1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/fs/ext4/namei.c
4  *
5  * Copyright (C) 1992, 1993, 1994, 1995
6  * Remy Card (card@masi.ibp.fr)
7  * Laboratoire MASI - Institut Blaise Pascal
8  * Universite Pierre et Marie Curie (Paris VI)
9  *
10  *  from
11  *
12  *  linux/fs/minix/namei.c
13  *
14  *  Copyright (C) 1991, 1992  Linus Torvalds
15  *
16  *  Big-endian to little-endian byte-swapping/bitmaps by
17  *        David S. Miller (davem@caip.rutgers.edu), 1995
18  *  Directory entry file type support and forward compatibility hooks
19  *	for B-tree directories by Theodore Ts'o (tytso@mit.edu), 1998
20  *  Hash Tree Directory indexing (c)
21  *	Daniel Phillips, 2001
22  *  Hash Tree Directory indexing porting
23  *	Christopher Li, 2002
24  *  Hash Tree Directory indexing cleanup
25  *	Theodore Ts'o, 2002
26  */
27 
28 #include <linux/fs.h>
29 #include <linux/pagemap.h>
30 #include <linux/time.h>
31 #include <linux/fcntl.h>
32 #include <linux/stat.h>
33 #include <linux/string.h>
34 #include <linux/quotaops.h>
35 #include <linux/buffer_head.h>
36 #include <linux/bio.h>
37 #include <linux/iversion.h>
38 #include <linux/unicode.h>
39 #include "ext4.h"
40 #include "ext4_jbd2.h"
41 
42 #include "xattr.h"
43 #include "acl.h"
44 
45 #include <trace/events/ext4.h>
46 /*
47  * define how far ahead to read directories while searching them.
48  */
49 #define NAMEI_RA_CHUNKS  2
50 #define NAMEI_RA_BLOCKS  4
51 #define NAMEI_RA_SIZE	     (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS)
52 
ext4_append(handle_t * handle,struct inode * inode,ext4_lblk_t * block)53 static struct buffer_head *ext4_append(handle_t *handle,
54 					struct inode *inode,
55 					ext4_lblk_t *block)
56 {
57 	struct ext4_map_blocks map;
58 	struct buffer_head *bh;
59 	int err;
60 
61 	if (unlikely(EXT4_SB(inode->i_sb)->s_max_dir_size_kb &&
62 		     ((inode->i_size >> 10) >=
63 		      EXT4_SB(inode->i_sb)->s_max_dir_size_kb)))
64 		return ERR_PTR(-ENOSPC);
65 
66 	*block = inode->i_size >> inode->i_sb->s_blocksize_bits;
67 	map.m_lblk = *block;
68 	map.m_len = 1;
69 
70 	/*
71 	 * We're appending new directory block. Make sure the block is not
72 	 * allocated yet, otherwise we will end up corrupting the
73 	 * directory.
74 	 */
75 	err = ext4_map_blocks(NULL, inode, &map, 0);
76 	if (err < 0)
77 		return ERR_PTR(err);
78 	if (err) {
79 		EXT4_ERROR_INODE(inode, "Logical block already allocated");
80 		return ERR_PTR(-EFSCORRUPTED);
81 	}
82 
83 	bh = ext4_bread(handle, inode, *block, EXT4_GET_BLOCKS_CREATE);
84 	if (IS_ERR(bh))
85 		return bh;
86 	inode->i_size += inode->i_sb->s_blocksize;
87 	EXT4_I(inode)->i_disksize = inode->i_size;
88 	err = ext4_mark_inode_dirty(handle, inode);
89 	if (err)
90 		goto out;
91 	BUFFER_TRACE(bh, "get_write_access");
92 	err = ext4_journal_get_write_access(handle, inode->i_sb, bh,
93 					    EXT4_JTR_NONE);
94 	if (err)
95 		goto out;
96 	return bh;
97 
98 out:
99 	brelse(bh);
100 	ext4_std_error(inode->i_sb, err);
101 	return ERR_PTR(err);
102 }
103 
104 static int ext4_dx_csum_verify(struct inode *inode,
105 			       struct ext4_dir_entry *dirent);
106 
107 /*
108  * Hints to ext4_read_dirblock regarding whether we expect a directory
109  * block being read to be an index block, or a block containing
110  * directory entries (and if the latter, whether it was found via a
111  * logical block in an htree index block).  This is used to control
112  * what sort of sanity checkinig ext4_read_dirblock() will do on the
113  * directory block read from the storage device.  EITHER will means
114  * the caller doesn't know what kind of directory block will be read,
115  * so no specific verification will be done.
116  */
117 typedef enum {
118 	EITHER, INDEX, DIRENT, DIRENT_HTREE
119 } dirblock_type_t;
120 
121 #define ext4_read_dirblock(inode, block, type) \
122 	__ext4_read_dirblock((inode), (block), (type), __func__, __LINE__)
123 
__ext4_read_dirblock(struct inode * inode,ext4_lblk_t block,dirblock_type_t type,const char * func,unsigned int line)124 static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
125 						ext4_lblk_t block,
126 						dirblock_type_t type,
127 						const char *func,
128 						unsigned int line)
129 {
130 	struct buffer_head *bh;
131 	struct ext4_dir_entry *dirent;
132 	int is_dx_block = 0;
133 
134 	if (block >= inode->i_size >> inode->i_blkbits) {
135 		ext4_error_inode(inode, func, line, block,
136 		       "Attempting to read directory block (%u) that is past i_size (%llu)",
137 		       block, inode->i_size);
138 		return ERR_PTR(-EFSCORRUPTED);
139 	}
140 
141 	if (ext4_simulate_fail(inode->i_sb, EXT4_SIM_DIRBLOCK_EIO))
142 		bh = ERR_PTR(-EIO);
143 	else
144 		bh = ext4_bread(NULL, inode, block, 0);
145 	if (IS_ERR(bh)) {
146 		__ext4_warning(inode->i_sb, func, line,
147 			       "inode #%lu: lblock %lu: comm %s: "
148 			       "error %ld reading directory block",
149 			       inode->i_ino, (unsigned long)block,
150 			       current->comm, PTR_ERR(bh));
151 
152 		return bh;
153 	}
154 	if (!bh && (type == INDEX || type == DIRENT_HTREE)) {
155 		ext4_error_inode(inode, func, line, block,
156 				 "Directory hole found for htree %s block",
157 				 (type == INDEX) ? "index" : "leaf");
158 		return ERR_PTR(-EFSCORRUPTED);
159 	}
160 	if (!bh)
161 		return NULL;
162 	dirent = (struct ext4_dir_entry *) bh->b_data;
163 	/* Determine whether or not we have an index block */
164 	if (is_dx(inode)) {
165 		if (block == 0)
166 			is_dx_block = 1;
167 		else if (ext4_rec_len_from_disk(dirent->rec_len,
168 						inode->i_sb->s_blocksize) ==
169 			 inode->i_sb->s_blocksize)
170 			is_dx_block = 1;
171 	}
172 	if (!is_dx_block && type == INDEX) {
173 		ext4_error_inode(inode, func, line, block,
174 		       "directory leaf block found instead of index block");
175 		brelse(bh);
176 		return ERR_PTR(-EFSCORRUPTED);
177 	}
178 	if (!ext4_has_metadata_csum(inode->i_sb) ||
179 	    buffer_verified(bh))
180 		return bh;
181 
182 	/*
183 	 * An empty leaf block can get mistaken for a index block; for
184 	 * this reason, we can only check the index checksum when the
185 	 * caller is sure it should be an index block.
186 	 */
187 	if (is_dx_block && type == INDEX) {
188 		if (ext4_dx_csum_verify(inode, dirent) &&
189 		    !ext4_simulate_fail(inode->i_sb, EXT4_SIM_DIRBLOCK_CRC))
190 			set_buffer_verified(bh);
191 		else {
192 			ext4_error_inode_err(inode, func, line, block,
193 					     EFSBADCRC,
194 					     "Directory index failed checksum");
195 			brelse(bh);
196 			return ERR_PTR(-EFSBADCRC);
197 		}
198 	}
199 	if (!is_dx_block) {
200 		if (ext4_dirblock_csum_verify(inode, bh) &&
201 		    !ext4_simulate_fail(inode->i_sb, EXT4_SIM_DIRBLOCK_CRC))
202 			set_buffer_verified(bh);
203 		else {
204 			ext4_error_inode_err(inode, func, line, block,
205 					     EFSBADCRC,
206 					     "Directory block failed checksum");
207 			brelse(bh);
208 			return ERR_PTR(-EFSBADCRC);
209 		}
210 	}
211 	return bh;
212 }
213 
214 #ifdef DX_DEBUG
215 #define dxtrace(command) command
216 #else
217 #define dxtrace(command)
218 #endif
219 
220 struct fake_dirent
221 {
222 	__le32 inode;
223 	__le16 rec_len;
224 	u8 name_len;
225 	u8 file_type;
226 };
227 
228 struct dx_countlimit
229 {
230 	__le16 limit;
231 	__le16 count;
232 };
233 
234 struct dx_entry
235 {
236 	__le32 hash;
237 	__le32 block;
238 };
239 
240 /*
241  * dx_root_info is laid out so that if it should somehow get overlaid by a
242  * dirent the two low bits of the hash version will be zero.  Therefore, the
243  * hash version mod 4 should never be 0.  Sincerely, the paranoia department.
244  */
245 
246 struct dx_root
247 {
248 	struct fake_dirent dot;
249 	char dot_name[4];
250 	struct fake_dirent dotdot;
251 	char dotdot_name[4];
252 	struct dx_root_info
253 	{
254 		__le32 reserved_zero;
255 		u8 hash_version;
256 		u8 info_length; /* 8 */
257 		u8 indirect_levels;
258 		u8 unused_flags;
259 	}
260 	info;
261 	struct dx_entry	entries[];
262 };
263 
264 struct dx_node
265 {
266 	struct fake_dirent fake;
267 	struct dx_entry	entries[];
268 };
269 
270 
271 struct dx_frame
272 {
273 	struct buffer_head *bh;
274 	struct dx_entry *entries;
275 	struct dx_entry *at;
276 };
277 
278 struct dx_map_entry
279 {
280 	u32 hash;
281 	u16 offs;
282 	u16 size;
283 };
284 
285 /*
286  * This goes at the end of each htree block.
287  */
288 struct dx_tail {
289 	u32 dt_reserved;
290 	__le32 dt_checksum;	/* crc32c(uuid+inum+dirblock) */
291 };
292 
293 static inline ext4_lblk_t dx_get_block(struct dx_entry *entry);
294 static void dx_set_block(struct dx_entry *entry, ext4_lblk_t value);
295 static inline unsigned dx_get_hash(struct dx_entry *entry);
296 static void dx_set_hash(struct dx_entry *entry, unsigned value);
297 static unsigned dx_get_count(struct dx_entry *entries);
298 static unsigned dx_get_limit(struct dx_entry *entries);
299 static void dx_set_count(struct dx_entry *entries, unsigned value);
300 static void dx_set_limit(struct dx_entry *entries, unsigned value);
301 static unsigned dx_root_limit(struct inode *dir, unsigned infosize);
302 static unsigned dx_node_limit(struct inode *dir);
303 static struct dx_frame *dx_probe(struct ext4_filename *fname,
304 				 struct inode *dir,
305 				 struct dx_hash_info *hinfo,
306 				 struct dx_frame *frame);
307 static void dx_release(struct dx_frame *frames);
308 static int dx_make_map(struct inode *dir, struct buffer_head *bh,
309 		       struct dx_hash_info *hinfo,
310 		       struct dx_map_entry *map_tail);
311 static void dx_sort_map(struct dx_map_entry *map, unsigned count);
312 static struct ext4_dir_entry_2 *dx_move_dirents(struct inode *dir, char *from,
313 					char *to, struct dx_map_entry *offsets,
314 					int count, unsigned int blocksize);
315 static struct ext4_dir_entry_2 *dx_pack_dirents(struct inode *dir, char *base,
316 						unsigned int blocksize);
317 static void dx_insert_block(struct dx_frame *frame,
318 					u32 hash, ext4_lblk_t block);
319 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
320 				 struct dx_frame *frame,
321 				 struct dx_frame *frames,
322 				 __u32 *start_hash);
323 static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
324 		struct ext4_filename *fname,
325 		struct ext4_dir_entry_2 **res_dir);
326 static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
327 			     struct inode *dir, struct inode *inode);
328 
329 /* checksumming functions */
ext4_initialize_dirent_tail(struct buffer_head * bh,unsigned int blocksize)330 void ext4_initialize_dirent_tail(struct buffer_head *bh,
331 				 unsigned int blocksize)
332 {
333 	struct ext4_dir_entry_tail *t = EXT4_DIRENT_TAIL(bh->b_data, blocksize);
334 
335 	memset(t, 0, sizeof(struct ext4_dir_entry_tail));
336 	t->det_rec_len = ext4_rec_len_to_disk(
337 			sizeof(struct ext4_dir_entry_tail), blocksize);
338 	t->det_reserved_ft = EXT4_FT_DIR_CSUM;
339 }
340 
341 /* Walk through a dirent block to find a checksum "dirent" at the tail */
get_dirent_tail(struct inode * inode,struct buffer_head * bh)342 static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,
343 						   struct buffer_head *bh)
344 {
345 	struct ext4_dir_entry_tail *t;
346 	int blocksize = EXT4_BLOCK_SIZE(inode->i_sb);
347 
348 #ifdef PARANOID
349 	struct ext4_dir_entry *d, *top;
350 
351 	d = (struct ext4_dir_entry *)bh->b_data;
352 	top = (struct ext4_dir_entry *)(bh->b_data +
353 		(blocksize - sizeof(struct ext4_dir_entry_tail)));
354 	while (d < top && ext4_rec_len_from_disk(d->rec_len, blocksize))
355 		d = (struct ext4_dir_entry *)(((void *)d) +
356 		    ext4_rec_len_from_disk(d->rec_len, blocksize));
357 
358 	if (d != top)
359 		return NULL;
360 
361 	t = (struct ext4_dir_entry_tail *)d;
362 #else
363 	t = EXT4_DIRENT_TAIL(bh->b_data, EXT4_BLOCK_SIZE(inode->i_sb));
364 #endif
365 
366 	if (t->det_reserved_zero1 ||
367 	    (ext4_rec_len_from_disk(t->det_rec_len, blocksize) !=
368 	     sizeof(struct ext4_dir_entry_tail)) ||
369 	    t->det_reserved_zero2 ||
370 	    t->det_reserved_ft != EXT4_FT_DIR_CSUM)
371 		return NULL;
372 
373 	return t;
374 }
375 
ext4_dirblock_csum(struct inode * inode,void * dirent,int size)376 static __le32 ext4_dirblock_csum(struct inode *inode, void *dirent, int size)
377 {
378 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
379 	struct ext4_inode_info *ei = EXT4_I(inode);
380 	__u32 csum;
381 
382 	csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
383 	return cpu_to_le32(csum);
384 }
385 
386 #define warn_no_space_for_csum(inode)					\
387 	__warn_no_space_for_csum((inode), __func__, __LINE__)
388 
__warn_no_space_for_csum(struct inode * inode,const char * func,unsigned int line)389 static void __warn_no_space_for_csum(struct inode *inode, const char *func,
390 				     unsigned int line)
391 {
392 	__ext4_warning_inode(inode, func, line,
393 		"No space for directory leaf checksum. Please run e2fsck -D.");
394 }
395 
ext4_dirblock_csum_verify(struct inode * inode,struct buffer_head * bh)396 int ext4_dirblock_csum_verify(struct inode *inode, struct buffer_head *bh)
397 {
398 	struct ext4_dir_entry_tail *t;
399 
400 	if (!ext4_has_metadata_csum(inode->i_sb))
401 		return 1;
402 
403 	t = get_dirent_tail(inode, bh);
404 	if (!t) {
405 		warn_no_space_for_csum(inode);
406 		return 0;
407 	}
408 
409 	if (t->det_checksum != ext4_dirblock_csum(inode, bh->b_data,
410 						  (char *)t - bh->b_data))
411 		return 0;
412 
413 	return 1;
414 }
415 
ext4_dirblock_csum_set(struct inode * inode,struct buffer_head * bh)416 static void ext4_dirblock_csum_set(struct inode *inode,
417 				 struct buffer_head *bh)
418 {
419 	struct ext4_dir_entry_tail *t;
420 
421 	if (!ext4_has_metadata_csum(inode->i_sb))
422 		return;
423 
424 	t = get_dirent_tail(inode, bh);
425 	if (!t) {
426 		warn_no_space_for_csum(inode);
427 		return;
428 	}
429 
430 	t->det_checksum = ext4_dirblock_csum(inode, bh->b_data,
431 					     (char *)t - bh->b_data);
432 }
433 
ext4_handle_dirty_dirblock(handle_t * handle,struct inode * inode,struct buffer_head * bh)434 int ext4_handle_dirty_dirblock(handle_t *handle,
435 			       struct inode *inode,
436 			       struct buffer_head *bh)
437 {
438 	ext4_dirblock_csum_set(inode, bh);
439 	return ext4_handle_dirty_metadata(handle, inode, bh);
440 }
441 
get_dx_countlimit(struct inode * inode,struct ext4_dir_entry * dirent,int * offset)442 static struct dx_countlimit *get_dx_countlimit(struct inode *inode,
443 					       struct ext4_dir_entry *dirent,
444 					       int *offset)
445 {
446 	struct ext4_dir_entry *dp;
447 	struct dx_root_info *root;
448 	int count_offset;
449 	int blocksize = EXT4_BLOCK_SIZE(inode->i_sb);
450 	unsigned int rlen = ext4_rec_len_from_disk(dirent->rec_len, blocksize);
451 
452 	if (rlen == blocksize)
453 		count_offset = 8;
454 	else if (rlen == 12) {
455 		dp = (struct ext4_dir_entry *)(((void *)dirent) + 12);
456 		if (ext4_rec_len_from_disk(dp->rec_len, blocksize) != blocksize - 12)
457 			return NULL;
458 		root = (struct dx_root_info *)(((void *)dp + 12));
459 		if (root->reserved_zero ||
460 		    root->info_length != sizeof(struct dx_root_info))
461 			return NULL;
462 		count_offset = 32;
463 	} else
464 		return NULL;
465 
466 	if (offset)
467 		*offset = count_offset;
468 	return (struct dx_countlimit *)(((void *)dirent) + count_offset);
469 }
470 
ext4_dx_csum(struct inode * inode,struct ext4_dir_entry * dirent,int count_offset,int count,struct dx_tail * t)471 static __le32 ext4_dx_csum(struct inode *inode, struct ext4_dir_entry *dirent,
472 			   int count_offset, int count, struct dx_tail *t)
473 {
474 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
475 	struct ext4_inode_info *ei = EXT4_I(inode);
476 	__u32 csum;
477 	int size;
478 	__u32 dummy_csum = 0;
479 	int offset = offsetof(struct dx_tail, dt_checksum);
480 
481 	size = count_offset + (count * sizeof(struct dx_entry));
482 	csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
483 	csum = ext4_chksum(sbi, csum, (__u8 *)t, offset);
484 	csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
485 
486 	return cpu_to_le32(csum);
487 }
488 
ext4_dx_csum_verify(struct inode * inode,struct ext4_dir_entry * dirent)489 static int ext4_dx_csum_verify(struct inode *inode,
490 			       struct ext4_dir_entry *dirent)
491 {
492 	struct dx_countlimit *c;
493 	struct dx_tail *t;
494 	int count_offset, limit, count;
495 
496 	if (!ext4_has_metadata_csum(inode->i_sb))
497 		return 1;
498 
499 	c = get_dx_countlimit(inode, dirent, &count_offset);
500 	if (!c) {
501 		EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
502 		return 0;
503 	}
504 	limit = le16_to_cpu(c->limit);
505 	count = le16_to_cpu(c->count);
506 	if (count_offset + (limit * sizeof(struct dx_entry)) >
507 	    EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
508 		warn_no_space_for_csum(inode);
509 		return 0;
510 	}
511 	t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
512 
513 	if (t->dt_checksum != ext4_dx_csum(inode, dirent, count_offset,
514 					    count, t))
515 		return 0;
516 	return 1;
517 }
518 
ext4_dx_csum_set(struct inode * inode,struct ext4_dir_entry * dirent)519 static void ext4_dx_csum_set(struct inode *inode, struct ext4_dir_entry *dirent)
520 {
521 	struct dx_countlimit *c;
522 	struct dx_tail *t;
523 	int count_offset, limit, count;
524 
525 	if (!ext4_has_metadata_csum(inode->i_sb))
526 		return;
527 
528 	c = get_dx_countlimit(inode, dirent, &count_offset);
529 	if (!c) {
530 		EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
531 		return;
532 	}
533 	limit = le16_to_cpu(c->limit);
534 	count = le16_to_cpu(c->count);
535 	if (count_offset + (limit * sizeof(struct dx_entry)) >
536 	    EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
537 		warn_no_space_for_csum(inode);
538 		return;
539 	}
540 	t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
541 
542 	t->dt_checksum = ext4_dx_csum(inode, dirent, count_offset, count, t);
543 }
544 
ext4_handle_dirty_dx_node(handle_t * handle,struct inode * inode,struct buffer_head * bh)545 static inline int ext4_handle_dirty_dx_node(handle_t *handle,
546 					    struct inode *inode,
547 					    struct buffer_head *bh)
548 {
549 	ext4_dx_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
550 	return ext4_handle_dirty_metadata(handle, inode, bh);
551 }
552 
553 /*
554  * p is at least 6 bytes before the end of page
555  */
556 static inline struct ext4_dir_entry_2 *
ext4_next_entry(struct ext4_dir_entry_2 * p,unsigned long blocksize)557 ext4_next_entry(struct ext4_dir_entry_2 *p, unsigned long blocksize)
558 {
559 	return (struct ext4_dir_entry_2 *)((char *)p +
560 		ext4_rec_len_from_disk(p->rec_len, blocksize));
561 }
562 
563 /*
564  * Future: use high four bits of block for coalesce-on-delete flags
565  * Mask them off for now.
