Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Resizable virtual memory filesystem for Linux. |
| 3 | * |
| 4 | * Copyright (C) 2000 Linus Torvalds. |
| 5 | * 2000 Transmeta Corp. |
| 6 | * 2000-2001 Christoph Rohland |
| 7 | * 2000-2001 SAP AG |
| 8 | * 2002 Red Hat Inc. |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 9 | * Copyright (C) 2002-2005 Hugh Dickins. |
| 10 | * Copyright (C) 2002-2005 VERITAS Software Corporation. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 11 | * Copyright (C) 2004 Andi Kleen, SuSE Labs |
| 12 | * |
| 13 | * Extended attribute support for tmpfs: |
| 14 | * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net> |
| 15 | * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> |
| 16 | * |
| 17 | * This file is released under the GPL. |
| 18 | */ |
| 19 | |
| 20 | /* |
| 21 | * This virtual memory filesystem is heavily based on the ramfs. It |
| 22 | * extends ramfs by the ability to use swap and honor resource limits |
| 23 | * which makes it a completely usable filesystem. |
| 24 | */ |
| 25 | |
| 26 | #include <linux/config.h> |
| 27 | #include <linux/module.h> |
| 28 | #include <linux/init.h> |
| 29 | #include <linux/devfs_fs_kernel.h> |
| 30 | #include <linux/fs.h> |
| 31 | #include <linux/mm.h> |
| 32 | #include <linux/mman.h> |
| 33 | #include <linux/file.h> |
| 34 | #include <linux/swap.h> |
| 35 | #include <linux/pagemap.h> |
| 36 | #include <linux/string.h> |
| 37 | #include <linux/slab.h> |
| 38 | #include <linux/backing-dev.h> |
| 39 | #include <linux/shmem_fs.h> |
| 40 | #include <linux/mount.h> |
| 41 | #include <linux/writeback.h> |
| 42 | #include <linux/vfs.h> |
| 43 | #include <linux/blkdev.h> |
| 44 | #include <linux/security.h> |
| 45 | #include <linux/swapops.h> |
| 46 | #include <linux/mempolicy.h> |
| 47 | #include <linux/namei.h> |
Hugh Dickins | b00dc3a | 2006-02-21 23:49:47 +0000 | [diff] [blame] | 48 | #include <linux/ctype.h> |
Lee Schermerhorn | 304dbdb | 2006-04-22 02:35:48 -0700 | [diff] [blame] | 49 | #include <linux/migrate.h> |
| 50 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 51 | #include <asm/uaccess.h> |
| 52 | #include <asm/div64.h> |
| 53 | #include <asm/pgtable.h> |
| 54 | |
| 55 | /* This magic number is used in glibc for posix shared memory */ |
| 56 | #define TMPFS_MAGIC 0x01021994 |
| 57 | |
| 58 | #define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long)) |
| 59 | #define ENTRIES_PER_PAGEPAGE (ENTRIES_PER_PAGE*ENTRIES_PER_PAGE) |
| 60 | #define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512) |
| 61 | |
| 62 | #define SHMEM_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1)) |
| 63 | #define SHMEM_MAX_BYTES ((unsigned long long)SHMEM_MAX_INDEX << PAGE_CACHE_SHIFT) |
| 64 | |
| 65 | #define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT) |
| 66 | |
| 67 | /* info->flags needs VM_flags to handle pagein/truncate races efficiently */ |
| 68 | #define SHMEM_PAGEIN VM_READ |
| 69 | #define SHMEM_TRUNCATE VM_WRITE |
| 70 | |
| 71 | /* Definition to limit shmem_truncate's steps between cond_rescheds */ |
| 72 | #define LATENCY_LIMIT 64 |
| 73 | |
| 74 | /* Pretend that each entry is of this size in directory's i_size */ |
| 75 | #define BOGO_DIRENT_SIZE 20 |
| 76 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 77 | /* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */ |
| 78 | enum sgp_type { |
| 79 | SGP_QUICK, /* don't try more than file page cache lookup */ |
| 80 | SGP_READ, /* don't exceed i_size, don't allocate page */ |
| 81 | SGP_CACHE, /* don't exceed i_size, may allocate page */ |
| 82 | SGP_WRITE, /* may exceed i_size, may allocate page */ |
| 83 | }; |
| 84 | |
| 85 | static int shmem_getpage(struct inode *inode, unsigned long idx, |
| 86 | struct page **pagep, enum sgp_type sgp, int *type); |
| 87 | |
Al Viro | 6daa0e2 | 2005-10-21 03:18:50 -0400 | [diff] [blame] | 88 | static inline struct page *shmem_dir_alloc(gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 89 | { |
| 90 | /* |
| 91 | * The above definition of ENTRIES_PER_PAGE, and the use of |
| 92 | * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE: |
| 93 | * might be reconsidered if it ever diverges from PAGE_SIZE. |
| 94 | */ |
| 95 | return alloc_pages(gfp_mask, PAGE_CACHE_SHIFT-PAGE_SHIFT); |
| 96 | } |
| 97 | |
| 98 | static inline void shmem_dir_free(struct page *page) |
| 99 | { |
| 100 | __free_pages(page, PAGE_CACHE_SHIFT-PAGE_SHIFT); |
| 101 | } |
| 102 | |
| 103 | static struct page **shmem_dir_map(struct page *page) |
| 104 | { |
| 105 | return (struct page **)kmap_atomic(page, KM_USER0); |
| 106 | } |
| 107 | |
| 108 | static inline void shmem_dir_unmap(struct page **dir) |
| 109 | { |
| 110 | kunmap_atomic(dir, KM_USER0); |
| 111 | } |
| 112 | |
| 113 | static swp_entry_t *shmem_swp_map(struct page *page) |
| 114 | { |
| 115 | return (swp_entry_t *)kmap_atomic(page, KM_USER1); |
| 116 | } |
| 117 | |
| 118 | static inline void shmem_swp_balance_unmap(void) |
| 119 | { |
| 120 | /* |
| 121 | * When passing a pointer to an i_direct entry, to code which |
| 122 | * also handles indirect entries and so will shmem_swp_unmap, |
| 123 | * we must arrange for the preempt count to remain in balance. |
| 124 | * What kmap_atomic of a lowmem page does depends on config |
| 125 | * and architecture, so pretend to kmap_atomic some lowmem page. |
| 126 | */ |
| 127 | (void) kmap_atomic(ZERO_PAGE(0), KM_USER1); |
| 128 | } |
| 129 | |
| 130 | static inline void shmem_swp_unmap(swp_entry_t *entry) |
| 131 | { |
| 132 | kunmap_atomic(entry, KM_USER1); |
| 133 | } |
| 134 | |
| 135 | static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) |
| 136 | { |
| 137 | return sb->s_fs_info; |
| 138 | } |
| 139 | |
| 140 | /* |
| 141 | * shmem_file_setup pre-accounts the whole fixed size of a VM object, |
| 142 | * for shared memory and for shared anonymous (/dev/zero) mappings |
| 143 | * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), |
| 144 | * consistent with the pre-accounting of private mappings ... |
| 145 | */ |
| 146 | static inline int shmem_acct_size(unsigned long flags, loff_t size) |
| 147 | { |
| 148 | return (flags & VM_ACCOUNT)? |
| 149 | security_vm_enough_memory(VM_ACCT(size)): 0; |
| 150 | } |
| 151 | |
| 152 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) |
| 153 | { |
| 154 | if (flags & VM_ACCOUNT) |
| 155 | vm_unacct_memory(VM_ACCT(size)); |
| 156 | } |
| 157 | |
| 158 | /* |
| 159 | * ... whereas tmpfs objects are accounted incrementally as |
| 160 | * pages are allocated, in order to allow huge sparse files. |
| 161 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, |
| 162 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. |
| 163 | */ |
| 164 | static inline int shmem_acct_block(unsigned long flags) |
| 165 | { |
| 166 | return (flags & VM_ACCOUNT)? |
| 167 | 0: security_vm_enough_memory(VM_ACCT(PAGE_CACHE_SIZE)); |
| 168 | } |
| 169 | |
| 170 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) |
| 171 | { |
| 172 | if (!(flags & VM_ACCOUNT)) |
| 173 | vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); |
| 174 | } |
| 175 | |
| 176 | static struct super_operations shmem_ops; |
| 177 | static struct address_space_operations shmem_aops; |
| 178 | static struct file_operations shmem_file_operations; |
| 179 | static struct inode_operations shmem_inode_operations; |
| 180 | static struct inode_operations shmem_dir_inode_operations; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 181 | static struct vm_operations_struct shmem_vm_ops; |
| 182 | |
Ravikiran G Thirumalai | 6c231b7 | 2005-09-06 15:17:45 -0700 | [diff] [blame] | 183 | static struct backing_dev_info shmem_backing_dev_info __read_mostly = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 184 | .ra_pages = 0, /* No readahead */ |
| 185 | .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK, |
| 186 | .unplug_io_fn = default_unplug_io_fn, |
| 187 | }; |
| 188 | |
| 189 | static LIST_HEAD(shmem_swaplist); |
| 190 | static DEFINE_SPINLOCK(shmem_swaplist_lock); |
| 191 | |
| 192 | static void shmem_free_blocks(struct inode *inode, long pages) |
| 193 | { |
| 194 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 195 | if (sbinfo->max_blocks) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 196 | spin_lock(&sbinfo->stat_lock); |
| 197 | sbinfo->free_blocks += pages; |
| 198 | inode->i_blocks -= pages*BLOCKS_PER_PAGE; |
| 199 | spin_unlock(&sbinfo->stat_lock); |
| 200 | } |
| 201 | } |
| 202 | |
| 203 | /* |
| 204 | * shmem_recalc_inode - recalculate the size of an inode |
| 205 | * |
| 206 | * @inode: inode to recalc |
| 207 | * |
| 208 | * We have to calculate the free blocks since the mm can drop |
| 209 | * undirtied hole pages behind our back. |
| 210 | * |
| 211 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped |
| 212 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) |
| 213 | * |
| 214 | * It has to be called with the spinlock held. |
| 215 | */ |
| 216 | static void shmem_recalc_inode(struct inode *inode) |
| 217 | { |
| 218 | struct shmem_inode_info *info = SHMEM_I(inode); |
| 219 | long freed; |
| 220 | |
| 221 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; |
| 222 | if (freed > 0) { |
| 223 | info->alloced -= freed; |
| 224 | shmem_unacct_blocks(info->flags, freed); |
| 225 | shmem_free_blocks(inode, freed); |
| 226 | } |
| 227 | } |
| 228 | |
| 229 | /* |
| 230 | * shmem_swp_entry - find the swap vector position in the info structure |
| 231 | * |
| 232 | * @info: info structure for the inode |
| 233 | * @index: index of the page to find |
| 234 | * @page: optional page to add to the structure. Has to be preset to |
| 235 | * all zeros |
| 236 | * |
| 237 | * If there is no space allocated yet it will return NULL when |
| 238 | * page is NULL, else it will use the page for the needed block, |
| 239 | * setting it to NULL on return to indicate that it has been used. |
| 240 | * |
| 241 | * The swap vector is organized the following way: |
| 242 | * |
| 243 | * There are SHMEM_NR_DIRECT entries directly stored in the |
| 244 | * shmem_inode_info structure. So small files do not need an addional |
| 245 | * allocation. |
| 246 | * |
| 247 | * For pages with index > SHMEM_NR_DIRECT there is the pointer |
| 248 | * i_indirect which points to a page which holds in the first half |
| 249 | * doubly indirect blocks, in the second half triple indirect blocks: |
| 250 | * |
| 251 | * For an artificial ENTRIES_PER_PAGE = 4 this would lead to the |
| 252 | * following layout (for SHMEM_NR_DIRECT == 16): |
| 253 | * |
| 254 | * i_indirect -> dir --> 16-19 |
| 255 | * | +-> 20-23 |
| 256 | * | |
| 257 | * +-->dir2 --> 24-27 |
| 258 | * | +-> 28-31 |
| 259 | * | +-> 32-35 |
| 260 | * | +-> 36-39 |
| 261 | * | |
| 262 | * +-->dir3 --> 40-43 |
| 263 | * +-> 44-47 |
| 264 | * +-> 48-51 |
| 265 | * +-> 52-55 |
| 266 | */ |
| 267 | static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page) |
| 268 | { |
| 269 | unsigned long offset; |
| 270 | struct page **dir; |
| 271 | struct page *subdir; |
| 272 | |
