| 1 | /* |
| 2 | * linux/fs/block_dev.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 5 | * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE |
| 6 | */ |
| 7 | |
| 8 | #include <linux/init.h> |
| 9 | #include <linux/mm.h> |
| 10 | #include <linux/fcntl.h> |
| 11 | #include <linux/slab.h> |
| 12 | #include <linux/kmod.h> |
| 13 | #include <linux/major.h> |
| 14 | #include <linux/device_cgroup.h> |
| 15 | #include <linux/highmem.h> |
| 16 | #include <linux/blkdev.h> |
| 17 | #include <linux/backing-dev.h> |
| 18 | #include <linux/module.h> |
| 19 | #include <linux/blkpg.h> |
| 20 | #include <linux/magic.h> |
| 21 | #include <linux/buffer_head.h> |
| 22 | #include <linux/swap.h> |
| 23 | #include <linux/pagevec.h> |
| 24 | #include <linux/writeback.h> |
| 25 | #include <linux/mpage.h> |
| 26 | #include <linux/mount.h> |
| 27 | #include <linux/uio.h> |
| 28 | #include <linux/namei.h> |
| 29 | #include <linux/log2.h> |
| 30 | #include <linux/cleancache.h> |
| 31 | #include <linux/dax.h> |
| 32 | #include <asm/uaccess.h> |
| 33 | #include "internal.h" |
| 34 | |
| 35 | struct bdev_inode { |
| 36 | struct block_device bdev; |
| 37 | struct inode vfs_inode; |
| 38 | }; |
| 39 | |
| 40 | static const struct address_space_operations def_blk_aops; |
| 41 | |
| 42 | static inline struct bdev_inode *BDEV_I(struct inode *inode) |
| 43 | { |
| 44 | return container_of(inode, struct bdev_inode, vfs_inode); |
| 45 | } |
| 46 | |
| 47 | struct block_device *I_BDEV(struct inode *inode) |
| 48 | { |
| 49 | return &BDEV_I(inode)->bdev; |
| 50 | } |
| 51 | EXPORT_SYMBOL(I_BDEV); |
| 52 | |
| 53 | static void bdev_write_inode(struct block_device *bdev) |
| 54 | { |
| 55 | struct inode *inode = bdev->bd_inode; |
| 56 | int ret; |
| 57 | |
| 58 | spin_lock(&inode->i_lock); |
| 59 | while (inode->i_state & I_DIRTY) { |
| 60 | spin_unlock(&inode->i_lock); |
| 61 | ret = write_inode_now(inode, true); |
| 62 | if (ret) { |
| 63 | char name[BDEVNAME_SIZE]; |
| 64 | pr_warn_ratelimited("VFS: Dirty inode writeback failed " |
| 65 | "for block device %s (err=%d).\n", |
| 66 | bdevname(bdev, name), ret); |
| 67 | } |
| 68 | spin_lock(&inode->i_lock); |
| 69 | } |
| 70 | spin_unlock(&inode->i_lock); |
| 71 | } |
| 72 | |
| 73 | /* Kill _all_ buffers and pagecache , dirty or not.. */ |
| 74 | void kill_bdev(struct block_device *bdev) |
| 75 | { |
| 76 | struct address_space *mapping = bdev->bd_inode->i_mapping; |
| 77 | |
| 78 | if (mapping->nrpages == 0 && mapping->nrexceptional == 0) |
| 79 | return; |
| 80 | |
| 81 | invalidate_bh_lrus(); |
| 82 | truncate_inode_pages(mapping, 0); |
| 83 | } |
| 84 | EXPORT_SYMBOL(kill_bdev); |
| 85 | |
| 86 | /* Invalidate clean unused buffers and pagecache. */ |
| 87 | void invalidate_bdev(struct block_device *bdev) |
| 88 | { |
| 89 | struct address_space *mapping = bdev->bd_inode->i_mapping; |
| 90 | |
| 91 | if (mapping->nrpages == 0) |
| 92 | return; |
| 93 | |
| 94 | invalidate_bh_lrus(); |
| 95 | lru_add_drain_all(); /* make sure all lru add caches are flushed */ |
| 96 | invalidate_mapping_pages(mapping, 0, -1); |
| 97 | /* 99% of the time, we don't need to flush the cleancache on the bdev. |
| 98 | * But, for the strange corners, lets be cautious |
| 99 | */ |
| 100 | cleancache_invalidate_inode(mapping); |
| 101 | } |
| 102 | EXPORT_SYMBOL(invalidate_bdev); |
| 103 | |
| 104 | int set_blocksize(struct block_device *bdev, int size) |
| 105 | { |
| 106 | /* Size must be a power of two, and between 512 and PAGE_SIZE */ |
| 107 | if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size)) |
| 108 | return -EINVAL; |
| 109 | |
| 110 | /* Size cannot be smaller than the size supported by the device */ |
| 111 | if (size < bdev_logical_block_size(bdev)) |
| 112 | return -EINVAL; |
| 113 | |
| 114 | /* Don't change the size if it is same as current */ |
| 115 | if (bdev->bd_block_size != size) { |
| 116 | sync_blockdev(bdev); |
| 117 | bdev->bd_block_size = size; |
| 118 | bdev->bd_inode->i_blkbits = blksize_bits(size); |
| 119 | kill_bdev(bdev); |
| 120 | } |
| 121 | return 0; |
| 122 | } |
| 123 | |
| 124 | EXPORT_SYMBOL(set_blocksize); |
| 125 | |
| 126 | int sb_set_blocksize(struct super_block *sb, int size) |
| 127 | { |
| 128 | if (set_blocksize(sb->s_bdev, size)) |
| 129 | return 0; |
| 130 | /* If we get here, we know size is power of two |
| 131 | * and it's value is between 512 and PAGE_SIZE */ |
| 132 | sb->s_blocksize = size; |
| 133 | sb->s_blocksize_bits = blksize_bits(size); |
| 134 | return sb->s_blocksize; |
| 135 | } |
| 136 | |
| 137 | EXPORT_SYMBOL(sb_set_blocksize); |
| 138 | |
| 139 | int sb_min_blocksize(struct super_block *sb, int size) |
| 140 | { |
| 141 | int minsize = bdev_logical_block_size(sb->s_bdev); |
| 142 | if (size < minsize) |
| 143 | size = minsize; |
| 144 | return sb_set_blocksize(sb, size); |
| 145 | } |
| 146 | |
| 147 | EXPORT_SYMBOL(sb_min_blocksize); |
| 148 | |
| 149 | static int |
| 150 | blkdev_get_block(struct inode *inode, sector_t iblock, |
| 151 | struct buffer_head *bh, int create) |
| 152 | { |
| 153 | bh->b_bdev = I_BDEV(inode); |
| 154 | bh->b_blocknr = iblock; |
| 155 | set_buffer_mapped(bh); |
| 156 | return 0; |
| 157 | } |
| 158 | |
| 159 | static struct inode *bdev_file_inode(struct file *file) |
| 160 | { |
| 161 | return file->f_mapping->host; |
| 162 | } |
| 163 | |
| 164 | static ssize_t |
| 165 | blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset) |
| 166 | { |
| 167 | struct file *file = iocb->ki_filp; |
| 168 | struct inode *inode = bdev_file_inode(file); |
| 169 | |
| 170 | if (IS_DAX(inode)) |
| 171 | return dax_do_io(iocb, inode, iter, offset, blkdev_get_block, |
| 172 | NULL, DIO_SKIP_DIO_COUNT); |
| 173 | return __blockdev_direct_IO(iocb, inode, I_BDEV(inode), iter, offset, |
| 174 | blkdev_get_block, NULL, NULL, |
| 175 | DIO_SKIP_DIO_COUNT); |
| 176 | } |
| 177 | |
| 178 | int __sync_blockdev(struct block_device *bdev, int wait) |
| 179 | { |
| 180 | if (!bdev) |
| 181 | return 0; |
| 182 | if (!wait) |
| 183 | return filemap_flush(bdev->bd_inode->i_mapping); |
| 184 | return filemap_write_and_wait(bdev->bd_inode->i_mapping); |
| 185 | } |
| 186 | |
| 187 | /* |
| 188 | * Write out and wait upon all the dirty data associated with a block |
| 189 | * device via its mapping. Does not take the superblock lock. |
| 190 | */ |
| 191 | int sync_blockdev(struct block_device *bdev) |
| 192 | { |
| 193 | return __sync_blockdev(bdev, 1); |
| 194 | } |
| 195 | EXPORT_SYMBOL(sync_blockdev); |
| 196 | |
| 197 | /* |
| 198 | * Write out and wait upon all dirty data associated with this |
| 199 | * device. Filesystem data as well as the underlying block |
| 200 | * device. Takes the superblock lock. |
| 201 | */ |
| 202 | int fsync_bdev(struct block_device *bdev) |
| 203 | { |
| 204 | struct super_block *sb = get_super(bdev); |
| 205 | if (sb) { |
| 206 | int res = sync_filesystem(sb); |
| 207 | drop_super(sb); |
| 208 | return res; |
| 209 | } |
| 210 | return sync_blockdev(bdev); |
| 211 | } |
| 212 | EXPORT_SYMBOL(fsync_bdev); |
| 213 | |
| 214 | /** |
| 215 | * freeze_bdev -- lock a filesystem and force it into a consistent state |
| 216 | * @bdev: blockdevice to lock |
| 217 | * |
| 218 | * If a superblock is found on this device, we take the s_umount semaphore |
| 219 | * on it to make sure nobody unmounts until the snapshot creation is done. |
| 220 | * The reference counter (bd_fsfreeze_count) guarantees that only the last |
| 221 | * unfreeze process can unfreeze the frozen filesystem actually when multiple |
| 222 | * freeze requests arrive simultaneously. It counts up in freeze_bdev() and |
| 223 | * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze |
| 224 | * actually. |
| 225 | */ |
| 226 | struct super_block *freeze_bdev(struct block_device *bdev) |
| 227 | { |
| 228 | struct super_block *sb; |
| 229 | int error = 0; |
| 230 | |
| 231 | mutex_lock(&bdev->bd_fsfreeze_mutex); |
| 232 | if (++bdev->bd_fsfreeze_count > 1) { |
| 233 | /* |
| 234 | * We don't even need to grab a reference - the first call |
| 235 | * to freeze_bdev grab an active reference and only the last |
| 236 | * thaw_bdev drops it. |
| 237 | */ |
| 238 | sb = get_super(bdev); |
| 239 | drop_super(sb); |
| 240 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
| 241 | return sb; |
| 242 | } |
| 243 | |
| 244 | sb = get_active_super(bdev); |