566  */
567 
dx_get_block(struct dx_entry * entry)568 static inline ext4_lblk_t dx_get_block(struct dx_entry *entry)
569 {
570 	return le32_to_cpu(entry->block) & 0x0fffffff;
571 }
572 
dx_set_block(struct dx_entry * entry,ext4_lblk_t value)573 static inline void dx_set_block(struct dx_entry *entry, ext4_lblk_t value)
574 {
575 	entry->block = cpu_to_le32(value);
576 }
577 
dx_get_hash(struct dx_entry * entry)578 static inline unsigned dx_get_hash(struct dx_entry *entry)
579 {
580 	return le32_to_cpu(entry->hash);
581 }
582 
dx_set_hash(struct dx_entry * entry,unsigned value)583 static inline void dx_set_hash(struct dx_entry *entry, unsigned value)
584 {
585 	entry->hash = cpu_to_le32(value);
586 }
587 
dx_get_count(struct dx_entry * entries)588 static inline unsigned dx_get_count(struct dx_entry *entries)
589 {
590 	return le16_to_cpu(((struct dx_countlimit *) entries)->count);
591 }
592 
dx_get_limit(struct dx_entry * entries)593 static inline unsigned dx_get_limit(struct dx_entry *entries)
594 {
595 	return le16_to_cpu(((struct dx_countlimit *) entries)->limit);
596 }
597 
dx_set_count(struct dx_entry * entries,unsigned value)598 static inline void dx_set_count(struct dx_entry *entries, unsigned value)
599 {
600 	((struct dx_countlimit *) entries)->count = cpu_to_le16(value);
601 }
602 
dx_set_limit(struct dx_entry * entries,unsigned value)603 static inline void dx_set_limit(struct dx_entry *entries, unsigned value)
604 {
605 	((struct dx_countlimit *) entries)->limit = cpu_to_le16(value);
606 }
607 
dx_root_limit(struct inode * dir,unsigned infosize)608 static inline unsigned dx_root_limit(struct inode *dir, unsigned infosize)
609 {
610 	unsigned int entry_space = dir->i_sb->s_blocksize -
611 			ext4_dir_rec_len(1, NULL) -
612 			ext4_dir_rec_len(2, NULL) - infosize;
613 
614 	if (ext4_has_metadata_csum(dir->i_sb))
615 		entry_space -= sizeof(struct dx_tail);
616 	return entry_space / sizeof(struct dx_entry);
617 }
618 
dx_node_limit(struct inode * dir)619 static inline unsigned dx_node_limit(struct inode *dir)
620 {
621 	unsigned int entry_space = dir->i_sb->s_blocksize -
622 			ext4_dir_rec_len(0, dir);
623 
624 	if (ext4_has_metadata_csum(dir->i_sb))
625 		entry_space -= sizeof(struct dx_tail);
626 	return entry_space / sizeof(struct dx_entry);
627 }
628 
629 /*
630  * Debug
631  */
632 #ifdef DX_DEBUG
dx_show_index(char * label,struct dx_entry * entries)633 static void dx_show_index(char * label, struct dx_entry *entries)
634 {
635 	int i, n = dx_get_count (entries);
636 	printk(KERN_DEBUG "%s index", label);
637 	for (i = 0; i < n; i++) {
638 		printk(KERN_CONT " %x->%lu",
639 		       i ? dx_get_hash(entries + i) : 0,
640 		       (unsigned long)dx_get_block(entries + i));
641 	}
642 	printk(KERN_CONT "\n");
643 }
644 
645 struct stats
646 {
647 	unsigned names;
648 	unsigned space;
649 	unsigned bcount;
650 };
651 
dx_show_leaf(struct inode * dir,struct dx_hash_info * hinfo,struct ext4_dir_entry_2 * de,int size,int show_names)652 static struct stats dx_show_leaf(struct inode *dir,
653 				struct dx_hash_info *hinfo,
654 				struct ext4_dir_entry_2 *de,
655 				int size, int show_names)
656 {
657 	unsigned names = 0, space = 0;
658 	char *base = (char *) de;
659 	struct dx_hash_info h = *hinfo;
660 
661 	printk("names: ");
662 	while ((char *) de < base + size)
663 	{
664 		if (de->inode)
665 		{
666 			if (show_names)
667 			{
668 #ifdef CONFIG_FS_ENCRYPTION
669 				int len;
670 				char *name;
671 				struct fscrypt_str fname_crypto_str =
672 					FSTR_INIT(NULL, 0);
673 				int res = 0;
674 
675 				name  = de->name;
676 				len = de->name_len;
677 				if (!IS_ENCRYPTED(dir)) {
678 					/* Directory is not encrypted */
679 					(void) ext4fs_dirhash(dir, de->name,
680 						de->name_len, &h);
681 					printk("%*.s:(U)%x.%u ", len,
682 					       name, h.hash,
683 					       (unsigned) ((char *) de
684 							   - base));
685 				} else {
686 					struct fscrypt_str de_name =
687 						FSTR_INIT(name, len);
688 
689 					/* Directory is encrypted */
690 					res = fscrypt_fname_alloc_buffer(
691 						len, &fname_crypto_str);
692 					if (res)
693 						printk(KERN_WARNING "Error "
694 							"allocating crypto "
695 							"buffer--skipping "
696 							"crypto\n");
697 					res = fscrypt_fname_disk_to_usr(dir,
698 						0, 0, &de_name,
699 						&fname_crypto_str);
700 					if (res) {
701 						printk(KERN_WARNING "Error "
702 							"converting filename "
703 							"from disk to usr"
704 							"\n");
705 						name = "??";
706 						len = 2;
707 					} else {
708 						name = fname_crypto_str.name;
709 						len = fname_crypto_str.len;
710 					}
711 					if (IS_CASEFOLDED(dir))
712 						h.hash = EXT4_DIRENT_HASH(de);
713 					else
714 						(void) ext4fs_dirhash(dir,
715 							de->name,
716 							de->name_len, &h);
717 					printk("%*.s:(E)%x.%u ", len, name,
718 					       h.hash, (unsigned) ((char *) de
719 								   - base));
720 					fscrypt_fname_free_buffer(
721 							&fname_crypto_str);
722 				}
723 #else
724 				int len = de->name_len;
725 				char *name = de->name;
726 				(void) ext4fs_dirhash(dir, de->name,
727 						      de->name_len, &h);
728 				printk("%*.s:%x.%u ", len, name, h.hash,
729 				       (unsigned) ((char *) de - base));
730 #endif
731 			}
732 			space += ext4_dir_rec_len(de->name_len, dir);
733 			names++;
734 		}
735 		de = ext4_next_entry(de, size);
736 	}
737 	printk(KERN_CONT "(%i)\n", names);
738 	return (struct stats) { names, space, 1 };
739 }
740 
dx_show_entries(struct dx_hash_info * hinfo,struct inode * dir,struct dx_entry * entries,int levels)741 struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir,
742 			     struct dx_entry *entries, int levels)
743 {
744 	unsigned blocksize = dir->i_sb->s_blocksize;
745 	unsigned count = dx_get_count(entries), names = 0, space = 0, i;
746 	unsigned bcount = 0;
747 	struct buffer_head *bh;
748 	printk("%i indexed blocks...\n", count);
749 	for (i = 0; i < count; i++, entries++)
750 	{
751 		ext4_lblk_t block = dx_get_block(entries);
752 		ext4_lblk_t hash  = i ? dx_get_hash(entries): 0;
753 		u32 range = i < count - 1? (dx_get_hash(entries + 1) - hash): ~hash;
754 		struct stats stats;
755 		printk("%s%3u:%03u hash %8x/%8x ",levels?"":"   ", i, block, hash, range);
756 		bh = ext4_bread(NULL,dir, block, 0);
757 		if (!bh || IS_ERR(bh))
758 			continue;
759 		stats = levels?
760 		   dx_show_entries(hinfo, dir, ((struct dx_node *) bh->b_data)->entries, levels - 1):
761 		   dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *)
762 			bh->b_data, blocksize, 0);
763 		names += stats.names;
764 		space += stats.space;
765 		bcount += stats.bcount;
766 		brelse(bh);
767 	}
768 	if (bcount)
769 		printk(KERN_DEBUG "%snames %u, fullness %u (%u%%)\n",
770 		       levels ? "" : "   ", names, space/bcount,
771 		       (space/bcount)*100/blocksize);
772 	return (struct stats) { names, space, bcount};
773 }
774 
775 /*
776  * Linear search cross check
777  */
htree_rep_invariant_check(struct dx_entry * at,struct dx_entry * target,u32 hash,unsigned int n)778 static inline void htree_rep_invariant_check(struct dx_entry *at,
779 					     struct dx_entry *target,
780 					     u32 hash, unsigned int n)
781 {
782 	while (n--) {
783 		dxtrace(printk(KERN_CONT ","));
784 		if (dx_get_hash(++at) > hash) {
785 			at--;
786 			break;
787 		}
788 	}
789 	ASSERT(at == target - 1);
790 }
791 #else /* DX_DEBUG */
htree_rep_invariant_check(struct dx_entry * at,struct dx_entry * target,u32 hash,unsigned int n)792 static inline void htree_rep_invariant_check(struct dx_entry *at,
793 					     struct dx_entry *target,
794 					     u32 hash, unsigned int n)
795 {
796 }
797 #endif /* DX_DEBUG */
798 
799 /*
800  * Probe for a directory leaf block to search.
801  *
802  * dx_probe can return ERR_BAD_DX_DIR, which means there was a format
803  * error in the directory index, and the caller should fall back to
804  * searching the directory normally.  The callers of dx_probe **MUST**
805  * check for this error code, and make sure it never gets reflected
806  * back to userspace.
807  */
808 static struct dx_frame *
dx_probe(struct ext4_filename * fname,struct inode * dir,struct dx_hash_info * hinfo,struct dx_frame * frame_in)809 dx_probe(struct ext4_filename *fname, struct inode *dir,
810 	 struct dx_hash_info *hinfo, struct dx_frame *frame_in)
811 {
812 	unsigned count, indirect, level, i;
813 	struct dx_entry *at, *entries, *p, *q, *m;
814 	struct dx_root *root;
815 	struct dx_frame *frame = frame_in;
816 	struct dx_frame *ret_err = ERR_PTR(ERR_BAD_DX_DIR);
817 	u32 hash;
818 	ext4_lblk_t block;
819 	ext4_lblk_t blocks[EXT4_HTREE_LEVEL];
820 
821 	memset(frame_in, 0, EXT4_HTREE_LEVEL * sizeof(frame_in[0]));
822 	frame->bh = ext4_read_dirblock(dir, 0, INDEX);
823 	if (IS_ERR(frame->bh))
824 		return (struct dx_frame *) frame->bh;
825 
826 	root = (struct dx_root *) frame->bh->b_data;
827 	if (root->info.hash_version != DX_HASH_TEA &&
828 	    root->info.hash_version != DX_HASH_HALF_MD4 &&
829 	    root->info.hash_version != DX_HASH_LEGACY &&
830 	    root->info.hash_version != DX_HASH_SIPHASH) {
831 		ext4_warning_inode(dir, "Unrecognised inode hash code %u",
832 				   root->info.hash_version);
833 		goto fail;
834 	}
835 	if (ext4_hash_in_dirent(dir)) {
836 		if (root->info.hash_version != DX_HASH_SIPHASH) {
837 			ext4_warning_inode(dir,
838 				"Hash in dirent, but hash is not SIPHASH");
839 			goto fail;
840 		}
841 	} else {
842 		if (root->info.hash_version == DX_HASH_SIPHASH) {
843 			ext4_warning_inode(dir,
844 				"Hash code is SIPHASH, but hash not in dirent");
845 			goto fail;
846 		}
847 	}
848 	if (fname)
849 		hinfo = &fname->hinfo;
850 	hinfo->hash_version = root->info.hash_version;
851 	if (hinfo->hash_version <= DX_HASH_TEA)
852 		hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
853 	hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
854 	/* hash is already computed for encrypted casefolded directory */
855 	if (fname && fname_name(fname) &&
856 	    !(IS_ENCRYPTED(dir) && IS_CASEFOLDED(dir))) {
857 		int ret = ext4fs_dirhash(dir, fname_name(fname),
858 					 fname_len(fname), hinfo);
859 		if (ret < 0) {
860 			ret_err = ERR_PTR(ret);
861 			goto fail;
862 		}
863 	}
864 	hash = hinfo->hash;
865 
866 	if (root->info.unused_flags & 1) {
867 		ext4_warning_inode(dir, "Unimplemented hash flags: %#06x",
868 				   root->info.unused_flags);
869 		goto fail;
870 	}
871 
872 	indirect = root->info.indirect_levels;
873 	if (indirect >= ext4_dir_htree_level(dir->i_sb)) {
874 		ext4_warning(dir->i_sb,
875 			     "Directory (ino: %lu) htree depth %#06x exceed"
876 			     "supported value", dir->i_ino,
877 			     ext4_dir_htree_level(dir->i_sb));
878 		if (ext4_dir_htree_level(dir->i_sb) < EXT4_HTREE_LEVEL) {
879 			ext4_warning(dir->i_sb, "Enable large directory "
880 						"feature to access it");
881 		}
882 		goto fail;
883 	}
884 
885 	entries = (struct dx_entry *)(((char *)&root->info) +
886 				      root->info.info_length);
887 
888 	if (dx_get_limit(entries) != dx_root_limit(dir,
889 						   root->info.info_length)) {
890 		ext4_warning_inode(dir, "dx entry: limit %u != root limit %u",
891 				   dx_get_limit(entries),
892 				   dx_root_limit(dir, root->info.info_length));
893 		goto fail;
894 	}
895 
896 	dxtrace(printk("Look up %x", hash));
897 	level = 0;
898 	blocks[0] = 0;
899 	while (1) {
900 		count = dx_get_count(entries);
901 		if (!count || count > dx_get_limit(entries)) {
902 			ext4_warning_inode(dir,
903 					   "dx entry: count %u beyond limit %u",
904 					   count, dx_get_limit(entries));
905 			goto fail;
906 		}
907 
908 		p = entries + 1;
909 		q = entries + count - 1;
910 		while (p <= q) {
911 			m = p + (q - p) / 2;
912 			dxtrace(printk(KERN_CONT "."));
913 			if (dx_get_hash(m) > hash)
914 				q = m - 1;
915 			else
916 				p = m + 1;
917 		}
918 
919 		htree_rep_invariant_check(entries, p, hash, count - 1);
920 
921 		at = p - 1;
922 		dxtrace(printk(KERN_CONT " %x->%u\n",
923 			       at == entries ? 0 : dx_get_hash(at),
924 			       dx_get_block(at)));
925 		frame->entries = entries;
926 		frame->at = at;
927 
928 		block = dx_get_block(at);
929 		for (i = 0; i <= level; i++) {
930 			if (blocks[i] == block) {
931 				ext4_warning_inode(dir,
932 					"dx entry: tree cycle block %u points back to block %u",
933 					blocks[level], block);
934 				goto fail;
935 			}
936 		}
937 		if (++level > indirect)
938 			return frame;
939 		blocks[level] = block;
940 		frame++;
941 		frame->bh = ext4_read_dirblock(dir, block, INDEX);
942 		if (IS_ERR(frame->bh)) {
943 			ret_err = (struct dx_frame *) frame->bh;
944 			frame->bh = NULL;
945 			goto fail;
946 		}
947 
948 		entries = ((struct dx_node *) frame->bh->b_data)->entries;
949 
950 		if (dx_get_limit(entries) != dx_node_limit(dir)) {
951 			ext4_warning_inode(dir,
952 				"dx entry: limit %u != node limit %u",
953 				dx_get_limit(entries), dx_node_limit(dir));
954 			goto fail;
955 		}
956 	}
957 fail:
958 	while (frame >= frame_in) {
959 		brelse(frame->bh);
960 		frame--;
961 	}
962 
963 	if (ret_err == ERR_PTR(ERR_BAD_DX_DIR))
964 		ext4_warning_inode(dir,
965 			"Corrupt directory, running e2fsck is recommended");
966 	return ret_err;
967 }
968 
dx_release(struct dx_frame * frames)969 static void dx_release(struct dx_frame *frames)
970 {
971 	struct dx_root_info *info;
972 	int i;
973 	unsigned int indirect_levels;
974 
975 	if (frames[0].bh == NULL)
976 		return;
977 
978 	info = &((struct dx_root *)frames[0].bh->b_data)->info;
979 	/* save local copy, "info" may be freed after brelse() */
980 	indirect_levels = info->indirect_levels;
981 	for (i = 0; i <= indirect_levels; i++) {
982 		if (frames[i].bh == NULL)
983 			break;
984 		brelse(frames[i].bh);
985 		frames[i].bh = NULL;
986 	}
987 }
988 
989 /*
990  * This function increments the frame pointer to search the next leaf
991  * block, and reads in the necessary intervening nodes if the search
992  * should be necessary.  Whether or not the search is necessary is
993  * controlled by the hash parameter.  If the hash value is even, then
994  * the search is only continued if the next block starts with that
995  * hash value.  This is used if we are searching for a specific file.
996  *
997  * If the hash value is HASH_NB_ALWAYS, then always go to the next block.
998  *
999  * This function returns 1 if the caller should continue to search,
1000  * or 0 if it should not.  If there is an error reading one of the
1001  * index blocks, it will a negative error code.
1002  *
1003  * If start_hash is non-null, it will be filled in with the starting
1004  * hash of the next page.
1005  */
ext4_htree_next_block(struct inode * dir,__u32 hash,struct dx_frame * frame,struct dx_frame * frames,__u32 * start_hash)1006 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
1007 				 struct dx_frame *frame,
1008 				 struct dx_frame *frames,
1009 				 __u32 *start_hash)
1010 {
1011 	struct dx_frame *p;
1012 	struct buffer_head *bh;
1013 	int num_frames = 0;
1014 	__u32 bhash;
1015 
1016 	p = frame;
1017 	/*
1018 	 * Find the next leaf page by incrementing the frame pointer.
1019 	 * If we run out of entries in the interior node, loop around and
1020 	 * increment pointer in the parent node.  When we break out of
1021 	 * this loop, num_frames indicates the number of interior
1022 	 * nodes need to be read.
1023 	 */
1024 	while (1) {
1025 		if (++(p->at) < p->entries + dx_get_count(p->entries))
1026 			break;
1027 		if (p == frames)
1028 			return 0;
1029 		num_frames++;
1030 		p--;
1031 	}
1032 
1033 	/*
1034 	 * If the hash is 1, then continue only if the next page has a
1035 	 * continuation hash of any value.  This is used for readdir
1036 	 * handling.  Otherwise, check to see if the hash matches the
1037 	 * desired continuation hash.  If it doesn't, return since
1038 	 * there's no point to read in the successive index pages.
1039 	 */
1040 	bhash = dx_get_hash(p->at);
1041 	if (start_hash)
1042 		*start_hash = bhash;
1043 	if ((hash & 1) == 0) {
1044 		if ((bhash & ~1) != hash)
1045 			return 0;
1046 	}
1047 	/*
1048 	 * If the hash is HASH_NB_ALWAYS, we always go to the next
1049 	 * block so no check is necessary
1050 	 */
1051 	while (num_frames--) {
1052 		bh = ext4_read_dirblock(dir, dx_get_block(p->at), INDEX);
1053 		if (IS_ERR(bh))
1054 			return PTR_ERR(bh);
1055 		p++;
1056 		brelse(p->bh);
1057 		p->bh = bh;
1058 		p->at = p->entries = ((struct dx_node *) bh->b_data)->entries;
1059 	}
1060 	return 1;
1061 }
1062 
1063 
1064 /*
1065  * This function fills a red-black tree with information from a
1066  * directory block.  It returns the number directory entries loaded
1067  * into the tree.  If there is an error it is returned in err.
