Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/mm/filemap.c |
| 3 | * |
| 4 | * Copyright (C) 1994-1999 Linus Torvalds |
| 5 | */ |
| 6 | |
| 7 | /* |
| 8 | * This file handles the generic file mmap semantics used by |
| 9 | * most "normal" filesystems (but you don't /have/ to use this: |
| 10 | * the NFS filesystem used to do this differently, for example) |
| 11 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | #include <linux/module.h> |
| 13 | #include <linux/slab.h> |
| 14 | #include <linux/compiler.h> |
| 15 | #include <linux/fs.h> |
Hiro Yoshioka | c22ce14 | 2006-06-23 02:04:16 -0700 | [diff] [blame] | 16 | #include <linux/uaccess.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | #include <linux/aio.h> |
Randy.Dunlap | c59ede7 | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 18 | #include <linux/capability.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | #include <linux/kernel_stat.h> |
| 20 | #include <linux/mm.h> |
| 21 | #include <linux/swap.h> |
| 22 | #include <linux/mman.h> |
| 23 | #include <linux/pagemap.h> |
| 24 | #include <linux/file.h> |
| 25 | #include <linux/uio.h> |
| 26 | #include <linux/hash.h> |
| 27 | #include <linux/writeback.h> |
Linus Torvalds | 5325338 | 2007-10-18 14:47:32 -0700 | [diff] [blame] | 28 | #include <linux/backing-dev.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | #include <linux/pagevec.h> |
| 30 | #include <linux/blkdev.h> |
Emil Medve | 3a424f2 | 2007-10-24 14:18:32 +0200 | [diff] [blame] | 31 | #include <linux/backing-dev.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | #include <linux/security.h> |
| 33 | #include <linux/syscalls.h> |
Paul Jackson | 44110fe | 2006-03-24 03:16:04 -0800 | [diff] [blame] | 34 | #include <linux/cpuset.h> |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 35 | #include <linux/hardirq.h> /* for BUG_ON(!in_atomic()) only */ |
Balbir Singh | 8a9f3cc | 2008-02-07 00:13:53 -0800 | [diff] [blame] | 36 | #include <linux/memcontrol.h> |
Nick Piggin | 0f8053a | 2006-03-22 00:08:33 -0800 | [diff] [blame] | 37 | #include "internal.h" |
| 38 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 39 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 40 | * FIXME: remove all knowledge of the buffer layer from the core VM |
| 41 | */ |
| 42 | #include <linux/buffer_head.h> /* for generic_osync_inode */ |
| 43 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | #include <asm/mman.h> |
| 45 | |
Adrian Bunk | 5ce7852 | 2005-09-10 00:26:28 -0700 | [diff] [blame] | 46 | static ssize_t |
| 47 | generic_file_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, |
| 48 | loff_t offset, unsigned long nr_segs); |
| 49 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | /* |
| 51 | * Shared mappings implemented 30.11.1994. It's not fully working yet, |
| 52 | * though. |
| 53 | * |
| 54 | * Shared mappings now work. 15.8.1995 Bruno. |
| 55 | * |
| 56 | * finished 'unifying' the page and buffer cache and SMP-threaded the |
| 57 | * page-cache, 21.05.1999, Ingo Molnar <mingo@redhat.com> |
| 58 | * |
| 59 | * SMP-threaded pagemap-LRU 1999, Andrea Arcangeli <andrea@suse.de> |
| 60 | */ |
| 61 | |
| 62 | /* |
| 63 | * Lock ordering: |
| 64 | * |
| 65 | * ->i_mmap_lock (vmtruncate) |
| 66 | * ->private_lock (__free_pte->__set_page_dirty_buffers) |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 67 | * ->swap_lock (exclusive_swap_page, others) |
| 68 | * ->mapping->tree_lock |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 69 | * |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 70 | * ->i_mutex |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 71 | * ->i_mmap_lock (truncate->unmap_mapping_range) |
| 72 | * |
| 73 | * ->mmap_sem |
| 74 | * ->i_mmap_lock |
Hugh Dickins | b8072f0 | 2005-10-29 18:16:41 -0700 | [diff] [blame] | 75 | * ->page_table_lock or pte_lock (various, mainly in memory.c) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 76 | * ->mapping->tree_lock (arch-dependent flush_dcache_mmap_lock) |
| 77 | * |
| 78 | * ->mmap_sem |
| 79 | * ->lock_page (access_process_vm) |
| 80 | * |
Nick Piggin | 82591e6 | 2006-10-19 23:29:10 -0700 | [diff] [blame] | 81 | * ->i_mutex (generic_file_buffered_write) |
| 82 | * ->mmap_sem (fault_in_pages_readable->do_page_fault) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 83 | * |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 84 | * ->i_mutex |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 85 | * ->i_alloc_sem (various) |
| 86 | * |
| 87 | * ->inode_lock |
| 88 | * ->sb_lock (fs/fs-writeback.c) |
| 89 | * ->mapping->tree_lock (__sync_single_inode) |
| 90 | * |
| 91 | * ->i_mmap_lock |
| 92 | * ->anon_vma.lock (vma_adjust) |
| 93 | * |
| 94 | * ->anon_vma.lock |
Hugh Dickins | b8072f0 | 2005-10-29 18:16:41 -0700 | [diff] [blame] | 95 | * ->page_table_lock or pte_lock (anon_vma_prepare and various) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 96 | * |
Hugh Dickins | b8072f0 | 2005-10-29 18:16:41 -0700 | [diff] [blame] | 97 | * ->page_table_lock or pte_lock |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 98 | * ->swap_lock (try_to_unmap_one) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | * ->private_lock (try_to_unmap_one) |
| 100 | * ->tree_lock (try_to_unmap_one) |
| 101 | * ->zone.lru_lock (follow_page->mark_page_accessed) |
Nick Piggin | 053837f | 2006-01-18 17:42:27 -0800 | [diff] [blame] | 102 | * ->zone.lru_lock (check_pte_range->isolate_lru_page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | * ->private_lock (page_remove_rmap->set_page_dirty) |
| 104 | * ->tree_lock (page_remove_rmap->set_page_dirty) |
| 105 | * ->inode_lock (page_remove_rmap->set_page_dirty) |
| 106 | * ->inode_lock (zap_pte_range->set_page_dirty) |
| 107 | * ->private_lock (zap_pte_range->__set_page_dirty_buffers) |
| 108 | * |
| 109 | * ->task->proc_lock |
| 110 | * ->dcache_lock (proc_pid_lookup) |
| 111 | */ |
| 112 | |
| 113 | /* |
| 114 | * Remove a page from the page cache and free it. Caller has to make |
| 115 | * sure the page is locked and that nobody else uses it - or that usage |
| 116 | * is safe. The caller must hold a write_lock on the mapping's tree_lock. |
| 117 | */ |
| 118 | void __remove_from_page_cache(struct page *page) |
| 119 | { |
| 120 | struct address_space *mapping = page->mapping; |
| 121 | |
Balbir Singh | 8a9f3cc | 2008-02-07 00:13:53 -0800 | [diff] [blame] | 122 | mem_cgroup_uncharge_page(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 123 | radix_tree_delete(&mapping->page_tree, page->index); |
| 124 | page->mapping = NULL; |
| 125 | mapping->nrpages--; |
Christoph Lameter | 347ce43 | 2006-06-30 01:55:35 -0700 | [diff] [blame] | 126 | __dec_zone_page_state(page, NR_FILE_PAGES); |
Nick Piggin | 4542681 | 2007-07-15 23:38:12 -0700 | [diff] [blame] | 127 | BUG_ON(page_mapped(page)); |
Linus Torvalds | 3a69279 | 2007-12-19 14:05:13 -0800 | [diff] [blame] | 128 | |
| 129 | /* |
| 130 | * Some filesystems seem to re-dirty the page even after |
| 131 | * the VM has canceled the dirty bit (eg ext3 journaling). |
| 132 | * |
| 133 | * Fix it up by doing a final dirty accounting check after |
| 134 | * having removed the page entirely. |
| 135 | */ |
| 136 | if (PageDirty(page) && mapping_cap_account_dirty(mapping)) { |
| 137 | dec_zone_page_state(page, NR_FILE_DIRTY); |
| 138 | dec_bdi_stat(mapping->backing_dev_info, BDI_RECLAIMABLE); |
| 139 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 140 | } |
| 141 | |
| 142 | void remove_from_page_cache(struct page *page) |
| 143 | { |
| 144 | struct address_space *mapping = page->mapping; |
| 145 | |
Matt Mackall | cd7619d | 2005-05-01 08:59:01 -0700 | [diff] [blame] | 146 | BUG_ON(!PageLocked(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 147 | |
| 148 | write_lock_irq(&mapping->tree_lock); |
| 149 | __remove_from_page_cache(page); |
| 150 | write_unlock_irq(&mapping->tree_lock); |
| 151 | } |
| 152 | |
| 153 | static int sync_page(void *word) |
| 154 | { |
| 155 | struct address_space *mapping; |
| 156 | struct page *page; |
| 157 | |
Andi Kleen | 07808b7 | 2005-11-05 17:25:53 +0100 | [diff] [blame] | 158 | page = container_of((unsigned long *)word, struct page, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 159 | |
| 160 | /* |
William Lee Irwin III | dd1d5af | 2005-05-01 08:58:38 -0700 | [diff] [blame] | 161 | * page_mapping() is being called without PG_locked held. |
| 162 | * Some knowledge of the state and use of the page is used to |
| 163 | * reduce the requirements down to a memory barrier. |
| 164 | * The danger here is of a stale page_mapping() return value |
| 165 | * indicating a struct address_space different from the one it's |
| 166 | * associated with when it is associated with one. |
| 167 | * After smp_mb(), it's either the correct page_mapping() for |
| 168 | * the page, or an old page_mapping() and the page's own |
| 169 | * page_mapping() has gone NULL. |
| 170 | * The ->sync_page() address_space operation must tolerate |
| 171 | * page_mapping() going NULL. By an amazing coincidence, |
| 172 | * this comes about because none of the users of the page |
| 173 | * in the ->sync_page() methods make essential use of the |
| 174 | * page_mapping(), merely passing the page down to the backing |
| 175 | * device's unplug functions when it's non-NULL, which in turn |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 176 | * ignore it for all cases but swap, where only page_private(page) is |
William Lee Irwin III | dd1d5af | 2005-05-01 08:58:38 -0700 | [diff] [blame] | 177 | * of interest. When page_mapping() does go NULL, the entire |
| 178 | * call stack gracefully ignores the page and returns. |
| 179 | * -- wli |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 180 | */ |
| 181 | smp_mb(); |
| 182 | mapping = page_mapping(page); |
| 183 | if (mapping && mapping->a_ops && mapping->a_ops->sync_page) |
| 184 | mapping->a_ops->sync_page(page); |
| 185 | io_schedule(); |
| 186 | return 0; |
| 187 | } |
| 188 | |
Matthew Wilcox | 2687a35 | 2007-12-06 11:18:49 -0500 | [diff] [blame] | 189 | static int sync_page_killable(void *word) |
| 190 | { |
| 191 | sync_page(word); |
| 192 | return fatal_signal_pending(current) ? -EINTR : 0; |
| 193 | } |
| 194 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 195 | /** |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 196 | * __filemap_fdatawrite_range - start writeback on mapping dirty pages in range |
Martin Waitz | 67be2dd | 2005-05-01 08:59:26 -0700 | [diff] [blame] | 197 | * @mapping: address space structure to write |
| 198 | * @start: offset in bytes where the range starts |
Andrew Morton | 469eb4d | 2006-03-24 03:17:45 -0800 | [diff] [blame] | 199 | * @end: offset in bytes where the range ends (inclusive) |
Martin Waitz | 67be2dd | 2005-05-01 08:59:26 -0700 | [diff] [blame] | 200 | * @sync_mode: enable synchronous operation |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 201 | * |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 202 | * Start writeback against all of a mapping's dirty pages that lie |
| 203 | * within the byte offsets <start, end> inclusive. |
| 204 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 205 | * If sync_mode is WB_SYNC_ALL then this is a "data integrity" operation, as |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 206 | * opposed to a regular memory cleansing writeback. The difference between |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 207 | * these two operations is that if a dirty page/buffer is encountered, it must |
| 208 | * be waited upon, and not just skipped over. |
| 209 | */ |
Andrew Morton | ebcf28e | 2006-03-24 03:18:04 -0800 | [diff] [blame] | 210 | int __filemap_fdatawrite_range(struct address_space *mapping, loff_t start, |
| 211 | loff_t end, int sync_mode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 212 | { |
| 213 | int ret; |
| 214 | struct writeback_control wbc = { |
| 215 | .sync_mode = sync_mode, |
| 216 | .nr_to_write = mapping->nrpages * 2, |
OGAWA Hirofumi | 111ebb6 | 2006-06-23 02:03:26 -0700 | [diff] [blame] | 217 | .range_start = start, |
| 218 | .range_end = end, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 219 | }; |
| 220 | |
| 221 | if (!mapping_cap_writeback_dirty(mapping)) |
| 222 | return 0; |
| 223 | |
| 224 | ret = do_writepages(mapping, &wbc); |
| 225 | return ret; |
| 226 | } |
| 227 | |
| 228 | static inline int __filemap_fdatawrite(struct address_space *mapping, |
| 229 | int sync_mode) |
| 230 | { |
OGAWA Hirofumi | 111ebb6 | 2006-06-23 02:03:26 -0700 | [diff] [blame] | 231 | return __filemap_fdatawrite_range(mapping, 0, LLONG_MAX, sync_mode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 232 | } |
| 233 | |
| 234 | int filemap_fdatawrite(struct address_space *mapping) |
| 235 | { |
| 236 | return __filemap_fdatawrite(mapping, WB_SYNC_ALL); |
| 237 | } |
| 238 | EXPORT_SYMBOL(filemap_fdatawrite); |
| 239 | |
Andrew Morton | ebcf28e | 2006-03-24 03:18:04 -0800 | [diff] [blame] | 240 | static int filemap_fdatawrite_range(struct address_space *mapping, loff_t start, |
| 241 | loff_t end) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 242 | { |
| 243 | return __filemap_fdatawrite_range(mapping, start, end, WB_SYNC_ALL); |
| 244 | } |
| 245 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 246 | /** |
| 247 | * filemap_flush - mostly a non-blocking flush |
| 248 | * @mapping: target address_space |
| 249 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 250 | * This is a mostly non-blocking flush. Not suitable for data-integrity |
| 251 | * purposes - I/O may not be started against all dirty pages. |
| 252 | */ |
| 253 | int filemap_flush(struct address_space *mapping) |
| 254 | { |
| 255 | return __filemap_fdatawrite(mapping, WB_SYNC_NONE); |
| 256 | } |
| 257 | EXPORT_SYMBOL(filemap_flush); |
| 258 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 259 | /** |
| 260 | * wait_on_page_writeback_range - wait for writeback to complete |
| 261 | * @mapping: target address_space |
| 262 | * @start: beginning page index |
| 263 | * @end: ending page index |
| 264 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 265 | * Wait for writeback to complete against pages indexed by start->end |
| 266 | * inclusive |
| 267 | */ |
Andrew Morton | ebcf28e | 2006-03-24 03:18:04 -0800 | [diff] [blame] | 268 | int wait_on_page_writeback_range(struct address_space *mapping, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 269 | pgoff_t start, pgoff_t end) |
| 270 | { |
| 271 | struct pagevec pvec; |
| 272 | int nr_pages; |
| 273 | int ret = 0; |
| 274 | pgoff_t index; |
| 275 | |
| 276 | if (end < start) |
| 277 | return 0; |
| 278 | |
| 279 | pagevec_init(&pvec, 0); |
| 280 | index = start; |
| 281 | while ((index <= end) && |
| 282 | (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, |
| 283 | PAGECACHE_TAG_WRITEBACK, |
| 284 | min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1)) != 0) { |
| 285 | unsigned i; |
| 286 | |
| 287 | for (i = 0; i < nr_pages; i++) { |
| 288 | struct page *page = pvec.pages[i]; |
| 289 | |
| 290 | /* until radix tree lookup accepts end_index */ |
| 291 | if (page->index > end) |
| 292 | continue; |
| 293 | |
| 294 | wait_on_page_writeback(page); |
| 295 | if (PageError(page)) |
| 296 | ret = -EIO; |
| 297 | } |
| 298 | pagevec_release(&pvec); |
| 299 | cond_resched(); |
| 300 | } |
| 301 | |
| 302 | /* Check for outstanding write errors */ |
| 303 | if (test_and_clear_bit(AS_ENOSPC, &mapping->flags)) |
| 304 | ret = -ENOSPC; |
| 305 | if (test_and_clear_bit(AS_EIO, &mapping->flags)) |
| 306 | ret = -EIO; |
| 307 | |
| 308 | return ret; |
| 309 | } |
| 310 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 311 | /** |
| 312 | * sync_page_range - write and wait on all pages in the passed range |
| 313 | * @inode: target inode |
| 314 | * @mapping: target address_space |
| 315 | * @pos: beginning offset in pages to write |
