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1/*
2 * linux/fs/ext4/dir.c
3 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 *
9 * from
10 *
11 * linux/fs/minix/dir.c
12 *
13 * Copyright (C) 1991, 1992 Linus Torvalds
14 *
15 * ext4 directory handling functions
16 *
17 * Big-endian to little-endian byte-swapping/bitmaps by
18 * David S. Miller (davem@caip.rutgers.edu), 1995
19 *
20 * Hash Tree Directory indexing (c) 2001 Daniel Phillips
21 *
22 */
23
24#include <linux/fs.h>
25#include <linux/jbd2.h>
26#include <linux/buffer_head.h>
27#include <linux/slab.h>
28#include <linux/rbtree.h>
29#include "ext4.h"
30
31static unsigned char ext4_filetype_table[] = {
32 DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
33};
34
35static int ext4_readdir(struct file *, void *, filldir_t);
36static int ext4_dx_readdir(struct file *filp,
37 void *dirent, filldir_t filldir);
38static int ext4_release_dir(struct inode *inode,
39 struct file *filp);
40
41const struct file_operations ext4_dir_operations = {
42 .llseek = ext4_llseek,
43 .read = generic_read_dir,
44 .readdir = ext4_readdir, /* we take BKL. needed?*/
45 .unlocked_ioctl = ext4_ioctl,
46#ifdef CONFIG_COMPAT
47 .compat_ioctl = ext4_compat_ioctl,
48#endif
49 .fsync = ext4_sync_file,
50 .release = ext4_release_dir,
51};
52
53
54static unsigned char get_dtype(struct super_block *sb, int filetype)
55{
56 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FILETYPE) ||
57 (filetype >= EXT4_FT_MAX))
58 return DT_UNKNOWN;
59
60 return (ext4_filetype_table[filetype]);
61}
62
63/*
64 * Return 0 if the directory entry is OK, and 1 if there is a problem
65 *
66 * Note: this is the opposite of what ext2 and ext3 historically returned...
67 */
68int __ext4_check_dir_entry(const char *function, unsigned int line,
69 struct inode *dir, struct file *filp,
70 struct ext4_dir_entry_2 *de,
71 struct buffer_head *bh,
72 unsigned int offset)
73{
74 const char *error_msg = NULL;
75 const int rlen = ext4_rec_len_from_disk(de->rec_len,
76 dir->i_sb->s_blocksize);
77
78 if (unlikely(rlen < EXT4_DIR_REC_LEN(1)))
79 error_msg = "rec_len is smaller than minimal";
80 else if (unlikely(rlen % 4 != 0))
81 error_msg = "rec_len % 4 != 0";
82 else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len)))
83 error_msg = "rec_len is too small for name_len";
84 else if (unlikely(((char *) de - bh->b_data) + rlen >
85 dir->i_sb->s_blocksize))
86 error_msg = "directory entry across blocks";
87 else if (unlikely(le32_to_cpu(de->inode) >
88 le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
89 error_msg = "inode out of bounds";
90 else
91 return 0;
92
93 if (filp)
94 ext4_error_file(filp, function, line, bh ? bh->b_blocknr : 0,
95 "bad entry in directory: %s - offset=%u(%u), "
96 "inode=%u, rec_len=%d, name_len=%d",
97 error_msg, (unsigned) (offset%bh->b_size),
98 offset, le32_to_cpu(de->inode),
99 rlen, de->name_len);
100 else
101 ext4_error_inode(dir, function, line, bh ? bh->b_blocknr : 0,
102 "bad entry in directory: %s - offset=%u(%u), "
103 "inode=%u, rec_len=%d, name_len=%d",
104 error_msg, (unsigned) (offset%bh->b_size),
105 offset, le32_to_cpu(de->inode),
106 rlen, de->name_len);
107
108 return 1;
109}
110
111static int ext4_readdir(struct file *filp,
112 void *dirent, filldir_t filldir)
113{
114 int error = 0;
115 unsigned int offset;
116 int i, stored;
117 struct ext4_dir_entry_2 *de;
118 struct super_block *sb;
119 int err;
120 struct inode *inode = filp->f_path.dentry->d_inode;
121 int ret = 0;
122 int dir_has_error = 0;
123
124 sb = inode->i_sb;
125
126 if (EXT4_HAS_COMPAT_FEATURE(inode->i_sb,
127 EXT4_FEATURE_COMPAT_DIR_INDEX) &&
128 ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
129 ((inode->i_size >> sb->s_blocksize_bits) == 1))) {
130 err = ext4_dx_readdir(filp, dirent, filldir);
131 if (err != ERR_BAD_DX_DIR) {
132 ret = err;
133 goto out;
134 }
135 /*
136 * We don't set the inode dirty flag since it's not
137 * critical that it get flushed back to the disk.
