xref: /linux/fs/nilfs2/inode.c (revision 4aa748dd1abf337426b4c941ae1b606ed0e2a5aa)
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 <linux/random.h>
19 #include "nilfs.h"
20 #include "btnode.h"
21 #include "segment.h"
22 #include "page.h"
23 #include "mdt.h"
24 #include "cpfile.h"
25 #include "ifile.h"
26 
27 /**
28  * struct nilfs_iget_args - arguments used during comparison between inodes
29  * @ino: inode number
30  * @cno: checkpoint number
31  * @root: pointer on NILFS root object (mounted checkpoint)
32  * @type: inode type
33  */
34 struct nilfs_iget_args {
35 	u64 ino;
36 	__u64 cno;
37 	struct nilfs_root *root;
38 	unsigned int type;
39 };
40 
41 static int nilfs_iget_test(struct inode *inode, void *opaque);
42 
nilfs_inode_add_blocks(struct inode * inode,int n)43 void nilfs_inode_add_blocks(struct inode *inode, int n)
44 {
45 	struct nilfs_root *root = NILFS_I(inode)->i_root;
46 
47 	inode_add_bytes(inode, i_blocksize(inode) * n);
48 	if (root)
49 		atomic64_add(n, &root->blocks_count);
50 }
51 
nilfs_inode_sub_blocks(struct inode * inode,int n)52 void nilfs_inode_sub_blocks(struct inode *inode, int n)
53 {
54 	struct nilfs_root *root = NILFS_I(inode)->i_root;
55 
56 	inode_sub_bytes(inode, i_blocksize(inode) * n);
57 	if (root)
58 		atomic64_sub(n, &root->blocks_count);
59 }
60 
61 /**
62  * nilfs_get_block() - get a file block on the filesystem (callback function)
63  * @inode: inode struct of the target file
64  * @blkoff: file block number
65  * @bh_result: buffer head to be mapped on
66  * @create: indicate whether allocating the block or not when it has not
67  *      been allocated yet.
68  *
69  * This function does not issue actual read request of the specified data
70  * block. It is done by VFS.
71  */
nilfs_get_block(struct inode * inode,sector_t blkoff,struct buffer_head * bh_result,int create)72 int nilfs_get_block(struct inode *inode, sector_t blkoff,
73 		    struct buffer_head *bh_result, int create)
74 {
75 	struct nilfs_inode_info *ii = NILFS_I(inode);
76 	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
77 	__u64 blknum = 0;
78 	int err = 0, ret;
79 	unsigned int maxblocks = bh_result->b_size >> inode->i_blkbits;
80 
81 	down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
82 	ret = nilfs_bmap_lookup_contig(ii->i_bmap, blkoff, &blknum, maxblocks);
83 	up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
84 	if (ret >= 0) {	/* found */
85 		map_bh(bh_result, inode->i_sb, blknum);
86 		if (ret > 0)
87 			bh_result->b_size = (ret << inode->i_blkbits);
88 		goto out;
89 	}
90 	/* data block was not found */
91 	if (ret == -ENOENT && create) {
92 		struct nilfs_transaction_info ti;
93 
94 		bh_result->b_blocknr = 0;
95 		err = nilfs_transaction_begin(inode->i_sb, &ti, 1);
96 		if (unlikely(err))
97 			goto out;
98 		err = nilfs_bmap_insert(ii->i_bmap, blkoff,
99 					(unsigned long)bh_result);
100 		if (unlikely(err != 0)) {
101 			if (err == -EEXIST) {
102 				/*
103 				 * The get_block() function could be called
104 				 * from multiple callers for an inode.
105 				 * However, the page having this block must
106 				 * be locked in this case.
107 				 */
108 				nilfs_warn(inode->i_sb,
109 					   "%s (ino=%lu): a race condition while inserting a data block at offset=%llu",
110 					   __func__, inode->i_ino,
111 					   (unsigned long long)blkoff);
112 				err = -EAGAIN;
113 			}
114 			nilfs_transaction_abort(inode->i_sb);
115 			goto out;
116 		}
117 		nilfs_mark_inode_dirty_sync(inode);
118 		nilfs_transaction_commit(inode->i_sb); /* never fails */
119 		/* Error handling should be detailed */
120 		set_buffer_new(bh_result);
121 		set_buffer_delay(bh_result);
122 		map_bh(bh_result, inode->i_sb, 0);
123 		/* Disk block number must be changed to proper value */
124 
125 	} else if (ret == -ENOENT) {
126 		/*
127 		 * not found is not error (e.g. hole); must return without
128 		 * the mapped state flag.
129 		 */
130 		;
131 	} else {
132 		err = ret;
133 	}
134 
135  out:
136 	return err;
137 }
138 
139 /**
140  * nilfs_read_folio() - implement read_folio() method of nilfs_aops {}
141  * address_space_operations.