| 316 | * @count: number of bytes to write |
| 317 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 318 | * Write and wait upon all the pages in the passed range. This is a "data |
| 319 | * integrity" operation. It waits upon in-flight writeout before starting and |
| 320 | * waiting upon new writeout. If there was an IO error, return it. |
| 321 | * |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 322 | * We need to re-take i_mutex during the generic_osync_inode list walk because |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 323 | * it is otherwise livelockable. |
| 324 | */ |
| 325 | int sync_page_range(struct inode *inode, struct address_space *mapping, |
OGAWA Hirofumi | 268fc16 | 2006-01-08 01:02:12 -0800 | [diff] [blame] | 326 | loff_t pos, loff_t count) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 327 | { |
| 328 | pgoff_t start = pos >> PAGE_CACHE_SHIFT; |
| 329 | pgoff_t end = (pos + count - 1) >> PAGE_CACHE_SHIFT; |
| 330 | int ret; |
| 331 | |
| 332 | if (!mapping_cap_writeback_dirty(mapping) || !count) |
| 333 | return 0; |
| 334 | ret = filemap_fdatawrite_range(mapping, pos, pos + count - 1); |
| 335 | if (ret == 0) { |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 336 | mutex_lock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 337 | ret = generic_osync_inode(inode, mapping, OSYNC_METADATA); |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 338 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 339 | } |
| 340 | if (ret == 0) |
| 341 | ret = wait_on_page_writeback_range(mapping, start, end); |
| 342 | return ret; |
| 343 | } |
| 344 | EXPORT_SYMBOL(sync_page_range); |
| 345 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 346 | /** |
| 347 | * sync_page_range_nolock |
| 348 | * @inode: target inode |
| 349 | * @mapping: target address_space |
| 350 | * @pos: beginning offset in pages to write |
| 351 | * @count: number of bytes to write |
| 352 | * |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame] | 353 | * Note: Holding i_mutex across sync_page_range_nolock() is not a good idea |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 354 | * as it forces O_SYNC writers to different parts of the same file |
| 355 | * to be serialised right until io completion. |
| 356 | */ |
OGAWA Hirofumi | 268fc16 | 2006-01-08 01:02:12 -0800 | [diff] [blame] | 357 | int sync_page_range_nolock(struct inode *inode, struct address_space *mapping, |
| 358 | loff_t pos, loff_t count) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 359 | { |
| 360 | pgoff_t start = pos >> PAGE_CACHE_SHIFT; |
| 361 | pgoff_t end = (pos + count - 1) >> PAGE_CACHE_SHIFT; |
| 362 | int ret; |
| 363 | |
| 364 | if (!mapping_cap_writeback_dirty(mapping) || !count) |
| 365 | return 0; |
| 366 | ret = filemap_fdatawrite_range(mapping, pos, pos + count - 1); |
| 367 | if (ret == 0) |
| 368 | ret = generic_osync_inode(inode, mapping, OSYNC_METADATA); |
| 369 | if (ret == 0) |
| 370 | ret = wait_on_page_writeback_range(mapping, start, end); |
| 371 | return ret; |
| 372 | } |
OGAWA Hirofumi | 268fc16 | 2006-01-08 01:02:12 -0800 | [diff] [blame] | 373 | EXPORT_SYMBOL(sync_page_range_nolock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 374 | |
| 375 | /** |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 376 | * filemap_fdatawait - wait for all under-writeback pages to complete |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 377 | * @mapping: address space structure to wait for |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 378 | * |
| 379 | * Walk the list of under-writeback pages of the given address space |
| 380 | * and wait for all of them. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 381 | */ |
| 382 | int filemap_fdatawait(struct address_space *mapping) |
| 383 | { |
| 384 | loff_t i_size = i_size_read(mapping->host); |
| 385 | |
| 386 | if (i_size == 0) |
| 387 | return 0; |
| 388 | |
| 389 | return wait_on_page_writeback_range(mapping, 0, |
| 390 | (i_size - 1) >> PAGE_CACHE_SHIFT); |
| 391 | } |
| 392 | EXPORT_SYMBOL(filemap_fdatawait); |
| 393 | |
| 394 | int filemap_write_and_wait(struct address_space *mapping) |
| 395 | { |
OGAWA Hirofumi | 28fd129 | 2006-01-08 01:02:14 -0800 | [diff] [blame] | 396 | int err = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 397 | |
| 398 | if (mapping->nrpages) { |
OGAWA Hirofumi | 28fd129 | 2006-01-08 01:02:14 -0800 | [diff] [blame] | 399 | err = filemap_fdatawrite(mapping); |
| 400 | /* |
| 401 | * Even if the above returned error, the pages may be |
| 402 | * written partially (e.g. -ENOSPC), so we wait for it. |
| 403 | * But the -EIO is special case, it may indicate the worst |
| 404 | * thing (e.g. bug) happened, so we avoid waiting for it. |
| 405 | */ |
| 406 | if (err != -EIO) { |
| 407 | int err2 = filemap_fdatawait(mapping); |
| 408 | if (!err) |
| 409 | err = err2; |
| 410 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 411 | } |
OGAWA Hirofumi | 28fd129 | 2006-01-08 01:02:14 -0800 | [diff] [blame] | 412 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 413 | } |
OGAWA Hirofumi | 28fd129 | 2006-01-08 01:02:14 -0800 | [diff] [blame] | 414 | EXPORT_SYMBOL(filemap_write_and_wait); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 415 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 416 | /** |
| 417 | * filemap_write_and_wait_range - write out & wait on a file range |
| 418 | * @mapping: the address_space for the pages |
| 419 | * @lstart: offset in bytes where the range starts |
| 420 | * @lend: offset in bytes where the range ends (inclusive) |
| 421 | * |
Andrew Morton | 469eb4d | 2006-03-24 03:17:45 -0800 | [diff] [blame] | 422 | * Write out and wait upon file offsets lstart->lend, inclusive. |
| 423 | * |
| 424 | * Note that `lend' is inclusive (describes the last byte to be written) so |
| 425 | * that this function can be used to write to the very end-of-file (end = -1). |
| 426 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 427 | int filemap_write_and_wait_range(struct address_space *mapping, |
| 428 | loff_t lstart, loff_t lend) |
| 429 | { |
OGAWA Hirofumi | 28fd129 | 2006-01-08 01:02:14 -0800 | [diff] [blame] | 430 | int err = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 431 | |
| 432 | if (mapping->nrpages) { |
OGAWA Hirofumi | 28fd129 | 2006-01-08 01:02:14 -0800 | [diff] [blame] | 433 | err = __filemap_fdatawrite_range(mapping, lstart, lend, |
| 434 | WB_SYNC_ALL); |
| 435 | /* See comment of filemap_write_and_wait() */ |
| 436 | if (err != -EIO) { |
| 437 | int err2 = wait_on_page_writeback_range(mapping, |
| 438 | lstart >> PAGE_CACHE_SHIFT, |
| 439 | lend >> PAGE_CACHE_SHIFT); |
| 440 | if (!err) |
| 441 | err = err2; |
| 442 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 443 | } |
OGAWA Hirofumi | 28fd129 | 2006-01-08 01:02:14 -0800 | [diff] [blame] | 444 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 445 | } |
| 446 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 447 | /** |
| 448 | * add_to_page_cache - add newly allocated pagecache pages |
| 449 | * @page: page to add |
| 450 | * @mapping: the page's address_space |
| 451 | * @offset: page index |
| 452 | * @gfp_mask: page allocation mode |
| 453 | * |
| 454 | * This function is used to add newly allocated pagecache pages; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 455 | * the page is new, so we can just run SetPageLocked() against it. |
| 456 | * The other page state flags were set by rmqueue(). |
| 457 | * |
| 458 | * This function does not add the page to the LRU. The caller must do that. |
| 459 | */ |
| 460 | int add_to_page_cache(struct page *page, struct address_space *mapping, |
Al Viro | 6daa0e2 | 2005-10-21 03:18:50 -0400 | [diff] [blame] | 461 | pgoff_t offset, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 462 | { |
Badari Pulavarty | 4c6bc8d | 2008-02-07 00:14:05 -0800 | [diff] [blame] | 463 | int error = mem_cgroup_cache_charge(page, current->mm, |
| 464 | gfp_mask & ~__GFP_HIGHMEM); |
Balbir Singh | 35c754d | 2008-02-07 00:14:05 -0800 | [diff] [blame] | 465 | if (error) |
| 466 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 467 | |
Balbir Singh | 35c754d | 2008-02-07 00:14:05 -0800 | [diff] [blame] | 468 | error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 469 | if (error == 0) { |
| 470 | write_lock_irq(&mapping->tree_lock); |
| 471 | error = radix_tree_insert(&mapping->page_tree, offset, page); |
| 472 | if (!error) { |
| 473 | page_cache_get(page); |
| 474 | SetPageLocked(page); |
| 475 | page->mapping = mapping; |
| 476 | page->index = offset; |
| 477 | mapping->nrpages++; |
Christoph Lameter | 347ce43 | 2006-06-30 01:55:35 -0700 | [diff] [blame] | 478 | __inc_zone_page_state(page, NR_FILE_PAGES); |
Balbir Singh | 8a9f3cc | 2008-02-07 00:13:53 -0800 | [diff] [blame] | 479 | } else |
| 480 | mem_cgroup_uncharge_page(page); |
| 481 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 482 | write_unlock_irq(&mapping->tree_lock); |
| 483 | radix_tree_preload_end(); |
Balbir Singh | 35c754d | 2008-02-07 00:14:05 -0800 | [diff] [blame] | 484 | } else |
| 485 | mem_cgroup_uncharge_page(page); |
Balbir Singh | 8a9f3cc | 2008-02-07 00:13:53 -0800 | [diff] [blame] | 486 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 487 | return error; |
| 488 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 489 | EXPORT_SYMBOL(add_to_page_cache); |
| 490 | |
| 491 | int add_to_page_cache_lru(struct page *page, struct address_space *mapping, |
Al Viro | 6daa0e2 | 2005-10-21 03:18:50 -0400 | [diff] [blame] | 492 | pgoff_t offset, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 493 | { |
| 494 | int ret = add_to_page_cache(page, mapping, offset, gfp_mask); |
| 495 | if (ret == 0) |
| 496 | lru_cache_add(page); |
| 497 | return ret; |
| 498 | } |
| 499 | |
Paul Jackson | 44110fe | 2006-03-24 03:16:04 -0800 | [diff] [blame] | 500 | #ifdef CONFIG_NUMA |
Nick Piggin | 2ae8814 | 2006-10-28 10:38:23 -0700 | [diff] [blame] | 501 | struct page *__page_cache_alloc(gfp_t gfp) |
Paul Jackson | 44110fe | 2006-03-24 03:16:04 -0800 | [diff] [blame] | 502 | { |
| 503 | if (cpuset_do_page_mem_spread()) { |
| 504 | int n = cpuset_mem_spread_node(); |
Nick Piggin | 2ae8814 | 2006-10-28 10:38:23 -0700 | [diff] [blame] | 505 | return alloc_pages_node(n, gfp, 0); |
Paul Jackson | 44110fe | 2006-03-24 03:16:04 -0800 | [diff] [blame] | 506 | } |
Nick Piggin | 2ae8814 | 2006-10-28 10:38:23 -0700 | [diff] [blame] | 507 | return alloc_pages(gfp, 0); |
Paul Jackson | 44110fe | 2006-03-24 03:16:04 -0800 | [diff] [blame] | 508 | } |
Nick Piggin | 2ae8814 | 2006-10-28 10:38:23 -0700 | [diff] [blame] | 509 | EXPORT_SYMBOL(__page_cache_alloc); |
Paul Jackson | 44110fe | 2006-03-24 03:16:04 -0800 | [diff] [blame] | 510 | #endif |
| 511 | |
Nick Piggin | db37648 | 2006-09-25 23:31:24 -0700 | [diff] [blame] | 512 | static int __sleep_on_page_lock(void *word) |
| 513 | { |
| 514 | io_schedule(); |
| 515 | return 0; |
| 516 | } |
| 517 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 518 | /* |
| 519 | * In order to wait for pages to become available there must be |
| 520 | * waitqueues associated with pages. By using a hash table of |
| 521 | * waitqueues where the bucket discipline is to maintain all |
| 522 | * waiters on the same queue and wake all when any of the pages |
| 523 | * become available, and for the woken contexts to check to be |
| 524 | * sure the appropriate page became available, this saves space |
| 525 | * at a cost of "thundering herd" phenomena during rare hash |
| 526 | * collisions. |
| 527 | */ |
| 528 | static wait_queue_head_t *page_waitqueue(struct page *page) |
| 529 | { |
| 530 | const struct zone *zone = page_zone(page); |
| 531 | |
| 532 | return &zone->wait_table[hash_ptr(page, zone->wait_table_bits)]; |
| 533 | } |
| 534 | |
| 535 | static inline void wake_up_page(struct page *page, int bit) |
| 536 | { |
| 537 | __wake_up_bit(page_waitqueue(page), &page->flags, bit); |
| 538 | } |
| 539 | |
Harvey Harrison | 920c7a5 | 2008-02-04 22:29:26 -0800 | [diff] [blame] | 540 | void wait_on_page_bit(struct page *page, int bit_nr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 541 | { |
| 542 | DEFINE_WAIT_BIT(wait, &page->flags, bit_nr); |
| 543 | |
| 544 | if (test_bit(bit_nr, &page->flags)) |
| 545 | __wait_on_bit(page_waitqueue(page), &wait, sync_page, |
| 546 | TASK_UNINTERRUPTIBLE); |
| 547 | } |
| 548 | EXPORT_SYMBOL(wait_on_page_bit); |
| 549 | |
| 550 | /** |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 551 | * unlock_page - unlock a locked page |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 552 | * @page: the page |
| 553 | * |
| 554 | * Unlocks the page and wakes up sleepers in ___wait_on_page_locked(). |
| 555 | * Also wakes sleepers in wait_on_page_writeback() because the wakeup |
| 556 | * mechananism between PageLocked pages and PageWriteback pages is shared. |
| 557 | * But that's OK - sleepers in wait_on_page_writeback() just go back to sleep. |
| 558 | * |
| 559 | * The first mb is necessary to safely close the critical section opened by the |
| 560 | * TestSetPageLocked(), the second mb is necessary to enforce ordering between |
| 561 | * the clear_bit and the read of the waitqueue (to avoid SMP races with a |
| 562 | * parallel wait_on_page_locked()). |
| 563 | */ |
Harvey Harrison | 920c7a5 | 2008-02-04 22:29:26 -0800 | [diff] [blame] | 564 | void unlock_page(struct page *page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 565 | { |
| 566 | smp_mb__before_clear_bit(); |
| 567 | if (!TestClearPageLocked(page)) |
| 568 | BUG(); |
| 569 | smp_mb__after_clear_bit(); |
| 570 | wake_up_page(page, PG_locked); |
| 571 | } |
| 572 | EXPORT_SYMBOL(unlock_page); |
| 573 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 574 | /** |
| 575 | * end_page_writeback - end writeback against a page |
| 576 | * @page: the page |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 577 | */ |
| 578 | void end_page_writeback(struct page *page) |
| 579 | { |
| 580 | if (!TestClearPageReclaim(page) || rotate_reclaimable_page(page)) { |
| 581 | if (!test_clear_page_writeback(page)) |
| 582 | BUG(); |
| 583 | } |
| 584 | smp_mb__after_clear_bit(); |
| 585 | wake_up_page(page, PG_writeback); |
| 586 | } |
| 587 | EXPORT_SYMBOL(end_page_writeback); |
| 588 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 589 | /** |
| 590 | * __lock_page - get a lock on the page, assuming we need to sleep to get it |
| 591 | * @page: the page to lock |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 592 | * |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 593 | * Ugly. Running sync_page() in state TASK_UNINTERRUPTIBLE is scary. If some |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 594 | * random driver's requestfn sets TASK_RUNNING, we could busywait. However |
| 595 | * chances are that on the second loop, the block layer's plug list is empty, |
| 596 | * so sync_page() will then return in state TASK_UNINTERRUPTIBLE. |
| 597 | */ |
Harvey Harrison | 920c7a5 | 2008-02-04 22:29:26 -0800 | [diff] [blame] | 598 | void __lock_page(struct page *page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 599 | { |
| 600 | DEFINE_WAIT_BIT(wait, &page->flags, PG_locked); |
| 601 | |
| 602 | __wait_on_bit_lock(page_waitqueue(page), &wait, sync_page, |
| 603 | TASK_UNINTERRUPTIBLE); |
| 604 | } |
| 605 | EXPORT_SYMBOL(__lock_page); |
| 606 | |
Harvey Harrison | b5606c2 | 2008-02-13 15:03:16 -0800 | [diff] [blame^] | 607 | int __lock_page_killable(struct page *page) |
Matthew Wilcox | 2687a35 | 2007-12-06 11:18:49 -0500 | [diff] [blame] | 608 | { |
| 609 | DEFINE_WAIT_BIT(wait, &page->flags, PG_locked); |
| 610 | |
| 611 | return __wait_on_bit_lock(page_waitqueue(page), &wait, |
| 612 | sync_page_killable, TASK_KILLABLE); |
| 613 | } |
| 614 | |
Nick Piggin | db37648 | 2006-09-25 23:31:24 -0700 | [diff] [blame] | 615 | /* |