138 */
139 ext4_clear_inode_flag(filp->f_path.dentry->d_inode,
140 EXT4_INODE_INDEX);
141 }
142 stored = 0;
143 offset = filp->f_pos & (sb->s_blocksize - 1);
144
145 while (!error && !stored && filp->f_pos < inode->i_size) {
146 struct ext4_map_blocks map;
147 struct buffer_head *bh = NULL;
148
149 map.m_lblk = filp->f_pos >> EXT4_BLOCK_SIZE_BITS(sb);
150 map.m_len = 1;
151 err = ext4_map_blocks(NULL, inode, &map, 0);
152 if (err > 0) {
153 pgoff_t index = map.m_pblk >>
154 (PAGE_CACHE_SHIFT - inode->i_blkbits);
155 if (!ra_has_index(&filp->f_ra, index))
156 page_cache_sync_readahead(
157 sb->s_bdev->bd_inode->i_mapping,
158 &filp->f_ra, filp,
159 index, 1);
160 filp->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT;
161 bh = ext4_bread(NULL, inode, map.m_lblk, 0, &err);
162 }
163
164 /*
165 * We ignore I/O errors on directories so users have a chance
166 * of recovering data when there's a bad sector
167 */
168 if (!bh) {
169 if (!dir_has_error) {
170 EXT4_ERROR_FILE(filp, 0,
171 "directory contains a "
172 "hole at offset %llu",
173 (unsigned long long) filp->f_pos);
174 dir_has_error = 1;
175 }
176 /* corrupt size? Maybe no more blocks to read */
177 if (filp->f_pos > inode->i_blocks << 9)
178 break;
179 filp->f_pos += sb->s_blocksize - offset;
180 continue;
181 }
182
183revalidate:
184 /* If the dir block has changed since the last call to
185 * readdir(2), then we might be pointing to an invalid
186 * dirent right now. Scan from the start of the block
187 * to make sure. */
188 if (filp->f_version != inode->i_version) {
189 for (i = 0; i < sb->s_blocksize && i < offset; ) {
190 de = (struct ext4_dir_entry_2 *)
191 (bh->b_data + i);
192 /* It's too expensive to do a full
193 * dirent test each time round this
194 * loop, but we do have to test at
195 * least that it is non-zero. A
196 * failure will be detected in the
197 * dirent test below. */
198 if (ext4_rec_len_from_disk(de->rec_len,
199 sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
200 break;
201 i += ext4_rec_len_from_disk(de->rec_len,
202 sb->s_blocksize);
203 }
204 offset = i;
205 filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
206 | offset;
207 filp->f_version = inode->i_version;
208 }
209
210 while (!error && filp->f_pos < inode->i_size
211 && offset < sb->s_blocksize) {
212 de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
213 if (ext4_check_dir_entry(inode, filp, de,
214 bh, offset)) {
215 /*
216 * On error, skip the f_pos to the next block
217 */
218 filp->f_pos = (filp->f_pos |
219 (sb->s_blocksize - 1)) + 1;
220 brelse(bh);
221 ret = stored;
222 goto out;
223 }
224 offset += ext4_rec_len_from_disk(de->rec_len,
225 sb->s_blocksize);
226 if (le32_to_cpu(de->inode)) {
227 /* We might block in the next section
228 * if the data destination is
229 * currently swapped out. So, use a
230 * version stamp to detect whether or
231 * not the directory has been modified
232 * during the copy operation.
233 */
234 u64 version = filp->f_version;
235
236 error = filldir(dirent, de->name,
237 de->name_len,
238 filp->f_pos,
239 le32_to_cpu(de->inode),
240 get_dtype(sb, de->file_type));
241 if (error)
242 break;
243 if (version != filp->f_version)
244 goto revalidate;
245 stored++;
246 }
247 filp->f_pos += ext4_rec_len_from_disk(de->rec_len,
248 sb->s_blocksize);
249 }
250 offset = 0;
251 brelse(bh);
252 }
253out:
254 return ret;
255}
256
257/*
258 * These functions convert from the major/minor hash to an f_pos
259 * value.
260 *
261 * Currently we only use major hash numer. This is unfortunate, but
262 * on 32-bit machines, the same VFS interface is used for lseek and
263 * llseek, so if we use the 64 bit offset, then the 32-bit versions of
264 * lseek/telldir/seekdir will blow out spectacularly, and from within
265 * the ext2 low-level routine, we don't know if we're being called by
266 * a 64-bit version of the system call or the 32-bit version of the
267 * system call. Worse yet, NFSv2 only allows for a 32-bit readdir
268 * cookie. Sigh.
269 */
270#define hash2pos(major, minor) (major >> 1)
271#define pos2maj_hash(pos) ((pos << 1) & 0xffffffff)
272#define pos2min_hash(pos) (0)
273
274/*
275 * This structure holds the nodes of the red-black tree used to store
276 * the directory entry in hash order.