| 245 | if (!sb) |
| 246 | goto out; |
| 247 | if (sb->s_op->freeze_super) |
| 248 | error = sb->s_op->freeze_super(sb); |
| 249 | else |
| 250 | error = freeze_super(sb); |
| 251 | if (error) { |
| 252 | deactivate_super(sb); |
| 253 | bdev->bd_fsfreeze_count--; |
| 254 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
| 255 | return ERR_PTR(error); |
| 256 | } |
| 257 | deactivate_super(sb); |
| 258 | out: |
| 259 | sync_blockdev(bdev); |
| 260 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
| 261 | return sb; /* thaw_bdev releases s->s_umount */ |
| 262 | } |
| 263 | EXPORT_SYMBOL(freeze_bdev); |
| 264 | |
| 265 | /** |
| 266 | * thaw_bdev -- unlock filesystem |
| 267 | * @bdev: blockdevice to unlock |
| 268 | * @sb: associated superblock |
| 269 | * |
| 270 | * Unlocks the filesystem and marks it writeable again after freeze_bdev(). |
| 271 | */ |
| 272 | int thaw_bdev(struct block_device *bdev, struct super_block *sb) |
| 273 | { |
| 274 | int error = -EINVAL; |
| 275 | |
| 276 | mutex_lock(&bdev->bd_fsfreeze_mutex); |
| 277 | if (!bdev->bd_fsfreeze_count) |
| 278 | goto out; |
| 279 | |
| 280 | error = 0; |
| 281 | if (--bdev->bd_fsfreeze_count > 0) |
| 282 | goto out; |
| 283 | |
| 284 | if (!sb) |
| 285 | goto out; |
| 286 | |
| 287 | if (sb->s_op->thaw_super) |
| 288 | error = sb->s_op->thaw_super(sb); |
| 289 | else |
| 290 | error = thaw_super(sb); |
| 291 | if (error) { |
| 292 | bdev->bd_fsfreeze_count++; |
| 293 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
| 294 | return error; |
| 295 | } |
| 296 | out: |
| 297 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
| 298 | return 0; |
| 299 | } |
| 300 | EXPORT_SYMBOL(thaw_bdev); |
| 301 | |
| 302 | static int blkdev_writepage(struct page *page, struct writeback_control *wbc) |
| 303 | { |
| 304 | return block_write_full_page(page, blkdev_get_block, wbc); |
| 305 | } |
| 306 | |
| 307 | static int blkdev_readpage(struct file * file, struct page * page) |
| 308 | { |
| 309 | return block_read_full_page(page, blkdev_get_block); |
| 310 | } |
| 311 | |
| 312 | static int blkdev_readpages(struct file *file, struct address_space *mapping, |
| 313 | struct list_head *pages, unsigned nr_pages) |
| 314 | { |
| 315 | return mpage_readpages(mapping, pages, nr_pages, blkdev_get_block); |
| 316 | } |
| 317 | |
| 318 | static int blkdev_write_begin(struct file *file, struct address_space *mapping, |
| 319 | loff_t pos, unsigned len, unsigned flags, |
| 320 | struct page **pagep, void **fsdata) |
| 321 | { |
| 322 | return block_write_begin(mapping, pos, len, flags, pagep, |
| 323 | blkdev_get_block); |
| 324 | } |
| 325 | |
| 326 | static int blkdev_write_end(struct file *file, struct address_space *mapping, |
| 327 | loff_t pos, unsigned len, unsigned copied, |
| 328 | struct page *page, void *fsdata) |
| 329 | { |
| 330 | int ret; |
| 331 | ret = block_write_end(file, mapping, pos, len, copied, page, fsdata); |
| 332 | |
| 333 | unlock_page(page); |
| 334 | page_cache_release(page); |
| 335 | |
| 336 | return ret; |
| 337 | } |
| 338 | |
| 339 | /* |
| 340 | * private llseek: |
| 341 | * for a block special file file_inode(file)->i_size is zero |
| 342 | * so we compute the size by hand (just as in block_read/write above) |
| 343 | */ |
| 344 | static loff_t block_llseek(struct file *file, loff_t offset, int whence) |
| 345 | { |
| 346 | struct inode *bd_inode = bdev_file_inode(file); |
| 347 | loff_t retval; |
| 348 | |
| 349 | inode_lock(bd_inode); |
| 350 | retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode)); |
| 351 | inode_unlock(bd_inode); |
| 352 | return retval; |
| 353 | } |
| 354 | |
| 355 | int blkdev_fsync(struct file *filp, loff_t start, loff_t end, int datasync) |
| 356 | { |
| 357 | struct inode *bd_inode = bdev_file_inode(filp); |
| 358 | struct block_device *bdev = I_BDEV(bd_inode); |
| 359 | int error; |
| 360 | |
| 361 | error = filemap_write_and_wait_range(filp->f_mapping, start, end); |
| 362 | if (error) |
| 363 | return error; |
| 364 | |
| 365 | /* |
| 366 | * There is no need to serialise calls to blkdev_issue_flush with |
| 367 | * i_mutex and doing so causes performance issues with concurrent |
| 368 | * O_SYNC writers to a block device. |
| 369 | */ |
| 370 | error = blkdev_issue_flush(bdev, GFP_KERNEL, NULL); |
| 371 | if (error == -EOPNOTSUPP) |
| 372 | error = 0; |
| 373 | |
| 374 | return error; |
| 375 | } |
| 376 | EXPORT_SYMBOL(blkdev_fsync); |
| 377 | |
| 378 | /** |
| 379 | * bdev_read_page() - Start reading a page from a block device |
| 380 | * @bdev: The device to read the page from |
| 381 | * @sector: The offset on the device to read the page to (need not be aligned) |
| 382 | * @page: The page to read |
| 383 | * |
| 384 | * On entry, the page should be locked. It will be unlocked when the page |
| 385 | * has been read. If the block driver implements rw_page synchronously, |
| 386 | * that will be true on exit from this function, but it need not be. |
| 387 | * |
| 388 | * Errors returned by this function are usually "soft", eg out of memory, or |
| 389 | * queue full; callers should try a different route to read this page rather |
| 390 | * than propagate an error back up the stack. |
| 391 | * |
| 392 | * Return: negative errno if an error occurs, 0 if submission was successful. |
| 393 | */ |
| 394 | int bdev_read_page(struct block_device *bdev, sector_t sector, |
| 395 | struct page *page) |
| 396 | { |
| 397 | const struct block_device_operations *ops = bdev->bd_disk->fops; |
| 398 | int result = -EOPNOTSUPP; |
| 399 | |
| 400 | if (!ops->rw_page || bdev_get_integrity(bdev)) |
| 401 | return result; |
| 402 | |
| 403 | result = blk_queue_enter(bdev->bd_queue, false); |
| 404 | if (result) |
| 405 | return result; |
| 406 | result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, READ); |
| 407 | blk_queue_exit(bdev->bd_queue); |
| 408 | return result; |
| 409 | } |
| 410 | EXPORT_SYMBOL_GPL(bdev_read_page); |
| 411 | |
| 412 | /** |
| 413 | * bdev_write_page() - Start writing a page to a block device |
| 414 | * @bdev: The device to write the page to |
| 415 | * @sector: The offset on the device to write the page to (need not be aligned) |
| 416 | * @page: The page to write |
| 417 | * @wbc: The writeback_control for the write |
| 418 | * |
| 419 | * On entry, the page should be locked and not currently under writeback. |
| 420 | * On exit, if the write started successfully, the page will be unlocked and |
| 421 | * under writeback. If the write failed already (eg the driver failed to |
| 422 | * queue the page to the device), the page will still be locked. If the |
| 423 | * caller is a ->writepage implementation, it will need to unlock the page. |
| 424 | * |
| 425 | * Errors returned by this function are usually "soft", eg out of memory, or |
| 426 | * queue full; callers should try a different route to write this page rather |
| 427 | * than propagate an error back up the stack. |
| 428 | * |
| 429 | * Return: negative errno if an error occurs, 0 if submission was successful. |
| 430 | */ |
| 431 | int bdev_write_page(struct block_device *bdev, sector_t sector, |
| 432 | struct page *page, struct writeback_control *wbc) |
| 433 | { |
| 434 | int result; |
| 435 | int rw = (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : WRITE; |
| 436 | const struct block_device_operations *ops = bdev->bd_disk->fops; |
| 437 | |
| 438 | if (!ops->rw_page || bdev_get_integrity(bdev)) |
| 439 | return -EOPNOTSUPP; |
| 440 | result = blk_queue_enter(bdev->bd_queue, false); |
| 441 | if (result) |
| 442 | return result; |
| 443 | |
| 444 | set_page_writeback(page); |
| 445 | result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, rw); |
| 446 | if (result) |
| 447 | end_page_writeback(page); |
| 448 | else |
| 449 | unlock_page(page); |
| 450 | blk_queue_exit(bdev->bd_queue); |
| 451 | return result; |
| 452 | } |
| 453 | EXPORT_SYMBOL_GPL(bdev_write_page); |
| 454 | |
| 455 | /** |
| 456 | * bdev_direct_access() - Get the address for directly-accessibly memory |
| 457 | * @bdev: The device containing the memory |
| 458 | * @dax: control and output parameters for ->direct_access |
| 459 | * |
| 460 | * If a block device is made up of directly addressable memory, this function |
| 461 | * will tell the caller the PFN and the address of the memory. The address |
