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> |
| 31 | #include <linux/security.h> |
| 32 | #include <linux/syscalls.h> |
Paul Jackson | 44110fe | 2006-03-24 03:16:04 -0800 | [diff] [blame] | 33 | #include <linux/cpuset.h> |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 34 | #include <linux/hardirq.h> /* for BUG_ON(!in_atomic()) only */ |
Balbir Singh | 8a9f3cc | 2008-02-07 00:13:53 -0800 | [diff] [blame] | 35 | #include <linux/memcontrol.h> |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 36 | #include <linux/mm_inline.h> /* for page_is_file_cache() */ |
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 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | /* |
| 48 | * Shared mappings implemented 30.11.1994. It's not fully working yet, |
| 49 | * though. |
| 50 | * |
| 51 | * Shared mappings now work. 15.8.1995 Bruno. |
| 52 | * |
| 53 | * finished 'unifying' the page and buffer cache and SMP-threaded the |
| 54 | * page-cache, 21.05.1999, Ingo Molnar <mingo@redhat.com> |
| 55 | * |
| 56 | * SMP-threaded pagemap-LRU 1999, Andrea Arcangeli <andrea@suse.de> |
| 57 | */ |
| 58 | |
| 59 | /* |
| 60 | * Lock ordering: |
| 61 | * |
| 62 | * ->i_mmap_lock (vmtruncate) |
| 63 | * ->private_lock (__free_pte->__set_page_dirty_buffers) |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 64 | * ->swap_lock (exclusive_swap_page, others) |
| 65 | * ->mapping->tree_lock |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 66 | * |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 67 | * ->i_mutex |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 68 | * ->i_mmap_lock (truncate->unmap_mapping_range) |
| 69 | * |
| 70 | * ->mmap_sem |
| 71 | * ->i_mmap_lock |
Hugh Dickins | b8072f0 | 2005-10-29 18:16:41 -0700 | [diff] [blame] | 72 | * ->page_table_lock or pte_lock (various, mainly in memory.c) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 73 | * ->mapping->tree_lock (arch-dependent flush_dcache_mmap_lock) |
| 74 | * |
| 75 | * ->mmap_sem |
| 76 | * ->lock_page (access_process_vm) |
| 77 | * |
Nick Piggin | 82591e6 | 2006-10-19 23:29:10 -0700 | [diff] [blame] | 78 | * ->i_mutex (generic_file_buffered_write) |
| 79 | * ->mmap_sem (fault_in_pages_readable->do_page_fault) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 80 | * |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 81 | * ->i_mutex |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | * ->i_alloc_sem (various) |
| 83 | * |
| 84 | * ->inode_lock |
| 85 | * ->sb_lock (fs/fs-writeback.c) |
| 86 | * ->mapping->tree_lock (__sync_single_inode) |
| 87 | * |
| 88 | * ->i_mmap_lock |
| 89 | * ->anon_vma.lock (vma_adjust) |
| 90 | * |
| 91 | * ->anon_vma.lock |
Hugh Dickins | b8072f0 | 2005-10-29 18:16:41 -0700 | [diff] [blame] | 92 | * ->page_table_lock or pte_lock (anon_vma_prepare and various) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 93 | * |
Hugh Dickins | b8072f0 | 2005-10-29 18:16:41 -0700 | [diff] [blame] | 94 | * ->page_table_lock or pte_lock |
Hugh Dickins | 5d337b9 | 2005-09-03 15:54:41 -0700 | [diff] [blame] | 95 | * ->swap_lock (try_to_unmap_one) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 96 | * ->private_lock (try_to_unmap_one) |
| 97 | * ->tree_lock (try_to_unmap_one) |
| 98 | * ->zone.lru_lock (follow_page->mark_page_accessed) |
Nick Piggin | 053837f | 2006-01-18 17:42:27 -0800 | [diff] [blame] | 99 | * ->zone.lru_lock (check_pte_range->isolate_lru_page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 100 | * ->private_lock (page_remove_rmap->set_page_dirty) |
| 101 | * ->tree_lock (page_remove_rmap->set_page_dirty) |
| 102 | * ->inode_lock (page_remove_rmap->set_page_dirty) |
| 103 | * ->inode_lock (zap_pte_range->set_page_dirty) |
| 104 | * ->private_lock (zap_pte_range->__set_page_dirty_buffers) |
| 105 | * |
| 106 | * ->task->proc_lock |
| 107 | * ->dcache_lock (proc_pid_lookup) |
| 108 | */ |
| 109 | |
| 110 | /* |
| 111 | * Remove a page from the page cache and free it. Caller has to make |
| 112 | * sure the page is locked and that nobody else uses it - or that usage |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 113 | * is safe. The caller must hold the mapping's tree_lock. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 114 | */ |
| 115 | void __remove_from_page_cache(struct page *page) |
| 116 | { |
| 117 | struct address_space *mapping = page->mapping; |
| 118 | |
| 119 | radix_tree_delete(&mapping->page_tree, page->index); |
| 120 | page->mapping = NULL; |
| 121 | mapping->nrpages--; |
Christoph Lameter | 347ce43 | 2006-06-30 01:55:35 -0700 | [diff] [blame] | 122 | __dec_zone_page_state(page, NR_FILE_PAGES); |
Nick Piggin | 4542681 | 2007-07-15 23:38:12 -0700 | [diff] [blame] | 123 | BUG_ON(page_mapped(page)); |
Linus Torvalds | 3a69279 | 2007-12-19 14:05:13 -0800 | [diff] [blame] | 124 | |
| 125 | /* |
| 126 | * Some filesystems seem to re-dirty the page even after |
| 127 | * the VM has canceled the dirty bit (eg ext3 journaling). |
| 128 | * |
| 129 | * Fix it up by doing a final dirty accounting check after |
| 130 | * having removed the page entirely. |
| 131 | */ |
| 132 | if (PageDirty(page) && mapping_cap_account_dirty(mapping)) { |
| 133 | dec_zone_page_state(page, NR_FILE_DIRTY); |
| 134 | dec_bdi_stat(mapping->backing_dev_info, BDI_RECLAIMABLE); |
| 135 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 136 | } |
| 137 | |
| 138 | void remove_from_page_cache(struct page *page) |
| 139 | { |
| 140 | struct address_space *mapping = page->mapping; |
| 141 | |
Matt Mackall | cd7619d | 2005-05-01 08:59:01 -0700 | [diff] [blame] | 142 | BUG_ON(!PageLocked(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 143 | |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 144 | spin_lock_irq(&mapping->tree_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 145 | __remove_from_page_cache(page); |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 146 | spin_unlock_irq(&mapping->tree_lock); |
Daisuke Nishimura | e767e05 | 2009-05-28 14:34:28 -0700 | [diff] [blame] | 147 | mem_cgroup_uncharge_cache_page(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 148 | } |
| 149 | |
| 150 | static int sync_page(void *word) |
| 151 | { |
| 152 | struct address_space *mapping; |
| 153 | struct page *page; |
| 154 | |
Andi Kleen | 07808b7 | 2005-11-05 17:25:53 +0100 | [diff] [blame] | 155 | page = container_of((unsigned long *)word, struct page, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 156 | |
| 157 | /* |
William Lee Irwin III | dd1d5af | 2005-05-01 08:58:38 -0700 | [diff] [blame] | 158 | * page_mapping() is being called without PG_locked held. |
| 159 | * Some knowledge of the state and use of the page is used to |
| 160 | * reduce the requirements down to a memory barrier. |
| 161 | * The danger here is of a stale page_mapping() return value |
| 162 | * indicating a struct address_space different from the one it's |
| 163 | * associated with when it is associated with one. |
| 164 | * After smp_mb(), it's either the correct page_mapping() for |
| 165 | * the page, or an old page_mapping() and the page's own |
| 166 | * page_mapping() has gone NULL. |
| 167 | * The ->sync_page() address_space operation must tolerate |
| 168 | * page_mapping() going NULL. By an amazing coincidence, |
| 169 | * this comes about because none of the users of the page |
| 170 | * in the ->sync_page() methods make essential use of the |
| 171 | * page_mapping(), merely passing the page down to the backing |
| 172 | * device's unplug functions when it's non-NULL, which in turn |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 173 | * 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] | 174 | * of interest. When page_mapping() does go NULL, the entire |
| 175 | * call stack gracefully ignores the page and returns. |
| 176 | * -- wli |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | */ |
| 178 | smp_mb(); |
| 179 | mapping = page_mapping(page); |
| 180 | if (mapping && mapping->a_ops && mapping->a_ops->sync_page) |
| 181 | mapping->a_ops->sync_page(page); |
| 182 | io_schedule(); |
| 183 | return 0; |
| 184 | } |
| 185 | |
Matthew Wilcox | 2687a35 | 2007-12-06 11:18:49 -0500 | [diff] [blame] | 186 | static int sync_page_killable(void *word) |
| 187 | { |
| 188 | sync_page(word); |
| 189 | return fatal_signal_pending(current) ? -EINTR : 0; |
| 190 | } |
| 191 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 192 | /** |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 193 | * __filemap_fdatawrite_range - start writeback on mapping dirty pages in range |
Martin Waitz | 67be2dd | 2005-05-01 08:59:26 -0700 | [diff] [blame] | 194 | * @mapping: address space structure to write |
| 195 | * @start: offset in bytes where the range starts |
Andrew Morton | 469eb4d | 2006-03-24 03:17:45 -0800 | [diff] [blame] | 196 | * @end: offset in bytes where the range ends (inclusive) |
Martin Waitz | 67be2dd | 2005-05-01 08:59:26 -0700 | [diff] [blame] | 197 | * @sync_mode: enable synchronous operation |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 198 | * |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 199 | * Start writeback against all of a mapping's dirty pages that lie |
| 200 | * within the byte offsets <start, end> inclusive. |
| 201 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | * 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] | 203 | * opposed to a regular memory cleansing writeback. The difference between |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 204 | * these two operations is that if a dirty page/buffer is encountered, it must |
| 205 | * be waited upon, and not just skipped over. |
| 206 | */ |
Andrew Morton | ebcf28e | 2006-03-24 03:18:04 -0800 | [diff] [blame] | 207 | int __filemap_fdatawrite_range(struct address_space *mapping, loff_t start, |
| 208 | loff_t end, int sync_mode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 209 | { |
| 210 | int ret; |
| 211 | struct writeback_control wbc = { |
| 212 | .sync_mode = sync_mode, |
Nick Piggin | 05fe478 | 2009-01-06 14:39:08 -0800 | [diff] [blame] | 213 | .nr_to_write = LONG_MAX, |
OGAWA Hirofumi | 111ebb6 | 2006-06-23 02:03:26 -0700 | [diff] [blame] | 214 | .range_start = start, |
| 215 | .range_end = end, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 216 | }; |
| 217 | |
| 218 | if (!mapping_cap_writeback_dirty(mapping)) |
| 219 | return 0; |
| 220 | |
| 221 | ret = do_writepages(mapping, &wbc); |
| 222 | return ret; |
| 223 | } |
| 224 | |
| 225 | static inline int __filemap_fdatawrite(struct address_space *mapping, |
| 226 | int sync_mode) |
| 227 | { |
OGAWA Hirofumi | 111ebb6 | 2006-06-23 02:03:26 -0700 | [diff] [blame] | 228 | return __filemap_fdatawrite_range(mapping, 0, LLONG_MAX, sync_mode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 229 | } |
| 230 | |
| 231 | int filemap_fdatawrite(struct address_space *mapping) |
| 232 | { |
| 233 | return __filemap_fdatawrite(mapping, WB_SYNC_ALL); |
| 234 | } |
| 235 | EXPORT_SYMBOL(filemap_fdatawrite); |
| 236 | |
Jan Kara | f4c0a0f | 2008-07-11 19:27:31 -0400 | [diff] [blame] | 237 | int filemap_fdatawrite_range(struct address_space *mapping, loff_t start, |
Andrew Morton | ebcf28e | 2006-03-24 03:18:04 -0800 | [diff] [blame] | 238 | loff_t end) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 239 | { |
| 240 | return __filemap_fdatawrite_range(mapping, start, end, WB_SYNC_ALL); |
| 241 | } |
Jan Kara | f4c0a0f | 2008-07-11 19:27:31 -0400 | [diff] [blame] | 242 | EXPORT_SYMBOL(filemap_fdatawrite_range); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 243 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 244 | /** |
| 245 | * filemap_flush - mostly a non-blocking flush |
| 246 | * @mapping: target address_space |
| 247 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 248 | * This is a mostly non-blocking flush. Not suitable for data-integrity |
| 249 | * purposes - I/O may not be started against all dirty pages. |
| 250 | */ |
| 251 | int filemap_flush(struct address_space *mapping) |
| 252 | { |
| 253 | return __filemap_fdatawrite(mapping, WB_SYNC_NONE); |
| 254 | } |
| 255 | EXPORT_SYMBOL(filemap_flush); |
| 256 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 257 | /** |
| 258 | * wait_on_page_writeback_range - wait for writeback to complete |
| 259 | * @mapping: target address_space |
| 260 | * @start: beginning page index |
| 261 | * @end: ending page index |
| 262 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 263 | * Wait for writeback to complete against pages indexed by start->end |
| 264 | * inclusive |
| 265 | */ |
Andrew Morton | ebcf28e | 2006-03-24 03:18:04 -0800 | [diff] [blame] | 266 | int wait_on_page_writeback_range(struct address_space *mapping, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 267 | pgoff_t start, pgoff_t end) |
| 268 | { |
| 269 | struct pagevec pvec; |
| 270 | int nr_pages; |
| 271 | int ret = 0; |
| 272 | pgoff_t index; |
| 273 | |
| 274 | if (end < start) |
| 275 | return 0; |
| 276 | |
| 277 | pagevec_init(&pvec, 0); |
| 278 | index = start; |
| 279 | while ((index <= end) && |
| 280 | (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, |
| 281 | PAGECACHE_TAG_WRITEBACK, |
| 282 | min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1)) != 0) { |
| 283 | unsigned i; |
| 284 | |
| 285 | for (i = 0; i < nr_pages; i++) { |
| 286 | struct page *page = pvec.pages[i]; |
| 287 | |
| 288 | /* until radix tree lookup accepts end_index */ |
| 289 | if (page->index > end) |
| 290 | continue; |
| 291 | |
| 292 | wait_on_page_writeback(page); |
| 293 | if (PageError(page)) |
| 294 | ret = -EIO; |
| 295 | } |
| 296 | pagevec_release(&pvec); |
| 297 | cond_resched(); |
| 298 | } |
| 299 | |
| 300 | /* Check for outstanding write errors */ |
| 301 | if (test_and_clear_bit(AS_ENOSPC, &mapping->flags)) |
| 302 | ret = -ENOSPC; |
| 303 | if (test_and_clear_bit(AS_EIO, &mapping->flags)) |
| 304 | ret = -EIO; |
| 305 | |
| 306 | return ret; |
| 307 | } |
| 308 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 309 | /** |
Jan Kara | d3bccb6 | 2009-08-17 19:30:27 +0200 | [diff] [blame^] | 310 | * filemap_fdatawait_range - wait for all under-writeback pages to complete in a given range |
| 311 | * @mapping: address space structure to wait for |
| 312 | * @start: offset in bytes where the range starts |
| 313 | * @end: offset in bytes where the range ends (inclusive) |
| 314 | * |
| 315 | * Walk the list of under-writeback pages of the given address space |
| 316 | * in the given range and wait for all of them. |
| 317 | * |
| 318 | * This is just a simple wrapper so that callers don't have to convert offsets |
| 319 | * to page indexes themselves |
| 320 | */ |
| 321 | int filemap_fdatawait_range(struct address_space *mapping, loff_t start, |
| 322 | loff_t end) |
| 323 | { |
| 324 | return wait_on_page_writeback_range(mapping, start >> PAGE_CACHE_SHIFT, |
| 325 | end >> PAGE_CACHE_SHIFT); |
| 326 | } |
| 327 | EXPORT_SYMBOL(filemap_fdatawait_range); |
| 328 | |
| 329 | /** |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 330 | * sync_page_range - write and wait on all pages in the passed range |
| 331 | * @inode: target inode |
| 332 | * @mapping: target address_space |
| 333 | * @pos: beginning offset in pages to write |
| 334 | * @count: number of bytes to write |
| 335 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 336 | * Write and wait upon all the pages in the passed range. This is a "data |
| 337 | * integrity" operation. It waits upon in-flight writeout before starting and |
| 338 | * waiting upon new writeout. If there was an IO error, return it. |
| 339 | * |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 340 | * 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] | 341 | * it is otherwise livelockable. |
| 342 | */ |
| 343 | int sync_page_range(struct inode *inode, struct address_space *mapping, |
