Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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/config.h> |
| 9 | #include <linux/init.h> |
| 10 | #include <linux/mm.h> |
| 11 | #include <linux/fcntl.h> |
| 12 | #include <linux/slab.h> |
| 13 | #include <linux/kmod.h> |
| 14 | #include <linux/major.h> |
| 15 | #include <linux/devfs_fs_kernel.h> |
| 16 | #include <linux/smp_lock.h> |
| 17 | #include <linux/highmem.h> |
| 18 | #include <linux/blkdev.h> |
| 19 | #include <linux/module.h> |
| 20 | #include <linux/blkpg.h> |
| 21 | #include <linux/buffer_head.h> |
| 22 | #include <linux/mpage.h> |
| 23 | #include <linux/mount.h> |
| 24 | #include <linux/uio.h> |
| 25 | #include <linux/namei.h> |
| 26 | #include <asm/uaccess.h> |
| 27 | |
| 28 | struct bdev_inode { |
| 29 | struct block_device bdev; |
| 30 | struct inode vfs_inode; |
| 31 | }; |
| 32 | |
| 33 | static inline struct bdev_inode *BDEV_I(struct inode *inode) |
| 34 | { |
| 35 | return container_of(inode, struct bdev_inode, vfs_inode); |
| 36 | } |
| 37 | |
| 38 | inline struct block_device *I_BDEV(struct inode *inode) |
| 39 | { |
| 40 | return &BDEV_I(inode)->bdev; |
| 41 | } |
| 42 | |
| 43 | EXPORT_SYMBOL(I_BDEV); |
| 44 | |
| 45 | static sector_t max_block(struct block_device *bdev) |
| 46 | { |
| 47 | sector_t retval = ~((sector_t)0); |
| 48 | loff_t sz = i_size_read(bdev->bd_inode); |
| 49 | |
| 50 | if (sz) { |
| 51 | unsigned int size = block_size(bdev); |
| 52 | unsigned int sizebits = blksize_bits(size); |
| 53 | retval = (sz >> sizebits); |
| 54 | } |
| 55 | return retval; |
| 56 | } |
| 57 | |
| 58 | /* Kill _all_ buffers, dirty or not.. */ |
| 59 | static void kill_bdev(struct block_device *bdev) |
| 60 | { |
| 61 | invalidate_bdev(bdev, 1); |
| 62 | truncate_inode_pages(bdev->bd_inode->i_mapping, 0); |
| 63 | } |
| 64 | |
| 65 | int set_blocksize(struct block_device *bdev, int size) |
| 66 | { |
| 67 | /* Size must be a power of two, and between 512 and PAGE_SIZE */ |
| 68 | if (size > PAGE_SIZE || size < 512 || (size & (size-1))) |
| 69 | return -EINVAL; |
| 70 | |
| 71 | /* Size cannot be smaller than the size supported by the device */ |
| 72 | if (size < bdev_hardsect_size(bdev)) |
| 73 | return -EINVAL; |
| 74 | |
| 75 | /* Don't change the size if it is same as current */ |
| 76 | if (bdev->bd_block_size != size) { |
| 77 | sync_blockdev(bdev); |
| 78 | bdev->bd_block_size = size; |
| 79 | bdev->bd_inode->i_blkbits = blksize_bits(size); |
| 80 | kill_bdev(bdev); |
| 81 | } |
| 82 | return 0; |
| 83 | } |
| 84 | |
| 85 | EXPORT_SYMBOL(set_blocksize); |
| 86 | |
| 87 | int sb_set_blocksize(struct super_block *sb, int size) |
| 88 | { |
| 89 | int bits = 9; /* 2^9 = 512 */ |
| 90 | |
| 91 | if (set_blocksize(sb->s_bdev, size)) |
| 92 | return 0; |
| 93 | /* If we get here, we know size is power of two |
| 94 | * and it's value is between 512 and PAGE_SIZE */ |
| 95 | sb->s_blocksize = size; |
| 96 | for (size >>= 10; size; size >>= 1) |
| 97 | ++bits; |
| 98 | sb->s_blocksize_bits = bits; |
| 99 | return sb->s_blocksize; |
| 100 | } |
| 101 | |
| 102 | EXPORT_SYMBOL(sb_set_blocksize); |
| 103 | |
| 104 | int sb_min_blocksize(struct super_block *sb, int size) |
| 105 | { |
| 106 | int minsize = bdev_hardsect_size(sb->s_bdev); |
| 107 | if (size < minsize) |
| 108 | size = minsize; |
| 109 | return sb_set_blocksize(sb, size); |
| 110 | } |
| 111 | |
| 112 | EXPORT_SYMBOL(sb_min_blocksize); |
| 113 | |
| 114 | static int |
| 115 | blkdev_get_block(struct inode *inode, sector_t iblock, |
| 116 | struct buffer_head *bh, int create) |
| 117 | { |
| 118 | if (iblock >= max_block(I_BDEV(inode))) { |
| 119 | if (create) |
| 120 | return -EIO; |
| 121 | |
| 122 | /* |
| 123 | * for reads, we're just trying to fill a partial page. |
| 124 | * return a hole, they will have to call get_block again |
| 125 | * before they can fill it, and they will get -EIO at that |
| 126 | * time |
| 127 | */ |
| 128 | return 0; |
| 129 | } |
| 130 | bh->b_bdev = I_BDEV(inode); |
| 131 | bh->b_blocknr = iblock; |