| 462 | * may be directly dereferenced within the kernel without the need to call |
| 463 | * ioremap(), kmap() or similar. The PFN is suitable for inserting into |
| 464 | * page tables. |
| 465 | * |
| 466 | * Return: negative errno if an error occurs, otherwise the number of bytes |
| 467 | * accessible at this address. |
| 468 | */ |
| 469 | long bdev_direct_access(struct block_device *bdev, struct blk_dax_ctl *dax) |
| 470 | { |
| 471 | sector_t sector = dax->sector; |
| 472 | long avail, size = dax->size; |
| 473 | const struct block_device_operations *ops = bdev->bd_disk->fops; |
| 474 | |
| 475 | /* |
| 476 | * The device driver is allowed to sleep, in order to make the |
| 477 | * memory directly accessible. |
| 478 | */ |
| 479 | might_sleep(); |
| 480 | |
| 481 | if (size < 0) |
| 482 | return size; |
| 483 | if (!ops->direct_access) |
| 484 | return -EOPNOTSUPP; |
| 485 | if ((sector + DIV_ROUND_UP(size, 512)) > |
| 486 | part_nr_sects_read(bdev->bd_part)) |
| 487 | return -ERANGE; |
| 488 | sector += get_start_sect(bdev); |
| 489 | if (sector % (PAGE_SIZE / 512)) |
| 490 | return -EINVAL; |
| 491 | avail = ops->direct_access(bdev, sector, &dax->addr, &dax->pfn); |
| 492 | if (!avail) |
| 493 | return -ERANGE; |
| 494 | if (avail > 0 && avail & ~PAGE_MASK) |
| 495 | return -ENXIO; |
| 496 | return min(avail, size); |
| 497 | } |
| 498 | EXPORT_SYMBOL_GPL(bdev_direct_access); |
| 499 | |
| 500 | /* |
| 501 | * pseudo-fs |
| 502 | */ |
| 503 | |
| 504 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); |
| 505 | static struct kmem_cache * bdev_cachep __read_mostly; |
| 506 | |
| 507 | static struct inode *bdev_alloc_inode(struct super_block *sb) |
| 508 | { |
| 509 | struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL); |
| 510 | if (!ei) |
| 511 | return NULL; |
| 512 | return &ei->vfs_inode; |
| 513 | } |
| 514 | |
| 515 | static void bdev_i_callback(struct rcu_head *head) |
| 516 | { |
| 517 | struct inode *inode = container_of(head, struct inode, i_rcu); |
| 518 | struct bdev_inode *bdi = BDEV_I(inode); |
| 519 | |
| 520 | kmem_cache_free(bdev_cachep, bdi); |
| 521 | } |
| 522 | |
| 523 | static void bdev_destroy_inode(struct inode *inode) |
| 524 | { |
| 525 | call_rcu(&inode->i_rcu, bdev_i_callback); |
| 526 | } |
| 527 | |
| 528 | static void init_once(void *foo) |
| 529 | { |
| 530 | struct bdev_inode *ei = (struct bdev_inode *) foo; |
| 531 | struct block_device *bdev = &ei->bdev; |
| 532 | |
| 533 | memset(bdev, 0, sizeof(*bdev)); |
| 534 | mutex_init(&bdev->bd_mutex); |
| 535 | INIT_LIST_HEAD(&bdev->bd_inodes); |
| 536 | INIT_LIST_HEAD(&bdev->bd_list); |
| 537 | #ifdef CONFIG_SYSFS |
| 538 | INIT_LIST_HEAD(&bdev->bd_holder_disks); |
| 539 | #endif |
| 540 | inode_init_once(&ei->vfs_inode); |
| 541 | /* Initialize mutex for freeze. */ |
| 542 | mutex_init(&bdev->bd_fsfreeze_mutex); |
| 543 | } |
| 544 | |
| 545 | static inline void __bd_forget(struct inode *inode) |
| 546 | { |
| 547 | list_del_init(&inode->i_devices); |
| 548 | inode->i_bdev = NULL; |
| 549 | inode->i_mapping = &inode->i_data; |
| 550 | } |
| 551 | |
| 552 | static void bdev_evict_inode(struct inode *inode) |
| 553 | { |
| 554 | struct block_device *bdev = &BDEV_I(inode)->bdev; |
| 555 | struct list_head *p; |
| 556 | truncate_inode_pages_final(&inode->i_data); |
| 557 | invalidate_inode_buffers(inode); /* is it needed here? */ |
| 558 | clear_inode(inode); |
| 559 | spin_lock(&bdev_lock); |
| 560 | while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) { |
| 561 | __bd_forget(list_entry(p, struct inode, i_devices)); |
| 562 | } |
| 563 | list_del_init(&bdev->bd_list); |
| 564 | spin_unlock(&bdev_lock); |
| 565 | } |
| 566 | |
| 567 | static const struct super_operations bdev_sops = { |
| 568 | .statfs = simple_statfs, |
| 569 | .alloc_inode = bdev_alloc_inode, |
| 570 | .destroy_inode = bdev_destroy_inode, |
| 571 | .drop_inode = generic_delete_inode, |
| 572 | .evict_inode = bdev_evict_inode, |
| 573 | }; |
| 574 | |
| 575 | static struct dentry *bd_mount(struct file_system_type *fs_type, |
| 576 | int flags, const char *dev_name, void *data) |
| 577 | { |
| 578 | return mount_pseudo(fs_type, "bdev:", &bdev_sops, NULL, BDEVFS_MAGIC); |
| 579 | } |
| 580 | |
| 581 | static struct file_system_type bd_type = { |
| 582 | .name = "bdev", |
| 583 | .mount = bd_mount, |
| 584 | .kill_sb = kill_anon_super, |
| 585 | }; |
| 586 | |
| 587 | struct super_block *blockdev_superblock __read_mostly; |
| 588 | EXPORT_SYMBOL_GPL(blockdev_superblock); |
| 589 | |
| 590 | void __init bdev_cache_init(void) |
| 591 | { |
| 592 | int err; |
| 593 | static struct vfsmount *bd_mnt; |
| 594 | |
| 595 | bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), |
| 596 | 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| |
| 597 | SLAB_MEM_SPREAD|SLAB_ACCOUNT|SLAB_PANIC), |
| 598 | init_once); |
| 599 | err = register_filesystem(&bd_type); |
| 600 | if (err) |
| 601 | panic("Cannot register bdev pseudo-fs"); |
| 602 | bd_mnt = kern_mount(&bd_type); |
| 603 | if (IS_ERR(bd_mnt)) |
| 604 | panic("Cannot create bdev pseudo-fs"); |
| 605 | blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ |
| 606 | } |
| 607 | |
| 608 | /* |
| 609 | * Most likely _very_ bad one - but then it's hardly critical for small |
| 610 | * /dev and can be fixed when somebody will need really large one. |
| 611 | * Keep in mind that it will be fed through icache hash function too. |
| 612 | */ |
| 613 | static inline unsigned long hash(dev_t dev) |
| 614 | { |
| 615 | return MAJOR(dev)+MINOR(dev); |
| 616 | } |
| 617 | |
| 618 | static int bdev_test(struct inode *inode, void *data) |
| 619 | { |
| 620 | return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data; |
| 621 | } |
| 622 | |
| 623 | static int bdev_set(struct inode *inode, void *data) |
| 624 | { |
| 625 | BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data; |
| 626 | return 0; |
| 627 | } |
| 628 | |
| 629 | static LIST_HEAD(all_bdevs); |
| 630 | |
| 631 | struct block_device *bdget(dev_t dev) |
| 632 | { |
| 633 | struct block_device *bdev; |
| 634 | struct inode *inode; |
| 635 | |
| 636 | inode = iget5_locked(blockdev_superblock, hash(dev), |
| 637 | bdev_test, bdev_set, &dev); |
| 638 | |
| 639 | if (!inode) |
| 640 | return NULL; |
| 641 | |
| 642 | bdev = &BDEV_I(inode)->bdev; |
| 643 | |
| 644 | if (inode->i_state & I_NEW) { |
| 645 | bdev->bd_contains = NULL; |
| 646 | bdev->bd_super = NULL; |
| 647 | bdev->bd_inode = inode; |
| 648 | bdev->bd_block_size = (1 << inode->i_blkbits); |
| 649 | bdev->bd_part_count = 0; |
| 650 | bdev->bd_invalidated = 0; |
| 651 | inode->i_mode = S_IFBLK; |
| 652 | inode->i_rdev = dev; |
| 653 | inode->i_bdev = bdev; |
| 654 | inode->i_data.a_ops = &def_blk_aops; |
| 655 | mapping_set_gfp_mask(&inode->i_data, GFP_USER); |
| 656 | spin_lock(&bdev_lock); |
| 657 | list_add(&bdev->bd_list, &all_bdevs); |
| 658 | spin_unlock(&bdev_lock); |
| 659 | unlock_new_inode(inode); |
| 660 | } |
| 661 | return bdev; |
| 662 | } |
| 663 | |
| 664 | EXPORT_SYMBOL(bdget); |
| 665 | |
| 666 | /** |
| 667 | * bdgrab -- Grab a reference to an already referenced block device |
| 668 | * @bdev: Block device to grab a reference to. |
| 669 | */ |
| 670 | struct block_device *bdgrab(struct block_device *bdev) |
| 671 | { |
| 672 | ihold(bdev->bd_inode); |
| 673 | return bdev; |
| 674 | } |
| 675 | EXPORT_SYMBOL(bdgrab); |
| 676 | |
| 677 | long nr_blockdev_pages(void) |
| 678 | { |
| 679 | struct block_device *bdev; |
| 680 | long ret = 0; |
| 681 | spin_lock(&bdev_lock); |
| 682 | list_for_each_entry(bdev, &all_bdevs, bd_list) { |
| 683 | ret += bdev->bd_inode->i_mapping->nrpages; |
| 684 | } |
| 685 | spin_unlock(&bdev_lock); |
| 686 | return ret; |
| 687 | } |
| 688 | |
| 689 | void bdput(struct block_device *bdev) |
| 690 | { |
| 691 | iput(bdev->bd_inode); |
| 692 | } |
| 693 | |
| 694 | EXPORT_SYMBOL(bdput); |
| 695 | |
| 696 | static struct block_device *bd_acquire(struct inode *inode) |
| 697 | { |
| 698 | struct block_device *bdev; |
| 699 | |
| 700 | spin_lock(&bdev_lock); |
| 701 | bdev = inode->i_bdev; |
| 702 | if (bdev) { |
| 703 | bdgrab(bdev); |
| 704 | spin_unlock(&bdev_lock); |
| 705 | return bdev; |
| 706 | } |
| 707 | spin_unlock(&bdev_lock); |
| 708 | |
| 709 | bdev = bdget(inode->i_rdev); |
| 710 | if (bdev) { |
| 711 | spin_lock(&bdev_lock); |
