| 1 | /* |
| 2 | * ltt/probes/ext4-trace.c |
| 3 | * |
| 4 | * ext4 tracepoint probes. |
| 5 | * |
| 6 | * (C) Copyright 2009 - Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> |
| 7 | * Dual LGPL v2.1/GPL v2 license. |
| 8 | */ |
| 9 | |
| 10 | #include <linux/module.h> |
| 11 | #include <linux/writeback.h> |
| 12 | #include <linux/debugfs.h> |
| 13 | #include <linux/mutex.h> |
| 14 | #include <linux/rcupdate.h> |
| 15 | #include <trace/events/ext4.h> |
| 16 | |
| 17 | #include "../ltt-tracer.h" |
| 18 | #include "../../fs/ext4/mballoc.h" |
| 19 | |
| 20 | static struct dentry *ext4_filter_dentry, *ext4_filter_dev_dentry, |
| 21 | *ext4_filter_inode_dentry; |
| 22 | static DEFINE_MUTEX(ext4_filter_mutex); |
| 23 | /* Make sure we don't race between module exit and file write */ |
| 24 | static int module_exits; |
| 25 | |
| 26 | struct rcu_dev_filter { |
| 27 | struct rcu_head rcu; |
| 28 | char devname[NAME_MAX]; |
| 29 | }; |
| 30 | |
| 31 | static struct rcu_dev_filter *dev_filter; |
| 32 | /* ~0UL inode_filter enables all inodes */ |
| 33 | static unsigned long inode_filter = ~0UL; |
| 34 | |
| 35 | /* |
| 36 | * Probes are executed in rcu_sched read-side critical section. |
| 37 | */ |
| 38 | |
| 39 | static int do_dev_filter(const char *dev) |
| 40 | { |
| 41 | struct rcu_dev_filter *ldev_filter = rcu_dereference(dev_filter); |
| 42 | |
| 43 | if (unlikely(ldev_filter)) |
| 44 | if (unlikely(strcmp(ldev_filter->devname, dev))) |
| 45 | return 0; |
| 46 | return 1; |
| 47 | } |
| 48 | |
| 49 | static int do_inode_filter(unsigned long ino) |
| 50 | { |
| 51 | if (unlikely(inode_filter != ~0UL)) |
| 52 | if (unlikely(inode_filter != ino)) |
| 53 | return 0; |
| 54 | return 1; |
| 55 | } |
| 56 | |
| 57 | /* |
| 58 | * Logical AND between dev and inode filter. |
| 59 | */ |
| 60 | static int do_filter(const char *dev, unsigned long ino) |
| 61 | { |
| 62 | if (unlikely(!do_dev_filter(dev))) |
| 63 | return 0; |
| 64 | if (unlikely(!do_inode_filter(ino))) |
| 65 | return 0; |
| 66 | return 1; |
| 67 | } |
| 68 | |
| 69 | |
| 70 | void probe_ext4_free_inode(void *data, struct inode *inode) |
| 71 | { |
| 72 | if (unlikely(!do_filter(inode->i_sb->s_id, inode->i_ino))) |
| 73 | return; |
| 74 | trace_mark_tp(ext4, free_inode, ext4_free_inode, |
| 75 | probe_ext4_free_inode, |
| 76 | "dev %s ino %lu mode %d uid %lu gid %lu blocks %llu", |
| 77 | inode->i_sb->s_id, inode->i_ino, inode->i_mode, |
| 78 | (unsigned long) inode->i_uid, (unsigned long) inode->i_gid, |
| 79 | (unsigned long long) inode->i_blocks); |
| 80 | } |
| 81 | |
| 82 | void probe_ext4_request_inode(void *data, struct inode *dir, int mode) |
| 83 | { |
| 84 | if (unlikely(!do_filter(dir->i_sb->s_id, dir->i_ino))) |
| 85 | return; |
| 86 | trace_mark_tp(ext4, request_inode, ext4_request_inode, |
| 87 | probe_ext4_request_inode, |
| 88 | "dev %s dir %lu mode %d", |
| 89 | dir->i_sb->s_id, dir->i_ino, mode); |
| 90 | } |
| 91 | |
| 92 | void probe_ext4_allocate_inode(void *data, struct inode *inode, struct inode *dir, int mode) |
| 93 | { |
| 94 | if (unlikely(!do_filter(inode->i_sb->s_id, inode->i_ino) |
| 95 | && !do_filter(dir->i_sb->s_id, dir->i_ino))) |