1068  */
htree_dirblock_to_tree(struct file * dir_file,struct inode * dir,ext4_lblk_t block,struct dx_hash_info * hinfo,__u32 start_hash,__u32 start_minor_hash)1069 static int htree_dirblock_to_tree(struct file *dir_file,
1070 				  struct inode *dir, ext4_lblk_t block,
1071 				  struct dx_hash_info *hinfo,
1072 				  __u32 start_hash, __u32 start_minor_hash)
1073 {
1074 	struct buffer_head *bh;
1075 	struct ext4_dir_entry_2 *de, *top;
1076 	int err = 0, count = 0;
1077 	struct fscrypt_str fname_crypto_str = FSTR_INIT(NULL, 0), tmp_str;
1078 	int csum = ext4_has_metadata_csum(dir->i_sb);
1079 
1080 	dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
1081 							(unsigned long)block));
1082 	bh = ext4_read_dirblock(dir, block, DIRENT_HTREE);
1083 	if (IS_ERR(bh))
1084 		return PTR_ERR(bh);
1085 
1086 	de = (struct ext4_dir_entry_2 *) bh->b_data;
1087 	/* csum entries are not larger in the casefolded encrypted case */
1088 	top = (struct ext4_dir_entry_2 *) ((char *) de +
1089 					   dir->i_sb->s_blocksize -
1090 					   ext4_dir_rec_len(0,
1091 							   csum ? NULL : dir));
1092 	/* Check if the directory is encrypted */
1093 	if (IS_ENCRYPTED(dir)) {
1094 		err = fscrypt_prepare_readdir(dir);
1095 		if (err < 0) {
1096 			brelse(bh);
1097 			return err;
1098 		}
1099 		err = fscrypt_fname_alloc_buffer(EXT4_NAME_LEN,
1100 						 &fname_crypto_str);
1101 		if (err < 0) {
1102 			brelse(bh);
1103 			return err;
1104 		}
1105 	}
1106 
1107 	for (; de < top; de = ext4_next_entry(de, dir->i_sb->s_blocksize)) {
1108 		if (ext4_check_dir_entry(dir, NULL, de, bh,
1109 				bh->b_data, bh->b_size,
1110 				(block<<EXT4_BLOCK_SIZE_BITS(dir->i_sb))
1111 					 + ((char *)de - bh->b_data))) {
1112 			/* silently ignore the rest of the block */
1113 			break;
1114 		}
1115 		if (ext4_hash_in_dirent(dir)) {
1116 			if (de->name_len && de->inode) {
1117 				hinfo->hash = EXT4_DIRENT_HASH(de);
1118 				hinfo->minor_hash = EXT4_DIRENT_MINOR_HASH(de);
1119 			} else {
1120 				hinfo->hash = 0;
1121 				hinfo->minor_hash = 0;
1122 			}
1123 		} else {
1124 			err = ext4fs_dirhash(dir, de->name,
1125 					     de->name_len, hinfo);
1126 			if (err < 0) {
1127 				count = err;
1128 				goto errout;
1129 			}
1130 		}
1131 		if ((hinfo->hash < start_hash) ||
1132 		    ((hinfo->hash == start_hash) &&
1133 		     (hinfo->minor_hash < start_minor_hash)))
1134 			continue;
1135 		if (de->inode == 0)
1136 			continue;
1137 		if (!IS_ENCRYPTED(dir)) {
1138 			tmp_str.name = de->name;
1139 			tmp_str.len = de->name_len;
1140 			err = ext4_htree_store_dirent(dir_file,
1141 				   hinfo->hash, hinfo->minor_hash, de,
1142 				   &tmp_str);
1143 		} else {
1144 			int save_len = fname_crypto_str.len;
1145 			struct fscrypt_str de_name = FSTR_INIT(de->name,
1146 								de->name_len);
1147 
1148 			/* Directory is encrypted */
1149 			err = fscrypt_fname_disk_to_usr(dir, hinfo->hash,
1150 					hinfo->minor_hash, &de_name,
1151 					&fname_crypto_str);
1152 			if (err) {
1153 				count = err;
1154 				goto errout;
1155 			}
1156 			err = ext4_htree_store_dirent(dir_file,
1157 				   hinfo->hash, hinfo->minor_hash, de,
1158 					&fname_crypto_str);
1159 			fname_crypto_str.len = save_len;
1160 		}
1161 		if (err != 0) {
1162 			count = err;
1163 			goto errout;
1164 		}
1165 		count++;
1166 	}
1167 errout:
1168 	brelse(bh);
1169 	fscrypt_fname_free_buffer(&fname_crypto_str);
1170 	return count;
1171 }
1172 
1173 
1174 /*
1175  * This function fills a red-black tree with information from a
1176  * directory.  We start scanning the directory in hash order, starting
1177  * at start_hash and start_minor_hash.
1178  *
1179  * This function returns the number of entries inserted into the tree,
1180  * or a negative error code.
1181  */
ext4_htree_fill_tree(struct file * dir_file,__u32 start_hash,__u32 start_minor_hash,__u32 * next_hash)1182 int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
1183 			 __u32 start_minor_hash, __u32 *next_hash)
1184 {
1185 	struct dx_hash_info hinfo;
1186 	struct ext4_dir_entry_2 *de;
1187 	struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
1188 	struct inode *dir;
1189 	ext4_lblk_t block;
1190 	int count = 0;
1191 	int ret, err;
1192 	__u32 hashval;
1193 	struct fscrypt_str tmp_str;
1194 
1195 	dxtrace(printk(KERN_DEBUG "In htree_fill_tree, start hash: %x:%x\n",
1196 		       start_hash, start_minor_hash));
1197 	dir = file_inode(dir_file);
1198 	if (!(ext4_test_inode_flag(dir, EXT4_INODE_INDEX))) {
1199 		if (ext4_hash_in_dirent(dir))
1200 			hinfo.hash_version = DX_HASH_SIPHASH;
1201 		else
1202 			hinfo.hash_version =
1203 					EXT4_SB(dir->i_sb)->s_def_hash_version;
1204 		if (hinfo.hash_version <= DX_HASH_TEA)
1205 			hinfo.hash_version +=
1206 				EXT4_SB(dir->i_sb)->s_hash_unsigned;
1207 		hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
1208 		if (ext4_has_inline_data(dir)) {
1209 			int has_inline_data = 1;
1210 			count = ext4_inlinedir_to_tree(dir_file, dir, 0,
1211 						       &hinfo, start_hash,
1212 						       start_minor_hash,
1213 						       &has_inline_data);
1214 			if (has_inline_data) {
1215 				*next_hash = ~0;
1216 				return count;
1217 			}
1218 		}
1219 		count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
1220 					       start_hash, start_minor_hash);
1221 		*next_hash = ~0;
1222 		return count;
1223 	}
1224 	hinfo.hash = start_hash;
1225 	hinfo.minor_hash = 0;
1226 	frame = dx_probe(NULL, dir, &hinfo, frames);
1227 	if (IS_ERR(frame))
1228 		return PTR_ERR(frame);
1229 
1230 	/* Add '.' and '..' from the htree header */
1231 	if (!start_hash && !start_minor_hash) {
1232 		de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
1233 		tmp_str.name = de->name;
1234 		tmp_str.len = de->name_len;
1235 		err = ext4_htree_store_dirent(dir_file, 0, 0,
1236 					      de, &tmp_str);
1237 		if (err != 0)
1238 			goto errout;
1239 		count++;
1240 	}
1241 	if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) {
1242 		de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
1243 		de = ext4_next_entry(de, dir->i_sb->s_blocksize);
1244 		tmp_str.name = de->name;
1245 		tmp_str.len = de->name_len;
1246 		err = ext4_htree_store_dirent(dir_file, 2, 0,
1247 					      de, &tmp_str);
1248 		if (err != 0)
1249 			goto errout;
1250 		count++;
1251 	}
1252 
1253 	while (1) {
1254 		if (fatal_signal_pending(current)) {
1255 			err = -ERESTARTSYS;
1256 			goto errout;
1257 		}
1258 		cond_resched();
1259 		block = dx_get_block(frame->at);
1260 		ret = htree_dirblock_to_tree(dir_file, dir, block, &hinfo,
1261 					     start_hash, start_minor_hash);
1262 		if (ret < 0) {
1263 			err = ret;
1264 			goto errout;
1265 		}
1266 		count += ret;
1267 		hashval = ~0;
1268 		ret = ext4_htree_next_block(dir, HASH_NB_ALWAYS,
1269 					    frame, frames, &hashval);
1270 		*next_hash = hashval;
1271 		if (ret < 0) {
1272 			err = ret;
1273 			goto errout;
1274 		}
1275 		/*
1276 		 * Stop if:  (a) there are no more entries, or
1277 		 * (b) we have inserted at least one entry and the
1278 		 * next hash value is not a continuation
1279 		 */
1280 		if ((ret == 0) ||
1281 		    (count && ((hashval & 1) == 0)))
1282 			break;
1283 	}
1284 	dx_release(frames);
1285 	dxtrace(printk(KERN_DEBUG "Fill tree: returned %d entries, "
1286 		       "next hash: %x\n", count, *next_hash));
1287 	return count;
1288 errout:
1289 	dx_release(frames);
1290 	return (err);
1291 }
1292 
search_dirblock(struct buffer_head * bh,struct inode * dir,struct ext4_filename * fname,unsigned int offset,struct ext4_dir_entry_2 ** res_dir)1293 static inline int search_dirblock(struct buffer_head *bh,
1294 				  struct inode *dir,
1295 				  struct ext4_filename *fname,
1296 				  unsigned int offset,
1297 				  struct ext4_dir_entry_2 **res_dir)
1298 {
1299 	return ext4_search_dir(bh, bh->b_data, dir->i_sb->s_blocksize, dir,
1300 			       fname, offset, res_dir);
1301 }
1302 
1303 /*
1304  * Directory block splitting, compacting
1305  */
1306 
1307 /*
1308  * Create map of hash values, offsets, and sizes, stored at end of block.
1309  * Returns number of entries mapped.
1310  */
dx_make_map(struct inode * dir,struct buffer_head * bh,struct dx_hash_info * hinfo,struct dx_map_entry * map_tail)1311 static int dx_make_map(struct inode *dir, struct buffer_head *bh,
1312 		       struct dx_hash_info *hinfo,
1313 		       struct dx_map_entry *map_tail)
1314 {
1315 	int count = 0;
1316 	struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)bh->b_data;
1317 	unsigned int buflen = bh->b_size;
1318 	char *base = bh->b_data;
1319 	struct dx_hash_info h = *hinfo;
1320 	int blocksize = EXT4_BLOCK_SIZE(dir->i_sb);
1321 
1322 	if (ext4_has_metadata_csum(dir->i_sb))
1323 		buflen -= sizeof(struct ext4_dir_entry_tail);
1324 
1325 	while ((char *) de < base + buflen) {
1326 		if (ext4_check_dir_entry(dir, NULL, de, bh, base, buflen,
1327 					 ((char *)de) - base))
1328 			return -EFSCORRUPTED;
1329 		if (de->name_len && de->inode) {
1330 			if (ext4_hash_in_dirent(dir))
1331 				h.hash = EXT4_DIRENT_HASH(de);
1332 			else {
1333 				int err = ext4fs_dirhash(dir, de->name,
1334 						     de->name_len, &h);
1335 				if (err < 0)
1336 					return err;
1337 			}
1338 			map_tail--;
1339 			map_tail->hash = h.hash;
1340 			map_tail->offs = ((char *) de - base)>>2;
1341 			map_tail->size = ext4_rec_len_from_disk(de->rec_len,
1342 								blocksize);
1343 			count++;
1344 			cond_resched();
1345 		}
1346 		de = ext4_next_entry(de, blocksize);
1347 	}
1348 	return count;
1349 }
1350 
1351 /* Sort map by hash value */
dx_sort_map(struct dx_map_entry * map,unsigned count)1352 static void dx_sort_map (struct dx_map_entry *map, unsigned count)
1353 {
1354 	struct dx_map_entry *p, *q, *top = map + count - 1;
1355 	int more;
1356 	/* Combsort until bubble sort doesn't suck */
1357 	while (count > 2) {
1358 		count = count*10/13;
1359 		if (count - 9 < 2) /* 9, 10 -> 11 */
1360 			count = 11;
1361 		for (p = top, q = p - count; q >= map; p--, q--)
1362 			if (p->hash < q->hash)
1363 				swap(*p, *q);
1364 	}
1365 	/* Garden variety bubble sort */
1366 	do {
1367 		more = 0;
1368 		q = top;
1369 		while (q-- > map) {
1370 			if (q[1].hash >= q[0].hash)
1371 				continue;
1372 			swap(*(q+1), *q);
1373 			more = 1;
1374 		}
1375 	} while(more);
1376 }
1377 
dx_insert_block(struct dx_frame * frame,u32 hash,ext4_lblk_t block)1378 static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
1379 {
1380 	struct dx_entry *entries = frame->entries;
1381 	struct dx_entry *old = frame->at, *new = old + 1;
1382 	int count = dx_get_count(entries);
1383 
1384 	ASSERT(count < dx_get_limit(entries));
1385 	ASSERT(old < entries + count);
1386 	memmove(new + 1, new, (char *)(entries + count) - (char *)(new));
1387 	dx_set_hash(new, hash);
1388 	dx_set_block(new, block);
1389 	dx_set_count(entries, count + 1);
1390 }
1391 
1392 #if IS_ENABLED(CONFIG_UNICODE)
1393 /*
1394  * Test whether a case-insensitive directory entry matches the filename
1395  * being searched for.  If quick is set, assume the name being looked up
1396  * is already in the casefolded form.
1397  *
1398  * Returns: 0 if the directory entry matches, more than 0 if it
1399  * doesn't match or less than zero on error.
1400  */
ext4_ci_compare(const struct inode * parent,const struct qstr * name,u8 * de_name,size_t de_name_len,bool quick)1401 static int ext4_ci_compare(const struct inode *parent, const struct qstr *name,
1402 			   u8 *de_name, size_t de_name_len, bool quick)
1403 {
1404 	const struct super_block *sb = parent->i_sb;
1405 	const struct unicode_map *um = sb->s_encoding;
1406 	struct fscrypt_str decrypted_name = FSTR_INIT(NULL, de_name_len);
1407 	struct qstr entry = QSTR_INIT(de_name, de_name_len);
1408 	int ret;
1409 
1410 	if (IS_ENCRYPTED(parent)) {
1411 		const struct fscrypt_str encrypted_name =
1412 				FSTR_INIT(de_name, de_name_len);
1413 
1414 		decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL);
1415 		if (!decrypted_name.name)
1416 			return -ENOMEM;
1417 		ret = fscrypt_fname_disk_to_usr(parent, 0, 0, &encrypted_name,
1418 						&decrypted_name);
1419 		if (ret < 0)
1420 			goto out;
1421 		entry.name = decrypted_name.name;
1422 		entry.len = decrypted_name.len;
1423 	}
1424 
1425 	if (quick)
1426 		ret = utf8_strncasecmp_folded(um, name, &entry);
1427 	else
1428 		ret = utf8_strncasecmp(um, name, &entry);
1429 	if (ret < 0) {
1430 		/* Handle invalid character sequence as either an error
1431 		 * or as an opaque byte sequence.
1432 		 */
1433 		if (sb_has_strict_encoding(sb))
1434 			ret = -EINVAL;
1435 		else if (name->len != entry.len)
1436 			ret = 1;
1437 		else
1438 			ret = !!memcmp(name->name, entry.name, entry.len);
1439 	}
1440 out:
1441 	kfree(decrypted_name.name);
1442 	return ret;
1443 }
1444 
ext4_fname_setup_ci_filename(struct inode * dir,const struct qstr * iname,struct ext4_filename * name)1445 int ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
1446 				  struct ext4_filename *name)
1447 {
1448 	struct fscrypt_str *cf_name = &name->cf_name;
1449 	struct dx_hash_info *hinfo = &name->hinfo;
1450 	int len;
1451 
1452 	if (!IS_CASEFOLDED(dir) ||
1453 	    (IS_ENCRYPTED(dir) && !fscrypt_has_encryption_key(dir))) {
1454 		cf_name->name = NULL;
1455 		return 0;
1456 	}
1457 
1458 	cf_name->name = kmalloc(EXT4_NAME_LEN, GFP_NOFS);
1459 	if (!cf_name->name)
1460 		return -ENOMEM;
1461 
1462 	len = utf8_casefold(dir->i_sb->s_encoding,
1463 			    iname, cf_name->name,
1464 			    EXT4_NAME_LEN);
1465 	if (len <= 0) {
1466 		kfree(cf_name->name);
1467 		cf_name->name = NULL;
1468 	}
1469 	cf_name->len = (unsigned) len;
1470 	if (!IS_ENCRYPTED(dir))
1471 		return 0;
1472 
1473 	hinfo->hash_version = DX_HASH_SIPHASH;
1474 	hinfo->seed = NULL;
1475 	if (cf_name->name)
1476 		return ext4fs_dirhash(dir, cf_name->name, cf_name->len, hinfo);
1477 	else
1478 		return ext4fs_dirhash(dir, iname->name, iname->len, hinfo);
1479 }
1480 #endif
1481 
1482 /*
1483  * Test whether a directory entry matches the filename being searched for.
1484  *
1485  * Return: %true if the directory entry matches, otherwise %false.
1486  */
ext4_match(struct inode * parent,const struct ext4_filename * fname,struct ext4_dir_entry_2 * de)1487 static bool ext4_match(struct inode *parent,
1488 			      const struct ext4_filename *fname,
1489 			      struct ext4_dir_entry_2 *de)
1490 {
1491 	struct fscrypt_name f;
1492 
1493 	if (!de->inode)
1494 		return false;
1495 
1496 	f.usr_fname = fname->usr_fname;
1497 	f.disk_name = fname->disk_name;
1498 #ifdef CONFIG_FS_ENCRYPTION
1499 	f.crypto_buf = fname->crypto_buf;
1500 #endif
1501 
1502 #if IS_ENABLED(CONFIG_UNICODE)
1503 	if (IS_CASEFOLDED(parent) &&
1504 	    (!IS_ENCRYPTED(parent) || fscrypt_has_encryption_key(parent))) {
1505 		if (fname->cf_name.name) {
1506 			struct qstr cf = {.name = fname->cf_name.name,
1507 					  .len = fname->cf_name.len};
1508 			if (IS_ENCRYPTED(parent)) {
1509 				if (fname->hinfo.hash != EXT4_DIRENT_HASH(de) ||
1510 					fname->hinfo.minor_hash !=
1511 						EXT4_DIRENT_MINOR_HASH(de)) {
1512 
1513 					return false;
1514 				}
1515 			}
1516 			return !ext4_ci_compare(parent, &cf, de->name,
1517 							de->name_len, true);
1518 		}
1519 		return !ext4_ci_compare(parent, fname->usr_fname, de->name,
1520 						de->name_len, false);
1521 	}
1522 #endif
1523 
1524 	return fscrypt_match_name(&f, de->name, de->name_len);
1525 }
1526 
1527 /*
1528  * Returns 0 if not found, -1 on failure, and 1 on success
1529  */
ext4_search_dir(struct buffer_head * bh,char * search_buf,int buf_size,struct inode * dir,struct ext4_filename * fname,unsigned int offset,struct ext4_dir_entry_2 ** res_dir)1530 int ext4_search_dir(struct buffer_head *bh, char *search_buf, int buf_size,
1531 		    struct inode *dir, struct ext4_filename *fname,
1532 		    unsigned int offset, struct ext4_dir_entry_2 **res_dir)
1533 {
1534 	struct ext4_dir_entry_2 * de;
1535 	char * dlimit;
1536 	int de_len;
1537 
1538 	de = (struct ext4_dir_entry_2 *)search_buf;
1539 	dlimit = search_buf + buf_size;
1540 	while ((char *) de < dlimit - EXT4_BASE_DIR_LEN) {
1541 		/* this code is executed quadratically often */
1542 		/* do minimal checking `by hand' */
1543 		if (de->name + de->name_len <= dlimit &&
1544 		    ext4_match(dir, fname, de)) {
1545 			/* found a match - just to be sure, do
1546 			 * a full check */
1547 			if (ext4_check_dir_entry(dir, NULL, de, bh, search_buf,
1548 						 buf_size, offset))
1549 				return -1;
1550 			*res_dir = de;
1551 			return 1;
1552 		}
1553 		/* prevent looping on a bad block */
1554 		de_len = ext4_rec_len_from_disk(de->rec_len,
1555 						dir->i_sb->s_blocksize);
1556 		if (de_len <= 0)
1557 			return -1;
1558 		offset += de_len;
1559 		de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
1560 	}
1561 	return 0;
1562 }
1563 
is_dx_internal_node(struct inode * dir,ext4_lblk_t block,struct ext4_dir_entry * de)1564 static int is_dx_internal_node(struct inode *dir, ext4_lblk_t block,
1565 			       struct ext4_dir_entry *de)
1566 {
1567 	struct super_block *sb = dir->i_sb;
1568 
1569 	if (!is_dx(dir))
1570 		return 0;
1571 	if (block == 0)
1572 		return 1;
1573 	if (de->inode == 0 &&
1574 	    ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) ==
1575 			sb->s_blocksize)
1576 		return 1;
1577 	return 0;
1578 }
1579 
1580 /*
1581  *	__ext4_find_entry()
1582  *
1583  * finds an entry in the specified directory with the wanted name. It
1584  * returns the cache buffer in which the entry was found, and the entry
1585  * itself (as a parameter - res_dir). It does NOT read the inode of the
1586  * entry - you'll have to do that yourself if you want to.
1587  *
1588  * The returned buffer_head has ->b_count elevated.  The caller is expected
1589  * to brelse() it when appropriate.