OGAWA Hirofumi | 268fc16 | 2006-01-08 01:02:12 -0800 | [diff] [blame] | 344 | loff_t pos, loff_t count) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 345 | { |
| 346 | pgoff_t start = pos >> PAGE_CACHE_SHIFT; |
| 347 | pgoff_t end = (pos + count - 1) >> PAGE_CACHE_SHIFT; |
| 348 | int ret; |
| 349 | |
| 350 | if (!mapping_cap_writeback_dirty(mapping) || !count) |
| 351 | return 0; |
| 352 | ret = filemap_fdatawrite_range(mapping, pos, pos + count - 1); |
| 353 | if (ret == 0) { |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 354 | mutex_lock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 355 | ret = generic_osync_inode(inode, mapping, OSYNC_METADATA); |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 356 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 357 | } |
| 358 | if (ret == 0) |
| 359 | ret = wait_on_page_writeback_range(mapping, start, end); |
| 360 | return ret; |
| 361 | } |
| 362 | EXPORT_SYMBOL(sync_page_range); |
| 363 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 364 | /** |
Randy Dunlap | 7682486 | 2008-03-19 17:00:40 -0700 | [diff] [blame] | 365 | * sync_page_range_nolock - write & wait on all pages in the passed range without locking |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 366 | * @inode: target inode |
| 367 | * @mapping: target address_space |
| 368 | * @pos: beginning offset in pages to write |
| 369 | * @count: number of bytes to write |
| 370 | * |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame] | 371 | * 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] | 372 | * as it forces O_SYNC writers to different parts of the same file |
| 373 | * to be serialised right until io completion. |
| 374 | */ |
OGAWA Hirofumi | 268fc16 | 2006-01-08 01:02:12 -0800 | [diff] [blame] | 375 | int sync_page_range_nolock(struct inode *inode, struct address_space *mapping, |
| 376 | loff_t pos, loff_t count) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 377 | { |
| 378 | pgoff_t start = pos >> PAGE_CACHE_SHIFT; |
| 379 | pgoff_t end = (pos + count - 1) >> PAGE_CACHE_SHIFT; |
| 380 | int ret; |
| 381 | |
| 382 | if (!mapping_cap_writeback_dirty(mapping) || !count) |
| 383 | return 0; |
| 384 | ret = filemap_fdatawrite_range(mapping, pos, pos + count - 1); |
| 385 | if (ret == 0) |
| 386 | ret = generic_osync_inode(inode, mapping, OSYNC_METADATA); |
| 387 | if (ret == 0) |
| 388 | ret = wait_on_page_writeback_range(mapping, start, end); |
| 389 | return ret; |
| 390 | } |
OGAWA Hirofumi | 268fc16 | 2006-01-08 01:02:12 -0800 | [diff] [blame] | 391 | EXPORT_SYMBOL(sync_page_range_nolock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 392 | |
| 393 | /** |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 394 | * filemap_fdatawait - wait for all under-writeback pages to complete |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 395 | * @mapping: address space structure to wait for |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 396 | * |
| 397 | * Walk the list of under-writeback pages of the given address space |
| 398 | * and wait for all of them. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 399 | */ |
| 400 | int filemap_fdatawait(struct address_space *mapping) |
| 401 | { |
| 402 | loff_t i_size = i_size_read(mapping->host); |
| 403 | |
| 404 | if (i_size == 0) |
| 405 | return 0; |
| 406 | |
| 407 | return wait_on_page_writeback_range(mapping, 0, |
| 408 | (i_size - 1) >> PAGE_CACHE_SHIFT); |
| 409 | } |
| 410 | EXPORT_SYMBOL(filemap_fdatawait); |
| 411 | |
| 412 | int filemap_write_and_wait(struct address_space *mapping) |
| 413 | { |
OGAWA Hirofumi | 28fd129 | 2006-01-08 01:02:14 -0800 | [diff] [blame] | 414 | int err = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 415 | |
| 416 | if (mapping->nrpages) { |
OGAWA Hirofumi | 28fd129 | 2006-01-08 01:02:14 -0800 | [diff] [blame] | 417 | err = filemap_fdatawrite(mapping); |
| 418 | /* |
| 419 | * Even if the above returned error, the pages may be |
| 420 | * written partially (e.g. -ENOSPC), so we wait for it. |
| 421 | * But the -EIO is special case, it may indicate the worst |
| 422 | * thing (e.g. bug) happened, so we avoid waiting for it. |
| 423 | */ |
| 424 | if (err != -EIO) { |
| 425 | int err2 = filemap_fdatawait(mapping); |
| 426 | if (!err) |
| 427 | err = err2; |
| 428 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 429 | } |
OGAWA Hirofumi | 28fd129 | 2006-01-08 01:02:14 -0800 | [diff] [blame] | 430 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 431 | } |
OGAWA Hirofumi | 28fd129 | 2006-01-08 01:02:14 -0800 | [diff] [blame] | 432 | EXPORT_SYMBOL(filemap_write_and_wait); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 433 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 434 | /** |
| 435 | * filemap_write_and_wait_range - write out & wait on a file range |
| 436 | * @mapping: the address_space for the pages |
| 437 | * @lstart: offset in bytes where the range starts |
| 438 | * @lend: offset in bytes where the range ends (inclusive) |
| 439 | * |
Andrew Morton | 469eb4d | 2006-03-24 03:17:45 -0800 | [diff] [blame] | 440 | * Write out and wait upon file offsets lstart->lend, inclusive. |
| 441 | * |
| 442 | * Note that `lend' is inclusive (describes the last byte to be written) so |
| 443 | * that this function can be used to write to the very end-of-file (end = -1). |
| 444 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 445 | int filemap_write_and_wait_range(struct address_space *mapping, |
| 446 | loff_t lstart, loff_t lend) |
| 447 | { |
OGAWA Hirofumi | 28fd129 | 2006-01-08 01:02:14 -0800 | [diff] [blame] | 448 | int err = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 449 | |
| 450 | if (mapping->nrpages) { |
OGAWA Hirofumi | 28fd129 | 2006-01-08 01:02:14 -0800 | [diff] [blame] | 451 | err = __filemap_fdatawrite_range(mapping, lstart, lend, |
| 452 | WB_SYNC_ALL); |
| 453 | /* See comment of filemap_write_and_wait() */ |
| 454 | if (err != -EIO) { |
| 455 | int err2 = wait_on_page_writeback_range(mapping, |
| 456 | lstart >> PAGE_CACHE_SHIFT, |
| 457 | lend >> PAGE_CACHE_SHIFT); |
| 458 | if (!err) |
| 459 | err = err2; |
| 460 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 461 | } |
OGAWA Hirofumi | 28fd129 | 2006-01-08 01:02:14 -0800 | [diff] [blame] | 462 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 463 | } |
Chris Mason | f699558 | 2009-04-15 13:22:37 -0400 | [diff] [blame] | 464 | EXPORT_SYMBOL(filemap_write_and_wait_range); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 465 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 466 | /** |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 467 | * add_to_page_cache_locked - add a locked page to the pagecache |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 468 | * @page: page to add |
| 469 | * @mapping: the page's address_space |
| 470 | * @offset: page index |
| 471 | * @gfp_mask: page allocation mode |
| 472 | * |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 473 | * This function is used to add a page to the pagecache. It must be locked. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 474 | * This function does not add the page to the LRU. The caller must do that. |
| 475 | */ |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 476 | int add_to_page_cache_locked(struct page *page, struct address_space *mapping, |
Al Viro | 6daa0e2 | 2005-10-21 03:18:50 -0400 | [diff] [blame] | 477 | pgoff_t offset, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 478 | { |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 479 | int error; |
| 480 | |
| 481 | VM_BUG_ON(!PageLocked(page)); |
| 482 | |
| 483 | error = mem_cgroup_cache_charge(page, current->mm, |
KAMEZAWA Hiroyuki | 2c26fdd | 2009-01-07 18:08:10 -0800 | [diff] [blame] | 484 | gfp_mask & GFP_RECLAIM_MASK); |
Balbir Singh | 35c754d | 2008-02-07 00:14:05 -0800 | [diff] [blame] | 485 | if (error) |
| 486 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 487 | |
Balbir Singh | 35c754d | 2008-02-07 00:14:05 -0800 | [diff] [blame] | 488 | error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 489 | if (error == 0) { |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 490 | page_cache_get(page); |
| 491 | page->mapping = mapping; |
| 492 | page->index = offset; |
| 493 | |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 494 | spin_lock_irq(&mapping->tree_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 495 | error = radix_tree_insert(&mapping->page_tree, offset, page); |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 496 | if (likely(!error)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 497 | mapping->nrpages++; |
Christoph Lameter | 347ce43 | 2006-06-30 01:55:35 -0700 | [diff] [blame] | 498 | __inc_zone_page_state(page, NR_FILE_PAGES); |
Daisuke Nishimura | e767e05 | 2009-05-28 14:34:28 -0700 | [diff] [blame] | 499 | spin_unlock_irq(&mapping->tree_lock); |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 500 | } else { |
| 501 | page->mapping = NULL; |
Daisuke Nishimura | e767e05 | 2009-05-28 14:34:28 -0700 | [diff] [blame] | 502 | spin_unlock_irq(&mapping->tree_lock); |
KAMEZAWA Hiroyuki | 69029cd | 2008-07-25 01:47:14 -0700 | [diff] [blame] | 503 | mem_cgroup_uncharge_cache_page(page); |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 504 | page_cache_release(page); |
| 505 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 506 | radix_tree_preload_end(); |
Balbir Singh | 35c754d | 2008-02-07 00:14:05 -0800 | [diff] [blame] | 507 | } else |
KAMEZAWA Hiroyuki | 69029cd | 2008-07-25 01:47:14 -0700 | [diff] [blame] | 508 | mem_cgroup_uncharge_cache_page(page); |
Balbir Singh | 8a9f3cc | 2008-02-07 00:13:53 -0800 | [diff] [blame] | 509 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 510 | return error; |
| 511 | } |
Nick Piggin | e286781 | 2008-07-25 19:45:30 -0700 | [diff] [blame] | 512 | EXPORT_SYMBOL(add_to_page_cache_locked); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 513 | |
| 514 | 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] | 515 | pgoff_t offset, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 516 | { |
Rik van Riel | 4f98a2f | 2008-10-18 20:26:32 -0700 | [diff] [blame] | 517 | int ret; |
| 518 | |
| 519 | /* |
| 520 | * Splice_read and readahead add shmem/tmpfs pages into the page cache |
| 521 | * before shmem_readpage has a chance to mark them as SwapBacked: they |
| 522 | * need to go on the active_anon lru below, and mem_cgroup_cache_charge |
| 523 | * (called in add_to_page_cache) needs to know where they're going too. |
| 524 | */ |
| 525 | if (mapping_cap_swap_backed(mapping)) |
| 526 | SetPageSwapBacked(page); |
| 527 | |
| 528 | ret = add_to_page_cache(page, mapping, offset, gfp_mask); |
| 529 | if (ret == 0) { |
| 530 | if (page_is_file_cache(page)) |
| 531 | lru_cache_add_file(page); |
| 532 | else |
| 533 | lru_cache_add_active_anon(page); |
| 534 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 535 | return ret; |
| 536 | } |
Evgeniy Polyakov | 18bc0bb | 2009-02-09 17:02:42 +0300 | [diff] [blame] | 537 | EXPORT_SYMBOL_GPL(add_to_page_cache_lru); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 538 | |
Paul Jackson | 44110fe | 2006-03-24 03:16:04 -0800 | [diff] [blame] | 539 | #ifdef CONFIG_NUMA |
Nick Piggin | 2ae8814 | 2006-10-28 10:38:23 -0700 | [diff] [blame] | 540 | struct page *__page_cache_alloc(gfp_t gfp) |
Paul Jackson | 44110fe | 2006-03-24 03:16:04 -0800 | [diff] [blame] | 541 | { |
| 542 | if (cpuset_do_page_mem_spread()) { |
| 543 | int n = cpuset_mem_spread_node(); |
Mel Gorman | 6484eb3 | 2009-06-16 15:31:54 -0700 | [diff] [blame] | 544 | return alloc_pages_exact_node(n, gfp, 0); |
Paul Jackson | 44110fe | 2006-03-24 03:16:04 -0800 | [diff] [blame] | 545 | } |
Nick Piggin | 2ae8814 | 2006-10-28 10:38:23 -0700 | [diff] [blame] | 546 | return alloc_pages(gfp, 0); |
Paul Jackson | 44110fe | 2006-03-24 03:16:04 -0800 | [diff] [blame] | 547 | } |
Nick Piggin | 2ae8814 | 2006-10-28 10:38:23 -0700 | [diff] [blame] | 548 | EXPORT_SYMBOL(__page_cache_alloc); |
Paul Jackson | 44110fe | 2006-03-24 03:16:04 -0800 | [diff] [blame] | 549 | #endif |
| 550 | |
Nick Piggin | db37648 | 2006-09-25 23:31:24 -0700 | [diff] [blame] | 551 | static int __sleep_on_page_lock(void *word) |
| 552 | { |
| 553 | io_schedule(); |
| 554 | return 0; |
| 555 | } |
| 556 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 557 | /* |
| 558 | * In order to wait for pages to become available there must be |
| 559 | * waitqueues associated with pages. By using a hash table of |
| 560 | * waitqueues where the bucket discipline is to maintain all |
| 561 | * waiters on the same queue and wake all when any of the pages |
| 562 | * become available, and for the woken contexts to check to be |
| 563 | * sure the appropriate page became available, this saves space |
| 564 | * at a cost of "thundering herd" phenomena during rare hash |
| 565 | * collisions. |
| 566 | */ |
| 567 | static wait_queue_head_t *page_waitqueue(struct page *page) |
| 568 | { |
| 569 | const struct zone *zone = page_zone(page); |
| 570 | |
| 571 | return &zone->wait_table[hash_ptr(page, zone->wait_table_bits)]; |
| 572 | } |
| 573 | |
| 574 | static inline void wake_up_page(struct page *page, int bit) |
| 575 | { |
| 576 | __wake_up_bit(page_waitqueue(page), &page->flags, bit); |
| 577 | } |
| 578 | |
Harvey Harrison | 920c7a5 | 2008-02-04 22:29:26 -0800 | [diff] [blame] | 579 | void wait_on_page_bit(struct page *page, int bit_nr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 580 | { |
| 581 | DEFINE_WAIT_BIT(wait, &page->flags, bit_nr); |
| 582 | |
| 583 | if (test_bit(bit_nr, &page->flags)) |
| 584 | __wait_on_bit(page_waitqueue(page), &wait, sync_page, |
| 585 | TASK_UNINTERRUPTIBLE); |
| 586 | } |
| 587 | EXPORT_SYMBOL(wait_on_page_bit); |
| 588 | |
| 589 | /** |
David Howells | 385e1ca | 2009-04-03 16:42:39 +0100 | [diff] [blame] | 590 | * add_page_wait_queue - Add an arbitrary waiter to a page's wait queue |
Randy Dunlap | 697f619 | 2009-04-13 14:39:54 -0700 | [diff] [blame] | 591 | * @page: Page defining the wait queue of interest |
| 592 | * @waiter: Waiter to add to the queue |
David Howells | 385e1ca | 2009-04-03 16:42:39 +0100 | [diff] [blame] | 593 | * |
| 594 | * Add an arbitrary @waiter to the wait queue for the nominated @page. |
| 595 | */ |
| 596 | void add_page_wait_queue(struct page *page, wait_queue_t *waiter) |
| 597 | { |
| 598 | wait_queue_head_t *q = page_waitqueue(page); |
| 599 | unsigned long flags; |
| 600 | |
| 601 | spin_lock_irqsave(&q->lock, flags); |
| 602 | __add_wait_queue(q, waiter); |
| 603 | spin_unlock_irqrestore(&q->lock, flags); |
| 604 | } |
| 605 | EXPORT_SYMBOL_GPL(add_page_wait_queue); |
| 606 | |
| 607 | /** |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 608 | * unlock_page - unlock a locked page |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 609 | * @page: the page |
| 610 | * |
| 611 | * Unlocks the page and wakes up sleepers in ___wait_on_page_locked(). |
| 612 | * Also wakes sleepers in wait_on_page_writeback() because the wakeup |
| 613 | * mechananism between PageLocked pages and PageWriteback pages is shared. |
| 614 | * But that's OK - sleepers in wait_on_page_writeback() just go back to sleep. |
| 615 | * |
Nick Piggin | 8413ac9 | 2008-10-18 20:26:59 -0700 | [diff] [blame] | 616 | * The mb is necessary to enforce ordering between the clear_bit and the read |
| 617 | * of the waitqueue (to avoid SMP races with a parallel wait_on_page_locked()). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 618 | */ |
Harvey Harrison | 920c7a5 | 2008-02-04 22:29:26 -0800 | [diff] [blame] | 619 | void unlock_page(struct page *page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 620 | { |
Nick Piggin | 8413ac9 | 2008-10-18 20:26:59 -0700 | [diff] [blame] | 621 | VM_BUG_ON(!PageLocked(page)); |
| 622 | clear_bit_unlock(PG_locked, &page->flags); |
| 623 | smp_mb__after_clear_bit(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 624 | wake_up_page(page, PG_locked); |