| 712 | if (!inode->i_bdev) { |
| 713 | /* |
| 714 | * We take an additional reference to bd_inode, |
| 715 | * and it's released in clear_inode() of inode. |
| 716 | * So, we can access it via ->i_mapping always |
| 717 | * without igrab(). |
| 718 | */ |
| 719 | bdgrab(bdev); |
| 720 | inode->i_bdev = bdev; |
| 721 | inode->i_mapping = bdev->bd_inode->i_mapping; |
| 722 | list_add(&inode->i_devices, &bdev->bd_inodes); |
| 723 | } |
| 724 | spin_unlock(&bdev_lock); |
| 725 | } |
| 726 | return bdev; |
| 727 | } |
| 728 | |
| 729 | /* Call when you free inode */ |
| 730 | |
| 731 | void bd_forget(struct inode *inode) |
| 732 | { |
| 733 | struct block_device *bdev = NULL; |
| 734 | |
| 735 | spin_lock(&bdev_lock); |
| 736 | if (!sb_is_blkdev_sb(inode->i_sb)) |
| 737 | bdev = inode->i_bdev; |
| 738 | __bd_forget(inode); |
| 739 | spin_unlock(&bdev_lock); |
| 740 | |
| 741 | if (bdev) |
| 742 | bdput(bdev); |
| 743 | } |
| 744 | |
| 745 | /** |
| 746 | * bd_may_claim - test whether a block device can be claimed |
| 747 | * @bdev: block device of interest |
| 748 | * @whole: whole block device containing @bdev, may equal @bdev |
| 749 | * @holder: holder trying to claim @bdev |
| 750 | * |
| 751 | * Test whether @bdev can be claimed by @holder. |
| 752 | * |
| 753 | * CONTEXT: |
| 754 | * spin_lock(&bdev_lock). |
| 755 | * |
| 756 | * RETURNS: |
| 757 | * %true if @bdev can be claimed, %false otherwise. |
| 758 | */ |
| 759 | static bool bd_may_claim(struct block_device *bdev, struct block_device *whole, |
| 760 | void *holder) |
| 761 | { |
| 762 | if (bdev->bd_holder == holder) |
| 763 | return true; /* already a holder */ |
| 764 | else if (bdev->bd_holder != NULL) |
| 765 | return false; /* held by someone else */ |
| 766 | else if (bdev->bd_contains == bdev) |
| 767 | return true; /* is a whole device which isn't held */ |
| 768 | |
| 769 | else if (whole->bd_holder == bd_may_claim) |
| 770 | return true; /* is a partition of a device that is being partitioned */ |
| 771 | else if (whole->bd_holder != NULL) |
| 772 | return false; /* is a partition of a held device */ |
| 773 | else |
| 774 | return true; /* is a partition of an un-held device */ |
| 775 | } |
| 776 | |
| 777 | /** |
| 778 | * bd_prepare_to_claim - prepare to claim a block device |
| 779 | * @bdev: block device of interest |
| 780 | * @whole: the whole device containing @bdev, may equal @bdev |
| 781 | * @holder: holder trying to claim @bdev |
| 782 | * |
| 783 | * Prepare to claim @bdev. This function fails if @bdev is already |
| 784 | * claimed by another holder and waits if another claiming is in |
| 785 | * progress. This function doesn't actually claim. On successful |
| 786 | * return, the caller has ownership of bd_claiming and bd_holder[s]. |
| 787 | * |
| 788 | * CONTEXT: |
| 789 | * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab |
| 790 | * it multiple times. |
| 791 | * |
| 792 | * RETURNS: |
| 793 | * 0 if @bdev can be claimed, -EBUSY otherwise. |
| 794 | */ |
| 795 | static int bd_prepare_to_claim(struct block_device *bdev, |
| 796 | struct block_device *whole, void *holder) |
| 797 | { |
| 798 | retry: |
| 799 | /* if someone else claimed, fail */ |
| 800 | if (!bd_may_claim(bdev, whole, holder)) |
| 801 | return -EBUSY; |
| 802 | |
| 803 | /* if claiming is already in progress, wait for it to finish */ |
| 804 | if (whole->bd_claiming) { |
| 805 | wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0); |
| 806 | DEFINE_WAIT(wait); |
| 807 | |
| 808 | prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); |
| 809 | spin_unlock(&bdev_lock); |
| 810 | schedule(); |
| 811 | finish_wait(wq, &wait); |
| 812 | spin_lock(&bdev_lock); |
| 813 | goto retry; |
| 814 | } |
| 815 | |
| 816 | /* yay, all mine */ |
| 817 | return 0; |
| 818 | } |
| 819 | |
| 820 | /** |
| 821 | * bd_start_claiming - start claiming a block device |
| 822 | * @bdev: block device of interest |
| 823 | * @holder: holder trying to claim @bdev |
| 824 | * |
| 825 | * @bdev is about to be opened exclusively. Check @bdev can be opened |
| 826 | * exclusively and mark that an exclusive open is in progress. Each |
| 827 | * successful call to this function must be matched with a call to |
| 828 | * either bd_finish_claiming() or bd_abort_claiming() (which do not |
| 829 | * fail). |
| 830 | * |
| 831 | * This function is used to gain exclusive access to the block device |
| 832 | * without actually causing other exclusive open attempts to fail. It |
| 833 | * should be used when the open sequence itself requires exclusive |
| 834 | * access but may subsequently fail. |
| 835 | * |
| 836 | * CONTEXT: |
| 837 | * Might sleep. |
| 838 | * |
| 839 | * RETURNS: |
| 840 | * Pointer to the block device containing @bdev on success, ERR_PTR() |
| 841 | * value on failure. |
| 842 | */ |
| 843 | static struct block_device *bd_start_claiming(struct block_device *bdev, |
| 844 | void *holder) |
| 845 | { |
| 846 | struct gendisk *disk; |
| 847 | struct block_device *whole; |
| 848 | int partno, err; |
| 849 | |
| 850 | might_sleep(); |
| 851 | |
| 852 | /* |
| 853 | * @bdev might not have been initialized properly yet, look up |
| 854 | * and grab the outer block device the hard way. |
| 855 | */ |
| 856 | disk = get_gendisk(bdev->bd_dev, &partno); |
| 857 | if (!disk) |
| 858 | return ERR_PTR(-ENXIO); |
| 859 | |
| 860 | /* |
| 861 | * Normally, @bdev should equal what's returned from bdget_disk() |
| 862 | * if partno is 0; however, some drivers (floppy) use multiple |
| 863 | * bdev's for the same physical device and @bdev may be one of the |
| 864 | * aliases. Keep @bdev if partno is 0. This means claimer |
| 865 | * tracking is broken for those devices but it has always been that |
| 866 | * way. |
| 867 | */ |
| 868 | if (partno) |
| 869 | whole = bdget_disk(disk, 0); |
| 870 | else |
| 871 | whole = bdgrab(bdev); |
| 872 | |
| 873 | module_put(disk->fops->owner); |
| 874 | put_disk(disk); |
| 875 | if (!whole) |
| 876 | return ERR_PTR(-ENOMEM); |
| 877 | |
| 878 | /* prepare to claim, if successful, mark claiming in progress */ |
| 879 | spin_lock(&bdev_lock); |
| 880 | |
| 881 | err = bd_prepare_to_claim(bdev, whole, holder); |
| 882 | if (err == 0) { |
| 883 | whole->bd_claiming = holder; |
| 884 | spin_unlock(&bdev_lock); |
| 885 | return whole; |
| 886 | } else { |
| 887 | spin_unlock(&bdev_lock); |
| 888 | bdput(whole); |
| 889 | return ERR_PTR(err); |
| 890 | } |
| 891 | } |
| 892 | |
| 893 | #ifdef CONFIG_SYSFS |
| 894 | struct bd_holder_disk { |
| 895 | struct list_head list; |
| 896 | struct gendisk *disk; |
| 897 | int refcnt; |
| 898 | }; |
| 899 | |
| 900 | static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev, |
| 901 | struct gendisk *disk) |
| 902 | { |
| 903 | struct bd_holder_disk *holder; |
| 904 | |
| 905 | list_for_each_entry(holder, &bdev->bd_holder_disks, list) |
| 906 | if (holder->disk == disk) |
| 907 | return holder; |
| 908 | return NULL; |
| 909 | } |
| 910 | |
| 911 | static int add_symlink(struct kobject *from, struct kobject *to) |
| 912 | { |
| 913 | return sysfs_create_link(from, to, kobject_name(to)); |
| 914 | } |
| 915 | |
| 916 | static void del_symlink(struct kobject *from, struct kobject *to) |
| 917 | { |
| 918 | sysfs_remove_link(from, kobject_name(to)); |
| 919 | } |
| 920 | |
| 921 | /** |
| 922 | * bd_link_disk_holder - create symlinks between holding disk and slave bdev |
| 923 | * @bdev: the claimed slave bdev |
| 924 | * @disk: the holding disk |
| 925 | * |
| 926 | * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT. |
| 927 | * |
| 928 | * This functions creates the following sysfs symlinks. |
| 929 | * |
| 930 | * - from "slaves" directory of the holder @disk to the claimed @bdev |
| 931 | * - from "holders" directory of the @bdev to the holder @disk |
| 932 | * |
| 933 | * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is |
| 934 | * passed to bd_link_disk_holder(), then: |
| 935 | * |
| 936 | * /sys/block/dm-0/slaves/sda --> /sys/block/sda |
| 937 | * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0 |
| 938 | * |
| 939 | * The caller must have claimed @bdev before calling this function and |
| 940 | * ensure that both @bdev and @disk are valid during the creation and |
| 941 | * lifetime of these symlinks. |
| 942 | * |
| 943 | * CONTEXT: |
| 944 | * Might sleep. |
