blob: e8b365000d730d6a5f6f532bead918f535b83709 [file] [log] [blame]
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001/*
Mingming Cao617ba132006-10-11 01:20:53 -07002 * linux/fs/ext4/dir.c
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003 *
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 *
Mingming Cao617ba132006-10-11 01:20:53 -070015 * ext4 directory handling functions
Dave Kleikampac27a0e2006-10-11 01:20:50 -070016 *
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>
Dave Kleikampac27a0e2006-10-11 01:20:50 -070025#include <linux/buffer_head.h>
Dave Kleikampac27a0e2006-10-11 01:20:50 -070026#include <linux/slab.h>
Christoph Hellwig3dcf5452008-04-29 18:13:32 -040027#include "ext4.h"
Tao Ma65d165d2012-12-10 14:05:59 -050028#include "xattr.h"
Dave Kleikampac27a0e2006-10-11 01:20:50 -070029
Al Viro725bebb2013-05-17 16:08:53 -040030static int ext4_dx_readdir(struct file *, struct dir_context *);
Dave Kleikampac27a0e2006-10-11 01:20:50 -070031
Fan Yongd1f52732012-03-18 22:44:40 -040032/**
33 * Check if the given dir-inode refers to an htree-indexed directory
Anatol Pomozov70261f52013-08-28 14:40:12 -040034 * (or a directory which could potentially get converted to use htree
Fan Yongd1f52732012-03-18 22:44:40 -040035 * 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
Darrick J. Wonge2b911c2015-10-17 16:18:43 -040043 if (ext4_has_feature_dir_index(inode->i_sb) &&
Fan Yongd1f52732012-03-18 22:44:40 -040044 ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
Tao Ma8af0f082013-04-19 17:53:09 -040045 ((inode->i_size >> sb->s_blocksize_bits) == 1) ||
46 ext4_has_inline_data(inode)))
Fan Yongd1f52732012-03-18 22:44:40 -040047 return 1;
48
49 return 0;
50}
51
Theodore Ts'ocad3f002010-12-19 22:07:02 -050052/*
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...
Tao Ma65d165d2012-12-10 14:05:59 -050056 *
57 * bh passed here can be an inode block or a dir data block, depending
58 * on the inode inline data flag.
Theodore Ts'ocad3f002010-12-19 22:07:02 -050059 */
Theodore Ts'o60fd4da2010-07-27 11:54:40 -040060int __ext4_check_dir_entry(const char *function, unsigned int line,
Theodore Ts'of7c21172011-01-10 12:10:55 -050061 struct inode *dir, struct file *filp,
Theodore Ts'o60fd4da2010-07-27 11:54:40 -040062 struct ext4_dir_entry_2 *de,
Tao Ma226ba972012-12-10 14:05:58 -050063 struct buffer_head *bh, char *buf, int size,
Theodore Ts'o60fd4da2010-07-27 11:54:40 -040064 unsigned int offset)
Dave Kleikampac27a0e2006-10-11 01:20:50 -070065{
Theodore Ts'oaf5bc922008-09-08 22:25:24 -040066 const char *error_msg = NULL;
Wei Yongjun3d0518f2009-02-14 23:01:36 -050067 const int rlen = ext4_rec_len_from_disk(de->rec_len,
68 dir->i_sb->s_blocksize);
Dave Kleikampac27a0e2006-10-11 01:20:50 -070069
Theodore Ts'ocad3f002010-12-19 22:07:02 -050070 if (unlikely(rlen < EXT4_DIR_REC_LEN(1)))
Dave Kleikampac27a0e2006-10-11 01:20:50 -070071 error_msg = "rec_len is smaller than minimal";
Theodore Ts'ocad3f002010-12-19 22:07:02 -050072 else if (unlikely(rlen % 4 != 0))
Dave Kleikampac27a0e2006-10-11 01:20:50 -070073 error_msg = "rec_len % 4 != 0";
Theodore Ts'ocad3f002010-12-19 22:07:02 -050074 else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len)))
Dave Kleikampac27a0e2006-10-11 01:20:50 -070075 error_msg = "rec_len is too small for name_len";
Tao Ma226ba972012-12-10 14:05:58 -050076 else if (unlikely(((char *) de - buf) + rlen > size))
77 error_msg = "directory entry across range";
Theodore Ts'ocad3f002010-12-19 22:07:02 -050078 else if (unlikely(le32_to_cpu(de->inode) >
79 le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
Dave Kleikampac27a0e2006-10-11 01:20:50 -070080 error_msg = "inode out of bounds";
Theodore Ts'ocad3f002010-12-19 22:07:02 -050081 else
82 return 0;
Dave Kleikampac27a0e2006-10-11 01:20:50 -070083