| 273 | if (index < SHMEM_NR_DIRECT) { |
| 274 | shmem_swp_balance_unmap(); |
| 275 | return info->i_direct+index; |
| 276 | } |
| 277 | if (!info->i_indirect) { |
| 278 | if (page) { |
| 279 | info->i_indirect = *page; |
| 280 | *page = NULL; |
| 281 | } |
| 282 | return NULL; /* need another page */ |
| 283 | } |
| 284 | |
| 285 | index -= SHMEM_NR_DIRECT; |
| 286 | offset = index % ENTRIES_PER_PAGE; |
| 287 | index /= ENTRIES_PER_PAGE; |
| 288 | dir = shmem_dir_map(info->i_indirect); |
| 289 | |
| 290 | if (index >= ENTRIES_PER_PAGE/2) { |
| 291 | index -= ENTRIES_PER_PAGE/2; |
| 292 | dir += ENTRIES_PER_PAGE/2 + index/ENTRIES_PER_PAGE; |
| 293 | index %= ENTRIES_PER_PAGE; |
| 294 | subdir = *dir; |
| 295 | if (!subdir) { |
| 296 | if (page) { |
| 297 | *dir = *page; |
| 298 | *page = NULL; |
| 299 | } |
| 300 | shmem_dir_unmap(dir); |
| 301 | return NULL; /* need another page */ |
| 302 | } |
| 303 | shmem_dir_unmap(dir); |
| 304 | dir = shmem_dir_map(subdir); |
| 305 | } |
| 306 | |
| 307 | dir += index; |
| 308 | subdir = *dir; |
| 309 | if (!subdir) { |
| 310 | if (!page || !(subdir = *page)) { |
| 311 | shmem_dir_unmap(dir); |
| 312 | return NULL; /* need a page */ |
| 313 | } |
| 314 | *dir = subdir; |
| 315 | *page = NULL; |
| 316 | } |
| 317 | shmem_dir_unmap(dir); |
| 318 | return shmem_swp_map(subdir) + offset; |
| 319 | } |
| 320 | |
| 321 | static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value) |
| 322 | { |
| 323 | long incdec = value? 1: -1; |
| 324 | |
| 325 | entry->val = value; |
| 326 | info->swapped += incdec; |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 327 | if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) { |
| 328 | struct page *page = kmap_atomic_to_page(entry); |
| 329 | set_page_private(page, page_private(page) + incdec); |
| 330 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 331 | } |
| 332 | |
| 333 | /* |
| 334 | * shmem_swp_alloc - get the position of the swap entry for the page. |
| 335 | * If it does not exist allocate the entry. |
| 336 | * |
| 337 | * @info: info structure for the inode |
| 338 | * @index: index of the page to find |
| 339 | * @sgp: check and recheck i_size? skip allocation? |
| 340 | */ |
| 341 | static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long index, enum sgp_type sgp) |
| 342 | { |
| 343 | struct inode *inode = &info->vfs_inode; |
| 344 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
| 345 | struct page *page = NULL; |
| 346 | swp_entry_t *entry; |
| 347 | |
| 348 | if (sgp != SGP_WRITE && |
| 349 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) |
| 350 | return ERR_PTR(-EINVAL); |
| 351 | |
| 352 | while (!(entry = shmem_swp_entry(info, index, &page))) { |
| 353 | if (sgp == SGP_READ) |
| 354 | return shmem_swp_map(ZERO_PAGE(0)); |
| 355 | /* |
| 356 | * Test free_blocks against 1 not 0, since we have 1 data |
| 357 | * page (and perhaps indirect index pages) yet to allocate: |
| 358 | * a waste to allocate index if we cannot allocate data. |
| 359 | */ |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 360 | if (sbinfo->max_blocks) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 361 | spin_lock(&sbinfo->stat_lock); |
| 362 | if (sbinfo->free_blocks <= 1) { |
| 363 | spin_unlock(&sbinfo->stat_lock); |
| 364 | return ERR_PTR(-ENOSPC); |
| 365 | } |
| 366 | sbinfo->free_blocks--; |
| 367 | inode->i_blocks += BLOCKS_PER_PAGE; |
| 368 | spin_unlock(&sbinfo->stat_lock); |
| 369 | } |
| 370 | |
| 371 | spin_unlock(&info->lock); |
| 372 | page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping) | __GFP_ZERO); |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 373 | if (page) |
| 374 | set_page_private(page, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 375 | spin_lock(&info->lock); |
| 376 | |
| 377 | if (!page) { |
| 378 | shmem_free_blocks(inode, 1); |
| 379 | return ERR_PTR(-ENOMEM); |
| 380 | } |
| 381 | if (sgp != SGP_WRITE && |
| 382 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { |
| 383 | entry = ERR_PTR(-EINVAL); |
| 384 | break; |
| 385 | } |
| 386 | if (info->next_index <= index) |
| 387 | info->next_index = index + 1; |
| 388 | } |
| 389 | if (page) { |
| 390 | /* another task gave its page, or truncated the file */ |
| 391 | shmem_free_blocks(inode, 1); |
| 392 | shmem_dir_free(page); |
| 393 | } |
| 394 | if (info->next_index <= index && !IS_ERR(entry)) |
| 395 | info->next_index = index + 1; |
| 396 | return entry; |
| 397 | } |
| 398 | |
| 399 | /* |
| 400 | * shmem_free_swp - free some swap entries in a directory |
| 401 | * |
| 402 | * @dir: pointer to the directory |
| 403 | * @edir: pointer after last entry of the directory |
| 404 | */ |
| 405 | static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir) |
| 406 | { |
| 407 | swp_entry_t *ptr; |
| 408 | int freed = 0; |
| 409 | |
| 410 | for (ptr = dir; ptr < edir; ptr++) { |
| 411 | if (ptr->val) { |
| 412 | free_swap_and_cache(*ptr); |
| 413 | *ptr = (swp_entry_t){0}; |
| 414 | freed++; |
| 415 | } |
| 416 | } |
| 417 | return freed; |
| 418 | } |
| 419 | |
| 420 | static int shmem_map_and_free_swp(struct page *subdir, |
| 421 | int offset, int limit, struct page ***dir) |
| 422 | { |
| 423 | swp_entry_t *ptr; |
| 424 | int freed = 0; |
| 425 | |
| 426 | ptr = shmem_swp_map(subdir); |
| 427 | for (; offset < limit; offset += LATENCY_LIMIT) { |
| 428 | int size = limit - offset; |
| 429 | if (size > LATENCY_LIMIT) |
| 430 | size = LATENCY_LIMIT; |
| 431 | freed += shmem_free_swp(ptr+offset, ptr+offset+size); |
| 432 | if (need_resched()) { |
| 433 | shmem_swp_unmap(ptr); |
| 434 | if (*dir) { |
| 435 | shmem_dir_unmap(*dir); |
| 436 | *dir = NULL; |
| 437 | } |
| 438 | cond_resched(); |
| 439 | ptr = shmem_swp_map(subdir); |
| 440 | } |
| 441 | } |
| 442 | shmem_swp_unmap(ptr); |
| 443 | return freed; |
| 444 | } |
| 445 | |
| 446 | static void shmem_free_pages(struct list_head *next) |
| 447 | { |
| 448 | struct page *page; |
| 449 | int freed = 0; |
| 450 | |
| 451 | do { |
| 452 | page = container_of(next, struct page, lru); |
| 453 | next = next->next; |
| 454 | shmem_dir_free(page); |
| 455 | freed++; |
| 456 | if (freed >= LATENCY_LIMIT) { |
| 457 | cond_resched(); |
| 458 | freed = 0; |
| 459 | } |
| 460 | } while (next); |
| 461 | } |
| 462 | |
Badari Pulavarty | f6b3ec2 | 2006-01-06 00:10:38 -0800 | [diff] [blame] | 463 | static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 464 | { |
| 465 | struct shmem_inode_info *info = SHMEM_I(inode); |
| 466 | unsigned long idx; |
| 467 | unsigned long size; |
| 468 | unsigned long limit; |
| 469 | unsigned long stage; |
| 470 | unsigned long diroff; |
| 471 | struct page **dir; |
| 472 | struct page *topdir; |
| 473 | struct page *middir; |
| 474 | struct page *subdir; |
| 475 | swp_entry_t *ptr; |
| 476 | LIST_HEAD(pages_to_free); |
| 477 | long nr_pages_to_free = 0; |
| 478 | long nr_swaps_freed = 0; |
| 479 | int offset; |
| 480 | int freed; |
Badari Pulavarty | f6b3ec2 | 2006-01-06 00:10:38 -0800 | [diff] [blame] | 481 | int punch_hole = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 482 | |
| 483 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; |
Badari Pulavarty | f6b3ec2 | 2006-01-06 00:10:38 -0800 | [diff] [blame] | 484 | idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 485 | if (idx >= info->next_index) |
| 486 | return; |
| 487 | |
| 488 | spin_lock(&info->lock); |
| 489 | info->flags |= SHMEM_TRUNCATE; |
Badari Pulavarty | f6b3ec2 | 2006-01-06 00:10:38 -0800 | [diff] [blame] | 490 | if (likely(end == (loff_t) -1)) { |
| 491 | limit = info->next_index; |
| 492 | info->next_index = idx; |
| 493 | } else { |
| 494 | limit = (end + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
| 495 | if (limit > info->next_index) |
| 496 | limit = info->next_index; |
| 497 | punch_hole = 1; |
| 498 | } |
| 499 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 500 | topdir = info->i_indirect; |
Badari Pulavarty | f6b3ec2 | 2006-01-06 00:10:38 -0800 | [diff] [blame] | 501 | if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 502 | info->i_indirect = NULL; |
| 503 | nr_pages_to_free++; |
| 504 | list_add(&topdir->lru, &pages_to_free); |
| 505 | } |
| 506 | spin_unlock(&info->lock); |
| 507 | |
| 508 | if (info->swapped && idx < SHMEM_NR_DIRECT) { |
| 509 | ptr = info->i_direct; |
| 510 | size = limit; |
| 511 | if (size > SHMEM_NR_DIRECT) |
| 512 | size = SHMEM_NR_DIRECT; |
| 513 | nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size); |
| 514 | } |
| 515 | if (!topdir) |
| 516 | goto done2; |
| 517 | |
| 518 | BUG_ON(limit <= SHMEM_NR_DIRECT); |
| 519 | limit -= SHMEM_NR_DIRECT; |
| 520 | idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0; |
| 521 | offset = idx % ENTRIES_PER_PAGE; |
| 522 | idx -= offset; |
| 523 | |
| 524 | dir = shmem_dir_map(topdir); |
| 525 | stage = ENTRIES_PER_PAGEPAGE/2; |
| 526 | if (idx < ENTRIES_PER_PAGEPAGE/2) { |
| 527 | middir = topdir; |
| 528 | diroff = idx/ENTRIES_PER_PAGE; |
| 529 | } else { |
| 530 | dir += ENTRIES_PER_PAGE/2; |
| 531 | dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE; |
| 532 | while (stage <= idx) |
| 533 | stage += ENTRIES_PER_PAGEPAGE; |
| 534 | middir = *dir; |
| 535 | if (*dir) { |
| 536 | diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) % |
| 537 | ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE; |
| 538 | if (!diroff && !offset) { |
| 539 | *dir = NULL; |
| 540 | nr_pages_to_free++; |
| 541 | list_add(&middir->lru, &pages_to_free); |
| 542 | } |
| 543 | shmem_dir_unmap(dir); |
| 544 | dir = shmem_dir_map(middir); |
| 545 | } else { |
| 546 | diroff = 0; |
| 547 | offset = 0; |
| 548 | idx = stage; |
| 549 | } |
| 550 | } |
| 551 | |
| 552 | for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) { |
| 553 | if (unlikely(idx == stage)) { |
| 554 | shmem_dir_unmap(dir); |
| 555 | dir = shmem_dir_map(topdir) + |
| 556 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; |
| 557 | while (!*dir) { |
| 558 | dir++; |
| 559 | idx += ENTRIES_PER_PAGEPAGE; |
| 560 | if (idx >= limit) |
| 561 | goto done1; |
| 562 | } |
| 563 | stage = idx + ENTRIES_PER_PAGEPAGE; |
| 564 | middir = *dir; |
| 565 | *dir = NULL; |
| 566 | nr_pages_to_free++; |
| 567 | list_add(&middir->lru, &pages_to_free); |
| 568 | shmem_dir_unmap(dir); |
| 569 | cond_resched(); |
| 570 | dir = shmem_dir_map(middir); |
| 571 | diroff = 0; |
| 572 | } |
| 573 | subdir = dir[diroff]; |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 574 | if (subdir && page_private(subdir)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 575 | size = limit - idx; |
| 576 | if (size > ENTRIES_PER_PAGE) |
| 577 | size = ENTRIES_PER_PAGE; |
| 578 | freed = shmem_map_and_free_swp(subdir, |
| 579 | offset, size, &dir); |
| 580 | if (!dir) |
| 581 | dir = shmem_dir_map(middir); |
| 582 | nr_swaps_freed += freed; |
| 583 | if (offset) |
| 584 | spin_lock(&info->lock); |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 585 | set_page_private(subdir, page_private(subdir) - freed); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 586 | if (offset) |