| 96 | return; |
| 97 | trace_mark_tp(ext4, allocate_inode, ext4_allocate_inode, |
| 98 | probe_ext4_allocate_inode, |
| 99 | "dev %s ino %lu dir %lu mode %d", |
| 100 | dir->i_sb->s_id, inode->i_ino, dir->i_ino, mode); |
| 101 | } |
| 102 | |
| 103 | void probe_ext4_write_begin(void *data, struct inode *inode, loff_t pos, unsigned int len, |
| 104 | unsigned int flags) |
| 105 | { |
| 106 | if (unlikely(!do_filter(inode->i_sb->s_id, inode->i_ino))) |
| 107 | return; |
| 108 | trace_mark_tp(ext4, write_begin, ext4_write_begin, |
| 109 | probe_ext4_write_begin, |
| 110 | "dev %s ino %lu pos %llu len %u flags %u", |
| 111 | inode->i_sb->s_id, inode->i_ino, |
| 112 | (unsigned long long) pos, len, flags); |
| 113 | } |
| 114 | |
| 115 | void probe_ext4_ordered_write_end(void *data, struct inode *inode, loff_t pos, |
| 116 | unsigned int len, unsigned int copied) |
| 117 | { |
| 118 | if (unlikely(!do_filter(inode->i_sb->s_id, inode->i_ino))) |
| 119 | return; |
| 120 | trace_mark_tp(ext4, ordered_write_end, ext4_ordered_write_end, |
| 121 | probe_ext4_ordered_write_end, |
| 122 | "dev %s ino %lu pos %llu len %u copied %u", |
| 123 | inode->i_sb->s_id, inode->i_ino, |
| 124 | (unsigned long long) pos, len, copied); |
| 125 | } |
| 126 | |
| 127 | void probe_ext4_writeback_write_end(void *data, struct inode *inode, loff_t pos, |
| 128 | unsigned int len, unsigned int copied) |
| 129 | { |
| 130 | if (unlikely(!do_filter(inode->i_sb->s_id, inode->i_ino))) |
| 131 | return; |
| 132 | trace_mark_tp(ext4, writeback_write_end, ext4_writeback_write_end, |
| 133 | probe_ext4_writeback_write_end, |
| 134 | "dev %s ino %lu pos %llu len %u copied %u", |
| 135 | inode->i_sb->s_id, inode->i_ino, |
| 136 | (unsigned long long) pos, len, copied); |
| 137 | } |
| 138 | |
| 139 | void probe_ext4_journalled_write_end(void *data, struct inode *inode, loff_t pos, |
| 140 | unsigned int len, unsigned int copied) |
| 141 | { |
| 142 | if (unlikely(!do_filter(inode->i_sb->s_id, inode->i_ino))) |
| 143 | return; |
| 144 | trace_mark_tp(ext4, journalled_write_end, ext4_journalled_write_end, |
| 145 | probe_ext4_journalled_write_end, |
| 146 | "dev %s ino %lu pos %llu len %u copied %u", |
| 147 | inode->i_sb->s_id, inode->i_ino, |
| 148 | (unsigned long long) pos, len, copied); |
| 149 | } |
| 150 | |
| 151 | /* |
| 152 | * note : wbc_flags will have to be decoded by userspace. |
| 153 | * #1x uses a single byte in the trace. Limits to 8 bits. |
| 154 | */ |
| 155 | void probe_ext4_da_writepages(void *data, struct inode *inode, |
| 156 | struct writeback_control *wbc) |
| 157 | { |
| 158 | if (unlikely(!do_filter(inode->i_sb->s_id, inode->i_ino))) |
| 159 | return; |
| 160 | trace_mark_tp(ext4, da_writepages, ext4_da_writepages, |
| 161 | probe_ext4_da_writepages, |
| 162 | "dev %s ino %lu nr_to_write %ld " |
| 163 | "pages_skipped %ld range_start %llu range_end %llu " |
| 164 | "wbc_flags(nonblocking,for_kupdate," |
| 165 | "for_reclaim,range_cyclic) #1x%u", |
| 166 | inode->i_sb->s_id, inode->i_ino, wbc->nr_to_write, |
| 167 | wbc->pages_skipped, |
| 168 | (unsigned long long) wbc->range_start, |
