xref: /linux/fs/nilfs2/inode.c (revision 2174181019e4273e583a0f0a9795e9db38984784)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * NILFS inode operations.
4  *
5  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6  *
7  * Written by Ryusuke Konishi.
8  *
9  */
10 
11 #include <linux/buffer_head.h>
12 #include <linux/gfp.h>
13 #include <linux/mpage.h>
14 #include <linux/pagemap.h>
15 #include <linux/writeback.h>
16 #include <linux/uio.h>
17 #include <linux/fiemap.h>
18 #include "nilfs.h"
19 #include "btnode.h"
20 #include "segment.h"
21 #include "page.h"
22 #include "mdt.h"
23 #include "cpfile.h"
24 #include "ifile.h"
25 
26 /**
27  * struct nilfs_iget_args - arguments used during comparison between inodes
28  * @ino: inode number
29  * @cno: checkpoint number
30  * @root: pointer on NILFS root object (mounted checkpoint)
31  * @for_gc: inode for GC flag
32  * @for_btnc: inode for B-tree node cache flag
33  * @for_shadow: inode for shadowed page cache flag
34  */
35 struct nilfs_iget_args {
36 	u64 ino;
37 	__u64 cno;
38 	struct nilfs_root *root;
39 	bool for_gc;
40 	bool for_btnc;
41 	bool for_shadow;
42 };
43 
44 static int nilfs_iget_test(struct inode *inode, void *opaque);
45 
46 void nilfs_inode_add_blocks(struct inode *inode, int n)
47 {
48 	struct nilfs_root *root = NILFS_I(inode)->i_root;
49 
50 	inode_add_bytes(inode, i_blocksize(inode) * n);
51 	if (root)
52 		atomic64_add(n, &root->blocks_count);
53 }
54 
55 void nilfs_inode_sub_blocks(struct inode *inode, int n)
56 {
57 	struct nilfs_root *root = NILFS_I(inode)->i_root;
58 
59 	inode_sub_bytes(inode, i_blocksize(inode) * n);
60 	if (root)
61 		atomic64_sub(n, &root->blocks_count);
62 }
63 
64 /**
65  * nilfs_get_block() - get a file block on the filesystem (callback function)
66  * @inode: inode struct of the target file
67  * @blkoff: file block number
68  * @bh_result: buffer head to be mapped on
69  * @create: indicate whether allocating the block or not when it has not
70  *      been allocated yet.
71  *
72  * This function does not issue actual read request of the specified data
73  * block. It is done by VFS.
74  */
75 int nilfs_get_block(struct inode *inode, sector_t blkoff,
76 		    struct buffer_head *bh_result, int create)
77 {
78 	struct nilfs_inode_info *ii = NILFS_I(inode);
79 	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
80 	__u64 blknum = 0;
81 	int err = 0, ret;
82 	unsigned int maxblocks = bh_result->b_size >> inode->i_blkbits;
83 
84 	down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
85 	ret = nilfs_bmap_lookup_contig(ii->i_bmap, blkoff, &blknum, maxblocks);
86 	up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
87 	if (ret >= 0) {	/* found */
88 		map_bh(bh_result, inode->i_sb, blknum);
89 		if (ret > 0)
90 			bh_result->b_size = (ret << inode->i_blkbits);
91 		goto out;
92 	}
93 	/* data block was not found */
94 	if (ret == -ENOENT && create) {
95 		struct nilfs_transaction_info ti;
96 
97 		bh_result->b_blocknr = 0;
98 		err = nilfs_transaction_begin(inode->i_sb, &ti, 1);
99 		if (unlikely(err))
100 			goto out;
101 		err = nilfs_bmap_insert(ii->i_bmap, blkoff,
102 					(unsigned long)bh_result);
103 		if (unlikely(err != 0)) {
104 			if (err == -EEXIST) {
105 				/*
106 				 * The get_block() function could be called
107 				 * from multiple callers for an inode.
108 				 * However, the page having this block must
109 				 * be locked in this case.
110 				 */
111 				nilfs_warn(inode->i_sb,
112 					   "%s (ino=%lu): a race condition while inserting a data block at offset=%llu",
113 					   __func__, inode->i_ino,
114 					   (unsigned long long)blkoff);
115 				err = 0;
116 			}
117 			nilfs_transaction_abort(inode->i_sb);
118 			goto out;
119 		}
120 		nilfs_mark_inode_dirty_sync(inode);
121 		nilfs_transaction_commit(inode->i_sb); /* never fails */
122 		/* Error handling should be detailed */
123 		set_buffer_new(bh_result);
124 		set_buffer_delay(bh_result);
125 		map_bh(bh_result, inode->i_sb, 0);
126 		/* Disk block number must be changed to proper value */
127 
128 	} else if (ret == -ENOENT) {
129 		/*
130 		 * not found is not error (e.g. hole); must return without
131 		 * the mapped state flag.
132 		 */
133 		;
134 	} else {
135 		err = ret;
136 	}
137 
138  out:
139 	return err;
140 }
141 
142 /**
143  * nilfs_read_folio() - implement read_folio() method of nilfs_aops {}
144  * address_space_operations.
145  * @file: file struct of the file to be read
146  * @folio: the folio to be read
147  */
148 static int nilfs_read_folio(struct file *file, struct folio *folio)
149 {
150 	return mpage_read_folio(folio, nilfs_get_block);
151 }
152 
153 static void nilfs_readahead(struct readahead_control *rac)
154 {
155 	mpage_readahead(rac, nilfs_get_block);
156 }
157 
158 static int nilfs_writepages(struct address_space *mapping,
159 			    struct writeback_control *wbc)
160 {
161 	struct inode *inode = mapping->host;
162 	int err = 0;
163 
164 	if (sb_rdonly(inode->i_sb)) {
165 		nilfs_clear_dirty_pages(mapping, false);
166 		return -EROFS;
167 	}
168 
169 	if (wbc->sync_mode == WB_SYNC_ALL)
170 		err = nilfs_construct_dsync_segment(inode->i_sb, inode,
171 						    wbc->range_start,
172 						    wbc->range_end);
173 	return err;
174 }
175 
176 static int nilfs_writepage(struct page *page, struct writeback_control *wbc)
177 {
178 	struct inode *inode = page->mapping->host;
179 	int err;
180 
181 	if (sb_rdonly(inode->i_sb)) {
182 		/*
183 		 * It means that filesystem was remounted in read-only
184 		 * mode because of error or metadata corruption. But we
185 		 * have dirty pages that try to be flushed in background.
