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39279cc3 CM |
1 | #include <linux/module.h> |
2 | #include <linux/buffer_head.h> | |
3 | #include <linux/fs.h> | |
4 | #include <linux/pagemap.h> | |
5 | #include <linux/highmem.h> | |
6 | #include <linux/time.h> | |
7 | #include <linux/init.h> | |
8 | #include <linux/string.h> | |
9 | #include <linux/smp_lock.h> | |
10 | #include <linux/backing-dev.h> | |
11 | #include <linux/mpage.h> | |
12 | #include <linux/swap.h> | |
13 | #include <linux/writeback.h> | |
14 | #include <linux/statfs.h> | |
15 | #include <linux/compat.h> | |
16 | #include "ctree.h" | |
17 | #include "disk-io.h" | |
18 | #include "transaction.h" | |
19 | #include "btrfs_inode.h" | |
20 | #include "ioctl.h" | |
21 | #include "print-tree.h" | |
22 | ||
23 | ||
24 | static int btrfs_copy_from_user(loff_t pos, int num_pages, int write_bytes, | |
25 | struct page **prepared_pages, | |
26 | const char __user * buf) | |
27 | { | |
28 | long page_fault = 0; | |
29 | int i; | |
30 | int offset = pos & (PAGE_CACHE_SIZE - 1); | |
31 | ||
32 | for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) { | |
33 | size_t count = min_t(size_t, | |
34 | PAGE_CACHE_SIZE - offset, write_bytes); | |
35 | struct page *page = prepared_pages[i]; | |
36 | fault_in_pages_readable(buf, count); | |
37 | ||
38 | /* Copy data from userspace to the current page */ | |
39 | kmap(page); | |
40 | page_fault = __copy_from_user(page_address(page) + offset, | |
41 | buf, count); | |
42 | /* Flush processor's dcache for this page */ | |
43 | flush_dcache_page(page); | |
44 | kunmap(page); | |
45 | buf += count; | |
46 | write_bytes -= count; | |
47 | ||
48 | if (page_fault) | |
49 | break; | |
50 | } | |
51 | return page_fault ? -EFAULT : 0; | |
52 | } | |
53 | ||
54 | static void btrfs_drop_pages(struct page **pages, size_t num_pages) | |
55 | { | |
56 | size_t i; | |
57 | for (i = 0; i < num_pages; i++) { | |
58 | if (!pages[i]) | |
59 | break; | |
60 | unlock_page(pages[i]); | |
61 | mark_page_accessed(pages[i]); | |
62 | page_cache_release(pages[i]); | |
63 | } | |
64 | } | |
65 | ||
66 | static int dirty_and_release_pages(struct btrfs_trans_handle *trans, | |
67 | struct btrfs_root *root, | |
68 | struct file *file, | |
69 | struct page **pages, | |
70 | size_t num_pages, | |
71 | loff_t pos, | |
72 | size_t write_bytes) | |
73 | { | |
74 | int i; | |
75 | int offset; | |
76 | int err = 0; | |
77 | int ret; | |
78 | int this_write; | |
79 | struct inode *inode = file->f_path.dentry->d_inode; | |
80 | struct buffer_head *bh; | |
81 | struct btrfs_file_extent_item *ei; | |
82 | ||
83 | for (i = 0; i < num_pages; i++) { | |
84 | offset = pos & (PAGE_CACHE_SIZE -1); | |
84f54cfa | 85 | this_write = min((size_t)PAGE_CACHE_SIZE - offset, write_bytes); |
39279cc3 CM |
86 | /* FIXME, one block at a time */ |
87 | ||
88 | mutex_lock(&root->fs_info->fs_mutex); | |
89 | trans = btrfs_start_transaction(root, 1); | |
90 | btrfs_set_trans_block_group(trans, inode); | |
91 | ||
92 | bh = page_buffers(pages[i]); | |
93 | ||
94 | if (buffer_mapped(bh) && bh->b_blocknr == 0) { | |
95 | struct btrfs_key key; | |
96 | struct btrfs_path *path; | |
97 | char *ptr; | |
98 | u32 datasize; | |
99 | ||
100 | /* create an inline extent, and copy the data in */ | |
101 | path = btrfs_alloc_path(); | |