| 625 | } |
| 626 | EXPORT_SYMBOL(unlock_page); |
| 627 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 628 | /** |
| 629 | * end_page_writeback - end writeback against a page |
| 630 | * @page: the page |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 631 | */ |
| 632 | void end_page_writeback(struct page *page) |
| 633 | { |
Miklos Szeredi | ac6aadb | 2008-04-28 02:12:38 -0700 | [diff] [blame] | 634 | if (TestClearPageReclaim(page)) |
| 635 | rotate_reclaimable_page(page); |
| 636 | |
| 637 | if (!test_clear_page_writeback(page)) |
| 638 | BUG(); |
| 639 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 640 | smp_mb__after_clear_bit(); |
| 641 | wake_up_page(page, PG_writeback); |
| 642 | } |
| 643 | EXPORT_SYMBOL(end_page_writeback); |
| 644 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 645 | /** |
| 646 | * __lock_page - get a lock on the page, assuming we need to sleep to get it |
| 647 | * @page: the page to lock |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 648 | * |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 649 | * Ugly. Running sync_page() in state TASK_UNINTERRUPTIBLE is scary. If some |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 650 | * random driver's requestfn sets TASK_RUNNING, we could busywait. However |
| 651 | * chances are that on the second loop, the block layer's plug list is empty, |
| 652 | * so sync_page() will then return in state TASK_UNINTERRUPTIBLE. |
| 653 | */ |
Harvey Harrison | 920c7a5 | 2008-02-04 22:29:26 -0800 | [diff] [blame] | 654 | void __lock_page(struct page *page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 655 | { |
| 656 | DEFINE_WAIT_BIT(wait, &page->flags, PG_locked); |
| 657 | |
| 658 | __wait_on_bit_lock(page_waitqueue(page), &wait, sync_page, |
| 659 | TASK_UNINTERRUPTIBLE); |
| 660 | } |
| 661 | EXPORT_SYMBOL(__lock_page); |
| 662 | |
Harvey Harrison | b5606c2 | 2008-02-13 15:03:16 -0800 | [diff] [blame] | 663 | int __lock_page_killable(struct page *page) |
Matthew Wilcox | 2687a35 | 2007-12-06 11:18:49 -0500 | [diff] [blame] | 664 | { |
| 665 | DEFINE_WAIT_BIT(wait, &page->flags, PG_locked); |
| 666 | |
| 667 | return __wait_on_bit_lock(page_waitqueue(page), &wait, |
| 668 | sync_page_killable, TASK_KILLABLE); |
| 669 | } |
Evgeniy Polyakov | 18bc0bb | 2009-02-09 17:02:42 +0300 | [diff] [blame] | 670 | EXPORT_SYMBOL_GPL(__lock_page_killable); |
Matthew Wilcox | 2687a35 | 2007-12-06 11:18:49 -0500 | [diff] [blame] | 671 | |
Randy Dunlap | 7682486 | 2008-03-19 17:00:40 -0700 | [diff] [blame] | 672 | /** |
| 673 | * __lock_page_nosync - get a lock on the page, without calling sync_page() |
| 674 | * @page: the page to lock |
| 675 | * |
Nick Piggin | db37648 | 2006-09-25 23:31:24 -0700 | [diff] [blame] | 676 | * Variant of lock_page that does not require the caller to hold a reference |
| 677 | * on the page's mapping. |
| 678 | */ |
Harvey Harrison | 920c7a5 | 2008-02-04 22:29:26 -0800 | [diff] [blame] | 679 | void __lock_page_nosync(struct page *page) |
Nick Piggin | db37648 | 2006-09-25 23:31:24 -0700 | [diff] [blame] | 680 | { |
| 681 | DEFINE_WAIT_BIT(wait, &page->flags, PG_locked); |
| 682 | __wait_on_bit_lock(page_waitqueue(page), &wait, __sleep_on_page_lock, |
| 683 | TASK_UNINTERRUPTIBLE); |
| 684 | } |
| 685 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 686 | /** |
| 687 | * find_get_page - find and get a page reference |
| 688 | * @mapping: the address_space to search |
| 689 | * @offset: the page index |
| 690 | * |
Nick Piggin | da6052f | 2006-09-25 23:31:35 -0700 | [diff] [blame] | 691 | * Is there a pagecache struct page at the given (mapping, offset) tuple? |
| 692 | * If yes, increment its refcount and return it; if no, return NULL. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 693 | */ |
Nick Piggin | a60637c | 2008-07-25 19:45:31 -0700 | [diff] [blame] | 694 | struct page *find_get_page(struct address_space *mapping, pgoff_t offset) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 695 | { |
Nick Piggin | a60637c | 2008-07-25 19:45:31 -0700 | [diff] [blame] | 696 | void **pagep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 697 | struct page *page; |
| 698 | |
Nick Piggin | a60637c | 2008-07-25 19:45:31 -0700 | [diff] [blame] | 699 | rcu_read_lock(); |
| 700 | repeat: |
| 701 | page = NULL; |
| 702 | pagep = radix_tree_lookup_slot(&mapping->page_tree, offset); |
| 703 | if (pagep) { |
| 704 | page = radix_tree_deref_slot(pagep); |
| 705 | if (unlikely(!page || page == RADIX_TREE_RETRY)) |
| 706 | goto repeat; |
| 707 | |
| 708 | if (!page_cache_get_speculative(page)) |
| 709 | goto repeat; |
| 710 | |
| 711 | /* |
| 712 | * Has the page moved? |
| 713 | * This is part of the lockless pagecache protocol. See |
| 714 | * include/linux/pagemap.h for details. |
| 715 | */ |
| 716 | if (unlikely(page != *pagep)) { |
| 717 | page_cache_release(page); |
| 718 | goto repeat; |
| 719 | } |
| 720 | } |
| 721 | rcu_read_unlock(); |
| 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_get_page); |
| 726 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 727 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 728 | * find_lock_page - locate, pin and lock a pagecache page |
Martin Waitz | 67be2dd | 2005-05-01 08:59:26 -0700 | [diff] [blame] | 729 | * @mapping: the address_space to search |
| 730 | * @offset: the page index |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 731 | * |
| 732 | * Locates the desired pagecache page, locks it, increments its reference |
| 733 | * count and returns its address. |
| 734 | * |
| 735 | * Returns zero if the page was not present. find_lock_page() may sleep. |
| 736 | */ |
Nick Piggin | a60637c | 2008-07-25 19:45:31 -0700 | [diff] [blame] | 737 | struct page *find_lock_page(struct address_space *mapping, pgoff_t offset) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 738 | { |
| 739 | struct page *page; |
| 740 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 741 | repeat: |
Nick Piggin | a60637c | 2008-07-25 19:45:31 -0700 | [diff] [blame] | 742 | page = find_get_page(mapping, offset); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 743 | if (page) { |
Nick Piggin | a60637c | 2008-07-25 19:45:31 -0700 | [diff] [blame] | 744 | lock_page(page); |
| 745 | /* Has the page been truncated? */ |
| 746 | if (unlikely(page->mapping != mapping)) { |
| 747 | unlock_page(page); |
| 748 | page_cache_release(page); |
| 749 | goto repeat; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 750 | } |
Nick Piggin | a60637c | 2008-07-25 19:45:31 -0700 | [diff] [blame] | 751 | VM_BUG_ON(page->index != offset); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 752 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 753 | return page; |
| 754 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 755 | EXPORT_SYMBOL(find_lock_page); |
| 756 | |
| 757 | /** |
| 758 | * find_or_create_page - locate or add a pagecache page |
Martin Waitz | 67be2dd | 2005-05-01 08:59:26 -0700 | [diff] [blame] | 759 | * @mapping: the page's address_space |
| 760 | * @index: the page's index into the mapping |
| 761 | * @gfp_mask: page allocation mode |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 762 | * |
| 763 | * Locates a page in the pagecache. If the page is not present, a new page |
| 764 | * is allocated using @gfp_mask and is added to the pagecache and to the VM's |
| 765 | * LRU list. The returned page is locked and has its reference count |
| 766 | * incremented. |
| 767 | * |
| 768 | * find_or_create_page() may sleep, even if @gfp_flags specifies an atomic |
| 769 | * allocation! |
| 770 | * |
| 771 | * find_or_create_page() returns the desired page's address, or zero on |
| 772 | * memory exhaustion. |
| 773 | */ |
| 774 | struct page *find_or_create_page(struct address_space *mapping, |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 775 | pgoff_t index, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 776 | { |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 777 | struct page *page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 778 | int err; |
| 779 | repeat: |
| 780 | page = find_lock_page(mapping, index); |
| 781 | if (!page) { |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 782 | page = __page_cache_alloc(gfp_mask); |
| 783 | if (!page) |
| 784 | return NULL; |
Nick Piggin | 67d58ac | 2009-01-06 14:40:28 -0800 | [diff] [blame] | 785 | /* |
| 786 | * We want a regular kernel memory (not highmem or DMA etc) |
| 787 | * allocation for the radix tree nodes, but we need to honour |
| 788 | * the context-specific requirements the caller has asked for. |
| 789 | * GFP_RECLAIM_MASK collects those requirements. |
| 790 | */ |
| 791 | err = add_to_page_cache_lru(page, mapping, index, |
| 792 | (gfp_mask & GFP_RECLAIM_MASK)); |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 793 | if (unlikely(err)) { |
| 794 | page_cache_release(page); |
| 795 | page = NULL; |
| 796 | if (err == -EEXIST) |
| 797 | goto repeat; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 798 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 799 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 800 | return page; |
| 801 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 802 | EXPORT_SYMBOL(find_or_create_page); |
| 803 | |
| 804 | /** |
| 805 | * find_get_pages - gang pagecache lookup |
| 806 | * @mapping: The address_space to search |
| 807 | * @start: The starting page index |
| 808 | * @nr_pages: The maximum number of pages |
| 809 | * @pages: Where the resulting pages are placed |
| 810 | * |
| 811 | * find_get_pages() will search for and return a group of up to |
| 812 | * @nr_pages pages in the mapping. The pages are placed at @pages. |
| 813 | * find_get_pages() takes a reference against the returned pages. |
| 814 | * |
| 815 | * The search returns a group of mapping-contiguous pages with ascending |
| 816 | * indexes. There may be holes in the indices due to not-present pages. |
| 817 | * |
| 818 | * find_get_pages() returns the number of pages which were found. |
| 819 | */ |
| 820 | unsigned find_get_pages(struct address_space *mapping, pgoff_t start, |
| 821 | unsigned int nr_pages, struct page **pages) |
| 822 | { |
| 823 | unsigned int i; |
| 824 | unsigned int ret; |
Nick Piggin | a60637c | 2008-07-25 19:45:31 -0700 | [diff] [blame] | 825 | unsigned int nr_found; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 826 | |
Nick Piggin | a60637c | 2008-07-25 19:45:31 -0700 | [diff] [blame] | 827 | rcu_read_lock(); |
| 828 | restart: |
| 829 | nr_found = radix_tree_gang_lookup_slot(&mapping->page_tree, |
| 830 | (void ***)pages, start, nr_pages); |
| 831 | ret = 0; |
| 832 | for (i = 0; i < nr_found; i++) { |
| 833 | struct page *page; |
| 834 | repeat: |
| 835 | page = radix_tree_deref_slot((void **)pages[i]); |
| 836 | if (unlikely(!page)) |
| 837 | continue; |
| 838 | /* |
| 839 | * this can only trigger if nr_found == 1, making livelock |
| 840 | * a non issue. |
| 841 | */ |
| 842 | if (unlikely(page == RADIX_TREE_RETRY)) |
| 843 | goto restart; |
| 844 | |
| 845 | if (!page_cache_get_speculative(page)) |
| 846 | goto repeat; |
| 847 | |
| 848 | /* Has the page moved? */ |
| 849 | if (unlikely(page != *((void **)pages[i]))) { |
| 850 | page_cache_release(page); |
| 851 | goto repeat; |
| 852 | } |
| 853 | |
| 854 | pages[ret] = page; |
| 855 | ret++; |
| 856 | } |
| 857 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 858 | return ret; |
| 859 | } |
| 860 | |
Jens Axboe | ebf4350 | 2006-04-27 08:46:01 +0200 | [diff] [blame] | 861 | /** |
| 862 | * find_get_pages_contig - gang contiguous pagecache lookup |
| 863 | * @mapping: The address_space to search |
| 864 | * @index: The starting page index |
| 865 | * @nr_pages: The maximum number of pages |
| 866 | * @pages: Where the resulting pages are placed |
| 867 | * |
| 868 | * find_get_pages_contig() works exactly like find_get_pages(), except |
| 869 | * that the returned number of pages are guaranteed to be contiguous. |
| 870 | * |
| 871 | * find_get_pages_contig() returns the number of pages which were found. |
| 872 | */ |
| 873 | unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index, |
| 874 | unsigned int nr_pages, struct page **pages) |
| 875 | { |
| 876 | unsigned int i; |
| 877 | unsigned int ret; |
Nick Piggin | a60637c | 2008-07-25 19:45:31 -0700 | [diff] [blame] | 878 | unsigned int nr_found; |
Jens Axboe | ebf4350 | 2006-04-27 08:46:01 +0200 | [diff] [blame] | 879 | |
Nick Piggin | a60637c | 2008-07-25 19:45:31 -0700 | [diff] [blame] | 880 | rcu_read_lock(); |
| 881 | restart: |
| 882 | nr_found = radix_tree_gang_lookup_slot(&mapping->page_tree, |
| 883 | (void ***)pages, index, nr_pages); |
| 884 | ret = 0; |
| 885 | for (i = 0; i < nr_found; i++) { |
| 886 | struct page *page; |
| 887 | repeat: |
| 888 | page = radix_tree_deref_slot((void **)pages[i]); |
| 889 | if (unlikely(!page)) |
| 890 | continue; |
| 891 | /* |
| 892 | * this can only trigger if nr_found == 1, making livelock |
| 893 | * a non issue. |
| 894 | */ |
| 895 | if (unlikely(page == RADIX_TREE_RETRY)) |
| 896 | goto restart; |
| 897 | |
| 898 | if (page->mapping == NULL || page->index != index) |
Jens Axboe | ebf4350 | 2006-04-27 08:46:01 +0200 | [diff] [blame] | 899 | break; |
| 900 | |
Nick Piggin | a60637c | 2008-07-25 19:45:31 -0700 | [diff] [blame] | 901 | if (!page_cache_get_speculative(page)) |
| 902 | goto repeat; |
| 903 | |
| 904 | /* Has the page moved? */ |
| 905 | if (unlikely(page != *((void **)pages[i]))) { |
| 906 | page_cache_release(page); |
| 907 | goto repeat; |
| 908 | } |
| 909 | |
| 910 | pages[ret] = page; |
| 911 | ret++; |
Jens Axboe | ebf4350 | 2006-04-27 08:46:01 +0200 | [diff] [blame] | 912 | index++; |
| 913 | } |
Nick Piggin | a60637c | 2008-07-25 19:45:31 -0700 | [diff] [blame] | 914 | rcu_read_unlock(); |
| 915 | return ret; |
Jens Axboe | ebf4350 | 2006-04-27 08:46:01 +0200 | [diff] [blame] | 916 | } |
David Howells | ef71c15 | 2007-05-09 02:33:44 -0700 | [diff] [blame] | 917 | EXPORT_SYMBOL(find_get_pages_contig); |
Jens Axboe | ebf4350 | 2006-04-27 08:46:01 +0200 | [diff] [blame] | 918 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 919 | /** |
| 920 | * find_get_pages_tag - find and return pages that match @tag |
| 921 | * @mapping: the address_space to search |
| 922 | * @index: the starting page index |
| 923 | * @tag: the tag index |
| 924 | * @nr_pages: the maximum number of pages |
| 925 | * @pages: where the resulting pages are placed |
| 926 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 927 | * 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] | 928 | * @tag. We update @index to index the next page for the traversal. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 929 | */ |
| 930 | unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index, |
| 931 | int tag, unsigned int nr_pages, struct page **pages) |
| 932 | { |
| 933 | unsigned int i; |
| 934 | unsigned int ret; |
Nick Piggin | a60637c | 2008-07-25 19:45:31 -0700 | [diff] [blame] | 935 | unsigned int nr_found; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 936 | |
Nick Piggin | a60637c | 2008-07-25 19:45:31 -0700 | [diff] [blame] | 937 | rcu_read_lock(); |
| 938 | restart: |
| 939 | nr_found = radix_tree_gang_lookup_tag_slot(&mapping->page_tree, |
| 940 | (void ***)pages, *index, nr_pages, tag); |
| 941 | ret = 0; |
| 942 | for (i = 0; i < nr_found; i++) { |
| 943 | struct page *page; |
| 944 | repeat: |
| 945 | page = radix_tree_deref_slot((void **)pages[i]); |
| 946 | if (unlikely(!page)) |
| 947 | continue; |
| 948 | /* |
| 949 | * this can only trigger if nr_found == 1, making livelock |
| 950 | * a non issue. |
| 951 | */ |
| 952 | if (unlikely(page == RADIX_TREE_RETRY)) |
| 953 | goto restart; |
| 954 | |
| 955 | if (!page_cache_get_speculative(page)) |
| 956 | goto repeat; |
| 957 | |
| 958 | /* Has the page moved? */ |
| 959 | if (unlikely(page != *((void **)pages[i]))) { |