1590  */
__ext4_find_entry(struct inode * dir,struct ext4_filename * fname,struct ext4_dir_entry_2 ** res_dir,int * inlined)1591 static struct buffer_head *__ext4_find_entry(struct inode *dir,
1592 					     struct ext4_filename *fname,
1593 					     struct ext4_dir_entry_2 **res_dir,
1594 					     int *inlined)
1595 {
1596 	struct super_block *sb;
1597 	struct buffer_head *bh_use[NAMEI_RA_SIZE];
1598 	struct buffer_head *bh, *ret = NULL;
1599 	ext4_lblk_t start, block;
1600 	const u8 *name = fname->usr_fname->name;
1601 	size_t ra_max = 0;	/* Number of bh's in the readahead
1602 				   buffer, bh_use[] */
1603 	size_t ra_ptr = 0;	/* Current index into readahead
1604 				   buffer */
1605 	ext4_lblk_t  nblocks;
1606 	int i, namelen, retval;
1607 
1608 	*res_dir = NULL;
1609 	sb = dir->i_sb;
1610 	namelen = fname->usr_fname->len;
1611 	if (namelen > EXT4_NAME_LEN)
1612 		return NULL;
1613 
1614 	if (ext4_has_inline_data(dir)) {
1615 		int has_inline_data = 1;
1616 		ret = ext4_find_inline_entry(dir, fname, res_dir,
1617 					     &has_inline_data);
1618 		if (inlined)
1619 			*inlined = has_inline_data;
1620 		if (has_inline_data)
1621 			goto cleanup_and_exit;
1622 	}
1623 
1624 	if ((namelen <= 2) && (name[0] == '.') &&
1625 	    (name[1] == '.' || name[1] == '\0')) {
1626 		/*
1627 		 * "." or ".." will only be in the first block
1628 		 * NFS may look up ".."; "." should be handled by the VFS
1629 		 */
1630 		block = start = 0;
1631 		nblocks = 1;
1632 		goto restart;
1633 	}
1634 	if (is_dx(dir)) {
1635 		ret = ext4_dx_find_entry(dir, fname, res_dir);
1636 		/*
1637 		 * On success, or if the error was file not found,
1638 		 * return.  Otherwise, fall back to doing a search the
1639 		 * old fashioned way.
1640 		 */
1641 		if (!IS_ERR(ret) || PTR_ERR(ret) != ERR_BAD_DX_DIR)
1642 			goto cleanup_and_exit;
1643 		dxtrace(printk(KERN_DEBUG "ext4_find_entry: dx failed, "
1644 			       "falling back\n"));
1645 		ret = NULL;
1646 	}
1647 	nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1648 	if (!nblocks) {
1649 		ret = NULL;
1650 		goto cleanup_and_exit;
1651 	}
1652 	start = EXT4_I(dir)->i_dir_start_lookup;
1653 	if (start >= nblocks)
1654 		start = 0;
1655 	block = start;
1656 restart:
1657 	do {
1658 		/*
1659 		 * We deal with the read-ahead logic here.
1660 		 */
1661 		cond_resched();
1662 		if (ra_ptr >= ra_max) {
1663 			/* Refill the readahead buffer */
1664 			ra_ptr = 0;
1665 			if (block < start)
1666 				ra_max = start - block;
1667 			else
1668 				ra_max = nblocks - block;
1669 			ra_max = min(ra_max, ARRAY_SIZE(bh_use));
1670 			retval = ext4_bread_batch(dir, block, ra_max,
1671 						  false /* wait */, bh_use);
1672 			if (retval) {
1673 				ret = ERR_PTR(retval);
1674 				ra_max = 0;
1675 				goto cleanup_and_exit;
1676 			}
1677 		}
1678 		if ((bh = bh_use[ra_ptr++]) == NULL)
1679 			goto next;
1680 		wait_on_buffer(bh);
1681 		if (!buffer_uptodate(bh)) {
1682 			EXT4_ERROR_INODE_ERR(dir, EIO,
1683 					     "reading directory lblock %lu",
1684 					     (unsigned long) block);
1685 			brelse(bh);
1686 			ret = ERR_PTR(-EIO);
1687 			goto cleanup_and_exit;
1688 		}
1689 		if (!buffer_verified(bh) &&
1690 		    !is_dx_internal_node(dir, block,
1691 					 (struct ext4_dir_entry *)bh->b_data) &&
1692 		    !ext4_dirblock_csum_verify(dir, bh)) {
1693 			EXT4_ERROR_INODE_ERR(dir, EFSBADCRC,
1694 					     "checksumming directory "
1695 					     "block %lu", (unsigned long)block);
1696 			brelse(bh);
1697 			ret = ERR_PTR(-EFSBADCRC);
1698 			goto cleanup_and_exit;
1699 		}
1700 		set_buffer_verified(bh);
1701 		i = search_dirblock(bh, dir, fname,
1702 			    block << EXT4_BLOCK_SIZE_BITS(sb), res_dir);
1703 		if (i == 1) {
1704 			EXT4_I(dir)->i_dir_start_lookup = block;
1705 			ret = bh;
1706 			goto cleanup_and_exit;
1707 		} else {
1708 			brelse(bh);
1709 			if (i < 0)
1710 				goto cleanup_and_exit;
1711 		}
1712 	next:
1713 		if (++block >= nblocks)
1714 			block = 0;
1715 	} while (block != start);
1716 
1717 	/*
1718 	 * If the directory has grown while we were searching, then
1719 	 * search the last part of the directory before giving up.
1720 	 */
1721 	block = nblocks;
1722 	nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1723 	if (block < nblocks) {
1724 		start = 0;
1725 		goto restart;
1726 	}
1727 
1728 cleanup_and_exit:
1729 	/* Clean up the read-ahead blocks */
1730 	for (; ra_ptr < ra_max; ra_ptr++)
1731 		brelse(bh_use[ra_ptr]);
1732 	return ret;
1733 }
1734 
ext4_find_entry(struct inode * dir,const struct qstr * d_name,struct ext4_dir_entry_2 ** res_dir,int * inlined)1735 static struct buffer_head *ext4_find_entry(struct inode *dir,
1736 					   const struct qstr *d_name,
1737 					   struct ext4_dir_entry_2 **res_dir,
1738 					   int *inlined)
1739 {
1740 	int err;
1741 	struct ext4_filename fname;
1742 	struct buffer_head *bh;
1743 
1744 	err = ext4_fname_setup_filename(dir, d_name, 1, &fname);
1745 	if (err == -ENOENT)
1746 		return NULL;
1747 	if (err)
1748 		return ERR_PTR(err);
1749 
1750 	bh = __ext4_find_entry(dir, &fname, res_dir, inlined);
1751 
1752 	ext4_fname_free_filename(&fname);
1753 	return bh;
1754 }
1755 
ext4_lookup_entry(struct inode * dir,struct dentry * dentry,struct ext4_dir_entry_2 ** res_dir)1756 static struct buffer_head *ext4_lookup_entry(struct inode *dir,
1757 					     struct dentry *dentry,
1758 					     struct ext4_dir_entry_2 **res_dir)
1759 {
1760 	int err;
1761 	struct ext4_filename fname;
1762 	struct buffer_head *bh;
1763 
1764 	err = ext4_fname_prepare_lookup(dir, dentry, &fname);
1765 	generic_set_encrypted_ci_d_ops(dentry);
1766 	if (err == -ENOENT)
1767 		return NULL;
1768 	if (err)
1769 		return ERR_PTR(err);
1770 
1771 	bh = __ext4_find_entry(dir, &fname, res_dir, NULL);
1772 
1773 	ext4_fname_free_filename(&fname);
1774 	return bh;
1775 }
1776 
ext4_dx_find_entry(struct inode * dir,struct ext4_filename * fname,struct ext4_dir_entry_2 ** res_dir)1777 static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
1778 			struct ext4_filename *fname,
1779 			struct ext4_dir_entry_2 **res_dir)
1780 {
1781 	struct super_block * sb = dir->i_sb;
1782 	struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
1783 	struct buffer_head *bh;
1784 	ext4_lblk_t block;
1785 	int retval;
1786 
1787 #ifdef CONFIG_FS_ENCRYPTION
1788 	*res_dir = NULL;
1789 #endif
1790 	frame = dx_probe(fname, dir, NULL, frames);
1791 	if (IS_ERR(frame))
1792 		return (struct buffer_head *) frame;
1793 	do {
1794 		block = dx_get_block(frame->at);
1795 		bh = ext4_read_dirblock(dir, block, DIRENT_HTREE);
1796 		if (IS_ERR(bh))
1797 			goto errout;
1798 
1799 		retval = search_dirblock(bh, dir, fname,
1800 					 block << EXT4_BLOCK_SIZE_BITS(sb),
1801 					 res_dir);
1802 		if (retval == 1)
1803 			goto success;
1804 		brelse(bh);
1805 		if (retval == -1) {
1806 			bh = ERR_PTR(ERR_BAD_DX_DIR);
1807 			goto errout;
1808 		}
1809 
1810 		/* Check to see if we should continue to search */
1811 		retval = ext4_htree_next_block(dir, fname->hinfo.hash, frame,
1812 					       frames, NULL);
1813 		if (retval < 0) {
1814 			ext4_warning_inode(dir,
1815 				"error %d reading directory index block",
1816 				retval);
1817 			bh = ERR_PTR(retval);
1818 			goto errout;
1819 		}
1820 	} while (retval == 1);
1821 
1822 	bh = NULL;
1823 errout:
1824 	dxtrace(printk(KERN_DEBUG "%s not found\n", fname->usr_fname->name));
1825 success:
1826 	dx_release(frames);
1827 	return bh;
1828 }
1829 
ext4_lookup(struct inode * dir,struct dentry * dentry,unsigned int flags)1830 static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
1831 {
1832 	struct inode *inode;
1833 	struct ext4_dir_entry_2 *de;
1834 	struct buffer_head *bh;
1835 
1836 	if (dentry->d_name.len > EXT4_NAME_LEN)
1837 		return ERR_PTR(-ENAMETOOLONG);
1838 
1839 	bh = ext4_lookup_entry(dir, dentry, &de);
1840 	if (IS_ERR(bh))
1841 		return ERR_CAST(bh);
1842 	inode = NULL;
1843 	if (bh) {
1844 		__u32 ino = le32_to_cpu(de->inode);
1845 		brelse(bh);
1846 		if (!ext4_valid_inum(dir->i_sb, ino)) {
1847 			EXT4_ERROR_INODE(dir, "bad inode number: %u", ino);
1848 			return ERR_PTR(-EFSCORRUPTED);
1849 		}
1850 		if (unlikely(ino == dir->i_ino)) {
1851 			EXT4_ERROR_INODE(dir, "'%pd' linked to parent dir",
1852 					 dentry);
1853 			return ERR_PTR(-EFSCORRUPTED);
1854 		}
1855 		inode = ext4_iget(dir->i_sb, ino, EXT4_IGET_NORMAL);
1856 		if (inode == ERR_PTR(-ESTALE)) {
1857 			EXT4_ERROR_INODE(dir,
1858 					 "deleted inode referenced: %u",
1859 					 ino);
1860 			return ERR_PTR(-EFSCORRUPTED);
1861 		}
1862 		if (!IS_ERR(inode) && IS_ENCRYPTED(dir) &&
1863 		    (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) &&
1864 		    !fscrypt_has_permitted_context(dir, inode)) {
1865 			ext4_warning(inode->i_sb,
1866 				     "Inconsistent encryption contexts: %lu/%lu",
1867 				     dir->i_ino, inode->i_ino);
1868 			iput(inode);
1869 			return ERR_PTR(-EPERM);
1870 		}
1871 	}
1872 
1873 #if IS_ENABLED(CONFIG_UNICODE)
1874 	if (!inode && IS_CASEFOLDED(dir)) {
1875 		/* Eventually we want to call d_add_ci(dentry, NULL)
1876 		 * for negative dentries in the encoding case as
1877 		 * well.  For now, prevent the negative dentry
1878 		 * from being cached.
1879 		 */
1880 		return NULL;
1881 	}
1882 #endif
1883 	return d_splice_alias(inode, dentry);
1884 }
1885 
1886 
ext4_get_parent(struct dentry * child)1887 struct dentry *ext4_get_parent(struct dentry *child)
1888 {
1889 	__u32 ino;
1890 	struct ext4_dir_entry_2 * de;
1891 	struct buffer_head *bh;
1892 
1893 	bh = ext4_find_entry(d_inode(child), &dotdot_name, &de, NULL);
1894 	if (IS_ERR(bh))
1895 		return ERR_CAST(bh);
1896 	if (!bh)
1897 		return ERR_PTR(-ENOENT);
1898 	ino = le32_to_cpu(de->inode);
1899 	brelse(bh);
1900 
1901 	if (!ext4_valid_inum(child->d_sb, ino)) {
1902 		EXT4_ERROR_INODE(d_inode(child),
1903 				 "bad parent inode number: %u", ino);
1904 		return ERR_PTR(-EFSCORRUPTED);
1905 	}
1906 
1907 	return d_obtain_alias(ext4_iget(child->d_sb, ino, EXT4_IGET_NORMAL));
1908 }
1909 
1910 /*
1911  * Move count entries from end of map between two memory locations.
1912  * Returns pointer to last entry moved.
1913  */
1914 static struct ext4_dir_entry_2 *
dx_move_dirents(struct inode * dir,char * from,char * to,struct dx_map_entry * map,int count,unsigned blocksize)1915 dx_move_dirents(struct inode *dir, char *from, char *to,
1916 		struct dx_map_entry *map, int count,
1917 		unsigned blocksize)
1918 {
1919 	unsigned rec_len = 0;
1920 
1921 	while (count--) {
1922 		struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)
1923 						(from + (map->offs<<2));
1924 		rec_len = ext4_dir_rec_len(de->name_len, dir);
1925 
1926 		memcpy (to, de, rec_len);
1927 		((struct ext4_dir_entry_2 *) to)->rec_len =
1928 				ext4_rec_len_to_disk(rec_len, blocksize);
1929 
1930 		/* wipe dir_entry excluding the rec_len field */
1931 		de->inode = 0;
1932 		memset(&de->name_len, 0, ext4_rec_len_from_disk(de->rec_len,
1933 								blocksize) -
1934 					 offsetof(struct ext4_dir_entry_2,
1935 								name_len));
1936 
1937 		map++;
1938 		to += rec_len;
1939 	}
1940 	return (struct ext4_dir_entry_2 *) (to - rec_len);
1941 }
1942 
1943 /*
1944  * Compact each dir entry in the range to the minimal rec_len.
1945  * Returns pointer to last entry in range.
1946  */
dx_pack_dirents(struct inode * dir,char * base,unsigned int blocksize)1947 static struct ext4_dir_entry_2 *dx_pack_dirents(struct inode *dir, char *base,
1948 							unsigned int blocksize)
1949 {
1950 	struct ext4_dir_entry_2 *next, *to, *prev, *de = (struct ext4_dir_entry_2 *) base;
1951 	unsigned rec_len = 0;
1952 
1953 	prev = to = de;
1954 	while ((char*)de < base + blocksize) {
1955 		next = ext4_next_entry(de, blocksize);
1956 		if (de->inode && de->name_len) {
1957 			rec_len = ext4_dir_rec_len(de->name_len, dir);
1958 			if (de > to)
1959 				memmove(to, de, rec_len);
1960 			to->rec_len = ext4_rec_len_to_disk(rec_len, blocksize);
1961 			prev = to;
1962 			to = (struct ext4_dir_entry_2 *) (((char *) to) + rec_len);
1963 		}
1964 		de = next;
1965 	}
1966 	return prev;
1967 }
1968 
1969 /*
1970  * Split a full leaf block to make room for a new dir entry.
1971  * Allocate a new block, and move entries so that they are approx. equally full.
1972  * Returns pointer to de in block into which the new entry will be inserted.
1973  */
do_split(handle_t * handle,struct inode * dir,struct buffer_head ** bh,struct dx_frame * frame,struct dx_hash_info * hinfo)1974 static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
1975 			struct buffer_head **bh,struct dx_frame *frame,
1976 			struct dx_hash_info *hinfo)
1977 {
1978 	unsigned blocksize = dir->i_sb->s_blocksize;
1979 	unsigned continued;
1980 	int count;
1981 	struct buffer_head *bh2;
1982 	ext4_lblk_t newblock;
1983 	u32 hash2;
1984 	struct dx_map_entry *map;
1985 	char *data1 = (*bh)->b_data, *data2;
1986 	unsigned split, move, size;
1987 	struct ext4_dir_entry_2 *de = NULL, *de2;
1988 	int	csum_size = 0;
1989 	int	err = 0, i;
1990 
1991 	if (ext4_has_metadata_csum(dir->i_sb))
1992 		csum_size = sizeof(struct ext4_dir_entry_tail);
1993 
1994 	bh2 = ext4_append(handle, dir, &newblock);
1995 	if (IS_ERR(bh2)) {
1996 		brelse(*bh);
1997 		*bh = NULL;
1998 		return (struct ext4_dir_entry_2 *) bh2;
1999 	}
2000 
2001 	BUFFER_TRACE(*bh, "get_write_access");
2002 	err = ext4_journal_get_write_access(handle, dir->i_sb, *bh,
2003 					    EXT4_JTR_NONE);
2004 	if (err)
2005 		goto journal_error;
2006 
2007 	BUFFER_TRACE(frame->bh, "get_write_access");
2008 	err = ext4_journal_get_write_access(handle, dir->i_sb, frame->bh,
2009 					    EXT4_JTR_NONE);
2010 	if (err)
2011 		goto journal_error;
2012 
2013 	data2 = bh2->b_data;
2014 
2015 	/* create map in the end of data2 block */
2016 	map = (struct dx_map_entry *) (data2 + blocksize);
2017 	count = dx_make_map(dir, *bh, hinfo, map);
2018 	if (count < 0) {
2019 		err = count;
2020 		goto journal_error;
2021 	}
2022 	map -= count;
2023 	dx_sort_map(map, count);
2024 	/* Ensure that neither split block is over half full */
2025 	size = 0;
2026 	move = 0;
2027 	for (i = count-1; i >= 0; i--) {
2028 		/* is more than half of this entry in 2nd half of the block? */
2029 		if (size + map[i].size/2 > blocksize/2)
2030 			break;
2031 		size += map[i].size;
2032 		move++;
2033 	}
2034 	/*
2035 	 * map index at which we will split
2036 	 *
2037 	 * If the sum of active entries didn't exceed half the block size, just
2038 	 * split it in half by count; each resulting block will have at least
2039 	 * half the space free.
2040 	 */
2041 	if (i > 0)
2042 		split = count - move;
2043 	else
2044 		split = count/2;
2045 
2046 	hash2 = map[split].hash;
2047 	continued = hash2 == map[split - 1].hash;
2048 	dxtrace(printk(KERN_INFO "Split block %lu at %x, %i/%i\n",
2049 			(unsigned long)dx_get_block(frame->at),
2050 					hash2, split, count-split));
2051 
2052 	/* Fancy dance to stay within two buffers */
2053 	de2 = dx_move_dirents(dir, data1, data2, map + split, count - split,
2054 			      blocksize);
2055 	de = dx_pack_dirents(dir, data1, blocksize);
2056 	de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
2057 					   (char *) de,
2058 					   blocksize);
2059 	de2->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
2060 					    (char *) de2,
2061 					    blocksize);
2062 	if (csum_size) {
2063 		ext4_initialize_dirent_tail(*bh, blocksize);
2064 		ext4_initialize_dirent_tail(bh2, blocksize);
2065 	}
2066 
2067 	dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data1,
2068 			blocksize, 1));
2069 	dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data2,
2070 			blocksize, 1));
2071 
2072 	/* Which block gets the new entry? */
2073 	if (hinfo->hash >= hash2) {
2074 		swap(*bh, bh2);
2075 		de = de2;
2076 	}
2077 	dx_insert_block(frame, hash2 + continued, newblock);
2078 	err = ext4_handle_dirty_dirblock(handle, dir, bh2);
2079 	if (err)
2080 		goto journal_error;
2081 	err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
2082 	if (err)
2083 		goto journal_error;
2084 	brelse(bh2);
2085 	dxtrace(dx_show_index("frame", frame->entries));
2086 	return de;
2087 
2088 journal_error:
2089 	brelse(*bh);
2090 	brelse(bh2);
2091 	*bh = NULL;
2092 	ext4_std_error(dir->i_sb, err);
2093 	return ERR_PTR(err);
2094 }
2095 
ext4_find_dest_de(struct inode * dir,struct inode * inode,struct buffer_head * bh,void * buf,int buf_size,struct ext4_filename * fname,struct ext4_dir_entry_2 ** dest_de)2096 int ext4_find_dest_de(struct inode *dir, struct inode *inode,
2097 		      struct buffer_head *bh,
2098 		      void *buf, int buf_size,
2099 		      struct ext4_filename *fname,
2100 		      struct ext4_dir_entry_2 **dest_de)
2101 {
2102 	struct ext4_dir_entry_2 *de;
2103 	unsigned short reclen = ext4_dir_rec_len(fname_len(fname), dir);
2104 	int nlen, rlen;
2105 	unsigned int offset = 0;
2106 	char *top;
2107 
2108 	de = buf;
2109 	top = buf + buf_size - reclen;
2110 	while ((char *) de <= top) {
2111 		if (ext4_check_dir_entry(dir, NULL, de, bh,
2112 					 buf, buf_size, offset))
2113 			return -EFSCORRUPTED;
2114 		if (ext4_match(dir, fname, de))
2115 			return -EEXIST;
2116 		nlen = ext4_dir_rec_len(de->name_len, dir);
2117 		rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
2118 		if ((de->inode ? rlen - nlen : rlen) >= reclen)
2119 			break;
2120 		de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
2121 		offset += rlen;
2122 	}
2123 	if ((char *) de > top)
2124 		return -ENOSPC;
2125 
2126 	*dest_de = de;
2127 	return 0;
2128 }
2129 
ext4_insert_dentry(struct inode * dir,struct inode * inode,struct ext4_dir_entry_2 * de,int buf_size,struct ext4_filename * fname)2130 void ext4_insert_dentry(struct inode *dir,
2131 			struct inode *inode,
2132 			struct ext4_dir_entry_2 *de,
2133 			int buf_size,
2134 			struct ext4_filename *fname)
2135 {
2136 
2137 	int nlen, rlen;
2138 
2139 	nlen = ext4_dir_rec_len(de->name_len, dir);
2140 	rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
2141 	if (de->inode) {
2142 		struct ext4_dir_entry_2 *de1 =
2143 			(struct ext4_dir_entry_2 *)((char *)de + nlen);
2144 		de1->rec_len = ext4_rec_len_to_disk(rlen - nlen, buf_size);
2145 		de->rec_len = ext4_rec_len_to_disk(nlen, buf_size);
2146 		de = de1;
2147 	}
2148 	de->file_type = EXT4_FT_UNKNOWN;
2149 	de->inode = cpu_to_le32(inode->i_ino);
2150 	ext4_set_de_type(inode->i_sb, de, inode->i_mode);
2151 	de->name_len = fname_len(fname);
2152 	memcpy(de->name, fname_name(fname), fname_len(fname));
2153 	if (ext4_hash_in_dirent(dir)) {
2154 		struct dx_hash_info *hinfo = &fname->hinfo;
2155 
2156 		EXT4_DIRENT_HASHES(de)->hash = cpu_to_le32(hinfo->hash);
2157 		EXT4_DIRENT_HASHES(de)->minor_hash =
2158 						cpu_to_le32(hinfo->minor_hash);
2159 	}
2160 }
2161 
2162 /*
2163  * Add a new entry into a directory (leaf) block.  If de is non-NULL,
2164  * it points to a directory entry which is guaranteed to be large
2165  * enough for new directory entry.  If de is NULL, then
2166  * add_dirent_to_buf will attempt search the directory block for
2167  * space.  It will return -ENOSPC if no space is available, and -EIO
2168  * and -EEXIST if directory entry already exists.