186 		 * So, here we simply discard this dirty page.
187 		 */
188 		nilfs_clear_dirty_page(page, false);
189 		unlock_page(page);
190 		return -EROFS;
191 	}
192 
193 	redirty_page_for_writepage(wbc, page);
194 	unlock_page(page);
195 
196 	if (wbc->sync_mode == WB_SYNC_ALL) {
197 		err = nilfs_construct_segment(inode->i_sb);
198 		if (unlikely(err))
199 			return err;
200 	} else if (wbc->for_reclaim)
201 		nilfs_flush_segment(inode->i_sb, inode->i_ino);
202 
203 	return 0;
204 }
205 
206 static bool nilfs_dirty_folio(struct address_space *mapping,
207 		struct folio *folio)
208 {
209 	struct inode *inode = mapping->host;
210 	struct buffer_head *head;
211 	unsigned int nr_dirty = 0;
212 	bool ret = filemap_dirty_folio(mapping, folio);
213 
214 	/*
215 	 * The page may not be locked, eg if called from try_to_unmap_one()
216 	 */
217 	spin_lock(&mapping->private_lock);
218 	head = folio_buffers(folio);
219 	if (head) {
220 		struct buffer_head *bh = head;
221 
222 		do {
223 			/* Do not mark hole blocks dirty */
224 			if (buffer_dirty(bh) || !buffer_mapped(bh))
225 				continue;
226 
227 			set_buffer_dirty(bh);
228 			nr_dirty++;
229 		} while (bh = bh->b_this_page, bh != head);
230 	} else if (ret) {
231 		nr_dirty = 1 << (folio_shift(folio) - inode->i_blkbits);
232 	}
233 	spin_unlock(&mapping->private_lock);
234 
235 	if (nr_dirty)
236 		nilfs_set_file_dirty(inode, nr_dirty);
237 	return ret;
238 }
239 
240 void nilfs_write_failed(struct address_space *mapping, loff_t to)
241 {
242 	struct inode *inode = mapping->host;
243 
244 	if (to > inode->i_size) {
245 		truncate_pagecache(inode, inode->i_size);
246 		nilfs_truncate(inode);
247 	}
248 }
249 
250 static int nilfs_write_begin(struct file *file, struct address_space *mapping,
251 			     loff_t pos, unsigned len,
252 			     struct page **pagep, void **fsdata)
253 
254 {
255 	struct inode *inode = mapping->host;
256 	int err = nilfs_transaction_begin(inode->i_sb, NULL, 1);
257 
258 	if (unlikely(err))
259 		return err;
260 
261 	err = block_write_begin(mapping, pos, len, pagep, nilfs_get_block);
262 	if (unlikely(err)) {
263 		nilfs_write_failed(mapping, pos + len);
264 		nilfs_transaction_abort(inode->i_sb);
265 	}
266 	return err;
267 }
268 
269 static int nilfs_write_end(struct file *file, struct address_space *mapping,
270 			   loff_t pos, unsigned len, unsigned copied,
271 			   struct page *page, void *fsdata)
272 {
273 	struct inode *inode = mapping->host;
274 	unsigned int start = pos & (PAGE_SIZE - 1);
275 	unsigned int nr_dirty;
276 	int err;
277 
278 	nr_dirty = nilfs_page_count_clean_buffers(page, start,
279 						  start + copied);
280 	copied = generic_write_end(file, mapping, pos, len, copied, page,
281 				   fsdata);
282 	nilfs_set_file_dirty(inode, nr_dirty);
283 	err = nilfs_transaction_commit(inode->i_sb);
284 	return err ? : copied;
285 }
286 
287 static ssize_t
288 nilfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
289 {
290 	struct inode *inode = file_inode(iocb->ki_filp);
291 
292 	if (iov_iter_rw(iter) == WRITE)
293 		return 0;
294 
295 	/* Needs synchronization with the cleaner */
296 	return blockdev_direct_IO(iocb, inode, iter, nilfs_get_block);
297 }
298 
299 const struct address_space_operations nilfs_aops = {
300 	.writepage		= nilfs_writepage,
301 	.read_folio		= nilfs_read_folio,
302 	.writepages		= nilfs_writepages,
303 	.dirty_folio		= nilfs_dirty_folio,
304 	.readahead		= nilfs_readahead,
305 	.write_begin		= nilfs_write_begin,
306 	.write_end		= nilfs_write_end,
307 	.invalidate_folio	= block_invalidate_folio,
308 	.direct_IO		= nilfs_direct_IO,
309 	.is_partially_uptodate  = block_is_partially_uptodate,
310 };
311 
312 static int nilfs_insert_inode_locked(struct inode *inode,
313 				     struct nilfs_root *root,
314 				     unsigned long ino)
315 {
316 	struct nilfs_iget_args args = {
317 		.ino = ino, .root = root, .cno = 0, .for_gc = false,
318 		.for_btnc = false, .for_shadow = false
319 	};
320 
321 	return insert_inode_locked4(inode, ino, nilfs_iget_test, &args);
322 }
323 
324 struct inode *nilfs_new_inode(struct inode *dir, umode_t mode)
325 {
326 	struct super_block *sb = dir->i_sb;
327 	struct the_nilfs *nilfs = sb->s_fs_info;
328 	struct inode *inode;
329 	struct nilfs_inode_info *ii;
330 	struct nilfs_root *root;
331 	struct buffer_head *bh;
332 	int err = -ENOMEM;
333 	ino_t ino;
334 
