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>
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>
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;
56 struct pstore_ftrace_seq_data {
62 #define REC_SIZE sizeof(struct pstore_ftrace_record)
64 static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
66 struct pstore_private *ps = s->private;
67 struct pstore_ftrace_seq_data *data;
69 data = kzalloc(sizeof(*data), GFP_KERNEL);
73 data->off = ps->size % REC_SIZE;
74 data->off += *pos * REC_SIZE;
75 if (data->off + REC_SIZE > ps->size) {
84 static void pstore_ftrace_seq_stop(struct seq_file *s, void *v)
89 static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos)
91 struct pstore_private *ps = s->private;
92 struct pstore_ftrace_seq_data *data = v;
94 data->off += REC_SIZE;
95 if (data->off + REC_SIZE > ps->size)
102 static int pstore_ftrace_seq_show(struct seq_file *s, void *v)
104 struct pstore_private *ps = s->private;
105 struct pstore_ftrace_seq_data *data = v;
106 struct pstore_ftrace_record *rec = (void *)(ps->data + data->off);
108 seq_printf(s, "%d %08lx %08lx %pf <- %pF\n",
109 pstore_ftrace_decode_cpu(rec), rec->ip, rec->parent_ip,
110 (void *)rec->ip, (void *)rec->parent_ip);
115 static const struct seq_operations pstore_ftrace_seq_ops = {
116 .start = pstore_ftrace_seq_start,
117 .next = pstore_ftrace_seq_next,
118 .stop = pstore_ftrace_seq_stop,
119 .show = pstore_ftrace_seq_show,
122 static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
123 size_t count, loff_t *ppos)
125 struct seq_file *sf = file->private_data;
126 struct pstore_private *ps = sf->private;
128 if (ps->type == PSTORE_TYPE_FTRACE)
129 return seq_read(file, userbuf, count, ppos);
130 return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
133 static int pstore_file_open(struct inode *inode, struct file *file)
135 struct pstore_private *ps = inode->i_private;
138 const struct seq_operations *sops = NULL;
140 if (ps->type == PSTORE_TYPE_FTRACE)
141 sops = &pstore_ftrace_seq_ops;
143 err = seq_open(file, sops);
147 sf = file->private_data;
153 static loff_t pstore_file_llseek(struct file *file, loff_t off, int origin)
155 struct seq_file *sf = file->private_data;
158 return seq_lseek(file, off, origin);
159 return default_llseek(file, off, origin);
162 static const struct file_operations pstore_file_operations = {
163 .open = pstore_file_open,
164 .read = pstore_file_read,
165 .llseek = pstore_file_llseek,
166 .release = seq_release,
170 * When a file is unlinked from our file system we call the
171 * platform driver to erase the record from persistent store.
173 static int pstore_unlink(struct inode *dir, struct dentry *dentry)
175 struct pstore_private *p = dentry->d_inode->i_private;
178 p->psi->erase(p->type, p->id, p->psi);
180 return simple_unlink(dir, dentry);
183 static void pstore_evict_inode(struct inode *inode)
185 struct pstore_private *p = inode->i_private;
190 spin_lock_irqsave(&allpstore_lock, flags);
192 spin_unlock_irqrestore(&allpstore_lock, flags);
197 static const struct inode_operations pstore_dir_inode_operations = {
198 .lookup = simple_lookup,
199 .unlink = pstore_unlink,
202 static struct inode *pstore_get_inode(struct super_block *sb)
204 struct inode *inode = new_inode(sb);
206 inode->i_ino = get_next_ino();
207 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
213 Opt_kmsg_bytes, Opt_err
216 static const match_table_t tokens = {
217 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
221 static void parse_options(char *options)
224 substring_t args[MAX_OPT_ARGS];
230 while ((p = strsep(&options, ",")) != NULL) {
236 token = match_token(p, tokens, args);
239 if (!match_int(&args[0], &option))
240 pstore_set_kmsg_bytes(option);
246 static int pstore_remount(struct super_block *sb, int *flags, char *data)
253 static const struct super_operations pstore_ops = {
254 .statfs = simple_statfs,
255 .drop_inode = generic_delete_inode,
256 .evict_inode = pstore_evict_inode,
257 .remount_fs = pstore_remount,
258 .show_options = generic_show_options,
261 static struct super_block *pstore_sb;
263 int pstore_is_mounted(void)
265 return pstore_sb != NULL;
269 * Make a regular file in the root directory of our file system.