| 169 | (unsigned long long) wbc->range_end, |
| 170 | (wbc->nonblocking << 3) |
| 171 | | (wbc->for_kupdate << 2) |
| 172 | | (wbc->for_reclaim << 1) |
| 173 | | wbc->range_cyclic); |
| 174 | } |
| 175 | |
| 176 | /* |
| 177 | * note : wbc_flags will have to be decoded by userspace. |
| 178 | * #1x uses a single byte in the trace. Limits to 8 bits. |
| 179 | */ |
| 180 | void probe_ext4_da_writepages_result(void *data, struct inode *inode, |
| 181 | struct writeback_control *wbc, |
| 182 | int ret, int pages_written) |
| 183 | { |
| 184 | if (unlikely(!do_filter(inode->i_sb->s_id, inode->i_ino))) |
| 185 | return; |
| 186 | trace_mark_tp(ext4, da_writepages_result, ext4_da_writepages_result, |
| 187 | probe_ext4_da_writepages_result, |
| 188 | "dev %s ino %lu ret %d pages_written %d " |
| 189 | "pages_skipped %ld " |
| 190 | "wbc_flags(encountered_congestion," |
| 191 | "more_io,no_nrwrite_index_update) #1x%u", |
| 192 | inode->i_sb->s_id, inode->i_ino, ret, pages_written, |
| 193 | wbc->pages_skipped, |
| 194 | (wbc->encountered_congestion << 2) |
| 195 | | (wbc->more_io << 1) |
| 196 | | wbc->no_nrwrite_index_update); |
| 197 | } |
| 198 | |
| 199 | void probe_ext4_da_write_begin(void *data, struct inode *inode, loff_t pos, |
| 200 | unsigned int len, unsigned int flags) |
| 201 | { |
| 202 | if (unlikely(!do_filter(inode->i_sb->s_id, inode->i_ino))) |
| 203 | return; |
| 204 | trace_mark_tp(ext4, da_write_begin, ext4_da_write_begin, |
| 205 | probe_ext4_da_write_begin, |
| 206 | "dev %s ino %lu pos %llu len %u flags %u", |
| 207 | inode->i_sb->s_id, inode->i_ino, |
| 208 | (unsigned long long) pos, len, flags); |
| 209 | } |
| 210 | |
| 211 | void probe_ext4_da_write_end(void *data, struct inode *inode, loff_t pos, |
| 212 | unsigned int len, unsigned int copied) |
| 213 | { |
| 214 | if (unlikely(!do_filter(inode->i_sb->s_id, inode->i_ino))) |
| 215 | return; |
| 216 | trace_mark_tp(ext4, da_write_end, ext4_da_write_end, |
| 217 | probe_ext4_da_write_end, |
| 218 | "dev %s ino %lu pos %llu len %u copied %u", |
| 219 | inode->i_sb->s_id, inode->i_ino, |
| 220 | (unsigned long long) pos, len, copied); |
| 221 | } |
| 222 | |
| 223 | void probe_ext4_discard_blocks(void *data, struct super_block *sb, unsigned long long blk, |
| 224 | unsigned long long count) |
| 225 | { |
| 226 | if (unlikely(!do_dev_filter(sb->s_id))) |
| 227 | return; |
| 228 | trace_mark_tp(ext4, discard_blocks, ext4_discard_blocks, |
| 229 | probe_ext4_discard_blocks, |
| 230 | "dev %s blk %llu count %llu", |
| 231 | sb->s_id, blk, count); |
| 232 | } |
| 233 | |
| 234 | void probe_ext4_mb_new_inode_pa(void *data, struct ext4_allocation_context *ac, |
| 235 | struct ext4_prealloc_space *pa) |
| 236 | { |
| 237 | if (unlikely(!do_filter(ac->ac_sb->s_id, ac->ac_inode->i_ino))) |
| 238 | return; |
| 239 | trace_mark_tp(ext4, mb_new_inode_pa, ext4_mb_new_inode_pa, |
| 240 | probe_ext4_mb_new_inode_pa, |
| 241 | "dev %s ino %lu pstart %llu len %u lstart %u", |
| 242 | ac->ac_sb->s_id, ac->ac_inode->i_ino, pa->pa_pstart, |
| 243 | pa->pa_len, pa->pa_lstart); |
| 244 | } |
| 245 | |
| 246 | void probe_ext4_mb_new_group_pa(void *data, struct ext4_allocation_context *ac, |