| 616 | * Variant of lock_page that does not require the caller to hold a reference |
| 617 | * on the page's mapping. |
| 618 | */ |
Harvey Harrison | 920c7a5 | 2008-02-04 22:29:26 -0800 | [diff] [blame] | 619 | void __lock_page_nosync(struct page *page) |
Nick Piggin | db37648 | 2006-09-25 23:31:24 -0700 | [diff] [blame] | 620 | { |
| 621 | DEFINE_WAIT_BIT(wait, &page->flags, PG_locked); |
| 622 | __wait_on_bit_lock(page_waitqueue(page), &wait, __sleep_on_page_lock, |
| 623 | TASK_UNINTERRUPTIBLE); |
| 624 | } |
| 625 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 626 | /** |
| 627 | * find_get_page - find and get a page reference |
| 628 | * @mapping: the address_space to search |
| 629 | * @offset: the page index |
| 630 | * |
Nick Piggin | da6052f | 2006-09-25 23:31:35 -0700 | [diff] [blame] | 631 | * Is there a pagecache struct page at the given (mapping, offset) tuple? |
| 632 | * If yes, increment its refcount and return it; if no, return NULL. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 633 | */ |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 634 | struct page * find_get_page(struct address_space *mapping, pgoff_t offset) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 635 | { |
| 636 | struct page *page; |
| 637 | |
| 638 | read_lock_irq(&mapping->tree_lock); |
| 639 | page = radix_tree_lookup(&mapping->page_tree, offset); |
| 640 | if (page) |
| 641 | page_cache_get(page); |
| 642 | read_unlock_irq(&mapping->tree_lock); |
| 643 | return page; |
| 644 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 645 | EXPORT_SYMBOL(find_get_page); |
| 646 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 647 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 648 | * find_lock_page - locate, pin and lock a pagecache page |
Martin Waitz | 67be2dd | 2005-05-01 08:59:26 -0700 | [diff] [blame] | 649 | * @mapping: the address_space to search |
| 650 | * @offset: the page index |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 651 | * |
| 652 | * Locates the desired pagecache page, locks it, increments its reference |
| 653 | * count and returns its address. |
| 654 | * |
| 655 | * Returns zero if the page was not present. find_lock_page() may sleep. |
| 656 | */ |
| 657 | struct page *find_lock_page(struct address_space *mapping, |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 658 | pgoff_t offset) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 659 | { |
| 660 | struct page *page; |
| 661 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 662 | repeat: |
Nick Piggin | 45726cb | 2007-10-16 01:24:41 -0700 | [diff] [blame] | 663 | read_lock_irq(&mapping->tree_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 664 | page = radix_tree_lookup(&mapping->page_tree, offset); |
| 665 | if (page) { |
| 666 | page_cache_get(page); |
| 667 | if (TestSetPageLocked(page)) { |
| 668 | read_unlock_irq(&mapping->tree_lock); |
Nikita Danilov | bbfbb7c | 2006-01-06 00:11:08 -0800 | [diff] [blame] | 669 | __lock_page(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 670 | |
| 671 | /* Has the page been truncated while we slept? */ |
Nick Piggin | 45726cb | 2007-10-16 01:24:41 -0700 | [diff] [blame] | 672 | if (unlikely(page->mapping != mapping)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 673 | unlock_page(page); |
| 674 | page_cache_release(page); |
| 675 | goto repeat; |
| 676 | } |
Nick Piggin | 45726cb | 2007-10-16 01:24:41 -0700 | [diff] [blame] | 677 | VM_BUG_ON(page->index != offset); |
| 678 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 679 | } |
| 680 | } |
| 681 | read_unlock_irq(&mapping->tree_lock); |
Nick Piggin | 45726cb | 2007-10-16 01:24:41 -0700 | [diff] [blame] | 682 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 683 | return page; |
| 684 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 685 | EXPORT_SYMBOL(find_lock_page); |
| 686 | |
| 687 | /** |
| 688 | * find_or_create_page - locate or add a pagecache page |
Martin Waitz | 67be2dd | 2005-05-01 08:59:26 -0700 | [diff] [blame] | 689 | * @mapping: the page's address_space |
| 690 | * @index: the page's index into the mapping |
| 691 | * @gfp_mask: page allocation mode |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 692 | * |
| 693 | * Locates a page in the pagecache. If the page is not present, a new page |
| 694 | * is allocated using @gfp_mask and is added to the pagecache and to the VM's |
| 695 | * LRU list. The returned page is locked and has its reference count |
| 696 | * incremented. |
| 697 | * |
| 698 | * find_or_create_page() may sleep, even if @gfp_flags specifies an atomic |
| 699 | * allocation! |
| 700 | * |
| 701 | * find_or_create_page() returns the desired page's address, or zero on |
| 702 | * memory exhaustion. |
| 703 | */ |
| 704 | struct page *find_or_create_page(struct address_space *mapping, |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 705 | pgoff_t index, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 706 | { |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 707 | struct page *page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 708 | int err; |
| 709 | repeat: |
| 710 | page = find_lock_page(mapping, index); |
| 711 | if (!page) { |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 712 | page = __page_cache_alloc(gfp_mask); |
| 713 | if (!page) |
| 714 | return NULL; |
| 715 | err = add_to_page_cache_lru(page, mapping, index, gfp_mask); |
| 716 | if (unlikely(err)) { |
| 717 | page_cache_release(page); |
| 718 | page = NULL; |
| 719 | if (err == -EEXIST) |
| 720 | goto repeat; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 721 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 722 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 723 | return page; |
| 724 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 725 | EXPORT_SYMBOL(find_or_create_page); |
| 726 | |
| 727 | /** |
| 728 | * find_get_pages - gang pagecache lookup |
| 729 | * @mapping: The address_space to search |
| 730 | * @start: The starting page index |
| 731 | * @nr_pages: The maximum number of pages |
| 732 | * @pages: Where the resulting pages are placed |
| 733 | * |
| 734 | * find_get_pages() will search for and return a group of up to |
| 735 | * @nr_pages pages in the mapping. The pages are placed at @pages. |
| 736 | * find_get_pages() takes a reference against the returned pages. |
| 737 | * |
| 738 | * The search returns a group of mapping-contiguous pages with ascending |
| 739 | * indexes. There may be holes in the indices due to not-present pages. |
| 740 | * |
| 741 | * find_get_pages() returns the number of pages which were found. |
| 742 | */ |
| 743 | unsigned find_get_pages(struct address_space *mapping, pgoff_t start, |
| 744 | unsigned int nr_pages, struct page **pages) |
| 745 | { |
| 746 | unsigned int i; |
| 747 | unsigned int ret; |
| 748 | |
| 749 | read_lock_irq(&mapping->tree_lock); |
| 750 | ret = radix_tree_gang_lookup(&mapping->page_tree, |
| 751 | (void **)pages, start, nr_pages); |
| 752 | for (i = 0; i < ret; i++) |
| 753 | page_cache_get(pages[i]); |
| 754 | read_unlock_irq(&mapping->tree_lock); |
| 755 | return ret; |
| 756 | } |
| 757 | |
Jens Axboe | ebf4350 | 2006-04-27 08:46:01 +0200 | [diff] [blame] | 758 | /** |
| 759 | * find_get_pages_contig - gang contiguous pagecache lookup |
| 760 | * @mapping: The address_space to search |
| 761 | * @index: The starting page index |
| 762 | * @nr_pages: The maximum number of pages |
| 763 | * @pages: Where the resulting pages are placed |
| 764 | * |
| 765 | * find_get_pages_contig() works exactly like find_get_pages(), except |
| 766 | * that the returned number of pages are guaranteed to be contiguous. |
| 767 | * |
| 768 | * find_get_pages_contig() returns the number of pages which were found. |
| 769 | */ |
| 770 | unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index, |
| 771 | unsigned int nr_pages, struct page **pages) |
| 772 | { |
| 773 | unsigned int i; |
| 774 | unsigned int ret; |
| 775 | |
| 776 | read_lock_irq(&mapping->tree_lock); |
| 777 | ret = radix_tree_gang_lookup(&mapping->page_tree, |
| 778 | (void **)pages, index, nr_pages); |
| 779 | for (i = 0; i < ret; i++) { |
| 780 | if (pages[i]->mapping == NULL || pages[i]->index != index) |
| 781 | break; |
| 782 | |
| 783 | page_cache_get(pages[i]); |
| 784 | index++; |
| 785 | } |
| 786 | read_unlock_irq(&mapping->tree_lock); |
| 787 | return i; |
| 788 | } |
David Howells | ef71c15 | 2007-05-09 02:33:44 -0700 | [diff] [blame] | 789 | EXPORT_SYMBOL(find_get_pages_contig); |
Jens Axboe | ebf4350 | 2006-04-27 08:46:01 +0200 | [diff] [blame] | 790 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 791 | /** |
| 792 | * find_get_pages_tag - find and return pages that match @tag |
| 793 | * @mapping: the address_space to search |
| 794 | * @index: the starting page index |
| 795 | * @tag: the tag index |
| 796 | * @nr_pages: the maximum number of pages |
| 797 | * @pages: where the resulting pages are placed |
| 798 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 799 | * Like find_get_pages, except we only return pages which are tagged with |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 800 | * @tag. We update @index to index the next page for the traversal. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 801 | */ |
| 802 | unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index, |
| 803 | int tag, unsigned int nr_pages, struct page **pages) |
| 804 | { |
| 805 | unsigned int i; |
| 806 | unsigned int ret; |
| 807 | |
| 808 | read_lock_irq(&mapping->tree_lock); |
| 809 | ret = radix_tree_gang_lookup_tag(&mapping->page_tree, |
| 810 | (void **)pages, *index, nr_pages, tag); |
| 811 | for (i = 0; i < ret; i++) |
| 812 | page_cache_get(pages[i]); |
| 813 | if (ret) |
| 814 | *index = pages[ret - 1]->index + 1; |
| 815 | read_unlock_irq(&mapping->tree_lock); |
| 816 | return ret; |
| 817 | } |
David Howells | ef71c15 | 2007-05-09 02:33:44 -0700 | [diff] [blame] | 818 | EXPORT_SYMBOL(find_get_pages_tag); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 819 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 820 | /** |
| 821 | * grab_cache_page_nowait - returns locked page at given index in given cache |
| 822 | * @mapping: target address_space |
| 823 | * @index: the page index |
| 824 | * |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame] | 825 | * Same as grab_cache_page(), but do not wait if the page is unavailable. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 826 | * This is intended for speculative data generators, where the data can |
| 827 | * be regenerated if the page couldn't be grabbed. This routine should |
| 828 | * be safe to call while holding the lock for another page. |
| 829 | * |
| 830 | * Clear __GFP_FS when allocating the page to avoid recursion into the fs |
| 831 | * and deadlock against the caller's locked page. |
| 832 | */ |
| 833 | struct page * |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 834 | grab_cache_page_nowait(struct address_space *mapping, pgoff_t index) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 835 | { |
| 836 | struct page *page = find_get_page(mapping, index); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 837 | |
| 838 | if (page) { |
| 839 | if (!TestSetPageLocked(page)) |
| 840 | return page; |
| 841 | page_cache_release(page); |
| 842 | return NULL; |
| 843 | } |
Nick Piggin | 2ae8814 | 2006-10-28 10:38:23 -0700 | [diff] [blame] | 844 | page = __page_cache_alloc(mapping_gfp_mask(mapping) & ~__GFP_FS); |
| 845 | if (page && add_to_page_cache_lru(page, mapping, index, GFP_KERNEL)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 846 | page_cache_release(page); |
| 847 | page = NULL; |
| 848 | } |
| 849 | return page; |
| 850 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 851 | EXPORT_SYMBOL(grab_cache_page_nowait); |
| 852 | |
Wu Fengguang | 76d42bd | 2006-06-25 05:48:43 -0700 | [diff] [blame] | 853 | /* |
| 854 | * CD/DVDs are error prone. When a medium error occurs, the driver may fail |
| 855 | * a _large_ part of the i/o request. Imagine the worst scenario: |
| 856 | * |
| 857 | * ---R__________________________________________B__________ |
| 858 | * ^ reading here ^ bad block(assume 4k) |
| 859 | * |
| 860 | * read(R) => miss => readahead(R...B) => media error => frustrating retries |
| 861 | * => failing the whole request => read(R) => read(R+1) => |
| 862 | * readahead(R+1...B+1) => bang => read(R+2) => read(R+3) => |
| 863 | * readahead(R+3...B+2) => bang => read(R+3) => read(R+4) => |
| 864 | * readahead(R+4...B+3) => bang => read(R+4) => read(R+5) => ...... |
| 865 | * |
| 866 | * It is going insane. Fix it by quickly scaling down the readahead size. |
| 867 | */ |
| 868 | static void shrink_readahead_size_eio(struct file *filp, |
| 869 | struct file_ra_state *ra) |
| 870 | { |
| 871 | if (!ra->ra_pages) |
| 872 | return; |
| 873 | |
| 874 | ra->ra_pages /= 4; |
Wu Fengguang | 76d42bd | 2006-06-25 05:48:43 -0700 | [diff] [blame] | 875 | } |
| 876 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 877 | /** |
Christoph Hellwig | 36e7891 | 2008-02-08 04:21:24 -0800 | [diff] [blame] | 878 | * do_generic_file_read - generic file read routine |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 879 | * @filp: the file to read |
| 880 | * @ppos: current file position |
| 881 | * @desc: read_descriptor |
| 882 | * @actor: read method |
| 883 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 884 | * This is a generic file read routine, and uses the |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 885 | * mapping->a_ops->readpage() function for the actual low-level stuff. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 886 | * |
| 887 | * This is really ugly. But the goto's actually try to clarify some |
| 888 | * of the logic when it comes to error handling etc. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 889 | */ |
Christoph Hellwig | 36e7891 | 2008-02-08 04:21:24 -0800 | [diff] [blame] | 890 | static void do_generic_file_read(struct file *filp, loff_t *ppos, |
| 891 | read_descriptor_t *desc, read_actor_t actor) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 892 | { |
Christoph Hellwig | 36e7891 | 2008-02-08 04:21:24 -0800 | [diff] [blame] | 893 | struct address_space *mapping = filp->f_mapping; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 894 | struct inode *inode = mapping->host; |
Christoph Hellwig | 36e7891 | 2008-02-08 04:21:24 -0800 | [diff] [blame] | 895 | struct file_ra_state *ra = &filp->f_ra; |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 896 | pgoff_t index; |
| 897 | pgoff_t last_index; |
| 898 | pgoff_t prev_index; |
| 899 | unsigned long offset; /* offset into pagecache page */ |
Jan Kara | ec0f163 | 2007-05-06 14:49:25 -0700 | [diff] [blame] | 900 | unsigned int prev_offset; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 901 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 902 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 903 | index = *ppos >> PAGE_CACHE_SHIFT; |
Fengguang Wu | 7ff8107 | 2007-10-16 01:24:35 -0700 | [diff] [blame] | 904 | prev_index = ra->prev_pos >> PAGE_CACHE_SHIFT; |
| 905 | prev_offset = ra->prev_pos & (PAGE_CACHE_SIZE-1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 906 | last_index = (*ppos + desc->count + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT; |
| 907 | offset = *ppos & ~PAGE_CACHE_MASK; |
| 908 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 909 | for (;;) { |
| 910 | struct page *page; |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 911 | pgoff_t end_index; |
NeilBrown | a32ea1e | 2007-07-17 04:03:04 -0700 | [diff] [blame] | 912 | loff_t isize; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 913 | unsigned long nr, ret; |
| 914 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 915 | cond_resched(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 916 | find_page: |