| 960 | page_cache_release(page); |
| 961 | goto repeat; |
| 962 | } |
| 963 | |
| 964 | pages[ret] = page; |
| 965 | ret++; |
| 966 | } |
| 967 | rcu_read_unlock(); |
| 968 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 969 | if (ret) |
| 970 | *index = pages[ret - 1]->index + 1; |
Nick Piggin | a60637c | 2008-07-25 19:45:31 -0700 | [diff] [blame] | 971 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 972 | return ret; |
| 973 | } |
David Howells | ef71c15 | 2007-05-09 02:33:44 -0700 | [diff] [blame] | 974 | EXPORT_SYMBOL(find_get_pages_tag); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 975 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 976 | /** |
| 977 | * grab_cache_page_nowait - returns locked page at given index in given cache |
| 978 | * @mapping: target address_space |
| 979 | * @index: the page index |
| 980 | * |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame] | 981 | * 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] | 982 | * This is intended for speculative data generators, where the data can |
| 983 | * be regenerated if the page couldn't be grabbed. This routine should |
| 984 | * be safe to call while holding the lock for another page. |
| 985 | * |
| 986 | * Clear __GFP_FS when allocating the page to avoid recursion into the fs |
| 987 | * and deadlock against the caller's locked page. |
| 988 | */ |
| 989 | struct page * |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 990 | grab_cache_page_nowait(struct address_space *mapping, pgoff_t index) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 991 | { |
| 992 | struct page *page = find_get_page(mapping, index); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 993 | |
| 994 | if (page) { |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 995 | if (trylock_page(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 996 | return page; |
| 997 | page_cache_release(page); |
| 998 | return NULL; |
| 999 | } |
Nick Piggin | 2ae8814 | 2006-10-28 10:38:23 -0700 | [diff] [blame] | 1000 | page = __page_cache_alloc(mapping_gfp_mask(mapping) & ~__GFP_FS); |
Nick Piggin | 67d58ac | 2009-01-06 14:40:28 -0800 | [diff] [blame] | 1001 | if (page && add_to_page_cache_lru(page, mapping, index, GFP_NOFS)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1002 | page_cache_release(page); |
| 1003 | page = NULL; |
| 1004 | } |
| 1005 | return page; |
| 1006 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1007 | EXPORT_SYMBOL(grab_cache_page_nowait); |
| 1008 | |
Wu Fengguang | 76d42bd | 2006-06-25 05:48:43 -0700 | [diff] [blame] | 1009 | /* |
| 1010 | * CD/DVDs are error prone. When a medium error occurs, the driver may fail |
| 1011 | * a _large_ part of the i/o request. Imagine the worst scenario: |
| 1012 | * |
| 1013 | * ---R__________________________________________B__________ |
| 1014 | * ^ reading here ^ bad block(assume 4k) |
| 1015 | * |
| 1016 | * read(R) => miss => readahead(R...B) => media error => frustrating retries |
| 1017 | * => failing the whole request => read(R) => read(R+1) => |
| 1018 | * readahead(R+1...B+1) => bang => read(R+2) => read(R+3) => |
| 1019 | * readahead(R+3...B+2) => bang => read(R+3) => read(R+4) => |
| 1020 | * readahead(R+4...B+3) => bang => read(R+4) => read(R+5) => ...... |
| 1021 | * |
| 1022 | * It is going insane. Fix it by quickly scaling down the readahead size. |
| 1023 | */ |
| 1024 | static void shrink_readahead_size_eio(struct file *filp, |
| 1025 | struct file_ra_state *ra) |
| 1026 | { |
Wu Fengguang | 76d42bd | 2006-06-25 05:48:43 -0700 | [diff] [blame] | 1027 | ra->ra_pages /= 4; |
Wu Fengguang | 76d42bd | 2006-06-25 05:48:43 -0700 | [diff] [blame] | 1028 | } |
| 1029 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 1030 | /** |
Christoph Hellwig | 36e7891 | 2008-02-08 04:21:24 -0800 | [diff] [blame] | 1031 | * do_generic_file_read - generic file read routine |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 1032 | * @filp: the file to read |
| 1033 | * @ppos: current file position |
| 1034 | * @desc: read_descriptor |
| 1035 | * @actor: read method |
| 1036 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1037 | * This is a generic file read routine, and uses the |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 1038 | * mapping->a_ops->readpage() function for the actual low-level stuff. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1039 | * |
| 1040 | * This is really ugly. But the goto's actually try to clarify some |
| 1041 | * of the logic when it comes to error handling etc. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1042 | */ |
Christoph Hellwig | 36e7891 | 2008-02-08 04:21:24 -0800 | [diff] [blame] | 1043 | static void do_generic_file_read(struct file *filp, loff_t *ppos, |
| 1044 | read_descriptor_t *desc, read_actor_t actor) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1045 | { |
Christoph Hellwig | 36e7891 | 2008-02-08 04:21:24 -0800 | [diff] [blame] | 1046 | struct address_space *mapping = filp->f_mapping; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1047 | struct inode *inode = mapping->host; |
Christoph Hellwig | 36e7891 | 2008-02-08 04:21:24 -0800 | [diff] [blame] | 1048 | struct file_ra_state *ra = &filp->f_ra; |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 1049 | pgoff_t index; |
| 1050 | pgoff_t last_index; |
| 1051 | pgoff_t prev_index; |
| 1052 | unsigned long offset; /* offset into pagecache page */ |
Jan Kara | ec0f163 | 2007-05-06 14:49:25 -0700 | [diff] [blame] | 1053 | unsigned int prev_offset; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1054 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1055 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1056 | index = *ppos >> PAGE_CACHE_SHIFT; |
Fengguang Wu | 7ff8107 | 2007-10-16 01:24:35 -0700 | [diff] [blame] | 1057 | prev_index = ra->prev_pos >> PAGE_CACHE_SHIFT; |
| 1058 | prev_offset = ra->prev_pos & (PAGE_CACHE_SIZE-1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1059 | last_index = (*ppos + desc->count + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT; |
| 1060 | offset = *ppos & ~PAGE_CACHE_MASK; |
| 1061 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1062 | for (;;) { |
| 1063 | struct page *page; |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 1064 | pgoff_t end_index; |
NeilBrown | a32ea1e | 2007-07-17 04:03:04 -0700 | [diff] [blame] | 1065 | loff_t isize; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1066 | unsigned long nr, ret; |
| 1067 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1068 | cond_resched(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1069 | find_page: |
| 1070 | page = find_get_page(mapping, index); |
Fengguang Wu | 3ea89ee | 2007-07-19 01:48:02 -0700 | [diff] [blame] | 1071 | if (!page) { |
Rusty Russell | cf914a7 | 2007-07-19 01:48:08 -0700 | [diff] [blame] | 1072 | page_cache_sync_readahead(mapping, |
Fengguang Wu | 7ff8107 | 2007-10-16 01:24:35 -0700 | [diff] [blame] | 1073 | ra, filp, |
Fengguang Wu | 3ea89ee | 2007-07-19 01:48:02 -0700 | [diff] [blame] | 1074 | index, last_index - index); |
| 1075 | page = find_get_page(mapping, index); |
| 1076 | if (unlikely(page == NULL)) |
| 1077 | goto no_cached_page; |
| 1078 | } |
| 1079 | if (PageReadahead(page)) { |
Rusty Russell | cf914a7 | 2007-07-19 01:48:08 -0700 | [diff] [blame] | 1080 | page_cache_async_readahead(mapping, |
Fengguang Wu | 7ff8107 | 2007-10-16 01:24:35 -0700 | [diff] [blame] | 1081 | ra, filp, page, |
Fengguang Wu | 3ea89ee | 2007-07-19 01:48:02 -0700 | [diff] [blame] | 1082 | index, last_index - index); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1083 | } |
Hisashi Hifumi | 8ab22b9 | 2008-07-28 15:46:36 -0700 | [diff] [blame] | 1084 | if (!PageUptodate(page)) { |
| 1085 | if (inode->i_blkbits == PAGE_CACHE_SHIFT || |
| 1086 | !mapping->a_ops->is_partially_uptodate) |
| 1087 | goto page_not_up_to_date; |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 1088 | if (!trylock_page(page)) |
Hisashi Hifumi | 8ab22b9 | 2008-07-28 15:46:36 -0700 | [diff] [blame] | 1089 | goto page_not_up_to_date; |
| 1090 | if (!mapping->a_ops->is_partially_uptodate(page, |
| 1091 | desc, offset)) |
| 1092 | goto page_not_up_to_date_locked; |
| 1093 | unlock_page(page); |
| 1094 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1095 | page_ok: |
NeilBrown | a32ea1e | 2007-07-17 04:03:04 -0700 | [diff] [blame] | 1096 | /* |
| 1097 | * i_size must be checked after we know the page is Uptodate. |
| 1098 | * |
| 1099 | * Checking i_size after the check allows us to calculate |
| 1100 | * the correct value for "nr", which means the zero-filled |
| 1101 | * part of the page is not copied back to userspace (unless |
| 1102 | * another truncate extends the file - this is desired though). |
| 1103 | */ |
| 1104 | |
| 1105 | isize = i_size_read(inode); |
| 1106 | end_index = (isize - 1) >> PAGE_CACHE_SHIFT; |
| 1107 | if (unlikely(!isize || index > end_index)) { |
| 1108 | page_cache_release(page); |
| 1109 | goto out; |
| 1110 | } |
| 1111 | |
| 1112 | /* nr is the maximum number of bytes to copy from this page */ |
| 1113 | nr = PAGE_CACHE_SIZE; |
| 1114 | if (index == end_index) { |
| 1115 | nr = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; |
| 1116 | if (nr <= offset) { |
| 1117 | page_cache_release(page); |
| 1118 | goto out; |
| 1119 | } |
| 1120 | } |
| 1121 | nr = nr - offset; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1122 | |
| 1123 | /* If users can be writing to this page using arbitrary |
| 1124 | * virtual addresses, take care about potential aliasing |
| 1125 | * before reading the page on the kernel side. |
| 1126 | */ |
| 1127 | if (mapping_writably_mapped(mapping)) |
| 1128 | flush_dcache_page(page); |
| 1129 | |
| 1130 | /* |
Jan Kara | ec0f163 | 2007-05-06 14:49:25 -0700 | [diff] [blame] | 1131 | * When a sequential read accesses a page several times, |
| 1132 | * only mark it as accessed the first time. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1133 | */ |
Jan Kara | ec0f163 | 2007-05-06 14:49:25 -0700 | [diff] [blame] | 1134 | if (prev_index != index || offset != prev_offset) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1135 | mark_page_accessed(page); |
| 1136 | prev_index = index; |
| 1137 | |
| 1138 | /* |
| 1139 | * Ok, we have the page, and it's up-to-date, so |
| 1140 | * now we can copy it to user space... |
| 1141 | * |
| 1142 | * The actor routine returns how many bytes were actually used.. |
| 1143 | * NOTE! This may not be the same as how much of a user buffer |
| 1144 | * we filled up (we may be padding etc), so we can only update |
| 1145 | * "pos" here (the actor routine has to update the user buffer |
| 1146 | * pointers and the remaining count). |
| 1147 | */ |
| 1148 | ret = actor(desc, page, offset, nr); |
| 1149 | offset += ret; |
| 1150 | index += offset >> PAGE_CACHE_SHIFT; |
| 1151 | offset &= ~PAGE_CACHE_MASK; |
Jan Kara | 6ce745e | 2007-05-06 14:49:26 -0700 | [diff] [blame] | 1152 | prev_offset = offset; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1153 | |
| 1154 | page_cache_release(page); |
| 1155 | if (ret == nr && desc->count) |
| 1156 | continue; |
| 1157 | goto out; |
| 1158 | |
| 1159 | page_not_up_to_date: |
| 1160 | /* Get exclusive access to the page ... */ |
Oleg Nesterov | 8546232 | 2008-06-08 21:20:43 +0400 | [diff] [blame] | 1161 | error = lock_page_killable(page); |
| 1162 | if (unlikely(error)) |
| 1163 | goto readpage_error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1164 | |
Hisashi Hifumi | 8ab22b9 | 2008-07-28 15:46:36 -0700 | [diff] [blame] | 1165 | page_not_up_to_date_locked: |
Nick Piggin | da6052f | 2006-09-25 23:31:35 -0700 | [diff] [blame] | 1166 | /* Did it get truncated before we got the lock? */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1167 | if (!page->mapping) { |
| 1168 | unlock_page(page); |
| 1169 | page_cache_release(page); |
| 1170 | continue; |
| 1171 | } |
| 1172 | |
| 1173 | /* Did somebody else fill it already? */ |
| 1174 | if (PageUptodate(page)) { |
| 1175 | unlock_page(page); |
| 1176 | goto page_ok; |
| 1177 | } |
| 1178 | |
| 1179 | readpage: |
| 1180 | /* Start the actual read. The read will unlock the page. */ |
| 1181 | error = mapping->a_ops->readpage(filp, page); |
| 1182 | |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 1183 | if (unlikely(error)) { |
| 1184 | if (error == AOP_TRUNCATED_PAGE) { |
| 1185 | page_cache_release(page); |
| 1186 | goto find_page; |
| 1187 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1188 | goto readpage_error; |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 1189 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1190 | |
| 1191 | if (!PageUptodate(page)) { |
Oleg Nesterov | 8546232 | 2008-06-08 21:20:43 +0400 | [diff] [blame] | 1192 | error = lock_page_killable(page); |
| 1193 | if (unlikely(error)) |
| 1194 | goto readpage_error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1195 | if (!PageUptodate(page)) { |
| 1196 | if (page->mapping == NULL) { |
| 1197 | /* |
| 1198 | * invalidate_inode_pages got it |
| 1199 | */ |
| 1200 | unlock_page(page); |
| 1201 | page_cache_release(page); |
| 1202 | goto find_page; |
| 1203 | } |
| 1204 | unlock_page(page); |
Fengguang Wu | 7ff8107 | 2007-10-16 01:24:35 -0700 | [diff] [blame] | 1205 | shrink_readahead_size_eio(filp, ra); |
Oleg Nesterov | 8546232 | 2008-06-08 21:20:43 +0400 | [diff] [blame] | 1206 | error = -EIO; |
| 1207 | goto readpage_error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1208 | } |
| 1209 | unlock_page(page); |
| 1210 | } |
| 1211 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1212 | goto page_ok; |
| 1213 | |
| 1214 | readpage_error: |
| 1215 | /* UHHUH! A synchronous read error occurred. Report it */ |
| 1216 | desc->error = error; |
| 1217 | page_cache_release(page); |
| 1218 | goto out; |
| 1219 | |
| 1220 | no_cached_page: |
| 1221 | /* |
| 1222 | * Ok, it wasn't cached, so we need to create a new |
| 1223 | * page.. |
| 1224 | */ |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 1225 | page = page_cache_alloc_cold(mapping); |
| 1226 | if (!page) { |
| 1227 | desc->error = -ENOMEM; |
| 1228 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1229 | } |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 1230 | error = add_to_page_cache_lru(page, mapping, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1231 | index, GFP_KERNEL); |
| 1232 | if (error) { |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 1233 | page_cache_release(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1234 | if (error == -EEXIST) |
| 1235 | goto find_page; |
| 1236 | desc->error = error; |
| 1237 | goto out; |
| 1238 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1239 | goto readpage; |
| 1240 | } |
| 1241 | |
| 1242 | out: |
Fengguang Wu | 7ff8107 | 2007-10-16 01:24:35 -0700 | [diff] [blame] | 1243 | ra->prev_pos = prev_index; |
| 1244 | ra->prev_pos <<= PAGE_CACHE_SHIFT; |
| 1245 | ra->prev_pos |= prev_offset; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1246 | |
Fengguang Wu | f4e6b49 | 2007-10-16 01:24:33 -0700 | [diff] [blame] | 1247 | *ppos = ((loff_t)index << PAGE_CACHE_SHIFT) + offset; |
Krishna Kumar | 0c6aa26 | 2008-10-15 22:01:13 -0700 | [diff] [blame] | 1248 | file_accessed(filp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1249 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1250 | |
| 1251 | int file_read_actor(read_descriptor_t *desc, struct page *page, |
| 1252 | unsigned long offset, unsigned long size) |
| 1253 | { |
| 1254 | char *kaddr; |
| 1255 | unsigned long left, count = desc->count; |
| 1256 | |
| 1257 | if (size > count) |
| 1258 | size = count; |
| 1259 | |
| 1260 | /* |
| 1261 | * Faults on the destination of a read are common, so do it before |
| 1262 | * taking the kmap. |
| 1263 | */ |
| 1264 | if (!fault_in_pages_writeable(desc->arg.buf, size)) { |
| 1265 | kaddr = kmap_atomic(page, KM_USER0); |
