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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 	BUFFER_TRACE(bh, "get_write_access");
89 	err = ext4_journal_get_write_access(handle, bh);
90 	if (err) {
91 		brelse(bh);
92 		ext4_std_error(inode->i_sb, err);
93 		return ERR_PTR(err);
94 	}
95 	return bh;
96 }
97 
98 static int ext4_dx_csum_verify(struct inode *inode,
99 			       struct ext4_dir_entry *dirent);
100 
101 /*
102  * Hints to ext4_read_dirblock regarding whether we expect a directory
103  * block being read to be an index block, or a block containing
104  * directory entries (and if the latter, whether it was found via a
105  * logical block in an htree index block).  This is used to control
106  * what sort of sanity checkinig ext4_read_dirblock() will do on the
107  * directory block read from the storage device.  EITHER will means
108  * the caller doesn't know what kind of directory block will be read,
109  * so no specific verification will be done.
110  */
111 typedef enum {
112 	EITHER, INDEX, DIRENT, DIRENT_HTREE
113 } dirblock_type_t;
114 
115 #define ext4_read_dirblock(inode, block, type) \
116 	__ext4_read_dirblock((inode), (block), (type), __func__, __LINE__)
117 
__ext4_read_dirblock(struct inode * inode,ext4_lblk_t block,dirblock_type_t type,const char * func,unsigned int line)118 static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
119 						ext4_lblk_t block,
120 						dirblock_type_t type,
121 						const char *func,
122 						unsigned int line)
123 {
124 	struct buffer_head *bh;
125 	struct ext4_dir_entry *dirent;
126 	int is_dx_block = 0;
127 
128 	bh = ext4_bread(NULL, inode, block, 0);
129 	if (IS_ERR(bh)) {
130 		__ext4_warning(inode->i_sb, func, line,
131 			       "inode #%lu: lblock %lu: comm %s: "
132 			       "error %ld reading directory block",
133 			       inode->i_ino, (unsigned long)block,
134 			       current->comm, PTR_ERR(bh));
135 
136 		return bh;
137 	}
138 	if (!bh && (type == INDEX || type == DIRENT_HTREE)) {
139 		ext4_error_inode(inode, func, line, block,
140 				 "Directory hole found for htree %s block",
141 				 (type == INDEX) ? "index" : "leaf");
142 		return ERR_PTR(-EFSCORRUPTED);
143 	}
144 	if (!bh)
145 		return NULL;
146 	dirent = (struct ext4_dir_entry *) bh->b_data;
147 	/* Determine whether or not we have an index block */
148 	if (is_dx(inode)) {
149 		if (block == 0)
150 			is_dx_block = 1;
151 		else if (ext4_rec_len_from_disk(dirent->rec_len,
152 						inode->i_sb->s_blocksize) ==
153 			 inode->i_sb->s_blocksize)
154 			is_dx_block = 1;
155 	}
156 	if (!is_dx_block && type == INDEX) {
157 		ext4_error_inode(inode, func, line, block,
158 		       "directory leaf block found instead of index block");
159 		brelse(bh);
160 		return ERR_PTR(-EFSCORRUPTED);
161 	}
162 	if (!ext4_has_metadata_csum(inode->i_sb) ||
163 	    buffer_verified(bh))
164 		return bh;
165 
166 	/*
167 	 * An empty leaf block can get mistaken for a index block; for
168 	 * this reason, we can only check the index checksum when the
169 	 * caller is sure it should be an index block.
170 	 */
171 	if (is_dx_block && type == INDEX) {
172 		if (ext4_dx_csum_verify(inode, dirent))
173 			set_buffer_verified(bh);
174 		else {
175 			ext4_error_inode(inode, func, line, block,
176 					 "Directory index failed checksum");
177 			brelse(bh);
178 			return ERR_PTR(-EFSBADCRC);
179 		}
180 	}
181 	if (!is_dx_block) {
182 		if (ext4_dirblock_csum_verify(inode, bh))
183 			set_buffer_verified(bh);
184 		else {
185 			ext4_error_inode(inode, func, line, block,
186 					 "Directory block failed checksum");
187 			brelse(bh);
188 			return ERR_PTR(-EFSBADCRC);
189 		}
190 	}
191 	return bh;
192 }
193 
194 #ifndef assert
195 #define assert(test) J_ASSERT(test)
196 #endif
197 
198 #ifdef DX_DEBUG
199 #define dxtrace(command) command
200 #else
201 #define dxtrace(command)
202 #endif
203 
204 struct fake_dirent
205 {
206 	__le32 inode;
207 	__le16 rec_len;
208 	u8 name_len;
209 	u8 file_type;
210 };
211 
212 struct dx_countlimit
213 {
214 	__le16 limit;
215 	__le16 count;
216 };
217 
218 struct dx_entry
219 {
220 	__le32 hash;
221 	__le32 block;
222 };
223 
224 /*
225  * dx_root_info is laid out so that if it should somehow get overlaid by a
226  * dirent the two low bits of the hash version will be zero.  Therefore, the
227  * hash version mod 4 should never be 0.  Sincerely, the paranoia department.
228  */
229 
230 struct dx_root
231 {
232 	struct fake_dirent dot;
233 	char dot_name[4];
234 	struct fake_dirent dotdot;
235 	char dotdot_name[4];
236 	struct dx_root_info
237 	{
238 		__le32 reserved_zero;
239 		u8 hash_version;
240 		u8 info_length; /* 8 */
241 		u8 indirect_levels;
242 		u8 unused_flags;
243 	}
244 	info;
245 	struct dx_entry	entries[0];
246 };
247 
248 struct dx_node
249 {
250 	struct fake_dirent fake;
251 	struct dx_entry	entries[0];
252 };
253 
254 
255 struct dx_frame
256 {
257 	struct buffer_head *bh;
258 	struct dx_entry *entries;
259 	struct dx_entry *at;
260 };
261 
262 struct dx_map_entry
263 {
264 	u32 hash;
265 	u16 offs;
266 	u16 size;
267 };
268 
269 /*
270  * This goes at the end of each htree block.
271  */
272 struct dx_tail {
273 	u32 dt_reserved;
274 	__le32 dt_checksum;	/* crc32c(uuid+inum+dirblock) */
275 };
276 
277 static inline ext4_lblk_t dx_get_block(struct dx_entry *entry);
278 static void dx_set_block(struct dx_entry *entry, ext4_lblk_t value);
279 static inline unsigned dx_get_hash(struct dx_entry *entry);
280 static void dx_set_hash(struct dx_entry *entry, unsigned value);
281 static unsigned dx_get_count(struct dx_entry *entries);
282 static unsigned dx_get_limit(struct dx_entry *entries);
283 static void dx_set_count(struct dx_entry *entries, unsigned value);
284 static void dx_set_limit(struct dx_entry *entries, unsigned value);
285 static unsigned dx_root_limit(struct inode *dir, unsigned infosize);
286 static unsigned dx_node_limit(struct inode *dir);
287 static struct dx_frame *dx_probe(struct ext4_filename *fname,
288 				 struct inode *dir,
289 				 struct dx_hash_info *hinfo,
290 				 struct dx_frame *frame);
291 static void dx_release(struct dx_frame *frames);
292 static int dx_make_map(struct inode *dir, struct buffer_head *bh,
293 		       struct dx_hash_info *hinfo,
294 		       struct dx_map_entry *map_tail);
295 static void dx_sort_map(struct dx_map_entry *map, unsigned count);
296 static struct ext4_dir_entry_2 *dx_move_dirents(struct inode *dir, char *from,
297 					char *to, struct dx_map_entry *offsets,
298 					int count, unsigned int blocksize);
299 static struct ext4_dir_entry_2 *dx_pack_dirents(struct inode *dir, char *base,
300 						unsigned int blocksize);
301 static void dx_insert_block(struct dx_frame *frame,
302 					u32 hash, ext4_lblk_t block);
303 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
304 				 struct dx_frame *frame,
305 				 struct dx_frame *frames,
306 				 __u32 *start_hash);
307 static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
308 		struct ext4_filename *fname,
309 		struct ext4_dir_entry_2 **res_dir);
310 static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
311 			     struct inode *dir, struct inode *inode);
312 
313 /* checksumming functions */
ext4_initialize_dirent_tail(struct buffer_head * bh,unsigned int blocksize)314 void ext4_initialize_dirent_tail(struct buffer_head *bh,
315 				 unsigned int blocksize)
316 {
317 	struct ext4_dir_entry_tail *t = EXT4_DIRENT_TAIL(bh->b_data, blocksize);
318 
319 	memset(t, 0, sizeof(struct ext4_dir_entry_tail));
320 	t->det_rec_len = ext4_rec_len_to_disk(
321 			sizeof(struct ext4_dir_entry_tail), blocksize);
322 	t->det_reserved_ft = EXT4_FT_DIR_CSUM;
323 }
324 
325 /* Walk through a dirent block to find a checksum "dirent" at the tail */
get_dirent_tail(struct inode * inode,struct buffer_head * bh)326 static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,
327 						   struct buffer_head *bh)
328 {
329 	struct ext4_dir_entry_tail *t;
330 	int blocksize = EXT4_BLOCK_SIZE(inode->i_sb);
331 
332 #ifdef PARANOID
333 	struct ext4_dir_entry *d, *top;
334 
335 	d = (struct ext4_dir_entry *)bh->b_data;
336 	top = (struct ext4_dir_entry *)(bh->b_data +
337 		(blocksize - sizeof(struct ext4_dir_entry_tail)));
338 	while (d < top && ext4_rec_len_from_disk(d->rec_len, blocksize))
339 		d = (struct ext4_dir_entry *)(((void *)d) +
340 		    ext4_rec_len_from_disk(d->rec_len, blocksize));
341 
342 	if (d != top)
343 		return NULL;
344 
345 	t = (struct ext4_dir_entry_tail *)d;
346 #else
347 	t = EXT4_DIRENT_TAIL(bh->b_data, EXT4_BLOCK_SIZE(inode->i_sb));
348 #endif
349 
350 	if (t->det_reserved_zero1 ||
351 	    (ext4_rec_len_from_disk(t->det_rec_len, blocksize) !=
352 	     sizeof(struct ext4_dir_entry_tail)) ||
353 	    t->det_reserved_zero2 ||
354 	    t->det_reserved_ft != EXT4_FT_DIR_CSUM)
355 		return NULL;
356 
357 	return t;
358 }
359 
ext4_dirblock_csum(struct inode * inode,void * dirent,int size)360 static __le32 ext4_dirblock_csum(struct inode *inode, void *dirent, int size)
361 {
362 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
363 	struct ext4_inode_info *ei = EXT4_I(inode);
364 	__u32 csum;
365 
366 	csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
367 	return cpu_to_le32(csum);
368 }
369 
370 #define warn_no_space_for_csum(inode)					\
371 	__warn_no_space_for_csum((inode), __func__, __LINE__)
372 
__warn_no_space_for_csum(struct inode * inode,const char * func,unsigned int line)373 static void __warn_no_space_for_csum(struct inode *inode, const char *func,
374 				     unsigned int line)
375 {
376 	__ext4_warning_inode(inode, func, line,
377 		"No space for directory leaf checksum. Please run e2fsck -D.");
378 }
379 
ext4_dirblock_csum_verify(struct inode * inode,struct buffer_head * bh)380 int ext4_dirblock_csum_verify(struct inode *inode, struct buffer_head *bh)
381 {
382 	struct ext4_dir_entry_tail *t;
383 
384 	if (!ext4_has_metadata_csum(inode->i_sb))
385 		return 1;
386 
387 	t = get_dirent_tail(inode, bh);
388 	if (!t) {
389 		warn_no_space_for_csum(inode);
390 		return 0;
391 	}
392 
393 	if (t->det_checksum != ext4_dirblock_csum(inode, bh->b_data,
394 						  (char *)t - bh->b_data))
395 		return 0;
396 
397 	return 1;
398 }
399 
ext4_dirblock_csum_set(struct inode * inode,struct buffer_head * bh)400 static void ext4_dirblock_csum_set(struct inode *inode,
401 				 struct buffer_head *bh)
402 {
403 	struct ext4_dir_entry_tail *t;
404 
405 	if (!ext4_has_metadata_csum(inode->i_sb))
406 		return;
407 
408 	t = get_dirent_tail(inode, bh);
409 	if (!t) {
410 		warn_no_space_for_csum(inode);
411 		return;
412 	}
413 
414 	t->det_checksum = ext4_dirblock_csum(inode, bh->b_data,
415 					     (char *)t - bh->b_data);
416 }
417 
ext4_handle_dirty_dirblock(handle_t * handle,struct inode * inode,struct buffer_head * bh)418 int ext4_handle_dirty_dirblock(handle_t *handle,
419 			       struct inode *inode,
420 			       struct buffer_head *bh)
421 {
422 	ext4_dirblock_csum_set(inode, bh);
423 	return ext4_handle_dirty_metadata(handle, inode, bh);
424 }
425 
get_dx_countlimit(struct inode * inode,struct ext4_dir_entry * dirent,int * offset)426 static struct dx_countlimit *get_dx_countlimit(struct inode *inode,
427 					       struct ext4_dir_entry *dirent,
428 					       int *offset)
429 {
430 	struct ext4_dir_entry *dp;
431 	struct dx_root_info *root;
432 	int count_offset;
433 	int blocksize = EXT4_BLOCK_SIZE(inode->i_sb);
434 	unsigned int rlen = ext4_rec_len_from_disk(dirent->rec_len, blocksize);
435 
436 	if (rlen == blocksize)
437 		count_offset = 8;
438 	else if (rlen == 12) {
439 		dp = (struct ext4_dir_entry *)(((void *)dirent) + 12);
440 		if (ext4_rec_len_from_disk(dp->rec_len, blocksize) != blocksize - 12)
441 			return NULL;
442 		root = (struct dx_root_info *)(((void *)dp + 12));
443 		if (root->reserved_zero ||
444 		    root->info_length != sizeof(struct dx_root_info))
445 			return NULL;
446 		count_offset = 32;
447 	} else
448 		return NULL;
449 
450 	if (offset)
451 		*offset = count_offset;
452 	return (struct dx_countlimit *)(((void *)dirent) + count_offset);
453 }
454 
ext4_dx_csum(struct inode * inode,struct ext4_dir_entry * dirent,int count_offset,int count,struct dx_tail * t)455 static __le32 ext4_dx_csum(struct inode *inode, struct ext4_dir_entry *dirent,
456 			   int count_offset, int count, struct dx_tail *t)
457 {
458 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
459 	struct ext4_inode_info *ei = EXT4_I(inode);
460 	__u32 csum;
461 	int size;
462 	__u32 dummy_csum = 0;
463 	int offset = offsetof(struct dx_tail, dt_checksum);
464 
465 	size = count_offset + (count * sizeof(struct dx_entry));
466 	csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
467 	csum = ext4_chksum(sbi, csum, (__u8 *)t, offset);
468 	csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
469 
470 	return cpu_to_le32(csum);
471 }
472 
ext4_dx_csum_verify(struct inode * inode,struct ext4_dir_entry * dirent)473 static int ext4_dx_csum_verify(struct inode *inode,
474 			       struct ext4_dir_entry *dirent)
475 {
476 	struct dx_countlimit *c;
477 	struct dx_tail *t;
478 	int count_offset, limit, count;
479 
480 	if (!ext4_has_metadata_csum(inode->i_sb))
481 		return 1;
482 
483 	c = get_dx_countlimit(inode, dirent, &count_offset);
484 	if (!c) {
485 		EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
486 		return 0;
487 	}
488 	limit = le16_to_cpu(c->limit);
489 	count = le16_to_cpu(c->count);
490 	if (count_offset + (limit * sizeof(struct dx_entry)) >
491 	    EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
492 		warn_no_space_for_csum(inode);
493 		return 0;
494 	}
495 	t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
496 
497 	if (t->dt_checksum != ext4_dx_csum(inode, dirent, count_offset,
498 					    count, t))
499 		return 0;
500 	return 1;
501 }
502 
ext4_dx_csum_set(struct inode * inode,struct ext4_dir_entry * dirent)503 static void ext4_dx_csum_set(struct inode *inode, struct ext4_dir_entry *dirent)
504 {
505 	struct dx_countlimit *c;
506 	struct dx_tail *t;
507 	int count_offset, limit, count;
508 
509 	if (!ext4_has_metadata_csum(inode->i_sb))
510 		return;
511 
512 	c = get_dx_countlimit(inode, dirent, &count_offset);
513 	if (!c) {
514 		EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
515 		return;
516 	}
517 	limit = le16_to_cpu(c->limit);
518 	count = le16_to_cpu(c->count);
519 	if (count_offset + (limit * sizeof(struct dx_entry)) >
520 	    EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
521 		warn_no_space_for_csum(inode);
522 		return;
523 	}
524 	t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
525 
526 	t->dt_checksum = ext4_dx_csum(inode, dirent, count_offset, count, t);
527 }
528 
ext4_handle_dirty_dx_node(handle_t * handle,struct inode * inode,struct buffer_head * bh)529 static inline int ext4_handle_dirty_dx_node(handle_t *handle,
530 					    struct inode *inode,
531 					    struct buffer_head *bh)
532 {
533 	ext4_dx_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
534 	return ext4_handle_dirty_metadata(handle, inode, bh);
535 }
536 
537 /*
538  * p is at least 6 bytes before the end of page
539  */
540 static inline struct ext4_dir_entry_2 *
ext4_next_entry(struct ext4_dir_entry_2 * p,unsigned long blocksize)541 ext4_next_entry(struct ext4_dir_entry_2 *p, unsigned long blocksize)
542 {
543 	return (struct ext4_dir_entry_2 *)((char *)p +
544 		ext4_rec_len_from_disk(p->rec_len, blocksize));
545 }
546 
547 /*
548  * Future: use high four bits of block for coalesce-on-delete flags
549  * Mask them off for now.