| 587 | spin_unlock(&info->lock); |
Badari Pulavarty | f6b3ec2 | 2006-01-06 00:10:38 -0800 | [diff] [blame] | 588 | if (!punch_hole) |
| 589 | BUG_ON(page_private(subdir) > offset); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 590 | } |
| 591 | if (offset) |
| 592 | offset = 0; |
Badari Pulavarty | f6b3ec2 | 2006-01-06 00:10:38 -0800 | [diff] [blame] | 593 | else if (subdir && !page_private(subdir)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 594 | dir[diroff] = NULL; |
| 595 | nr_pages_to_free++; |
| 596 | list_add(&subdir->lru, &pages_to_free); |
| 597 | } |
| 598 | } |
| 599 | done1: |
| 600 | shmem_dir_unmap(dir); |
| 601 | done2: |
| 602 | if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) { |
| 603 | /* |
| 604 | * Call truncate_inode_pages again: racing shmem_unuse_inode |
| 605 | * may have swizzled a page in from swap since vmtruncate or |
| 606 | * generic_delete_inode did it, before we lowered next_index. |
| 607 | * Also, though shmem_getpage checks i_size before adding to |
| 608 | * cache, no recheck after: so fix the narrow window there too. |
| 609 | */ |
Badari Pulavarty | f6b3ec2 | 2006-01-06 00:10:38 -0800 | [diff] [blame] | 610 | truncate_inode_pages_range(inode->i_mapping, start, end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 611 | } |
| 612 | |
| 613 | spin_lock(&info->lock); |
| 614 | info->flags &= ~SHMEM_TRUNCATE; |
| 615 | info->swapped -= nr_swaps_freed; |
| 616 | if (nr_pages_to_free) |
| 617 | shmem_free_blocks(inode, nr_pages_to_free); |
| 618 | shmem_recalc_inode(inode); |
| 619 | spin_unlock(&info->lock); |
| 620 | |
| 621 | /* |
| 622 | * Empty swap vector directory pages to be freed? |
| 623 | */ |
| 624 | if (!list_empty(&pages_to_free)) { |
| 625 | pages_to_free.prev->next = NULL; |
| 626 | shmem_free_pages(pages_to_free.next); |
| 627 | } |
| 628 | } |
| 629 | |
Badari Pulavarty | f6b3ec2 | 2006-01-06 00:10:38 -0800 | [diff] [blame] | 630 | static void shmem_truncate(struct inode *inode) |
| 631 | { |
| 632 | shmem_truncate_range(inode, inode->i_size, (loff_t)-1); |
| 633 | } |
| 634 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 635 | static int shmem_notify_change(struct dentry *dentry, struct iattr *attr) |
| 636 | { |
| 637 | struct inode *inode = dentry->d_inode; |
| 638 | struct page *page = NULL; |
| 639 | int error; |
| 640 | |
| 641 | if (attr->ia_valid & ATTR_SIZE) { |
| 642 | if (attr->ia_size < inode->i_size) { |
| 643 | /* |
| 644 | * If truncating down to a partial page, then |
| 645 | * if that page is already allocated, hold it |
| 646 | * in memory until the truncation is over, so |
| 647 | * truncate_partial_page cannnot miss it were |
| 648 | * it assigned to swap. |
| 649 | */ |
| 650 | if (attr->ia_size & (PAGE_CACHE_SIZE-1)) { |
| 651 | (void) shmem_getpage(inode, |
| 652 | attr->ia_size>>PAGE_CACHE_SHIFT, |
| 653 | &page, SGP_READ, NULL); |
| 654 | } |
| 655 | /* |
| 656 | * Reset SHMEM_PAGEIN flag so that shmem_truncate can |
| 657 | * detect if any pages might have been added to cache |
| 658 | * after truncate_inode_pages. But we needn't bother |
| 659 | * if it's being fully truncated to zero-length: the |
| 660 | * nrpages check is efficient enough in that case. |
| 661 | */ |
| 662 | if (attr->ia_size) { |
| 663 | struct shmem_inode_info *info = SHMEM_I(inode); |
| 664 | spin_lock(&info->lock); |
| 665 | info->flags &= ~SHMEM_PAGEIN; |
| 666 | spin_unlock(&info->lock); |
| 667 | } |
| 668 | } |
| 669 | } |
| 670 | |
| 671 | error = inode_change_ok(inode, attr); |
| 672 | if (!error) |
| 673 | error = inode_setattr(inode, attr); |
| 674 | if (page) |
| 675 | page_cache_release(page); |
| 676 | return error; |
| 677 | } |
| 678 | |
| 679 | static void shmem_delete_inode(struct inode *inode) |
| 680 | { |
| 681 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
| 682 | struct shmem_inode_info *info = SHMEM_I(inode); |
| 683 | |
| 684 | if (inode->i_op->truncate == shmem_truncate) { |
Mark Fasheh | fef2665 | 2005-09-09 13:01:31 -0700 | [diff] [blame] | 685 | truncate_inode_pages(inode->i_mapping, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 686 | shmem_unacct_size(info->flags, inode->i_size); |
| 687 | inode->i_size = 0; |
| 688 | shmem_truncate(inode); |
| 689 | if (!list_empty(&info->swaplist)) { |
| 690 | spin_lock(&shmem_swaplist_lock); |
| 691 | list_del_init(&info->swaplist); |
| 692 | spin_unlock(&shmem_swaplist_lock); |
| 693 | } |
| 694 | } |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 695 | BUG_ON(inode->i_blocks); |
| 696 | if (sbinfo->max_inodes) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 697 | spin_lock(&sbinfo->stat_lock); |
| 698 | sbinfo->free_inodes++; |
| 699 | spin_unlock(&sbinfo->stat_lock); |
| 700 | } |
| 701 | clear_inode(inode); |
| 702 | } |
| 703 | |
| 704 | static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir) |
| 705 | { |
| 706 | swp_entry_t *ptr; |
| 707 | |
| 708 | for (ptr = dir; ptr < edir; ptr++) { |
| 709 | if (ptr->val == entry.val) |
| 710 | return ptr - dir; |
| 711 | } |
| 712 | return -1; |
| 713 | } |
| 714 | |
| 715 | static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page) |
| 716 | { |
| 717 | struct inode *inode; |
| 718 | unsigned long idx; |
| 719 | unsigned long size; |
| 720 | unsigned long limit; |
| 721 | unsigned long stage; |
| 722 | struct page **dir; |
| 723 | struct page *subdir; |
| 724 | swp_entry_t *ptr; |
| 725 | int offset; |
| 726 | |
| 727 | idx = 0; |
| 728 | ptr = info->i_direct; |
| 729 | spin_lock(&info->lock); |
| 730 | limit = info->next_index; |
| 731 | size = limit; |
| 732 | if (size > SHMEM_NR_DIRECT) |
| 733 | size = SHMEM_NR_DIRECT; |
| 734 | offset = shmem_find_swp(entry, ptr, ptr+size); |
| 735 | if (offset >= 0) { |
| 736 | shmem_swp_balance_unmap(); |
| 737 | goto found; |
| 738 | } |
| 739 | if (!info->i_indirect) |
| 740 | goto lost2; |
| 741 | |
| 742 | dir = shmem_dir_map(info->i_indirect); |
| 743 | stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2; |
| 744 | |
| 745 | for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) { |
| 746 | if (unlikely(idx == stage)) { |
| 747 | shmem_dir_unmap(dir-1); |
| 748 | dir = shmem_dir_map(info->i_indirect) + |
| 749 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; |
| 750 | while (!*dir) { |
| 751 | dir++; |
| 752 | idx += ENTRIES_PER_PAGEPAGE; |
| 753 | if (idx >= limit) |
| 754 | goto lost1; |
| 755 | } |
| 756 | stage = idx + ENTRIES_PER_PAGEPAGE; |
| 757 | subdir = *dir; |
| 758 | shmem_dir_unmap(dir); |
| 759 | dir = shmem_dir_map(subdir); |
| 760 | } |
| 761 | subdir = *dir; |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 762 | if (subdir && page_private(subdir)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 763 | ptr = shmem_swp_map(subdir); |
| 764 | size = limit - idx; |
| 765 | if (size > ENTRIES_PER_PAGE) |
| 766 | size = ENTRIES_PER_PAGE; |
| 767 | offset = shmem_find_swp(entry, ptr, ptr+size); |
| 768 | if (offset >= 0) { |
| 769 | shmem_dir_unmap(dir); |
| 770 | goto found; |
| 771 | } |
| 772 | shmem_swp_unmap(ptr); |
| 773 | } |
| 774 | } |
| 775 | lost1: |
| 776 | shmem_dir_unmap(dir-1); |
| 777 | lost2: |
| 778 | spin_unlock(&info->lock); |
| 779 | return 0; |
| 780 | found: |
| 781 | idx += offset; |
| 782 | inode = &info->vfs_inode; |
| 783 | if (move_from_swap_cache(page, idx, inode->i_mapping) == 0) { |
| 784 | info->flags |= SHMEM_PAGEIN; |
| 785 | shmem_swp_set(info, ptr + offset, 0); |
| 786 | } |
| 787 | shmem_swp_unmap(ptr); |
| 788 | spin_unlock(&info->lock); |
| 789 | /* |
| 790 | * Decrement swap count even when the entry is left behind: |
| 791 | * try_to_unuse will skip over mms, then reincrement count. |
| 792 | */ |
| 793 | swap_free(entry); |
| 794 | return 1; |
| 795 | } |
| 796 | |
| 797 | /* |
| 798 | * shmem_unuse() search for an eventually swapped out shmem page. |
| 799 | */ |
| 800 | int shmem_unuse(swp_entry_t entry, struct page *page) |
| 801 | { |
| 802 | struct list_head *p, *next; |
| 803 | struct shmem_inode_info *info; |
| 804 | int found = 0; |
| 805 | |
| 806 | spin_lock(&shmem_swaplist_lock); |
| 807 | list_for_each_safe(p, next, &shmem_swaplist) { |
| 808 | info = list_entry(p, struct shmem_inode_info, swaplist); |
| 809 | if (!info->swapped) |
| 810 | list_del_init(&info->swaplist); |
| 811 | else if (shmem_unuse_inode(info, entry, page)) { |
| 812 | /* move head to start search for next from here */ |
| 813 | list_move_tail(&shmem_swaplist, &info->swaplist); |
| 814 | found = 1; |
| 815 | break; |
| 816 | } |
| 817 | } |
| 818 | spin_unlock(&shmem_swaplist_lock); |
| 819 | return found; |
| 820 | } |
| 821 | |
| 822 | /* |
| 823 | * Move the page from the page cache to the swap cache. |
| 824 | */ |
| 825 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) |
| 826 | { |
| 827 | struct shmem_inode_info *info; |
| 828 | swp_entry_t *entry, swap; |
| 829 | struct address_space *mapping; |
| 830 | unsigned long index; |
| 831 | struct inode *inode; |
| 832 | |
| 833 | BUG_ON(!PageLocked(page)); |
| 834 | BUG_ON(page_mapped(page)); |
| 835 | |
| 836 | mapping = page->mapping; |
| 837 | index = page->index; |
| 838 | inode = mapping->host; |
| 839 | info = SHMEM_I(inode); |
| 840 | if (info->flags & VM_LOCKED) |
| 841 | goto redirty; |
| 842 | swap = get_swap_page(); |
| 843 | if (!swap.val) |
| 844 | goto redirty; |
| 845 | |
| 846 | spin_lock(&info->lock); |
| 847 | shmem_recalc_inode(inode); |
| 848 | if (index >= info->next_index) { |
| 849 | BUG_ON(!(info->flags & SHMEM_TRUNCATE)); |
| 850 | goto unlock; |
| 851 | } |
| 852 | entry = shmem_swp_entry(info, index, NULL); |
| 853 | BUG_ON(!entry); |
| 854 | BUG_ON(entry->val); |
| 855 | |
| 856 | if (move_to_swap_cache(page, swap) == 0) { |
| 857 | shmem_swp_set(info, entry, swap.val); |
| 858 | shmem_swp_unmap(entry); |
| 859 | spin_unlock(&info->lock); |
| 860 | if (list_empty(&info->swaplist)) { |
| 861 | spin_lock(&shmem_swaplist_lock); |
| 862 | /* move instead of add in case we're racing */ |
| 863 | list_move_tail(&info->swaplist, &shmem_swaplist); |
| 864 | spin_unlock(&shmem_swaplist_lock); |
| 865 | } |
| 866 | unlock_page(page); |
| 867 | return 0; |
| 868 | } |
| 869 | |
| 870 | shmem_swp_unmap(entry); |
| 871 | unlock: |
| 872 | spin_unlock(&info->lock); |
| 873 | swap_free(swap); |
| 874 | redirty: |
| 875 | set_page_dirty(page); |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 876 | return AOP_WRITEPAGE_ACTIVATE; /* Return with the page locked */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 877 | } |
| 878 | |
| 879 | #ifdef CONFIG_NUMA |
Hugh Dickins | d15c023 | 2006-03-22 00:08:46 -0800 | [diff] [blame] | 880 | static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes) |
Hugh Dickins | b00dc3a | 2006-02-21 23:49:47 +0000 | [diff] [blame] | 881 | { |
| 882 | char *nodelist = strchr(value, ':'); |
| 883 | int err = 1; |
| 884 | |
| 885 | if (nodelist) { |
| 886 | /* NUL-terminate policy string */ |
| 887 | *nodelist++ = '\0'; |
| 888 | if (nodelist_parse(nodelist, *policy_nodes)) |
| 889 | goto out; |
