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Linux/block/ioctl.c

  1 #include <linux/capability.h>
  2 #include <linux/blkdev.h>
  3 #include <linux/export.h>
  4 #include <linux/gfp.h>
  5 #include <linux/blkpg.h>
  6 #include <linux/hdreg.h>
  7 #include <linux/badblocks.h>
  8 #include <linux/backing-dev.h>
  9 #include <linux/fs.h>
 10 #include <linux/blktrace_api.h>
 11 #include <linux/pr.h>
 12 #include <asm/uaccess.h>
 13 
 14 static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
 15 {
 16         struct block_device *bdevp;
 17         struct gendisk *disk;
 18         struct hd_struct *part, *lpart;
 19         struct blkpg_ioctl_arg a;
 20         struct blkpg_partition p;
 21         struct disk_part_iter piter;
 22         long long start, length;
 23         int partno;
 24 
 25         if (!capable(CAP_SYS_ADMIN))
 26                 return -EACCES;
 27         if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
 28                 return -EFAULT;
 29         if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
 30                 return -EFAULT;
 31         disk = bdev->bd_disk;
 32         if (bdev != bdev->bd_contains)
 33                 return -EINVAL;
 34         partno = p.pno;
 35         if (partno <= 0)
 36                 return -EINVAL;
 37         switch (a.op) {
 38                 case BLKPG_ADD_PARTITION:
 39                         start = p.start >> 9;
 40                         length = p.length >> 9;
 41                         /* check for fit in a hd_struct */
 42                         if (sizeof(sector_t) == sizeof(long) &&
 43                             sizeof(long long) > sizeof(long)) {
 44                                 long pstart = start, plength = length;
 45                                 if (pstart != start || plength != length
 46                                     || pstart < 0 || plength < 0 || partno > 65535)
 47                                         return -EINVAL;
 48                         }
 49 
 50                         mutex_lock(&bdev->bd_mutex);
 51 
 52                         /* overlap? */
 53                         disk_part_iter_init(&piter, disk,
 54                                             DISK_PITER_INCL_EMPTY);
 55                         while ((part = disk_part_iter_next(&piter))) {
 56                                 if (!(start + length <= part->start_sect ||
 57                                       start >= part->start_sect + part->nr_sects)) {
 58                                         disk_part_iter_exit(&piter);
 59                                         mutex_unlock(&bdev->bd_mutex);
 60                                         return -EBUSY;
 61                                 }
 62                         }
 63                         disk_part_iter_exit(&piter);
 64 
 65                         /* all seems OK */
 66                         part = add_partition(disk, partno, start, length,
 67                                              ADDPART_FLAG_NONE, NULL);
 68                         mutex_unlock(&bdev->bd_mutex);
 69                         return PTR_ERR_OR_ZERO(part);
 70                 case BLKPG_DEL_PARTITION:
 71                         part = disk_get_part(disk, partno);
 72                         if (!part)
 73                                 return -ENXIO;
 74 
 75                         bdevp = bdget(part_devt(part));
 76                         disk_put_part(part);
 77                         if (!bdevp)
 78                                 return -ENOMEM;
 79 
 80                         mutex_lock(&bdevp->bd_mutex);
 81                         if (bdevp->bd_openers) {
 82                                 mutex_unlock(&bdevp->bd_mutex);
 83                                 bdput(bdevp);
 84                                 return -EBUSY;
 85                         }
 86                         /* all seems OK */
 87                         fsync_bdev(bdevp);
 88                         invalidate_bdev(bdevp);
 89 
 90                         mutex_lock_nested(&bdev->bd_mutex, 1);
 91                         delete_partition(disk, partno);
 92                         mutex_unlock(&bdev->bd_mutex);
 93                         mutex_unlock(&bdevp->bd_mutex);
 94                         bdput(bdevp);
 95 
 96                         return 0;
 97                 case BLKPG_RESIZE_PARTITION:
 98                         start = p.start >> 9;
 99                         /* new length of partition in bytes */
100                         length = p.length >> 9;
101                         /* check for fit in a hd_struct */
102                         if (sizeof(sector_t) == sizeof(long) &&
103                             sizeof(long long) > sizeof(long)) {
104                                 long pstart = start, plength = length;
105                                 if (pstart != start || plength != length
106                                     || pstart < 0 || plength < 0)
107                                         return -EINVAL;
108                         }
109                         part = disk_get_part(disk, partno);
110                         if (!part)