335 	inode = new_inode(sb);
336 	if (unlikely(!inode))
337 		goto failed;
338 
339 	mapping_set_gfp_mask(inode->i_mapping,
340 			   mapping_gfp_constraint(inode->i_mapping, ~__GFP_FS));
341 
342 	root = NILFS_I(dir)->i_root;
343 	ii = NILFS_I(inode);
344 	ii->i_state = BIT(NILFS_I_NEW);
345 	ii->i_root = root;
346 
347 	err = nilfs_ifile_create_inode(root->ifile, &ino, &bh);
348 	if (unlikely(err))
349 		goto failed_ifile_create_inode;
350 	/* reference count of i_bh inherits from nilfs_mdt_read_block() */
351 
352 	if (unlikely(ino < NILFS_USER_INO)) {
353 		nilfs_warn(sb,
354 			   "inode bitmap is inconsistent for reserved inodes");
355 		do {
356 			brelse(bh);
357 			err = nilfs_ifile_create_inode(root->ifile, &ino, &bh);
358 			if (unlikely(err))
359 				goto failed_ifile_create_inode;
360 		} while (ino < NILFS_USER_INO);
361 
362 		nilfs_info(sb, "repaired inode bitmap for reserved inodes");
363 	}
364 	ii->i_bh = bh;
365 
366 	atomic64_inc(&root->inodes_count);
367 	inode_init_owner(&nop_mnt_idmap, inode, dir, mode);
368 	inode->i_ino = ino;
369 	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
370 
371 	if (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)) {
372 		err = nilfs_bmap_read(ii->i_bmap, NULL);
373 		if (err < 0)
374 			goto failed_after_creation;
375 
376 		set_bit(NILFS_I_BMAP, &ii->i_state);
377 		/* No lock is needed; iget() ensures it. */
378 	}
379 
380 	ii->i_flags = nilfs_mask_flags(
381 		mode, NILFS_I(dir)->i_flags & NILFS_FL_INHERITED);
382 
383 	/* ii->i_file_acl = 0; */
384 	/* ii->i_dir_acl = 0; */
385 	ii->i_dir_start_lookup = 0;
386 	nilfs_set_inode_flags(inode);
387 	spin_lock(&nilfs->ns_next_gen_lock);
388 	inode->i_generation = nilfs->ns_next_generation++;
389 	spin_unlock(&nilfs->ns_next_gen_lock);
390 	if (nilfs_insert_inode_locked(inode, root, ino) < 0) {
391 		err = -EIO;
392 		goto failed_after_creation;
393 	}
394 
395 	err = nilfs_init_acl(inode, dir);
396 	if (unlikely(err))
397 		/*
398 		 * Never occur.  When supporting nilfs_init_acl(),
399 		 * proper cancellation of above jobs should be considered.
400 		 */
401 		goto failed_after_creation;
402 
403 	return inode;
404 
405  failed_after_creation:
406 	clear_nlink(inode);
407 	if (inode->i_state & I_NEW)
408 		unlock_new_inode(inode);
409 	iput(inode);  /*
410 		       * raw_inode will be deleted through
411 		       * nilfs_evict_inode().
412 		       */
413 	goto failed;
414 
415  failed_ifile_create_inode:
416 	make_bad_inode(inode);
417 	iput(inode);
418  failed:
419 	return ERR_PTR(err);
420 }
421 
422 void nilfs_set_inode_flags(struct inode *inode)
423 {
424 	unsigned int flags = NILFS_I(inode)->i_flags;
425 	unsigned int new_fl = 0;
426 
427 	if (flags & FS_SYNC_FL)
428 		new_fl |= S_SYNC;
429 	if (flags & FS_APPEND_FL)
430 		new_fl |= S_APPEND;
431 	if (flags & FS_IMMUTABLE_FL)
432 		new_fl |= S_IMMUTABLE;
433 	if (flags & FS_NOATIME_FL)
434 		new_fl |= S_NOATIME;
435 	if (flags & FS_DIRSYNC_FL)
436 		new_fl |= S_DIRSYNC;
437 	inode_set_flags(inode, new_fl, S_SYNC | S_APPEND | S_IMMUTABLE |
438 			S_NOATIME | S_DIRSYNC);
439 }
440 
441 int nilfs_read_inode_common(struct inode *inode,
442 			    struct nilfs_inode *raw_inode)
443 {
444 	struct nilfs_inode_info *ii = NILFS_I(inode);
445 	int err;
446 
447 	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
448 	i_uid_write(inode, le32_to_cpu(raw_inode->i_uid));
449 	i_gid_write(inode, le32_to_cpu(raw_inode->i_gid));
450 	set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
451 	inode->i_size = le64_to_cpu(raw_inode->i_size);
452 	inode->i_atime.tv_sec = le64_to_cpu(raw_inode->i_mtime);
453 	inode->i_ctime.tv_sec = le64_to_cpu(raw_inode->i_ctime);
454 	inode->i_mtime.tv_sec = le64_to_cpu(raw_inode->i_mtime);
455 	inode->i_atime.tv_nsec = le32_to_cpu(raw_inode->i_mtime_nsec);
456 	inode->i_ctime.tv_nsec = le32_to_cpu(raw_inode->i_ctime_nsec);
457 	inode->i_mtime.tv_nsec = le32_to_cpu(raw_inode->i_mtime_nsec);
458 	if (nilfs_is_metadata_file_inode(inode) && !S_ISREG(inode->i_mode))
459 		return -EIO; /* this inode is for metadata and corrupted */
460 	if (inode->i_nlink == 0)
461 		return -ESTALE; /* this inode is deleted */
462 
463 	inode->i_blocks = le64_to_cpu(raw_inode->i_blocks);
464 	ii->i_flags = le32_to_cpu(raw_inode->i_flags);
465 #if 0
466 	ii->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
467 	ii->i_dir_acl = S_ISREG(inode->i_mode) ?