| 890 | } |
| 891 | if (!strcmp(value, "default")) { |
| 892 | *policy = MPOL_DEFAULT; |
| 893 | /* Don't allow a nodelist */ |
| 894 | if (!nodelist) |
| 895 | err = 0; |
| 896 | } else if (!strcmp(value, "prefer")) { |
| 897 | *policy = MPOL_PREFERRED; |
| 898 | /* Insist on a nodelist of one node only */ |
| 899 | if (nodelist) { |
| 900 | char *rest = nodelist; |
| 901 | while (isdigit(*rest)) |
| 902 | rest++; |
| 903 | if (!*rest) |
| 904 | err = 0; |
| 905 | } |
| 906 | } else if (!strcmp(value, "bind")) { |
| 907 | *policy = MPOL_BIND; |
| 908 | /* Insist on a nodelist */ |
| 909 | if (nodelist) |
| 910 | err = 0; |
| 911 | } else if (!strcmp(value, "interleave")) { |
| 912 | *policy = MPOL_INTERLEAVE; |
| 913 | /* Default to nodes online if no nodelist */ |
| 914 | if (!nodelist) |
| 915 | *policy_nodes = node_online_map; |
| 916 | err = 0; |
| 917 | } |
| 918 | out: |
| 919 | /* Restore string for error message */ |
| 920 | if (nodelist) |
| 921 | *--nodelist = ':'; |
| 922 | return err; |
| 923 | } |
| 924 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 925 | static struct page *shmem_swapin_async(struct shared_policy *p, |
| 926 | swp_entry_t entry, unsigned long idx) |
| 927 | { |
| 928 | struct page *page; |
| 929 | struct vm_area_struct pvma; |
| 930 | |
| 931 | /* Create a pseudo vma that just contains the policy */ |
| 932 | memset(&pvma, 0, sizeof(struct vm_area_struct)); |
| 933 | pvma.vm_end = PAGE_SIZE; |
| 934 | pvma.vm_pgoff = idx; |
| 935 | pvma.vm_policy = mpol_shared_policy_lookup(p, idx); |
| 936 | page = read_swap_cache_async(entry, &pvma, 0); |
| 937 | mpol_free(pvma.vm_policy); |
| 938 | return page; |
| 939 | } |
| 940 | |
| 941 | struct page *shmem_swapin(struct shmem_inode_info *info, swp_entry_t entry, |
| 942 | unsigned long idx) |
| 943 | { |
| 944 | struct shared_policy *p = &info->policy; |
| 945 | int i, num; |
| 946 | struct page *page; |
| 947 | unsigned long offset; |
| 948 | |
| 949 | num = valid_swaphandles(entry, &offset); |
| 950 | for (i = 0; i < num; offset++, i++) { |
| 951 | page = shmem_swapin_async(p, |
| 952 | swp_entry(swp_type(entry), offset), idx); |
| 953 | if (!page) |
| 954 | break; |
| 955 | page_cache_release(page); |
| 956 | } |
| 957 | lru_add_drain(); /* Push any new pages onto the LRU now */ |
| 958 | return shmem_swapin_async(p, entry, idx); |
| 959 | } |
| 960 | |
| 961 | static struct page * |
Al Viro | 6daa0e2 | 2005-10-21 03:18:50 -0400 | [diff] [blame] | 962 | shmem_alloc_page(gfp_t gfp, struct shmem_inode_info *info, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 963 | unsigned long idx) |
| 964 | { |
| 965 | struct vm_area_struct pvma; |
| 966 | struct page *page; |
| 967 | |
| 968 | memset(&pvma, 0, sizeof(struct vm_area_struct)); |
| 969 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); |
| 970 | pvma.vm_pgoff = idx; |
| 971 | pvma.vm_end = PAGE_SIZE; |
| 972 | page = alloc_page_vma(gfp | __GFP_ZERO, &pvma, 0); |
| 973 | mpol_free(pvma.vm_policy); |
| 974 | return page; |
| 975 | } |
| 976 | #else |
Hugh Dickins | b00dc3a | 2006-02-21 23:49:47 +0000 | [diff] [blame] | 977 | static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes) |
| 978 | { |
| 979 | return 1; |
| 980 | } |
| 981 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 982 | static inline struct page * |
| 983 | shmem_swapin(struct shmem_inode_info *info,swp_entry_t entry,unsigned long idx) |
| 984 | { |
| 985 | swapin_readahead(entry, 0, NULL); |
| 986 | return read_swap_cache_async(entry, NULL, 0); |
| 987 | } |
| 988 | |
| 989 | static inline struct page * |
Al Viro | dd0fc66 | 2005-10-07 07:46:04 +0100 | [diff] [blame] | 990 | shmem_alloc_page(gfp_t gfp,struct shmem_inode_info *info, unsigned long idx) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 991 | { |
| 992 | return alloc_page(gfp | __GFP_ZERO); |
| 993 | } |
| 994 | #endif |
| 995 | |
| 996 | /* |
| 997 | * shmem_getpage - either get the page from swap or allocate a new one |
| 998 | * |
| 999 | * If we allocate a new one we do not mark it dirty. That's up to the |
| 1000 | * vm. If we swap it in we mark it dirty since we also free the swap |
| 1001 | * entry since a page cannot live in both the swap and page cache |
| 1002 | */ |
| 1003 | static int shmem_getpage(struct inode *inode, unsigned long idx, |
| 1004 | struct page **pagep, enum sgp_type sgp, int *type) |
| 1005 | { |
| 1006 | struct address_space *mapping = inode->i_mapping; |
| 1007 | struct shmem_inode_info *info = SHMEM_I(inode); |
| 1008 | struct shmem_sb_info *sbinfo; |
| 1009 | struct page *filepage = *pagep; |
| 1010 | struct page *swappage; |
| 1011 | swp_entry_t *entry; |
| 1012 | swp_entry_t swap; |
| 1013 | int error; |
| 1014 | |
| 1015 | if (idx >= SHMEM_MAX_INDEX) |
| 1016 | return -EFBIG; |
| 1017 | /* |
| 1018 | * Normally, filepage is NULL on entry, and either found |
| 1019 | * uptodate immediately, or allocated and zeroed, or read |
| 1020 | * in under swappage, which is then assigned to filepage. |
| 1021 | * But shmem_prepare_write passes in a locked filepage, |
| 1022 | * which may be found not uptodate by other callers too, |
| 1023 | * and may need to be copied from the swappage read in. |
| 1024 | */ |
| 1025 | repeat: |
| 1026 | if (!filepage) |
| 1027 | filepage = find_lock_page(mapping, idx); |
| 1028 | if (filepage && PageUptodate(filepage)) |
| 1029 | goto done; |
| 1030 | error = 0; |
| 1031 | if (sgp == SGP_QUICK) |
| 1032 | goto failed; |
| 1033 | |
| 1034 | spin_lock(&info->lock); |
| 1035 | shmem_recalc_inode(inode); |
| 1036 | entry = shmem_swp_alloc(info, idx, sgp); |
| 1037 | if (IS_ERR(entry)) { |
| 1038 | spin_unlock(&info->lock); |
| 1039 | error = PTR_ERR(entry); |
| 1040 | goto failed; |
| 1041 | } |
| 1042 | swap = *entry; |
| 1043 | |
| 1044 | if (swap.val) { |
| 1045 | /* Look it up and read it in.. */ |
| 1046 | swappage = lookup_swap_cache(swap); |
| 1047 | if (!swappage) { |
| 1048 | shmem_swp_unmap(entry); |
| 1049 | spin_unlock(&info->lock); |
| 1050 | /* here we actually do the io */ |
| 1051 | if (type && *type == VM_FAULT_MINOR) { |
| 1052 | inc_page_state(pgmajfault); |
| 1053 | *type = VM_FAULT_MAJOR; |
| 1054 | } |
| 1055 | swappage = shmem_swapin(info, swap, idx); |
| 1056 | if (!swappage) { |
| 1057 | spin_lock(&info->lock); |
| 1058 | entry = shmem_swp_alloc(info, idx, sgp); |
| 1059 | if (IS_ERR(entry)) |
| 1060 | error = PTR_ERR(entry); |
| 1061 | else { |
| 1062 | if (entry->val == swap.val) |
| 1063 | error = -ENOMEM; |
| 1064 | shmem_swp_unmap(entry); |
| 1065 | } |
| 1066 | spin_unlock(&info->lock); |
| 1067 | if (error) |
| 1068 | goto failed; |
| 1069 | goto repeat; |
| 1070 | } |
| 1071 | wait_on_page_locked(swappage); |
| 1072 | page_cache_release(swappage); |
| 1073 | goto repeat; |
| 1074 | } |
| 1075 | |
| 1076 | /* We have to do this with page locked to prevent races */ |
| 1077 | if (TestSetPageLocked(swappage)) { |
| 1078 | shmem_swp_unmap(entry); |
| 1079 | spin_unlock(&info->lock); |
| 1080 | wait_on_page_locked(swappage); |
| 1081 | page_cache_release(swappage); |
| 1082 | goto repeat; |
| 1083 | } |
Christoph Lameter | b16664e | 2006-02-01 03:05:36 -0800 | [diff] [blame] | 1084 | if (!PageSwapCache(swappage)) { |
| 1085 | /* Page migration has occured */ |
| 1086 | shmem_swp_unmap(entry); |
| 1087 | spin_unlock(&info->lock); |
| 1088 | unlock_page(swappage); |
| 1089 | page_cache_release(swappage); |
| 1090 | goto repeat; |
| 1091 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1092 | if (PageWriteback(swappage)) { |
| 1093 | shmem_swp_unmap(entry); |
| 1094 | spin_unlock(&info->lock); |
| 1095 | wait_on_page_writeback(swappage); |
| 1096 | unlock_page(swappage); |
| 1097 | page_cache_release(swappage); |
| 1098 | goto repeat; |
| 1099 | } |
| 1100 | if (!PageUptodate(swappage)) { |
| 1101 | shmem_swp_unmap(entry); |
| 1102 | spin_unlock(&info->lock); |
| 1103 | unlock_page(swappage); |
| 1104 | page_cache_release(swappage); |
| 1105 | error = -EIO; |
| 1106 | goto failed; |
| 1107 | } |
| 1108 | |
| 1109 | if (filepage) { |
| 1110 | shmem_swp_set(info, entry, 0); |
| 1111 | shmem_swp_unmap(entry); |
| 1112 | delete_from_swap_cache(swappage); |
| 1113 | spin_unlock(&info->lock); |
| 1114 | copy_highpage(filepage, swappage); |
| 1115 | unlock_page(swappage); |
| 1116 | page_cache_release(swappage); |
| 1117 | flush_dcache_page(filepage); |
| 1118 | SetPageUptodate(filepage); |
| 1119 | set_page_dirty(filepage); |
| 1120 | swap_free(swap); |
| 1121 | } else if (!(error = move_from_swap_cache( |
| 1122 | swappage, idx, mapping))) { |
| 1123 | info->flags |= SHMEM_PAGEIN; |
| 1124 | shmem_swp_set(info, entry, 0); |
| 1125 | shmem_swp_unmap(entry); |
| 1126 | spin_unlock(&info->lock); |
| 1127 | filepage = swappage; |
| 1128 | swap_free(swap); |
| 1129 | } else { |
| 1130 | shmem_swp_unmap(entry); |
| 1131 | spin_unlock(&info->lock); |
| 1132 | unlock_page(swappage); |
| 1133 | page_cache_release(swappage); |
| 1134 | if (error == -ENOMEM) { |
| 1135 | /* let kswapd refresh zone for GFP_ATOMICs */ |
| 1136 | blk_congestion_wait(WRITE, HZ/50); |
| 1137 | } |
| 1138 | goto repeat; |
| 1139 | } |
| 1140 | } else if (sgp == SGP_READ && !filepage) { |
| 1141 | shmem_swp_unmap(entry); |
| 1142 | filepage = find_get_page(mapping, idx); |
| 1143 | if (filepage && |
| 1144 | (!PageUptodate(filepage) || TestSetPageLocked(filepage))) { |
| 1145 | spin_unlock(&info->lock); |
| 1146 | wait_on_page_locked(filepage); |
| 1147 | page_cache_release(filepage); |
| 1148 | filepage = NULL; |
| 1149 | goto repeat; |
| 1150 | } |
| 1151 | spin_unlock(&info->lock); |
| 1152 | } else { |
| 1153 | shmem_swp_unmap(entry); |
| 1154 | sbinfo = SHMEM_SB(inode->i_sb); |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 1155 | if (sbinfo->max_blocks) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1156 | spin_lock(&sbinfo->stat_lock); |
| 1157 | if (sbinfo->free_blocks == 0 || |
| 1158 | shmem_acct_block(info->flags)) { |
| 1159 | spin_unlock(&sbinfo->stat_lock); |
| 1160 | spin_unlock(&info->lock); |
| 1161 | error = -ENOSPC; |
| 1162 | goto failed; |
| 1163 | } |
| 1164 | sbinfo->free_blocks--; |
| 1165 | inode->i_blocks += BLOCKS_PER_PAGE; |
| 1166 | spin_unlock(&sbinfo->stat_lock); |
| 1167 | } else if (shmem_acct_block(info->flags)) { |
| 1168 | spin_unlock(&info->lock); |
| 1169 | error = -ENOSPC; |
| 1170 | goto failed; |
| 1171 | } |
| 1172 | |
| 1173 | if (!filepage) { |
| 1174 | spin_unlock(&info->lock); |
| 1175 | filepage = shmem_alloc_page(mapping_gfp_mask(mapping), |
| 1176 | info, |
| 1177 | idx); |
| 1178 | if (!filepage) { |
| 1179 | shmem_unacct_blocks(info->flags, 1); |
| 1180 | shmem_free_blocks(inode, 1); |
| 1181 | error = -ENOMEM; |
| 1182 | goto failed; |
| 1183 | } |
| 1184 | |
| 1185 | spin_lock(&info->lock); |
| 1186 | entry = shmem_swp_alloc(info, idx, sgp); |
| 1187 | if (IS_ERR(entry)) |
| 1188 | error = PTR_ERR(entry); |
| 1189 | else { |
| 1190 | swap = *entry; |
| 1191 | shmem_swp_unmap(entry); |
| 1192 | } |
| 1193 | if (error || swap.val || 0 != add_to_page_cache_lru( |
