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 (card@masi.ibp.fr)
   7  * Laboratoire MASI - Institut Blaise Pascal
   8  * Universite Pierre et Marie Curie (Paris VI)
   9  *
  10  *  from
  11  *
  12  *  linux/fs/minix/namei.c
  13  *
  14  *  Copyright (C) 1991, 1992  Linus Torvalds
  15  *
  16  *  Big-endian to little-endian byte-swapping/bitmaps by
  17  *        David S. Miller (davem@caip.rutgers.edu), 1995
  18  *  Directory entry file type support and forward compatibility hooks
  19  *      for B-tree directories by Theodore Ts'o (tytso@mit.edu), 1998
  20  *  Hash Tree Directory indexing (c)
  21  *      Daniel Phillips, 2001
  22  *  Hash Tree Directory indexing porting
  23  *      Christopher Li, 2002
  24  *  Hash Tree Directory indexing cleanup
  25  *      Theodore Ts'o, 2002
  26  */
  27
  28 #include <linux/fs.h>
  29 #include <linux/pagemap.h>
  30 #include <linux/time.h>
  31 #include <linux/fcntl.h>
  32 #include <linux/stat.h>
  33 #include <linux/string.h>
  34 #include <linux/quotaops.h>
  35 #include <linux/buffer_head.h>
  36 #include <linux/bio.h>
  37 #include <linux/iversion.h>
  38 #include <linux/unicode.h>
  39 #include "ext4.h"
  40 #include "ext4_jbd2.h"
  41
  42 #include "xattr.h"
  43 #include "acl.h"
  44
  45 #include <trace/events/ext4.h>
  46 /*
  47  * define how far ahead to read directories while searching them.
  48  */
  49 #define NAMEI_RA_CHUNKS  2
  50 #define NAMEI_RA_BLOCKS  4
  51 #define NAMEI_RA_SIZE        (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS)
  52
  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
 347 #ifdef PARANOID
 348         struct ext4_dir_entry *d, *top;
 349
 350         d = (struct ext4_dir_entry *)bh->b_data;
 351         top = (struct ext4_dir_entry *)(bh->b_data +
 352                 (EXT4_BLOCK_SIZE(inode->i_sb) -
 353                  sizeof(struct ext4_dir_entry_tail)));
 354         while (d < top && d->rec_len)
 355                 d = (struct ext4_dir_entry *)(((void *)d) +
 356                     le16_to_cpu(d->rec_len));
 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             le16_to_cpu(t->det_rec_len) != sizeof(struct ext4_dir_entry_tail) ||
 368             t->det_reserved_zero2 ||
 369             t->det_reserved_ft != EXT4_FT_DIR_CSUM)
 370                 return NULL;
 371
 372         return t;
 373 }
 374
 375 static __le32 ext4_dirblock_csum(struct inode *inode, void *dirent, int size)
 376 {
 377         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 378         struct ext4_inode_info *ei = EXT4_I(inode);
 379         __u32 csum;
 380
 381         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
 382         return cpu_to_le32(csum);
 383 }
 384
 385 #define warn_no_space_for_csum(inode)                                   \
 386         __warn_no_space_for_csum((inode), __func__, __LINE__)
 387
 388 static void __warn_no_space_for_csum(struct inode *inode, const char *func,
 389                                      unsigned int line)
 390 {
 391         __ext4_warning_inode(inode, func, line,
 392                 "No space for directory leaf checksum. Please run e2fsck -D.");
 393 }
 394
 395 int ext4_dirblock_csum_verify(struct inode *inode, struct buffer_head *bh)
 396 {
 397         struct ext4_dir_entry_tail *t;
 398
 399         if (!ext4_has_metadata_csum(inode->i_sb))
 400                 return 1;
 401
 402         t = get_dirent_tail(inode, bh);
 403         if (!t) {
 404                 warn_no_space_for_csum(inode);
 405                 return 0;
 406         }
 407
 408         if (t->det_checksum != ext4_dirblock_csum(inode, bh->b_data,
 409                                                   (char *)t - bh->b_data))
 410                 return 0;
 411
 412         return 1;
 413 }
 414
 415 static void ext4_dirblock_csum_set(struct inode *inode,
 416                                  struct buffer_head *bh)
 417 {
 418         struct ext4_dir_entry_tail *t;
 419
 420         if (!ext4_has_metadata_csum(inode->i_sb))
 421                 return;
 422
 423         t = get_dirent_tail(inode, bh);
 424         if (!t) {
 425                 warn_no_space_for_csum(inode);
 426                 return;
 427         }
 428
 429         t->det_checksum = ext4_dirblock_csum(inode, bh->b_data,
 430                                              (char *)t - bh->b_data);
 431 }
 432
 433 int ext4_handle_dirty_dirblock(handle_t *handle,
 434                                struct inode *inode,
 435                                struct buffer_head *bh)
 436 {
 437         ext4_dirblock_csum_set(inode, bh);
 438         return ext4_handle_dirty_metadata(handle, inode, bh);
 439 }
 440
 441 static struct dx_countlimit *get_dx_countlimit(struct inode *inode,
 442                                                struct ext4_dir_entry *dirent,
 443                                                int *offset)
 444 {
 445         struct ext4_dir_entry *dp;
 446         struct dx_root_info *root;
 447         int count_offset;
 448
 449         if (le16_to_cpu(dirent->rec_len) == EXT4_BLOCK_SIZE(inode->i_sb))
 450                 count_offset = 8;
 451         else if (le16_to_cpu(dirent->rec_len) == 12) {
 452                 dp = (struct ext4_dir_entry *)(((void *)dirent) + 12);
 453                 if (le16_to_cpu(dp->rec_len) !=
 454                     EXT4_BLOCK_SIZE(inode->i_sb) - 12)
 455                         return NULL;
 456                 root = (struct dx_root_info *)(((void *)dp + 12));
 457                 if (root->reserved_zero ||
 458                     root->info_length != sizeof(struct dx_root_info))
 459                         return NULL;
 460                 count_offset = 32;
 461         } else
 462                 return NULL;
 463
 464         if (offset)
 465                 *offset = count_offset;
 466         return (struct dx_countlimit *)(((void *)dirent) + count_offset);
 467 }
 468
 469 static __le32 ext4_dx_csum(struct inode *inode, struct ext4_dir_entry *dirent,
 470                            int count_offset, int count, struct dx_tail *t)
 471 {
 472         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 473         struct ext4_inode_info *ei = EXT4_I(inode);
 474         __u32 csum;
 475         int size;
 476         __u32 dummy_csum = 0;
 477         int offset = offsetof(struct dx_tail, dt_checksum);
 478
 479         size = count_offset + (count * sizeof(struct dx_entry));
 480         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
 481         csum = ext4_chksum(sbi, csum, (__u8 *)t, offset);
 482         csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
 483
 484         return cpu_to_le32(csum);
 485 }
 486
 487 static int ext4_dx_csum_verify(struct inode *inode,
 488                                struct ext4_dir_entry *dirent)
 489 {
 490         struct dx_countlimit *c;
 491         struct dx_tail *t;
 492         int count_offset, limit, count;
 493
 494         if (!ext4_has_metadata_csum(inode->i_sb))
 495                 return 1;
 496
 497         c = get_dx_countlimit(inode, dirent, &count_offset);
 498         if (!c) {
 499                 EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
 500                 return 0;
 501         }
 502         limit = le16_to_cpu(c->limit);
 503         count = le16_to_cpu(c->count);
 504         if (count_offset + (limit * sizeof(struct dx_entry)) >
 505             EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
 506                 warn_no_space_for_csum(inode);
 507                 return 0;
 508         }
 509         t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
 510
 511         if (t->dt_checksum != ext4_dx_csum(inode, dirent, count_offset,
 512                                             count, t))
 513                 return 0;
 514         return 1;
 515 }
 516
 517 static void ext4_dx_csum_set(struct inode *inode, struct ext4_dir_entry *dirent)
 518 {
 519         struct dx_countlimit *c;
 520         struct dx_tail *t;
 521         int count_offset, limit, count;
 522
 523         if (!ext4_has_metadata_csum(inode->i_sb))
 524                 return;
 525
 526         c = get_dx_countlimit(inode, dirent, &count_offset);
 527         if (!c) {
 528                 EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
 529                 return;
 530         }
 531         limit = le16_to_cpu(c->limit);
 532         count = le16_to_cpu(c->count);
 533         if (count_offset + (limit * sizeof(struct dx_entry)) >
 534             EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
 535                 warn_no_space_for_csum(inode);
 536                 return;
 537         }
 538         t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
 539
 540         t->dt_checksum = ext4_dx_csum(inode, dirent, count_offset, count, t);
 541 }
 542
 543 static inline int ext4_handle_dirty_dx_node(handle_t *handle,
 544                                             struct inode *inode,
 545                                             struct buffer_head *bh)
 546 {
 547         ext4_dx_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
 548         return ext4_handle_dirty_metadata(handle, inode, bh);
 549 }
 550
 551 /*
 552  * p is at least 6 bytes before the end of page
 553  */
 554 static inline struct ext4_dir_entry_2 *
 555 ext4_next_entry(struct ext4_dir_entry_2 *p, unsigned long blocksize)
 556 {
 557         return (struct ext4_dir_entry_2 *)((char *)p +
 558                 ext4_rec_len_from_disk(p->rec_len, blocksize));
 559 }
 560
 561 /*
 562  * Future: use high four bits of block for coalesce-on-delete flags
 563  * Mask them off for now.
 564  */
 565
 566 static inline ext4_lblk_t dx_get_block(struct dx_entry *entry)
 567 {
 568         return le32_to_cpu(entry->block) & 0x0fffffff;
 569 }
 570
 571 static inline void dx_set_block(struct dx_entry *entry, ext4_lblk_t value)
 572 {
 573         entry->block = cpu_to_le32(value);
 574 }
 575
 576 static inline unsigned dx_get_hash(struct dx_entry *entry)
 577 {
 578         return le32_to_cpu(entry->hash);
 579 }
 580
 581 static inline void dx_set_hash(struct dx_entry *entry, unsigned value)
 582 {
 583         entry->hash = cpu_to_le32(value);
 584 }
 585
 586 static inline unsigned dx_get_count(struct dx_entry *entries)
 587 {
 588         return le16_to_cpu(((struct dx_countlimit *) entries)->count);
 589 }
 590
 591 static inline unsigned dx_get_limit(struct dx_entry *entries)
 592 {
 593         return le16_to_cpu(((struct dx_countlimit *) entries)->limit);
 594 }
 595
 596 static inline void dx_set_count(struct dx_entry *entries, unsigned value)
 597 {
 598         ((struct dx_countlimit *) entries)->count = cpu_to_le16(value);
 599 }
 600
 601 static inline void dx_set_limit(struct dx_entry *entries, unsigned value)
 602 {
 603         ((struct dx_countlimit *) entries)->limit = cpu_to_le16(value);
 604 }
 605
 606 static inline unsigned dx_root_limit(struct inode *dir, unsigned infosize)
 607 {
 608         unsigned int entry_space = dir->i_sb->s_blocksize -
 609                         ext4_dir_rec_len(1, NULL) -
 610                         ext4_dir_rec_len(2, NULL) - infosize;
 611
 612         if (ext4_has_metadata_csum(dir->i_sb))
 613                 entry_space -= sizeof(struct dx_tail);
 614         return entry_space / sizeof(struct dx_entry);
 615 }
 616
 617 static inline unsigned dx_node_limit(struct inode *dir)
 618 {
 619         unsigned int entry_space = dir->i_sb->s_blocksize -
 620                         ext4_dir_rec_len(0, dir);
 621
 622         if (ext4_has_metadata_csum(dir->i_sb))
 623                 entry_space -= sizeof(struct dx_tail);
 624         return entry_space / sizeof(struct dx_entry);
 625 }
 626
 627 /*
 628  * Debug
 629  */
 630 #ifdef DX_DEBUG
 631 static void dx_show_index(char * label, struct dx_entry *entries)
 632 {
 633         int i, n = dx_get_count (entries);
 634         printk(KERN_DEBUG "%s index", label);
 635         for (i = 0; i < n; i++) {
 636                 printk(KERN_CONT " %x->%lu",
 637                        i ? dx_get_hash(entries + i) : 0,
 638                        (unsigned long)dx_get_block(entries + i));
 639         }
 640         printk(KERN_CONT "\n");
 641 }
 642
 643 struct stats
 644 {
 645         unsigned names;
 646         unsigned space;
 647         unsigned bcount;
 648 };
 649
 650 static struct stats dx_show_leaf(struct inode *dir,
 651                                 struct dx_hash_info *hinfo,
 652                                 struct ext4_dir_entry_2 *de,
 653                                 int size, int show_names)
 654 {
 655         unsigned names = 0, space = 0;
 656         char *base = (char *) de;
 657         struct dx_hash_info h = *hinfo;
 658
 659         printk("names: ");
 660         while ((char *) de < base + size)
 661         {
 662                 if (de->inode)
 663                 {
 664                         if (show_names)
 665                         {
 666 #ifdef CONFIG_FS_ENCRYPTION
 667                                 int len;
 668                                 char *name;
 669                                 struct fscrypt_str fname_crypto_str =
 670                                         FSTR_INIT(NULL, 0);
 671                                 int res = 0;
 672
 673                                 name  = de->name;
 674                                 len = de->name_len;
 675                                 if (!IS_ENCRYPTED(dir)) {
 676                                         /* Directory is not encrypted */
 677                                         ext4fs_dirhash(dir, de->name,
 678                                                 de->name_len, &h);
 679                                         printk("%*.s:(U)%x.%u ", len,
 680                                                name, h.hash,
 681                                                (unsigned) ((char *) de
 682                                                            - base));
 683                                 } else {
 684                                         struct fscrypt_str de_name =
 685                                                 FSTR_INIT(name, len);
 686
 687                                         /* Directory is encrypted */
 688                                         res = fscrypt_fname_alloc_buffer(
 689                                                 len, &fname_crypto_str);
 690                                         if (res)
 691                                                 printk(KERN_WARNING "Error "
 692                                                         "allocating crypto "
 693                                                         "buffer--skipping "
 694                                                         "crypto\n");
 695                                         res = fscrypt_fname_disk_to_usr(dir,
 696                                                 0, 0, &de_name,
 697                                                 &fname_crypto_str);
 698                                         if (res) {
 699                                                 printk(KERN_WARNING "Error "
 700                                                         "converting filename "
 701                                                         "from disk to usr"
 702                                                         "\n");
 703                                                 name = "??";
 704                                                 len = 2;
 705                                         } else {
 706                                                 name = fname_crypto_str.name;
 707                                                 len = fname_crypto_str.len;
 708                                         }
 709                                         if (IS_CASEFOLDED(dir))
 710                                                 h.hash = EXT4_DIRENT_HASH(de);
 711                                         else
 712                                                 ext4fs_dirhash(dir, de->name,
 713                                                        de->name_len, &h);
 714                                         printk("%*.s:(E)%x.%u ", len, name,
 715                                                h.hash, (unsigned) ((char *) de
 716                                                                    - base));
 717                                         fscrypt_fname_free_buffer(
 718                                                         &fname_crypto_str);
 719                                 }
 720 #else
 721                                 int len = de->name_len;
 722                                 char *name = de->name;
 723                                 ext4fs_dirhash(dir, de->name, de->name_len, &h);
 724                                 printk("%*.s:%x.%u ", len, name, h.hash,
 725                                        (unsigned) ((char *) de - base));
 726 #endif
 727                         }
 728                         space += ext4_dir_rec_len(de->name_len, dir);
 729                         names++;
 730                 }
 731                 de = ext4_next_entry(de, size);
 732         }
 733         printk(KERN_CONT "(%i)\n", names);
 734         return (struct stats) { names, space, 1 };
 735 }
 736
 737 struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir,
 738                              struct dx_entry *entries, int levels)
 739 {
 740         unsigned blocksize = dir->i_sb->s_blocksize;
 741         unsigned count = dx_get_count(entries), names = 0, space = 0, i;
 742         unsigned bcount = 0;
 743         struct buffer_head *bh;
 744         printk("%i indexed blocks...\n", count);
 745         for (i = 0; i < count; i++, entries++)
 746         {
 747                 ext4_lblk_t block = dx_get_block(entries);
 748                 ext4_lblk_t hash  = i ? dx_get_hash(entries): 0;
 749                 u32 range = i < count - 1? (dx_get_hash(entries + 1) - hash): ~hash;
 750                 struct stats stats;
 751                 printk("%s%3u:%03u hash %8x/%8x ",levels?"":"   ", i, block, hash, range);
 752                 bh = ext4_bread(NULL,dir, block, 0);
 753                 if (!bh || IS_ERR(bh))
 754                         continue;
 755                 stats = levels?
 756                    dx_show_entries(hinfo, dir, ((struct dx_node *) bh->b_data)->entries, levels - 1):
 757                    dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *)
 758                         bh->b_data, blocksize, 0);
 759                 names += stats.names;
 760                 space += stats.space;
 761                 bcount += stats.bcount;
 762                 brelse(bh);
 763         }
 764         if (bcount)
 765                 printk(KERN_DEBUG "%snames %u, fullness %u (%u%%)\n",
 766                        levels ? "" : "   ", names, space/bcount,
 767                        (space/bcount)*100/blocksize);
 768         return (struct stats) { names, space, bcount};
 769 }
 770
 771 /*
 772  * Linear search cross check
 773  */
 774 static inline void htree_rep_invariant_check(struct dx_entry *at,
 775                                              struct dx_entry *target,
 776                                              u32 hash, unsigned int n)
 777 {
 778         while (n--) {
 779                 dxtrace(printk(KERN_CONT ","));
 780                 if (dx_get_hash(++at) > hash) {
 781                         at--;
 782                         break;
 783                 }
 784         }
 785         ASSERT(at == target - 1);
 786 }
 787 #else /* DX_DEBUG */
 788 static inline void htree_rep_invariant_check(struct dx_entry *at,
 789                                              struct dx_entry *target,
 790                                              u32 hash, unsigned int n)
 791 {
 792 }
 793 #endif /* DX_DEBUG */
 794
 795 /*
 796  * Probe for a directory leaf block to search.
 797  *
 798  * dx_probe can return ERR_BAD_DX_DIR, which means there was a format
 799  * error in the directory index, and the caller should fall back to
 800  * searching the directory normally.  The callers of dx_probe **MUST**
 801  * check for this error code, and make sure it never gets reflected
 802  * back to userspace.
