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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/backing-dev.h>
  8 #include <linux/fs.h>
  9 #include <linux/blktrace_api.h>
 10 #include <asm/uaccess.h>
 11 
 12 static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
 13 {
 14         struct block_device *bdevp;
 15         struct gendisk *disk;
 16         struct hd_struct *part, *lpart;
 17         struct blkpg_ioctl_arg a;
 18         struct blkpg_partition p;
 19         struct disk_part_iter piter;
 20         long long start, length;
 21         int partno;
 22 
 23         if (!capable(CAP_SYS_ADMIN))
 24                 return -EACCES;
 25         if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
 26                 return -EFAULT;
 27         if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
 28                 return -EFAULT;
 29         disk = bdev->bd_disk;
 30         if (bdev != bdev->bd_contains)
 31                 return -EINVAL;
 32         partno = p.pno;
 33         if (partno <= 0)
 34                 return -EINVAL;
 35         switch (a.op) {
 36                 case BLKPG_ADD_PARTITION:
 37                         start = p.start >> 9;
 38                         length = p.length >> 9;
 39                         /* check for fit in a hd_struct */
 40                         if (sizeof(sector_t) == sizeof(long) &&
 41                             sizeof(long long) > sizeof(long)) {
 42                                 long pstart = start, plength = length;
 43                                 if (pstart != start || plength != length
 44                                     || pstart < 0 || plength < 0 || partno > 65535)
 45                                         return -EINVAL;
 46                         }
 47 
 48                         mutex_lock(&bdev->bd_mutex);
 49 
 50                         /* overlap? */
 51                         disk_part_iter_init(&piter, disk,
 52                                             DISK_PITER_INCL_EMPTY);
 53                         while ((part = disk_part_iter_next(&piter))) {
 54                                 if (!(start + length <= part->start_sect ||
 55                                       start >= part->start_sect + part->nr_sects)) {
 56                                         disk_part_iter_exit(&piter);
 57                                         mutex_unlock(&bdev->bd_mutex);
 58                                         return -EBUSY;
 59                                 }
 60                         }
 61                         disk_part_iter_exit(&piter);
 62 
 63                         /* all seems OK */
 64                         part = add_partition(disk, partno, start, length,
 65                                              ADDPART_FLAG_NONE, NULL);
 66                         mutex_unlock(&bdev->bd_mutex);
 67                         return PTR_ERR_OR_ZERO(part);
 68                 case BLKPG_DEL_PARTITION:
 69                         part = disk_get_part(disk, partno);
 70                         if (!part)
 71                                 return -ENXIO;
 72 
 73                         bdevp = bdget(part_devt(part));
 74                         disk_put_part(part);
 75                         if (!bdevp)
 76                                 return -ENOMEM;
 77 
 78                         mutex_lock(&bdevp->bd_mutex);
 79                         if (bdevp->bd_openers) {
 80                                 mutex_unlock(&bdevp->bd_mutex);
 81                                 bdput(bdevp);
 82                                 return -EBUSY;
 83                         }
 84                         /* all seems OK */
 85                         fsync_bdev(bdevp);
 86                         invalidate_bdev(bdevp);
 87 
 88                         mutex_lock_nested(&bdev->bd_mutex, 1);
 89                         delete_partition(disk, partno);
 90                         mutex_unlock(&bdev->bd_mutex);
 91                         mutex_unlock(&bdevp->bd_mutex);
 92                         bdput(bdevp);
 93 
 94                         return 0;
 95                 case BLKPG_RESIZE_PARTITION:
 96                         start = p.start >> 9;
 97                         /* new length of partition in bytes */
 98                         length = p.length >> 9;
 99                         /* check for fit in a hd_struct */
100                         if (sizeof(sector_t) == sizeof(long) &&
101                             sizeof(long long) > sizeof(long)) {
102                                 long pstart = start, plength = length;
103                                 if (pstart != start || plength != length
104                                     || pstart < 0 || plength < 0)
105                                         return -EINVAL;
106                         }
