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1 | /* | |
2 | * linux/fs/ext4/file.c | |
3 | * | |
4 | * Copyright (C) 1992, 1993, 1994, 1995 | |
5 | * Remy Card (card@masi.ibp.fr) | |
6 | * Laboratoire MASI - Institut Blaise Pascal | |
7 | * Universite Pierre et Marie Curie (Paris VI) | |
8 | * | |
9 | * from | |
10 | * | |
11 | * linux/fs/minix/file.c | |
12 | * | |
13 | * Copyright (C) 1991, 1992 Linus Torvalds | |
14 | * | |
15 | * ext4 fs regular file handling primitives | |
16 | * | |
17 | * 64-bit file support on 64-bit platforms by Jakub Jelinek | |
18 | * (jj@sunsite.ms.mff.cuni.cz) | |
19 | */ | |
20 | ||
21 | #include <linux/time.h> | |
22 | #include <linux/fs.h> | |
23 | #include <linux/mount.h> | |
24 | #include <linux/path.h> | |
25 | #include <linux/dax.h> | |
26 | #include <linux/quotaops.h> | |
27 | #include <linux/pagevec.h> | |
28 | #include <linux/uio.h> | |
29 | #include "ext4.h" | |
30 | #include "ext4_jbd2.h" | |
31 | #include "xattr.h" | |
32 | #include "acl.h" | |
33 | ||
34 | /* | |
35 | * Called when an inode is released. Note that this is different | |
36 | * from ext4_file_open: open gets called at every open, but release | |
37 | * gets called only when /all/ the files are closed. | |
38 | */ | |
39 | static int ext4_release_file(struct inode *inode, struct file *filp) | |
40 | { | |
41 | if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) { | |
42 | ext4_alloc_da_blocks(inode); | |
43 | ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE); | |
44 | } | |
45 | /* if we are the last writer on the inode, drop the block reservation */ | |
46 | if ((filp->f_mode & FMODE_WRITE) && | |
47 | (atomic_read(&inode->i_writecount) == 1) && | |
48 | !EXT4_I(inode)->i_reserved_data_blocks) | |
49 | { | |
50 | down_write(&EXT4_I(inode)->i_data_sem); | |
51 | ext4_discard_preallocations(inode); | |
52 | up_write(&EXT4_I(inode)->i_data_sem); | |
53 | } | |
54 | if (is_dx(inode) && filp->private_data) | |
55 | ext4_htree_free_dir_info(filp->private_data); | |
56 | ||
57 | return 0; | |
58 | } | |
59 | ||
60 | static void ext4_unwritten_wait(struct inode *inode) | |
61 | { | |
62 | wait_queue_head_t *wq = ext4_ioend_wq(inode); | |
63 | ||
64 | wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_unwritten) == 0)); | |
65 | } | |
66 | ||
67 | /* | |
68 | * This tests whether the IO in question is block-aligned or not. | |
69 | * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they | |
70 | * are converted to written only after the IO is complete. Until they are | |
71 | * mapped, these blocks appear as holes, so dio_zero_block() will assume that | |
72 | * it needs to zero out portions of the start and/or end block. If 2 AIO | |
73 | * threads are at work on the same unwritten block, they must be synchronized | |
74 | * or one thread will zero the other's data, causing corruption. | |
75 | */ | |
76 | static int | |
77 | ext4_unaligned_aio(struct inode *inode, struct iov_iter *from, loff_t pos) | |
78 | { | |
79 | struct super_block *sb = inode->i_sb; | |
80 | int blockmask = sb->s_blocksize - 1; | |
81 | ||
82 | if (pos >= i_size_read(inode)) | |
83 | return 0; | |
84 | ||
85 | if ((pos | iov_iter_alignment(from)) & blockmask) | |
86 | return 1; | |
87 | ||
88 | return 0; | |
89 | } | |
90 | ||
91 | static ssize_t | |
92 | ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from) | |
93 | { | |
94 | struct file *file = iocb->ki_filp; | |
95 | struct inode *inode = file_inode(iocb->ki_filp); | |