142  * @file: file struct of the file to be read
143  * @folio: the folio to be read
144  */
nilfs_read_folio(struct file * file,struct folio * folio)145 static int nilfs_read_folio(struct file *file, struct folio *folio)
146 {
147 	return mpage_read_folio(folio, nilfs_get_block);
148 }
149 
nilfs_readahead(struct readahead_control * rac)150 static void nilfs_readahead(struct readahead_control *rac)
151 {
152 	mpage_readahead(rac, nilfs_get_block);
153 }
154 
nilfs_writepages(struct address_space * mapping,struct writeback_control * wbc)155 static int nilfs_writepages(struct address_space *mapping,
156 			    struct writeback_control *wbc)
157 {
158 	struct inode *inode = mapping->host;
159 	int err = 0;
160 
161 	if (sb_rdonly(inode->i_sb)) {
162 		nilfs_clear_dirty_pages(mapping);
163 		return -EROFS;
164 	}
165 
166 	if (wbc->sync_mode == WB_SYNC_ALL)
167 		err = nilfs_construct_dsync_segment(inode->i_sb, inode,
168 						    wbc->range_start,
169 						    wbc->range_end);
170 	return err;
171 }
172 
nilfs_dirty_folio(struct address_space * mapping,struct folio * folio)173 static bool nilfs_dirty_folio(struct address_space *mapping,
174 		struct folio *folio)
175 {
176 	struct inode *inode = mapping->host;
177 	struct buffer_head *head;
178 	unsigned int nr_dirty = 0;
179 	bool ret = filemap_dirty_folio(mapping, folio);
180 
181 	/*
182 	 * The page may not be locked, eg if called from try_to_unmap_one()
183 	 */
184 	spin_lock(&mapping->i_private_lock);
185 	head = folio_buffers(folio);
186 	if (head) {
187 		struct buffer_head *bh = head;
188 
189 		do {
190 			/* Do not mark hole blocks dirty */
191 			if (buffer_dirty(bh) || !buffer_mapped(bh))
192 				continue;
193 
194 			set_buffer_dirty(bh);
195 			nr_dirty++;
196 		} while (bh = bh->b_this_page, bh != head);
197 	} else if (ret) {
198 		nr_dirty = 1 << (folio_shift(folio) - inode->i_blkbits);
199 	}
200 	spin_unlock(&mapping->i_private_lock);
201 
202 	if (nr_dirty)
203 		nilfs_set_file_dirty(inode, nr_dirty);
204 	return ret;
205 }
206 
nilfs_write_failed(struct address_space * mapping,loff_t to)207 void nilfs_write_failed(struct address_space *mapping, loff_t to)
208 {
209 	struct inode *inode = mapping->host;
210 
211 	if (to > inode->i_size) {
212 		truncate_pagecache(inode, inode->i_size);
213 		nilfs_truncate(inode);
214 	}
215 }
216 
nilfs_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,struct folio ** foliop,void ** fsdata)217 static int nilfs_write_begin(struct file *file, struct address_space *mapping,
218 			     loff_t pos, unsigned len,
219 			     struct folio **foliop, void **fsdata)
220 
221 {
222 	struct inode *inode = mapping->host;
223 	int err = nilfs_transaction_begin(inode->i_sb, NULL, 1);
224 
225 	if (unlikely(err))
226 		return err;
227 
228 	err = block_write_begin(mapping, pos, len, foliop, nilfs_get_block);
229 	if (unlikely(err)) {
230 		nilfs_write_failed(mapping, pos + len);
231 		nilfs_transaction_abort(inode->i_sb);
232 	}
233 	return err;
234 }
235 
nilfs_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct folio * folio,void * fsdata)236 static int nilfs_write_end(struct file *file, struct address_space *mapping,
237 			   loff_t pos, unsigned len, unsigned copied,
238 			   struct folio *folio, void *fsdata)
239 {
240 	struct inode *inode = mapping->host;
241 	unsigned int start = pos & (PAGE_SIZE - 1);
242 	unsigned int nr_dirty;
243 	int err;
244 
245 	nr_dirty = nilfs_page_count_clean_buffers(folio, start,
246 						  start + copied);
247 	copied = generic_write_end(file, mapping, pos, len, copied, folio,
248 				   fsdata);
249 	nilfs_set_file_dirty(inode, nr_dirty);
250 	err = nilfs_transaction_commit(inode->i_sb);
251 	return err ? : copied;
252 }
253 
254 static ssize_t
nilfs_direct_IO(struct kiocb * iocb,struct iov_iter * iter)255 nilfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
256 {
257 	struct inode *inode = file_inode(iocb->ki_filp);
258 
259 	if (iov_iter_rw(iter) == WRITE)
260 		return 0;
261 
262 	/* Needs synchronization with the cleaner */
263 	return blockdev_direct_IO(iocb, inode, iter, nilfs_get_block);
264 }
265 
266 const struct address_space_operations nilfs_aops = {
267 	.read_folio		= nilfs_read_folio,
268 	.writepages		= nilfs_writepages,
269 	.dirty_folio		= nilfs_dirty_folio,
270 	.readahead		= nilfs_readahead,
271 	.write_begin		= nilfs_write_begin,
272 	.write_end		= nilfs_write_end,
273 	.invalidate_folio	= block_invalidate_folio,
274 	.direct_IO		= nilfs_direct_IO,
275 	.migrate_folio		= buffer_migrate_folio_norefs,
276 	.is_partially_uptodate  = block_is_partially_uptodate,
277 };
278 
279 const struct address_space_operations nilfs_buffer_cache_aops = {
280 	.invalidate_folio	= block_invalidate_folio,
281 };
282 
nilfs_insert_inode_locked(struct inode * inode,struct nilfs_root * root,unsigned long ino)283 static int nilfs_insert_inode_locked(struct inode *inode,
284 				     struct nilfs_root *root,
285 				     unsigned long ino)
286 {
287 	struct nilfs_iget_args args = {
288 		.ino = ino, .root = root, .cno = 0, .type = NILFS_I_TYPE_NORMAL
289 	};
290 
291 	return insert_inode_locked4(inode, ino, nilfs_iget_test, &args);
292 }
293 
nilfs_new_inode(struct inode * dir,umode_t mode)294 struct inode *nilfs_new_inode(struct inode *dir, umode_t mode)
295 {
296 	struct super_block *sb = dir->i_sb;
297 	struct inode *inode;
298 	struct nilfs_inode_info *ii;
299 	struct nilfs_root *root;
300 	struct buffer_head *bh;
301 	int err = -ENOMEM;
302 	ino_t ino;
303 
304 	inode = new_inode(sb);
305 	if (unlikely(!inode))
306 		goto failed;
307 
308 	mapping_set_gfp_mask(inode->i_mapping,
309 			   mapping_gfp_constraint(inode->i_mapping, ~__GFP_FS));
310 
311 	root = NILFS_I(dir)->i_root;
312 	ii = NILFS_I(inode);
313 	ii->i_state = BIT(NILFS_I_NEW);
314 	ii->i_type = NILFS_I_TYPE_NORMAL;
315 	ii->i_root = root;
316 
317 	err = nilfs_ifile_create_inode(root->ifile, &ino, &bh);
318 	if (unlikely(err))
319 		goto failed_ifile_create_inode;
320 	/* reference count of i_bh inherits from nilfs_mdt_read_block() */
321 	ii->i_bh = bh;
322 
323 	atomic64_inc(&root->inodes_count);
324 	inode_init_owner(&nop_mnt_idmap, inode, dir, mode);
325 	inode->i_ino = ino;
326 	simple_inode_init_ts(inode);
327 
328 	if (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)) {
329 		err = nilfs_bmap_read(ii->i_bmap, NULL);
330 		if (err < 0)
331 			goto failed_after_creation;
332 
333 		set_bit(NILFS_I_BMAP, &ii->i_state);
334 		/* No lock is needed; iget() ensures it. */
335 	}
336 
337 	ii->i_flags = nilfs_mask_flags(
338 		mode, NILFS_I(dir)->i_flags & NILFS_FL_INHERITED);
339 
340 	/* ii->i_file_acl = 0; */
341 	/* ii->i_dir_acl = 0; */
342 	ii->i_dir_start_lookup = 0;
343 	nilfs_set_inode_flags(inode);
344 	inode->i_generation = get_random_u32();
345 	if (nilfs_insert_inode_locked(inode, root, ino) < 0) {
346 		err = -EIO;
347 		goto failed_after_creation;
348 	}
349 
350 	err = nilfs_init_acl(inode, dir);
351 	if (unlikely(err))
352 		/*
353 		 * Never occur.  When supporting nilfs_init_acl(),
354 		 * proper cancellation of above jobs should be considered.