| 945 | * |
| 946 | * RETURNS: |
| 947 | * 0 on success, -errno on failure. |
| 948 | */ |
| 949 | int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk) |
| 950 | { |
| 951 | struct bd_holder_disk *holder; |
| 952 | int ret = 0; |
| 953 | |
| 954 | mutex_lock(&bdev->bd_mutex); |
| 955 | |
| 956 | WARN_ON_ONCE(!bdev->bd_holder); |
| 957 | |
| 958 | /* FIXME: remove the following once add_disk() handles errors */ |
| 959 | if (WARN_ON(!disk->slave_dir || !bdev->bd_part->holder_dir)) |
| 960 | goto out_unlock; |
| 961 | |
| 962 | holder = bd_find_holder_disk(bdev, disk); |
| 963 | if (holder) { |
| 964 | holder->refcnt++; |
| 965 | goto out_unlock; |
| 966 | } |
| 967 | |
| 968 | holder = kzalloc(sizeof(*holder), GFP_KERNEL); |
| 969 | if (!holder) { |
| 970 | ret = -ENOMEM; |
| 971 | goto out_unlock; |
| 972 | } |
| 973 | |
| 974 | INIT_LIST_HEAD(&holder->list); |
| 975 | holder->disk = disk; |
| 976 | holder->refcnt = 1; |
| 977 | |
| 978 | ret = add_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); |
| 979 | if (ret) |
| 980 | goto out_free; |
| 981 | |
| 982 | ret = add_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj); |
| 983 | if (ret) |
| 984 | goto out_del; |
| 985 | /* |
| 986 | * bdev could be deleted beneath us which would implicitly destroy |
| 987 | * the holder directory. Hold on to it. |
| 988 | */ |
| 989 | kobject_get(bdev->bd_part->holder_dir); |
| 990 | |
| 991 | list_add(&holder->list, &bdev->bd_holder_disks); |
| 992 | goto out_unlock; |
| 993 | |
| 994 | out_del: |
| 995 | del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); |
| 996 | out_free: |
| 997 | kfree(holder); |
| 998 | out_unlock: |
| 999 | mutex_unlock(&bdev->bd_mutex); |
| 1000 | return ret; |
| 1001 | } |
| 1002 | EXPORT_SYMBOL_GPL(bd_link_disk_holder); |
| 1003 | |
| 1004 | /** |
| 1005 | * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder() |
| 1006 | * @bdev: the calimed slave bdev |
| 1007 | * @disk: the holding disk |
| 1008 | * |
| 1009 | * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT. |
| 1010 | * |
| 1011 | * CONTEXT: |
| 1012 | * Might sleep. |
| 1013 | */ |
| 1014 | void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk) |
| 1015 | { |
| 1016 | struct bd_holder_disk *holder; |
| 1017 | |
| 1018 | mutex_lock(&bdev->bd_mutex); |
| 1019 | |
| 1020 | holder = bd_find_holder_disk(bdev, disk); |
| 1021 | |
| 1022 | if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) { |
| 1023 | del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); |
| 1024 | del_symlink(bdev->bd_part->holder_dir, |
| 1025 | &disk_to_dev(disk)->kobj); |
| 1026 | kobject_put(bdev->bd_part->holder_dir); |
| 1027 | list_del_init(&holder->list); |
| 1028 | kfree(holder); |
| 1029 | } |
| 1030 | |
| 1031 | mutex_unlock(&bdev->bd_mutex); |
| 1032 | } |
| 1033 | EXPORT_SYMBOL_GPL(bd_unlink_disk_holder); |
| 1034 | #endif |
| 1035 | |
| 1036 | /** |
| 1037 | * flush_disk - invalidates all buffer-cache entries on a disk |
| 1038 | * |
| 1039 | * @bdev: struct block device to be flushed |
| 1040 | * @kill_dirty: flag to guide handling of dirty inodes |
| 1041 | * |
| 1042 | * Invalidates all buffer-cache entries on a disk. It should be called |
| 1043 | * when a disk has been changed -- either by a media change or online |
| 1044 | * resize. |
| 1045 | */ |
| 1046 | static void flush_disk(struct block_device *bdev, bool kill_dirty) |
| 1047 | { |
| 1048 | if (__invalidate_device(bdev, kill_dirty)) { |
| 1049 | printk(KERN_WARNING "VFS: busy inodes on changed media or " |
| 1050 | "resized disk %s\n", |
| 1051 | bdev->bd_disk ? bdev->bd_disk->disk_name : ""); |
| 1052 | } |
| 1053 | |
| 1054 | if (!bdev->bd_disk) |
| 1055 | return; |
| 1056 | if (disk_part_scan_enabled(bdev->bd_disk)) |
| 1057 | bdev->bd_invalidated = 1; |
| 1058 | } |
| 1059 | |
| 1060 | /** |
| 1061 | * check_disk_size_change - checks for disk size change and adjusts bdev size. |
| 1062 | * @disk: struct gendisk to check |
| 1063 | * @bdev: struct bdev to adjust. |
| 1064 | * |
| 1065 | * This routine checks to see if the bdev size does not match the disk size |
| 1066 | * and adjusts it if it differs. |
| 1067 | */ |
| 1068 | void check_disk_size_change(struct gendisk *disk, struct block_device *bdev) |
| 1069 | { |
| 1070 | loff_t disk_size, bdev_size; |
| 1071 | |
| 1072 | disk_size = (loff_t)get_capacity(disk) << 9; |
| 1073 | bdev_size = i_size_read(bdev->bd_inode); |
| 1074 | if (disk_size != bdev_size) { |
| 1075 | printk(KERN_INFO |
| 1076 | "%s: detected capacity change from %lld to %lld\n", |
| 1077 | disk->disk_name, bdev_size, disk_size); |
| 1078 | i_size_write(bdev->bd_inode, disk_size); |
| 1079 | flush_disk(bdev, false); |
| 1080 | } |
| 1081 | } |
| 1082 | EXPORT_SYMBOL(check_disk_size_change); |
| 1083 | |
| 1084 | /** |
| 1085 | * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back |
| 1086 | * @disk: struct gendisk to be revalidated |
| 1087 | * |
| 1088 | * This routine is a wrapper for lower-level driver's revalidate_disk |
| 1089 | * call-backs. It is used to do common pre and post operations needed |
| 1090 | * for all revalidate_disk operations. |
| 1091 | */ |
| 1092 | int revalidate_disk(struct gendisk *disk) |
| 1093 | { |
| 1094 | struct block_device *bdev; |
| 1095 | int ret = 0; |
| 1096 | |
| 1097 | if (disk->fops->revalidate_disk) |
| 1098 | ret = disk->fops->revalidate_disk(disk); |
| 1099 | blk_integrity_revalidate(disk); |
| 1100 | bdev = bdget_disk(disk, 0); |
| 1101 | if (!bdev) |
| 1102 | return ret; |
| 1103 | |
| 1104 | mutex_lock(&bdev->bd_mutex); |
| 1105 | check_disk_size_change(disk, bdev); |
| 1106 | bdev->bd_invalidated = 0; |
| 1107 | mutex_unlock(&bdev->bd_mutex); |
| 1108 | bdput(bdev); |
| 1109 | return ret; |
| 1110 | } |
| 1111 | EXPORT_SYMBOL(revalidate_disk); |
| 1112 | |
| 1113 | /* |
| 1114 | * This routine checks whether a removable media has been changed, |
| 1115 | * and invalidates all buffer-cache-entries in that case. This |
| 1116 | * is a relatively slow routine, so we have to try to minimize using |
| 1117 | * it. Thus it is called only upon a 'mount' or 'open'. This |
| 1118 | * is the best way of combining speed and utility, I think. |
| 1119 | * People changing diskettes in the middle of an operation deserve |
| 1120 | * to lose :-) |
| 1121 | */ |
| 1122 | int check_disk_change(struct block_device *bdev) |
| 1123 | { |
| 1124 | struct gendisk *disk = bdev->bd_disk; |
| 1125 | const struct block_device_operations *bdops = disk->fops; |
| 1126 | unsigned int events; |
| 1127 | |
| 1128 | events = disk_clear_events(disk, DISK_EVENT_MEDIA_CHANGE | |
| 1129 | DISK_EVENT_EJECT_REQUEST); |
| 1130 | if (!(events & DISK_EVENT_MEDIA_CHANGE)) |
| 1131 | return 0; |
| 1132 | |
| 1133 | flush_disk(bdev, true); |
| 1134 | if (bdops->revalidate_disk) |
| 1135 | bdops->revalidate_disk(bdev->bd_disk); |
| 1136 | return 1; |
| 1137 | } |
| 1138 | |
| 1139 | EXPORT_SYMBOL(check_disk_change); |
| 1140 | |
| 1141 | void bd_set_size(struct block_device *bdev, loff_t size) |
| 1142 | { |
| 1143 | unsigned bsize = bdev_logical_block_size(bdev); |
| 1144 | |
| 1145 | inode_lock(bdev->bd_inode); |
| 1146 | i_size_write(bdev->bd_inode, size); |
| 1147 | inode_unlock(bdev->bd_inode); |
| 1148 | while (bsize < PAGE_CACHE_SIZE) { |
| 1149 | if (size & bsize) |
| 1150 | break; |
| 1151 | bsize <<= 1; |
| 1152 | } |
| 1153 | bdev->bd_block_size = bsize; |
| 1154 | bdev->bd_inode->i_blkbits = blksize_bits(bsize); |
| 1155 | } |
| 1156 | EXPORT_SYMBOL(bd_set_size); |
| 1157 | |
| 1158 | static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part); |
| 1159 | |
| 1160 | /* |
| 1161 | * bd_mutex locking: |
| 1162 | * |
| 1163 | * mutex_lock(part->bd_mutex) |
| 1164 | * mutex_lock_nested(whole->bd_mutex, 1) |
| 1165 | */ |
| 1166 | |
| 1167 | static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) |
| 1168 | { |
| 1169 | struct gendisk *disk; |
| 1170 | struct module *owner; |
| 1171 | int ret; |
| 1172 | int partno; |
| 1173 | int perm = 0; |
| 1174 | |
| 1175 | if (mode & FMODE_READ) |
| 1176 | perm |= MAY_READ; |
| 1177 | if (mode & FMODE_WRITE) |
| 1178 | perm |= MAY_WRITE; |
| 1179 | /* |
| 1180 | * hooks: /n/, see "layering violations". |
| 1181 | */ |
| 1182 | if (!for_part) { |
| 1183 | ret = devcgroup_inode_permission(bdev->bd_inode, perm); |
| 1184 | if (ret != 0) { |