96 | struct blk_plug plug; | |
97 | int o_direct = iocb->ki_flags & IOCB_DIRECT; | |
98 | int unaligned_aio = 0; | |
99 | int overwrite = 0; | |
100 | ssize_t ret; | |
101 | ||
102 | inode_lock(inode); | |
103 | ret = generic_write_checks(iocb, from); | |
104 | if (ret <= 0) | |
105 | goto out; | |
106 | ||
107 | /* | |
108 | * Unaligned direct AIO must be serialized among each other as zeroing | |
109 | * of partial blocks of two competing unaligned AIOs can result in data | |
110 | * corruption. | |
111 | */ | |
112 | if (o_direct && ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) && | |
113 | !is_sync_kiocb(iocb) && | |
114 | ext4_unaligned_aio(inode, from, iocb->ki_pos)) { | |
115 | unaligned_aio = 1; | |
116 | ext4_unwritten_wait(inode); | |
117 | } | |
118 | ||
119 | /* | |
120 | * If we have encountered a bitmap-format file, the size limit | |
121 | * is smaller than s_maxbytes, which is for extent-mapped files. | |
122 | */ | |
123 | if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) { | |
124 | struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); | |
125 | ||
126 | if (iocb->ki_pos >= sbi->s_bitmap_maxbytes) { | |
127 | ret = -EFBIG; | |
128 | goto out; | |
129 | } | |
130 | iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos); | |
131 | } | |
132 | ||
133 | iocb->private = &overwrite; | |
134 | if (o_direct) { | |
135 | size_t length = iov_iter_count(from); | |
136 | loff_t pos = iocb->ki_pos; | |
137 | blk_start_plug(&plug); | |
138 | ||
139 | /* check whether we do a DIO overwrite or not */ | |
140 | if (ext4_should_dioread_nolock(inode) && !unaligned_aio && | |
141 | !file->f_mapping->nrpages && pos + length <= i_size_read(inode)) { | |
142 | struct ext4_map_blocks map; | |
143 | unsigned int blkbits = inode->i_blkbits; | |
144 | int err, len; | |
145 | ||
146 | map.m_lblk = pos >> blkbits; | |
147 | map.m_len = (EXT4_BLOCK_ALIGN(pos + length, blkbits) >> blkbits) | |
148 | - map.m_lblk; | |
149 | len = map.m_len; | |
150 | ||
151 | err = ext4_map_blocks(NULL, inode, &map, 0); | |
152 | /* | |
153 | * 'err==len' means that all of blocks has | |
154 | * been preallocated no matter they are | |
155 | * initialized or not. For excluding | |
156 | * unwritten extents, we need to check | |
157 | * m_flags. There are two conditions that | |
158 | * indicate for initialized extents. 1) If we | |
159 | * hit extent cache, EXT4_MAP_MAPPED flag is | |
160 | * returned; 2) If we do a real lookup, | |
161 | * non-flags are returned. So we should check | |
162 | * these two conditions. | |
163 | */ | |
164 | if (err == len && (map.m_flags & EXT4_MAP_MAPPED)) | |
165 | overwrite = 1; | |
166 | } | |
167 | } | |
168 | ||
169 | ret = __generic_file_write_iter(iocb, from); | |
170 | inode_unlock(inode); | |
171 | ||
172 | if (ret > 0) { | |
173 | ssize_t err; | |
174 | ||
175 | err = generic_write_sync(file, iocb->ki_pos - ret, ret); | |
176 | if (err < 0) | |
177 | ret = err; | |
178 | } | |
179 | if (o_direct) | |
180 | blk_finish_plug(&plug); | |
181 | ||
182 | return ret; | |
183 | ||
184 | out: | |
185 | inode_unlock(inode); | |
186 | return ret; | |
187 | } | |
188 | ||
189 | #ifdef CONFIG_FS_DAX | |
190 | static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf) | |
191 | { | |
192 | int result; | |
193 | handle_t *handle = NULL; | |
194 | struct inode *inode = file_inode(vma->vm_file); | |
195 | struct super_block *sb = inode->i_sb; | |
196 | bool write = vmf->flags & FAULT_FLAG_WRITE; | |