550  */
551 
dx_get_block(struct dx_entry * entry)552 static inline ext4_lblk_t dx_get_block(struct dx_entry *entry)
553 {
554 	return le32_to_cpu(entry->block) & 0x0fffffff;
555 }
556 
dx_set_block(struct dx_entry * entry,ext4_lblk_t value)557 static inline void dx_set_block(struct dx_entry *entry, ext4_lblk_t value)
558 {
559 	entry->block = cpu_to_le32(value);
560 }
561 
dx_get_hash(struct dx_entry * entry)562 static inline unsigned dx_get_hash(struct dx_entry *entry)
563 {
564 	return le32_to_cpu(entry->hash);
565 }
566 
dx_set_hash(struct dx_entry * entry,unsigned value)567 static inline void dx_set_hash(struct dx_entry *entry, unsigned value)
568 {
569 	entry->hash = cpu_to_le32(value);
570 }
571 
dx_get_count(struct dx_entry * entries)572 static inline unsigned dx_get_count(struct dx_entry *entries)
573 {
574 	return le16_to_cpu(((struct dx_countlimit *) entries)->count);
575 }
576 
dx_get_limit(struct dx_entry * entries)577 static inline unsigned dx_get_limit(struct dx_entry *entries)
578 {
579 	return le16_to_cpu(((struct dx_countlimit *) entries)->limit);
580 }
581 
dx_set_count(struct dx_entry * entries,unsigned value)582 static inline void dx_set_count(struct dx_entry *entries, unsigned value)
583 {
584 	((struct dx_countlimit *) entries)->count = cpu_to_le16(value);
585 }
586 
dx_set_limit(struct dx_entry * entries,unsigned value)587 static inline void dx_set_limit(struct dx_entry *entries, unsigned value)
588 {
589 	((struct dx_countlimit *) entries)->limit = cpu_to_le16(value);
590 }
591 
dx_root_limit(struct inode * dir,unsigned infosize)592 static inline unsigned dx_root_limit(struct inode *dir, unsigned infosize)
593 {
594 	unsigned int entry_space = dir->i_sb->s_blocksize -
595 			ext4_dir_rec_len(1, NULL) -
596 			ext4_dir_rec_len(2, NULL) - infosize;
597 
598 	if (ext4_has_metadata_csum(dir->i_sb))
599 		entry_space -= sizeof(struct dx_tail);
600 	return entry_space / sizeof(struct dx_entry);
601 }
602 
dx_node_limit(struct inode * dir)603 static inline unsigned dx_node_limit(struct inode *dir)
604 {
605 	unsigned int entry_space = dir->i_sb->s_blocksize -
606 			ext4_dir_rec_len(0, dir);
607 
608 	if (ext4_has_metadata_csum(dir->i_sb))
609 		entry_space -= sizeof(struct dx_tail);
610 	return entry_space / sizeof(struct dx_entry);
611 }
612 
613 /*
614  * Debug
615  */
616 #ifdef DX_DEBUG
dx_show_index(char * label,struct dx_entry * entries)617 static void dx_show_index(char * label, struct dx_entry *entries)
618 {
619 	int i, n = dx_get_count (entries);
620 	printk(KERN_DEBUG "%s index", label);
621 	for (i = 0; i < n; i++) {
622 		printk(KERN_CONT " %x->%lu",
623 		       i ? dx_get_hash(entries + i) : 0,
624 		       (unsigned long)dx_get_block(entries + i));
625 	}
626 	printk(KERN_CONT "\n");
627 }
628 
629 struct stats
630 {
631 	unsigned names;
632 	unsigned space;
633 	unsigned bcount;
634 };
635 
dx_show_leaf(struct inode * dir,struct dx_hash_info * hinfo,struct ext4_dir_entry_2 * de,int size,int show_names)636 static struct stats dx_show_leaf(struct inode *dir,
637 				struct dx_hash_info *hinfo,
638 				struct ext4_dir_entry_2 *de,
639 				int size, int show_names)
640 {
641 	unsigned names = 0, space = 0;
642 	char *base = (char *) de;
643 	struct dx_hash_info h = *hinfo;
644 
645 	printk("names: ");
646 	while ((char *) de < base + size)
647 	{
648 		if (de->inode)
649 		{
650 			if (show_names)
651 			{
652 #ifdef CONFIG_FS_ENCRYPTION
653 				int len;
654 				char *name;
655 				struct fscrypt_str fname_crypto_str =
656 					FSTR_INIT(NULL, 0);
657 				int res = 0;
658 
659 				name  = de->name;
660 				len = de->name_len;
661 				if (IS_ENCRYPTED(dir))
662 					res = fscrypt_get_encryption_info(dir);
663 				if (res) {
664 					printk(KERN_WARNING "Error setting up"
665 					       " fname crypto: %d\n", res);
666 				}
667 				if (!fscrypt_has_encryption_key(dir)) {
668 					/* Directory is not encrypted */
669 					ext4fs_dirhash(dir, de->name,
670 						de->name_len, &h);
671 					printk("%*.s:(U)%x.%u ", len,
672 					       name, h.hash,
673 					       (unsigned) ((char *) de
674 							   - base));
675 				} else {
676 					struct fscrypt_str de_name =
677 						FSTR_INIT(name, len);
678 
679 					/* Directory is encrypted */
680 					res = fscrypt_fname_alloc_buffer(
681 						dir, len,
682 						&fname_crypto_str);
683 					if (res)
684 						printk(KERN_WARNING "Error "
685 							"allocating crypto "
686 							"buffer--skipping "
687 							"crypto\n");
688 					res = fscrypt_fname_disk_to_usr(dir,
689 						0, 0, &de_name,
690 						&fname_crypto_str);
691 					if (res) {
692 						printk(KERN_WARNING "Error "
693 							"converting filename "
694 							"from disk to usr"
695 							"\n");
696 						name = "??";
697 						len = 2;
698 					} else {
699 						name = fname_crypto_str.name;
700 						len = fname_crypto_str.len;
701 					}
702 					if (IS_CASEFOLDED(dir))
703 						h.hash = EXT4_DIRENT_HASH(de);
704 					else
705 						ext4fs_dirhash(dir, de->name,
706 						       de->name_len, &h);
707 					printk("%*.s:(E)%x.%u ", len, name,
708 					       h.hash, (unsigned) ((char *) de
709 								   - base));
710 					fscrypt_fname_free_buffer(
711 							&fname_crypto_str);
712 				}
713 #else
714 				int len = de->name_len;
715 				char *name = de->name;
716 				ext4fs_dirhash(dir, de->name, de->name_len, &h);
717 				printk("%*.s:%x.%u ", len, name, h.hash,
718 				       (unsigned) ((char *) de - base));
719 #endif
720 			}
721 			space += ext4_dir_rec_len(de->name_len, dir);
722 			names++;
723 		}
724 		de = ext4_next_entry(de, size);
725 	}
726 	printk(KERN_CONT "(%i)\n", names);
727 	return (struct stats) { names, space, 1 };
728 }
729 
dx_show_entries(struct dx_hash_info * hinfo,struct inode * dir,struct dx_entry * entries,int levels)730 struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir,
731 			     struct dx_entry *entries, int levels)
732 {
733 	unsigned blocksize = dir->i_sb->s_blocksize;
734 	unsigned count = dx_get_count(entries), names = 0, space = 0, i;
735 	unsigned bcount = 0;
736 	struct buffer_head *bh;
737 	printk("%i indexed blocks...\n", count);
738 	for (i = 0; i < count; i++, entries++)
739 	{
740 		ext4_lblk_t block = dx_get_block(entries);
741 		ext4_lblk_t hash  = i ? dx_get_hash(entries): 0;
742 		u32 range = i < count - 1? (dx_get_hash(entries + 1) - hash): ~hash;
743 		struct stats stats;
744 		printk("%s%3u:%03u hash %8x/%8x ",levels?"":"   ", i, block, hash, range);
745 		bh = ext4_bread(NULL,dir, block, 0);
746 		if (!bh || IS_ERR(bh))
747 			continue;
748 		stats = levels?
749 		   dx_show_entries(hinfo, dir, ((struct dx_node *) bh->b_data)->entries, levels - 1):
750 		   dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *)
751 			bh->b_data, blocksize, 0);
752 		names += stats.names;
753 		space += stats.space;
754 		bcount += stats.bcount;
755 		brelse(bh);
756 	}
757 	if (bcount)
758 		printk(KERN_DEBUG "%snames %u, fullness %u (%u%%)\n",
759 		       levels ? "" : "   ", names, space/bcount,
760 		       (space/bcount)*100/blocksize);
761 	return (struct stats) { names, space, bcount};
762 }
763 #endif /* DX_DEBUG */
764 
765 /*
766  * Probe for a directory leaf block to search.
767  *
768  * dx_probe can return ERR_BAD_DX_DIR, which means there was a format
769  * error in the directory index, and the caller should fall back to
770  * searching the directory normally.  The callers of dx_probe **MUST**
771  * check for this error code, and make sure it never gets reflected
772  * back to userspace.
773  */
774 static struct dx_frame *
dx_probe(struct ext4_filename * fname,struct inode * dir,struct dx_hash_info * hinfo,struct dx_frame * frame_in)775 dx_probe(struct ext4_filename *fname, struct inode *dir,
776 	 struct dx_hash_info *hinfo, struct dx_frame *frame_in)
777 {
778 	unsigned count, indirect, level, i;
779 	struct dx_entry *at, *entries, *p, *q, *m;
780 	struct dx_root *root;
781 	struct dx_frame *frame = frame_in;
782 	struct dx_frame *ret_err = ERR_PTR(ERR_BAD_DX_DIR);
783 	u32 hash;
784 	ext4_lblk_t block;
785 	ext4_lblk_t blocks[EXT4_HTREE_LEVEL];
786 
787 	memset(frame_in, 0, EXT4_HTREE_LEVEL * sizeof(frame_in[0]));
788 	frame->bh = ext4_read_dirblock(dir, 0, INDEX);
789 	if (IS_ERR(frame->bh))
790 		return (struct dx_frame *) frame->bh;
791 
792 	root = (struct dx_root *) frame->bh->b_data;
793 	if (root->info.hash_version != DX_HASH_TEA &&
794 	    root->info.hash_version != DX_HASH_HALF_MD4 &&
795 	    root->info.hash_version != DX_HASH_LEGACY &&
796 	    root->info.hash_version != DX_HASH_SIPHASH) {
797 		ext4_warning_inode(dir, "Unrecognised inode hash code %u",
798 				   root->info.hash_version);
799 		goto fail;
800 	}
801 	if (ext4_hash_in_dirent(dir)) {
802 		if (root->info.hash_version != DX_HASH_SIPHASH) {
803 			ext4_warning_inode(dir,
804 				"Hash in dirent, but hash is not SIPHASH");
805 			goto fail;
806 		}
807 	} else {
808 		if (root->info.hash_version == DX_HASH_SIPHASH) {
809 			ext4_warning_inode(dir,
810 				"Hash code is SIPHASH, but hash not in dirent");
811 			goto fail;
812 		}
813 	}
814 	if (fname)
815 		hinfo = &fname->hinfo;
816 	hinfo->hash_version = root->info.hash_version;
817 	if (hinfo->hash_version <= DX_HASH_TEA)
818 		hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
819 	hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
820 	/* hash is already computed for encrypted casefolded directory */
821 	if (fname && fname_name(fname) &&
822 				!(IS_ENCRYPTED(dir) && IS_CASEFOLDED(dir)))
823 		ext4fs_dirhash(dir, fname_name(fname), fname_len(fname), hinfo);
824 	hash = hinfo->hash;
825 
826 	if (root->info.unused_flags & 1) {
827 		ext4_warning_inode(dir, "Unimplemented hash flags: %#06x",
828 				   root->info.unused_flags);
829 		goto fail;
830 	}
831 
832 	indirect = root->info.indirect_levels;
833 	if (indirect >= ext4_dir_htree_level(dir->i_sb)) {
834 		ext4_warning(dir->i_sb,
835 			     "Directory (ino: %lu) htree depth %#06x exceed"
836 			     "supported value", dir->i_ino,
837 			     ext4_dir_htree_level(dir->i_sb));
838 		if (ext4_dir_htree_level(dir->i_sb) < EXT4_HTREE_LEVEL) {
839 			ext4_warning(dir->i_sb, "Enable large directory "
840 						"feature to access it");
841 		}
842 		goto fail;
843 	}
844 
845 	entries = (struct dx_entry *)(((char *)&root->info) +
846 				      root->info.info_length);
847 
848 	if (dx_get_limit(entries) != dx_root_limit(dir,
849 						   root->info.info_length)) {
850 		ext4_warning_inode(dir, "dx entry: limit %u != root limit %u",
851 				   dx_get_limit(entries),
852 				   dx_root_limit(dir, root->info.info_length));
853 		goto fail;
854 	}
855 
856 	dxtrace(printk("Look up %x", hash));
857 	level = 0;
858 	blocks[0] = 0;
859 	while (1) {
860 		count = dx_get_count(entries);
861 		if (!count || count > dx_get_limit(entries)) {
862 			ext4_warning_inode(dir,
863 					   "dx entry: count %u beyond limit %u",
864 					   count, dx_get_limit(entries));
865 			goto fail;
866 		}
867 
868 		p = entries + 1;
869 		q = entries + count - 1;
870 		while (p <= q) {
871 			m = p + (q - p) / 2;
872 			dxtrace(printk(KERN_CONT "."));
873 			if (dx_get_hash(m) > hash)
874 				q = m - 1;
875 			else
876 				p = m + 1;
877 		}
878 
879 		if (0) { // linear search cross check
880 			unsigned n = count - 1;
881 			at = entries;
882 			while (n--)
883 			{
884 				dxtrace(printk(KERN_CONT ","));
885 				if (dx_get_hash(++at) > hash)
886 				{
887 					at--;
888 					break;
889 				}
890 			}
891 			assert (at == p - 1);
892 		}
893 
894 		at = p - 1;
895 		dxtrace(printk(KERN_CONT " %x->%u\n",
896 			       at == entries ? 0 : dx_get_hash(at),
897 			       dx_get_block(at)));
898 		frame->entries = entries;
899 		frame->at = at;
900 
901 		block = dx_get_block(at);
902 		for (i = 0; i <= level; i++) {
903 			if (blocks[i] == block) {
904 				ext4_warning_inode(dir,
905 					"dx entry: tree cycle block %u points back to block %u",
906 					blocks[level], block);
907 				goto fail;
908 			}
909 		}
910 		if (++level > indirect)
911 			return frame;
912 		blocks[level] = block;
913 		frame++;
914 		frame->bh = ext4_read_dirblock(dir, block, INDEX);
915 		if (IS_ERR(frame->bh)) {
916 			ret_err = (struct dx_frame *) frame->bh;
917 			frame->bh = NULL;
918 			goto fail;
919 		}
920 
921 		entries = ((struct dx_node *) frame->bh->b_data)->entries;
922 
923 		if (dx_get_limit(entries) != dx_node_limit(dir)) {
924 			ext4_warning_inode(dir,
925 				"dx entry: limit %u != node limit %u",
926 				dx_get_limit(entries), dx_node_limit(dir));
927 			goto fail;
928 		}
929 	}
930 fail:
931 	while (frame >= frame_in) {
932 		brelse(frame->bh);
933 		frame--;
934 	}
935 
936 	if (ret_err == ERR_PTR(ERR_BAD_DX_DIR))
937 		ext4_warning_inode(dir,
938 			"Corrupt directory, running e2fsck is recommended");
939 	return ret_err;
940 }
941 
dx_release(struct dx_frame * frames)942 static void dx_release(struct dx_frame *frames)
943 {
944 	struct dx_root_info *info;
945 	int i;
946 	unsigned int indirect_levels;
947 
948 	if (frames[0].bh == NULL)
949 		return;
950 
951 	info = &((struct dx_root *)frames[0].bh->b_data)->info;
952 	/* save local copy, "info" may be freed after brelse() */
953 	indirect_levels = info->indirect_levels;
954 	for (i = 0; i <= indirect_levels; i++) {
955 		if (frames[i].bh == NULL)
956 			break;
957 		brelse(frames[i].bh);
958 		frames[i].bh = NULL;
959 	}
960 }
961 
962 /*
963  * This function increments the frame pointer to search the next leaf
964  * block, and reads in the necessary intervening nodes if the search
965  * should be necessary.  Whether or not the search is necessary is
966  * controlled by the hash parameter.  If the hash value is even, then
967  * the search is only continued if the next block starts with that
968  * hash value.  This is used if we are searching for a specific file.
969  *
970  * If the hash value is HASH_NB_ALWAYS, then always go to the next block.
971  *
972  * This function returns 1 if the caller should continue to search,
973  * or 0 if it should not.  If there is an error reading one of the
974  * index blocks, it will a negative error code.
975  *
976  * If start_hash is non-null, it will be filled in with the starting
977  * hash of the next page.
978  */
ext4_htree_next_block(struct inode * dir,__u32 hash,struct dx_frame * frame,struct dx_frame * frames,__u32 * start_hash)979 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
980 				 struct dx_frame *frame,
981 				 struct dx_frame *frames,
982 				 __u32 *start_hash)
983 {
984 	struct dx_frame *p;
985 	struct buffer_head *bh;
986 	int num_frames = 0;
987 	__u32 bhash;
988 
989 	p = frame;
990 	/*
991 	 * Find the next leaf page by incrementing the frame pointer.
992 	 * If we run out of entries in the interior node, loop around and
993 	 * increment pointer in the parent node.  When we break out of
994 	 * this loop, num_frames indicates the number of interior
995 	 * nodes need to be read.
996 	 */
997 	while (1) {
998 		if (++(p->at) < p->entries + dx_get_count(p->entries))
999 			break;
1000 		if (p == frames)
1001 			return 0;
1002 		num_frames++;
1003 		p--;
1004 	}
1005 
1006 	/*
1007 	 * If the hash is 1, then continue only if the next page has a
1008 	 * continuation hash of any value.  This is used for readdir
1009 	 * handling.  Otherwise, check to see if the hash matches the
1010 	 * desired contiuation hash.  If it doesn't, return since
1011 	 * there's no point to read in the successive index pages.
1012 	 */
1013 	bhash = dx_get_hash(p->at);
1014 	if (start_hash)
1015 		*start_hash = bhash;
1016 	if ((hash & 1) == 0) {
1017 		if ((bhash & ~1) != hash)
1018 			return 0;
1019 	}
1020 	/*
1021 	 * If the hash is HASH_NB_ALWAYS, we always go to the next
1022 	 * block so no check is necessary
1023 	 */
1024 	while (num_frames--) {
1025 		bh = ext4_read_dirblock(dir, dx_get_block(p->at), INDEX);
1026 		if (IS_ERR(bh))
1027 			return PTR_ERR(bh);
1028 		p++;
1029 		brelse(p->bh);
1030 		p->bh = bh;
1031 		p->at = p->entries = ((struct dx_node *) bh->b_data)->entries;
1032 	}
1033 	return 1;
1034 }
1035 
1036 
1037 /*
1038  * This function fills a red-black tree with information from a
1039  * directory block.  It returns the number directory entries loaded
1040  * into the tree.  If there is an error it is returned in err.
1041  */
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)1042 static int htree_dirblock_to_tree(struct file *dir_file,
1043 				  struct inode *dir, ext4_lblk_t block,
1044 				  struct dx_hash_info *hinfo,
1045 				  __u32 start_hash, __u32 start_minor_hash)
1046 {
1047 	struct buffer_head *bh;
1048 	struct ext4_dir_entry_2 *de, *top;
1049 	int err = 0, count = 0;
1050 	struct fscrypt_str fname_crypto_str = FSTR_INIT(NULL, 0), tmp_str;
1051 	int csum = ext4_has_metadata_csum(dir->i_sb);
1052 
1053 	dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
1054 							(unsigned long)block));
1055 	bh = ext4_read_dirblock(dir, block, DIRENT_HTREE);
1056 	if (IS_ERR(bh))
1057 		return PTR_ERR(bh);
1058 
1059 	de = (struct ext4_dir_entry_2 *) bh->b_data;
1060 	/* csum entries are not larger in the casefolded encrypted case */
1061 	top = (struct ext4_dir_entry_2 *) ((char *) de +
1062 					   dir->i_sb->s_blocksize -
1063 					   ext4_dir_rec_len(0,
1064 							   csum ? NULL : dir));
1065 #ifdef CONFIG_FS_ENCRYPTION
1066 	/* Check if the directory is encrypted */
1067 	if (IS_ENCRYPTED(dir)) {
1068 		err = fscrypt_get_encryption_info(dir);
1069 		if (err < 0) {
1070 			brelse(bh);
1071 			return err;
1072 		}
1073 		err = fscrypt_fname_alloc_buffer(dir, EXT4_NAME_LEN,
1074 						     &fname_crypto_str);
1075 		if (err < 0) {
1076 			brelse(bh);
1077 			return err;
1078 		}
1079 	}
1080 #endif
1081 	for (; de < top; de = ext4_next_entry(de, dir->i_sb->s_blocksize)) {
1082 		if (ext4_check_dir_entry(dir, NULL, de, bh,
1083 				bh->b_data, bh->b_size,
1084 				(block<<EXT4_BLOCK_SIZE_BITS(dir->i_sb))
1085 					 + ((char *)de - bh->b_data))) {
1086 			/* silently ignore the rest of the block */
1087 			break;
1088 		}
1089 		if (ext4_hash_in_dirent(dir)) {
1090 			if (de->name_len && de->inode) {
1091 				hinfo->hash = EXT4_DIRENT_HASH(de);
1092 				hinfo->minor_hash = EXT4_DIRENT_MINOR_HASH(de);
1093 			} else {
1094 				hinfo->hash = 0;
1095 				hinfo->minor_hash = 0;
1096 			}
1097 		} else {
1098 			ext4fs_dirhash(dir, de->name, de->name_len, hinfo);
1099 		}
1100 		if ((hinfo->hash < start_hash) ||
1101 		    ((hinfo->hash == start_hash) &&
1102 		     (hinfo->minor_hash < start_minor_hash)))
1103 			continue;
1104 		if (de->inode == 0)
1105 			continue;
1106 		if (!IS_ENCRYPTED(dir)) {
1107 			tmp_str.name = de->name;
1108 			tmp_str.len = de->name_len;
1109 			err = ext4_htree_store_dirent(dir_file,
1110 				   hinfo->hash, hinfo->minor_hash, de,
1111 				   &tmp_str);
1112 		} else {
1113 			int save_len = fname_crypto_str.len;
1114 			struct fscrypt_str de_name = FSTR_INIT(de->name,
1115 								de->name_len);
1116 
1117 			/* Directory is encrypted */
1118 			err = fscrypt_fname_disk_to_usr(dir, hinfo->hash,
1119 					hinfo->minor_hash, &de_name,
1120 					&fname_crypto_str);
1121 			if (err) {
1122 				count = err;
1123 				goto errout;
1124 			}
1125 			err = ext4_htree_store_dirent(dir_file,
1126 				   hinfo->hash, hinfo->minor_hash, de,
1127 					&fname_crypto_str);
1128 			fname_crypto_str.len = save_len;
1129 		}
1130 		if (err != 0) {
1131 			count = err;
1132 			goto errout;
1133 		}
1134 		count++;
1135 	}
1136 errout:
1137 	brelse(bh);
1138 #ifdef CONFIG_FS_ENCRYPTION
1139 	fscrypt_fname_free_buffer(&fname_crypto_str);
1140 #endif
1141 	return count;
1142 }
1143 
1144 
1145 /*
1146  * This function fills a red-black tree with information from a
1147  * directory.  We start scanning the directory in hash order, starting
1148  * at start_hash and start_minor_hash.
1149  *
1150  * This function returns the number of entries inserted into the tree,
1151  * or a negative error code.