| 132 | set_buffer_mapped(bh); |
| 133 | return 0; |
| 134 | } |
| 135 | |
| 136 | static int |
| 137 | blkdev_get_blocks(struct inode *inode, sector_t iblock, |
| 138 | unsigned long max_blocks, struct buffer_head *bh, int create) |
| 139 | { |
| 140 | sector_t end_block = max_block(I_BDEV(inode)); |
| 141 | |
| 142 | if ((iblock + max_blocks) > end_block) { |
| 143 | max_blocks = end_block - iblock; |
| 144 | if ((long)max_blocks <= 0) { |
| 145 | if (create) |
| 146 | return -EIO; /* write fully beyond EOF */ |
| 147 | /* |
| 148 | * It is a read which is fully beyond EOF. We return |
| 149 | * a !buffer_mapped buffer |
| 150 | */ |
| 151 | max_blocks = 0; |
| 152 | } |
| 153 | } |
| 154 | |
| 155 | bh->b_bdev = I_BDEV(inode); |
| 156 | bh->b_blocknr = iblock; |
| 157 | bh->b_size = max_blocks << inode->i_blkbits; |
| 158 | if (max_blocks) |
| 159 | set_buffer_mapped(bh); |
| 160 | return 0; |
| 161 | } |
| 162 | |
| 163 | static ssize_t |
| 164 | blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, |
| 165 | loff_t offset, unsigned long nr_segs) |
| 166 | { |
| 167 | struct file *file = iocb->ki_filp; |
| 168 | struct inode *inode = file->f_mapping->host; |
| 169 | |
| 170 | return blockdev_direct_IO_no_locking(rw, iocb, inode, I_BDEV(inode), |
| 171 | iov, offset, nr_segs, blkdev_get_blocks, NULL); |
| 172 | } |
| 173 | |
| 174 | static int blkdev_writepage(struct page *page, struct writeback_control *wbc) |
| 175 | { |
| 176 | return block_write_full_page(page, blkdev_get_block, wbc); |
| 177 | } |
| 178 | |
| 179 | static int blkdev_readpage(struct file * file, struct page * page) |
| 180 | { |
| 181 | return block_read_full_page(page, blkdev_get_block); |
| 182 | } |
| 183 | |
| 184 | static int blkdev_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to) |
| 185 | { |
| 186 | return block_prepare_write(page, from, to, blkdev_get_block); |
| 187 | } |
| 188 | |
| 189 | static int blkdev_commit_write(struct file *file, struct page *page, unsigned from, unsigned to) |
| 190 | { |
| 191 | return block_commit_write(page, from, to); |
| 192 | } |
| 193 | |
| 194 | /* |
| 195 | * private llseek: |
| 196 | * for a block special file file->f_dentry->d_inode->i_size is zero |
| 197 | * so we compute the size by hand (just as in block_read/write above) |
| 198 | */ |
| 199 | static loff_t block_llseek(struct file *file, loff_t offset, int origin) |
| 200 | { |
| 201 | struct inode *bd_inode = file->f_mapping->host; |
| 202 | loff_t size; |
| 203 | loff_t retval; |
| 204 | |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 205 | mutex_lock(&bd_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 206 | size = i_size_read(bd_inode); |
| 207 | |
| 208 | switch (origin) { |
| 209 | case 2: |
| 210 | offset += size; |
| 211 | break; |
| 212 | case 1: |
| 213 | offset += file->f_pos; |
| 214 | } |
| 215 | retval = -EINVAL; |
| 216 | if (offset >= 0 && offset <= size) { |
| 217 | if (offset != file->f_pos) { |
| 218 | file->f_pos = offset; |
| 219 | } |
| 220 | retval = offset; |
| 221 | } |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 222 | mutex_unlock(&bd_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 223 | return retval; |
| 224 | } |
| 225 | |
| 226 | /* |
| 227 | * Filp is never NULL; the only case when ->fsync() is called with |
| 228 | * NULL first argument is nfsd_sync_dir() and that's not a directory. |
| 229 | */ |
| 230 | |
| 231 | static int block_fsync(struct file *filp, struct dentry *dentry, int datasync) |
| 232 | { |
| 233 | return sync_blockdev(I_BDEV(filp->f_mapping->host)); |
| 234 | } |
| 235 | |
| 236 | /* |
| 237 | * pseudo-fs |
| 238 | */ |
| 239 | |
| 240 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); |
| 241 | static kmem_cache_t * bdev_cachep; |
| 242 | |
| 243 | static struct inode *bdev_alloc_inode(struct super_block *sb) |
| 244 | { |
| 245 | struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, SLAB_KERNEL); |
| 246 | if (!ei) |
| 247 | return NULL; |
| 248 | return &ei->vfs_inode; |