197 | ||
198 | if (write) { | |
199 | sb_start_pagefault(sb); | |
200 | file_update_time(vma->vm_file); | |
201 | down_read(&EXT4_I(inode)->i_mmap_sem); | |
202 | handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE, | |
203 | EXT4_DATA_TRANS_BLOCKS(sb)); | |
204 | } else | |
205 | down_read(&EXT4_I(inode)->i_mmap_sem); | |
206 | ||
207 | if (IS_ERR(handle)) | |
208 | result = VM_FAULT_SIGBUS; | |
209 | else | |
210 | result = __dax_fault(vma, vmf, ext4_dax_mmap_get_block, NULL); | |
211 | ||
212 | if (write) { | |
213 | if (!IS_ERR(handle)) | |
214 | ext4_journal_stop(handle); | |
215 | up_read(&EXT4_I(inode)->i_mmap_sem); | |
216 | sb_end_pagefault(sb); | |
217 | } else | |
218 | up_read(&EXT4_I(inode)->i_mmap_sem); | |
219 | ||
220 | return result; | |
221 | } | |
222 | ||
223 | static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr, | |
224 | pmd_t *pmd, unsigned int flags) | |
225 | { | |
226 | int result; | |
227 | handle_t *handle = NULL; | |
228 | struct inode *inode = file_inode(vma->vm_file); | |
229 | struct super_block *sb = inode->i_sb; | |
230 | bool write = flags & FAULT_FLAG_WRITE; | |
231 | ||
232 | if (write) { | |
233 | sb_start_pagefault(sb); | |
234 | file_update_time(vma->vm_file); | |
235 | down_read(&EXT4_I(inode)->i_mmap_sem); | |
236 | handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE, | |
237 | ext4_chunk_trans_blocks(inode, | |
238 | PMD_SIZE / PAGE_SIZE)); | |
239 | } else | |
240 | down_read(&EXT4_I(inode)->i_mmap_sem); | |
241 | ||
242 | if (IS_ERR(handle)) | |
243 | result = VM_FAULT_SIGBUS; | |
244 | else | |
245 | result = __dax_pmd_fault(vma, addr, pmd, flags, | |
246 | ext4_dax_mmap_get_block, NULL); | |
247 | ||
248 | if (write) { | |
249 | if (!IS_ERR(handle)) | |
250 | ext4_journal_stop(handle); | |
251 | up_read(&EXT4_I(inode)->i_mmap_sem); | |
252 | sb_end_pagefault(sb); | |
253 | } else | |
254 | up_read(&EXT4_I(inode)->i_mmap_sem); | |
255 | ||
256 | return result; | |
257 | } | |
258 | ||
259 | /* | |
260 | * Handle write fault for VM_MIXEDMAP mappings. Similarly to ext4_dax_fault() | |
261 | * handler we check for races agaist truncate. Note that since we cycle through | |
262 | * i_mmap_sem, we are sure that also any hole punching that began before we | |
263 | * were called is finished by now and so if it included part of the file we | |
264 | * are working on, our pte will get unmapped and the check for pte_same() in | |
265 | * wp_pfn_shared() fails. Thus fault gets retried and things work out as | |
266 | * desired. | |
267 | */ | |
268 | static int ext4_dax_pfn_mkwrite(struct vm_area_struct *vma, | |
269 | struct vm_fault *vmf) | |
270 | { | |
271 | struct inode *inode = file_inode(vma->vm_file); | |
272 | struct super_block *sb = inode->i_sb; | |
273 | loff_t size; | |
274 | int ret; | |
275 | ||
276 | sb_start_pagefault(sb); | |
277 | file_update_time(vma->vm_file); | |
278 | down_read(&EXT4_I(inode)->i_mmap_sem); | |
279 | size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
280 | if (vmf->pgoff >= size) | |
281 | ret = VM_FAULT_SIGBUS; | |
282 | else | |
283 | ret = dax_pfn_mkwrite(vma, vmf); | |
284 | up_read(&EXT4_I(inode)->i_mmap_sem); | |
285 | sb_end_pagefault(sb); | |
286 | ||
287 | return ret; | |
288 | } | |
289 | ||
290 | static const struct vm_operations_struct ext4_dax_vm_ops = { | |
291 | .fault = ext4_dax_fault, | |
292 | .pmd_fault = ext4_dax_pmd_fault, | |
293 | .page_mkwrite = ext4_dax_fault, | |