 803  */
 804 static struct dx_frame *
 805 dx_probe(struct ext4_filename *fname, struct inode *dir,
 806          struct dx_hash_info *hinfo, struct dx_frame *frame_in)
 807 {
 808         unsigned count, indirect, level, i;
 809         struct dx_entry *at, *entries, *p, *q, *m;
 810         struct dx_root *root;
 811         struct dx_frame *frame = frame_in;
 812         struct dx_frame *ret_err = ERR_PTR(ERR_BAD_DX_DIR);
 813         u32 hash;
 814         ext4_lblk_t block;
 815         ext4_lblk_t blocks[EXT4_HTREE_LEVEL];
 816
 817         memset(frame_in, 0, EXT4_HTREE_LEVEL * sizeof(frame_in[0]));
 818         frame->bh = ext4_read_dirblock(dir, 0, INDEX);
 819         if (IS_ERR(frame->bh))
 820                 return (struct dx_frame *) frame->bh;
 821
 822         root = (struct dx_root *) frame->bh->b_data;
 823         if (root->info.hash_version != DX_HASH_TEA &&
 824             root->info.hash_version != DX_HASH_HALF_MD4 &&
 825             root->info.hash_version != DX_HASH_LEGACY &&
 826             root->info.hash_version != DX_HASH_SIPHASH) {
 827                 ext4_warning_inode(dir, "Unrecognised inode hash code %u",
 828                                    root->info.hash_version);
 829                 goto fail;
 830         }
 831         if (ext4_hash_in_dirent(dir)) {
 832                 if (root->info.hash_version != DX_HASH_SIPHASH) {
 833                         ext4_warning_inode(dir,
 834                                 "Hash in dirent, but hash is not SIPHASH");
 835                         goto fail;
 836                 }
 837         } else {
 838                 if (root->info.hash_version == DX_HASH_SIPHASH) {
 839                         ext4_warning_inode(dir,
 840                                 "Hash code is SIPHASH, but hash not in dirent");
 841                         goto fail;
 842                 }
 843         }
 844         if (fname)
 845                 hinfo = &fname->hinfo;
 846         hinfo->hash_version = root->info.hash_version;
 847         if (hinfo->hash_version <= DX_HASH_TEA)
 848                 hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
 849         hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
 850         /* hash is already computed for encrypted casefolded directory */
 851         if (fname && fname_name(fname) &&
 852                                 !(IS_ENCRYPTED(dir) && IS_CASEFOLDED(dir)))
 853                 ext4fs_dirhash(dir, fname_name(fname), fname_len(fname), hinfo);
 854         hash = hinfo->hash;
 855
 856         if (root->info.unused_flags & 1) {
 857                 ext4_warning_inode(dir, "Unimplemented hash flags: %#06x",
 858                                    root->info.unused_flags);
 859                 goto fail;
 860         }
 861
 862         indirect = root->info.indirect_levels;
 863         if (indirect >= ext4_dir_htree_level(dir->i_sb)) {
 864                 ext4_warning(dir->i_sb,
 865                              "Directory (ino: %lu) htree depth %#06x exceed"
 866                              "supported value", dir->i_ino,
 867                              ext4_dir_htree_level(dir->i_sb));
 868                 if (ext4_dir_htree_level(dir->i_sb) < EXT4_HTREE_LEVEL) {
 869                         ext4_warning(dir->i_sb, "Enable large directory "
 870                                                 "feature to access it");
 871                 }
 872                 goto fail;
 873         }
 874
 875         entries = (struct dx_entry *)(((char *)&root->info) +
 876                                       root->info.info_length);
 877
 878         if (dx_get_limit(entries) != dx_root_limit(dir,
 879                                                    root->info.info_length)) {
 880                 ext4_warning_inode(dir, "dx entry: limit %u != root limit %u",
 881                                    dx_get_limit(entries),
 882                                    dx_root_limit(dir, root->info.info_length));
 883                 goto fail;
 884         }
 885
 886         dxtrace(printk("Look up %x", hash));
 887         level = 0;
 888         blocks[0] = 0;
 889         while (1) {
 890                 count = dx_get_count(entries);
 891                 if (!count || count > dx_get_limit(entries)) {
 892                         ext4_warning_inode(dir,
 893                                            "dx entry: count %u beyond limit %u",
 894                                            count, dx_get_limit(entries));
 895                         goto fail;
 896                 }
 897
 898                 p = entries + 1;
 899                 q = entries + count - 1;
 900                 while (p <= q) {
 901                         m = p + (q - p) / 2;
 902                         dxtrace(printk(KERN_CONT "."));
 903                         if (dx_get_hash(m) > hash)
 904                                 q = m - 1;
 905                         else
 906                                 p = m + 1;
 907                 }
 908
 909                 htree_rep_invariant_check(entries, p, hash, count - 1);
 910
 911                 at = p - 1;
 912                 dxtrace(printk(KERN_CONT " %x->%u\n",
 913                                at == entries ? 0 : dx_get_hash(at),
 914                                dx_get_block(at)));
 915                 frame->entries = entries;
 916                 frame->at = at;
 917
 918                 block = dx_get_block(at);
 919                 for (i = 0; i <= level; i++) {
 920                         if (blocks[i] == block) {
 921                                 ext4_warning_inode(dir,
 922                                         "dx entry: tree cycle block %u points back to block %u",
 923                                         blocks[level], block);
 924                                 goto fail;
 925                         }
 926                 }
 927                 if (++level > indirect)
 928                         return frame;
 929                 blocks[level] = block;
 930                 frame++;
 931                 frame->bh = ext4_read_dirblock(dir, block, INDEX);
 932                 if (IS_ERR(frame->bh)) {
 933                         ret_err = (struct dx_frame *) frame->bh;
 934                         frame->bh = NULL;
 935                         goto fail;
 936                 }
 937
 938                 entries = ((struct dx_node *) frame->bh->b_data)->entries;
 939
 940                 if (dx_get_limit(entries) != dx_node_limit(dir)) {
 941                         ext4_warning_inode(dir,
 942                                 "dx entry: limit %u != node limit %u",
 943                                 dx_get_limit(entries), dx_node_limit(dir));
 944                         goto fail;
 945                 }
 946         }
 947 fail:
 948         while (frame >= frame_in) {
 949                 brelse(frame->bh);
 950                 frame--;
 951         }
 952
 953         if (ret_err == ERR_PTR(ERR_BAD_DX_DIR))
 954                 ext4_warning_inode(dir,
 955                         "Corrupt directory, running e2fsck is recommended");
 956         return ret_err;
 957 }
 958
 959 static void dx_release(struct dx_frame *frames)
 960 {
 961         struct dx_root_info *info;
 962         int i;
 963         unsigned int indirect_levels;
 964
 965         if (frames[0].bh == NULL)
 966                 return;
 967
 968         info = &((struct dx_root *)frames[0].bh->b_data)->info;
 969         /* save local copy, "info" may be freed after brelse() */
 970         indirect_levels = info->indirect_levels;
 971         for (i = 0; i <= indirect_levels; i++) {
 972                 if (frames[i].bh == NULL)
 973                         break;
 974                 brelse(frames[i].bh);
 975                 frames[i].bh = NULL;
 976         }
 977 }
 978
 979 /*
 980  * This function increments the frame pointer to search the next leaf
 981  * block, and reads in the necessary intervening nodes if the search
 982  * should be necessary.  Whether or not the search is necessary is
 983  * controlled by the hash parameter.  If the hash value is even, then
 984  * the search is only continued if the next block starts with that
 985  * hash value.  This is used if we are searching for a specific file.
 986  *
 987  * If the hash value is HASH_NB_ALWAYS, then always go to the next block.
 988  *
 989  * This function returns 1 if the caller should continue to search,
 990  * or 0 if it should not.  If there is an error reading one of the
 991  * index blocks, it will a negative error code.
 992  *
 993  * If start_hash is non-null, it will be filled in with the starting
 994  * hash of the next page.
 995  */
 996 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
 997                                  struct dx_frame *frame,
 998                                  struct dx_frame *frames,
 999                                  __u32 *start_hash)
1000 {
1001         struct dx_frame *p;
1002         struct buffer_head *bh;
1003         int num_frames = 0;
1004         __u32 bhash;
1005
1006         p = frame;
1007         /*
1008          * Find the next leaf page by incrementing the frame pointer.
1009          * If we run out of entries in the interior node, loop around and
1010          * increment pointer in the parent node.  When we break out of
1011          * this loop, num_frames indicates the number of interior
1012          * nodes need to be read.
1013          */
1014         while (1) {
1015                 if (++(p->at) < p->entries + dx_get_count(p->entries))
1016                         break;
1017                 if (p == frames)
1018                         return 0;
1019                 num_frames++;
1020                 p--;
1021         }
1022
1023         /*
1024          * If the hash is 1, then continue only if the next page has a
1025          * continuation hash of any value.  This is used for readdir
1026          * handling.  Otherwise, check to see if the hash matches the
1027          * desired continuation hash.  If it doesn't, return since
1028          * there's no point to read in the successive index pages.
1029          */
1030         bhash = dx_get_hash(p->at);
1031         if (start_hash)
1032                 *start_hash = bhash;
1033         if ((hash & 1) == 0) {
1034                 if ((bhash & ~1) != hash)
1035                         return 0;
1036         }
1037         /*
1038          * If the hash is HASH_NB_ALWAYS, we always go to the next
1039          * block so no check is necessary
1040          */
1041         while (num_frames--) {
1042                 bh = ext4_read_dirblock(dir, dx_get_block(p->at), INDEX);
1043                 if (IS_ERR(bh))
1044                         return PTR_ERR(bh);
1045                 p++;
1046                 brelse(p->bh);
1047                 p->bh = bh;
1048                 p->at = p->entries = ((struct dx_node *) bh->b_data)->entries;
1049         }
1050         return 1;
1051 }
1052
1053
1054 /*
1055  * This function fills a red-black tree with information from a
1056  * directory block.  It returns the number directory entries loaded
1057  * into the tree.  If there is an error it is returned in err.
1058  */
1059 static int htree_dirblock_to_tree(struct file *dir_file,
1060                                   struct inode *dir, ext4_lblk_t block,
1061                                   struct dx_hash_info *hinfo,
1062                                   __u32 start_hash, __u32 start_minor_hash)
1063 {
1064         struct buffer_head *bh;
1065         struct ext4_dir_entry_2 *de, *top;
1066         int err = 0, count = 0;
1067         struct fscrypt_str fname_crypto_str = FSTR_INIT(NULL, 0), tmp_str;
1068         int csum = ext4_has_metadata_csum(dir->i_sb);
1069
1070         dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
1071                                                         (unsigned long)block));
1072         bh = ext4_read_dirblock(dir, block, DIRENT_HTREE);
1073         if (IS_ERR(bh))
1074                 return PTR_ERR(bh);
1075
1076         de = (struct ext4_dir_entry_2 *) bh->b_data;
1077         /* csum entries are not larger in the casefolded encrypted case */
1078         top = (struct ext4_dir_entry_2 *) ((char *) de +
1079                                            dir->i_sb->s_blocksize -
1080                                            ext4_dir_rec_len(0,
1081                                                            csum ? NULL : dir));
1082         /* Check if the directory is encrypted */
1083         if (IS_ENCRYPTED(dir)) {
1084                 err = fscrypt_prepare_readdir(dir);
1085                 if (err < 0) {
1086                         brelse(bh);
1087                         return err;
1088                 }
1089                 err = fscrypt_fname_alloc_buffer(EXT4_NAME_LEN,
1090                                                  &fname_crypto_str);
1091                 if (err < 0) {
1092                         brelse(bh);
1093                         return err;
1094                 }
1095         }
1096
1097         for (; de < top; de = ext4_next_entry(de, dir->i_sb->s_blocksize)) {
1098                 if (ext4_check_dir_entry(dir, NULL, de, bh,
1099                                 bh->b_data, bh->b_size,
1100                                 (block<<EXT4_BLOCK_SIZE_BITS(dir->i_sb))
1101                                          + ((char *)de - bh->b_data))) {
1102                         /* silently ignore the rest of the block */
1103                         break;
1104                 }
1105                 if (ext4_hash_in_dirent(dir)) {
1106                         if (de->name_len && de->inode) {
1107                                 hinfo->hash = EXT4_DIRENT_HASH(de);
1108                                 hinfo->minor_hash = EXT4_DIRENT_MINOR_HASH(de);
1109                         } else {
1110                                 hinfo->hash = 0;
1111                                 hinfo->minor_hash = 0;
1112                         }
1113                 } else {
1114                         ext4fs_dirhash(dir, de->name, de->name_len, hinfo);
1115                 }
1116                 if ((hinfo->hash < start_hash) ||
1117                     ((hinfo->hash == start_hash) &&
1118                      (hinfo->minor_hash < start_minor_hash)))
1119                         continue;
1120                 if (de->inode == 0)
1121                         continue;
1122                 if (!IS_ENCRYPTED(dir)) {
1123                         tmp_str.name = de->name;
1124                         tmp_str.len = de->name_len;
1125                         err = ext4_htree_store_dirent(dir_file,
1126                                    hinfo->hash, hinfo->minor_hash, de,
1127                                    &tmp_str);
1128                 } else {
1129                         int save_len = fname_crypto_str.len;
1130                         struct fscrypt_str de_name = FSTR_INIT(de->name,
1131                                                                 de->name_len);
1132
1133                         /* Directory is encrypted */
1134                         err = fscrypt_fname_disk_to_usr(dir, hinfo->hash,
1135                                         hinfo->minor_hash, &de_name,
1136                                         &fname_crypto_str);
1137                         if (err) {
1138                                 count = err;
1139                                 goto errout;
1140                         }
1141                         err = ext4_htree_store_dirent(dir_file,
1142                                    hinfo->hash, hinfo->minor_hash, de,
1143                                         &fname_crypto_str);
1144                         fname_crypto_str.len = save_len;
1145                 }
1146                 if (err != 0) {
1147                         count = err;
1148                         goto errout;
1149                 }
1150                 count++;
1151         }
1152 errout:
1153         brelse(bh);
1154         fscrypt_fname_free_buffer(&fname_crypto_str);
1155         return count;
1156 }
1157
1158
1159 /*
1160  * This function fills a red-black tree with information from a
1161  * directory.  We start scanning the directory in hash order, starting
1162  * at start_hash and start_minor_hash.
1163  *
1164  * This function returns the number of entries inserted into the tree,
1165  * or a negative error code.
1166  */
1167 int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
1168                          __u32 start_minor_hash, __u32 *next_hash)
1169 {
1170         struct dx_hash_info hinfo;
1171         struct ext4_dir_entry_2 *de;
1172         struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
1173         struct inode *dir;
1174         ext4_lblk_t block;
1175         int count = 0;
1176         int ret, err;
1177         __u32 hashval;
1178         struct fscrypt_str tmp_str;
1179
1180         dxtrace(printk(KERN_DEBUG "In htree_fill_tree, start hash: %x:%x\n",
1181                        start_hash, start_minor_hash));
1182         dir = file_inode(dir_file);
1183         if (!(ext4_test_inode_flag(dir, EXT4_INODE_INDEX))) {
1184                 if (ext4_hash_in_dirent(dir))
1185                         hinfo.hash_version = DX_HASH_SIPHASH;
1186                 else
1187                         hinfo.hash_version =
1188                                         EXT4_SB(dir->i_sb)->s_def_hash_version;
1189                 if (hinfo.hash_version <= DX_HASH_TEA)
1190                         hinfo.hash_version +=
1191                                 EXT4_SB(dir->i_sb)->s_hash_unsigned;
1192                 hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
1193                 if (ext4_has_inline_data(dir)) {
1194                         int has_inline_data = 1;
1195                         count = ext4_inlinedir_to_tree(dir_file, dir, 0,
1196                                                        &hinfo, start_hash,
1197                                                        start_minor_hash,
1198                                                        &has_inline_data);
1199                         if (has_inline_data) {
1200                                 *next_hash = ~0;
1201                                 return count;
1202                         }
1203                 }
1204                 count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
1205                                                start_hash, start_minor_hash);
1206                 *next_hash = ~0;
1207                 return count;
1208         }
1209         hinfo.hash = start_hash;
1210         hinfo.minor_hash = 0;
1211         frame = dx_probe(NULL, dir, &hinfo, frames);
1212         if (IS_ERR(frame))
1213                 return PTR_ERR(frame);
1214
1215         /* Add '.' and '..' from the htree header */
1216         if (!start_hash && !start_minor_hash) {
1217                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
1218                 tmp_str.name = de->name;
1219                 tmp_str.len = de->name_len;
1220                 err = ext4_htree_store_dirent(dir_file, 0, 0,
1221                                               de, &tmp_str);
1222                 if (err != 0)
1223                         goto errout;
1224                 count++;
1225         }
1226         if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) {
1227                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
1228                 de = ext4_next_entry(de, dir->i_sb->s_blocksize);
1229                 tmp_str.name = de->name;
1230                 tmp_str.len = de->name_len;
1231                 err = ext4_htree_store_dirent(dir_file, 2, 0,
1232                                               de, &tmp_str);
1233                 if (err != 0)
1234                         goto errout;
1235                 count++;
1236         }
1237
1238         while (1) {
1239                 if (fatal_signal_pending(current)) {
1240                         err = -ERESTARTSYS;
1241                         goto errout;
1242                 }
1243                 cond_resched();
1244                 block = dx_get_block(frame->at);
1245                 ret = htree_dirblock_to_tree(dir_file, dir, block, &hinfo,
1246                                              start_hash, start_minor_hash);
1247                 if (ret < 0) {
1248                         err = ret;
1249                         goto errout;
1250                 }
1251                 count += ret;
1252                 hashval = ~0;
1253                 ret = ext4_htree_next_block(dir, HASH_NB_ALWAYS,
1254                                             frame, frames, &hashval);
1255                 *next_hash = hashval;
1256                 if (ret < 0) {
1257                         err = ret;
1258                         goto errout;
1259                 }
1260                 /*
1261                  * Stop if:  (a) there are no more entries, or
1262                  * (b) we have inserted at least one entry and the
1263                  * next hash value is not a continuation
1264                  */
1265                 if ((ret == 0) ||
1266                     (count && ((hashval & 1) == 0)))
1267                         break;
1268         }
1269         dx_release(frames);
1270         dxtrace(printk(KERN_DEBUG "Fill tree: returned %d entries, "
1271                        "next hash: %x\n", count, *next_hash));
1272         return count;
1273 errout:
1274         dx_release(frames);
1275         return (err);
1276 }
1277
1278 static inline int search_dirblock(struct buffer_head *bh,
1279                                   struct inode *dir,
1280                                   struct ext4_filename *fname,
1281                                   unsigned int offset,
1282                                   struct ext4_dir_entry_2 **res_dir)
1283 {
1284         return ext4_search_dir(bh, bh->b_data, dir->i_sb->s_blocksize, dir,
1285                                fname, offset, res_dir);
1286 }
1287
1288 /*
1289  * Directory block splitting, compacting
1290  */
1291
1292 /*
1293  * Create map of hash values, offsets, and sizes, stored at end of block.
