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 ssize_t pstore_file_read(struct file *file, char __user *userbuf,
56 size_t count, loff_t *ppos)
58 struct pstore_private *ps = file->private_data;
60 return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
63 static const struct file_operations pstore_file_operations = {
65 .read = pstore_file_read,
66 .llseek = default_llseek,
70 * When a file is unlinked from our file system we call the
71 * platform driver to erase the record from persistent store.
73 static int pstore_unlink(struct inode *dir, struct dentry *dentry)
75 struct pstore_private *p = dentry->d_inode->i_private;
78 p->psi->erase(p->type, p->id, p->psi);
80 return simple_unlink(dir, dentry);
83 static void pstore_evict_inode(struct inode *inode)
85 struct pstore_private *p = inode->i_private;
90 spin_lock_irqsave(&allpstore_lock, flags);
92 spin_unlock_irqrestore(&allpstore_lock, flags);
97 static const struct inode_operations pstore_dir_inode_operations = {
98 .lookup = simple_lookup,
99 .unlink = pstore_unlink,
102 static struct inode *pstore_get_inode(struct super_block *sb,
103 const struct inode *dir, int mode, dev_t dev)
105 struct inode *inode = new_inode(sb);
108 inode->i_ino = get_next_ino();
109 inode->i_uid = inode->i_gid = 0;
110 inode->i_mode = mode;
111 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
112 switch (mode & S_IFMT) {
114 inode->i_fop = &pstore_file_operations;
117 inode->i_op = &pstore_dir_inode_operations;
118 inode->i_fop = &simple_dir_operations;
127 Opt_kmsg_bytes, Opt_err
130 static const match_table_t tokens = {
131 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
135 static void parse_options(char *options)
138 substring_t args[MAX_OPT_ARGS];
144 while ((p = strsep(&options, ",")) != NULL) {
150 token = match_token(p, tokens, args);
153 if (!match_int(&args[0], &option))
154 pstore_set_kmsg_bytes(option);
160 static int pstore_remount(struct super_block *sb, int *flags, char *data)
167 static const struct super_operations pstore_ops = {
168 .statfs = simple_statfs,
169 .drop_inode = generic_delete_inode,
170 .evict_inode = pstore_evict_inode,
171 .remount_fs = pstore_remount,
172 .show_options = generic_show_options,
175 static struct super_block *pstore_sb;
177 int pstore_is_mounted(void)
179 return pstore_sb != NULL;
183 * Make a regular file in the root directory of our file system.
184 * Load it up with "size" bytes of data from "buf".
185 * Set the mtime & ctime to the date that this record was originally stored.
187 int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
188 char *data, size_t size, struct timespec time,
189 struct pstore_info *psi)
191 struct dentry *root = pstore_sb->s_root;
192 struct dentry *dentry;
195 char name[PSTORE_NAMELEN];
196 struct pstore_private *private, *pos;
199 spin_lock_irqsave(&allpstore_lock, flags);
200 list_for_each_entry(pos, &allpstore, list) {
201 if (pos->type == type &&
208 spin_unlock_irqrestore(&allpstore_lock, flags);
213 inode = pstore_get_inode(pstore_sb, root->d_inode, S_IFREG | 0444, 0);
216 private = kmalloc(sizeof *private + size, GFP_KERNEL);
219 private->type = type;
224 case PSTORE_TYPE_DMESG:
225 sprintf(name, "dmesg-%s-%lld", psname, id);
227 case PSTORE_TYPE_MCE:
228 sprintf(name, "mce-%s-%lld", psname, id);
230 case PSTORE_TYPE_UNKNOWN:
231 sprintf(name, "unknown-%s-%lld", psname, id);
234 sprintf(name, "type%d-%s-%lld", type, psname, id);
238 mutex_lock(&root->d_inode->i_mutex);
241 dentry = d_alloc_name(root, name);
243 goto fail_lockedalloc;
245 memcpy(private->data, data, size);
246 inode->i_size = private->size = size;
248 inode->i_private = private;
251 inode->i_mtime = inode->i_ctime = time;
253 d_add(dentry, inode);
255 spin_lock_irqsave(&allpstore_lock, flags);
256 list_add(&private->list, &allpstore);
257 spin_unlock_irqrestore(&allpstore_lock, flags);
259 mutex_unlock(&root->d_inode->i_mutex);
264 mutex_unlock(&root->d_inode->i_mutex);
273 int pstore_fill_super(struct super_block *sb, void *data, int silent)
277 save_mount_options(sb, data);
281 sb->s_maxbytes = MAX_LFS_FILESIZE;
282 sb->s_blocksize = PAGE_CACHE_SIZE;
283 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
284 sb->s_magic = PSTOREFS_MAGIC;
285 sb->s_op = &pstore_ops;
290 inode = pstore_get_inode(sb, NULL, S_IFDIR | 0755, 0);
292 /* override ramfs "dir" options so we catch unlink(2) */
293 inode->i_op = &pstore_dir_inode_operations;
295 sb->s_root = d_make_root(inode);
299 pstore_get_records(0);
304 static struct dentry *pstore_mount(struct file_system_type *fs_type,
305 int flags, const char *dev_name, void *data)
307 return mount_single(fs_type, flags, data, pstore_fill_super);
310 static void pstore_kill_sb(struct super_block *sb)
312 kill_litter_super(sb);
316 static struct file_system_type pstore_fs_type = {
318 .mount = pstore_mount,
319 .kill_sb = pstore_kill_sb,
322 static int __init init_pstore_fs(void)
324 return register_filesystem(&pstore_fs_type);
326 module_init(init_pstore_fs)
328 MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
329 MODULE_LICENSE("GPL");