| 1185 | bdput(bdev); |
| 1186 | return ret; |
| 1187 | } |
| 1188 | } |
| 1189 | |
| 1190 | restart: |
| 1191 | |
| 1192 | ret = -ENXIO; |
| 1193 | disk = get_gendisk(bdev->bd_dev, &partno); |
| 1194 | if (!disk) |
| 1195 | goto out; |
| 1196 | owner = disk->fops->owner; |
| 1197 | |
| 1198 | disk_block_events(disk); |
| 1199 | mutex_lock_nested(&bdev->bd_mutex, for_part); |
| 1200 | if (!bdev->bd_openers) { |
| 1201 | bdev->bd_disk = disk; |
| 1202 | bdev->bd_queue = disk->queue; |
| 1203 | bdev->bd_contains = bdev; |
| 1204 | if (IS_ENABLED(CONFIG_BLK_DEV_DAX) && disk->fops->direct_access) |
| 1205 | bdev->bd_inode->i_flags = S_DAX; |
| 1206 | else |
| 1207 | bdev->bd_inode->i_flags = 0; |
| 1208 | |
| 1209 | if (!partno) { |
| 1210 | ret = -ENXIO; |
| 1211 | bdev->bd_part = disk_get_part(disk, partno); |
| 1212 | if (!bdev->bd_part) |
| 1213 | goto out_clear; |
| 1214 | |
| 1215 | ret = 0; |
| 1216 | if (disk->fops->open) { |
| 1217 | ret = disk->fops->open(bdev, mode); |
| 1218 | if (ret == -ERESTARTSYS) { |
| 1219 | /* Lost a race with 'disk' being |
| 1220 | * deleted, try again. |
| 1221 | * See md.c |
| 1222 | */ |
| 1223 | disk_put_part(bdev->bd_part); |
| 1224 | bdev->bd_part = NULL; |
| 1225 | bdev->bd_disk = NULL; |
| 1226 | bdev->bd_queue = NULL; |
| 1227 | mutex_unlock(&bdev->bd_mutex); |
| 1228 | disk_unblock_events(disk); |
| 1229 | put_disk(disk); |
| 1230 | module_put(owner); |
| 1231 | goto restart; |
| 1232 | } |
| 1233 | } |
| 1234 | |
| 1235 | if (!ret) { |
| 1236 | bd_set_size(bdev,(loff_t)get_capacity(disk)<<9); |
| 1237 | if (!blkdev_dax_capable(bdev)) |
| 1238 | bdev->bd_inode->i_flags &= ~S_DAX; |
| 1239 | } |
| 1240 | |
| 1241 | /* |
| 1242 | * If the device is invalidated, rescan partition |
| 1243 | * if open succeeded or failed with -ENOMEDIUM. |
| 1244 | * The latter is necessary to prevent ghost |
| 1245 | * partitions on a removed medium. |
| 1246 | */ |
| 1247 | if (bdev->bd_invalidated) { |
| 1248 | if (!ret) |
| 1249 | rescan_partitions(disk, bdev); |
| 1250 | else if (ret == -ENOMEDIUM) |
| 1251 | invalidate_partitions(disk, bdev); |
| 1252 | } |
| 1253 | |
| 1254 | if (ret) |
| 1255 | goto out_clear; |
| 1256 | } else { |
| 1257 | struct block_device *whole; |
| 1258 | whole = bdget_disk(disk, 0); |
| 1259 | ret = -ENOMEM; |
| 1260 | if (!whole) |
| 1261 | goto out_clear; |
| 1262 | BUG_ON(for_part); |
| 1263 | ret = __blkdev_get(whole, mode, 1); |
| 1264 | if (ret) |
| 1265 | goto out_clear; |
| 1266 | bdev->bd_contains = whole; |
| 1267 | bdev->bd_part = disk_get_part(disk, partno); |
| 1268 | if (!(disk->flags & GENHD_FL_UP) || |
| 1269 | !bdev->bd_part || !bdev->bd_part->nr_sects) { |
| 1270 | ret = -ENXIO; |
| 1271 | goto out_clear; |
| 1272 | } |
| 1273 | bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9); |
| 1274 | if (!blkdev_dax_capable(bdev)) |
| 1275 | bdev->bd_inode->i_flags &= ~S_DAX; |
| 1276 | } |
| 1277 | } else { |
| 1278 | if (bdev->bd_contains == bdev) { |
| 1279 | ret = 0; |
| 1280 | if (bdev->bd_disk->fops->open) |
| 1281 | ret = bdev->bd_disk->fops->open(bdev, mode); |
| 1282 | /* the same as first opener case, read comment there */ |
| 1283 | if (bdev->bd_invalidated) { |
| 1284 | if (!ret) |
| 1285 | rescan_partitions(bdev->bd_disk, bdev); |
| 1286 | else if (ret == -ENOMEDIUM) |
| 1287 | invalidate_partitions(bdev->bd_disk, bdev); |
| 1288 | } |
| 1289 | if (ret) |
| 1290 | goto out_unlock_bdev; |
| 1291 | } |
| 1292 | /* only one opener holds refs to the module and disk */ |
| 1293 | put_disk(disk); |
| 1294 | module_put(owner); |
| 1295 | } |
| 1296 | bdev->bd_openers++; |
| 1297 | if (for_part) |
| 1298 | bdev->bd_part_count++; |
| 1299 | mutex_unlock(&bdev->bd_mutex); |
| 1300 | disk_unblock_events(disk); |
| 1301 | return 0; |
| 1302 | |
| 1303 | out_clear: |
| 1304 | disk_put_part(bdev->bd_part); |
| 1305 | bdev->bd_disk = NULL; |
| 1306 | bdev->bd_part = NULL; |
| 1307 | bdev->bd_queue = NULL; |
| 1308 | if (bdev != bdev->bd_contains) |
| 1309 | __blkdev_put(bdev->bd_contains, mode, 1); |
| 1310 | bdev->bd_contains = NULL; |
| 1311 | out_unlock_bdev: |
| 1312 | mutex_unlock(&bdev->bd_mutex); |
| 1313 | disk_unblock_events(disk); |
| 1314 | put_disk(disk); |
| 1315 | module_put(owner); |
| 1316 | out: |
| 1317 | bdput(bdev); |
| 1318 | |
| 1319 | return ret; |
| 1320 | } |
| 1321 | |
| 1322 | /** |
| 1323 | * blkdev_get - open a block device |
| 1324 | * @bdev: block_device to open |
| 1325 | * @mode: FMODE_* mask |
| 1326 | * @holder: exclusive holder identifier |
| 1327 | * |
| 1328 | * Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is |
| 1329 | * open with exclusive access. Specifying %FMODE_EXCL with %NULL |
| 1330 | * @holder is invalid. Exclusive opens may nest for the same @holder. |
| 1331 | * |
| 1332 | * On success, the reference count of @bdev is unchanged. On failure, |
| 1333 | * @bdev is put. |
| 1334 | * |
| 1335 | * CONTEXT: |
| 1336 | * Might sleep. |
| 1337 | * |
| 1338 | * RETURNS: |
| 1339 | * 0 on success, -errno on failure. |
| 1340 | */ |
| 1341 | int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) |
| 1342 | { |
| 1343 | struct block_device *whole = NULL; |
| 1344 | int res; |
| 1345 | |
| 1346 | WARN_ON_ONCE((mode & FMODE_EXCL) && !holder); |
| 1347 | |
| 1348 | if ((mode & FMODE_EXCL) && holder) { |
| 1349 | whole = bd_start_claiming(bdev, holder); |
| 1350 | if (IS_ERR(whole)) { |
| 1351 | bdput(bdev); |
| 1352 | return PTR_ERR(whole); |
| 1353 | } |
| 1354 | } |
| 1355 | |
| 1356 | res = __blkdev_get(bdev, mode, 0); |
| 1357 | |
| 1358 | if (whole) { |
| 1359 | struct gendisk *disk = whole->bd_disk; |
| 1360 | |
| 1361 | /* finish claiming */ |
| 1362 | mutex_lock(&bdev->bd_mutex); |
| 1363 | spin_lock(&bdev_lock); |
| 1364 | |
| 1365 | if (!res) { |
| 1366 | BUG_ON(!bd_may_claim(bdev, whole, holder)); |
| 1367 | /* |
| 1368 | * Note that for a whole device bd_holders |
| 1369 | * will be incremented twice, and bd_holder |
| 1370 | * will be set to bd_may_claim before being |
| 1371 | * set to holder |
| 1372 | */ |
| 1373 | whole->bd_holders++; |
| 1374 | whole->bd_holder = bd_may_claim; |
| 1375 | bdev->bd_holders++; |
| 1376 | bdev->bd_holder = holder; |
| 1377 | } |
| 1378 | |
| 1379 | /* tell others that we're done */ |
| 1380 | BUG_ON(whole->bd_claiming != holder); |
| 1381 | whole->bd_claiming = NULL; |
| 1382 | wake_up_bit(&whole->bd_claiming, 0); |
| 1383 | |
| 1384 | spin_unlock(&bdev_lock); |
| 1385 | |
| 1386 | /* |
| 1387 | * Block event polling for write claims if requested. Any |
| 1388 | * write holder makes the write_holder state stick until |
| 1389 | * all are released. This is good enough and tracking |
| 1390 | * individual writeable reference is too fragile given the |
| 1391 | * way @mode is used in blkdev_get/put(). |
| 1392 | */ |
| 1393 | if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder && |
| 1394 | (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) { |
| 1395 | bdev->bd_write_holder = true; |
| 1396 | disk_block_events(disk); |
| 1397 | } |
| 1398 | |
| 1399 | mutex_unlock(&bdev->bd_mutex); |
| 1400 | bdput(whole); |
| 1401 | } |
| 1402 | |
| 1403 | return res; |
| 1404 | } |
| 1405 | EXPORT_SYMBOL(blkdev_get); |
| 1406 | |
| 1407 | /** |
| 1408 | * blkdev_get_by_path - open a block device by name |
| 1409 | * @path: path to the block device to open |
| 1410 | * @mode: FMODE_* mask |
| 1411 | * @holder: exclusive holder identifier |
| 1412 | * |
| 1413 | * Open the blockdevice described by the device file at @path. @mode |
| 1414 | * and @holder are identical to blkdev_get(). |
| 1415 | * |
| 1416 | * On success, the returned block_device has reference count of one. |
| 1417 | * |
| 1418 | * CONTEXT: |
| 1419 | * Might sleep. |
| 1420 | * |
| 1421 | * RETURNS: |
| 1422 | * Pointer to block_device on success, ERR_PTR(-errno) on failure. |
| 1423 | */ |
| 1424 | struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, |
| 1425 | void *holder) |
| 1426 | { |
| 1427 | struct block_device *bdev; |
| 1428 | int err; |
| 1429 | |
| 1430 | bdev = lookup_bdev(path); |
| 1431 | if (IS_ERR(bdev)) |
| 1432 | return bdev; |
| 1433 | |
| 1434 | err = blkdev_get(bdev, mode, holder); |
| 1435 | if (err) |
| 1436 | return ERR_PTR(err); |
| 1437 | |
| 1438 | if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) { |
| 1439 | blkdev_put(bdev, mode); |