2169  */
add_dirent_to_buf(handle_t * handle,struct ext4_filename * fname,struct inode * dir,struct inode * inode,struct ext4_dir_entry_2 * de,struct buffer_head * bh)2170 static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
2171 			     struct inode *dir,
2172 			     struct inode *inode, struct ext4_dir_entry_2 *de,
2173 			     struct buffer_head *bh)
2174 {
2175 	unsigned int	blocksize = dir->i_sb->s_blocksize;
2176 	int		csum_size = 0;
2177 	int		err, err2;
2178 
2179 	if (ext4_has_metadata_csum(inode->i_sb))
2180 		csum_size = sizeof(struct ext4_dir_entry_tail);
2181 
2182 	if (!de) {
2183 		err = ext4_find_dest_de(dir, inode, bh, bh->b_data,
2184 					blocksize - csum_size, fname, &de);
2185 		if (err)
2186 			return err;
2187 	}
2188 	BUFFER_TRACE(bh, "get_write_access");
2189 	err = ext4_journal_get_write_access(handle, dir->i_sb, bh,
2190 					    EXT4_JTR_NONE);
2191 	if (err) {
2192 		ext4_std_error(dir->i_sb, err);
2193 		return err;
2194 	}
2195 
2196 	/* By now the buffer is marked for journaling */
2197 	ext4_insert_dentry(dir, inode, de, blocksize, fname);
2198 
2199 	/*
2200 	 * XXX shouldn't update any times until successful
2201 	 * completion of syscall, but too many callers depend
2202 	 * on this.
2203 	 *
2204 	 * XXX similarly, too many callers depend on
2205 	 * ext4_new_inode() setting the times, but error
2206 	 * recovery deletes the inode, so the worst that can
2207 	 * happen is that the times are slightly out of date
2208 	 * and/or different from the directory change time.
2209 	 */
2210 	dir->i_mtime = inode_set_ctime_current(dir);
2211 	ext4_update_dx_flag(dir);
2212 	inode_inc_iversion(dir);
2213 	err2 = ext4_mark_inode_dirty(handle, dir);
2214 	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
2215 	err = ext4_handle_dirty_dirblock(handle, dir, bh);
2216 	if (err)
2217 		ext4_std_error(dir->i_sb, err);
2218 	return err ? err : err2;
2219 }
2220 
2221 /*
2222  * This converts a one block unindexed directory to a 3 block indexed
2223  * directory, and adds the dentry to the indexed directory.
2224  */
make_indexed_dir(handle_t * handle,struct ext4_filename * fname,struct inode * dir,struct inode * inode,struct buffer_head * bh)2225 static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
2226 			    struct inode *dir,
2227 			    struct inode *inode, struct buffer_head *bh)
2228 {
2229 	struct buffer_head *bh2;
2230 	struct dx_root	*root;
2231 	struct dx_frame	frames[EXT4_HTREE_LEVEL], *frame;
2232 	struct dx_entry *entries;
2233 	struct ext4_dir_entry_2	*de, *de2;
2234 	char		*data2, *top;
2235 	unsigned	len;
2236 	int		retval;
2237 	unsigned	blocksize;
2238 	ext4_lblk_t  block;
2239 	struct fake_dirent *fde;
2240 	int csum_size = 0;
2241 
2242 	if (ext4_has_metadata_csum(inode->i_sb))
2243 		csum_size = sizeof(struct ext4_dir_entry_tail);
2244 
2245 	blocksize =  dir->i_sb->s_blocksize;
2246 	dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino));
2247 	BUFFER_TRACE(bh, "get_write_access");
2248 	retval = ext4_journal_get_write_access(handle, dir->i_sb, bh,
2249 					       EXT4_JTR_NONE);
2250 	if (retval) {
2251 		ext4_std_error(dir->i_sb, retval);
2252 		brelse(bh);
2253 		return retval;
2254 	}
2255 	root = (struct dx_root *) bh->b_data;
2256 
2257 	/* The 0th block becomes the root, move the dirents out */
2258 	fde = &root->dotdot;
2259 	de = (struct ext4_dir_entry_2 *)((char *)fde +
2260 		ext4_rec_len_from_disk(fde->rec_len, blocksize));
2261 	if ((char *) de >= (((char *) root) + blocksize)) {
2262 		EXT4_ERROR_INODE(dir, "invalid rec_len for '..'");
2263 		brelse(bh);
2264 		return -EFSCORRUPTED;
2265 	}
2266 	len = ((char *) root) + (blocksize - csum_size) - (char *) de;
2267 
2268 	/* Allocate new block for the 0th block's dirents */
2269 	bh2 = ext4_append(handle, dir, &block);
2270 	if (IS_ERR(bh2)) {
2271 		brelse(bh);
2272 		return PTR_ERR(bh2);
2273 	}
2274 	ext4_set_inode_flag(dir, EXT4_INODE_INDEX);
2275 	data2 = bh2->b_data;
2276 
2277 	memcpy(data2, de, len);
2278 	memset(de, 0, len); /* wipe old data */
2279 	de = (struct ext4_dir_entry_2 *) data2;
2280 	top = data2 + len;
2281 	while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top) {
2282 		if (ext4_check_dir_entry(dir, NULL, de, bh2, data2, len,
2283 					 (data2 + (blocksize - csum_size) -
2284 					  (char *) de))) {
2285 			brelse(bh2);
2286 			brelse(bh);
2287 			return -EFSCORRUPTED;
2288 		}
2289 		de = de2;
2290 	}
2291 	de->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
2292 					   (char *) de, blocksize);
2293 
2294 	if (csum_size)
2295 		ext4_initialize_dirent_tail(bh2, blocksize);
2296 
2297 	/* Initialize the root; the dot dirents already exist */
2298 	de = (struct ext4_dir_entry_2 *) (&root->dotdot);
2299 	de->rec_len = ext4_rec_len_to_disk(
2300 			blocksize - ext4_dir_rec_len(2, NULL), blocksize);
2301 	memset (&root->info, 0, sizeof(root->info));
2302 	root->info.info_length = sizeof(root->info);
2303 	if (ext4_hash_in_dirent(dir))
2304 		root->info.hash_version = DX_HASH_SIPHASH;
2305 	else
2306 		root->info.hash_version =
2307 				EXT4_SB(dir->i_sb)->s_def_hash_version;
2308 
2309 	entries = root->entries;
2310 	dx_set_block(entries, 1);
2311 	dx_set_count(entries, 1);
2312 	dx_set_limit(entries, dx_root_limit(dir, sizeof(root->info)));
2313 
2314 	/* Initialize as for dx_probe */
2315 	fname->hinfo.hash_version = root->info.hash_version;
2316 	if (fname->hinfo.hash_version <= DX_HASH_TEA)
2317 		fname->hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
2318 	fname->hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
2319 
2320 	/* casefolded encrypted hashes are computed on fname setup */
2321 	if (!ext4_hash_in_dirent(dir)) {
2322 		int err = ext4fs_dirhash(dir, fname_name(fname),
2323 					 fname_len(fname), &fname->hinfo);
2324 		if (err < 0) {
2325 			brelse(bh2);
2326 			brelse(bh);
2327 			return err;
2328 		}
2329 	}
2330 	memset(frames, 0, sizeof(frames));
2331 	frame = frames;
2332 	frame->entries = entries;
2333 	frame->at = entries;
2334 	frame->bh = bh;
2335 
2336 	retval = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
2337 	if (retval)
2338 		goto out_frames;
2339 	retval = ext4_handle_dirty_dirblock(handle, dir, bh2);
2340 	if (retval)
2341 		goto out_frames;
2342 
2343 	de = do_split(handle,dir, &bh2, frame, &fname->hinfo);
2344 	if (IS_ERR(de)) {
2345 		retval = PTR_ERR(de);
2346 		goto out_frames;
2347 	}
2348 
2349 	retval = add_dirent_to_buf(handle, fname, dir, inode, de, bh2);
2350 out_frames:
2351 	/*
2352 	 * Even if the block split failed, we have to properly write
2353 	 * out all the changes we did so far. Otherwise we can end up
2354 	 * with corrupted filesystem.
2355 	 */
2356 	if (retval)
2357 		ext4_mark_inode_dirty(handle, dir);
2358 	dx_release(frames);
2359 	brelse(bh2);
2360 	return retval;
2361 }
2362 
2363 /*
2364  *	ext4_add_entry()
2365  *
2366  * adds a file entry to the specified directory, using the same
2367  * semantics as ext4_find_entry(). It returns NULL if it failed.
2368  *
2369  * NOTE!! The inode part of 'de' is left at 0 - which means you
2370  * may not sleep between calling this and putting something into
2371  * the entry, as someone else might have used it while you slept.
2372  */
ext4_add_entry(handle_t * handle,struct dentry * dentry,struct inode * inode)2373 static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
2374 			  struct inode *inode)
2375 {
2376 	struct inode *dir = d_inode(dentry->d_parent);
2377 	struct buffer_head *bh = NULL;
2378 	struct ext4_dir_entry_2 *de;
2379 	struct super_block *sb;
2380 	struct ext4_filename fname;
2381 	int	retval;
2382 	int	dx_fallback=0;
2383 	unsigned blocksize;
2384 	ext4_lblk_t block, blocks;
2385 	int	csum_size = 0;
2386 
2387 	if (ext4_has_metadata_csum(inode->i_sb))
2388 		csum_size = sizeof(struct ext4_dir_entry_tail);
2389 
2390 	sb = dir->i_sb;
2391 	blocksize = sb->s_blocksize;
2392 	if (!dentry->d_name.len)
2393 		return -EINVAL;
2394 
2395 	if (fscrypt_is_nokey_name(dentry))
2396 		return -ENOKEY;
2397 
2398 #if IS_ENABLED(CONFIG_UNICODE)
2399 	if (sb_has_strict_encoding(sb) && IS_CASEFOLDED(dir) &&
2400 	    utf8_validate(sb->s_encoding, &dentry->d_name))
2401 		return -EINVAL;
2402 #endif
2403 
2404 	retval = ext4_fname_setup_filename(dir, &dentry->d_name, 0, &fname);
2405 	if (retval)
2406 		return retval;
2407 
2408 	if (ext4_has_inline_data(dir)) {
2409 		retval = ext4_try_add_inline_entry(handle, &fname, dir, inode);
2410 		if (retval < 0)
2411 			goto out;
2412 		if (retval == 1) {
2413 			retval = 0;
2414 			goto out;
2415 		}
2416 	}
2417 
2418 	if (is_dx(dir)) {
2419 		retval = ext4_dx_add_entry(handle, &fname, dir, inode);
2420 		if (!retval || (retval != ERR_BAD_DX_DIR))
2421 			goto out;
2422 		/* Can we just ignore htree data? */
2423 		if (ext4_has_metadata_csum(sb)) {
2424 			EXT4_ERROR_INODE(dir,
2425 				"Directory has corrupted htree index.");
2426 			retval = -EFSCORRUPTED;
2427 			goto out;
2428 		}
2429 		ext4_clear_inode_flag(dir, EXT4_INODE_INDEX);
2430 		dx_fallback++;
2431 		retval = ext4_mark_inode_dirty(handle, dir);
2432 		if (unlikely(retval))
2433 			goto out;
2434 	}
2435 	blocks = dir->i_size >> sb->s_blocksize_bits;
2436 	for (block = 0; block < blocks; block++) {
2437 		bh = ext4_read_dirblock(dir, block, DIRENT);
2438 		if (bh == NULL) {
2439 			bh = ext4_bread(handle, dir, block,
2440 					EXT4_GET_BLOCKS_CREATE);
2441 			goto add_to_new_block;
2442 		}
2443 		if (IS_ERR(bh)) {
2444 			retval = PTR_ERR(bh);
2445 			bh = NULL;
2446 			goto out;
2447 		}
2448 		retval = add_dirent_to_buf(handle, &fname, dir, inode,
2449 					   NULL, bh);
2450 		if (retval != -ENOSPC)
2451 			goto out;
2452 
2453 		if (blocks == 1 && !dx_fallback &&
2454 		    ext4_has_feature_dir_index(sb)) {
2455 			retval = make_indexed_dir(handle, &fname, dir,
2456 						  inode, bh);
2457 			bh = NULL; /* make_indexed_dir releases bh */
2458 			goto out;
2459 		}
2460 		brelse(bh);
2461 	}
2462 	bh = ext4_append(handle, dir, &block);
2463 add_to_new_block:
2464 	if (IS_ERR(bh)) {
2465 		retval = PTR_ERR(bh);
2466 		bh = NULL;
2467 		goto out;
2468 	}
2469 	de = (struct ext4_dir_entry_2 *) bh->b_data;
2470 	de->inode = 0;
2471 	de->rec_len = ext4_rec_len_to_disk(blocksize - csum_size, blocksize);
2472 
2473 	if (csum_size)
2474 		ext4_initialize_dirent_tail(bh, blocksize);
2475 
2476 	retval = add_dirent_to_buf(handle, &fname, dir, inode, de, bh);
2477 out:
2478 	ext4_fname_free_filename(&fname);
2479 	brelse(bh);
2480 	if (retval == 0)
2481 		ext4_set_inode_state(inode, EXT4_STATE_NEWENTRY);
2482 	return retval;
2483 }
2484 
2485 /*
2486  * Returns 0 for success, or a negative error value
2487  */
ext4_dx_add_entry(handle_t * handle,struct ext4_filename * fname,struct inode * dir,struct inode * inode)2488 static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
2489 			     struct inode *dir, struct inode *inode)
2490 {
2491 	struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
2492 	struct dx_entry *entries, *at;
2493 	struct buffer_head *bh;
2494 	struct super_block *sb = dir->i_sb;
2495 	struct ext4_dir_entry_2 *de;
2496 	int restart;
2497 	int err;
2498 
2499 again:
2500 	restart = 0;
2501 	frame = dx_probe(fname, dir, NULL, frames);
2502 	if (IS_ERR(frame))
2503 		return PTR_ERR(frame);
2504 	entries = frame->entries;
2505 	at = frame->at;
2506 	bh = ext4_read_dirblock(dir, dx_get_block(frame->at), DIRENT_HTREE);
2507 	if (IS_ERR(bh)) {
2508 		err = PTR_ERR(bh);
2509 		bh = NULL;
2510 		goto cleanup;
2511 	}
2512 
2513 	BUFFER_TRACE(bh, "get_write_access");
2514 	err = ext4_journal_get_write_access(handle, sb, bh, EXT4_JTR_NONE);
2515 	if (err)
2516 		goto journal_error;
2517 
2518 	err = add_dirent_to_buf(handle, fname, dir, inode, NULL, bh);
2519 	if (err != -ENOSPC)
2520 		goto cleanup;
2521 
2522 	err = 0;
2523 	/* Block full, should compress but for now just split */
2524 	dxtrace(printk(KERN_DEBUG "using %u of %u node entries\n",
2525 		       dx_get_count(entries), dx_get_limit(entries)));
2526 	/* Need to split index? */
2527 	if (dx_get_count(entries) == dx_get_limit(entries)) {
2528 		ext4_lblk_t newblock;
2529 		int levels = frame - frames + 1;
2530 		unsigned int icount;
2531 		int add_level = 1;
2532 		struct dx_entry *entries2;
2533 		struct dx_node *node2;
2534 		struct buffer_head *bh2;
2535 
2536 		while (frame > frames) {
2537 			if (dx_get_count((frame - 1)->entries) <
2538 			    dx_get_limit((frame - 1)->entries)) {
2539 				add_level = 0;
2540 				break;
2541 			}
2542 			frame--; /* split higher index block */
2543 			at = frame->at;
2544 			entries = frame->entries;
2545 			restart = 1;
2546 		}
2547 		if (add_level && levels == ext4_dir_htree_level(sb)) {
2548 			ext4_warning(sb, "Directory (ino: %lu) index full, "
2549 					 "reach max htree level :%d",
2550 					 dir->i_ino, levels);
2551 			if (ext4_dir_htree_level(sb) < EXT4_HTREE_LEVEL) {
2552 				ext4_warning(sb, "Large directory feature is "
2553 						 "not enabled on this "
2554 						 "filesystem");
2555 			}
2556 			err = -ENOSPC;
2557 			goto cleanup;
2558 		}
2559 		icount = dx_get_count(entries);
2560 		bh2 = ext4_append(handle, dir, &newblock);
2561 		if (IS_ERR(bh2)) {
2562 			err = PTR_ERR(bh2);
2563 			goto cleanup;
2564 		}
2565 		node2 = (struct dx_node *)(bh2->b_data);
2566 		entries2 = node2->entries;
2567 		memset(&node2->fake, 0, sizeof(struct fake_dirent));
2568 		node2->fake.rec_len = ext4_rec_len_to_disk(sb->s_blocksize,
2569 							   sb->s_blocksize);
2570 		BUFFER_TRACE(frame->bh, "get_write_access");
2571 		err = ext4_journal_get_write_access(handle, sb, frame->bh,
2572 						    EXT4_JTR_NONE);
2573 		if (err)
2574 			goto journal_error;
2575 		if (!add_level) {
2576 			unsigned icount1 = icount/2, icount2 = icount - icount1;
2577 			unsigned hash2 = dx_get_hash(entries + icount1);
2578 			dxtrace(printk(KERN_DEBUG "Split index %i/%i\n",
2579 				       icount1, icount2));
2580 
2581 			BUFFER_TRACE(frame->bh, "get_write_access"); /* index root */
2582 			err = ext4_journal_get_write_access(handle, sb,
2583 							    (frame - 1)->bh,
2584 							    EXT4_JTR_NONE);
2585 			if (err)
2586 				goto journal_error;
2587 
2588 			memcpy((char *) entries2, (char *) (entries + icount1),
2589 			       icount2 * sizeof(struct dx_entry));
2590 			dx_set_count(entries, icount1);
2591 			dx_set_count(entries2, icount2);
2592 			dx_set_limit(entries2, dx_node_limit(dir));
2593 
2594 			/* Which index block gets the new entry? */
2595 			if (at - entries >= icount1) {
2596 				frame->at = at - entries - icount1 + entries2;
2597 				frame->entries = entries = entries2;
2598 				swap(frame->bh, bh2);
2599 			}
2600 			dx_insert_block((frame - 1), hash2, newblock);
2601 			dxtrace(dx_show_index("node", frame->entries));
2602 			dxtrace(dx_show_index("node",
2603 			       ((struct dx_node *) bh2->b_data)->entries));
2604 			err = ext4_handle_dirty_dx_node(handle, dir, bh2);
2605 			if (err)
2606 				goto journal_error;
2607 			brelse (bh2);
2608 			err = ext4_handle_dirty_dx_node(handle, dir,
2609 						   (frame - 1)->bh);
2610 			if (err)
2611 				goto journal_error;
2612 			err = ext4_handle_dirty_dx_node(handle, dir,
2613 							frame->bh);
2614 			if (restart || err)
2615 				goto journal_error;
2616 		} else {
2617 			struct dx_root *dxroot;
2618 			memcpy((char *) entries2, (char *) entries,
2619 			       icount * sizeof(struct dx_entry));
2620 			dx_set_limit(entries2, dx_node_limit(dir));
2621 
2622 			/* Set up root */
2623 			dx_set_count(entries, 1);
2624 			dx_set_block(entries + 0, newblock);
2625 			dxroot = (struct dx_root *)frames[0].bh->b_data;
2626 			dxroot->info.indirect_levels += 1;
2627 			dxtrace(printk(KERN_DEBUG
2628 				       "Creating %d level index...\n",
2629 				       dxroot->info.indirect_levels));
2630 			err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
2631 			if (err)
2632 				goto journal_error;
2633 			err = ext4_handle_dirty_dx_node(handle, dir, bh2);
2634 			brelse(bh2);
2635 			restart = 1;
2636 			goto journal_error;
2637 		}
2638 	}
2639 	de = do_split(handle, dir, &bh, frame, &fname->hinfo);
2640 	if (IS_ERR(de)) {
2641 		err = PTR_ERR(de);
2642 		goto cleanup;
2643 	}
2644 	err = add_dirent_to_buf(handle, fname, dir, inode, de, bh);
2645 	goto cleanup;
2646 
2647 journal_error:
2648 	ext4_std_error(dir->i_sb, err); /* this is a no-op if err == 0 */
2649 cleanup:
2650 	brelse(bh);
2651 	dx_release(frames);
2652 	/* @restart is true means htree-path has been changed, we need to
2653 	 * repeat dx_probe() to find out valid htree-path
2654 	 */
2655 	if (restart && err == 0)
2656 		goto again;
2657 	return err;
2658 }
2659 
2660 /*
2661  * ext4_generic_delete_entry deletes a directory entry by merging it
2662  * with the previous entry
2663  */
ext4_generic_delete_entry(struct inode * dir,struct ext4_dir_entry_2 * de_del,struct buffer_head * bh,void * entry_buf,int buf_size,int csum_size)2664 int ext4_generic_delete_entry(struct inode *dir,
2665 			      struct ext4_dir_entry_2 *de_del,
2666 			      struct buffer_head *bh,
2667 			      void *entry_buf,
2668 			      int buf_size,
2669 			      int csum_size)
2670 {
2671 	struct ext4_dir_entry_2 *de, *pde;
2672 	unsigned int blocksize = dir->i_sb->s_blocksize;
2673 	int i;
2674 
2675 	i = 0;
2676 	pde = NULL;
2677 	de = entry_buf;
2678 	while (i < buf_size - csum_size) {
2679 		if (ext4_check_dir_entry(dir, NULL, de, bh,
2680 					 entry_buf, buf_size, i))
2681 			return -EFSCORRUPTED;
2682 		if (de == de_del)  {
2683 			if (pde) {
2684 				pde->rec_len = ext4_rec_len_to_disk(
2685 					ext4_rec_len_from_disk(pde->rec_len,
2686 							       blocksize) +
2687 					ext4_rec_len_from_disk(de->rec_len,
2688 							       blocksize),
2689 					blocksize);
2690 
2691 				/* wipe entire dir_entry */
2692 				memset(de, 0, ext4_rec_len_from_disk(de->rec_len,
2693 								blocksize));
2694 			} else {
2695 				/* wipe dir_entry excluding the rec_len field */
2696 				de->inode = 0;
2697 				memset(&de->name_len, 0,
2698 					ext4_rec_len_from_disk(de->rec_len,
2699 								blocksize) -
2700 					offsetof(struct ext4_dir_entry_2,
2701 								name_len));
2702 			}
2703 
2704 			inode_inc_iversion(dir);
2705 			return 0;
2706 		}
2707 		i += ext4_rec_len_from_disk(de->rec_len, blocksize);
2708 		pde = de;
2709 		de = ext4_next_entry(de, blocksize);
2710 	}
2711 	return -ENOENT;
2712 }
2713 
ext4_delete_entry(handle_t * handle,struct inode * dir,struct ext4_dir_entry_2 * de_del,struct buffer_head * bh)2714 static int ext4_delete_entry(handle_t *handle,
2715 			     struct inode *dir,
2716 			     struct ext4_dir_entry_2 *de_del,
2717 			     struct buffer_head *bh)
2718 {
2719 	int err, csum_size = 0;
2720 
2721 	if (ext4_has_inline_data(dir)) {
2722 		int has_inline_data = 1;
2723 		err = ext4_delete_inline_entry(handle, dir, de_del, bh,
2724 					       &has_inline_data);
2725 		if (has_inline_data)
2726 			return err;
2727 	}
2728 
2729 	if (ext4_has_metadata_csum(dir->i_sb))
2730 		csum_size = sizeof(struct ext4_dir_entry_tail);
2731 
2732 	BUFFER_TRACE(bh, "get_write_access");
2733 	err = ext4_journal_get_write_access(handle, dir->i_sb, bh,
2734 					    EXT4_JTR_NONE);
2735 	if (unlikely(err))
2736 		goto out;
2737 
2738 	err = ext4_generic_delete_entry(dir, de_del, bh, bh->b_data,
2739 					dir->i_sb->s_blocksize, csum_size);
2740 	if (err)
2741 		goto out;
2742 
2743 	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
2744 	err = ext4_handle_dirty_dirblock(handle, dir, bh);
2745 	if (unlikely(err))
2746 		goto out;
2747 
2748 	return 0;
2749 out:
2750 	if (err != -ENOENT)
2751 		ext4_std_error(dir->i_sb, err);
2752 	return err;
2753 }
2754 
2755 /*
2756  * Set directory link count to 1 if nlinks > EXT4_LINK_MAX, or if nlinks == 2
2757  * since this indicates that nlinks count was previously 1 to avoid overflowing
2758  * the 16-bit i_links_count field on disk.  Directories with i_nlink == 1 mean
2759  * that subdirectory link counts are not being maintained accurately.