1152  */
ext4_htree_fill_tree(struct file * dir_file,__u32 start_hash,__u32 start_minor_hash,__u32 * next_hash)1153 int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
1154 			 __u32 start_minor_hash, __u32 *next_hash)
1155 {
1156 	struct dx_hash_info hinfo;
1157 	struct ext4_dir_entry_2 *de;
1158 	struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
1159 	struct inode *dir;
1160 	ext4_lblk_t block;
1161 	int count = 0;
1162 	int ret, err;
1163 	__u32 hashval;
1164 	struct fscrypt_str tmp_str;
1165 
1166 	dxtrace(printk(KERN_DEBUG "In htree_fill_tree, start hash: %x:%x\n",
1167 		       start_hash, start_minor_hash));
1168 	dir = file_inode(dir_file);
1169 	if (!(ext4_test_inode_flag(dir, EXT4_INODE_INDEX))) {
1170 		if (ext4_hash_in_dirent(dir))
1171 			hinfo.hash_version = DX_HASH_SIPHASH;
1172 		else
1173 			hinfo.hash_version =
1174 					EXT4_SB(dir->i_sb)->s_def_hash_version;
1175 		if (hinfo.hash_version <= DX_HASH_TEA)
1176 			hinfo.hash_version +=
1177 				EXT4_SB(dir->i_sb)->s_hash_unsigned;
1178 		hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
1179 		if (ext4_has_inline_data(dir)) {
1180 			int has_inline_data = 1;
1181 			count = ext4_inlinedir_to_tree(dir_file, dir, 0,
1182 						       &hinfo, start_hash,
1183 						       start_minor_hash,
1184 						       &has_inline_data);
1185 			if (has_inline_data) {
1186 				*next_hash = ~0;
1187 				return count;
1188 			}
1189 		}
1190 		count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
1191 					       start_hash, start_minor_hash);
1192 		*next_hash = ~0;
1193 		return count;
1194 	}
1195 	hinfo.hash = start_hash;
1196 	hinfo.minor_hash = 0;
1197 	frame = dx_probe(NULL, dir, &hinfo, frames);
1198 	if (IS_ERR(frame))
1199 		return PTR_ERR(frame);
1200 
1201 	/* Add '.' and '..' from the htree header */
1202 	if (!start_hash && !start_minor_hash) {
1203 		de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
1204 		tmp_str.name = de->name;
1205 		tmp_str.len = de->name_len;
1206 		err = ext4_htree_store_dirent(dir_file, 0, 0,
1207 					      de, &tmp_str);
1208 		if (err != 0)
1209 			goto errout;
1210 		count++;
1211 	}
1212 	if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) {
1213 		de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
1214 		de = ext4_next_entry(de, dir->i_sb->s_blocksize);
1215 		tmp_str.name = de->name;
1216 		tmp_str.len = de->name_len;
1217 		err = ext4_htree_store_dirent(dir_file, 2, 0,
1218 					      de, &tmp_str);
1219 		if (err != 0)
1220 			goto errout;
1221 		count++;
1222 	}
1223 
1224 	while (1) {
1225 		if (fatal_signal_pending(current)) {
1226 			err = -ERESTARTSYS;
1227 			goto errout;
1228 		}
1229 		cond_resched();
1230 		block = dx_get_block(frame->at);
1231 		ret = htree_dirblock_to_tree(dir_file, dir, block, &hinfo,
1232 					     start_hash, start_minor_hash);
1233 		if (ret < 0) {
1234 			err = ret;
1235 			goto errout;
1236 		}
1237 		count += ret;
1238 		hashval = ~0;
1239 		ret = ext4_htree_next_block(dir, HASH_NB_ALWAYS,
1240 					    frame, frames, &hashval);
1241 		*next_hash = hashval;
1242 		if (ret < 0) {
1243 			err = ret;
1244 			goto errout;
1245 		}
1246 		/*
1247 		 * Stop if:  (a) there are no more entries, or
1248 		 * (b) we have inserted at least one entry and the
1249 		 * next hash value is not a continuation
1250 		 */
1251 		if ((ret == 0) ||
1252 		    (count && ((hashval & 1) == 0)))
1253 			break;
1254 	}
1255 	dx_release(frames);
1256 	dxtrace(printk(KERN_DEBUG "Fill tree: returned %d entries, "
1257 		       "next hash: %x\n", count, *next_hash));
1258 	return count;
1259 errout:
1260 	dx_release(frames);
1261 	return (err);
1262 }
1263 
search_dirblock(struct buffer_head * bh,struct inode * dir,struct ext4_filename * fname,unsigned int offset,struct ext4_dir_entry_2 ** res_dir)1264 static inline int search_dirblock(struct buffer_head *bh,
1265 				  struct inode *dir,
1266 				  struct ext4_filename *fname,
1267 				  unsigned int offset,
1268 				  struct ext4_dir_entry_2 **res_dir)
1269 {
1270 	return ext4_search_dir(bh, bh->b_data, dir->i_sb->s_blocksize, dir,
1271 			       fname, offset, res_dir);
1272 }
1273 
1274 /*
1275  * Directory block splitting, compacting
1276  */
1277 
1278 /*
1279  * Create map of hash values, offsets, and sizes, stored at end of block.
1280  * Returns number of entries mapped.
1281  */
dx_make_map(struct inode * dir,struct buffer_head * bh,struct dx_hash_info * hinfo,struct dx_map_entry * map_tail)1282 static int dx_make_map(struct inode *dir, struct buffer_head *bh,
1283 		       struct dx_hash_info *hinfo,
1284 		       struct dx_map_entry *map_tail)
1285 {
1286 	int count = 0;
1287 	struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)bh->b_data;
1288 	unsigned int buflen = bh->b_size;
1289 	char *base = bh->b_data;
1290 	struct dx_hash_info h = *hinfo;
1291 	int blocksize = EXT4_BLOCK_SIZE(dir->i_sb);
1292 
1293 	if (ext4_has_metadata_csum(dir->i_sb))
1294 		buflen -= sizeof(struct ext4_dir_entry_tail);
1295 
1296 	while ((char *) de < base + buflen) {
1297 		if (ext4_check_dir_entry(dir, NULL, de, bh, base, buflen,
1298 					 ((char *)de) - base))
1299 			return -EFSCORRUPTED;
1300 		if (de->name_len && de->inode) {
1301 			if (ext4_hash_in_dirent(dir))
1302 				h.hash = EXT4_DIRENT_HASH(de);
1303 			else
1304 				ext4fs_dirhash(dir, de->name, de->name_len, &h);
1305 			map_tail--;
1306 			map_tail->hash = h.hash;
1307 			map_tail->offs = ((char *) de - base)>>2;
1308 			map_tail->size = ext4_rec_len_from_disk(de->rec_len,
1309 								blocksize);
1310 			count++;
1311 			cond_resched();
1312 		}
1313 		de = ext4_next_entry(de, blocksize);
1314 	}
1315 	return count;
1316 }
1317 
1318 /* Sort map by hash value */
dx_sort_map(struct dx_map_entry * map,unsigned count)1319 static void dx_sort_map (struct dx_map_entry *map, unsigned count)
1320 {
1321 	struct dx_map_entry *p, *q, *top = map + count - 1;
1322 	int more;
1323 	/* Combsort until bubble sort doesn't suck */
1324 	while (count > 2) {
1325 		count = count*10/13;
1326 		if (count - 9 < 2) /* 9, 10 -> 11 */
1327 			count = 11;
1328 		for (p = top, q = p - count; q >= map; p--, q--)
1329 			if (p->hash < q->hash)
1330 				swap(*p, *q);
1331 	}
1332 	/* Garden variety bubble sort */
1333 	do {
1334 		more = 0;
1335 		q = top;
1336 		while (q-- > map) {
1337 			if (q[1].hash >= q[0].hash)
1338 				continue;
1339 			swap(*(q+1), *q);
1340 			more = 1;
1341 		}
1342 	} while(more);
1343 }
1344 
dx_insert_block(struct dx_frame * frame,u32 hash,ext4_lblk_t block)1345 static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
1346 {
1347 	struct dx_entry *entries = frame->entries;
1348 	struct dx_entry *old = frame->at, *new = old + 1;
1349 	int count = dx_get_count(entries);
1350 
1351 	assert(count < dx_get_limit(entries));
1352 	assert(old < entries + count);
1353 	memmove(new + 1, new, (char *)(entries + count) - (char *)(new));
1354 	dx_set_hash(new, hash);
1355 	dx_set_block(new, block);
1356 	dx_set_count(entries, count + 1);
1357 }
1358 
1359 #ifdef CONFIG_UNICODE
1360 /*
1361  * Test whether a case-insensitive directory entry matches the filename
1362  * being searched for.  If quick is set, assume the name being looked up
1363  * is already in the casefolded form.
1364  *
1365  * Returns: 0 if the directory entry matches, more than 0 if it
1366  * doesn't match or less than zero on error.
1367  */
ext4_ci_compare(const struct inode * parent,const struct qstr * name,u8 * de_name,size_t de_name_len,bool quick)1368 static int ext4_ci_compare(const struct inode *parent, const struct qstr *name,
1369 			   u8 *de_name, size_t de_name_len, bool quick)
1370 {
1371 	const struct super_block *sb = parent->i_sb;
1372 	const struct unicode_map *um = sb->s_encoding;
1373 	struct fscrypt_str decrypted_name = FSTR_INIT(NULL, de_name_len);
1374 	struct qstr entry = QSTR_INIT(de_name, de_name_len);
1375 	int ret;
1376 
1377 	if (IS_ENCRYPTED(parent)) {
1378 		const struct fscrypt_str encrypted_name =
1379 				FSTR_INIT(de_name, de_name_len);
1380 
1381 		decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL);
1382 		if (!decrypted_name.name)
1383 			return -ENOMEM;
1384 		ret = fscrypt_fname_disk_to_usr(parent, 0, 0, &encrypted_name,
1385 						&decrypted_name);
1386 		if (ret < 0)
1387 			goto out;
1388 		entry.name = decrypted_name.name;
1389 		entry.len = decrypted_name.len;
1390 	}
1391 
1392 	if (quick)
1393 		ret = utf8_strncasecmp_folded(um, name, &entry);
1394 	else
1395 		ret = utf8_strncasecmp(um, name, &entry);
1396 	if (ret < 0) {
1397 		/* Handle invalid character sequence as either an error
1398 		 * or as an opaque byte sequence.
1399 		 */
1400 		if (sb_has_enc_strict_mode(sb))
1401 			ret = -EINVAL;
1402 		else if (name->len != entry.len)
1403 			ret = 1;
1404 		else
1405 			ret = !!memcmp(name->name, entry.name, entry.len);
1406 	}
1407 out:
1408 	kfree(decrypted_name.name);
1409 	return ret;
1410 }
1411 
ext4_fname_setup_ci_filename(struct inode * dir,const struct qstr * iname,struct ext4_filename * name)1412 int ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
1413 				  struct ext4_filename *name)
1414 {
1415 	struct fscrypt_str *cf_name = &name->cf_name;
1416 	struct dx_hash_info *hinfo = &name->hinfo;
1417 	int len;
1418 
1419 	if (!IS_CASEFOLDED(dir) || !dir->i_sb->s_encoding ||
1420 	    (IS_ENCRYPTED(dir) && !fscrypt_has_encryption_key(dir))) {
1421 		cf_name->name = NULL;
1422 		return 0;
1423 	}
1424 
1425 	cf_name->name = kmalloc(EXT4_NAME_LEN, GFP_NOFS);
1426 	if (!cf_name->name)
1427 		return -ENOMEM;
1428 
1429 	len = utf8_casefold(dir->i_sb->s_encoding,
1430 			    iname, cf_name->name,
1431 			    EXT4_NAME_LEN);
1432 	if (len <= 0) {
1433 		kfree(cf_name->name);
1434 		cf_name->name = NULL;
1435 	}
1436 	cf_name->len = (unsigned) len;
1437 	if (!IS_ENCRYPTED(dir))
1438 		return 0;
1439 
1440 	hinfo->hash_version = DX_HASH_SIPHASH;
1441 	hinfo->seed = NULL;
1442 	if (cf_name->name)
1443 		ext4fs_dirhash(dir, cf_name->name, cf_name->len, hinfo);
1444 	else
1445 		ext4fs_dirhash(dir, iname->name, iname->len, hinfo);
1446 	return 0;
1447 }
1448 #endif
1449 
1450 /*
1451  * Test whether a directory entry matches the filename being searched for.
1452  *
1453  * Return: %true if the directory entry matches, otherwise %false.
1454  */
ext4_match(struct inode * parent,const struct ext4_filename * fname,struct ext4_dir_entry_2 * de)1455 static bool ext4_match(struct inode *parent,
1456 			      const struct ext4_filename *fname,
1457 			      struct ext4_dir_entry_2 *de)
1458 {
1459 	struct fscrypt_name f;
1460 
1461 	if (!de->inode)
1462 		return false;
1463 
1464 	f.usr_fname = fname->usr_fname;
1465 	f.disk_name = fname->disk_name;
1466 #ifdef CONFIG_FS_ENCRYPTION
1467 	f.crypto_buf = fname->crypto_buf;
1468 #endif
1469 
1470 #ifdef CONFIG_UNICODE
1471 	if (parent->i_sb->s_encoding && IS_CASEFOLDED(parent) &&
1472 	    (!IS_ENCRYPTED(parent) || fscrypt_has_encryption_key(parent))) {
1473 		if (fname->cf_name.name) {
1474 			struct qstr cf = {.name = fname->cf_name.name,
1475 					  .len = fname->cf_name.len};
1476 			if (IS_ENCRYPTED(parent)) {
1477 				if (fname->hinfo.hash != EXT4_DIRENT_HASH(de) ||
1478 					fname->hinfo.minor_hash !=
1479 						EXT4_DIRENT_MINOR_HASH(de)) {
1480 
1481 					return 0;
1482 				}
1483 			}
1484 			return !ext4_ci_compare(parent, &cf, de->name,
1485 							de->name_len, true);
1486 		}
1487 		return !ext4_ci_compare(parent, fname->usr_fname, de->name,
1488 						de->name_len, false);
1489 	}
1490 #endif
1491 
1492 	return fscrypt_match_name(&f, de->name, de->name_len);
1493 }
1494 
1495 /*
1496  * Returns 0 if not found, -1 on failure, and 1 on success
1497  */
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)1498 int ext4_search_dir(struct buffer_head *bh, char *search_buf, int buf_size,
1499 		    struct inode *dir, struct ext4_filename *fname,
1500 		    unsigned int offset, struct ext4_dir_entry_2 **res_dir)
1501 {
1502 	struct ext4_dir_entry_2 * de;
1503 	char * dlimit;
1504 	int de_len;
1505 
1506 	de = (struct ext4_dir_entry_2 *)search_buf;
1507 	dlimit = search_buf + buf_size;
1508 	while ((char *) de < dlimit - EXT4_BASE_DIR_LEN) {
1509 		/* this code is executed quadratically often */
1510 		/* do minimal checking `by hand' */
1511 		if (de->name + de->name_len <= dlimit &&
1512 		    ext4_match(dir, fname, de)) {
1513 			/* found a match - just to be sure, do
1514 			 * a full check */
1515 			if (ext4_check_dir_entry(dir, NULL, de, bh, search_buf,
1516 						 buf_size, offset))
1517 				return -1;
1518 			*res_dir = de;
1519 			return 1;
1520 		}
1521 		/* prevent looping on a bad block */
1522 		de_len = ext4_rec_len_from_disk(de->rec_len,
1523 						dir->i_sb->s_blocksize);
1524 		if (de_len <= 0)
1525 			return -1;
1526 		offset += de_len;
1527 		de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
1528 	}
1529 	return 0;
1530 }
1531 
is_dx_internal_node(struct inode * dir,ext4_lblk_t block,struct ext4_dir_entry * de)1532 static int is_dx_internal_node(struct inode *dir, ext4_lblk_t block,
1533 			       struct ext4_dir_entry *de)
1534 {
1535 	struct super_block *sb = dir->i_sb;
1536 
1537 	if (!is_dx(dir))
1538 		return 0;
1539 	if (block == 0)
1540 		return 1;
1541 	if (de->inode == 0 &&
1542 	    ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) ==
1543 			sb->s_blocksize)
1544 		return 1;
1545 	return 0;
1546 }
1547 
1548 /*
1549  *	__ext4_find_entry()
1550  *
1551  * finds an entry in the specified directory with the wanted name. It
1552  * returns the cache buffer in which the entry was found, and the entry
1553  * itself (as a parameter - res_dir). It does NOT read the inode of the
1554  * entry - you'll have to do that yourself if you want to.
1555  *
1556  * The returned buffer_head has ->b_count elevated.  The caller is expected
1557  * to brelse() it when appropriate.
1558  */
__ext4_find_entry(struct inode * dir,struct ext4_filename * fname,struct ext4_dir_entry_2 ** res_dir,int * inlined)1559 static struct buffer_head *__ext4_find_entry(struct inode *dir,
1560 					     struct ext4_filename *fname,
1561 					     struct ext4_dir_entry_2 **res_dir,
1562 					     int *inlined)
1563 {
1564 	struct super_block *sb;
1565 	struct buffer_head *bh_use[NAMEI_RA_SIZE];
1566 	struct buffer_head *bh, *ret = NULL;
1567 	ext4_lblk_t start, block;
1568 	const u8 *name = fname->usr_fname->name;
1569 	size_t ra_max = 0;	/* Number of bh's in the readahead
1570 				   buffer, bh_use[] */
1571 	size_t ra_ptr = 0;	/* Current index into readahead
1572 				   buffer */
1573 	ext4_lblk_t  nblocks;
1574 	int i, namelen, retval;
1575 
1576 	*res_dir = NULL;
1577 	sb = dir->i_sb;
1578 	namelen = fname->usr_fname->len;
1579 	if (namelen > EXT4_NAME_LEN)
1580 		return NULL;
1581 
1582 	if (ext4_has_inline_data(dir)) {
1583 		int has_inline_data = 1;
1584 		ret = ext4_find_inline_entry(dir, fname, res_dir,
1585 					     &has_inline_data);
1586 		if (inlined)
1587 			*inlined = has_inline_data;
1588 		if (has_inline_data)
1589 			goto cleanup_and_exit;
1590 	}
1591 
1592 	if ((namelen <= 2) && (name[0] == '.') &&
1593 	    (name[1] == '.' || name[1] == '\0')) {
1594 		/*
1595 		 * "." or ".." will only be in the first block
1596 		 * NFS may look up ".."; "." should be handled by the VFS
1597 		 */
1598 		block = start = 0;
1599 		nblocks = 1;
1600 		goto restart;
1601 	}
1602 	if (is_dx(dir)) {
1603 		ret = ext4_dx_find_entry(dir, fname, res_dir);
1604 		/*
1605 		 * On success, or if the error was file not found,
1606 		 * return.  Otherwise, fall back to doing a search the
1607 		 * old fashioned way.
1608 		 */
1609 		if (!IS_ERR(ret) || PTR_ERR(ret) != ERR_BAD_DX_DIR)
1610 			goto cleanup_and_exit;
1611 		dxtrace(printk(KERN_DEBUG "ext4_find_entry: dx failed, "
1612 			       "falling back\n"));
1613 		ret = NULL;
1614 	}
1615 	nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1616 	if (!nblocks) {
1617 		ret = NULL;
1618 		goto cleanup_and_exit;
1619 	}
1620 	start = EXT4_I(dir)->i_dir_start_lookup;
1621 	if (start >= nblocks)
1622 		start = 0;
1623 	block = start;
1624 restart:
1625 	do {
1626 		/*
1627 		 * We deal with the read-ahead logic here.
1628 		 */
1629 		cond_resched();
1630 		if (ra_ptr >= ra_max) {
1631 			/* Refill the readahead buffer */
1632 			ra_ptr = 0;
1633 			if (block < start)
1634 				ra_max = start - block;
1635 			else
1636 				ra_max = nblocks - block;
1637 			ra_max = min(ra_max, ARRAY_SIZE(bh_use));
1638 			retval = ext4_bread_batch(dir, block, ra_max,
1639 						  false /* wait */, bh_use);
1640 			if (retval) {
1641 				ret = ERR_PTR(retval);
1642 				ra_max = 0;
1643 				goto cleanup_and_exit;
1644 			}
1645 		}
1646 		if ((bh = bh_use[ra_ptr++]) == NULL)
1647 			goto next;
1648 		wait_on_buffer(bh);
1649 		if (!buffer_uptodate(bh)) {
1650 			EXT4_ERROR_INODE(dir, "reading directory lblock %lu",
1651 					 (unsigned long) block);
1652 			brelse(bh);
1653 			ret = ERR_PTR(-EIO);
1654 			goto cleanup_and_exit;
1655 		}
1656 		if (!buffer_verified(bh) &&
1657 		    !is_dx_internal_node(dir, block,
1658 					 (struct ext4_dir_entry *)bh->b_data) &&
1659 		    !ext4_dirblock_csum_verify(dir, bh)) {
1660 			EXT4_ERROR_INODE(dir, "checksumming directory "
1661 					 "block %lu", (unsigned long)block);
1662 			brelse(bh);
1663 			ret = ERR_PTR(-EFSBADCRC);
1664 			goto cleanup_and_exit;
1665 		}
1666 		set_buffer_verified(bh);
1667 		i = search_dirblock(bh, dir, fname,
1668 			    block << EXT4_BLOCK_SIZE_BITS(sb), res_dir);
1669 		if (i == 1) {
1670 			EXT4_I(dir)->i_dir_start_lookup = block;
1671 			ret = bh;
1672 			goto cleanup_and_exit;
1673 		} else {
1674 			brelse(bh);
1675 			if (i < 0)
1676 				goto cleanup_and_exit;
1677 		}
1678 	next:
1679 		if (++block >= nblocks)
1680 			block = 0;
1681 	} while (block != start);
1682 
1683 	/*
1684 	 * If the directory has grown while we were searching, then
1685 	 * search the last part of the directory before giving up.