1294  * Returns number of entries mapped.
1295  */
1296 static int dx_make_map(struct inode *dir, struct buffer_head *bh,
1297                        struct dx_hash_info *hinfo,
1298                        struct dx_map_entry *map_tail)
1299 {
1300         int count = 0;
1301         struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)bh->b_data;
1302         unsigned int buflen = bh->b_size;
1303         char *base = bh->b_data;
1304         struct dx_hash_info h = *hinfo;
1305
1306         if (ext4_has_metadata_csum(dir->i_sb))
1307                 buflen -= sizeof(struct ext4_dir_entry_tail);
1308
1309         while ((char *) de < base + buflen) {
1310                 if (ext4_check_dir_entry(dir, NULL, de, bh, base, buflen,
1311                                          ((char *)de) - base))
1312                         return -EFSCORRUPTED;
1313                 if (de->name_len && de->inode) {
1314                         if (ext4_hash_in_dirent(dir))
1315                                 h.hash = EXT4_DIRENT_HASH(de);
1316                         else
1317                                 ext4fs_dirhash(dir, de->name, de->name_len, &h);
1318                         map_tail--;
1319                         map_tail->hash = h.hash;
1320                         map_tail->offs = ((char *) de - base)>>2;
1321                         map_tail->size = le16_to_cpu(de->rec_len);
1322                         count++;
1323                         cond_resched();
1324                 }
1325                 de = ext4_next_entry(de, dir->i_sb->s_blocksize);
1326         }
1327         return count;
1328 }
1329
1330 /* Sort map by hash value */
1331 static void dx_sort_map (struct dx_map_entry *map, unsigned count)
1332 {
1333         struct dx_map_entry *p, *q, *top = map + count - 1;
1334         int more;
1335         /* Combsort until bubble sort doesn't suck */
1336         while (count > 2) {
1337                 count = count*10/13;
1338                 if (count - 9 < 2) /* 9, 10 -> 11 */
1339                         count = 11;
1340                 for (p = top, q = p - count; q >= map; p--, q--)
1341                         if (p->hash < q->hash)
1342                                 swap(*p, *q);
1343         }
1344         /* Garden variety bubble sort */
1345         do {
1346                 more = 0;
1347                 q = top;
1348                 while (q-- > map) {
1349                         if (q[1].hash >= q[0].hash)
1350                                 continue;
1351                         swap(*(q+1), *q);
1352                         more = 1;
1353                 }
1354         } while(more);
1355 }
1356
1357 static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
1358 {
1359         struct dx_entry *entries = frame->entries;
1360         struct dx_entry *old = frame->at, *new = old + 1;
1361         int count = dx_get_count(entries);
1362
1363         ASSERT(count < dx_get_limit(entries));
1364         ASSERT(old < entries + count);
1365         memmove(new + 1, new, (char *)(entries + count) - (char *)(new));
1366         dx_set_hash(new, hash);
1367         dx_set_block(new, block);
1368         dx_set_count(entries, count + 1);
1369 }
1370
1371 #if IS_ENABLED(CONFIG_UNICODE)
1372 /*
1373  * Test whether a case-insensitive directory entry matches the filename
1374  * being searched for.  If quick is set, assume the name being looked up
1375  * is already in the casefolded form.
1376  *
1377  * Returns: 0 if the directory entry matches, more than 0 if it
1378  * doesn't match or less than zero on error.
1379  */
1380 static int ext4_ci_compare(const struct inode *parent, const struct qstr *name,
1381                            u8 *de_name, size_t de_name_len, bool quick)
1382 {
1383         const struct super_block *sb = parent->i_sb;
1384         const struct unicode_map *um = sb->s_encoding;
1385         struct fscrypt_str decrypted_name = FSTR_INIT(NULL, de_name_len);
1386         struct qstr entry = QSTR_INIT(de_name, de_name_len);
1387         int ret;
1388
1389         if (IS_ENCRYPTED(parent)) {
1390                 const struct fscrypt_str encrypted_name =
1391                                 FSTR_INIT(de_name, de_name_len);
1392
1393                 decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL);
1394                 if (!decrypted_name.name)
1395                         return -ENOMEM;
1396                 ret = fscrypt_fname_disk_to_usr(parent, 0, 0, &encrypted_name,
1397                                                 &decrypted_name);
1398                 if (ret < 0)
1399                         goto out;
1400                 entry.name = decrypted_name.name;
1401                 entry.len = decrypted_name.len;
1402         }
1403
1404         if (quick)
1405                 ret = utf8_strncasecmp_folded(um, name, &entry);
1406         else
1407                 ret = utf8_strncasecmp(um, name, &entry);
1408         if (ret < 0) {
1409                 /* Handle invalid character sequence as either an error
1410                  * or as an opaque byte sequence.
1411                  */
1412                 if (sb_has_strict_encoding(sb))
1413                         ret = -EINVAL;
1414                 else if (name->len != entry.len)
1415                         ret = 1;
1416                 else
1417                         ret = !!memcmp(name->name, entry.name, entry.len);
1418         }
1419 out:
1420         kfree(decrypted_name.name);
1421         return ret;
1422 }
1423
1424 int ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname,
1425                                   struct ext4_filename *name)
1426 {
1427         struct fscrypt_str *cf_name = &name->cf_name;
1428         struct dx_hash_info *hinfo = &name->hinfo;
1429         int len;
1430
1431         if (!IS_CASEFOLDED(dir) || !dir->i_sb->s_encoding ||
1432             (IS_ENCRYPTED(dir) && !fscrypt_has_encryption_key(dir))) {
1433                 cf_name->name = NULL;
1434                 return 0;
1435         }
1436
1437         cf_name->name = kmalloc(EXT4_NAME_LEN, GFP_NOFS);
1438         if (!cf_name->name)
1439                 return -ENOMEM;
1440
1441         len = utf8_casefold(dir->i_sb->s_encoding,
1442                             iname, cf_name->name,
1443                             EXT4_NAME_LEN);
1444         if (len <= 0) {
1445                 kfree(cf_name->name);
1446                 cf_name->name = NULL;
1447         }
1448         cf_name->len = (unsigned) len;
1449         if (!IS_ENCRYPTED(dir))
1450                 return 0;
1451
1452         hinfo->hash_version = DX_HASH_SIPHASH;
1453         hinfo->seed = NULL;
1454         if (cf_name->name)
1455                 ext4fs_dirhash(dir, cf_name->name, cf_name->len, hinfo);
1456         else
1457                 ext4fs_dirhash(dir, iname->name, iname->len, hinfo);
1458         return 0;
1459 }
1460 #endif
1461
1462 /*
1463  * Test whether a directory entry matches the filename being searched for.
1464  *
1465  * Return: %true if the directory entry matches, otherwise %false.
1466  */
1467 static bool ext4_match(struct inode *parent,
1468                               const struct ext4_filename *fname,
1469                               struct ext4_dir_entry_2 *de)
1470 {
1471         struct fscrypt_name f;
1472
1473         if (!de->inode)
1474                 return false;
1475
1476         f.usr_fname = fname->usr_fname;
1477         f.disk_name = fname->disk_name;
1478 #ifdef CONFIG_FS_ENCRYPTION
1479         f.crypto_buf = fname->crypto_buf;
1480 #endif
1481
1482 #if IS_ENABLED(CONFIG_UNICODE)
1483         if (parent->i_sb->s_encoding && IS_CASEFOLDED(parent) &&
1484             (!IS_ENCRYPTED(parent) || fscrypt_has_encryption_key(parent))) {
1485                 if (fname->cf_name.name) {
1486                         struct qstr cf = {.name = fname->cf_name.name,
1487                                           .len = fname->cf_name.len};
1488                         if (IS_ENCRYPTED(parent)) {
1489                                 if (fname->hinfo.hash != EXT4_DIRENT_HASH(de) ||
1490                                         fname->hinfo.minor_hash !=
1491                                                 EXT4_DIRENT_MINOR_HASH(de)) {
1492
1493                                         return false;
1494                                 }
1495                         }
1496                         return !ext4_ci_compare(parent, &cf, de->name,
1497                                                         de->name_len, true);
1498                 }
1499                 return !ext4_ci_compare(parent, fname->usr_fname, de->name,
1500                                                 de->name_len, false);
1501         }
1502 #endif
1503
1504         return fscrypt_match_name(&f, de->name, de->name_len);
1505 }
1506
1507 /*
1508  * Returns 0 if not found, -1 on failure, and 1 on success
1509  */
1510 int ext4_search_dir(struct buffer_head *bh, char *search_buf, int buf_size,
1511                     struct inode *dir, struct ext4_filename *fname,
1512                     unsigned int offset, struct ext4_dir_entry_2 **res_dir)
1513 {
1514         struct ext4_dir_entry_2 * de;
1515         char * dlimit;
1516         int de_len;
1517
1518         de = (struct ext4_dir_entry_2 *)search_buf;
1519         dlimit = search_buf + buf_size;
1520         while ((char *) de < dlimit - EXT4_BASE_DIR_LEN) {
1521                 /* this code is executed quadratically often */
1522                 /* do minimal checking `by hand' */
1523                 if (de->name + de->name_len <= dlimit &&
1524                     ext4_match(dir, fname, de)) {
1525                         /* found a match - just to be sure, do
1526                          * a full check */
1527                         if (ext4_check_dir_entry(dir, NULL, de, bh, search_buf,
1528                                                  buf_size, offset))
1529                                 return -1;
1530                         *res_dir = de;
1531                         return 1;
1532                 }
1533                 /* prevent looping on a bad block */
1534                 de_len = ext4_rec_len_from_disk(de->rec_len,
1535                                                 dir->i_sb->s_blocksize);
1536                 if (de_len <= 0)
1537                         return -1;
1538                 offset += de_len;
1539                 de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
1540         }
1541         return 0;
1542 }
1543
1544 static int is_dx_internal_node(struct inode *dir, ext4_lblk_t block,
1545                                struct ext4_dir_entry *de)
1546 {
1547         struct super_block *sb = dir->i_sb;
1548
1549         if (!is_dx(dir))
1550                 return 0;
1551         if (block == 0)
1552                 return 1;
1553         if (de->inode == 0 &&
1554             ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) ==
1555                         sb->s_blocksize)
1556                 return 1;
1557         return 0;
1558 }
1559
1560 /*
1561  *      __ext4_find_entry()
1562  *
1563  * finds an entry in the specified directory with the wanted name. It
1564  * returns the cache buffer in which the entry was found, and the entry
1565  * itself (as a parameter - res_dir). It does NOT read the inode of the
1566  * entry - you'll have to do that yourself if you want to.
1567  *
1568  * The returned buffer_head has ->b_count elevated.  The caller is expected
1569  * to brelse() it when appropriate.
1570  */
1571 static struct buffer_head *__ext4_find_entry(struct inode *dir,
1572                                              struct ext4_filename *fname,
1573                                              struct ext4_dir_entry_2 **res_dir,
1574                                              int *inlined)
1575 {
1576         struct super_block *sb;
1577         struct buffer_head *bh_use[NAMEI_RA_SIZE];
1578         struct buffer_head *bh, *ret = NULL;
1579         ext4_lblk_t start, block;
1580         const u8 *name = fname->usr_fname->name;
1581         size_t ra_max = 0;      /* Number of bh's in the readahead
1582                                    buffer, bh_use[] */
1583         size_t ra_ptr = 0;      /* Current index into readahead
1584                                    buffer */
1585         ext4_lblk_t  nblocks;
1586         int i, namelen, retval;
1587
1588         *res_dir = NULL;
1589         sb = dir->i_sb;
1590         namelen = fname->usr_fname->len;
1591         if (namelen > EXT4_NAME_LEN)
1592                 return NULL;
1593
1594         if (ext4_has_inline_data(dir)) {
1595                 int has_inline_data = 1;
1596                 ret = ext4_find_inline_entry(dir, fname, res_dir,
1597                                              &has_inline_data);
1598                 if (has_inline_data) {
1599                         if (inlined)
1600                                 *inlined = 1;
1601                         goto cleanup_and_exit;
1602                 }
1603         }
1604
1605         if ((namelen <= 2) && (name[0] == '.') &&
1606             (name[1] == '.' || name[1] == '\0')) {
1607                 /*
1608                  * "." or ".." will only be in the first block
1609                  * NFS may look up ".."; "." should be handled by the VFS
1610                  */
1611                 block = start = 0;
1612                 nblocks = 1;
1613                 goto restart;
1614         }
1615         if (is_dx(dir)) {
1616                 ret = ext4_dx_find_entry(dir, fname, res_dir);
1617                 /*
1618                  * On success, or if the error was file not found,
1619                  * return.  Otherwise, fall back to doing a search the
1620                  * old fashioned way.
1621                  */
1622                 if (!IS_ERR(ret) || PTR_ERR(ret) != ERR_BAD_DX_DIR)
1623                         goto cleanup_and_exit;
1624                 dxtrace(printk(KERN_DEBUG "ext4_find_entry: dx failed, "
1625                                "falling back\n"));
1626                 ret = NULL;
1627         }
1628         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1629         if (!nblocks) {
1630                 ret = NULL;
1631                 goto cleanup_and_exit;
1632         }
1633         start = EXT4_I(dir)->i_dir_start_lookup;
1634         if (start >= nblocks)
1635                 start = 0;
1636         block = start;
1637 restart:
1638         do {
1639                 /*
1640                  * We deal with the read-ahead logic here.
1641                  */
1642                 cond_resched();
1643                 if (ra_ptr >= ra_max) {
1644                         /* Refill the readahead buffer */
1645                         ra_ptr = 0;
1646                         if (block < start)
1647                                 ra_max = start - block;
1648                         else
1649                                 ra_max = nblocks - block;
1650                         ra_max = min(ra_max, ARRAY_SIZE(bh_use));
1651                         retval = ext4_bread_batch(dir, block, ra_max,
1652                                                   false /* wait */, bh_use);
1653                         if (retval) {
1654                                 ret = ERR_PTR(retval);
1655                                 ra_max = 0;
1656                                 goto cleanup_and_exit;
1657                         }
1658                 }
1659                 if ((bh = bh_use[ra_ptr++]) == NULL)
1660                         goto next;
1661                 wait_on_buffer(bh);
1662                 if (!buffer_uptodate(bh)) {
1663                         EXT4_ERROR_INODE_ERR(dir, EIO,
1664                                              "reading directory lblock %lu",
1665                                              (unsigned long) block);
1666                         brelse(bh);
1667                         ret = ERR_PTR(-EIO);
1668                         goto cleanup_and_exit;
1669                 }
1670                 if (!buffer_verified(bh) &&
1671                     !is_dx_internal_node(dir, block,
1672                                          (struct ext4_dir_entry *)bh->b_data) &&
1673                     !ext4_dirblock_csum_verify(dir, bh)) {
1674                         EXT4_ERROR_INODE_ERR(dir, EFSBADCRC,
1675                                              "checksumming directory "
1676                                              "block %lu", (unsigned long)block);
1677                         brelse(bh);
1678                         ret = ERR_PTR(-EFSBADCRC);
1679                         goto cleanup_and_exit;
1680                 }
1681                 set_buffer_verified(bh);
1682                 i = search_dirblock(bh, dir, fname,
1683                             block << EXT4_BLOCK_SIZE_BITS(sb), res_dir);
1684                 if (i == 1) {
1685                         EXT4_I(dir)->i_dir_start_lookup = block;
1686                         ret = bh;
1687                         goto cleanup_and_exit;
1688                 } else {
1689                         brelse(bh);
1690                         if (i < 0)
1691                                 goto cleanup_and_exit;
1692                 }
1693         next:
1694                 if (++block >= nblocks)
1695                         block = 0;
1696         } while (block != start);
1697
1698         /*
1699          * If the directory has grown while we were searching, then
1700          * search the last part of the directory before giving up.