| 917 | page = find_get_page(mapping, index); |
Fengguang Wu | 3ea89ee | 2007-07-19 01:48:02 -0700 | [diff] [blame] | 918 | if (!page) { |
Rusty Russell | cf914a7 | 2007-07-19 01:48:08 -0700 | [diff] [blame] | 919 | page_cache_sync_readahead(mapping, |
Fengguang Wu | 7ff8107 | 2007-10-16 01:24:35 -0700 | [diff] [blame] | 920 | ra, filp, |
Fengguang Wu | 3ea89ee | 2007-07-19 01:48:02 -0700 | [diff] [blame] | 921 | index, last_index - index); |
| 922 | page = find_get_page(mapping, index); |
| 923 | if (unlikely(page == NULL)) |
| 924 | goto no_cached_page; |
| 925 | } |
| 926 | if (PageReadahead(page)) { |
Rusty Russell | cf914a7 | 2007-07-19 01:48:08 -0700 | [diff] [blame] | 927 | page_cache_async_readahead(mapping, |
Fengguang Wu | 7ff8107 | 2007-10-16 01:24:35 -0700 | [diff] [blame] | 928 | ra, filp, page, |
Fengguang Wu | 3ea89ee | 2007-07-19 01:48:02 -0700 | [diff] [blame] | 929 | index, last_index - index); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 930 | } |
| 931 | if (!PageUptodate(page)) |
| 932 | goto page_not_up_to_date; |
| 933 | page_ok: |
NeilBrown | a32ea1e | 2007-07-17 04:03:04 -0700 | [diff] [blame] | 934 | /* |
| 935 | * i_size must be checked after we know the page is Uptodate. |
| 936 | * |
| 937 | * Checking i_size after the check allows us to calculate |
| 938 | * the correct value for "nr", which means the zero-filled |
| 939 | * part of the page is not copied back to userspace (unless |
| 940 | * another truncate extends the file - this is desired though). |
| 941 | */ |
| 942 | |
| 943 | isize = i_size_read(inode); |
| 944 | end_index = (isize - 1) >> PAGE_CACHE_SHIFT; |
| 945 | if (unlikely(!isize || index > end_index)) { |
| 946 | page_cache_release(page); |
| 947 | goto out; |
| 948 | } |
| 949 | |
| 950 | /* nr is the maximum number of bytes to copy from this page */ |
| 951 | nr = PAGE_CACHE_SIZE; |
| 952 | if (index == end_index) { |
| 953 | nr = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; |
| 954 | if (nr <= offset) { |
| 955 | page_cache_release(page); |
| 956 | goto out; |
| 957 | } |
| 958 | } |
| 959 | nr = nr - offset; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 960 | |
| 961 | /* If users can be writing to this page using arbitrary |
| 962 | * virtual addresses, take care about potential aliasing |
| 963 | * before reading the page on the kernel side. |
| 964 | */ |
| 965 | if (mapping_writably_mapped(mapping)) |
| 966 | flush_dcache_page(page); |
| 967 | |
| 968 | /* |
Jan Kara | ec0f163 | 2007-05-06 14:49:25 -0700 | [diff] [blame] | 969 | * When a sequential read accesses a page several times, |
| 970 | * only mark it as accessed the first time. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 971 | */ |
Jan Kara | ec0f163 | 2007-05-06 14:49:25 -0700 | [diff] [blame] | 972 | if (prev_index != index || offset != prev_offset) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 973 | mark_page_accessed(page); |
| 974 | prev_index = index; |
| 975 | |
| 976 | /* |
| 977 | * Ok, we have the page, and it's up-to-date, so |
| 978 | * now we can copy it to user space... |
| 979 | * |
| 980 | * The actor routine returns how many bytes were actually used.. |
| 981 | * NOTE! This may not be the same as how much of a user buffer |
| 982 | * we filled up (we may be padding etc), so we can only update |
| 983 | * "pos" here (the actor routine has to update the user buffer |
| 984 | * pointers and the remaining count). |
| 985 | */ |
| 986 | ret = actor(desc, page, offset, nr); |
| 987 | offset += ret; |
| 988 | index += offset >> PAGE_CACHE_SHIFT; |
| 989 | offset &= ~PAGE_CACHE_MASK; |
Jan Kara | 6ce745e | 2007-05-06 14:49:26 -0700 | [diff] [blame] | 990 | prev_offset = offset; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 991 | |
| 992 | page_cache_release(page); |
| 993 | if (ret == nr && desc->count) |
| 994 | continue; |
| 995 | goto out; |
| 996 | |
| 997 | page_not_up_to_date: |
| 998 | /* Get exclusive access to the page ... */ |
Matthew Wilcox | 0b94e97 | 2007-12-06 11:19:57 -0500 | [diff] [blame] | 999 | if (lock_page_killable(page)) |
| 1000 | goto readpage_eio; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1001 | |
Nick Piggin | da6052f | 2006-09-25 23:31:35 -0700 | [diff] [blame] | 1002 | /* Did it get truncated before we got the lock? */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1003 | if (!page->mapping) { |
| 1004 | unlock_page(page); |
| 1005 | page_cache_release(page); |
| 1006 | continue; |
| 1007 | } |
| 1008 | |
| 1009 | /* Did somebody else fill it already? */ |
| 1010 | if (PageUptodate(page)) { |
| 1011 | unlock_page(page); |
| 1012 | goto page_ok; |
| 1013 | } |
| 1014 | |
| 1015 | readpage: |
| 1016 | /* Start the actual read. The read will unlock the page. */ |
| 1017 | error = mapping->a_ops->readpage(filp, page); |
| 1018 | |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 1019 | if (unlikely(error)) { |
| 1020 | if (error == AOP_TRUNCATED_PAGE) { |
| 1021 | page_cache_release(page); |
| 1022 | goto find_page; |
| 1023 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1024 | goto readpage_error; |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 1025 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1026 | |
| 1027 | if (!PageUptodate(page)) { |
Matthew Wilcox | 0b94e97 | 2007-12-06 11:19:57 -0500 | [diff] [blame] | 1028 | if (lock_page_killable(page)) |
| 1029 | goto readpage_eio; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1030 | if (!PageUptodate(page)) { |
| 1031 | if (page->mapping == NULL) { |
| 1032 | /* |
| 1033 | * invalidate_inode_pages got it |
| 1034 | */ |
| 1035 | unlock_page(page); |
| 1036 | page_cache_release(page); |
| 1037 | goto find_page; |
| 1038 | } |
| 1039 | unlock_page(page); |
Fengguang Wu | 7ff8107 | 2007-10-16 01:24:35 -0700 | [diff] [blame] | 1040 | shrink_readahead_size_eio(filp, ra); |
Matthew Wilcox | 0b94e97 | 2007-12-06 11:19:57 -0500 | [diff] [blame] | 1041 | goto readpage_eio; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1042 | } |
| 1043 | unlock_page(page); |
| 1044 | } |
| 1045 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1046 | goto page_ok; |
| 1047 | |
Matthew Wilcox | 0b94e97 | 2007-12-06 11:19:57 -0500 | [diff] [blame] | 1048 | readpage_eio: |
| 1049 | error = -EIO; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1050 | readpage_error: |
| 1051 | /* UHHUH! A synchronous read error occurred. Report it */ |
| 1052 | desc->error = error; |
| 1053 | page_cache_release(page); |
| 1054 | goto out; |
| 1055 | |
| 1056 | no_cached_page: |
| 1057 | /* |
| 1058 | * Ok, it wasn't cached, so we need to create a new |
| 1059 | * page.. |
| 1060 | */ |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 1061 | page = page_cache_alloc_cold(mapping); |
| 1062 | if (!page) { |
| 1063 | desc->error = -ENOMEM; |
| 1064 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1065 | } |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 1066 | error = add_to_page_cache_lru(page, mapping, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1067 | index, GFP_KERNEL); |
| 1068 | if (error) { |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 1069 | page_cache_release(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1070 | if (error == -EEXIST) |
| 1071 | goto find_page; |
| 1072 | desc->error = error; |
| 1073 | goto out; |
| 1074 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1075 | goto readpage; |
| 1076 | } |
| 1077 | |
| 1078 | out: |
Fengguang Wu | 7ff8107 | 2007-10-16 01:24:35 -0700 | [diff] [blame] | 1079 | ra->prev_pos = prev_index; |
| 1080 | ra->prev_pos <<= PAGE_CACHE_SHIFT; |
| 1081 | ra->prev_pos |= prev_offset; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1082 | |
Fengguang Wu | f4e6b49 | 2007-10-16 01:24:33 -0700 | [diff] [blame] | 1083 | *ppos = ((loff_t)index << PAGE_CACHE_SHIFT) + offset; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1084 | if (filp) |
| 1085 | file_accessed(filp); |
| 1086 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1087 | |
| 1088 | int file_read_actor(read_descriptor_t *desc, struct page *page, |
| 1089 | unsigned long offset, unsigned long size) |
| 1090 | { |
| 1091 | char *kaddr; |
| 1092 | unsigned long left, count = desc->count; |
| 1093 | |
| 1094 | if (size > count) |
| 1095 | size = count; |
| 1096 | |
| 1097 | /* |
| 1098 | * Faults on the destination of a read are common, so do it before |
| 1099 | * taking the kmap. |
| 1100 | */ |
| 1101 | if (!fault_in_pages_writeable(desc->arg.buf, size)) { |
| 1102 | kaddr = kmap_atomic(page, KM_USER0); |
| 1103 | left = __copy_to_user_inatomic(desc->arg.buf, |
| 1104 | kaddr + offset, size); |
| 1105 | kunmap_atomic(kaddr, KM_USER0); |
| 1106 | if (left == 0) |
| 1107 | goto success; |
| 1108 | } |
| 1109 | |
| 1110 | /* Do it the slow way */ |
| 1111 | kaddr = kmap(page); |
| 1112 | left = __copy_to_user(desc->arg.buf, kaddr + offset, size); |
| 1113 | kunmap(page); |
| 1114 | |
| 1115 | if (left) { |
| 1116 | size -= left; |
| 1117 | desc->error = -EFAULT; |
| 1118 | } |
| 1119 | success: |
| 1120 | desc->count = count - size; |
| 1121 | desc->written += size; |
| 1122 | desc->arg.buf += size; |
| 1123 | return size; |
| 1124 | } |
| 1125 | |
Dmitriy Monakhov | 0ceb331 | 2007-05-08 00:23:02 -0700 | [diff] [blame] | 1126 | /* |
| 1127 | * Performs necessary checks before doing a write |
| 1128 | * @iov: io vector request |
| 1129 | * @nr_segs: number of segments in the iovec |
| 1130 | * @count: number of bytes to write |
| 1131 | * @access_flags: type of access: %VERIFY_READ or %VERIFY_WRITE |
| 1132 | * |
| 1133 | * Adjust number of segments and amount of bytes to write (nr_segs should be |
| 1134 | * properly initialized first). Returns appropriate error code that caller |
| 1135 | * should return or zero in case that write should be allowed. |
| 1136 | */ |
| 1137 | int generic_segment_checks(const struct iovec *iov, |
| 1138 | unsigned long *nr_segs, size_t *count, int access_flags) |
| 1139 | { |
| 1140 | unsigned long seg; |
| 1141 | size_t cnt = 0; |
| 1142 | for (seg = 0; seg < *nr_segs; seg++) { |
| 1143 | const struct iovec *iv = &iov[seg]; |
| 1144 | |
| 1145 | /* |
| 1146 | * If any segment has a negative length, or the cumulative |
| 1147 | * length ever wraps negative then return -EINVAL. |
| 1148 | */ |
| 1149 | cnt += iv->iov_len; |
| 1150 | if (unlikely((ssize_t)(cnt|iv->iov_len) < 0)) |
| 1151 | return -EINVAL; |
| 1152 | if (access_ok(access_flags, iv->iov_base, iv->iov_len)) |
| 1153 | continue; |
| 1154 | if (seg == 0) |
| 1155 | return -EFAULT; |
| 1156 | *nr_segs = seg; |
| 1157 | cnt -= iv->iov_len; /* This segment is no good */ |
| 1158 | break; |
| 1159 | } |
| 1160 | *count = cnt; |
| 1161 | return 0; |
| 1162 | } |
| 1163 | EXPORT_SYMBOL(generic_segment_checks); |
| 1164 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 1165 | /** |
Henrik Kretzschmar | b2abacf | 2006-10-04 02:15:22 -0700 | [diff] [blame] | 1166 | * generic_file_aio_read - generic filesystem read routine |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 1167 | * @iocb: kernel I/O control block |
| 1168 | * @iov: io vector request |
| 1169 | * @nr_segs: number of segments in the iovec |
Henrik Kretzschmar | b2abacf | 2006-10-04 02:15:22 -0700 | [diff] [blame] | 1170 | * @pos: current file position |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 1171 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1172 | * This is the "read()" routine for all filesystems |
| 1173 | * that can use the page cache directly. |
| 1174 | */ |
| 1175 | ssize_t |
Badari Pulavarty | 543ade1 | 2006-09-30 23:28:48 -0700 | [diff] [blame] | 1176 | generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, |
| 1177 | unsigned long nr_segs, loff_t pos) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1178 | { |
| 1179 | struct file *filp = iocb->ki_filp; |
| 1180 | ssize_t retval; |
| 1181 | unsigned long seg; |
| 1182 | size_t count; |
Badari Pulavarty | 543ade1 | 2006-09-30 23:28:48 -0700 | [diff] [blame] | 1183 | loff_t *ppos = &iocb->ki_pos; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1184 | |
| 1185 | count = 0; |
Dmitriy Monakhov | 0ceb331 | 2007-05-08 00:23:02 -0700 | [diff] [blame] | 1186 | retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE); |
| 1187 | if (retval) |
| 1188 | return retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1189 | |
| 1190 | /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */ |
| 1191 | if (filp->f_flags & O_DIRECT) { |
Badari Pulavarty | 543ade1 | 2006-09-30 23:28:48 -0700 | [diff] [blame] | 1192 | loff_t size; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1193 | struct address_space *mapping; |
| 1194 | struct inode *inode; |
| 1195 | |
| 1196 | mapping = filp->f_mapping; |
| 1197 | inode = mapping->host; |
| 1198 | retval = 0; |
| 1199 | if (!count) |
| 1200 | goto out; /* skip atime */ |
| 1201 | size = i_size_read(inode); |
| 1202 | if (pos < size) { |
| 1203 | retval = generic_file_direct_IO(READ, iocb, |
| 1204 | iov, pos, nr_segs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1205 | if (retval > 0) |
| 1206 | *ppos = pos + retval; |
| 1207 | } |
Steven Whitehouse | 0e0bcae | 2006-09-27 14:45:07 -0400 | [diff] [blame] | 1208 | if (likely(retval != 0)) { |
Steven Whitehouse | 3f1a9aa | 2006-09-27 14:52:48 -0400 | [diff] [blame] | 1209 | file_accessed(filp); |
Steven Whitehouse | a9e5f4d | 2006-07-25 17:24:12 -0400 | [diff] [blame] | 1210 | goto out; |
Steven Whitehouse | 0e0bcae | 2006-09-27 14:45:07 -0400 | [diff] [blame] | 1211 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1212 | } |
| 1213 | |
| 1214 | retval = 0; |
| 1215 | if (count) { |
| 1216 | for (seg = 0; seg < nr_segs; seg++) { |
| 1217 | read_descriptor_t desc; |
| 1218 | |
| 1219 | desc.written = 0; |
| 1220 | desc.arg.buf = iov[seg].iov_base; |
| 1221 | desc.count = iov[seg].iov_len; |
| 1222 | if (desc.count == 0) |
| 1223 | continue; |
| 1224 | desc.error = 0; |
| 1225 | do_generic_file_read(filp,ppos,&desc,file_read_actor); |
| 1226 | retval += desc.written; |
Tejun Heo | 39e88ca | 2005-10-30 15:02:40 -0800 | [diff] [blame] | 1227 | if (desc.error) { |
| 1228 | retval = retval ?: desc.error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1229 | break; |
| 1230 | } |
akpm@linux-foundation.org | c44939e | 2007-07-15 23:38:25 -0700 | [diff] [blame] | 1231 | if (desc.count > 0) |
| 1232 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1233 | } |
| 1234 | } |
| 1235 | out: |
| 1236 | return retval; |
| 1237 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1238 | EXPORT_SYMBOL(generic_file_aio_read); |
| 1239 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1240 | static ssize_t |
| 1241 | do_readahead(struct address_space *mapping, struct file *filp, |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 1242 | pgoff_t index, unsigned long nr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1243 | { |
| 1244 | if (!mapping || !mapping->a_ops || !mapping->a_ops->readpage) |
| 1245 | return -EINVAL; |
| 1246 | |
| 1247 | force_page_cache_readahead(mapping, filp, index, |
| 1248 | max_sane_readahead(nr)); |
| 1249 | return 0; |
| 1250 | } |
| 1251 | |
| 1252 | asmlinkage ssize_t sys_readahead(int fd, loff_t offset, size_t count) |
| 1253 | { |
| 1254 | ssize_t ret; |
| 1255 | struct file *file; |
| 1256 | |
| 1257 | ret = -EBADF; |
| 1258 | file = fget(fd); |
| 1259 | if (file) { |
| 1260 | if (file->f_mode & FMODE_READ) { |
| 1261 | struct address_space *mapping = file->f_mapping; |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 1262 | pgoff_t start = offset >> PAGE_CACHE_SHIFT; |
| 1263 | pgoff_t end = (offset + count - 1) >> PAGE_CACHE_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1264 | unsigned long len = end - start + 1; |
| 1265 | ret = do_readahead(mapping, file, start, len); |
| 1266 | } |