| 249 | } |
| 250 | |
| 251 | static void bdev_destroy_inode(struct inode *inode) |
| 252 | { |
| 253 | struct bdev_inode *bdi = BDEV_I(inode); |
| 254 | |
| 255 | bdi->bdev.bd_inode_backing_dev_info = NULL; |
| 256 | kmem_cache_free(bdev_cachep, bdi); |
| 257 | } |
| 258 | |
| 259 | static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags) |
| 260 | { |
| 261 | struct bdev_inode *ei = (struct bdev_inode *) foo; |
| 262 | struct block_device *bdev = &ei->bdev; |
| 263 | |
| 264 | if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == |
| 265 | SLAB_CTOR_CONSTRUCTOR) |
| 266 | { |
| 267 | memset(bdev, 0, sizeof(*bdev)); |
Arjan van de Ven | c039e31 | 2006-03-23 03:00:28 -0800 | [diff] [blame] | 268 | mutex_init(&bdev->bd_mutex); |
| 269 | mutex_init(&bdev->bd_mount_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 270 | INIT_LIST_HEAD(&bdev->bd_inodes); |
| 271 | INIT_LIST_HEAD(&bdev->bd_list); |
| 272 | inode_init_once(&ei->vfs_inode); |
| 273 | } |
| 274 | } |
| 275 | |
| 276 | static inline void __bd_forget(struct inode *inode) |
| 277 | { |
| 278 | list_del_init(&inode->i_devices); |
| 279 | inode->i_bdev = NULL; |
| 280 | inode->i_mapping = &inode->i_data; |
| 281 | } |
| 282 | |
| 283 | static void bdev_clear_inode(struct inode *inode) |
| 284 | { |
| 285 | struct block_device *bdev = &BDEV_I(inode)->bdev; |
| 286 | struct list_head *p; |
| 287 | spin_lock(&bdev_lock); |
| 288 | while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) { |
| 289 | __bd_forget(list_entry(p, struct inode, i_devices)); |
| 290 | } |
| 291 | list_del_init(&bdev->bd_list); |
| 292 | spin_unlock(&bdev_lock); |
| 293 | } |
| 294 | |
| 295 | static struct super_operations bdev_sops = { |
| 296 | .statfs = simple_statfs, |
| 297 | .alloc_inode = bdev_alloc_inode, |
| 298 | .destroy_inode = bdev_destroy_inode, |
| 299 | .drop_inode = generic_delete_inode, |
| 300 | .clear_inode = bdev_clear_inode, |
| 301 | }; |
| 302 | |
| 303 | static struct super_block *bd_get_sb(struct file_system_type *fs_type, |
| 304 | int flags, const char *dev_name, void *data) |
| 305 | { |
| 306 | return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576); |
| 307 | } |
| 308 | |
| 309 | static struct file_system_type bd_type = { |
| 310 | .name = "bdev", |
| 311 | .get_sb = bd_get_sb, |
| 312 | .kill_sb = kill_anon_super, |
| 313 | }; |
| 314 | |
| 315 | static struct vfsmount *bd_mnt; |
| 316 | struct super_block *blockdev_superblock; |
| 317 | |
| 318 | void __init bdev_cache_init(void) |
| 319 | { |
| 320 | int err; |
| 321 | bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), |
Paul Jackson | fffb60f | 2006-03-24 03:16:06 -0800 | [diff] [blame] | 322 | 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| |
| 323 | SLAB_MEM_SPREAD|SLAB_PANIC), |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 324 | init_once, NULL); |
| 325 | err = register_filesystem(&bd_type); |
| 326 | if (err) |
| 327 | panic("Cannot register bdev pseudo-fs"); |
| 328 | bd_mnt = kern_mount(&bd_type); |
| 329 | err = PTR_ERR(bd_mnt); |
| 330 | if (IS_ERR(bd_mnt)) |
| 331 | panic("Cannot create bdev pseudo-fs"); |
| 332 | blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ |
| 333 | } |
| 334 | |
| 335 | /* |
| 336 | * Most likely _very_ bad one - but then it's hardly critical for small |
| 337 | * /dev and can be fixed when somebody will need really large one. |
| 338 | * Keep in mind that it will be fed through icache hash function too. |
| 339 | */ |
| 340 | static inline unsigned long hash(dev_t dev) |
| 341 | { |
| 342 | return MAJOR(dev)+MINOR(dev); |
| 343 | } |
| 344 | |
| 345 | static int bdev_test(struct inode *inode, void *data) |
| 346 | { |
| 347 | return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data; |
| 348 | } |
| 349 | |
| 350 | static int bdev_set(struct inode *inode, void *data) |
| 351 | { |
| 352 | BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data; |
| 353 | return 0; |
| 354 | } |
| 355 | |
| 356 | static LIST_HEAD(all_bdevs); |
| 357 | |