1701          */
1702         block = nblocks;
1703         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1704         if (block < nblocks) {
1705                 start = 0;
1706                 goto restart;
1707         }
1708
1709 cleanup_and_exit:
1710         /* Clean up the read-ahead blocks */
1711         for (; ra_ptr < ra_max; ra_ptr++)
1712                 brelse(bh_use[ra_ptr]);
1713         return ret;
1714 }
1715
1716 static struct buffer_head *ext4_find_entry(struct inode *dir,
1717                                            const struct qstr *d_name,
1718                                            struct ext4_dir_entry_2 **res_dir,
1719                                            int *inlined)
1720 {
1721         int err;
1722         struct ext4_filename fname;
1723         struct buffer_head *bh;
1724
1725         err = ext4_fname_setup_filename(dir, d_name, 1, &fname);
1726         if (err == -ENOENT)
1727                 return NULL;
1728         if (err)
1729                 return ERR_PTR(err);
1730
1731         bh = __ext4_find_entry(dir, &fname, res_dir, inlined);
1732
1733         ext4_fname_free_filename(&fname);
1734         return bh;
1735 }
1736
1737 static struct buffer_head *ext4_lookup_entry(struct inode *dir,
1738                                              struct dentry *dentry,
1739                                              struct ext4_dir_entry_2 **res_dir)
1740 {
1741         int err;
1742         struct ext4_filename fname;
1743         struct buffer_head *bh;
1744
1745         err = ext4_fname_prepare_lookup(dir, dentry, &fname);
1746         generic_set_encrypted_ci_d_ops(dentry);
1747         if (err == -ENOENT)
1748                 return NULL;
1749         if (err)
1750                 return ERR_PTR(err);
1751
1752         bh = __ext4_find_entry(dir, &fname, res_dir, NULL);
1753
1754         ext4_fname_free_filename(&fname);
1755         return bh;
1756 }
1757
1758 static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
1759                         struct ext4_filename *fname,
1760                         struct ext4_dir_entry_2 **res_dir)
1761 {
1762         struct super_block * sb = dir->i_sb;
1763         struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
1764         struct buffer_head *bh;
1765         ext4_lblk_t block;
1766         int retval;
1767
1768 #ifdef CONFIG_FS_ENCRYPTION
1769         *res_dir = NULL;
1770 #endif
1771         frame = dx_probe(fname, dir, NULL, frames);
1772         if (IS_ERR(frame))
1773                 return (struct buffer_head *) frame;
1774         do {
1775                 block = dx_get_block(frame->at);
1776                 bh = ext4_read_dirblock(dir, block, DIRENT_HTREE);
1777                 if (IS_ERR(bh))
1778                         goto errout;
1779
1780                 retval = search_dirblock(bh, dir, fname,
1781                                          block << EXT4_BLOCK_SIZE_BITS(sb),
1782                                          res_dir);
1783                 if (retval == 1)
1784                         goto success;
1785                 brelse(bh);
1786                 if (retval == -1) {
1787                         bh = ERR_PTR(ERR_BAD_DX_DIR);
1788                         goto errout;
1789                 }
1790
1791                 /* Check to see if we should continue to search */
1792                 retval = ext4_htree_next_block(dir, fname->hinfo.hash, frame,
1793                                                frames, NULL);
1794                 if (retval < 0) {
1795                         ext4_warning_inode(dir,
1796                                 "error %d reading directory index block",
1797                                 retval);
1798                         bh = ERR_PTR(retval);
1799                         goto errout;
1800                 }
1801         } while (retval == 1);
1802
1803         bh = NULL;
1804 errout:
1805         dxtrace(printk(KERN_DEBUG "%s not found\n", fname->usr_fname->name));
1806 success:
1807         dx_release(frames);
1808         return bh;
1809 }
1810
1811 static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
1812 {
1813         struct inode *inode;
1814         struct ext4_dir_entry_2 *de;
1815         struct buffer_head *bh;
1816
1817         if (dentry->d_name.len > EXT4_NAME_LEN)
1818                 return ERR_PTR(-ENAMETOOLONG);
1819
1820         bh = ext4_lookup_entry(dir, dentry, &de);
1821         if (IS_ERR(bh))
1822                 return ERR_CAST(bh);
1823         inode = NULL;
1824         if (bh) {
1825                 __u32 ino = le32_to_cpu(de->inode);
1826                 brelse(bh);
1827                 if (!ext4_valid_inum(dir->i_sb, ino)) {
1828                         EXT4_ERROR_INODE(dir, "bad inode number: %u", ino);
1829                         return ERR_PTR(-EFSCORRUPTED);
1830                 }
1831                 if (unlikely(ino == dir->i_ino)) {
1832                         EXT4_ERROR_INODE(dir, "'%pd' linked to parent dir",
1833                                          dentry);
1834                         return ERR_PTR(-EFSCORRUPTED);
1835                 }
1836                 inode = ext4_iget(dir->i_sb, ino, EXT4_IGET_NORMAL);
1837                 if (inode == ERR_PTR(-ESTALE)) {
1838                         EXT4_ERROR_INODE(dir,
1839                                          "deleted inode referenced: %u",
1840                                          ino);
1841                         return ERR_PTR(-EFSCORRUPTED);
1842                 }
1843                 if (!IS_ERR(inode) && IS_ENCRYPTED(dir) &&
1844                     (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) &&
1845                     !fscrypt_has_permitted_context(dir, inode)) {
1846                         ext4_warning(inode->i_sb,
1847                                      "Inconsistent encryption contexts: %lu/%lu",
1848                                      dir->i_ino, inode->i_ino);
1849                         iput(inode);
1850                         return ERR_PTR(-EPERM);
1851                 }
1852         }
1853
1854 #if IS_ENABLED(CONFIG_UNICODE)
1855         if (!inode && IS_CASEFOLDED(dir)) {
1856                 /* Eventually we want to call d_add_ci(dentry, NULL)
1857                  * for negative dentries in the encoding case as
1858                  * well.  For now, prevent the negative dentry
1859                  * from being cached.
1860                  */
1861                 return NULL;
1862         }
1863 #endif
1864         return d_splice_alias(inode, dentry);
1865 }
1866
1867
1868 struct dentry *ext4_get_parent(struct dentry *child)
1869 {
1870         __u32 ino;
1871         struct ext4_dir_entry_2 * de;
1872         struct buffer_head *bh;
1873
1874         bh = ext4_find_entry(d_inode(child), &dotdot_name, &de, NULL);
1875         if (IS_ERR(bh))
1876                 return ERR_CAST(bh);
1877         if (!bh)
1878                 return ERR_PTR(-ENOENT);
1879         ino = le32_to_cpu(de->inode);
1880         brelse(bh);
1881
1882         if (!ext4_valid_inum(child->d_sb, ino)) {
1883                 EXT4_ERROR_INODE(d_inode(child),
1884                                  "bad parent inode number: %u", ino);
1885                 return ERR_PTR(-EFSCORRUPTED);
1886         }
1887
1888         return d_obtain_alias(ext4_iget(child->d_sb, ino, EXT4_IGET_NORMAL));
1889 }
1890
1891 /*
1892  * Move count entries from end of map between two memory locations.
1893  * Returns pointer to last entry moved.
1894  */
1895 static struct ext4_dir_entry_2 *
1896 dx_move_dirents(struct inode *dir, char *from, char *to,
1897                 struct dx_map_entry *map, int count,
1898                 unsigned blocksize)
1899 {
1900         unsigned rec_len = 0;
1901
1902         while (count--) {
1903                 struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)
1904                                                 (from + (map->offs<<2));
1905                 rec_len = ext4_dir_rec_len(de->name_len, dir);
1906
1907                 memcpy (to, de, rec_len);
1908                 ((struct ext4_dir_entry_2 *) to)->rec_len =
1909                                 ext4_rec_len_to_disk(rec_len, blocksize);
1910
1911                 /* wipe dir_entry excluding the rec_len field */
1912                 de->inode = 0;
1913                 memset(&de->name_len, 0, ext4_rec_len_from_disk(de->rec_len,
1914                                                                 blocksize) -
1915                                          offsetof(struct ext4_dir_entry_2,
1916                                                                 name_len));
1917
1918                 map++;
1919                 to += rec_len;
1920         }
1921         return (struct ext4_dir_entry_2 *) (to - rec_len);
1922 }
1923
1924 /*
1925  * Compact each dir entry in the range to the minimal rec_len.
1926  * Returns pointer to last entry in range.
1927  */
1928 static struct ext4_dir_entry_2 *dx_pack_dirents(struct inode *dir, char *base,
1929                                                         unsigned int blocksize)
1930 {
1931         struct ext4_dir_entry_2 *next, *to, *prev, *de = (struct ext4_dir_entry_2 *) base;
1932         unsigned rec_len = 0;
1933
1934         prev = to = de;
1935         while ((char*)de < base + blocksize) {
1936                 next = ext4_next_entry(de, blocksize);
1937                 if (de->inode && de->name_len) {
1938                         rec_len = ext4_dir_rec_len(de->name_len, dir);
1939                         if (de > to)
1940                                 memmove(to, de, rec_len);
1941                         to->rec_len = ext4_rec_len_to_disk(rec_len, blocksize);
1942                         prev = to;
1943                         to = (struct ext4_dir_entry_2 *) (((char *) to) + rec_len);
1944                 }
1945                 de = next;
1946         }
1947         return prev;
1948 }
1949
1950 /*
1951  * Split a full leaf block to make room for a new dir entry.
1952  * Allocate a new block, and move entries so that they are approx. equally full.
1953  * Returns pointer to de in block into which the new entry will be inserted.
1954  */
1955 static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
1956                         struct buffer_head **bh,struct dx_frame *frame,
1957                         struct dx_hash_info *hinfo)
1958 {
1959         unsigned blocksize = dir->i_sb->s_blocksize;
1960         unsigned continued;
1961         int count;
1962         struct buffer_head *bh2;
1963         ext4_lblk_t newblock;
1964         u32 hash2;
1965         struct dx_map_entry *map;
1966         char *data1 = (*bh)->b_data, *data2;
1967         unsigned split, move, size;
1968         struct ext4_dir_entry_2 *de = NULL, *de2;
1969         int     csum_size = 0;
1970         int     err = 0, i;
1971
1972         if (ext4_has_metadata_csum(dir->i_sb))
1973                 csum_size = sizeof(struct ext4_dir_entry_tail);
1974
1975         bh2 = ext4_append(handle, dir, &newblock);
1976         if (IS_ERR(bh2)) {
1977                 brelse(*bh);
1978                 *bh = NULL;
1979                 return (struct ext4_dir_entry_2 *) bh2;
1980         }
1981
1982         BUFFER_TRACE(*bh, "get_write_access");
1983         err = ext4_journal_get_write_access(handle, dir->i_sb, *bh,
1984                                             EXT4_JTR_NONE);
1985         if (err)
1986                 goto journal_error;
1987
1988         BUFFER_TRACE(frame->bh, "get_write_access");
1989         err = ext4_journal_get_write_access(handle, dir->i_sb, frame->bh,
1990                                             EXT4_JTR_NONE);
1991         if (err)
1992                 goto journal_error;
1993
1994         data2 = bh2->b_data;
1995
1996         /* create map in the end of data2 block */
1997         map = (struct dx_map_entry *) (data2 + blocksize);
1998         count = dx_make_map(dir, *bh, hinfo, map);
1999         if (count < 0) {
2000                 err = count;
2001                 goto journal_error;
2002         }
2003         map -= count;
2004         dx_sort_map(map, count);
2005         /* Ensure that neither split block is over half full */
2006         size = 0;
2007         move = 0;
2008         for (i = count-1; i >= 0; i--) {
2009                 /* is more than half of this entry in 2nd half of the block? */
2010                 if (size + map[i].size/2 > blocksize/2)
2011                         break;
2012                 size += map[i].size;
2013                 move++;
2014         }
2015         /*
2016          * map index at which we will split
2017          *
2018          * If the sum of active entries didn't exceed half the block size, just
2019          * split it in half by count; each resulting block will have at least
2020          * half the space free.
2021          */
2022         if (i > 0)
2023                 split = count - move;
2024         else
2025                 split = count/2;
2026
2027         hash2 = map[split].hash;
2028         continued = hash2 == map[split - 1].hash;
2029         dxtrace(printk(KERN_INFO "Split block %lu at %x, %i/%i\n",
2030                         (unsigned long)dx_get_block(frame->at),
2031                                         hash2, split, count-split));
2032
2033         /* Fancy dance to stay within two buffers */
2034         de2 = dx_move_dirents(dir, data1, data2, map + split, count - split,
2035                               blocksize);
2036         de = dx_pack_dirents(dir, data1, blocksize);
2037         de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
2038                                            (char *) de,
2039                                            blocksize);
2040         de2->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
2041                                             (char *) de2,
2042                                             blocksize);
2043         if (csum_size) {
2044                 ext4_initialize_dirent_tail(*bh, blocksize);
2045                 ext4_initialize_dirent_tail(bh2, blocksize);
2046         }
2047
2048         dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data1,
2049                         blocksize, 1));
2050         dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data2,
2051                         blocksize, 1));
2052
2053         /* Which block gets the new entry? */
2054         if (hinfo->hash >= hash2) {
2055                 swap(*bh, bh2);
2056                 de = de2;
2057         }
2058         dx_insert_block(frame, hash2 + continued, newblock);
2059         err = ext4_handle_dirty_dirblock(handle, dir, bh2);
2060         if (err)
2061                 goto journal_error;
2062         err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
2063         if (err)
2064                 goto journal_error;
2065         brelse(bh2);
2066         dxtrace(dx_show_index("frame", frame->entries));
2067         return de;
2068
2069 journal_error:
2070         brelse(*bh);
2071         brelse(bh2);
2072         *bh = NULL;
2073         ext4_std_error(dir->i_sb, err);
2074         return ERR_PTR(err);
2075 }
2076
2077 int ext4_find_dest_de(struct inode *dir, struct inode *inode,
2078                       struct buffer_head *bh,
2079                       void *buf, int buf_size,
2080                       struct ext4_filename *fname,
2081                       struct ext4_dir_entry_2 **dest_de)
2082 {
2083         struct ext4_dir_entry_2 *de;
2084         unsigned short reclen = ext4_dir_rec_len(fname_len(fname), dir);
2085         int nlen, rlen;
2086         unsigned int offset = 0;
2087         char *top;
2088
2089         de = buf;
2090         top = buf + buf_size - reclen;
2091         while ((char *) de <= top) {
2092                 if (ext4_check_dir_entry(dir, NULL, de, bh,
2093                                          buf, buf_size, offset))
2094                         return -EFSCORRUPTED;
2095                 if (ext4_match(dir, fname, de))
2096                         return -EEXIST;
2097                 nlen = ext4_dir_rec_len(de->name_len, dir);
2098                 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
2099                 if ((de->inode ? rlen - nlen : rlen) >= reclen)
2100                         break;
2101                 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
2102                 offset += rlen;
2103         }
2104         if ((char *) de > top)
2105                 return -ENOSPC;
2106
2107         *dest_de = de;
2108         return 0;
2109 }
2110
2111 void ext4_insert_dentry(struct inode *dir,
2112                         struct inode *inode,
2113                         struct ext4_dir_entry_2 *de,
2114                         int buf_size,
2115                         struct ext4_filename *fname)
2116 {
2117
2118         int nlen, rlen;
2119
2120         nlen = ext4_dir_rec_len(de->name_len, dir);
2121         rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
2122         if (de->inode) {
2123                 struct ext4_dir_entry_2 *de1 =
2124                         (struct ext4_dir_entry_2 *)((char *)de + nlen);
2125                 de1->rec_len = ext4_rec_len_to_disk(rlen - nlen, buf_size);
2126                 de->rec_len = ext4_rec_len_to_disk(nlen, buf_size);
2127                 de = de1;
2128         }
2129         de->file_type = EXT4_FT_UNKNOWN;
2130         de->inode = cpu_to_le32(inode->i_ino);
2131         ext4_set_de_type(inode->i_sb, de, inode->i_mode);
2132         de->name_len = fname_len(fname);
2133         memcpy(de->name, fname_name(fname), fname_len(fname));
2134         if (ext4_hash_in_dirent(dir)) {
2135                 struct dx_hash_info *hinfo = &fname->hinfo;
2136
2137                 EXT4_DIRENT_HASHES(de)->hash = cpu_to_le32(hinfo->hash);
2138                 EXT4_DIRENT_HASHES(de)->minor_hash =
2139                                                 cpu_to_le32(hinfo->minor_hash);
2140         }
2141 }
2142
2143 /*
2144  * Add a new entry into a directory (leaf) block.  If de is non-NULL,
2145  * it points to a directory entry which is guaranteed to be large
2146  * enough for new directory entry.  If de is NULL, then
2147  * add_dirent_to_buf will attempt search the directory block for
2148  * space.  It will return -ENOSPC if no space is available, and -EIO
2149  * and -EEXIST if directory entry already exists.
2150  */
2151 static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
2152                              struct inode *dir,
2153                              struct inode *inode, struct ext4_dir_entry_2 *de,
2154                              struct buffer_head *bh)
2155 {
2156         unsigned int    blocksize = dir->i_sb->s_blocksize;
2157         int             csum_size = 0;
2158         int             err, err2;
2159
2160         if (ext4_has_metadata_csum(inode->i_sb))
2161                 csum_size = sizeof(struct ext4_dir_entry_tail);
2162
2163         if (!de) {
2164                 err = ext4_find_dest_de(dir, inode, bh, bh->b_data,
2165                                         blocksize - csum_size, fname, &de);
2166                 if (err)
2167                         return err;
2168         }
2169         BUFFER_TRACE(bh, "get_write_access");
2170         err = ext4_journal_get_write_access(handle, dir->i_sb, bh,
2171                                             EXT4_JTR_NONE);
2172         if (err) {
2173                 ext4_std_error(dir->i_sb, err);
2174                 return err;
2175         }
2176
2177         /* By now the buffer is marked for journaling */
2178         ext4_insert_dentry(dir, inode, de, blocksize, fname);
2179
2180         /*
2181          * XXX shouldn't update any times until successful
2182          * completion of syscall, but too many callers depend
2183          * on this.
2184          *
2185          * XXX similarly, too many callers depend on
2186          * ext4_new_inode() setting the times, but error
2187          * recovery deletes the inode, so the worst that can
2188          * happen is that the times are slightly out of date
2189          * and/or different from the directory change time.
2190          */
2191         dir->i_mtime = dir->i_ctime = current_time(dir);
2192         ext4_update_dx_flag(dir);
2193         inode_inc_iversion(dir);
2194         err2 = ext4_mark_inode_dirty(handle, dir);
2195         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
2196         err = ext4_handle_dirty_dirblock(handle, dir, bh);
2197         if (err)
2198                 ext4_std_error(dir->i_sb, err);
2199         return err ? err : err2;
2200 }
2201
2202 /*
2203  * This converts a one block unindexed directory to a 3 block indexed
2204  * directory, and adds the dentry to the indexed directory.