102 | BUG_ON(!path); | |
103 | key.objectid = inode->i_ino; | |
104 | key.offset = pages[i]->index << PAGE_CACHE_SHIFT; | |
105 | key.flags = 0; | |
106 | btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY); | |
107 | BUG_ON(write_bytes >= PAGE_CACHE_SIZE); | |
108 | datasize = offset + | |
109 | btrfs_file_extent_calc_inline_size(write_bytes); | |
110 | ||
111 | ret = btrfs_insert_empty_item(trans, root, path, &key, | |
112 | datasize); | |
113 | BUG_ON(ret); | |
114 | ei = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), | |
115 | path->slots[0], struct btrfs_file_extent_item); | |
116 | btrfs_set_file_extent_generation(ei, trans->transid); | |
117 | btrfs_set_file_extent_type(ei, | |
118 | BTRFS_FILE_EXTENT_INLINE); | |
119 | ptr = btrfs_file_extent_inline_start(ei); | |
120 | btrfs_memcpy(root, path->nodes[0]->b_data, | |
121 | ptr, bh->b_data, offset + write_bytes); | |
122 | mark_buffer_dirty(path->nodes[0]); | |
123 | btrfs_free_path(path); | |
124 | } else if (buffer_mapped(bh)) { | |
125 | /* csum the file data */ | |
126 | btrfs_csum_file_block(trans, root, inode->i_ino, | |
127 | pages[i]->index << PAGE_CACHE_SHIFT, | |
128 | kmap(pages[i]), PAGE_CACHE_SIZE); | |
129 | kunmap(pages[i]); | |
130 | } | |
131 | SetPageChecked(pages[i]); | |
132 | ret = btrfs_end_transaction(trans, root); | |
133 | BUG_ON(ret); | |
134 | mutex_unlock(&root->fs_info->fs_mutex); | |
135 | ||
136 | ret = btrfs_commit_write(file, pages[i], offset, | |
137 | offset + this_write); | |
138 | pos += this_write; | |
139 | if (ret) { | |
140 | err = ret; | |
141 | goto failed; | |
142 | } | |
143 | WARN_ON(this_write > write_bytes); | |
144 | write_bytes -= this_write; | |
145 | } | |
146 | failed: | |
147 | return err; | |
148 | } | |
149 | ||
150 | /* | |
151 | * this is very complex, but the basic idea is to drop all extents | |
152 | * in the range start - end. hint_block is filled in with a block number | |
153 | * that would be a good hint to the block allocator for this file. | |
154 | * | |
155 | * If an extent intersects the range but is not entirely inside the range | |
156 | * it is either truncated or split. Anything entirely inside the range | |
157 | * is deleted from the tree. | |
158 | */ | |
159 | int btrfs_drop_extents(struct btrfs_trans_handle *trans, | |
160 | struct btrfs_root *root, struct inode *inode, | |
161 | u64 start, u64 end, u64 *hint_block) | |
162 | { | |
163 | int ret; | |
164 | struct btrfs_key key; | |
165 | struct btrfs_leaf *leaf; | |
166 | int slot; | |
167 | struct btrfs_file_extent_item *extent; | |
168 | u64 extent_end = 0; | |
169 | int keep; | |
170 | struct btrfs_file_extent_item old; | |
171 | struct btrfs_path *path; | |
172 | u64 search_start = start; | |
173 | int bookend; | |
174 | int found_type; | |
175 | int found_extent; | |
176 | int found_inline; | |
177 | ||
178 | path = btrfs_alloc_path(); | |
179 | if (!path) | |
180 | return -ENOMEM; | |
181 | while(1) { | |
182 | btrfs_release_path(root, path); | |
183 | ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino, | |
184 | search_start, -1); | |
185 | if (ret < 0) | |
186 | goto out; | |
187 | if (ret > 0) { | |
188 | if (path->slots[0] == 0) { | |
189 | ret = 0; | |
190 | goto out; | |
191 | } | |
192 | path->slots[0]--; | |
193 | } | |