Theodore Ts'of7c21172011-01-10 12:10:55 -050084 if (filp)
Dan Carpenter4fda4002012-02-20 17:53:05 -050085 ext4_error_file(filp, function, line, bh->b_blocknr,
Theodore Ts'of7c21172011-01-10 12:10:55 -050086 "bad entry in directory: %s - offset=%u(%u), "
87 "inode=%u, rec_len=%d, name_len=%d",
Tao Ma226ba972012-12-10 14:05:58 -050088 error_msg, (unsigned) (offset % size),
Theodore Ts'of7c21172011-01-10 12:10:55 -050089 offset, le32_to_cpu(de->inode),
90 rlen, de->name_len);
91 else
Dan Carpenter4fda4002012-02-20 17:53:05 -050092 ext4_error_inode(dir, function, line, bh->b_blocknr,
Theodore Ts'of7c21172011-01-10 12:10:55 -050093 "bad entry in directory: %s - offset=%u(%u), "
94 "inode=%u, rec_len=%d, name_len=%d",
Tao Ma226ba972012-12-10 14:05:58 -050095 error_msg, (unsigned) (offset % size),
Theodore Ts'of7c21172011-01-10 12:10:55 -050096 offset, le32_to_cpu(de->inode),
97 rlen, de->name_len);
98
Theodore Ts'ocad3f002010-12-19 22:07:02 -050099 return 1;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700100}
101
Al Viro725bebb2013-05-17 16:08:53 -0400102static int ext4_readdir(struct file *file, struct dir_context *ctx)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700103{
Theodore Ts'o498e5f22008-11-05 00:14:04 -0500104 unsigned int offset;
Giedrius Rekasiusaa13d5f2014-05-27 12:48:55 -0400105 int i;
Mingming Cao617ba132006-10-11 01:20:53 -0700106 struct ext4_dir_entry_2 *de;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700107 int err;
Al Viro725bebb2013-05-17 16:08:53 -0400108 struct inode *inode = file_inode(file);
Fan Yongd1f52732012-03-18 22:44:40 -0400109 struct super_block *sb = inode->i_sb;
Michael Halcrow44614712015-04-12 01:09:05 -0400110 struct buffer_head *bh = NULL;
Eric Sandeen9d9f1772008-10-09 11:15:52 -0400111 int dir_has_error = 0;
Jaegeuk Kima7550b32016-07-10 14:01:03 -0400112 struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700113
Theodore Ts'o28b4c262016-02-07 19:35:05 -0500114 if (ext4_encrypted_inode(inode)) {
Jaegeuk Kima7550b32016-07-10 14:01:03 -0400115 err = fscrypt_get_encryption_info(inode);
Theodore Ts'o28b4c262016-02-07 19:35:05 -0500116 if (err && err != -ENOKEY)
117 return err;
118 }
119
Fan Yongd1f52732012-03-18 22:44:40 -0400120 if (is_dx_dir(inode)) {
Al Viro725bebb2013-05-17 16:08:53 -0400121 err = ext4_dx_readdir(file, ctx);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700122 if (err != ERR_BAD_DX_DIR) {
Al Viro725bebb2013-05-17 16:08:53 -0400123 return err;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700124 }
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 */
Al Viro725bebb2013-05-17 16:08:53 -0400129 ext4_clear_inode_flag(file_inode(file),
Theodore Ts'o07a03822010-06-14 09:54:48 -0400130 EXT4_INODE_INDEX);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700131 }
Tao Ma8af0f082013-04-19 17:53:09 -0400132
133 if (ext4_has_inline_data(inode)) {
134 int has_inline_data = 1;
Michael Halcrow44614712015-04-12 01:09:05 -0400135 err = ext4_read_inline_dir(file, ctx,
Tao Ma8af0f082013-04-19 17:53:09 -0400136 &has_inline_data);
137 if (has_inline_data)
Michael Halcrow44614712015-04-12 01:09:05 -0400138 return err;
139 }
140
Theodore Ts'ob7236e22015-05-18 13:17:47 -0400141 if (ext4_encrypted_inode(inode)) {
Jaegeuk Kima7550b32016-07-10 14:01:03 -0400142 err = fscrypt_fname_alloc_buffer(inode, EXT4_NAME_LEN, &fstr);
Theodore Ts'ob7236e22015-05-18 13:17:47 -0400143 if (err < 0)
Michael Halcrow44614712015-04-12 01:09:05 -0400144 return err;
Tao Ma8af0f082013-04-19 17:53:09 -0400145 }
146
Al Viro725bebb2013-05-17 16:08:53 -0400147 offset = ctx->pos & (sb->s_blocksize - 1);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700148
Al Viro725bebb2013-05-17 16:08:53 -0400149 while (ctx->pos < inode->i_size) {