2205  */
2206 static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
2207                             struct inode *dir,
2208                             struct inode *inode, struct buffer_head *bh)
2209 {
2210         struct buffer_head *bh2;
2211         struct dx_root  *root;
2212         struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
2213         struct dx_entry *entries;
2214         struct ext4_dir_entry_2 *de, *de2;
2215         char            *data2, *top;
2216         unsigned        len;
2217         int             retval;
2218         unsigned        blocksize;
2219         ext4_lblk_t  block;
2220         struct fake_dirent *fde;
2221         int csum_size = 0;
2222
2223         if (ext4_has_metadata_csum(inode->i_sb))
2224                 csum_size = sizeof(struct ext4_dir_entry_tail);
2225
2226         blocksize =  dir->i_sb->s_blocksize;
2227         dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino));
2228         BUFFER_TRACE(bh, "get_write_access");
2229         retval = ext4_journal_get_write_access(handle, dir->i_sb, bh,
2230                                                EXT4_JTR_NONE);
2231         if (retval) {
2232                 ext4_std_error(dir->i_sb, retval);
2233                 brelse(bh);
2234                 return retval;
2235         }
2236         root = (struct dx_root *) bh->b_data;
2237
2238         /* The 0th block becomes the root, move the dirents out */
2239         fde = &root->dotdot;
2240         de = (struct ext4_dir_entry_2 *)((char *)fde +
2241                 ext4_rec_len_from_disk(fde->rec_len, blocksize));
2242         if ((char *) de >= (((char *) root) + blocksize)) {
2243                 EXT4_ERROR_INODE(dir, "invalid rec_len for '..'");
2244                 brelse(bh);
2245                 return -EFSCORRUPTED;
2246         }
2247         len = ((char *) root) + (blocksize - csum_size) - (char *) de;
2248
2249         /* Allocate new block for the 0th block's dirents */
2250         bh2 = ext4_append(handle, dir, &block);
2251         if (IS_ERR(bh2)) {
2252                 brelse(bh);
2253                 return PTR_ERR(bh2);
2254         }
2255         ext4_set_inode_flag(dir, EXT4_INODE_INDEX);
2256         data2 = bh2->b_data;
2257
2258         memcpy(data2, de, len);
2259         memset(de, 0, len); /* wipe old data */
2260         de = (struct ext4_dir_entry_2 *) data2;
2261         top = data2 + len;
2262         while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top)
2263                 de = de2;
2264         de->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
2265                                            (char *) de, blocksize);
2266
2267         if (csum_size)
2268                 ext4_initialize_dirent_tail(bh2, blocksize);
2269
2270         /* Initialize the root; the dot dirents already exist */
2271         de = (struct ext4_dir_entry_2 *) (&root->dotdot);
2272         de->rec_len = ext4_rec_len_to_disk(
2273                         blocksize - ext4_dir_rec_len(2, NULL), blocksize);
2274         memset (&root->info, 0, sizeof(root->info));
2275         root->info.info_length = sizeof(root->info);
2276         if (ext4_hash_in_dirent(dir))
2277                 root->info.hash_version = DX_HASH_SIPHASH;
2278         else
2279                 root->info.hash_version =
2280                                 EXT4_SB(dir->i_sb)->s_def_hash_version;
2281
2282         entries = root->entries;
2283         dx_set_block(entries, 1);
2284         dx_set_count(entries, 1);
2285         dx_set_limit(entries, dx_root_limit(dir, sizeof(root->info)));
2286
2287         /* Initialize as for dx_probe */
2288         fname->hinfo.hash_version = root->info.hash_version;
2289         if (fname->hinfo.hash_version <= DX_HASH_TEA)
2290                 fname->hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
2291         fname->hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
2292
2293         /* casefolded encrypted hashes are computed on fname setup */
2294         if (!ext4_hash_in_dirent(dir))
2295                 ext4fs_dirhash(dir, fname_name(fname),
2296                                 fname_len(fname), &fname->hinfo);
2297
2298         memset(frames, 0, sizeof(frames));
2299         frame = frames;
2300         frame->entries = entries;
2301         frame->at = entries;
2302         frame->bh = bh;
2303
2304         retval = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
2305         if (retval)
2306                 goto out_frames;
2307         retval = ext4_handle_dirty_dirblock(handle, dir, bh2);
2308         if (retval)
2309                 goto out_frames;
2310
2311         de = do_split(handle,dir, &bh2, frame, &fname->hinfo);
2312         if (IS_ERR(de)) {
2313                 retval = PTR_ERR(de);
2314                 goto out_frames;
2315         }
2316
2317         retval = add_dirent_to_buf(handle, fname, dir, inode, de, bh2);
2318 out_frames:
2319         /*
2320          * Even if the block split failed, we have to properly write
2321          * out all the changes we did so far. Otherwise we can end up
2322          * with corrupted filesystem.
2323          */
2324         if (retval)
2325                 ext4_mark_inode_dirty(handle, dir);
2326         dx_release(frames);
2327         brelse(bh2);
2328         return retval;
2329 }
2330
2331 /*
2332  *      ext4_add_entry()
2333  *
2334  * adds a file entry to the specified directory, using the same
2335  * semantics as ext4_find_entry(). It returns NULL if it failed.
2336  *
2337  * NOTE!! The inode part of 'de' is left at 0 - which means you
2338  * may not sleep between calling this and putting something into
2339  * the entry, as someone else might have used it while you slept.
2340  */
2341 static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
2342                           struct inode *inode)
2343 {
2344         struct inode *dir = d_inode(dentry->d_parent);
2345         struct buffer_head *bh = NULL;
2346         struct ext4_dir_entry_2 *de;
2347         struct super_block *sb;
2348         struct ext4_filename fname;
2349         int     retval;
2350         int     dx_fallback=0;
2351         unsigned blocksize;
2352         ext4_lblk_t block, blocks;
2353         int     csum_size = 0;
2354
2355         if (ext4_has_metadata_csum(inode->i_sb))
2356                 csum_size = sizeof(struct ext4_dir_entry_tail);
2357
2358         sb = dir->i_sb;
2359         blocksize = sb->s_blocksize;
2360         if (!dentry->d_name.len)
2361                 return -EINVAL;
2362
2363         if (fscrypt_is_nokey_name(dentry))
2364                 return -ENOKEY;
2365
2366 #if IS_ENABLED(CONFIG_UNICODE)
2367         if (sb_has_strict_encoding(sb) && IS_CASEFOLDED(dir) &&
2368             sb->s_encoding && utf8_validate(sb->s_encoding, &dentry->d_name))
2369                 return -EINVAL;
2370 #endif
2371
2372         retval = ext4_fname_setup_filename(dir, &dentry->d_name, 0, &fname);
2373         if (retval)
2374                 return retval;
2375
2376         if (ext4_has_inline_data(dir)) {
2377                 retval = ext4_try_add_inline_entry(handle, &fname, dir, inode);
2378                 if (retval < 0)
2379                         goto out;
2380                 if (retval == 1) {
2381                         retval = 0;
2382                         goto out;
2383                 }
2384         }
2385
2386         if (is_dx(dir)) {
2387                 retval = ext4_dx_add_entry(handle, &fname, dir, inode);
2388                 if (!retval || (retval != ERR_BAD_DX_DIR))
2389                         goto out;
2390                 /* Can we just ignore htree data? */
2391                 if (ext4_has_metadata_csum(sb)) {
2392                         EXT4_ERROR_INODE(dir,
2393                                 "Directory has corrupted htree index.");
2394                         retval = -EFSCORRUPTED;
2395                         goto out;
2396                 }
2397                 ext4_clear_inode_flag(dir, EXT4_INODE_INDEX);
2398                 dx_fallback++;
2399                 retval = ext4_mark_inode_dirty(handle, dir);
2400                 if (unlikely(retval))
2401                         goto out;
2402         }
2403         blocks = dir->i_size >> sb->s_blocksize_bits;
2404         for (block = 0; block < blocks; block++) {
2405                 bh = ext4_read_dirblock(dir, block, DIRENT);
2406                 if (bh == NULL) {
2407                         bh = ext4_bread(handle, dir, block,
2408                                         EXT4_GET_BLOCKS_CREATE);
2409                         goto add_to_new_block;
2410                 }
2411                 if (IS_ERR(bh)) {
2412                         retval = PTR_ERR(bh);
2413                         bh = NULL;
2414                         goto out;
2415                 }
2416                 retval = add_dirent_to_buf(handle, &fname, dir, inode,
2417                                            NULL, bh);
2418                 if (retval != -ENOSPC)
2419                         goto out;
2420
2421                 if (blocks == 1 && !dx_fallback &&
2422                     ext4_has_feature_dir_index(sb)) {
2423                         retval = make_indexed_dir(handle, &fname, dir,
2424                                                   inode, bh);
2425                         bh = NULL; /* make_indexed_dir releases bh */
2426                         goto out;
2427                 }
2428                 brelse(bh);
2429         }
2430         bh = ext4_append(handle, dir, &block);
2431 add_to_new_block:
2432         if (IS_ERR(bh)) {
2433                 retval = PTR_ERR(bh);
2434                 bh = NULL;
2435                 goto out;
2436         }
2437         de = (struct ext4_dir_entry_2 *) bh->b_data;
2438         de->inode = 0;
2439         de->rec_len = ext4_rec_len_to_disk(blocksize - csum_size, blocksize);
2440
2441         if (csum_size)
2442                 ext4_initialize_dirent_tail(bh, blocksize);
2443
2444         retval = add_dirent_to_buf(handle, &fname, dir, inode, de, bh);
2445 out:
2446         ext4_fname_free_filename(&fname);
2447         brelse(bh);
2448         if (retval == 0)
2449                 ext4_set_inode_state(inode, EXT4_STATE_NEWENTRY);
2450         return retval;
2451 }
2452
2453 /*
2454  * Returns 0 for success, or a negative error value
2455  */
2456 static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
2457                              struct inode *dir, struct inode *inode)
2458 {
2459         struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
2460         struct dx_entry *entries, *at;
2461         struct buffer_head *bh;
2462         struct super_block *sb = dir->i_sb;
2463         struct ext4_dir_entry_2 *de;
2464         int restart;
2465         int err;
2466
2467 again:
2468         restart = 0;
2469         frame = dx_probe(fname, dir, NULL, frames);
2470         if (IS_ERR(frame))
2471                 return PTR_ERR(frame);
2472         entries = frame->entries;
2473         at = frame->at;
2474         bh = ext4_read_dirblock(dir, dx_get_block(frame->at), DIRENT_HTREE);
2475         if (IS_ERR(bh)) {
2476                 err = PTR_ERR(bh);
2477                 bh = NULL;
2478                 goto cleanup;
2479         }
2480
2481         BUFFER_TRACE(bh, "get_write_access");
2482         err = ext4_journal_get_write_access(handle, sb, bh, EXT4_JTR_NONE);
2483         if (err)
2484                 goto journal_error;
2485
2486         err = add_dirent_to_buf(handle, fname, dir, inode, NULL, bh);
2487         if (err != -ENOSPC)
2488                 goto cleanup;
2489
2490         err = 0;
2491         /* Block full, should compress but for now just split */
2492         dxtrace(printk(KERN_DEBUG "using %u of %u node entries\n",
2493                        dx_get_count(entries), dx_get_limit(entries)));
2494         /* Need to split index? */
2495         if (dx_get_count(entries) == dx_get_limit(entries)) {
2496                 ext4_lblk_t newblock;
2497                 int levels = frame - frames + 1;
2498                 unsigned int icount;
2499                 int add_level = 1;
2500                 struct dx_entry *entries2;
2501                 struct dx_node *node2;
2502                 struct buffer_head *bh2;
2503
2504                 while (frame > frames) {
2505                         if (dx_get_count((frame - 1)->entries) <
2506                             dx_get_limit((frame - 1)->entries)) {
2507                                 add_level = 0;
2508                                 break;
2509                         }
2510                         frame--; /* split higher index block */
2511                         at = frame->at;
2512                         entries = frame->entries;
2513                         restart = 1;
2514                 }
2515                 if (add_level && levels == ext4_dir_htree_level(sb)) {
2516                         ext4_warning(sb, "Directory (ino: %lu) index full, "
2517                                          "reach max htree level :%d",
2518                                          dir->i_ino, levels);
2519                         if (ext4_dir_htree_level(sb) < EXT4_HTREE_LEVEL) {
2520                                 ext4_warning(sb, "Large directory feature is "
2521                                                  "not enabled on this "
2522                                                  "filesystem");
2523                         }
2524                         err = -ENOSPC;
2525                         goto cleanup;
2526                 }
2527                 icount = dx_get_count(entries);
2528                 bh2 = ext4_append(handle, dir, &newblock);
2529                 if (IS_ERR(bh2)) {
2530                         err = PTR_ERR(bh2);
2531                         goto cleanup;
2532                 }
2533                 node2 = (struct dx_node *)(bh2->b_data);
2534                 entries2 = node2->entries;
2535                 memset(&node2->fake, 0, sizeof(struct fake_dirent));
2536                 node2->fake.rec_len = ext4_rec_len_to_disk(sb->s_blocksize,
2537                                                            sb->s_blocksize);
2538                 BUFFER_TRACE(frame->bh, "get_write_access");
2539                 err = ext4_journal_get_write_access(handle, sb, frame->bh,
2540                                                     EXT4_JTR_NONE);
2541                 if (err)
2542                         goto journal_error;
2543                 if (!add_level) {
2544                         unsigned icount1 = icount/2, icount2 = icount - icount1;
2545                         unsigned hash2 = dx_get_hash(entries + icount1);
2546                         dxtrace(printk(KERN_DEBUG "Split index %i/%i\n",
2547                                        icount1, icount2));
2548
2549                         BUFFER_TRACE(frame->bh, "get_write_access"); /* index root */
2550                         err = ext4_journal_get_write_access(handle, sb,
2551                                                             (frame - 1)->bh,
2552                                                             EXT4_JTR_NONE);
2553                         if (err)
2554                                 goto journal_error;
2555
2556                         memcpy((char *) entries2, (char *) (entries + icount1),
2557                                icount2 * sizeof(struct dx_entry));
2558                         dx_set_count(entries, icount1);
2559                         dx_set_count(entries2, icount2);
2560                         dx_set_limit(entries2, dx_node_limit(dir));
2561
2562                         /* Which index block gets the new entry? */
2563                         if (at - entries >= icount1) {
2564                                 frame->at = at - entries - icount1 + entries2;
2565                                 frame->entries = entries = entries2;
2566                                 swap(frame->bh, bh2);
2567                         }
2568                         dx_insert_block((frame - 1), hash2, newblock);
2569                         dxtrace(dx_show_index("node", frame->entries));
2570                         dxtrace(dx_show_index("node",
2571                                ((struct dx_node *) bh2->b_data)->entries));
2572                         err = ext4_handle_dirty_dx_node(handle, dir, bh2);
2573                         if (err)
2574                                 goto journal_error;
2575                         brelse (bh2);
2576                         err = ext4_handle_dirty_dx_node(handle, dir,
2577                                                    (frame - 1)->bh);
2578                         if (err)
2579                                 goto journal_error;
2580                         err = ext4_handle_dirty_dx_node(handle, dir,
2581                                                         frame->bh);
2582                         if (restart || err)
2583                                 goto journal_error;
2584                 } else {
2585                         struct dx_root *dxroot;
2586                         memcpy((char *) entries2, (char *) entries,
2587                                icount * sizeof(struct dx_entry));
2588                         dx_set_limit(entries2, dx_node_limit(dir));
2589
2590                         /* Set up root */
2591                         dx_set_count(entries, 1);
2592                         dx_set_block(entries + 0, newblock);
2593                         dxroot = (struct dx_root *)frames[0].bh->b_data;
2594                         dxroot->info.indirect_levels += 1;
2595                         dxtrace(printk(KERN_DEBUG
2596                                        "Creating %d level index...\n",
2597                                        dxroot->info.indirect_levels));
2598                         err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
2599                         if (err)
2600                                 goto journal_error;
2601                         err = ext4_handle_dirty_dx_node(handle, dir, bh2);
2602                         brelse(bh2);
2603                         restart = 1;
2604                         goto journal_error;
2605                 }
2606         }
2607         de = do_split(handle, dir, &bh, frame, &fname->hinfo);
2608         if (IS_ERR(de)) {
2609                 err = PTR_ERR(de);
2610                 goto cleanup;
2611         }
2612         err = add_dirent_to_buf(handle, fname, dir, inode, de, bh);
2613         goto cleanup;
2614
2615 journal_error:
2616         ext4_std_error(dir->i_sb, err); /* this is a no-op if err == 0 */
2617 cleanup:
2618         brelse(bh);
2619         dx_release(frames);
2620         /* @restart is true means htree-path has been changed, we need to
2621          * repeat dx_probe() to find out valid htree-path
2622          */
2623         if (restart && err == 0)
2624                 goto again;
2625         return err;
2626 }
2627
2628 /*
2629  * ext4_generic_delete_entry deletes a directory entry by merging it
2630  * with the previous entry
2631  */
2632 int ext4_generic_delete_entry(struct inode *dir,
2633                               struct ext4_dir_entry_2 *de_del,
2634                               struct buffer_head *bh,
2635                               void *entry_buf,
2636                               int buf_size,
2637                               int csum_size)
2638 {
2639         struct ext4_dir_entry_2 *de, *pde;
2640         unsigned int blocksize = dir->i_sb->s_blocksize;
2641         int i;
2642
2643         i = 0;
2644         pde = NULL;
2645         de = entry_buf;
2646         while (i < buf_size - csum_size) {
2647                 if (ext4_check_dir_entry(dir, NULL, de, bh,
2648                                          entry_buf, buf_size, i))
2649                         return -EFSCORRUPTED;
2650                 if (de == de_del)  {
2651                         if (pde) {
2652                                 pde->rec_len = ext4_rec_len_to_disk(
2653                                         ext4_rec_len_from_disk(pde->rec_len,
2654                                                                blocksize) +
2655                                         ext4_rec_len_from_disk(de->rec_len,
2656                                                                blocksize),
2657                                         blocksize);
2658
2659                                 /* wipe entire dir_entry */
2660                                 memset(de, 0, ext4_rec_len_from_disk(de->rec_len,
2661                                                                 blocksize));
2662                         } else {
2663                                 /* wipe dir_entry excluding the rec_len field */
2664                                 de->inode = 0;
2665                                 memset(&de->name_len, 0,
2666                                         ext4_rec_len_from_disk(de->rec_len,
2667                                                                 blocksize) -
2668                                         offsetof(struct ext4_dir_entry_2,
2669                                                                 name_len));
2670                         }
2671
2672                         inode_inc_iversion(dir);
2673                         return 0;
2674                 }
2675                 i += ext4_rec_len_from_disk(de->rec_len, blocksize);
2676                 pde = de;
2677                 de = ext4_next_entry(de, blocksize);
2678         }
2679         return -ENOENT;
2680 }
2681
2682 static int ext4_delete_entry(handle_t *handle,
2683                              struct inode *dir,
2684                              struct ext4_dir_entry_2 *de_del,
2685                              struct buffer_head *bh)
2686 {
2687         int err, csum_size = 0;
2688
2689         if (ext4_has_inline_data(dir)) {
2690                 int has_inline_data = 1;
2691                 err = ext4_delete_inline_entry(handle, dir, de_del, bh,
2692                                                &has_inline_data);
2693                 if (has_inline_data)
2694                         return err;
2695         }
2696
2697         if (ext4_has_metadata_csum(dir->i_sb))
2698                 csum_size = sizeof(struct ext4_dir_entry_tail);
2699
2700         BUFFER_TRACE(bh, "get_write_access");
2701         err = ext4_journal_get_write_access(handle, dir->i_sb, bh,
2702                                             EXT4_JTR_NONE);
2703         if (unlikely(err))
2704                 goto out;
2705
2706         err = ext4_generic_delete_entry(dir, de_del, bh, bh->b_data,
2707                                         dir->i_sb->s_blocksize, csum_size);
2708         if (err)
2709                 goto out;
2710
2711         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
2712         err = ext4_handle_dirty_dirblock(handle, dir, bh);
2713         if (unlikely(err))
2714                 goto out;
2715
2716         return 0;
2717 out:
2718         if (err != -ENOENT)
2719                 ext4_std_error(dir->i_sb, err);
2720         return err;
2721 }
2722
2723 /*
2724  * Set directory link count to 1 if nlinks > EXT4_LINK_MAX, or if nlinks == 2
2725  * since this indicates that nlinks count was previously 1 to avoid overflowing
2726  * the 16-bit i_links_count field on disk.  Directories with i_nlink == 1 mean
2727  * that subdirectory link counts are not being maintained accurately.