294 | .pfn_mkwrite = ext4_dax_pfn_mkwrite, | |
295 | }; | |
296 | #else | |
297 | #define ext4_dax_vm_ops ext4_file_vm_ops | |
298 | #endif | |
299 | ||
300 | static const struct vm_operations_struct ext4_file_vm_ops = { | |
301 | .fault = ext4_filemap_fault, | |
302 | .map_pages = filemap_map_pages, | |
303 | .page_mkwrite = ext4_page_mkwrite, | |
304 | }; | |
305 | ||
306 | static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma) | |
307 | { | |
308 | struct inode *inode = file->f_mapping->host; | |
309 | ||
310 | if (ext4_encrypted_inode(inode)) { | |
311 | int err = ext4_get_encryption_info(inode); | |
312 | if (err) | |
313 | return 0; | |
314 | if (ext4_encryption_info(inode) == NULL) | |
315 | return -ENOKEY; | |
316 | } | |
317 | file_accessed(file); | |
318 | if (IS_DAX(file_inode(file))) { | |
319 | vma->vm_ops = &ext4_dax_vm_ops; | |
320 | vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE; | |
321 | } else { | |
322 | vma->vm_ops = &ext4_file_vm_ops; | |
323 | } | |
324 | return 0; | |
325 | } | |
326 | ||
327 | static int ext4_file_open(struct inode * inode, struct file * filp) | |
328 | { | |
329 | struct super_block *sb = inode->i_sb; | |
330 | struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); | |
331 | struct vfsmount *mnt = filp->f_path.mnt; | |
332 | struct dentry *dir; | |
333 | struct path path; | |
334 | char buf[64], *cp; | |
335 | int ret; | |
336 | ||
337 | if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) && | |
338 | !(sb->s_flags & MS_RDONLY))) { | |
339 | sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED; | |
340 | /* | |
341 | * Sample where the filesystem has been mounted and | |
342 | * store it in the superblock for sysadmin convenience | |
343 | * when trying to sort through large numbers of block | |
344 | * devices or filesystem images. | |
345 | */ | |
346 | memset(buf, 0, sizeof(buf)); | |
347 | path.mnt = mnt; | |
348 | path.dentry = mnt->mnt_root; | |
349 | cp = d_path(&path, buf, sizeof(buf)); | |
350 | if (!IS_ERR(cp)) { | |
351 | handle_t *handle; | |
352 | int err; | |
353 | ||
354 | handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1); | |
355 | if (IS_ERR(handle)) | |
356 | return PTR_ERR(handle); | |
357 | BUFFER_TRACE(sbi->s_sbh, "get_write_access"); | |
358 | err = ext4_journal_get_write_access(handle, sbi->s_sbh); | |
359 | if (err) { | |
360 | ext4_journal_stop(handle); | |
361 | return err; | |
362 | } | |
363 | strlcpy(sbi->s_es->s_last_mounted, cp, | |
364 | sizeof(sbi->s_es->s_last_mounted)); | |
365 | ext4_handle_dirty_super(handle, sb); | |
366 | ext4_journal_stop(handle); | |
367 | } | |
368 | } | |
369 | if (ext4_encrypted_inode(inode)) { | |
370 | ret = ext4_get_encryption_info(inode); | |
371 | if (ret) | |
372 | return -EACCES; | |
373 | if (ext4_encryption_info(inode) == NULL) | |
374 | return -ENOKEY; | |
375 | } | |
376 | ||
377 | dir = dget_parent(file_dentry(filp)); | |
378 | if (ext4_encrypted_inode(d_inode(dir)) && | |
379 | !ext4_is_child_context_consistent_with_parent(d_inode(dir), inode)) { | |
380 | ext4_warning(inode->i_sb, | |
381 | "Inconsistent encryption contexts: %lu/%lu\n", | |
382 | (unsigned long) d_inode(dir)->i_ino, | |
383 | (unsigned long) inode->i_ino); | |
384 | dput(dir); | |
385 | return -EPERM; | |
386 | } | |
387 | dput(dir); | |
388 | /* | |
389 | * Set up the jbd2_inode if we are opening the inode for | |
390 | * writing and the journal is present | |
391 | */ | |