355 		 */
356 		goto failed_after_creation;
357 
358 	return inode;
359 
360  failed_after_creation:
361 	clear_nlink(inode);
362 	if (inode->i_state & I_NEW)
363 		unlock_new_inode(inode);
364 	iput(inode);  /*
365 		       * raw_inode will be deleted through
366 		       * nilfs_evict_inode().
367 		       */
368 	goto failed;
369 
370  failed_ifile_create_inode:
371 	make_bad_inode(inode);
372 	iput(inode);
373  failed:
374 	return ERR_PTR(err);
375 }
376 
nilfs_set_inode_flags(struct inode * inode)377 void nilfs_set_inode_flags(struct inode *inode)
378 {
379 	unsigned int flags = NILFS_I(inode)->i_flags;
380 	unsigned int new_fl = 0;
381 
382 	if (flags & FS_SYNC_FL)
383 		new_fl |= S_SYNC;
384 	if (flags & FS_APPEND_FL)
385 		new_fl |= S_APPEND;
386 	if (flags & FS_IMMUTABLE_FL)
387 		new_fl |= S_IMMUTABLE;
388 	if (flags & FS_NOATIME_FL)
389 		new_fl |= S_NOATIME;
390 	if (flags & FS_DIRSYNC_FL)
391 		new_fl |= S_DIRSYNC;
392 	inode_set_flags(inode, new_fl, S_SYNC | S_APPEND | S_IMMUTABLE |
393 			S_NOATIME | S_DIRSYNC);
394 }
395 
nilfs_read_inode_common(struct inode * inode,struct nilfs_inode * raw_inode)396 int nilfs_read_inode_common(struct inode *inode,
397 			    struct nilfs_inode *raw_inode)
398 {
399 	struct nilfs_inode_info *ii = NILFS_I(inode);
400 	int err;
401 
402 	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
403 	i_uid_write(inode, le32_to_cpu(raw_inode->i_uid));
404 	i_gid_write(inode, le32_to_cpu(raw_inode->i_gid));
405 	set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
406 	inode->i_size = le64_to_cpu(raw_inode->i_size);
407 	inode_set_atime(inode, le64_to_cpu(raw_inode->i_mtime),
408 			le32_to_cpu(raw_inode->i_mtime_nsec));
409 	inode_set_ctime(inode, le64_to_cpu(raw_inode->i_ctime),
410 			le32_to_cpu(raw_inode->i_ctime_nsec));
411 	inode_set_mtime(inode, le64_to_cpu(raw_inode->i_mtime),
412 			le32_to_cpu(raw_inode->i_mtime_nsec));
413 	if (nilfs_is_metadata_file_inode(inode) && !S_ISREG(inode->i_mode))
414 		return -EIO; /* this inode is for metadata and corrupted */
415 	if (inode->i_nlink == 0)
416 		return -ESTALE; /* this inode is deleted */
417 
418 	inode->i_blocks = le64_to_cpu(raw_inode->i_blocks);
419 	ii->i_flags = le32_to_cpu(raw_inode->i_flags);
420 #if 0
421 	ii->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
422 	ii->i_dir_acl = S_ISREG(inode->i_mode) ?
423 		0 : le32_to_cpu(raw_inode->i_dir_acl);
424 #endif
425 	ii->i_dir_start_lookup = 0;
426 	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
427 
428 	if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
429 	    S_ISLNK(inode->i_mode)) {
430 		err = nilfs_bmap_read(ii->i_bmap, raw_inode);
431 		if (err < 0)
432 			return err;
433 		set_bit(NILFS_I_BMAP, &ii->i_state);
434 		/* No lock is needed; iget() ensures it. */
435 	}
436 	return 0;
437 }
438 
__nilfs_read_inode(struct super_block * sb,struct nilfs_root * root,unsigned long ino,struct inode * inode)439 static int __nilfs_read_inode(struct super_block *sb,
440 			      struct nilfs_root *root, unsigned long ino,
441 			      struct inode *inode)
442 {
443 	struct the_nilfs *nilfs = sb->s_fs_info;
444 	struct buffer_head *bh;
445 	struct nilfs_inode *raw_inode;
446 	int err;
447 
448 	down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
449 	err = nilfs_ifile_get_inode_block(root->ifile, ino, &bh);
450 	if (unlikely(err))
451 		goto bad_inode;
452 
453 	raw_inode = nilfs_ifile_map_inode(root->ifile, ino, bh);
454 
455 	err = nilfs_read_inode_common(inode, raw_inode);
456 	if (err)
457 		goto failed_unmap;
458 
459 	if (S_ISREG(inode->i_mode)) {
460 		inode->i_op = &nilfs_file_inode_operations;
461 		inode->i_fop = &nilfs_file_operations;
462 		inode->i_mapping->a_ops = &nilfs_aops;
463 	} else if (S_ISDIR(inode->i_mode)) {
464 		inode->i_op = &nilfs_dir_inode_operations;
465 		inode->i_fop = &nilfs_dir_operations;
466 		inode->i_mapping->a_ops = &nilfs_aops;
467 	} else if (S_ISLNK(inode->i_mode)) {
468 		inode->i_op = &nilfs_symlink_inode_operations;
469 		inode_nohighmem(inode);
470 		inode->i_mapping->a_ops = &nilfs_aops;
471 	} else {
472 		inode->i_op = &nilfs_special_inode_operations;
473 		init_special_inode(
474 			inode, inode->i_mode,