277 */
278struct fname {
279 __u32 hash;
280 __u32 minor_hash;
281 struct rb_node rb_hash;
282 struct fname *next;
283 __u32 inode;
284 __u8 name_len;
285 __u8 file_type;
286 char name[0];
287};
288
289/*
290 * This functoin implements a non-recursive way of freeing all of the
291 * nodes in the red-black tree.
292 */
293static void free_rb_tree_fname(struct rb_root *root)
294{
295 struct rb_node *n = root->rb_node;
296 struct rb_node *parent;
297 struct fname *fname;
298
299 while (n) {
300 /* Do the node's children first */
301 if (n->rb_left) {
302 n = n->rb_left;
303 continue;
304 }
305 if (n->rb_right) {
306 n = n->rb_right;
307 continue;
308 }
309 /*
310 * The node has no children; free it, and then zero
311 * out parent's link to it. Finally go to the
312 * beginning of the loop and try to free the parent
313 * node.
314 */
315 parent = rb_parent(n);
316 fname = rb_entry(n, struct fname, rb_hash);
317 while (fname) {
318 struct fname *old = fname;
319 fname = fname->next;
320 kfree(old);
321 }
322 if (!parent)
323 *root = RB_ROOT;
324 else if (parent->rb_left == n)
325 parent->rb_left = NULL;
326 else if (parent->rb_right == n)
327 parent->rb_right = NULL;
328 n = parent;
329 }
330}
331
332
333static struct dir_private_info *ext4_htree_create_dir_info(loff_t pos)
334{
335 struct dir_private_info *p;
336
337 p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
338 if (!p)
339 return NULL;
340 p->curr_hash = pos2maj_hash(pos);
341 p->curr_minor_hash = pos2min_hash(pos);
342 return p;
343}
344
345void ext4_htree_free_dir_info(struct dir_private_info *p)
346{
347 free_rb_tree_fname(&p->root);
348 kfree(p);
349}
350
351/*
352 * Given a directory entry, enter it into the fname rb tree.
353 */
354int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
355 __u32 minor_hash,
356 struct ext4_dir_entry_2 *dirent)
357{
358 struct rb_node **p, *parent = NULL;
359 struct fname *fname, *new_fn;
360 struct dir_private_info *info;
361 int len;
362
363 info = dir_file->private_data;
364 p = &info->root.rb_node;
365
366 /* Create and allocate the fname structure */
367 len = sizeof(struct fname) + dirent->name_len + 1;
368 new_fn = kzalloc(len, GFP_KERNEL);
369 if (!new_fn)
370 return -ENOMEM;
371 new_fn->hash = hash;
372 new_fn->minor_hash = minor_hash;
373 new_fn->inode = le32_to_cpu(dirent->inode);
374 new_fn->name_len = dirent->name_len;
375 new_fn->file_type = dirent->file_type;
376 memcpy(new_fn->name, dirent->name, dirent->name_len);
377 new_fn->name[dirent->name_len] = 0;
378
379 while (*p) {
380 parent = *p;
381 fname = rb_entry(parent, struct fname, rb_hash);
382
383 /*
384 * If the hash and minor hash match up, then we put
385 * them on a linked list. This rarely happens...
386 */
387 if ((new_fn->hash == fname->hash) &&
388 (new_fn->minor_hash == fname->minor_hash)) {
389 new_fn->next = fname->next;
390 fname->next = new_fn;
391 return 0;
392 }
393
394 if (new_fn->hash < fname->hash)
395 p = &(*p)->rb_left;
396 else if (new_fn->hash > fname->hash)
397 p = &(*p)->rb_right;
398 else if (new_fn->minor_hash < fname->minor_hash)
399 p = &(*p)->rb_left;
400 else /* if (new_fn->minor_hash > fname->minor_hash) */
401 p = &(*p)->rb_right;
402 }
403
404 rb_link_node(&new_fn->rb_hash, parent, p);
405 rb_insert_color(&new_fn->rb_hash, &info->root);
406 return 0;
407}
408
409
410
411/*
412 * This is a helper function for ext4_dx_readdir. It calls filldir
413 * for all entres on the fname linked list. (Normally there is only
414 * one entry on the linked list, unless there are 62 bit hash collisions.)
