fs/ext4/namei.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/ext4/namei.c
   4  *
   5  * Copyright (C) 1992, 1993, 1994, 1995
   6  * Remy Card ([email protected])
   7  * Laboratoire MASI - Institut Blaise Pascal
   8  * Universite Pierre et Marie Curie (Paris VI)
   9  *
  10  *  from
  11  *
  12  *  linux/fs/minix/namei.c
  13  *
  14  *  Copyright (C) 1991, 1992  Linus Torvalds
  15  *
  16  *  Big-endian to little-endian byte-swapping/bitmaps by
  17  *        David S. Miller ([email protected]), 1995
  18  *  Directory entry file type support and forward compatibility hooks
  19  *      for B-tree directories by Theodore Ts'o ([email protected]), 1998
  20  *  Hash Tree Directory indexing (c)
  21  *      Daniel Phillips, 2001
  22  *  Hash Tree Directory indexing porting
  23  *      Christopher Li, 2002
  24  *  Hash Tree Directory indexing cleanup
  25  *      Theodore Ts'o, 2002
  26  */
  27
  28 #include <linux/fs.h>
  29 #include <linux/pagemap.h>
  30 #include <linux/time.h>
  31 #include <linux/fcntl.h>
  32 #include <linux/stat.h>
  33 #include <linux/string.h>
  34 #include <linux/quotaops.h>
  35 #include <linux/buffer_head.h>
  36 #include <linux/bio.h>
  37 #include <linux/iversion.h>
  38 #include "ext4.h"
  39 #include "ext4_jbd2.h"
  40
  41 #include "xattr.h"
  42 #include "acl.h"
  43
  44 #include <trace/events/ext4.h>
  45 /*
  46  * define how far ahead to read directories while searching them.
  47  */
  48 #define NAMEI_RA_CHUNKS  2
  49 #define NAMEI_RA_BLOCKS  4
  50 #define NAMEI_RA_SIZE        (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS)
  51
  52 static struct buffer_head *ext4_append(handle_t *handle,
  53                                         struct inode *inode,
  54                                         ext4_lblk_t *block)
  55 {
  56         struct buffer_head *bh;
  57         int err;
  58
  59         if (unlikely(EXT4_SB(inode->i_sb)->s_max_dir_size_kb &&
  60                      ((inode->i_size >> 10) >=
  61                       EXT4_SB(inode->i_sb)->s_max_dir_size_kb)))
  62                 return ERR_PTR(-ENOSPC);
  63
  64         *block = inode->i_size >> inode->i_sb->s_blocksize_bits;
  65
  66         bh = ext4_bread(handle, inode, *block, EXT4_GET_BLOCKS_CREATE);
  67         if (IS_ERR(bh))
  68                 return bh;
  69         inode->i_size += inode->i_sb->s_blocksize;
  70         EXT4_I(inode)->i_disksize = inode->i_size;
  71         BUFFER_TRACE(bh, "get_write_access");
  72         err = ext4_journal_get_write_access(handle, bh);
  73         if (err) {
  74                 brelse(bh);
  75                 ext4_std_error(inode->i_sb, err);
  76                 return ERR_PTR(err);
  77         }
  78         return bh;
  79 }
  80
  81 static int ext4_dx_csum_verify(struct inode *inode,
  82                                struct ext4_dir_entry *dirent);
  83
  84 typedef enum {
  85         EITHER, INDEX, DIRENT
  86 } dirblock_type_t;
  87
  88 #define ext4_read_dirblock(inode, block, type) \
  89         __ext4_read_dirblock((inode), (block), (type), __func__, __LINE__)
  90
  91 static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
  92                                                 ext4_lblk_t block,
  93                                                 dirblock_type_t type,
  94                                                 const char *func,
  95                                                 unsigned int line)
  96 {
  97         struct buffer_head *bh;
  98         struct ext4_dir_entry *dirent;
  99         int is_dx_block = 0;
 100
 101         bh = ext4_bread(NULL, inode, block, 0);
 102         if (IS_ERR(bh)) {
 103                 __ext4_warning(inode->i_sb, func, line,
 104                                "inode #%lu: lblock %lu: comm %s: "
 105                                "error %ld reading directory block",
 106                                inode->i_ino, (unsigned long)block,
 107                                current->comm, PTR_ERR(bh));
 108
 109                 return bh;
 110         }
 111         if (!bh) {
 112                 ext4_error_inode(inode, func, line, block,
 113                                  "Directory hole found");
 114                 return ERR_PTR(-EFSCORRUPTED);
 115         }
 116         dirent = (struct ext4_dir_entry *) bh->b_data;
 117         /* Determine whether or not we have an index block */
 118         if (is_dx(inode)) {
 119                 if (block == 0)
 120                         is_dx_block = 1;
 121                 else if (ext4_rec_len_from_disk(dirent->rec_len,
 122                                                 inode->i_sb->s_blocksize) ==
 123                          inode->i_sb->s_blocksize)
 124                         is_dx_block = 1;
 125         }
 126         if (!is_dx_block && type == INDEX) {
 127                 ext4_error_inode(inode, func, line, block,
 128                        "directory leaf block found instead of index block");
 129                 return ERR_PTR(-EFSCORRUPTED);
 130         }
 131         if (!ext4_has_metadata_csum(inode->i_sb) ||
 132             buffer_verified(bh))
 133                 return bh;
 134
 135         /*
 136          * An empty leaf block can get mistaken for a index block; for
 137          * this reason, we can only check the index checksum when the
 138          * caller is sure it should be an index block.
 139          */
 140         if (is_dx_block && type == INDEX) {
 141                 if (ext4_dx_csum_verify(inode, dirent))
 142                         set_buffer_verified(bh);
 143                 else {
 144                         ext4_error_inode(inode, func, line, block,
 145                                          "Directory index failed checksum");
 146                         brelse(bh);
 147                         return ERR_PTR(-EFSBADCRC);
 148                 }
 149         }
 150         if (!is_dx_block) {
 151                 if (ext4_dirent_csum_verify(inode, dirent))
 152                         set_buffer_verified(bh);
 153                 else {
 154                         ext4_error_inode(inode, func, line, block,
 155                                          "Directory block failed checksum");
 156                         brelse(bh);
 157                         return ERR_PTR(-EFSBADCRC);
 158                 }
 159         }
 160         return bh;
 161 }
 162
 163 #ifndef assert
 164 #define assert(test) J_ASSERT(test)
 165 #endif
 166
 167 #ifdef DX_DEBUG
 168 #define dxtrace(command) command
 169 #else
 170 #define dxtrace(command)
 171 #endif
 172
 173 struct fake_dirent
 174 {
 175         __le32 inode;
 176         __le16 rec_len;
 177         u8 name_len;
 178         u8 file_type;
 179 };
 180
 181 struct dx_countlimit
 182 {
 183         __le16 limit;
 184         __le16 count;
 185 };
 186
 187 struct dx_entry
 188 {
 189         __le32 hash;
 190         __le32 block;
 191 };
 192
 193 /*
 194  * dx_root_info is laid out so that if it should somehow get overlaid by a
 195  * dirent the two low bits of the hash version will be zero.  Therefore, the
 196  * hash version mod 4 should never be 0.  Sincerely, the paranoia department.
 197  */
 198
 199 struct dx_root
 200 {
 201         struct fake_dirent dot;
 202         char dot_name[4];
 203         struct fake_dirent dotdot;
 204         char dotdot_name[4];
 205         struct dx_root_info
 206         {
 207                 __le32 reserved_zero;
 208                 u8 hash_version;
 209                 u8 info_length; /* 8 */
 210                 u8 indirect_levels;
 211                 u8 unused_flags;
 212         }
 213         info;
 214         struct dx_entry entries[0];
 215 };
 216
 217 struct dx_node
 218 {
 219         struct fake_dirent fake;
 220         struct dx_entry entries[0];
 221 };
 222
 223
 224 struct dx_frame
 225 {
 226         struct buffer_head *bh;
 227         struct dx_entry *entries;
 228         struct dx_entry *at;
 229 };
 230
 231 struct dx_map_entry
 232 {
 233         u32 hash;
 234         u16 offs;
 235         u16 size;
 236 };
 237
 238 /*
 239  * This goes at the end of each htree block.
 240  */
 241 struct dx_tail {
 242         u32 dt_reserved;
 243         __le32 dt_checksum;     /* crc32c(uuid+inum+dirblock) */
 244 };
 245
 246 static inline ext4_lblk_t dx_get_block(struct dx_entry *entry);
 247 static void dx_set_block(struct dx_entry *entry, ext4_lblk_t value);
 248 static inline unsigned dx_get_hash(struct dx_entry *entry);
 249 static void dx_set_hash(struct dx_entry *entry, unsigned value);
 250 static unsigned dx_get_count(struct dx_entry *entries);
 251 static unsigned dx_get_limit(struct dx_entry *entries);
 252 static void dx_set_count(struct dx_entry *entries, unsigned value);
 253 static void dx_set_limit(struct dx_entry *entries, unsigned value);
 254 static unsigned dx_root_limit(struct inode *dir, unsigned infosize);
 255 static unsigned dx_node_limit(struct inode *dir);
 256 static struct dx_frame *dx_probe(struct ext4_filename *fname,
 257                                  struct inode *dir,
 258                                  struct dx_hash_info *hinfo,
 259                                  struct dx_frame *frame);
 260 static void dx_release(struct dx_frame *frames);
 261 static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
 262                        unsigned blocksize, struct dx_hash_info *hinfo,
 263                        struct dx_map_entry map[]);
 264 static void dx_sort_map(struct dx_map_entry *map, unsigned count);
 265 static struct ext4_dir_entry_2 *dx_move_dirents(char *from, char *to,
 266                 struct dx_map_entry *offsets, int count, unsigned blocksize);
 267 static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize);
 268 static void dx_insert_block(struct dx_frame *frame,
 269                                         u32 hash, ext4_lblk_t block);
 270 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
 271                                  struct dx_frame *frame,
 272                                  struct dx_frame *frames,
 273                                  __u32 *start_hash);
 274 static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
 275                 struct ext4_filename *fname,
 276                 struct ext4_dir_entry_2 **res_dir);
 277 static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
 278                              struct inode *dir, struct inode *inode);
 279
 280 /* checksumming functions */
 281 void initialize_dirent_tail(struct ext4_dir_entry_tail *t,
 282                             unsigned int blocksize)
 283 {
 284         memset(t, 0, sizeof(struct ext4_dir_entry_tail));
 285         t->det_rec_len = ext4_rec_len_to_disk(
 286                         sizeof(struct ext4_dir_entry_tail), blocksize);
 287         t->det_reserved_ft = EXT4_FT_DIR_CSUM;
 288 }
 289
 290 /* Walk through a dirent block to find a checksum "dirent" at the tail */
 291 static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,
 292                                                    struct ext4_dir_entry *de)
 293 {
 294         struct ext4_dir_entry_tail *t;
 295
 296 #ifdef PARANOID
 297         struct ext4_dir_entry *d, *top;
 298
 299         d = de;
 300         top = (struct ext4_dir_entry *)(((void *)de) +
 301                 (EXT4_BLOCK_SIZE(inode->i_sb) -
 302                 sizeof(struct ext4_dir_entry_tail)));
 303         while (d < top && d->rec_len)
 304                 d = (struct ext4_dir_entry *)(((void *)d) +
 305                     le16_to_cpu(d->rec_len));
 306
 307         if (d != top)
 308                 return NULL;
 309
 310         t = (struct ext4_dir_entry_tail *)d;
 311 #else
 312         t = EXT4_DIRENT_TAIL(de, EXT4_BLOCK_SIZE(inode->i_sb));
 313 #endif
 314
 315         if (t->det_reserved_zero1 ||
 316             le16_to_cpu(t->det_rec_len) != sizeof(struct ext4_dir_entry_tail) ||
 317             t->det_reserved_zero2 ||
 318             t->det_reserved_ft != EXT4_FT_DIR_CSUM)
 319                 return NULL;
 320
 321         return t;
 322 }
 323
 324 static __le32 ext4_dirent_csum(struct inode *inode,
 325                                struct ext4_dir_entry *dirent, int size)
 326 {
 327         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 328         struct ext4_inode_info *ei = EXT4_I(inode);
 329         __u32 csum;
 330
 331         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
 332         return cpu_to_le32(csum);
 333 }
 334
 335 #define warn_no_space_for_csum(inode)                                   \
 336         __warn_no_space_for_csum((inode), __func__, __LINE__)
 337
 338 static void __warn_no_space_for_csum(struct inode *inode, const char *func,
 339                                      unsigned int line)
 340 {
 341         __ext4_warning_inode(inode, func, line,
 342                 "No space for directory leaf checksum. Please run e2fsck -D.");
 343 }
 344
 345 int ext4_dirent_csum_verify(struct inode *inode, struct ext4_dir_entry *dirent)
 346 {
 347         struct ext4_dir_entry_tail *t;
 348
 349         if (!ext4_has_metadata_csum(inode->i_sb))
 350                 return 1;
 351
 352         t = get_dirent_tail(inode, dirent);
 353         if (!t) {
 354                 warn_no_space_for_csum(inode);
 355                 return 0;
 356         }
 357
 358         if (t->det_checksum != ext4_dirent_csum(inode, dirent,
 359                                                 (void *)t - (void *)dirent))
 360                 return 0;
 361
 362         return 1;
 363 }
 364
 365 static void ext4_dirent_csum_set(struct inode *inode,
 366                                  struct ext4_dir_entry *dirent)
 367 {
 368         struct ext4_dir_entry_tail *t;
 369
 370         if (!ext4_has_metadata_csum(inode->i_sb))
 371                 return;
 372
 373         t = get_dirent_tail(inode, dirent);
 374         if (!t) {
 375                 warn_no_space_for_csum(inode);
 376                 return;
 377         }
 378
 379         t->det_checksum = ext4_dirent_csum(inode, dirent,
 380                                            (void *)t - (void *)dirent);
 381 }
 382
 383 int ext4_handle_dirty_dirent_node(handle_t *handle,
 384                                   struct inode *inode,
 385                                   struct buffer_head *bh)
 386 {
 387         ext4_dirent_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
 388         return ext4_handle_dirty_metadata(handle, inode, bh);
 389 }
 390
 391 static struct dx_countlimit *get_dx_countlimit(struct inode *inode,
 392                                                struct ext4_dir_entry *dirent,
 393                                                int *offset)
 394 {
 395         struct ext4_dir_entry *dp;
 396         struct dx_root_info *root;
 397         int count_offset;
 398
 399         if (le16_to_cpu(dirent->rec_len) == EXT4_BLOCK_SIZE(inode->i_sb))
 400                 count_offset = 8;
 401         else if (le16_to_cpu(dirent->rec_len) == 12) {
 402                 dp = (struct ext4_dir_entry *)(((void *)dirent) + 12);
 403                 if (le16_to_cpu(dp->rec_len) !=
 404                     EXT4_BLOCK_SIZE(inode->i_sb) - 12)
 405                         return NULL;
 406                 root = (struct dx_root_info *)(((void *)dp + 12));
 407                 if (root->reserved_zero ||
 408                     root->info_length != sizeof(struct dx_root_info))
 409                         return NULL;
 410                 count_offset = 32;
 411         } else
 412                 return NULL;
 413
 414         if (offset)
 415                 *offset = count_offset;
 416         return (struct dx_countlimit *)(((void *)dirent) + count_offset);
 417 }
 418
 419 static __le32 ext4_dx_csum(struct inode *inode, struct ext4_dir_entry *dirent,
 420                            int count_offset, int count, struct dx_tail *t)
 421 {
 422         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 423         struct ext4_inode_info *ei = EXT4_I(inode);
 424         __u32 csum;
 425         int size;
 426         __u32 dummy_csum = 0;
 427         int offset = offsetof(struct dx_tail, dt_checksum);
 428
 429         size = count_offset + (count * sizeof(struct dx_entry));
 430         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size);
 431         csum = ext4_chksum(sbi, csum, (__u8 *)t, offset);
 432         csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
 433
 434         return cpu_to_le32(csum);
 435 }
 436
 437 static int ext4_dx_csum_verify(struct inode *inode,
 438                                struct ext4_dir_entry *dirent)
 439 {
 440         struct dx_countlimit *c;
 441         struct dx_tail *t;
 442         int count_offset, limit, count;
 443
 444         if (!ext4_has_metadata_csum(inode->i_sb))
 445                 return 1;
 446
 447         c = get_dx_countlimit(inode, dirent, &count_offset);
 448         if (!c) {
 449                 EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
 450                 return 0;
 451         }
 452         limit = le16_to_cpu(c->limit);
 453         count = le16_to_cpu(c->count);
 454         if (count_offset + (limit * sizeof(struct dx_entry)) >
 455             EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
 456                 warn_no_space_for_csum(inode);
 457                 return 0;
 458         }
 459         t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
 460
 461         if (t->dt_checksum != ext4_dx_csum(inode, dirent, count_offset,
 462                                             count, t))
 463                 return 0;
 464         return 1;
 465 }
 466
 467 static void ext4_dx_csum_set(struct inode *inode, struct ext4_dir_entry *dirent)
 468 {
 469         struct dx_countlimit *c;
 470         struct dx_tail *t;
 471         int count_offset, limit, count;
 472
 473         if (!ext4_has_metadata_csum(inode->i_sb))
 474                 return;
 475
 476         c = get_dx_countlimit(inode, dirent, &count_offset);
 477         if (!c) {
 478                 EXT4_ERROR_INODE(inode, "dir seems corrupt?  Run e2fsck -D.");
 479                 return;
 480         }
 481         limit = le16_to_cpu(c->limit);
 482         count = le16_to_cpu(c->count);
 483         if (count_offset + (limit * sizeof(struct dx_entry)) >
 484             EXT4_BLOCK_SIZE(inode->i_sb) - sizeof(struct dx_tail)) {
 485                 warn_no_space_for_csum(inode);
 486                 return;
 487         }
 488         t = (struct dx_tail *)(((struct dx_entry *)c) + limit);
 489
 490         t->dt_checksum = ext4_dx_csum(inode, dirent, count_offset, count, t);
 491 }
 492
 493 static inline int ext4_handle_dirty_dx_node(handle_t *handle,
 494                                             struct inode *inode,
 495                                             struct buffer_head *bh)
 496 {
 497         ext4_dx_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
 498         return ext4_handle_dirty_metadata(handle, inode, bh);
 499 }
 500
 501 /*
 502  * p is at least 6 bytes before the end of page
 503  */
 504 static inline struct ext4_dir_entry_2 *
 505 ext4_next_entry(struct ext4_dir_entry_2 *p, unsigned long blocksize)
 506 {
 507         return (struct ext4_dir_entry_2 *)((char *)p +
 508                 ext4_rec_len_from_disk(p->rec_len, blocksize));
 509 }
 510
 511 /*
 512  * Future: use high four bits of block for coalesce-on-delete flags
 513  * Mask them off for now.