475 			huge_decode_dev(le64_to_cpu(raw_inode->i_device_code)));
476 	}
477 	nilfs_ifile_unmap_inode(raw_inode);
478 	brelse(bh);
479 	up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
480 	nilfs_set_inode_flags(inode);
481 	mapping_set_gfp_mask(inode->i_mapping,
482 			   mapping_gfp_constraint(inode->i_mapping, ~__GFP_FS));
483 	return 0;
484 
485  failed_unmap:
486 	nilfs_ifile_unmap_inode(raw_inode);
487 	brelse(bh);
488 
489  bad_inode:
490 	up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
491 	return err;
492 }
493 
nilfs_iget_test(struct inode * inode,void * opaque)494 static int nilfs_iget_test(struct inode *inode, void *opaque)
495 {
496 	struct nilfs_iget_args *args = opaque;
497 	struct nilfs_inode_info *ii;
498 
499 	if (args->ino != inode->i_ino || args->root != NILFS_I(inode)->i_root)
500 		return 0;
501 
502 	ii = NILFS_I(inode);
503 	if (ii->i_type != args->type)
504 		return 0;
505 
506 	return !(args->type & NILFS_I_TYPE_GC) || args->cno == ii->i_cno;
507 }
508 
nilfs_iget_set(struct inode * inode,void * opaque)509 static int nilfs_iget_set(struct inode *inode, void *opaque)
510 {
511 	struct nilfs_iget_args *args = opaque;
512 
513 	inode->i_ino = args->ino;
514 	NILFS_I(inode)->i_cno = args->cno;
515 	NILFS_I(inode)->i_root = args->root;
516 	NILFS_I(inode)->i_type = args->type;
517 	if (args->root && args->ino == NILFS_ROOT_INO)
518 		nilfs_get_root(args->root);
519 	return 0;
520 }
521 
nilfs_ilookup(struct super_block * sb,struct nilfs_root * root,unsigned long ino)522 struct inode *nilfs_ilookup(struct super_block *sb, struct nilfs_root *root,
523 			    unsigned long ino)
524 {
525 	struct nilfs_iget_args args = {
526 		.ino = ino, .root = root, .cno = 0, .type = NILFS_I_TYPE_NORMAL
527 	};
528 
529 	return ilookup5(sb, ino, nilfs_iget_test, &args);
530 }
531 
nilfs_iget_locked(struct super_block * sb,struct nilfs_root * root,unsigned long ino)532 struct inode *nilfs_iget_locked(struct super_block *sb, struct nilfs_root *root,
533 				unsigned long ino)
534 {
535 	struct nilfs_iget_args args = {
536 		.ino = ino, .root = root, .cno = 0, .type = NILFS_I_TYPE_NORMAL
537 	};
538 
539 	return iget5_locked(sb, ino, nilfs_iget_test, nilfs_iget_set, &args);
540 }
541 
nilfs_iget(struct super_block * sb,struct nilfs_root * root,unsigned long ino)542 struct inode *nilfs_iget(struct super_block *sb, struct nilfs_root *root,
543 			 unsigned long ino)
544 {
545 	struct inode *inode;
546 	int err;
547 
548 	inode = nilfs_iget_locked(sb, root, ino);
549 	if (unlikely(!inode))
550 		return ERR_PTR(-ENOMEM);
551 
552 	if (!(inode->i_state & I_NEW)) {
553 		if (!inode->i_nlink) {
554 			iput(inode);
555 			return ERR_PTR(-ESTALE);
556 		}
557 		return inode;
558 	}
559 
560 	err = __nilfs_read_inode(sb, root, ino, inode);
561 	if (unlikely(err)) {
562 		iget_failed(inode);
563 		return ERR_PTR(err);
564 	}
565 	unlock_new_inode(inode);
566 	return inode;
567 }
568 
nilfs_iget_for_gc(struct super_block * sb,unsigned long ino,__u64 cno)569 struct inode *nilfs_iget_for_gc(struct super_block *sb, unsigned long ino,
570 				__u64 cno)
571 {
572 	struct nilfs_iget_args args = {
573 		.ino = ino, .root = NULL, .cno = cno, .type = NILFS_I_TYPE_GC
574 	};
575 	struct inode *inode;
576 	int err;
577 
578 	inode = iget5_locked(sb, ino, nilfs_iget_test, nilfs_iget_set, &args);
579 	if (unlikely(!inode))
580 		return ERR_PTR(-ENOMEM);
581 	if (!(inode->i_state & I_NEW))
582 		return inode;
583 
584 	err = nilfs_init_gcinode(inode);
585 	if (unlikely(err)) {
586 		iget_failed(inode);
587 		return ERR_PTR(err);
588 	}
589 	unlock_new_inode(inode);
590 	return inode;
591 }
592 
593 /**
594  * nilfs_attach_btree_node_cache - attach a B-tree node cache to the inode
595  * @inode: inode object
596  *
597  * nilfs_attach_btree_node_cache() attaches a B-tree node cache to @inode,
598  * or does nothing if the inode already has it.  This function allocates
599  * an additional inode to maintain page cache of B-tree nodes one-on-one.
600  *
601  * Return Value: On success, 0 is returned. On errors, one of the following
602  * negative error code is returned.
603  *
604  * %-ENOMEM - Insufficient memory available.