415 */
416static int call_filldir(struct file *filp, void *dirent,
417 filldir_t filldir, struct fname *fname)
418{
419 struct dir_private_info *info = filp->private_data;
420 loff_t curr_pos;
421 struct inode *inode = filp->f_path.dentry->d_inode;
422 struct super_block *sb;
423 int error;
424
425 sb = inode->i_sb;
426
427 if (!fname) {
428 printk(KERN_ERR "EXT4-fs: call_filldir: called with "
429 "null fname?!?\n");
430 return 0;
431 }
432 curr_pos = hash2pos(fname->hash, fname->minor_hash);
433 while (fname) {
434 error = filldir(dirent, fname->name,
435 fname->name_len, curr_pos,
436 fname->inode,
437 get_dtype(sb, fname->file_type));
438 if (error) {
439 filp->f_pos = curr_pos;
440 info->extra_fname = fname;
441 return error;
442 }
443 fname = fname->next;
444 }
445 return 0;
446}
447
448static int ext4_dx_readdir(struct file *filp,
449 void *dirent, filldir_t filldir)
450{
451 struct dir_private_info *info = filp->private_data;
452 struct inode *inode = filp->f_path.dentry->d_inode;
453 struct fname *fname;
454 int ret;
455
456 if (!info) {
457 info = ext4_htree_create_dir_info(filp->f_pos);
458 if (!info)
459 return -ENOMEM;
460 filp->private_data = info;
461 }
462
463 if (filp->f_pos == EXT4_HTREE_EOF)
464 return 0; /* EOF */
465
466 /* Some one has messed with f_pos; reset the world */
467 if (info->last_pos != filp->f_pos) {
468 free_rb_tree_fname(&info->root);
469 info->curr_node = NULL;
470 info->extra_fname = NULL;
471 info->curr_hash = pos2maj_hash(filp->f_pos);
472 info->curr_minor_hash = pos2min_hash(filp->f_pos);
473 }
474
475 /*
476 * If there are any leftover names on the hash collision
477 * chain, return them first.
478 */
479 if (info->extra_fname) {
480 if (call_filldir(filp, dirent, filldir, info->extra_fname))
481 goto finished;
482 info->extra_fname = NULL;
483 goto next_node;
484 } else if (!info->curr_node)
485 info->curr_node = rb_first(&info->root);
486
487 while (1) {
488 /*
489 * Fill the rbtree if we have no more entries,
490 * or the inode has changed since we last read in the
491 * cached entries.
492 */
493 if ((!info->curr_node) ||
494 (filp->f_version != inode->i_version)) {
495 info->curr_node = NULL;
496 free_rb_tree_fname(&info->root);
497 filp->f_version = inode->i_version;
498 ret = ext4_htree_fill_tree(filp, info->curr_hash,
499 info->curr_minor_hash,
500 &info->next_hash);
501 if (ret < 0)
502 return ret;
503 if (ret == 0) {
504 filp->f_pos = EXT4_HTREE_EOF;
505 break;
506 }
507 info->curr_node = rb_first(&info->root);
508 }
509
510 fname = rb_entry(info->curr_node, struct fname, rb_hash);
511 info->curr_hash = fname->hash;
512 info->curr_minor_hash = fname->minor_hash;
513 if (call_filldir(filp, dirent, filldir, fname))
514 break;
515 next_node:
516 info->curr_node = rb_next(info->curr_node);
517 if (info->curr_node) {
518 fname = rb_entry(info->curr_node, struct fname,
519 rb_hash);
520 info->curr_hash = fname->hash;
521 info->curr_minor_hash = fname->minor_hash;
522 } else {
523 if (info->next_hash == ~0) {
524 filp->f_pos = EXT4_HTREE_EOF;
525 break;
526 }
527 info->curr_hash = info->next_hash;
528 info->curr_minor_hash = 0;
529 }
530 }
531finished:
532 info->last_pos = filp->f_pos;
533 return 0;
534}
535
536static int ext4_release_dir(struct inode *inode, struct file *filp)
537{
538 if (filp->private_data)
539 ext4_htree_free_dir_info(filp->private_data);
540
541 return 0;
542}
1/*
2 * linux/fs/ext4/dir.c
3 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 *
9 * from
10 *
11 * linux/fs/minix/dir.c
12 *
13 * Copyright (C) 1991, 1992 Linus Torvalds
14 *
15 * ext4 directory handling functions
16 *
17 * Big-endian to little-endian byte-swapping/bitmaps by
18 * David S. Miller (davem@caip.rutgers.edu), 1995
19 *
20 * Hash Tree Directory indexing (c) 2001 Daniel Phillips
21 *
22 */
23
24#include <linux/fs.h>
25#include <linux/buffer_head.h>
26#include <linux/slab.h>
27#include "ext4.h"
28#include "xattr.h"
29
30static int ext4_dx_readdir(struct file *, struct dir_context *);
31
32/**
33 * Check if the given dir-inode refers to an htree-indexed directory
34 * (or a directory which could potentially get converted to use htree
35 * indexing).
36 *
37 * Return 1 if it is a dx dir, 0 if not
38 */
39static int is_dx_dir(struct inode *inode)
40{
41 struct super_block *sb = inode->i_sb;
42
43 if (ext4_has_feature_dir_index(inode->i_sb) &&
44 ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
45 ((inode->i_size >> sb->s_blocksize_bits) == 1) ||
46 ext4_has_inline_data(inode)))
47 return 1;
48
49 return 0;
50}
51
52/*
53 * Return 0 if the directory entry is OK, and 1 if there is a problem
54 *
55 * Note: this is the opposite of what ext2 and ext3 historically returned...