392 | if (filp->f_mode & FMODE_WRITE) { | |
393 | ret = ext4_inode_attach_jinode(inode); | |
394 | if (ret < 0) | |
395 | return ret; | |
396 | } | |
397 | return dquot_file_open(inode, filp); | |
398 | } | |
399 | ||
400 | /* | |
401 | * Here we use ext4_map_blocks() to get a block mapping for a extent-based | |
402 | * file rather than ext4_ext_walk_space() because we can introduce | |
403 | * SEEK_DATA/SEEK_HOLE for block-mapped and extent-mapped file at the same | |
404 | * function. When extent status tree has been fully implemented, it will | |
405 | * track all extent status for a file and we can directly use it to | |
406 | * retrieve the offset for SEEK_DATA/SEEK_HOLE. | |
407 | */ | |
408 | ||
409 | /* | |
410 | * When we retrieve the offset for SEEK_DATA/SEEK_HOLE, we would need to | |
411 | * lookup page cache to check whether or not there has some data between | |
412 | * [startoff, endoff] because, if this range contains an unwritten extent, | |
413 | * we determine this extent as a data or a hole according to whether the | |
414 | * page cache has data or not. | |
415 | */ | |
416 | static int ext4_find_unwritten_pgoff(struct inode *inode, | |
417 | int whence, | |
418 | ext4_lblk_t end_blk, | |
419 | loff_t *offset) | |
420 | { | |
421 | struct pagevec pvec; | |
422 | unsigned int blkbits; | |
423 | pgoff_t index; | |
424 | pgoff_t end; | |
425 | loff_t endoff; | |
426 | loff_t startoff; | |
427 | loff_t lastoff; | |
428 | int found = 0; | |
429 | ||
430 | blkbits = inode->i_sb->s_blocksize_bits; | |
431 | startoff = *offset; | |
432 | lastoff = startoff; | |
433 | endoff = (loff_t)end_blk << blkbits; | |
434 | ||
435 | index = startoff >> PAGE_SHIFT; | |
436 | end = endoff >> PAGE_SHIFT; | |
437 | ||
438 | pagevec_init(&pvec, 0); | |
439 | do { | |
440 | int i, num; | |
441 | unsigned long nr_pages; | |
442 | ||
443 | num = min_t(pgoff_t, end - index, PAGEVEC_SIZE); | |
444 | nr_pages = pagevec_lookup(&pvec, inode->i_mapping, index, | |
445 | (pgoff_t)num); | |
446 | if (nr_pages == 0) { | |
447 | if (whence == SEEK_DATA) | |
448 | break; | |
449 | ||
450 | BUG_ON(whence != SEEK_HOLE); | |
451 | /* | |
452 | * If this is the first time to go into the loop and | |
453 | * offset is not beyond the end offset, it will be a | |
454 | * hole at this offset | |
455 | */ | |
456 | if (lastoff == startoff || lastoff < endoff) | |
457 | found = 1; | |
458 | break; | |
459 | } | |
460 | ||
461 | /* | |
462 | * If this is the first time to go into the loop and | |
463 | * offset is smaller than the first page offset, it will be a | |
464 | * hole at this offset. | |
465 | */ | |
466 | if (lastoff == startoff && whence == SEEK_HOLE && | |
467 | lastoff < page_offset(pvec.pages[0])) { | |
468 | found = 1; | |
469 | break; | |
470 | } | |
471 | ||
472 | for (i = 0; i < nr_pages; i++) { | |
473 | struct page *page = pvec.pages[i]; | |
474 | struct buffer_head *bh, *head; | |
475 | ||
476 | /* | |
477 | * If the current offset is not beyond the end of given | |
478 | * range, it will be a hole. | |
479 | */ | |
480 | if (lastoff < endoff && whence == SEEK_HOLE && | |
481 | page->index > end) { | |
482 | found = 1; | |
483 | *offset = lastoff; | |
484 | goto out; | |
485 | } | |
486 | ||
487 | lock_page(page); | |
488 | ||
489 | if (unlikely(page->mapping != inode->i_mapping)) { | |
490 | unlock_page(page); | |
491 | continue; | |
492 | } | |
493 | ||
494 | if (!page_has_buffers(page)) { | |
495 | unlock_page(page); | |