605  */
nilfs_attach_btree_node_cache(struct inode * inode)606 int nilfs_attach_btree_node_cache(struct inode *inode)
607 {
608 	struct nilfs_inode_info *ii = NILFS_I(inode);
609 	struct inode *btnc_inode;
610 	struct nilfs_iget_args args;
611 
612 	if (ii->i_assoc_inode)
613 		return 0;
614 
615 	args.ino = inode->i_ino;
616 	args.root = ii->i_root;
617 	args.cno = ii->i_cno;
618 	args.type = ii->i_type | NILFS_I_TYPE_BTNC;
619 
620 	btnc_inode = iget5_locked(inode->i_sb, inode->i_ino, nilfs_iget_test,
621 				  nilfs_iget_set, &args);
622 	if (unlikely(!btnc_inode))
623 		return -ENOMEM;
624 	if (btnc_inode->i_state & I_NEW) {
625 		nilfs_init_btnc_inode(btnc_inode);
626 		unlock_new_inode(btnc_inode);
627 	}
628 	NILFS_I(btnc_inode)->i_assoc_inode = inode;
629 	NILFS_I(btnc_inode)->i_bmap = ii->i_bmap;
630 	ii->i_assoc_inode = btnc_inode;
631 
632 	return 0;
633 }
634 
635 /**
636  * nilfs_detach_btree_node_cache - detach the B-tree node cache from the inode
637  * @inode: inode object
638  *
639  * nilfs_detach_btree_node_cache() detaches the B-tree node cache and its
640  * holder inode bound to @inode, or does nothing if @inode doesn't have it.
641  */
nilfs_detach_btree_node_cache(struct inode * inode)642 void nilfs_detach_btree_node_cache(struct inode *inode)
643 {
644 	struct nilfs_inode_info *ii = NILFS_I(inode);
645 	struct inode *btnc_inode = ii->i_assoc_inode;
646 
647 	if (btnc_inode) {
648 		NILFS_I(btnc_inode)->i_assoc_inode = NULL;
649 		ii->i_assoc_inode = NULL;
650 		iput(btnc_inode);
651 	}
652 }
653 
654 /**
655  * nilfs_iget_for_shadow - obtain inode for shadow mapping
656  * @inode: inode object that uses shadow mapping
657  *
658  * nilfs_iget_for_shadow() allocates a pair of inodes that holds page
659  * caches for shadow mapping.  The page cache for data pages is set up
660  * in one inode and the one for b-tree node pages is set up in the
661  * other inode, which is attached to the former inode.
662  *
663  * Return Value: On success, a pointer to the inode for data pages is
664  * returned. On errors, one of the following negative error code is returned
665  * in a pointer type.
666  *
667  * %-ENOMEM - Insufficient memory available.
668  */
nilfs_iget_for_shadow(struct inode * inode)669 struct inode *nilfs_iget_for_shadow(struct inode *inode)
670 {
671 	struct nilfs_iget_args args = {
672 		.ino = inode->i_ino, .root = NULL, .cno = 0,
673 		.type = NILFS_I_TYPE_SHADOW
674 	};
675 	struct inode *s_inode;
676 	int err;
677 
678 	s_inode = iget5_locked(inode->i_sb, inode->i_ino, nilfs_iget_test,
679 			       nilfs_iget_set, &args);
680 	if (unlikely(!s_inode))
681 		return ERR_PTR(-ENOMEM);
682 	if (!(s_inode->i_state & I_NEW))
683 		return inode;
684 
685 	NILFS_I(s_inode)->i_flags = 0;
686 	memset(NILFS_I(s_inode)->i_bmap, 0, sizeof(struct nilfs_bmap));
687 	mapping_set_gfp_mask(s_inode->i_mapping, GFP_NOFS);
688 	s_inode->i_mapping->a_ops = &nilfs_buffer_cache_aops;
689 
690 	err = nilfs_attach_btree_node_cache(s_inode);
691 	if (unlikely(err)) {
692 		iget_failed(s_inode);
693 		return ERR_PTR(err);
694 	}
695 	unlock_new_inode(s_inode);
696 	return s_inode;
697 }
698 
699 /**
700  * nilfs_write_inode_common - export common inode information to on-disk inode
701  * @inode:     inode object
702  * @raw_inode: on-disk inode
703  *
704  * This function writes standard information from the on-memory inode @inode
705  * to @raw_inode on ifile, cpfile or a super root block.  Since inode bmap
706  * data is not exported, nilfs_bmap_write() must be called separately during
707  * log writing.
708  */
nilfs_write_inode_common(struct inode * inode,struct nilfs_inode * raw_inode)709 void nilfs_write_inode_common(struct inode *inode,
710 			      struct nilfs_inode *raw_inode)
711 {
712 	struct nilfs_inode_info *ii = NILFS_I(inode);
713 
714 	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
715 	raw_inode->i_uid = cpu_to_le32(i_uid_read(inode));
716 	raw_inode->i_gid = cpu_to_le32(i_gid_read(inode));
717 	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
718 	raw_inode->i_size = cpu_to_le64(inode->i_size);
719 	raw_inode->i_ctime = cpu_to_le64(inode_get_ctime_sec(inode));
720 	raw_inode->i_mtime = cpu_to_le64(inode_get_mtime_sec(inode));
721 	raw_inode->i_ctime_nsec = cpu_to_le32(inode_get_ctime_nsec(inode));
722 	raw_inode->i_mtime_nsec = cpu_to_le32(inode_get_mtime_nsec(inode));
723 	raw_inode->i_blocks = cpu_to_le64(inode->i_blocks);
724 
725 	raw_inode->i_flags = cpu_to_le32(ii->i_flags);
726 	raw_inode->i_generation = cpu_to_le32(inode->i_generation);
727 
728 	/*
729 	 * When extending inode, nilfs->ns_inode_size should be checked
730 	 * for substitutions of appended fields.