| 247 | struct ext4_prealloc_space *pa) |
| 248 | { |
| 249 | if (unlikely(!do_dev_filter(ac->ac_sb->s_id))) |
| 250 | return; |
| 251 | trace_mark_tp(ext4, mb_new_group_pa, ext4_mb_new_group_pa, |
| 252 | probe_ext4_mb_new_group_pa, |
| 253 | "dev %s pstart %llu len %u lstart %u", |
| 254 | ac->ac_sb->s_id, pa->pa_pstart, |
| 255 | pa->pa_len, pa->pa_lstart); |
| 256 | } |
| 257 | |
| 258 | void probe_ext4_mb_release_inode_pa(void *data, struct ext4_allocation_context *ac, |
| 259 | struct ext4_prealloc_space *pa, |
| 260 | unsigned long long block, |
| 261 | unsigned int count) |
| 262 | { |
| 263 | if (unlikely(!do_filter(ac->ac_sb->s_id, ac->ac_inode->i_ino))) |
| 264 | return; |
| 265 | trace_mark_tp(ext4, mb_release_inode_pa, ext4_mb_release_inode_pa, |
| 266 | probe_ext4_mb_release_inode_pa, |
| 267 | "dev %s ino %lu block %llu count %u", |
| 268 | ac->ac_sb->s_id, pa->pa_inode->i_ino, block, count); |
| 269 | } |
| 270 | |
| 271 | void probe_ext4_mb_release_group_pa(void *data, struct ext4_allocation_context *ac, |
| 272 | struct ext4_prealloc_space *pa) |
| 273 | { |
| 274 | if (unlikely(!do_dev_filter(ac->ac_sb->s_id))) |
| 275 | return; |
| 276 | trace_mark_tp(ext4, mb_release_group_pa, ext4_mb_release_group_pa, |
| 277 | probe_ext4_mb_release_group_pa, |
| 278 | "dev %s pstart %llu len %d", |
| 279 | ac->ac_sb->s_id, pa->pa_pstart, pa->pa_len); |
| 280 | } |
| 281 | |
| 282 | void probe_ext4_discard_preallocations(void *data, struct inode *inode) |
| 283 | { |
| 284 | if (unlikely(!do_filter(inode->i_sb->s_id, inode->i_ino))) |
| 285 | return; |
| 286 | trace_mark_tp(ext4, discard_preallocations, |
| 287 | ext4_discard_preallocations, |
| 288 | probe_ext4_discard_preallocations, |
| 289 | "dev %s ino %lu", |
| 290 | inode->i_sb->s_id, inode->i_ino); |
| 291 | } |
| 292 | |
| 293 | void probe_ext4_mb_discard_preallocations(void *data, struct super_block *sb, int needed) |
| 294 | { |
| 295 | if (unlikely(!do_dev_filter(sb->s_id))) |
| 296 | return; |
| 297 | trace_mark_tp(ext4, mb_discard_preallocations, |
| 298 | ext4_mb_discard_preallocations, |
| 299 | probe_ext4_mb_discard_preallocations, |
| 300 | "dev %s needed %d", |
| 301 | sb->s_id, needed); |
| 302 | } |
| 303 | |
| 304 | void probe_ext4_request_blocks(void *data, struct ext4_allocation_request *ar) |
| 305 | { |
| 306 | if (ar->inode) { |
| 307 | if (unlikely(!do_filter(ar->inode->i_sb->s_id, |
| 308 | ar->inode->i_ino))) |
| 309 | return; |
| 310 | } else { |
| 311 | if (unlikely(!do_dev_filter(ar->inode->i_sb->s_id))) |
| 312 | return; |
| 313 | } |
| 314 | trace_mark_tp(ext4, request_blocks, ext4_request_blocks, |
| 315 | probe_ext4_request_blocks, |
| 316 | "dev %s flags %u len %u ino %lu " |
| 317 | "lblk %llu goal %llu lleft %llu lright %llu " |
| 318 | "pleft %llu pright %llu", |
| 319 | ar->inode->i_sb->s_id, ar->flags, ar->len, |
| 320 | ar->inode ? ar->inode->i_ino : 0, |
| 321 | (unsigned long long) ar->logical, |
| 322 | (unsigned long long) ar->goal, |
| 323 | (unsigned long long) ar->lleft, |
| 324 | (unsigned long long) ar->lright, |
| 325 | (unsigned long long) ar->pleft, |
| 326 | (unsigned long long) ar->pright); |