 514  */
 515
 516 static inline ext4_lblk_t dx_get_block(struct dx_entry *entry)
 517 {
 518         return le32_to_cpu(entry->block) & 0x0fffffff;
 519 }
 520
 521 static inline void dx_set_block(struct dx_entry *entry, ext4_lblk_t value)
 522 {
 523         entry->block = cpu_to_le32(value);
 524 }
 525
 526 static inline unsigned dx_get_hash(struct dx_entry *entry)
 527 {
 528         return le32_to_cpu(entry->hash);
 529 }
 530
 531 static inline void dx_set_hash(struct dx_entry *entry, unsigned value)
 532 {
 533         entry->hash = cpu_to_le32(value);
 534 }
 535
 536 static inline unsigned dx_get_count(struct dx_entry *entries)
 537 {
 538         return le16_to_cpu(((struct dx_countlimit *) entries)->count);
 539 }
 540
 541 static inline unsigned dx_get_limit(struct dx_entry *entries)
 542 {
 543         return le16_to_cpu(((struct dx_countlimit *) entries)->limit);
 544 }
 545
 546 static inline void dx_set_count(struct dx_entry *entries, unsigned value)
 547 {
 548         ((struct dx_countlimit *) entries)->count = cpu_to_le16(value);
 549 }
 550
 551 static inline void dx_set_limit(struct dx_entry *entries, unsigned value)
 552 {
 553         ((struct dx_countlimit *) entries)->limit = cpu_to_le16(value);
 554 }
 555
 556 static inline unsigned dx_root_limit(struct inode *dir, unsigned infosize)
 557 {
 558         unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(1) -
 559                 EXT4_DIR_REC_LEN(2) - infosize;
 560
 561         if (ext4_has_metadata_csum(dir->i_sb))
 562                 entry_space -= sizeof(struct dx_tail);
 563         return entry_space / sizeof(struct dx_entry);
 564 }
 565
 566 static inline unsigned dx_node_limit(struct inode *dir)
 567 {
 568         unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(0);
 569
 570         if (ext4_has_metadata_csum(dir->i_sb))
 571                 entry_space -= sizeof(struct dx_tail);
 572         return entry_space / sizeof(struct dx_entry);
 573 }
 574
 575 /*
 576  * Debug
 577  */
 578 #ifdef DX_DEBUG
 579 static void dx_show_index(char * label, struct dx_entry *entries)
 580 {
 581         int i, n = dx_get_count (entries);
 582         printk(KERN_DEBUG "%s index", label);
 583         for (i = 0; i < n; i++) {
 584                 printk(KERN_CONT " %x->%lu",
 585                        i ? dx_get_hash(entries + i) : 0,
 586                        (unsigned long)dx_get_block(entries + i));
 587         }
 588         printk(KERN_CONT "\n");
 589 }
 590
 591 struct stats
 592 {
 593         unsigned names;
 594         unsigned space;
 595         unsigned bcount;
 596 };
 597
 598 static struct stats dx_show_leaf(struct inode *dir,
 599                                 struct dx_hash_info *hinfo,
 600                                 struct ext4_dir_entry_2 *de,
 601                                 int size, int show_names)
 602 {
 603         unsigned names = 0, space = 0;
 604         char *base = (char *) de;
 605         struct dx_hash_info h = *hinfo;
 606
 607         printk("names: ");
 608         while ((char *) de < base + size)
 609         {
 610                 if (de->inode)
 611                 {
 612                         if (show_names)
 613                         {
 614 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 615                                 int len;
 616                                 char *name;
 617                                 struct fscrypt_str fname_crypto_str =
 618                                         FSTR_INIT(NULL, 0);
 619                                 int res = 0;
 620
 621                                 name  = de->name;
 622                                 len = de->name_len;
 623                                 if (ext4_encrypted_inode(dir))
 624                                         res = fscrypt_get_encryption_info(dir);
 625                                 if (res) {
 626                                         printk(KERN_WARNING "Error setting up"
 627                                                " fname crypto: %d\n", res);
 628                                 }
 629                                 if (!fscrypt_has_encryption_key(dir)) {
 630                                         /* Directory is not encrypted */
 631                                         ext4fs_dirhash(de->name,
 632                                                 de->name_len, &h);
 633                                         printk("%*.s:(U)%x.%u ", len,
 634                                                name, h.hash,
 635                                                (unsigned) ((char *) de
 636                                                            - base));
 637                                 } else {
 638                                         struct fscrypt_str de_name =
 639                                                 FSTR_INIT(name, len);
 640
 641                                         /* Directory is encrypted */
 642                                         res = fscrypt_fname_alloc_buffer(
 643                                                 dir, len,
 644                                                 &fname_crypto_str);
 645                                         if (res)
 646                                                 printk(KERN_WARNING "Error "
 647                                                         "allocating crypto "
 648                                                         "buffer--skipping "
 649                                                         "crypto\n");
 650                                         res = fscrypt_fname_disk_to_usr(dir,
 651                                                 0, 0, &de_name,
 652                                                 &fname_crypto_str);
 653                                         if (res) {
 654                                                 printk(KERN_WARNING "Error "
 655                                                         "converting filename "
 656                                                         "from disk to usr"
 657                                                         "\n");
 658                                                 name = "??";
 659                                                 len = 2;
 660                                         } else {
 661                                                 name = fname_crypto_str.name;
 662                                                 len = fname_crypto_str.len;
 663                                         }
 664                                         ext4fs_dirhash(de->name, de->name_len,
 665                                                        &h);
 666                                         printk("%*.s:(E)%x.%u ", len, name,
 667                                                h.hash, (unsigned) ((char *) de
 668                                                                    - base));
 669                                         fscrypt_fname_free_buffer(
 670                                                         &fname_crypto_str);
 671                                 }
 672 #else
 673                                 int len = de->name_len;
 674                                 char *name = de->name;
 675                                 ext4fs_dirhash(de->name, de->name_len, &h);
 676                                 printk("%*.s:%x.%u ", len, name, h.hash,
 677                                        (unsigned) ((char *) de - base));
 678 #endif
 679                         }
 680                         space += EXT4_DIR_REC_LEN(de->name_len);
 681                         names++;
 682                 }
 683                 de = ext4_next_entry(de, size);
 684         }
 685         printk(KERN_CONT "(%i)\n", names);
 686         return (struct stats) { names, space, 1 };
 687 }
 688
 689 struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir,
 690                              struct dx_entry *entries, int levels)
 691 {
 692         unsigned blocksize = dir->i_sb->s_blocksize;
 693         unsigned count = dx_get_count(entries), names = 0, space = 0, i;
 694         unsigned bcount = 0;
 695         struct buffer_head *bh;
 696         printk("%i indexed blocks...\n", count);
 697         for (i = 0; i < count; i++, entries++)
 698         {
 699                 ext4_lblk_t block = dx_get_block(entries);
 700                 ext4_lblk_t hash  = i ? dx_get_hash(entries): 0;
 701                 u32 range = i < count - 1? (dx_get_hash(entries + 1) - hash): ~hash;
 702                 struct stats stats;
 703                 printk("%s%3u:%03u hash %8x/%8x ",levels?"":"   ", i, block, hash, range);
 704                 bh = ext4_bread(NULL,dir, block, 0);
 705                 if (!bh || IS_ERR(bh))
 706                         continue;
 707                 stats = levels?
 708                    dx_show_entries(hinfo, dir, ((struct dx_node *) bh->b_data)->entries, levels - 1):
 709                    dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *)
 710                         bh->b_data, blocksize, 0);
 711                 names += stats.names;
 712                 space += stats.space;
 713                 bcount += stats.bcount;
 714                 brelse(bh);
 715         }
 716         if (bcount)
 717                 printk(KERN_DEBUG "%snames %u, fullness %u (%u%%)\n",
 718                        levels ? "" : "   ", names, space/bcount,
 719                        (space/bcount)*100/blocksize);
 720         return (struct stats) { names, space, bcount};
 721 }
 722 #endif /* DX_DEBUG */
 723
 724 /*
 725  * Probe for a directory leaf block to search.
 726  *
 727  * dx_probe can return ERR_BAD_DX_DIR, which means there was a format
 728  * error in the directory index, and the caller should fall back to
 729  * searching the directory normally.  The callers of dx_probe **MUST**
 730  * check for this error code, and make sure it never gets reflected
 731  * back to userspace.
 732  */
 733 static struct dx_frame *
 734 dx_probe(struct ext4_filename *fname, struct inode *dir,
 735          struct dx_hash_info *hinfo, struct dx_frame *frame_in)
 736 {
 737         unsigned count, indirect;
 738         struct dx_entry *at, *entries, *p, *q, *m;
 739         struct dx_root *root;
 740         struct dx_frame *frame = frame_in;
 741         struct dx_frame *ret_err = ERR_PTR(ERR_BAD_DX_DIR);
 742         u32 hash;
 743
 744         memset(frame_in, 0, EXT4_HTREE_LEVEL * sizeof(frame_in[0]));
 745         frame->bh = ext4_read_dirblock(dir, 0, INDEX);
 746         if (IS_ERR(frame->bh))
 747                 return (struct dx_frame *) frame->bh;
 748
 749         root = (struct dx_root *) frame->bh->b_data;
 750         if (root->info.hash_version != DX_HASH_TEA &&
 751             root->info.hash_version != DX_HASH_HALF_MD4 &&
 752             root->info.hash_version != DX_HASH_LEGACY) {
 753                 ext4_warning_inode(dir, "Unrecognised inode hash code %u",
 754                                    root->info.hash_version);
 755                 goto fail;
 756         }
 757         if (fname)
 758                 hinfo = &fname->hinfo;
 759         hinfo->hash_version = root->info.hash_version;
 760         if (hinfo->hash_version <= DX_HASH_TEA)
 761                 hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
 762         hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
 763         if (fname && fname_name(fname))
 764                 ext4fs_dirhash(fname_name(fname), fname_len(fname), hinfo);
 765         hash = hinfo->hash;
 766
 767         if (root->info.unused_flags & 1) {
 768                 ext4_warning_inode(dir, "Unimplemented hash flags: %#06x",
 769                                    root->info.unused_flags);
 770                 goto fail;
 771         }
 772
 773         indirect = root->info.indirect_levels;
 774         if (indirect >= ext4_dir_htree_level(dir->i_sb)) {
 775                 ext4_warning(dir->i_sb,
 776                              "Directory (ino: %lu) htree depth %#06x exceed"
 777                              "supported value", dir->i_ino,
 778                              ext4_dir_htree_level(dir->i_sb));
 779                 if (ext4_dir_htree_level(dir->i_sb) < EXT4_HTREE_LEVEL) {
 780                         ext4_warning(dir->i_sb, "Enable large directory "
 781                                                 "feature to access it");
 782                 }
 783                 goto fail;
 784         }
 785
 786         entries = (struct dx_entry *)(((char *)&root->info) +
 787                                       root->info.info_length);
 788
 789         if (dx_get_limit(entries) != dx_root_limit(dir,
 790                                                    root->info.info_length)) {
 791                 ext4_warning_inode(dir, "dx entry: limit %u != root limit %u",
 792                                    dx_get_limit(entries),
 793                                    dx_root_limit(dir, root->info.info_length));
 794                 goto fail;
 795         }
 796
 797         dxtrace(printk("Look up %x", hash));
 798         while (1) {
 799                 count = dx_get_count(entries);
 800                 if (!count || count > dx_get_limit(entries)) {
 801                         ext4_warning_inode(dir,
 802                                            "dx entry: count %u beyond limit %u",
 803                                            count, dx_get_limit(entries));
 804                         goto fail;
 805                 }
 806
 807                 p = entries + 1;
 808                 q = entries + count - 1;
 809                 while (p <= q) {
 810                         m = p + (q - p) / 2;
 811                         dxtrace(printk(KERN_CONT "."));
 812                         if (dx_get_hash(m) > hash)
 813                                 q = m - 1;
 814                         else
 815                                 p = m + 1;
 816                 }
 817
 818                 if (0) { // linear search cross check
 819                         unsigned n = count - 1;
 820                         at = entries;
 821                         while (n--)
 822                         {
 823                                 dxtrace(printk(KERN_CONT ","));
 824                                 if (dx_get_hash(++at) > hash)
 825                                 {
 826                                         at--;
 827                                         break;
 828                                 }
 829                         }
 830                         assert (at == p - 1);
 831                 }
 832
 833                 at = p - 1;
 834                 dxtrace(printk(KERN_CONT " %x->%u\n",
 835                                at == entries ? 0 : dx_get_hash(at),
 836                                dx_get_block(at)));
 837                 frame->entries = entries;
 838                 frame->at = at;
 839                 if (!indirect--)
 840                         return frame;
 841                 frame++;
 842                 frame->bh = ext4_read_dirblock(dir, dx_get_block(at), INDEX);
 843                 if (IS_ERR(frame->bh)) {
 844                         ret_err = (struct dx_frame *) frame->bh;
 845                         frame->bh = NULL;
 846                         goto fail;
 847                 }
 848                 entries = ((struct dx_node *) frame->bh->b_data)->entries;
 849
 850                 if (dx_get_limit(entries) != dx_node_limit(dir)) {
 851                         ext4_warning_inode(dir,
 852                                 "dx entry: limit %u != node limit %u",
 853                                 dx_get_limit(entries), dx_node_limit(dir));
 854                         goto fail;
 855                 }
 856         }
 857 fail:
 858         while (frame >= frame_in) {
 859                 brelse(frame->bh);
 860                 frame--;
 861         }
 862
 863         if (ret_err == ERR_PTR(ERR_BAD_DX_DIR))
 864                 ext4_warning_inode(dir,
 865                         "Corrupt directory, running e2fsck is recommended");
 866         return ret_err;
 867 }
 868
 869 static void dx_release(struct dx_frame *frames)
 870 {
 871         struct dx_root_info *info;
 872         int i;
 873
 874         if (frames[0].bh == NULL)
 875                 return;
 876
 877         info = &((struct dx_root *)frames[0].bh->b_data)->info;
 878         for (i = 0; i <= info->indirect_levels; i++) {
 879                 if (frames[i].bh == NULL)
 880                         break;
 881                 brelse(frames[i].bh);
 882                 frames[i].bh = NULL;
 883         }
 884 }
 885
 886 /*
 887  * This function increments the frame pointer to search the next leaf
 888  * block, and reads in the necessary intervening nodes if the search
 889  * should be necessary.  Whether or not the search is necessary is
 890  * controlled by the hash parameter.  If the hash value is even, then
 891  * the search is only continued if the next block starts with that
 892  * hash value.  This is used if we are searching for a specific file.
