fs/ext4/namei.c

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