Theodore Ts'o2ed88682010-05-16 20:00:00 -0400150 struct ext4_map_blocks map;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700151
Theodore Ts'o1f60fbe2016-04-23 22:50:07 -0400152 if (fatal_signal_pending(current)) {
153 err = -ERESTARTSYS;
154 goto errout;
155 }
156 cond_resched();
Al Viro725bebb2013-05-17 16:08:53 -0400157 map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb);
Theodore Ts'o2ed88682010-05-16 20:00:00 -0400158 map.m_len = 1;
159 err = ext4_map_blocks(NULL, inode, &map, 0);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700160 if (err > 0) {
Theodore Ts'o2ed88682010-05-16 20:00:00 -0400161 pgoff_t index = map.m_pblk >>
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300162 (PAGE_SHIFT - inode->i_blkbits);
Al Viro725bebb2013-05-17 16:08:53 -0400163 if (!ra_has_index(&file->f_ra, index))
Rusty Russellcf914a72007-07-19 01:48:08 -0700164 page_cache_sync_readahead(
Fengguang Wudc7868f2007-07-19 01:48:04 -0700165 sb->s_bdev->bd_inode->i_mapping,
Al Viro725bebb2013-05-17 16:08:53 -0400166 &file->f_ra, file,
Rusty Russellcf914a72007-07-19 01:48:08 -0700167 index, 1);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300168 file->f_ra.prev_pos = (loff_t)index << PAGE_SHIFT;
Theodore Ts'o1c215022014-08-29 20:52:15 -0400169 bh = ext4_bread(NULL, inode, map.m_lblk, 0);
Kirill Tkhaic906f382016-02-16 00:20:19 -0500170 if (IS_ERR(bh)) {
171 err = PTR_ERR(bh);
172 bh = NULL;
173 goto errout;
174 }
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700175 }
176
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700177 if (!bh) {
Eric Sandeen9d9f1772008-10-09 11:15:52 -0400178 if (!dir_has_error) {
Al Viro725bebb2013-05-17 16:08:53 -0400179 EXT4_ERROR_FILE(file, 0,
Theodore Ts'of7c21172011-01-10 12:10:55 -0500180 "directory contains a "
181 "hole at offset %llu",
Al Viro725bebb2013-05-17 16:08:53 -0400182 (unsigned long long) ctx->pos);
Eric Sandeen9d9f1772008-10-09 11:15:52 -0400183 dir_has_error = 1;
184 }
Eric Sandeene6c40212006-12-06 20:36:28 -0800185 /* corrupt size? Maybe no more blocks to read */
Al Viro725bebb2013-05-17 16:08:53 -0400186 if (ctx->pos > inode->i_blocks << 9)
Eric Sandeene6c40212006-12-06 20:36:28 -0800187 break;
Al Viro725bebb2013-05-17 16:08:53 -0400188 ctx->pos += sb->s_blocksize - offset;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700189 continue;
190 }
191
Darrick J. Wongb0336e82012-04-29 18:41:10 -0400192 /* Check the checksum */
193 if (!buffer_verified(bh) &&
194 !ext4_dirent_csum_verify(inode,
195 (struct ext4_dir_entry *)bh->b_data)) {
Al Viro725bebb2013-05-17 16:08:53 -0400196 EXT4_ERROR_FILE(file, 0, "directory fails checksum "
Darrick J. Wongb0336e82012-04-29 18:41:10 -0400197 "at offset %llu",
Al Viro725bebb2013-05-17 16:08:53 -0400198 (unsigned long long)ctx->pos);
199 ctx->pos += sb->s_blocksize - offset;
Guo Chaod5ac7772013-01-28 21:23:24 -0500200 brelse(bh);
Michael Halcrow44614712015-04-12 01:09:05 -0400201 bh = NULL;
Darrick J. Wongb0336e82012-04-29 18:41:10 -0400202 continue;
203 }
204 set_buffer_verified(bh);
205
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700206 /* If the dir block has changed since the last call to
207 * readdir(2), then we might be pointing to an invalid
208 * dirent right now. Scan from the start of the block
209 * to make sure. */
Al Viro725bebb2013-05-17 16:08:53 -0400210 if (file->f_version != inode->i_version) {
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700211 for (i = 0; i < sb->s_blocksize && i < offset; ) {
Mingming Cao617ba132006-10-11 01:20:53 -0700212 de = (struct ext4_dir_entry_2 *)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700213 (bh->b_data + i);
214 /* It's too expensive to do a full
215 * dirent test each time round this
216 * loop, but we do have to test at
217 * least that it is non-zero. A