194 | keep = 0; | |
195 | bookend = 0; | |
196 | found_extent = 0; | |
197 | found_inline = 0; | |
198 | extent = NULL; | |
199 | leaf = btrfs_buffer_leaf(path->nodes[0]); | |
200 | slot = path->slots[0]; | |
201 | btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key); | |
202 | if (key.offset >= end || key.objectid != inode->i_ino) { | |
203 | ret = 0; | |
204 | goto out; | |
205 | } | |
206 | if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY) { | |
207 | ret = 0; | |
208 | goto out; | |
209 | } | |
210 | extent = btrfs_item_ptr(leaf, slot, | |
211 | struct btrfs_file_extent_item); | |
212 | found_type = btrfs_file_extent_type(extent); | |
213 | if (found_type == BTRFS_FILE_EXTENT_REG) { | |
214 | extent_end = key.offset + | |
215 | (btrfs_file_extent_num_blocks(extent) << | |
216 | inode->i_blkbits); | |
217 | found_extent = 1; | |
218 | } else if (found_type == BTRFS_FILE_EXTENT_INLINE) { | |
219 | found_inline = 1; | |
220 | extent_end = key.offset + | |
221 | btrfs_file_extent_inline_len(leaf->items + slot); | |
222 | } | |
223 | ||
224 | /* we found nothing we can drop */ | |
225 | if (!found_extent && !found_inline) { | |
226 | ret = 0; | |
227 | goto out; | |
228 | } | |
229 | ||
230 | /* we found nothing inside the range */ | |
231 | if (search_start >= extent_end) { | |
232 | ret = 0; | |
233 | goto out; | |
234 | } | |
235 | ||
236 | /* FIXME, there's only one inline extent allowed right now */ | |
237 | if (found_inline) { | |
238 | u64 mask = root->blocksize - 1; | |
239 | search_start = (extent_end + mask) & ~mask; | |
240 | } else | |
241 | search_start = extent_end; | |
242 | ||
243 | if (end < extent_end && end >= key.offset) { | |
244 | if (found_extent) { | |
245 | u64 disk_blocknr = | |
246 | btrfs_file_extent_disk_blocknr(extent); | |
247 | u64 disk_num_blocks = | |
248 | btrfs_file_extent_disk_num_blocks(extent); | |
249 | memcpy(&old, extent, sizeof(old)); | |
250 | if (disk_blocknr != 0) { | |
251 | ret = btrfs_inc_extent_ref(trans, root, | |
252 | disk_blocknr, disk_num_blocks); | |
253 | BUG_ON(ret); | |
254 | } | |
255 | } | |
256 | WARN_ON(found_inline); | |
257 | bookend = 1; | |
258 | } | |
259 | ||
260 | /* truncate existing extent */ | |
261 | if (start > key.offset) { | |
262 | u64 new_num; | |
263 | u64 old_num; | |
264 | keep = 1; | |
265 | WARN_ON(start & (root->blocksize - 1)); | |
266 | if (found_extent) { | |
267 | new_num = (start - key.offset) >> | |
268 | inode->i_blkbits; | |
269 | old_num = btrfs_file_extent_num_blocks(extent); | |
270 | *hint_block = | |
271 | btrfs_file_extent_disk_blocknr(extent); | |
272 | if (btrfs_file_extent_disk_blocknr(extent)) { | |
273 | inode->i_blocks -= | |
274 | (old_num - new_num) << 3; | |
275 | } | |
276 | btrfs_set_file_extent_num_blocks(extent, | |
277 | new_num); | |
278 | mark_buffer_dirty(path->nodes[0]); | |
279 | } else { | |
280 | WARN_ON(1); | |
281 | } | |
282 | } | |
283 | /* delete the entire extent */ | |
284 | if (!keep) { | |
285 | u64 disk_blocknr = 0; | |
286 | u64 disk_num_blocks = 0; | |
287 | u64 extent_num_blocks = 0; | |
288 | if (found_extent) { | |
289 | disk_blocknr = | |
290 | btrfs_file_extent_disk_blocknr(extent); | |
291 | disk_num_blocks = | |
292 | btrfs_file_extent_disk_num_blocks(extent); | |
293 | extent_num_blocks = | |