2728  *
2729  * The caller has already checked for i_nlink overflow in case the DIR_LINK
2730  * feature is not enabled and returned -EMLINK.  The is_dx() check is a proxy
2731  * for checking S_ISDIR(inode) (since the INODE_INDEX feature will not be set
2732  * on regular files) and to avoid creating huge/slow non-HTREE directories.
2733  */
2734 static void ext4_inc_count(struct inode *inode)
2735 {
2736         inc_nlink(inode);
2737         if (is_dx(inode) &&
2738             (inode->i_nlink > EXT4_LINK_MAX || inode->i_nlink == 2))
2739                 set_nlink(inode, 1);
2740 }
2741
2742 /*
2743  * If a directory had nlink == 1, then we should let it be 1. This indicates
2744  * directory has >EXT4_LINK_MAX subdirs.
2745  */
2746 static void ext4_dec_count(struct inode *inode)
2747 {
2748         if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
2749                 drop_nlink(inode);
2750 }
2751
2752
2753 /*
2754  * Add non-directory inode to a directory. On success, the inode reference is
2755  * consumed by dentry is instantiation. This is also indicated by clearing of
2756  * *inodep pointer. On failure, the caller is responsible for dropping the
2757  * inode reference in the safe context.
2758  */
2759 static int ext4_add_nondir(handle_t *handle,
2760                 struct dentry *dentry, struct inode **inodep)
2761 {
2762         struct inode *dir = d_inode(dentry->d_parent);
2763         struct inode *inode = *inodep;
2764         int err = ext4_add_entry(handle, dentry, inode);
2765         if (!err) {
2766                 err = ext4_mark_inode_dirty(handle, inode);
2767                 if (IS_DIRSYNC(dir))
2768                         ext4_handle_sync(handle);
2769                 d_instantiate_new(dentry, inode);
2770                 *inodep = NULL;
2771                 return err;
2772         }
2773         drop_nlink(inode);
2774         ext4_orphan_add(handle, inode);
2775         unlock_new_inode(inode);
2776         return err;
2777 }
2778
2779 /*
2780  * By the time this is called, we already have created
2781  * the directory cache entry for the new file, but it
2782  * is so far negative - it has no inode.
2783  *
2784  * If the create succeeds, we fill in the inode information
2785  * with d_instantiate().
2786  */
2787 static int ext4_create(struct user_namespace *mnt_userns, struct inode *dir,
2788                        struct dentry *dentry, umode_t mode, bool excl)
2789 {
2790         handle_t *handle;
2791         struct inode *inode;
2792         int err, credits, retries = 0;
2793
2794         err = dquot_initialize(dir);
2795         if (err)
2796                 return err;
2797
2798         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2799                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2800 retry:
2801         inode = ext4_new_inode_start_handle(mnt_userns, dir, mode, &dentry->d_name,
2802                                             0, NULL, EXT4_HT_DIR, credits);
2803         handle = ext4_journal_current_handle();
2804         err = PTR_ERR(inode);
2805         if (!IS_ERR(inode)) {
2806                 inode->i_op = &ext4_file_inode_operations;
2807                 inode->i_fop = &ext4_file_operations;
2808                 ext4_set_aops(inode);
2809                 err = ext4_add_nondir(handle, dentry, &inode);
2810                 if (!err)
2811                         ext4_fc_track_create(handle, dentry);
2812         }
2813         if (handle)
2814                 ext4_journal_stop(handle);
2815         if (!IS_ERR_OR_NULL(inode))
2816                 iput(inode);
2817         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2818                 goto retry;
2819         return err;
2820 }
2821
2822 static int ext4_mknod(struct user_namespace *mnt_userns, struct inode *dir,
2823                       struct dentry *dentry, umode_t mode, dev_t rdev)
2824 {
2825         handle_t *handle;
2826         struct inode *inode;
2827         int err, credits, retries = 0;
2828
2829         err = dquot_initialize(dir);
2830         if (err)
2831                 return err;
2832
2833         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2834                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2835 retry:
2836         inode = ext4_new_inode_start_handle(mnt_userns, dir, mode, &dentry->d_name,
2837                                             0, NULL, EXT4_HT_DIR, credits);
2838         handle = ext4_journal_current_handle();
2839         err = PTR_ERR(inode);
2840         if (!IS_ERR(inode)) {
2841                 init_special_inode(inode, inode->i_mode, rdev);
2842                 inode->i_op = &ext4_special_inode_operations;
2843                 err = ext4_add_nondir(handle, dentry, &inode);
2844                 if (!err)
2845                         ext4_fc_track_create(handle, dentry);
2846         }
2847         if (handle)
2848                 ext4_journal_stop(handle);
2849         if (!IS_ERR_OR_NULL(inode))
2850                 iput(inode);
2851         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2852                 goto retry;
2853         return err;
2854 }
2855
2856 static int ext4_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
2857                         struct file *file, umode_t mode)
2858 {
2859         handle_t *handle;
2860         struct inode *inode;
2861         int err, retries = 0;
2862
2863         err = dquot_initialize(dir);
2864         if (err)
2865                 return err;
2866
2867 retry:
2868         inode = ext4_new_inode_start_handle(mnt_userns, dir, mode,
2869                                             NULL, 0, NULL,
2870                                             EXT4_HT_DIR,
2871                         EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
2872                           4 + EXT4_XATTR_TRANS_BLOCKS);
2873         handle = ext4_journal_current_handle();
2874         err = PTR_ERR(inode);
2875         if (!IS_ERR(inode)) {
2876                 inode->i_op = &ext4_file_inode_operations;
2877                 inode->i_fop = &ext4_file_operations;
2878                 ext4_set_aops(inode);
2879                 d_tmpfile(file, inode);
2880                 err = ext4_orphan_add(handle, inode);
2881                 if (err)
2882                         goto err_unlock_inode;
2883                 mark_inode_dirty(inode);
2884                 unlock_new_inode(inode);
2885         }
2886         if (handle)
2887                 ext4_journal_stop(handle);
2888         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2889                 goto retry;
2890         return finish_open_simple(file, err);
2891 err_unlock_inode:
2892         ext4_journal_stop(handle);
2893         unlock_new_inode(inode);
2894         return err;
2895 }
2896
2897 struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
2898                           struct ext4_dir_entry_2 *de,
2899                           int blocksize, int csum_size,
2900                           unsigned int parent_ino, int dotdot_real_len)
2901 {
2902         de->inode = cpu_to_le32(inode->i_ino);
2903         de->name_len = 1;
2904         de->rec_len = ext4_rec_len_to_disk(ext4_dir_rec_len(de->name_len, NULL),
2905                                            blocksize);
2906         strcpy(de->name, ".");
2907         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2908
2909         de = ext4_next_entry(de, blocksize);
2910         de->inode = cpu_to_le32(parent_ino);
2911         de->name_len = 2;
2912         if (!dotdot_real_len)
2913                 de->rec_len = ext4_rec_len_to_disk(blocksize -
2914                                         (csum_size + ext4_dir_rec_len(1, NULL)),
2915                                         blocksize);
2916         else
2917                 de->rec_len = ext4_rec_len_to_disk(
2918                                         ext4_dir_rec_len(de->name_len, NULL),
2919                                         blocksize);
2920         strcpy(de->name, "..");
2921         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2922
2923         return ext4_next_entry(de, blocksize);
2924 }
2925
2926 int ext4_init_new_dir(handle_t *handle, struct inode *dir,
2927                              struct inode *inode)
2928 {
2929         struct buffer_head *dir_block = NULL;
2930         struct ext4_dir_entry_2 *de;
2931         ext4_lblk_t block = 0;
2932         unsigned int blocksize = dir->i_sb->s_blocksize;
2933         int csum_size = 0;
2934         int err;
2935
2936         if (ext4_has_metadata_csum(dir->i_sb))
2937                 csum_size = sizeof(struct ext4_dir_entry_tail);
2938
2939         if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2940                 err = ext4_try_create_inline_dir(handle, dir, inode);
2941                 if (err < 0 && err != -ENOSPC)
2942                         goto out;
2943                 if (!err)
2944                         goto out;
2945         }
2946
2947         inode->i_size = 0;
2948         dir_block = ext4_append(handle, inode, &block);
2949         if (IS_ERR(dir_block))
2950                 return PTR_ERR(dir_block);
2951         de = (struct ext4_dir_entry_2 *)dir_block->b_data;
2952         ext4_init_dot_dotdot(inode, de, blocksize, csum_size, dir->i_ino, 0);
2953         set_nlink(inode, 2);
2954         if (csum_size)
2955                 ext4_initialize_dirent_tail(dir_block, blocksize);
2956
2957         BUFFER_TRACE(dir_block, "call ext4_handle_dirty_metadata");
2958         err = ext4_handle_dirty_dirblock(handle, inode, dir_block);
2959         if (err)
2960                 goto out;
2961         set_buffer_verified(dir_block);
2962 out:
2963         brelse(dir_block);
2964         return err;
2965 }
2966
2967 static int ext4_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
2968                       struct dentry *dentry, umode_t mode)
2969 {
2970         handle_t *handle;
2971         struct inode *inode;
2972         int err, err2 = 0, credits, retries = 0;
2973
2974         if (EXT4_DIR_LINK_MAX(dir))
2975                 return -EMLINK;
2976
2977         err = dquot_initialize(dir);
2978         if (err)
2979                 return err;
2980
2981         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2982                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2983 retry:
2984         inode = ext4_new_inode_start_handle(mnt_userns, dir, S_IFDIR | mode,
2985                                             &dentry->d_name,
2986                                             0, NULL, EXT4_HT_DIR, credits);
2987         handle = ext4_journal_current_handle();
2988         err = PTR_ERR(inode);
2989         if (IS_ERR(inode))
2990                 goto out_stop;
2991
2992         inode->i_op = &ext4_dir_inode_operations;
2993         inode->i_fop = &ext4_dir_operations;
2994         err = ext4_init_new_dir(handle, dir, inode);
2995         if (err)
2996                 goto out_clear_inode;
2997         err = ext4_mark_inode_dirty(handle, inode);
2998         if (!err)
2999                 err = ext4_add_entry(handle, dentry, inode);
3000         if (err) {
3001 out_clear_inode:
3002                 clear_nlink(inode);
3003                 ext4_orphan_add(handle, inode);
3004                 unlock_new_inode(inode);
3005                 err2 = ext4_mark_inode_dirty(handle, inode);
3006                 if (unlikely(err2))
3007                         err = err2;
3008                 ext4_journal_stop(handle);
3009                 iput(inode);
3010                 goto out_retry;
3011         }
3012         ext4_inc_count(dir);
3013
3014         ext4_update_dx_flag(dir);
3015         err = ext4_mark_inode_dirty(handle, dir);
3016         if (err)
3017                 goto out_clear_inode;
3018         d_instantiate_new(dentry, inode);
3019         ext4_fc_track_create(handle, dentry);
3020         if (IS_DIRSYNC(dir))
3021                 ext4_handle_sync(handle);
3022
3023 out_stop:
3024         if (handle)
3025                 ext4_journal_stop(handle);
3026 out_retry:
3027         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
3028                 goto retry;
3029         return err;
3030 }
3031
3032 /*
3033  * routine to check that the specified directory is empty (for rmdir)
3034  */
3035 bool ext4_empty_dir(struct inode *inode)
3036 {
3037         unsigned int offset;
3038         struct buffer_head *bh;
3039         struct ext4_dir_entry_2 *de;
3040         struct super_block *sb;
3041
3042         if (ext4_has_inline_data(inode)) {
3043                 int has_inline_data = 1;
3044                 int ret;
3045
3046                 ret = empty_inline_dir(inode, &has_inline_data);
3047                 if (has_inline_data)
3048                         return ret;
3049         }
3050
3051         sb = inode->i_sb;
3052         if (inode->i_size < ext4_dir_rec_len(1, NULL) +
3053                                         ext4_dir_rec_len(2, NULL)) {
3054                 EXT4_ERROR_INODE(inode, "invalid size");
3055                 return false;
3056         }
3057         /* The first directory block must not be a hole,
3058          * so treat it as DIRENT_HTREE
3059          */
3060         bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE);
3061         if (IS_ERR(bh))
3062                 return false;
3063
3064         de = (struct ext4_dir_entry_2 *) bh->b_data;
3065         if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data, bh->b_size,
3066                                  0) ||
3067             le32_to_cpu(de->inode) != inode->i_ino || strcmp(".", de->name)) {
3068                 ext4_warning_inode(inode, "directory missing '.'");
3069                 brelse(bh);
3070                 return false;
3071         }
3072         offset = ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
3073         de = ext4_next_entry(de, sb->s_blocksize);
3074         if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data, bh->b_size,
3075                                  offset) ||
3076             le32_to_cpu(de->inode) == 0 || strcmp("..", de->name)) {
3077                 ext4_warning_inode(inode, "directory missing '..'");
3078                 brelse(bh);
3079                 return false;
3080         }
3081         offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
3082         while (offset < inode->i_size) {
3083                 if (!(offset & (sb->s_blocksize - 1))) {
3084                         unsigned int lblock;
3085                         brelse(bh);
3086                         lblock = offset >> EXT4_BLOCK_SIZE_BITS(sb);
3087                         bh = ext4_read_dirblock(inode, lblock, EITHER);
3088                         if (bh == NULL) {
3089                                 offset += sb->s_blocksize;
3090                                 continue;
3091                         }
3092                         if (IS_ERR(bh))
3093                                 return false;
3094                 }
3095                 de = (struct ext4_dir_entry_2 *) (bh->b_data +
3096                                         (offset & (sb->s_blocksize - 1)));
3097                 if (ext4_check_dir_entry(inode, NULL, de, bh,
3098                                          bh->b_data, bh->b_size, offset) ||
3099                     le32_to_cpu(de->inode)) {
3100                         brelse(bh);
3101                         return false;
3102                 }
3103                 offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
3104         }
3105         brelse(bh);
3106         return true;
3107 }
3108
3109 static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
3110 {
3111         int retval;
3112         struct inode *inode;
3113         struct buffer_head *bh;
3114         struct ext4_dir_entry_2 *de;
3115         handle_t *handle = NULL;
3116
3117         if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
3118                 return -EIO;
3119
3120         /* Initialize quotas before so that eventual writes go in
3121          * separate transaction */
3122         retval = dquot_initialize(dir);
3123         if (retval)
3124                 return retval;
3125         retval = dquot_initialize(d_inode(dentry));
3126         if (retval)
3127                 return retval;
3128
3129         retval = -ENOENT;
3130         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
3131         if (IS_ERR(bh))
3132                 return PTR_ERR(bh);
3133         if (!bh)
3134                 goto end_rmdir;
3135
3136         inode = d_inode(dentry);
3137
3138         retval = -EFSCORRUPTED;
3139         if (le32_to_cpu(de->inode) != inode->i_ino)
3140                 goto end_rmdir;
3141
3142         retval = -ENOTEMPTY;
3143         if (!ext4_empty_dir(inode))
3144                 goto end_rmdir;
3145
3146         handle = ext4_journal_start(dir, EXT4_HT_DIR,
3147                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
3148         if (IS_ERR(handle)) {
3149                 retval = PTR_ERR(handle);
3150                 handle = NULL;
3151                 goto end_rmdir;
3152         }
3153
3154         if (IS_DIRSYNC(dir))
3155                 ext4_handle_sync(handle);
3156
3157         retval = ext4_delete_entry(handle, dir, de, bh);
3158         if (retval)
3159                 goto end_rmdir;
3160         if (!EXT4_DIR_LINK_EMPTY(inode))
3161                 ext4_warning_inode(inode,
3162                              "empty directory '%.*s' has too many links (%u)",
3163                              dentry->d_name.len, dentry->d_name.name,
3164                              inode->i_nlink);
3165         inode_inc_iversion(inode);
3166         clear_nlink(inode);
3167         /* There's no need to set i_disksize: the fact that i_nlink is
3168          * zero will ensure that the right thing happens during any
3169          * recovery. */
3170         inode->i_size = 0;
3171         ext4_orphan_add(handle, inode);
3172         inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
3173         retval = ext4_mark_inode_dirty(handle, inode);
3174         if (retval)
3175                 goto end_rmdir;
3176         ext4_dec_count(dir);
3177         ext4_update_dx_flag(dir);
3178         ext4_fc_track_unlink(handle, dentry);
3179         retval = ext4_mark_inode_dirty(handle, dir);
3180
3181 #if IS_ENABLED(CONFIG_UNICODE)
3182         /* VFS negative dentries are incompatible with Encoding and
3183          * Case-insensitiveness. Eventually we'll want avoid
3184          * invalidating the dentries here, alongside with returning the
3185          * negative dentries at ext4_lookup(), when it is better
3186          * supported by the VFS for the CI case.