| 358 | struct block_device *bdget(dev_t dev) |
| 359 | { |
| 360 | struct block_device *bdev; |
| 361 | struct inode *inode; |
| 362 | |
| 363 | inode = iget5_locked(bd_mnt->mnt_sb, hash(dev), |
| 364 | bdev_test, bdev_set, &dev); |
| 365 | |
| 366 | if (!inode) |
| 367 | return NULL; |
| 368 | |
| 369 | bdev = &BDEV_I(inode)->bdev; |
| 370 | |
| 371 | if (inode->i_state & I_NEW) { |
| 372 | bdev->bd_contains = NULL; |
| 373 | bdev->bd_inode = inode; |
| 374 | bdev->bd_block_size = (1 << inode->i_blkbits); |
| 375 | bdev->bd_part_count = 0; |
| 376 | bdev->bd_invalidated = 0; |
| 377 | inode->i_mode = S_IFBLK; |
| 378 | inode->i_rdev = dev; |
| 379 | inode->i_bdev = bdev; |
| 380 | inode->i_data.a_ops = &def_blk_aops; |
| 381 | mapping_set_gfp_mask(&inode->i_data, GFP_USER); |
| 382 | inode->i_data.backing_dev_info = &default_backing_dev_info; |
| 383 | spin_lock(&bdev_lock); |
| 384 | list_add(&bdev->bd_list, &all_bdevs); |
| 385 | spin_unlock(&bdev_lock); |
| 386 | unlock_new_inode(inode); |
| 387 | } |
| 388 | return bdev; |
| 389 | } |
| 390 | |
| 391 | EXPORT_SYMBOL(bdget); |
| 392 | |
| 393 | long nr_blockdev_pages(void) |
| 394 | { |
| 395 | struct list_head *p; |
| 396 | long ret = 0; |
| 397 | spin_lock(&bdev_lock); |
| 398 | list_for_each(p, &all_bdevs) { |
| 399 | struct block_device *bdev; |
| 400 | bdev = list_entry(p, struct block_device, bd_list); |
| 401 | ret += bdev->bd_inode->i_mapping->nrpages; |
| 402 | } |
| 403 | spin_unlock(&bdev_lock); |
| 404 | return ret; |
| 405 | } |
| 406 | |
| 407 | void bdput(struct block_device *bdev) |
| 408 | { |
| 409 | iput(bdev->bd_inode); |
| 410 | } |
| 411 | |
| 412 | EXPORT_SYMBOL(bdput); |
| 413 | |
| 414 | static struct block_device *bd_acquire(struct inode *inode) |
| 415 | { |
| 416 | struct block_device *bdev; |
| 417 | spin_lock(&bdev_lock); |
| 418 | bdev = inode->i_bdev; |
| 419 | if (bdev && igrab(bdev->bd_inode)) { |
| 420 | spin_unlock(&bdev_lock); |
| 421 | return bdev; |
| 422 | } |
| 423 | spin_unlock(&bdev_lock); |
| 424 | bdev = bdget(inode->i_rdev); |
| 425 | if (bdev) { |
| 426 | spin_lock(&bdev_lock); |
| 427 | if (inode->i_bdev) |
| 428 | __bd_forget(inode); |
| 429 | inode->i_bdev = bdev; |
| 430 | inode->i_mapping = bdev->bd_inode->i_mapping; |
| 431 | list_add(&inode->i_devices, &bdev->bd_inodes); |
| 432 | spin_unlock(&bdev_lock); |
| 433 | } |
| 434 | return bdev; |
| 435 | } |
| 436 | |
| 437 | /* Call when you free inode */ |
| 438 | |
| 439 | void bd_forget(struct inode *inode) |
| 440 | { |
| 441 | spin_lock(&bdev_lock); |
| 442 | if (inode->i_bdev) |
| 443 | __bd_forget(inode); |
| 444 | spin_unlock(&bdev_lock); |
| 445 | } |
| 446 | |
| 447 | int bd_claim(struct block_device *bdev, void *holder) |
| 448 | { |
| 449 | int res; |
| 450 | spin_lock(&bdev_lock); |
| 451 | |
| 452 | /* first decide result */ |
| 453 | if (bdev->bd_holder == holder) |
| 454 | res = 0; /* already a holder */ |
| 455 | else if (bdev->bd_holder != NULL) |
| 456 | res = -EBUSY; /* held by someone else */ |
| 457 | else if (bdev->bd_contains == bdev) |
| 458 | res = 0; /* is a whole device which isn't held */ |
| 459 | |
| 460 | else if (bdev->bd_contains->bd_holder == bd_claim) |
| 461 | res = 0; /* is a partition of a device that is being partitioned */ |
| 462 | else if (bdev->bd_contains->bd_holder != NULL) |
| 463 | res = -EBUSY; /* is a partition of a held device */ |
| 464 | else |
| 465 | res = 0; /* is a partition of an un-held device */ |
| 466 | |
| 467 | /* now impose change */ |
| 468 | if (res==0) { |
| 469 | /* note that for a whole device bd_holders |
| 470 | * will be incremented twice, and bd_holder will |
| 471 | * be set to bd_claim before being set to holder |
| 472 | */ |
| 473 | bdev->bd_contains->bd_holders ++; |
| 474 | bdev->bd_contains->bd_holder = bd_claim; |
| 475 | bdev->bd_holders++; |
| 476 | bdev->bd_holder = holder; |
| 477 | } |
| 478 | spin_unlock(&bdev_lock); |
| 479 | return res; |
| 480 | } |
| 481 | |
| 482 | EXPORT_SYMBOL(bd_claim); |
| 483 | |
| 484 | void bd_release(struct block_device *bdev) |