294 | btrfs_file_extent_num_blocks(extent); | |
295 | *hint_block = | |
296 | btrfs_file_extent_disk_blocknr(extent); | |
297 | } | |
298 | ret = btrfs_del_item(trans, root, path); | |
299 | BUG_ON(ret); | |
300 | btrfs_release_path(root, path); | |
301 | extent = NULL; | |
302 | if (found_extent && disk_blocknr != 0) { | |
303 | inode->i_blocks -= extent_num_blocks << 3; | |
304 | ret = btrfs_free_extent(trans, root, | |
305 | disk_blocknr, | |
306 | disk_num_blocks, 0); | |
307 | } | |
308 | ||
309 | BUG_ON(ret); | |
310 | if (!bookend && search_start >= end) { | |
311 | ret = 0; | |
312 | goto out; | |
313 | } | |
314 | if (!bookend) | |
315 | continue; | |
316 | } | |
317 | /* create bookend, splitting the extent in two */ | |
318 | if (bookend && found_extent) { | |
319 | struct btrfs_key ins; | |
320 | ins.objectid = inode->i_ino; | |
321 | ins.offset = end; | |
322 | ins.flags = 0; | |
323 | btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY); | |
324 | ||
325 | btrfs_release_path(root, path); | |
326 | ret = btrfs_insert_empty_item(trans, root, path, &ins, | |
327 | sizeof(*extent)); | |
328 | BUG_ON(ret); | |
329 | extent = btrfs_item_ptr( | |
330 | btrfs_buffer_leaf(path->nodes[0]), | |
331 | path->slots[0], | |
332 | struct btrfs_file_extent_item); | |
333 | btrfs_set_file_extent_disk_blocknr(extent, | |
334 | btrfs_file_extent_disk_blocknr(&old)); | |
335 | btrfs_set_file_extent_disk_num_blocks(extent, | |
336 | btrfs_file_extent_disk_num_blocks(&old)); | |
337 | ||
338 | btrfs_set_file_extent_offset(extent, | |
339 | btrfs_file_extent_offset(&old) + | |
340 | ((end - key.offset) >> inode->i_blkbits)); | |
341 | WARN_ON(btrfs_file_extent_num_blocks(&old) < | |
342 | (extent_end - end) >> inode->i_blkbits); | |
343 | btrfs_set_file_extent_num_blocks(extent, | |
344 | (extent_end - end) >> inode->i_blkbits); | |
345 | ||
346 | btrfs_set_file_extent_type(extent, | |
347 | BTRFS_FILE_EXTENT_REG); | |
348 | btrfs_set_file_extent_generation(extent, | |
349 | btrfs_file_extent_generation(&old)); | |
350 | btrfs_mark_buffer_dirty(path->nodes[0]); | |
351 | if (btrfs_file_extent_disk_blocknr(&old) != 0) { | |
352 | inode->i_blocks += | |
353 | btrfs_file_extent_num_blocks(extent) << 3; | |
354 | } | |
355 | ret = 0; | |
356 | goto out; | |
357 | } | |
358 | } | |
359 | out: | |
360 | btrfs_free_path(path); | |
361 | return ret; | |
362 | } | |
363 | ||
364 | /* | |
365 | * this gets pages into the page cache and locks them down | |
366 | */ | |
367 | static int prepare_pages(struct btrfs_root *root, | |
368 | struct file *file, | |
369 | struct page **pages, | |
370 | size_t num_pages, | |
371 | loff_t pos, | |
372 | unsigned long first_index, | |
373 | unsigned long last_index, | |
374 | size_t write_bytes, | |
375 | u64 alloc_extent_start) | |
376 | { | |
377 | int i; | |
378 | unsigned long index = pos >> PAGE_CACHE_SHIFT; | |
379 | struct inode *inode = file->f_path.dentry->d_inode; | |
380 | int offset; | |
381 | int err = 0; | |
382 | int this_write; | |
383 | struct buffer_head *bh; | |
384 | struct buffer_head *head; | |
385 | loff_t isize = i_size_read(inode); | |
386 | ||
387 | memset(pages, 0, num_pages * sizeof(struct page *)); | |
388 | ||
389 | for (i = 0; i < num_pages; i++) { | |
390 | pages[i] = grab_cache_page(inode->i_mapping, index + i); | |