 893  *
 894  * If the hash value is HASH_NB_ALWAYS, then always go to the next block.
 895  *
 896  * This function returns 1 if the caller should continue to search,
 897  * or 0 if it should not.  If there is an error reading one of the
 898  * index blocks, it will a negative error code.
 899  *
 900  * If start_hash is non-null, it will be filled in with the starting
 901  * hash of the next page.
 902  */
 903 static int ext4_htree_next_block(struct inode *dir, __u32 hash,
 904                                  struct dx_frame *frame,
 905                                  struct dx_frame *frames,
 906                                  __u32 *start_hash)
 907 {
 908         struct dx_frame *p;
 909         struct buffer_head *bh;
 910         int num_frames = 0;
 911         __u32 bhash;
 912
 913         p = frame;
 914         /*
 915          * Find the next leaf page by incrementing the frame pointer.
 916          * If we run out of entries in the interior node, loop around and
 917          * increment pointer in the parent node.  When we break out of
 918          * this loop, num_frames indicates the number of interior
 919          * nodes need to be read.
 920          */
 921         while (1) {
 922                 if (++(p->at) < p->entries + dx_get_count(p->entries))
 923                         break;
 924                 if (p == frames)
 925                         return 0;
 926                 num_frames++;
 927                 p--;
 928         }
 929
 930         /*
 931          * If the hash is 1, then continue only if the next page has a
 932          * continuation hash of any value.  This is used for readdir
 933          * handling.  Otherwise, check to see if the hash matches the
 934          * desired contiuation hash.  If it doesn't, return since
 935          * there's no point to read in the successive index pages.
 936          */
 937         bhash = dx_get_hash(p->at);
 938         if (start_hash)
 939                 *start_hash = bhash;
 940         if ((hash & 1) == 0) {
 941                 if ((bhash & ~1) != hash)
 942                         return 0;
 943         }
 944         /*
 945          * If the hash is HASH_NB_ALWAYS, we always go to the next
 946          * block so no check is necessary
 947          */
 948         while (num_frames--) {
 949                 bh = ext4_read_dirblock(dir, dx_get_block(p->at), INDEX);
 950                 if (IS_ERR(bh))
 951                         return PTR_ERR(bh);
 952                 p++;
 953                 brelse(p->bh);
 954                 p->bh = bh;
 955                 p->at = p->entries = ((struct dx_node *) bh->b_data)->entries;
 956         }
 957         return 1;
 958 }
 959
 960
 961 /*
 962  * This function fills a red-black tree with information from a
 963  * directory block.  It returns the number directory entries loaded
 964  * into the tree.  If there is an error it is returned in err.
 965  */
 966 static int htree_dirblock_to_tree(struct file *dir_file,
 967                                   struct inode *dir, ext4_lblk_t block,
 968                                   struct dx_hash_info *hinfo,
 969                                   __u32 start_hash, __u32 start_minor_hash)
 970 {
 971         struct buffer_head *bh;
 972         struct ext4_dir_entry_2 *de, *top;
 973         int err = 0, count = 0;
 974         struct fscrypt_str fname_crypto_str = FSTR_INIT(NULL, 0), tmp_str;
 975
 976         dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
 977                                                         (unsigned long)block));
 978         bh = ext4_read_dirblock(dir, block, DIRENT);
 979         if (IS_ERR(bh))
 980                 return PTR_ERR(bh);
 981
 982         de = (struct ext4_dir_entry_2 *) bh->b_data;
 983         top = (struct ext4_dir_entry_2 *) ((char *) de +
 984                                            dir->i_sb->s_blocksize -
 985                                            EXT4_DIR_REC_LEN(0));
 986 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 987         /* Check if the directory is encrypted */
 988         if (ext4_encrypted_inode(dir)) {
 989                 err = fscrypt_get_encryption_info(dir);
 990                 if (err < 0) {
 991                         brelse(bh);
 992                         return err;
 993                 }
 994                 err = fscrypt_fname_alloc_buffer(dir, EXT4_NAME_LEN,
 995                                                      &fname_crypto_str);
 996                 if (err < 0) {
 997                         brelse(bh);
 998                         return err;
 999                 }
1000         }
1001 #endif
1002         for (; de < top; de = ext4_next_entry(de, dir->i_sb->s_blocksize)) {
1003                 if (ext4_check_dir_entry(dir, NULL, de, bh,
1004                                 bh->b_data, bh->b_size,
1005                                 (block<<EXT4_BLOCK_SIZE_BITS(dir->i_sb))
1006                                          + ((char *)de - bh->b_data))) {
1007                         /* silently ignore the rest of the block */
1008                         break;
1009                 }
1010                 ext4fs_dirhash(de->name, de->name_len, hinfo);
1011                 if ((hinfo->hash < start_hash) ||
1012                     ((hinfo->hash == start_hash) &&
1013                      (hinfo->minor_hash < start_minor_hash)))
1014                         continue;
1015                 if (de->inode == 0)
1016                         continue;
1017                 if (!ext4_encrypted_inode(dir)) {
1018                         tmp_str.name = de->name;
1019                         tmp_str.len = de->name_len;
1020                         err = ext4_htree_store_dirent(dir_file,
1021                                    hinfo->hash, hinfo->minor_hash, de,
1022                                    &tmp_str);
1023                 } else {
1024                         int save_len = fname_crypto_str.len;
1025                         struct fscrypt_str de_name = FSTR_INIT(de->name,
1026                                                                 de->name_len);
1027
1028                         /* Directory is encrypted */
1029                         err = fscrypt_fname_disk_to_usr(dir, hinfo->hash,
1030                                         hinfo->minor_hash, &de_name,
1031                                         &fname_crypto_str);
1032                         if (err) {
1033                                 count = err;
1034                                 goto errout;
1035                         }
1036                         err = ext4_htree_store_dirent(dir_file,
1037                                    hinfo->hash, hinfo->minor_hash, de,
1038                                         &fname_crypto_str);
1039                         fname_crypto_str.len = save_len;
1040                 }
1041                 if (err != 0) {
1042                         count = err;
1043                         goto errout;
1044                 }
1045                 count++;
1046         }
1047 errout:
1048         brelse(bh);
1049 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1050         fscrypt_fname_free_buffer(&fname_crypto_str);
1051 #endif
1052         return count;
1053 }
1054
1055
1056 /*
1057  * This function fills a red-black tree with information from a
1058  * directory.  We start scanning the directory in hash order, starting
1059  * at start_hash and start_minor_hash.
1060  *
1061  * This function returns the number of entries inserted into the tree,
1062  * or a negative error code.
1063  */
1064 int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
1065                          __u32 start_minor_hash, __u32 *next_hash)
1066 {
1067         struct dx_hash_info hinfo;
1068         struct ext4_dir_entry_2 *de;
1069         struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
1070         struct inode *dir;
1071         ext4_lblk_t block;
1072         int count = 0;
1073         int ret, err;
1074         __u32 hashval;
1075         struct fscrypt_str tmp_str;
1076
1077         dxtrace(printk(KERN_DEBUG "In htree_fill_tree, start hash: %x:%x\n",
1078                        start_hash, start_minor_hash));
1079         dir = file_inode(dir_file);
1080         if (!(ext4_test_inode_flag(dir, EXT4_INODE_INDEX))) {
1081                 hinfo.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
1082                 if (hinfo.hash_version <= DX_HASH_TEA)
1083                         hinfo.hash_version +=
1084                                 EXT4_SB(dir->i_sb)->s_hash_unsigned;
1085                 hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
1086                 if (ext4_has_inline_data(dir)) {
1087                         int has_inline_data = 1;
1088                         count = htree_inlinedir_to_tree(dir_file, dir, 0,
1089                                                         &hinfo, start_hash,
1090                                                         start_minor_hash,
1091                                                         &has_inline_data);
1092                         if (has_inline_data) {
1093                                 *next_hash = ~0;
1094                                 return count;
1095                         }
1096                 }
1097                 count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
1098                                                start_hash, start_minor_hash);
1099                 *next_hash = ~0;
1100                 return count;
1101         }
1102         hinfo.hash = start_hash;
1103         hinfo.minor_hash = 0;
1104         frame = dx_probe(NULL, dir, &hinfo, frames);
1105         if (IS_ERR(frame))
1106                 return PTR_ERR(frame);
1107
1108         /* Add '.' and '..' from the htree header */
1109         if (!start_hash && !start_minor_hash) {
1110                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
1111                 tmp_str.name = de->name;
1112                 tmp_str.len = de->name_len;
1113                 err = ext4_htree_store_dirent(dir_file, 0, 0,
1114                                               de, &tmp_str);
1115                 if (err != 0)
1116                         goto errout;
1117                 count++;
1118         }
1119         if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) {
1120                 de = (struct ext4_dir_entry_2 *) frames[0].bh->b_data;
1121                 de = ext4_next_entry(de, dir->i_sb->s_blocksize);
1122                 tmp_str.name = de->name;
1123                 tmp_str.len = de->name_len;
1124                 err = ext4_htree_store_dirent(dir_file, 2, 0,
1125                                               de, &tmp_str);
1126                 if (err != 0)
1127                         goto errout;
1128                 count++;
1129         }
1130
1131         while (1) {
1132                 if (fatal_signal_pending(current)) {
1133                         err = -ERESTARTSYS;
1134                         goto errout;
1135                 }
1136                 cond_resched();
1137                 block = dx_get_block(frame->at);
1138                 ret = htree_dirblock_to_tree(dir_file, dir, block, &hinfo,
1139                                              start_hash, start_minor_hash);
1140                 if (ret < 0) {
1141                         err = ret;
1142                         goto errout;
1143                 }
1144                 count += ret;
1145                 hashval = ~0;
1146                 ret = ext4_htree_next_block(dir, HASH_NB_ALWAYS,
1147                                             frame, frames, &hashval);
1148                 *next_hash = hashval;
1149                 if (ret < 0) {
1150                         err = ret;
1151                         goto errout;
1152                 }
1153                 /*
1154                  * Stop if:  (a) there are no more entries, or
1155                  * (b) we have inserted at least one entry and the
1156                  * next hash value is not a continuation
1157                  */
1158                 if ((ret == 0) ||
1159                     (count && ((hashval & 1) == 0)))
1160                         break;
1161         }
1162         dx_release(frames);
1163         dxtrace(printk(KERN_DEBUG "Fill tree: returned %d entries, "
1164                        "next hash: %x\n", count, *next_hash));
1165         return count;
1166 errout:
1167         dx_release(frames);
1168         return (err);
1169 }
1170
1171 static inline int search_dirblock(struct buffer_head *bh,
1172                                   struct inode *dir,
1173                                   struct ext4_filename *fname,
1174                                   unsigned int offset,
1175                                   struct ext4_dir_entry_2 **res_dir)
1176 {
1177         return ext4_search_dir(bh, bh->b_data, dir->i_sb->s_blocksize, dir,
1178                                fname, offset, res_dir);
1179 }
1180
1181 /*
1182  * Directory block splitting, compacting
1183  */
1184
1185 /*
1186  * Create map of hash values, offsets, and sizes, stored at end of block.
1187  * Returns number of entries mapped.
1188  */
1189 static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
1190                        unsigned blocksize, struct dx_hash_info *hinfo,
1191                        struct dx_map_entry *map_tail)
1192 {
1193         int count = 0;
1194         char *base = (char *) de;
1195         struct dx_hash_info h = *hinfo;
1196
1197         while ((char *) de < base + blocksize) {
1198                 if (de->name_len && de->inode) {
1199                         ext4fs_dirhash(de->name, de->name_len, &h);
1200                         map_tail--;
1201                         map_tail->hash = h.hash;
1202                         map_tail->offs = ((char *) de - base)>>2;
1203                         map_tail->size = le16_to_cpu(de->rec_len);
1204                         count++;
1205                         cond_resched();
1206                 }
1207                 /* XXX: do we need to check rec_len == 0 case? -Chris */
1208                 de = ext4_next_entry(de, blocksize);
1209         }
1210         return count;
1211 }
1212
1213 /* Sort map by hash value */
1214 static void dx_sort_map (struct dx_map_entry *map, unsigned count)
1215 {
1216         struct dx_map_entry *p, *q, *top = map + count - 1;
1217         int more;
1218         /* Combsort until bubble sort doesn't suck */
1219         while (count > 2) {
1220                 count = count*10/13;
1221                 if (count - 9 < 2) /* 9, 10 -> 11 */
1222                         count = 11;
1223                 for (p = top, q = p - count; q >= map; p--, q--)
1224                         if (p->hash < q->hash)
1225                                 swap(*p, *q);
1226         }
1227         /* Garden variety bubble sort */
1228         do {
1229                 more = 0;
1230                 q = top;
1231                 while (q-- > map) {
1232                         if (q[1].hash >= q[0].hash)
1233                                 continue;
1234                         swap(*(q+1), *q);
1235                         more = 1;
1236                 }
1237         } while(more);
1238 }
1239
1240 static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
1241 {
1242         struct dx_entry *entries = frame->entries;
1243         struct dx_entry *old = frame->at, *new = old + 1;
1244         int count = dx_get_count(entries);
1245
1246         assert(count < dx_get_limit(entries));
1247         assert(old < entries + count);
1248         memmove(new + 1, new, (char *)(entries + count) - (char *)(new));
1249         dx_set_hash(new, hash);
1250         dx_set_block(new, block);
1251         dx_set_count(entries, count + 1);
1252 }
1253
1254 /*
1255  * Test whether a directory entry matches the filename being searched for.
1256  *
1257  * Return: %true if the directory entry matches, otherwise %false.