111                                 return -ENXIO;
112                         bdevp = bdget(part_devt(part));
113                         if (!bdevp) {
114                                 disk_put_part(part);
115                                 return -ENOMEM;
116                         }
117                         mutex_lock(&bdevp->bd_mutex);
118                         mutex_lock_nested(&bdev->bd_mutex, 1);
119                         if (start != part->start_sect) {
120                                 mutex_unlock(&bdevp->bd_mutex);
121                                 mutex_unlock(&bdev->bd_mutex);
122                                 bdput(bdevp);
123                                 disk_put_part(part);
124                                 return -EINVAL;
125                         }
126                         /* overlap? */
127                         disk_part_iter_init(&piter, disk,
128                                             DISK_PITER_INCL_EMPTY);
129                         while ((lpart = disk_part_iter_next(&piter))) {
130                                 if (lpart->partno != partno &&
131                                    !(start + length <= lpart->start_sect ||
132                                    start >= lpart->start_sect + lpart->nr_sects)
133                                    ) {
134                                         disk_part_iter_exit(&piter);
135                                         mutex_unlock(&bdevp->bd_mutex);
136                                         mutex_unlock(&bdev->bd_mutex);
137                                         bdput(bdevp);
138                                         disk_put_part(part);
139                                         return -EBUSY;
140                                 }
141                         }
142                         disk_part_iter_exit(&piter);
143                         part_nr_sects_write(part, (sector_t)length);
144                         i_size_write(bdevp->bd_inode, p.length);
145                         mutex_unlock(&bdevp->bd_mutex);
146                         mutex_unlock(&bdev->bd_mutex);
147                         bdput(bdevp);
148                         disk_put_part(part);
149                         return 0;
150                 default:
151                         return -EINVAL;
152         }
153 }
154 
155 /*
156  * This is an exported API for the block driver, and will not
157  * acquire bd_mutex. This API should be used in case that
158  * caller has held bd_mutex already.
159  */
160 int __blkdev_reread_part(struct block_device *bdev)
161 {
162         struct gendisk *disk = bdev->bd_disk;
163 
164         if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains)
165                 return -EINVAL;
166         if (!capable(CAP_SYS_ADMIN))
167                 return -EACCES;
168 
169         lockdep_assert_held(&bdev->bd_mutex);
170 
171         return rescan_partitions(disk, bdev);
172 }
173 EXPORT_SYMBOL(__blkdev_reread_part);
174 
175 /*
176  * This is an exported API for the block driver, and will
177  * try to acquire bd_mutex. If bd_mutex has been held already
178  * in current context, please call __blkdev_reread_part().
179  *
180  * Make sure the held locks in current context aren't required
181  * in open()/close() handler and I/O path for avoiding ABBA deadlock:
182  * - bd_mutex is held before calling block driver's open/close
183  *   handler
184  * - reading partition table may submit I/O to the block device
185  */
186 int blkdev_reread_part(struct block_device *bdev)
187 {
188         int res;
189 
190         mutex_lock(&bdev->bd_mutex);
191         res = __blkdev_reread_part(bdev);
192         mutex_unlock(&bdev->bd_mutex);
193 
194         return res;
195 }
196 EXPORT_SYMBOL(blkdev_reread_part);
197 
198 static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode,
199                 unsigned long arg, unsigned long flags)
200 {
201         uint64_t range[2];
202         uint64_t start, len;
203 
204         if (!(mode & FMODE_WRITE))
205                 return -EBADF;
206 
207         if (copy_from_user(range, (void __user *)arg, sizeof(range)))
208                 return -EFAULT;
209 
210         start = range[0];
211         len = range[1];
212 
213         if (start & 511)
214                 return -EINVAL;
215         if (len & 511)
216                 return -EINVAL;
217         start >>= 9;
218         len >>= 9;
219 
220         if (start + len > (i_size_read(bdev->bd_inode) >> 9))
221                 return -EINVAL;
222         return blkdev_issue_discard(bdev, start, len, GFP_KERNEL, flags);
223 }
224 
225 static int blk_ioctl_zeroout(struct block_device *bdev, fmode_t mode,
226                 unsigned long arg)
227 {
228         uint64_t range[2];
229         uint64_t start, len;
230 
231         if (!(mode & FMODE_WRITE))
232                 return -EBADF;
233 
234         if (copy_from_user(range, (void __user *)arg, sizeof(range)))
235                 return -EFAULT;
236 
237         start = range[0];
238         len = range[1];
239 
240         if (start & 511)
241                 return -EINVAL;