| 1266 | left = __copy_to_user_inatomic(desc->arg.buf, |
| 1267 | kaddr + offset, size); |
| 1268 | kunmap_atomic(kaddr, KM_USER0); |
| 1269 | if (left == 0) |
| 1270 | goto success; |
| 1271 | } |
| 1272 | |
| 1273 | /* Do it the slow way */ |
| 1274 | kaddr = kmap(page); |
| 1275 | left = __copy_to_user(desc->arg.buf, kaddr + offset, size); |
| 1276 | kunmap(page); |
| 1277 | |
| 1278 | if (left) { |
| 1279 | size -= left; |
| 1280 | desc->error = -EFAULT; |
| 1281 | } |
| 1282 | success: |
| 1283 | desc->count = count - size; |
| 1284 | desc->written += size; |
| 1285 | desc->arg.buf += size; |
| 1286 | return size; |
| 1287 | } |
| 1288 | |
Dmitriy Monakhov | 0ceb331 | 2007-05-08 00:23:02 -0700 | [diff] [blame] | 1289 | /* |
| 1290 | * Performs necessary checks before doing a write |
| 1291 | * @iov: io vector request |
| 1292 | * @nr_segs: number of segments in the iovec |
| 1293 | * @count: number of bytes to write |
| 1294 | * @access_flags: type of access: %VERIFY_READ or %VERIFY_WRITE |
| 1295 | * |
| 1296 | * Adjust number of segments and amount of bytes to write (nr_segs should be |
| 1297 | * properly initialized first). Returns appropriate error code that caller |
| 1298 | * should return or zero in case that write should be allowed. |
| 1299 | */ |
| 1300 | int generic_segment_checks(const struct iovec *iov, |
| 1301 | unsigned long *nr_segs, size_t *count, int access_flags) |
| 1302 | { |
| 1303 | unsigned long seg; |
| 1304 | size_t cnt = 0; |
| 1305 | for (seg = 0; seg < *nr_segs; seg++) { |
| 1306 | const struct iovec *iv = &iov[seg]; |
| 1307 | |
| 1308 | /* |
| 1309 | * If any segment has a negative length, or the cumulative |
| 1310 | * length ever wraps negative then return -EINVAL. |
| 1311 | */ |
| 1312 | cnt += iv->iov_len; |
| 1313 | if (unlikely((ssize_t)(cnt|iv->iov_len) < 0)) |
| 1314 | return -EINVAL; |
| 1315 | if (access_ok(access_flags, iv->iov_base, iv->iov_len)) |
| 1316 | continue; |
| 1317 | if (seg == 0) |
| 1318 | return -EFAULT; |
| 1319 | *nr_segs = seg; |
| 1320 | cnt -= iv->iov_len; /* This segment is no good */ |
| 1321 | break; |
| 1322 | } |
| 1323 | *count = cnt; |
| 1324 | return 0; |
| 1325 | } |
| 1326 | EXPORT_SYMBOL(generic_segment_checks); |
| 1327 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 1328 | /** |
Henrik Kretzschmar | b2abacf | 2006-10-04 02:15:22 -0700 | [diff] [blame] | 1329 | * generic_file_aio_read - generic filesystem read routine |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 1330 | * @iocb: kernel I/O control block |
| 1331 | * @iov: io vector request |
| 1332 | * @nr_segs: number of segments in the iovec |
Henrik Kretzschmar | b2abacf | 2006-10-04 02:15:22 -0700 | [diff] [blame] | 1333 | * @pos: current file position |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 1334 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1335 | * This is the "read()" routine for all filesystems |
| 1336 | * that can use the page cache directly. |
| 1337 | */ |
| 1338 | ssize_t |
Badari Pulavarty | 543ade1 | 2006-09-30 23:28:48 -0700 | [diff] [blame] | 1339 | generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, |
| 1340 | unsigned long nr_segs, loff_t pos) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1341 | { |
| 1342 | struct file *filp = iocb->ki_filp; |
| 1343 | ssize_t retval; |
| 1344 | unsigned long seg; |
| 1345 | size_t count; |
Badari Pulavarty | 543ade1 | 2006-09-30 23:28:48 -0700 | [diff] [blame] | 1346 | loff_t *ppos = &iocb->ki_pos; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1347 | |
| 1348 | count = 0; |
Dmitriy Monakhov | 0ceb331 | 2007-05-08 00:23:02 -0700 | [diff] [blame] | 1349 | retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE); |
| 1350 | if (retval) |
| 1351 | return retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1352 | |
| 1353 | /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */ |
| 1354 | if (filp->f_flags & O_DIRECT) { |
Badari Pulavarty | 543ade1 | 2006-09-30 23:28:48 -0700 | [diff] [blame] | 1355 | loff_t size; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1356 | struct address_space *mapping; |
| 1357 | struct inode *inode; |
| 1358 | |
| 1359 | mapping = filp->f_mapping; |
| 1360 | inode = mapping->host; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1361 | if (!count) |
| 1362 | goto out; /* skip atime */ |
| 1363 | size = i_size_read(inode); |
| 1364 | if (pos < size) { |
Nick Piggin | 48b47c5 | 2009-01-06 14:40:22 -0800 | [diff] [blame] | 1365 | retval = filemap_write_and_wait_range(mapping, pos, |
| 1366 | pos + iov_length(iov, nr_segs) - 1); |
Christoph Hellwig | a969e90 | 2008-07-23 21:27:04 -0700 | [diff] [blame] | 1367 | if (!retval) { |
| 1368 | retval = mapping->a_ops->direct_IO(READ, iocb, |
| 1369 | iov, pos, nr_segs); |
| 1370 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1371 | if (retval > 0) |
| 1372 | *ppos = pos + retval; |
Hugh Dickins | 11fa977 | 2008-07-23 21:27:34 -0700 | [diff] [blame] | 1373 | if (retval) { |
| 1374 | file_accessed(filp); |
| 1375 | goto out; |
| 1376 | } |
Steven Whitehouse | 0e0bcae | 2006-09-27 14:45:07 -0400 | [diff] [blame] | 1377 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1378 | } |
| 1379 | |
Hugh Dickins | 11fa977 | 2008-07-23 21:27:34 -0700 | [diff] [blame] | 1380 | for (seg = 0; seg < nr_segs; seg++) { |
| 1381 | read_descriptor_t desc; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1382 | |
Hugh Dickins | 11fa977 | 2008-07-23 21:27:34 -0700 | [diff] [blame] | 1383 | desc.written = 0; |
| 1384 | desc.arg.buf = iov[seg].iov_base; |
| 1385 | desc.count = iov[seg].iov_len; |
| 1386 | if (desc.count == 0) |
| 1387 | continue; |
| 1388 | desc.error = 0; |
| 1389 | do_generic_file_read(filp, ppos, &desc, file_read_actor); |
| 1390 | retval += desc.written; |
| 1391 | if (desc.error) { |
| 1392 | retval = retval ?: desc.error; |
| 1393 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1394 | } |
Hugh Dickins | 11fa977 | 2008-07-23 21:27:34 -0700 | [diff] [blame] | 1395 | if (desc.count > 0) |
| 1396 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1397 | } |
| 1398 | out: |
| 1399 | return retval; |
| 1400 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1401 | EXPORT_SYMBOL(generic_file_aio_read); |
| 1402 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1403 | static ssize_t |
| 1404 | do_readahead(struct address_space *mapping, struct file *filp, |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 1405 | pgoff_t index, unsigned long nr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1406 | { |
| 1407 | if (!mapping || !mapping->a_ops || !mapping->a_ops->readpage) |
| 1408 | return -EINVAL; |
| 1409 | |
Wu Fengguang | f7e839d | 2009-06-16 15:31:20 -0700 | [diff] [blame] | 1410 | force_page_cache_readahead(mapping, filp, index, nr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1411 | return 0; |
| 1412 | } |
| 1413 | |
Heiko Carstens | 6673e0c | 2009-01-14 14:14:02 +0100 | [diff] [blame] | 1414 | SYSCALL_DEFINE(readahead)(int fd, loff_t offset, size_t count) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1415 | { |
| 1416 | ssize_t ret; |
| 1417 | struct file *file; |
| 1418 | |
| 1419 | ret = -EBADF; |
| 1420 | file = fget(fd); |
| 1421 | if (file) { |
| 1422 | if (file->f_mode & FMODE_READ) { |
| 1423 | struct address_space *mapping = file->f_mapping; |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 1424 | pgoff_t start = offset >> PAGE_CACHE_SHIFT; |
| 1425 | pgoff_t end = (offset + count - 1) >> PAGE_CACHE_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1426 | unsigned long len = end - start + 1; |
| 1427 | ret = do_readahead(mapping, file, start, len); |
| 1428 | } |
| 1429 | fput(file); |
| 1430 | } |
| 1431 | return ret; |
| 1432 | } |
Heiko Carstens | 6673e0c | 2009-01-14 14:14:02 +0100 | [diff] [blame] | 1433 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS |
| 1434 | asmlinkage long SyS_readahead(long fd, loff_t offset, long count) |
| 1435 | { |
| 1436 | return SYSC_readahead((int) fd, offset, (size_t) count); |
| 1437 | } |
| 1438 | SYSCALL_ALIAS(sys_readahead, SyS_readahead); |
| 1439 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1440 | |
| 1441 | #ifdef CONFIG_MMU |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 1442 | /** |
| 1443 | * page_cache_read - adds requested page to the page cache if not already there |
| 1444 | * @file: file to read |
| 1445 | * @offset: page index |
| 1446 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1447 | * This adds the requested page to the page cache if it isn't already there, |
| 1448 | * and schedules an I/O to read in its contents from disk. |
| 1449 | */ |
Harvey Harrison | 920c7a5 | 2008-02-04 22:29:26 -0800 | [diff] [blame] | 1450 | static int page_cache_read(struct file *file, pgoff_t offset) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1451 | { |
| 1452 | struct address_space *mapping = file->f_mapping; |
| 1453 | struct page *page; |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 1454 | int ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1455 | |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 1456 | do { |
| 1457 | page = page_cache_alloc_cold(mapping); |
| 1458 | if (!page) |
| 1459 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1460 | |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 1461 | ret = add_to_page_cache_lru(page, mapping, offset, GFP_KERNEL); |
| 1462 | if (ret == 0) |
| 1463 | ret = mapping->a_ops->readpage(file, page); |
| 1464 | else if (ret == -EEXIST) |
| 1465 | ret = 0; /* losing race to add is OK */ |
| 1466 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1467 | page_cache_release(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1468 | |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 1469 | } while (ret == AOP_TRUNCATED_PAGE); |
| 1470 | |
| 1471 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1472 | } |
| 1473 | |
| 1474 | #define MMAP_LOTSAMISS (100) |
| 1475 | |
Linus Torvalds | ef00e08 | 2009-06-16 15:31:25 -0700 | [diff] [blame] | 1476 | /* |
| 1477 | * Synchronous readahead happens when we don't even find |
| 1478 | * a page in the page cache at all. |
| 1479 | */ |
| 1480 | static void do_sync_mmap_readahead(struct vm_area_struct *vma, |
| 1481 | struct file_ra_state *ra, |
| 1482 | struct file *file, |
| 1483 | pgoff_t offset) |
| 1484 | { |
| 1485 | unsigned long ra_pages; |
| 1486 | struct address_space *mapping = file->f_mapping; |
| 1487 | |
| 1488 | /* If we don't want any read-ahead, don't bother */ |
| 1489 | if (VM_RandomReadHint(vma)) |
| 1490 | return; |
| 1491 | |
Wu Fengguang | 70ac23c | 2009-06-16 15:31:28 -0700 | [diff] [blame] | 1492 | if (VM_SequentialReadHint(vma) || |
| 1493 | offset - 1 == (ra->prev_pos >> PAGE_CACHE_SHIFT)) { |
Wu Fengguang | 7ffc59b | 2009-06-16 15:31:38 -0700 | [diff] [blame] | 1494 | page_cache_sync_readahead(mapping, ra, file, offset, |
| 1495 | ra->ra_pages); |
Linus Torvalds | ef00e08 | 2009-06-16 15:31:25 -0700 | [diff] [blame] | 1496 | return; |
| 1497 | } |
| 1498 | |
| 1499 | if (ra->mmap_miss < INT_MAX) |
| 1500 | ra->mmap_miss++; |
| 1501 | |
| 1502 | /* |
| 1503 | * Do we miss much more than hit in this file? If so, |
| 1504 | * stop bothering with read-ahead. It will only hurt. |
| 1505 | */ |
| 1506 | if (ra->mmap_miss > MMAP_LOTSAMISS) |
| 1507 | return; |
| 1508 | |
Wu Fengguang | d30a110 | 2009-06-16 15:31:30 -0700 | [diff] [blame] | 1509 | /* |
| 1510 | * mmap read-around |
| 1511 | */ |
Linus Torvalds | ef00e08 | 2009-06-16 15:31:25 -0700 | [diff] [blame] | 1512 | ra_pages = max_sane_readahead(ra->ra_pages); |
| 1513 | if (ra_pages) { |
Wu Fengguang | d30a110 | 2009-06-16 15:31:30 -0700 | [diff] [blame] | 1514 | ra->start = max_t(long, 0, offset - ra_pages/2); |
| 1515 | ra->size = ra_pages; |
| 1516 | ra->async_size = 0; |
| 1517 | ra_submit(ra, mapping, file); |
Linus Torvalds | ef00e08 | 2009-06-16 15:31:25 -0700 | [diff] [blame] | 1518 | } |
| 1519 | } |
| 1520 | |
| 1521 | /* |
| 1522 | * Asynchronous readahead happens when we find the page and PG_readahead, |
| 1523 | * so we want to possibly extend the readahead further.. |
| 1524 | */ |
| 1525 | static void do_async_mmap_readahead(struct vm_area_struct *vma, |
| 1526 | struct file_ra_state *ra, |
| 1527 | struct file *file, |
| 1528 | struct page *page, |
| 1529 | pgoff_t offset) |
| 1530 | { |
| 1531 | struct address_space *mapping = file->f_mapping; |
| 1532 | |
| 1533 | /* If we don't want any read-ahead, don't bother */ |
| 1534 | if (VM_RandomReadHint(vma)) |
| 1535 | return; |
| 1536 | if (ra->mmap_miss > 0) |
| 1537 | ra->mmap_miss--; |
| 1538 | if (PageReadahead(page)) |
Wu Fengguang | 2fad6f5 | 2009-06-16 15:31:29 -0700 | [diff] [blame] | 1539 | page_cache_async_readahead(mapping, ra, file, |
| 1540 | page, offset, ra->ra_pages); |
Linus Torvalds | ef00e08 | 2009-06-16 15:31:25 -0700 | [diff] [blame] | 1541 | } |
| 1542 | |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 1543 | /** |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 1544 | * filemap_fault - read in file data for page fault handling |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1545 | * @vma: vma in which the fault was taken |
| 1546 | * @vmf: struct vm_fault containing details of the fault |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 1547 | * |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 1548 | * filemap_fault() is invoked via the vma operations vector for a |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1549 | * mapped memory region to read in file data during a page fault. |
| 1550 | * |
| 1551 | * The goto's are kind of ugly, but this streamlines the normal case of having |
| 1552 | * it in the page cache, and handles the special cases reasonably without |
| 1553 | * having a lot of duplicated code. |
| 1554 | */ |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1555 | int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1556 | { |
| 1557 | int error; |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 1558 | struct file *file = vma->vm_file; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1559 | struct address_space *mapping = file->f_mapping; |
| 1560 | struct file_ra_state *ra = &file->f_ra; |
| 1561 | struct inode *inode = mapping->host; |
Linus Torvalds | ef00e08 | 2009-06-16 15:31:25 -0700 | [diff] [blame] | 1562 | pgoff_t offset = vmf->pgoff; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1563 | struct page *page; |
Jan Kara | 2004dc8 | 2008-02-08 04:20:11 -0800 | [diff] [blame] | 1564 | pgoff_t size; |
Nick Piggin | 83c5407 | 2007-07-19 01:47:05 -0700 | [diff] [blame] | 1565 | int ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1566 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1567 | size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
Linus Torvalds | ef00e08 | 2009-06-16 15:31:25 -0700 | [diff] [blame] | 1568 | if (offset >= size) |
Linus Torvalds | 5307cc1 | 2007-10-31 09:19:46 -0700 | [diff] [blame] | 1569 | return VM_FAULT_SIGBUS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1570 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1571 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1572 | * Do we have something in the page cache already? |
| 1573 | */ |
Linus Torvalds | ef00e08 | 2009-06-16 15:31:25 -0700 | [diff] [blame] | 1574 | page = find_get_page(mapping, offset); |
| 1575 | if (likely(page)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1576 | /* |
Linus Torvalds | ef00e08 | 2009-06-16 15:31:25 -0700 | [diff] [blame] | 1577 | * We found the page, so try async readahead before |
| 1578 | * waiting for the lock. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1579 | */ |
Linus Torvalds | ef00e08 | 2009-06-16 15:31:25 -0700 | [diff] [blame] | 1580 | do_async_mmap_readahead(vma, ra, file, page, offset); |
| 1581 | lock_page(page); |
| 1582 | |
| 1583 | /* Did it get truncated? */ |
| 1584 | if (unlikely(page->mapping != mapping)) { |