| 327 | } |
| 328 | |
| 329 | void probe_ext4_allocate_blocks(void *data, struct ext4_allocation_request *ar, |
| 330 | unsigned long long block) |
| 331 | { |
| 332 | if (ar->inode) { |
| 333 | if (unlikely(!do_filter(ar->inode->i_sb->s_id, |
| 334 | ar->inode->i_ino))) |
| 335 | return; |
| 336 | } else { |
| 337 | if (unlikely(!do_dev_filter(ar->inode->i_sb->s_id))) |
| 338 | return; |
| 339 | } |
| 340 | trace_mark_tp(ext4, allocate_blocks, ext4_allocate_blocks, |
| 341 | probe_ext4_allocate_blocks, |
| 342 | "dev %s block %llu flags %u len %u ino %lu " |
| 343 | "logical %llu goal %llu lleft %llu lright %llu " |
| 344 | "pleft %llu pright %llu", |
| 345 | ar->inode->i_sb->s_id, (unsigned long long) block, |
| 346 | ar->flags, ar->len, ar->inode ? ar->inode->i_ino : 0, |
| 347 | (unsigned long long) ar->logical, |
| 348 | (unsigned long long) ar->goal, |
| 349 | (unsigned long long) ar->lleft, |
| 350 | (unsigned long long) ar->lright, |
| 351 | (unsigned long long) ar->pleft, |
| 352 | (unsigned long long) ar->pright); |
| 353 | } |
| 354 | |
| 355 | void probe_ext4_free_blocks(void *data, struct inode *inode, __u64 block, |
| 356 | unsigned long count, int metadata) |
| 357 | { |
| 358 | if (unlikely(!do_filter(inode->i_sb->s_id, inode->i_ino))) |
| 359 | return; |
| 360 | trace_mark_tp(ext4, free_blocks, ext4_free_blocks, |
| 361 | probe_ext4_free_blocks, |
| 362 | "dev %s block %llu count %lu metadata %d ino %lu", |
| 363 | inode->i_sb->s_id, (unsigned long long)block, |
| 364 | count, metadata, inode->i_ino); |
| 365 | } |
| 366 | |
| 367 | void probe_ext4_sync_file(void *data, struct file *file, struct dentry *dentry, |
| 368 | int datasync) |
| 369 | { |
| 370 | if (unlikely(!do_dev_filter(dentry->d_inode->i_sb->s_id))) |
| 371 | return; |
| 372 | if (unlikely(!do_inode_filter(dentry->d_inode->i_ino) |
| 373 | && !do_inode_filter(dentry->d_parent->d_inode->i_ino))) |
| 374 | return; |
| 375 | trace_mark_tp(ext4, sync_file, ext4_sync_file, |
| 376 | probe_ext4_sync_file, |
| 377 | "dev %s datasync %d ino %ld parent %ld", |
| 378 | dentry->d_inode->i_sb->s_id, datasync, dentry->d_inode->i_ino, |
| 379 | dentry->d_parent->d_inode->i_ino); |
| 380 | } |
| 381 | |
| 382 | void probe_ext4_sync_fs(void *data, struct super_block *sb, int wait) |
| 383 | { |
| 384 | if (unlikely(!do_dev_filter(sb->s_id))) |
| 385 | return; |
| 386 | trace_mark_tp(ext4, sync_fs, ext4_sync_fs, |
| 387 | probe_ext4_sync_fs, |
| 388 | "dev %s wait %d", |
| 389 | sb->s_id, wait); |
| 390 | } |
| 391 | |
| 392 | static void free_dev_filter(struct rcu_head *head) |
| 393 | { |
| 394 | kfree(container_of(head, struct rcu_dev_filter, rcu)); |
| 395 | } |
| 396 | |
| 397 | static ssize_t dev_filter_op_write(struct file *file, |
| 398 | const char __user *user_buf, size_t count, loff_t *ppos) |
| 399 | { |
| 400 | int err = 0; |
| 401 | char buf[NAME_MAX]; |
| 402 | int buf_size; |
| 403 | char name[NAME_MAX]; |
| 404 | struct rcu_dev_filter *new, *old; |
| 405 | |
| 406 | mutex_lock(&ext4_filter_mutex); |
| 407 | if (module_exits) { |
| 408 | err = -EPERM; |
| 409 | goto error; |
| 410 | } |