731 	 */
732 }
733 
nilfs_update_inode(struct inode * inode,struct buffer_head * ibh,int flags)734 void nilfs_update_inode(struct inode *inode, struct buffer_head *ibh, int flags)
735 {
736 	ino_t ino = inode->i_ino;
737 	struct nilfs_inode_info *ii = NILFS_I(inode);
738 	struct inode *ifile = ii->i_root->ifile;
739 	struct nilfs_inode *raw_inode;
740 
741 	raw_inode = nilfs_ifile_map_inode(ifile, ino, ibh);
742 
743 	if (test_and_clear_bit(NILFS_I_NEW, &ii->i_state))
744 		memset(raw_inode, 0, NILFS_MDT(ifile)->mi_entry_size);
745 	if (flags & I_DIRTY_DATASYNC)
746 		set_bit(NILFS_I_INODE_SYNC, &ii->i_state);
747 
748 	nilfs_write_inode_common(inode, raw_inode);
749 
750 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
751 		raw_inode->i_device_code =
752 			cpu_to_le64(huge_encode_dev(inode->i_rdev));
753 
754 	nilfs_ifile_unmap_inode(raw_inode);
755 }
756 
757 #define NILFS_MAX_TRUNCATE_BLOCKS	16384  /* 64MB for 4KB block */
758 
nilfs_truncate_bmap(struct nilfs_inode_info * ii,unsigned long from)759 static void nilfs_truncate_bmap(struct nilfs_inode_info *ii,
760 				unsigned long from)
761 {
762 	__u64 b;
763 	int ret;
764 
765 	if (!test_bit(NILFS_I_BMAP, &ii->i_state))
766 		return;
767 repeat:
768 	ret = nilfs_bmap_last_key(ii->i_bmap, &b);
769 	if (ret == -ENOENT)
770 		return;
771 	else if (ret < 0)
772 		goto failed;
773 
774 	if (b < from)
775 		return;
776 
777 	b -= min_t(__u64, NILFS_MAX_TRUNCATE_BLOCKS, b - from);
778 	ret = nilfs_bmap_truncate(ii->i_bmap, b);
779 	nilfs_relax_pressure_in_lock(ii->vfs_inode.i_sb);
780 	if (!ret || (ret == -ENOMEM &&
781 		     nilfs_bmap_truncate(ii->i_bmap, b) == 0))
782 		goto repeat;
783 
784 failed:
785 	nilfs_warn(ii->vfs_inode.i_sb, "error %d truncating bmap (ino=%lu)",
786 		   ret, ii->vfs_inode.i_ino);
787 }
788 
nilfs_truncate(struct inode * inode)789 void nilfs_truncate(struct inode *inode)
790 {
791 	unsigned long blkoff;
792 	unsigned int blocksize;
793 	struct nilfs_transaction_info ti;
794 	struct super_block *sb = inode->i_sb;
795 	struct nilfs_inode_info *ii = NILFS_I(inode);
796 
797 	if (!test_bit(NILFS_I_BMAP, &ii->i_state))
798 		return;
799 	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
800 		return;
801 
802 	blocksize = sb->s_blocksize;
803 	blkoff = (inode->i_size + blocksize - 1) >> sb->s_blocksize_bits;
804 	nilfs_transaction_begin(sb, &ti, 0); /* never fails */
805 
806 	block_truncate_page(inode->i_mapping, inode->i_size, nilfs_get_block);
807 
808 	nilfs_truncate_bmap(ii, blkoff);
809 
810 	inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
811 	if (IS_SYNC(inode))
812 		nilfs_set_transaction_flag(NILFS_TI_SYNC);
813 
814 	nilfs_mark_inode_dirty(inode);
815 	nilfs_set_file_dirty(inode, 0);
816 	nilfs_transaction_commit(sb);
817 	/*
818 	 * May construct a logical segment and may fail in sync mode.
819 	 * But truncate has no return value.
820 	 */
821 }
822 
nilfs_clear_inode(struct inode * inode)823 static void nilfs_clear_inode(struct inode *inode)
824 {
825 	struct nilfs_inode_info *ii = NILFS_I(inode);
826 
827 	/*
828 	 * Free resources allocated in nilfs_read_inode(), here.
829 	 */
830 	BUG_ON(!list_empty(&ii->i_dirty));
831 	brelse(ii->i_bh);
832 	ii->i_bh = NULL;
833 
834 	if (nilfs_is_metadata_file_inode(inode))
835 		nilfs_mdt_clear(inode);
836 
837 	if (test_bit(NILFS_I_BMAP, &ii->i_state))
838 		nilfs_bmap_clear(ii->i_bmap);
839 
840 	if (!(ii->i_type & NILFS_I_TYPE_BTNC))
841 		nilfs_detach_btree_node_cache(inode);
842 
843 	if (ii->i_root && inode->i_ino == NILFS_ROOT_INO)
844 		nilfs_put_root(ii->i_root);
845 }
846 
nilfs_evict_inode(struct inode * inode)847 void nilfs_evict_inode(struct inode *inode)
848 {
849 	struct nilfs_transaction_info ti;
850 	struct super_block *sb = inode->i_sb;
851 	struct nilfs_inode_info *ii = NILFS_I(inode);
852 	struct the_nilfs *nilfs;
853 	int ret;
854 
855 	if (inode->i_nlink || !ii->i_root || unlikely(is_bad_inode(inode))) {
856 		truncate_inode_pages_final(&inode->i_data);
857 		clear_inode(inode);
858 		nilfs_clear_inode(inode);
859 		return;
860 	}
861 	nilfs_transaction_begin(sb, &ti, 0); /* never fails */
862 
863 	truncate_inode_pages_final(&inode->i_data);
864 
865 	nilfs = sb->s_fs_info;
866 	if (unlikely(sb_rdonly(sb) || !nilfs->ns_writer)) {
867 		/*
868 		 * If this inode is about to be disposed after the file system
869 		 * has been degraded to read-only due to file system corruption
870 		 * or after the writer has been detached, do not make any
871 		 * changes that cause writes, just clear it.
872 		 * Do this check after read-locking ns_segctor_sem by
873 		 * nilfs_transaction_begin() in order to avoid a race with
874 		 * the writer detach operation.
875 		 */
876 		clear_inode(inode);
877 		nilfs_clear_inode(inode);
878 		nilfs_transaction_abort(sb);
879 		return;
880 	}
881 
882 	/* TODO: some of the following operations may fail.  */
883 	nilfs_truncate_bmap(ii, 0);
884 	nilfs_mark_inode_dirty(inode);
885 	clear_inode(inode);
886 
887 	ret = nilfs_ifile_delete_inode(ii->i_root->ifile, inode->i_ino);
888 	if (!ret)
889 		atomic64_dec(&ii->i_root->inodes_count);
890 
891 	nilfs_clear_inode(inode);
892 
893 	if (IS_SYNC(inode))
894 		nilfs_set_transaction_flag(NILFS_TI_SYNC);
895 	nilfs_transaction_commit(sb);
896 	/*
897 	 * May construct a logical segment and may fail in sync mode.
898 	 * But delete_inode has no return value.