468 		0 : le32_to_cpu(raw_inode->i_dir_acl);
469 #endif
470 	ii->i_dir_start_lookup = 0;
471 	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
472 
473 	if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
474 	    S_ISLNK(inode->i_mode)) {
475 		err = nilfs_bmap_read(ii->i_bmap, raw_inode);
476 		if (err < 0)
477 			return err;
478 		set_bit(NILFS_I_BMAP, &ii->i_state);
479 		/* No lock is needed; iget() ensures it. */
480 	}
481 	return 0;
482 }
483 
484 static int __nilfs_read_inode(struct super_block *sb,
485 			      struct nilfs_root *root, unsigned long ino,
486 			      struct inode *inode)
487 {
488 	struct the_nilfs *nilfs = sb->s_fs_info;
489 	struct buffer_head *bh;
490 	struct nilfs_inode *raw_inode;
491 	int err;
492 
493 	down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
494 	err = nilfs_ifile_get_inode_block(root->ifile, ino, &bh);
495 	if (unlikely(err))
496 		goto bad_inode;
497 
498 	raw_inode = nilfs_ifile_map_inode(root->ifile, ino, bh);
499 
500 	err = nilfs_read_inode_common(inode, raw_inode);
501 	if (err)
502 		goto failed_unmap;
503 
504 	if (S_ISREG(inode->i_mode)) {
505 		inode->i_op = &nilfs_file_inode_operations;
506 		inode->i_fop = &nilfs_file_operations;
507 		inode->i_mapping->a_ops = &nilfs_aops;
508 	} else if (S_ISDIR(inode->i_mode)) {
509 		inode->i_op = &nilfs_dir_inode_operations;
510 		inode->i_fop = &nilfs_dir_operations;
511 		inode->i_mapping->a_ops = &nilfs_aops;
512 	} else if (S_ISLNK(inode->i_mode)) {
513 		inode->i_op = &nilfs_symlink_inode_operations;
514 		inode_nohighmem(inode);
515 		inode->i_mapping->a_ops = &nilfs_aops;
516 	} else {
517 		inode->i_op = &nilfs_special_inode_operations;
518 		init_special_inode(
519 			inode, inode->i_mode,
520 			huge_decode_dev(le64_to_cpu(raw_inode->i_device_code)));
521 	}
522 	nilfs_ifile_unmap_inode(root->ifile, ino, bh);
523 	brelse(bh);
524 	up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
525 	nilfs_set_inode_flags(inode);
526 	mapping_set_gfp_mask(inode->i_mapping,
527 			   mapping_gfp_constraint(inode->i_mapping, ~__GFP_FS));
528 	return 0;
529 
530  failed_unmap:
531 	nilfs_ifile_unmap_inode(root->ifile, ino, bh);
532 	brelse(bh);
533 
534  bad_inode:
535 	up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
536 	return err;
537 }
538 
539 static int nilfs_iget_test(struct inode *inode, void *opaque)
540 {
541 	struct nilfs_iget_args *args = opaque;
542 	struct nilfs_inode_info *ii;
543 
544 	if (args->ino != inode->i_ino || args->root != NILFS_I(inode)->i_root)
545 		return 0;
546 
547 	ii = NILFS_I(inode);
548 	if (test_bit(NILFS_I_BTNC, &ii->i_state)) {
549 		if (!args->for_btnc)
550 			return 0;
551 	} else if (args->for_btnc) {
552 		return 0;
553 	}
554 	if (test_bit(NILFS_I_SHADOW, &ii->i_state)) {
555 		if (!args->for_shadow)
556 			return 0;
557 	} else if (args->for_shadow) {
558 		return 0;
559 	}
560 
561 	if (!test_bit(NILFS_I_GCINODE, &ii->i_state))
562 		return !args->for_gc;
563 
564 	return args->for_gc && args->cno == ii->i_cno;
565 }
566 
567 static int nilfs_iget_set(struct inode *inode, void *opaque)
568 {
569 	struct nilfs_iget_args *args = opaque;
570 
571 	inode->i_ino = args->ino;
572 	NILFS_I(inode)->i_cno = args->cno;
573 	NILFS_I(inode)->i_root = args->root;
574 	if (args->root && args->ino == NILFS_ROOT_INO)
575 		nilfs_get_root(args->root);
576 
577 	if (args->for_gc)
578 		NILFS_I(inode)->i_state = BIT(NILFS_I_GCINODE);
579 	if (args->for_btnc)
580 		NILFS_I(inode)->i_state |= BIT(NILFS_I_BTNC);
581 	if (args->for_shadow)
582 		NILFS_I(inode)->i_state |= BIT(NILFS_I_SHADOW);
583 	return 0;
584 }
585 
586 struct inode *nilfs_ilookup(struct super_block *sb, struct nilfs_root *root,
587 			    unsigned long ino)
588 {
589 	struct nilfs_iget_args args = {
590 		.ino = ino, .root = root, .cno = 0, .for_gc = false,
591 		.for_btnc = false, .for_shadow = false
592 	};
593 
594 	return ilookup5(sb, ino, nilfs_iget_test, &args);
595 }
596 
597 struct inode *nilfs_iget_locked(struct super_block *sb, struct nilfs_root *root,
598 				unsigned long ino)
599 {
600 	struct nilfs_iget_args args = {
601 		.ino = ino, .root = root, .cno = 0, .for_gc = false,
602 		.for_btnc = false, .for_shadow = false
603 	};
604 
605 	return iget5_locked(sb, ino, nilfs_iget_test, nilfs_iget_set, &args);
606 }
607 
608 struct inode *nilfs_iget(struct super_block *sb, struct nilfs_root *root,
609 			 unsigned long ino)
610 {
611 	struct inode *inode;
612 	int err;
613 
614 	inode = nilfs_iget_locked(sb, root, ino);
615 	if (unlikely(!inode))
616 		return ERR_PTR(-ENOMEM);
617 	if (!(inode->i_state & I_NEW))
618 		return inode;
619 
620 	err = __nilfs_read_inode(sb, root, ino, inode);
621 	if (unlikely(err)) {
622 		iget_failed(inode);
623 		return ERR_PTR(err);
624 	}
625 	unlock_new_inode(inode);
626 	return inode;
627 }
628 
629 struct inode *nilfs_iget_for_gc(struct super_block *sb, unsigned long ino,
630 				__u64 cno)
631 {
632 	struct nilfs_iget_args args = {
633 		.ino = ino, .root = NULL, .cno = cno, .for_gc = true,
634 		.for_btnc = false, .for_shadow = false
635 	};
636 	struct inode *inode;
637 	int err;
638 
639 	inode = iget5_locked(sb, ino, nilfs_iget_test, nilfs_iget_set, &args);
640 	if (unlikely(!inode))
641 		return ERR_PTR(-ENOMEM);
642 	if (!(inode->i_state & I_NEW))
643 		return inode;
644 
645 	err = nilfs_init_gcinode(inode);
646 	if (unlikely(err)) {
647 		iget_failed(inode);
648 		return ERR_PTR(err);
649 	}
650 	unlock_new_inode(inode);
651 	return inode;
652 }
653 
654 /**
655  * nilfs_attach_btree_node_cache - attach a B-tree node cache to the inode
656  * @inode: inode object
657  *
658  * nilfs_attach_btree_node_cache() attaches a B-tree node cache to @inode,
659  * or does nothing if the inode already has it.  This function allocates
660  * an additional inode to maintain page cache of B-tree nodes one-on-one.