218 * failure will be detected in the
219 * dirent test below. */
Wei Yongjun3d0518f2009-02-14 23:01:36 -0500220 if (ext4_rec_len_from_disk(de->rec_len,
221 sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700222 break;
Wei Yongjun3d0518f2009-02-14 23:01:36 -0500223 i += ext4_rec_len_from_disk(de->rec_len,
224 sb->s_blocksize);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700225 }
226 offset = i;
Al Viro725bebb2013-05-17 16:08:53 -0400227 ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700228 | offset;
Al Viro725bebb2013-05-17 16:08:53 -0400229 file->f_version = inode->i_version;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700230 }
231
Al Viro725bebb2013-05-17 16:08:53 -0400232 while (ctx->pos < inode->i_size
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700233 && offset < sb->s_blocksize) {
Mingming Cao617ba132006-10-11 01:20:53 -0700234 de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
Al Viro725bebb2013-05-17 16:08:53 -0400235 if (ext4_check_dir_entry(inode, file, de, bh,
Tao Ma226ba972012-12-10 14:05:58 -0500236 bh->b_data, bh->b_size,
237 offset)) {
Andrew Morton63f57932006-10-11 01:21:24 -0700238 /*
Al Viro725bebb2013-05-17 16:08:53 -0400239 * On error, skip to the next block
Andrew Morton63f57932006-10-11 01:21:24 -0700240 */
Al Viro725bebb2013-05-17 16:08:53 -0400241 ctx->pos = (ctx->pos |
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700242 (sb->s_blocksize - 1)) + 1;
Al Viro725bebb2013-05-17 16:08:53 -0400243 break;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700244 }
Wei Yongjun3d0518f2009-02-14 23:01:36 -0500245 offset += ext4_rec_len_from_disk(de->rec_len,
246 sb->s_blocksize);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700247 if (le32_to_cpu(de->inode)) {
Theodore Ts'ob7236e22015-05-18 13:17:47 -0400248 if (!ext4_encrypted_inode(inode)) {
Michael Halcrow44614712015-04-12 01:09:05 -0400249 if (!dir_emit(ctx, de->name,
250 de->name_len,
251 le32_to_cpu(de->inode),
252 get_dtype(sb, de->file_type)))
253 goto done;
254 } else {
Jaegeuk Kima7550b32016-07-10 14:01:03 -0400255 int save_len = fstr.len;
256 struct fscrypt_str de_name =
257 FSTR_INIT(de->name,
258 de->name_len);
Theodore Ts'od2299592015-05-18 13:15:47 -0400259
Michael Halcrow44614712015-04-12 01:09:05 -0400260 /* Directory is encrypted */
Jaegeuk Kima7550b32016-07-10 14:01:03 -0400261 err = fscrypt_fname_disk_to_usr(inode,
262 0, 0, &de_name, &fstr);
Eric Biggersef1eb3a2016-09-15 17:25:55 -0400263 de_name = fstr;
Jaegeuk Kima7550b32016-07-10 14:01:03 -0400264 fstr.len = save_len;
Eric Biggersef1eb3a2016-09-15 17:25:55 -0400265 if (err)
Michael Halcrow44614712015-04-12 01:09:05 -0400266 goto errout;
267 if (!dir_emit(ctx,
Eric Biggersef1eb3a2016-09-15 17:25:55 -0400268 de_name.name, de_name.len,
Michael Halcrow44614712015-04-12 01:09:05 -0400269 le32_to_cpu(de->inode),
270 get_dtype(sb, de->file_type)))
271 goto done;
Al Viro725bebb2013-05-17 16:08:53 -0400272 }
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700273 }
Al Viro725bebb2013-05-17 16:08:53 -0400274 ctx->pos += ext4_rec_len_from_disk(de->rec_len,
Wei Yongjun3d0518f2009-02-14 23:01:36 -0500275 sb->s_blocksize);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700276 }
Al Viroae053272016-05-12 20:36:01 -0400277 if ((ctx->pos < inode->i_size) && !dir_relax_shared(inode))
Michael Halcrow44614712015-04-12 01:09:05 -0400278 goto done;
Theodore Ts'oaf5bc922008-09-08 22:25:24 -0400279 brelse(bh);
Michael Halcrow44614712015-04-12 01:09:05 -0400280 bh = NULL;
281 offset = 0;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700282 }
Michael Halcrow44614712015-04-12 01:09:05 -0400283done:
284 err = 0;
285errout:
286#ifdef CONFIG_EXT4_FS_ENCRYPTION
Jaegeuk Kima7550b32016-07-10 14:01:03 -0400287 fscrypt_fname_free_buffer(&fstr);