2760  *
2761  * The caller has already checked for i_nlink overflow in case the DIR_LINK
2762  * feature is not enabled and returned -EMLINK.  The is_dx() check is a proxy
2763  * for checking S_ISDIR(inode) (since the INODE_INDEX feature will not be set
2764  * on regular files) and to avoid creating huge/slow non-HTREE directories.
2765  */
ext4_inc_count(struct inode * inode)2766 static void ext4_inc_count(struct inode *inode)
2767 {
2768 	inc_nlink(inode);
2769 	if (is_dx(inode) &&
2770 	    (inode->i_nlink > EXT4_LINK_MAX || inode->i_nlink == 2))
2771 		set_nlink(inode, 1);
2772 }
2773 
2774 /*
2775  * If a directory had nlink == 1, then we should let it be 1. This indicates
2776  * directory has >EXT4_LINK_MAX subdirs.
2777  */
ext4_dec_count(struct inode * inode)2778 static void ext4_dec_count(struct inode *inode)
2779 {
2780 	if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
2781 		drop_nlink(inode);
2782 }
2783 
2784 
2785 /*
2786  * Add non-directory inode to a directory. On success, the inode reference is
2787  * consumed by dentry is instantiation. This is also indicated by clearing of
2788  * *inodep pointer. On failure, the caller is responsible for dropping the
2789  * inode reference in the safe context.
2790  */
ext4_add_nondir(handle_t * handle,struct dentry * dentry,struct inode ** inodep)2791 static int ext4_add_nondir(handle_t *handle,
2792 		struct dentry *dentry, struct inode **inodep)
2793 {
2794 	struct inode *dir = d_inode(dentry->d_parent);
2795 	struct inode *inode = *inodep;
2796 	int err = ext4_add_entry(handle, dentry, inode);
2797 	if (!err) {
2798 		err = ext4_mark_inode_dirty(handle, inode);
2799 		if (IS_DIRSYNC(dir))
2800 			ext4_handle_sync(handle);
2801 		d_instantiate_new(dentry, inode);
2802 		*inodep = NULL;
2803 		return err;
2804 	}
2805 	drop_nlink(inode);
2806 	ext4_mark_inode_dirty(handle, inode);
2807 	ext4_orphan_add(handle, inode);
2808 	unlock_new_inode(inode);
2809 	return err;
2810 }
2811 
2812 /*
2813  * By the time this is called, we already have created
2814  * the directory cache entry for the new file, but it
2815  * is so far negative - it has no inode.
2816  *
2817  * If the create succeeds, we fill in the inode information
2818  * with d_instantiate().
2819  */
ext4_create(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode,bool excl)2820 static int ext4_create(struct mnt_idmap *idmap, struct inode *dir,
2821 		       struct dentry *dentry, umode_t mode, bool excl)
2822 {
2823 	handle_t *handle;
2824 	struct inode *inode;
2825 	int err, credits, retries = 0;
2826 
2827 	err = dquot_initialize(dir);
2828 	if (err)
2829 		return err;
2830 
2831 	credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2832 		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2833 retry:
2834 	inode = ext4_new_inode_start_handle(idmap, dir, mode, &dentry->d_name,
2835 					    0, NULL, EXT4_HT_DIR, credits);
2836 	handle = ext4_journal_current_handle();
2837 	err = PTR_ERR(inode);
2838 	if (!IS_ERR(inode)) {
2839 		inode->i_op = &ext4_file_inode_operations;
2840 		inode->i_fop = &ext4_file_operations;
2841 		ext4_set_aops(inode);
2842 		err = ext4_add_nondir(handle, dentry, &inode);
2843 		if (!err)
2844 			ext4_fc_track_create(handle, dentry);
2845 	}
2846 	if (handle)
2847 		ext4_journal_stop(handle);
2848 	if (!IS_ERR_OR_NULL(inode))
2849 		iput(inode);
2850 	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2851 		goto retry;
2852 	return err;
2853 }
2854 
ext4_mknod(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode,dev_t rdev)2855 static int ext4_mknod(struct mnt_idmap *idmap, struct inode *dir,
2856 		      struct dentry *dentry, umode_t mode, dev_t rdev)
2857 {
2858 	handle_t *handle;
2859 	struct inode *inode;
2860 	int err, credits, retries = 0;
2861 
2862 	err = dquot_initialize(dir);
2863 	if (err)
2864 		return err;
2865 
2866 	credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2867 		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2868 retry:
2869 	inode = ext4_new_inode_start_handle(idmap, dir, mode, &dentry->d_name,
2870 					    0, NULL, EXT4_HT_DIR, credits);
2871 	handle = ext4_journal_current_handle();
2872 	err = PTR_ERR(inode);
2873 	if (!IS_ERR(inode)) {
2874 		init_special_inode(inode, inode->i_mode, rdev);
2875 		inode->i_op = &ext4_special_inode_operations;
2876 		err = ext4_add_nondir(handle, dentry, &inode);
2877 		if (!err)
2878 			ext4_fc_track_create(handle, dentry);
2879 	}
2880 	if (handle)
2881 		ext4_journal_stop(handle);
2882 	if (!IS_ERR_OR_NULL(inode))
2883 		iput(inode);
2884 	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2885 		goto retry;
2886 	return err;
2887 }
2888 
ext4_tmpfile(struct mnt_idmap * idmap,struct inode * dir,struct file * file,umode_t mode)2889 static int ext4_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
2890 			struct file *file, umode_t mode)
2891 {
2892 	handle_t *handle;
2893 	struct inode *inode;
2894 	int err, retries = 0;
2895 
2896 	err = dquot_initialize(dir);
2897 	if (err)
2898 		return err;
2899 
2900 retry:
2901 	inode = ext4_new_inode_start_handle(idmap, dir, mode,
2902 					    NULL, 0, NULL,
2903 					    EXT4_HT_DIR,
2904 			EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
2905 			  4 + EXT4_XATTR_TRANS_BLOCKS);
2906 	handle = ext4_journal_current_handle();
2907 	err = PTR_ERR(inode);
2908 	if (!IS_ERR(inode)) {
2909 		inode->i_op = &ext4_file_inode_operations;
2910 		inode->i_fop = &ext4_file_operations;
2911 		ext4_set_aops(inode);
2912 		d_tmpfile(file, inode);
2913 		err = ext4_orphan_add(handle, inode);
2914 		if (err)
2915 			goto err_unlock_inode;
2916 		mark_inode_dirty(inode);
2917 		unlock_new_inode(inode);
2918 	}
2919 	if (handle)
2920 		ext4_journal_stop(handle);
2921 	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2922 		goto retry;
2923 	return finish_open_simple(file, err);
2924 err_unlock_inode:
2925 	ext4_journal_stop(handle);
2926 	unlock_new_inode(inode);
2927 	return err;
2928 }
2929 
ext4_init_dot_dotdot(struct inode * inode,struct ext4_dir_entry_2 * de,int blocksize,int csum_size,unsigned int parent_ino,int dotdot_real_len)2930 struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
2931 			  struct ext4_dir_entry_2 *de,
2932 			  int blocksize, int csum_size,
2933 			  unsigned int parent_ino, int dotdot_real_len)
2934 {
2935 	de->inode = cpu_to_le32(inode->i_ino);
2936 	de->name_len = 1;
2937 	de->rec_len = ext4_rec_len_to_disk(ext4_dir_rec_len(de->name_len, NULL),
2938 					   blocksize);
2939 	strcpy(de->name, ".");
2940 	ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2941 
2942 	de = ext4_next_entry(de, blocksize);
2943 	de->inode = cpu_to_le32(parent_ino);
2944 	de->name_len = 2;
2945 	if (!dotdot_real_len)
2946 		de->rec_len = ext4_rec_len_to_disk(blocksize -
2947 					(csum_size + ext4_dir_rec_len(1, NULL)),
2948 					blocksize);
2949 	else
2950 		de->rec_len = ext4_rec_len_to_disk(
2951 					ext4_dir_rec_len(de->name_len, NULL),
2952 					blocksize);
2953 	strcpy(de->name, "..");
2954 	ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2955 
2956 	return ext4_next_entry(de, blocksize);
2957 }
2958 
ext4_init_new_dir(handle_t * handle,struct inode * dir,struct inode * inode)2959 int ext4_init_new_dir(handle_t *handle, struct inode *dir,
2960 			     struct inode *inode)
2961 {
2962 	struct buffer_head *dir_block = NULL;
2963 	struct ext4_dir_entry_2 *de;
2964 	ext4_lblk_t block = 0;
2965 	unsigned int blocksize = dir->i_sb->s_blocksize;
2966 	int csum_size = 0;
2967 	int err;
2968 
2969 	if (ext4_has_metadata_csum(dir->i_sb))
2970 		csum_size = sizeof(struct ext4_dir_entry_tail);
2971 
2972 	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2973 		err = ext4_try_create_inline_dir(handle, dir, inode);
2974 		if (err < 0 && err != -ENOSPC)
2975 			goto out;
2976 		if (!err)
2977 			goto out;
2978 	}
2979 
2980 	inode->i_size = 0;
2981 	dir_block = ext4_append(handle, inode, &block);
2982 	if (IS_ERR(dir_block))
2983 		return PTR_ERR(dir_block);
2984 	de = (struct ext4_dir_entry_2 *)dir_block->b_data;
2985 	ext4_init_dot_dotdot(inode, de, blocksize, csum_size, dir->i_ino, 0);
2986 	set_nlink(inode, 2);
2987 	if (csum_size)
2988 		ext4_initialize_dirent_tail(dir_block, blocksize);
2989 
2990 	BUFFER_TRACE(dir_block, "call ext4_handle_dirty_metadata");
2991 	err = ext4_handle_dirty_dirblock(handle, inode, dir_block);
2992 	if (err)
2993 		goto out;
2994 	set_buffer_verified(dir_block);
2995 out:
2996 	brelse(dir_block);
2997 	return err;
2998 }
2999 
ext4_mkdir(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode)3000 static int ext4_mkdir(struct mnt_idmap *idmap, struct inode *dir,
3001 		      struct dentry *dentry, umode_t mode)
3002 {
3003 	handle_t *handle;
3004 	struct inode *inode;
3005 	int err, err2 = 0, credits, retries = 0;
3006 
3007 	if (EXT4_DIR_LINK_MAX(dir))
3008 		return -EMLINK;
3009 
3010 	err = dquot_initialize(dir);
3011 	if (err)
3012 		return err;
3013 
3014 	credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3015 		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
3016 retry:
3017 	inode = ext4_new_inode_start_handle(idmap, dir, S_IFDIR | mode,
3018 					    &dentry->d_name,
3019 					    0, NULL, EXT4_HT_DIR, credits);
3020 	handle = ext4_journal_current_handle();
3021 	err = PTR_ERR(inode);
3022 	if (IS_ERR(inode))
3023 		goto out_stop;
3024 
3025 	inode->i_op = &ext4_dir_inode_operations;
3026 	inode->i_fop = &ext4_dir_operations;
3027 	err = ext4_init_new_dir(handle, dir, inode);
3028 	if (err)
3029 		goto out_clear_inode;
3030 	err = ext4_mark_inode_dirty(handle, inode);
3031 	if (!err)
3032 		err = ext4_add_entry(handle, dentry, inode);
3033 	if (err) {
3034 out_clear_inode:
3035 		clear_nlink(inode);
3036 		ext4_orphan_add(handle, inode);
3037 		unlock_new_inode(inode);
3038 		err2 = ext4_mark_inode_dirty(handle, inode);
3039 		if (unlikely(err2))
3040 			err = err2;
3041 		ext4_journal_stop(handle);
3042 		iput(inode);
3043 		goto out_retry;
3044 	}
3045 	ext4_inc_count(dir);
3046 
3047 	ext4_update_dx_flag(dir);
3048 	err = ext4_mark_inode_dirty(handle, dir);
3049 	if (err)
3050 		goto out_clear_inode;
3051 	d_instantiate_new(dentry, inode);
3052 	ext4_fc_track_create(handle, dentry);
3053 	if (IS_DIRSYNC(dir))
3054 		ext4_handle_sync(handle);
3055 
3056 out_stop:
3057 	if (handle)
3058 		ext4_journal_stop(handle);
3059 out_retry:
3060 	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
3061 		goto retry;
3062 	return err;
3063 }
3064 
3065 /*
3066  * routine to check that the specified directory is empty (for rmdir)
3067  */
ext4_empty_dir(struct inode * inode)3068 bool ext4_empty_dir(struct inode *inode)
3069 {
3070 	unsigned int offset;
3071 	struct buffer_head *bh;
3072 	struct ext4_dir_entry_2 *de;
3073 	struct super_block *sb;
3074 
3075 	if (ext4_has_inline_data(inode)) {
3076 		int has_inline_data = 1;
3077 		int ret;
3078 
3079 		ret = empty_inline_dir(inode, &has_inline_data);
3080 		if (has_inline_data)
3081 			return ret;
3082 	}
3083 
3084 	sb = inode->i_sb;
3085 	if (inode->i_size < ext4_dir_rec_len(1, NULL) +
3086 					ext4_dir_rec_len(2, NULL)) {
3087 		EXT4_ERROR_INODE(inode, "invalid size");
3088 		return false;
3089 	}
3090 	/* The first directory block must not be a hole,
3091 	 * so treat it as DIRENT_HTREE
3092 	 */
3093 	bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE);
3094 	if (IS_ERR(bh))
3095 		return false;
3096 
3097 	de = (struct ext4_dir_entry_2 *) bh->b_data;
3098 	if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data, bh->b_size,
3099 				 0) ||
3100 	    le32_to_cpu(de->inode) != inode->i_ino || strcmp(".", de->name)) {
3101 		ext4_warning_inode(inode, "directory missing '.'");
3102 		brelse(bh);
3103 		return false;
3104 	}
3105 	offset = ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
3106 	de = ext4_next_entry(de, sb->s_blocksize);
3107 	if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data, bh->b_size,
3108 				 offset) ||
3109 	    le32_to_cpu(de->inode) == 0 || strcmp("..", de->name)) {
3110 		ext4_warning_inode(inode, "directory missing '..'");
3111 		brelse(bh);
3112 		return false;
3113 	}
3114 	offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
3115 	while (offset < inode->i_size) {
3116 		if (!(offset & (sb->s_blocksize - 1))) {
3117 			unsigned int lblock;
3118 			brelse(bh);
3119 			lblock = offset >> EXT4_BLOCK_SIZE_BITS(sb);
3120 			bh = ext4_read_dirblock(inode, lblock, EITHER);
3121 			if (bh == NULL) {
3122 				offset += sb->s_blocksize;
3123 				continue;
3124 			}
3125 			if (IS_ERR(bh))
3126 				return false;
3127 		}
3128 		de = (struct ext4_dir_entry_2 *) (bh->b_data +
3129 					(offset & (sb->s_blocksize - 1)));
3130 		if (ext4_check_dir_entry(inode, NULL, de, bh,
3131 					 bh->b_data, bh->b_size, offset) ||
3132 		    le32_to_cpu(de->inode)) {
3133 			brelse(bh);
3134 			return false;
3135 		}
3136 		offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
3137 	}
3138 	brelse(bh);
3139 	return true;
3140 }
3141 
ext4_rmdir(struct inode * dir,struct dentry * dentry)3142 static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
3143 {
3144 	int retval;
3145 	struct inode *inode;
3146 	struct buffer_head *bh;
3147 	struct ext4_dir_entry_2 *de;
3148 	handle_t *handle = NULL;
3149 
3150 	if (unlikely(ext4_forced_shutdown(dir->i_sb)))
3151 		return -EIO;
3152 
3153 	/* Initialize quotas before so that eventual writes go in
3154 	 * separate transaction */
3155 	retval = dquot_initialize(dir);
3156 	if (retval)
3157 		return retval;
3158 	retval = dquot_initialize(d_inode(dentry));
3159 	if (retval)
3160 		return retval;
3161 
3162 	retval = -ENOENT;
3163 	bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
3164 	if (IS_ERR(bh))
3165 		return PTR_ERR(bh);
3166 	if (!bh)
3167 		goto end_rmdir;
3168 
3169 	inode = d_inode(dentry);
3170 
3171 	retval = -EFSCORRUPTED;
3172 	if (le32_to_cpu(de->inode) != inode->i_ino)
3173 		goto end_rmdir;
3174 
3175 	retval = -ENOTEMPTY;
3176 	if (!ext4_empty_dir(inode))
3177 		goto end_rmdir;
3178 
3179 	handle = ext4_journal_start(dir, EXT4_HT_DIR,
3180 				    EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
3181 	if (IS_ERR(handle)) {
3182 		retval = PTR_ERR(handle);
3183 		handle = NULL;
3184 		goto end_rmdir;
3185 	}
3186 
3187 	if (IS_DIRSYNC(dir))
3188 		ext4_handle_sync(handle);
3189 
3190 	retval = ext4_delete_entry(handle, dir, de, bh);
3191 	if (retval)
3192 		goto end_rmdir;
3193 	if (!EXT4_DIR_LINK_EMPTY(inode))
3194 		ext4_warning_inode(inode,
3195 			     "empty directory '%.*s' has too many links (%u)",
3196 			     dentry->d_name.len, dentry->d_name.name,
3197 			     inode->i_nlink);
3198 	inode_inc_iversion(inode);
3199 	clear_nlink(inode);
3200 	/* There's no need to set i_disksize: the fact that i_nlink is
3201 	 * zero will ensure that the right thing happens during any
3202 	 * recovery. */
3203 	inode->i_size = 0;
3204 	ext4_orphan_add(handle, inode);
3205 	dir->i_mtime = inode_set_ctime_current(dir);
3206 	inode_set_ctime_current(inode);
3207 	retval = ext4_mark_inode_dirty(handle, inode);
3208 	if (retval)
3209 		goto end_rmdir;
3210 	ext4_dec_count(dir);
3211 	ext4_update_dx_flag(dir);
3212 	ext4_fc_track_unlink(handle, dentry);
3213 	retval = ext4_mark_inode_dirty(handle, dir);
3214 
3215 #if IS_ENABLED(CONFIG_UNICODE)
3216 	/* VFS negative dentries are incompatible with Encoding and
3217 	 * Case-insensitiveness. Eventually we'll want avoid
3218 	 * invalidating the dentries here, alongside with returning the
3219 	 * negative dentries at ext4_lookup(), when it is better
3220 	 * supported by the VFS for the CI case.