| 1585 | unlock_page(page); |
| 1586 | put_page(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1587 | goto no_cached_page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1588 | } |
Linus Torvalds | ef00e08 | 2009-06-16 15:31:25 -0700 | [diff] [blame] | 1589 | } else { |
| 1590 | /* No page in the page cache at all */ |
| 1591 | do_sync_mmap_readahead(vma, ra, file, offset); |
| 1592 | count_vm_event(PGMAJFAULT); |
| 1593 | ret = VM_FAULT_MAJOR; |
| 1594 | retry_find: |
| 1595 | page = find_lock_page(mapping, offset); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1596 | if (!page) |
| 1597 | goto no_cached_page; |
| 1598 | } |
| 1599 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1600 | /* |
Nick Piggin | d00806b | 2007-07-19 01:46:57 -0700 | [diff] [blame] | 1601 | * We have a locked page in the page cache, now we need to check |
| 1602 | * 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] | 1603 | */ |
Nick Piggin | d00806b | 2007-07-19 01:46:57 -0700 | [diff] [blame] | 1604 | if (unlikely(!PageUptodate(page))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1605 | goto page_not_uptodate; |
| 1606 | |
Linus Torvalds | ef00e08 | 2009-06-16 15:31:25 -0700 | [diff] [blame] | 1607 | /* |
| 1608 | * Found the page and have a reference on it. |
| 1609 | * We must recheck i_size under page lock. |
| 1610 | */ |
Nick Piggin | d00806b | 2007-07-19 01:46:57 -0700 | [diff] [blame] | 1611 | size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
Linus Torvalds | ef00e08 | 2009-06-16 15:31:25 -0700 | [diff] [blame] | 1612 | if (unlikely(offset >= size)) { |
Nick Piggin | d00806b | 2007-07-19 01:46:57 -0700 | [diff] [blame] | 1613 | unlock_page(page); |
Yan Zheng | 745ad48 | 2007-10-08 10:08:37 -0700 | [diff] [blame] | 1614 | page_cache_release(page); |
Linus Torvalds | 5307cc1 | 2007-10-31 09:19:46 -0700 | [diff] [blame] | 1615 | return VM_FAULT_SIGBUS; |
Nick Piggin | d00806b | 2007-07-19 01:46:57 -0700 | [diff] [blame] | 1616 | } |
| 1617 | |
Linus Torvalds | ef00e08 | 2009-06-16 15:31:25 -0700 | [diff] [blame] | 1618 | ra->prev_pos = (loff_t)offset << PAGE_CACHE_SHIFT; |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1619 | vmf->page = page; |
Nick Piggin | 83c5407 | 2007-07-19 01:47:05 -0700 | [diff] [blame] | 1620 | return ret | VM_FAULT_LOCKED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1621 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1622 | no_cached_page: |
| 1623 | /* |
| 1624 | * We're only likely to ever get here if MADV_RANDOM is in |
| 1625 | * effect. |
| 1626 | */ |
Linus Torvalds | ef00e08 | 2009-06-16 15:31:25 -0700 | [diff] [blame] | 1627 | error = page_cache_read(file, offset); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1628 | |
| 1629 | /* |
| 1630 | * The page we want has now been added to the page cache. |
| 1631 | * In the unlikely event that someone removed it in the |
| 1632 | * meantime, we'll just come back here and read it again. |
| 1633 | */ |
| 1634 | if (error >= 0) |
| 1635 | goto retry_find; |
| 1636 | |
| 1637 | /* |
| 1638 | * An error return from page_cache_read can result if the |
| 1639 | * system is low on memory, or a problem occurs while trying |
| 1640 | * to schedule I/O. |
| 1641 | */ |
| 1642 | if (error == -ENOMEM) |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1643 | return VM_FAULT_OOM; |
| 1644 | return VM_FAULT_SIGBUS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1645 | |
| 1646 | page_not_uptodate: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1647 | /* |
| 1648 | * Umm, take care of errors if the page isn't up-to-date. |
| 1649 | * Try to re-read it _once_. We do this synchronously, |
| 1650 | * because there really aren't any performance issues here |
| 1651 | * and we need to check for errors. |
| 1652 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1653 | ClearPageError(page); |
Zach Brown | 994fc28c | 2005-12-15 14:28:17 -0800 | [diff] [blame] | 1654 | error = mapping->a_ops->readpage(file, page); |
Miklos Szeredi | 3ef0f72 | 2008-05-14 16:05:37 -0700 | [diff] [blame] | 1655 | if (!error) { |
| 1656 | wait_on_page_locked(page); |
| 1657 | if (!PageUptodate(page)) |
| 1658 | error = -EIO; |
| 1659 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1660 | page_cache_release(page); |
Nick Piggin | d00806b | 2007-07-19 01:46:57 -0700 | [diff] [blame] | 1661 | |
| 1662 | if (!error || error == AOP_TRUNCATED_PAGE) |
| 1663 | goto retry_find; |
| 1664 | |
| 1665 | /* Things didn't work out. Return zero to tell the mm layer so. */ |
| 1666 | shrink_readahead_size_eio(file, ra); |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1667 | return VM_FAULT_SIGBUS; |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 1668 | } |
| 1669 | EXPORT_SYMBOL(filemap_fault); |
| 1670 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1671 | struct vm_operations_struct generic_file_vm_ops = { |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 1672 | .fault = filemap_fault, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1673 | }; |
| 1674 | |
| 1675 | /* This is used for a general mmap of a disk file */ |
| 1676 | |
| 1677 | int generic_file_mmap(struct file * file, struct vm_area_struct * vma) |
| 1678 | { |
| 1679 | struct address_space *mapping = file->f_mapping; |
| 1680 | |
| 1681 | if (!mapping->a_ops->readpage) |
| 1682 | return -ENOEXEC; |
| 1683 | file_accessed(file); |
| 1684 | vma->vm_ops = &generic_file_vm_ops; |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 1685 | vma->vm_flags |= VM_CAN_NONLINEAR; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1686 | return 0; |
| 1687 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1688 | |
| 1689 | /* |
| 1690 | * This is for filesystems which do not implement ->writepage. |
| 1691 | */ |
| 1692 | int generic_file_readonly_mmap(struct file *file, struct vm_area_struct *vma) |
| 1693 | { |
| 1694 | if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) |
| 1695 | return -EINVAL; |
| 1696 | return generic_file_mmap(file, vma); |
| 1697 | } |
| 1698 | #else |
| 1699 | int generic_file_mmap(struct file * file, struct vm_area_struct * vma) |
| 1700 | { |
| 1701 | return -ENOSYS; |
| 1702 | } |
| 1703 | int generic_file_readonly_mmap(struct file * file, struct vm_area_struct * vma) |
| 1704 | { |
| 1705 | return -ENOSYS; |
| 1706 | } |
| 1707 | #endif /* CONFIG_MMU */ |
| 1708 | |
| 1709 | EXPORT_SYMBOL(generic_file_mmap); |
| 1710 | EXPORT_SYMBOL(generic_file_readonly_mmap); |
| 1711 | |
Nick Piggin | 6fe6900 | 2007-05-06 14:49:04 -0700 | [diff] [blame] | 1712 | static struct page *__read_cache_page(struct address_space *mapping, |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 1713 | pgoff_t index, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1714 | int (*filler)(void *,struct page*), |
| 1715 | void *data) |
| 1716 | { |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 1717 | struct page *page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1718 | int err; |
| 1719 | repeat: |
| 1720 | page = find_get_page(mapping, index); |
| 1721 | if (!page) { |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 1722 | page = page_cache_alloc_cold(mapping); |
| 1723 | if (!page) |
| 1724 | return ERR_PTR(-ENOMEM); |
| 1725 | err = add_to_page_cache_lru(page, mapping, index, GFP_KERNEL); |
| 1726 | if (unlikely(err)) { |
| 1727 | page_cache_release(page); |
| 1728 | if (err == -EEXIST) |
| 1729 | goto repeat; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1730 | /* Presumably ENOMEM for radix tree node */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1731 | return ERR_PTR(err); |
| 1732 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1733 | err = filler(data, page); |
| 1734 | if (err < 0) { |
| 1735 | page_cache_release(page); |
| 1736 | page = ERR_PTR(err); |
| 1737 | } |
| 1738 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1739 | return page; |
| 1740 | } |
| 1741 | |
Randy Dunlap | 7682486 | 2008-03-19 17:00:40 -0700 | [diff] [blame] | 1742 | /** |
| 1743 | * read_cache_page_async - read into page cache, fill it if needed |
| 1744 | * @mapping: the page's address_space |
| 1745 | * @index: the page index |
| 1746 | * @filler: function to perform the read |
| 1747 | * @data: destination for read data |
| 1748 | * |
Nick Piggin | 6fe6900 | 2007-05-06 14:49:04 -0700 | [diff] [blame] | 1749 | * Same as read_cache_page, but don't wait for page to become unlocked |
| 1750 | * after submitting it to the filler. |
Randy Dunlap | 7682486 | 2008-03-19 17:00:40 -0700 | [diff] [blame] | 1751 | * |
| 1752 | * Read into the page cache. If a page already exists, and PageUptodate() is |
| 1753 | * not set, try to fill the page but don't wait for it to become unlocked. |
| 1754 | * |
| 1755 | * If the page does not get brought uptodate, return -EIO. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1756 | */ |
Nick Piggin | 6fe6900 | 2007-05-06 14:49:04 -0700 | [diff] [blame] | 1757 | struct page *read_cache_page_async(struct address_space *mapping, |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 1758 | pgoff_t index, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1759 | int (*filler)(void *,struct page*), |
| 1760 | void *data) |
| 1761 | { |
| 1762 | struct page *page; |
| 1763 | int err; |
| 1764 | |
| 1765 | retry: |
| 1766 | page = __read_cache_page(mapping, index, filler, data); |
| 1767 | if (IS_ERR(page)) |
David Howells | c855ff3 | 2007-05-09 13:42:20 +0100 | [diff] [blame] | 1768 | return page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1769 | if (PageUptodate(page)) |
| 1770 | goto out; |
| 1771 | |
| 1772 | lock_page(page); |
| 1773 | if (!page->mapping) { |
| 1774 | unlock_page(page); |
| 1775 | page_cache_release(page); |
| 1776 | goto retry; |
| 1777 | } |
| 1778 | if (PageUptodate(page)) { |
| 1779 | unlock_page(page); |
| 1780 | goto out; |
| 1781 | } |
| 1782 | err = filler(data, page); |
| 1783 | if (err < 0) { |
| 1784 | page_cache_release(page); |
David Howells | c855ff3 | 2007-05-09 13:42:20 +0100 | [diff] [blame] | 1785 | return ERR_PTR(err); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1786 | } |
David Howells | c855ff3 | 2007-05-09 13:42:20 +0100 | [diff] [blame] | 1787 | out: |
Nick Piggin | 6fe6900 | 2007-05-06 14:49:04 -0700 | [diff] [blame] | 1788 | mark_page_accessed(page); |
| 1789 | return page; |
| 1790 | } |
| 1791 | EXPORT_SYMBOL(read_cache_page_async); |
| 1792 | |
| 1793 | /** |
| 1794 | * read_cache_page - read into page cache, fill it if needed |
| 1795 | * @mapping: the page's address_space |
| 1796 | * @index: the page index |
| 1797 | * @filler: function to perform the read |
| 1798 | * @data: destination for read data |
| 1799 | * |
| 1800 | * Read into the page cache. If a page already exists, and PageUptodate() is |
| 1801 | * not set, try to fill the page then wait for it to become unlocked. |
| 1802 | * |
| 1803 | * If the page does not get brought uptodate, return -EIO. |
| 1804 | */ |
| 1805 | struct page *read_cache_page(struct address_space *mapping, |
Fengguang Wu | 57f6b96 | 2007-10-16 01:24:37 -0700 | [diff] [blame] | 1806 | pgoff_t index, |
Nick Piggin | 6fe6900 | 2007-05-06 14:49:04 -0700 | [diff] [blame] | 1807 | int (*filler)(void *,struct page*), |
| 1808 | void *data) |
| 1809 | { |
| 1810 | struct page *page; |
| 1811 | |
| 1812 | page = read_cache_page_async(mapping, index, filler, data); |
| 1813 | if (IS_ERR(page)) |
| 1814 | goto out; |
| 1815 | wait_on_page_locked(page); |
| 1816 | if (!PageUptodate(page)) { |
| 1817 | page_cache_release(page); |
| 1818 | page = ERR_PTR(-EIO); |
| 1819 | } |
| 1820 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1821 | return page; |
| 1822 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1823 | EXPORT_SYMBOL(read_cache_page); |
| 1824 | |
| 1825 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1826 | * The logic we want is |
| 1827 | * |
| 1828 | * if suid or (sgid and xgrp) |
| 1829 | * remove privs |
| 1830 | */ |
Jens Axboe | 01de85e | 2006-10-17 19:50:36 +0200 | [diff] [blame] | 1831 | int should_remove_suid(struct dentry *dentry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1832 | { |
| 1833 | mode_t mode = dentry->d_inode->i_mode; |
| 1834 | int kill = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1835 | |
| 1836 | /* suid always must be killed */ |
| 1837 | if (unlikely(mode & S_ISUID)) |
| 1838 | kill = ATTR_KILL_SUID; |
| 1839 | |
| 1840 | /* |
| 1841 | * sgid without any exec bits is just a mandatory locking mark; leave |
| 1842 | * it alone. If some exec bits are set, it's a real sgid; kill it. |
| 1843 | */ |
| 1844 | if (unlikely((mode & S_ISGID) && (mode & S_IXGRP))) |
| 1845 | kill |= ATTR_KILL_SGID; |
| 1846 | |
Dmitri Monakhov | 7f5ff76 | 2008-12-01 14:34:56 -0800 | [diff] [blame] | 1847 | if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode))) |
Jens Axboe | 01de85e | 2006-10-17 19:50:36 +0200 | [diff] [blame] | 1848 | return kill; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1849 | |
Jens Axboe | 01de85e | 2006-10-17 19:50:36 +0200 | [diff] [blame] | 1850 | return 0; |
| 1851 | } |
Mark Fasheh | d23a147 | 2006-10-17 17:05:18 -0700 | [diff] [blame] | 1852 | EXPORT_SYMBOL(should_remove_suid); |
Jens Axboe | 01de85e | 2006-10-17 19:50:36 +0200 | [diff] [blame] | 1853 | |
Miklos Szeredi | 7f3d4ee | 2008-05-07 09:22:39 +0200 | [diff] [blame] | 1854 | static int __remove_suid(struct dentry *dentry, int kill) |
Jens Axboe | 01de85e | 2006-10-17 19:50:36 +0200 | [diff] [blame] | 1855 | { |
| 1856 | struct iattr newattrs; |
| 1857 | |
| 1858 | newattrs.ia_valid = ATTR_FORCE | kill; |
| 1859 | return notify_change(dentry, &newattrs); |
| 1860 | } |
| 1861 | |
Miklos Szeredi | 2f1936b | 2008-06-24 16:50:14 +0200 | [diff] [blame] | 1862 | int file_remove_suid(struct file *file) |
Jens Axboe | 01de85e | 2006-10-17 19:50:36 +0200 | [diff] [blame] | 1863 | { |
Miklos Szeredi | 2f1936b | 2008-06-24 16:50:14 +0200 | [diff] [blame] | 1864 | struct dentry *dentry = file->f_path.dentry; |
Serge E. Hallyn | b537677 | 2007-10-16 23:31:36 -0700 | [diff] [blame] | 1865 | int killsuid = should_remove_suid(dentry); |
| 1866 | int killpriv = security_inode_need_killpriv(dentry); |
| 1867 | int error = 0; |
Jens Axboe | 01de85e | 2006-10-17 19:50:36 +0200 | [diff] [blame] | 1868 | |
Serge E. Hallyn | b537677 | 2007-10-16 23:31:36 -0700 | [diff] [blame] | 1869 | if (killpriv < 0) |
| 1870 | return killpriv; |
| 1871 | if (killpriv) |
| 1872 | error = security_inode_killpriv(dentry); |
| 1873 | if (!error && killsuid) |
| 1874 | error = __remove_suid(dentry, killsuid); |
Jens Axboe | 01de85e | 2006-10-17 19:50:36 +0200 | [diff] [blame] | 1875 | |
Serge E. Hallyn | b537677 | 2007-10-16 23:31:36 -0700 | [diff] [blame] | 1876 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1877 | } |
Miklos Szeredi | 2f1936b | 2008-06-24 16:50:14 +0200 | [diff] [blame] | 1878 | EXPORT_SYMBOL(file_remove_suid); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1879 | |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1880 | static size_t __iovec_copy_from_user_inatomic(char *vaddr, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1881 | const struct iovec *iov, size_t base, size_t bytes) |
| 1882 | { |
Ingo Molnar | f180053 | 2009-03-02 11:00:57 +0100 | [diff] [blame] | 1883 | size_t copied = 0, left = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1884 | |
| 1885 | while (bytes) { |
| 1886 | char __user *buf = iov->iov_base + base; |
| 1887 | int copy = min(bytes, iov->iov_len - base); |
| 1888 | |
| 1889 | base = 0; |
Ingo Molnar | f180053 | 2009-03-02 11:00:57 +0100 | [diff] [blame] | 1890 | left = __copy_from_user_inatomic(vaddr, buf, copy); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1891 | copied += copy; |
| 1892 | bytes -= copy; |
| 1893 | vaddr += copy; |
| 1894 | iov++; |
| 1895 | |