Michael Halcrow44614712015-04-12 01:09:05 -0400288#endif
289 brelse(bh);
290 return err;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700291}
292
Fan Yongd1f52732012-03-18 22:44:40 -0400293static inline int is_32bit_api(void)
294{
295#ifdef CONFIG_COMPAT
Andy Lutomirski121cef82016-03-22 14:25:04 -0700296 return in_compat_syscall();
Fan Yongd1f52732012-03-18 22:44:40 -0400297#else
298 return (BITS_PER_LONG == 32);
299#endif
300}
301
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700302/*
303 * These functions convert from the major/minor hash to an f_pos
Fan Yongd1f52732012-03-18 22:44:40 -0400304 * value for dx directories
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700305 *
Fan Yongd1f52732012-03-18 22:44:40 -0400306 * Upper layer (for example NFS) should specify FMODE_32BITHASH or
307 * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
308 * directly on both 32-bit and 64-bit nodes, under such case, neither
309 * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700310 */
Fan Yongd1f52732012-03-18 22:44:40 -0400311static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
312{
313 if ((filp->f_mode & FMODE_32BITHASH) ||
314 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
315 return major >> 1;
316 else
317 return ((__u64)(major >> 1) << 32) | (__u64)minor;
318}
319
320static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
321{
322 if ((filp->f_mode & FMODE_32BITHASH) ||
323 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
324 return (pos << 1) & 0xffffffff;
325 else
326 return ((pos >> 32) << 1) & 0xffffffff;
327}
328
329static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
330{
331 if ((filp->f_mode & FMODE_32BITHASH) ||
332 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
333 return 0;
334 else
335 return pos & 0xffffffff;
336}
337
338/*
339 * Return 32- or 64-bit end-of-file for dx directories
340 */
341static inline loff_t ext4_get_htree_eof(struct file *filp)
342{
343 if ((filp->f_mode & FMODE_32BITHASH) ||
344 (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
345 return EXT4_HTREE_EOF_32BIT;
346 else
347 return EXT4_HTREE_EOF_64BIT;
348}
349
350
351/*
Eric Sandeenec7268c2012-04-30 13:14:03 -0500352 * ext4_dir_llseek() calls generic_file_llseek_size to handle htree
353 * directories, where the "offset" is in terms of the filename hash
354 * value instead of the byte offset.
Fan Yongd1f52732012-03-18 22:44:40 -0400355 *
Eric Sandeenec7268c2012-04-30 13:14:03 -0500356 * Because we may return a 64-bit hash that is well beyond offset limits,
357 * we need to pass the max hash as the maximum allowable offset in
358 * the htree directory case.
359 *
360 * For non-htree, ext4_llseek already chooses the proper max offset.
Fan Yongd1f52732012-03-18 22:44:40 -0400361 */
Zheng Liud4e43952013-03-02 17:24:05 -0500362static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence)
Fan Yongd1f52732012-03-18 22:44:40 -0400363{
364 struct inode *inode = file->f_mapping->host;
Fan Yongd1f52732012-03-18 22:44:40 -0400365 int dx_dir = is_dx_dir(inode);
Eric Sandeenec7268c2012-04-30 13:14:03 -0500366 loff_t htree_max = ext4_get_htree_eof(file);
Fan Yongd1f52732012-03-18 22:44:40 -0400367
Eric Sandeenec7268c2012-04-30 13:14:03 -0500368 if (likely(dx_dir))
Andrew Morton965c8e52012-12-17 15:59:39 -0800369 return generic_file_llseek_size(file, offset, whence,
Eric Sandeenec7268c2012-04-30 13:14:03 -0500370 htree_max, htree_max);
371 else
Andrew Morton965c8e52012-12-17 15:59:39 -0800372 return ext4_llseek(file, offset, whence);
Fan Yongd1f52732012-03-18 22:44:40 -0400373}
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700374
375/*
376 * This structure holds the nodes of the red-black tree used to store
377 * the directory entry in hash order.