242         if (len & 511)
243                 return -EINVAL;
244         start >>= 9;
245         len >>= 9;
246 
247         if (start + len > (i_size_read(bdev->bd_inode) >> 9))
248                 return -EINVAL;
249 
250         return blkdev_issue_zeroout(bdev, start, len, GFP_KERNEL, false);
251 }
252 
253 static int put_ushort(unsigned long arg, unsigned short val)
254 {
255         return put_user(val, (unsigned short __user *)arg);
256 }
257 
258 static int put_int(unsigned long arg, int val)
259 {
260         return put_user(val, (int __user *)arg);
261 }
262 
263 static int put_uint(unsigned long arg, unsigned int val)
264 {
265         return put_user(val, (unsigned int __user *)arg);
266 }
267 
268 static int put_long(unsigned long arg, long val)
269 {
270         return put_user(val, (long __user *)arg);
271 }
272 
273 static int put_ulong(unsigned long arg, unsigned long val)
274 {
275         return put_user(val, (unsigned long __user *)arg);
276 }
277 
278 static int put_u64(unsigned long arg, u64 val)
279 {
280         return put_user(val, (u64 __user *)arg);
281 }
282 
283 int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
284                         unsigned cmd, unsigned long arg)
285 {
286         struct gendisk *disk = bdev->bd_disk;
287 
288         if (disk->fops->ioctl)
289                 return disk->fops->ioctl(bdev, mode, cmd, arg);
290 
291         return -ENOTTY;
292 }
293 /*
294  * For the record: _GPL here is only because somebody decided to slap it
295  * on the previous export.  Sheer idiocy, since it wasn't copyrightable
296  * at all and could be open-coded without any exports by anybody who cares.
297  */
298 EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
299 
300 static int blkdev_pr_register(struct block_device *bdev,
301                 struct pr_registration __user *arg)
302 {
303         const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
304         struct pr_registration reg;
305 
306         if (!capable(CAP_SYS_ADMIN))
307                 return -EPERM;
308         if (!ops || !ops->pr_register)
309                 return -EOPNOTSUPP;
310         if (copy_from_user(&reg, arg, sizeof(reg)))
311                 return -EFAULT;
312 
313         if (reg.flags & ~PR_FL_IGNORE_KEY)
314                 return -EOPNOTSUPP;
315         return ops->pr_register(bdev, reg.old_key, reg.new_key, reg.flags);
316 }
317 
318 static int blkdev_pr_reserve(struct block_device *bdev,
319                 struct pr_reservation __user *arg)
320 {
321         const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
322         struct pr_reservation rsv;
323 
324         if (!capable(CAP_SYS_ADMIN))
325                 return -EPERM;
326         if (!ops || !ops->pr_reserve)
327                 return -EOPNOTSUPP;
328         if (copy_from_user(&rsv, arg, sizeof(rsv)))
329                 return -EFAULT;
330 
331         if (rsv.flags & ~PR_FL_IGNORE_KEY)
332                 return -EOPNOTSUPP;
333         return ops->pr_reserve(bdev, rsv.key, rsv.type, rsv.flags);
334 }
335 
336 static int blkdev_pr_release(struct block_device *bdev,
337                 struct pr_reservation __user *arg)
338 {
339         const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
340         struct pr_reservation rsv;
341 
342         if (!capable(CAP_SYS_ADMIN))
343                 return -EPERM;
344         if (!ops || !ops->pr_release)
345                 return -EOPNOTSUPP;
346         if (copy_from_user(&rsv, arg, sizeof(rsv)))
347                 return -EFAULT;
348 
349         if (rsv.flags)
350                 return -EOPNOTSUPP;
351         return ops->pr_release(bdev, rsv.key, rsv.type);
352 }
353 
354 static int blkdev_pr_preempt(struct block_device *bdev,
355                 struct pr_preempt __user *arg, bool abort)
356 {
357         const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
358         struct pr_preempt p;
359 
360         if (!capable(CAP_SYS_ADMIN))
361                 return -EPERM;
362         if (!ops || !ops->pr_preempt)
363                 return -EOPNOTSUPP;
364         if (copy_from_user(&p, arg, sizeof(p)))
365                 return -EFAULT;
366 
367         if (p.flags)
368                 return -EOPNOTSUPP;
369         return ops->pr_preempt(bdev, p.old_key, p.new_key, p.type, abort);
370 }
371 
372 static int blkdev_pr_clear(struct block_device *bdev,
373                 struct pr_clear __user *arg)
374 {
375         const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
376         struct pr_clear c;
377 
378         if (!capable(CAP_SYS_ADMIN))
379                 return -EPERM;
380         if (!ops || !ops->pr_clear)
381                 return -EOPNOTSUPP;
382         if (copy_from_user(&c, arg, sizeof(c)))
383                 return -EFAULT;
384 
385         if (c.flags)
386                 return -EOPNOTSUPP;
387         return ops->pr_clear(bdev, c.key);
388 }
389 
390 /*
391  * Is it an unrecognized ioctl? The correct returns are either
392  * ENOTTY (final) or ENOIOCTLCMD ("I don't know this one, try a
393  * fallback"). ENOIOCTLCMD gets turned into ENOTTY by the ioctl
394  * code before returning.