56 *
57 * bh passed here can be an inode block or a dir data block, depending
58 * on the inode inline data flag.
59 */
60int __ext4_check_dir_entry(const char *function, unsigned int line,
61 struct inode *dir, struct file *filp,
62 struct ext4_dir_entry_2 *de,
63 struct buffer_head *bh, char *buf, int size,
64 unsigned int offset)
65{
66 const char *error_msg = NULL;
67 const int rlen = ext4_rec_len_from_disk(de->rec_len,
68 dir->i_sb->s_blocksize);
69
70 if (unlikely(rlen < EXT4_DIR_REC_LEN(1)))
71 error_msg = "rec_len is smaller than minimal";
72 else if (unlikely(rlen % 4 != 0))
73 error_msg = "rec_len % 4 != 0";
74 else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len)))
75 error_msg = "rec_len is too small for name_len";
76 else if (unlikely(((char *) de - buf) + rlen > size))
77 error_msg = "directory entry across range";
78 else if (unlikely(le32_to_cpu(de->inode) >
79 le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
80 error_msg = "inode out of bounds";
81 else
82 return 0;
83
84 if (filp)
85 ext4_error_file(filp, function, line, bh->b_blocknr,
86 "bad entry in directory: %s - offset=%u(%u), "
87 "inode=%u, rec_len=%d, name_len=%d",
88 error_msg, (unsigned) (offset % size),
89 offset, le32_to_cpu(de->inode),
90 rlen, de->name_len);
91 else
92 ext4_error_inode(dir, function, line, bh->b_blocknr,
93 "bad entry in directory: %s - offset=%u(%u), "
94 "inode=%u, rec_len=%d, name_len=%d",
95 error_msg, (unsigned) (offset % size),
96 offset, le32_to_cpu(de->inode),
97 rlen, de->name_len);
98
99 return 1;
100}
101
102static int ext4_readdir(struct file *file, struct dir_context *ctx)
103{
104 unsigned int offset;
105 int i;
106 struct ext4_dir_entry_2 *de;
107 int err;
108 struct inode *inode = file_inode(file);
109 struct super_block *sb = inode->i_sb;
110 struct buffer_head *bh = NULL;
111 int dir_has_error = 0;
112 struct ext4_str fname_crypto_str = {.name = NULL, .len = 0};
113
114 if (ext4_encrypted_inode(inode)) {
115 err = ext4_get_encryption_info(inode);
116 if (err && err != -ENOKEY)
117 return err;
118 }
119
120 if (is_dx_dir(inode)) {
121 err = ext4_dx_readdir(file, ctx);
122 if (err != ERR_BAD_DX_DIR) {
123 return err;
124 }
125 /*
126 * We don't set the inode dirty flag since it's not
127 * critical that it get flushed back to the disk.
128 */
129 ext4_clear_inode_flag(file_inode(file),
130 EXT4_INODE_INDEX);
131 }
132
133 if (ext4_has_inline_data(inode)) {
134 int has_inline_data = 1;
135 err = ext4_read_inline_dir(file, ctx,
136 &has_inline_data);
137 if (has_inline_data)
138 return err;
139 }
140
141 if (ext4_encrypted_inode(inode)) {
142 err = ext4_fname_crypto_alloc_buffer(inode, EXT4_NAME_LEN,
143 &fname_crypto_str);
144 if (err < 0)
145 return err;
146 }
147
148 offset = ctx->pos & (sb->s_blocksize - 1);
149
150 while (ctx->pos < inode->i_size) {
151 struct ext4_map_blocks map;
152
153 map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb);
154 map.m_len = 1;
155 err = ext4_map_blocks(NULL, inode, &map, 0);
156 if (err > 0) {
157 pgoff_t index = map.m_pblk >>
158 (PAGE_SHIFT - inode->i_blkbits);
159 if (!ra_has_index(&file->f_ra, index))
160 page_cache_sync_readahead(
161 sb->s_bdev->bd_inode->i_mapping,
162 &file->f_ra, file,
163 index, 1);
164 file->f_ra.prev_pos = (loff_t)index << PAGE_SHIFT;
165 bh = ext4_bread(NULL, inode, map.m_lblk, 0);
166 if (IS_ERR(bh)) {
167 err = PTR_ERR(bh);
168 bh = NULL;
169 goto errout;
170 }
171 }
172
173 if (!bh) {
174 if (!dir_has_error) {
175 EXT4_ERROR_FILE(file, 0,
176 "directory contains a "
177 "hole at offset %llu",
178 (unsigned long long) ctx->pos);
179 dir_has_error = 1;
180 }
181 /* corrupt size? Maybe no more blocks to read */
182 if (ctx->pos > inode->i_blocks << 9)
183 break;
184 ctx->pos += sb->s_blocksize - offset;
185 continue;
186 }
187
188 /* Check the checksum */
189 if (!buffer_verified(bh) &&
190 !ext4_dirent_csum_verify(inode,
191 (struct ext4_dir_entry *)bh->b_data)) {
192 EXT4_ERROR_FILE(file, 0, "directory fails checksum "
193 "at offset %llu",
194 (unsigned long long)ctx->pos);
195 ctx->pos += sb->s_blocksize - offset;
196 brelse(bh);
197 bh = NULL;
198 continue;
199 }