378 */
379struct fname {
380 __u32 hash;
381 __u32 minor_hash;
382 struct rb_node rb_hash;
383 struct fname *next;
384 __u32 inode;
385 __u8 name_len;
386 __u8 file_type;
387 char name[0];
388};
389
390/*
391 * This functoin implements a non-recursive way of freeing all of the
392 * nodes in the red-black tree.
393 */
394static void free_rb_tree_fname(struct rb_root *root)
395{
Cody P Schaferd1866bd2014-01-23 15:56:10 -0800396 struct fname *fname, *next;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700397
Cody P Schaferd1866bd2014-01-23 15:56:10 -0800398 rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700399 while (fname) {
Theodore Ts'oaf5bc922008-09-08 22:25:24 -0400400 struct fname *old = fname;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700401 fname = fname->next;
Theodore Ts'oaf5bc922008-09-08 22:25:24 -0400402 kfree(old);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700403 }
Cody P Schaferd1866bd2014-01-23 15:56:10 -0800404
405 *root = RB_ROOT;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700406}
407
408
Fan Yongd1f52732012-03-18 22:44:40 -0400409static struct dir_private_info *ext4_htree_create_dir_info(struct file *filp,
410 loff_t pos)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700411{
412 struct dir_private_info *p;
413
Shen Feng69baee02008-07-11 19:27:31 -0400414 p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700415 if (!p)
416 return NULL;
Fan Yongd1f52732012-03-18 22:44:40 -0400417 p->curr_hash = pos2maj_hash(filp, pos);
418 p->curr_minor_hash = pos2min_hash(filp, pos);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700419 return p;
420}
421
Mingming Cao617ba132006-10-11 01:20:53 -0700422void ext4_htree_free_dir_info(struct dir_private_info *p)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700423{
424 free_rb_tree_fname(&p->root);
425 kfree(p);
426}
427
428/*
429 * Given a directory entry, enter it into the fname rb tree.
Theodore Ts'o2f618302015-04-12 00:56:26 -0400430 *
431 * When filename encryption is enabled, the dirent will hold the
432 * encrypted filename, while the htree will hold decrypted filename.
433 * The decrypted filename is passed in via ent_name. parameter.
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700434 */
Mingming Cao617ba132006-10-11 01:20:53 -0700435int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700436 __u32 minor_hash,
Theodore Ts'o2f618302015-04-12 00:56:26 -0400437 struct ext4_dir_entry_2 *dirent,
Jaegeuk Kima7550b32016-07-10 14:01:03 -0400438 struct fscrypt_str *ent_name)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700439{
440 struct rb_node **p, *parent = NULL;
Theodore Ts'oaf5bc922008-09-08 22:25:24 -0400441 struct fname *fname, *new_fn;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700442 struct dir_private_info *info;
443 int len;
444
Joe Perchesa271fe82010-07-27 11:56:04 -0400445 info = dir_file->private_data;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700446 p = &info->root.rb_node;
447
448 /* Create and allocate the fname structure */
Theodore Ts'o2f618302015-04-12 00:56:26 -0400449 len = sizeof(struct fname) + ent_name->len + 1;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700450 new_fn = kzalloc(len, GFP_KERNEL);
451 if (!new_fn)
452 return -ENOMEM;
453 new_fn->hash = hash;
454 new_fn->minor_hash = minor_hash;
455 new_fn->inode = le32_to_cpu(dirent->inode);
Theodore Ts'o2f618302015-04-12 00:56:26 -0400456 new_fn->name_len = ent_name->len;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700457 new_fn->file_type = dirent->file_type;
Theodore Ts'o2f618302015-04-12 00:56:26 -0400458 memcpy(new_fn->name, ent_name->name, ent_name->len);
459 new_fn->name[ent_name->len] = 0;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700460
461 while (*p) {
462 parent = *p;
463 fname = rb_entry(parent, struct fname, rb_hash);
464
465 /*
466 * If the hash and minor hash match up, then we put
467 * them on a linked list. This rarely happens...
468 */
469 if ((new_fn->hash == fname->hash) &&
470 (new_fn->minor_hash == fname->minor_hash)) {
471 new_fn->next = fname->next;
472 fname->next = new_fn;
473 return 0;
474 }
475
476 if (new_fn->hash < fname->hash)
477 p = &(*p)->rb_left;
478 else if (new_fn->hash > fname->hash)
479 p = &(*p)->rb_right;
480 else if (new_fn->minor_hash < fname->minor_hash)
481 p = &(*p)->rb_left;
482 else /* if (new_fn->minor_hash > fname->minor_hash) */
483 p = &(*p)->rb_right;
484 }
485
486 rb_link_node(&new_fn->rb_hash, parent, p);
487 rb_insert_color(&new_fn->rb_hash, &info->root);
488 return 0;
489}
490
491
492
493/*
Mingming Cao617ba132006-10-11 01:20:53 -0700494 * This is a helper function for ext4_dx_readdir. It calls filldir
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700495 * for all entres on the fname linked list. (Normally there is only
496 * one entry on the linked list, unless there are 62 bit hash collisions.)