107                         part = disk_get_part(disk, partno);
108                         if (!part)
109                                 return -ENXIO;
110                         bdevp = bdget(part_devt(part));
111                         if (!bdevp) {
112                                 disk_put_part(part);
113                                 return -ENOMEM;
114                         }
115                         mutex_lock(&bdevp->bd_mutex);
116                         mutex_lock_nested(&bdev->bd_mutex, 1);
117                         if (start != part->start_sect) {
118                                 mutex_unlock(&bdevp->bd_mutex);
119                                 mutex_unlock(&bdev->bd_mutex);
120                                 bdput(bdevp);
121                                 disk_put_part(part);
122                                 return -EINVAL;
123                         }
124                         /* overlap? */
125                         disk_part_iter_init(&piter, disk,
126                                             DISK_PITER_INCL_EMPTY);
127                         while ((lpart = disk_part_iter_next(&piter))) {
128                                 if (lpart->partno != partno &&
129                                    !(start + length <= lpart->start_sect ||
130                                    start >= lpart->start_sect + lpart->nr_sects)
131                                    ) {
132                                         disk_part_iter_exit(&piter);
133                                         mutex_unlock(&bdevp->bd_mutex);
134                                         mutex_unlock(&bdev->bd_mutex);
135                                         bdput(bdevp);
136                                         disk_put_part(part);
137                                         return -EBUSY;
138                                 }
139                         }
140                         disk_part_iter_exit(&piter);
141                         part_nr_sects_write(part, (sector_t)length);
142                         i_size_write(bdevp->bd_inode, p.length);
143                         mutex_unlock(&bdevp->bd_mutex);
144                         mutex_unlock(&bdev->bd_mutex);
145                         bdput(bdevp);
146                         disk_put_part(part);
147                         return 0;
148                 default:
149                         return -EINVAL;
150         }
151 }
152 
153 /*
154  * This is an exported API for the block driver, and will not
155  * acquire bd_mutex. This API should be used in case that
156  * caller has held bd_mutex already.
157  */
158 int __blkdev_reread_part(struct block_device *bdev)
159 {
160         struct gendisk *disk = bdev->bd_disk;
161 
162         if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains)
163                 return -EINVAL;
164         if (!capable(CAP_SYS_ADMIN))
165                 return -EACCES;
166 
167         lockdep_assert_held(&bdev->bd_mutex);
168 
169         return rescan_partitions(disk, bdev);
170 }
171 EXPORT_SYMBOL(__blkdev_reread_part);
172 
173 /*
174  * This is an exported API for the block driver, and will
175  * try to acquire bd_mutex. If bd_mutex has been held already
176  * in current context, please call __blkdev_reread_part().
177  *
178  * Make sure the held locks in current context aren't required
179  * in open()/close() handler and I/O path for avoiding ABBA deadlock:
180  * - bd_mutex is held before calling block driver's open/close
181  *   handler
182  * - reading partition table may submit I/O to the block device
183  */
184 int blkdev_reread_part(struct block_device *bdev)
185 {
186         int res;
187 
188         mutex_lock(&bdev->bd_mutex);
189         res = __blkdev_reread_part(bdev);
190         mutex_unlock(&bdev->bd_mutex);
191 
192         return res;
193 }
194 EXPORT_SYMBOL(blkdev_reread_part);
195 
196 static int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
197                              uint64_t len, int secure)
198 {
199         unsigned long flags = 0;
200 
201         if (start & 511)
202                 return -EINVAL;
203         if (len & 511)
204                 return -EINVAL;
205         start >>= 9;
206         len >>= 9;
207 
208         if (start + len > (i_size_read(bdev->bd_inode) >> 9))
209                 return -EINVAL;
210         if (secure)
211                 flags |= BLKDEV_DISCARD_SECURE;
212         return blkdev_issue_discard(bdev, start, len, GFP_KERNEL, flags);
213 }
214 
215 static int blk_ioctl_zeroout(struct block_device *bdev, uint64_t start,
216                              uint64_t len)
217 {
218         if (start & 511)
219                 return -EINVAL;
220         if (len & 511)
221                 return -EINVAL;
222         start >>= 9;
223         len >>= 9;
224 