| 485 | { |
| 486 | spin_lock(&bdev_lock); |
| 487 | if (!--bdev->bd_contains->bd_holders) |
| 488 | bdev->bd_contains->bd_holder = NULL; |
| 489 | if (!--bdev->bd_holders) |
| 490 | bdev->bd_holder = NULL; |
| 491 | spin_unlock(&bdev_lock); |
| 492 | } |
| 493 | |
| 494 | EXPORT_SYMBOL(bd_release); |
| 495 | |
| 496 | /* |
| 497 | * Tries to open block device by device number. Use it ONLY if you |
| 498 | * really do not have anything better - i.e. when you are behind a |
| 499 | * truly sucky interface and all you are given is a device number. _Never_ |
| 500 | * to be used for internal purposes. If you ever need it - reconsider |
| 501 | * your API. |
| 502 | */ |
| 503 | struct block_device *open_by_devnum(dev_t dev, unsigned mode) |
| 504 | { |
| 505 | struct block_device *bdev = bdget(dev); |
| 506 | int err = -ENOMEM; |
| 507 | int flags = mode & FMODE_WRITE ? O_RDWR : O_RDONLY; |
| 508 | if (bdev) |
| 509 | err = blkdev_get(bdev, mode, flags); |
| 510 | return err ? ERR_PTR(err) : bdev; |
| 511 | } |
| 512 | |
| 513 | EXPORT_SYMBOL(open_by_devnum); |
| 514 | |
| 515 | /* |
| 516 | * This routine checks whether a removable media has been changed, |
| 517 | * and invalidates all buffer-cache-entries in that case. This |
| 518 | * is a relatively slow routine, so we have to try to minimize using |
| 519 | * it. Thus it is called only upon a 'mount' or 'open'. This |
| 520 | * is the best way of combining speed and utility, I think. |
| 521 | * People changing diskettes in the middle of an operation deserve |
| 522 | * to lose :-) |
| 523 | */ |
| 524 | int check_disk_change(struct block_device *bdev) |
| 525 | { |
| 526 | struct gendisk *disk = bdev->bd_disk; |
| 527 | struct block_device_operations * bdops = disk->fops; |
| 528 | |
| 529 | if (!bdops->media_changed) |
| 530 | return 0; |
| 531 | if (!bdops->media_changed(bdev->bd_disk)) |
| 532 | return 0; |
| 533 | |
Christoph Hellwig | 2ef4163 | 2005-05-05 16:15:59 -0700 | [diff] [blame] | 534 | if (__invalidate_device(bdev)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 535 | printk("VFS: busy inodes on changed media.\n"); |
| 536 | |
| 537 | if (bdops->revalidate_disk) |
| 538 | bdops->revalidate_disk(bdev->bd_disk); |
| 539 | if (bdev->bd_disk->minors > 1) |
| 540 | bdev->bd_invalidated = 1; |
| 541 | return 1; |
| 542 | } |
| 543 | |
| 544 | EXPORT_SYMBOL(check_disk_change); |
| 545 | |
| 546 | void bd_set_size(struct block_device *bdev, loff_t size) |
| 547 | { |
| 548 | unsigned bsize = bdev_hardsect_size(bdev); |
| 549 | |
| 550 | bdev->bd_inode->i_size = size; |
| 551 | while (bsize < PAGE_CACHE_SIZE) { |
| 552 | if (size & bsize) |
| 553 | break; |
| 554 | bsize <<= 1; |
| 555 | } |
| 556 | bdev->bd_block_size = bsize; |
| 557 | bdev->bd_inode->i_blkbits = blksize_bits(bsize); |
| 558 | } |
| 559 | EXPORT_SYMBOL(bd_set_size); |
| 560 | |
| 561 | static int do_open(struct block_device *bdev, struct file *file) |
| 562 | { |
| 563 | struct module *owner = NULL; |
| 564 | struct gendisk *disk; |
| 565 | int ret = -ENXIO; |
| 566 | int part; |
| 567 | |
| 568 | file->f_mapping = bdev->bd_inode->i_mapping; |
| 569 | lock_kernel(); |
| 570 | disk = get_gendisk(bdev->bd_dev, &part); |
| 571 | if (!disk) { |
| 572 | unlock_kernel(); |
| 573 | bdput(bdev); |
| 574 | return ret; |
| 575 | } |
| 576 | owner = disk->fops->owner; |
| 577 | |
Arjan van de Ven | c039e31 | 2006-03-23 03:00:28 -0800 | [diff] [blame] | 578 | mutex_lock(&bdev->bd_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 579 | if (!bdev->bd_openers) { |
| 580 | bdev->bd_disk = disk; |
| 581 | bdev->bd_contains = bdev; |
| 582 | if (!part) { |
| 583 | struct backing_dev_info *bdi; |
| 584 | if (disk->fops->open) { |
| 585 | ret = disk->fops->open(bdev->bd_inode, file); |
| 586 | if (ret) |
| 587 | goto out_first; |
| 588 | } |
| 589 | if (!bdev->bd_openers) { |
| 590 | bd_set_size(bdev,(loff_t)get_capacity(disk)<<9); |
| 591 | bdi = blk_get_backing_dev_info(bdev); |
| 592 | if (bdi == NULL) |