3221 	 */
3222 	if (IS_CASEFOLDED(dir))
3223 		d_invalidate(dentry);
3224 #endif
3225 
3226 end_rmdir:
3227 	brelse(bh);
3228 	if (handle)
3229 		ext4_journal_stop(handle);
3230 	return retval;
3231 }
3232 
__ext4_unlink(struct inode * dir,const struct qstr * d_name,struct inode * inode,struct dentry * dentry)3233 int __ext4_unlink(struct inode *dir, const struct qstr *d_name,
3234 		  struct inode *inode,
3235 		  struct dentry *dentry /* NULL during fast_commit recovery */)
3236 {
3237 	int retval = -ENOENT;
3238 	struct buffer_head *bh;
3239 	struct ext4_dir_entry_2 *de;
3240 	handle_t *handle;
3241 	int skip_remove_dentry = 0;
3242 
3243 	/*
3244 	 * Keep this outside the transaction; it may have to set up the
3245 	 * directory's encryption key, which isn't GFP_NOFS-safe.
3246 	 */
3247 	bh = ext4_find_entry(dir, d_name, &de, NULL);
3248 	if (IS_ERR(bh))
3249 		return PTR_ERR(bh);
3250 
3251 	if (!bh)
3252 		return -ENOENT;
3253 
3254 	if (le32_to_cpu(de->inode) != inode->i_ino) {
3255 		/*
3256 		 * It's okay if we find dont find dentry which matches
3257 		 * the inode. That's because it might have gotten
3258 		 * renamed to a different inode number
3259 		 */
3260 		if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
3261 			skip_remove_dentry = 1;
3262 		else
3263 			goto out_bh;
3264 	}
3265 
3266 	handle = ext4_journal_start(dir, EXT4_HT_DIR,
3267 				    EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
3268 	if (IS_ERR(handle)) {
3269 		retval = PTR_ERR(handle);
3270 		goto out_bh;
3271 	}
3272 
3273 	if (IS_DIRSYNC(dir))
3274 		ext4_handle_sync(handle);
3275 
3276 	if (!skip_remove_dentry) {
3277 		retval = ext4_delete_entry(handle, dir, de, bh);
3278 		if (retval)
3279 			goto out_handle;
3280 		dir->i_mtime = inode_set_ctime_current(dir);
3281 		ext4_update_dx_flag(dir);
3282 		retval = ext4_mark_inode_dirty(handle, dir);
3283 		if (retval)
3284 			goto out_handle;
3285 	} else {
3286 		retval = 0;
3287 	}
3288 	if (inode->i_nlink == 0)
3289 		ext4_warning_inode(inode, "Deleting file '%.*s' with no links",
3290 				   d_name->len, d_name->name);
3291 	else
3292 		drop_nlink(inode);
3293 	if (!inode->i_nlink)
3294 		ext4_orphan_add(handle, inode);
3295 	inode_set_ctime_current(inode);
3296 	retval = ext4_mark_inode_dirty(handle, inode);
3297 	if (dentry && !retval)
3298 		ext4_fc_track_unlink(handle, dentry);
3299 out_handle:
3300 	ext4_journal_stop(handle);
3301 out_bh:
3302 	brelse(bh);
3303 	return retval;
3304 }
3305 
ext4_unlink(struct inode * dir,struct dentry * dentry)3306 static int ext4_unlink(struct inode *dir, struct dentry *dentry)
3307 {
3308 	int retval;
3309 
3310 	if (unlikely(ext4_forced_shutdown(dir->i_sb)))
3311 		return -EIO;
3312 
3313 	trace_ext4_unlink_enter(dir, dentry);
3314 	/*
3315 	 * Initialize quotas before so that eventual writes go
3316 	 * in separate transaction
3317 	 */
3318 	retval = dquot_initialize(dir);
3319 	if (retval)
3320 		goto out_trace;
3321 	retval = dquot_initialize(d_inode(dentry));
3322 	if (retval)
3323 		goto out_trace;
3324 
3325 	retval = __ext4_unlink(dir, &dentry->d_name, d_inode(dentry), dentry);
3326 #if IS_ENABLED(CONFIG_UNICODE)
3327 	/* VFS negative dentries are incompatible with Encoding and
3328 	 * Case-insensitiveness. Eventually we'll want avoid
3329 	 * invalidating the dentries here, alongside with returning the
3330 	 * negative dentries at ext4_lookup(), when it is  better
3331 	 * supported by the VFS for the CI case.
3332 	 */
3333 	if (IS_CASEFOLDED(dir))
3334 		d_invalidate(dentry);
3335 #endif
3336 
3337 out_trace:
3338 	trace_ext4_unlink_exit(dentry, retval);
3339 	return retval;
3340 }
3341 
ext4_init_symlink_block(handle_t * handle,struct inode * inode,struct fscrypt_str * disk_link)3342 static int ext4_init_symlink_block(handle_t *handle, struct inode *inode,
3343 				   struct fscrypt_str *disk_link)
3344 {
3345 	struct buffer_head *bh;
3346 	char *kaddr;
3347 	int err = 0;
3348 
3349 	bh = ext4_bread(handle, inode, 0, EXT4_GET_BLOCKS_CREATE);
3350 	if (IS_ERR(bh))
3351 		return PTR_ERR(bh);
3352 
3353 	BUFFER_TRACE(bh, "get_write_access");
3354 	err = ext4_journal_get_write_access(handle, inode->i_sb, bh, EXT4_JTR_NONE);
3355 	if (err)
3356 		goto out;
3357 
3358 	kaddr = (char *)bh->b_data;
3359 	memcpy(kaddr, disk_link->name, disk_link->len);
3360 	inode->i_size = disk_link->len - 1;
3361 	EXT4_I(inode)->i_disksize = inode->i_size;
3362 	err = ext4_handle_dirty_metadata(handle, inode, bh);
3363 out:
3364 	brelse(bh);
3365 	return err;
3366 }
3367 
ext4_symlink(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,const char * symname)3368 static int ext4_symlink(struct mnt_idmap *idmap, struct inode *dir,
3369 			struct dentry *dentry, const char *symname)
3370 {
3371 	handle_t *handle;
3372 	struct inode *inode;
3373 	int err, len = strlen(symname);
3374 	int credits;
3375 	struct fscrypt_str disk_link;
3376 	int retries = 0;
3377 
3378 	if (unlikely(ext4_forced_shutdown(dir->i_sb)))
3379 		return -EIO;
3380 
3381 	err = fscrypt_prepare_symlink(dir, symname, len, dir->i_sb->s_blocksize,
3382 				      &disk_link);
3383 	if (err)
3384 		return err;
3385 
3386 	err = dquot_initialize(dir);
3387 	if (err)
3388 		return err;
3389 
3390 	/*
3391 	 * EXT4_INDEX_EXTRA_TRANS_BLOCKS for addition of entry into the
3392 	 * directory. +3 for inode, inode bitmap, group descriptor allocation.
3393 	 * EXT4_DATA_TRANS_BLOCKS for the data block allocation and
3394 	 * modification.
3395 	 */
3396 	credits = EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3397 		  EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3;
3398 retry:
3399 	inode = ext4_new_inode_start_handle(idmap, dir, S_IFLNK|S_IRWXUGO,
3400 					    &dentry->d_name, 0, NULL,
3401 					    EXT4_HT_DIR, credits);
3402 	handle = ext4_journal_current_handle();
3403 	if (IS_ERR(inode)) {
3404 		if (handle)
3405 			ext4_journal_stop(handle);
3406 		err = PTR_ERR(inode);
3407 		goto out_retry;
3408 	}
3409 
3410 	if (IS_ENCRYPTED(inode)) {
3411 		err = fscrypt_encrypt_symlink(inode, symname, len, &disk_link);
3412 		if (err)
3413 			goto err_drop_inode;
3414 		inode->i_op = &ext4_encrypted_symlink_inode_operations;
3415 	} else {
3416 		if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3417 			inode->i_op = &ext4_symlink_inode_operations;
3418 		} else {
3419 			inode->i_op = &ext4_fast_symlink_inode_operations;
3420 			inode->i_link = (char *)&EXT4_I(inode)->i_data;
3421 		}
3422 	}
3423 
3424 	if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3425 		/* alloc symlink block and fill it */
3426 		err = ext4_init_symlink_block(handle, inode, &disk_link);
3427 		if (err)
3428 			goto err_drop_inode;
3429 	} else {
3430 		/* clear the extent format for fast symlink */
3431 		ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
3432 		memcpy((char *)&EXT4_I(inode)->i_data, disk_link.name,
3433 		       disk_link.len);
3434 		inode->i_size = disk_link.len - 1;
3435 		EXT4_I(inode)->i_disksize = inode->i_size;
3436 	}
3437 	err = ext4_add_nondir(handle, dentry, &inode);
3438 	if (handle)
3439 		ext4_journal_stop(handle);
3440 	iput(inode);
3441 	goto out_retry;
3442 
3443 err_drop_inode:
3444 	clear_nlink(inode);
3445 	ext4_mark_inode_dirty(handle, inode);
3446 	ext4_orphan_add(handle, inode);
3447 	unlock_new_inode(inode);
3448 	if (handle)
3449 		ext4_journal_stop(handle);
3450 	iput(inode);
3451 out_retry:
3452 	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
3453 		goto retry;
3454 	if (disk_link.name != (unsigned char *)symname)
3455 		kfree(disk_link.name);
3456 	return err;
3457 }
3458 
__ext4_link(struct inode * dir,struct inode * inode,struct dentry * dentry)3459 int __ext4_link(struct inode *dir, struct inode *inode, struct dentry *dentry)
3460 {
3461 	handle_t *handle;
3462 	int err, retries = 0;
3463 retry:
3464 	handle = ext4_journal_start(dir, EXT4_HT_DIR,
3465 		(EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3466 		 EXT4_INDEX_EXTRA_TRANS_BLOCKS) + 1);
3467 	if (IS_ERR(handle))
3468 		return PTR_ERR(handle);
3469 
3470 	if (IS_DIRSYNC(dir))
3471 		ext4_handle_sync(handle);
3472 
3473 	inode_set_ctime_current(inode);
3474 	ext4_inc_count(inode);
3475 	ihold(inode);
3476 
3477 	err = ext4_add_entry(handle, dentry, inode);
3478 	if (!err) {
3479 		err = ext4_mark_inode_dirty(handle, inode);
3480 		/* this can happen only for tmpfile being
3481 		 * linked the first time
3482 		 */
3483 		if (inode->i_nlink == 1)
3484 			ext4_orphan_del(handle, inode);
3485 		d_instantiate(dentry, inode);
3486 		ext4_fc_track_link(handle, dentry);
3487 	} else {
3488 		drop_nlink(inode);
3489 		iput(inode);
3490 	}
3491 	ext4_journal_stop(handle);
3492 	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
3493 		goto retry;
3494 	return err;
3495 }
3496 
ext4_link(struct dentry * old_dentry,struct inode * dir,struct dentry * dentry)3497 static int ext4_link(struct dentry *old_dentry,
3498 		     struct inode *dir, struct dentry *dentry)
3499 {
3500 	struct inode *inode = d_inode(old_dentry);
3501 	int err;
3502 
3503 	if (inode->i_nlink >= EXT4_LINK_MAX)
3504 		return -EMLINK;
3505 
3506 	err = fscrypt_prepare_link(old_dentry, dir, dentry);
3507 	if (err)
3508 		return err;
3509 
3510 	if ((ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT)) &&
3511 	    (!projid_eq(EXT4_I(dir)->i_projid,
3512 			EXT4_I(old_dentry->d_inode)->i_projid)))
3513 		return -EXDEV;
3514 
3515 	err = dquot_initialize(dir);
3516 	if (err)
3517 		return err;
3518 	return __ext4_link(dir, inode, dentry);
3519 }
3520 
3521 /*
3522  * Try to find buffer head where contains the parent block.
3523  * It should be the inode block if it is inlined or the 1st block
3524  * if it is a normal dir.
3525  */
ext4_get_first_dir_block(handle_t * handle,struct inode * inode,int * retval,struct ext4_dir_entry_2 ** parent_de,int * inlined)3526 static struct buffer_head *ext4_get_first_dir_block(handle_t *handle,
3527 					struct inode *inode,
3528 					int *retval,
3529 					struct ext4_dir_entry_2 **parent_de,
3530 					int *inlined)
3531 {
3532 	struct buffer_head *bh;
3533 
3534 	if (!ext4_has_inline_data(inode)) {
3535 		struct ext4_dir_entry_2 *de;
3536 		unsigned int offset;
3537 
3538 		/* The first directory block must not be a hole, so
3539 		 * treat it as DIRENT_HTREE
3540 		 */
3541 		bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE);
3542 		if (IS_ERR(bh)) {
3543 			*retval = PTR_ERR(bh);
3544 			return NULL;
3545 		}
3546 
3547 		de = (struct ext4_dir_entry_2 *) bh->b_data;
3548 		if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data,
3549 					 bh->b_size, 0) ||
3550 		    le32_to_cpu(de->inode) != inode->i_ino ||
3551 		    strcmp(".", de->name)) {
3552 			EXT4_ERROR_INODE(inode, "directory missing '.'");
3553 			brelse(bh);
3554 			*retval = -EFSCORRUPTED;
3555 			return NULL;
3556 		}
3557 		offset = ext4_rec_len_from_disk(de->rec_len,
3558 						inode->i_sb->s_blocksize);
3559 		de = ext4_next_entry(de, inode->i_sb->s_blocksize);
3560 		if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data,
3561 					 bh->b_size, offset) ||
3562 		    le32_to_cpu(de->inode) == 0 || strcmp("..", de->name)) {
3563 			EXT4_ERROR_INODE(inode, "directory missing '..'");
3564 			brelse(bh);
3565 			*retval = -EFSCORRUPTED;
3566 			return NULL;
3567 		}
3568 		*parent_de = de;
3569 
3570 		return bh;
3571 	}
3572 
3573 	*inlined = 1;
3574 	return ext4_get_first_inline_block(inode, parent_de, retval);
3575 }
3576 
3577 struct ext4_renament {
3578 	struct inode *dir;
3579 	struct dentry *dentry;
3580 	struct inode *inode;
3581 	bool is_dir;
3582 	int dir_nlink_delta;
3583 
3584 	/* entry for "dentry" */
3585 	struct buffer_head *bh;
3586 	struct ext4_dir_entry_2 *de;
3587 	int inlined;
3588 
3589 	/* entry for ".." in inode if it's a directory */
3590 	struct buffer_head *dir_bh;
3591 	struct ext4_dir_entry_2 *parent_de;
3592 	int dir_inlined;
3593 };
3594 
ext4_rename_dir_prepare(handle_t * handle,struct ext4_renament * ent)3595 static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent)
3596 {
3597 	int retval;
3598 
3599 	ent->dir_bh = ext4_get_first_dir_block(handle, ent->inode,
3600 					      &retval, &ent->parent_de,
3601 					      &ent->dir_inlined);
3602 	if (!ent->dir_bh)
3603 		return retval;
3604 	if (le32_to_cpu(ent->parent_de->inode) != ent->dir->i_ino)
3605 		return -EFSCORRUPTED;
3606 	BUFFER_TRACE(ent->dir_bh, "get_write_access");
3607 	return ext4_journal_get_write_access(handle, ent->dir->i_sb,
3608 					     ent->dir_bh, EXT4_JTR_NONE);
3609 }
3610 
ext4_rename_dir_finish(handle_t * handle,struct ext4_renament * ent,unsigned dir_ino)3611 static int ext4_rename_dir_finish(handle_t *handle, struct ext4_renament *ent,
3612 				  unsigned dir_ino)
3613 {
3614 	int retval;
3615 
3616 	ent->parent_de->inode = cpu_to_le32(dir_ino);
3617 	BUFFER_TRACE(ent->dir_bh, "call ext4_handle_dirty_metadata");
3618 	if (!ent->dir_inlined) {
3619 		if (is_dx(ent->inode)) {
3620 			retval = ext4_handle_dirty_dx_node(handle,
3621 							   ent->inode,
3622 							   ent->dir_bh);
3623 		} else {
3624 			retval = ext4_handle_dirty_dirblock(handle, ent->inode,
3625 							    ent->dir_bh);
3626 		}
3627 	} else {
3628 		retval = ext4_mark_inode_dirty(handle, ent->inode);
3629 	}
3630 	if (retval) {
3631 		ext4_std_error(ent->dir->i_sb, retval);
3632 		return retval;
3633 	}
3634 	return 0;
3635 }
3636 
ext4_setent(handle_t * handle,struct ext4_renament * ent,unsigned ino,unsigned file_type)3637 static int ext4_setent(handle_t *handle, struct ext4_renament *ent,
3638 		       unsigned ino, unsigned file_type)
3639 {
3640 	int retval, retval2;
3641 
3642 	BUFFER_TRACE(ent->bh, "get write access");
3643 	retval = ext4_journal_get_write_access(handle, ent->dir->i_sb, ent->bh,
3644 					       EXT4_JTR_NONE);
3645 	if (retval)
3646 		return retval;
3647 	ent->de->inode = cpu_to_le32(ino);
3648 	if (ext4_has_feature_filetype(ent->dir->i_sb))
3649 		ent->de->file_type = file_type;
3650 	inode_inc_iversion(ent->dir);
3651 	ent->dir->i_mtime = inode_set_ctime_current(ent->dir);
3652 	retval = ext4_mark_inode_dirty(handle, ent->dir);
3653 	BUFFER_TRACE(ent->bh, "call ext4_handle_dirty_metadata");
3654 	if (!ent->inlined) {
3655 		retval2 = ext4_handle_dirty_dirblock(handle, ent->dir, ent->bh);
3656 		if (unlikely(retval2)) {
3657 			ext4_std_error(ent->dir->i_sb, retval2);
3658 			return retval2;
3659 		}
3660 	}
3661 	return retval;
3662 }
3663 
ext4_resetent(handle_t * handle,struct ext4_renament * ent,unsigned ino,unsigned file_type)3664 static void ext4_resetent(handle_t *handle, struct ext4_renament *ent,
3665 			  unsigned ino, unsigned file_type)
3666 {
3667 	struct ext4_renament old = *ent;
3668 	int retval = 0;
3669 
3670 	/*
3671 	 * old->de could have moved from under us during make indexed dir,
3672 	 * so the old->de may no longer valid and need to find it again
3673 	 * before reset old inode info.
3674 	 */
3675 	old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de,
3676 				 &old.inlined);
3677 	if (IS_ERR(old.bh))
3678 		retval = PTR_ERR(old.bh);
3679 	if (!old.bh)
3680 		retval = -ENOENT;
3681 	if (retval) {
3682 		ext4_std_error(old.dir->i_sb, retval);
3683 		return;
3684 	}
3685 
3686 	ext4_setent(handle, &old, ino, file_type);
3687 	brelse(old.bh);
3688 }
3689 
ext4_find_delete_entry(handle_t * handle,struct inode * dir,const struct qstr * d_name)3690 static int ext4_find_delete_entry(handle_t *handle, struct inode *dir,
3691 				  const struct qstr *d_name)
3692 {
3693 	int retval = -ENOENT;
3694 	struct buffer_head *bh;
3695 	struct ext4_dir_entry_2 *de;
3696 
3697 	bh = ext4_find_entry(dir, d_name, &de, NULL);
3698 	if (IS_ERR(bh))
3699 		return PTR_ERR(bh);
3700 	if (bh) {
3701 		retval = ext4_delete_entry(handle, dir, de, bh);
3702 		brelse(bh);
3703 	}
3704 	return retval;
3705 }
3706 
ext4_rename_delete(handle_t * handle,struct ext4_renament * ent,int force_reread)3707 static void ext4_rename_delete(handle_t *handle, struct ext4_renament *ent,
3708 			       int force_reread)
3709 {
3710 	int retval;
3711 	/*
3712 	 * ent->de could have moved from under us during htree split, so make
3713 	 * sure that we are deleting the right entry.  We might also be pointing
3714 	 * to a stale entry in the unused part of ent->bh so just checking inum
3715 	 * and the name isn't enough.