899 	 */
900 }
901 
nilfs_setattr(struct mnt_idmap * idmap,struct dentry * dentry,struct iattr * iattr)902 int nilfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
903 		  struct iattr *iattr)
904 {
905 	struct nilfs_transaction_info ti;
906 	struct inode *inode = d_inode(dentry);
907 	struct super_block *sb = inode->i_sb;
908 	int err;
909 
910 	err = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
911 	if (err)
912 		return err;
913 
914 	err = nilfs_transaction_begin(sb, &ti, 0);
915 	if (unlikely(err))
916 		return err;
917 
918 	if ((iattr->ia_valid & ATTR_SIZE) &&
919 	    iattr->ia_size != i_size_read(inode)) {
920 		inode_dio_wait(inode);
921 		truncate_setsize(inode, iattr->ia_size);
922 		nilfs_truncate(inode);
923 	}
924 
925 	setattr_copy(&nop_mnt_idmap, inode, iattr);
926 	mark_inode_dirty(inode);
927 
928 	if (iattr->ia_valid & ATTR_MODE) {
929 		err = nilfs_acl_chmod(inode);
930 		if (unlikely(err))
931 			goto out_err;
932 	}
933 
934 	return nilfs_transaction_commit(sb);
935 
936 out_err:
937 	nilfs_transaction_abort(sb);
938 	return err;
939 }
940 
nilfs_permission(struct mnt_idmap * idmap,struct inode * inode,int mask)941 int nilfs_permission(struct mnt_idmap *idmap, struct inode *inode,
942 		     int mask)
943 {
944 	struct nilfs_root *root = NILFS_I(inode)->i_root;
945 
946 	if ((mask & MAY_WRITE) && root &&
947 	    root->cno != NILFS_CPTREE_CURRENT_CNO)
948 		return -EROFS; /* snapshot is not writable */
949 
950 	return generic_permission(&nop_mnt_idmap, inode, mask);
951 }
952 
nilfs_load_inode_block(struct inode * inode,struct buffer_head ** pbh)953 int nilfs_load_inode_block(struct inode *inode, struct buffer_head **pbh)
954 {
955 	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
956 	struct nilfs_inode_info *ii = NILFS_I(inode);
957 	int err;
958 
959 	spin_lock(&nilfs->ns_inode_lock);
960 	if (ii->i_bh == NULL || unlikely(!buffer_uptodate(ii->i_bh))) {
961 		spin_unlock(&nilfs->ns_inode_lock);
962 		err = nilfs_ifile_get_inode_block(ii->i_root->ifile,
963 						  inode->i_ino, pbh);
964 		if (unlikely(err))
965 			return err;
966 		spin_lock(&nilfs->ns_inode_lock);
967 		if (ii->i_bh == NULL)
968 			ii->i_bh = *pbh;
969 		else if (unlikely(!buffer_uptodate(ii->i_bh))) {
970 			__brelse(ii->i_bh);
971 			ii->i_bh = *pbh;
972 		} else {
973 			brelse(*pbh);
974 			*pbh = ii->i_bh;
975 		}
976 	} else
977 		*pbh = ii->i_bh;
978 
979 	get_bh(*pbh);
980 	spin_unlock(&nilfs->ns_inode_lock);
981 	return 0;
982 }
983 
nilfs_inode_dirty(struct inode * inode)984 int nilfs_inode_dirty(struct inode *inode)
985 {
986 	struct nilfs_inode_info *ii = NILFS_I(inode);
987 	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
988 	int ret = 0;
989 
990 	if (!list_empty(&ii->i_dirty)) {
991 		spin_lock(&nilfs->ns_inode_lock);
992 		ret = test_bit(NILFS_I_DIRTY, &ii->i_state) ||
993 			test_bit(NILFS_I_BUSY, &ii->i_state);
994 		spin_unlock(&nilfs->ns_inode_lock);
995 	}
996 	return ret;
997 }
998 
nilfs_set_file_dirty(struct inode * inode,unsigned int nr_dirty)999 int nilfs_set_file_dirty(struct inode *inode, unsigned int nr_dirty)
1000 {
1001 	struct nilfs_inode_info *ii = NILFS_I(inode);
1002 	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
1003 
1004 	atomic_add(nr_dirty, &nilfs->ns_ndirtyblks);
1005 
1006 	if (test_and_set_bit(NILFS_I_DIRTY, &ii->i_state))
1007 		return 0;
1008 
1009 	spin_lock(&nilfs->ns_inode_lock);
1010 	if (!test_bit(NILFS_I_QUEUED, &ii->i_state) &&
1011 	    !test_bit(NILFS_I_BUSY, &ii->i_state)) {
1012 		/*
1013 		 * Because this routine may race with nilfs_dispose_list(),
1014 		 * we have to check NILFS_I_QUEUED here, too.
1015 		 */
1016 		if (list_empty(&ii->i_dirty) && igrab(inode) == NULL) {
1017 			/*
1018 			 * This will happen when somebody is freeing
1019 			 * this inode.
1020 			 */
1021 			nilfs_warn(inode->i_sb,
1022 				   "cannot set file dirty (ino=%lu): the file is being freed",
1023 				   inode->i_ino);
1024 			spin_unlock(&nilfs->ns_inode_lock);
1025 			return -EINVAL; /*
1026 					 * NILFS_I_DIRTY may remain for
1027 					 * freeing inode.
1028 					 */
1029 		}
1030 		list_move_tail(&ii->i_dirty, &nilfs->ns_dirty_files);
1031 		set_bit(NILFS_I_QUEUED, &ii->i_state);
1032 	}
1033 	spin_unlock(&nilfs->ns_inode_lock);
1034 	return 0;
1035 }
1036 
__nilfs_mark_inode_dirty(struct inode * inode,int flags)1037 int __nilfs_mark_inode_dirty(struct inode *inode, int flags)
1038 {
1039 	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
1040 	struct buffer_head *ibh;
1041 	int err;
1042 
1043 	/*
1044 	 * Do not dirty inodes after the log writer has been detached
1045 	 * and its nilfs_root struct has been freed.
1046 	 */
1047 	if (unlikely(nilfs_purging(nilfs)))
1048 		return 0;
1049 
1050 	err = nilfs_load_inode_block(inode, &ibh);
1051 	if (unlikely(err)) {
1052 		nilfs_warn(inode->i_sb,
1053 			   "cannot mark inode dirty (ino=%lu): error %d loading inode block",
1054 			   inode->i_ino, err);
1055 		return err;
1056 	}
1057 	nilfs_update_inode(inode, ibh, flags);
1058 	mark_buffer_dirty(ibh);
1059 	nilfs_mdt_mark_dirty(NILFS_I(inode)->i_root->ifile);
1060 	brelse(ibh);
1061 	return 0;
1062 }
1063 
1064 /**
1065  * nilfs_dirty_inode - reflect changes on given inode to an inode block.