661  *
662  * Return Value: On success, 0 is returned. On errors, one of the following
663  * negative error code is returned.
664  *
665  * %-ENOMEM - Insufficient memory available.
666  */
667 int nilfs_attach_btree_node_cache(struct inode *inode)
668 {
669 	struct nilfs_inode_info *ii = NILFS_I(inode);
670 	struct inode *btnc_inode;
671 	struct nilfs_iget_args args;
672 
673 	if (ii->i_assoc_inode)
674 		return 0;
675 
676 	args.ino = inode->i_ino;
677 	args.root = ii->i_root;
678 	args.cno = ii->i_cno;
679 	args.for_gc = test_bit(NILFS_I_GCINODE, &ii->i_state) != 0;
680 	args.for_btnc = true;
681 	args.for_shadow = test_bit(NILFS_I_SHADOW, &ii->i_state) != 0;
682 
683 	btnc_inode = iget5_locked(inode->i_sb, inode->i_ino, nilfs_iget_test,
684 				  nilfs_iget_set, &args);
685 	if (unlikely(!btnc_inode))
686 		return -ENOMEM;
687 	if (btnc_inode->i_state & I_NEW) {
688 		nilfs_init_btnc_inode(btnc_inode);
689 		unlock_new_inode(btnc_inode);
690 	}
691 	NILFS_I(btnc_inode)->i_assoc_inode = inode;
692 	NILFS_I(btnc_inode)->i_bmap = ii->i_bmap;
693 	ii->i_assoc_inode = btnc_inode;
694 
695 	return 0;
696 }
697 
698 /**
699  * nilfs_detach_btree_node_cache - detach the B-tree node cache from the inode
700  * @inode: inode object
701  *
702  * nilfs_detach_btree_node_cache() detaches the B-tree node cache and its
703  * holder inode bound to @inode, or does nothing if @inode doesn't have it.
704  */
705 void nilfs_detach_btree_node_cache(struct inode *inode)
706 {
707 	struct nilfs_inode_info *ii = NILFS_I(inode);
708 	struct inode *btnc_inode = ii->i_assoc_inode;
709 
710 	if (btnc_inode) {
711 		NILFS_I(btnc_inode)->i_assoc_inode = NULL;
712 		ii->i_assoc_inode = NULL;
713 		iput(btnc_inode);
714 	}
715 }
716 
717 /**
718  * nilfs_iget_for_shadow - obtain inode for shadow mapping
719  * @inode: inode object that uses shadow mapping
720  *
721  * nilfs_iget_for_shadow() allocates a pair of inodes that holds page
722  * caches for shadow mapping.  The page cache for data pages is set up
723  * in one inode and the one for b-tree node pages is set up in the
724  * other inode, which is attached to the former inode.
725  *
726  * Return Value: On success, a pointer to the inode for data pages is
727  * returned. On errors, one of the following negative error code is returned
728  * in a pointer type.
729  *
730  * %-ENOMEM - Insufficient memory available.
731  */
732 struct inode *nilfs_iget_for_shadow(struct inode *inode)
733 {
734 	struct nilfs_iget_args args = {
735 		.ino = inode->i_ino, .root = NULL, .cno = 0, .for_gc = false,
736 		.for_btnc = false, .for_shadow = true
737 	};
738 	struct inode *s_inode;
739 	int err;
740 
741 	s_inode = iget5_locked(inode->i_sb, inode->i_ino, nilfs_iget_test,
742 			       nilfs_iget_set, &args);
743 	if (unlikely(!s_inode))
744 		return ERR_PTR(-ENOMEM);
745 	if (!(s_inode->i_state & I_NEW))
746 		return inode;
747 
748 	NILFS_I(s_inode)->i_flags = 0;
749 	memset(NILFS_I(s_inode)->i_bmap, 0, sizeof(struct nilfs_bmap));
750 	mapping_set_gfp_mask(s_inode->i_mapping, GFP_NOFS);
751 
752 	err = nilfs_attach_btree_node_cache(s_inode);
753 	if (unlikely(err)) {
754 		iget_failed(s_inode);
755 		return ERR_PTR(err);
756 	}
757 	unlock_new_inode(s_inode);
758 	return s_inode;
759 }
760 
761 void nilfs_write_inode_common(struct inode *inode,
762 			      struct nilfs_inode *raw_inode, int has_bmap)
763 {
764 	struct nilfs_inode_info *ii = NILFS_I(inode);
765 
766 	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
767 	raw_inode->i_uid = cpu_to_le32(i_uid_read(inode));
768 	raw_inode->i_gid = cpu_to_le32(i_gid_read(inode));
769 	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
770 	raw_inode->i_size = cpu_to_le64(inode->i_size);
771 	raw_inode->i_ctime = cpu_to_le64(inode->i_ctime.tv_sec);
772 	raw_inode->i_mtime = cpu_to_le64(inode->i_mtime.tv_sec);
773 	raw_inode->i_ctime_nsec = cpu_to_le32(inode->i_ctime.tv_nsec);
774 	raw_inode->i_mtime_nsec = cpu_to_le32(inode->i_mtime.tv_nsec);
775 	raw_inode->i_blocks = cpu_to_le64(inode->i_blocks);
776 
777 	raw_inode->i_flags = cpu_to_le32(ii->i_flags);
778 	raw_inode->i_generation = cpu_to_le32(inode->i_generation);
779 
780 	if (NILFS_ROOT_METADATA_FILE(inode->i_ino)) {
781 		struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
782 
783 		/* zero-fill unused portion in the case of super root block */
784 		raw_inode->i_xattr = 0;
785 		raw_inode->i_pad = 0;
786 		memset((void *)raw_inode + sizeof(*raw_inode), 0,
787 		       nilfs->ns_inode_size - sizeof(*raw_inode));
788 	}
789 
790 	if (has_bmap)
791 		nilfs_bmap_write(ii->i_bmap, raw_inode);
792 	else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
793 		raw_inode->i_device_code =
794 			cpu_to_le64(huge_encode_dev(inode->i_rdev));
795 	/*
796 	 * When extending inode, nilfs->ns_inode_size should be checked
797 	 * for substitutions of appended fields.