497 */
Al Viro725bebb2013-05-17 16:08:53 -0400498static int call_filldir(struct file *file, struct dir_context *ctx,
499 struct fname *fname)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700500{
Al Viro725bebb2013-05-17 16:08:53 -0400501 struct dir_private_info *info = file->private_data;
502 struct inode *inode = file_inode(file);
503 struct super_block *sb = inode->i_sb;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700504
505 if (!fname) {
Theodore Ts'o92b97812012-03-19 23:41:49 -0400506 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: comm %s: "
507 "called with null fname?!?", __func__, __LINE__,
508 inode->i_ino, current->comm);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700509 return 0;
510 }
Al Viro725bebb2013-05-17 16:08:53 -0400511 ctx->pos = hash2pos(file, fname->hash, fname->minor_hash);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700512 while (fname) {
Al Viro725bebb2013-05-17 16:08:53 -0400513 if (!dir_emit(ctx, fname->name,
514 fname->name_len,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700515 fname->inode,
Al Viro725bebb2013-05-17 16:08:53 -0400516 get_dtype(sb, fname->file_type))) {
Theodore Ts'od0156412008-08-19 21:57:43 -0400517 info->extra_fname = fname;
Al Viro725bebb2013-05-17 16:08:53 -0400518 return 1;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700519 }
520 fname = fname->next;
521 }
522 return 0;
523}
524
Al Viro725bebb2013-05-17 16:08:53 -0400525static int ext4_dx_readdir(struct file *file, struct dir_context *ctx)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700526{
Al Viro725bebb2013-05-17 16:08:53 -0400527 struct dir_private_info *info = file->private_data;
528 struct inode *inode = file_inode(file);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700529 struct fname *fname;
530 int ret;
531
532 if (!info) {
Al Viro725bebb2013-05-17 16:08:53 -0400533 info = ext4_htree_create_dir_info(file, ctx->pos);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700534 if (!info)
535 return -ENOMEM;
Al Viro725bebb2013-05-17 16:08:53 -0400536 file->private_data = info;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700537 }
538
Al Viro725bebb2013-05-17 16:08:53 -0400539 if (ctx->pos == ext4_get_htree_eof(file))
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700540 return 0; /* EOF */
541
542 /* Some one has messed with f_pos; reset the world */
Al Viro725bebb2013-05-17 16:08:53 -0400543 if (info->last_pos != ctx->pos) {
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700544 free_rb_tree_fname(&info->root);
545 info->curr_node = NULL;
546 info->extra_fname = NULL;
Al Viro725bebb2013-05-17 16:08:53 -0400547 info->curr_hash = pos2maj_hash(file, ctx->pos);
548 info->curr_minor_hash = pos2min_hash(file, ctx->pos);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700549 }
550
551 /*
552 * If there are any leftover names on the hash collision
553 * chain, return them first.
554 */
Theodore Ts'od0156412008-08-19 21:57:43 -0400555 if (info->extra_fname) {
Al Viro725bebb2013-05-17 16:08:53 -0400556 if (call_filldir(file, ctx, info->extra_fname))
Theodore Ts'od0156412008-08-19 21:57:43 -0400557 goto finished;
Theodore Ts'od0156412008-08-19 21:57:43 -0400558 info->extra_fname = NULL;
Theodore Ts'o3c37fc82008-10-25 11:39:08 -0400559 goto next_node;
Theodore Ts'od0156412008-08-19 21:57:43 -0400560 } else if (!info->curr_node)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700561 info->curr_node = rb_first(&info->root);
562
563 while (1) {
564 /*
565 * Fill the rbtree if we have no more entries,
566 * or the inode has changed since we last read in the
567 * cached entries.