3187          */
3188         if (IS_CASEFOLDED(dir))
3189                 d_invalidate(dentry);
3190 #endif
3191
3192 end_rmdir:
3193         brelse(bh);
3194         if (handle)
3195                 ext4_journal_stop(handle);
3196         return retval;
3197 }
3198
3199 int __ext4_unlink(handle_t *handle, struct inode *dir, const struct qstr *d_name,
3200                   struct inode *inode)
3201 {
3202         int retval = -ENOENT;
3203         struct buffer_head *bh;
3204         struct ext4_dir_entry_2 *de;
3205         int skip_remove_dentry = 0;
3206
3207         bh = ext4_find_entry(dir, d_name, &de, NULL);
3208         if (IS_ERR(bh))
3209                 return PTR_ERR(bh);
3210
3211         if (!bh)
3212                 return -ENOENT;
3213
3214         if (le32_to_cpu(de->inode) != inode->i_ino) {
3215                 /*
3216                  * It's okay if we find dont find dentry which matches
3217                  * the inode. That's because it might have gotten
3218                  * renamed to a different inode number
3219                  */
3220                 if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
3221                         skip_remove_dentry = 1;
3222                 else
3223                         goto out;
3224         }
3225
3226         if (IS_DIRSYNC(dir))
3227                 ext4_handle_sync(handle);
3228
3229         if (!skip_remove_dentry) {
3230                 retval = ext4_delete_entry(handle, dir, de, bh);
3231                 if (retval)
3232                         goto out;
3233                 dir->i_ctime = dir->i_mtime = current_time(dir);
3234                 ext4_update_dx_flag(dir);
3235                 retval = ext4_mark_inode_dirty(handle, dir);
3236                 if (retval)
3237                         goto out;
3238         } else {
3239                 retval = 0;
3240         }
3241         if (inode->i_nlink == 0)
3242                 ext4_warning_inode(inode, "Deleting file '%.*s' with no links",
3243                                    d_name->len, d_name->name);
3244         else
3245                 drop_nlink(inode);
3246         if (!inode->i_nlink)
3247                 ext4_orphan_add(handle, inode);
3248         inode->i_ctime = current_time(inode);
3249         retval = ext4_mark_inode_dirty(handle, inode);
3250
3251 out:
3252         brelse(bh);
3253         return retval;
3254 }
3255
3256 static int ext4_unlink(struct inode *dir, struct dentry *dentry)
3257 {
3258         handle_t *handle;
3259         int retval;
3260
3261         if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
3262                 return -EIO;
3263
3264         trace_ext4_unlink_enter(dir, dentry);
3265         /*
3266          * Initialize quotas before so that eventual writes go
3267          * in separate transaction
3268          */
3269         retval = dquot_initialize(dir);
3270         if (retval)
3271                 goto out_trace;
3272         retval = dquot_initialize(d_inode(dentry));
3273         if (retval)
3274                 goto out_trace;
3275
3276         handle = ext4_journal_start(dir, EXT4_HT_DIR,
3277                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
3278         if (IS_ERR(handle)) {
3279                 retval = PTR_ERR(handle);
3280                 goto out_trace;
3281         }
3282
3283         retval = __ext4_unlink(handle, dir, &dentry->d_name, d_inode(dentry));
3284         if (!retval)
3285                 ext4_fc_track_unlink(handle, dentry);
3286 #if IS_ENABLED(CONFIG_UNICODE)
3287         /* VFS negative dentries are incompatible with Encoding and
3288          * Case-insensitiveness. Eventually we'll want avoid
3289          * invalidating the dentries here, alongside with returning the
3290          * negative dentries at ext4_lookup(), when it is  better
3291          * supported by the VFS for the CI case.
3292          */
3293         if (IS_CASEFOLDED(dir))
3294                 d_invalidate(dentry);
3295 #endif
3296         if (handle)
3297                 ext4_journal_stop(handle);
3298
3299 out_trace:
3300         trace_ext4_unlink_exit(dentry, retval);
3301         return retval;
3302 }
3303
3304 static int ext4_init_symlink_block(handle_t *handle, struct inode *inode,
3305                                    struct fscrypt_str *disk_link)
3306 {
3307         struct buffer_head *bh;
3308         char *kaddr;
3309         int err = 0;
3310
3311         bh = ext4_bread(handle, inode, 0, EXT4_GET_BLOCKS_CREATE);
3312         if (IS_ERR(bh))
3313                 return PTR_ERR(bh);
3314
3315         BUFFER_TRACE(bh, "get_write_access");
3316         err = ext4_journal_get_write_access(handle, inode->i_sb, bh, EXT4_JTR_NONE);
3317         if (err)
3318                 goto out;
3319
3320         kaddr = (char *)bh->b_data;
3321         memcpy(kaddr, disk_link->name, disk_link->len);
3322         inode->i_size = disk_link->len - 1;
3323         EXT4_I(inode)->i_disksize = inode->i_size;
3324         err = ext4_handle_dirty_metadata(handle, inode, bh);
3325 out:
3326         brelse(bh);
3327         return err;
3328 }
3329
3330 static int ext4_symlink(struct user_namespace *mnt_userns, struct inode *dir,
3331                         struct dentry *dentry, const char *symname)
3332 {
3333         handle_t *handle;
3334         struct inode *inode;
3335         int err, len = strlen(symname);
3336         int credits;
3337         struct fscrypt_str disk_link;
3338         int retries = 0;
3339
3340         if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
3341                 return -EIO;
3342
3343         err = fscrypt_prepare_symlink(dir, symname, len, dir->i_sb->s_blocksize,
3344                                       &disk_link);
3345         if (err)
3346                 return err;
3347
3348         err = dquot_initialize(dir);
3349         if (err)
3350                 return err;
3351
3352         /*
3353          * EXT4_INDEX_EXTRA_TRANS_BLOCKS for addition of entry into the
3354          * directory. +3 for inode, inode bitmap, group descriptor allocation.
3355          * EXT4_DATA_TRANS_BLOCKS for the data block allocation and
3356          * modification.
3357          */
3358         credits = EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3359                   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3;
3360 retry:
3361         inode = ext4_new_inode_start_handle(mnt_userns, dir, S_IFLNK|S_IRWXUGO,
3362                                             &dentry->d_name, 0, NULL,
3363                                             EXT4_HT_DIR, credits);
3364         handle = ext4_journal_current_handle();
3365         if (IS_ERR(inode)) {
3366                 if (handle)
3367                         ext4_journal_stop(handle);
3368                 err = PTR_ERR(inode);
3369                 goto out_retry;
3370         }
3371
3372         if (IS_ENCRYPTED(inode)) {
3373                 err = fscrypt_encrypt_symlink(inode, symname, len, &disk_link);
3374                 if (err)
3375                         goto err_drop_inode;
3376                 inode->i_op = &ext4_encrypted_symlink_inode_operations;
3377         } else {
3378                 if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3379                         inode->i_op = &ext4_symlink_inode_operations;
3380                 } else {
3381                         inode->i_op = &ext4_fast_symlink_inode_operations;
3382                         inode->i_link = (char *)&EXT4_I(inode)->i_data;
3383                 }
3384         }
3385
3386         if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3387                 /* alloc symlink block and fill it */
3388                 err = ext4_init_symlink_block(handle, inode, &disk_link);
3389                 if (err)
3390                         goto err_drop_inode;
3391         } else {
3392                 /* clear the extent format for fast symlink */
3393                 ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
3394                 memcpy((char *)&EXT4_I(inode)->i_data, disk_link.name,
3395                        disk_link.len);
3396                 inode->i_size = disk_link.len - 1;
3397                 EXT4_I(inode)->i_disksize = inode->i_size;
3398         }
3399         err = ext4_add_nondir(handle, dentry, &inode);
3400         if (handle)
3401                 ext4_journal_stop(handle);
3402         iput(inode);
3403         goto out_retry;
3404
3405 err_drop_inode:
3406         clear_nlink(inode);
3407         ext4_orphan_add(handle, inode);
3408         unlock_new_inode(inode);
3409         if (handle)
3410                 ext4_journal_stop(handle);
3411         iput(inode);
3412 out_retry:
3413         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
3414                 goto retry;
3415         if (disk_link.name != (unsigned char *)symname)
3416                 kfree(disk_link.name);
3417         return err;
3418 }
3419
3420 int __ext4_link(struct inode *dir, struct inode *inode, struct dentry *dentry)
3421 {
3422         handle_t *handle;
3423         int err, retries = 0;
3424 retry:
3425         handle = ext4_journal_start(dir, EXT4_HT_DIR,
3426                 (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3427                  EXT4_INDEX_EXTRA_TRANS_BLOCKS) + 1);
3428         if (IS_ERR(handle))
3429                 return PTR_ERR(handle);
3430
3431         if (IS_DIRSYNC(dir))
3432                 ext4_handle_sync(handle);
3433
3434         inode->i_ctime = current_time(inode);
3435         ext4_inc_count(inode);
3436         ihold(inode);
3437
3438         err = ext4_add_entry(handle, dentry, inode);
3439         if (!err) {
3440                 err = ext4_mark_inode_dirty(handle, inode);
3441                 /* this can happen only for tmpfile being
3442                  * linked the first time
3443                  */
3444                 if (inode->i_nlink == 1)
3445                         ext4_orphan_del(handle, inode);
3446                 d_instantiate(dentry, inode);
3447                 ext4_fc_track_link(handle, dentry);
3448         } else {
3449                 drop_nlink(inode);
3450                 iput(inode);
3451         }
3452         ext4_journal_stop(handle);
3453         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
3454                 goto retry;
3455         return err;
3456 }
3457
3458 static int ext4_link(struct dentry *old_dentry,
3459                      struct inode *dir, struct dentry *dentry)
3460 {
3461         struct inode *inode = d_inode(old_dentry);
3462         int err;
3463
3464         if (inode->i_nlink >= EXT4_LINK_MAX)
3465                 return -EMLINK;
3466
3467         err = fscrypt_prepare_link(old_dentry, dir, dentry);
3468         if (err)
3469                 return err;
3470
3471         if ((ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT)) &&
3472             (!projid_eq(EXT4_I(dir)->i_projid,
3473                         EXT4_I(old_dentry->d_inode)->i_projid)))
3474                 return -EXDEV;
3475
3476         err = dquot_initialize(dir);
3477         if (err)
3478                 return err;
3479         return __ext4_link(dir, inode, dentry);
3480 }
3481
3482 /*
3483  * Try to find buffer head where contains the parent block.
3484  * It should be the inode block if it is inlined or the 1st block
3485  * if it is a normal dir.
3486  */
3487 static struct buffer_head *ext4_get_first_dir_block(handle_t *handle,
3488                                         struct inode *inode,
3489                                         int *retval,
3490                                         struct ext4_dir_entry_2 **parent_de,
3491                                         int *inlined)
3492 {
3493         struct buffer_head *bh;
3494
3495         if (!ext4_has_inline_data(inode)) {
3496                 struct ext4_dir_entry_2 *de;
3497                 unsigned int offset;
3498
3499                 /* The first directory block must not be a hole, so
3500                  * treat it as DIRENT_HTREE
3501                  */
3502                 bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE);
3503                 if (IS_ERR(bh)) {
3504                         *retval = PTR_ERR(bh);
3505                         return NULL;
3506                 }
3507
3508                 de = (struct ext4_dir_entry_2 *) bh->b_data;
3509                 if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data,
3510                                          bh->b_size, 0) ||
3511                     le32_to_cpu(de->inode) != inode->i_ino ||
3512                     strcmp(".", de->name)) {
3513                         EXT4_ERROR_INODE(inode, "directory missing '.'");
3514                         brelse(bh);
3515                         *retval = -EFSCORRUPTED;
3516                         return NULL;
3517                 }
3518                 offset = ext4_rec_len_from_disk(de->rec_len,
3519                                                 inode->i_sb->s_blocksize);
3520                 de = ext4_next_entry(de, inode->i_sb->s_blocksize);
3521                 if (ext4_check_dir_entry(inode, NULL, de, bh, bh->b_data,
3522                                          bh->b_size, offset) ||
3523                     le32_to_cpu(de->inode) == 0 || strcmp("..", de->name)) {
3524                         EXT4_ERROR_INODE(inode, "directory missing '..'");
3525                         brelse(bh);
3526                         *retval = -EFSCORRUPTED;
3527                         return NULL;
3528                 }
3529                 *parent_de = de;
3530
3531                 return bh;
3532         }
3533
3534         *inlined = 1;
3535         return ext4_get_first_inline_block(inode, parent_de, retval);
3536 }
3537
3538 struct ext4_renament {
3539         struct inode *dir;
3540         struct dentry *dentry;
3541         struct inode *inode;
3542         bool is_dir;
3543         int dir_nlink_delta;
3544
3545         /* entry for "dentry" */
3546         struct buffer_head *bh;
3547         struct ext4_dir_entry_2 *de;
3548         int inlined;
3549
3550         /* entry for ".." in inode if it's a directory */
3551         struct buffer_head *dir_bh;
3552         struct ext4_dir_entry_2 *parent_de;
3553         int dir_inlined;
3554 };
3555
3556 static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent)
3557 {
3558         int retval;
3559
3560         ent->dir_bh = ext4_get_first_dir_block(handle, ent->inode,
3561                                               &retval, &ent->parent_de,
3562                                               &ent->dir_inlined);
3563         if (!ent->dir_bh)
3564                 return retval;
3565         if (le32_to_cpu(ent->parent_de->inode) != ent->dir->i_ino)
3566                 return -EFSCORRUPTED;
3567         BUFFER_TRACE(ent->dir_bh, "get_write_access");
3568         return ext4_journal_get_write_access(handle, ent->dir->i_sb,
3569                                              ent->dir_bh, EXT4_JTR_NONE);
3570 }
3571
3572 static int ext4_rename_dir_finish(handle_t *handle, struct ext4_renament *ent,
3573                                   unsigned dir_ino)
3574 {
3575         int retval;
3576
3577         ent->parent_de->inode = cpu_to_le32(dir_ino);
3578         BUFFER_TRACE(ent->dir_bh, "call ext4_handle_dirty_metadata");
3579         if (!ent->dir_inlined) {
3580                 if (is_dx(ent->inode)) {
3581                         retval = ext4_handle_dirty_dx_node(handle,
3582                                                            ent->inode,
3583                                                            ent->dir_bh);
3584                 } else {
3585                         retval = ext4_handle_dirty_dirblock(handle, ent->inode,
3586                                                             ent->dir_bh);
3587                 }
3588         } else {
3589                 retval = ext4_mark_inode_dirty(handle, ent->inode);
3590         }
3591         if (retval) {
3592                 ext4_std_error(ent->dir->i_sb, retval);
3593                 return retval;
3594         }
3595         return 0;
3596 }
3597
3598 static int ext4_setent(handle_t *handle, struct ext4_renament *ent,
3599                        unsigned ino, unsigned file_type)
3600 {
3601         int retval, retval2;
3602
3603         BUFFER_TRACE(ent->bh, "get write access");
3604         retval = ext4_journal_get_write_access(handle, ent->dir->i_sb, ent->bh,
3605                                                EXT4_JTR_NONE);
3606         if (retval)
3607                 return retval;
3608         ent->de->inode = cpu_to_le32(ino);
3609         if (ext4_has_feature_filetype(ent->dir->i_sb))
3610                 ent->de->file_type = file_type;
3611         inode_inc_iversion(ent->dir);
3612         ent->dir->i_ctime = ent->dir->i_mtime =
3613                 current_time(ent->dir);
3614         retval = ext4_mark_inode_dirty(handle, ent->dir);
3615         BUFFER_TRACE(ent->bh, "call ext4_handle_dirty_metadata");
3616         if (!ent->inlined) {
3617                 retval2 = ext4_handle_dirty_dirblock(handle, ent->dir, ent->bh);
3618                 if (unlikely(retval2)) {
3619                         ext4_std_error(ent->dir->i_sb, retval2);
3620                         return retval2;
3621                 }
3622         }
3623         return retval;
3624 }
3625
3626 static void ext4_resetent(handle_t *handle, struct ext4_renament *ent,
3627                           unsigned ino, unsigned file_type)
3628 {
3629         struct ext4_renament old = *ent;
3630         int retval = 0;
3631
3632         /*
3633          * old->de could have moved from under us during make indexed dir,
3634          * so the old->de may no longer valid and need to find it again
3635          * before reset old inode info.
3636          */
3637         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de, NULL);
3638         if (IS_ERR(old.bh))
3639                 retval = PTR_ERR(old.bh);
3640         if (!old.bh)
3641                 retval = -ENOENT;
3642         if (retval) {
3643                 ext4_std_error(old.dir->i_sb, retval);
3644                 return;
3645         }
3646
3647         ext4_setent(handle, &old, ino, file_type);
3648         brelse(old.bh);
3649 }
3650
3651 static int ext4_find_delete_entry(handle_t *handle, struct inode *dir,
3652                                   const struct qstr *d_name)
3653 {
3654         int retval = -ENOENT;
3655         struct buffer_head *bh;
3656         struct ext4_dir_entry_2 *de;
3657
3658         bh = ext4_find_entry(dir, d_name, &de, NULL);
3659         if (IS_ERR(bh))
3660                 return PTR_ERR(bh);
3661         if (bh) {
3662                 retval = ext4_delete_entry(handle, dir, de, bh);
3663                 brelse(bh);
3664         }
3665         return retval;
3666 }
3667
3668 static void ext4_rename_delete(handle_t *handle, struct ext4_renament *ent,
3669                                int force_reread)
3670 {
3671         int retval;
3672         /*
3673          * ent->de could have moved from under us during htree split, so make
3674          * sure that we are deleting the right entry.  We might also be pointing
3675          * to a stale entry in the unused part of ent->bh so just checking inum
3676          * and the name isn't enough.