| 1267 | fput(file); |
| 1268 | } |
| 1269 | return ret; |
| 1270 | } |
| 1271 | |
| 1272 | #ifdef CONFIG_MMU |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 1273 | /** |
| 1274 | * page_cache_read - adds requested page to the page cache if not already there |
| 1275 | * @file: file to read |
| 1276 | * @offset: page index |
| 1277 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1278 | * This adds the requested page to the page cache if it isn't already there, |
| 1279 | * and schedules an I/O to read in its contents from disk. |
| 1280 | */ |
Harvey Harrison | 920c7a5 | 2008-02-04 22:29:26 -0800 | [diff] [blame] | 1281 | static int page_cache_read(struct file *file, pgoff_t offset) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1282 | { |
| 1283 | struct address_space *mapping = file->f_mapping; |
| 1284 | struct page *page; |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 1285 | int ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1286 | |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 1287 | do { |
| 1288 | page = page_cache_alloc_cold(mapping); |
| 1289 | if (!page) |
| 1290 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1291 | |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 1292 | ret = add_to_page_cache_lru(page, mapping, offset, GFP_KERNEL); |
| 1293 | if (ret == 0) |
| 1294 | ret = mapping->a_ops->readpage(file, page); |
| 1295 | else if (ret == -EEXIST) |
| 1296 | ret = 0; /* losing race to add is OK */ |
| 1297 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1298 | page_cache_release(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1299 | |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 1300 | } while (ret == AOP_TRUNCATED_PAGE); |
| 1301 | |
| 1302 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1303 | } |
| 1304 | |
| 1305 | #define MMAP_LOTSAMISS (100) |
| 1306 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 1307 | /** |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 1308 | * filemap_fault - read in file data for page fault handling |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1309 | * @vma: vma in which the fault was taken |
| 1310 | * @vmf: struct vm_fault containing details of the fault |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 1311 | * |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 1312 | * filemap_fault() is invoked via the vma operations vector for a |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1313 | * mapped memory region to read in file data during a page fault. |
| 1314 | * |
| 1315 | * The goto's are kind of ugly, but this streamlines the normal case of having |
| 1316 | * it in the page cache, and handles the special cases reasonably without |
| 1317 | * having a lot of duplicated code. |
| 1318 | */ |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1319 | int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1320 | { |
| 1321 | int error; |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 1322 | struct file *file = vma->vm_file; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1323 | struct address_space *mapping = file->f_mapping; |
| 1324 | struct file_ra_state *ra = &file->f_ra; |
| 1325 | struct inode *inode = mapping->host; |
| 1326 | struct page *page; |
Jan Kara | 2004dc8 | 2008-02-08 04:20:11 -0800 | [diff] [blame] | 1327 | pgoff_t size; |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 1328 | int did_readaround = 0; |
Nick Piggin | 83c5407 | 2007-07-19 01:47:05 -0700 | [diff] [blame] | 1329 | int ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1330 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1331 | size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1332 | if (vmf->pgoff >= size) |
Linus Torvalds | 5307cc1 | 2007-10-31 09:19:46 -0700 | [diff] [blame] | 1333 | return VM_FAULT_SIGBUS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1334 | |
| 1335 | /* If we don't want any read-ahead, don't bother */ |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 1336 | if (VM_RandomReadHint(vma)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1337 | goto no_cached_page; |
| 1338 | |
| 1339 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1340 | * Do we have something in the page cache already? |
| 1341 | */ |
| 1342 | retry_find: |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1343 | page = find_lock_page(mapping, vmf->pgoff); |
Fengguang Wu | 3ea89ee | 2007-07-19 01:48:02 -0700 | [diff] [blame] | 1344 | /* |
| 1345 | * For sequential accesses, we use the generic readahead logic. |
| 1346 | */ |
| 1347 | if (VM_SequentialReadHint(vma)) { |
| 1348 | if (!page) { |
Rusty Russell | cf914a7 | 2007-07-19 01:48:08 -0700 | [diff] [blame] | 1349 | page_cache_sync_readahead(mapping, ra, file, |
Fengguang Wu | 3ea89ee | 2007-07-19 01:48:02 -0700 | [diff] [blame] | 1350 | vmf->pgoff, 1); |
| 1351 | page = find_lock_page(mapping, vmf->pgoff); |
| 1352 | if (!page) |
| 1353 | goto no_cached_page; |
| 1354 | } |
| 1355 | if (PageReadahead(page)) { |
Rusty Russell | cf914a7 | 2007-07-19 01:48:08 -0700 | [diff] [blame] | 1356 | page_cache_async_readahead(mapping, ra, file, page, |
Fengguang Wu | 3ea89ee | 2007-07-19 01:48:02 -0700 | [diff] [blame] | 1357 | vmf->pgoff, 1); |
| 1358 | } |
| 1359 | } |
| 1360 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1361 | if (!page) { |
| 1362 | unsigned long ra_pages; |
| 1363 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1364 | ra->mmap_miss++; |
| 1365 | |
| 1366 | /* |
| 1367 | * Do we miss much more than hit in this file? If so, |
| 1368 | * stop bothering with read-ahead. It will only hurt. |
| 1369 | */ |
Fengguang Wu | 0bb7ba6 | 2007-10-16 01:24:32 -0700 | [diff] [blame] | 1370 | if (ra->mmap_miss > MMAP_LOTSAMISS) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1371 | goto no_cached_page; |
| 1372 | |
| 1373 | /* |
| 1374 | * To keep the pgmajfault counter straight, we need to |
| 1375 | * check did_readaround, as this is an inner loop. |
| 1376 | */ |
| 1377 | if (!did_readaround) { |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1378 | ret = VM_FAULT_MAJOR; |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 1379 | count_vm_event(PGMAJFAULT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1380 | } |
| 1381 | did_readaround = 1; |
| 1382 | ra_pages = max_sane_readahead(file->f_ra.ra_pages); |
| 1383 | if (ra_pages) { |
| 1384 | pgoff_t start = 0; |
| 1385 | |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1386 | if (vmf->pgoff > ra_pages / 2) |
| 1387 | start = vmf->pgoff - ra_pages / 2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1388 | do_page_cache_readahead(mapping, file, start, ra_pages); |
| 1389 | } |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1390 | page = find_lock_page(mapping, vmf->pgoff); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1391 | if (!page) |
| 1392 | goto no_cached_page; |
| 1393 | } |
| 1394 | |
| 1395 | if (!did_readaround) |
Fengguang Wu | 0bb7ba6 | 2007-10-16 01:24:32 -0700 | [diff] [blame] | 1396 | ra->mmap_miss--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1397 | |
| 1398 | /* |
Nick Piggin | d00806b | 2007-07-19 01:46:57 -0700 | [diff] [blame] | 1399 | * We have a locked page in the page cache, now we need to check |
| 1400 | * that it's up-to-date. If not, it is going to be due to an error. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1401 | */ |
Nick Piggin | d00806b | 2007-07-19 01:46:57 -0700 | [diff] [blame] | 1402 | if (unlikely(!PageUptodate(page))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1403 | goto page_not_uptodate; |
| 1404 | |
Nick Piggin | d00806b | 2007-07-19 01:46:57 -0700 | [diff] [blame] | 1405 | /* Must recheck i_size under page lock */ |
| 1406 | size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1407 | if (unlikely(vmf->pgoff >= size)) { |
Nick Piggin | d00806b | 2007-07-19 01:46:57 -0700 | [diff] [blame] | 1408 | unlock_page(page); |
Yan Zheng | 745ad48 | 2007-10-08 10:08:37 -0700 | [diff] [blame] | 1409 | page_cache_release(page); |
Linus Torvalds | 5307cc1 | 2007-10-31 09:19:46 -0700 | [diff] [blame] | 1410 | return VM_FAULT_SIGBUS; |
Nick Piggin | d00806b | 2007-07-19 01:46:57 -0700 | [diff] [blame] | 1411 | } |
| 1412 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1413 | /* |
| 1414 | * Found the page and have a reference on it. |
| 1415 | */ |
| 1416 | mark_page_accessed(page); |
Fengguang Wu | f4e6b49 | 2007-10-16 01:24:33 -0700 | [diff] [blame] | 1417 | ra->prev_pos = (loff_t)page->index << PAGE_CACHE_SHIFT; |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1418 | vmf->page = page; |
Nick Piggin | 83c5407 | 2007-07-19 01:47:05 -0700 | [diff] [blame] | 1419 | return ret | VM_FAULT_LOCKED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1420 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1421 | no_cached_page: |
| 1422 | /* |
| 1423 | * We're only likely to ever get here if MADV_RANDOM is in |
| 1424 | * effect. |
| 1425 | */ |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1426 | error = page_cache_read(file, vmf->pgoff); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1427 | |
| 1428 | /* |
| 1429 | * The page we want has now been added to the page cache. |
| 1430 | * In the unlikely event that someone removed it in the |
| 1431 | * meantime, we'll just come back here and read it again. |
| 1432 | */ |
| 1433 | if (error >= 0) |
| 1434 | goto retry_find; |
| 1435 | |
| 1436 | /* |
| 1437 | * An error return from page_cache_read can result if the |
| 1438 | * system is low on memory, or a problem occurs while trying |
| 1439 | * to schedule I/O. |
| 1440 | */ |
| 1441 | if (error == -ENOMEM) |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1442 | return VM_FAULT_OOM; |
| 1443 | return VM_FAULT_SIGBUS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1444 | |
| 1445 | page_not_uptodate: |
Nick Piggin | d00806b | 2007-07-19 01:46:57 -0700 | [diff] [blame] | 1446 | /* IO error path */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1447 | if (!did_readaround) { |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1448 | ret = VM_FAULT_MAJOR; |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 1449 | count_vm_event(PGMAJFAULT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1450 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1451 | |
| 1452 | /* |
| 1453 | * Umm, take care of errors if the page isn't up-to-date. |
| 1454 | * Try to re-read it _once_. We do this synchronously, |
| 1455 | * because there really aren't any performance issues here |
| 1456 | * and we need to check for errors. |
| 1457 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1458 | ClearPageError(page); |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 1459 | error = mapping->a_ops->readpage(file, page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1460 | page_cache_release(page); |
Nick Piggin | d00806b | 2007-07-19 01:46:57 -0700 | [diff] [blame] | 1461 | |
| 1462 | if (!error || error == AOP_TRUNCATED_PAGE) |
| 1463 | goto retry_find; |
| 1464 | |
| 1465 | /* Things didn't work out. Return zero to tell the mm layer so. */ |
| 1466 | shrink_readahead_size_eio(file, ra); |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1467 | return VM_FAULT_SIGBUS; |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 1468 | } |
| 1469 | EXPORT_SYMBOL(filemap_fault); |
| 1470 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1471 | struct vm_operations_struct generic_file_vm_ops = { |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 1472 | .fault = filemap_fault, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1473 | }; |
| 1474 | |
| 1475 | /* This is used for a general mmap of a disk file */ |
| 1476 | |
| 1477 | int generic_file_mmap(struct file * file, struct vm_area_struct * vma) |
| 1478 | { |
| 1479 | struct address_space *mapping = file->f_mapping; |
| 1480 | |
| 1481 | if (!mapping->a_ops->readpage) |
| 1482 | return -ENOEXEC; |
| 1483 | file_accessed(file); |
| 1484 | vma->vm_ops = &generic_file_vm_ops; |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1485 | vma->vm_flags |= VM_CAN_NONLINEAR; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1486 | return 0; |
| 1487 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1488 | |
| 1489 | /* |
| 1490 | * This is for filesystems which do not implement ->writepage. |
| 1491 | */ |
| 1492 | int generic_file_readonly_mmap(struct file *file, struct vm_area_struct *vma) |
| 1493 | { |
| 1494 | if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) |
| 1495 | return -EINVAL; |
| 1496 | return generic_file_mmap(file, vma); |
| 1497 | } |
| 1498 | #else |
| 1499 | int generic_file_mmap(struct file * file, struct vm_area_struct * vma) |
| 1500 | { |
| 1501 | return -ENOSYS; |
| 1502 | } |
| 1503 | int generic_file_readonly_mmap(struct file * file, struct vm_area_struct * vma) |
| 1504 | { |
| 1505 | return -ENOSYS; |
| 1506 | } |
| 1507 | #endif /* CONFIG_MMU */ |
| 1508 | |
| 1509 | EXPORT_SYMBOL(generic_file_mmap); |
| 1510 | EXPORT_SYMBOL(generic_file_readonly_mmap); |
| 1511 | |
Nick Piggin | 6fe6900 | 2007-05-06 14:49:04 -0700 | [diff] [blame] | 1512 | static struct page *__read_cache_page(struct address_space *mapping, |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 1513 | pgoff_t index, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1514 | int (*filler)(void *,struct page*), |
| 1515 | void *data) |
| 1516 | { |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 1517 | struct page *page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1518 | int err; |
| 1519 | repeat: |
| 1520 | page = find_get_page(mapping, index); |
| 1521 | if (!page) { |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 1522 | page = page_cache_alloc_cold(mapping); |
| 1523 | if (!page) |
| 1524 | return ERR_PTR(-ENOMEM); |
| 1525 | err = add_to_page_cache_lru(page, mapping, index, GFP_KERNEL); |
| 1526 | if (unlikely(err)) { |
| 1527 | page_cache_release(page); |
| 1528 | if (err == -EEXIST) |
| 1529 | goto repeat; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1530 | /* Presumably ENOMEM for radix tree node */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1531 | return ERR_PTR(err); |
| 1532 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1533 | err = filler(data, page); |
| 1534 | if (err < 0) { |
| 1535 | page_cache_release(page); |
| 1536 | page = ERR_PTR(err); |
| 1537 | } |
| 1538 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1539 | return page; |
| 1540 | } |
| 1541 | |
Nick Piggin | 6fe6900 | 2007-05-06 14:49:04 -0700 | [diff] [blame] | 1542 | /* |
| 1543 | * Same as read_cache_page, but don't wait for page to become unlocked |
| 1544 | * after submitting it to the filler. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1545 | */ |
Nick Piggin | 6fe6900 | 2007-05-06 14:49:04 -0700 | [diff] [blame] | 1546 | struct page *read_cache_page_async(struct address_space *mapping, |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 1547 | pgoff_t index, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1548 | int (*filler)(void *,struct page*), |
| 1549 | void *data) |
| 1550 | { |
| 1551 | struct page *page; |
| 1552 | int err; |
| 1553 | |
| 1554 | retry: |
| 1555 | page = __read_cache_page(mapping, index, filler, data); |
| 1556 | if (IS_ERR(page)) |
David Howells | c855ff3 | 2007-05-09 13:42:20 +0100 | [diff] [blame] | 1557 | return page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1558 | if (PageUptodate(page)) |
| 1559 | goto out; |
| 1560 | |
| 1561 | lock_page(page); |
| 1562 | if (!page->mapping) { |
| 1563 | unlock_page(page); |
| 1564 | page_cache_release(page); |
| 1565 | goto retry; |
| 1566 | } |
| 1567 | if (PageUptodate(page)) { |
| 1568 | unlock_page(page); |
| 1569 | goto out; |
| 1570 | } |
| 1571 | err = filler(data, page); |
| 1572 | if (err < 0) { |
| 1573 | page_cache_release(page); |