| 593 | bdi = &default_backing_dev_info; |
| 594 | bdev->bd_inode->i_data.backing_dev_info = bdi; |
| 595 | } |
| 596 | if (bdev->bd_invalidated) |
| 597 | rescan_partitions(disk, bdev); |
| 598 | } else { |
| 599 | struct hd_struct *p; |
| 600 | struct block_device *whole; |
| 601 | whole = bdget_disk(disk, 0); |
| 602 | ret = -ENOMEM; |
| 603 | if (!whole) |
| 604 | goto out_first; |
| 605 | ret = blkdev_get(whole, file->f_mode, file->f_flags); |
| 606 | if (ret) |
| 607 | goto out_first; |
| 608 | bdev->bd_contains = whole; |
Arjan van de Ven | c039e31 | 2006-03-23 03:00:28 -0800 | [diff] [blame] | 609 | mutex_lock(&whole->bd_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 610 | whole->bd_part_count++; |
| 611 | p = disk->part[part - 1]; |
| 612 | bdev->bd_inode->i_data.backing_dev_info = |
| 613 | whole->bd_inode->i_data.backing_dev_info; |
| 614 | if (!(disk->flags & GENHD_FL_UP) || !p || !p->nr_sects) { |
| 615 | whole->bd_part_count--; |
Arjan van de Ven | c039e31 | 2006-03-23 03:00:28 -0800 | [diff] [blame] | 616 | mutex_unlock(&whole->bd_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 617 | ret = -ENXIO; |
| 618 | goto out_first; |
| 619 | } |
| 620 | kobject_get(&p->kobj); |
| 621 | bdev->bd_part = p; |
| 622 | bd_set_size(bdev, (loff_t) p->nr_sects << 9); |
Arjan van de Ven | c039e31 | 2006-03-23 03:00:28 -0800 | [diff] [blame] | 623 | mutex_unlock(&whole->bd_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 624 | } |
| 625 | } else { |
| 626 | put_disk(disk); |
| 627 | module_put(owner); |
| 628 | if (bdev->bd_contains == bdev) { |
| 629 | if (bdev->bd_disk->fops->open) { |
| 630 | ret = bdev->bd_disk->fops->open(bdev->bd_inode, file); |
| 631 | if (ret) |
| 632 | goto out; |
| 633 | } |
| 634 | if (bdev->bd_invalidated) |
| 635 | rescan_partitions(bdev->bd_disk, bdev); |
| 636 | } else { |
Arjan van de Ven | c039e31 | 2006-03-23 03:00:28 -0800 | [diff] [blame] | 637 | mutex_lock(&bdev->bd_contains->bd_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 638 | bdev->bd_contains->bd_part_count++; |
Arjan van de Ven | c039e31 | 2006-03-23 03:00:28 -0800 | [diff] [blame] | 639 | mutex_unlock(&bdev->bd_contains->bd_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 640 | } |
| 641 | } |
| 642 | bdev->bd_openers++; |
Arjan van de Ven | c039e31 | 2006-03-23 03:00:28 -0800 | [diff] [blame] | 643 | mutex_unlock(&bdev->bd_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 644 | unlock_kernel(); |
| 645 | return 0; |
| 646 | |
| 647 | out_first: |
| 648 | bdev->bd_disk = NULL; |
| 649 | bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info; |
| 650 | if (bdev != bdev->bd_contains) |
| 651 | blkdev_put(bdev->bd_contains); |
| 652 | bdev->bd_contains = NULL; |
| 653 | put_disk(disk); |
| 654 | module_put(owner); |
| 655 | out: |
Arjan van de Ven | c039e31 | 2006-03-23 03:00:28 -0800 | [diff] [blame] | 656 | mutex_unlock(&bdev->bd_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 657 | unlock_kernel(); |
| 658 | if (ret) |
| 659 | bdput(bdev); |
| 660 | return ret; |
| 661 | } |
| 662 | |
| 663 | int blkdev_get(struct block_device *bdev, mode_t mode, unsigned flags) |
| 664 | { |
| 665 | /* |
| 666 | * This crockload is due to bad choice of ->open() type. |
| 667 | * It will go away. |
| 668 | * For now, block device ->open() routine must _not_ |
| 669 | * examine anything in 'inode' argument except ->i_rdev. |
| 670 | */ |
| 671 | struct file fake_file = {}; |
| 672 | struct dentry fake_dentry = {}; |
| 673 | fake_file.f_mode = mode; |
| 674 | fake_file.f_flags = flags; |
| 675 | fake_file.f_dentry = &fake_dentry; |
| 676 | fake_dentry.d_inode = bdev->bd_inode; |
| 677 | |
| 678 | return do_open(bdev, &fake_file); |
| 679 | } |
| 680 | |
| 681 | EXPORT_SYMBOL(blkdev_get); |
| 682 | |
| 683 | static int blkdev_open(struct inode * inode, struct file * filp) |
| 684 | { |
| 685 | struct block_device *bdev; |
| 686 | int res; |
| 687 | |
| 688 | /* |
| 689 | * Preserve backwards compatibility and allow large file access |