225         if (start + len > (i_size_read(bdev->bd_inode) >> 9))
226                 return -EINVAL;
227 
228         return blkdev_issue_zeroout(bdev, start, len, GFP_KERNEL, false);
229 }
230 
231 static int put_ushort(unsigned long arg, unsigned short val)
232 {
233         return put_user(val, (unsigned short __user *)arg);
234 }
235 
236 static int put_int(unsigned long arg, int val)
237 {
238         return put_user(val, (int __user *)arg);
239 }
240 
241 static int put_uint(unsigned long arg, unsigned int val)
242 {
243         return put_user(val, (unsigned int __user *)arg);
244 }
245 
246 static int put_long(unsigned long arg, long val)
247 {
248         return put_user(val, (long __user *)arg);
249 }
250 
251 static int put_ulong(unsigned long arg, unsigned long val)
252 {
253         return put_user(val, (unsigned long __user *)arg);
254 }
255 
256 static int put_u64(unsigned long arg, u64 val)
257 {
258         return put_user(val, (u64 __user *)arg);
259 }
260 
261 int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
262                         unsigned cmd, unsigned long arg)
263 {
264         struct gendisk *disk = bdev->bd_disk;
265 
266         if (disk->fops->ioctl)
267                 return disk->fops->ioctl(bdev, mode, cmd, arg);
268 
269         return -ENOTTY;
270 }
271 /*
272  * For the record: _GPL here is only because somebody decided to slap it
273  * on the previous export.  Sheer idiocy, since it wasn't copyrightable
274  * at all and could be open-coded without any exports by anybody who cares.
275  */
276 EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
277 
278 /*
279  * Is it an unrecognized ioctl? The correct returns are either
280  * ENOTTY (final) or ENOIOCTLCMD ("I don't know this one, try a
281  * fallback"). ENOIOCTLCMD gets turned into ENOTTY by the ioctl
282  * code before returning.
283  *
284  * Confused drivers sometimes return EINVAL, which is wrong. It
285  * means "I understood the ioctl command, but the parameters to
286  * it were wrong".
287  *
288  * We should aim to just fix the broken drivers, the EINVAL case
289  * should go away.
290  */
291 static inline int is_unrecognized_ioctl(int ret)
292 {
293         return  ret == -EINVAL ||
294                 ret == -ENOTTY ||
295                 ret == -ENOIOCTLCMD;
296 }
297 
298 /*
299  * always keep this in sync with compat_blkdev_ioctl()
300  */
301 int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
302                         unsigned long arg)
303 {
304         struct gendisk *disk = bdev->bd_disk;
305         struct backing_dev_info *bdi;
306         loff_t size;
307         int ret, n;
308         unsigned int max_sectors;
309 
310         switch(cmd) {
311         case BLKFLSBUF:
312                 if (!capable(CAP_SYS_ADMIN))
313                         return -EACCES;
314 
315                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
316                 if (!is_unrecognized_ioctl(ret))
317                         return ret;
318 
319                 fsync_bdev(bdev);
320                 invalidate_bdev(bdev);
321                 return 0;
322 
323         case BLKROSET:
324                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
325                 if (!is_unrecognized_ioctl(ret))
326                         return ret;
327                 if (!capable(CAP_SYS_ADMIN))
328                         return -EACCES;
329                 if (get_user(n, (int __user *)(arg)))
330                         return -EFAULT;
331                 set_device_ro(bdev, n);
332                 return 0;
333 
334         case BLKDISCARD:
335         case BLKSECDISCARD: {
336                 uint64_t range[2];
337 
338                 if (!(mode & FMODE_WRITE))
339                         return -EBADF;
340 
341                 if (copy_from_user(range, (void __user *)arg, sizeof(range)))
342                         return -EFAULT;
343 
344                 return blk_ioctl_discard(bdev, range[0], range[1],
345                                          cmd == BLKSECDISCARD);
346         }
347         case BLKZEROOUT: {
348                 uint64_t range[2];
349 
350                 if (!(mode & FMODE_WRITE))
351                         return -EBADF;
352 
353                 if (copy_from_user(range, (void __user *)arg, sizeof(range)))
354                         return -EFAULT;
355 
356                 return blk_ioctl_zeroout(bdev, range[0], range[1]);
357         }
358 
359         case HDIO_GETGEO: {
360                 struct hd_geometry geo;
361 
362                 if (!arg)
363                         return -EINVAL;
364                 if (!disk->fops->getgeo)
365                         return -ENOTTY;
366 
367                 /*
368                  * We need to set the startsect first, the driver may
369                  * want to override it.