798 	 */
799 }
800 
801 void nilfs_update_inode(struct inode *inode, struct buffer_head *ibh, int flags)
802 {
803 	ino_t ino = inode->i_ino;
804 	struct nilfs_inode_info *ii = NILFS_I(inode);
805 	struct inode *ifile = ii->i_root->ifile;
806 	struct nilfs_inode *raw_inode;
807 
808 	raw_inode = nilfs_ifile_map_inode(ifile, ino, ibh);
809 
810 	if (test_and_clear_bit(NILFS_I_NEW, &ii->i_state))
811 		memset(raw_inode, 0, NILFS_MDT(ifile)->mi_entry_size);
812 	if (flags & I_DIRTY_DATASYNC)
813 		set_bit(NILFS_I_INODE_SYNC, &ii->i_state);
814 
815 	nilfs_write_inode_common(inode, raw_inode, 0);
816 		/*
817 		 * XXX: call with has_bmap = 0 is a workaround to avoid
818 		 * deadlock of bmap.  This delays update of i_bmap to just
819 		 * before writing.
820 		 */
821 
822 	nilfs_ifile_unmap_inode(ifile, ino, ibh);
823 }
824 
825 #define NILFS_MAX_TRUNCATE_BLOCKS	16384  /* 64MB for 4KB block */
826 
827 static void nilfs_truncate_bmap(struct nilfs_inode_info *ii,
828 				unsigned long from)
829 {
830 	__u64 b;
831 	int ret;
832 
833 	if (!test_bit(NILFS_I_BMAP, &ii->i_state))
834 		return;
835 repeat:
836 	ret = nilfs_bmap_last_key(ii->i_bmap, &b);
837 	if (ret == -ENOENT)
838 		return;
839 	else if (ret < 0)
840 		goto failed;
841 
842 	if (b < from)
843 		return;
844 
845 	b -= min_t(__u64, NILFS_MAX_TRUNCATE_BLOCKS, b - from);
846 	ret = nilfs_bmap_truncate(ii->i_bmap, b);
847 	nilfs_relax_pressure_in_lock(ii->vfs_inode.i_sb);
848 	if (!ret || (ret == -ENOMEM &&
849 		     nilfs_bmap_truncate(ii->i_bmap, b) == 0))
850 		goto repeat;
851 
852 failed:
853 	nilfs_warn(ii->vfs_inode.i_sb, "error %d truncating bmap (ino=%lu)",
854 		   ret, ii->vfs_inode.i_ino);
855 }
856 
857 void nilfs_truncate(struct inode *inode)
858 {
859 	unsigned long blkoff;
860 	unsigned int blocksize;
861 	struct nilfs_transaction_info ti;
862 	struct super_block *sb = inode->i_sb;
863 	struct nilfs_inode_info *ii = NILFS_I(inode);
864 
865 	if (!test_bit(NILFS_I_BMAP, &ii->i_state))
866 		return;
867 	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
868 		return;
869 
870 	blocksize = sb->s_blocksize;
871 	blkoff = (inode->i_size + blocksize - 1) >> sb->s_blocksize_bits;
872 	nilfs_transaction_begin(sb, &ti, 0); /* never fails */
873 
874 	block_truncate_page(inode->i_mapping, inode->i_size, nilfs_get_block);
875 
876 	nilfs_truncate_bmap(ii, blkoff);
877 
878 	inode->i_mtime = inode->i_ctime = current_time(inode);
879 	if (IS_SYNC(inode))
880 		nilfs_set_transaction_flag(NILFS_TI_SYNC);
881 
882 	nilfs_mark_inode_dirty(inode);
883 	nilfs_set_file_dirty(inode, 0);
884 	nilfs_transaction_commit(sb);
885 	/*
886 	 * May construct a logical segment and may fail in sync mode.
887 	 * But truncate has no return value.
888 	 */
889 }
890 
891 static void nilfs_clear_inode(struct inode *inode)
892 {
893 	struct nilfs_inode_info *ii = NILFS_I(inode);
894 
895 	/*
896 	 * Free resources allocated in nilfs_read_inode(), here.
897 	 */
898 	BUG_ON(!list_empty(&ii->i_dirty));
899 	brelse(ii->i_bh);
900 	ii->i_bh = NULL;
901 
902 	if (nilfs_is_metadata_file_inode(inode))
903 		nilfs_mdt_clear(inode);
904 
905 	if (test_bit(NILFS_I_BMAP, &ii->i_state))
906 		nilfs_bmap_clear(ii->i_bmap);
907 
908 	if (!test_bit(NILFS_I_BTNC, &ii->i_state))
909 		nilfs_detach_btree_node_cache(inode);
910 
911 	if (ii->i_root && inode->i_ino == NILFS_ROOT_INO)
912 		nilfs_put_root(ii->i_root);
913 }
914 
915 void nilfs_evict_inode(struct inode *inode)
916 {
917 	struct nilfs_transaction_info ti;
918 	struct super_block *sb = inode->i_sb;
919 	struct nilfs_inode_info *ii = NILFS_I(inode);
920 	struct the_nilfs *nilfs;
921 	int ret;
922 
923 	if (inode->i_nlink || !ii->i_root || unlikely(is_bad_inode(inode))) {
924 		truncate_inode_pages_final(&inode->i_data);
925 		clear_inode(inode);
926 		nilfs_clear_inode(inode);
927 		return;
928 	}
929 	nilfs_transaction_begin(sb, &ti, 0); /* never fails */
930 
931 	truncate_inode_pages_final(&inode->i_data);
932 
933 	nilfs = sb->s_fs_info;
934 	if (unlikely(sb_rdonly(sb) || !nilfs->ns_writer)) {
935 		/*
936 		 * If this inode is about to be disposed after the file system
937 		 * has been degraded to read-only due to file system corruption
938 		 * or after the writer has been detached, do not make any
939 		 * changes that cause writes, just clear it.
940 		 * Do this check after read-locking ns_segctor_sem by
941 		 * nilfs_transaction_begin() in order to avoid a race with
942 		 * the writer detach operation.