| 1194 | filepage, mapping, idx, GFP_ATOMIC)) { |
| 1195 | spin_unlock(&info->lock); |
| 1196 | page_cache_release(filepage); |
| 1197 | shmem_unacct_blocks(info->flags, 1); |
| 1198 | shmem_free_blocks(inode, 1); |
| 1199 | filepage = NULL; |
| 1200 | if (error) |
| 1201 | goto failed; |
| 1202 | goto repeat; |
| 1203 | } |
| 1204 | info->flags |= SHMEM_PAGEIN; |
| 1205 | } |
| 1206 | |
| 1207 | info->alloced++; |
| 1208 | spin_unlock(&info->lock); |
| 1209 | flush_dcache_page(filepage); |
| 1210 | SetPageUptodate(filepage); |
| 1211 | } |
| 1212 | done: |
| 1213 | if (*pagep != filepage) { |
| 1214 | unlock_page(filepage); |
| 1215 | *pagep = filepage; |
| 1216 | } |
| 1217 | return 0; |
| 1218 | |
| 1219 | failed: |
| 1220 | if (*pagep != filepage) { |
| 1221 | unlock_page(filepage); |
| 1222 | page_cache_release(filepage); |
| 1223 | } |
| 1224 | return error; |
| 1225 | } |
| 1226 | |
| 1227 | struct page *shmem_nopage(struct vm_area_struct *vma, unsigned long address, int *type) |
| 1228 | { |
| 1229 | struct inode *inode = vma->vm_file->f_dentry->d_inode; |
| 1230 | struct page *page = NULL; |
| 1231 | unsigned long idx; |
| 1232 | int error; |
| 1233 | |
| 1234 | idx = (address - vma->vm_start) >> PAGE_SHIFT; |
| 1235 | idx += vma->vm_pgoff; |
| 1236 | idx >>= PAGE_CACHE_SHIFT - PAGE_SHIFT; |
| 1237 | if (((loff_t) idx << PAGE_CACHE_SHIFT) >= i_size_read(inode)) |
| 1238 | return NOPAGE_SIGBUS; |
| 1239 | |
| 1240 | error = shmem_getpage(inode, idx, &page, SGP_CACHE, type); |
| 1241 | if (error) |
| 1242 | return (error == -ENOMEM)? NOPAGE_OOM: NOPAGE_SIGBUS; |
| 1243 | |
| 1244 | mark_page_accessed(page); |
| 1245 | return page; |
| 1246 | } |
| 1247 | |
| 1248 | static int shmem_populate(struct vm_area_struct *vma, |
| 1249 | unsigned long addr, unsigned long len, |
| 1250 | pgprot_t prot, unsigned long pgoff, int nonblock) |
| 1251 | { |
| 1252 | struct inode *inode = vma->vm_file->f_dentry->d_inode; |
| 1253 | struct mm_struct *mm = vma->vm_mm; |
| 1254 | enum sgp_type sgp = nonblock? SGP_QUICK: SGP_CACHE; |
| 1255 | unsigned long size; |
| 1256 | |
| 1257 | size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 1258 | if (pgoff >= size || pgoff + (len >> PAGE_SHIFT) > size) |
| 1259 | return -EINVAL; |
| 1260 | |
| 1261 | while ((long) len > 0) { |
| 1262 | struct page *page = NULL; |
| 1263 | int err; |
| 1264 | /* |
| 1265 | * Will need changing if PAGE_CACHE_SIZE != PAGE_SIZE |
| 1266 | */ |
| 1267 | err = shmem_getpage(inode, pgoff, &page, sgp, NULL); |
| 1268 | if (err) |
| 1269 | return err; |
Paolo 'Blaisorblade' Giarrusso | d44ed4f | 2005-09-03 15:54:55 -0700 | [diff] [blame] | 1270 | /* Page may still be null, but only if nonblock was set. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1271 | if (page) { |
| 1272 | mark_page_accessed(page); |
| 1273 | err = install_page(mm, vma, addr, page, prot); |
| 1274 | if (err) { |
| 1275 | page_cache_release(page); |
| 1276 | return err; |
| 1277 | } |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 1278 | } else if (vma->vm_flags & VM_NONLINEAR) { |
Paolo 'Blaisorblade' Giarrusso | d44ed4f | 2005-09-03 15:54:55 -0700 | [diff] [blame] | 1279 | /* No page was found just because we can't read it in |
| 1280 | * now (being here implies nonblock != 0), but the page |
| 1281 | * may exist, so set the PTE to fault it in later. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1282 | err = install_file_pte(mm, vma, addr, pgoff, prot); |
| 1283 | if (err) |
| 1284 | return err; |
| 1285 | } |
| 1286 | |
| 1287 | len -= PAGE_SIZE; |
| 1288 | addr += PAGE_SIZE; |
| 1289 | pgoff++; |
| 1290 | } |
| 1291 | return 0; |
| 1292 | } |
| 1293 | |
| 1294 | #ifdef CONFIG_NUMA |
| 1295 | int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new) |
| 1296 | { |
| 1297 | struct inode *i = vma->vm_file->f_dentry->d_inode; |
| 1298 | return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new); |
| 1299 | } |
| 1300 | |
| 1301 | struct mempolicy * |
| 1302 | shmem_get_policy(struct vm_area_struct *vma, unsigned long addr) |
| 1303 | { |
| 1304 | struct inode *i = vma->vm_file->f_dentry->d_inode; |
| 1305 | unsigned long idx; |
| 1306 | |
| 1307 | idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; |
| 1308 | return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx); |
| 1309 | } |
| 1310 | #endif |
| 1311 | |
| 1312 | int shmem_lock(struct file *file, int lock, struct user_struct *user) |
| 1313 | { |
| 1314 | struct inode *inode = file->f_dentry->d_inode; |
| 1315 | struct shmem_inode_info *info = SHMEM_I(inode); |
| 1316 | int retval = -ENOMEM; |
| 1317 | |
| 1318 | spin_lock(&info->lock); |
| 1319 | if (lock && !(info->flags & VM_LOCKED)) { |
| 1320 | if (!user_shm_lock(inode->i_size, user)) |
| 1321 | goto out_nomem; |
| 1322 | info->flags |= VM_LOCKED; |
| 1323 | } |
| 1324 | if (!lock && (info->flags & VM_LOCKED) && user) { |
| 1325 | user_shm_unlock(inode->i_size, user); |
| 1326 | info->flags &= ~VM_LOCKED; |
| 1327 | } |
| 1328 | retval = 0; |
| 1329 | out_nomem: |
| 1330 | spin_unlock(&info->lock); |
| 1331 | return retval; |
| 1332 | } |
| 1333 | |
David Howells | b0e1519 | 2006-01-06 00:11:42 -0800 | [diff] [blame] | 1334 | int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1335 | { |
| 1336 | file_accessed(file); |
| 1337 | vma->vm_ops = &shmem_vm_ops; |
| 1338 | return 0; |
| 1339 | } |
| 1340 | |
| 1341 | static struct inode * |
| 1342 | shmem_get_inode(struct super_block *sb, int mode, dev_t dev) |
| 1343 | { |
| 1344 | struct inode *inode; |
| 1345 | struct shmem_inode_info *info; |
| 1346 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
| 1347 | |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 1348 | if (sbinfo->max_inodes) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1349 | spin_lock(&sbinfo->stat_lock); |
| 1350 | if (!sbinfo->free_inodes) { |
| 1351 | spin_unlock(&sbinfo->stat_lock); |
| 1352 | return NULL; |
| 1353 | } |
| 1354 | sbinfo->free_inodes--; |
| 1355 | spin_unlock(&sbinfo->stat_lock); |
| 1356 | } |
| 1357 | |
| 1358 | inode = new_inode(sb); |
| 1359 | if (inode) { |
| 1360 | inode->i_mode = mode; |
| 1361 | inode->i_uid = current->fsuid; |
| 1362 | inode->i_gid = current->fsgid; |
| 1363 | inode->i_blksize = PAGE_CACHE_SIZE; |
| 1364 | inode->i_blocks = 0; |
| 1365 | inode->i_mapping->a_ops = &shmem_aops; |
| 1366 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; |
| 1367 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
| 1368 | info = SHMEM_I(inode); |
| 1369 | memset(info, 0, (char *)inode - (char *)info); |
| 1370 | spin_lock_init(&info->lock); |
| 1371 | INIT_LIST_HEAD(&info->swaplist); |
| 1372 | |
| 1373 | switch (mode & S_IFMT) { |
| 1374 | default: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1375 | init_special_inode(inode, mode, dev); |
| 1376 | break; |
| 1377 | case S_IFREG: |
| 1378 | inode->i_op = &shmem_inode_operations; |
| 1379 | inode->i_fop = &shmem_file_operations; |
Robin Holt | 7339ff8 | 2006-01-14 13:20:48 -0800 | [diff] [blame] | 1380 | mpol_shared_policy_init(&info->policy, sbinfo->policy, |
| 1381 | &sbinfo->policy_nodes); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1382 | break; |
| 1383 | case S_IFDIR: |
| 1384 | inode->i_nlink++; |
| 1385 | /* Some things misbehave if size == 0 on a directory */ |
| 1386 | inode->i_size = 2 * BOGO_DIRENT_SIZE; |
| 1387 | inode->i_op = &shmem_dir_inode_operations; |
| 1388 | inode->i_fop = &simple_dir_operations; |
| 1389 | break; |
| 1390 | case S_IFLNK: |
| 1391 | /* |
| 1392 | * Must not load anything in the rbtree, |
| 1393 | * mpol_free_shared_policy will not be called. |
| 1394 | */ |
Robin Holt | 7339ff8 | 2006-01-14 13:20:48 -0800 | [diff] [blame] | 1395 | mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, |
| 1396 | NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1397 | break; |
| 1398 | } |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 1399 | } else if (sbinfo->max_inodes) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1400 | spin_lock(&sbinfo->stat_lock); |
| 1401 | sbinfo->free_inodes++; |
| 1402 | spin_unlock(&sbinfo->stat_lock); |
| 1403 | } |
| 1404 | return inode; |
| 1405 | } |
| 1406 | |
| 1407 | #ifdef CONFIG_TMPFS |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1408 | static struct inode_operations shmem_symlink_inode_operations; |
| 1409 | static struct inode_operations shmem_symlink_inline_operations; |
| 1410 | |
| 1411 | /* |
| 1412 | * Normally tmpfs makes no use of shmem_prepare_write, but it |
| 1413 | * lets a tmpfs file be used read-write below the loop driver. |
| 1414 | */ |
| 1415 | static int |
| 1416 | shmem_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to) |
| 1417 | { |
| 1418 | struct inode *inode = page->mapping->host; |
| 1419 | return shmem_getpage(inode, page->index, &page, SGP_WRITE, NULL); |
| 1420 | } |
| 1421 | |
| 1422 | static ssize_t |
| 1423 | shmem_file_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) |
| 1424 | { |
| 1425 | struct inode *inode = file->f_dentry->d_inode; |
| 1426 | loff_t pos; |
| 1427 | unsigned long written; |
| 1428 | ssize_t err; |
| 1429 | |
| 1430 | if ((ssize_t) count < 0) |
| 1431 | return -EINVAL; |
| 1432 | |
| 1433 | if (!access_ok(VERIFY_READ, buf, count)) |
| 1434 | return -EFAULT; |
| 1435 | |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 1436 | mutex_lock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1437 | |
| 1438 | pos = *ppos; |
| 1439 | written = 0; |
| 1440 | |
| 1441 | err = generic_write_checks(file, &pos, &count, 0); |
| 1442 | if (err || !count) |
| 1443 | goto out; |
| 1444 | |
| 1445 | err = remove_suid(file->f_dentry); |
| 1446 | if (err) |
| 1447 | goto out; |
| 1448 | |
| 1449 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; |
| 1450 | |
| 1451 | do { |
| 1452 | struct page *page = NULL; |
| 1453 | unsigned long bytes, index, offset; |
| 1454 | char *kaddr; |
| 1455 | int left; |
| 1456 | |
| 1457 | offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */ |
| 1458 | index = pos >> PAGE_CACHE_SHIFT; |
| 1459 | bytes = PAGE_CACHE_SIZE - offset; |
| 1460 | if (bytes > count) |
| 1461 | bytes = count; |
| 1462 | |
| 1463 | /* |
| 1464 | * We don't hold page lock across copy from user - |
| 1465 | * what would it guard against? - so no deadlock here. |
| 1466 | * But it still may be a good idea to prefault below. |
| 1467 | */ |
| 1468 | |
| 1469 | err = shmem_getpage(inode, index, &page, SGP_WRITE, NULL); |
| 1470 | if (err) |
| 1471 | break; |
| 1472 | |
| 1473 | left = bytes; |
| 1474 | if (PageHighMem(page)) { |
| 1475 | volatile unsigned char dummy; |
| 1476 | __get_user(dummy, buf); |
| 1477 | __get_user(dummy, buf + bytes - 1); |
| 1478 | |
| 1479 | kaddr = kmap_atomic(page, KM_USER0); |
| 1480 | left = __copy_from_user_inatomic(kaddr + offset, |
| 1481 | buf, bytes); |
| 1482 | kunmap_atomic(kaddr, KM_USER0); |
| 1483 | } |
| 1484 | if (left) { |
| 1485 | kaddr = kmap(page); |
| 1486 | left = __copy_from_user(kaddr + offset, buf, bytes); |
| 1487 | kunmap(page); |
| 1488 | } |
| 1489 | |