200 set_buffer_verified(bh);
201
202 /* If the dir block has changed since the last call to
203 * readdir(2), then we might be pointing to an invalid
204 * dirent right now. Scan from the start of the block
205 * to make sure. */
206 if (file->f_version != inode->i_version) {
207 for (i = 0; i < sb->s_blocksize && i < offset; ) {
208 de = (struct ext4_dir_entry_2 *)
209 (bh->b_data + i);
210 /* It's too expensive to do a full
211 * dirent test each time round this
212 * loop, but we do have to test at
213 * least that it is non-zero. A
214 * failure will be detected in the
215 * dirent test below. */
216 if (ext4_rec_len_from_disk(de->rec_len,
217 sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
218 break;
219 i += ext4_rec_len_from_disk(de->rec_len,
220 sb->s_blocksize);
221 }
222 offset = i;
223 ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
224 | offset;
225 file->f_version = inode->i_version;
226 }
227
228 while (ctx->pos < inode->i_size
229 && offset < sb->s_blocksize) {
230 de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
231 if (ext4_check_dir_entry(inode, file, de, bh,
232 bh->b_data, bh->b_size,
233 offset)) {
234 /*
235 * On error, skip to the next block
236 */
237 ctx->pos = (ctx->pos |
238 (sb->s_blocksize - 1)) + 1;
239 break;
240 }
241 offset += ext4_rec_len_from_disk(de->rec_len,
242 sb->s_blocksize);
243 if (le32_to_cpu(de->inode)) {
244 if (!ext4_encrypted_inode(inode)) {
245 if (!dir_emit(ctx, de->name,
246 de->name_len,
247 le32_to_cpu(de->inode),
248 get_dtype(sb, de->file_type)))
249 goto done;
250 } else {
251 int save_len = fname_crypto_str.len;
252
253 /* Directory is encrypted */
254 err = ext4_fname_disk_to_usr(inode,
255 NULL, de, &fname_crypto_str);
256 fname_crypto_str.len = save_len;
257 if (err < 0)
258 goto errout;
259 if (!dir_emit(ctx,
260 fname_crypto_str.name, err,
261 le32_to_cpu(de->inode),
262 get_dtype(sb, de->file_type)))
263 goto done;
264 }
265 }
266 ctx->pos += ext4_rec_len_from_disk(de->rec_len,
267 sb->s_blocksize);
268 }
269 if ((ctx->pos < inode->i_size) && !dir_relax(inode))
270 goto done;
271 brelse(bh);
272 bh = NULL;
273 offset = 0;
274 }
275done:
276 err = 0;
277errout:
278#ifdef CONFIG_EXT4_FS_ENCRYPTION
279 ext4_fname_crypto_free_buffer(&fname_crypto_str);
280#endif
281 brelse(bh);
282 return err;
283}
284
285static inline int is_32bit_api(void)
286{
287#ifdef CONFIG_COMPAT
288 return in_compat_syscall();
289#else
290 return (BITS_PER_LONG == 32);
291#endif
292}
293
294/*
295 * These functions convert from the major/minor hash to an f_pos
296 * value for dx directories
297 *
298 * Upper layer (for example NFS) should specify FMODE_32BITHASH or
299 * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
300 * directly on both 32-bit and 64-bit nodes, under such case, neither
301 * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
302 */
303static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
304{
305 if ((filp->f_mode & FMODE_32BITHASH) ||
306 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
307 return major >> 1;
308 else
309 return ((__u64)(major >> 1) << 32) | (__u64)minor;
310}
311
312static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
313{
314 if ((filp->f_mode & FMODE_32BITHASH) ||
315 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
316 return (pos << 1) & 0xffffffff;
317 else
318 return ((pos >> 32) << 1) & 0xffffffff;
319}
320
321static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
322{
323 if ((filp->f_mode & FMODE_32BITHASH) ||
324 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
325 return 0;
326 else
327 return pos & 0xffffffff;
328}
329
330/*
331 * Return 32- or 64-bit end-of-file for dx directories
332 */
333static inline loff_t ext4_get_htree_eof(struct file *filp)
334{
335 if ((filp->f_mode & FMODE_32BITHASH) ||
336 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
337 return EXT4_HTREE_EOF_32BIT;
338 else
339 return EXT4_HTREE_EOF_64BIT;
340}
341
342
343/*
344 * ext4_dir_llseek() calls generic_file_llseek_size to handle htree
345 * directories, where the "offset" is in terms of the filename hash
346 * value instead of the byte offset.