| 1440 | return ERR_PTR(-EACCES); |
| 1441 | } |
| 1442 | |
| 1443 | return bdev; |
| 1444 | } |
| 1445 | EXPORT_SYMBOL(blkdev_get_by_path); |
| 1446 | |
| 1447 | /** |
| 1448 | * blkdev_get_by_dev - open a block device by device number |
| 1449 | * @dev: device number of block device to open |
| 1450 | * @mode: FMODE_* mask |
| 1451 | * @holder: exclusive holder identifier |
| 1452 | * |
| 1453 | * Open the blockdevice described by device number @dev. @mode and |
| 1454 | * @holder are identical to blkdev_get(). |
| 1455 | * |
| 1456 | * Use it ONLY if you really do not have anything better - i.e. when |
| 1457 | * you are behind a truly sucky interface and all you are given is a |
| 1458 | * device number. _Never_ to be used for internal purposes. If you |
| 1459 | * ever need it - reconsider your API. |
| 1460 | * |
| 1461 | * On success, the returned block_device has reference count of one. |
| 1462 | * |
| 1463 | * CONTEXT: |
| 1464 | * Might sleep. |
| 1465 | * |
| 1466 | * RETURNS: |
| 1467 | * Pointer to block_device on success, ERR_PTR(-errno) on failure. |
| 1468 | */ |
| 1469 | struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) |
| 1470 | { |
| 1471 | struct block_device *bdev; |
| 1472 | int err; |
| 1473 | |
| 1474 | bdev = bdget(dev); |
| 1475 | if (!bdev) |
| 1476 | return ERR_PTR(-ENOMEM); |
| 1477 | |
| 1478 | err = blkdev_get(bdev, mode, holder); |
| 1479 | if (err) |
| 1480 | return ERR_PTR(err); |
| 1481 | |
| 1482 | return bdev; |
| 1483 | } |
| 1484 | EXPORT_SYMBOL(blkdev_get_by_dev); |
| 1485 | |
| 1486 | static int blkdev_open(struct inode * inode, struct file * filp) |
| 1487 | { |
| 1488 | struct block_device *bdev; |
| 1489 | |
| 1490 | /* |
| 1491 | * Preserve backwards compatibility and allow large file access |
| 1492 | * even if userspace doesn't ask for it explicitly. Some mkfs |
| 1493 | * binary needs it. We might want to drop this workaround |
| 1494 | * during an unstable branch. |
| 1495 | */ |
| 1496 | filp->f_flags |= O_LARGEFILE; |
| 1497 | |
| 1498 | if (filp->f_flags & O_NDELAY) |
| 1499 | filp->f_mode |= FMODE_NDELAY; |
| 1500 | if (filp->f_flags & O_EXCL) |
| 1501 | filp->f_mode |= FMODE_EXCL; |
| 1502 | if ((filp->f_flags & O_ACCMODE) == 3) |
| 1503 | filp->f_mode |= FMODE_WRITE_IOCTL; |
| 1504 | |
| 1505 | bdev = bd_acquire(inode); |
| 1506 | if (bdev == NULL) |
| 1507 | return -ENOMEM; |
| 1508 | |
| 1509 | filp->f_mapping = bdev->bd_inode->i_mapping; |
| 1510 | |
| 1511 | return blkdev_get(bdev, filp->f_mode, filp); |
| 1512 | } |
| 1513 | |
| 1514 | static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) |
| 1515 | { |
| 1516 | struct gendisk *disk = bdev->bd_disk; |
| 1517 | struct block_device *victim = NULL; |
| 1518 | |
| 1519 | mutex_lock_nested(&bdev->bd_mutex, for_part); |
| 1520 | if (for_part) |
| 1521 | bdev->bd_part_count--; |
| 1522 | |
| 1523 | if (!--bdev->bd_openers) { |
| 1524 | WARN_ON_ONCE(bdev->bd_holders); |
| 1525 | sync_blockdev(bdev); |
| 1526 | kill_bdev(bdev); |
| 1527 | |
| 1528 | bdev_write_inode(bdev); |
| 1529 | /* |
| 1530 | * Detaching bdev inode from its wb in __destroy_inode() |
| 1531 | * is too late: the queue which embeds its bdi (along with |
| 1532 | * root wb) can be gone as soon as we put_disk() below. |
| 1533 | */ |
| 1534 | inode_detach_wb(bdev->bd_inode); |
| 1535 | } |
| 1536 | if (bdev->bd_contains == bdev) { |
| 1537 | if (disk->fops->release) |
| 1538 | disk->fops->release(disk, mode); |
| 1539 | } |
| 1540 | if (!bdev->bd_openers) { |
| 1541 | struct module *owner = disk->fops->owner; |
| 1542 | |
| 1543 | disk_put_part(bdev->bd_part); |
| 1544 | bdev->bd_part = NULL; |
| 1545 | bdev->bd_disk = NULL; |
| 1546 | if (bdev != bdev->bd_contains) |
| 1547 | victim = bdev->bd_contains; |
| 1548 | bdev->bd_contains = NULL; |
| 1549 | |
| 1550 | put_disk(disk); |
| 1551 | module_put(owner); |
| 1552 | } |
| 1553 | mutex_unlock(&bdev->bd_mutex); |
| 1554 | bdput(bdev); |
| 1555 | if (victim) |
| 1556 | __blkdev_put(victim, mode, 1); |
| 1557 | } |
| 1558 | |
| 1559 | void blkdev_put(struct block_device *bdev, fmode_t mode) |
| 1560 | { |
| 1561 | mutex_lock(&bdev->bd_mutex); |
| 1562 | |
| 1563 | if (mode & FMODE_EXCL) { |
| 1564 | bool bdev_free; |
| 1565 | |
| 1566 | /* |
| 1567 | * Release a claim on the device. The holder fields |
| 1568 | * are protected with bdev_lock. bd_mutex is to |
| 1569 | * synchronize disk_holder unlinking. |
| 1570 | */ |
| 1571 | spin_lock(&bdev_lock); |
| 1572 | |
| 1573 | WARN_ON_ONCE(--bdev->bd_holders < 0); |
| 1574 | WARN_ON_ONCE(--bdev->bd_contains->bd_holders < 0); |
| 1575 | |
| 1576 | /* bd_contains might point to self, check in a separate step */ |
| 1577 | if ((bdev_free = !bdev->bd_holders)) |
| 1578 | bdev->bd_holder = NULL; |
| 1579 | if (!bdev->bd_contains->bd_holders) |
| 1580 | bdev->bd_contains->bd_holder = NULL; |
| 1581 | |
| 1582 | spin_unlock(&bdev_lock); |
| 1583 | |
| 1584 | /* |
| 1585 | * If this was the last claim, remove holder link and |
| 1586 | * unblock evpoll if it was a write holder. |
| 1587 | */ |
| 1588 | if (bdev_free && bdev->bd_write_holder) { |
| 1589 | disk_unblock_events(bdev->bd_disk); |
| 1590 | bdev->bd_write_holder = false; |
| 1591 | } |
| 1592 | } |
| 1593 | |
| 1594 | /* |
| 1595 | * Trigger event checking and tell drivers to flush MEDIA_CHANGE |
| 1596 | * event. This is to ensure detection of media removal commanded |
| 1597 | * from userland - e.g. eject(1). |
| 1598 | */ |
| 1599 | disk_flush_events(bdev->bd_disk, DISK_EVENT_MEDIA_CHANGE); |
| 1600 | |
| 1601 | mutex_unlock(&bdev->bd_mutex); |
| 1602 | |
| 1603 | __blkdev_put(bdev, mode, 0); |
| 1604 | } |
| 1605 | EXPORT_SYMBOL(blkdev_put); |
| 1606 | |
| 1607 | static int blkdev_close(struct inode * inode, struct file * filp) |
| 1608 | { |
| 1609 | struct block_device *bdev = I_BDEV(bdev_file_inode(filp)); |
| 1610 | blkdev_put(bdev, filp->f_mode); |
| 1611 | return 0; |
| 1612 | } |
| 1613 | |
| 1614 | static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg) |
| 1615 | { |
| 1616 | struct block_device *bdev = I_BDEV(bdev_file_inode(file)); |
| 1617 | fmode_t mode = file->f_mode; |
| 1618 | |
| 1619 | /* |
| 1620 | * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have |
| 1621 | * to updated it before every ioctl. |
| 1622 | */ |
| 1623 | if (file->f_flags & O_NDELAY) |
| 1624 | mode |= FMODE_NDELAY; |
| 1625 | else |
| 1626 | mode &= ~FMODE_NDELAY; |
| 1627 | |
| 1628 | return blkdev_ioctl(bdev, mode, cmd, arg); |
| 1629 | } |
| 1630 | |
| 1631 | /* |
| 1632 | * Write data to the block device. Only intended for the block device itself |
| 1633 | * and the raw driver which basically is a fake block device. |
| 1634 | * |
| 1635 | * Does not take i_mutex for the write and thus is not for general purpose |
| 1636 | * use. |
| 1637 | */ |
| 1638 | ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) |
| 1639 | { |
| 1640 | struct file *file = iocb->ki_filp; |
| 1641 | struct inode *bd_inode = bdev_file_inode(file); |
| 1642 | loff_t size = i_size_read(bd_inode); |
| 1643 | struct blk_plug plug; |
| 1644 | ssize_t ret; |
| 1645 | |
| 1646 | if (bdev_read_only(I_BDEV(bd_inode))) |
| 1647 | return -EPERM; |
| 1648 | |
| 1649 | if (!iov_iter_count(from)) |
| 1650 | return 0; |
| 1651 | |
| 1652 | if (iocb->ki_pos >= size) |
| 1653 | return -ENOSPC; |
| 1654 | |
| 1655 | iov_iter_truncate(from, size - iocb->ki_pos); |
| 1656 | |
| 1657 | blk_start_plug(&plug); |
| 1658 | ret = __generic_file_write_iter(iocb, from); |
| 1659 | if (ret > 0) { |
| 1660 | ssize_t err; |
| 1661 | err = generic_write_sync(file, iocb->ki_pos - ret, ret); |
| 1662 | if (err < 0) |
| 1663 | ret = err; |
| 1664 | } |
| 1665 | blk_finish_plug(&plug); |
| 1666 | return ret; |
| 1667 | } |
| 1668 | EXPORT_SYMBOL_GPL(blkdev_write_iter); |
| 1669 | |
| 1670 | ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) |
| 1671 | { |
| 1672 | struct file *file = iocb->ki_filp; |
| 1673 | struct inode *bd_inode = bdev_file_inode(file); |
| 1674 | loff_t size = i_size_read(bd_inode); |
| 1675 | loff_t pos = iocb->ki_pos; |
| 1676 | |
| 1677 | if (pos >= size) |
| 1678 | return 0; |
| 1679 | |
| 1680 | size -= pos; |
| 1681 | iov_iter_truncate(to, size); |
| 1682 | return generic_file_read_iter(iocb, to); |
| 1683 | } |
| 1684 | EXPORT_SYMBOL_GPL(blkdev_read_iter); |
| 1685 | |
| 1686 | /* |