391 | if (!pages[i]) { | |
392 | err = -ENOMEM; | |
393 | goto failed_release; | |
394 | } | |
395 | cancel_dirty_page(pages[i], PAGE_CACHE_SIZE); | |
396 | wait_on_page_writeback(pages[i]); | |
397 | offset = pos & (PAGE_CACHE_SIZE -1); | |
84f54cfa | 398 | this_write = min((size_t)PAGE_CACHE_SIZE - offset, write_bytes); |
39279cc3 CM |
399 | if (!page_has_buffers(pages[i])) { |
400 | create_empty_buffers(pages[i], | |
401 | root->fs_info->sb->s_blocksize, | |
402 | (1 << BH_Uptodate)); | |
403 | } | |
404 | head = page_buffers(pages[i]); | |
405 | bh = head; | |
406 | do { | |
407 | err = btrfs_map_bh_to_logical(root, bh, | |
408 | alloc_extent_start); | |
409 | BUG_ON(err); | |
410 | if (err) | |
411 | goto failed_truncate; | |
412 | bh = bh->b_this_page; | |
413 | if (alloc_extent_start) | |
414 | alloc_extent_start++; | |
415 | } while (bh != head); | |
416 | pos += this_write; | |
417 | WARN_ON(this_write > write_bytes); | |
418 | write_bytes -= this_write; | |
419 | } | |
420 | return 0; | |
421 | ||
422 | failed_release: | |
423 | btrfs_drop_pages(pages, num_pages); | |
424 | return err; | |
425 | ||
426 | failed_truncate: | |
427 | btrfs_drop_pages(pages, num_pages); | |
428 | if (pos > isize) | |
429 | vmtruncate(inode, isize); | |
430 | return err; | |
431 | } | |
432 | ||
433 | static ssize_t btrfs_file_write(struct file *file, const char __user *buf, | |
434 | size_t count, loff_t *ppos) | |
435 | { | |
436 | loff_t pos; | |
437 | size_t num_written = 0; | |
438 | int err = 0; | |
439 | int ret = 0; | |
440 | struct inode *inode = file->f_path.dentry->d_inode; | |
441 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
442 | struct page *pages[8]; | |
443 | struct page *pinned[2]; | |
444 | unsigned long first_index; | |
445 | unsigned long last_index; | |
446 | u64 start_pos; | |
447 | u64 num_blocks; | |
448 | u64 alloc_extent_start; | |
449 | u64 hint_block; | |
450 | struct btrfs_trans_handle *trans; | |
451 | struct btrfs_key ins; | |
452 | pinned[0] = NULL; | |
453 | pinned[1] = NULL; | |
454 | if (file->f_flags & O_DIRECT) | |
455 | return -EINVAL; | |
456 | pos = *ppos; | |
457 | vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE); | |
458 | current->backing_dev_info = inode->i_mapping->backing_dev_info; | |
459 | err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode)); | |
460 | if (err) | |
461 | goto out; | |
462 | if (count == 0) | |
463 | goto out; | |
464 | err = remove_suid(file->f_path.dentry); | |
465 | if (err) | |
466 | goto out; | |
467 | file_update_time(file); | |
468 | ||
469 | start_pos = pos & ~((u64)PAGE_CACHE_SIZE - 1); | |
470 | num_blocks = (count + pos - start_pos + root->blocksize - 1) >> | |
471 | inode->i_blkbits; | |
472 | ||
473 | mutex_lock(&inode->i_mutex); | |
474 | first_index = pos >> PAGE_CACHE_SHIFT; | |
475 | last_index = (pos + count) >> PAGE_CACHE_SHIFT; | |
476 | ||
477 | /* | |
478 | * there are lots of better ways to do this, but this code | |
479 | * makes sure the first and last page in the file range are | |
480 | * up to date and ready for cow | |
481 | */ | |
482 | if ((pos & (PAGE_CACHE_SIZE - 1))) { | |
483 | pinned[0] = grab_cache_page(inode->i_mapping, first_index); | |
484 | if (!PageUptodate(pinned[0])) { | |
485 | ret = mpage_readpage(pinned[0], btrfs_get_block); | |