| 1490 | written += bytes; |
| 1491 | count -= bytes; |
| 1492 | pos += bytes; |
| 1493 | buf += bytes; |
| 1494 | if (pos > inode->i_size) |
| 1495 | i_size_write(inode, pos); |
| 1496 | |
| 1497 | flush_dcache_page(page); |
| 1498 | set_page_dirty(page); |
| 1499 | mark_page_accessed(page); |
| 1500 | page_cache_release(page); |
| 1501 | |
| 1502 | if (left) { |
| 1503 | pos -= left; |
| 1504 | written -= left; |
| 1505 | err = -EFAULT; |
| 1506 | break; |
| 1507 | } |
| 1508 | |
| 1509 | /* |
| 1510 | * Our dirty pages are not counted in nr_dirty, |
| 1511 | * and we do not attempt to balance dirty pages. |
| 1512 | */ |
| 1513 | |
| 1514 | cond_resched(); |
| 1515 | } while (count); |
| 1516 | |
| 1517 | *ppos = pos; |
| 1518 | if (written) |
| 1519 | err = written; |
| 1520 | out: |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 1521 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1522 | return err; |
| 1523 | } |
| 1524 | |
| 1525 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) |
| 1526 | { |
| 1527 | struct inode *inode = filp->f_dentry->d_inode; |
| 1528 | struct address_space *mapping = inode->i_mapping; |
| 1529 | unsigned long index, offset; |
| 1530 | |
| 1531 | index = *ppos >> PAGE_CACHE_SHIFT; |
| 1532 | offset = *ppos & ~PAGE_CACHE_MASK; |
| 1533 | |
| 1534 | for (;;) { |
| 1535 | struct page *page = NULL; |
| 1536 | unsigned long end_index, nr, ret; |
| 1537 | loff_t i_size = i_size_read(inode); |
| 1538 | |
| 1539 | end_index = i_size >> PAGE_CACHE_SHIFT; |
| 1540 | if (index > end_index) |
| 1541 | break; |
| 1542 | if (index == end_index) { |
| 1543 | nr = i_size & ~PAGE_CACHE_MASK; |
| 1544 | if (nr <= offset) |
| 1545 | break; |
| 1546 | } |
| 1547 | |
| 1548 | desc->error = shmem_getpage(inode, index, &page, SGP_READ, NULL); |
| 1549 | if (desc->error) { |
| 1550 | if (desc->error == -EINVAL) |
| 1551 | desc->error = 0; |
| 1552 | break; |
| 1553 | } |
| 1554 | |
| 1555 | /* |
| 1556 | * We must evaluate after, since reads (unlike writes) |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 1557 | * are called without i_mutex protection against truncate |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1558 | */ |
| 1559 | nr = PAGE_CACHE_SIZE; |
| 1560 | i_size = i_size_read(inode); |
| 1561 | end_index = i_size >> PAGE_CACHE_SHIFT; |
| 1562 | if (index == end_index) { |
| 1563 | nr = i_size & ~PAGE_CACHE_MASK; |
| 1564 | if (nr <= offset) { |
| 1565 | if (page) |
| 1566 | page_cache_release(page); |
| 1567 | break; |
| 1568 | } |
| 1569 | } |
| 1570 | nr -= offset; |
| 1571 | |
| 1572 | if (page) { |
| 1573 | /* |
| 1574 | * If users can be writing to this page using arbitrary |
| 1575 | * virtual addresses, take care about potential aliasing |
| 1576 | * before reading the page on the kernel side. |
| 1577 | */ |
| 1578 | if (mapping_writably_mapped(mapping)) |
| 1579 | flush_dcache_page(page); |
| 1580 | /* |
| 1581 | * Mark the page accessed if we read the beginning. |
| 1582 | */ |
| 1583 | if (!offset) |
| 1584 | mark_page_accessed(page); |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 1585 | } else { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1586 | page = ZERO_PAGE(0); |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 1587 | page_cache_get(page); |
| 1588 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1589 | |
| 1590 | /* |
| 1591 | * Ok, we have the page, and it's up-to-date, so |
| 1592 | * now we can copy it to user space... |
| 1593 | * |
| 1594 | * The actor routine returns how many bytes were actually used.. |
| 1595 | * NOTE! This may not be the same as how much of a user buffer |
| 1596 | * we filled up (we may be padding etc), so we can only update |
| 1597 | * "pos" here (the actor routine has to update the user buffer |
| 1598 | * pointers and the remaining count). |
| 1599 | */ |
| 1600 | ret = actor(desc, page, offset, nr); |
| 1601 | offset += ret; |
| 1602 | index += offset >> PAGE_CACHE_SHIFT; |
| 1603 | offset &= ~PAGE_CACHE_MASK; |
| 1604 | |
| 1605 | page_cache_release(page); |
| 1606 | if (ret != nr || !desc->count) |
| 1607 | break; |
| 1608 | |
| 1609 | cond_resched(); |
| 1610 | } |
| 1611 | |
| 1612 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; |
| 1613 | file_accessed(filp); |
| 1614 | } |
| 1615 | |
| 1616 | static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) |
| 1617 | { |
| 1618 | read_descriptor_t desc; |
| 1619 | |
| 1620 | if ((ssize_t) count < 0) |
| 1621 | return -EINVAL; |
| 1622 | if (!access_ok(VERIFY_WRITE, buf, count)) |
| 1623 | return -EFAULT; |
| 1624 | if (!count) |
| 1625 | return 0; |
| 1626 | |
| 1627 | desc.written = 0; |
| 1628 | desc.count = count; |
| 1629 | desc.arg.buf = buf; |
| 1630 | desc.error = 0; |
| 1631 | |
| 1632 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); |
| 1633 | if (desc.written) |
| 1634 | return desc.written; |
| 1635 | return desc.error; |
| 1636 | } |
| 1637 | |
| 1638 | static ssize_t shmem_file_sendfile(struct file *in_file, loff_t *ppos, |
| 1639 | size_t count, read_actor_t actor, void *target) |
| 1640 | { |
| 1641 | read_descriptor_t desc; |
| 1642 | |
| 1643 | if (!count) |
| 1644 | return 0; |
| 1645 | |
| 1646 | desc.written = 0; |
| 1647 | desc.count = count; |
| 1648 | desc.arg.data = target; |
| 1649 | desc.error = 0; |
| 1650 | |
| 1651 | do_shmem_file_read(in_file, ppos, &desc, actor); |
| 1652 | if (desc.written) |
| 1653 | return desc.written; |
| 1654 | return desc.error; |
| 1655 | } |
| 1656 | |
| 1657 | static int shmem_statfs(struct super_block *sb, struct kstatfs *buf) |
| 1658 | { |
| 1659 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
| 1660 | |
| 1661 | buf->f_type = TMPFS_MAGIC; |
| 1662 | buf->f_bsize = PAGE_CACHE_SIZE; |
| 1663 | buf->f_namelen = NAME_MAX; |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 1664 | spin_lock(&sbinfo->stat_lock); |
| 1665 | if (sbinfo->max_blocks) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1666 | buf->f_blocks = sbinfo->max_blocks; |
| 1667 | buf->f_bavail = buf->f_bfree = sbinfo->free_blocks; |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 1668 | } |
| 1669 | if (sbinfo->max_inodes) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1670 | buf->f_files = sbinfo->max_inodes; |
| 1671 | buf->f_ffree = sbinfo->free_inodes; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1672 | } |
| 1673 | /* else leave those fields 0 like simple_statfs */ |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 1674 | spin_unlock(&sbinfo->stat_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1675 | return 0; |
| 1676 | } |
| 1677 | |
| 1678 | /* |
| 1679 | * File creation. Allocate an inode, and we're done.. |
| 1680 | */ |
| 1681 | static int |
| 1682 | shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) |
| 1683 | { |
| 1684 | struct inode *inode = shmem_get_inode(dir->i_sb, mode, dev); |
| 1685 | int error = -ENOSPC; |
| 1686 | |
| 1687 | if (inode) { |
Stephen Smalley | 570bc1c | 2005-09-09 13:01:43 -0700 | [diff] [blame] | 1688 | error = security_inode_init_security(inode, dir, NULL, NULL, |
| 1689 | NULL); |
| 1690 | if (error) { |
| 1691 | if (error != -EOPNOTSUPP) { |
| 1692 | iput(inode); |
| 1693 | return error; |
| 1694 | } |
| 1695 | error = 0; |
| 1696 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1697 | if (dir->i_mode & S_ISGID) { |
| 1698 | inode->i_gid = dir->i_gid; |
| 1699 | if (S_ISDIR(mode)) |
| 1700 | inode->i_mode |= S_ISGID; |
| 1701 | } |
| 1702 | dir->i_size += BOGO_DIRENT_SIZE; |
| 1703 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
| 1704 | d_instantiate(dentry, inode); |
| 1705 | dget(dentry); /* Extra count - pin the dentry in core */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1706 | } |
| 1707 | return error; |
| 1708 | } |
| 1709 | |
| 1710 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode) |
| 1711 | { |
| 1712 | int error; |
| 1713 | |
| 1714 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) |
| 1715 | return error; |
| 1716 | dir->i_nlink++; |
| 1717 | return 0; |
| 1718 | } |
| 1719 | |
| 1720 | static int shmem_create(struct inode *dir, struct dentry *dentry, int mode, |
| 1721 | struct nameidata *nd) |
| 1722 | { |
| 1723 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); |
| 1724 | } |
| 1725 | |
| 1726 | /* |
| 1727 | * Link a file.. |
| 1728 | */ |
| 1729 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) |
| 1730 | { |
| 1731 | struct inode *inode = old_dentry->d_inode; |
| 1732 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
| 1733 | |
| 1734 | /* |
| 1735 | * No ordinary (disk based) filesystem counts links as inodes; |
| 1736 | * but each new link needs a new dentry, pinning lowmem, and |
| 1737 | * tmpfs dentries cannot be pruned until they are unlinked. |
| 1738 | */ |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 1739 | if (sbinfo->max_inodes) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1740 | spin_lock(&sbinfo->stat_lock); |
| 1741 | if (!sbinfo->free_inodes) { |
| 1742 | spin_unlock(&sbinfo->stat_lock); |
| 1743 | return -ENOSPC; |
| 1744 | } |
| 1745 | sbinfo->free_inodes--; |
| 1746 | spin_unlock(&sbinfo->stat_lock); |
| 1747 | } |
| 1748 | |
| 1749 | dir->i_size += BOGO_DIRENT_SIZE; |
| 1750 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
| 1751 | inode->i_nlink++; |
| 1752 | atomic_inc(&inode->i_count); /* New dentry reference */ |
| 1753 | dget(dentry); /* Extra pinning count for the created dentry */ |
| 1754 | d_instantiate(dentry, inode); |
| 1755 | return 0; |
| 1756 | } |
| 1757 | |
| 1758 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) |
| 1759 | { |
| 1760 | struct inode *inode = dentry->d_inode; |
| 1761 | |
| 1762 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) { |
| 1763 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 1764 | if (sbinfo->max_inodes) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1765 | spin_lock(&sbinfo->stat_lock); |
| 1766 | sbinfo->free_inodes++; |
| 1767 | spin_unlock(&sbinfo->stat_lock); |
| 1768 | } |
| 1769 | } |
| 1770 | |
| 1771 | dir->i_size -= BOGO_DIRENT_SIZE; |
| 1772 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
| 1773 | inode->i_nlink--; |
| 1774 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
| 1775 | return 0; |
| 1776 | } |
| 1777 | |
| 1778 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) |
| 1779 | { |
| 1780 | if (!simple_empty(dentry)) |
| 1781 | return -ENOTEMPTY; |
| 1782 | |
Sergey Vlasov | 86bc843 | 2006-06-12 21:53:23 +0100 | [diff] [blame] | 1783 | dentry->d_inode->i_nlink--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1784 | dir->i_nlink--; |
| 1785 | return shmem_unlink(dir, dentry); |
| 1786 | } |
| 1787 | |
| 1788 | /* |
| 1789 | * The VFS layer already does all the dentry stuff for rename, |
| 1790 | * we just have to decrement the usage count for the target if |
| 1791 | * it exists so that the VFS layer correctly free's it when it |
| 1792 | * gets overwritten. |
| 1793 | */ |
| 1794 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) |
| 1795 | { |