1258  */
1259 static inline bool ext4_match(const struct ext4_filename *fname,
1260                               const struct ext4_dir_entry_2 *de)
1261 {
1262         struct fscrypt_name f;
1263
1264         if (!de->inode)
1265                 return false;
1266
1267         f.usr_fname = fname->usr_fname;
1268         f.disk_name = fname->disk_name;
1269 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1270         f.crypto_buf = fname->crypto_buf;
1271 #endif
1272         return fscrypt_match_name(&f, de->name, de->name_len);
1273 }
1274
1275 /*
1276  * Returns 0 if not found, -1 on failure, and 1 on success
1277  */
1278 int ext4_search_dir(struct buffer_head *bh, char *search_buf, int buf_size,
1279                     struct inode *dir, struct ext4_filename *fname,
1280                     unsigned int offset, struct ext4_dir_entry_2 **res_dir)
1281 {
1282         struct ext4_dir_entry_2 * de;
1283         char * dlimit;
1284         int de_len;
1285
1286         de = (struct ext4_dir_entry_2 *)search_buf;
1287         dlimit = search_buf + buf_size;
1288         while ((char *) de < dlimit) {
1289                 /* this code is executed quadratically often */
1290                 /* do minimal checking `by hand' */
1291                 if ((char *) de + de->name_len <= dlimit &&
1292                     ext4_match(fname, de)) {
1293                         /* found a match - just to be sure, do
1294                          * a full check */
1295                         if (ext4_check_dir_entry(dir, NULL, de, bh, bh->b_data,
1296                                                  bh->b_size, offset))
1297                                 return -1;
1298                         *res_dir = de;
1299                         return 1;
1300                 }
1301                 /* prevent looping on a bad block */
1302                 de_len = ext4_rec_len_from_disk(de->rec_len,
1303                                                 dir->i_sb->s_blocksize);
1304                 if (de_len <= 0)
1305                         return -1;
1306                 offset += de_len;
1307                 de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
1308         }
1309         return 0;
1310 }
1311
1312 static int is_dx_internal_node(struct inode *dir, ext4_lblk_t block,
1313                                struct ext4_dir_entry *de)
1314 {
1315         struct super_block *sb = dir->i_sb;
1316
1317         if (!is_dx(dir))
1318                 return 0;
1319         if (block == 0)
1320                 return 1;
1321         if (de->inode == 0 &&
1322             ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) ==
1323                         sb->s_blocksize)
1324                 return 1;
1325         return 0;
1326 }
1327
1328 /*
1329  *      ext4_find_entry()
1330  *
1331  * finds an entry in the specified directory with the wanted name. It
1332  * returns the cache buffer in which the entry was found, and the entry
1333  * itself (as a parameter - res_dir). It does NOT read the inode of the
1334  * entry - you'll have to do that yourself if you want to.
1335  *
1336  * The returned buffer_head has ->b_count elevated.  The caller is expected
1337  * to brelse() it when appropriate.
1338  */
1339 static struct buffer_head * ext4_find_entry (struct inode *dir,
1340                                         const struct qstr *d_name,
1341                                         struct ext4_dir_entry_2 **res_dir,
1342                                         int *inlined)
1343 {
1344         struct super_block *sb;
1345         struct buffer_head *bh_use[NAMEI_RA_SIZE];
1346         struct buffer_head *bh, *ret = NULL;
1347         ext4_lblk_t start, block;
1348         const u8 *name = d_name->name;
1349         size_t ra_max = 0;      /* Number of bh's in the readahead
1350                                    buffer, bh_use[] */
1351         size_t ra_ptr = 0;      /* Current index into readahead
1352                                    buffer */
1353         ext4_lblk_t  nblocks;
1354         int i, namelen, retval;
1355         struct ext4_filename fname;
1356
1357         *res_dir = NULL;
1358         sb = dir->i_sb;
1359         namelen = d_name->len;
1360         if (namelen > EXT4_NAME_LEN)
1361                 return NULL;
1362
1363         retval = ext4_fname_setup_filename(dir, d_name, 1, &fname);
1364         if (retval == -ENOENT)
1365                 return NULL;
1366         if (retval)
1367                 return ERR_PTR(retval);
1368
1369         if (ext4_has_inline_data(dir)) {
1370                 int has_inline_data = 1;
1371                 ret = ext4_find_inline_entry(dir, &fname, res_dir,
1372                                              &has_inline_data);
1373                 if (has_inline_data) {
1374                         if (inlined)
1375                                 *inlined = 1;
1376                         goto cleanup_and_exit;
1377                 }
1378         }
1379
1380         if ((namelen <= 2) && (name[0] == '.') &&
1381             (name[1] == '.' || name[1] == '\0')) {
1382                 /*
1383                  * "." or ".." will only be in the first block
1384                  * NFS may look up ".."; "." should be handled by the VFS
1385                  */
1386                 block = start = 0;
1387                 nblocks = 1;
1388                 goto restart;
1389         }
1390         if (is_dx(dir)) {
1391                 ret = ext4_dx_find_entry(dir, &fname, res_dir);
1392                 /*
1393                  * On success, or if the error was file not found,
1394                  * return.  Otherwise, fall back to doing a search the
1395                  * old fashioned way.
1396                  */
1397                 if (!IS_ERR(ret) || PTR_ERR(ret) != ERR_BAD_DX_DIR)
1398                         goto cleanup_and_exit;
1399                 dxtrace(printk(KERN_DEBUG "ext4_find_entry: dx failed, "
1400                                "falling back\n"));
1401                 ret = NULL;
1402         }
1403         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1404         if (!nblocks) {
1405                 ret = NULL;
1406                 goto cleanup_and_exit;
1407         }
1408         start = EXT4_I(dir)->i_dir_start_lookup;
1409         if (start >= nblocks)
1410                 start = 0;
1411         block = start;
1412 restart:
1413         do {
1414                 /*
1415                  * We deal with the read-ahead logic here.
1416                  */
1417                 if (ra_ptr >= ra_max) {
1418                         /* Refill the readahead buffer */
1419                         ra_ptr = 0;
1420                         if (block < start)
1421                                 ra_max = start - block;
1422                         else
1423                                 ra_max = nblocks - block;
1424                         ra_max = min(ra_max, ARRAY_SIZE(bh_use));
1425                         retval = ext4_bread_batch(dir, block, ra_max,
1426                                                   false /* wait */, bh_use);
1427                         if (retval) {
1428                                 ret = ERR_PTR(retval);
1429                                 ra_max = 0;
1430                                 goto cleanup_and_exit;
1431                         }
1432                 }
1433                 if ((bh = bh_use[ra_ptr++]) == NULL)
1434                         goto next;
1435                 wait_on_buffer(bh);
1436                 if (!buffer_uptodate(bh)) {
1437                         EXT4_ERROR_INODE(dir, "reading directory lblock %lu",
1438                                          (unsigned long) block);
1439                         brelse(bh);
1440                         ret = ERR_PTR(-EIO);
1441                         goto cleanup_and_exit;
1442                 }
1443                 if (!buffer_verified(bh) &&
1444                     !is_dx_internal_node(dir, block,
1445                                          (struct ext4_dir_entry *)bh->b_data) &&
1446                     !ext4_dirent_csum_verify(dir,
1447                                 (struct ext4_dir_entry *)bh->b_data)) {
1448                         EXT4_ERROR_INODE(dir, "checksumming directory "
1449                                          "block %lu", (unsigned long)block);
1450                         brelse(bh);
1451                         ret = ERR_PTR(-EFSBADCRC);
1452                         goto cleanup_and_exit;
1453                 }
1454                 set_buffer_verified(bh);
1455                 i = search_dirblock(bh, dir, &fname,
1456                             block << EXT4_BLOCK_SIZE_BITS(sb), res_dir);
1457                 if (i == 1) {
1458                         EXT4_I(dir)->i_dir_start_lookup = block;
1459                         ret = bh;
1460                         goto cleanup_and_exit;
1461                 } else {
1462                         brelse(bh);
1463                         if (i < 0)
1464                                 goto cleanup_and_exit;
1465                 }
1466         next:
1467                 if (++block >= nblocks)
1468                         block = 0;
1469         } while (block != start);
1470
1471         /*
1472          * If the directory has grown while we were searching, then
1473          * search the last part of the directory before giving up.
1474          */
1475         block = nblocks;
1476         nblocks = dir->i_size >> EXT4_BLOCK_SIZE_BITS(sb);
1477         if (block < nblocks) {
1478                 start = 0;
1479                 goto restart;
1480         }
1481
1482 cleanup_and_exit:
1483         /* Clean up the read-ahead blocks */
1484         for (; ra_ptr < ra_max; ra_ptr++)
1485                 brelse(bh_use[ra_ptr]);
1486         ext4_fname_free_filename(&fname);
1487         return ret;
1488 }
1489
1490 static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
1491                         struct ext4_filename *fname,
1492                         struct ext4_dir_entry_2 **res_dir)
1493 {
1494         struct super_block * sb = dir->i_sb;
1495         struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
1496         struct buffer_head *bh;
1497         ext4_lblk_t block;
1498         int retval;
1499
1500 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1501         *res_dir = NULL;
1502 #endif
1503         frame = dx_probe(fname, dir, NULL, frames);
1504         if (IS_ERR(frame))
1505                 return (struct buffer_head *) frame;
1506         do {
1507                 block = dx_get_block(frame->at);
1508                 bh = ext4_read_dirblock(dir, block, DIRENT);
1509                 if (IS_ERR(bh))
1510                         goto errout;
1511
1512                 retval = search_dirblock(bh, dir, fname,
1513                                          block << EXT4_BLOCK_SIZE_BITS(sb),
1514                                          res_dir);
1515                 if (retval == 1)
1516                         goto success;
1517                 brelse(bh);
1518                 if (retval == -1) {
1519                         bh = ERR_PTR(ERR_BAD_DX_DIR);
1520                         goto errout;
1521                 }
1522
1523                 /* Check to see if we should continue to search */
1524                 retval = ext4_htree_next_block(dir, fname->hinfo.hash, frame,
1525                                                frames, NULL);
1526                 if (retval < 0) {
1527                         ext4_warning_inode(dir,
1528                                 "error %d reading directory index block",
1529                                 retval);
1530                         bh = ERR_PTR(retval);
1531                         goto errout;
1532                 }
1533         } while (retval == 1);
1534
1535         bh = NULL;
1536 errout:
1537         dxtrace(printk(KERN_DEBUG "%s not found\n", fname->usr_fname->name));
1538 success:
1539         dx_release(frames);
1540         return bh;
1541 }
1542
1543 static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
1544 {
1545         struct inode *inode;
1546         struct ext4_dir_entry_2 *de;
1547         struct buffer_head *bh;
1548         int err;
1549
1550         err = fscrypt_prepare_lookup(dir, dentry, flags);
1551         if (err)
1552                 return ERR_PTR(err);
1553
1554         if (dentry->d_name.len > EXT4_NAME_LEN)
1555                 return ERR_PTR(-ENAMETOOLONG);
1556
1557         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
1558         if (IS_ERR(bh))
1559                 return (struct dentry *) bh;
1560         inode = NULL;
1561         if (bh) {
1562                 __u32 ino = le32_to_cpu(de->inode);
1563                 brelse(bh);
1564                 if (!ext4_valid_inum(dir->i_sb, ino)) {
1565                         EXT4_ERROR_INODE(dir, "bad inode number: %u", ino);
1566                         return ERR_PTR(-EFSCORRUPTED);
1567                 }
1568                 if (unlikely(ino == dir->i_ino)) {
1569                         EXT4_ERROR_INODE(dir, "'%pd' linked to parent dir",
1570                                          dentry);
1571                         return ERR_PTR(-EFSCORRUPTED);
1572                 }
1573                 inode = ext4_iget_normal(dir->i_sb, ino);
1574                 if (inode == ERR_PTR(-ESTALE)) {
1575                         EXT4_ERROR_INODE(dir,
1576                                          "deleted inode referenced: %u",
1577                                          ino);
1578                         return ERR_PTR(-EFSCORRUPTED);
1579                 }
1580                 if (!IS_ERR(inode) && ext4_encrypted_inode(dir) &&
1581                     (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) &&
1582                     !fscrypt_has_permitted_context(dir, inode)) {
1583                         ext4_warning(inode->i_sb,
1584                                      "Inconsistent encryption contexts: %lu/%lu",
1585                                      dir->i_ino, inode->i_ino);
1586                         iput(inode);
1587                         return ERR_PTR(-EPERM);
1588                 }
1589         }
1590         return d_splice_alias(inode, dentry);
1591 }
1592
1593
1594 struct dentry *ext4_get_parent(struct dentry *child)
1595 {
1596         __u32 ino;
1597         static const struct qstr dotdot = QSTR_INIT("..", 2);
1598         struct ext4_dir_entry_2 * de;
1599         struct buffer_head *bh;
1600
1601         bh = ext4_find_entry(d_inode(child), &dotdot, &de, NULL);
1602         if (IS_ERR(bh))
1603                 return (struct dentry *) bh;
1604         if (!bh)
1605                 return ERR_PTR(-ENOENT);
1606         ino = le32_to_cpu(de->inode);
1607         brelse(bh);
1608
1609         if (!ext4_valid_inum(child->d_sb, ino)) {
1610                 EXT4_ERROR_INODE(d_inode(child),
1611                                  "bad parent inode number: %u", ino);
1612                 return ERR_PTR(-EFSCORRUPTED);
1613         }
1614
1615         return d_obtain_alias(ext4_iget_normal(child->d_sb, ino));
1616 }
1617
1618 /*
1619  * Move count entries from end of map between two memory locations.
1620  * Returns pointer to last entry moved.
1621  */
1622 static struct ext4_dir_entry_2 *
1623 dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count,
1624                 unsigned blocksize)
1625 {
1626         unsigned rec_len = 0;
1627
1628         while (count--) {
1629                 struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)
1630                                                 (from + (map->offs<<2));
1631                 rec_len = EXT4_DIR_REC_LEN(de->name_len);
1632                 memcpy (to, de, rec_len);
1633                 ((struct ext4_dir_entry_2 *) to)->rec_len =
1634                                 ext4_rec_len_to_disk(rec_len, blocksize);
1635                 de->inode = 0;
1636                 map++;
1637                 to += rec_len;
1638         }
1639         return (struct ext4_dir_entry_2 *) (to - rec_len);
1640 }
1641
1642 /*
1643  * Compact each dir entry in the range to the minimal rec_len.
1644  * Returns pointer to last entry in range.
1645  */
1646 static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize)
1647 {
1648         struct ext4_dir_entry_2 *next, *to, *prev, *de = (struct ext4_dir_entry_2 *) base;
1649         unsigned rec_len = 0;
1650
1651         prev = to = de;
1652         while ((char*)de < base + blocksize) {
1653                 next = ext4_next_entry(de, blocksize);
1654                 if (de->inode && de->name_len) {
1655                         rec_len = EXT4_DIR_REC_LEN(de->name_len);
1656                         if (de > to)
1657                                 memmove(to, de, rec_len);
1658                         to->rec_len = ext4_rec_len_to_disk(rec_len, blocksize);
1659                         prev = to;
1660                         to = (struct ext4_dir_entry_2 *) (((char *) to) + rec_len);
1661                 }
1662                 de = next;
1663         }
1664         return prev;
1665 }
1666
1667 /*
1668  * Split a full leaf block to make room for a new dir entry.
1669  * Allocate a new block, and move entries so that they are approx. equally full.
1670  * Returns pointer to de in block into which the new entry will be inserted.