496 | continue; | |
497 | } | |
498 | ||
499 | if (page_has_buffers(page)) { | |
500 | lastoff = page_offset(page); | |
501 | bh = head = page_buffers(page); | |
502 | do { | |
503 | if (buffer_uptodate(bh) || | |
504 | buffer_unwritten(bh)) { | |
505 | if (whence == SEEK_DATA) | |
506 | found = 1; | |
507 | } else { | |
508 | if (whence == SEEK_HOLE) | |
509 | found = 1; | |
510 | } | |
511 | if (found) { | |
512 | *offset = max_t(loff_t, | |
513 | startoff, lastoff); | |
514 | unlock_page(page); | |
515 | goto out; | |
516 | } | |
517 | lastoff += bh->b_size; | |
518 | bh = bh->b_this_page; | |
519 | } while (bh != head); | |
520 | } | |
521 | ||
522 | lastoff = page_offset(page) + PAGE_SIZE; | |
523 | unlock_page(page); | |
524 | } | |
525 | ||
526 | /* | |
527 | * The no. of pages is less than our desired, that would be a | |
528 | * hole in there. | |
529 | */ | |
530 | if (nr_pages < num && whence == SEEK_HOLE) { | |
531 | found = 1; | |
532 | *offset = lastoff; | |
533 | break; | |
534 | } | |
535 | ||
536 | index = pvec.pages[i - 1]->index + 1; | |
537 | pagevec_release(&pvec); | |
538 | } while (index <= end); | |
539 | ||
540 | out: | |
541 | pagevec_release(&pvec); | |
542 | return found; | |
543 | } | |
544 | ||
545 | /* | |
546 | * ext4_seek_data() retrieves the offset for SEEK_DATA. | |
547 | */ | |
548 | static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize) | |
549 | { | |
550 | struct inode *inode = file->f_mapping->host; | |
551 | struct extent_status es; | |
552 | ext4_lblk_t start, last, end; | |
553 | loff_t dataoff, isize; | |
554 | int blkbits; | |
555 | int ret; | |
556 | ||
557 | inode_lock(inode); | |
558 | ||
559 | isize = i_size_read(inode); | |
560 | if (offset >= isize) { | |
561 | inode_unlock(inode); | |
562 | return -ENXIO; | |
563 | } | |
564 | ||
565 | blkbits = inode->i_sb->s_blocksize_bits; | |
566 | start = offset >> blkbits; | |
567 | last = start; | |
568 | end = isize >> blkbits; | |
569 | dataoff = offset; | |
570 | ||
571 | do { | |
572 | ret = ext4_get_next_extent(inode, last, end - last + 1, &es); | |
573 | if (ret <= 0) { | |
574 | /* No extent found -> no data */ | |
575 | if (ret == 0) | |
576 | ret = -ENXIO; | |
577 | inode_unlock(inode); | |
578 | return ret; | |
579 | } | |
580 | ||
581 | last = es.es_lblk; | |
582 | if (last != start) | |
583 | dataoff = (loff_t)last << blkbits; | |
584 | if (!ext4_es_is_unwritten(&es)) | |
585 | break; | |
586 | ||
587 | /* | |
588 | * If there is a unwritten extent at this offset, | |
589 | * it will be as a data or a hole according to page | |
590 | * cache that has data or not. | |
591 | */ | |
592 | if (ext4_find_unwritten_pgoff(inode, SEEK_DATA, | |
593 | es.es_lblk + es.es_len, &dataoff)) | |
594 | break; | |
595 | last += es.es_len; | |
596 | dataoff = (loff_t)last << blkbits; | |
597 | cond_resched(); | |
598 | } while (last <= end); | |
599 | ||
600 | inode_unlock(inode); | |
601 | ||
602 | if (dataoff > isize) | |
603 | return -ENXIO; | |
604 | ||
605 | return vfs_setpos(file, dataoff, maxsize); | |
606 | } | |
607 | ||
608 | /* | |
609 | * ext4_seek_hole() retrieves the offset for SEEK_HOLE. | |
610 | */ | |
611 | static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize) | |
612 | { | |
613 | struct inode *inode = file->f_mapping->host; | |
614 | struct extent_status es; | |
615 | ext4_lblk_t start, last, end; | |
616 | loff_t holeoff, isize; | |
617 | int blkbits; | |
618 | int ret; | |
619 | ||