486 | BUG_ON(ret); | |
487 | wait_on_page_locked(pinned[0]); | |
488 | } else { | |
489 | unlock_page(pinned[0]); | |
490 | } | |
491 | } | |
492 | if ((pos + count) & (PAGE_CACHE_SIZE - 1)) { | |
493 | pinned[1] = grab_cache_page(inode->i_mapping, last_index); | |
494 | if (!PageUptodate(pinned[1])) { | |
495 | ret = mpage_readpage(pinned[1], btrfs_get_block); | |
496 | BUG_ON(ret); | |
497 | wait_on_page_locked(pinned[1]); | |
498 | } else { | |
499 | unlock_page(pinned[1]); | |
500 | } | |
501 | } | |
502 | ||
503 | mutex_lock(&root->fs_info->fs_mutex); | |
504 | trans = btrfs_start_transaction(root, 1); | |
505 | if (!trans) { | |
506 | err = -ENOMEM; | |
507 | mutex_unlock(&root->fs_info->fs_mutex); | |
508 | goto out_unlock; | |
509 | } | |
510 | btrfs_set_trans_block_group(trans, inode); | |
511 | /* FIXME blocksize != 4096 */ | |
512 | inode->i_blocks += num_blocks << 3; | |
513 | hint_block = 0; | |
514 | ||
515 | /* FIXME...EIEIO, ENOSPC and more */ | |
516 | ||
517 | /* step one, delete the existing extents in this range */ | |
518 | if (start_pos < inode->i_size) { | |
519 | /* FIXME blocksize != pagesize */ | |
520 | ret = btrfs_drop_extents(trans, root, inode, | |
521 | start_pos, | |
522 | (pos + count + root->blocksize -1) & | |
523 | ~((u64)root->blocksize - 1), | |
524 | &hint_block); | |
525 | BUG_ON(ret); | |
526 | } | |
527 | ||
528 | /* insert any holes we need to create */ | |
529 | if (inode->i_size < start_pos) { | |
530 | u64 last_pos_in_file; | |
531 | u64 hole_size; | |
532 | u64 mask = root->blocksize - 1; | |
533 | last_pos_in_file = (inode->i_size + mask) & ~mask; | |
534 | hole_size = (start_pos - last_pos_in_file + mask) & ~mask; | |
535 | hole_size >>= inode->i_blkbits; | |
536 | if (last_pos_in_file < start_pos) { | |
537 | ret = btrfs_insert_file_extent(trans, root, | |
538 | inode->i_ino, | |
539 | last_pos_in_file, | |
540 | 0, 0, hole_size); | |
541 | } | |
542 | BUG_ON(ret); | |
543 | } | |
544 | ||
545 | /* | |
546 | * either allocate an extent for the new bytes or setup the key | |
547 | * to show we are doing inline data in the extent | |
548 | */ | |
549 | if (inode->i_size >= PAGE_CACHE_SIZE || pos + count < inode->i_size || | |
550 | pos + count - start_pos > BTRFS_MAX_INLINE_DATA_SIZE(root)) { | |
551 | ret = btrfs_alloc_extent(trans, root, inode->i_ino, | |
552 | num_blocks, hint_block, (u64)-1, | |
553 | &ins, 1); | |
554 | BUG_ON(ret); | |
555 | ret = btrfs_insert_file_extent(trans, root, inode->i_ino, | |
556 | start_pos, ins.objectid, ins.offset, | |
557 | ins.offset); | |
558 | BUG_ON(ret); | |
559 | } else { | |
560 | ins.offset = 0; | |
561 | ins.objectid = 0; | |
562 | } | |
563 | BUG_ON(ret); | |
564 | alloc_extent_start = ins.objectid; | |
565 | ret = btrfs_end_transaction(trans, root); | |
566 | mutex_unlock(&root->fs_info->fs_mutex); | |
567 | ||
568 | while(count > 0) { | |
569 | size_t offset = pos & (PAGE_CACHE_SIZE - 1); | |
84f54cfa CM |
570 | size_t write_bytes = min(count, |
571 | (size_t)PAGE_CACHE_SIZE - offset); | |
39279cc3 CM |
572 | size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >> |
573 | PAGE_CACHE_SHIFT; | |
574 | ||
575 | memset(pages, 0, sizeof(pages)); | |
576 | ret = prepare_pages(root, file, pages, num_pages, | |