1671  */
1672 static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
1673                         struct buffer_head **bh,struct dx_frame *frame,
1674                         struct dx_hash_info *hinfo)
1675 {
1676         unsigned blocksize = dir->i_sb->s_blocksize;
1677         unsigned count, continued;
1678         struct buffer_head *bh2;
1679         ext4_lblk_t newblock;
1680         u32 hash2;
1681         struct dx_map_entry *map;
1682         char *data1 = (*bh)->b_data, *data2;
1683         unsigned split, move, size;
1684         struct ext4_dir_entry_2 *de = NULL, *de2;
1685         struct ext4_dir_entry_tail *t;
1686         int     csum_size = 0;
1687         int     err = 0, i;
1688
1689         if (ext4_has_metadata_csum(dir->i_sb))
1690                 csum_size = sizeof(struct ext4_dir_entry_tail);
1691
1692         bh2 = ext4_append(handle, dir, &newblock);
1693         if (IS_ERR(bh2)) {
1694                 brelse(*bh);
1695                 *bh = NULL;
1696                 return (struct ext4_dir_entry_2 *) bh2;
1697         }
1698
1699         BUFFER_TRACE(*bh, "get_write_access");
1700         err = ext4_journal_get_write_access(handle, *bh);
1701         if (err)
1702                 goto journal_error;
1703
1704         BUFFER_TRACE(frame->bh, "get_write_access");
1705         err = ext4_journal_get_write_access(handle, frame->bh);
1706         if (err)
1707                 goto journal_error;
1708
1709         data2 = bh2->b_data;
1710
1711         /* create map in the end of data2 block */
1712         map = (struct dx_map_entry *) (data2 + blocksize);
1713         count = dx_make_map(dir, (struct ext4_dir_entry_2 *) data1,
1714                              blocksize, hinfo, map);
1715         map -= count;
1716         dx_sort_map(map, count);
1717         /* Split the existing block in the middle, size-wise */
1718         size = 0;
1719         move = 0;
1720         for (i = count-1; i >= 0; i--) {
1721                 /* is more than half of this entry in 2nd half of the block? */
1722                 if (size + map[i].size/2 > blocksize/2)
1723                         break;
1724                 size += map[i].size;
1725                 move++;
1726         }
1727         /* map index at which we will split */
1728         split = count - move;
1729         hash2 = map[split].hash;
1730         continued = hash2 == map[split - 1].hash;
1731         dxtrace(printk(KERN_INFO "Split block %lu at %x, %i/%i\n",
1732                         (unsigned long)dx_get_block(frame->at),
1733                                         hash2, split, count-split));
1734
1735         /* Fancy dance to stay within two buffers */
1736         de2 = dx_move_dirents(data1, data2, map + split, count - split,
1737                               blocksize);
1738         de = dx_pack_dirents(data1, blocksize);
1739         de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
1740                                            (char *) de,
1741                                            blocksize);
1742         de2->rec_len = ext4_rec_len_to_disk(data2 + (blocksize - csum_size) -
1743                                             (char *) de2,
1744                                             blocksize);
1745         if (csum_size) {
1746                 t = EXT4_DIRENT_TAIL(data2, blocksize);
1747                 initialize_dirent_tail(t, blocksize);
1748
1749                 t = EXT4_DIRENT_TAIL(data1, blocksize);
1750                 initialize_dirent_tail(t, blocksize);
1751         }
1752
1753         dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data1,
1754                         blocksize, 1));
1755         dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data2,
1756                         blocksize, 1));
1757
1758         /* Which block gets the new entry? */
1759         if (hinfo->hash >= hash2) {
1760                 swap(*bh, bh2);
1761                 de = de2;
1762         }
1763         dx_insert_block(frame, hash2 + continued, newblock);
1764         err = ext4_handle_dirty_dirent_node(handle, dir, bh2);
1765         if (err)
1766                 goto journal_error;
1767         err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
1768         if (err)
1769                 goto journal_error;
1770         brelse(bh2);
1771         dxtrace(dx_show_index("frame", frame->entries));
1772         return de;
1773
1774 journal_error:
1775         brelse(*bh);
1776         brelse(bh2);
1777         *bh = NULL;
1778         ext4_std_error(dir->i_sb, err);
1779         return ERR_PTR(err);
1780 }
1781
1782 int ext4_find_dest_de(struct inode *dir, struct inode *inode,
1783                       struct buffer_head *bh,
1784                       void *buf, int buf_size,
1785                       struct ext4_filename *fname,
1786                       struct ext4_dir_entry_2 **dest_de)
1787 {
1788         struct ext4_dir_entry_2 *de;
1789         unsigned short reclen = EXT4_DIR_REC_LEN(fname_len(fname));
1790         int nlen, rlen;
1791         unsigned int offset = 0;
1792         char *top;
1793
1794         de = (struct ext4_dir_entry_2 *)buf;
1795         top = buf + buf_size - reclen;
1796         while ((char *) de <= top) {
1797                 if (ext4_check_dir_entry(dir, NULL, de, bh,
1798                                          buf, buf_size, offset))
1799                         return -EFSCORRUPTED;
1800                 if (ext4_match(fname, de))
1801                         return -EEXIST;
1802                 nlen = EXT4_DIR_REC_LEN(de->name_len);
1803                 rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
1804                 if ((de->inode ? rlen - nlen : rlen) >= reclen)
1805                         break;
1806                 de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
1807                 offset += rlen;
1808         }
1809         if ((char *) de > top)
1810                 return -ENOSPC;
1811
1812         *dest_de = de;
1813         return 0;
1814 }
1815
1816 void ext4_insert_dentry(struct inode *inode,
1817                         struct ext4_dir_entry_2 *de,
1818                         int buf_size,
1819                         struct ext4_filename *fname)
1820 {
1821
1822         int nlen, rlen;
1823
1824         nlen = EXT4_DIR_REC_LEN(de->name_len);
1825         rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
1826         if (de->inode) {
1827                 struct ext4_dir_entry_2 *de1 =
1828                         (struct ext4_dir_entry_2 *)((char *)de + nlen);
1829                 de1->rec_len = ext4_rec_len_to_disk(rlen - nlen, buf_size);
1830                 de->rec_len = ext4_rec_len_to_disk(nlen, buf_size);
1831                 de = de1;
1832         }
1833         de->file_type = EXT4_FT_UNKNOWN;
1834         de->inode = cpu_to_le32(inode->i_ino);
1835         ext4_set_de_type(inode->i_sb, de, inode->i_mode);
1836         de->name_len = fname_len(fname);
1837         memcpy(de->name, fname_name(fname), fname_len(fname));
1838 }
1839
1840 /*
1841  * Add a new entry into a directory (leaf) block.  If de is non-NULL,
1842  * it points to a directory entry which is guaranteed to be large
1843  * enough for new directory entry.  If de is NULL, then
1844  * add_dirent_to_buf will attempt search the directory block for
1845  * space.  It will return -ENOSPC if no space is available, and -EIO
1846  * and -EEXIST if directory entry already exists.
1847  */
1848 static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
1849                              struct inode *dir,
1850                              struct inode *inode, struct ext4_dir_entry_2 *de,
1851                              struct buffer_head *bh)
1852 {
1853         unsigned int    blocksize = dir->i_sb->s_blocksize;
1854         int             csum_size = 0;
1855         int             err;
1856
1857         if (ext4_has_metadata_csum(inode->i_sb))
1858                 csum_size = sizeof(struct ext4_dir_entry_tail);
1859
1860         if (!de) {
1861                 err = ext4_find_dest_de(dir, inode, bh, bh->b_data,
1862                                         blocksize - csum_size, fname, &de);
1863                 if (err)
1864                         return err;
1865         }
1866         BUFFER_TRACE(bh, "get_write_access");
1867         err = ext4_journal_get_write_access(handle, bh);
1868         if (err) {
1869                 ext4_std_error(dir->i_sb, err);
1870                 return err;
1871         }
1872
1873         /* By now the buffer is marked for journaling */
1874         ext4_insert_dentry(inode, de, blocksize, fname);
1875
1876         /*
1877          * XXX shouldn't update any times until successful
1878          * completion of syscall, but too many callers depend
1879          * on this.
1880          *
1881          * XXX similarly, too many callers depend on
1882          * ext4_new_inode() setting the times, but error
1883          * recovery deletes the inode, so the worst that can
1884          * happen is that the times are slightly out of date
1885          * and/or different from the directory change time.
1886          */
1887         dir->i_mtime = dir->i_ctime = current_time(dir);
1888         ext4_update_dx_flag(dir);
1889         inode_inc_iversion(dir);
1890         ext4_mark_inode_dirty(handle, dir);
1891         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
1892         err = ext4_handle_dirty_dirent_node(handle, dir, bh);
1893         if (err)
1894                 ext4_std_error(dir->i_sb, err);
1895         return 0;
1896 }
1897
1898 /*
1899  * This converts a one block unindexed directory to a 3 block indexed
1900  * directory, and adds the dentry to the indexed directory.
1901  */
1902 static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
1903                             struct inode *dir,
1904                             struct inode *inode, struct buffer_head *bh)
1905 {
1906         struct buffer_head *bh2;
1907         struct dx_root  *root;
1908         struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
1909         struct dx_entry *entries;
1910         struct ext4_dir_entry_2 *de, *de2;
1911         struct ext4_dir_entry_tail *t;
1912         char            *data1, *top;
1913         unsigned        len;
1914         int             retval;
1915         unsigned        blocksize;
1916         ext4_lblk_t  block;
1917         struct fake_dirent *fde;
1918         int csum_size = 0;
1919
1920         if (ext4_has_metadata_csum(inode->i_sb))
1921                 csum_size = sizeof(struct ext4_dir_entry_tail);
1922
1923         blocksize =  dir->i_sb->s_blocksize;
1924         dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino));
1925         BUFFER_TRACE(bh, "get_write_access");
1926         retval = ext4_journal_get_write_access(handle, bh);
1927         if (retval) {
1928                 ext4_std_error(dir->i_sb, retval);
1929                 brelse(bh);
1930                 return retval;
1931         }
1932         root = (struct dx_root *) bh->b_data;
1933
1934         /* The 0th block becomes the root, move the dirents out */
1935         fde = &root->dotdot;
1936         de = (struct ext4_dir_entry_2 *)((char *)fde +
1937                 ext4_rec_len_from_disk(fde->rec_len, blocksize));
1938         if ((char *) de >= (((char *) root) + blocksize)) {
1939                 EXT4_ERROR_INODE(dir, "invalid rec_len for '..'");
1940                 brelse(bh);
1941                 return -EFSCORRUPTED;
1942         }
1943         len = ((char *) root) + (blocksize - csum_size) - (char *) de;
1944
1945         /* Allocate new block for the 0th block's dirents */
1946         bh2 = ext4_append(handle, dir, &block);
1947         if (IS_ERR(bh2)) {
1948                 brelse(bh);
1949                 return PTR_ERR(bh2);
1950         }
1951         ext4_set_inode_flag(dir, EXT4_INODE_INDEX);
1952         data1 = bh2->b_data;
1953
1954         memcpy (data1, de, len);
1955         de = (struct ext4_dir_entry_2 *) data1;
1956         top = data1 + len;
1957         while ((char *)(de2 = ext4_next_entry(de, blocksize)) < top)
1958                 de = de2;
1959         de->rec_len = ext4_rec_len_to_disk(data1 + (blocksize - csum_size) -
1960                                            (char *) de,
1961                                            blocksize);
1962
1963         if (csum_size) {
1964                 t = EXT4_DIRENT_TAIL(data1, blocksize);
1965                 initialize_dirent_tail(t, blocksize);
1966         }
1967
1968         /* Initialize the root; the dot dirents already exist */
1969         de = (struct ext4_dir_entry_2 *) (&root->dotdot);
1970         de->rec_len = ext4_rec_len_to_disk(blocksize - EXT4_DIR_REC_LEN(2),
1971                                            blocksize);
1972         memset (&root->info, 0, sizeof(root->info));
1973         root->info.info_length = sizeof(root->info);
1974         root->info.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
1975         entries = root->entries;
1976         dx_set_block(entries, 1);
1977         dx_set_count(entries, 1);
1978         dx_set_limit(entries, dx_root_limit(dir, sizeof(root->info)));
1979
1980         /* Initialize as for dx_probe */
1981         fname->hinfo.hash_version = root->info.hash_version;
1982         if (fname->hinfo.hash_version <= DX_HASH_TEA)
1983                 fname->hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
1984         fname->hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
1985         ext4fs_dirhash(fname_name(fname), fname_len(fname), &fname->hinfo);
1986
1987         memset(frames, 0, sizeof(frames));
1988         frame = frames;
1989         frame->entries = entries;
1990         frame->at = entries;
1991         frame->bh = bh;
1992
1993         retval = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
1994         if (retval)
1995                 goto out_frames;
1996         retval = ext4_handle_dirty_dirent_node(handle, dir, bh2);
1997         if (retval)
1998                 goto out_frames;
1999
2000         de = do_split(handle,dir, &bh2, frame, &fname->hinfo);
2001         if (IS_ERR(de)) {
2002                 retval = PTR_ERR(de);
2003                 goto out_frames;
2004         }
2005
2006         retval = add_dirent_to_buf(handle, fname, dir, inode, de, bh2);
2007 out_frames:
2008         /*
2009          * Even if the block split failed, we have to properly write
2010          * out all the changes we did so far. Otherwise we can end up
2011          * with corrupted filesystem.
2012          */
2013         if (retval)
2014                 ext4_mark_inode_dirty(handle, dir);
2015         dx_release(frames);
2016         brelse(bh2);
2017         return retval;
2018 }
2019
2020 /*
2021  *      ext4_add_entry()
2022  *
2023  * adds a file entry to the specified directory, using the same
2024  * semantics as ext4_find_entry(). It returns NULL if it failed.
2025  *
2026  * NOTE!! The inode part of 'de' is left at 0 - which means you
2027  * may not sleep between calling this and putting something into
2028  * the entry, as someone else might have used it while you slept.