NeilBrown | 01408c4 | 2006-06-25 05:47:58 -0700 | [diff] [blame] | 1896 | if (unlikely(left)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1897 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1898 | } |
| 1899 | return copied - left; |
| 1900 | } |
| 1901 | |
| 1902 | /* |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1903 | * Copy as much as we can into the page and return the number of bytes which |
| 1904 | * were sucessfully copied. If a fault is encountered then return the number of |
| 1905 | * bytes which were copied. |
| 1906 | */ |
| 1907 | size_t iov_iter_copy_from_user_atomic(struct page *page, |
| 1908 | struct iov_iter *i, unsigned long offset, size_t bytes) |
| 1909 | { |
| 1910 | char *kaddr; |
| 1911 | size_t copied; |
| 1912 | |
| 1913 | BUG_ON(!in_atomic()); |
| 1914 | kaddr = kmap_atomic(page, KM_USER0); |
| 1915 | if (likely(i->nr_segs == 1)) { |
| 1916 | int left; |
| 1917 | char __user *buf = i->iov->iov_base + i->iov_offset; |
Ingo Molnar | f180053 | 2009-03-02 11:00:57 +0100 | [diff] [blame] | 1918 | left = __copy_from_user_inatomic(kaddr + offset, buf, bytes); |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1919 | copied = bytes - left; |
| 1920 | } else { |
| 1921 | copied = __iovec_copy_from_user_inatomic(kaddr + offset, |
| 1922 | i->iov, i->iov_offset, bytes); |
| 1923 | } |
| 1924 | kunmap_atomic(kaddr, KM_USER0); |
| 1925 | |
| 1926 | return copied; |
| 1927 | } |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 1928 | EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1929 | |
| 1930 | /* |
| 1931 | * This has the same sideeffects and return value as |
| 1932 | * iov_iter_copy_from_user_atomic(). |
| 1933 | * The difference is that it attempts to resolve faults. |
| 1934 | * Page must not be locked. |
| 1935 | */ |
| 1936 | size_t iov_iter_copy_from_user(struct page *page, |
| 1937 | struct iov_iter *i, unsigned long offset, size_t bytes) |
| 1938 | { |
| 1939 | char *kaddr; |
| 1940 | size_t copied; |
| 1941 | |
| 1942 | kaddr = kmap(page); |
| 1943 | if (likely(i->nr_segs == 1)) { |
| 1944 | int left; |
| 1945 | char __user *buf = i->iov->iov_base + i->iov_offset; |
Ingo Molnar | f180053 | 2009-03-02 11:00:57 +0100 | [diff] [blame] | 1946 | left = __copy_from_user(kaddr + offset, buf, bytes); |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1947 | copied = bytes - left; |
| 1948 | } else { |
| 1949 | copied = __iovec_copy_from_user_inatomic(kaddr + offset, |
| 1950 | i->iov, i->iov_offset, bytes); |
| 1951 | } |
| 1952 | kunmap(page); |
| 1953 | return copied; |
| 1954 | } |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 1955 | EXPORT_SYMBOL(iov_iter_copy_from_user); |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1956 | |
Nick Piggin | f700926 | 2008-03-10 11:43:59 -0700 | [diff] [blame] | 1957 | void iov_iter_advance(struct iov_iter *i, size_t bytes) |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1958 | { |
Nick Piggin | f700926 | 2008-03-10 11:43:59 -0700 | [diff] [blame] | 1959 | BUG_ON(i->count < bytes); |
| 1960 | |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1961 | if (likely(i->nr_segs == 1)) { |
| 1962 | i->iov_offset += bytes; |
Nick Piggin | f700926 | 2008-03-10 11:43:59 -0700 | [diff] [blame] | 1963 | i->count -= bytes; |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1964 | } else { |
| 1965 | const struct iovec *iov = i->iov; |
| 1966 | size_t base = i->iov_offset; |
| 1967 | |
Nick Piggin | 124d3b7 | 2008-02-02 15:01:17 +0100 | [diff] [blame] | 1968 | /* |
| 1969 | * The !iov->iov_len check ensures we skip over unlikely |
Nick Piggin | f700926 | 2008-03-10 11:43:59 -0700 | [diff] [blame] | 1970 | * zero-length segments (without overruning the iovec). |
Nick Piggin | 124d3b7 | 2008-02-02 15:01:17 +0100 | [diff] [blame] | 1971 | */ |
Linus Torvalds | 94ad374 | 2008-07-30 14:45:12 -0700 | [diff] [blame] | 1972 | while (bytes || unlikely(i->count && !iov->iov_len)) { |
Nick Piggin | f700926 | 2008-03-10 11:43:59 -0700 | [diff] [blame] | 1973 | int copy; |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1974 | |
Nick Piggin | f700926 | 2008-03-10 11:43:59 -0700 | [diff] [blame] | 1975 | copy = min(bytes, iov->iov_len - base); |
| 1976 | BUG_ON(!i->count || i->count < copy); |
| 1977 | i->count -= copy; |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1978 | bytes -= copy; |
| 1979 | base += copy; |
| 1980 | if (iov->iov_len == base) { |
| 1981 | iov++; |
| 1982 | base = 0; |
| 1983 | } |
| 1984 | } |
| 1985 | i->iov = iov; |
| 1986 | i->iov_offset = base; |
| 1987 | } |
| 1988 | } |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 1989 | EXPORT_SYMBOL(iov_iter_advance); |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 1990 | |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1991 | /* |
| 1992 | * Fault in the first iovec of the given iov_iter, to a maximum length |
| 1993 | * of bytes. Returns 0 on success, or non-zero if the memory could not be |
| 1994 | * accessed (ie. because it is an invalid address). |
| 1995 | * |
| 1996 | * writev-intensive code may want this to prefault several iovecs -- that |
| 1997 | * would be possible (callers must not rely on the fact that _only_ the |
| 1998 | * first iovec will be faulted with the current implementation). |
| 1999 | */ |
| 2000 | 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] | 2001 | { |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2002 | char __user *buf = i->iov->iov_base + i->iov_offset; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2003 | bytes = min(bytes, i->iov->iov_len - i->iov_offset); |
| 2004 | return fault_in_pages_readable(buf, bytes); |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2005 | } |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2006 | EXPORT_SYMBOL(iov_iter_fault_in_readable); |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2007 | |
| 2008 | /* |
| 2009 | * Return the count of just the current iov_iter segment. |
| 2010 | */ |
| 2011 | size_t iov_iter_single_seg_count(struct iov_iter *i) |
| 2012 | { |
| 2013 | const struct iovec *iov = i->iov; |
| 2014 | if (i->nr_segs == 1) |
| 2015 | return i->count; |
| 2016 | else |
| 2017 | return min(i->count, iov->iov_len - i->iov_offset); |
| 2018 | } |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2019 | EXPORT_SYMBOL(iov_iter_single_seg_count); |
Nick Piggin | 2f718ff | 2007-10-16 01:24:59 -0700 | [diff] [blame] | 2020 | |
| 2021 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2022 | * Performs necessary checks before doing a write |
| 2023 | * |
Randy Dunlap | 485bb99 | 2006-06-23 02:03:49 -0700 | [diff] [blame] | 2024 | * Can adjust writing position or amount of bytes to write. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2025 | * Returns appropriate error code that caller should return or |
| 2026 | * zero in case that write should be allowed. |
| 2027 | */ |
| 2028 | inline int generic_write_checks(struct file *file, loff_t *pos, size_t *count, int isblk) |
| 2029 | { |
| 2030 | struct inode *inode = file->f_mapping->host; |
| 2031 | unsigned long limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; |
| 2032 | |
| 2033 | if (unlikely(*pos < 0)) |
| 2034 | return -EINVAL; |
| 2035 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2036 | if (!isblk) { |
| 2037 | /* FIXME: this is for backwards compatibility with 2.4 */ |
| 2038 | if (file->f_flags & O_APPEND) |
| 2039 | *pos = i_size_read(inode); |
| 2040 | |
| 2041 | if (limit != RLIM_INFINITY) { |
| 2042 | if (*pos >= limit) { |
| 2043 | send_sig(SIGXFSZ, current, 0); |
| 2044 | return -EFBIG; |
| 2045 | } |
| 2046 | if (*count > limit - (typeof(limit))*pos) { |
| 2047 | *count = limit - (typeof(limit))*pos; |
| 2048 | } |
| 2049 | } |
| 2050 | } |
| 2051 | |
| 2052 | /* |
| 2053 | * LFS rule |
| 2054 | */ |
| 2055 | if (unlikely(*pos + *count > MAX_NON_LFS && |
| 2056 | !(file->f_flags & O_LARGEFILE))) { |
| 2057 | if (*pos >= MAX_NON_LFS) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2058 | return -EFBIG; |
| 2059 | } |
| 2060 | if (*count > MAX_NON_LFS - (unsigned long)*pos) { |
| 2061 | *count = MAX_NON_LFS - (unsigned long)*pos; |
| 2062 | } |
| 2063 | } |
| 2064 | |
| 2065 | /* |
| 2066 | * Are we about to exceed the fs block limit ? |
| 2067 | * |
| 2068 | * If we have written data it becomes a short write. If we have |
| 2069 | * exceeded without writing data we send a signal and return EFBIG. |
| 2070 | * Linus frestrict idea will clean these up nicely.. |
| 2071 | */ |
| 2072 | if (likely(!isblk)) { |
| 2073 | if (unlikely(*pos >= inode->i_sb->s_maxbytes)) { |
| 2074 | if (*count || *pos > inode->i_sb->s_maxbytes) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2075 | return -EFBIG; |
| 2076 | } |
| 2077 | /* zero-length writes at ->s_maxbytes are OK */ |
| 2078 | } |
| 2079 | |
| 2080 | if (unlikely(*pos + *count > inode->i_sb->s_maxbytes)) |
| 2081 | *count = inode->i_sb->s_maxbytes - *pos; |
| 2082 | } else { |
David Howells | 9361401 | 2006-09-30 20:45:40 +0200 | [diff] [blame] | 2083 | #ifdef CONFIG_BLOCK |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2084 | loff_t isize; |
| 2085 | if (bdev_read_only(I_BDEV(inode))) |
| 2086 | return -EPERM; |
| 2087 | isize = i_size_read(inode); |
| 2088 | if (*pos >= isize) { |
| 2089 | if (*count || *pos > isize) |
| 2090 | return -ENOSPC; |
| 2091 | } |
| 2092 | |
| 2093 | if (*pos + *count > isize) |
| 2094 | *count = isize - *pos; |
David Howells | 9361401 | 2006-09-30 20:45:40 +0200 | [diff] [blame] | 2095 | #else |
| 2096 | return -EPERM; |
| 2097 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2098 | } |
| 2099 | return 0; |
| 2100 | } |
| 2101 | EXPORT_SYMBOL(generic_write_checks); |
| 2102 | |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2103 | int pagecache_write_begin(struct file *file, struct address_space *mapping, |
| 2104 | loff_t pos, unsigned len, unsigned flags, |
| 2105 | struct page **pagep, void **fsdata) |
| 2106 | { |
| 2107 | const struct address_space_operations *aops = mapping->a_ops; |
| 2108 | |
Nick Piggin | 4e02ed4 | 2008-10-29 14:00:55 -0700 | [diff] [blame] | 2109 | return aops->write_begin(file, mapping, pos, len, flags, |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2110 | pagep, fsdata); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2111 | } |
| 2112 | EXPORT_SYMBOL(pagecache_write_begin); |
| 2113 | |
| 2114 | int pagecache_write_end(struct file *file, struct address_space *mapping, |
| 2115 | loff_t pos, unsigned len, unsigned copied, |
| 2116 | struct page *page, void *fsdata) |
| 2117 | { |
| 2118 | const struct address_space_operations *aops = mapping->a_ops; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2119 | |
Nick Piggin | 4e02ed4 | 2008-10-29 14:00:55 -0700 | [diff] [blame] | 2120 | mark_page_accessed(page); |
| 2121 | return aops->write_end(file, mapping, pos, len, copied, page, fsdata); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2122 | } |
| 2123 | EXPORT_SYMBOL(pagecache_write_end); |
| 2124 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2125 | ssize_t |
| 2126 | generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov, |
| 2127 | unsigned long *nr_segs, loff_t pos, loff_t *ppos, |
| 2128 | size_t count, size_t ocount) |
| 2129 | { |
| 2130 | struct file *file = iocb->ki_filp; |
| 2131 | struct address_space *mapping = file->f_mapping; |
| 2132 | struct inode *inode = mapping->host; |
| 2133 | ssize_t written; |
Christoph Hellwig | a969e90 | 2008-07-23 21:27:04 -0700 | [diff] [blame] | 2134 | size_t write_len; |
| 2135 | pgoff_t end; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2136 | |
| 2137 | if (count != ocount) |
| 2138 | *nr_segs = iov_shorten((struct iovec *)iov, *nr_segs, count); |
| 2139 | |
Christoph Hellwig | a969e90 | 2008-07-23 21:27:04 -0700 | [diff] [blame] | 2140 | write_len = iov_length(iov, *nr_segs); |
| 2141 | end = (pos + write_len - 1) >> PAGE_CACHE_SHIFT; |
Christoph Hellwig | a969e90 | 2008-07-23 21:27:04 -0700 | [diff] [blame] | 2142 | |
Nick Piggin | 48b47c5 | 2009-01-06 14:40:22 -0800 | [diff] [blame] | 2143 | written = filemap_write_and_wait_range(mapping, pos, pos + write_len - 1); |
Christoph Hellwig | a969e90 | 2008-07-23 21:27:04 -0700 | [diff] [blame] | 2144 | if (written) |
| 2145 | goto out; |
| 2146 | |
| 2147 | /* |
| 2148 | * After a write we want buffered reads to be sure to go to disk to get |
| 2149 | * the new data. We invalidate clean cached page from the region we're |
| 2150 | * about to write. We do this *before* the write so that we can return |
Hisashi Hifumi | 6ccfa80 | 2008-09-02 14:35:40 -0700 | [diff] [blame] | 2151 | * without clobbering -EIOCBQUEUED from ->direct_IO(). |
Christoph Hellwig | a969e90 | 2008-07-23 21:27:04 -0700 | [diff] [blame] | 2152 | */ |
| 2153 | if (mapping->nrpages) { |
| 2154 | written = invalidate_inode_pages2_range(mapping, |
| 2155 | pos >> PAGE_CACHE_SHIFT, end); |
Hisashi Hifumi | 6ccfa80 | 2008-09-02 14:35:40 -0700 | [diff] [blame] | 2156 | /* |
| 2157 | * If a page can not be invalidated, return 0 to fall back |
| 2158 | * to buffered write. |
| 2159 | */ |
| 2160 | if (written) { |
| 2161 | if (written == -EBUSY) |
| 2162 | return 0; |
Christoph Hellwig | a969e90 | 2008-07-23 21:27:04 -0700 | [diff] [blame] | 2163 | goto out; |
Hisashi Hifumi | 6ccfa80 | 2008-09-02 14:35:40 -0700 | [diff] [blame] | 2164 | } |
Christoph Hellwig | a969e90 | 2008-07-23 21:27:04 -0700 | [diff] [blame] | 2165 | } |
| 2166 | |
| 2167 | written = mapping->a_ops->direct_IO(WRITE, iocb, iov, pos, *nr_segs); |
| 2168 | |
| 2169 | /* |
| 2170 | * Finally, try again to invalidate clean pages which might have been |
| 2171 | * cached by non-direct readahead, or faulted in by get_user_pages() |
| 2172 | * if the source of the write was an mmap'ed region of the file |
| 2173 | * we're writing. Either one is a pretty crazy thing to do, |
| 2174 | * so we don't support it 100%. If this invalidation |
| 2175 | * fails, tough, the write still worked... |
| 2176 | */ |
| 2177 | if (mapping->nrpages) { |
| 2178 | invalidate_inode_pages2_range(mapping, |
| 2179 | pos >> PAGE_CACHE_SHIFT, end); |
| 2180 | } |
| 2181 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2182 | if (written > 0) { |
| 2183 | loff_t end = pos + written; |
| 2184 | if (end > i_size_read(inode) && !S_ISBLK(inode->i_mode)) { |
| 2185 | i_size_write(inode, end); |
| 2186 | mark_inode_dirty(inode); |
| 2187 | } |
| 2188 | *ppos = end; |
| 2189 | } |
| 2190 | |
| 2191 | /* |
| 2192 | * Sync the fs metadata but not the minor inode changes and |
| 2193 | * 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] | 2194 | * i_mutex is held, which protects generic_osync_inode() from |
Zach Brown | 8459d86 | 2006-12-10 02:21:05 -0800 | [diff] [blame] | 2195 | * livelocking. AIO O_DIRECT ops attempt to sync metadata here. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2196 | */ |
Christoph Hellwig | a969e90 | 2008-07-23 21:27:04 -0700 | [diff] [blame] | 2197 | out: |
Zach Brown | 8459d86 | 2006-12-10 02:21:05 -0800 | [diff] [blame] | 2198 | if ((written >= 0 || written == -EIOCBQUEUED) && |
| 2199 | ((file->f_flags & O_SYNC) || IS_SYNC(inode))) { |
Hifumi Hisashi | 1e8a81c | 2005-06-25 14:54:32 -0700 | [diff] [blame] | 2200 | int err = generic_osync_inode(inode, mapping, OSYNC_METADATA); |
| 2201 | if (err < 0) |
| 2202 | written = err; |
| 2203 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2204 | return written; |
| 2205 | } |
| 2206 | EXPORT_SYMBOL(generic_file_direct_write); |
| 2207 | |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 2208 | /* |
| 2209 | * Find or create a page at the given pagecache position. Return the locked |
| 2210 | * page. This function is specifically for buffered writes. |
| 2211 | */ |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 2212 | struct page *grab_cache_page_write_begin(struct address_space *mapping, |
| 2213 | pgoff_t index, unsigned flags) |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 2214 | { |
| 2215 | int status; |