577 | pos, first_index, last_index, | |
578 | write_bytes, alloc_extent_start); | |
579 | BUG_ON(ret); | |
580 | ||
581 | /* FIXME blocks != pagesize */ | |
582 | if (alloc_extent_start) | |
583 | alloc_extent_start += num_pages; | |
584 | ret = btrfs_copy_from_user(pos, num_pages, | |
585 | write_bytes, pages, buf); | |
586 | BUG_ON(ret); | |
587 | ||
588 | ret = dirty_and_release_pages(NULL, root, file, pages, | |
589 | num_pages, pos, write_bytes); | |
590 | BUG_ON(ret); | |
591 | btrfs_drop_pages(pages, num_pages); | |
592 | ||
593 | buf += write_bytes; | |
594 | count -= write_bytes; | |
595 | pos += write_bytes; | |
596 | num_written += write_bytes; | |
597 | ||
598 | balance_dirty_pages_ratelimited(inode->i_mapping); | |
599 | btrfs_btree_balance_dirty(root); | |
600 | cond_resched(); | |
601 | } | |
602 | out_unlock: | |
603 | mutex_unlock(&inode->i_mutex); | |
604 | out: | |
605 | if (pinned[0]) | |
606 | page_cache_release(pinned[0]); | |
607 | if (pinned[1]) | |
608 | page_cache_release(pinned[1]); | |
609 | *ppos = pos; | |
610 | current->backing_dev_info = NULL; | |
611 | mark_inode_dirty(inode); | |
612 | return num_written ? num_written : err; | |
613 | } | |
614 | ||
615 | /* | |
616 | * FIXME, do this by stuffing the csum we want in the info hanging off | |
617 | * page->private. For now, verify file csums on read | |
618 | */ | |
619 | static int btrfs_read_actor(read_descriptor_t *desc, struct page *page, | |
620 | unsigned long offset, unsigned long size) | |
621 | { | |
622 | char *kaddr; | |
623 | unsigned long left, count = desc->count; | |
624 | struct inode *inode = page->mapping->host; | |
625 | ||
626 | if (size > count) | |
627 | size = count; | |
628 | ||
629 | if (!PageChecked(page)) { | |
630 | /* FIXME, do it per block */ | |
631 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
632 | int ret; | |
633 | struct buffer_head *bh; | |
634 | ||
635 | if (page_has_buffers(page)) { | |
636 | bh = page_buffers(page); | |
637 | if (!buffer_mapped(bh)) { | |
638 | SetPageChecked(page); | |
639 | goto checked; | |
640 | } | |
641 | } | |
642 | ||
643 | ret = btrfs_csum_verify_file_block(root, | |
644 | page->mapping->host->i_ino, | |
645 | page->index << PAGE_CACHE_SHIFT, | |
646 | kmap(page), PAGE_CACHE_SIZE); | |
647 | if (ret) { | |
648 | if (ret != -ENOENT) { | |
649 | printk("failed to verify ino %lu page %lu ret %d\n", | |
650 | page->mapping->host->i_ino, | |
651 | page->index, ret); | |
652 | memset(page_address(page), 1, PAGE_CACHE_SIZE); | |
653 | flush_dcache_page(page); | |
654 | } | |
655 | } | |
656 | SetPageChecked(page); | |
657 | kunmap(page); | |
658 | } | |
659 | checked: | |
660 | /* | |
661 | * Faults on the destination of a read are common, so do it before | |
662 | * taking the kmap. | |
663 | */ | |
664 | if (!fault_in_pages_writeable(desc->arg.buf, size)) { | |
665 | kaddr = kmap_atomic(page, KM_USER0); | |
666 | left = __copy_to_user_inatomic(desc->arg.buf, | |
667 | kaddr + offset, size); | |
668 | kunmap_atomic(kaddr, KM_USER0); | |
669 | if (left == 0) | |
670 | goto success; | |
671 | } | |
672 | ||
673 | /* Do it the slow way */ | |
674 | kaddr = kmap(page); | |
675 | left = __copy_to_user(desc->arg.buf, kaddr + offset, size); | |
676 | kunmap(page); | |
677 | ||
678 | if (left) { | |
679 | size -= left; | |