| 1796 | struct inode *inode = old_dentry->d_inode; |
| 1797 | int they_are_dirs = S_ISDIR(inode->i_mode); |
| 1798 | |
| 1799 | if (!simple_empty(new_dentry)) |
| 1800 | return -ENOTEMPTY; |
| 1801 | |
| 1802 | if (new_dentry->d_inode) { |
| 1803 | (void) shmem_unlink(new_dir, new_dentry); |
| 1804 | if (they_are_dirs) |
| 1805 | old_dir->i_nlink--; |
| 1806 | } else if (they_are_dirs) { |
| 1807 | old_dir->i_nlink--; |
| 1808 | new_dir->i_nlink++; |
| 1809 | } |
| 1810 | |
| 1811 | old_dir->i_size -= BOGO_DIRENT_SIZE; |
| 1812 | new_dir->i_size += BOGO_DIRENT_SIZE; |
| 1813 | old_dir->i_ctime = old_dir->i_mtime = |
| 1814 | new_dir->i_ctime = new_dir->i_mtime = |
| 1815 | inode->i_ctime = CURRENT_TIME; |
| 1816 | return 0; |
| 1817 | } |
| 1818 | |
| 1819 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) |
| 1820 | { |
| 1821 | int error; |
| 1822 | int len; |
| 1823 | struct inode *inode; |
| 1824 | struct page *page = NULL; |
| 1825 | char *kaddr; |
| 1826 | struct shmem_inode_info *info; |
| 1827 | |
| 1828 | len = strlen(symname) + 1; |
| 1829 | if (len > PAGE_CACHE_SIZE) |
| 1830 | return -ENAMETOOLONG; |
| 1831 | |
| 1832 | inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0); |
| 1833 | if (!inode) |
| 1834 | return -ENOSPC; |
| 1835 | |
Stephen Smalley | 570bc1c | 2005-09-09 13:01:43 -0700 | [diff] [blame] | 1836 | error = security_inode_init_security(inode, dir, NULL, NULL, |
| 1837 | NULL); |
| 1838 | if (error) { |
| 1839 | if (error != -EOPNOTSUPP) { |
| 1840 | iput(inode); |
| 1841 | return error; |
| 1842 | } |
| 1843 | error = 0; |
| 1844 | } |
| 1845 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1846 | info = SHMEM_I(inode); |
| 1847 | inode->i_size = len-1; |
| 1848 | if (len <= (char *)inode - (char *)info) { |
| 1849 | /* do it inline */ |
| 1850 | memcpy(info, symname, len); |
| 1851 | inode->i_op = &shmem_symlink_inline_operations; |
| 1852 | } else { |
| 1853 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); |
| 1854 | if (error) { |
| 1855 | iput(inode); |
| 1856 | return error; |
| 1857 | } |
| 1858 | inode->i_op = &shmem_symlink_inode_operations; |
| 1859 | kaddr = kmap_atomic(page, KM_USER0); |
| 1860 | memcpy(kaddr, symname, len); |
| 1861 | kunmap_atomic(kaddr, KM_USER0); |
| 1862 | set_page_dirty(page); |
| 1863 | page_cache_release(page); |
| 1864 | } |
| 1865 | if (dir->i_mode & S_ISGID) |
| 1866 | inode->i_gid = dir->i_gid; |
| 1867 | dir->i_size += BOGO_DIRENT_SIZE; |
| 1868 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
| 1869 | d_instantiate(dentry, inode); |
| 1870 | dget(dentry); |
| 1871 | return 0; |
| 1872 | } |
| 1873 | |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 1874 | static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1875 | { |
| 1876 | nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode)); |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 1877 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1878 | } |
| 1879 | |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 1880 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1881 | { |
| 1882 | struct page *page = NULL; |
| 1883 | int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); |
| 1884 | nd_set_link(nd, res ? ERR_PTR(res) : kmap(page)); |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 1885 | return page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1886 | } |
| 1887 | |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 1888 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1889 | { |
| 1890 | if (!IS_ERR(nd_get_link(nd))) { |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 1891 | struct page *page = cookie; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1892 | kunmap(page); |
| 1893 | mark_page_accessed(page); |
| 1894 | page_cache_release(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1895 | } |
| 1896 | } |
| 1897 | |
| 1898 | static struct inode_operations shmem_symlink_inline_operations = { |
| 1899 | .readlink = generic_readlink, |
| 1900 | .follow_link = shmem_follow_link_inline, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1901 | }; |
| 1902 | |
| 1903 | static struct inode_operations shmem_symlink_inode_operations = { |
| 1904 | .truncate = shmem_truncate, |
| 1905 | .readlink = generic_readlink, |
| 1906 | .follow_link = shmem_follow_link, |
| 1907 | .put_link = shmem_put_link, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1908 | }; |
| 1909 | |
Robin Holt | 7339ff8 | 2006-01-14 13:20:48 -0800 | [diff] [blame] | 1910 | static int shmem_parse_options(char *options, int *mode, uid_t *uid, |
| 1911 | gid_t *gid, unsigned long *blocks, unsigned long *inodes, |
| 1912 | int *policy, nodemask_t *policy_nodes) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1913 | { |
| 1914 | char *this_char, *value, *rest; |
| 1915 | |
Hugh Dickins | b00dc3a | 2006-02-21 23:49:47 +0000 | [diff] [blame] | 1916 | while (options != NULL) { |
| 1917 | this_char = options; |
| 1918 | for (;;) { |
| 1919 | /* |
| 1920 | * NUL-terminate this option: unfortunately, |
| 1921 | * mount options form a comma-separated list, |
| 1922 | * but mpol's nodelist may also contain commas. |
| 1923 | */ |
| 1924 | options = strchr(options, ','); |
| 1925 | if (options == NULL) |
| 1926 | break; |
| 1927 | options++; |
| 1928 | if (!isdigit(*options)) { |
| 1929 | options[-1] = '\0'; |
| 1930 | break; |
| 1931 | } |
| 1932 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1933 | if (!*this_char) |
| 1934 | continue; |
| 1935 | if ((value = strchr(this_char,'=')) != NULL) { |
| 1936 | *value++ = 0; |
| 1937 | } else { |
| 1938 | printk(KERN_ERR |
| 1939 | "tmpfs: No value for mount option '%s'\n", |
| 1940 | this_char); |
| 1941 | return 1; |
| 1942 | } |
| 1943 | |
| 1944 | if (!strcmp(this_char,"size")) { |
| 1945 | unsigned long long size; |
| 1946 | size = memparse(value,&rest); |
| 1947 | if (*rest == '%') { |
| 1948 | size <<= PAGE_SHIFT; |
| 1949 | size *= totalram_pages; |
| 1950 | do_div(size, 100); |
| 1951 | rest++; |
| 1952 | } |
| 1953 | if (*rest) |
| 1954 | goto bad_val; |
| 1955 | *blocks = size >> PAGE_CACHE_SHIFT; |
| 1956 | } else if (!strcmp(this_char,"nr_blocks")) { |
| 1957 | *blocks = memparse(value,&rest); |
| 1958 | if (*rest) |
| 1959 | goto bad_val; |
| 1960 | } else if (!strcmp(this_char,"nr_inodes")) { |
| 1961 | *inodes = memparse(value,&rest); |
| 1962 | if (*rest) |
| 1963 | goto bad_val; |
| 1964 | } else if (!strcmp(this_char,"mode")) { |
| 1965 | if (!mode) |
| 1966 | continue; |
| 1967 | *mode = simple_strtoul(value,&rest,8); |
| 1968 | if (*rest) |
| 1969 | goto bad_val; |
| 1970 | } else if (!strcmp(this_char,"uid")) { |
| 1971 | if (!uid) |
| 1972 | continue; |
| 1973 | *uid = simple_strtoul(value,&rest,0); |
| 1974 | if (*rest) |
| 1975 | goto bad_val; |
| 1976 | } else if (!strcmp(this_char,"gid")) { |
| 1977 | if (!gid) |
| 1978 | continue; |
| 1979 | *gid = simple_strtoul(value,&rest,0); |
| 1980 | if (*rest) |
| 1981 | goto bad_val; |
Robin Holt | 7339ff8 | 2006-01-14 13:20:48 -0800 | [diff] [blame] | 1982 | } else if (!strcmp(this_char,"mpol")) { |
Hugh Dickins | b00dc3a | 2006-02-21 23:49:47 +0000 | [diff] [blame] | 1983 | if (shmem_parse_mpol(value,policy,policy_nodes)) |
Robin Holt | 7339ff8 | 2006-01-14 13:20:48 -0800 | [diff] [blame] | 1984 | goto bad_val; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1985 | } else { |
| 1986 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", |
| 1987 | this_char); |
| 1988 | return 1; |
| 1989 | } |
| 1990 | } |
| 1991 | return 0; |
| 1992 | |
| 1993 | bad_val: |
| 1994 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", |
| 1995 | value, this_char); |
| 1996 | return 1; |
| 1997 | |
| 1998 | } |
| 1999 | |
| 2000 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) |
| 2001 | { |
| 2002 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 2003 | unsigned long max_blocks = sbinfo->max_blocks; |
| 2004 | unsigned long max_inodes = sbinfo->max_inodes; |
Robin Holt | 7339ff8 | 2006-01-14 13:20:48 -0800 | [diff] [blame] | 2005 | int policy = sbinfo->policy; |
| 2006 | nodemask_t policy_nodes = sbinfo->policy_nodes; |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 2007 | unsigned long blocks; |
| 2008 | unsigned long inodes; |
| 2009 | int error = -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2010 | |
Robin Holt | 7339ff8 | 2006-01-14 13:20:48 -0800 | [diff] [blame] | 2011 | if (shmem_parse_options(data, NULL, NULL, NULL, &max_blocks, |
| 2012 | &max_inodes, &policy, &policy_nodes)) |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 2013 | return error; |
| 2014 | |
| 2015 | spin_lock(&sbinfo->stat_lock); |
| 2016 | blocks = sbinfo->max_blocks - sbinfo->free_blocks; |
| 2017 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; |
| 2018 | if (max_blocks < blocks) |
| 2019 | goto out; |
| 2020 | if (max_inodes < inodes) |
| 2021 | goto out; |
| 2022 | /* |
| 2023 | * Those tests also disallow limited->unlimited while any are in |
| 2024 | * use, so i_blocks will always be zero when max_blocks is zero; |
| 2025 | * but we must separately disallow unlimited->limited, because |
| 2026 | * in that case we have no record of how much is already in use. |
| 2027 | */ |
| 2028 | if (max_blocks && !sbinfo->max_blocks) |
| 2029 | goto out; |
| 2030 | if (max_inodes && !sbinfo->max_inodes) |
| 2031 | goto out; |
| 2032 | |
| 2033 | error = 0; |
| 2034 | sbinfo->max_blocks = max_blocks; |
| 2035 | sbinfo->free_blocks = max_blocks - blocks; |
| 2036 | sbinfo->max_inodes = max_inodes; |
| 2037 | sbinfo->free_inodes = max_inodes - inodes; |
Robin Holt | 7339ff8 | 2006-01-14 13:20:48 -0800 | [diff] [blame] | 2038 | sbinfo->policy = policy; |
| 2039 | sbinfo->policy_nodes = policy_nodes; |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 2040 | out: |
| 2041 | spin_unlock(&sbinfo->stat_lock); |
| 2042 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2043 | } |
| 2044 | #endif |
| 2045 | |
| 2046 | static void shmem_put_super(struct super_block *sb) |
| 2047 | { |
| 2048 | kfree(sb->s_fs_info); |
| 2049 | sb->s_fs_info = NULL; |
| 2050 | } |
| 2051 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2052 | static int shmem_fill_super(struct super_block *sb, |
| 2053 | void *data, int silent) |
| 2054 | { |
| 2055 | struct inode *inode; |
| 2056 | struct dentry *root; |
| 2057 | int mode = S_IRWXUGO | S_ISVTX; |
| 2058 | uid_t uid = current->fsuid; |
| 2059 | gid_t gid = current->fsgid; |
| 2060 | int err = -ENOMEM; |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 2061 | struct shmem_sb_info *sbinfo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2062 | unsigned long blocks = 0; |
| 2063 | unsigned long inodes = 0; |
Robin Holt | 7339ff8 | 2006-01-14 13:20:48 -0800 | [diff] [blame] | 2064 | int policy = MPOL_DEFAULT; |
| 2065 | nodemask_t policy_nodes = node_online_map; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2066 | |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 2067 | #ifdef CONFIG_TMPFS |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2068 | /* |