2029  */
2030 static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
2031                           struct inode *inode)
2032 {
2033         struct inode *dir = d_inode(dentry->d_parent);
2034         struct buffer_head *bh = NULL;
2035         struct ext4_dir_entry_2 *de;
2036         struct ext4_dir_entry_tail *t;
2037         struct super_block *sb;
2038         struct ext4_filename fname;
2039         int     retval;
2040         int     dx_fallback=0;
2041         unsigned blocksize;
2042         ext4_lblk_t block, blocks;
2043         int     csum_size = 0;
2044
2045         if (ext4_has_metadata_csum(inode->i_sb))
2046                 csum_size = sizeof(struct ext4_dir_entry_tail);
2047
2048         sb = dir->i_sb;
2049         blocksize = sb->s_blocksize;
2050         if (!dentry->d_name.len)
2051                 return -EINVAL;
2052
2053         retval = ext4_fname_setup_filename(dir, &dentry->d_name, 0, &fname);
2054         if (retval)
2055                 return retval;
2056
2057         if (ext4_has_inline_data(dir)) {
2058                 retval = ext4_try_add_inline_entry(handle, &fname, dir, inode);
2059                 if (retval < 0)
2060                         goto out;
2061                 if (retval == 1) {
2062                         retval = 0;
2063                         goto out;
2064                 }
2065         }
2066
2067         if (is_dx(dir)) {
2068                 retval = ext4_dx_add_entry(handle, &fname, dir, inode);
2069                 if (!retval || (retval != ERR_BAD_DX_DIR))
2070                         goto out;
2071                 ext4_clear_inode_flag(dir, EXT4_INODE_INDEX);
2072                 dx_fallback++;
2073                 ext4_mark_inode_dirty(handle, dir);
2074         }
2075         blocks = dir->i_size >> sb->s_blocksize_bits;
2076         for (block = 0; block < blocks; block++) {
2077                 bh = ext4_read_dirblock(dir, block, DIRENT);
2078                 if (IS_ERR(bh)) {
2079                         retval = PTR_ERR(bh);
2080                         bh = NULL;
2081                         goto out;
2082                 }
2083                 retval = add_dirent_to_buf(handle, &fname, dir, inode,
2084                                            NULL, bh);
2085                 if (retval != -ENOSPC)
2086                         goto out;
2087
2088                 if (blocks == 1 && !dx_fallback &&
2089                     ext4_has_feature_dir_index(sb)) {
2090                         retval = make_indexed_dir(handle, &fname, dir,
2091                                                   inode, bh);
2092                         bh = NULL; /* make_indexed_dir releases bh */
2093                         goto out;
2094                 }
2095                 brelse(bh);
2096         }
2097         bh = ext4_append(handle, dir, &block);
2098         if (IS_ERR(bh)) {
2099                 retval = PTR_ERR(bh);
2100                 bh = NULL;
2101                 goto out;
2102         }
2103         de = (struct ext4_dir_entry_2 *) bh->b_data;
2104         de->inode = 0;
2105         de->rec_len = ext4_rec_len_to_disk(blocksize - csum_size, blocksize);
2106
2107         if (csum_size) {
2108                 t = EXT4_DIRENT_TAIL(bh->b_data, blocksize);
2109                 initialize_dirent_tail(t, blocksize);
2110         }
2111
2112         retval = add_dirent_to_buf(handle, &fname, dir, inode, de, bh);
2113 out:
2114         ext4_fname_free_filename(&fname);
2115         brelse(bh);
2116         if (retval == 0)
2117                 ext4_set_inode_state(inode, EXT4_STATE_NEWENTRY);
2118         return retval;
2119 }
2120
2121 /*
2122  * Returns 0 for success, or a negative error value
2123  */
2124 static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
2125                              struct inode *dir, struct inode *inode)
2126 {
2127         struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
2128         struct dx_entry *entries, *at;
2129         struct buffer_head *bh;
2130         struct super_block *sb = dir->i_sb;
2131         struct ext4_dir_entry_2 *de;
2132         int restart;
2133         int err;
2134
2135 again:
2136         restart = 0;
2137         frame = dx_probe(fname, dir, NULL, frames);
2138         if (IS_ERR(frame))
2139                 return PTR_ERR(frame);
2140         entries = frame->entries;
2141         at = frame->at;
2142         bh = ext4_read_dirblock(dir, dx_get_block(frame->at), DIRENT);
2143         if (IS_ERR(bh)) {
2144                 err = PTR_ERR(bh);
2145                 bh = NULL;
2146                 goto cleanup;
2147         }
2148
2149         BUFFER_TRACE(bh, "get_write_access");
2150         err = ext4_journal_get_write_access(handle, bh);
2151         if (err)
2152                 goto journal_error;
2153
2154         err = add_dirent_to_buf(handle, fname, dir, inode, NULL, bh);
2155         if (err != -ENOSPC)
2156                 goto cleanup;
2157
2158         err = 0;
2159         /* Block full, should compress but for now just split */
2160         dxtrace(printk(KERN_DEBUG "using %u of %u node entries\n",
2161                        dx_get_count(entries), dx_get_limit(entries)));
2162         /* Need to split index? */
2163         if (dx_get_count(entries) == dx_get_limit(entries)) {
2164                 ext4_lblk_t newblock;
2165                 int levels = frame - frames + 1;
2166                 unsigned int icount;
2167                 int add_level = 1;
2168                 struct dx_entry *entries2;
2169                 struct dx_node *node2;
2170                 struct buffer_head *bh2;
2171
2172                 while (frame > frames) {
2173                         if (dx_get_count((frame - 1)->entries) <
2174                             dx_get_limit((frame - 1)->entries)) {
2175                                 add_level = 0;
2176                                 break;
2177                         }
2178                         frame--; /* split higher index block */
2179                         at = frame->at;
2180                         entries = frame->entries;
2181                         restart = 1;
2182                 }
2183                 if (add_level && levels == ext4_dir_htree_level(sb)) {
2184                         ext4_warning(sb, "Directory (ino: %lu) index full, "
2185                                          "reach max htree level :%d",
2186                                          dir->i_ino, levels);
2187                         if (ext4_dir_htree_level(sb) < EXT4_HTREE_LEVEL) {
2188                                 ext4_warning(sb, "Large directory feature is "
2189                                                  "not enabled on this "
2190                                                  "filesystem");
2191                         }
2192                         err = -ENOSPC;
2193                         goto cleanup;
2194                 }
2195                 icount = dx_get_count(entries);
2196                 bh2 = ext4_append(handle, dir, &newblock);
2197                 if (IS_ERR(bh2)) {
2198                         err = PTR_ERR(bh2);
2199                         goto cleanup;
2200                 }
2201                 node2 = (struct dx_node *)(bh2->b_data);
2202                 entries2 = node2->entries;
2203                 memset(&node2->fake, 0, sizeof(struct fake_dirent));
2204                 node2->fake.rec_len = ext4_rec_len_to_disk(sb->s_blocksize,
2205                                                            sb->s_blocksize);
2206                 BUFFER_TRACE(frame->bh, "get_write_access");
2207                 err = ext4_journal_get_write_access(handle, frame->bh);
2208                 if (err)
2209                         goto journal_error;
2210                 if (!add_level) {
2211                         unsigned icount1 = icount/2, icount2 = icount - icount1;
2212                         unsigned hash2 = dx_get_hash(entries + icount1);
2213                         dxtrace(printk(KERN_DEBUG "Split index %i/%i\n",
2214                                        icount1, icount2));
2215
2216                         BUFFER_TRACE(frame->bh, "get_write_access"); /* index root */
2217                         err = ext4_journal_get_write_access(handle,
2218                                                              (frame - 1)->bh);
2219                         if (err)
2220                                 goto journal_error;
2221
2222                         memcpy((char *) entries2, (char *) (entries + icount1),
2223                                icount2 * sizeof(struct dx_entry));
2224                         dx_set_count(entries, icount1);
2225                         dx_set_count(entries2, icount2);
2226                         dx_set_limit(entries2, dx_node_limit(dir));
2227
2228                         /* Which index block gets the new entry? */
2229                         if (at - entries >= icount1) {
2230                                 frame->at = at = at - entries - icount1 + entries2;
2231                                 frame->entries = entries = entries2;
2232                                 swap(frame->bh, bh2);
2233                         }
2234                         dx_insert_block((frame - 1), hash2, newblock);
2235                         dxtrace(dx_show_index("node", frame->entries));
2236                         dxtrace(dx_show_index("node",
2237                                ((struct dx_node *) bh2->b_data)->entries));
2238                         err = ext4_handle_dirty_dx_node(handle, dir, bh2);
2239                         if (err)
2240                                 goto journal_error;
2241                         brelse (bh2);
2242                         err = ext4_handle_dirty_dx_node(handle, dir,
2243                                                    (frame - 1)->bh);
2244                         if (err)
2245                                 goto journal_error;
2246                         if (restart) {
2247                                 err = ext4_handle_dirty_dx_node(handle, dir,
2248                                                            frame->bh);
2249                                 goto journal_error;
2250                         }
2251                 } else {
2252                         struct dx_root *dxroot;
2253                         memcpy((char *) entries2, (char *) entries,
2254                                icount * sizeof(struct dx_entry));
2255                         dx_set_limit(entries2, dx_node_limit(dir));
2256
2257                         /* Set up root */
2258                         dx_set_count(entries, 1);
2259                         dx_set_block(entries + 0, newblock);
2260                         dxroot = (struct dx_root *)frames[0].bh->b_data;
2261                         dxroot->info.indirect_levels += 1;
2262                         dxtrace(printk(KERN_DEBUG
2263                                        "Creating %d level index...\n",
2264                                        info->indirect_levels));
2265                         err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
2266                         if (err)
2267                                 goto journal_error;
2268                         err = ext4_handle_dirty_dx_node(handle, dir, bh2);
2269                         brelse(bh2);
2270                         restart = 1;
2271                         goto journal_error;
2272                 }
2273         }
2274         de = do_split(handle, dir, &bh, frame, &fname->hinfo);
2275         if (IS_ERR(de)) {
2276                 err = PTR_ERR(de);
2277                 goto cleanup;
2278         }
2279         err = add_dirent_to_buf(handle, fname, dir, inode, de, bh);
2280         goto cleanup;
2281
2282 journal_error:
2283         ext4_std_error(dir->i_sb, err); /* this is a no-op if err == 0 */
2284 cleanup:
2285         brelse(bh);
2286         dx_release(frames);
2287         /* @restart is true means htree-path has been changed, we need to
2288          * repeat dx_probe() to find out valid htree-path
2289          */
2290         if (restart && err == 0)
2291                 goto again;
2292         return err;
2293 }
2294
2295 /*
2296  * ext4_generic_delete_entry deletes a directory entry by merging it
2297  * with the previous entry
2298  */
2299 int ext4_generic_delete_entry(handle_t *handle,
2300                               struct inode *dir,
2301                               struct ext4_dir_entry_2 *de_del,
2302                               struct buffer_head *bh,
2303                               void *entry_buf,
2304                               int buf_size,
2305                               int csum_size)
2306 {
2307         struct ext4_dir_entry_2 *de, *pde;
2308         unsigned int blocksize = dir->i_sb->s_blocksize;
2309         int i;
2310
2311         i = 0;
2312         pde = NULL;
2313         de = (struct ext4_dir_entry_2 *)entry_buf;
2314         while (i < buf_size - csum_size) {
2315                 if (ext4_check_dir_entry(dir, NULL, de, bh,
2316                                          bh->b_data, bh->b_size, i))
2317                         return -EFSCORRUPTED;
2318                 if (de == de_del)  {
2319                         if (pde)
2320                                 pde->rec_len = ext4_rec_len_to_disk(
2321                                         ext4_rec_len_from_disk(pde->rec_len,
2322                                                                blocksize) +
2323                                         ext4_rec_len_from_disk(de->rec_len,
2324                                                                blocksize),
2325                                         blocksize);
2326                         else
2327                                 de->inode = 0;
2328                         inode_inc_iversion(dir);
2329                         return 0;
2330                 }
2331                 i += ext4_rec_len_from_disk(de->rec_len, blocksize);
2332                 pde = de;
2333                 de = ext4_next_entry(de, blocksize);
2334         }
2335         return -ENOENT;
2336 }
2337
2338 static int ext4_delete_entry(handle_t *handle,
2339                              struct inode *dir,
2340                              struct ext4_dir_entry_2 *de_del,
2341                              struct buffer_head *bh)
2342 {
2343         int err, csum_size = 0;
2344
2345         if (ext4_has_inline_data(dir)) {
2346                 int has_inline_data = 1;
2347                 err = ext4_delete_inline_entry(handle, dir, de_del, bh,
2348                                                &has_inline_data);
2349                 if (has_inline_data)
2350                         return err;
2351         }
2352
2353         if (ext4_has_metadata_csum(dir->i_sb))
2354                 csum_size = sizeof(struct ext4_dir_entry_tail);
2355
2356         BUFFER_TRACE(bh, "get_write_access");
2357         err = ext4_journal_get_write_access(handle, bh);
2358         if (unlikely(err))
2359                 goto out;
2360
2361         err = ext4_generic_delete_entry(handle, dir, de_del,
2362                                         bh, bh->b_data,
2363                                         dir->i_sb->s_blocksize, csum_size);
2364         if (err)
2365                 goto out;
2366
2367         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
2368         err = ext4_handle_dirty_dirent_node(handle, dir, bh);
2369         if (unlikely(err))
2370                 goto out;
2371
2372         return 0;
2373 out:
2374         if (err != -ENOENT)
2375                 ext4_std_error(dir->i_sb, err);
2376         return err;
2377 }
2378
2379 /*
2380  * Set directory link count to 1 if nlinks > EXT4_LINK_MAX, or if nlinks == 2
2381  * since this indicates that nlinks count was previously 1 to avoid overflowing
2382  * the 16-bit i_links_count field on disk.  Directories with i_nlink == 1 mean
2383  * that subdirectory link counts are not being maintained accurately.
2384  *
2385  * The caller has already checked for i_nlink overflow in case the DIR_LINK
2386  * feature is not enabled and returned -EMLINK.  The is_dx() check is a proxy
2387  * for checking S_ISDIR(inode) (since the INODE_INDEX feature will not be set
2388  * on regular files) and to avoid creating huge/slow non-HTREE directories.
2389  */
2390 static void ext4_inc_count(handle_t *handle, struct inode *inode)
2391 {
2392         inc_nlink(inode);
2393         if (is_dx(inode) &&
2394             (inode->i_nlink > EXT4_LINK_MAX || inode->i_nlink == 2))
2395                 set_nlink(inode, 1);
2396 }
2397
2398 /*
2399  * If a directory had nlink == 1, then we should let it be 1. This indicates
2400  * directory has >EXT4_LINK_MAX subdirs.
2401  */
2402 static void ext4_dec_count(handle_t *handle, struct inode *inode)
2403 {
2404         if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
2405                 drop_nlink(inode);
2406 }
2407
2408
2409 static int ext4_add_nondir(handle_t *handle,
2410                 struct dentry *dentry, struct inode *inode)
2411 {
2412         int err = ext4_add_entry(handle, dentry, inode);
2413         if (!err) {
2414                 ext4_mark_inode_dirty(handle, inode);
2415                 d_instantiate_new(dentry, inode);
2416                 return 0;
2417         }
2418         drop_nlink(inode);
2419         unlock_new_inode(inode);
2420         iput(inode);
2421         return err;
2422 }
2423
2424 /*
2425  * By the time this is called, we already have created
2426  * the directory cache entry for the new file, but it
2427  * is so far negative - it has no inode.
2428  *
2429  * If the create succeeds, we fill in the inode information
2430  * with d_instantiate().
