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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/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>
38
39#include "internal.h"
40
41#define PSTORE_NAMELEN 64
42
43static DEFINE_SPINLOCK(allpstore_lock);
44static LIST_HEAD(allpstore);
45
46struct pstore_private {
47 struct list_head list;
48 struct pstore_info *psi;
49 enum pstore_type_id type;
50 u64 id;
51 ssize_t size;
52 char data[];
53};
54
55static int pstore_file_open(struct inode *inode, struct file *file)
56{
57 file->private_data = inode->i_private;
58 return 0;
59}
60
61static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
62 size_t count, loff_t *ppos)
63{
64 struct pstore_private *ps = file->private_data;
65
66 return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
67}
68
69static const struct file_operations pstore_file_operations = {
70 .open = pstore_file_open,
71 .read = pstore_file_read,
72 .llseek = default_llseek,
73};
74
75
76
77
78
79static int pstore_unlink(struct inode *dir, struct dentry *dentry)
80{
81 struct pstore_private *p = dentry->d_inode->i_private;
82
83 p->psi->erase(p->type, p->id, p->psi);
84
85 return simple_unlink(dir, dentry);
86}
87
88static void pstore_evict_inode(struct inode *inode)
89{
90 struct pstore_private *p = inode->i_private;
91 unsigned long flags;
92
93 end_writeback(inode);
94 if (p) {
95 spin_lock_irqsave(&allpstore_lock, flags);
96 list_del(&p->list);
97 spin_unlock_irqrestore(&allpstore_lock, flags);
98 kfree(p);
99 }
100}
101
102static const struct inode_operations pstore_dir_inode_operations = {
103 .lookup = simple_lookup,
104 .unlink = pstore_unlink,
105};
106
107static struct inode *pstore_get_inode(struct super_block *sb,
108 const struct inode *dir, int mode, dev_t dev)
109{
110 struct inode *inode = new_inode(sb);
111
112 if (inode) {
113 inode->i_ino = get_next_ino();
114 inode->i_uid = inode->i_gid = 0;
115 inode->i_mode = mode;
116 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
117 switch (mode & S_IFMT) {
118 case S_IFREG:
119 inode->i_fop = &pstore_file_operations;
120 break;
121 case S_IFDIR:
122 inode->i_op = &pstore_dir_inode_operations;
123 inode->i_fop = &simple_dir_operations;
124 inc_nlink(inode);
125 break;
126 }
127 }
128 return inode;
129}
130
131enum {
132 Opt_kmsg_bytes, Opt_err
133};
134
135static const match_table_t tokens = {
136 {Opt_kmsg_bytes, "kmsg_bytes=%u"},
137 {Opt_err, NULL}
138};
139
140static void parse_options(char *options)
141{
142 char *p;
143 substring_t args[MAX_OPT_ARGS];
144 int option;
145
146 if (!options)
147 return;
148
149 while ((p = strsep(&options, ",")) != NULL) {
150 int token;
151
152 if (!*p)
153 continue;
154
155 token = match_token(p, tokens, args);
156 switch (token) {
157 case Opt_kmsg_bytes:
158 if (!match_int(&args[0], &option))
159 pstore_set_kmsg_bytes(option);
160 break;
161 }
162 }
163}
164
165static int pstore_remount(struct super_block *sb, int *flags, char *data)
166{
167 parse_options(data);
168
169 return 0;
170}
171
172static const struct super_operations pstore_ops = {
173 .statfs = simple_statfs,
174 .drop_inode = generic_delete_inode,
175 .evict_inode = pstore_evict_inode,
176 .remount_fs = pstore_remount,
177 .show_options = generic_show_options,
178};
179
180static struct super_block *pstore_sb;
181
182int pstore_is_mounted(void)
183{
184 return pstore_sb != NULL;
185}
186
187
188
189
190
191
192int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
193 char *data, size_t size, struct timespec time,