| 690 | * even if userspace doesn't ask for it explicitly. Some mkfs |
| 691 | * binary needs it. We might want to drop this workaround |
| 692 | * during an unstable branch. |
| 693 | */ |
| 694 | filp->f_flags |= O_LARGEFILE; |
| 695 | |
| 696 | bdev = bd_acquire(inode); |
| 697 | |
| 698 | res = do_open(bdev, filp); |
| 699 | if (res) |
| 700 | return res; |
| 701 | |
| 702 | if (!(filp->f_flags & O_EXCL) ) |
| 703 | return 0; |
| 704 | |
| 705 | if (!(res = bd_claim(bdev, filp))) |
| 706 | return 0; |
| 707 | |
| 708 | blkdev_put(bdev); |
| 709 | return res; |
| 710 | } |
| 711 | |
| 712 | int blkdev_put(struct block_device *bdev) |
| 713 | { |
| 714 | int ret = 0; |
| 715 | struct inode *bd_inode = bdev->bd_inode; |
| 716 | struct gendisk *disk = bdev->bd_disk; |
| 717 | |
Arjan van de Ven | c039e31 | 2006-03-23 03:00:28 -0800 | [diff] [blame] | 718 | mutex_lock(&bdev->bd_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 719 | lock_kernel(); |
| 720 | if (!--bdev->bd_openers) { |
| 721 | sync_blockdev(bdev); |
| 722 | kill_bdev(bdev); |
| 723 | } |
| 724 | if (bdev->bd_contains == bdev) { |
| 725 | if (disk->fops->release) |
| 726 | ret = disk->fops->release(bd_inode, NULL); |
| 727 | } else { |
Arjan van de Ven | c039e31 | 2006-03-23 03:00:28 -0800 | [diff] [blame] | 728 | mutex_lock(&bdev->bd_contains->bd_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 729 | bdev->bd_contains->bd_part_count--; |
Arjan van de Ven | c039e31 | 2006-03-23 03:00:28 -0800 | [diff] [blame] | 730 | mutex_unlock(&bdev->bd_contains->bd_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 731 | } |
| 732 | if (!bdev->bd_openers) { |
| 733 | struct module *owner = disk->fops->owner; |
| 734 | |
| 735 | put_disk(disk); |
| 736 | module_put(owner); |
| 737 | |
| 738 | if (bdev->bd_contains != bdev) { |
| 739 | kobject_put(&bdev->bd_part->kobj); |
| 740 | bdev->bd_part = NULL; |
| 741 | } |
| 742 | bdev->bd_disk = NULL; |
| 743 | bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info; |
| 744 | if (bdev != bdev->bd_contains) { |
| 745 | blkdev_put(bdev->bd_contains); |
| 746 | } |
| 747 | bdev->bd_contains = NULL; |
| 748 | } |
| 749 | unlock_kernel(); |
Arjan van de Ven | c039e31 | 2006-03-23 03:00:28 -0800 | [diff] [blame] | 750 | mutex_unlock(&bdev->bd_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 751 | bdput(bdev); |
| 752 | return ret; |
| 753 | } |
| 754 | |
| 755 | EXPORT_SYMBOL(blkdev_put); |
| 756 | |
| 757 | static int blkdev_close(struct inode * inode, struct file * filp) |
| 758 | { |
| 759 | struct block_device *bdev = I_BDEV(filp->f_mapping->host); |
| 760 | if (bdev->bd_holder == filp) |
| 761 | bd_release(bdev); |
| 762 | return blkdev_put(bdev); |
| 763 | } |
| 764 | |
| 765 | static ssize_t blkdev_file_write(struct file *file, const char __user *buf, |
| 766 | size_t count, loff_t *ppos) |
| 767 | { |
| 768 | struct iovec local_iov = { .iov_base = (void __user *)buf, .iov_len = count }; |
| 769 | |
| 770 | return generic_file_write_nolock(file, &local_iov, 1, ppos); |
| 771 | } |
| 772 | |
| 773 | static ssize_t blkdev_file_aio_write(struct kiocb *iocb, const char __user *buf, |
| 774 | size_t count, loff_t pos) |
| 775 | { |
| 776 | struct iovec local_iov = { .iov_base = (void __user *)buf, .iov_len = count }; |
| 777 | |
| 778 | return generic_file_aio_write_nolock(iocb, &local_iov, 1, &iocb->ki_pos); |
| 779 | } |
| 780 | |
Arnd Bergmann | bb93e3a | 2005-06-23 00:10:15 -0700 | [diff] [blame] | 781 | static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 782 | { |
| 783 | return blkdev_ioctl(file->f_mapping->host, file, cmd, arg); |
| 784 | } |
| 785 | |
| 786 | struct address_space_operations def_blk_aops = { |
| 787 | .readpage = blkdev_readpage, |
| 788 | .writepage = blkdev_writepage, |
| 789 | .sync_page = block_sync_page, |
| 790 | .prepare_write = blkdev_prepare_write, |
| 791 | .commit_write = blkdev_commit_write, |
| 792 | .writepages = generic_writepages, |
| 793 | .direct_IO = blkdev_direct_IO, |
| 794 | }; |
| 795 | |