David Howells | c855ff3 | 2007-05-09 13:42:20 +0100 | [diff] [blame] | 1574 | return ERR_PTR(err); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1575 | } |
David Howells | c855ff3 | 2007-05-09 13:42:20 +0100 | [diff] [blame] | 1576 | out: |
Nick Piggin | 6fe6900 | 2007-05-06 14:49:04 -0700 | [diff] [blame] | 1577 | mark_page_accessed(page); |
| 1578 | return page; |
| 1579 | } |
| 1580 | EXPORT_SYMBOL(read_cache_page_async); |
| 1581 | |
| 1582 | /** |
| 1583 | * read_cache_page - read into page cache, fill it if needed |
| 1584 | * @mapping: the page's address_space |
| 1585 | * @index: the page index |
| 1586 | * @filler: function to perform the read |
| 1587 | * @data: destination for read data |
| 1588 | * |
| 1589 | * Read into the page cache. If a page already exists, and PageUptodate() is |
| 1590 | * not set, try to fill the page then wait for it to become unlocked. |
| 1591 | * |
| 1592 | * If the page does not get brought uptodate, return -EIO. |
| 1593 | */ |
| 1594 | struct page *read_cache_page(struct address_space *mapping, |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 1595 | pgoff_t index, |
Nick Piggin | 6fe6900 | 2007-05-06 14:49:04 -0700 | [diff] [blame] | 1596 | int (*filler)(void *,struct page*), |
| 1597 | void *data) |
| 1598 | { |
| 1599 | struct page *page; |
| 1600 | |
| 1601 | page = read_cache_page_async(mapping, index, filler, data); |
| 1602 | if (IS_ERR(page)) |
| 1603 | goto out; |
| 1604 | wait_on_page_locked(page); |
| 1605 | if (!PageUptodate(page)) { |
| 1606 | page_cache_release(page); |
| 1607 | page = ERR_PTR(-EIO); |
| 1608 | } |
| 1609 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1610 | return page; |
| 1611 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1612 | EXPORT_SYMBOL(read_cache_page); |
| 1613 | |
| 1614 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1615 | * The logic we want is |
| 1616 | * |
| 1617 | * if suid or (sgid and xgrp) |
| 1618 | * remove privs |
| 1619 | */ |
Jens Axboe | 01de85e | 2006-10-17 19:50:36 +0200 | [diff] [blame] | 1620 | int should_remove_suid(struct dentry *dentry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1621 | { |
| 1622 | mode_t mode = dentry->d_inode->i_mode; |
| 1623 | int kill = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1624 | |
| 1625 | /* suid always must be killed */ |
| 1626 | if (unlikely(mode & S_ISUID)) |
| 1627 | kill = ATTR_KILL_SUID; |
| 1628 | |
| 1629 | /* |
| 1630 | * sgid without any exec bits is just a mandatory locking mark; leave |
| 1631 | * it alone. If some exec bits are set, it's a real sgid; kill it. |
| 1632 | */ |
| 1633 | if (unlikely((mode & S_ISGID) && (mode & S_IXGRP))) |
| 1634 | kill |= ATTR_KILL_SGID; |
| 1635 | |
Jens Axboe | 01de85e | 2006-10-17 19:50:36 +0200 | [diff] [blame] | 1636 | if (unlikely(kill && !capable(CAP_FSETID))) |
| 1637 | return kill; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1638 | |
Jens Axboe | 01de85e | 2006-10-17 19:50:36 +0200 | [diff] [blame] | 1639 | return 0; |
| 1640 | } |
Mark Fasheh | d23a147 | 2006-10-17 17:05:18 -0700 | [diff] [blame] | 1641 | EXPORT_SYMBOL(should_remove_suid); |
Jens Axboe | 01de85e | 2006-10-17 19:50:36 +0200 | [diff] [blame] | 1642 | |
| 1643 | int __remove_suid(struct dentry *dentry, int kill) |
| 1644 | { |
| 1645 | struct iattr newattrs; |
| 1646 | |
| 1647 | newattrs.ia_valid = ATTR_FORCE | kill; |
| 1648 | return notify_change(dentry, &newattrs); |
| 1649 | } |
| 1650 | |
| 1651 | int remove_suid(struct dentry *dentry) |
| 1652 | { |
Serge E. Hallyn | b537677 | 2007-10-16 23:31:36 -0700 | [diff] [blame] | 1653 | int killsuid = should_remove_suid(dentry); |
| 1654 | int killpriv = security_inode_need_killpriv(dentry); |
| 1655 | int error = 0; |
Jens Axboe | 01de85e | 2006-10-17 19:50:36 +0200 | [diff] [blame] | 1656 | |
Serge E. Hallyn | b537677 | 2007-10-16 23:31:36 -0700 | [diff] [blame] | 1657 | if (killpriv < 0) |
| 1658 | return killpriv; |
| 1659 | if (killpriv) |
| 1660 | error = security_inode_killpriv(dentry); |
| 1661 | if (!error && killsuid) |
| 1662 | error = __remove_suid(dentry, killsuid); |
Jens Axboe | 01de85e | 2006-10-17 19:50:36 +0200 | [diff] [blame] | 1663 | |
Serge E. Hallyn | b537677 | 2007-10-16 23:31:36 -0700 | [diff] [blame] | 1664 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1665 | } |
| 1666 | EXPORT_SYMBOL(remove_suid); |
| 1667 | |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1668 | static size_t __iovec_copy_from_user_inatomic(char *vaddr, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1669 | const struct iovec *iov, size_t base, size_t bytes) |
| 1670 | { |
| 1671 | size_t copied = 0, left = 0; |
| 1672 | |
| 1673 | while (bytes) { |
| 1674 | char __user *buf = iov->iov_base + base; |
| 1675 | int copy = min(bytes, iov->iov_len - base); |
| 1676 | |
| 1677 | base = 0; |
Hiro Yoshioka | c22ce14 | 2006-06-23 02:04:16 -0700 | [diff] [blame] | 1678 | left = __copy_from_user_inatomic_nocache(vaddr, buf, copy); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1679 | copied += copy; |
| 1680 | bytes -= copy; |
| 1681 | vaddr += copy; |
| 1682 | iov++; |
| 1683 | |
NeilBrown | 01408c4 | 2006-06-25 05:47:58 -0700 | [diff] [blame] | 1684 | if (unlikely(left)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1685 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1686 | } |
| 1687 | return copied - left; |
| 1688 | } |
| 1689 | |
| 1690 | /* |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1691 | * Copy as much as we can into the page and return the number of bytes which |
| 1692 | * were sucessfully copied. If a fault is encountered then return the number of |
| 1693 | * bytes which were copied. |
| 1694 | */ |
| 1695 | size_t iov_iter_copy_from_user_atomic(struct page *page, |
| 1696 | struct iov_iter *i, unsigned long offset, size_t bytes) |
| 1697 | { |
| 1698 | char *kaddr; |
| 1699 | size_t copied; |
| 1700 | |
| 1701 | BUG_ON(!in_atomic()); |
| 1702 | kaddr = kmap_atomic(page, KM_USER0); |
| 1703 | if (likely(i->nr_segs == 1)) { |
| 1704 | int left; |
| 1705 | char __user *buf = i->iov->iov_base + i->iov_offset; |
| 1706 | left = __copy_from_user_inatomic_nocache(kaddr + offset, |
| 1707 | buf, bytes); |
| 1708 | copied = bytes - left; |
| 1709 | } else { |
| 1710 | copied = __iovec_copy_from_user_inatomic(kaddr + offset, |
| 1711 | i->iov, i->iov_offset, bytes); |
| 1712 | } |
| 1713 | kunmap_atomic(kaddr, KM_USER0); |
| 1714 | |
| 1715 | return copied; |
| 1716 | } |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 1717 | EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1718 | |
| 1719 | /* |
| 1720 | * This has the same sideeffects and return value as |
| 1721 | * iov_iter_copy_from_user_atomic(). |
| 1722 | * The difference is that it attempts to resolve faults. |
| 1723 | * Page must not be locked. |
| 1724 | */ |
| 1725 | size_t iov_iter_copy_from_user(struct page *page, |
| 1726 | struct iov_iter *i, unsigned long offset, size_t bytes) |
| 1727 | { |
| 1728 | char *kaddr; |
| 1729 | size_t copied; |
| 1730 | |
| 1731 | kaddr = kmap(page); |
| 1732 | if (likely(i->nr_segs == 1)) { |
| 1733 | int left; |
| 1734 | char __user *buf = i->iov->iov_base + i->iov_offset; |
| 1735 | left = __copy_from_user_nocache(kaddr + offset, buf, bytes); |
| 1736 | copied = bytes - left; |
| 1737 | } else { |
| 1738 | copied = __iovec_copy_from_user_inatomic(kaddr + offset, |
| 1739 | i->iov, i->iov_offset, bytes); |
| 1740 | } |
| 1741 | kunmap(page); |
| 1742 | return copied; |
| 1743 | } |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 1744 | EXPORT_SYMBOL(iov_iter_copy_from_user); |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1745 | |
| 1746 | static void __iov_iter_advance_iov(struct iov_iter *i, size_t bytes) |
| 1747 | { |
| 1748 | if (likely(i->nr_segs == 1)) { |
| 1749 | i->iov_offset += bytes; |
| 1750 | } else { |
| 1751 | const struct iovec *iov = i->iov; |
| 1752 | size_t base = i->iov_offset; |
| 1753 | |
Nick Piggin | 124d3b7 | 2008-02-02 15:01:17 +0100 | [diff] [blame] | 1754 | /* |
| 1755 | * The !iov->iov_len check ensures we skip over unlikely |
| 1756 | * zero-length segments. |
| 1757 | */ |
| 1758 | while (bytes || !iov->iov_len) { |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1759 | int copy = min(bytes, iov->iov_len - base); |
| 1760 | |
| 1761 | bytes -= copy; |
| 1762 | base += copy; |
| 1763 | if (iov->iov_len == base) { |
| 1764 | iov++; |
| 1765 | base = 0; |
| 1766 | } |
| 1767 | } |
| 1768 | i->iov = iov; |
| 1769 | i->iov_offset = base; |
| 1770 | } |
| 1771 | } |
| 1772 | |
| 1773 | void iov_iter_advance(struct iov_iter *i, size_t bytes) |
| 1774 | { |
| 1775 | BUG_ON(i->count < bytes); |
| 1776 | |
| 1777 | __iov_iter_advance_iov(i, bytes); |
| 1778 | i->count -= bytes; |
| 1779 | } |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 1780 | EXPORT_SYMBOL(iov_iter_advance); |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1781 | |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1782 | /* |
| 1783 | * Fault in the first iovec of the given iov_iter, to a maximum length |
| 1784 | * of bytes. Returns 0 on success, or non-zero if the memory could not be |
| 1785 | * accessed (ie. because it is an invalid address). |
| 1786 | * |
| 1787 | * writev-intensive code may want this to prefault several iovecs -- that |
| 1788 | * would be possible (callers must not rely on the fact that _only_ the |
| 1789 | * first iovec will be faulted with the current implementation). |
| 1790 | */ |
| 1791 | int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes) |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1792 | { |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1793 | char __user *buf = i->iov->iov_base + i->iov_offset; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1794 | bytes = min(bytes, i->iov->iov_len - i->iov_offset); |
| 1795 | return fault_in_pages_readable(buf, bytes); |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1796 | } |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 1797 | EXPORT_SYMBOL(iov_iter_fault_in_readable); |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1798 | |
| 1799 | /* |
| 1800 | * Return the count of just the current iov_iter segment. |
| 1801 | */ |
| 1802 | size_t iov_iter_single_seg_count(struct iov_iter *i) |
| 1803 | { |
| 1804 | const struct iovec *iov = i->iov; |
| 1805 | if (i->nr_segs == 1) |
| 1806 | return i->count; |
| 1807 | else |
| 1808 | return min(i->count, iov->iov_len - i->iov_offset); |
| 1809 | } |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 1810 | EXPORT_SYMBOL(iov_iter_single_seg_count); |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1811 | |
| 1812 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1813 | * Performs necessary checks before doing a write |
| 1814 | * |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 1815 | * Can adjust writing position or amount of bytes to write. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1816 | * Returns appropriate error code that caller should return or |
| 1817 | * zero in case that write should be allowed. |
| 1818 | */ |
| 1819 | inline int generic_write_checks(struct file *file, loff_t *pos, size_t *count, int isblk) |
| 1820 | { |
| 1821 | struct inode *inode = file->f_mapping->host; |
| 1822 | unsigned long limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; |
| 1823 | |
| 1824 | if (unlikely(*pos < 0)) |
| 1825 | return -EINVAL; |
| 1826 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1827 | if (!isblk) { |
| 1828 | /* FIXME: this is for backwards compatibility with 2.4 */ |
| 1829 | if (file->f_flags & O_APPEND) |
| 1830 | *pos = i_size_read(inode); |
| 1831 | |
| 1832 | if (limit != RLIM_INFINITY) { |
| 1833 | if (*pos >= limit) { |
| 1834 | send_sig(SIGXFSZ, current, 0); |
| 1835 | return -EFBIG; |
| 1836 | } |
| 1837 | if (*count > limit - (typeof(limit))*pos) { |
| 1838 | *count = limit - (typeof(limit))*pos; |
| 1839 | } |
| 1840 | } |
| 1841 | } |
| 1842 | |
| 1843 | /* |
| 1844 | * LFS rule |
| 1845 | */ |
| 1846 | if (unlikely(*pos + *count > MAX_NON_LFS && |
| 1847 | !(file->f_flags & O_LARGEFILE))) { |
| 1848 | if (*pos >= MAX_NON_LFS) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1849 | return -EFBIG; |
| 1850 | } |
| 1851 | if (*count > MAX_NON_LFS - (unsigned long)*pos) { |
| 1852 | *count = MAX_NON_LFS - (unsigned long)*pos; |
| 1853 | } |
| 1854 | } |
| 1855 | |
| 1856 | /* |
| 1857 | * Are we about to exceed the fs block limit ? |
| 1858 | * |
| 1859 | * If we have written data it becomes a short write. If we have |
| 1860 | * exceeded without writing data we send a signal and return EFBIG. |
| 1861 | * Linus frestrict idea will clean these up nicely.. |
| 1862 | */ |
| 1863 | if (likely(!isblk)) { |
| 1864 | if (unlikely(*pos >= inode->i_sb->s_maxbytes)) { |
| 1865 | if (*count || *pos > inode->i_sb->s_maxbytes) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1866 | return -EFBIG; |
| 1867 | } |
| 1868 | /* zero-length writes at ->s_maxbytes are OK */ |
| 1869 | } |
| 1870 | |
| 1871 | if (unlikely(*pos + *count > inode->i_sb->s_maxbytes)) |
| 1872 | *count = inode->i_sb->s_maxbytes - *pos; |
| 1873 | } else { |
David Howells | 9361401 | 2006-09-30 20:45:40 +0200 | [diff] [blame] | 1874 | #ifdef CONFIG_BLOCK |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1875 | loff_t isize; |
| 1876 | if (bdev_read_only(I_BDEV(inode))) |
| 1877 | return -EPERM; |
| 1878 | isize = i_size_read(inode); |
| 1879 | if (*pos >= isize) { |
| 1880 | if (*count || *pos > isize) |
| 1881 | return -ENOSPC; |
| 1882 | } |
| 1883 | |
| 1884 | if (*pos + *count > isize) |
| 1885 | *count = isize - *pos; |
David Howells | 9361401 | 2006-09-30 20:45:40 +0200 | [diff] [blame] | 1886 | #else |
| 1887 | return -EPERM; |
| 1888 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1889 | } |
| 1890 | return 0; |
| 1891 | } |
| 1892 | EXPORT_SYMBOL(generic_write_checks); |
| 1893 | |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1894 | int pagecache_write_begin(struct file *file, struct address_space *mapping, |
| 1895 | loff_t pos, unsigned len, unsigned flags, |
| 1896 | struct page **pagep, void **fsdata) |
| 1897 | { |
| 1898 | const struct address_space_operations *aops = mapping->a_ops; |
| 1899 | |
| 1900 | if (aops->write_begin) { |
| 1901 | return aops->write_begin(file, mapping, pos, len, flags, |
| 1902 | pagep, fsdata); |
| 1903 | } else { |
| 1904 | int ret; |
| 1905 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; |
| 1906 | unsigned offset = pos & (PAGE_CACHE_SIZE - 1); |
| 1907 | struct inode *inode = mapping->host; |
| 1908 | struct page *page; |
| 1909 | again: |
| 1910 | page = __grab_cache_page(mapping, index); |
| 1911 | *pagep = page; |
| 1912 | if (!page) |
| 1913 | return -ENOMEM; |
| 1914 | |
| 1915 | if (flags & AOP_FLAG_UNINTERRUPTIBLE && !PageUptodate(page)) { |
| 1916 | /* |
| 1917 | * There is no way to resolve a short write situation |
| 1918 | * for a !Uptodate page (except by double copying in |
| 1919 | * the caller done by generic_perform_write_2copy). |
| 1920 | * |
| 1921 | * Instead, we have to bring it uptodate here. |
| 1922 | */ |
| 1923 | ret = aops->readpage(file, page); |
| 1924 | page_cache_release(page); |
| 1925 | if (ret) { |
| 1926 | if (ret == AOP_TRUNCATED_PAGE) |
| 1927 | goto again; |
| 1928 | return ret; |
| 1929 | } |
| 1930 | goto again; |
| 1931 | } |
| 1932 | |
| 1933 | ret = aops->prepare_write(file, page, offset, offset+len); |
| 1934 | if (ret) { |
Nick Piggin | 5514476 | 2007-10-16 01:25:26 -0700 | [diff] [blame] | 1935 | unlock_page(page); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1936 | page_cache_release(page); |
| 1937 | if (pos + len > inode->i_size) |
| 1938 | vmtruncate(inode, inode->i_size); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1939 | } |
| 1940 | return ret; |
| 1941 | } |
| 1942 | } |
| 1943 | EXPORT_SYMBOL(pagecache_write_begin); |