| 411 | buf_size = min(count, sizeof(buf) - 1); |
| 412 | err = copy_from_user(buf, user_buf, buf_size); |
| 413 | if (err) |
| 414 | goto error; |
| 415 | buf[buf_size] = 0; |
| 416 | |
| 417 | if (sscanf(buf, "%s", name) != 1) { |
| 418 | err = -EPERM; |
| 419 | goto error; |
| 420 | } |
| 421 | |
| 422 | old = dev_filter; |
| 423 | |
| 424 | /* Empty string or * means all active */ |
| 425 | if (name[0] == '\0' || (name[0] == '*' && name[1] == '\0')) { |
| 426 | new = NULL; |
| 427 | } else { |
| 428 | new = kmalloc(sizeof(*new), GFP_KERNEL); |
| 429 | strcpy(new->devname, name); |
| 430 | } |
| 431 | |
| 432 | rcu_assign_pointer(dev_filter, new); |
| 433 | if (old) |
| 434 | call_rcu_sched(&old->rcu, free_dev_filter); |
| 435 | |
| 436 | mutex_unlock(&ext4_filter_mutex); |
| 437 | return count; |
| 438 | |
| 439 | error: |
| 440 | mutex_unlock(&ext4_filter_mutex); |
| 441 | return err; |
| 442 | } |
| 443 | |
| 444 | static ssize_t dev_filter_op_read(struct file *filp, char __user *buffer, |
| 445 | size_t count, loff_t *ppos) |
| 446 | { |
| 447 | ssize_t bcount; |
| 448 | const char *devname; |
| 449 | |
| 450 | mutex_lock(&ext4_filter_mutex); |
| 451 | if (!dev_filter) |
| 452 | devname = "*"; |
| 453 | else |
| 454 | devname = dev_filter->devname; |
| 455 | bcount = simple_read_from_buffer(buffer, count, ppos, |
| 456 | devname, strlen(devname)); |
| 457 | mutex_unlock(&ext4_filter_mutex); |
| 458 | return bcount; |
| 459 | } |
| 460 | |
| 461 | static struct file_operations ext4_dev_file_operations = { |
| 462 | .write = dev_filter_op_write, |
| 463 | .read = dev_filter_op_read, |
| 464 | }; |
| 465 | |
| 466 | static ssize_t inode_filter_op_write(struct file *file, |
| 467 | const char __user *user_buf, size_t count, loff_t *ppos) |
| 468 | { |
| 469 | int err = 0; |
| 470 | char buf[NAME_MAX]; |
| 471 | int buf_size; |
| 472 | char name[NAME_MAX]; |
| 473 | unsigned long inode_num; |
| 474 | |
| 475 | mutex_lock(&ext4_filter_mutex); |
| 476 | if (module_exits) { |
| 477 | err = -EPERM; |
| 478 | goto error; |
| 479 | } |
| 480 | buf_size = min(count, sizeof(buf) - 1); |
| 481 | err = copy_from_user(buf, user_buf, buf_size); |
| 482 | if (err) |
| 483 | goto error; |
| 484 | buf[buf_size] = 0; |
| 485 | |
| 486 | if (sscanf(buf, "%s", name) != 1) { |
| 487 | err = -EPERM; |
| 488 | goto error; |
| 489 | } |
| 490 | |
| 491 | /* Empty string or * means all active */ |
| 492 | if (name[0] == '\0' || (name[0] == '*' && name[1] == '\0')) { |
| 493 | inode_filter = ~0UL; |
| 494 | } else { |
| 495 | if (sscanf(buf, "%lu", &inode_num) != 1) { |
| 496 | err = -EPERM; |
| 497 | goto error; |
| 498 | } |
| 499 | inode_filter = inode_num; |
| 500 | } |
| 501 | |
| 502 | mutex_unlock(&ext4_filter_mutex); |
| 503 | return count; |
| 504 | |
| 505 | error: |
| 506 | mutex_unlock(&ext4_filter_mutex); |
| 507 | return err; |
| 508 | } |
| 509 | |
| 510 | static ssize_t inode_filter_op_read(struct file *filp, char __user *buffer, |
| 511 | size_t count, loff_t *ppos) |
| 512 | { |
| 513 | ssize_t bcount; |
| 514 | char inode_str[NAME_MAX]; |
| 515 | |
| 516 | mutex_lock(&ext4_filter_mutex); |
| 517 | if (inode_filter == ~0UL) |