| 796 | struct file_operations def_blk_fops = { |
| 797 | .open = blkdev_open, |
| 798 | .release = blkdev_close, |
| 799 | .llseek = block_llseek, |
| 800 | .read = generic_file_read, |
| 801 | .write = blkdev_file_write, |
| 802 | .aio_read = generic_file_aio_read, |
| 803 | .aio_write = blkdev_file_aio_write, |
| 804 | .mmap = generic_file_mmap, |
| 805 | .fsync = block_fsync, |
Arnd Bergmann | bb93e3a | 2005-06-23 00:10:15 -0700 | [diff] [blame] | 806 | .unlocked_ioctl = block_ioctl, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 807 | #ifdef CONFIG_COMPAT |
| 808 | .compat_ioctl = compat_blkdev_ioctl, |
| 809 | #endif |
| 810 | .readv = generic_file_readv, |
| 811 | .writev = generic_file_write_nolock, |
| 812 | .sendfile = generic_file_sendfile, |
| 813 | }; |
| 814 | |
| 815 | int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg) |
| 816 | { |
| 817 | int res; |
| 818 | mm_segment_t old_fs = get_fs(); |
| 819 | set_fs(KERNEL_DS); |
| 820 | res = blkdev_ioctl(bdev->bd_inode, NULL, cmd, arg); |
| 821 | set_fs(old_fs); |
| 822 | return res; |
| 823 | } |
| 824 | |
| 825 | EXPORT_SYMBOL(ioctl_by_bdev); |
| 826 | |
| 827 | /** |
| 828 | * lookup_bdev - lookup a struct block_device by name |
| 829 | * |
| 830 | * @path: special file representing the block device |
| 831 | * |
| 832 | * Get a reference to the blockdevice at @path in the current |
| 833 | * namespace if possible and return it. Return ERR_PTR(error) |
| 834 | * otherwise. |
| 835 | */ |
| 836 | struct block_device *lookup_bdev(const char *path) |
| 837 | { |
| 838 | struct block_device *bdev; |
| 839 | struct inode *inode; |
| 840 | struct nameidata nd; |
| 841 | int error; |
| 842 | |
| 843 | if (!path || !*path) |
| 844 | return ERR_PTR(-EINVAL); |
| 845 | |
| 846 | error = path_lookup(path, LOOKUP_FOLLOW, &nd); |
| 847 | if (error) |
| 848 | return ERR_PTR(error); |
| 849 | |
| 850 | inode = nd.dentry->d_inode; |
| 851 | error = -ENOTBLK; |
| 852 | if (!S_ISBLK(inode->i_mode)) |
| 853 | goto fail; |
| 854 | error = -EACCES; |
| 855 | if (nd.mnt->mnt_flags & MNT_NODEV) |
| 856 | goto fail; |
| 857 | error = -ENOMEM; |
| 858 | bdev = bd_acquire(inode); |
| 859 | if (!bdev) |
| 860 | goto fail; |
| 861 | out: |
| 862 | path_release(&nd); |
| 863 | return bdev; |
| 864 | fail: |
| 865 | bdev = ERR_PTR(error); |
| 866 | goto out; |
| 867 | } |
| 868 | |
| 869 | /** |
| 870 | * open_bdev_excl - open a block device by name and set it up for use |
| 871 | * |
| 872 | * @path: special file representing the block device |
| 873 | * @flags: %MS_RDONLY for opening read-only |
| 874 | * @holder: owner for exclusion |
| 875 | * |
| 876 | * Open the blockdevice described by the special file at @path, claim it |
| 877 | * for the @holder. |
| 878 | */ |
| 879 | struct block_device *open_bdev_excl(const char *path, int flags, void *holder) |
| 880 | { |
| 881 | struct block_device *bdev; |
| 882 | mode_t mode = FMODE_READ; |
| 883 | int error = 0; |
| 884 | |
| 885 | bdev = lookup_bdev(path); |
| 886 | if (IS_ERR(bdev)) |
| 887 | return bdev; |
| 888 | |
| 889 | if (!(flags & MS_RDONLY)) |
| 890 | mode |= FMODE_WRITE; |
| 891 | error = blkdev_get(bdev, mode, 0); |
| 892 | if (error) |
| 893 | return ERR_PTR(error); |
| 894 | error = -EACCES; |
| 895 | if (!(flags & MS_RDONLY) && bdev_read_only(bdev)) |
| 896 | goto blkdev_put; |
| 897 | error = bd_claim(bdev, holder); |
| 898 | if (error) |
| 899 | goto blkdev_put; |
| 900 | |
| 901 | return bdev; |
| 902 | |
| 903 | blkdev_put: |
| 904 | blkdev_put(bdev); |
| 905 | return ERR_PTR(error); |
| 906 | } |
| 907 | |
| 908 | EXPORT_SYMBOL(open_bdev_excl); |
| 909 | |
| 910 | /** |
| 911 | * close_bdev_excl - release a blockdevice openen by open_bdev_excl() |
| 912 | * |
| 913 | * @bdev: blockdevice to close |
| 914 | * |
| 915 | * This is the counterpart to open_bdev_excl(). |
| 916 | */ |
| 917 | void close_bdev_excl(struct block_device *bdev) |
| 918 | { |
| 919 | bd_release(bdev); |
| 920 | blkdev_put(bdev); |
| 921 | } |
| 922 | |
| 923 | EXPORT_SYMBOL(close_bdev_excl); |