| 1944 | |
| 1945 | int pagecache_write_end(struct file *file, struct address_space *mapping, |
| 1946 | loff_t pos, unsigned len, unsigned copied, |
| 1947 | struct page *page, void *fsdata) |
| 1948 | { |
| 1949 | const struct address_space_operations *aops = mapping->a_ops; |
| 1950 | int ret; |
| 1951 | |
| 1952 | if (aops->write_end) { |
| 1953 | mark_page_accessed(page); |
| 1954 | ret = aops->write_end(file, mapping, pos, len, copied, |
| 1955 | page, fsdata); |
| 1956 | } else { |
| 1957 | unsigned offset = pos & (PAGE_CACHE_SIZE - 1); |
| 1958 | struct inode *inode = mapping->host; |
| 1959 | |
| 1960 | flush_dcache_page(page); |
| 1961 | ret = aops->commit_write(file, page, offset, offset+len); |
| 1962 | unlock_page(page); |
| 1963 | mark_page_accessed(page); |
| 1964 | page_cache_release(page); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1965 | |
| 1966 | if (ret < 0) { |
| 1967 | if (pos + len > inode->i_size) |
| 1968 | vmtruncate(inode, inode->i_size); |
| 1969 | } else if (ret > 0) |
| 1970 | ret = min_t(size_t, copied, ret); |
| 1971 | else |
| 1972 | ret = copied; |
| 1973 | } |
| 1974 | |
| 1975 | return ret; |
| 1976 | } |
| 1977 | EXPORT_SYMBOL(pagecache_write_end); |
| 1978 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1979 | ssize_t |
| 1980 | generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov, |
| 1981 | unsigned long *nr_segs, loff_t pos, loff_t *ppos, |
| 1982 | size_t count, size_t ocount) |
| 1983 | { |
| 1984 | struct file *file = iocb->ki_filp; |
| 1985 | struct address_space *mapping = file->f_mapping; |
| 1986 | struct inode *inode = mapping->host; |
| 1987 | ssize_t written; |
| 1988 | |
| 1989 | if (count != ocount) |
| 1990 | *nr_segs = iov_shorten((struct iovec *)iov, *nr_segs, count); |
| 1991 | |
| 1992 | written = generic_file_direct_IO(WRITE, iocb, iov, pos, *nr_segs); |
| 1993 | if (written > 0) { |
| 1994 | loff_t end = pos + written; |
| 1995 | if (end > i_size_read(inode) && !S_ISBLK(inode->i_mode)) { |
| 1996 | i_size_write(inode, end); |
| 1997 | mark_inode_dirty(inode); |
| 1998 | } |
| 1999 | *ppos = end; |
| 2000 | } |
| 2001 | |
| 2002 | /* |
| 2003 | * Sync the fs metadata but not the minor inode changes and |
| 2004 | * of course not the data as we did direct DMA for the IO. |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2005 | * i_mutex is held, which protects generic_osync_inode() from |
Zach Brown | 8459d86 | 2006-12-10 02:21:05 -0800 | [diff] [blame] | 2006 | * livelocking. AIO O_DIRECT ops attempt to sync metadata here. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2007 | */ |
Zach Brown | 8459d86 | 2006-12-10 02:21:05 -0800 | [diff] [blame] | 2008 | if ((written >= 0 || written == -EIOCBQUEUED) && |
| 2009 | ((file->f_flags & O_SYNC) || IS_SYNC(inode))) { |
Hifumi Hisashi | 1e8a81c | 2005-06-25 14:54:32 -0700 | [diff] [blame] | 2010 | int err = generic_osync_inode(inode, mapping, OSYNC_METADATA); |
| 2011 | if (err < 0) |
| 2012 | written = err; |
| 2013 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2014 | return written; |
| 2015 | } |
| 2016 | EXPORT_SYMBOL(generic_file_direct_write); |
| 2017 | |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 2018 | /* |
| 2019 | * Find or create a page at the given pagecache position. Return the locked |
| 2020 | * page. This function is specifically for buffered writes. |
| 2021 | */ |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2022 | struct page *__grab_cache_page(struct address_space *mapping, pgoff_t index) |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 2023 | { |
| 2024 | int status; |
| 2025 | struct page *page; |
| 2026 | repeat: |
| 2027 | page = find_lock_page(mapping, index); |
| 2028 | if (likely(page)) |
| 2029 | return page; |
| 2030 | |
| 2031 | page = page_cache_alloc(mapping); |
| 2032 | if (!page) |
| 2033 | return NULL; |
| 2034 | status = add_to_page_cache_lru(page, mapping, index, GFP_KERNEL); |
| 2035 | if (unlikely(status)) { |
| 2036 | page_cache_release(page); |
| 2037 | if (status == -EEXIST) |
| 2038 | goto repeat; |
| 2039 | return NULL; |
| 2040 | } |
| 2041 | return page; |
| 2042 | } |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2043 | EXPORT_SYMBOL(__grab_cache_page); |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 2044 | |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2045 | static ssize_t generic_perform_write_2copy(struct file *file, |
| 2046 | struct iov_iter *i, loff_t pos) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2047 | { |
Andrew Morton | ae37461 | 2007-10-16 01:24:55 -0700 | [diff] [blame] | 2048 | struct address_space *mapping = file->f_mapping; |
Christoph Hellwig | f5e54d6 | 2006-06-28 04:26:44 -0700 | [diff] [blame] | 2049 | const struct address_space_operations *a_ops = mapping->a_ops; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2050 | struct inode *inode = mapping->host; |
| 2051 | long status = 0; |
| 2052 | ssize_t written = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2053 | |
| 2054 | do { |
Nick Piggin | 08291429 | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2055 | struct page *src_page; |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 2056 | struct page *page; |
Andrew Morton | ae37461 | 2007-10-16 01:24:55 -0700 | [diff] [blame] | 2057 | pgoff_t index; /* Pagecache index for current page */ |
| 2058 | unsigned long offset; /* Offset into pagecache page */ |
Nick Piggin | 08291429 | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2059 | unsigned long bytes; /* Bytes to write to page */ |
Andrew Morton | ae37461 | 2007-10-16 01:24:55 -0700 | [diff] [blame] | 2060 | size_t copied; /* Bytes copied from user */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2061 | |
Andrew Morton | ae37461 | 2007-10-16 01:24:55 -0700 | [diff] [blame] | 2062 | offset = (pos & (PAGE_CACHE_SIZE - 1)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2063 | index = pos >> PAGE_CACHE_SHIFT; |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2064 | bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset, |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2065 | iov_iter_count(i)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2066 | |
Nick Piggin | 08291429 | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2067 | /* |
| 2068 | * a non-NULL src_page indicates that we're doing the |
| 2069 | * copy via get_user_pages and kmap. |
| 2070 | */ |
| 2071 | src_page = NULL; |
Andrew Morton | ae37461 | 2007-10-16 01:24:55 -0700 | [diff] [blame] | 2072 | |
Nick Piggin | 41cb8ac | 2007-10-16 01:24:53 -0700 | [diff] [blame] | 2073 | /* |
| 2074 | * Bring in the user page that we will copy from _first_. |
| 2075 | * Otherwise there's a nasty deadlock on copying from the |
| 2076 | * same page as we're writing to, without it being marked |
| 2077 | * up-to-date. |
Nick Piggin | 08291429 | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2078 | * |
| 2079 | * Not only is this an optimisation, but it is also required |
| 2080 | * to check that the address is actually valid, when atomic |
| 2081 | * usercopies are used, below. |
Nick Piggin | 41cb8ac | 2007-10-16 01:24:53 -0700 | [diff] [blame] | 2082 | */ |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2083 | if (unlikely(iov_iter_fault_in_readable(i, bytes))) { |
Nick Piggin | 08291429 | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2084 | status = -EFAULT; |
| 2085 | break; |
| 2086 | } |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 2087 | |
| 2088 | page = __grab_cache_page(mapping, index); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2089 | if (!page) { |
| 2090 | status = -ENOMEM; |
| 2091 | break; |
| 2092 | } |
| 2093 | |
Nick Piggin | 08291429 | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2094 | /* |
| 2095 | * non-uptodate pages cannot cope with short copies, and we |
| 2096 | * cannot take a pagefault with the destination page locked. |
| 2097 | * So pin the source page to copy it. |
| 2098 | */ |
Nick Piggin | 674b892 | 2007-10-16 01:25:03 -0700 | [diff] [blame] | 2099 | if (!PageUptodate(page) && !segment_eq(get_fs(), KERNEL_DS)) { |
Nick Piggin | 08291429 | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2100 | unlock_page(page); |
| 2101 | |
| 2102 | src_page = alloc_page(GFP_KERNEL); |
| 2103 | if (!src_page) { |
| 2104 | page_cache_release(page); |
| 2105 | status = -ENOMEM; |
| 2106 | break; |
| 2107 | } |
| 2108 | |
| 2109 | /* |
| 2110 | * Cannot get_user_pages with a page locked for the |
| 2111 | * same reason as we can't take a page fault with a |
| 2112 | * page locked (as explained below). |
| 2113 | */ |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2114 | copied = iov_iter_copy_from_user(src_page, i, |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2115 | offset, bytes); |
Nick Piggin | 08291429 | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2116 | if (unlikely(copied == 0)) { |
| 2117 | status = -EFAULT; |
| 2118 | page_cache_release(page); |
| 2119 | page_cache_release(src_page); |
| 2120 | break; |
| 2121 | } |
| 2122 | bytes = copied; |
| 2123 | |
| 2124 | lock_page(page); |
| 2125 | /* |
| 2126 | * Can't handle the page going uptodate here, because |
| 2127 | * that means we would use non-atomic usercopies, which |
| 2128 | * zero out the tail of the page, which can cause |
| 2129 | * zeroes to become transiently visible. We could just |
| 2130 | * use a non-zeroing copy, but the APIs aren't too |
| 2131 | * consistent. |
| 2132 | */ |
| 2133 | if (unlikely(!page->mapping || PageUptodate(page))) { |
| 2134 | unlock_page(page); |
| 2135 | page_cache_release(page); |
| 2136 | page_cache_release(src_page); |
| 2137 | continue; |
| 2138 | } |
Nick Piggin | 08291429 | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2139 | } |
| 2140 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2141 | status = a_ops->prepare_write(file, page, offset, offset+bytes); |
Nick Piggin | 64649a5 | 2007-10-16 01:24:56 -0700 | [diff] [blame] | 2142 | if (unlikely(status)) |
| 2143 | goto fs_write_aop_error; |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 2144 | |
Nick Piggin | 08291429 | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2145 | if (!src_page) { |
| 2146 | /* |
| 2147 | * Must not enter the pagefault handler here, because |
| 2148 | * we hold the page lock, so we might recursively |
| 2149 | * deadlock on the same lock, or get an ABBA deadlock |
| 2150 | * against a different lock, or against the mmap_sem |
| 2151 | * (which nests outside the page lock). So increment |
| 2152 | * preempt count, and use _atomic usercopies. |
| 2153 | * |
| 2154 | * The page is uptodate so we are OK to encounter a |
| 2155 | * short copy: if unmodified parts of the page are |
| 2156 | * marked dirty and written out to disk, it doesn't |
| 2157 | * really matter. |
| 2158 | */ |
| 2159 | pagefault_disable(); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2160 | copied = iov_iter_copy_from_user_atomic(page, i, |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2161 | offset, bytes); |
Nick Piggin | 08291429 | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2162 | pagefault_enable(); |
| 2163 | } else { |
| 2164 | void *src, *dst; |
| 2165 | src = kmap_atomic(src_page, KM_USER0); |
| 2166 | dst = kmap_atomic(page, KM_USER1); |
| 2167 | memcpy(dst + offset, src + offset, bytes); |
| 2168 | kunmap_atomic(dst, KM_USER1); |
| 2169 | kunmap_atomic(src, KM_USER0); |
| 2170 | copied = bytes; |
| 2171 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2172 | flush_dcache_page(page); |
Nick Piggin | 4a9e5ef | 2007-10-16 01:24:58 -0700 | [diff] [blame] | 2173 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2174 | status = a_ops->commit_write(file, page, offset, offset+bytes); |
Nick Piggin | 5514476 | 2007-10-16 01:25:26 -0700 | [diff] [blame] | 2175 | if (unlikely(status < 0)) |
Nick Piggin | 64649a5 | 2007-10-16 01:24:56 -0700 | [diff] [blame] | 2176 | goto fs_write_aop_error; |
Nick Piggin | 64649a5 | 2007-10-16 01:24:56 -0700 | [diff] [blame] | 2177 | if (unlikely(status > 0)) /* filesystem did partial write */ |
Nick Piggin | 08291429 | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2178 | copied = min_t(size_t, copied, status); |
| 2179 | |
| 2180 | unlock_page(page); |
| 2181 | mark_page_accessed(page); |
| 2182 | page_cache_release(page); |
| 2183 | if (src_page) |
| 2184 | page_cache_release(src_page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2185 | |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2186 | iov_iter_advance(i, copied); |
Nick Piggin | 4a9e5ef | 2007-10-16 01:24:58 -0700 | [diff] [blame] | 2187 | pos += copied; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2188 | written += copied; |
Nick Piggin | 4a9e5ef | 2007-10-16 01:24:58 -0700 | [diff] [blame] | 2189 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2190 | balance_dirty_pages_ratelimited(mapping); |
| 2191 | cond_resched(); |
Nick Piggin | 64649a5 | 2007-10-16 01:24:56 -0700 | [diff] [blame] | 2192 | continue; |
| 2193 | |
| 2194 | fs_write_aop_error: |
Nick Piggin | 5514476 | 2007-10-16 01:25:26 -0700 | [diff] [blame] | 2195 | unlock_page(page); |
Nick Piggin | 64649a5 | 2007-10-16 01:24:56 -0700 | [diff] [blame] | 2196 | page_cache_release(page); |
Nick Piggin | 08291429 | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2197 | if (src_page) |
| 2198 | page_cache_release(src_page); |
Nick Piggin | 64649a5 | 2007-10-16 01:24:56 -0700 | [diff] [blame] | 2199 | |
| 2200 | /* |
| 2201 | * prepare_write() may have instantiated a few blocks |
| 2202 | * outside i_size. Trim these off again. Don't need |
| 2203 | * i_size_read because we hold i_mutex. |
| 2204 | */ |
| 2205 | if (pos + bytes > inode->i_size) |
| 2206 | vmtruncate(inode, inode->i_size); |
Nick Piggin | 5514476 | 2007-10-16 01:25:26 -0700 | [diff] [blame] | 2207 | break; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2208 | } while (iov_iter_count(i)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2209 | |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2210 | return written ? written : status; |
| 2211 | } |
| 2212 | |
| 2213 | static ssize_t generic_perform_write(struct file *file, |
| 2214 | struct iov_iter *i, loff_t pos) |
| 2215 | { |
| 2216 | struct address_space *mapping = file->f_mapping; |
| 2217 | const struct address_space_operations *a_ops = mapping->a_ops; |
| 2218 | long status = 0; |
| 2219 | ssize_t written = 0; |
Nick Piggin | 674b892 | 2007-10-16 01:25:03 -0700 | [diff] [blame] | 2220 | unsigned int flags = 0; |
| 2221 | |
| 2222 | /* |
| 2223 | * Copies from kernel address space cannot fail (NFSD is a big user). |
| 2224 | */ |
| 2225 | if (segment_eq(get_fs(), KERNEL_DS)) |
| 2226 | flags |= AOP_FLAG_UNINTERRUPTIBLE; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2227 | |
| 2228 | do { |
| 2229 | struct page *page; |
| 2230 | pgoff_t index; /* Pagecache index for current page */ |
| 2231 | unsigned long offset; /* Offset into pagecache page */ |
| 2232 | unsigned long bytes; /* Bytes to write to page */ |
| 2233 | size_t copied; /* Bytes copied from user */ |
| 2234 | void *fsdata; |
| 2235 | |
| 2236 | offset = (pos & (PAGE_CACHE_SIZE - 1)); |
| 2237 | index = pos >> PAGE_CACHE_SHIFT; |
| 2238 | bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset, |
| 2239 | iov_iter_count(i)); |
| 2240 | |
| 2241 | again: |
| 2242 | |
| 2243 | /* |
| 2244 | * Bring in the user page that we will copy from _first_. |
| 2245 | * Otherwise there's a nasty deadlock on copying from the |
| 2246 | * same page as we're writing to, without it being marked |
| 2247 | * up-to-date. |
| 2248 | * |
| 2249 | * Not only is this an optimisation, but it is also required |
| 2250 | * to check that the address is actually valid, when atomic |
| 2251 | * usercopies are used, below. |
| 2252 | */ |
| 2253 | if (unlikely(iov_iter_fault_in_readable(i, bytes))) { |