1686 	 */
1687 	block = nblocks;
1688 	nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1689 	if (block < nblocks) {
1690 		start = 0;
1691 		goto restart;
1692 	}
1693 
1694 cleanup_and_exit:
1695 	/* Clean up the read-ahead blocks */
1696 	for (; ra_ptr < ra_max; ra_ptr++)
1697 		brelse(bh_use[ra_ptr]);
1698 	return ret;
1699 }
1700 
ext4_find_entry(struct inode * dir,const struct qstr * d_name,struct ext4_dir_entry_2 ** res_dir,int * inlined)1701 static struct buffer_head *ext4_find_entry(struct inode *dir,
1702 					   const struct qstr *d_name,
1703 					   struct ext4_dir_entry_2 **res_dir,
1704 					   int *inlined)
1705 {
1706 	int err;
1707 	struct ext4_filename fname;
1708 	struct buffer_head *bh;
1709 
1710 	err = ext4_fname_setup_filename(dir, d_name, 1, &fname);
1711 	if (err == -ENOENT)
1712 		return NULL;
1713 	if (err)
1714 		return ERR_PTR(err);
1715 
1716 	bh = __ext4_find_entry(dir, &fname, res_dir, inlined);
1717 
1718 	ext4_fname_free_filename(&fname);
1719 	return bh;
1720 }
1721 
ext4_lookup_entry(struct inode * dir,struct dentry * dentry,struct ext4_dir_entry_2 ** res_dir)1722 static struct buffer_head *ext4_lookup_entry(struct inode *dir,
1723 					     struct dentry *dentry,
1724 					     struct ext4_dir_entry_2 **res_dir)
1725 {
1726 	int err;
1727 	struct ext4_filename fname;
1728 	struct buffer_head *bh;
1729 
1730 	err = ext4_fname_prepare_lookup(dir, dentry, &fname);
1731 	generic_set_encrypted_ci_d_ops(dir, dentry);
1732 	if (err == -ENOENT)
1733 		return NULL;
1734 	if (err)
1735 		return ERR_PTR(err);
1736 
1737 	bh = __ext4_find_entry(dir, &fname, res_dir, NULL);
1738 
1739 	ext4_fname_free_filename(&fname);
1740 	return bh;
1741 }
1742 
ext4_dx_find_entry(struct inode * dir,struct ext4_filename * fname,struct ext4_dir_entry_2 ** res_dir)1743 static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
1744 			struct ext4_filename *fname,
1745 			struct ext4_dir_entry_2 **res_dir)
1746 {
1747 	struct super_block * sb = dir->i_sb;
1748 	struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
1749 	struct buffer_head *bh;
1750 	ext4_lblk_t block;
1751 	int retval;
1752 
1753 #ifdef CONFIG_FS_ENCRYPTION
1754 	*res_dir = NULL;
1755 #endif
1756 	frame = dx_probe(fname, dir, NULL, frames);
1757 	if (IS_ERR(frame))
1758 		return (struct buffer_head *) frame;
1759 	do {
1760 		block = dx_get_block(frame->at);
1761 		bh = ext4_read_dirblock(dir, block, DIRENT_HTREE);
1762 		if (IS_ERR(bh))
1763 			goto errout;
1764 
1765 		retval = search_dirblock(bh, dir, fname,
1766 					 block << EXT4_BLOCK_SIZE_BITS(sb),
1767 					 res_dir);
1768 		if (retval == 1)
1769 			goto success;
1770 		brelse(bh);
1771 		if (retval == -1) {
1772 			bh = ERR_PTR(ERR_BAD_DX_DIR);
1773 			goto errout;
1774 		}
1775 
1776 		/* Check to see if we should continue to search */
1777 		retval = ext4_htree_next_block(dir, fname->hinfo.hash, frame,
1778 					       frames, NULL);
1779 		if (retval < 0) {
1780 			ext4_warning_inode(dir,
1781 				"error %d reading directory index block",
1782 				retval);
1783 			bh = ERR_PTR(retval);
1784 			goto errout;
1785 		}
1786 	} while (retval == 1);
1787 
1788 	bh = NULL;
1789 errout:
1790 	dxtrace(printk(KERN_DEBUG "%s not found\n", fname->usr_fname->name));
1791 success:
1792 	dx_release(frames);
1793 	return bh;
1794 }
1795 
ext4_lookup(struct inode * dir,struct dentry * dentry,unsigned int flags)1796 static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
1797 {
1798 	struct inode *inode;
1799 	struct ext4_dir_entry_2 *de;
1800 	struct buffer_head *bh;
1801 
1802 	if (dentry->d_name.len > EXT4_NAME_LEN)
1803 		return ERR_PTR(-ENAMETOOLONG);
1804 
1805 	bh = ext4_lookup_entry(dir, dentry, &de);
1806 	if (IS_ERR(bh))
1807 		return ERR_CAST(bh);
1808 	inode = NULL;
1809 	if (bh) {
1810 		__u32 ino = le32_to_cpu(de->inode);
1811 		brelse(bh);
1812 		if (!ext4_valid_inum(dir->i_sb, ino)) {
1813 			EXT4_ERROR_INODE(dir, "bad inode number: %u", ino);
1814 			return ERR_PTR(-EFSCORRUPTED);
1815 		}
1816 		if (unlikely(ino == dir->i_ino)) {
1817 			EXT4_ERROR_INODE(dir, "'%pd' linked to parent dir",
1818 					 dentry);
1819 			return ERR_PTR(-EFSCORRUPTED);
1820 		}
1821 		inode = ext4_iget(dir->i_sb, ino, EXT4_IGET_NORMAL);
1822 		if (inode == ERR_PTR(-ESTALE)) {
1823 			EXT4_ERROR_INODE(dir,
1824 					 "deleted inode referenced: %u",
1825 					 ino);
1826 			return ERR_PTR(-EFSCORRUPTED);
1827 		}
1828 		if (!IS_ERR(inode) && IS_ENCRYPTED(dir) &&
1829 		    (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) &&
1830 		    !fscrypt_has_permitted_context(dir, inode)) {
1831 			ext4_warning(inode->i_sb,
1832 				     "Inconsistent encryption contexts: %lu/%lu",
1833 				     dir->i_ino, inode->i_ino);
1834 			iput(inode);
1835 			return ERR_PTR(-EPERM);
1836 		}
1837 	}
1838 
1839 #ifdef CONFIG_UNICODE
1840 	if (!inode && IS_CASEFOLDED(dir)) {
1841 		/* Eventually we want to call d_add_ci(dentry, NULL)
1842 		 * for negative dentries in the encoding case as
1843 		 * well.  For now, prevent the negative dentry
1844 		 * from being cached.
1845 		 */
1846 		return NULL;
1847 	}
1848 #endif
1849 	return d_splice_alias(inode, dentry);
1850 }
1851 
1852 
ext4_get_parent(struct dentry * child)1853 struct dentry *ext4_get_parent(struct dentry *child)
1854 {
1855 	__u32 ino;
1856 	static const struct qstr dotdot = QSTR_INIT("..", 2);
1857 	struct ext4_dir_entry_2 * de;
1858 	struct buffer_head *bh;
1859 
1860 	bh = ext4_find_entry(d_inode(child), &dotdot, &de, NULL);
1861 	if (IS_ERR(bh))
1862 		return ERR_CAST(bh);
1863 	if (!bh)
1864 		return ERR_PTR(-ENOENT);
1865 	ino = le32_to_cpu(de->inode);
1866 	brelse(bh);
1867 
1868 	if (!ext4_valid_inum(child->d_sb, ino)) {
1869 		EXT4_ERROR_INODE(d_inode(child),
1870 				 "bad parent inode number: %u", ino);
1871 		return ERR_PTR(-EFSCORRUPTED);
1872 	}
1873 
1874 	return d_obtain_alias(ext4_iget(child->d_sb, ino, EXT4_IGET_NORMAL));
1875 }
1876 
1877 /*
1878  * Move count entries from end of map between two memory locations.
1879  * Returns pointer to last entry moved.
1880  */
1881 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)1882 dx_move_dirents(struct inode *dir, char *from, char *to,
1883 		struct dx_map_entry *map, int count,
1884 		unsigned blocksize)
1885 {
1886 	unsigned rec_len = 0;
1887 
1888 	while (count--) {
1889 		struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)
1890 						(from + (map->offs<<2));
1891 		rec_len = ext4_dir_rec_len(de->name_len, dir);
1892 
1893 		memcpy (to, de, rec_len);
1894 		((struct ext4_dir_entry_2 *) to)->rec_len =
1895 				ext4_rec_len_to_disk(rec_len, blocksize);
1896 		de->inode = 0;
1897 		map++;
1898 		to += rec_len;
1899 	}
1900 	return (struct ext4_dir_entry_2 *) (to - rec_len);
1901 }
1902 
1903 /*
1904  * Compact each dir entry in the range to the minimal rec_len.
1905  * Returns pointer to last entry in range.
1906  */
dx_pack_dirents(struct inode * dir,char * base,unsigned int blocksize)1907 static struct ext4_dir_entry_2 *dx_pack_dirents(struct inode *dir, char *base,
1908 							unsigned int blocksize)
1909 {
1910 	struct ext4_dir_entry_2 *next, *to, *prev, *de = (struct ext4_dir_entry_2 *) base;
1911 	unsigned rec_len = 0;
1912 
1913 	prev = to = de;
1914 	while ((char*)de < base + blocksize) {
1915 		next = ext4_next_entry(de, blocksize);
1916 		if (de->inode && de->name_len) {
1917 			rec_len = ext4_dir_rec_len(de->name_len, dir);
1918 			if (de > to)
1919 				memmove(to, de, rec_len);
1920 			to->rec_len = ext4_rec_len_to_disk(rec_len, blocksize);
1921 			prev = to;
1922 			to = (struct ext4_dir_entry_2 *) (((char *) to) + rec_len);
1923 		}
1924 		de = next;
1925 	}
1926 	return prev;
1927 }
1928 
1929 /*
1930  * Split a full leaf block to make room for a new dir entry.
1931  * Allocate a new block, and move entries so that they are approx. equally full.
1932  * Returns pointer to de in block into which the new entry will be inserted.
1933  */
do_split(handle_t * handle,struct inode * dir,struct buffer_head ** bh,struct dx_frame * frame,struct dx_hash_info * hinfo)1934 static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
1935 			struct buffer_head **bh,struct dx_frame *frame,
1936 			struct dx_hash_info *hinfo)
1937 {
1938 	unsigned blocksize = dir->i_sb->s_blocksize;
1939 	unsigned continued;
1940 	int count;
1941 	struct buffer_head *bh2;
1942 	ext4_lblk_t newblock;
1943 	u32 hash2;
1944 	struct dx_map_entry *map;
1945 	char *data1 = (*bh)->b_data, *data2;
1946 	unsigned split, move, size;
1947 	struct ext4_dir_entry_2 *de = NULL, *de2;
1948 	int	csum_size = 0;
1949 	int	err = 0, i;
1950 
1951 	if (ext4_has_metadata_csum(dir->i_sb))
1952 		csum_size = sizeof(struct ext4_dir_entry_tail);
1953 
1954 	bh2 = ext4_append(handle, dir, &newblock);
1955 	if (IS_ERR(bh2)) {
1956 		brelse(*bh);
1957 		*bh = NULL;
1958 		return (struct ext4_dir_entry_2 *) bh2;
1959 	}
1960 
1961 	BUFFER_TRACE(*bh, "get_write_access");
1962 	err = ext4_journal_get_write_access(handle, *bh);
1963 	if (err)
1964 		goto journal_error;
1965 
1966 	BUFFER_TRACE(frame->bh, "get_write_access");
1967 	err = ext4_journal_get_write_access(handle, frame->bh);
1968 	if (err)
1969 		goto journal_error;
1970 
1971 	data2 = bh2->b_data;
1972 
1973 	/* create map in the end of data2 block */
1974 	map = (struct dx_map_entry *) (data2 + blocksize);
1975 	count = dx_make_map(dir, *bh, hinfo, map);
1976 	if (count < 0) {
1977 		err = count;
1978 		goto journal_error;
1979 	}
1980 	map -= count;
1981 	dx_sort_map(map, count);
1982 	/* Ensure that neither split block is over half full */
1983 	size = 0;
1984 	move = 0;
1985 	for (i = count-1; i >= 0; i--) {
1986 		/* is more than half of this entry in 2nd half of the block? */
1987 		if (size + map[i].size/2 > blocksize/2)
1988 			break;
1989 		size += map[i].size;
1990 		move++;
1991 	}
1992 	/*
1993 	 * map index at which we will split
1994 	 *
1995 	 * If the sum of active entries didn't exceed half the block size, just
1996 	 * split it in half by count; each resulting block will have at least
1997 	 * half the space free.
1998 	 */
1999 	if (i > 0)
2000 		split = count - move;
2001 	else
2002 		split = count/2;
2003 
2004 	hash2 = map[split].hash;
2005 	continued = hash2 == map[split - 1].hash;
2006 	dxtrace(printk(KERN_INFO "Split block %lu at %x, %i/%i\n",
2007 			(unsigned long)dx_get_block(frame->at),
2008 					hash2, split, count-split));
2009 
2010 	/* Fancy dance to stay within two buffers */
2011 	de2 = dx_move_dirents(dir, data1, data2, map + split, count - split,
2012 			      blocksize);
2013 	de = dx_pack_dirents(dir, data1, blocksize);
2014 	de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
2015 					   (char *) de,
2016 					   blocksize);
2017 	de2->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
2018 					    (char *) de2,
2019 					    blocksize);
2020 	if (csum_size) {
2021 		ext4_initialize_dirent_tail(*bh, blocksize);
2022 		ext4_initialize_dirent_tail(bh2, blocksize);
2023 	}
2024 
2025 	dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data1,
2026 			blocksize, 1));
2027 	dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data2,
2028 			blocksize, 1));
2029 
2030 	/* Which block gets the new entry? */
2031 	if (hinfo->hash >= hash2) {
2032 		swap(*bh, bh2);
2033 		de = de2;
2034 	}
2035 	dx_insert_block(frame, hash2 + continued, newblock);
2036 	err = ext4_handle_dirty_dirblock(handle, dir, bh2);
2037 	if (err)
2038 		goto journal_error;
2039 	err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
2040 	if (err)
2041 		goto journal_error;
2042 	brelse(bh2);
2043 	dxtrace(dx_show_index("frame", frame->entries));
2044 	return de;
2045 
2046 journal_error:
2047 	brelse(*bh);
2048 	brelse(bh2);
2049 	*bh = NULL;
2050 	ext4_std_error(dir->i_sb, err);
2051 	return ERR_PTR(err);
2052 }
2053 
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)2054 int ext4_find_dest_de(struct inode *dir, struct inode *inode,
2055 		      struct buffer_head *bh,
2056 		      void *buf, int buf_size,
2057 		      struct ext4_filename *fname,
2058 		      struct ext4_dir_entry_2 **dest_de)
2059 {
2060 	struct ext4_dir_entry_2 *de;
2061 	unsigned short reclen = ext4_dir_rec_len(fname_len(fname), dir);
2062 	int nlen, rlen;
2063 	unsigned int offset = 0;
2064 	char *top;
2065 
2066 	de = (struct ext4_dir_entry_2 *)buf;
2067 	top = buf + buf_size - reclen;
2068 	while ((char *) de <= top) {
2069 		if (ext4_check_dir_entry(dir, NULL, de, bh,
2070 					 buf, buf_size, offset))
2071 			return -EFSCORRUPTED;
2072 		if (ext4_match(dir, fname, de))
2073 			return -EEXIST;
2074 		nlen = ext4_dir_rec_len(de->name_len, dir);
2075 		rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
2076 		if ((de->inode ? rlen - nlen : rlen) >= reclen)
2077 			break;
2078 		de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
2079 		offset += rlen;
2080 	}
2081 	if ((char *) de > top)
2082 		return -ENOSPC;
2083 
2084 	*dest_de = de;
2085 	return 0;
2086 }
2087 
ext4_insert_dentry(struct inode * dir,struct inode * inode,struct ext4_dir_entry_2 * de,int buf_size,struct ext4_filename * fname)2088 void ext4_insert_dentry(struct inode *dir,
2089 			struct inode *inode,
2090 			struct ext4_dir_entry_2 *de,
2091 			int buf_size,
2092 			struct ext4_filename *fname)
2093 {
2094 
2095 	int nlen, rlen;
2096 
2097 	nlen = ext4_dir_rec_len(de->name_len, dir);
2098 	rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
2099 	if (de->inode) {
2100 		struct ext4_dir_entry_2 *de1 =
2101 			(struct ext4_dir_entry_2 *)((char *)de + nlen);
2102 		de1->rec_len = ext4_rec_len_to_disk(rlen - nlen, buf_size);
2103 		de->rec_len = ext4_rec_len_to_disk(nlen, buf_size);
2104 		de = de1;
2105 	}
2106 	de->file_type = EXT4_FT_UNKNOWN;
2107 	de->inode = cpu_to_le32(inode->i_ino);
2108 	ext4_set_de_type(inode->i_sb, de, inode->i_mode);
2109 	de->name_len = fname_len(fname);
2110 	memcpy(de->name, fname_name(fname), fname_len(fname));
2111 	if (ext4_hash_in_dirent(dir)) {
2112 		struct dx_hash_info *hinfo = &fname->hinfo;
2113 
2114 		EXT4_DIRENT_HASHES(de)->hash = cpu_to_le32(hinfo->hash);
2115 		EXT4_DIRENT_HASHES(de)->minor_hash =
2116 						cpu_to_le32(hinfo->minor_hash);
2117 	}
2118 }
2119 
2120 /*
2121  * Add a new entry into a directory (leaf) block.  If de is non-NULL,
2122  * it points to a directory entry which is guaranteed to be large
2123  * enough for new directory entry.  If de is NULL, then
2124  * add_dirent_to_buf will attempt search the directory block for
2125  * space.  It will return -ENOSPC if no space is available, and -EIO
2126  * and -EEXIST if directory entry already exists.
2127  */
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)2128 static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
2129 			     struct inode *dir,
2130 			     struct inode *inode, struct ext4_dir_entry_2 *de,
2131 			     struct buffer_head *bh)
2132 {
2133 	unsigned int	blocksize = dir->i_sb->s_blocksize;
2134 	int		csum_size = 0;
2135 	int		err;
2136 
2137 	if (ext4_has_metadata_csum(inode->i_sb))
2138 		csum_size = sizeof(struct ext4_dir_entry_tail);
2139 
2140 	if (!de) {
2141 		err = ext4_find_dest_de(dir, inode, bh, bh->b_data,
2142 					blocksize - csum_size, fname, &de);
2143 		if (err)
2144 			return err;
2145 	}
2146 	BUFFER_TRACE(bh, "get_write_access");
2147 	err = ext4_journal_get_write_access(handle, bh);
2148 	if (err) {
2149 		ext4_std_error(dir->i_sb, err);
2150 		return err;
2151 	}
2152 
2153 	/* By now the buffer is marked for journaling */
2154 	ext4_insert_dentry(dir, inode, de, blocksize, fname);
2155 
2156 	/*
2157 	 * XXX shouldn't update any times until successful
2158 	 * completion of syscall, but too many callers depend
2159 	 * on this.
2160 	 *
2161 	 * XXX similarly, too many callers depend on
2162 	 * ext4_new_inode() setting the times, but error
2163 	 * recovery deletes the inode, so the worst that can
2164 	 * happen is that the times are slightly out of date
2165 	 * and/or different from the directory change time.
2166 	 */
2167 	dir->i_mtime = dir->i_ctime = current_time(dir);
2168 	ext4_update_dx_flag(dir);
2169 	inode_inc_iversion(dir);
2170 	ext4_mark_inode_dirty(handle, dir);
2171 	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
2172 	err = ext4_handle_dirty_dirblock(handle, dir, bh);
2173 	if (err)
2174 		ext4_std_error(dir->i_sb, err);
2175 	return 0;
2176 }
2177 
2178 /*
2179  * This converts a one block unindexed directory to a 3 block indexed
2180  * directory, and adds the dentry to the indexed directory.