3677          */
3678         if (le32_to_cpu(ent->de->inode) != ent->inode->i_ino ||
3679             ent->de->name_len != ent->dentry->d_name.len ||
3680             strncmp(ent->de->name, ent->dentry->d_name.name,
3681                     ent->de->name_len) ||
3682             force_reread) {
3683                 retval = ext4_find_delete_entry(handle, ent->dir,
3684                                                 &ent->dentry->d_name);
3685         } else {
3686                 retval = ext4_delete_entry(handle, ent->dir, ent->de, ent->bh);
3687                 if (retval == -ENOENT) {
3688                         retval = ext4_find_delete_entry(handle, ent->dir,
3689                                                         &ent->dentry->d_name);
3690                 }
3691         }
3692
3693         if (retval) {
3694                 ext4_warning_inode(ent->dir,
3695                                    "Deleting old file: nlink %d, error=%d",
3696                                    ent->dir->i_nlink, retval);
3697         }
3698 }
3699
3700 static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
3701 {
3702         if (ent->dir_nlink_delta) {
3703                 if (ent->dir_nlink_delta == -1)
3704                         ext4_dec_count(ent->dir);
3705                 else
3706                         ext4_inc_count(ent->dir);
3707                 ext4_mark_inode_dirty(handle, ent->dir);
3708         }
3709 }
3710
3711 static struct inode *ext4_whiteout_for_rename(struct user_namespace *mnt_userns,
3712                                               struct ext4_renament *ent,
3713                                               int credits, handle_t **h)
3714 {
3715         struct inode *wh;
3716         handle_t *handle;
3717         int retries = 0;
3718
3719         /*
3720          * for inode block, sb block, group summaries,
3721          * and inode bitmap
3722          */
3723         credits += (EXT4_MAXQUOTAS_TRANS_BLOCKS(ent->dir->i_sb) +
3724                     EXT4_XATTR_TRANS_BLOCKS + 4);
3725 retry:
3726         wh = ext4_new_inode_start_handle(mnt_userns, ent->dir,
3727                                          S_IFCHR | WHITEOUT_MODE,
3728                                          &ent->dentry->d_name, 0, NULL,
3729                                          EXT4_HT_DIR, credits);
3730
3731         handle = ext4_journal_current_handle();
3732         if (IS_ERR(wh)) {
3733                 if (handle)
3734                         ext4_journal_stop(handle);
3735                 if (PTR_ERR(wh) == -ENOSPC &&
3736                     ext4_should_retry_alloc(ent->dir->i_sb, &retries))
3737                         goto retry;
3738         } else {
3739                 *h = handle;
3740                 init_special_inode(wh, wh->i_mode, WHITEOUT_DEV);
3741                 wh->i_op = &ext4_special_inode_operations;
3742         }
3743         return wh;
3744 }
3745
3746 /*
3747  * Anybody can rename anything with this: the permission checks are left to the
3748  * higher-level routines.
3749  *
3750  * n.b.  old_{dentry,inode) refers to the source dentry/inode
3751  * while new_{dentry,inode) refers to the destination dentry/inode
3752  * This comes from rename(const char *oldpath, const char *newpath)
3753  */
3754 static int ext4_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
3755                        struct dentry *old_dentry, struct inode *new_dir,
3756                        struct dentry *new_dentry, unsigned int flags)
3757 {
3758         handle_t *handle = NULL;
3759         struct ext4_renament old = {
3760                 .dir = old_dir,
3761                 .dentry = old_dentry,
3762                 .inode = d_inode(old_dentry),
3763         };
3764         struct ext4_renament new = {
3765                 .dir = new_dir,
3766                 .dentry = new_dentry,
3767                 .inode = d_inode(new_dentry),
3768         };
3769         int force_reread;
3770         int retval;
3771         struct inode *whiteout = NULL;
3772         int credits;
3773         u8 old_file_type;
3774
3775         if (new.inode && new.inode->i_nlink == 0) {
3776                 EXT4_ERROR_INODE(new.inode,
3777                                  "target of rename is already freed");
3778                 return -EFSCORRUPTED;
3779         }
3780
3781         if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT)) &&
3782             (!projid_eq(EXT4_I(new_dir)->i_projid,
3783                         EXT4_I(old_dentry->d_inode)->i_projid)))
3784                 return -EXDEV;
3785
3786         retval = dquot_initialize(old.dir);
3787         if (retval)
3788                 return retval;
3789         retval = dquot_initialize(new.dir);
3790         if (retval)
3791                 return retval;
3792
3793         /* Initialize quotas before so that eventual writes go
3794          * in separate transaction */
3795         if (new.inode) {
3796                 retval = dquot_initialize(new.inode);
3797                 if (retval)
3798                         return retval;
3799         }
3800
3801         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de, NULL);
3802         if (IS_ERR(old.bh))
3803                 return PTR_ERR(old.bh);
3804         /*
3805          *  Check for inode number is _not_ due to possible IO errors.
3806          *  We might rmdir the source, keep it as pwd of some process
3807          *  and merrily kill the link to whatever was created under the
3808          *  same name. Goodbye sticky bit ;-<
3809          */
3810         retval = -ENOENT;
3811         if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3812                 goto release_bh;
3813
3814         new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3815                                  &new.de, &new.inlined);
3816         if (IS_ERR(new.bh)) {
3817                 retval = PTR_ERR(new.bh);
3818                 new.bh = NULL;
3819                 goto release_bh;
3820         }
3821         if (new.bh) {
3822                 if (!new.inode) {
3823                         brelse(new.bh);
3824                         new.bh = NULL;
3825                 }
3826         }
3827         if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC))
3828                 ext4_alloc_da_blocks(old.inode);
3829
3830         credits = (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3831                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2);
3832         if (!(flags & RENAME_WHITEOUT)) {
3833                 handle = ext4_journal_start(old.dir, EXT4_HT_DIR, credits);
3834                 if (IS_ERR(handle)) {
3835                         retval = PTR_ERR(handle);
3836                         goto release_bh;
3837                 }
3838         } else {
3839                 whiteout = ext4_whiteout_for_rename(mnt_userns, &old, credits, &handle);
3840                 if (IS_ERR(whiteout)) {
3841                         retval = PTR_ERR(whiteout);
3842                         goto release_bh;
3843                 }
3844         }
3845
3846         old_file_type = old.de->file_type;
3847         if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3848                 ext4_handle_sync(handle);
3849
3850         if (S_ISDIR(old.inode->i_mode)) {
3851                 if (new.inode) {
3852                         retval = -ENOTEMPTY;
3853                         if (!ext4_empty_dir(new.inode))
3854                                 goto end_rename;
3855                 } else {
3856                         retval = -EMLINK;
3857                         if (new.dir != old.dir && EXT4_DIR_LINK_MAX(new.dir))
3858                                 goto end_rename;
3859                 }
3860                 retval = ext4_rename_dir_prepare(handle, &old);
3861                 if (retval)
3862                         goto end_rename;
3863         }
3864         /*
3865          * If we're renaming a file within an inline_data dir and adding or
3866          * setting the new dirent causes a conversion from inline_data to
3867          * extents/blockmap, we need to force the dirent delete code to
3868          * re-read the directory, or else we end up trying to delete a dirent
3869          * from what is now the extent tree root (or a block map).
3870          */
3871         force_reread = (new.dir->i_ino == old.dir->i_ino &&
3872                         ext4_test_inode_flag(new.dir, EXT4_INODE_INLINE_DATA));
3873
3874         if (whiteout) {
3875                 /*
3876                  * Do this before adding a new entry, so the old entry is sure
3877                  * to be still pointing to the valid old entry.
3878                  */
3879                 retval = ext4_setent(handle, &old, whiteout->i_ino,
3880                                      EXT4_FT_CHRDEV);
3881                 if (retval)
3882                         goto end_rename;
3883                 retval = ext4_mark_inode_dirty(handle, whiteout);
3884                 if (unlikely(retval))
3885                         goto end_rename;
3886
3887         }
3888         if (!new.bh) {
3889                 retval = ext4_add_entry(handle, new.dentry, old.inode);
3890                 if (retval)
3891                         goto end_rename;
3892         } else {
3893                 retval = ext4_setent(handle, &new,
3894                                      old.inode->i_ino, old_file_type);
3895                 if (retval)
3896                         goto end_rename;
3897         }
3898         if (force_reread)
3899                 force_reread = !ext4_test_inode_flag(new.dir,
3900                                                      EXT4_INODE_INLINE_DATA);
3901
3902         /*
3903          * Like most other Unix systems, set the ctime for inodes on a
3904          * rename.
3905          */
3906         old.inode->i_ctime = current_time(old.inode);
3907         retval = ext4_mark_inode_dirty(handle, old.inode);
3908         if (unlikely(retval))
3909                 goto end_rename;
3910
3911         if (!whiteout) {
3912                 /*
3913                  * ok, that's it
3914                  */
3915                 ext4_rename_delete(handle, &old, force_reread);
3916         }
3917
3918         if (new.inode) {
3919                 ext4_dec_count(new.inode);
3920                 new.inode->i_ctime = current_time(new.inode);
3921         }
3922         old.dir->i_ctime = old.dir->i_mtime = current_time(old.dir);
3923         ext4_update_dx_flag(old.dir);
3924         if (old.dir_bh) {
3925                 retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
3926                 if (retval)
3927                         goto end_rename;
3928
3929                 ext4_dec_count(old.dir);
3930                 if (new.inode) {
3931                         /* checked ext4_empty_dir above, can't have another
3932                          * parent, ext4_dec_count() won't work for many-linked
3933                          * dirs */
3934                         clear_nlink(new.inode);
3935                 } else {
3936                         ext4_inc_count(new.dir);
3937                         ext4_update_dx_flag(new.dir);
3938                         retval = ext4_mark_inode_dirty(handle, new.dir);
3939                         if (unlikely(retval))
3940                                 goto end_rename;
3941                 }
3942         }
3943         retval = ext4_mark_inode_dirty(handle, old.dir);
3944         if (unlikely(retval))
3945                 goto end_rename;
3946
3947         if (S_ISDIR(old.inode->i_mode)) {
3948                 /*
3949                  * We disable fast commits here that's because the
3950                  * replay code is not yet capable of changing dot dot
3951                  * dirents in directories.
3952                  */
3953                 ext4_fc_mark_ineligible(old.inode->i_sb,
3954                         EXT4_FC_REASON_RENAME_DIR, handle);
3955         } else {
3956                 struct super_block *sb = old.inode->i_sb;
3957
3958                 if (new.inode)
3959                         ext4_fc_track_unlink(handle, new.dentry);
3960                 if (test_opt2(sb, JOURNAL_FAST_COMMIT) &&
3961                     !(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY) &&
3962                     !(ext4_test_mount_flag(sb, EXT4_MF_FC_INELIGIBLE))) {
3963                         __ext4_fc_track_link(handle, old.inode, new.dentry);
3964                         __ext4_fc_track_unlink(handle, old.inode, old.dentry);
3965                         if (whiteout)
3966                                 __ext4_fc_track_create(handle, whiteout,
3967                                                        old.dentry);
3968                 }
3969         }
3970
3971         if (new.inode) {
3972                 retval = ext4_mark_inode_dirty(handle, new.inode);
3973                 if (unlikely(retval))
3974                         goto end_rename;
3975                 if (!new.inode->i_nlink)
3976                         ext4_orphan_add(handle, new.inode);
3977         }
3978         retval = 0;
3979
3980 end_rename:
3981         if (whiteout) {
3982                 if (retval) {
3983                         ext4_resetent(handle, &old,
3984                                       old.inode->i_ino, old_file_type);
3985                         drop_nlink(whiteout);
3986                         ext4_orphan_add(handle, whiteout);
3987                 }
3988                 unlock_new_inode(whiteout);
3989                 ext4_journal_stop(handle);
3990                 iput(whiteout);
3991         } else {
3992                 ext4_journal_stop(handle);
3993         }
3994 release_bh:
3995         brelse(old.dir_bh);
3996         brelse(old.bh);
3997         brelse(new.bh);
3998         return retval;
3999 }
4000
4001 static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
4002                              struct inode *new_dir, struct dentry *new_dentry)
4003 {
4004         handle_t *handle = NULL;
4005         struct ext4_renament old = {
4006                 .dir = old_dir,
4007                 .dentry = old_dentry,
4008                 .inode = d_inode(old_dentry),
4009         };
4010         struct ext4_renament new = {
4011                 .dir = new_dir,
4012                 .dentry = new_dentry,
4013                 .inode = d_inode(new_dentry),
4014         };
4015         u8 new_file_type;
4016         int retval;
4017         struct timespec64 ctime;
4018
4019         if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT) &&
4020              !projid_eq(EXT4_I(new_dir)->i_projid,
4021                         EXT4_I(old_dentry->d_inode)->i_projid)) ||
4022             (ext4_test_inode_flag(old_dir, EXT4_INODE_PROJINHERIT) &&
4023              !projid_eq(EXT4_I(old_dir)->i_projid,
4024                         EXT4_I(new_dentry->d_inode)->i_projid)))
4025                 return -EXDEV;
4026
4027         retval = dquot_initialize(old.dir);
4028         if (retval)
4029                 return retval;
4030         retval = dquot_initialize(new.dir);
4031         if (retval)
4032                 return retval;
4033
4034         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name,
4035                                  &old.de, &old.inlined);
4036         if (IS_ERR(old.bh))
4037                 return PTR_ERR(old.bh);
4038         /*
4039          *  Check for inode number is _not_ due to possible IO errors.
4040          *  We might rmdir the source, keep it as pwd of some process
4041          *  and merrily kill the link to whatever was created under the
4042          *  same name. Goodbye sticky bit ;-<
4043          */
4044         retval = -ENOENT;
4045         if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
4046                 goto end_rename;
4047
4048         new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
4049                                  &new.de, &new.inlined);
4050         if (IS_ERR(new.bh)) {
4051                 retval = PTR_ERR(new.bh);
4052                 new.bh = NULL;
4053                 goto end_rename;
4054         }
4055
4056         /* RENAME_EXCHANGE case: old *and* new must both exist */
4057         if (!new.bh || le32_to_cpu(new.de->inode) != new.inode->i_ino)
4058                 goto end_rename;
4059
4060         handle = ext4_journal_start(old.dir, EXT4_HT_DIR,
4061                 (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
4062                  2 * EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));
4063         if (IS_ERR(handle)) {
4064                 retval = PTR_ERR(handle);
4065                 handle = NULL;
4066                 goto end_rename;
4067         }
4068
4069         if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
4070                 ext4_handle_sync(handle);
4071
4072         if (S_ISDIR(old.inode->i_mode)) {
4073                 old.is_dir = true;
4074                 retval = ext4_rename_dir_prepare(handle, &old);
4075                 if (retval)
4076                         goto end_rename;
4077         }
4078         if (S_ISDIR(new.inode->i_mode)) {
4079                 new.is_dir = true;
4080                 retval = ext4_rename_dir_prepare(handle, &new);
4081                 if (retval)
4082                         goto end_rename;
4083         }
4084
4085         /*
4086          * Other than the special case of overwriting a directory, parents'
4087          * nlink only needs to be modified if this is a cross directory rename.
4088          */
4089         if (old.dir != new.dir && old.is_dir != new.is_dir) {
4090                 old.dir_nlink_delta = old.is_dir ? -1 : 1;
4091                 new.dir_nlink_delta = -old.dir_nlink_delta;
4092                 retval = -EMLINK;
4093                 if ((old.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(old.dir)) ||
4094                     (new.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(new.dir)))
4095                         goto end_rename;
4096         }
4097
4098         new_file_type = new.de->file_type;
4099         retval = ext4_setent(handle, &new, old.inode->i_ino, old.de->file_type);
4100         if (retval)
4101                 goto end_rename;
4102
4103         retval = ext4_setent(handle, &old, new.inode->i_ino, new_file_type);
4104         if (retval)
4105                 goto end_rename;
4106
4107         /*
4108          * Like most other Unix systems, set the ctime for inodes on a
4109          * rename.
4110          */
4111         ctime = current_time(old.inode);
4112         old.inode->i_ctime = ctime;
4113         new.inode->i_ctime = ctime;
4114         retval = ext4_mark_inode_dirty(handle, old.inode);
4115         if (unlikely(retval))
4116                 goto end_rename;
4117         retval = ext4_mark_inode_dirty(handle, new.inode);
4118         if (unlikely(retval))
4119                 goto end_rename;
4120         ext4_fc_mark_ineligible(new.inode->i_sb,
4121                                 EXT4_FC_REASON_CROSS_RENAME, handle);
4122         if (old.dir_bh) {
4123                 retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
4124                 if (retval)
4125                         goto end_rename;
4126         }
4127         if (new.dir_bh) {
4128                 retval = ext4_rename_dir_finish(handle, &new, old.dir->i_ino);
4129                 if (retval)
4130                         goto end_rename;
4131         }
4132         ext4_update_dir_count(handle, &old);
4133         ext4_update_dir_count(handle, &new);
4134         retval = 0;
4135
4136 end_rename:
4137         brelse(old.dir_bh);
4138         brelse(new.dir_bh);
4139         brelse(old.bh);
4140         brelse(new.bh);
4141         if (handle)
4142                 ext4_journal_stop(handle);
4143         return retval;
4144 }
4145
4146 static int ext4_rename2(struct user_namespace *mnt_userns,
4147                         struct inode *old_dir, struct dentry *old_dentry,
4148                         struct inode *new_dir, struct dentry *new_dentry,
4149                         unsigned int flags)
4150 {
4151         int err;
4152
4153         if (unlikely(ext4_forced_shutdown(EXT4_SB(old_dir->i_sb))))
4154                 return -EIO;
4155
4156         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
4157                 return -EINVAL;
4158
4159         err = fscrypt_prepare_rename(old_dir, old_dentry, new_dir, new_dentry,
4160                                      flags);
4161         if (err)
4162                 return err;
4163
4164         if (flags & RENAME_EXCHANGE) {
4165                 return ext4_cross_rename(old_dir, old_dentry,
4166                                          new_dir, new_dentry);
4167         }
4168
4169         return ext4_rename(mnt_userns, old_dir, old_dentry, new_dir, new_dentry, flags);
4170 }
4171
4172 /*
4173  * directories can handle most operations...
4174  */
4175 const struct inode_operations ext4_dir_inode_operations = {
4176         .create         = ext4_create,
4177         .lookup         = ext4_lookup,
4178         .link           = ext4_link,
4179         .unlink         = ext4_unlink,
4180         .symlink        = ext4_symlink,
4181         .mkdir          = ext4_mkdir,
4182         .rmdir          = ext4_rmdir,
4183         .mknod          = ext4_mknod,
4184         .tmpfile        = ext4_tmpfile,
4185         .rename         = ext4_rename2,
4186         .setattr        = ext4_setattr,
4187         .getattr        = ext4_getattr,
4188         .listxattr      = ext4_listxattr,
4189         .get_acl        = ext4_get_acl,
4190         .set_acl        = ext4_set_acl,
4191         .fiemap         = ext4_fiemap,
4192         .fileattr_get   = ext4_fileattr_get,
4193         .fileattr_set   = ext4_fileattr_set,
4194 };
4195
4196 const struct inode_operations ext4_special_inode_operations = {
4197         .setattr        = ext4_setattr,
4198         .getattr        = ext4_getattr,
4199         .listxattr      = ext4_listxattr,
4200         .get_acl        = ext4_get_acl,
4201         .set_acl        = ext4_set_acl,
4202 };