568 */
569 if ((!info->curr_node) ||
Al Viro725bebb2013-05-17 16:08:53 -0400570 (file->f_version != inode->i_version)) {
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700571 info->curr_node = NULL;
572 free_rb_tree_fname(&info->root);
Al Viro725bebb2013-05-17 16:08:53 -0400573 file->f_version = inode->i_version;
574 ret = ext4_htree_fill_tree(file, info->curr_hash,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700575 info->curr_minor_hash,
576 &info->next_hash);
577 if (ret < 0)
578 return ret;
579 if (ret == 0) {
Al Viro725bebb2013-05-17 16:08:53 -0400580 ctx->pos = ext4_get_htree_eof(file);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700581 break;
582 }
583 info->curr_node = rb_first(&info->root);
584 }
585
586 fname = rb_entry(info->curr_node, struct fname, rb_hash);
587 info->curr_hash = fname->hash;
588 info->curr_minor_hash = fname->minor_hash;
Al Viro725bebb2013-05-17 16:08:53 -0400589 if (call_filldir(file, ctx, fname))
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700590 break;
Theodore Ts'o3c37fc82008-10-25 11:39:08 -0400591 next_node:
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700592 info->curr_node = rb_next(info->curr_node);
Theodore Ts'o3c37fc82008-10-25 11:39:08 -0400593 if (info->curr_node) {
594 fname = rb_entry(info->curr_node, struct fname,
595 rb_hash);
596 info->curr_hash = fname->hash;
597 info->curr_minor_hash = fname->minor_hash;
598 } else {
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700599 if (info->next_hash == ~0) {
Al Viro725bebb2013-05-17 16:08:53 -0400600 ctx->pos = ext4_get_htree_eof(file);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700601 break;
602 }
603 info->curr_hash = info->next_hash;
604 info->curr_minor_hash = 0;
605 }
606 }
607finished:
Al Viro725bebb2013-05-17 16:08:53 -0400608 info->last_pos = ctx->pos;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700609 return 0;
610}
611
Theodore Ts'o6bc445e2015-05-31 13:34:57 -0400612static int ext4_dir_open(struct inode * inode, struct file * filp)
613{
614 if (ext4_encrypted_inode(inode))
Jaegeuk Kima7550b32016-07-10 14:01:03 -0400615 return fscrypt_get_encryption_info(inode) ? -EACCES : 0;
Theodore Ts'o6bc445e2015-05-31 13:34:57 -0400616 return 0;
617}
618
Theodore Ts'oaf5bc922008-09-08 22:25:24 -0400619static int ext4_release_dir(struct inode *inode, struct file *filp)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700620{
Andrew Morton63f57932006-10-11 01:21:24 -0700621 if (filp->private_data)
Mingming Cao617ba132006-10-11 01:20:53 -0700622 ext4_htree_free_dir_info(filp->private_data);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700623
624 return 0;
625}
Fan Yongd1f52732012-03-18 22:44:40 -0400626
Darrick J. Wong40b163f2014-07-28 13:06:26 -0400627int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf,
628 int buf_size)
629{
630 struct ext4_dir_entry_2 *de;
Eric Engestrom18017472016-09-30 02:14:56 -0400631 int rlen;
Darrick J. Wong40b163f2014-07-28 13:06:26 -0400632 unsigned int offset = 0;
633 char *top;
634
635 de = (struct ext4_dir_entry_2 *)buf;
636 top = buf + buf_size;
637 while ((char *) de < top) {
638 if (ext4_check_dir_entry(dir, NULL, de, bh,
639 buf, buf_size, offset))
Darrick J. Wong6a797d22015-10-17 16:16:04 -0400640 return -EFSCORRUPTED;
Darrick J. Wong40b163f2014-07-28 13:06:26 -0400641 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
642 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
643 offset += rlen;
644 }
645 if ((char *) de > top)
Darrick J. Wong6a797d22015-10-17 16:16:04 -0400646 return -EFSCORRUPTED;
Darrick J. Wong40b163f2014-07-28 13:06:26 -0400647
648 return 0;
649}
650
Fan Yongd1f52732012-03-18 22:44:40 -0400651const struct file_operations ext4_dir_operations = {
652 .llseek = ext4_dir_llseek,
653 .read = generic_read_dir,
Al Viroae053272016-05-12 20:36:01 -0400654 .iterate_shared = ext4_readdir,
Fan Yongd1f52732012-03-18 22:44:40 -0400655 .unlocked_ioctl = ext4_ioctl,
656#ifdef CONFIG_COMPAT
657 .compat_ioctl = ext4_compat_ioctl,
658#endif
659 .fsync = ext4_sync_file,
Theodore Ts'o6bc445e2015-05-31 13:34:57 -0400660 .open = ext4_dir_open,
Fan Yongd1f52732012-03-18 22:44:40 -0400661 .release = ext4_release_dir,
662};