear_inode(inode);
207         if (p) {
208                 spin_lock_irqsave(&allpstore_lock, flags);
209                 list_del(&p->list);
210                 spin_unlock_irqrestore(&allpstore_lock, flags);
211                 free_pstore_private(p);
212         }
213 }
214 
215 static const struct inode_operations pstore_dir_inode_operations = {
216         .lookup         = simple_lookup,
217         .unlink         = pstore_unlink,
218 };
219 
220 static struct inode *pstore_get_inode(struct super_block *sb)
221 {
222         struct inode *inode = new_inode(sb);
223         if (inode) {
224                 inode->i_ino = get_next_ino();
225                 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
226         }
227         return inode;
228 }
229 
230 enum {
231         Opt_kmsg_bytes, Opt_err
232 };
233 
234 static const match_table_t tokens = {
235         {Opt_kmsg_bytes, "kmsg_bytes=%u"},
236         {Opt_err, NULL}
237 };
238 
239 static void parse_options(char *options)
240 {
241         char            *p;
242         substring_t     args[MAX_OPT_ARGS];
243         int             option;
244 
245         if (!options)
246                 return;
247 
248         while ((p = strsep(&options, ",")) != NULL) {
249                 int token;
250 
251                 if (!*p)
252                         continue;
253 
254                 token = match_token(p, tokens, args);
255                 switch (token) {
256                 case Opt_kmsg_bytes:
257                         if (!match_int(&args[0], &option))
258                                 pstore_set_kmsg_bytes(option);
259                         break;
260                 }
261         }
262 }
263 
264 /*
265  * Display the mount options in /proc/mounts.
266  */
267 static int pstore_show_options(struct seq_file *m, struct dentry *root)
268 {
269         if (kmsg_bytes != PSTORE_DEFAULT_KMSG_BYTES)
270                 seq_printf(m, ",kmsg_bytes=%lu", kmsg_bytes);
271         return 0;
272 }
273 
274 static int pstore_remount(struct super_block *sb, int *flags, char *data)
275 {
276         sync_filesystem(sb);
277         parse_options(data);
278 
279         return 0;
280 }
281 
282 static const struct super_operations pstore_ops = {
283         .statfs         = simple_statfs,
284         .drop_inode     = generic_delete_inode,
285         .evict_inode    = pstore_evict_inode,
286         .remount_fs     = pstore_remount,
287         .show_options   = pstore_show_options,
288 };
289 
290 static struct super_block *pstore_sb;
291 
292 bool pstore_is_mounted(void)
293 {
294         return pstore_sb != NULL;
295 }
296 
297 /*
298  * Make a regular file in the root directory of our file system.
299  * Load it up with "size" bytes of data from "buf".
300  * Set the mtime & ctime to the date that this record was originally stored.
301  */
302 int pstore_mkfile(struct dentry *root, struct pstore_record *record)
303 {
304         struct dentry           *dentry;
305         struct inode            *inode;
306         int                     rc = 0;
307         char                    name[PSTORE_NAMELEN];
308         struct pstore_private   *private, *pos;
309         unsigned long           flags;
310         size_t                  size = record->size + record->ecc_notice_size;
311 
312         WARN_ON(!inode_is_locked(d_inode(root)));
313 
314         spin_lock_irqsave(&allpstore_lock, flags);
315         list_for_each_entry(pos, &allpstore, list) {
316                 if (pos->record->type == record->type &&
317                     pos->record->id == record->id &&
318                     pos->record->psi == record->psi) {
319                         rc = -EEXIST;
320                         break;
321                 }
322         }
323         spin_unlock_irqrestore(&allpstore_lock, flags);
324         if (rc)
325                 return rc;
326 
327         rc = -ENOMEM;
328         inode = pstore_get_inode(root->d_sb);
329         if (!inode)
330                 goto fail;
331         inode->i_mode = S_IFREG | 0444;
332         inode->i_fop = &pstore_file_operations;
333         private = kzalloc(sizeof(*private), GFP_KERNEL);
334         if (!private)
335                 goto fail_alloc;
336         private->record = record;
337 
338         switch (record->type) {
339         case PSTORE_TYPE_DMESG:
340                 scnprintf(name, sizeof(name), "dmesg-%s-%llu%s",
341                           record->psi->name, record->id,
342                           record->compressed ? ".enc.z" : "");
343                 break;
344         case PSTORE_TYPE_CONSOLE:
345                 scnprintf(name, sizeof(name), "console-%s-%llu",
346                           record->psi->name, record->id);
347                 break;
348         case PSTORE_TYPE_FTRACE:
349                 scnprintf(name, sizeof(name), "ftrace-%s-%llu",
350                           record->psi->name, record->id);
351                 break;
352         case PSTORE_TYPE_MCE:
353                 scnprintf(name, sizeof(name), "mce-%s-%llu",
354                           record->psi->name, record->id);
355                 break;
356         case PSTORE_TYPE_PPC_RTAS:
357                 scnprintf(name, sizeof(name), "rtas-%s-%llu",
358                           record->psi->name, record->id);
359                 break;
360         case PSTORE_TYPE_PPC_OF:
361                 scnprintf(name, sizeof(name), "powerpc-ofw-%s-%llu",
362                           record->psi->name, record->id);
363                 break;
364         case PSTORE_TYPE_PPC_COMMON:
365                 scnprintf(name, sizeof(name), "powerpc-common-%s-%llu",
366                           record->psi->name, record->id);
367                 break;
368         case PSTORE_TYPE_PMSG:
369                 scnprintf(name, sizeof(name), "pmsg-%s-%llu",
370                           record->psi->name, record->id);
371                 break;
372         case PSTORE_TYPE_PPC_OPAL:
373                 scnprintf(name, sizeof(name), "powerpc-opal-%s-%llu",
374                           record->psi->name, record->id);
375                 break;
376         case PSTORE_TYPE_UNKNOWN:
377                 scnprintf(name, sizeof(name), "unknown-%s-%llu",
378                           record->psi->name, record->id);
379                 break;
380         default:
381                 scnprintf(name, sizeof(name), "type%d-%s-%llu",
382                           record->type, record->psi->name, record->id);
383                 break;
384         }
385 
386         dentry = d_alloc_name(root, name);
387         if (!dentry)
388                 goto fail_private;
389 
390         inode->i_size = private->total_size = size;
391 
392         inode->i_private = private;
393 
394         if (record->time.tv_sec)
395                 inode->i_mtime = inode->i_ctime = record->time;
396 
397         d_add(dentry, inode);
398 
399         spin_lock_irqsave(&allpstore_lock, flags);
400         list_add(&private->list, &allpstore);
401         spin_unlock_irqrestore(&allpstore_lock, flags);
402 
403         return 0;
404 
405 fail_private:
406         free_pstore_private(private);
407 fail_alloc:
408         iput(inode);
409 
410 fail:
411         return rc;
412 }
413 
414 /*
415  * Read all the records from the persistent store. Create
416  * files in our filesystem.  Don't warn about -EEXIST errors
417  * when we are re-scanning the backing store looking to add new
418  * error records.
419  */
420 void pstore_get_records(int quiet)
421 {
422         struct pstore_info *psi = psinfo;
423         struct dentry *root;
424 
425         if (!psi || !pstore_sb)
426                 return;
427 
428         root = pstore_sb->s_root;
429 
430         inode_lock(d_inode(root));
431         pstore_get_backend_records(psi, root, quiet);
432         inode_unlock(d_inode(root));
433 }
434 
435 static int pstore_fill_super(struct super_block *sb, void *data, int silent)
436 {
437         struct inode *inode;
438 
439         pstore_sb = sb;
440 
441         sb->s_maxbytes          = MAX_LFS_FILESIZE;
442         sb->s_blocksize         = PAGE_SIZE;
443         sb->s_blocksize_bits    = PAGE_SHIFT;
444         sb->s_magic             = PSTOREFS_MAGIC;
445         sb->s_op                = &pstore_ops;
446         sb->s_time_gran         = 1;
447 
448         parse_options(data);
449 
450         inode = pstore_get_inode(sb);
451         if (inode) {
452                 inode->i_mode = S_IFDIR | 0750;
453                 inode->i_op = &pstore_dir_inode_operations;
454                 inode->i_fop = &simple_dir_operations;
455                 inc_nlink(inode);
456         }
457         sb->s_root = d_make_root(inode);
458         if (!sb->s_root)
459                 return -ENOMEM;
460 
461         pstore_get_records(0);
462 
463         return 0;
464 }
465 
466 static struct dentry *pstore_mount(struct file_system_type *fs_type,
467         int flags, const char *dev_name, void *data)
468 {
469         return mount_single(fs_type, flags, data, pstore_fill_super);
470 }
471 
472 static void pstore_kill_sb(struct super_block *sb)
473 {
474         kill_litter_super(sb);
475         pstore_sb = NULL;
476 }
477 
478 static struct file_system_type pstore_fs_type = {
479         .owner          = THIS_MODULE,
480         .name           = "pstore",
481         .mount          = pstore_mount,
482         .kill_sb        = pstore_kill_sb,
483 };
484 
485 static int __init init_pstore_fs(void)
486 {
487         int err;
488 
489         pstore_choose_compression();
490 
491         /* Create a convenient mount point for people to access pstore */
492         err = sysfs_create_mount_point(fs_kobj, "pstore");
493         if (err)
494                 goto out;
495 
496         err = register_filesystem(&pstore_fs_type);
497         if (err < 0)
498                 sysfs_remove_mount_point(fs_kobj, "pstore");
499 
500 out:
501         return err;
502 }
503 module_init(init_pstore_fs)
504 
505 static void __exit exit_pstore_fs(void)
506 {
507         unregister_filesystem(&pstore_fs_type);
508         sysfs_remove_mount_point(fs_kobj, "pstore");
509 }
510 module_exit(exit_pstore_fs)
511 
512 MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
513 MODULE_LICENSE("GPL");
514 

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