943 		 */
944 		clear_inode(inode);
945 		nilfs_clear_inode(inode);
946 		nilfs_transaction_abort(sb);
947 		return;
948 	}
949 
950 	/* TODO: some of the following operations may fail.  */
951 	nilfs_truncate_bmap(ii, 0);
952 	nilfs_mark_inode_dirty(inode);
953 	clear_inode(inode);
954 
955 	ret = nilfs_ifile_delete_inode(ii->i_root->ifile, inode->i_ino);
956 	if (!ret)
957 		atomic64_dec(&ii->i_root->inodes_count);
958 
959 	nilfs_clear_inode(inode);
960 
961 	if (IS_SYNC(inode))
962 		nilfs_set_transaction_flag(NILFS_TI_SYNC);
963 	nilfs_transaction_commit(sb);
964 	/*
965 	 * May construct a logical segment and may fail in sync mode.
966 	 * But delete_inode has no return value.
967 	 */
968 }
969 
970 int nilfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
971 		  struct iattr *iattr)
972 {
973 	struct nilfs_transaction_info ti;
974 	struct inode *inode = d_inode(dentry);
975 	struct super_block *sb = inode->i_sb;
976 	int err;
977 
978 	err = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
979 	if (err)
980 		return err;
981 
982 	err = nilfs_transaction_begin(sb, &ti, 0);
983 	if (unlikely(err))
984 		return err;
985 
986 	if ((iattr->ia_valid & ATTR_SIZE) &&
987 	    iattr->ia_size != i_size_read(inode)) {
988 		inode_dio_wait(inode);
989 		truncate_setsize(inode, iattr->ia_size);
990 		nilfs_truncate(inode);
991 	}
992 
993 	setattr_copy(&nop_mnt_idmap, inode, iattr);
994 	mark_inode_dirty(inode);
995 
996 	if (iattr->ia_valid & ATTR_MODE) {
997 		err = nilfs_acl_chmod(inode);
998 		if (unlikely(err))
999 			goto out_err;
1000 	}
1001 
1002 	return nilfs_transaction_commit(sb);
1003 
1004 out_err:
1005 	nilfs_transaction_abort(sb);
1006 	return err;
1007 }
1008 
1009 int nilfs_permission(struct mnt_idmap *idmap, struct inode *inode,
1010 		     int mask)
1011 {
1012 	struct nilfs_root *root = NILFS_I(inode)->i_root;
1013 
1014 	if ((mask & MAY_WRITE) && root &&
1015 	    root->cno != NILFS_CPTREE_CURRENT_CNO)
1016 		return -EROFS; /* snapshot is not writable */
1017 
1018 	return generic_permission(&nop_mnt_idmap, inode, mask);
1019 }
1020 
1021 int nilfs_load_inode_block(struct inode *inode, struct buffer_head **pbh)
1022 {
1023 	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
1024 	struct nilfs_inode_info *ii = NILFS_I(inode);
1025 	int err;
1026 
1027 	spin_lock(&nilfs->ns_inode_lock);
1028 	if (ii->i_bh == NULL) {
1029 		spin_unlock(&nilfs->ns_inode_lock);
1030 		err = nilfs_ifile_get_inode_block(ii->i_root->ifile,
1031 						  inode->i_ino, pbh);
1032 		if (unlikely(err))
1033 			return err;
1034 		spin_lock(&nilfs->ns_inode_lock);
1035 		if (ii->i_bh == NULL)
1036 			ii->i_bh = *pbh;
1037 		else {
1038 			brelse(*pbh);
1039 			*pbh = ii->i_bh;
1040 		}
1041 	} else
1042 		*pbh = ii->i_bh;
1043 
1044 	get_bh(*pbh);
1045 	spin_unlock(&nilfs->ns_inode_lock);
1046 	return 0;
1047 }
1048 
1049 int nilfs_inode_dirty(struct inode *inode)
1050 {
1051 	struct nilfs_inode_info *ii = NILFS_I(inode);
1052 	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
1053 	int ret = 0;
1054 
1055 	if (!list_empty(&ii->i_dirty)) {
1056 		spin_lock(&nilfs->ns_inode_lock);
1057 		ret = test_bit(NILFS_I_DIRTY, &ii->i_state) ||
1058 			test_bit(NILFS_I_BUSY, &ii->i_state);
1059 		spin_unlock(&nilfs->ns_inode_lock);
1060 	}
1061 	return ret;
1062 }
1063 
1064 int nilfs_set_file_dirty(struct inode *inode, unsigned int nr_dirty)
1065 {
1066 	struct nilfs_inode_info *ii = NILFS_I(inode);
1067 	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
1068 
1069 	atomic_add(nr_dirty, &nilfs->ns_ndirtyblks);
1070 
1071 	if (test_and_set_bit(NILFS_I_DIRTY, &ii->i_state))
1072 		return 0;
1073 
1074 	spin_lock(&nilfs->ns_inode_lock);
1075 	if (!test_bit(NILFS_I_QUEUED, &ii->i_state) &&
1076 	    !test_bit(NILFS_I_BUSY, &ii->i_state)) {
1077 		/*
1078 		 * Because this routine may race with nilfs_dispose_list(),
1079 		 * we have to check NILFS_I_QUEUED here, too.
1080 		 */
1081 		if (list_empty(&ii->i_dirty) && igrab(inode) == NULL) {
1082 			/*
1083 			 * This will happen when somebody is freeing
1084 			 * this inode.
1085 			 */
1086 			nilfs_warn(inode->i_sb,
1087 				   "cannot set file dirty (ino=%lu): the file is being freed",
1088 				   inode->i_ino);
1089 			spin_unlock(&nilfs->ns_inode_lock);
1090 			return -EINVAL; /*
1091 					 * NILFS_I_DIRTY may remain for
1092 					 * freeing inode.
1093 					 */
1094 		}
1095 		list_move_tail(&ii->i_dirty, &nilfs->ns_dirty_files);
1096 		set_bit(NILFS_I_QUEUED, &ii->i_state);
1097 	}
1098 	spin_unlock(&nilfs->ns_inode_lock);
1099 	return 0;
1100 }
1101 
1102 int __nilfs_mark_inode_dirty(struct inode *inode, int flags)
1103 {
1104 	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
1105 	struct buffer_head *ibh;
1106 	int err;
1107 
1108 	/*
1109 	 * Do not dirty inodes after the log writer has been detached
1110 	 * and its nilfs_root struct has been freed.