1066  * @inode: inode of the file to be registered.
1067  * @flags: flags to determine the dirty state of the inode
1068  *
1069  * nilfs_dirty_inode() loads a inode block containing the specified
1070  * @inode and copies data from a nilfs_inode to a corresponding inode
1071  * entry in the inode block. This operation is excluded from the segment
1072  * construction. This function can be called both as a single operation
1073  * and as a part of indivisible file operations.
1074  */
nilfs_dirty_inode(struct inode * inode,int flags)1075 void nilfs_dirty_inode(struct inode *inode, int flags)
1076 {
1077 	struct nilfs_transaction_info ti;
1078 	struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
1079 
1080 	if (is_bad_inode(inode)) {
1081 		nilfs_warn(inode->i_sb,
1082 			   "tried to mark bad_inode dirty. ignored.");
1083 		dump_stack();
1084 		return;
1085 	}
1086 	if (mdi) {
1087 		nilfs_mdt_mark_dirty(inode);
1088 		return;
1089 	}
1090 	nilfs_transaction_begin(inode->i_sb, &ti, 0);
1091 	__nilfs_mark_inode_dirty(inode, flags);
1092 	nilfs_transaction_commit(inode->i_sb); /* never fails */
1093 }
1094 
nilfs_fiemap(struct inode * inode,struct fiemap_extent_info * fieinfo,__u64 start,__u64 len)1095 int nilfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
1096 		 __u64 start, __u64 len)
1097 {
1098 	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
1099 	__u64 logical = 0, phys = 0, size = 0;
1100 	__u32 flags = 0;
1101 	loff_t isize;
1102 	sector_t blkoff, end_blkoff;
1103 	sector_t delalloc_blkoff;
1104 	unsigned long delalloc_blklen;
1105 	unsigned int blkbits = inode->i_blkbits;
1106 	int ret, n;
1107 
1108 	ret = fiemap_prep(inode, fieinfo, start, &len, 0);
1109 	if (ret)
1110 		return ret;
1111 
1112 	inode_lock(inode);
1113 
1114 	isize = i_size_read(inode);
1115 
1116 	blkoff = start >> blkbits;
1117 	end_blkoff = (start + len - 1) >> blkbits;
1118 
1119 	delalloc_blklen = nilfs_find_uncommitted_extent(inode, blkoff,
1120 							&delalloc_blkoff);
1121 
1122 	do {
1123 		__u64 blkphy;
1124 		unsigned int maxblocks;
1125 
1126 		if (delalloc_blklen && blkoff == delalloc_blkoff) {
1127 			if (size) {
1128 				/* End of the current extent */
1129 				ret = fiemap_fill_next_extent(
1130 					fieinfo, logical, phys, size, flags);
1131 				if (ret)
1132 					break;
1133 			}
1134 			if (blkoff > end_blkoff)
1135 				break;
1136 
1137 			flags = FIEMAP_EXTENT_MERGED | FIEMAP_EXTENT_DELALLOC;
1138 			logical = blkoff << blkbits;
1139 			phys = 0;
1140 			size = delalloc_blklen << blkbits;
1141 
1142 			blkoff = delalloc_blkoff + delalloc_blklen;
1143 			delalloc_blklen = nilfs_find_uncommitted_extent(
1144 				inode, blkoff, &delalloc_blkoff);
1145 			continue;
1146 		}
1147 
1148 		/*
1149 		 * Limit the number of blocks that we look up so as
1150 		 * not to get into the next delayed allocation extent.
1151 		 */
1152 		maxblocks = INT_MAX;
1153 		if (delalloc_blklen)
1154 			maxblocks = min_t(sector_t, delalloc_blkoff - blkoff,
1155 					  maxblocks);
1156 		blkphy = 0;
1157 
1158 		down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
1159 		n = nilfs_bmap_lookup_contig(
1160 			NILFS_I(inode)->i_bmap, blkoff, &blkphy, maxblocks);
1161 		up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
1162 
1163 		if (n < 0) {
1164 			int past_eof;
1165 
1166 			if (unlikely(n != -ENOENT))
1167 				break; /* error */
1168 
1169 			/* HOLE */
1170 			blkoff++;
1171 			past_eof = ((blkoff << blkbits) >= isize);
1172 
1173 			if (size) {
1174 				/* End of the current extent */
1175 
1176 				if (past_eof)
1177 					flags |= FIEMAP_EXTENT_LAST;
1178 
1179 				ret = fiemap_fill_next_extent(
1180 					fieinfo, logical, phys, size, flags);
1181 				if (ret)
1182 					break;
1183 				size = 0;
1184 			}
1185 			if (blkoff > end_blkoff || past_eof)
1186 				break;
1187 		} else {
1188 			if (size) {
1189 				if (phys && blkphy << blkbits == phys + size) {
1190 					/* The current extent goes on */
1191 					size += n << blkbits;
1192 				} else {
1193 					/* Terminate the current extent */
1194 					ret = fiemap_fill_next_extent(
1195 						fieinfo, logical, phys, size,
1196 						flags);
1197 					if (ret || blkoff > end_blkoff)
1198 						break;
1199 
1200 					/* Start another extent */
1201 					flags = FIEMAP_EXTENT_MERGED;
1202 					logical = blkoff << blkbits;
1203 					phys = blkphy << blkbits;
1204 					size = n << blkbits;
1205 				}
1206 			} else {
1207 				/* Start a new extent */
1208 				flags = FIEMAP_EXTENT_MERGED;
1209 				logical = blkoff << blkbits;
1210 				phys = blkphy << blkbits;
1211 				size = n << blkbits;
1212 			}
1213 			blkoff += n;
1214 		}
1215 		cond_resched();
1216 	} while (true);
1217 
1218 	/* If ret is 1 then we just hit the end of the extent array */
1219 	if (ret == 1)
1220 		ret = 0;
1221 
1222 	inode_unlock(inode);
1223 	return ret;
1224 }
1225