2431  */
2432 static int ext4_create(struct inode *dir, struct dentry *dentry, umode_t mode,
2433                        bool excl)
2434 {
2435         handle_t *handle;
2436         struct inode *inode;
2437         int err, credits, retries = 0;
2438
2439         err = dquot_initialize(dir);
2440         if (err)
2441                 return err;
2442
2443         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2444                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2445 retry:
2446         inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2447                                             NULL, EXT4_HT_DIR, credits);
2448         handle = ext4_journal_current_handle();
2449         err = PTR_ERR(inode);
2450         if (!IS_ERR(inode)) {
2451                 inode->i_op = &ext4_file_inode_operations;
2452                 inode->i_fop = &ext4_file_operations;
2453                 ext4_set_aops(inode);
2454                 err = ext4_add_nondir(handle, dentry, inode);
2455                 if (!err && IS_DIRSYNC(dir))
2456                         ext4_handle_sync(handle);
2457         }
2458         if (handle)
2459                 ext4_journal_stop(handle);
2460         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2461                 goto retry;
2462         return err;
2463 }
2464
2465 static int ext4_mknod(struct inode *dir, struct dentry *dentry,
2466                       umode_t mode, dev_t rdev)
2467 {
2468         handle_t *handle;
2469         struct inode *inode;
2470         int err, credits, retries = 0;
2471
2472         err = dquot_initialize(dir);
2473         if (err)
2474                 return err;
2475
2476         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2477                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2478 retry:
2479         inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
2480                                             NULL, EXT4_HT_DIR, credits);
2481         handle = ext4_journal_current_handle();
2482         err = PTR_ERR(inode);
2483         if (!IS_ERR(inode)) {
2484                 init_special_inode(inode, inode->i_mode, rdev);
2485                 inode->i_op = &ext4_special_inode_operations;
2486                 err = ext4_add_nondir(handle, dentry, inode);
2487                 if (!err && IS_DIRSYNC(dir))
2488                         ext4_handle_sync(handle);
2489         }
2490         if (handle)
2491                 ext4_journal_stop(handle);
2492         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2493                 goto retry;
2494         return err;
2495 }
2496
2497 static int ext4_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
2498 {
2499         handle_t *handle;
2500         struct inode *inode;
2501         int err, retries = 0;
2502
2503         err = dquot_initialize(dir);
2504         if (err)
2505                 return err;
2506
2507 retry:
2508         inode = ext4_new_inode_start_handle(dir, mode,
2509                                             NULL, 0, NULL,
2510                                             EXT4_HT_DIR,
2511                         EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
2512                           4 + EXT4_XATTR_TRANS_BLOCKS);
2513         handle = ext4_journal_current_handle();
2514         err = PTR_ERR(inode);
2515         if (!IS_ERR(inode)) {
2516                 inode->i_op = &ext4_file_inode_operations;
2517                 inode->i_fop = &ext4_file_operations;
2518                 ext4_set_aops(inode);
2519                 d_tmpfile(dentry, inode);
2520                 err = ext4_orphan_add(handle, inode);
2521                 if (err)
2522                         goto err_unlock_inode;
2523                 mark_inode_dirty(inode);
2524                 unlock_new_inode(inode);
2525         }
2526         if (handle)
2527                 ext4_journal_stop(handle);
2528         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2529                 goto retry;
2530         return err;
2531 err_unlock_inode:
2532         ext4_journal_stop(handle);
2533         unlock_new_inode(inode);
2534         return err;
2535 }
2536
2537 struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
2538                           struct ext4_dir_entry_2 *de,
2539                           int blocksize, int csum_size,
2540                           unsigned int parent_ino, int dotdot_real_len)
2541 {
2542         de->inode = cpu_to_le32(inode->i_ino);
2543         de->name_len = 1;
2544         de->rec_len = ext4_rec_len_to_disk(EXT4_DIR_REC_LEN(de->name_len),
2545                                            blocksize);
2546         strcpy(de->name, ".");
2547         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2548
2549         de = ext4_next_entry(de, blocksize);
2550         de->inode = cpu_to_le32(parent_ino);
2551         de->name_len = 2;
2552         if (!dotdot_real_len)
2553                 de->rec_len = ext4_rec_len_to_disk(blocksize -
2554                                         (csum_size + EXT4_DIR_REC_LEN(1)),
2555                                         blocksize);
2556         else
2557                 de->rec_len = ext4_rec_len_to_disk(
2558                                 EXT4_DIR_REC_LEN(de->name_len), blocksize);
2559         strcpy(de->name, "..");
2560         ext4_set_de_type(inode->i_sb, de, S_IFDIR);
2561
2562         return ext4_next_entry(de, blocksize);
2563 }
2564
2565 static int ext4_init_new_dir(handle_t *handle, struct inode *dir,
2566                              struct inode *inode)
2567 {
2568         struct buffer_head *dir_block = NULL;
2569         struct ext4_dir_entry_2 *de;
2570         struct ext4_dir_entry_tail *t;
2571         ext4_lblk_t block = 0;
2572         unsigned int blocksize = dir->i_sb->s_blocksize;
2573         int csum_size = 0;
2574         int err;
2575
2576         if (ext4_has_metadata_csum(dir->i_sb))
2577                 csum_size = sizeof(struct ext4_dir_entry_tail);
2578
2579         if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2580                 err = ext4_try_create_inline_dir(handle, dir, inode);
2581                 if (err < 0 && err != -ENOSPC)
2582                         goto out;
2583                 if (!err)
2584                         goto out;
2585         }
2586
2587         inode->i_size = 0;
2588         dir_block = ext4_append(handle, inode, &block);
2589         if (IS_ERR(dir_block))
2590                 return PTR_ERR(dir_block);
2591         de = (struct ext4_dir_entry_2 *)dir_block->b_data;
2592         ext4_init_dot_dotdot(inode, de, blocksize, csum_size, dir->i_ino, 0);
2593         set_nlink(inode, 2);
2594         if (csum_size) {
2595                 t = EXT4_DIRENT_TAIL(dir_block->b_data, blocksize);
2596                 initialize_dirent_tail(t, blocksize);
2597         }
2598
2599         BUFFER_TRACE(dir_block, "call ext4_handle_dirty_metadata");
2600         err = ext4_handle_dirty_dirent_node(handle, inode, dir_block);
2601         if (err)
2602                 goto out;
2603         set_buffer_verified(dir_block);
2604 out:
2605         brelse(dir_block);
2606         return err;
2607 }
2608
2609 static int ext4_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
2610 {
2611         handle_t *handle;
2612         struct inode *inode;
2613         int err, credits, retries = 0;
2614
2615         if (EXT4_DIR_LINK_MAX(dir))
2616                 return -EMLINK;
2617
2618         err = dquot_initialize(dir);
2619         if (err)
2620                 return err;
2621
2622         credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
2623                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3);
2624 retry:
2625         inode = ext4_new_inode_start_handle(dir, S_IFDIR | mode,
2626                                             &dentry->d_name,
2627                                             0, NULL, EXT4_HT_DIR, credits);
2628         handle = ext4_journal_current_handle();
2629         err = PTR_ERR(inode);
2630         if (IS_ERR(inode))
2631                 goto out_stop;
2632
2633         inode->i_op = &ext4_dir_inode_operations;
2634         inode->i_fop = &ext4_dir_operations;
2635         err = ext4_init_new_dir(handle, dir, inode);
2636         if (err)
2637                 goto out_clear_inode;
2638         err = ext4_mark_inode_dirty(handle, inode);
2639         if (!err)
2640                 err = ext4_add_entry(handle, dentry, inode);
2641         if (err) {
2642 out_clear_inode:
2643                 clear_nlink(inode);
2644                 unlock_new_inode(inode);
2645                 ext4_mark_inode_dirty(handle, inode);
2646                 iput(inode);
2647                 goto out_stop;
2648         }
2649         ext4_inc_count(handle, dir);
2650         ext4_update_dx_flag(dir);
2651         err = ext4_mark_inode_dirty(handle, dir);
2652         if (err)
2653                 goto out_clear_inode;
2654         d_instantiate_new(dentry, inode);
2655         if (IS_DIRSYNC(dir))
2656                 ext4_handle_sync(handle);
2657
2658 out_stop:
2659         if (handle)
2660                 ext4_journal_stop(handle);
2661         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
2662                 goto retry;
2663         return err;
2664 }
2665
2666 /*
2667  * routine to check that the specified directory is empty (for rmdir)
2668  */
2669 bool ext4_empty_dir(struct inode *inode)
2670 {
2671         unsigned int offset;
2672         struct buffer_head *bh;
2673         struct ext4_dir_entry_2 *de, *de1;
2674         struct super_block *sb;
2675
2676         if (ext4_has_inline_data(inode)) {
2677                 int has_inline_data = 1;
2678                 int ret;
2679
2680                 ret = empty_inline_dir(inode, &has_inline_data);
2681                 if (has_inline_data)
2682                         return ret;
2683         }
2684
2685         sb = inode->i_sb;
2686         if (inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2)) {
2687                 EXT4_ERROR_INODE(inode, "invalid size");
2688                 return true;
2689         }
2690         bh = ext4_read_dirblock(inode, 0, EITHER);
2691         if (IS_ERR(bh))
2692                 return true;
2693
2694         de = (struct ext4_dir_entry_2 *) bh->b_data;
2695         de1 = ext4_next_entry(de, sb->s_blocksize);
2696         if (le32_to_cpu(de->inode) != inode->i_ino ||
2697                         le32_to_cpu(de1->inode) == 0 ||
2698                         strcmp(".", de->name) || strcmp("..", de1->name)) {
2699                 ext4_warning_inode(inode, "directory missing '.' and/or '..'");
2700                 brelse(bh);
2701                 return true;
2702         }
2703         offset = ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize) +
2704                  ext4_rec_len_from_disk(de1->rec_len, sb->s_blocksize);
2705         de = ext4_next_entry(de1, sb->s_blocksize);
2706         while (offset < inode->i_size) {
2707                 if ((void *) de >= (void *) (bh->b_data+sb->s_blocksize)) {
2708                         unsigned int lblock;
2709                         brelse(bh);
2710                         lblock = offset >> EXT4_BLOCK_SIZE_BITS(sb);
2711                         bh = ext4_read_dirblock(inode, lblock, EITHER);
2712                         if (IS_ERR(bh))
2713                                 return true;
2714                         de = (struct ext4_dir_entry_2 *) bh->b_data;
2715                 }
2716                 if (ext4_check_dir_entry(inode, NULL, de, bh,
2717                                          bh->b_data, bh->b_size, offset)) {
2718                         de = (struct ext4_dir_entry_2 *)(bh->b_data +
2719                                                          sb->s_blocksize);
2720                         offset = (offset | (sb->s_blocksize - 1)) + 1;
2721                         continue;
2722                 }
2723                 if (le32_to_cpu(de->inode)) {
2724                         brelse(bh);
2725                         return false;
2726                 }
2727                 offset += ext4_rec_len_from_disk(de->rec_len, sb->s_blocksize);
2728                 de = ext4_next_entry(de, sb->s_blocksize);
2729         }
2730         brelse(bh);
2731         return true;
2732 }
2733
2734 /*
2735  * ext4_orphan_add() links an unlinked or truncated inode into a list of
2736  * such inodes, starting at the superblock, in case we crash before the
2737  * file is closed/deleted, or in case the inode truncate spans multiple
2738  * transactions and the last transaction is not recovered after a crash.
2739  *
2740  * At filesystem recovery time, we walk this list deleting unlinked
2741  * inodes and truncating linked inodes in ext4_orphan_cleanup().
2742  *
2743  * Orphan list manipulation functions must be called under i_mutex unless
2744  * we are just creating the inode or deleting it.
2745  */
2746 int ext4_orphan_add(handle_t *handle, struct inode *inode)
2747 {
2748         struct super_block *sb = inode->i_sb;
2749         struct ext4_sb_info *sbi = EXT4_SB(sb);
2750         struct ext4_iloc iloc;
2751         int err = 0, rc;
2752         bool dirty = false;
2753
2754         if (!sbi->s_journal || is_bad_inode(inode))
2755                 return 0;
2756
2757         WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
2758                      !inode_is_locked(inode));
2759         /*
2760          * Exit early if inode already is on orphan list. This is a big speedup
2761          * since we don't have to contend on the global s_orphan_lock.
2762          */
2763         if (!list_empty(&EXT4_I(inode)->i_orphan))
2764                 return 0;
2765
2766         /*
2767          * Orphan handling is only valid for files with data blocks
2768          * being truncated, or files being unlinked. Note that we either
2769          * hold i_mutex, or the inode can not be referenced from outside,
2770          * so i_nlink should not be bumped due to race
2771          */
2772         J_ASSERT((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
2773                   S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);
2774
2775         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
2776         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
2777         if (err)
2778                 goto out;
2779
2780         err = ext4_reserve_inode_write(handle, inode, &iloc);
2781         if (err)
2782                 goto out;
2783
2784         mutex_lock(&sbi->s_orphan_lock);
2785         /*
2786          * Due to previous errors inode may be already a part of on-disk
2787          * orphan list. If so skip on-disk list modification.
2788          */
2789         if (!NEXT_ORPHAN(inode) || NEXT_ORPHAN(inode) >
2790             (le32_to_cpu(sbi->s_es->s_inodes_count))) {
2791                 /* Insert this inode at the head of the on-disk orphan list */
2792                 NEXT_ORPHAN(inode) = le32_to_cpu(sbi->s_es->s_last_orphan);
2793                 sbi->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
2794                 dirty = true;
2795         }
2796         list_add(&EXT4_I(inode)->i_orphan, &sbi->s_orphan);
2797         mutex_unlock(&sbi->s_orphan_lock);
2798
2799         if (dirty) {
2800                 err = ext4_handle_dirty_super(handle, sb);
2801                 rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
2802                 if (!err)
2803                         err = rc;
2804                 if (err) {
2805                         /*
2806                          * We have to remove inode from in-memory list if
2807                          * addition to on disk orphan list failed. Stray orphan
2808                          * list entries can cause panics at unmount time.
2809                          */
2810                         mutex_lock(&sbi->s_orphan_lock);
2811                         list_del_init(&EXT4_I(inode)->i_orphan);
2812                         mutex_unlock(&sbi->s_orphan_lock);
2813                 }
2814         }
2815         jbd_debug(4, "superblock will point to %lu\n", inode->i_ino);
2816         jbd_debug(4, "orphan inode %lu will point to %d\n",
2817                         inode->i_ino, NEXT_ORPHAN(inode));
2818 out:
2819         ext4_std_error(sb, err);
2820         return err;
2821 }
2822
2823 /*
2824  * ext4_orphan_del() removes an unlinked or truncated inode from the list
2825  * of such inodes stored on disk, because it is finally being cleaned up.
2826  */
2827 int ext4_orphan_del(handle_t *handle, struct inode *inode)
2828 {
2829         struct list_head *prev;
2830         struct ext4_inode_info *ei = EXT4_I(inode);
2831         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2832         __u32 ino_next;
2833         struct ext4_iloc iloc;
2834         int err = 0;
2835
2836         if (!sbi->s_journal && !(sbi->s_mount_state & EXT4_ORPHAN_FS))
2837                 return 0;
2838
2839         WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
2840                      !inode_is_locked(inode));
2841         /* Do this quick check before taking global s_orphan_lock. */
2842         if (list_empty(&ei->i_orphan))
2843                 return 0;
2844
2845         if (handle) {
2846                 /* Grab inode buffer early before taking global s_orphan_lock */
2847                 err = ext4_reserve_inode_write(handle, inode, &iloc);
2848         }
2849
2850         mutex_lock(&sbi->s_orphan_lock);
2851         jbd_debug(4, "remove inode %lu from orphan list\n", inode->i_ino);
2852
2853         prev = ei->i_orphan.prev;
2854         list_del_init(&ei->i_orphan);
2855
2856         /* If we're on an error path, we may not have a valid
2857          * transaction handle with which to update the orphan list on
2858          * disk, but we still need to remove the inode from the linked
2859          * list in memory. */
2860         if (!handle || err) {
2861                 mutex_unlock(&sbi->s_orphan_lock);
2862                 goto out_err;
2863         }
2864
2865         ino_next = NEXT_ORPHAN(inode);
2866         if (prev == &sbi->s_orphan) {
2867                 jbd_debug(4, "superblock will point to %u\n", ino_next);
2868                 BUFFER_TRACE(sbi->s_sbh, "get_write_access");
2869                 err = ext4_journal_get_write_access(handle, sbi->s_sbh);
2870                 if (err) {
2871                         mutex_unlock(&sbi->s_orphan_lock);
2872                         goto out_brelse;
2873                 }
2874                 sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
2875                 mutex_unlock(&sbi->s_orphan_lock);
2876                 err = ext4_handle_dirty_super(handle, inode->i_sb);
2877         } else {
2878                 struct ext4_iloc iloc2;
2879                 struct inode *i_prev =
2880                         &list_entry(prev, struct ext4_inode_info, i_orphan)->vfs_inode;
2881
2882                 jbd_debug(4, "orphan inode %lu will point to %u\n",
2883                           i_prev->i_ino, ino_next);
2884                 err = ext4_reserve_inode_write(handle, i_prev, &iloc2);
2885                 if (err) {
2886                         mutex_unlock(&sbi->s_orphan_lock);
2887                         goto out_brelse;
2888                 }
2889                 NEXT_ORPHAN(i_prev) = ino_next;
2890                 err = ext4_mark_iloc_dirty(handle, i_prev, &iloc2);
2891                 mutex_unlock(&sbi->s_orphan_lock);
2892         }
2893         if (err)
2894                 goto out_brelse;
2895         NEXT_ORPHAN(inode) = 0;
2896         err = ext4_mark_iloc_dirty(handle, inode, &iloc);
2897 out_err:
2898         ext4_std_error(inode->i_sb, err);
2899         return err;
2900
2901 out_brelse:
2902         brelse(iloc.bh);
2903         goto out_err;
2904 }
2905
2906 static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
2907 {
2908         int retval;
2909         struct inode *inode;
2910         struct buffer_head *bh;
2911         struct ext4_dir_entry_2 *de;
2912         handle_t *handle = NULL;
2913
2914         if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
2915                 return -EIO;
2916
2917         /* Initialize quotas before so that eventual writes go in
2918          * separate transaction */
2919         retval = dquot_initialize(dir);
2920         if (retval)
2921                 return retval;
2922         retval = dquot_initialize(d_inode(dentry));
2923         if (retval)
2924                 return retval;
2925
2926         retval = -ENOENT;
2927         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
2928         if (IS_ERR(bh))
2929                 return PTR_ERR(bh);
2930         if (!bh)
2931                 goto end_rmdir;
2932
2933         inode = d_inode(dentry);
2934
2935         retval = -EFSCORRUPTED;
2936         if (le32_to_cpu(de->inode) != inode->i_ino)
2937                 goto end_rmdir;
2938
2939         retval = -ENOTEMPTY;
2940         if (!ext4_empty_dir(inode))
2941                 goto end_rmdir;
2942
2943         handle = ext4_journal_start(dir, EXT4_HT_DIR,
2944                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
2945         if (IS_ERR(handle)) {
2946                 retval = PTR_ERR(handle);
2947                 handle = NULL;
2948                 goto end_rmdir;
2949         }
2950
2951         if (IS_DIRSYNC(dir))
2952                 ext4_handle_sync(handle);
2953
2954         retval = ext4_delete_entry(handle, dir, de, bh);
2955         if (retval)
2956                 goto end_rmdir;
2957         if (!EXT4_DIR_LINK_EMPTY(inode))
2958                 ext4_warning_inode(inode,
2959                              "empty directory '%.*s' has too many links (%u)",
2960                              dentry->d_name.len, dentry->d_name.name,
2961                              inode->i_nlink);
2962         inode_inc_iversion(inode);
2963         clear_nlink(inode);
2964         /* There's no need to set i_disksize: the fact that i_nlink is
2965          * zero will ensure that the right thing happens during any
2966          * recovery. */
2967         inode->i_size = 0;
2968         ext4_orphan_add(handle, inode);
2969         inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
2970         ext4_mark_inode_dirty(handle, inode);
2971         ext4_dec_count(handle, dir);
2972         ext4_update_dx_flag(dir);
2973         ext4_mark_inode_dirty(handle, dir);
2974
2975 end_rmdir:
2976         brelse(bh);
2977         if (handle)
2978                 ext4_journal_stop(handle);
2979         return retval;
2980 }
2981
2982 static int ext4_unlink(struct inode *dir, struct dentry *dentry)
2983 {
2984         int retval;
2985         struct inode *inode;
2986         struct buffer_head *bh;
2987         struct ext4_dir_entry_2 *de;
2988         handle_t *handle = NULL;
2989
2990         if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
2991                 return -EIO;
2992
2993         trace_ext4_unlink_enter(dir, dentry);
2994         /* Initialize quotas before so that eventual writes go
2995          * in separate transaction */
2996         retval = dquot_initialize(dir);
2997         if (retval)
2998                 return retval;
2999         retval = dquot_initialize(d_inode(dentry));
3000         if (retval)
3001                 return retval;
3002
3003         retval = -ENOENT;
3004         bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
3005         if (IS_ERR(bh))
3006                 return PTR_ERR(bh);
3007         if (!bh)
3008                 goto end_unlink;
3009
3010         inode = d_inode(dentry);
3011
3012         retval = -EFSCORRUPTED;
3013         if (le32_to_cpu(de->inode) != inode->i_ino)
3014                 goto end_unlink;
3015
3016         handle = ext4_journal_start(dir, EXT4_HT_DIR,
3017                                     EXT4_DATA_TRANS_BLOCKS(dir->i_sb));
3018         if (IS_ERR(handle)) {
3019                 retval = PTR_ERR(handle);
3020                 handle = NULL;
3021                 goto end_unlink;
3022         }
3023
3024         if (IS_DIRSYNC(dir))
3025                 ext4_handle_sync(handle);
3026
3027         if (inode->i_nlink == 0) {
3028                 ext4_warning_inode(inode, "Deleting file '%.*s' with no links",
3029                                    dentry->d_name.len, dentry->d_name.name);
3030                 set_nlink(inode, 1);
3031         }
3032         retval = ext4_delete_entry(handle, dir, de, bh);
3033         if (retval)
3034                 goto end_unlink;
3035         dir->i_ctime = dir->i_mtime = current_time(dir);
3036         ext4_update_dx_flag(dir);
3037         ext4_mark_inode_dirty(handle, dir);
3038         drop_nlink(inode);
3039         if (!inode->i_nlink)
3040                 ext4_orphan_add(handle, inode);
3041         inode->i_ctime = current_time(inode);
3042         ext4_mark_inode_dirty(handle, inode);
3043
3044 end_unlink:
3045         brelse(bh);
3046         if (handle)
3047                 ext4_journal_stop(handle);
3048         trace_ext4_unlink_exit(dentry, retval);
3049         return retval;
3050 }
3051
3052 static int ext4_symlink(struct inode *dir,
3053                         struct dentry *dentry, const char *symname)
3054 {
3055         handle_t *handle;
3056         struct inode *inode;
3057         int err, len = strlen(symname);
3058         int credits;
3059         struct fscrypt_str disk_link;
3060
3061         if (unlikely(ext4_forced_shutdown(EXT4_SB(dir->i_sb))))
3062                 return -EIO;
3063
3064         err = fscrypt_prepare_symlink(dir, symname, len, dir->i_sb->s_blocksize,
3065                                       &disk_link);
3066         if (err)
3067                 return err;
3068
3069         err = dquot_initialize(dir);
3070         if (err)
3071                 return err;
3072
3073         if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3074                 /*
3075                  * For non-fast symlinks, we just allocate inode and put it on
3076                  * orphan list in the first transaction => we need bitmap,
3077                  * group descriptor, sb, inode block, quota blocks, and
3078                  * possibly selinux xattr blocks.