395  *
396  * Confused drivers sometimes return EINVAL, which is wrong. It
397  * means "I understood the ioctl command, but the parameters to
398  * it were wrong".
399  *
400  * We should aim to just fix the broken drivers, the EINVAL case
401  * should go away.
402  */
403 static inline int is_unrecognized_ioctl(int ret)
404 {
405         return  ret == -EINVAL ||
406                 ret == -ENOTTY ||
407                 ret == -ENOIOCTLCMD;
408 }
409 
410 #ifdef CONFIG_FS_DAX
411 bool blkdev_dax_capable(struct block_device *bdev)
412 {
413         struct gendisk *disk = bdev->bd_disk;
414 
415         if (!disk->fops->direct_access)
416                 return false;
417 
418         /*
419          * If the partition is not aligned on a page boundary, we can't
420          * do dax I/O to it.
421          */
422         if ((bdev->bd_part->start_sect % (PAGE_SIZE / 512))
423                         || (bdev->bd_part->nr_sects % (PAGE_SIZE / 512)))
424                 return false;
425 
426         /*
427          * If the device has known bad blocks, force all I/O through the
428          * driver / page cache.
429          *
430          * TODO: support finer grained dax error handling
431          */
432         if (disk->bb && disk->bb->count)
433                 return false;
434 
435         return true;
436 }
437 #endif
438 
439 static int blkdev_flushbuf(struct block_device *bdev, fmode_t mode,
440                 unsigned cmd, unsigned long arg)
441 {
442         int ret;
443 
444         if (!capable(CAP_SYS_ADMIN))
445                 return -EACCES;
446 
447         ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
448         if (!is_unrecognized_ioctl(ret))
449                 return ret;
450 
451         fsync_bdev(bdev);
452         invalidate_bdev(bdev);
453         return 0;
454 }
455 
456 static int blkdev_roset(struct block_device *bdev, fmode_t mode,
457                 unsigned cmd, unsigned long arg)
458 {
459         int ret, n;
460 
461         ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
462         if (!is_unrecognized_ioctl(ret))
463                 return ret;
464         if (!capable(CAP_SYS_ADMIN))
465                 return -EACCES;
466         if (get_user(n, (int __user *)arg))
467                 return -EFAULT;
468         set_device_ro(bdev, n);
469         return 0;
470 }
471 
472 static int blkdev_getgeo(struct block_device *bdev,
473                 struct hd_geometry __user *argp)
474 {
475         struct gendisk *disk = bdev->bd_disk;
476         struct hd_geometry geo;
477         int ret;
478 
479         if (!argp)
480                 return -EINVAL;
481         if (!disk->fops->getgeo)
482                 return -ENOTTY;
483 
484         /*
485          * We need to set the startsect first, the driver may
486          * want to override it.