| 2216 | struct page *page; |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 2217 | gfp_t gfp_notmask = 0; |
| 2218 | if (flags & AOP_FLAG_NOFS) |
| 2219 | gfp_notmask = __GFP_FS; |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 2220 | repeat: |
| 2221 | page = find_lock_page(mapping, index); |
| 2222 | if (likely(page)) |
| 2223 | return page; |
| 2224 | |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 2225 | page = __page_cache_alloc(mapping_gfp_mask(mapping) & ~gfp_notmask); |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 2226 | if (!page) |
| 2227 | return NULL; |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 2228 | status = add_to_page_cache_lru(page, mapping, index, |
| 2229 | GFP_KERNEL & ~gfp_notmask); |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 2230 | if (unlikely(status)) { |
| 2231 | page_cache_release(page); |
| 2232 | if (status == -EEXIST) |
| 2233 | goto repeat; |
| 2234 | return NULL; |
| 2235 | } |
| 2236 | return page; |
| 2237 | } |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 2238 | EXPORT_SYMBOL(grab_cache_page_write_begin); |
Nick Piggin | eb2be18 | 2007-10-16 01:24:57 -0700 | [diff] [blame] | 2239 | |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2240 | static ssize_t generic_perform_write(struct file *file, |
| 2241 | struct iov_iter *i, loff_t pos) |
| 2242 | { |
| 2243 | struct address_space *mapping = file->f_mapping; |
| 2244 | const struct address_space_operations *a_ops = mapping->a_ops; |
| 2245 | long status = 0; |
| 2246 | ssize_t written = 0; |
Nick Piggin | 674b892 | 2007-10-16 01:25:03 -0700 | [diff] [blame] | 2247 | unsigned int flags = 0; |
| 2248 | |
| 2249 | /* |
| 2250 | * Copies from kernel address space cannot fail (NFSD is a big user). |
| 2251 | */ |
| 2252 | if (segment_eq(get_fs(), KERNEL_DS)) |
| 2253 | flags |= AOP_FLAG_UNINTERRUPTIBLE; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2254 | |
| 2255 | do { |
| 2256 | struct page *page; |
| 2257 | pgoff_t index; /* Pagecache index for current page */ |
| 2258 | unsigned long offset; /* Offset into pagecache page */ |
| 2259 | unsigned long bytes; /* Bytes to write to page */ |
| 2260 | size_t copied; /* Bytes copied from user */ |
| 2261 | void *fsdata; |
| 2262 | |
| 2263 | offset = (pos & (PAGE_CACHE_SIZE - 1)); |
| 2264 | index = pos >> PAGE_CACHE_SHIFT; |
| 2265 | bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset, |
| 2266 | iov_iter_count(i)); |
| 2267 | |
| 2268 | again: |
| 2269 | |
| 2270 | /* |
| 2271 | * Bring in the user page that we will copy from _first_. |
| 2272 | * Otherwise there's a nasty deadlock on copying from the |
| 2273 | * same page as we're writing to, without it being marked |
| 2274 | * up-to-date. |
| 2275 | * |
| 2276 | * Not only is this an optimisation, but it is also required |
| 2277 | * to check that the address is actually valid, when atomic |
| 2278 | * usercopies are used, below. |
| 2279 | */ |
| 2280 | if (unlikely(iov_iter_fault_in_readable(i, bytes))) { |
| 2281 | status = -EFAULT; |
| 2282 | break; |
| 2283 | } |
| 2284 | |
Nick Piggin | 674b892 | 2007-10-16 01:25:03 -0700 | [diff] [blame] | 2285 | status = a_ops->write_begin(file, mapping, pos, bytes, flags, |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2286 | &page, &fsdata); |
| 2287 | if (unlikely(status)) |
| 2288 | break; |
| 2289 | |
| 2290 | pagefault_disable(); |
| 2291 | copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes); |
| 2292 | pagefault_enable(); |
| 2293 | flush_dcache_page(page); |
| 2294 | |
Josef Bacik | c8236db | 2009-07-05 12:08:18 -0700 | [diff] [blame] | 2295 | mark_page_accessed(page); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2296 | status = a_ops->write_end(file, mapping, pos, bytes, copied, |
| 2297 | page, fsdata); |
| 2298 | if (unlikely(status < 0)) |
| 2299 | break; |
| 2300 | copied = status; |
| 2301 | |
| 2302 | cond_resched(); |
| 2303 | |
Nick Piggin | 124d3b7 | 2008-02-02 15:01:17 +0100 | [diff] [blame] | 2304 | iov_iter_advance(i, copied); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2305 | if (unlikely(copied == 0)) { |
| 2306 | /* |
| 2307 | * If we were unable to copy any data at all, we must |
| 2308 | * fall back to a single segment length write. |
| 2309 | * |
| 2310 | * If we didn't fallback here, we could livelock |
| 2311 | * because not all segments in the iov can be copied at |
| 2312 | * once without a pagefault. |
| 2313 | */ |
| 2314 | bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset, |
| 2315 | iov_iter_single_seg_count(i)); |
| 2316 | goto again; |
| 2317 | } |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2318 | pos += copied; |
| 2319 | written += copied; |
| 2320 | |
| 2321 | balance_dirty_pages_ratelimited(mapping); |
| 2322 | |
| 2323 | } while (iov_iter_count(i)); |
| 2324 | |
| 2325 | return written ? written : status; |
| 2326 | } |
| 2327 | |
| 2328 | ssize_t |
| 2329 | generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov, |
| 2330 | unsigned long nr_segs, loff_t pos, loff_t *ppos, |
| 2331 | size_t count, ssize_t written) |
| 2332 | { |
| 2333 | struct file *file = iocb->ki_filp; |
| 2334 | struct address_space *mapping = file->f_mapping; |
| 2335 | const struct address_space_operations *a_ops = mapping->a_ops; |
| 2336 | struct inode *inode = mapping->host; |
| 2337 | ssize_t status; |
| 2338 | struct iov_iter i; |
| 2339 | |
| 2340 | iov_iter_init(&i, iov, nr_segs, count, written); |
Nick Piggin | 4e02ed4 | 2008-10-29 14:00:55 -0700 | [diff] [blame] | 2341 | status = generic_perform_write(file, &i, pos); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2342 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2343 | if (likely(status >= 0)) { |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2344 | written += status; |
| 2345 | *ppos = pos + status; |
| 2346 | |
| 2347 | /* |
| 2348 | * For now, when the user asks for O_SYNC, we'll actually give |
| 2349 | * O_DSYNC |
| 2350 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2351 | if (unlikely((file->f_flags & O_SYNC) || IS_SYNC(inode))) { |
| 2352 | if (!a_ops->writepage || !is_sync_kiocb(iocb)) |
| 2353 | status = generic_osync_inode(inode, mapping, |
| 2354 | OSYNC_METADATA|OSYNC_DATA); |
| 2355 | } |
| 2356 | } |
| 2357 | |
| 2358 | /* |
| 2359 | * If we get here for O_DIRECT writes then we must have fallen through |
| 2360 | * to buffered writes (block instantiation inside i_size). So we sync |
| 2361 | * the file data here, to try to honour O_DIRECT expectations. |
| 2362 | */ |
| 2363 | if (unlikely(file->f_flags & O_DIRECT) && written) |
Nick Piggin | 48b47c5 | 2009-01-06 14:40:22 -0800 | [diff] [blame] | 2364 | status = filemap_write_and_wait_range(mapping, |
| 2365 | pos, pos + written - 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2366 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2367 | return written ? written : status; |
| 2368 | } |
| 2369 | EXPORT_SYMBOL(generic_file_buffered_write); |
| 2370 | |
Adrian Bunk | 5ce7852 | 2005-09-10 00:26:28 -0700 | [diff] [blame] | 2371 | static ssize_t |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2372 | __generic_file_aio_write_nolock(struct kiocb *iocb, const struct iovec *iov, |
| 2373 | unsigned long nr_segs, loff_t *ppos) |
| 2374 | { |
| 2375 | struct file *file = iocb->ki_filp; |
Jeff Moyer | fb5527e | 2006-10-19 23:28:13 -0700 | [diff] [blame] | 2376 | struct address_space * mapping = file->f_mapping; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2377 | size_t ocount; /* original count */ |
| 2378 | size_t count; /* after file limit checks */ |
| 2379 | struct inode *inode = mapping->host; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2380 | loff_t pos; |
| 2381 | ssize_t written; |
| 2382 | ssize_t err; |
| 2383 | |
| 2384 | ocount = 0; |
Dmitriy Monakhov | 0ceb331 | 2007-05-08 00:23:02 -0700 | [diff] [blame] | 2385 | err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ); |
| 2386 | if (err) |
| 2387 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2388 | |
| 2389 | count = ocount; |
| 2390 | pos = *ppos; |
| 2391 | |
| 2392 | vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE); |
| 2393 | |
| 2394 | /* We can write back this queue in page reclaim */ |
| 2395 | current->backing_dev_info = mapping->backing_dev_info; |
| 2396 | written = 0; |
| 2397 | |
| 2398 | err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode)); |
| 2399 | if (err) |
| 2400 | goto out; |
| 2401 | |
| 2402 | if (count == 0) |
| 2403 | goto out; |
| 2404 | |
Miklos Szeredi | 2f1936b | 2008-06-24 16:50:14 +0200 | [diff] [blame] | 2405 | err = file_remove_suid(file); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2406 | if (err) |
| 2407 | goto out; |
| 2408 | |
Christoph Hellwig | 870f481 | 2006-01-09 20:52:01 -0800 | [diff] [blame] | 2409 | file_update_time(file); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2410 | |
| 2411 | /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */ |
| 2412 | if (unlikely(file->f_flags & O_DIRECT)) { |
Jeff Moyer | fb5527e | 2006-10-19 23:28:13 -0700 | [diff] [blame] | 2413 | loff_t endbyte; |
| 2414 | ssize_t written_buffered; |
| 2415 | |
| 2416 | written = generic_file_direct_write(iocb, iov, &nr_segs, pos, |
| 2417 | ppos, count, ocount); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2418 | if (written < 0 || written == count) |
| 2419 | goto out; |
| 2420 | /* |
| 2421 | * direct-io write to a hole: fall through to buffered I/O |
| 2422 | * for completing the rest of the request. |
| 2423 | */ |
| 2424 | pos += written; |
| 2425 | count -= written; |
Jeff Moyer | fb5527e | 2006-10-19 23:28:13 -0700 | [diff] [blame] | 2426 | written_buffered = generic_file_buffered_write(iocb, iov, |
| 2427 | nr_segs, pos, ppos, count, |
| 2428 | written); |
| 2429 | /* |
| 2430 | * If generic_file_buffered_write() retuned a synchronous error |
| 2431 | * then we want to return the number of bytes which were |
| 2432 | * direct-written, or the error code if that was zero. Note |
| 2433 | * that this differs from normal direct-io semantics, which |
| 2434 | * will return -EFOO even if some bytes were written. |
| 2435 | */ |
| 2436 | if (written_buffered < 0) { |
| 2437 | err = written_buffered; |
| 2438 | goto out; |
| 2439 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2440 | |
Jeff Moyer | fb5527e | 2006-10-19 23:28:13 -0700 | [diff] [blame] | 2441 | /* |
| 2442 | * We need to ensure that the page cache pages are written to |
| 2443 | * disk and invalidated to preserve the expected O_DIRECT |
| 2444 | * semantics. |
| 2445 | */ |
| 2446 | endbyte = pos + written_buffered - written - 1; |
Mark Fasheh | ef51c97 | 2007-05-08 00:27:10 -0700 | [diff] [blame] | 2447 | err = do_sync_mapping_range(file->f_mapping, pos, endbyte, |
| 2448 | SYNC_FILE_RANGE_WAIT_BEFORE| |
| 2449 | SYNC_FILE_RANGE_WRITE| |
| 2450 | SYNC_FILE_RANGE_WAIT_AFTER); |
Jeff Moyer | fb5527e | 2006-10-19 23:28:13 -0700 | [diff] [blame] | 2451 | if (err == 0) { |
| 2452 | written = written_buffered; |
| 2453 | invalidate_mapping_pages(mapping, |
| 2454 | pos >> PAGE_CACHE_SHIFT, |
| 2455 | endbyte >> PAGE_CACHE_SHIFT); |
| 2456 | } else { |
| 2457 | /* |
| 2458 | * We don't know how much we wrote, so just return |
| 2459 | * the number of bytes which were direct-written |
| 2460 | */ |
| 2461 | } |
| 2462 | } else { |
| 2463 | written = generic_file_buffered_write(iocb, iov, nr_segs, |
| 2464 | pos, ppos, count, written); |
| 2465 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2466 | out: |
| 2467 | current->backing_dev_info = NULL; |
| 2468 | return written ? written : err; |
| 2469 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2470 | |
Badari Pulavarty | 027445c | 2006-09-30 23:28:46 -0700 | [diff] [blame] | 2471 | ssize_t generic_file_aio_write_nolock(struct kiocb *iocb, |
| 2472 | const struct iovec *iov, unsigned long nr_segs, loff_t pos) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2473 | { |
| 2474 | struct file *file = iocb->ki_filp; |
| 2475 | struct address_space *mapping = file->f_mapping; |
| 2476 | struct inode *inode = mapping->host; |
| 2477 | ssize_t ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2478 | |
Badari Pulavarty | 027445c | 2006-09-30 23:28:46 -0700 | [diff] [blame] | 2479 | BUG_ON(iocb->ki_pos != pos); |
| 2480 | |
| 2481 | ret = __generic_file_aio_write_nolock(iocb, iov, nr_segs, |
| 2482 | &iocb->ki_pos); |
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))) { |
Badari Pulavarty | 027445c | 2006-09-30 23:28:46 -0700 | [diff] [blame] | 2485 | ssize_t err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2486 | |
| 2487 | err = sync_page_range_nolock(inode, mapping, pos, ret); |
| 2488 | if (err < 0) |
| 2489 | ret = err; |
| 2490 | } |
| 2491 | return ret; |
| 2492 | } |
Badari Pulavarty | 027445c | 2006-09-30 23:28:46 -0700 | [diff] [blame] | 2493 | EXPORT_SYMBOL(generic_file_aio_write_nolock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2494 | |
Badari Pulavarty | 027445c | 2006-09-30 23:28:46 -0700 | [diff] [blame] | 2495 | ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov, |
| 2496 | unsigned long nr_segs, loff_t pos) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2497 | { |
| 2498 | struct file *file = iocb->ki_filp; |
| 2499 | struct address_space *mapping = file->f_mapping; |
| 2500 | struct inode *inode = mapping->host; |
| 2501 | ssize_t ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2502 | |
| 2503 | BUG_ON(iocb->ki_pos != pos); |
| 2504 | |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2505 | mutex_lock(&inode->i_mutex); |
Badari Pulavarty | 027445c | 2006-09-30 23:28:46 -0700 | [diff] [blame] | 2506 | ret = __generic_file_aio_write_nolock(iocb, iov, nr_segs, |
| 2507 | &iocb->ki_pos); |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2508 | mutex_unlock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2509 | |
| 2510 | if (ret > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) { |
| 2511 | ssize_t err; |
| 2512 | |
| 2513 | err = sync_page_range(inode, mapping, pos, ret); |
| 2514 | if (err < 0) |
| 2515 | ret = err; |
| 2516 | } |
| 2517 | return ret; |
| 2518 | } |
| 2519 | EXPORT_SYMBOL(generic_file_aio_write); |
| 2520 | |
David Howells | cf9a2ae | 2006-08-29 19:05:54 +0100 | [diff] [blame] | 2521 | /** |
| 2522 | * try_to_release_page() - release old fs-specific metadata on a page |
| 2523 | * |
| 2524 | * @page: the page which the kernel is trying to free |
| 2525 | * @gfp_mask: memory allocation flags (and I/O mode) |
| 2526 | * |
| 2527 | * The address_space is to try to release any data against the page |
| 2528 | * (presumably at page->private). If the release was successful, return `1'. |
| 2529 | * Otherwise return zero. |
| 2530 | * |
David Howells | 266cf65 | 2009-04-03 16:42:36 +0100 | [diff] [blame] | 2531 | * This may also be called if PG_fscache is set on a page, indicating that the |
| 2532 | * page is known to the local caching routines. |
| 2533 | * |
David Howells | cf9a2ae | 2006-08-29 19:05:54 +0100 | [diff] [blame] | 2534 | * The @gfp_mask argument specifies whether I/O may be performed to release |
Mingming Cao | 3f31fdd | 2008-07-25 01:46:22 -0700 | [diff] [blame] | 2535 | * this page (__GFP_IO), and whether the call may block (__GFP_WAIT & __GFP_FS). |
David Howells | cf9a2ae | 2006-08-29 19:05:54 +0100 | [diff] [blame] | 2536 | * |
David Howells | cf9a2ae | 2006-08-29 19:05:54 +0100 | [diff] [blame] | 2537 | */ |
| 2538 | int try_to_release_page(struct page *page, gfp_t gfp_mask) |
| 2539 | { |
| 2540 | struct address_space * const mapping = page->mapping; |
| 2541 | |
| 2542 | BUG_ON(!PageLocked(page)); |
| 2543 | if (PageWriteback(page)) |
| 2544 | return 0; |
| 2545 | |
| 2546 | if (mapping && mapping->a_ops->releasepage) |
| 2547 | return mapping->a_ops->releasepage(page, gfp_mask); |
| 2548 | return try_to_free_buffers(page); |
| 2549 | } |
| 2550 | |
| 2551 | EXPORT_SYMBOL(try_to_release_page); |