2181  */
make_indexed_dir(handle_t * handle,struct ext4_filename * fname,struct inode * dir,struct inode * inode,struct buffer_head * bh)2182 static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
2183 			    struct inode *dir,
2184 			    struct inode *inode, struct buffer_head *bh)
2185 {
2186 	struct buffer_head *bh2;
2187 	struct dx_root	*root;
2188 	struct dx_frame	frames[EXT4_HTREE_LEVEL], *frame;
2189 	struct dx_entry *entries;
2190 	struct ext4_dir_entry_2	*de, *de2;
2191 	char		*data2, *top;
2192 	unsigned	len;
2193 	int		retval;
2194 	unsigned	blocksize;
2195 	ext4_lblk_t  block;
2196 	struct fake_dirent *fde;
2197 	int csum_size = 0;
2198 
2199 	if (ext4_has_metadata_csum(inode->i_sb))
2200 		csum_size = sizeof(struct ext4_dir_entry_tail);
2201 
2202 	blocksize =  dir->i_sb->s_blocksize;
2203 	dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino));
2204 	BUFFER_TRACE(bh, "get_write_access");
2205 	retval = ext4_journal_get_write_access(handle, bh);
2206 	if (retval) {
2207 		ext4_std_error(dir->i_sb, retval);
2208 		brelse(bh);
2209 		return retval;
2210 	}
2211 	root = (struct dx_root *) bh->b_data;
2212 
2213 	/* The 0th block becomes the root, move the dirents out */
2214 	fde = &root->dotdot;
2215 	de = (struct ext4_dir_entry_2 *)((char *)fde +
2216 		ext4_rec_len_from_disk(fde->rec_len, blocksize));
2217 	if ((char *) de >= (((char *) root) + blocksize)) {
2218 		EXT4_ERROR_INODE(dir, "invalid rec_len for '..'");
2219 		brelse(bh);
2220 		return -EFSCORRUPTED;
2221 	}
2222 	len = ((char *) root) + (blocksize - csum_size) - (char *) de;
2223 
2224 	/* Allocate new block for the 0th block's dirents */
2225 	bh2 = ext4_append(handle, dir, &block);
2226 	if (IS_ERR(bh2)) {
2227 		brelse(bh);
2228 		return PTR_ERR(bh2);
2229 	}
2230 	ext4_set_inode_flag(dir, EXT4_INODE_INDEX);
2231 	data2 = bh2->b_data;
2232 
2233 	memcpy(data2, de, len);
2234 	de = (struct ext4_dir_entry_2 *) data2;
2235 	top = data2 + len;
2236 	while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top) {
2237 		if (ext4_check_dir_entry(dir, NULL, de, bh2, data2, len,
2238 					 (data2 + (blocksize - csum_size) -
2239 					  (char *) de))) {
2240 			brelse(bh2);
2241 			brelse(bh);
2242 			return -EFSCORRUPTED;
2243 		}
2244 		de = de2;
2245 	}
2246 	de->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
2247 					   (char *) de, blocksize);
2248 
2249 	if (csum_size)
2250 		ext4_initialize_dirent_tail(bh2, blocksize);
2251 
2252 	/* Initialize the root; the dot dirents already exist */
2253 	de = (struct ext4_dir_entry_2 *) (&root->dotdot);
2254 	de->rec_len = ext4_rec_len_to_disk(
2255 			blocksize - ext4_dir_rec_len(2, NULL), blocksize);
2256 	memset (&root->info, 0, sizeof(root->info));
2257 	root->info.info_length = sizeof(root->info);
2258 	if (ext4_hash_in_dirent(dir))
2259 		root->info.hash_version = DX_HASH_SIPHASH;
2260 	else
2261 		root->info.hash_version =
2262 				EXT4_SB(dir->i_sb)->s_def_hash_version;
2263 
2264 	entries = root->entries;
2265 	dx_set_block(entries, 1);
2266 	dx_set_count(entries, 1);
2267 	dx_set_limit(entries, dx_root_limit(dir, sizeof(root->info)));
2268 
2269 	/* Initialize as for dx_probe */
2270 	fname->hinfo.hash_version = root->info.hash_version;
2271 	if (fname->hinfo.hash_version <= DX_HASH_TEA)
2272 		fname->hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
2273 	fname->hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
2274 
2275 	/* casefolded encrypted hashes are computed on fname setup */
2276 	if (!ext4_hash_in_dirent(dir))
2277 		ext4fs_dirhash(dir, fname_name(fname),
2278 				fname_len(fname), &fname->hinfo);
2279 
2280 	memset(frames, 0, sizeof(frames));
2281 	frame = frames;
2282 	frame->entries = entries;
2283 	frame->at = entries;
2284 	frame->bh = bh;
2285 
2286 	retval = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
2287 	if (retval)
2288 		goto out_frames;
2289 	retval = ext4_handle_dirty_dirblock(handle, dir, bh2);
2290 	if (retval)
2291 		goto out_frames;
2292 
2293 	de = do_split(handle,dir, &bh2, frame, &fname->hinfo);
2294 	if (IS_ERR(de)) {
2295 		retval = PTR_ERR(de);
2296 		goto out_frames;
2297 	}
2298 
2299 	retval = add_dirent_to_buf(handle, fname, dir, inode, de, bh2);
2300 out_frames:
2301 	/*
2302 	 * Even if the block split failed, we have to properly write
2303 	 * out all the changes we did so far. Otherwise we can end up
2304 	 * with corrupted filesystem.
2305 	 */
2306 	if (retval)
2307 		ext4_mark_inode_dirty(handle, dir);
2308 	dx_release(frames);
2309 	brelse(bh2);
2310 	return retval;
2311 }
2312 
2313 /*
2314  *	ext4_add_entry()
2315  *
2316  * adds a file entry to the specified directory, using the same
2317  * semantics as ext4_find_entry(). It returns NULL if it failed.
2318  *
2319  * NOTE!! The inode part of 'de' is left at 0 - which means you
2320  * may not sleep between calling this and putting something into
2321  * the entry, as someone else might have used it while you slept.
2322  */
ext4_add_entry(handle_t * handle,struct dentry * dentry,struct inode * inode)2323 static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
2324 			  struct inode *inode)
2325 {
2326 	struct inode *dir = d_inode(dentry->d_parent);
2327 	struct buffer_head *bh = NULL;
2328 	struct ext4_dir_entry_2 *de;
2329 	struct super_block *sb;
2330 	struct ext4_filename fname;
2331 	int	retval;
2332 	int	dx_fallback=0;
2333 	unsigned blocksize;
2334 	ext4_lblk_t block, blocks;
2335 	int	csum_size = 0;
2336 
2337 	if (ext4_has_metadata_csum(inode->i_sb))
2338 		csum_size = sizeof(struct ext4_dir_entry_tail);
2339 
2340 	sb = dir->i_sb;
2341 	blocksize = sb->s_blocksize;
2342 	if (!dentry->d_name.len)
2343 		return -EINVAL;
2344 
2345 	if (fscrypt_is_nokey_name(dentry))
2346 		return -ENOKEY;
2347 
2348 #ifdef CONFIG_UNICODE
2349 	if (sb_has_enc_strict_mode(sb) && IS_CASEFOLDED(dir) &&
2350 	    sb->s_encoding && utf8_validate(sb->s_encoding, &dentry->d_name))
2351 		return -EINVAL;
2352 #endif
2353 
2354 	retval = ext4_fname_setup_filename(dir, &dentry->d_name, 0, &fname);
2355 	if (retval)
2356 		return retval;
2357 
2358 	if (ext4_has_inline_data(dir)) {
2359 		retval = ext4_try_add_inline_entry(handle, &fname, dir, inode);
2360 		if (retval < 0)
2361 			goto out;
2362 		if (retval == 1) {
2363 			retval = 0;
2364 			goto out;
2365 		}
2366 	}
2367 
2368 	if (is_dx(dir)) {
2369 		retval = ext4_dx_add_entry(handle, &fname, dir, inode);
2370 		if (!retval || (retval != ERR_BAD_DX_DIR))
2371 			goto out;
2372 		/* Can we just ignore htree data? */
2373 		if (ext4_has_metadata_csum(sb)) {
2374 			EXT4_ERROR_INODE(dir,
2375 				"Directory has corrupted htree index.");
2376 			retval = -EFSCORRUPTED;
2377 			goto out;
2378 		}
2379 		ext4_clear_inode_flag(dir, EXT4_INODE_INDEX);
2380 		dx_fallback++;
2381 		ext4_mark_inode_dirty(handle, dir);
2382 	}
2383 	blocks = dir->i_size >> sb->s_blocksize_bits;
2384 	for (block = 0; block < blocks; block++) {
2385 		bh = ext4_read_dirblock(dir, block, DIRENT);
2386 		if (bh == NULL) {
2387 			bh = ext4_bread(handle, dir, block,
2388 					EXT4_GET_BLOCKS_CREATE);
2389 			goto add_to_new_block;
2390 		}
2391 		if (IS_ERR(bh)) {
2392 			retval = PTR_ERR(bh);
2393 			bh = NULL;
2394 			goto out;
2395 		}
2396 		retval = add_dirent_to_buf(handle, &fname, dir, inode,
2397 					   NULL, bh);
2398 		if (retval != -ENOSPC)
2399 			goto out;
2400 
2401 		if (blocks == 1 && !dx_fallback &&
2402 		    ext4_has_feature_dir_index(sb)) {
2403 			retval = make_indexed_dir(handle, &fname, dir,
2404 						  inode, bh);
2405 			bh = NULL; /* make_indexed_dir releases bh */
2406 			goto out;
2407 		}
2408 		brelse(bh);
2409 	}
2410 	bh = ext4_append(handle, dir, &block);
2411 add_to_new_block:
2412 	if (IS_ERR(bh)) {
2413 		retval = PTR_ERR(bh);
2414 		bh = NULL;
2415 		goto out;
2416 	}
2417 	de = (struct ext4_dir_entry_2 *) bh->b_data;
2418 	de->inode = 0;
2419 	de->rec_len = ext4_rec_len_to_disk(blocksize - csum_size, blocksize);
2420 
2421 	if (csum_size)
2422 		ext4_initialize_dirent_tail(bh, blocksize);
2423 
2424 	retval = add_dirent_to_buf(handle, &fname, dir, inode, de, bh);
2425 out:
2426 	ext4_fname_free_filename(&fname);
2427 	brelse(bh);
2428 	if (retval == 0)
2429 		ext4_set_inode_state(inode, EXT4_STATE_NEWENTRY);
2430 	return retval;
2431 }
2432 
2433 /*
2434  * Returns 0 for success, or a negative error value
2435  */
ext4_dx_add_entry(handle_t * handle,struct ext4_filename * fname,struct inode * dir,struct inode * inode)2436 static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
2437 			     struct inode *dir, struct inode *inode)
2438 {
2439 	struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
2440 	struct dx_entry *entries, *at;
2441 	struct buffer_head *bh;
2442 	struct super_block *sb = dir->i_sb;
2443 	struct ext4_dir_entry_2 *de;
2444 	int restart;
2445 	int err;
2446 
2447 again:
2448 	restart = 0;
2449 	frame = dx_probe(fname, dir, NULL, frames);
2450 	if (IS_ERR(frame))
2451 		return PTR_ERR(frame);
2452 	entries = frame->entries;
2453 	at = frame->at;
2454 	bh = ext4_read_dirblock(dir, dx_get_block(frame->at), DIRENT_HTREE);
2455 	if (IS_ERR(bh)) {
2456 		err = PTR_ERR(bh);
2457 		bh = NULL;
2458 		goto cleanup;
2459 	}
2460 
2461 	BUFFER_TRACE(bh, "get_write_access");
2462 	err = ext4_journal_get_write_access(handle, bh);
2463 	if (err)
2464 		goto journal_error;
2465 
2466 	err = add_dirent_to_buf(handle, fname, dir, inode, NULL, bh);
2467 	if (err != -ENOSPC)
2468 		goto cleanup;
2469 
2470 	err = 0;
2471 	/* Block full, should compress but for now just split */
2472 	dxtrace(printk(KERN_DEBUG "using %u of %u node entries\n",
2473 		       dx_get_count(entries), dx_get_limit(entries)));
2474 	/* Need to split index? */
2475 	if (dx_get_count(entries) == dx_get_limit(entries)) {
2476 		ext4_lblk_t newblock;
2477 		int levels = frame - frames + 1;
2478 		unsigned int icount;
2479 		int add_level = 1;
2480 		struct dx_entry *entries2;
2481 		struct dx_node *node2;
2482 		struct buffer_head *bh2;
2483 
2484 		while (frame > frames) {
2485 			if (dx_get_count((frame - 1)->entries) <
2486 			    dx_get_limit((frame - 1)->entries)) {
2487 				add_level = 0;
2488 				break;
2489 			}
2490 			frame--; /* split higher index block */
2491 			at = frame->at;
2492 			entries = frame->entries;
2493 			restart = 1;
2494 		}
2495 		if (add_level && levels == ext4_dir_htree_level(sb)) {
2496 			ext4_warning(sb, "Directory (ino: %lu) index full, "
2497 					 "reach max htree level :%d",
2498 					 dir->i_ino, levels);
2499 			if (ext4_dir_htree_level(sb) < EXT4_HTREE_LEVEL) {
2500 				ext4_warning(sb, "Large directory feature is "
2501 						 "not enabled on this "
2502 						 "filesystem");
2503 			}
2504 			err = -ENOSPC;
2505 			goto cleanup;
2506 		}
2507 		icount = dx_get_count(entries);
2508 		bh2 = ext4_append(handle, dir, &newblock);
2509 		if (IS_ERR(bh2)) {
2510 			err = PTR_ERR(bh2);
2511 			goto cleanup;
2512 		}
2513 		node2 = (struct dx_node *)(bh2->b_data);
2514 		entries2 = node2->entries;
2515 		memset(&node2->fake, 0, sizeof(struct fake_dirent));
2516 		node2->fake.rec_len = ext4_rec_len_to_disk(sb->s_blocksize,
2517 							   sb->s_blocksize);
2518 		BUFFER_TRACE(frame->bh, "get_write_access");
2519 		err = ext4_journal_get_write_access(handle, frame->bh);
2520 		if (err)
2521 			goto journal_error;
2522 		if (!add_level) {
2523 			unsigned icount1 = icount/2, icount2 = icount - icount1;
2524 			unsigned hash2 = dx_get_hash(entries + icount1);
2525 			dxtrace(printk(KERN_DEBUG "Split index %i/%i\n",
2526 				       icount1, icount2));
2527 
2528 			BUFFER_TRACE(frame->bh, "get_write_access"); /* index root */
2529 			err = ext4_journal_get_write_access(handle,
2530 							     (frame - 1)->bh);
2531 			if (err)
2532 				goto journal_error;
2533 
2534 			memcpy((char *) entries2, (char *) (entries + icount1),
2535 			       icount2 * sizeof(struct dx_entry));
2536 			dx_set_count(entries, icount1);
2537 			dx_set_count(entries2, icount2);
2538 			dx_set_limit(entries2, dx_node_limit(dir));
2539 
2540 			/* Which index block gets the new entry? */
2541 			if (at - entries >= icount1) {
2542 				frame->at = at = at - entries - icount1 + entries2;
2543 				frame->entries = entries = entries2;
2544 				swap(frame->bh, bh2);
2545 			}
2546 			dx_insert_block((frame - 1), hash2, newblock);
2547 			dxtrace(dx_show_index("node", frame->entries));
2548 			dxtrace(dx_show_index("node",
2549 			       ((struct dx_node *) bh2->b_data)->entries));
2550 			err = ext4_handle_dirty_dx_node(handle, dir, bh2);
2551 			if (err)
2552 				goto journal_error;
2553 			brelse (bh2);
2554 			err = ext4_handle_dirty_dx_node(handle, dir,
2555 						   (frame - 1)->bh);
2556 			if (err)
2557 				goto journal_error;
2558 			err = ext4_handle_dirty_dx_node(handle, dir,
2559 							frame->bh);
2560 			if (restart || err)
2561 				goto journal_error;
2562 		} else {
2563 			struct dx_root *dxroot;
2564 			memcpy((char *) entries2, (char *) entries,
2565 			       icount * sizeof(struct dx_entry));
2566 			dx_set_limit(entries2, dx_node_limit(dir));
2567 
2568 			/* Set up root */
2569 			dx_set_count(entries, 1);
2570 			dx_set_block(entries + 0, newblock);
2571 			dxroot = (struct dx_root *)frames[0].bh->b_data;
2572 			dxroot->info.indirect_levels += 1;
2573 			dxtrace(printk(KERN_DEBUG
2574 				       "Creating %d level index...\n",
2575 				       dxroot->info.indirect_levels));
2576 			err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
2577 			if (err)
2578 				goto journal_error;
2579 			err = ext4_handle_dirty_dx_node(handle, dir, bh2);
2580 			brelse(bh2);
2581 			restart = 1;
2582 			goto journal_error;
2583 		}
2584 	}
2585 	de = do_split(handle, dir, &bh, frame, &fname->hinfo);
2586 	if (IS_ERR(de)) {
2587 		err = PTR_ERR(de);
2588 		goto cleanup;
2589 	}
2590 	err = add_dirent_to_buf(handle, fname, dir, inode, de, bh);
2591 	goto cleanup;
2592 
2593 journal_error:
2594 	ext4_std_error(dir->i_sb, err); /* this is a no-op if err == 0 */
2595 cleanup:
2596 	brelse(bh);
2597 	dx_release(frames);
2598 	/* @restart is true means htree-path has been changed, we need to
2599 	 * repeat dx_probe() to find out valid htree-path
2600 	 */
2601 	if (restart && err == 0)
2602 		goto again;
2603 	return err;
2604 }
2605 
2606 /*
2607  * ext4_generic_delete_entry deletes a directory entry by merging it
2608  * with the previous entry
2609  */
ext4_generic_delete_entry(handle_t * handle,struct inode * dir,struct ext4_dir_entry_2 * de_del,struct buffer_head * bh,void * entry_buf,int buf_size,int csum_size)2610 int ext4_generic_delete_entry(handle_t *handle,
2611 			      struct inode *dir,
2612 			      struct ext4_dir_entry_2 *de_del,
2613 			      struct buffer_head *bh,
2614 			      void *entry_buf,
2615 			      int buf_size,
2616 			      int csum_size)
2617 {
2618 	struct ext4_dir_entry_2 *de, *pde;
2619 	unsigned int blocksize = dir->i_sb->s_blocksize;
2620 	int i;
2621 
2622 	i = 0;
2623 	pde = NULL;
2624 	de = (struct ext4_dir_entry_2 *)entry_buf;
2625 	while (i < buf_size - csum_size) {
2626 		if (ext4_check_dir_entry(dir, NULL, de, bh,
2627 					 entry_buf, buf_size, i))
2628 			return -EFSCORRUPTED;
2629 		if (de == de_del)  {
2630 			if (pde)
2631 				pde->rec_len = ext4_rec_len_to_disk(
2632 					ext4_rec_len_from_disk(pde->rec_len,
2633 							       blocksize) +
2634 					ext4_rec_len_from_disk(de->rec_len,
2635 							       blocksize),
2636 					blocksize);
2637 			else
2638 				de->inode = 0;
2639 			inode_inc_iversion(dir);
2640 			return 0;
2641 		}
2642 		i += ext4_rec_len_from_disk(de->rec_len, blocksize);
2643 		pde = de;
2644 		de = ext4_next_entry(de, blocksize);
2645 	}
2646 	return -ENOENT;
2647 }
2648 
ext4_delete_entry(handle_t * handle,struct inode * dir,struct ext4_dir_entry_2 * de_del,struct buffer_head * bh)2649 static int ext4_delete_entry(handle_t *handle,
2650 			     struct inode *dir,
2651 			     struct ext4_dir_entry_2 *de_del,
2652 			     struct buffer_head *bh)
2653 {
2654 	int err, csum_size = 0;
2655 
2656 	if (ext4_has_inline_data(dir)) {
2657 		int has_inline_data = 1;
2658 		err = ext4_delete_inline_entry(handle, dir, de_del, bh,
2659 					       &has_inline_data);
2660 		if (has_inline_data)
2661 			return err;
2662 	}
2663 
2664 	if (ext4_has_metadata_csum(dir->i_sb))
2665 		csum_size = sizeof(struct ext4_dir_entry_tail);
2666 
2667 	BUFFER_TRACE(bh, "get_write_access");
2668 	err = ext4_journal_get_write_access(handle, bh);
2669 	if (unlikely(err))
2670 		goto out;
2671 
2672 	err = ext4_generic_delete_entry(handle, dir, de_del,
2673 					bh, bh->b_data,
2674 					dir->i_sb->s_blocksize, csum_size);
2675 	if (err)
2676 		goto out;
2677 
2678 	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
2679 	err = ext4_handle_dirty_dirblock(handle, dir, bh);
2680 	if (unlikely(err))
2681 		goto out;
2682 
2683 	return 0;
2684 out:
2685 	if (err != -ENOENT)
2686 		ext4_std_error(dir->i_sb, err);
2687 	return err;
2688 }
2689 
2690 /*
2691  * Set directory link count to 1 if nlinks > EXT4_LINK_MAX, or if nlinks == 2
2692  * since this indicates that nlinks count was previously 1 to avoid overflowing
2693  * the 16-bit i_links_count field on disk.  Directories with i_nlink == 1 mean
2694  * that subdirectory link counts are not being maintained accurately.