620 | inode_lock(inode); | |
621 | ||
622 | isize = i_size_read(inode); | |
623 | if (offset >= isize) { | |
624 | inode_unlock(inode); | |
625 | return -ENXIO; | |
626 | } | |
627 | ||
628 | blkbits = inode->i_sb->s_blocksize_bits; | |
629 | start = offset >> blkbits; | |
630 | last = start; | |
631 | end = isize >> blkbits; | |
632 | holeoff = offset; | |
633 | ||
634 | do { | |
635 | ret = ext4_get_next_extent(inode, last, end - last + 1, &es); | |
636 | if (ret < 0) { | |
637 | inode_unlock(inode); | |
638 | return ret; | |
639 | } | |
640 | /* Found a hole? */ | |
641 | if (ret == 0 || es.es_lblk > last) { | |
642 | if (last != start) | |
643 | holeoff = (loff_t)last << blkbits; | |
644 | break; | |
645 | } | |
646 | /* | |
647 | * If there is a unwritten extent at this offset, | |
648 | * it will be as a data or a hole according to page | |
649 | * cache that has data or not. | |
650 | */ | |
651 | if (ext4_es_is_unwritten(&es) && | |
652 | ext4_find_unwritten_pgoff(inode, SEEK_HOLE, | |
653 | last + es.es_len, &holeoff)) | |
654 | break; | |
655 | ||
656 | last += es.es_len; | |
657 | holeoff = (loff_t)last << blkbits; | |
658 | cond_resched(); | |
659 | } while (last <= end); | |
660 | ||
661 | inode_unlock(inode); | |
662 | ||
663 | if (holeoff > isize) | |
664 | holeoff = isize; | |
665 | ||
666 | return vfs_setpos(file, holeoff, maxsize); | |
667 | } | |
668 | ||
669 | /* | |
670 | * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values | |
671 | * by calling generic_file_llseek_size() with the appropriate maxbytes | |
672 | * value for each. | |
673 | */ | |
674 | loff_t ext4_llseek(struct file *file, loff_t offset, int whence) | |
675 | { | |
676 | struct inode *inode = file->f_mapping->host; | |
677 | loff_t maxbytes; | |
678 | ||
679 | if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) | |
680 | maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes; | |
681 | else | |
682 | maxbytes = inode->i_sb->s_maxbytes; | |
683 | ||
684 | switch (whence) { | |
685 | case SEEK_SET: | |
686 | case SEEK_CUR: | |
687 | case SEEK_END: | |
688 | return generic_file_llseek_size(file, offset, whence, | |
689 | maxbytes, i_size_read(inode)); | |
690 | case SEEK_DATA: | |
691 | return ext4_seek_data(file, offset, maxbytes); | |
692 | case SEEK_HOLE: | |
693 | return ext4_seek_hole(file, offset, maxbytes); | |
694 | } | |
695 | ||
696 | return -EINVAL; | |
697 | } | |
698 | ||
699 | const struct file_operations ext4_file_operations = { | |
700 | .llseek = ext4_llseek, | |
701 | .read_iter = generic_file_read_iter, | |
702 | .write_iter = ext4_file_write_iter, | |
703 | .unlocked_ioctl = ext4_ioctl, | |
704 | #ifdef CONFIG_COMPAT | |
705 | .compat_ioctl = ext4_compat_ioctl, | |
706 | #endif | |
707 | .mmap = ext4_file_mmap, | |
708 | .open = ext4_file_open, | |
709 | .release = ext4_release_file, | |
710 | .fsync = ext4_sync_file, | |
711 | .splice_read = generic_file_splice_read, | |
712 | .splice_write = iter_file_splice_write, | |
713 | .fallocate = ext4_fallocate, | |
714 | }; | |
715 | ||
716 | const struct inode_operations ext4_file_inode_operations = { | |
717 | .setattr = ext4_setattr, | |
718 | .getattr = ext4_getattr, | |
719 | .setxattr = generic_setxattr, | |
720 | .getxattr = generic_getxattr, | |
721 | .listxattr = ext4_listxattr, | |
722 | .removexattr = generic_removexattr, | |
723 | .get_acl = ext4_get_acl, | |
724 | .set_acl = ext4_set_acl, | |
725 | .fiemap = ext4_fiemap, | |
726 | }; | |
727 |