1111 	 */
1112 	if (unlikely(nilfs_purging(nilfs)))
1113 		return 0;
1114 
1115 	err = nilfs_load_inode_block(inode, &ibh);
1116 	if (unlikely(err)) {
1117 		nilfs_warn(inode->i_sb,
1118 			   "cannot mark inode dirty (ino=%lu): error %d loading inode block",
1119 			   inode->i_ino, err);
1120 		return err;
1121 	}
1122 	nilfs_update_inode(inode, ibh, flags);
1123 	mark_buffer_dirty(ibh);
1124 	nilfs_mdt_mark_dirty(NILFS_I(inode)->i_root->ifile);
1125 	brelse(ibh);
1126 	return 0;
1127 }
1128 
1129 /**
1130  * nilfs_dirty_inode - reflect changes on given inode to an inode block.
1131  * @inode: inode of the file to be registered.
1132  * @flags: flags to determine the dirty state of the inode
1133  *
1134  * nilfs_dirty_inode() loads a inode block containing the specified
1135  * @inode and copies data from a nilfs_inode to a corresponding inode
1136  * entry in the inode block. This operation is excluded from the segment
1137  * construction. This function can be called both as a single operation
1138  * and as a part of indivisible file operations.
1139  */
1140 void nilfs_dirty_inode(struct inode *inode, int flags)
1141 {
1142 	struct nilfs_transaction_info ti;
1143 	struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
1144 
1145 	if (is_bad_inode(inode)) {
1146 		nilfs_warn(inode->i_sb,
1147 			   "tried to mark bad_inode dirty. ignored.");
1148 		dump_stack();
1149 		return;
1150 	}
1151 	if (mdi) {
1152 		nilfs_mdt_mark_dirty(inode);
1153 		return;
1154 	}
1155 	nilfs_transaction_begin(inode->i_sb, &ti, 0);
1156 	__nilfs_mark_inode_dirty(inode, flags);
1157 	nilfs_transaction_commit(inode->i_sb); /* never fails */
1158 }
1159 
1160 int nilfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
1161 		 __u64 start, __u64 len)
1162 {
1163 	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
1164 	__u64 logical = 0, phys = 0, size = 0;
1165 	__u32 flags = 0;
1166 	loff_t isize;
1167 	sector_t blkoff, end_blkoff;
1168 	sector_t delalloc_blkoff;
1169 	unsigned long delalloc_blklen;
1170 	unsigned int blkbits = inode->i_blkbits;
1171 	int ret, n;
1172 
1173 	ret = fiemap_prep(inode, fieinfo, start, &len, 0);
1174 	if (ret)
1175 		return ret;
1176 
1177 	inode_lock(inode);
1178 
1179 	isize = i_size_read(inode);
1180 
1181 	blkoff = start >> blkbits;
1182 	end_blkoff = (start + len - 1) >> blkbits;
1183 
1184 	delalloc_blklen = nilfs_find_uncommitted_extent(inode, blkoff,
1185 							&delalloc_blkoff);
1186 
1187 	do {
1188 		__u64 blkphy;
1189 		unsigned int maxblocks;
1190 
1191 		if (delalloc_blklen && blkoff == delalloc_blkoff) {
1192 			if (size) {
1193 				/* End of the current extent */
1194 				ret = fiemap_fill_next_extent(
1195 					fieinfo, logical, phys, size, flags);
1196 				if (ret)
1197 					break;
1198 			}
1199 			if (blkoff > end_blkoff)
1200 				break;
1201 
1202 			flags = FIEMAP_EXTENT_MERGED | FIEMAP_EXTENT_DELALLOC;
1203 			logical = blkoff << blkbits;
1204 			phys = 0;
1205 			size = delalloc_blklen << blkbits;
1206 
1207 			blkoff = delalloc_blkoff + delalloc_blklen;
1208 			delalloc_blklen = nilfs_find_uncommitted_extent(
1209 				inode, blkoff, &delalloc_blkoff);
1210 			continue;
1211 		}
1212 
1213 		/*
1214 		 * Limit the number of blocks that we look up so as
1215 		 * not to get into the next delayed allocation extent.
1216 		 */
1217 		maxblocks = INT_MAX;
1218 		if (delalloc_blklen)
1219 			maxblocks = min_t(sector_t, delalloc_blkoff - blkoff,
1220 					  maxblocks);
1221 		blkphy = 0;
1222 
1223 		down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
1224 		n = nilfs_bmap_lookup_contig(
1225 			NILFS_I(inode)->i_bmap, blkoff, &blkphy, maxblocks);
1226 		up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
1227 
1228 		if (n < 0) {
1229 			int past_eof;
1230 
1231 			if (unlikely(n != -ENOENT))
1232 				break; /* error */
1233 
1234 			/* HOLE */
1235 			blkoff++;
1236 			past_eof = ((blkoff << blkbits) >= isize);
1237 
1238 			if (size) {
1239 				/* End of the current extent */
1240 
1241 				if (past_eof)
1242 					flags |= FIEMAP_EXTENT_LAST;
1243 
1244 				ret = fiemap_fill_next_extent(
1245 					fieinfo, logical, phys, size, flags);
1246 				if (ret)
1247 					break;
1248 				size = 0;
1249 			}
1250 			if (blkoff > end_blkoff || past_eof)
1251 				break;
1252 		} else {
1253 			if (size) {
1254 				if (phys && blkphy << blkbits == phys + size) {
1255 					/* The current extent goes on */
1256 					size += n << blkbits;
1257 				} else {
1258 					/* Terminate the current extent */
1259 					ret = fiemap_fill_next_extent(
1260 						fieinfo, logical, phys, size,
1261 						flags);
1262 					if (ret || blkoff > end_blkoff)
1263 						break;
1264 
1265 					/* Start another extent */
1266 					flags = FIEMAP_EXTENT_MERGED;
1267 					logical = blkoff << blkbits;
1268 					phys = blkphy << blkbits;
1269 					size = n << blkbits;
1270 				}
1271 			} else {
1272 				/* Start a new extent */
1273 				flags = FIEMAP_EXTENT_MERGED;
1274 				logical = blkoff << blkbits;
1275 				phys = blkphy << blkbits;
1276 				size = n << blkbits;
1277 			}
1278 			blkoff += n;
1279 		}
1280 		cond_resched();
1281 	} while (true);
1282 
1283 	/* If ret is 1 then we just hit the end of the extent array */
1284 	if (ret == 1)
1285 		ret = 0;
1286 
1287 	inode_unlock(inode);
1288 	return ret;
1289 }
1290