347 *
348 * Because we may return a 64-bit hash that is well beyond offset limits,
349 * we need to pass the max hash as the maximum allowable offset in
350 * the htree directory case.
351 *
352 * For non-htree, ext4_llseek already chooses the proper max offset.
353 */
354static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence)
355{
356 struct inode *inode = file->f_mapping->host;
357 int dx_dir = is_dx_dir(inode);
358 loff_t htree_max = ext4_get_htree_eof(file);
359
360 if (likely(dx_dir))
361 return generic_file_llseek_size(file, offset, whence,
362 htree_max, htree_max);
363 else
364 return ext4_llseek(file, offset, whence);
365}
366
367/*
368 * This structure holds the nodes of the red-black tree used to store
369 * the directory entry in hash order.
370 */
371struct fname {
372 __u32 hash;
373 __u32 minor_hash;
374 struct rb_node rb_hash;
375 struct fname *next;
376 __u32 inode;
377 __u8 name_len;
378 __u8 file_type;
379 char name[0];
380};
381
382/*
383 * This functoin implements a non-recursive way of freeing all of the
384 * nodes in the red-black tree.
385 */
386static void free_rb_tree_fname(struct rb_root *root)
387{
388 struct fname *fname, *next;
389
390 rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
391 while (fname) {
392 struct fname *old = fname;
393 fname = fname->next;
394 kfree(old);
395 }
396
397 *root = RB_ROOT;
398}
399
400
401static struct dir_private_info *ext4_htree_create_dir_info(struct file *filp,
402 loff_t pos)
403{
404 struct dir_private_info *p;
405
406 p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
407 if (!p)
408 return NULL;
409 p->curr_hash = pos2maj_hash(filp, pos);
410 p->curr_minor_hash = pos2min_hash(filp, pos);
411 return p;
412}
413
414void ext4_htree_free_dir_info(struct dir_private_info *p)
415{
416 free_rb_tree_fname(&p->root);
417 kfree(p);
418}
419
420/*
421 * Given a directory entry, enter it into the fname rb tree.
422 *
423 * When filename encryption is enabled, the dirent will hold the
424 * encrypted filename, while the htree will hold decrypted filename.
425 * The decrypted filename is passed in via ent_name. parameter.
426 */
427int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
428 __u32 minor_hash,
429 struct ext4_dir_entry_2 *dirent,
430 struct ext4_str *ent_name)
431{
432 struct rb_node **p, *parent = NULL;
433 struct fname *fname, *new_fn;
434 struct dir_private_info *info;
435 int len;
436
437 info = dir_file->private_data;
438 p = &info->root.rb_node;
439
440 /* Create and allocate the fname structure */
441 len = sizeof(struct fname) + ent_name->len + 1;
442 new_fn = kzalloc(len, GFP_KERNEL);
443 if (!new_fn)
444 return -ENOMEM;
445 new_fn->hash = hash;
446 new_fn->minor_hash = minor_hash;
447 new_fn->inode = le32_to_cpu(dirent->inode);
448 new_fn->name_len = ent_name->len;
449 new_fn->file_type = dirent->file_type;
450 memcpy(new_fn->name, ent_name->name, ent_name->len);
451 new_fn->name[ent_name->len] = 0;
452
453 while (*p) {
454 parent = *p;
455 fname = rb_entry(parent, struct fname, rb_hash);
456
457 /*
458 * If the hash and minor hash match up, then we put
459 * them on a linked list. This rarely happens...
460 */
461 if ((new_fn->hash == fname->hash) &&
462 (new_fn->minor_hash == fname->minor_hash)) {
463 new_fn->next = fname->next;
464 fname->next = new_fn;
465 return 0;
466 }
467
468 if (new_fn->hash < fname->hash)
469 p = &(*p)->rb_left;
470 else if (new_fn->hash > fname->hash)
471 p = &(*p)->rb_right;
472 else if (new_fn->minor_hash < fname->minor_hash)
473 p = &(*p)->rb_left;
474 else /* if (new_fn->minor_hash > fname->minor_hash) */
475 p = &(*p)->rb_right;
476 }
477
478 rb_link_node(&new_fn->rb_hash, parent, p);
479 rb_insert_color(&new_fn->rb_hash, &info->root);
480 return 0;
481}
482
483
484
485/*
486 * This is a helper function for ext4_dx_readdir. It calls filldir
487 * for all entres on the fname linked list. (Normally there is only
488 * one entry on the linked list, unless there are 62 bit hash collisions.)