370                  */
371                 memset(&geo, 0, sizeof(geo));
372                 geo.start = get_start_sect(bdev);
373                 ret = disk->fops->getgeo(bdev, &geo);
374                 if (ret)
375                         return ret;
376                 if (copy_to_user((struct hd_geometry __user *)arg, &geo,
377                                         sizeof(geo)))
378                         return -EFAULT;
379                 return 0;
380         }
381         case BLKRAGET:
382         case BLKFRAGET:
383                 if (!arg)
384                         return -EINVAL;
385                 bdi = blk_get_backing_dev_info(bdev);
386                 return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
387         case BLKROGET:
388                 return put_int(arg, bdev_read_only(bdev) != 0);
389         case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
390                 return put_int(arg, block_size(bdev));
391         case BLKSSZGET: /* get block device logical block size */
392                 return put_int(arg, bdev_logical_block_size(bdev));
393         case BLKPBSZGET: /* get block device physical block size */
394                 return put_uint(arg, bdev_physical_block_size(bdev));
395         case BLKIOMIN:
396                 return put_uint(arg, bdev_io_min(bdev));
397         case BLKIOOPT:
398                 return put_uint(arg, bdev_io_opt(bdev));
399         case BLKALIGNOFF:
400                 return put_int(arg, bdev_alignment_offset(bdev));
401         case BLKDISCARDZEROES:
402                 return put_uint(arg, bdev_discard_zeroes_data(bdev));
403         case BLKSECTGET:
404                 max_sectors = min_t(unsigned int, USHRT_MAX,
405                                     queue_max_sectors(bdev_get_queue(bdev)));
406                 return put_ushort(arg, max_sectors);
407         case BLKROTATIONAL:
408                 return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));
409         case BLKRASET:
410         case BLKFRASET:
411                 if(!capable(CAP_SYS_ADMIN))
412                         return -EACCES;
413                 bdi = blk_get_backing_dev_info(bdev);
414                 bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
415                 return 0;
416         case BLKBSZSET:
417                 /* set the logical block size */
418                 if (!capable(CAP_SYS_ADMIN))
419                         return -EACCES;
420                 if (!arg)
421                         return -EINVAL;
422                 if (get_user(n, (int __user *) arg))
423                         return -EFAULT;
424                 if (!(mode & FMODE_EXCL)) {
425                         bdgrab(bdev);
426                         if (blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
427                                 return -EBUSY;
428                 }
429                 ret = set_blocksize(bdev, n);
430                 if (!(mode & FMODE_EXCL))
431                         blkdev_put(bdev, mode | FMODE_EXCL);
432                 return ret;
433         case BLKPG:
434                 ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
435                 break;
436         case BLKRRPART:
437                 ret = blkdev_reread_part(bdev);
438                 break;
439         case BLKGETSIZE:
440                 size = i_size_read(bdev->bd_inode);
441                 if ((size >> 9) > ~0UL)
442                         return -EFBIG;
443                 return put_ulong(arg, size >> 9);
444         case BLKGETSIZE64:
445                 return put_u64(arg, i_size_read(bdev->bd_inode));
446         case BLKTRACESTART:
447         case BLKTRACESTOP:
448         case BLKTRACESETUP:
449         case BLKTRACETEARDOWN:
450                 ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
451                 break;
452         default:
453                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
454         }
455         return ret;
456 }
457 EXPORT_SYMBOL_GPL(blkdev_ioctl);
458 

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