3716 	 */
3717 	if (le32_to_cpu(ent->de->inode) != ent->inode->i_ino ||
3718 	    ent->de->name_len != ent->dentry->d_name.len ||
3719 	    strncmp(ent->de->name, ent->dentry->d_name.name,
3720 		    ent->de->name_len) ||
3721 	    force_reread) {
3722 		retval = ext4_find_delete_entry(handle, ent->dir,
3723 						&ent->dentry->d_name);
3724 	} else {
3725 		retval = ext4_delete_entry(handle, ent->dir, ent->de, ent->bh);
3726 		if (retval == -ENOENT) {
3727 			retval = ext4_find_delete_entry(handle, ent->dir,
3728 							&ent->dentry->d_name);
3729 		}
3730 	}
3731 
3732 	if (retval) {
3733 		ext4_warning_inode(ent->dir,
3734 				   "Deleting old file: nlink %d, error=%d",
3735 				   ent->dir->i_nlink, retval);
3736 	}
3737 }
3738 
ext4_update_dir_count(handle_t * handle,struct ext4_renament * ent)3739 static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
3740 {
3741 	if (ent->dir_nlink_delta) {
3742 		if (ent->dir_nlink_delta == -1)
3743 			ext4_dec_count(ent->dir);
3744 		else
3745 			ext4_inc_count(ent->dir);
3746 		ext4_mark_inode_dirty(handle, ent->dir);
3747 	}
3748 }
3749 
ext4_whiteout_for_rename(struct mnt_idmap * idmap,struct ext4_renament * ent,int credits,handle_t ** h)3750 static struct inode *ext4_whiteout_for_rename(struct mnt_idmap *idmap,
3751 					      struct ext4_renament *ent,
3752 					      int credits, handle_t **h)
3753 {
3754 	struct inode *wh;
3755 	handle_t *handle;
3756 	int retries = 0;
3757 
3758 	/*
3759 	 * for inode block, sb block, group summaries,
3760 	 * and inode bitmap
3761 	 */
3762 	credits += (EXT4_MAXQUOTAS_TRANS_BLOCKS(ent->dir->i_sb) +
3763 		    EXT4_XATTR_TRANS_BLOCKS + 4);
3764 retry:
3765 	wh = ext4_new_inode_start_handle(idmap, ent->dir,
3766 					 S_IFCHR | WHITEOUT_MODE,
3767 					 &ent->dentry->d_name, 0, NULL,
3768 					 EXT4_HT_DIR, credits);
3769 
3770 	handle = ext4_journal_current_handle();
3771 	if (IS_ERR(wh)) {
3772 		if (handle)
3773 			ext4_journal_stop(handle);
3774 		if (PTR_ERR(wh) == -ENOSPC &&
3775 		    ext4_should_retry_alloc(ent->dir->i_sb, &retries))
3776 			goto retry;
3777 	} else {
3778 		*h = handle;
3779 		init_special_inode(wh, wh->i_mode, WHITEOUT_DEV);
3780 		wh->i_op = &ext4_special_inode_operations;
3781 	}
3782 	return wh;
3783 }
3784 
3785 /*
3786  * Anybody can rename anything with this: the permission checks are left to the
3787  * higher-level routines.
3788  *
3789  * n.b.  old_{dentry,inode) refers to the source dentry/inode
3790  * while new_{dentry,inode) refers to the destination dentry/inode
3791  * This comes from rename(const char *oldpath, const char *newpath)
3792  */
ext4_rename(struct mnt_idmap * idmap,struct inode * old_dir,struct dentry * old_dentry,struct inode * new_dir,struct dentry * new_dentry,unsigned int flags)3793 static int ext4_rename(struct mnt_idmap *idmap, struct inode *old_dir,
3794 		       struct dentry *old_dentry, struct inode *new_dir,
3795 		       struct dentry *new_dentry, unsigned int flags)
3796 {
3797 	handle_t *handle = NULL;
3798 	struct ext4_renament old = {
3799 		.dir = old_dir,
3800 		.dentry = old_dentry,
3801 		.inode = d_inode(old_dentry),
3802 	};
3803 	struct ext4_renament new = {
3804 		.dir = new_dir,
3805 		.dentry = new_dentry,
3806 		.inode = d_inode(new_dentry),
3807 	};
3808 	int force_reread;
3809 	int retval;
3810 	struct inode *whiteout = NULL;
3811 	int credits;
3812 	u8 old_file_type;
3813 
3814 	if (new.inode && new.inode->i_nlink == 0) {
3815 		EXT4_ERROR_INODE(new.inode,
3816 				 "target of rename is already freed");
3817 		return -EFSCORRUPTED;
3818 	}
3819 
3820 	if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT)) &&
3821 	    (!projid_eq(EXT4_I(new_dir)->i_projid,
3822 			EXT4_I(old_dentry->d_inode)->i_projid)))
3823 		return -EXDEV;
3824 
3825 	retval = dquot_initialize(old.dir);
3826 	if (retval)
3827 		return retval;
3828 	retval = dquot_initialize(old.inode);
3829 	if (retval)
3830 		return retval;
3831 	retval = dquot_initialize(new.dir);
3832 	if (retval)
3833 		return retval;
3834 
3835 	/* Initialize quotas before so that eventual writes go
3836 	 * in separate transaction */
3837 	if (new.inode) {
3838 		retval = dquot_initialize(new.inode);
3839 		if (retval)
3840 			return retval;
3841 	}
3842 
3843 	old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de,
3844 				 &old.inlined);
3845 	if (IS_ERR(old.bh))
3846 		return PTR_ERR(old.bh);
3847 
3848 	/*
3849 	 *  Check for inode number is _not_ due to possible IO errors.
3850 	 *  We might rmdir the source, keep it as pwd of some process
3851 	 *  and merrily kill the link to whatever was created under the
3852 	 *  same name. Goodbye sticky bit ;-<
3853 	 */
3854 	retval = -ENOENT;
3855 	if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3856 		goto release_bh;
3857 
3858 	new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3859 				 &new.de, &new.inlined);
3860 	if (IS_ERR(new.bh)) {
3861 		retval = PTR_ERR(new.bh);
3862 		new.bh = NULL;
3863 		goto release_bh;
3864 	}
3865 	if (new.bh) {
3866 		if (!new.inode) {
3867 			brelse(new.bh);
3868 			new.bh = NULL;
3869 		}
3870 	}
3871 	if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC))
3872 		ext4_alloc_da_blocks(old.inode);
3873 
3874 	credits = (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3875 		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2);
3876 	if (!(flags & RENAME_WHITEOUT)) {
3877 		handle = ext4_journal_start(old.dir, EXT4_HT_DIR, credits);
3878 		if (IS_ERR(handle)) {
3879 			retval = PTR_ERR(handle);
3880 			goto release_bh;
3881 		}
3882 	} else {
3883 		whiteout = ext4_whiteout_for_rename(idmap, &old, credits, &handle);
3884 		if (IS_ERR(whiteout)) {
3885 			retval = PTR_ERR(whiteout);
3886 			goto release_bh;
3887 		}
3888 	}
3889 
3890 	old_file_type = old.de->file_type;
3891 	if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3892 		ext4_handle_sync(handle);
3893 
3894 	if (S_ISDIR(old.inode->i_mode)) {
3895 		if (new.inode) {
3896 			retval = -ENOTEMPTY;
3897 			if (!ext4_empty_dir(new.inode))
3898 				goto end_rename;
3899 		} else {
3900 			retval = -EMLINK;
3901 			if (new.dir != old.dir && EXT4_DIR_LINK_MAX(new.dir))
3902 				goto end_rename;
3903 		}
3904 		retval = ext4_rename_dir_prepare(handle, &old);
3905 		if (retval)
3906 			goto end_rename;
3907 	}
3908 	/*
3909 	 * If we're renaming a file within an inline_data dir and adding or
3910 	 * setting the new dirent causes a conversion from inline_data to
3911 	 * extents/blockmap, we need to force the dirent delete code to
3912 	 * re-read the directory, or else we end up trying to delete a dirent
3913 	 * from what is now the extent tree root (or a block map).
3914 	 */
3915 	force_reread = (new.dir->i_ino == old.dir->i_ino &&
3916 			ext4_test_inode_flag(new.dir, EXT4_INODE_INLINE_DATA));
3917 
3918 	if (whiteout) {
3919 		/*
3920 		 * Do this before adding a new entry, so the old entry is sure
3921 		 * to be still pointing to the valid old entry.
3922 		 */
3923 		retval = ext4_setent(handle, &old, whiteout->i_ino,
3924 				     EXT4_FT_CHRDEV);
3925 		if (retval)
3926 			goto end_rename;
3927 		retval = ext4_mark_inode_dirty(handle, whiteout);
3928 		if (unlikely(retval))
3929 			goto end_rename;
3930 
3931 	}
3932 	if (!new.bh) {
3933 		retval = ext4_add_entry(handle, new.dentry, old.inode);
3934 		if (retval)
3935 			goto end_rename;
3936 	} else {
3937 		retval = ext4_setent(handle, &new,
3938 				     old.inode->i_ino, old_file_type);
3939 		if (retval)
3940 			goto end_rename;
3941 	}
3942 	if (force_reread)
3943 		force_reread = !ext4_test_inode_flag(new.dir,
3944 						     EXT4_INODE_INLINE_DATA);
3945 
3946 	/*
3947 	 * Like most other Unix systems, set the ctime for inodes on a
3948 	 * rename.
3949 	 */
3950 	inode_set_ctime_current(old.inode);
3951 	retval = ext4_mark_inode_dirty(handle, old.inode);
3952 	if (unlikely(retval))
3953 		goto end_rename;
3954 
3955 	if (!whiteout) {
3956 		/*
3957 		 * ok, that's it
3958 		 */
3959 		ext4_rename_delete(handle, &old, force_reread);
3960 	}
3961 
3962 	if (new.inode) {
3963 		ext4_dec_count(new.inode);
3964 		inode_set_ctime_current(new.inode);
3965 	}
3966 	old.dir->i_mtime = inode_set_ctime_current(old.dir);
3967 	ext4_update_dx_flag(old.dir);
3968 	if (old.dir_bh) {
3969 		retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
3970 		if (retval)
3971 			goto end_rename;
3972 
3973 		ext4_dec_count(old.dir);
3974 		if (new.inode) {
3975 			/* checked ext4_empty_dir above, can't have another
3976 			 * parent, ext4_dec_count() won't work for many-linked
3977 			 * dirs */
3978 			clear_nlink(new.inode);
3979 		} else {
3980 			ext4_inc_count(new.dir);
3981 			ext4_update_dx_flag(new.dir);
3982 			retval = ext4_mark_inode_dirty(handle, new.dir);
3983 			if (unlikely(retval))
3984 				goto end_rename;
3985 		}
3986 	}
3987 	retval = ext4_mark_inode_dirty(handle, old.dir);
3988 	if (unlikely(retval))
3989 		goto end_rename;
3990 
3991 	if (S_ISDIR(old.inode->i_mode)) {
3992 		/*
3993 		 * We disable fast commits here that's because the
3994 		 * replay code is not yet capable of changing dot dot
3995 		 * dirents in directories.
3996 		 */
3997 		ext4_fc_mark_ineligible(old.inode->i_sb,
3998 			EXT4_FC_REASON_RENAME_DIR, handle);
3999 	} else {
4000 		struct super_block *sb = old.inode->i_sb;
4001 
4002 		if (new.inode)
4003 			ext4_fc_track_unlink(handle, new.dentry);
4004 		if (test_opt2(sb, JOURNAL_FAST_COMMIT) &&
4005 		    !(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY) &&
4006 		    !(ext4_test_mount_flag(sb, EXT4_MF_FC_INELIGIBLE))) {
4007 			__ext4_fc_track_link(handle, old.inode, new.dentry);
4008 			__ext4_fc_track_unlink(handle, old.inode, old.dentry);
4009 			if (whiteout)
4010 				__ext4_fc_track_create(handle, whiteout,
4011 						       old.dentry);
4012 		}
4013 	}
4014 
4015 	if (new.inode) {
4016 		retval = ext4_mark_inode_dirty(handle, new.inode);
4017 		if (unlikely(retval))
4018 			goto end_rename;
4019 		if (!new.inode->i_nlink)
4020 			ext4_orphan_add(handle, new.inode);
4021 	}
4022 	retval = 0;
4023 
4024 end_rename:
4025 	if (whiteout) {
4026 		if (retval) {
4027 			ext4_resetent(handle, &old,
4028 				      old.inode->i_ino, old_file_type);
4029 			drop_nlink(whiteout);
4030 			ext4_mark_inode_dirty(handle, whiteout);
4031 			ext4_orphan_add(handle, whiteout);
4032 		}
4033 		unlock_new_inode(whiteout);
4034 		ext4_journal_stop(handle);
4035 		iput(whiteout);
4036 	} else {
4037 		ext4_journal_stop(handle);
4038 	}
4039 release_bh:
4040 	brelse(old.dir_bh);
4041 	brelse(old.bh);
4042 	brelse(new.bh);
4043 
4044 	return retval;
4045 }
4046 
ext4_cross_rename(struct inode * old_dir,struct dentry * old_dentry,struct inode * new_dir,struct dentry * new_dentry)4047 static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
4048 			     struct inode *new_dir, struct dentry *new_dentry)
4049 {
4050 	handle_t *handle = NULL;
4051 	struct ext4_renament old = {
4052 		.dir = old_dir,
4053 		.dentry = old_dentry,
4054 		.inode = d_inode(old_dentry),
4055 	};
4056 	struct ext4_renament new = {
4057 		.dir = new_dir,
4058 		.dentry = new_dentry,
4059 		.inode = d_inode(new_dentry),
4060 	};
4061 	u8 new_file_type;
4062 	int retval;
4063 
4064 	if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT) &&
4065 	     !projid_eq(EXT4_I(new_dir)->i_projid,
4066 			EXT4_I(old_dentry->d_inode)->i_projid)) ||
4067 	    (ext4_test_inode_flag(old_dir, EXT4_INODE_PROJINHERIT) &&
4068 	     !projid_eq(EXT4_I(old_dir)->i_projid,
4069 			EXT4_I(new_dentry->d_inode)->i_projid)))
4070 		return -EXDEV;
4071 
4072 	retval = dquot_initialize(old.dir);
4073 	if (retval)
4074 		return retval;
4075 	retval = dquot_initialize(new.dir);
4076 	if (retval)
4077 		return retval;
4078 
4079 	old.bh = ext4_find_entry(old.dir, &old.dentry->d_name,
4080 				 &old.de, &old.inlined);
4081 	if (IS_ERR(old.bh))
4082 		return PTR_ERR(old.bh);
4083 	/*
4084 	 *  Check for inode number is _not_ due to possible IO errors.
4085 	 *  We might rmdir the source, keep it as pwd of some process
4086 	 *  and merrily kill the link to whatever was created under the
4087 	 *  same name. Goodbye sticky bit ;-<
4088 	 */
4089 	retval = -ENOENT;
4090 	if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
4091 		goto end_rename;
4092 
4093 	new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
4094 				 &new.de, &new.inlined);
4095 	if (IS_ERR(new.bh)) {
4096 		retval = PTR_ERR(new.bh);
4097 		new.bh = NULL;
4098 		goto end_rename;
4099 	}
4100 
4101 	/* RENAME_EXCHANGE case: old *and* new must both exist */
4102 	if (!new.bh || le32_to_cpu(new.de->inode) != new.inode->i_ino)
4103 		goto end_rename;
4104 
4105 	handle = ext4_journal_start(old.dir, EXT4_HT_DIR,
4106 		(2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
4107 		 2 * EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));
4108 	if (IS_ERR(handle)) {
4109 		retval = PTR_ERR(handle);
4110 		handle = NULL;
4111 		goto end_rename;
4112 	}
4113 
4114 	if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
4115 		ext4_handle_sync(handle);
4116 
4117 	if (S_ISDIR(old.inode->i_mode)) {
4118 		old.is_dir = true;
4119 		retval = ext4_rename_dir_prepare(handle, &old);
4120 		if (retval)
4121 			goto end_rename;
4122 	}
4123 	if (S_ISDIR(new.inode->i_mode)) {
4124 		new.is_dir = true;
4125 		retval = ext4_rename_dir_prepare(handle, &new);
4126 		if (retval)
4127 			goto end_rename;
4128 	}
4129 
4130 	/*
4131 	 * Other than the special case of overwriting a directory, parents'
4132 	 * nlink only needs to be modified if this is a cross directory rename.
4133 	 */
4134 	if (old.dir != new.dir && old.is_dir != new.is_dir) {
4135 		old.dir_nlink_delta = old.is_dir ? -1 : 1;
4136 		new.dir_nlink_delta = -old.dir_nlink_delta;
4137 		retval = -EMLINK;
4138 		if ((old.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(old.dir)) ||
4139 		    (new.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(new.dir)))
4140 			goto end_rename;
4141 	}
4142 
4143 	new_file_type = new.de->file_type;
4144 	retval = ext4_setent(handle, &new, old.inode->i_ino, old.de->file_type);
4145 	if (retval)
4146 		goto end_rename;
4147 
4148 	retval = ext4_setent(handle, &old, new.inode->i_ino, new_file_type);
4149 	if (retval)
4150 		goto end_rename;
4151 
4152 	/*
4153 	 * Like most other Unix systems, set the ctime for inodes on a
4154 	 * rename.
4155 	 */
4156 	inode_set_ctime_current(old.inode);
4157 	inode_set_ctime_current(new.inode);
4158 	retval = ext4_mark_inode_dirty(handle, old.inode);
4159 	if (unlikely(retval))
4160 		goto end_rename;
4161 	retval = ext4_mark_inode_dirty(handle, new.inode);
4162 	if (unlikely(retval))
4163 		goto end_rename;
4164 	ext4_fc_mark_ineligible(new.inode->i_sb,
4165 				EXT4_FC_REASON_CROSS_RENAME, handle);
4166 	if (old.dir_bh) {
4167 		retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
4168 		if (retval)
4169 			goto end_rename;
4170 	}
4171 	if (new.dir_bh) {
4172 		retval = ext4_rename_dir_finish(handle, &new, old.dir->i_ino);
4173 		if (retval)
4174 			goto end_rename;
4175 	}
4176 	ext4_update_dir_count(handle, &old);
4177 	ext4_update_dir_count(handle, &new);
4178 	retval = 0;
4179 
4180 end_rename:
4181 	brelse(old.dir_bh);
4182 	brelse(new.dir_bh);
4183 	brelse(old.bh);
4184 	brelse(new.bh);
4185 	if (handle)
4186 		ext4_journal_stop(handle);
4187 	return retval;
4188 }
4189 
ext4_rename2(struct mnt_idmap * idmap,struct inode * old_dir,struct dentry * old_dentry,struct inode * new_dir,struct dentry * new_dentry,unsigned int flags)4190 static int ext4_rename2(struct mnt_idmap *idmap,
4191 			struct inode *old_dir, struct dentry *old_dentry,
4192 			struct inode *new_dir, struct dentry *new_dentry,
4193 			unsigned int flags)
4194 {
4195 	int err;
4196 
4197 	if (unlikely(ext4_forced_shutdown(old_dir->i_sb)))
4198 		return -EIO;
4199 
4200 	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
4201 		return -EINVAL;
4202 
4203 	err = fscrypt_prepare_rename(old_dir, old_dentry, new_dir, new_dentry,
4204 				     flags);
4205 	if (err)
4206 		return err;
4207 
4208 	if (flags & RENAME_EXCHANGE) {
4209 		return ext4_cross_rename(old_dir, old_dentry,
4210 					 new_dir, new_dentry);
4211 	}
4212 
4213 	return ext4_rename(idmap, old_dir, old_dentry, new_dir, new_dentry, flags);
4214 }
4215 
4216 /*
4217  * directories can handle most operations...
4218  */
4219 const struct inode_operations ext4_dir_inode_operations = {
4220 	.create		= ext4_create,
4221 	.lookup		= ext4_lookup,
4222 	.link		= ext4_link,
4223 	.unlink		= ext4_unlink,
4224 	.symlink	= ext4_symlink,
4225 	.mkdir		= ext4_mkdir,
4226 	.rmdir		= ext4_rmdir,
4227 	.mknod		= ext4_mknod,
4228 	.tmpfile	= ext4_tmpfile,
4229 	.rename		= ext4_rename2,
4230 	.setattr	= ext4_setattr,
4231 	.getattr	= ext4_getattr,
4232 	.listxattr	= ext4_listxattr,
4233 	.get_inode_acl	= ext4_get_acl,
4234 	.set_acl	= ext4_set_acl,
4235 	.fiemap         = ext4_fiemap,
4236 	.fileattr_get	= ext4_fileattr_get,
4237 	.fileattr_set	= ext4_fileattr_set,
4238 };
4239 
4240 const struct inode_operations ext4_special_inode_operations = {
4241 	.setattr	= ext4_setattr,
4242 	.getattr	= ext4_getattr,
4243 	.listxattr	= ext4_listxattr,
4244 	.get_inode_acl	= ext4_get_acl,
4245 	.set_acl	= ext4_set_acl,
4246 };
4247