489 */
490static int call_filldir(struct file *file, struct dir_context *ctx,
491 struct fname *fname)
492{
493 struct dir_private_info *info = file->private_data;
494 struct inode *inode = file_inode(file);
495 struct super_block *sb = inode->i_sb;
496
497 if (!fname) {
498 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: comm %s: "
499 "called with null fname?!?", __func__, __LINE__,
500 inode->i_ino, current->comm);
501 return 0;
502 }
503 ctx->pos = hash2pos(file, fname->hash, fname->minor_hash);
504 while (fname) {
505 if (!dir_emit(ctx, fname->name,
506 fname->name_len,
507 fname->inode,
508 get_dtype(sb, fname->file_type))) {
509 info->extra_fname = fname;
510 return 1;
511 }
512 fname = fname->next;
513 }
514 return 0;
515}
516
517static int ext4_dx_readdir(struct file *file, struct dir_context *ctx)
518{
519 struct dir_private_info *info = file->private_data;
520 struct inode *inode = file_inode(file);
521 struct fname *fname;
522 int ret;
523
524 if (!info) {
525 info = ext4_htree_create_dir_info(file, ctx->pos);
526 if (!info)
527 return -ENOMEM;
528 file->private_data = info;
529 }
530
531 if (ctx->pos == ext4_get_htree_eof(file))
532 return 0; /* EOF */
533
534 /* Some one has messed with f_pos; reset the world */
535 if (info->last_pos != ctx->pos) {
536 free_rb_tree_fname(&info->root);
537 info->curr_node = NULL;
538 info->extra_fname = NULL;
539 info->curr_hash = pos2maj_hash(file, ctx->pos);
540 info->curr_minor_hash = pos2min_hash(file, ctx->pos);
541 }
542
543 /*
544 * If there are any leftover names on the hash collision
545 * chain, return them first.
546 */
547 if (info->extra_fname) {
548 if (call_filldir(file, ctx, info->extra_fname))
549 goto finished;
550 info->extra_fname = NULL;
551 goto next_node;
552 } else if (!info->curr_node)
553 info->curr_node = rb_first(&info->root);
554
555 while (1) {
556 /*
557 * Fill the rbtree if we have no more entries,
558 * or the inode has changed since we last read in the
559 * cached entries.
560 */
561 if ((!info->curr_node) ||
562 (file->f_version != inode->i_version)) {
563 info->curr_node = NULL;
564 free_rb_tree_fname(&info->root);
565 file->f_version = inode->i_version;
566 ret = ext4_htree_fill_tree(file, info->curr_hash,
567 info->curr_minor_hash,
568 &info->next_hash);
569 if (ret < 0)
570 return ret;
571 if (ret == 0) {
572 ctx->pos = ext4_get_htree_eof(file);
573 break;
574 }
575 info->curr_node = rb_first(&info->root);
576 }
577
578 fname = rb_entry(info->curr_node, struct fname, rb_hash);
579 info->curr_hash = fname->hash;
580 info->curr_minor_hash = fname->minor_hash;
581 if (call_filldir(file, ctx, fname))
582 break;
583 next_node:
584 info->curr_node = rb_next(info->curr_node);
585 if (info->curr_node) {
586 fname = rb_entry(info->curr_node, struct fname,
587 rb_hash);
588 info->curr_hash = fname->hash;
589 info->curr_minor_hash = fname->minor_hash;
590 } else {
591 if (info->next_hash == ~0) {
592 ctx->pos = ext4_get_htree_eof(file);
593 break;
594 }
595 info->curr_hash = info->next_hash;
596 info->curr_minor_hash = 0;
597 }
598 }
599finished:
600 info->last_pos = ctx->pos;
601 return 0;
602}
603
604static int ext4_dir_open(struct inode * inode, struct file * filp)
605{
606 if (ext4_encrypted_inode(inode))
607 return ext4_get_encryption_info(inode) ? -EACCES : 0;
608 return 0;
609}
610
611static int ext4_release_dir(struct inode *inode, struct file *filp)
612{
613 if (filp->private_data)
614 ext4_htree_free_dir_info(filp->private_data);
615
616 return 0;
617}
618
619int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf,
620 int buf_size)
621{
622 struct ext4_dir_entry_2 *de;
623 int nlen, rlen;
624 unsigned int offset = 0;
625 char *top;
626
627 de = (struct ext4_dir_entry_2 *)buf;
628 top = buf + buf_size;
629 while ((char *) de < top) {
630 if (ext4_check_dir_entry(dir, NULL, de, bh,
631 buf, buf_size, offset))
632 return -EFSCORRUPTED;
633 nlen = EXT4_DIR_REC_LEN(de->name_len);
634 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
635 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
636 offset += rlen;
637 }
638 if ((char *) de > top)
639 return -EFSCORRUPTED;
640
641 return 0;
642}
643
644const struct file_operations ext4_dir_operations = {
645 .llseek = ext4_dir_llseek,
646 .read = generic_read_dir,
647 .iterate = ext4_readdir,
648 .unlocked_ioctl = ext4_ioctl,
649#ifdef CONFIG_COMPAT
650 .compat_ioctl = ext4_compat_ioctl,
651#endif
652 .fsync = ext4_sync_file,
653 .open = ext4_dir_open,
654 .release = ext4_release_dir,
655};