| 2254 | status = -EFAULT; |
| 2255 | break; |
| 2256 | } |
| 2257 | |
Nick Piggin | 674b892 | 2007-10-16 01:25:03 -0700 | [diff] [blame] | 2258 | status = a_ops->write_begin(file, mapping, pos, bytes, flags, |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2259 | &page, &fsdata); |
| 2260 | if (unlikely(status)) |
| 2261 | break; |
| 2262 | |
| 2263 | pagefault_disable(); |
| 2264 | copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes); |
| 2265 | pagefault_enable(); |
| 2266 | flush_dcache_page(page); |
| 2267 | |
| 2268 | status = a_ops->write_end(file, mapping, pos, bytes, copied, |
| 2269 | page, fsdata); |
| 2270 | if (unlikely(status < 0)) |
| 2271 | break; |
| 2272 | copied = status; |
| 2273 | |
| 2274 | cond_resched(); |
| 2275 | |
Nick Piggin | 124d3b7 | 2008-02-02 15:01:17 +0100 | [diff] [blame] | 2276 | iov_iter_advance(i, copied); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2277 | if (unlikely(copied == 0)) { |
| 2278 | /* |
| 2279 | * If we were unable to copy any data at all, we must |
| 2280 | * fall back to a single segment length write. |
| 2281 | * |
| 2282 | * If we didn't fallback here, we could livelock |
| 2283 | * because not all segments in the iov can be copied at |
| 2284 | * once without a pagefault. |
| 2285 | */ |
| 2286 | bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset, |
| 2287 | iov_iter_single_seg_count(i)); |
| 2288 | goto again; |
| 2289 | } |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2290 | pos += copied; |
| 2291 | written += copied; |
| 2292 | |
| 2293 | balance_dirty_pages_ratelimited(mapping); |
| 2294 | |
| 2295 | } while (iov_iter_count(i)); |
| 2296 | |
| 2297 | return written ? written : status; |
| 2298 | } |
| 2299 | |
| 2300 | ssize_t |
| 2301 | generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov, |
| 2302 | unsigned long nr_segs, loff_t pos, loff_t *ppos, |
| 2303 | size_t count, ssize_t written) |
| 2304 | { |
| 2305 | struct file *file = iocb->ki_filp; |
| 2306 | struct address_space *mapping = file->f_mapping; |
| 2307 | const struct address_space_operations *a_ops = mapping->a_ops; |
| 2308 | struct inode *inode = mapping->host; |
| 2309 | ssize_t status; |
| 2310 | struct iov_iter i; |
| 2311 | |
| 2312 | iov_iter_init(&i, iov, nr_segs, count, written); |
| 2313 | if (a_ops->write_begin) |
| 2314 | status = generic_perform_write(file, &i, pos); |
| 2315 | else |
| 2316 | status = generic_perform_write_2copy(file, &i, pos); |
| 2317 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2318 | if (likely(status >= 0)) { |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2319 | written += status; |
| 2320 | *ppos = pos + status; |
| 2321 | |
| 2322 | /* |
| 2323 | * For now, when the user asks for O_SYNC, we'll actually give |
| 2324 | * O_DSYNC |
| 2325 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2326 | if (unlikely((file->f_flags & O_SYNC) || IS_SYNC(inode))) { |
| 2327 | if (!a_ops->writepage || !is_sync_kiocb(iocb)) |
| 2328 | status = generic_osync_inode(inode, mapping, |
| 2329 | OSYNC_METADATA|OSYNC_DATA); |
| 2330 | } |
| 2331 | } |
| 2332 | |
| 2333 | /* |
| 2334 | * If we get here for O_DIRECT writes then we must have fallen through |
| 2335 | * to buffered writes (block instantiation inside i_size). So we sync |
| 2336 | * the file data here, to try to honour O_DIRECT expectations. |
| 2337 | */ |
| 2338 | if (unlikely(file->f_flags & O_DIRECT) && written) |
| 2339 | status = filemap_write_and_wait(mapping); |
| 2340 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2341 | return written ? written : status; |
| 2342 | } |
| 2343 | EXPORT_SYMBOL(generic_file_buffered_write); |
| 2344 | |
Adrian Bunk | 5ce7852 | 2005-09-10 00:26:28 -0700 | [diff] [blame] | 2345 | static ssize_t |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2346 | __generic_file_aio_write_nolock(struct kiocb *iocb, const struct iovec *iov, |
| 2347 | unsigned long nr_segs, loff_t *ppos) |
| 2348 | { |
| 2349 | struct file *file = iocb->ki_filp; |
Jeff Moyer | fb5527e | 2006-10-19 23:28:13 -0700 | [diff] [blame] | 2350 | struct address_space * mapping = file->f_mapping; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2351 | size_t ocount; /* original count */ |
| 2352 | size_t count; /* after file limit checks */ |
| 2353 | struct inode *inode = mapping->host; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2354 | loff_t pos; |
| 2355 | ssize_t written; |
| 2356 | ssize_t err; |
| 2357 | |
| 2358 | ocount = 0; |
Dmitriy Monakhov | 0ceb331 | 2007-05-08 00:23:02 -0700 | [diff] [blame] | 2359 | err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ); |
| 2360 | if (err) |
| 2361 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2362 | |
| 2363 | count = ocount; |
| 2364 | pos = *ppos; |
| 2365 | |
| 2366 | vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE); |
| 2367 | |
| 2368 | /* We can write back this queue in page reclaim */ |
| 2369 | current->backing_dev_info = mapping->backing_dev_info; |
| 2370 | written = 0; |
| 2371 | |
| 2372 | err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode)); |
| 2373 | if (err) |
| 2374 | goto out; |
| 2375 | |
| 2376 | if (count == 0) |
| 2377 | goto out; |
| 2378 | |
Josef "Jeff" Sipek | d3ac7f8 | 2006-12-08 02:36:44 -0800 | [diff] [blame] | 2379 | err = remove_suid(file->f_path.dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2380 | if (err) |
| 2381 | goto out; |
| 2382 | |
Christoph Hellwig | 870f481 | 2006-01-09 20:52:01 -0800 | [diff] [blame] | 2383 | file_update_time(file); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2384 | |
| 2385 | /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */ |
| 2386 | if (unlikely(file->f_flags & O_DIRECT)) { |
Jeff Moyer | fb5527e | 2006-10-19 23:28:13 -0700 | [diff] [blame] | 2387 | loff_t endbyte; |
| 2388 | ssize_t written_buffered; |
| 2389 | |
| 2390 | written = generic_file_direct_write(iocb, iov, &nr_segs, pos, |
| 2391 | ppos, count, ocount); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2392 | if (written < 0 || written == count) |
| 2393 | goto out; |
| 2394 | /* |
| 2395 | * direct-io write to a hole: fall through to buffered I/O |
| 2396 | * for completing the rest of the request. |
| 2397 | */ |
| 2398 | pos += written; |
| 2399 | count -= written; |
Jeff Moyer | fb5527e | 2006-10-19 23:28:13 -0700 | [diff] [blame] | 2400 | written_buffered = generic_file_buffered_write(iocb, iov, |
| 2401 | nr_segs, pos, ppos, count, |
| 2402 | written); |
| 2403 | /* |
| 2404 | * If generic_file_buffered_write() retuned a synchronous error |
| 2405 | * then we want to return the number of bytes which were |
| 2406 | * direct-written, or the error code if that was zero. Note |
| 2407 | * that this differs from normal direct-io semantics, which |
| 2408 | * will return -EFOO even if some bytes were written. |
| 2409 | */ |
| 2410 | if (written_buffered < 0) { |
| 2411 | err = written_buffered; |
| 2412 | goto out; |
| 2413 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2414 | |
Jeff Moyer | fb5527e | 2006-10-19 23:28:13 -0700 | [diff] [blame] | 2415 | /* |
| 2416 | * We need to ensure that the page cache pages are written to |
| 2417 | * disk and invalidated to preserve the expected O_DIRECT |
| 2418 | * semantics. |
| 2419 | */ |
| 2420 | endbyte = pos + written_buffered - written - 1; |
Mark Fasheh | ef51c97 | 2007-05-08 00:27:10 -0700 | [diff] [blame] | 2421 | err = do_sync_mapping_range(file->f_mapping, pos, endbyte, |
| 2422 | SYNC_FILE_RANGE_WAIT_BEFORE| |
| 2423 | SYNC_FILE_RANGE_WRITE| |
| 2424 | SYNC_FILE_RANGE_WAIT_AFTER); |
Jeff Moyer | fb5527e | 2006-10-19 23:28:13 -0700 | [diff] [blame] | 2425 | if (err == 0) { |
| 2426 | written = written_buffered; |
| 2427 | invalidate_mapping_pages(mapping, |
| 2428 | pos >> PAGE_CACHE_SHIFT, |
| 2429 | endbyte >> PAGE_CACHE_SHIFT); |
| 2430 | } else { |
| 2431 | /* |
| 2432 | * We don't know how much we wrote, so just return |
| 2433 | * the number of bytes which were direct-written |
| 2434 | */ |
| 2435 | } |
| 2436 | } else { |
| 2437 | written = generic_file_buffered_write(iocb, iov, nr_segs, |
| 2438 | pos, ppos, count, written); |
| 2439 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2440 | out: |
| 2441 | current->backing_dev_info = NULL; |
| 2442 | return written ? written : err; |
| 2443 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2444 | |
Badari Pulavarty | 027445c | 2006-09-30 23:28:46 -0700 | [diff] [blame] | 2445 | ssize_t generic_file_aio_write_nolock(struct kiocb *iocb, |
| 2446 | const struct iovec *iov, unsigned long nr_segs, loff_t pos) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2447 | { |
| 2448 | struct file *file = iocb->ki_filp; |
| 2449 | struct address_space *mapping = file->f_mapping; |
| 2450 | struct inode *inode = mapping->host; |
| 2451 | ssize_t ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2452 | |
Badari Pulavarty | 027445c | 2006-09-30 23:28:46 -0700 | [diff] [blame] | 2453 | BUG_ON(iocb->ki_pos != pos); |
| 2454 | |
| 2455 | ret = __generic_file_aio_write_nolock(iocb, iov, nr_segs, |
| 2456 | &iocb->ki_pos); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2457 | |
| 2458 | if (ret > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) { |
Badari Pulavarty | 027445c | 2006-09-30 23:28:46 -0700 | [diff] [blame] | 2459 | ssize_t err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2460 | |
| 2461 | err = sync_page_range_nolock(inode, mapping, pos, ret); |
| 2462 | if (err < 0) |
| 2463 | ret = err; |
| 2464 | } |
| 2465 | return ret; |
| 2466 | } |
Badari Pulavarty | 027445c | 2006-09-30 23:28:46 -0700 | [diff] [blame] | 2467 | EXPORT_SYMBOL(generic_file_aio_write_nolock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2468 | |
Badari Pulavarty | 027445c | 2006-09-30 23:28:46 -0700 | [diff] [blame] | 2469 | ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov, |
| 2470 | unsigned long nr_segs, loff_t pos) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2471 | { |
| 2472 | struct file *file = iocb->ki_filp; |
| 2473 | struct address_space *mapping = file->f_mapping; |
| 2474 | struct inode *inode = mapping->host; |
| 2475 | ssize_t ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2476 | |
| 2477 | BUG_ON(iocb->ki_pos != pos); |
| 2478 | |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2479 | mutex_lock(&inode->i_mutex); |
Badari Pulavarty | 027445c | 2006-09-30 23:28:46 -0700 | [diff] [blame] | 2480 | ret = __generic_file_aio_write_nolock(iocb, iov, nr_segs, |
| 2481 | &iocb->ki_pos); |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2482 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2483 | |
| 2484 | if (ret > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) { |
| 2485 | ssize_t err; |
| 2486 | |
| 2487 | err = sync_page_range(inode, mapping, pos, ret); |
| 2488 | if (err < 0) |
| 2489 | ret = err; |
| 2490 | } |
| 2491 | return ret; |
| 2492 | } |
| 2493 | EXPORT_SYMBOL(generic_file_aio_write); |
| 2494 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2495 | /* |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2496 | * Called under i_mutex for writes to S_ISREG files. Returns -EIO if something |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2497 | * went wrong during pagecache shootdown. |
| 2498 | */ |
Adrian Bunk | 5ce7852 | 2005-09-10 00:26:28 -0700 | [diff] [blame] | 2499 | static ssize_t |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2500 | generic_file_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, |
| 2501 | loff_t offset, unsigned long nr_segs) |
| 2502 | { |
| 2503 | struct file *file = iocb->ki_filp; |
| 2504 | struct address_space *mapping = file->f_mapping; |
| 2505 | ssize_t retval; |
Zach Brown | 65b8291 | 2007-03-16 13:38:11 -0800 | [diff] [blame] | 2506 | size_t write_len; |
| 2507 | pgoff_t end = 0; /* silence gcc */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2508 | |
| 2509 | /* |
| 2510 | * If it's a write, unmap all mmappings of the file up-front. This |
| 2511 | * will cause any pte dirty bits to be propagated into the pageframes |
| 2512 | * for the subsequent filemap_write_and_wait(). |
| 2513 | */ |
| 2514 | if (rw == WRITE) { |
| 2515 | write_len = iov_length(iov, nr_segs); |
Zach Brown | 65b8291 | 2007-03-16 13:38:11 -0800 | [diff] [blame] | 2516 | end = (offset + write_len - 1) >> PAGE_CACHE_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2517 | if (mapping_mapped(mapping)) |
| 2518 | unmap_mapping_range(mapping, offset, write_len, 0); |
| 2519 | } |
| 2520 | |
| 2521 | retval = filemap_write_and_wait(mapping); |
Zach Brown | 65b8291 | 2007-03-16 13:38:11 -0800 | [diff] [blame] | 2522 | if (retval) |
| 2523 | goto out; |
| 2524 | |
| 2525 | /* |
| 2526 | * After a write we want buffered reads to be sure to go to disk to get |
| 2527 | * the new data. We invalidate clean cached page from the region we're |
| 2528 | * about to write. We do this *before* the write so that we can return |
| 2529 | * -EIO without clobbering -EIOCBQUEUED from ->direct_IO(). |
| 2530 | */ |
| 2531 | if (rw == WRITE && mapping->nrpages) { |
| 2532 | retval = invalidate_inode_pages2_range(mapping, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2533 | offset >> PAGE_CACHE_SHIFT, end); |
Zach Brown | 65b8291 | 2007-03-16 13:38:11 -0800 | [diff] [blame] | 2534 | if (retval) |
| 2535 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2536 | } |
Zach Brown | 65b8291 | 2007-03-16 13:38:11 -0800 | [diff] [blame] | 2537 | |
| 2538 | retval = mapping->a_ops->direct_IO(rw, iocb, iov, offset, nr_segs); |
Zach Brown | 65b8291 | 2007-03-16 13:38:11 -0800 | [diff] [blame] | 2539 | |
| 2540 | /* |
| 2541 | * Finally, try again to invalidate clean pages which might have been |
Zach Brown | bdb76ef | 2007-10-30 11:45:46 -0700 | [diff] [blame] | 2542 | * cached by non-direct readahead, or faulted in by get_user_pages() |
| 2543 | * if the source of the write was an mmap'ed region of the file |
| 2544 | * we're writing. Either one is a pretty crazy thing to do, |
| 2545 | * so we don't support it 100%. If this invalidation |
| 2546 | * fails, tough, the write still worked... |
Zach Brown | 65b8291 | 2007-03-16 13:38:11 -0800 | [diff] [blame] | 2547 | */ |
| 2548 | if (rw == WRITE && mapping->nrpages) { |
Zach Brown | bdb76ef | 2007-10-30 11:45:46 -0700 | [diff] [blame] | 2549 | invalidate_inode_pages2_range(mapping, offset >> PAGE_CACHE_SHIFT, end); |
Zach Brown | 65b8291 | 2007-03-16 13:38:11 -0800 | [diff] [blame] | 2550 | } |
| 2551 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2552 | return retval; |
| 2553 | } |
David Howells | cf9a2ae | 2006-08-29 19:05:54 +0100 | [diff] [blame] | 2554 | |
| 2555 | /** |
| 2556 | * try_to_release_page() - release old fs-specific metadata on a page |
| 2557 | * |
| 2558 | * @page: the page which the kernel is trying to free |
| 2559 | * @gfp_mask: memory allocation flags (and I/O mode) |
| 2560 | * |
| 2561 | * The address_space is to try to release any data against the page |
| 2562 | * (presumably at page->private). If the release was successful, return `1'. |
| 2563 | * Otherwise return zero. |
| 2564 | * |
| 2565 | * The @gfp_mask argument specifies whether I/O may be performed to release |
| 2566 | * this page (__GFP_IO), and whether the call may block (__GFP_WAIT). |
| 2567 | * |
| 2568 | * NOTE: @gfp_mask may go away, and this function may become non-blocking. |
| 2569 | */ |
| 2570 | int try_to_release_page(struct page *page, gfp_t gfp_mask) |
| 2571 | { |
| 2572 | struct address_space * const mapping = page->mapping; |
| 2573 | |
| 2574 | BUG_ON(!PageLocked(page)); |
| 2575 | if (PageWriteback(page)) |
| 2576 | return 0; |
| 2577 | |
| 2578 | if (mapping && mapping->a_ops->releasepage) |
| 2579 | return mapping->a_ops->releasepage(page, gfp_mask); |
| 2580 | return try_to_free_buffers(page); |
| 2581 | } |
| 2582 | |
| 2583 | EXPORT_SYMBOL(try_to_release_page); |