| 1687 | * Try to release a page associated with block device when the system |
| 1688 | * is under memory pressure. |
| 1689 | */ |
| 1690 | static int blkdev_releasepage(struct page *page, gfp_t wait) |
| 1691 | { |
| 1692 | struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super; |
| 1693 | |
| 1694 | if (super && super->s_op->bdev_try_to_free_page) |
| 1695 | return super->s_op->bdev_try_to_free_page(super, page, wait); |
| 1696 | |
| 1697 | return try_to_free_buffers(page); |
| 1698 | } |
| 1699 | |
| 1700 | static int blkdev_writepages(struct address_space *mapping, |
| 1701 | struct writeback_control *wbc) |
| 1702 | { |
| 1703 | if (dax_mapping(mapping)) { |
| 1704 | struct block_device *bdev = I_BDEV(mapping->host); |
| 1705 | |
| 1706 | return dax_writeback_mapping_range(mapping, bdev, wbc); |
| 1707 | } |
| 1708 | return generic_writepages(mapping, wbc); |
| 1709 | } |
| 1710 | |
| 1711 | static const struct address_space_operations def_blk_aops = { |
| 1712 | .readpage = blkdev_readpage, |
| 1713 | .readpages = blkdev_readpages, |
| 1714 | .writepage = blkdev_writepage, |
| 1715 | .write_begin = blkdev_write_begin, |
| 1716 | .write_end = blkdev_write_end, |
| 1717 | .writepages = blkdev_writepages, |
| 1718 | .releasepage = blkdev_releasepage, |
| 1719 | .direct_IO = blkdev_direct_IO, |
| 1720 | .is_dirty_writeback = buffer_check_dirty_writeback, |
| 1721 | }; |
| 1722 | |
| 1723 | #ifdef CONFIG_FS_DAX |
| 1724 | /* |
| 1725 | * In the raw block case we do not need to contend with truncation nor |
| 1726 | * unwritten file extents. Without those concerns there is no need for |
| 1727 | * additional locking beyond the mmap_sem context that these routines |
| 1728 | * are already executing under. |
| 1729 | * |
| 1730 | * Note, there is no protection if the block device is dynamically |
| 1731 | * resized (partition grow/shrink) during a fault. A stable block device |
| 1732 | * size is already not enforced in the blkdev_direct_IO path. |
| 1733 | * |
| 1734 | * For DAX, it is the responsibility of the block device driver to |
| 1735 | * ensure the whole-disk device size is stable while requests are in |
| 1736 | * flight. |
| 1737 | * |
| 1738 | * Finally, unlike the filemap_page_mkwrite() case there is no |
| 1739 | * filesystem superblock to sync against freezing. We still include a |
| 1740 | * pfn_mkwrite callback for dax drivers to receive write fault |
| 1741 | * notifications. |
| 1742 | */ |
| 1743 | static int blkdev_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
| 1744 | { |
| 1745 | return __dax_fault(vma, vmf, blkdev_get_block, NULL); |
| 1746 | } |
| 1747 | |
| 1748 | static int blkdev_dax_pfn_mkwrite(struct vm_area_struct *vma, |
| 1749 | struct vm_fault *vmf) |
| 1750 | { |
| 1751 | return dax_pfn_mkwrite(vma, vmf); |
| 1752 | } |
| 1753 | |
| 1754 | static int blkdev_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr, |
| 1755 | pmd_t *pmd, unsigned int flags) |
| 1756 | { |
| 1757 | return __dax_pmd_fault(vma, addr, pmd, flags, blkdev_get_block, NULL); |
| 1758 | } |
| 1759 | |
| 1760 | static const struct vm_operations_struct blkdev_dax_vm_ops = { |
| 1761 | .fault = blkdev_dax_fault, |
| 1762 | .pmd_fault = blkdev_dax_pmd_fault, |
| 1763 | .pfn_mkwrite = blkdev_dax_pfn_mkwrite, |
| 1764 | }; |
| 1765 | |
| 1766 | static const struct vm_operations_struct blkdev_default_vm_ops = { |
| 1767 | .fault = filemap_fault, |
| 1768 | .map_pages = filemap_map_pages, |
| 1769 | }; |
| 1770 | |
| 1771 | static int blkdev_mmap(struct file *file, struct vm_area_struct *vma) |
| 1772 | { |
| 1773 | struct inode *bd_inode = bdev_file_inode(file); |
| 1774 | |
| 1775 | file_accessed(file); |
| 1776 | if (IS_DAX(bd_inode)) { |
| 1777 | vma->vm_ops = &blkdev_dax_vm_ops; |
| 1778 | vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE; |
| 1779 | } else { |
| 1780 | vma->vm_ops = &blkdev_default_vm_ops; |
| 1781 | } |
| 1782 | |
| 1783 | return 0; |
| 1784 | } |
| 1785 | #else |
| 1786 | #define blkdev_mmap generic_file_mmap |
| 1787 | #endif |
| 1788 | |
| 1789 | const struct file_operations def_blk_fops = { |
| 1790 | .open = blkdev_open, |
| 1791 | .release = blkdev_close, |
| 1792 | .llseek = block_llseek, |
| 1793 | .read_iter = blkdev_read_iter, |
| 1794 | .write_iter = blkdev_write_iter, |
| 1795 | .mmap = blkdev_mmap, |
| 1796 | .fsync = blkdev_fsync, |
| 1797 | .unlocked_ioctl = block_ioctl, |
| 1798 | #ifdef CONFIG_COMPAT |
| 1799 | .compat_ioctl = compat_blkdev_ioctl, |
| 1800 | #endif |
| 1801 | .splice_read = generic_file_splice_read, |
| 1802 | .splice_write = iter_file_splice_write, |
| 1803 | }; |
| 1804 | |
| 1805 | int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg) |
| 1806 | { |
| 1807 | int res; |
| 1808 | mm_segment_t old_fs = get_fs(); |
| 1809 | set_fs(KERNEL_DS); |
| 1810 | res = blkdev_ioctl(bdev, 0, cmd, arg); |
| 1811 | set_fs(old_fs); |
| 1812 | return res; |
| 1813 | } |
| 1814 | |
| 1815 | EXPORT_SYMBOL(ioctl_by_bdev); |
| 1816 | |
| 1817 | /** |
| 1818 | * lookup_bdev - lookup a struct block_device by name |
| 1819 | * @pathname: special file representing the block device |
| 1820 | * |
| 1821 | * Get a reference to the blockdevice at @pathname in the current |
| 1822 | * namespace if possible and return it. Return ERR_PTR(error) |
| 1823 | * otherwise. |
| 1824 | */ |
| 1825 | struct block_device *lookup_bdev(const char *pathname) |
| 1826 | { |
| 1827 | struct block_device *bdev; |
| 1828 | struct inode *inode; |
| 1829 | struct path path; |
| 1830 | int error; |
| 1831 | |
| 1832 | if (!pathname || !*pathname) |
| 1833 | return ERR_PTR(-EINVAL); |
| 1834 | |
| 1835 | error = kern_path(pathname, LOOKUP_FOLLOW, &path); |
| 1836 | if (error) |
| 1837 | return ERR_PTR(error); |
| 1838 | |
| 1839 | inode = d_backing_inode(path.dentry); |
| 1840 | error = -ENOTBLK; |
| 1841 | if (!S_ISBLK(inode->i_mode)) |
| 1842 | goto fail; |
| 1843 | error = -EACCES; |
| 1844 | if (path.mnt->mnt_flags & MNT_NODEV) |
| 1845 | goto fail; |
| 1846 | error = -ENOMEM; |
| 1847 | bdev = bd_acquire(inode); |
| 1848 | if (!bdev) |
| 1849 | goto fail; |
| 1850 | out: |
| 1851 | path_put(&path); |
| 1852 | return bdev; |
| 1853 | fail: |
| 1854 | bdev = ERR_PTR(error); |
| 1855 | goto out; |
| 1856 | } |
| 1857 | EXPORT_SYMBOL(lookup_bdev); |
| 1858 | |
| 1859 | int __invalidate_device(struct block_device *bdev, bool kill_dirty) |
| 1860 | { |
| 1861 | struct super_block *sb = get_super(bdev); |
| 1862 | int res = 0; |
| 1863 | |
| 1864 | if (sb) { |
| 1865 | /* |
| 1866 | * no need to lock the super, get_super holds the |
| 1867 | * read mutex so the filesystem cannot go away |
| 1868 | * under us (->put_super runs with the write lock |
| 1869 | * hold). |
| 1870 | */ |
| 1871 | shrink_dcache_sb(sb); |
| 1872 | res = invalidate_inodes(sb, kill_dirty); |
| 1873 | drop_super(sb); |
| 1874 | } |
| 1875 | invalidate_bdev(bdev); |
| 1876 | return res; |
| 1877 | } |
| 1878 | EXPORT_SYMBOL(__invalidate_device); |
| 1879 | |
| 1880 | void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg) |
| 1881 | { |
| 1882 | struct inode *inode, *old_inode = NULL; |
| 1883 | |
| 1884 | spin_lock(&blockdev_superblock->s_inode_list_lock); |
| 1885 | list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) { |
| 1886 | struct address_space *mapping = inode->i_mapping; |
| 1887 | |
| 1888 | spin_lock(&inode->i_lock); |
| 1889 | if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) || |
| 1890 | mapping->nrpages == 0) { |
| 1891 | spin_unlock(&inode->i_lock); |
| 1892 | continue; |
| 1893 | } |
| 1894 | __iget(inode); |
| 1895 | spin_unlock(&inode->i_lock); |
| 1896 | spin_unlock(&blockdev_superblock->s_inode_list_lock); |
| 1897 | /* |
| 1898 | * We hold a reference to 'inode' so it couldn't have been |
| 1899 | * removed from s_inodes list while we dropped the |
| 1900 | * s_inode_list_lock We cannot iput the inode now as we can |
| 1901 | * be holding the last reference and we cannot iput it under |
| 1902 | * s_inode_list_lock. So we keep the reference and iput it |
| 1903 | * later. |
| 1904 | */ |
| 1905 | iput(old_inode); |
| 1906 | old_inode = inode; |
| 1907 | |
| 1908 | func(I_BDEV(inode), arg); |
| 1909 | |
| 1910 | spin_lock(&blockdev_superblock->s_inode_list_lock); |
| 1911 | } |
| 1912 | spin_unlock(&blockdev_superblock->s_inode_list_lock); |
| 1913 | iput(old_inode); |
| 1914 | } |