270 * Load it up with "size" bytes of data from "buf".
271 * Set the mtime & ctime to the date that this record was originally stored.
273 int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
274 char *data, size_t size, struct timespec time,
275 struct pstore_info *psi)
277 struct dentry *root = pstore_sb->s_root;
278 struct dentry *dentry;
281 char name[PSTORE_NAMELEN];
282 struct pstore_private *private, *pos;
285 spin_lock_irqsave(&allpstore_lock, flags);
286 list_for_each_entry(pos, &allpstore, list) {
287 if (pos->type == type &&
294 spin_unlock_irqrestore(&allpstore_lock, flags);
299 inode = pstore_get_inode(pstore_sb);
302 inode->i_mode = S_IFREG | 0444;
303 inode->i_fop = &pstore_file_operations;
304 private = kmalloc(sizeof *private + size, GFP_KERNEL);
307 private->type = type;
312 case PSTORE_TYPE_DMESG:
313 sprintf(name, "dmesg-%s-%lld", psname, id);
315 case PSTORE_TYPE_CONSOLE:
316 sprintf(name, "console-%s", psname);
318 case PSTORE_TYPE_FTRACE:
319 sprintf(name, "ftrace-%s", psname);
321 case PSTORE_TYPE_MCE:
322 sprintf(name, "mce-%s-%lld", psname, id);
324 case PSTORE_TYPE_UNKNOWN:
325 sprintf(name, "unknown-%s-%lld", psname, id);
328 sprintf(name, "type%d-%s-%lld", type, psname, id);
332 mutex_lock(&root->d_inode->i_mutex);
335 dentry = d_alloc_name(root, name);
337 goto fail_lockedalloc;
339 memcpy(private->data, data, size);
340 inode->i_size = private->size = size;
342 inode->i_private = private;
345 inode->i_mtime = inode->i_ctime = time;
347 d_add(dentry, inode);
349 spin_lock_irqsave(&allpstore_lock, flags);
350 list_add(&private->list, &allpstore);
351 spin_unlock_irqrestore(&allpstore_lock, flags);
353 mutex_unlock(&root->d_inode->i_mutex);
358 mutex_unlock(&root->d_inode->i_mutex);
367 static int pstore_fill_super(struct super_block *sb, void *data, int silent)
371 save_mount_options(sb, data);
375 sb->s_maxbytes = MAX_LFS_FILESIZE;
376 sb->s_blocksize = PAGE_CACHE_SIZE;
377 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
378 sb->s_magic = PSTOREFS_MAGIC;
379 sb->s_op = &pstore_ops;
384 inode = pstore_get_inode(sb);
386 inode->i_mode = S_IFDIR | 0755;
387 inode->i_op = &pstore_dir_inode_operations;
388 inode->i_fop = &simple_dir_operations;
391 sb->s_root = d_make_root(inode);
395 pstore_get_records(0);
400 static struct dentry *pstore_mount(struct file_system_type *fs_type,
401 int flags, const char *dev_name, void *data)
403 return mount_single(fs_type, flags, data, pstore_fill_super);
406 static void pstore_kill_sb(struct super_block *sb)
408 kill_litter_super(sb);
412 static struct file_system_type pstore_fs_type = {
414 .mount = pstore_mount,
415 .kill_sb = pstore_kill_sb,
418 static int __init init_pstore_fs(void)
420 return register_filesystem(&pstore_fs_type);
422 module_init(init_pstore_fs)
424 MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
425 MODULE_LICENSE("GPL");