| 518 | strcpy(inode_str, "*"); |
| 519 | else { |
| 520 | bcount = snprintf(inode_str, sizeof(inode_str), "%lu", |
| 521 | inode_filter); |
| 522 | if (bcount == sizeof(inode_str)) |
| 523 | bcount = -ENOSPC; |
| 524 | if (bcount < 0) |
| 525 | goto end; |
| 526 | } |
| 527 | bcount = simple_read_from_buffer(buffer, count, ppos, |
| 528 | inode_str, strlen(inode_str)); |
| 529 | end: |
| 530 | mutex_unlock(&ext4_filter_mutex); |
| 531 | return bcount; |
| 532 | } |
| 533 | |
| 534 | static struct file_operations ext4_inode_file_operations = { |
| 535 | .write = inode_filter_op_write, |
| 536 | .read = inode_filter_op_read, |
| 537 | }; |
| 538 | |
| 539 | static void release_filter_dev(void) |
| 540 | { |
| 541 | struct rcu_dev_filter *old; |
| 542 | |
| 543 | mutex_lock(&ext4_filter_mutex); |
| 544 | module_exits = 1; |
| 545 | old = dev_filter; |
| 546 | rcu_assign_pointer(dev_filter, NULL); |
| 547 | if (old) |
| 548 | call_rcu_sched(&old->rcu, free_dev_filter); |
| 549 | mutex_unlock(&ext4_filter_mutex); |
| 550 | } |
| 551 | |
| 552 | static int __init filter_init(void) |
| 553 | { |
| 554 | struct dentry *filter_root_dentry; |
| 555 | int err = 0; |
| 556 | |
| 557 | filter_root_dentry = get_filter_root(); |
| 558 | if (!filter_root_dentry) { |
| 559 | err = -ENOENT; |
| 560 | goto end; |
| 561 | } |
| 562 | |
| 563 | ext4_filter_dentry = debugfs_create_dir("ext4", filter_root_dentry); |
| 564 | |
| 565 | if (IS_ERR(ext4_filter_dentry) || !ext4_filter_dentry) { |
| 566 | printk(KERN_ERR "Failed to create ext4 filter file\n"); |
| 567 | err = -ENOMEM; |
| 568 | goto end; |
| 569 | } |
| 570 | |
| 571 | ext4_filter_dev_dentry = debugfs_create_file("dev", S_IWUSR, |
| 572 | ext4_filter_dentry, NULL, &ext4_dev_file_operations); |
| 573 | if (IS_ERR(ext4_filter_dev_dentry) || !ext4_filter_dev_dentry) { |
| 574 | printk(KERN_ERR "Failed to create ext4 dev filter file\n"); |
| 575 | err = -ENOMEM; |
| 576 | goto release_filter_dentry; |
| 577 | } |
| 578 | |
| 579 | ext4_filter_inode_dentry = debugfs_create_file("inode", S_IWUSR, |
| 580 | ext4_filter_dentry, NULL, &ext4_inode_file_operations); |
| 581 | if (IS_ERR(ext4_filter_inode_dentry) || !ext4_filter_inode_dentry) { |
| 582 | printk(KERN_ERR "Failed to create ext4 inode filter file\n"); |
| 583 | err = -ENOMEM; |
| 584 | goto release_filter_dev_dentry; |
| 585 | } |
| 586 | |
| 587 | goto end; |
| 588 | |
| 589 | release_filter_dev_dentry: |
| 590 | debugfs_remove(ext4_filter_dev_dentry); |
| 591 | release_filter_dentry: |
| 592 | debugfs_remove(ext4_filter_dentry); |
| 593 | release_filter_dev(); |
| 594 | end: |
| 595 | return err; |
| 596 | } |
| 597 | |
| 598 | static void __exit filter_exit(void) |
| 599 | { |
| 600 | debugfs_remove(ext4_filter_dev_dentry); |
| 601 | debugfs_remove(ext4_filter_inode_dentry); |
| 602 | debugfs_remove(ext4_filter_dentry); |
| 603 | release_filter_dev(); |
| 604 | } |
| 605 | |
| 606 | module_init(filter_init); |
| 607 | module_exit(filter_exit); |
| 608 | |
| 609 | MODULE_LICENSE("GPL and additional rights"); |
| 610 | MODULE_AUTHOR("Mathieu Desnoyers"); |
| 611 | MODULE_DESCRIPTION("ext4 Tracepoint Probes"); |