| 2069 | * Per default we only allow half of the physical ram per |
| 2070 | * tmpfs instance, limiting inodes to one per page of lowmem; |
| 2071 | * but the internal instance is left unlimited. |
| 2072 | */ |
| 2073 | if (!(sb->s_flags & MS_NOUSER)) { |
| 2074 | blocks = totalram_pages / 2; |
| 2075 | inodes = totalram_pages - totalhigh_pages; |
| 2076 | if (inodes > blocks) |
| 2077 | inodes = blocks; |
Robin Holt | 7339ff8 | 2006-01-14 13:20:48 -0800 | [diff] [blame] | 2078 | if (shmem_parse_options(data, &mode, &uid, &gid, &blocks, |
| 2079 | &inodes, &policy, &policy_nodes)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2080 | return -EINVAL; |
| 2081 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2082 | #else |
| 2083 | sb->s_flags |= MS_NOUSER; |
| 2084 | #endif |
| 2085 | |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 2086 | /* Round up to L1_CACHE_BYTES to resist false sharing */ |
| 2087 | sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info), |
| 2088 | L1_CACHE_BYTES), GFP_KERNEL); |
| 2089 | if (!sbinfo) |
| 2090 | return -ENOMEM; |
| 2091 | |
| 2092 | spin_lock_init(&sbinfo->stat_lock); |
| 2093 | sbinfo->max_blocks = blocks; |
| 2094 | sbinfo->free_blocks = blocks; |
| 2095 | sbinfo->max_inodes = inodes; |
| 2096 | sbinfo->free_inodes = inodes; |
Robin Holt | 7339ff8 | 2006-01-14 13:20:48 -0800 | [diff] [blame] | 2097 | sbinfo->policy = policy; |
| 2098 | sbinfo->policy_nodes = policy_nodes; |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 2099 | |
| 2100 | sb->s_fs_info = sbinfo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2101 | sb->s_maxbytes = SHMEM_MAX_BYTES; |
| 2102 | sb->s_blocksize = PAGE_CACHE_SIZE; |
| 2103 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; |
| 2104 | sb->s_magic = TMPFS_MAGIC; |
| 2105 | sb->s_op = &shmem_ops; |
Robin H. Johnson | cfd95a9 | 2006-06-12 21:50:25 +0100 | [diff] [blame] | 2106 | sb->s_time_gran = 1; |
Hugh Dickins | 0edd73b | 2005-06-21 17:15:04 -0700 | [diff] [blame] | 2107 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2108 | inode = shmem_get_inode(sb, S_IFDIR | mode, 0); |
| 2109 | if (!inode) |
| 2110 | goto failed; |
| 2111 | inode->i_uid = uid; |
| 2112 | inode->i_gid = gid; |
| 2113 | root = d_alloc_root(inode); |
| 2114 | if (!root) |
| 2115 | goto failed_iput; |
| 2116 | sb->s_root = root; |
| 2117 | return 0; |
| 2118 | |
| 2119 | failed_iput: |
| 2120 | iput(inode); |
| 2121 | failed: |
| 2122 | shmem_put_super(sb); |
| 2123 | return err; |
| 2124 | } |
| 2125 | |
Pekka Enberg | fcc234f | 2006-03-22 00:08:13 -0800 | [diff] [blame] | 2126 | static struct kmem_cache *shmem_inode_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2127 | |
| 2128 | static struct inode *shmem_alloc_inode(struct super_block *sb) |
| 2129 | { |
| 2130 | struct shmem_inode_info *p; |
| 2131 | p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, SLAB_KERNEL); |
| 2132 | if (!p) |
| 2133 | return NULL; |
| 2134 | return &p->vfs_inode; |
| 2135 | } |
| 2136 | |
| 2137 | static void shmem_destroy_inode(struct inode *inode) |
| 2138 | { |
| 2139 | if ((inode->i_mode & S_IFMT) == S_IFREG) { |
| 2140 | /* only struct inode is valid if it's an inline symlink */ |
| 2141 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); |
| 2142 | } |
| 2143 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); |
| 2144 | } |
| 2145 | |
Pekka Enberg | fcc234f | 2006-03-22 00:08:13 -0800 | [diff] [blame] | 2146 | static void init_once(void *foo, struct kmem_cache *cachep, |
| 2147 | unsigned long flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2148 | { |
| 2149 | struct shmem_inode_info *p = (struct shmem_inode_info *) foo; |
| 2150 | |
| 2151 | if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == |
| 2152 | SLAB_CTOR_CONSTRUCTOR) { |
| 2153 | inode_init_once(&p->vfs_inode); |
| 2154 | } |
| 2155 | } |
| 2156 | |
| 2157 | static int init_inodecache(void) |
| 2158 | { |
| 2159 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", |
| 2160 | sizeof(struct shmem_inode_info), |
| 2161 | 0, 0, init_once, NULL); |
| 2162 | if (shmem_inode_cachep == NULL) |
| 2163 | return -ENOMEM; |
| 2164 | return 0; |
| 2165 | } |
| 2166 | |
| 2167 | static void destroy_inodecache(void) |
| 2168 | { |
| 2169 | if (kmem_cache_destroy(shmem_inode_cachep)) |
| 2170 | printk(KERN_INFO "shmem_inode_cache: not all structures were freed\n"); |
| 2171 | } |
| 2172 | |
| 2173 | static struct address_space_operations shmem_aops = { |
| 2174 | .writepage = shmem_writepage, |
| 2175 | .set_page_dirty = __set_page_dirty_nobuffers, |
| 2176 | #ifdef CONFIG_TMPFS |
| 2177 | .prepare_write = shmem_prepare_write, |
| 2178 | .commit_write = simple_commit_write, |
| 2179 | #endif |
Lee Schermerhorn | 304dbdb | 2006-04-22 02:35:48 -0700 | [diff] [blame] | 2180 | .migratepage = migrate_page, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2181 | }; |
| 2182 | |
| 2183 | static struct file_operations shmem_file_operations = { |
| 2184 | .mmap = shmem_mmap, |
| 2185 | #ifdef CONFIG_TMPFS |
| 2186 | .llseek = generic_file_llseek, |
| 2187 | .read = shmem_file_read, |
| 2188 | .write = shmem_file_write, |
| 2189 | .fsync = simple_sync_file, |
| 2190 | .sendfile = shmem_file_sendfile, |
| 2191 | #endif |
| 2192 | }; |
| 2193 | |
| 2194 | static struct inode_operations shmem_inode_operations = { |
| 2195 | .truncate = shmem_truncate, |
| 2196 | .setattr = shmem_notify_change, |
Badari Pulavarty | f6b3ec2 | 2006-01-06 00:10:38 -0800 | [diff] [blame] | 2197 | .truncate_range = shmem_truncate_range, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2198 | }; |
| 2199 | |
| 2200 | static struct inode_operations shmem_dir_inode_operations = { |
| 2201 | #ifdef CONFIG_TMPFS |
| 2202 | .create = shmem_create, |
| 2203 | .lookup = simple_lookup, |
| 2204 | .link = shmem_link, |
| 2205 | .unlink = shmem_unlink, |
| 2206 | .symlink = shmem_symlink, |
| 2207 | .mkdir = shmem_mkdir, |
| 2208 | .rmdir = shmem_rmdir, |
| 2209 | .mknod = shmem_mknod, |
| 2210 | .rename = shmem_rename, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2211 | #endif |
| 2212 | }; |
| 2213 | |
| 2214 | static struct super_operations shmem_ops = { |
| 2215 | .alloc_inode = shmem_alloc_inode, |
| 2216 | .destroy_inode = shmem_destroy_inode, |
| 2217 | #ifdef CONFIG_TMPFS |
| 2218 | .statfs = shmem_statfs, |
| 2219 | .remount_fs = shmem_remount_fs, |
| 2220 | #endif |
| 2221 | .delete_inode = shmem_delete_inode, |
| 2222 | .drop_inode = generic_delete_inode, |
| 2223 | .put_super = shmem_put_super, |
| 2224 | }; |
| 2225 | |
| 2226 | static struct vm_operations_struct shmem_vm_ops = { |
| 2227 | .nopage = shmem_nopage, |
| 2228 | .populate = shmem_populate, |
| 2229 | #ifdef CONFIG_NUMA |
| 2230 | .set_policy = shmem_set_policy, |
| 2231 | .get_policy = shmem_get_policy, |
| 2232 | #endif |
| 2233 | }; |
| 2234 | |
| 2235 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2236 | static struct super_block *shmem_get_sb(struct file_system_type *fs_type, |
| 2237 | int flags, const char *dev_name, void *data) |
| 2238 | { |
| 2239 | return get_sb_nodev(fs_type, flags, data, shmem_fill_super); |
| 2240 | } |
| 2241 | |
| 2242 | static struct file_system_type tmpfs_fs_type = { |
| 2243 | .owner = THIS_MODULE, |
| 2244 | .name = "tmpfs", |
| 2245 | .get_sb = shmem_get_sb, |
| 2246 | .kill_sb = kill_litter_super, |
| 2247 | }; |
| 2248 | static struct vfsmount *shm_mnt; |
| 2249 | |
| 2250 | static int __init init_tmpfs(void) |
| 2251 | { |
| 2252 | int error; |
| 2253 | |
| 2254 | error = init_inodecache(); |
| 2255 | if (error) |
| 2256 | goto out3; |
| 2257 | |
| 2258 | error = register_filesystem(&tmpfs_fs_type); |
| 2259 | if (error) { |
| 2260 | printk(KERN_ERR "Could not register tmpfs\n"); |
| 2261 | goto out2; |
| 2262 | } |
| 2263 | #ifdef CONFIG_TMPFS |
| 2264 | devfs_mk_dir("shm"); |
| 2265 | #endif |
| 2266 | shm_mnt = do_kern_mount(tmpfs_fs_type.name, MS_NOUSER, |
| 2267 | tmpfs_fs_type.name, NULL); |
| 2268 | if (IS_ERR(shm_mnt)) { |
| 2269 | error = PTR_ERR(shm_mnt); |
| 2270 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); |
| 2271 | goto out1; |
| 2272 | } |
| 2273 | return 0; |
| 2274 | |
| 2275 | out1: |
| 2276 | unregister_filesystem(&tmpfs_fs_type); |
| 2277 | out2: |
| 2278 | destroy_inodecache(); |
| 2279 | out3: |
| 2280 | shm_mnt = ERR_PTR(error); |
| 2281 | return error; |
| 2282 | } |
| 2283 | module_init(init_tmpfs) |
| 2284 | |
| 2285 | /* |
| 2286 | * shmem_file_setup - get an unlinked file living in tmpfs |
| 2287 | * |
| 2288 | * @name: name for dentry (to be seen in /proc/<pid>/maps |
| 2289 | * @size: size to be set for the file |
| 2290 | * |
| 2291 | */ |
| 2292 | struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags) |
| 2293 | { |
| 2294 | int error; |
| 2295 | struct file *file; |
| 2296 | struct inode *inode; |
| 2297 | struct dentry *dentry, *root; |
| 2298 | struct qstr this; |
| 2299 | |
| 2300 | if (IS_ERR(shm_mnt)) |
| 2301 | return (void *)shm_mnt; |
| 2302 | |
| 2303 | if (size < 0 || size > SHMEM_MAX_BYTES) |
| 2304 | return ERR_PTR(-EINVAL); |
| 2305 | |
| 2306 | if (shmem_acct_size(flags, size)) |
| 2307 | return ERR_PTR(-ENOMEM); |
| 2308 | |
| 2309 | error = -ENOMEM; |
| 2310 | this.name = name; |
| 2311 | this.len = strlen(name); |
| 2312 | this.hash = 0; /* will go */ |
| 2313 | root = shm_mnt->mnt_root; |
| 2314 | dentry = d_alloc(root, &this); |
| 2315 | if (!dentry) |
| 2316 | goto put_memory; |
| 2317 | |
| 2318 | error = -ENFILE; |
| 2319 | file = get_empty_filp(); |
| 2320 | if (!file) |
| 2321 | goto put_dentry; |
| 2322 | |
| 2323 | error = -ENOSPC; |
| 2324 | inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0); |
| 2325 | if (!inode) |
| 2326 | goto close_file; |
| 2327 | |
| 2328 | SHMEM_I(inode)->flags = flags & VM_ACCOUNT; |
| 2329 | d_instantiate(dentry, inode); |
| 2330 | inode->i_size = size; |
| 2331 | inode->i_nlink = 0; /* It is unlinked */ |
| 2332 | file->f_vfsmnt = mntget(shm_mnt); |
| 2333 | file->f_dentry = dentry; |
| 2334 | file->f_mapping = inode->i_mapping; |
| 2335 | file->f_op = &shmem_file_operations; |
| 2336 | file->f_mode = FMODE_WRITE | FMODE_READ; |
| 2337 | return file; |
| 2338 | |
| 2339 | close_file: |
| 2340 | put_filp(file); |
| 2341 | put_dentry: |
| 2342 | dput(dentry); |
| 2343 | put_memory: |
| 2344 | shmem_unacct_size(flags, size); |
| 2345 | return ERR_PTR(error); |
| 2346 | } |
| 2347 | |
| 2348 | /* |
| 2349 | * shmem_zero_setup - setup a shared anonymous mapping |
| 2350 | * |
| 2351 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff |
| 2352 | */ |
| 2353 | int shmem_zero_setup(struct vm_area_struct *vma) |
| 2354 | { |
| 2355 | struct file *file; |
| 2356 | loff_t size = vma->vm_end - vma->vm_start; |
| 2357 | |
| 2358 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); |
| 2359 | if (IS_ERR(file)) |
| 2360 | return PTR_ERR(file); |
| 2361 | |
| 2362 | if (vma->vm_file) |
| 2363 | fput(vma->vm_file); |
| 2364 | vma->vm_file = file; |
| 2365 | vma->vm_ops = &shmem_vm_ops; |
| 2366 | return 0; |
| 2367 | } |