680 | desc->error = -EFAULT; | |
681 | } | |
682 | success: | |
683 | desc->count = count - size; | |
684 | desc->written += size; | |
685 | desc->arg.buf += size; | |
686 | return size; | |
687 | } | |
688 | ||
689 | /** | |
690 | * btrfs_file_aio_read - filesystem read routine, with a mod to csum verify | |
691 | * @iocb: kernel I/O control block | |
692 | * @iov: io vector request | |
693 | * @nr_segs: number of segments in the iovec | |
694 | * @pos: current file position | |
695 | */ | |
696 | static ssize_t btrfs_file_aio_read(struct kiocb *iocb, const struct iovec *iov, | |
697 | unsigned long nr_segs, loff_t pos) | |
698 | { | |
699 | struct file *filp = iocb->ki_filp; | |
700 | ssize_t retval; | |
701 | unsigned long seg; | |
702 | size_t count; | |
703 | loff_t *ppos = &iocb->ki_pos; | |
704 | ||
705 | count = 0; | |
706 | for (seg = 0; seg < nr_segs; seg++) { | |
707 | const struct iovec *iv = &iov[seg]; | |
708 | ||
709 | /* | |
710 | * If any segment has a negative length, or the cumulative | |
711 | * length ever wraps negative then return -EINVAL. | |
712 | */ | |
713 | count += iv->iov_len; | |
714 | if (unlikely((ssize_t)(count|iv->iov_len) < 0)) | |
715 | return -EINVAL; | |
716 | if (access_ok(VERIFY_WRITE, iv->iov_base, iv->iov_len)) | |
717 | continue; | |
718 | if (seg == 0) | |
719 | return -EFAULT; | |
720 | nr_segs = seg; | |
721 | count -= iv->iov_len; /* This segment is no good */ | |
722 | break; | |
723 | } | |
724 | retval = 0; | |
725 | if (count) { | |
726 | for (seg = 0; seg < nr_segs; seg++) { | |
727 | read_descriptor_t desc; | |
728 | ||
729 | desc.written = 0; | |
730 | desc.arg.buf = iov[seg].iov_base; | |
731 | desc.count = iov[seg].iov_len; | |
732 | if (desc.count == 0) | |
733 | continue; | |
734 | desc.error = 0; | |
735 | do_generic_file_read(filp, ppos, &desc, | |
736 | btrfs_read_actor); | |
737 | retval += desc.written; | |
738 | if (desc.error) { | |
739 | retval = retval ?: desc.error; | |
740 | break; | |
741 | } | |
742 | } | |
743 | } | |
744 | return retval; | |
745 | } | |
746 | ||
747 | static int btrfs_sync_file(struct file *file, | |
748 | struct dentry *dentry, int datasync) | |
749 | { | |
750 | struct inode *inode = dentry->d_inode; | |
751 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
752 | int ret; | |
753 | struct btrfs_trans_handle *trans; | |
754 | ||
755 | /* | |
756 | * FIXME, use inode generation number to check if we can skip the | |
757 | * commit | |
758 | */ | |
759 | mutex_lock(&root->fs_info->fs_mutex); | |
760 | trans = btrfs_start_transaction(root, 1); | |
761 | if (!trans) { | |
762 | ret = -ENOMEM; | |
763 | goto out; | |
764 | } | |
765 | ret = btrfs_commit_transaction(trans, root); | |
766 | mutex_unlock(&root->fs_info->fs_mutex); | |
767 | out: | |
768 | return ret > 0 ? EIO : ret; | |
769 | } | |
770 | ||
771 | struct file_operations btrfs_file_operations = { | |
772 | .llseek = generic_file_llseek, | |
773 | .read = do_sync_read, | |
774 | .aio_read = btrfs_file_aio_read, | |
775 | .write = btrfs_file_write, | |
776 | .mmap = generic_file_mmap, | |
777 | .open = generic_file_open, | |
778 | .ioctl = btrfs_ioctl, | |
779 | .fsync = btrfs_sync_file, | |
780 | #ifdef CONFIG_COMPAT | |
781 | .compat_ioctl = btrfs_compat_ioctl, | |
782 | #endif | |
783 | }; | |
784 |