487          */
488         memset(&geo, 0, sizeof(geo));
489         geo.start = get_start_sect(bdev);
490         ret = disk->fops->getgeo(bdev, &geo);
491         if (ret)
492                 return ret;
493         if (copy_to_user(argp, &geo, sizeof(geo)))
494                 return -EFAULT;
495         return 0;
496 }
497 
498 /* set the logical block size */
499 static int blkdev_bszset(struct block_device *bdev, fmode_t mode,
500                 int __user *argp)
501 {
502         int ret, n;
503 
504         if (!capable(CAP_SYS_ADMIN))
505                 return -EACCES;
506         if (!argp)
507                 return -EINVAL;
508         if (get_user(n, argp))
509                 return -EFAULT;
510 
511         if (!(mode & FMODE_EXCL)) {
512                 bdgrab(bdev);
513                 if (blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
514                         return -EBUSY;
515         }
516 
517         ret = set_blocksize(bdev, n);
518         if (!(mode & FMODE_EXCL))
519                 blkdev_put(bdev, mode | FMODE_EXCL);
520         return ret;
521 }
522 
523 /*
524  * always keep this in sync with compat_blkdev_ioctl()
525  */
526 int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
527                         unsigned long arg)
528 {
529         struct backing_dev_info *bdi;
530         void __user *argp = (void __user *)arg;
531         loff_t size;
532         unsigned int max_sectors;
533 
534         switch (cmd) {
535         case BLKFLSBUF:
536                 return blkdev_flushbuf(bdev, mode, cmd, arg);
537         case BLKROSET:
538                 return blkdev_roset(bdev, mode, cmd, arg);
539         case BLKDISCARD:
540                 return blk_ioctl_discard(bdev, mode, arg, 0);
541         case BLKSECDISCARD:
542                 return blk_ioctl_discard(bdev, mode, arg,
543                                 BLKDEV_DISCARD_SECURE);
544         case BLKZEROOUT:
545                 return blk_ioctl_zeroout(bdev, mode, arg);
546         case HDIO_GETGEO:
547                 return blkdev_getgeo(bdev, argp);
548         case BLKRAGET:
549         case BLKFRAGET:
550                 if (!arg)
551                         return -EINVAL;
552                 bdi = blk_get_backing_dev_info(bdev);
553                 return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
554         case BLKROGET:
555                 return put_int(arg, bdev_read_only(bdev) != 0);
556         case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
557                 return put_int(arg, block_size(bdev));
558         case BLKSSZGET: /* get block device logical block size */
559                 return put_int(arg, bdev_logical_block_size(bdev));
560         case BLKPBSZGET: /* get block device physical block size */
561                 return put_uint(arg, bdev_physical_block_size(bdev));
562         case BLKIOMIN:
563                 return put_uint(arg, bdev_io_min(bdev));
564         case BLKIOOPT:
565                 return put_uint(arg, bdev_io_opt(bdev));
566         case BLKALIGNOFF:
567                 return put_int(arg, bdev_alignment_offset(bdev));
568         case BLKDISCARDZEROES:
569                 return put_uint(arg, bdev_discard_zeroes_data(bdev));
570         case BLKSECTGET:
571                 max_sectors = min_t(unsigned int, USHRT_MAX,
572                                     queue_max_sectors(bdev_get_queue(bdev)));
573                 return put_ushort(arg, max_sectors);
574         case BLKROTATIONAL:
575                 return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));
576         case BLKRASET:
577         case BLKFRASET:
578                 if(!capable(CAP_SYS_ADMIN))
579                         return -EACCES;
580                 bdi = blk_get_backing_dev_info(bdev);
581                 bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
582                 return 0;
583         case BLKBSZSET:
584                 return blkdev_bszset(bdev, mode, argp);
585         case BLKPG:
586                 return blkpg_ioctl(bdev, argp);
587         case BLKRRPART:
588                 return blkdev_reread_part(bdev);
589         case BLKGETSIZE:
590                 size = i_size_read(bdev->bd_inode);
591                 if ((size >> 9) > ~0UL)
592                         return -EFBIG;
593                 return put_ulong(arg, size >> 9);
594         case BLKGETSIZE64:
595                 return put_u64(arg, i_size_read(bdev->bd_inode));
596         case BLKTRACESTART:
597         case BLKTRACESTOP:
598         case BLKTRACESETUP:
599         case BLKTRACETEARDOWN:
600                 return blk_trace_ioctl(bdev, cmd, argp);
601         case BLKDAXGET:
602                 return put_int(arg, !!(bdev->bd_inode->i_flags & S_DAX));
603                 break;
604         case IOC_PR_REGISTER:
605                 return blkdev_pr_register(bdev, argp);
606         case IOC_PR_RESERVE:
607                 return blkdev_pr_reserve(bdev, argp);
608         case IOC_PR_RELEASE:
609                 return blkdev_pr_release(bdev, argp);
610         case IOC_PR_PREEMPT:
611                 return blkdev_pr_preempt(bdev, argp, false);
612         case IOC_PR_PREEMPT_ABORT:
613                 return blkdev_pr_preempt(bdev, argp, true);
614         case IOC_PR_CLEAR:
615                 return blkdev_pr_clear(bdev, argp);
616         default:
617                 return __blkdev_driver_ioctl(bdev, mode, cmd, arg);
618         }
619 }
620 EXPORT_SYMBOL_GPL(blkdev_ioctl);
621 

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