2695  *
2696  * The caller has already checked for i_nlink overflow in case the DIR_LINK
2697  * feature is not enabled and returned -EMLINK.  The is_dx() check is a proxy
2698  * for checking S_ISDIR(inode) (since the INODE_INDEX feature will not be set
2699  * on regular files) and to avoid creating huge/slow non-HTREE directories.
2700  */
ext4_inc_count(handle_t * handle,struct inode * inode)2701 static void ext4_inc_count(handle_t *handle, struct inode *inode)
2702 {
2703 	inc_nlink(inode);
2704 	if (is_dx(inode) &&
2705 	    (inode->i_nlink > EXT4_LINK_MAX || inode->i_nlink == 2))
2706 		set_nlink(inode, 1);
2707 }
2708 
2709 /*
2710  * If a directory had nlink == 1, then we should let it be 1. This indicates
2711  * directory has >EXT4_LINK_MAX subdirs.
2712  */
ext4_dec_count(handle_t * handle,struct inode * inode)2713 static void ext4_dec_count(handle_t *handle, struct inode *inode)
2714 {
2715 	if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
2716 		drop_nlink(inode);
2717 }
2718 
2719 
ext4_add_nondir(handle_t * handle,struct dentry * dentry,struct inode * inode)2720 static int ext4_add_nondir(handle_t *handle,
2721 		struct dentry *dentry, struct inode *inode)
2722 {
2723 	int err = ext4_add_entry(handle, dentry, inode);
2724 	if (!err) {
2725 		ext4_mark_inode_dirty(handle, inode);
2726 		d_instantiate_new(dentry, inode);
2727 		return 0;
2728 	}
2729 	drop_nlink(inode);
2730 	unlock_new_inode(inode);
2731 	iput(inode);
2732 	return err;
2733 }
2734 
2735 /*
2736  * By the time this is called, we already have created
2737  * the directory cache entry for the new file, but it
2738  * is so far negative - it has no inode.
2739  *
2740  * If the create succeeds, we fill in the inode information
2741  * with d_instantiate().
2742  */
ext4_create(struct inode * dir,struct dentry * dentry,umode_t mode,bool excl)2743 static int ext4_create(struct inode *dir, struct dentry *dentry, umode_t mode,
2744 		       bool excl)
2745 {
2746 	handle_t *handle;
2747 	struct inode *inode;
2748 	int err, credits, retries = 0;
2749 
2750 	err = dquot_initialize(dir);
2751 	if (err)
2752 		return err;
2753 
2754 	credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2755 		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2756 retry:
2757 	inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2758 					    NULL, EXT4_HT_DIR, credits);
2759 	handle = ext4_journal_current_handle();
2760 	err = PTR_ERR(inode);
2761 	if (!IS_ERR(inode)) {
2762 		inode->i_op = &ext4_file_inode_operations;
2763 		inode->i_fop = &ext4_file_operations;
2764 		ext4_set_aops(inode);
2765 		err = ext4_add_nondir(handle, dentry, inode);
2766 		if (!err && IS_DIRSYNC(dir))
2767 			ext4_handle_sync(handle);
2768 	}
2769 	if (handle)
2770 		ext4_journal_stop(handle);
2771 	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2772 		goto retry;
2773 	return err;
2774 }
2775 
ext4_mknod(struct inode * dir,struct dentry * dentry,umode_t mode,dev_t rdev)2776 static int ext4_mknod(struct inode *dir, struct dentry *dentry,
2777 		      umode_t mode, dev_t rdev)
2778 {
2779 	handle_t *handle;
2780 	struct inode *inode;
2781 	int err, credits, retries = 0;
2782 
2783 	err = dquot_initialize(dir);
2784 	if (err)
2785 		return err;
2786 
2787 	credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2788 		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2789 retry:
2790 	inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2791 					    NULL, EXT4_HT_DIR, credits);
2792 	handle = ext4_journal_current_handle();
2793 	err = PTR_ERR(inode);
2794 	if (!IS_ERR(inode)) {
2795 		init_special_inode(inode, inode->i_mode, rdev);
2796 		inode->i_op = &ext4_special_inode_operations;
2797 		err = ext4_add_nondir(handle, dentry, inode);
2798 		if (!err && IS_DIRSYNC(dir))
2799 			ext4_handle_sync(handle);
2800 	}
2801 	if (handle)
2802 		ext4_journal_stop(handle);
2803 	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2804 		goto retry;
2805 	return err;
2806 }
2807 
ext4_tmpfile(struct inode * dir,struct dentry * dentry,umode_t mode)2808 static int ext4_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
2809 {
2810 	handle_t *handle;
2811 	struct inode *inode;
2812 	int err, retries = 0;
2813 
2814 	err = dquot_initialize(dir);
2815 	if (err)
2816 		return err;
2817 
2818 retry:
2819 	inode = ext4_new_inode_start_handle(dir, mode,
2820 					    NULL, 0, NULL,
2821 					    EXT4_HT_DIR,
2822 			EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
2823 			  4 + EXT4_XATTR_TRANS_BLOCKS);
2824 	handle = ext4_journal_current_handle();
2825 	err = PTR_ERR(inode);
2826 	if (!IS_ERR(inode)) {
2827 		inode->i_op = &ext4_file_inode_operations;
2828 		inode->i_fop = &ext4_file_operations;
2829 		ext4_set_aops(inode);
2830 		d_tmpfile(dentry, inode);
2831 		err = ext4_orphan_add(handle, inode);
2832 		if (err)
2833 			goto err_unlock_inode;
2834 		mark_inode_dirty(inode);
2835 		unlock_new_inode(inode);
2836 	}
2837 	if (handle)
2838 		ext4_journal_stop(handle);
2839 	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2840 		goto retry;
2841 	return err;
2842 err_unlock_inode:
2843 	ext4_journal_stop(handle);
2844 	unlock_new_inode(inode);
2845 	return err;
2846 }
2847 
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)2848 struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
2849 			  struct ext4_dir_entry_2 *de,
2850 			  int blocksize, int csum_size,
2851 			  unsigned int parent_ino, int dotdot_real_len)
2852 {
2853 	de->inode = cpu_to_le32(inode->i_ino);
2854 	de->name_len = 1;
2855 	de->rec_len = ext4_rec_len_to_disk(ext4_dir_rec_len(de->name_len, NULL),
2856 					   blocksize);
2857 	strcpy(de->name, ".");
2858 	ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2859 
2860 	de = ext4_next_entry(de, blocksize);
2861 	de->inode = cpu_to_le32(parent_ino);
2862 	de->name_len = 2;
2863 	if (!dotdot_real_len)
2864 		de->rec_len = ext4_rec_len_to_disk(blocksize -
2865 					(csum_size + ext4_dir_rec_len(1, NULL)),
2866 					blocksize);
2867 	else
2868 		de->rec_len = ext4_rec_len_to_disk(
2869 					ext4_dir_rec_len(de->name_len, NULL),
2870 					blocksize);
2871 	strcpy(de->name, "..");
2872 	ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2873 
2874 	return ext4_next_entry(de, blocksize);
2875 }
2876 
ext4_init_new_dir(handle_t * handle,struct inode * dir,struct inode * inode)2877 static int ext4_init_new_dir(handle_t *handle, struct inode *dir,
2878 			     struct inode *inode)
2879 {
2880 	struct buffer_head *dir_block = NULL;
2881 	struct ext4_dir_entry_2 *de;
2882 	ext4_lblk_t block = 0;
2883 	unsigned int blocksize = dir->i_sb->s_blocksize;
2884 	int csum_size = 0;
2885 	int err;
2886 
2887 	if (ext4_has_metadata_csum(dir->i_sb))
2888 		csum_size = sizeof(struct ext4_dir_entry_tail);
2889 
2890 	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2891 		err = ext4_try_create_inline_dir(handle, dir, inode);
2892 		if (err < 0 && err != -ENOSPC)
2893 			goto out;
2894 		if (!err)
2895 			goto out;
2896 	}
2897 
2898 	inode->i_size = 0;
2899 	dir_block = ext4_append(handle, inode, &block);
2900 	if (IS_ERR(dir_block))
2901 		return PTR_ERR(dir_block);
2902 	de = (struct ext4_dir_entry_2 *)dir_block->b_data;
2903 	ext4_init_dot_dotdot(inode, de, blocksize, csum_size, dir->i_ino, 0);
2904 	set_nlink(inode, 2);
2905 	if (csum_size)
2906 		ext4_initialize_dirent_tail(dir_block, blocksize);
2907 
2908 	BUFFER_TRACE(dir_block, "call ext4_handle_dirty_metadata");
2909 	err = ext4_handle_dirty_dirblock(handle, inode, dir_block);
2910 	if (err)
2911 		goto out;
2912 	set_buffer_verified(dir_block);
2913 out:
2914 	brelse(dir_block);
2915 	return err;
2916 }
2917 
ext4_mkdir(struct inode * dir,struct dentry * dentry,umode_t mode)2918 static int ext4_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
2919 {
2920 	handle_t *handle;
2921 	struct inode *inode;
2922 	int err, credits, retries = 0;
2923 
2924 	if (EXT4_DIR_LINK_MAX(dir))
2925 		return -EMLINK;
2926 
2927 	err = dquot_initialize(dir);
2928 	if (err)
2929 		return err;
2930 
2931 	credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2932 		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2933 retry:
2934 	inode = ext4_new_inode_start_handle(dir, S_IFDIR | mode,
2935 					    &dentry->d_name,
2936 					    0, NULL, EXT4_HT_DIR, credits);
2937 	handle = ext4_journal_current_handle();
2938 	err = PTR_ERR(inode);
2939 	if (IS_ERR(inode))
2940 		goto out_stop;
2941 
2942 	inode->i_op = &ext4_dir_inode_operations;
2943 	inode->i_fop = &ext4_dir_operations;
2944 	err = ext4_init_new_dir(handle, dir, inode);
2945 	if (err)
2946 		goto out_clear_inode;
2947 	err = ext4_mark_inode_dirty(handle, inode);
2948 	if (!err)
2949 		err = ext4_add_entry(handle, dentry, inode);
2950 	if (err) {
2951 out_clear_inode:
2952 		clear_nlink(inode);
2953 		unlock_new_inode(inode);
2954 		ext4_mark_inode_dirty(handle, inode);
2955 		iput(inode);
2956 		goto out_stop;
2957 	}
2958 	ext4_inc_count(handle, dir);
2959 	ext4_update_dx_flag(dir);
2960 	err = ext4_mark_inode_dirty(handle, dir);
2961 	if (err)
2962 		goto out_clear_inode;
2963 	d_instantiate_new(dentry, inode);
2964 	if (IS_DIRSYNC(dir))
2965 		ext4_handle_sync(handle);
2966 
2967 out_stop:
2968 	if (handle)
2969 		ext4_journal_stop(handle);
2970 	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2971 		goto retry;
2972 	return err;
2973 }
2974 
2975 /*
2976  * routine to check that the specified directory is empty (for rmdir)
2977  */
ext4_empty_dir(struct inode * inode)2978 bool ext4_empty_dir(struct inode *inode)
2979 {
2980 	unsigned int offset;
2981 	struct buffer_head *bh;
2982 	struct ext4_dir_entry_2 *de;
2983 	struct super_block *sb;
2984 
2985 	if (ext4_has_inline_data(inode)) {
2986 		int has_inline_data = 1;
2987 		int ret;
2988 
2989 		ret = empty_inline_dir(inode, &has_inline_data);
2990 		if (has_inline_data)
2991 			return ret;
2992 	}
2993 
2994 	sb = inode->i_sb;
2995 	if (inode->i_size < ext4_dir_rec_len(1, NULL) +
2996 					ext4_dir_rec_len(2, NULL)) {
2997 		EXT4_ERROR_INODE(inode, "invalid size");
2998 		return true;
2999 	}
3000 	/* The first directory block must not be a hole,
3001 	 * so treat it as DIRENT_HTREE
3002 	 */
3003 	bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE);
3004 	if (IS_ERR(bh))
3005 		return true;
3006 
3007 	de = (struct ext4_dir_entry_2 *) bh->b_data;
3008 	if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data, bh->b_size,
3009 				 0) ||
3010 	    le32_to_cpu(de->inode) != inode->i_ino || strcmp(".", de->name)) {
3011 		ext4_warning_inode(inode, "directory missing '.'");
3012 		brelse(bh);
3013 		return true;
3014 	}
3015 	offset = ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
3016 	de = ext4_next_entry(de, sb->s_blocksize);
3017 	if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data, bh->b_size,
3018 				 offset) ||
3019 	    le32_to_cpu(de->inode) == 0 || strcmp("..", de->name)) {
3020 		ext4_warning_inode(inode, "directory missing '..'");
3021 		brelse(bh);
3022 		return true;
3023 	}
3024 	offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
3025 	while (offset < inode->i_size) {
3026 		if (!(offset & (sb->s_blocksize - 1))) {
3027 			unsigned int lblock;
3028 			brelse(bh);
3029 			lblock = offset >> EXT4_BLOCK_SIZE_BITS(sb);
3030 			bh = ext4_read_dirblock(inode, lblock, EITHER);
3031 			if (bh == NULL) {
3032 				offset += sb->s_blocksize;
3033 				continue;
3034 			}
3035 			if (IS_ERR(bh))
3036 				return true;
3037 		}
3038 		de = (struct ext4_dir_entry_2 *) (bh->b_data +
3039 					(offset & (sb->s_blocksize - 1)));
3040 		if (ext4_check_dir_entry(inode, NULL, de, bh,
3041 					 bh->b_data, bh->b_size, offset) ||
3042 		    le32_to_cpu(de->inode)) {
3043 			brelse(bh);
3044 			return false;
3045 		}
3046 		offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
3047 	}
3048 	brelse(bh);
3049 	return true;
3050 }
3051 
3052 /*
3053  * ext4_orphan_add() links an unlinked or truncated inode into a list of
3054  * such inodes, starting at the superblock, in case we crash before the
3055  * file is closed/deleted, or in case the inode truncate spans multiple
3056  * transactions and the last transaction is not recovered after a crash.
3057  *
3058  * At filesystem recovery time, we walk this list deleting unlinked
3059  * inodes and truncating linked inodes in ext4_orphan_cleanup().
3060  *
3061  * Orphan list manipulation functions must be called under i_mutex unless
3062  * we are just creating the inode or deleting it.
3063  */
ext4_orphan_add(handle_t * handle,struct inode * inode)3064 int ext4_orphan_add(handle_t *handle, struct inode *inode)
3065 {
3066 	struct super_block *sb = inode->i_sb;
3067 	struct ext4_sb_info *sbi = EXT4_SB(sb);
3068 	struct ext4_iloc iloc;
3069 	int err = 0, rc;
3070 	bool dirty = false;
3071 
3072 	if (!sbi->s_journal || is_bad_inode(inode))
3073 		return 0;
3074 
3075 	WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
3076 		     !inode_is_locked(inode));
3077 	/*
3078 	 * Exit early if inode already is on orphan list. This is a big speedup
3079 	 * since we don't have to contend on the global s_orphan_lock.
3080 	 */
3081 	if (!list_empty(&EXT4_I(inode)->i_orphan))
3082 		return 0;
3083 
3084 	/*
3085 	 * Orphan handling is only valid for files with data blocks
3086 	 * being truncated, or files being unlinked. Note that we either
3087 	 * hold i_mutex, or the inode can not be referenced from outside,
3088 	 * so i_nlink should not be bumped due to race
3089 	 */
3090 	J_ASSERT((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
3091 		  S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);
3092 
3093 	BUFFER_TRACE(sbi->s_sbh, "get_write_access");
3094 	err = ext4_journal_get_write_access(handle, sbi->s_sbh);
3095 	if (err)
3096 		goto out;
3097 
3098 	err = ext4_reserve_inode_write(handle, inode, &iloc);
3099 	if (err)
3100 		goto out;
3101 
3102 	mutex_lock(&sbi->s_orphan_lock);
3103 	/*
3104 	 * Due to previous errors inode may be already a part of on-disk
3105 	 * orphan list. If so skip on-disk list modification.
3106 	 */
3107 	if (!NEXT_ORPHAN(inode) || NEXT_ORPHAN(inode) >
3108 	    (le32_to_cpu(sbi->s_es->s_inodes_count))) {
3109 		/* Insert this inode at the head of the on-disk orphan list */
3110 		NEXT_ORPHAN(inode) = le32_to_cpu(sbi->s_es->s_last_orphan);
3111 		sbi->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
3112 		dirty = true;
3113 	}
3114 	list_add(&EXT4_I(inode)->i_orphan, &sbi->s_orphan);
3115 	mutex_unlock(&sbi->s_orphan_lock);
3116 
3117 	if (dirty) {
3118 		err = ext4_handle_dirty_super(handle, sb);
3119 		rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
3120 		if (!err)
3121 			err = rc;
3122 		if (err) {
3123 			/*
3124 			 * We have to remove inode from in-memory list if
3125 			 * addition to on disk orphan list failed. Stray orphan
3126 			 * list entries can cause panics at unmount time.
3127 			 */
3128 			mutex_lock(&sbi->s_orphan_lock);
3129 			list_del_init(&EXT4_I(inode)->i_orphan);
3130 			mutex_unlock(&sbi->s_orphan_lock);
3131 		}
3132 	} else
3133 		brelse(iloc.bh);
3134 
3135 	jbd_debug(4, "superblock will point to %lu\n", inode->i_ino);
3136 	jbd_debug(4, "orphan inode %lu will point to %d\n",
3137 			inode->i_ino, NEXT_ORPHAN(inode));
3138 out:
3139 	ext4_std_error(sb, err);
3140 	return err;
3141 }
3142 
3143 /*
3144  * ext4_orphan_del() removes an unlinked or truncated inode from the list
3145  * of such inodes stored on disk, because it is finally being cleaned up.