194 struct pstore_info *psi)
195{
196 struct dentry *root = pstore_sb->s_root;
197 struct dentry *dentry;
198 struct inode *inode;
199 int rc = 0;
200 char name[PSTORE_NAMELEN];
201 struct pstore_private *private, *pos;
202 unsigned long flags;
203
204 spin_lock_irqsave(&allpstore_lock, flags);
205 list_for_each_entry(pos, &allpstore, list) {
206 if (pos->type == type &&
207 pos->id == id &&
208 pos->psi == psi) {
209 rc = -EEXIST;
210 break;
211 }
212 }
213 spin_unlock_irqrestore(&allpstore_lock, flags);
214 if (rc)
215 return rc;
216
217 rc = -ENOMEM;
218 inode = pstore_get_inode(pstore_sb, root->d_inode, S_IFREG | 0444, 0);
219 if (!inode)
220 goto fail;
221 private = kmalloc(sizeof *private + size, GFP_KERNEL);
222 if (!private)
223 goto fail_alloc;
224 private->type = type;
225 private->id = id;
226 private->psi = psi;
227
228 switch (type) {
229 case PSTORE_TYPE_DMESG:
230 sprintf(name, "dmesg-%s-%lld", psname, id);
231 break;
232 case PSTORE_TYPE_MCE:
233 sprintf(name, "mce-%s-%lld", psname, id);
234 break;
235 case PSTORE_TYPE_UNKNOWN:
236 sprintf(name, "unknown-%s-%lld", psname, id);
237 break;
238 default:
239 sprintf(name, "type%d-%s-%lld", type, psname, id);
240 break;
241 }
242
243 mutex_lock(&root->d_inode->i_mutex);
244
245 rc = -ENOSPC;
246 dentry = d_alloc_name(root, name);
247 if (IS_ERR(dentry))
248 goto fail_lockedalloc;
249
250 memcpy(private->data, data, size);
251 inode->i_size = private->size = size;
252
253 inode->i_private = private;
254
255 if (time.tv_sec)
256 inode->i_mtime = inode->i_ctime = time;
257
258 d_add(dentry, inode);
259
260 spin_lock_irqsave(&allpstore_lock, flags);
261 list_add(&private->list, &allpstore);
262 spin_unlock_irqrestore(&allpstore_lock, flags);
263
264 mutex_unlock(&root->d_inode->i_mutex);
265
266 return 0;
267
268fail_lockedalloc:
269 mutex_unlock(&root->d_inode->i_mutex);
270 kfree(private);
271fail_alloc:
272 iput(inode);
273
274fail:
275 return rc;
276}
277
278int pstore_fill_super(struct super_block *sb, void *data, int silent)
279{
280 struct inode *inode = NULL;
281 struct dentry *root;
282 int err;
283
284 save_mount_options(sb, data);
285
286 pstore_sb = sb;
287
288 sb->s_maxbytes = MAX_LFS_FILESIZE;
289 sb->s_blocksize = PAGE_CACHE_SIZE;
290 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
291 sb->s_magic = PSTOREFS_MAGIC;
292 sb->s_op = &pstore_ops;
293 sb->s_time_gran = 1;
294
295 parse_options(data);
296
297 inode = pstore_get_inode(sb, NULL, S_IFDIR | 0755, 0);
298 if (!inode) {
299 err = -ENOMEM;
300 goto fail;
301 }
302
303 inode->i_op = &pstore_dir_inode_operations;
304
305 root = d_alloc_root(inode);
306 sb->s_root = root;
307 if (!root) {
308 err = -ENOMEM;
309 goto fail;
310 }
311
312 pstore_get_records(0);
313
314 return 0;
315fail:
316 iput(inode);
317 return err;
318}
319
320static struct dentry *pstore_mount(struct file_system_type *fs_type,
321 int flags, const char *dev_name, void *data)
322{
323 return mount_single(fs_type, flags, data, pstore_fill_super);
324}
325
326static void pstore_kill_sb(struct super_block *sb)
327{
328 kill_litter_super(sb);
329 pstore_sb = NULL;
330}
331
332static struct file_system_type pstore_fs_type = {
333 .name = "pstore",
334 .mount = pstore_mount,
335 .kill_sb = pstore_kill_sb,
336};
337
338static int __init init_pstore_fs(void)
339{
340 return register_filesystem(&pstore_fs_type);
341}
342module_init(init_pstore_fs)
343
344MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
345MODULE_LICENSE("GPL");
346
