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/ramfs.h>
31 #include <linux/parser.h>
32 #include <linux/sched.h>
33 #include <linux/magic.h>
34 #include <linux/pstore.h>
35 #include <linux/slab.h>
36 #include <linux/spinlock.h>
37 #include <linux/uaccess.h>
41 #define PSTORE_NAMELEN 64
43 static DEFINE_SPINLOCK(allpstore_lock);
44 static LIST_HEAD(allpstore);
46 struct pstore_private {
47 struct list_head list;
48 struct pstore_info *psi;
49 enum pstore_type_id type;
55 static int pstore_file_open(struct inode *inode, struct file *file)
57 file->private_data = inode->i_private;
61 static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
62 size_t count, loff_t *ppos)
64 struct pstore_private *ps = file->private_data;
66 return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
69 static const struct file_operations pstore_file_operations = {
70 .open = pstore_file_open,
71 .read = pstore_file_read,
72 .llseek = default_llseek,
76 * When a file is unlinked from our file system we call the
77 * platform driver to erase the record from persistent store.
79 static int pstore_unlink(struct inode *dir, struct dentry *dentry)
81 struct pstore_private *p = dentry->d_inode->i_private;
84 p->psi->erase(p->type, p->id, p->psi);
86 return simple_unlink(dir, dentry);
89 static void pstore_evict_inode(struct inode *inode)
91 struct pstore_private *p = inode->i_private;
96 spin_lock_irqsave(&allpstore_lock, flags);
98 spin_unlock_irqrestore(&allpstore_lock, flags);
103 static const struct inode_operations pstore_dir_inode_operations = {
104 .lookup = simple_lookup,
105 .unlink = pstore_unlink,
108 static struct inode *pstore_get_inode(struct super_block *sb)
110 struct inode *inode = new_inode(sb);
112 inode->i_ino = get_next_ino();
113 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
119 Opt_kmsg_bytes, Opt_err
122 static const match_table_t tokens = {
123 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
127 static void parse_options(char *options)
130 substring_t args[MAX_OPT_ARGS];
136 while ((p = strsep(&options, ",")) != NULL) {
142 token = match_token(p, tokens, args);
145 if (!match_int(&args[0], &option))
146 pstore_set_kmsg_bytes(option);
152 static int pstore_remount(struct super_block *sb, int *flags, char *data)
159 static const struct super_operations pstore_ops = {
160 .statfs = simple_statfs,
161 .drop_inode = generic_delete_inode,
162 .evict_inode = pstore_evict_inode,
163 .remount_fs = pstore_remount,
164 .show_options = generic_show_options,
167 static struct super_block *pstore_sb;
169 int pstore_is_mounted(void)
171 return pstore_sb != NULL;
175 * Make a regular file in the root directory of our file system.
176 * Load it up with "size" bytes of data from "buf".
177 * Set the mtime & ctime to the date that this record was originally stored.
179 int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
180 char *data, size_t size, struct timespec time,
181 struct pstore_info *psi)
183 struct dentry *root = pstore_sb->s_root;
184 struct dentry *dentry;
187 char name[PSTORE_NAMELEN];
188 struct pstore_private *private, *pos;
191 spin_lock_irqsave(&allpstore_lock, flags);
192 list_for_each_entry(pos, &allpstore, list) {
193 if (pos->type == type &&
200 spin_unlock_irqrestore(&allpstore_lock, flags);
205 inode = pstore_get_inode(pstore_sb);
208 inode->i_mode = S_IFREG | 0444;
209 inode->i_fop = &pstore_file_operations;
210 private = kmalloc(sizeof *private + size, GFP_KERNEL);
213 private->type = type;
218 case PSTORE_TYPE_DMESG:
219 sprintf(name, "dmesg-%s-%lld", psname, id);
221 case PSTORE_TYPE_MCE:
222 sprintf(name, "mce-%s-%lld", psname, id);
224 case PSTORE_TYPE_UNKNOWN:
225 sprintf(name, "unknown-%s-%lld", psname, id);
228 sprintf(name, "type%d-%s-%lld", type, psname, id);
232 mutex_lock(&root->d_inode->i_mutex);
235 dentry = d_alloc_name(root, name);
237 goto fail_lockedalloc;
239 memcpy(private->data, data, size);
240 inode->i_size = private->size = size;
242 inode->i_private = private;
245 inode->i_mtime = inode->i_ctime = time;
247 d_add(dentry, inode);
249 spin_lock_irqsave(&allpstore_lock, flags);
250 list_add(&private->list, &allpstore);
251 spin_unlock_irqrestore(&allpstore_lock, flags);
253 mutex_unlock(&root->d_inode->i_mutex);
258 mutex_unlock(&root->d_inode->i_mutex);
267 int pstore_fill_super(struct super_block *sb, void *data, int silent)
271 save_mount_options(sb, data);
275 sb->s_maxbytes = MAX_LFS_FILESIZE;
276 sb->s_blocksize = PAGE_CACHE_SIZE;
277 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
278 sb->s_magic = PSTOREFS_MAGIC;
279 sb->s_op = &pstore_ops;
284 inode = pstore_get_inode(sb);
286 inode->i_mode = S_IFDIR | 0755;
287 inode->i_op = &pstore_dir_inode_operations;
288 inode->i_fop = &simple_dir_operations;
291 sb->s_root = d_make_root(inode);
295 pstore_get_records(0);
300 static struct dentry *pstore_mount(struct file_system_type *fs_type,
301 int flags, const char *dev_name, void *data)
303 return mount_single(fs_type, flags, data, pstore_fill_super);
306 static void pstore_kill_sb(struct super_block *sb)
308 kill_litter_super(sb);
312 static struct file_system_type pstore_fs_type = {
314 .mount = pstore_mount,
315 .kill_sb = pstore_kill_sb,
318 static int __init init_pstore_fs(void)
320 return register_filesystem(&pstore_fs_type);
322 module_init(init_pstore_fs)
324 MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
325 MODULE_LICENSE("GPL");