3146  */
ext4_orphan_del(handle_t * handle,struct inode * inode)3147 int ext4_orphan_del(handle_t *handle, struct inode *inode)
3148 {
3149 	struct list_head *prev;
3150 	struct ext4_inode_info *ei = EXT4_I(inode);
3151 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3152 	__u32 ino_next;
3153 	struct ext4_iloc iloc;
3154 	int err = 0;
3155 
3156 	if (!sbi->s_journal && !(sbi->s_mount_state & EXT4_ORPHAN_FS))
3157 		return 0;
3158 
3159 	WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
3160 		     !inode_is_locked(inode));
3161 	/* Do this quick check before taking global s_orphan_lock. */
3162 	if (list_empty(&ei->i_orphan))
3163 		return 0;
3164 
3165 	if (handle) {
3166 		/* Grab inode buffer early before taking global s_orphan_lock */
3167 		err = ext4_reserve_inode_write(handle, inode, &iloc);
3168 	}
3169 
3170 	mutex_lock(&sbi->s_orphan_lock);
3171 	jbd_debug(4, "remove inode %lu from orphan list\n", inode->i_ino);
3172 
3173 	prev = ei->i_orphan.prev;
3174 	list_del_init(&ei->i_orphan);
3175 
3176 	/* If we're on an error path, we may not have a valid
3177 	 * transaction handle with which to update the orphan list on
3178 	 * disk, but we still need to remove the inode from the linked
3179 	 * list in memory. */
3180 	if (!handle || err) {
3181 		mutex_unlock(&sbi->s_orphan_lock);
3182 		goto out_err;
3183 	}
3184 
3185 	ino_next = NEXT_ORPHAN(inode);
3186 	if (prev == &sbi->s_orphan) {
3187 		jbd_debug(4, "superblock will point to %u\n", ino_next);
3188 		BUFFER_TRACE(sbi->s_sbh, "get_write_access");
3189 		err = ext4_journal_get_write_access(handle, sbi->s_sbh);
3190 		if (err) {
3191 			mutex_unlock(&sbi->s_orphan_lock);
3192 			goto out_brelse;
3193 		}
3194 		sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
3195 		mutex_unlock(&sbi->s_orphan_lock);
3196 		err = ext4_handle_dirty_super(handle, inode->i_sb);
3197 	} else {
3198 		struct ext4_iloc iloc2;
3199 		struct inode *i_prev =
3200 			&list_entry(prev, struct ext4_inode_info, i_orphan)->vfs_inode;
3201 
3202 		jbd_debug(4, "orphan inode %lu will point to %u\n",
3203 			  i_prev->i_ino, ino_next);
3204 		err = ext4_reserve_inode_write(handle, i_prev, &iloc2);
3205 		if (err) {
3206 			mutex_unlock(&sbi->s_orphan_lock);
3207 			goto out_brelse;
3208 		}
3209 		NEXT_ORPHAN(i_prev) = ino_next;
3210 		err = ext4_mark_iloc_dirty(handle, i_prev, &iloc2);
3211 		mutex_unlock(&sbi->s_orphan_lock);
3212 	}
3213 	if (err)
3214 		goto out_brelse;
3215 	NEXT_ORPHAN(inode) = 0;
3216 	err = ext4_mark_iloc_dirty(handle, inode, &iloc);
3217 out_err:
3218 	ext4_std_error(inode->i_sb, err);
3219 	return err;
3220 
3221 out_brelse:
3222 	brelse(iloc.bh);
3223 	goto out_err;
3224 }
3225 
ext4_rmdir(struct inode * dir,struct dentry * dentry)3226 static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
3227 {
3228 	int retval;
3229 	struct inode *inode;
3230 	struct buffer_head *bh;
3231 	struct ext4_dir_entry_2 *de;
3232 	handle_t *handle = NULL;
3233 
3234 	if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
3235 		return -EIO;
3236 
3237 	/* Initialize quotas before so that eventual writes go in
3238 	 * separate transaction */
3239 	retval = dquot_initialize(dir);
3240 	if (retval)
3241 		return retval;
3242 	retval = dquot_initialize(d_inode(dentry));
3243 	if (retval)
3244 		return retval;
3245 
3246 	retval = -ENOENT;
3247 	bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
3248 	if (IS_ERR(bh))
3249 		return PTR_ERR(bh);
3250 	if (!bh)
3251 		goto end_rmdir;
3252 
3253 	inode = d_inode(dentry);
3254 
3255 	retval = -EFSCORRUPTED;
3256 	if (le32_to_cpu(de->inode) != inode->i_ino)
3257 		goto end_rmdir;
3258 
3259 	retval = -ENOTEMPTY;
3260 	if (!ext4_empty_dir(inode))
3261 		goto end_rmdir;
3262 
3263 	handle = ext4_journal_start(dir, EXT4_HT_DIR,
3264 				    EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
3265 	if (IS_ERR(handle)) {
3266 		retval = PTR_ERR(handle);
3267 		handle = NULL;
3268 		goto end_rmdir;
3269 	}
3270 
3271 	if (IS_DIRSYNC(dir))
3272 		ext4_handle_sync(handle);
3273 
3274 	retval = ext4_delete_entry(handle, dir, de, bh);
3275 	if (retval)
3276 		goto end_rmdir;
3277 	if (!EXT4_DIR_LINK_EMPTY(inode))
3278 		ext4_warning_inode(inode,
3279 			     "empty directory '%.*s' has too many links (%u)",
3280 			     dentry->d_name.len, dentry->d_name.name,
3281 			     inode->i_nlink);
3282 	inode_inc_iversion(inode);
3283 	clear_nlink(inode);
3284 	/* There's no need to set i_disksize: the fact that i_nlink is
3285 	 * zero will ensure that the right thing happens during any
3286 	 * recovery. */
3287 	inode->i_size = 0;
3288 	ext4_orphan_add(handle, inode);
3289 	inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
3290 	ext4_mark_inode_dirty(handle, inode);
3291 	ext4_dec_count(handle, dir);
3292 	ext4_update_dx_flag(dir);
3293 	ext4_mark_inode_dirty(handle, dir);
3294 
3295 #ifdef CONFIG_UNICODE
3296 	/* VFS negative dentries are incompatible with Encoding and
3297 	 * Case-insensitiveness. Eventually we'll want avoid
3298 	 * invalidating the dentries here, alongside with returning the
3299 	 * negative dentries at ext4_lookup(), when it is better
3300 	 * supported by the VFS for the CI case.
3301 	 */
3302 	if (IS_CASEFOLDED(dir))
3303 		d_invalidate(dentry);
3304 #endif
3305 
3306 end_rmdir:
3307 	brelse(bh);
3308 	if (handle)
3309 		ext4_journal_stop(handle);
3310 	return retval;
3311 }
3312 
ext4_unlink(struct inode * dir,struct dentry * dentry)3313 static int ext4_unlink(struct inode *dir, struct dentry *dentry)
3314 {
3315 	int retval;
3316 	struct inode *inode;
3317 	struct buffer_head *bh;
3318 	struct ext4_dir_entry_2 *de;
3319 	handle_t *handle = NULL;
3320 
3321 	if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
3322 		return -EIO;
3323 
3324 	trace_ext4_unlink_enter(dir, dentry);
3325 	/* Initialize quotas before so that eventual writes go
3326 	 * in separate transaction */
3327 	retval = dquot_initialize(dir);
3328 	if (retval)
3329 		return retval;
3330 	retval = dquot_initialize(d_inode(dentry));
3331 	if (retval)
3332 		return retval;
3333 
3334 	retval = -ENOENT;
3335 	bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
3336 	if (IS_ERR(bh))
3337 		return PTR_ERR(bh);
3338 	if (!bh)
3339 		goto end_unlink;
3340 
3341 	inode = d_inode(dentry);
3342 
3343 	retval = -EFSCORRUPTED;
3344 	if (le32_to_cpu(de->inode) != inode->i_ino)
3345 		goto end_unlink;
3346 
3347 	handle = ext4_journal_start(dir, EXT4_HT_DIR,
3348 				    EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
3349 	if (IS_ERR(handle)) {
3350 		retval = PTR_ERR(handle);
3351 		handle = NULL;
3352 		goto end_unlink;
3353 	}
3354 
3355 	if (IS_DIRSYNC(dir))
3356 		ext4_handle_sync(handle);
3357 
3358 	retval = ext4_delete_entry(handle, dir, de, bh);
3359 	if (retval)
3360 		goto end_unlink;
3361 	dir->i_ctime = dir->i_mtime = current_time(dir);
3362 	ext4_update_dx_flag(dir);
3363 	ext4_mark_inode_dirty(handle, dir);
3364 	if (inode->i_nlink == 0)
3365 		ext4_warning_inode(inode, "Deleting file '%.*s' with no links",
3366 				   dentry->d_name.len, dentry->d_name.name);
3367 	else
3368 		drop_nlink(inode);
3369 	if (!inode->i_nlink)
3370 		ext4_orphan_add(handle, inode);
3371 	inode->i_ctime = current_time(inode);
3372 	ext4_mark_inode_dirty(handle, inode);
3373 
3374 #ifdef CONFIG_UNICODE
3375 	/* VFS negative dentries are incompatible with Encoding and
3376 	 * Case-insensitiveness. Eventually we'll want avoid
3377 	 * invalidating the dentries here, alongside with returning the
3378 	 * negative dentries at ext4_lookup(), when it is  better
3379 	 * supported by the VFS for the CI case.
3380 	 */
3381 	if (IS_CASEFOLDED(dir))
3382 		d_invalidate(dentry);
3383 #endif
3384 
3385 end_unlink:
3386 	brelse(bh);
3387 	if (handle)
3388 		ext4_journal_stop(handle);
3389 	trace_ext4_unlink_exit(dentry, retval);
3390 	return retval;
3391 }
3392 
ext4_symlink(struct inode * dir,struct dentry * dentry,const char * symname)3393 static int ext4_symlink(struct inode *dir,
3394 			struct dentry *dentry, const char *symname)
3395 {
3396 	handle_t *handle;
3397 	struct inode *inode;
3398 	int err, len = strlen(symname);
3399 	int credits;
3400 	struct fscrypt_str disk_link;
3401 
3402 	if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
3403 		return -EIO;
3404 
3405 	err = fscrypt_prepare_symlink(dir, symname, len, dir->i_sb->s_blocksize,
3406 				      &disk_link);
3407 	if (err)
3408 		return err;
3409 
3410 	err = dquot_initialize(dir);
3411 	if (err)
3412 		return err;
3413 
3414 	if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3415 		/*
3416 		 * For non-fast symlinks, we just allocate inode and put it on
3417 		 * orphan list in the first transaction => we need bitmap,
3418 		 * group descriptor, sb, inode block, quota blocks, and
3419 		 * possibly selinux xattr blocks.
3420 		 */
3421 		credits = 4 + EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
3422 			  EXT4_XATTR_TRANS_BLOCKS;
3423 	} else {
3424 		/*
3425 		 * Fast symlink. We have to add entry to directory
3426 		 * (EXT4_DATA_TRANS_BLOCKS + EXT4_INDEX_EXTRA_TRANS_BLOCKS),
3427 		 * allocate new inode (bitmap, group descriptor, inode block,
3428 		 * quota blocks, sb is already counted in previous macros).
3429 		 */
3430 		credits = EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3431 			  EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3;
3432 	}
3433 
3434 	inode = ext4_new_inode_start_handle(dir, S_IFLNK|S_IRWXUGO,
3435 					    &dentry->d_name, 0, NULL,
3436 					    EXT4_HT_DIR, credits);
3437 	handle = ext4_journal_current_handle();
3438 	if (IS_ERR(inode)) {
3439 		if (handle)
3440 			ext4_journal_stop(handle);
3441 		return PTR_ERR(inode);
3442 	}
3443 
3444 	if (IS_ENCRYPTED(inode)) {
3445 		err = fscrypt_encrypt_symlink(inode, symname, len, &disk_link);
3446 		if (err)
3447 			goto err_drop_inode;
3448 		inode->i_op = &ext4_encrypted_symlink_inode_operations;
3449 	}
3450 
3451 	if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3452 		if (!IS_ENCRYPTED(inode))
3453 			inode->i_op = &ext4_symlink_inode_operations;
3454 		inode_nohighmem(inode);
3455 		ext4_set_aops(inode);
3456 		/*
3457 		 * We cannot call page_symlink() with transaction started
3458 		 * because it calls into ext4_write_begin() which can wait
3459 		 * for transaction commit if we are running out of space
3460 		 * and thus we deadlock. So we have to stop transaction now
3461 		 * and restart it when symlink contents is written.
3462 		 *
3463 		 * To keep fs consistent in case of crash, we have to put inode
3464 		 * to orphan list in the mean time.
3465 		 */
3466 		drop_nlink(inode);
3467 		err = ext4_orphan_add(handle, inode);
3468 		ext4_journal_stop(handle);
3469 		handle = NULL;
3470 		if (err)
3471 			goto err_drop_inode;
3472 		err = __page_symlink(inode, disk_link.name, disk_link.len, 1);
3473 		if (err)
3474 			goto err_drop_inode;
3475 		/*
3476 		 * Now inode is being linked into dir (EXT4_DATA_TRANS_BLOCKS
3477 		 * + EXT4_INDEX_EXTRA_TRANS_BLOCKS), inode is also modified
3478 		 */
3479 		handle = ext4_journal_start(dir, EXT4_HT_DIR,
3480 				EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3481 				EXT4_INDEX_EXTRA_TRANS_BLOCKS + 1);
3482 		if (IS_ERR(handle)) {
3483 			err = PTR_ERR(handle);
3484 			handle = NULL;
3485 			goto err_drop_inode;
3486 		}
3487 		set_nlink(inode, 1);
3488 		err = ext4_orphan_del(handle, inode);
3489 		if (err)
3490 			goto err_drop_inode;
3491 	} else {
3492 		/* clear the extent format for fast symlink */
3493 		ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
3494 		if (!IS_ENCRYPTED(inode)) {
3495 			inode->i_op = &ext4_fast_symlink_inode_operations;
3496 			inode->i_link = (char *)&EXT4_I(inode)->i_data;
3497 		}
3498 		memcpy((char *)&EXT4_I(inode)->i_data, disk_link.name,
3499 		       disk_link.len);
3500 		inode->i_size = disk_link.len - 1;
3501 	}
3502 	EXT4_I(inode)->i_disksize = inode->i_size;
3503 	err = ext4_add_nondir(handle, dentry, inode);
3504 	if (!err && IS_DIRSYNC(dir))
3505 		ext4_handle_sync(handle);
3506 
3507 	if (handle)
3508 		ext4_journal_stop(handle);
3509 	goto out_free_encrypted_link;
3510 
3511 err_drop_inode:
3512 	if (handle)
3513 		ext4_journal_stop(handle);
3514 	clear_nlink(inode);
3515 	unlock_new_inode(inode);
3516 	iput(inode);
3517 out_free_encrypted_link:
3518 	if (disk_link.name != (unsigned char *)symname)
3519 		kfree(disk_link.name);
3520 	return err;
3521 }
3522 
ext4_link(struct dentry * old_dentry,struct inode * dir,struct dentry * dentry)3523 static int ext4_link(struct dentry *old_dentry,
3524 		     struct inode *dir, struct dentry *dentry)
3525 {
3526 	handle_t *handle;
3527 	struct inode *inode = d_inode(old_dentry);
3528 	int err, retries = 0;
3529 
3530 	if (inode->i_nlink >= EXT4_LINK_MAX)
3531 		return -EMLINK;
3532 
3533 	err = fscrypt_prepare_link(old_dentry, dir, dentry);
3534 	if (err)
3535 		return err;
3536 
3537 	if ((ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT)) &&
3538 	    (!projid_eq(EXT4_I(dir)->i_projid,
3539 			EXT4_I(old_dentry->d_inode)->i_projid)))
3540 		return -EXDEV;
3541 
3542 	err = dquot_initialize(dir);
3543 	if (err)
3544 		return err;
3545 
3546 retry:
3547 	handle = ext4_journal_start(dir, EXT4_HT_DIR,
3548 		(EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3549 		 EXT4_INDEX_EXTRA_TRANS_BLOCKS) + 1);
3550 	if (IS_ERR(handle))
3551 		return PTR_ERR(handle);
3552 
3553 	if (IS_DIRSYNC(dir))
3554 		ext4_handle_sync(handle);
3555 
3556 	inode->i_ctime = current_time(inode);
3557 	ext4_inc_count(handle, inode);
3558 	ihold(inode);
3559 
3560 	err = ext4_add_entry(handle, dentry, inode);
3561 	if (!err) {
3562 		ext4_mark_inode_dirty(handle, inode);
3563 		/* this can happen only for tmpfile being
3564 		 * linked the first time
3565 		 */
3566 		if (inode->i_nlink == 1)
3567 			ext4_orphan_del(handle, inode);
3568 		d_instantiate(dentry, inode);
3569 	} else {
3570 		drop_nlink(inode);
3571 		iput(inode);
3572 	}
3573 	ext4_journal_stop(handle);
3574 	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
3575 		goto retry;
3576 	return err;
3577 }
3578 
3579 
3580 /*
3581  * Try to find buffer head where contains the parent block.
3582  * It should be the inode block if it is inlined or the 1st block
3583  * if it is a normal dir.
3584  */
ext4_get_first_dir_block(handle_t * handle,struct inode * inode,int * retval,struct ext4_dir_entry_2 ** parent_de,int * inlined)3585 static struct buffer_head *ext4_get_first_dir_block(handle_t *handle,
3586 					struct inode *inode,
3587 					int *retval,
3588 					struct ext4_dir_entry_2 **parent_de,
3589 					int *inlined)
3590 {
3591 	struct buffer_head *bh;
3592 
3593 	if (!ext4_has_inline_data(inode)) {
3594 		struct ext4_dir_entry_2 *de;
3595 		unsigned int offset;
3596 
3597 		/* The first directory block must not be a hole, so
3598 		 * treat it as DIRENT_HTREE
3599 		 */
3600 		bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE);
3601 		if (IS_ERR(bh)) {
3602 			*retval = PTR_ERR(bh);
3603 			return NULL;
3604 		}
3605 
3606 		de = (struct ext4_dir_entry_2 *) bh->b_data;
3607 		if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data,
3608 					 bh->b_size, 0) ||
3609 		    le32_to_cpu(de->inode) != inode->i_ino ||
3610 		    strcmp(".", de->name)) {
3611 			EXT4_ERROR_INODE(inode, "directory missing '.'");
3612 			brelse(bh);
3613 			*retval = -EFSCORRUPTED;
3614 			return NULL;
3615 		}
3616 		offset = ext4_rec_len_from_disk(de->rec_len,
3617 						inode->i_sb->s_blocksize);
3618 		de = ext4_next_entry(de, inode->i_sb->s_blocksize);
3619 		if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data,
3620 					 bh->b_size, offset) ||
3621 		    le32_to_cpu(de->inode) == 0 || strcmp("..", de->name)) {
3622 			EXT4_ERROR_INODE(inode, "directory missing '..'");
3623 			brelse(bh);
3624 			*retval = -EFSCORRUPTED;
3625 			return NULL;
3626 		}
3627 		*parent_de = de;
3628 
3629 		return bh;
3630 	}
3631 
3632 	*inlined = 1;
3633 	return ext4_get_first_inline_block(inode, parent_de, retval);
3634 }
3635 
3636 struct ext4_renament {
3637 	struct inode *dir;
3638 	struct dentry *dentry;
3639 	struct inode *inode;
3640 	bool is_dir;
3641 	int dir_nlink_delta;
3642 
3643 	/* entry for "dentry" */
3644 	struct buffer_head *bh;
3645 	struct ext4_dir_entry_2 *de;
3646 	int inlined;
3647 
3648 	/* entry for ".." in inode if it's a directory */
3649 	struct buffer_head *dir_bh;
3650 	struct ext4_dir_entry_2 *parent_de;
3651 	int dir_inlined;
3652 };
3653 
ext4_rename_dir_prepare(handle_t * handle,struct ext4_renament * ent)3654 static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent)
3655 {
3656 	int retval;
3657 
3658 	ent->dir_bh = ext4_get_first_dir_block(handle, ent->inode,
3659 					      &retval, &ent->parent_de,
3660 					      &ent->dir_inlined);
3661 	if (!ent->dir_bh)
3662 		return retval;
3663 	if (le32_to_cpu(ent->parent_de->inode) != ent->dir->i_ino)
3664 		return -EFSCORRUPTED;
3665 	BUFFER_TRACE(ent->dir_bh, "get_write_access");
3666 	return ext4_journal_get_write_access(handle, ent->dir_bh);
3667 }
3668 
ext4_rename_dir_finish(handle_t * handle,struct ext4_renament * ent,unsigned dir_ino)3669 static int ext4_rename_dir_finish(handle_t *handle, struct ext4_renament *ent,
3670 				  unsigned dir_ino)
3671 {
3672 	int retval;
3673 
3674 	ent->parent_de->inode = cpu_to_le32(dir_ino);
3675 	BUFFER_TRACE(ent->dir_bh, "call ext4_handle_dirty_metadata");
3676 	if (!ent->dir_inlined) {
3677 		if (is_dx(ent->inode)) {
3678 			retval = ext4_handle_dirty_dx_node(handle,
3679 							   ent->inode,
3680 							   ent->dir_bh);
3681 		} else {
3682 			retval = ext4_handle_dirty_dirblock(handle, ent->inode,
3683 							    ent->dir_bh);
3684 		}
3685 	} else {
3686 		retval = ext4_mark_inode_dirty(handle, ent->inode);
3687 	}
3688 	if (retval) {
3689 		ext4_std_error(ent->dir->i_sb, retval);
3690 		return retval;
3691 	}
3692 	return 0;
3693 }
3694 
ext4_setent(handle_t * handle,struct ext4_renament * ent,unsigned ino,unsigned file_type)3695 static int ext4_setent(handle_t *handle, struct ext4_renament *ent,
3696 		       unsigned ino, unsigned file_type)
3697 {
3698 	int retval;
3699 
3700 	BUFFER_TRACE(ent->bh, "get write access");
3701 	retval = ext4_journal_get_write_access(handle, ent->bh);
3702 	if (retval)
3703 		return retval;
3704 	ent->de->inode = cpu_to_le32(ino);
3705 	if (ext4_has_feature_filetype(ent->dir->i_sb))
3706 		ent->de->file_type = file_type;
3707 	inode_inc_iversion(ent->dir);
3708 	ent->dir->i_ctime = ent->dir->i_mtime =
3709 		current_time(ent->dir);
3710 	ext4_mark_inode_dirty(handle, ent->dir);
3711 	BUFFER_TRACE(ent->bh, "call ext4_handle_dirty_metadata");
3712 	if (!ent->inlined) {
3713 		retval = ext4_handle_dirty_dirblock(handle, ent->dir, ent->bh);
3714 		if (unlikely(retval)) {
3715 			ext4_std_error(ent->dir->i_sb, retval);
3716 			return retval;
3717 		}
3718 	}
3719 
3720 	return 0;
3721 }
3722 
ext4_resetent(handle_t * handle,struct ext4_renament * ent,unsigned ino,unsigned file_type)3723 static void ext4_resetent(handle_t *handle, struct ext4_renament *ent,
3724 			  unsigned ino, unsigned file_type)
3725 {
3726 	struct ext4_renament old = *ent;
3727 	int retval = 0;
3728 
3729 	/*
3730 	 * old->de could have moved from under us during make indexed dir,
3731 	 * so the old->de may no longer valid and need to find it again
3732 	 * before reset old inode info.
3733 	 */
3734 	old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de,
3735 				 &old.inlined);
3736 	if (IS_ERR(old.bh))
3737 		retval = PTR_ERR(old.bh);
3738 	if (!old.bh)
3739 		retval = -ENOENT;
3740 	if (retval) {
3741 		ext4_std_error(old.dir->i_sb, retval);
3742 		return;
3743 	}
3744 
3745 	ext4_setent(handle, &old, ino, file_type);
3746 	brelse(old.bh);
3747 }
3748 
ext4_find_delete_entry(handle_t * handle,struct inode * dir,const struct qstr * d_name)3749 static int ext4_find_delete_entry(handle_t *handle, struct inode *dir,
3750 				  const struct qstr *d_name)
3751 {
3752 	int retval = -ENOENT;
3753 	struct buffer_head *bh;
3754 	struct ext4_dir_entry_2 *de;
3755 
3756 	bh = ext4_find_entry(dir, d_name, &de, NULL);
3757 	if (IS_ERR(bh))
3758 		return PTR_ERR(bh);
3759 	if (bh) {
3760 		retval = ext4_delete_entry(handle, dir, de, bh);
3761 		brelse(bh);
3762 	}
3763 	return retval;
3764 }
3765 
ext4_rename_delete(handle_t * handle,struct ext4_renament * ent,int force_reread)3766 static void ext4_rename_delete(handle_t *handle, struct ext4_renament *ent,
3767 			       int force_reread)
3768 {
3769 	int retval;
3770 	/*
3771 	 * ent->de could have moved from under us during htree split, so make
3772 	 * sure that we are deleting the right entry.  We might also be pointing
3773 	 * to a stale entry in the unused part of ent->bh so just checking inum
3774 	 * and the name isn't enough.
3775 	 */
3776 	if (le32_to_cpu(ent->de->inode) != ent->inode->i_ino ||
3777 	    ent->de->name_len != ent->dentry->d_name.len ||
3778 	    strncmp(ent->de->name, ent->dentry->d_name.name,
3779 		    ent->de->name_len) ||
3780 	    force_reread) {
3781 		retval = ext4_find_delete_entry(handle, ent->dir,
3782 						&ent->dentry->d_name);
3783 	} else {
3784 		retval = ext4_delete_entry(handle, ent->dir, ent->de, ent->bh);
3785 		if (retval == -ENOENT) {
3786 			retval = ext4_find_delete_entry(handle, ent->dir,
3787 							&ent->dentry->d_name);
3788 		}
3789 	}
3790 
3791 	if (retval) {
3792 		ext4_warning_inode(ent->dir,
3793 				   "Deleting old file: nlink %d, error=%d",
3794 				   ent->dir->i_nlink, retval);
3795 	}
3796 }
3797 
ext4_update_dir_count(handle_t * handle,struct ext4_renament * ent)3798 static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
3799 {
3800 	if (ent->dir_nlink_delta) {
3801 		if (ent->dir_nlink_delta == -1)
3802 			ext4_dec_count(handle, ent->dir);
3803 		else
3804 			ext4_inc_count(handle, ent->dir);
3805 		ext4_mark_inode_dirty(handle, ent->dir);
3806 	}
3807 }
3808 
ext4_whiteout_for_rename(struct ext4_renament * ent,int credits,handle_t ** h)3809 static struct inode *ext4_whiteout_for_rename(struct ext4_renament *ent,
3810 					      int credits, handle_t **h)
3811 {
3812 	struct inode *wh;
3813 	handle_t *handle;
3814 	int retries = 0;
3815 
3816 	/*
3817 	 * for inode block, sb block, group summaries,
3818 	 * and inode bitmap
3819 	 */
3820 	credits += (EXT4_MAXQUOTAS_TRANS_BLOCKS(ent->dir->i_sb) +
3821 		    EXT4_XATTR_TRANS_BLOCKS + 4);
3822 retry:
3823 	wh = ext4_new_inode_start_handle(ent->dir, S_IFCHR | WHITEOUT_MODE,
3824 					 &ent->dentry->d_name, 0, NULL,
3825 					 EXT4_HT_DIR, credits);
3826 
3827 	handle = ext4_journal_current_handle();
3828 	if (IS_ERR(wh)) {
3829 		if (handle)
3830 			ext4_journal_stop(handle);
3831 		if (PTR_ERR(wh) == -ENOSPC &&
3832 		    ext4_should_retry_alloc(ent->dir->i_sb, &retries))
3833 			goto retry;
3834 	} else {
3835 		*h = handle;
3836 		init_special_inode(wh, wh->i_mode, WHITEOUT_DEV);
3837 		wh->i_op = &ext4_special_inode_operations;
3838 	}
3839 	return wh;
3840 }
3841 
3842 /*
3843  * Anybody can rename anything with this: the permission checks are left to the
3844  * higher-level routines.
3845  *
3846  * n.b.  old_{dentry,inode) refers to the source dentry/inode
3847  * while new_{dentry,inode) refers to the destination dentry/inode
3848  * This comes from rename(const char *oldpath, const char *newpath)
3849  */
ext4_rename(struct inode * old_dir,struct dentry * old_dentry,struct inode * new_dir,struct dentry * new_dentry,unsigned int flags)3850 static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
3851 		       struct inode *new_dir, struct dentry *new_dentry,
3852 		       unsigned int flags)
3853 {
3854 	handle_t *handle = NULL;
3855 	struct ext4_renament old = {
3856 		.dir = old_dir,
3857 		.dentry = old_dentry,
3858 		.inode = d_inode(old_dentry),
3859 	};
3860 	struct ext4_renament new = {
3861 		.dir = new_dir,
3862 		.dentry = new_dentry,
3863 		.inode = d_inode(new_dentry),
3864 	};
3865 	int force_reread;
3866 	int retval;
3867 	struct inode *whiteout = NULL;
3868 	int credits;
3869 	u8 old_file_type;
3870 
3871 	if (new.inode && new.inode->i_nlink == 0) {
3872 		EXT4_ERROR_INODE(new.inode,
3873 				 "target of rename is already freed");
3874 		return -EFSCORRUPTED;
3875 	}
3876 
3877 	if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT)) &&
3878 	    (!projid_eq(EXT4_I(new_dir)->i_projid,
3879 			EXT4_I(old_dentry->d_inode)->i_projid)))
3880 		return -EXDEV;
3881 
3882 	retval = dquot_initialize(old.dir);
3883 	if (retval)
3884 		return retval;
3885 	retval = dquot_initialize(old.inode);
3886 	if (retval)
3887 		return retval;
3888 	retval = dquot_initialize(new.dir);
3889 	if (retval)
3890 		return retval;
3891 
3892 	/* Initialize quotas before so that eventual writes go
3893 	 * in separate transaction */
3894 	if (new.inode) {
3895 		retval = dquot_initialize(new.inode);
3896 		if (retval)
3897 			return retval;
3898 	}
3899 
3900 	old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de,
3901 				 &old.inlined);
3902 	if (IS_ERR(old.bh))
3903 		return PTR_ERR(old.bh);
3904 
3905 	/*
3906 	 *  Check for inode number is _not_ due to possible IO errors.
3907 	 *  We might rmdir the source, keep it as pwd of some process
3908 	 *  and merrily kill the link to whatever was created under the
3909 	 *  same name. Goodbye sticky bit ;-<
3910 	 */
3911 	retval = -ENOENT;
3912 	if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3913 		goto release_bh;
3914 
3915 	new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3916 				 &new.de, &new.inlined);
3917 	if (IS_ERR(new.bh)) {
3918 		retval = PTR_ERR(new.bh);
3919 		new.bh = NULL;
3920 		goto release_bh;
3921 	}
3922 	if (new.bh) {
3923 		if (!new.inode) {
3924 			brelse(new.bh);
3925 			new.bh = NULL;
3926 		}
3927 	}
3928 	if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC))
3929 		ext4_alloc_da_blocks(old.inode);
3930 
3931 	credits = (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3932 		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2);
3933 	if (!(flags & RENAME_WHITEOUT)) {
3934 		handle = ext4_journal_start(old.dir, EXT4_HT_DIR, credits);
3935 		if (IS_ERR(handle)) {
3936 			retval = PTR_ERR(handle);
3937 			goto release_bh;
3938 		}
3939 	} else {
3940 		whiteout = ext4_whiteout_for_rename(&old, credits, &handle);
3941 		if (IS_ERR(whiteout)) {
3942 			retval = PTR_ERR(whiteout);
3943 			goto release_bh;
3944 		}
3945 	}
3946 
3947 	old_file_type = old.de->file_type;
3948 	if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3949 		ext4_handle_sync(handle);
3950 
3951 	if (S_ISDIR(old.inode->i_mode)) {
3952 		if (new.inode) {
3953 			retval = -ENOTEMPTY;
3954 			if (!ext4_empty_dir(new.inode))
3955 				goto end_rename;
3956 		} else {
3957 			retval = -EMLINK;
3958 			if (new.dir != old.dir && EXT4_DIR_LINK_MAX(new.dir))
3959 				goto end_rename;
3960 		}
3961 		retval = ext4_rename_dir_prepare(handle, &old);
3962 		if (retval)
3963 			goto end_rename;
3964 	}
3965 	/*
3966 	 * If we're renaming a file within an inline_data dir and adding or
3967 	 * setting the new dirent causes a conversion from inline_data to
3968 	 * extents/blockmap, we need to force the dirent delete code to
3969 	 * re-read the directory, or else we end up trying to delete a dirent
3970 	 * from what is now the extent tree root (or a block map).
3971 	 */
3972 	force_reread = (new.dir->i_ino == old.dir->i_ino &&
3973 			ext4_test_inode_flag(new.dir, EXT4_INODE_INLINE_DATA));
3974 
3975 	if (whiteout) {
3976 		/*
3977 		 * Do this before adding a new entry, so the old entry is sure
3978 		 * to be still pointing to the valid old entry.
3979 		 */
3980 		retval = ext4_setent(handle, &old, whiteout->i_ino,
3981 				     EXT4_FT_CHRDEV);
3982 		if (retval)
3983 			goto end_rename;
3984 		ext4_mark_inode_dirty(handle, whiteout);
3985 	}
3986 	if (!new.bh) {
3987 		retval = ext4_add_entry(handle, new.dentry, old.inode);
3988 		if (retval)
3989 			goto end_rename;
3990 	} else {
3991 		retval = ext4_setent(handle, &new,
3992 				     old.inode->i_ino, old_file_type);
3993 		if (retval)
3994 			goto end_rename;
3995 	}
3996 	if (force_reread)
3997 		force_reread = !ext4_test_inode_flag(new.dir,
3998 						     EXT4_INODE_INLINE_DATA);
3999 
4000 	/*
4001 	 * Like most other Unix systems, set the ctime for inodes on a
4002 	 * rename.
4003 	 */
4004 	old.inode->i_ctime = current_time(old.inode);
4005 	ext4_mark_inode_dirty(handle, old.inode);
4006 
4007 	if (!whiteout) {
4008 		/*
4009 		 * ok, that's it
4010 		 */
4011 		ext4_rename_delete(handle, &old, force_reread);
4012 	}
4013 
4014 	if (new.inode) {
4015 		ext4_dec_count(handle, new.inode);
4016 		new.inode->i_ctime = current_time(new.inode);
4017 	}
4018 	old.dir->i_ctime = old.dir->i_mtime = current_time(old.dir);
4019 	ext4_update_dx_flag(old.dir);
4020 	if (old.dir_bh) {
4021 		retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
4022 		if (retval)
4023 			goto end_rename;
4024 
4025 		ext4_dec_count(handle, old.dir);
4026 		if (new.inode) {
4027 			/* checked ext4_empty_dir above, can't have another
4028 			 * parent, ext4_dec_count() won't work for many-linked
4029 			 * dirs */
4030 			clear_nlink(new.inode);
4031 		} else {
4032 			ext4_inc_count(handle, new.dir);
4033 			ext4_update_dx_flag(new.dir);
4034 			ext4_mark_inode_dirty(handle, new.dir);
4035 		}
4036 	}
4037 	ext4_mark_inode_dirty(handle, old.dir);
4038 	if (new.inode) {
4039 		ext4_mark_inode_dirty(handle, new.inode);
4040 		if (!new.inode->i_nlink)
4041 			ext4_orphan_add(handle, new.inode);
4042 	}
4043 	retval = 0;
4044 
4045 end_rename:
4046 	if (whiteout) {
4047 		if (retval) {
4048 			ext4_resetent(handle, &old,
4049 				      old.inode->i_ino, old_file_type);
4050 			drop_nlink(whiteout);
4051 			ext4_orphan_add(handle, whiteout);
4052 		}
4053 		unlock_new_inode(whiteout);
4054 		ext4_journal_stop(handle);
4055 		iput(whiteout);
4056 	} else {
4057 		ext4_journal_stop(handle);
4058 	}
4059 release_bh:
4060 	brelse(old.dir_bh);
4061 	brelse(old.bh);
4062 	brelse(new.bh);
4063 
4064 	return retval;
4065 }
4066 
ext4_cross_rename(struct inode * old_dir,struct dentry * old_dentry,struct inode * new_dir,struct dentry * new_dentry)4067 static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
4068 			     struct inode *new_dir, struct dentry *new_dentry)
4069 {
4070 	handle_t *handle = NULL;
4071 	struct ext4_renament old = {
4072 		.dir = old_dir,
4073 		.dentry = old_dentry,
4074 		.inode = d_inode(old_dentry),
4075 	};
4076 	struct ext4_renament new = {
4077 		.dir = new_dir,
4078 		.dentry = new_dentry,
4079 		.inode = d_inode(new_dentry),
4080 	};
4081 	u8 new_file_type;
4082 	int retval;
4083 	struct timespec64 ctime;
4084 
4085 	if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT) &&
4086 	     !projid_eq(EXT4_I(new_dir)->i_projid,
4087 			EXT4_I(old_dentry->d_inode)->i_projid)) ||
4088 	    (ext4_test_inode_flag(old_dir, EXT4_INODE_PROJINHERIT) &&
4089 	     !projid_eq(EXT4_I(old_dir)->i_projid,
4090 			EXT4_I(new_dentry->d_inode)->i_projid)))
4091 		return -EXDEV;
4092 
4093 	retval = dquot_initialize(old.dir);
4094 	if (retval)
4095 		return retval;
4096 	retval = dquot_initialize(new.dir);
4097 	if (retval)
4098 		return retval;
4099 
4100 	old.bh = ext4_find_entry(old.dir, &old.dentry->d_name,
4101 				 &old.de, &old.inlined);
4102 	if (IS_ERR(old.bh))
4103 		return PTR_ERR(old.bh);
4104 	/*
4105 	 *  Check for inode number is _not_ due to possible IO errors.
4106 	 *  We might rmdir the source, keep it as pwd of some process
4107 	 *  and merrily kill the link to whatever was created under the
4108 	 *  same name. Goodbye sticky bit ;-<
4109 	 */
4110 	retval = -ENOENT;
4111 	if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
4112 		goto end_rename;
4113 
4114 	new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
4115 				 &new.de, &new.inlined);
4116 	if (IS_ERR(new.bh)) {
4117 		retval = PTR_ERR(new.bh);
4118 		new.bh = NULL;
4119 		goto end_rename;
4120 	}
4121 
4122 	/* RENAME_EXCHANGE case: old *and* new must both exist */
4123 	if (!new.bh || le32_to_cpu(new.de->inode) != new.inode->i_ino)
4124 		goto end_rename;
4125 
4126 	handle = ext4_journal_start(old.dir, EXT4_HT_DIR,
4127 		(2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
4128 		 2 * EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));
4129 	if (IS_ERR(handle)) {
4130 		retval = PTR_ERR(handle);
4131 		handle = NULL;
4132 		goto end_rename;
4133 	}
4134 
4135 	if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
4136 		ext4_handle_sync(handle);
4137 
4138 	if (S_ISDIR(old.inode->i_mode)) {
4139 		old.is_dir = true;
4140 		retval = ext4_rename_dir_prepare(handle, &old);
4141 		if (retval)
4142 			goto end_rename;
4143 	}
4144 	if (S_ISDIR(new.inode->i_mode)) {
4145 		new.is_dir = true;
4146 		retval = ext4_rename_dir_prepare(handle, &new);
4147 		if (retval)
4148 			goto end_rename;
4149 	}
4150 
4151 	/*
4152 	 * Other than the special case of overwriting a directory, parents'
4153 	 * nlink only needs to be modified if this is a cross directory rename.
4154 	 */
4155 	if (old.dir != new.dir && old.is_dir != new.is_dir) {
4156 		old.dir_nlink_delta = old.is_dir ? -1 : 1;
4157 		new.dir_nlink_delta = -old.dir_nlink_delta;
4158 		retval = -EMLINK;
4159 		if ((old.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(old.dir)) ||
4160 		    (new.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(new.dir)))
4161 			goto end_rename;
4162 	}
4163 
4164 	new_file_type = new.de->file_type;
4165 	retval = ext4_setent(handle, &new, old.inode->i_ino, old.de->file_type);
4166 	if (retval)
4167 		goto end_rename;
4168 
4169 	retval = ext4_setent(handle, &old, new.inode->i_ino, new_file_type);
4170 	if (retval)
4171 		goto end_rename;
4172 
4173 	/*
4174 	 * Like most other Unix systems, set the ctime for inodes on a
4175 	 * rename.
4176 	 */
4177 	ctime = current_time(old.inode);
4178 	old.inode->i_ctime = ctime;
4179 	new.inode->i_ctime = ctime;
4180 	ext4_mark_inode_dirty(handle, old.inode);
4181 	ext4_mark_inode_dirty(handle, new.inode);
4182 
4183 	if (old.dir_bh) {
4184 		retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
4185 		if (retval)
4186 			goto end_rename;
4187 	}
4188 	if (new.dir_bh) {
4189 		retval = ext4_rename_dir_finish(handle, &new, old.dir->i_ino);
4190 		if (retval)
4191 			goto end_rename;
4192 	}
4193 	ext4_update_dir_count(handle, &old);
4194 	ext4_update_dir_count(handle, &new);
4195 	retval = 0;
4196 
4197 end_rename:
4198 	brelse(old.dir_bh);
4199 	brelse(new.dir_bh);
4200 	brelse(old.bh);
4201 	brelse(new.bh);
4202 	if (handle)
4203 		ext4_journal_stop(handle);
4204 	return retval;
4205 }
4206 
ext4_rename2(struct inode * old_dir,struct dentry * old_dentry,struct inode * new_dir,struct dentry * new_dentry,unsigned int flags)4207 static int ext4_rename2(struct inode *old_dir, struct dentry *old_dentry,
4208 			struct inode *new_dir, struct dentry *new_dentry,
4209 			unsigned int flags)
4210 {
4211 	int err;
4212 
4213 	if (unlikely(ext4_forced_shutdown(EXT4_SB(old_dir->i_sb))))
4214 		return -EIO;
4215 
4216 	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
4217 		return -EINVAL;
4218 
4219 	err = fscrypt_prepare_rename(old_dir, old_dentry, new_dir, new_dentry,
4220 				     flags);
4221 	if (err)
4222 		return err;
4223 
4224 	if (flags & RENAME_EXCHANGE) {
4225 		return ext4_cross_rename(old_dir, old_dentry,
4226 					 new_dir, new_dentry);
4227 	}
4228 
4229 	return ext4_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
4230 }
4231 
4232 /*
4233  * directories can handle most operations...
4234  */
4235 const struct inode_operations ext4_dir_inode_operations = {
4236 	.create		= ext4_create,
4237 	.lookup		= ext4_lookup,
4238 	.link		= ext4_link,
4239 	.unlink		= ext4_unlink,
4240 	.symlink	= ext4_symlink,
4241 	.mkdir		= ext4_mkdir,
4242 	.rmdir		= ext4_rmdir,
4243 	.mknod		= ext4_mknod,
4244 	.tmpfile	= ext4_tmpfile,
4245 	.rename		= ext4_rename2,
4246 	.setattr	= ext4_setattr,
4247 	.getattr	= ext4_getattr,
4248 	.listxattr	= ext4_listxattr,
4249 	.get_acl	= ext4_get_acl,
4250 	.set_acl	= ext4_set_acl,
4251 	.fiemap         = ext4_fiemap,
4252 };
4253 
4254 const struct inode_operations ext4_special_inode_operations = {
4255 	.setattr	= ext4_setattr,
4256 	.getattr	= ext4_getattr,
4257 	.listxattr	= ext4_listxattr,
4258 	.get_acl	= ext4_get_acl,
4259 	.set_acl	= ext4_set_acl,
4260 };
4261