3079                  */
3080                 credits = 4 + EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
3081                           EXT4_XATTR_TRANS_BLOCKS;
3082         } else {
3083                 /*
3084                  * Fast symlink. We have to add entry to directory
3085                  * (EXT4_DATA_TRANS_BLOCKS + EXT4_INDEX_EXTRA_TRANS_BLOCKS),
3086                  * allocate new inode (bitmap, group descriptor, inode block,
3087                  * quota blocks, sb is already counted in previous macros).
3088                  */
3089                 credits = EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3090                           EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3;
3091         }
3092
3093         inode = ext4_new_inode_start_handle(dir, S_IFLNK|S_IRWXUGO,
3094                                             &dentry->d_name, 0, NULL,
3095                                             EXT4_HT_DIR, credits);
3096         handle = ext4_journal_current_handle();
3097         if (IS_ERR(inode)) {
3098                 if (handle)
3099                         ext4_journal_stop(handle);
3100                 return PTR_ERR(inode);
3101         }
3102
3103         if (IS_ENCRYPTED(inode)) {
3104                 err = fscrypt_encrypt_symlink(inode, symname, len, &disk_link);
3105                 if (err)
3106                         goto err_drop_inode;
3107                 inode->i_op = &ext4_encrypted_symlink_inode_operations;
3108         }
3109
3110         if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
3111                 if (!IS_ENCRYPTED(inode))
3112                         inode->i_op = &ext4_symlink_inode_operations;
3113                 inode_nohighmem(inode);
3114                 ext4_set_aops(inode);
3115                 /*
3116                  * We cannot call page_symlink() with transaction started
3117                  * because it calls into ext4_write_begin() which can wait
3118                  * for transaction commit if we are running out of space
3119                  * and thus we deadlock. So we have to stop transaction now
3120                  * and restart it when symlink contents is written.
3121                  *
3122                  * To keep fs consistent in case of crash, we have to put inode
3123                  * to orphan list in the mean time.
3124                  */
3125                 drop_nlink(inode);
3126                 err = ext4_orphan_add(handle, inode);
3127                 ext4_journal_stop(handle);
3128                 handle = NULL;
3129                 if (err)
3130                         goto err_drop_inode;
3131                 err = __page_symlink(inode, disk_link.name, disk_link.len, 1);
3132                 if (err)
3133                         goto err_drop_inode;
3134                 /*
3135                  * Now inode is being linked into dir (EXT4_DATA_TRANS_BLOCKS
3136                  * + EXT4_INDEX_EXTRA_TRANS_BLOCKS), inode is also modified
3137                  */
3138                 handle = ext4_journal_start(dir, EXT4_HT_DIR,
3139                                 EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3140                                 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 1);
3141                 if (IS_ERR(handle)) {
3142                         err = PTR_ERR(handle);
3143                         handle = NULL;
3144                         goto err_drop_inode;
3145                 }
3146                 set_nlink(inode, 1);
3147                 err = ext4_orphan_del(handle, inode);
3148                 if (err)
3149                         goto err_drop_inode;
3150         } else {
3151                 /* clear the extent format for fast symlink */
3152                 ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
3153                 if (!IS_ENCRYPTED(inode)) {
3154                         inode->i_op = &ext4_fast_symlink_inode_operations;
3155                         inode->i_link = (char *)&EXT4_I(inode)->i_data;
3156                 }
3157                 memcpy((char *)&EXT4_I(inode)->i_data, disk_link.name,
3158                        disk_link.len);
3159                 inode->i_size = disk_link.len - 1;
3160         }
3161         EXT4_I(inode)->i_disksize = inode->i_size;
3162         err = ext4_add_nondir(handle, dentry, inode);
3163         if (!err && IS_DIRSYNC(dir))
3164                 ext4_handle_sync(handle);
3165
3166         if (handle)
3167                 ext4_journal_stop(handle);
3168         goto out_free_encrypted_link;
3169
3170 err_drop_inode:
3171         if (handle)
3172                 ext4_journal_stop(handle);
3173         clear_nlink(inode);
3174         unlock_new_inode(inode);
3175         iput(inode);
3176 out_free_encrypted_link:
3177         if (disk_link.name != (unsigned char *)symname)
3178                 kfree(disk_link.name);
3179         return err;
3180 }
3181
3182 static int ext4_link(struct dentry *old_dentry,
3183                      struct inode *dir, struct dentry *dentry)
3184 {
3185         handle_t *handle;
3186         struct inode *inode = d_inode(old_dentry);
3187         int err, retries = 0;
3188
3189         if (inode->i_nlink >= EXT4_LINK_MAX)
3190                 return -EMLINK;
3191
3192         err = fscrypt_prepare_link(old_dentry, dir, dentry);
3193         if (err)
3194                 return err;
3195
3196         if ((ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT)) &&
3197             (!projid_eq(EXT4_I(dir)->i_projid,
3198                         EXT4_I(old_dentry->d_inode)->i_projid)))
3199                 return -EXDEV;
3200
3201         err = dquot_initialize(dir);
3202         if (err)
3203                 return err;
3204
3205 retry:
3206         handle = ext4_journal_start(dir, EXT4_HT_DIR,
3207                 (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
3208                  EXT4_INDEX_EXTRA_TRANS_BLOCKS) + 1);
3209         if (IS_ERR(handle))
3210                 return PTR_ERR(handle);
3211
3212         if (IS_DIRSYNC(dir))
3213                 ext4_handle_sync(handle);
3214
3215         inode->i_ctime = current_time(inode);
3216         ext4_inc_count(handle, inode);
3217         ihold(inode);
3218
3219         err = ext4_add_entry(handle, dentry, inode);
3220         if (!err) {
3221                 ext4_mark_inode_dirty(handle, inode);
3222                 /* this can happen only for tmpfile being
3223                  * linked the first time
3224                  */
3225                 if (inode->i_nlink == 1)
3226                         ext4_orphan_del(handle, inode);
3227                 d_instantiate(dentry, inode);
3228         } else {
3229                 drop_nlink(inode);
3230                 iput(inode);
3231         }
3232         ext4_journal_stop(handle);
3233         if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
3234                 goto retry;
3235         return err;
3236 }
3237
3238
3239 /*
3240  * Try to find buffer head where contains the parent block.
3241  * It should be the inode block if it is inlined or the 1st block
3242  * if it is a normal dir.
3243  */
3244 static struct buffer_head *ext4_get_first_dir_block(handle_t *handle,
3245                                         struct inode *inode,
3246                                         int *retval,
3247                                         struct ext4_dir_entry_2 **parent_de,
3248                                         int *inlined)
3249 {
3250         struct buffer_head *bh;
3251
3252         if (!ext4_has_inline_data(inode)) {
3253                 bh = ext4_read_dirblock(inode, 0, EITHER);
3254                 if (IS_ERR(bh)) {
3255                         *retval = PTR_ERR(bh);
3256                         return NULL;
3257                 }
3258                 *parent_de = ext4_next_entry(
3259                                         (struct ext4_dir_entry_2 *)bh->b_data,
3260                                         inode->i_sb->s_blocksize);
3261                 return bh;
3262         }
3263
3264         *inlined = 1;
3265         return ext4_get_first_inline_block(inode, parent_de, retval);
3266 }
3267
3268 struct ext4_renament {
3269         struct inode *dir;
3270         struct dentry *dentry;
3271         struct inode *inode;
3272         bool is_dir;
3273         int dir_nlink_delta;
3274
3275         /* entry for "dentry" */
3276         struct buffer_head *bh;
3277         struct ext4_dir_entry_2 *de;
3278         int inlined;
3279
3280         /* entry for ".." in inode if it's a directory */
3281         struct buffer_head *dir_bh;
3282         struct ext4_dir_entry_2 *parent_de;
3283         int dir_inlined;
3284 };
3285
3286 static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent)
3287 {
3288         int retval;
3289
3290         ent->dir_bh = ext4_get_first_dir_block(handle, ent->inode,
3291                                               &retval, &ent->parent_de,
3292                                               &ent->dir_inlined);
3293         if (!ent->dir_bh)
3294                 return retval;
3295         if (le32_to_cpu(ent->parent_de->inode) != ent->dir->i_ino)
3296                 return -EFSCORRUPTED;
3297         BUFFER_TRACE(ent->dir_bh, "get_write_access");
3298         return ext4_journal_get_write_access(handle, ent->dir_bh);
3299 }
3300
3301 static int ext4_rename_dir_finish(handle_t *handle, struct ext4_renament *ent,
3302                                   unsigned dir_ino)
3303 {
3304         int retval;
3305
3306         ent->parent_de->inode = cpu_to_le32(dir_ino);
3307         BUFFER_TRACE(ent->dir_bh, "call ext4_handle_dirty_metadata");
3308         if (!ent->dir_inlined) {
3309                 if (is_dx(ent->inode)) {
3310                         retval = ext4_handle_dirty_dx_node(handle,
3311                                                            ent->inode,
3312                                                            ent->dir_bh);
3313                 } else {
3314                         retval = ext4_handle_dirty_dirent_node(handle,
3315                                                                ent->inode,
3316                                                                ent->dir_bh);
3317                 }
3318         } else {
3319                 retval = ext4_mark_inode_dirty(handle, ent->inode);
3320         }
3321         if (retval) {
3322                 ext4_std_error(ent->dir->i_sb, retval);
3323                 return retval;
3324         }
3325         return 0;
3326 }
3327
3328 static int ext4_setent(handle_t *handle, struct ext4_renament *ent,
3329                        unsigned ino, unsigned file_type)
3330 {
3331         int retval;
3332
3333         BUFFER_TRACE(ent->bh, "get write access");
3334         retval = ext4_journal_get_write_access(handle, ent->bh);
3335         if (retval)
3336                 return retval;
3337         ent->de->inode = cpu_to_le32(ino);
3338         if (ext4_has_feature_filetype(ent->dir->i_sb))
3339                 ent->de->file_type = file_type;
3340         inode_inc_iversion(ent->dir);
3341         ent->dir->i_ctime = ent->dir->i_mtime =
3342                 current_time(ent->dir);
3343         ext4_mark_inode_dirty(handle, ent->dir);
3344         BUFFER_TRACE(ent->bh, "call ext4_handle_dirty_metadata");
3345         if (!ent->inlined) {
3346                 retval = ext4_handle_dirty_dirent_node(handle,
3347                                                        ent->dir, ent->bh);
3348                 if (unlikely(retval)) {
3349                         ext4_std_error(ent->dir->i_sb, retval);
3350                         return retval;
3351                 }
3352         }
3353         brelse(ent->bh);
3354         ent->bh = NULL;
3355
3356         return 0;
3357 }
3358
3359 static int ext4_find_delete_entry(handle_t *handle, struct inode *dir,
3360                                   const struct qstr *d_name)
3361 {
3362         int retval = -ENOENT;
3363         struct buffer_head *bh;
3364         struct ext4_dir_entry_2 *de;
3365
3366         bh = ext4_find_entry(dir, d_name, &de, NULL);
3367         if (IS_ERR(bh))
3368                 return PTR_ERR(bh);
3369         if (bh) {
3370                 retval = ext4_delete_entry(handle, dir, de, bh);
3371                 brelse(bh);
3372         }
3373         return retval;
3374 }
3375
3376 static void ext4_rename_delete(handle_t *handle, struct ext4_renament *ent,
3377                                int force_reread)
3378 {
3379         int retval;
3380         /*
3381          * ent->de could have moved from under us during htree split, so make
3382          * sure that we are deleting the right entry.  We might also be pointing
3383          * to a stale entry in the unused part of ent->bh so just checking inum
3384          * and the name isn't enough.
3385          */
3386         if (le32_to_cpu(ent->de->inode) != ent->inode->i_ino ||
3387             ent->de->name_len != ent->dentry->d_name.len ||
3388             strncmp(ent->de->name, ent->dentry->d_name.name,
3389                     ent->de->name_len) ||
3390             force_reread) {
3391                 retval = ext4_find_delete_entry(handle, ent->dir,
3392                                                 &ent->dentry->d_name);
3393         } else {
3394                 retval = ext4_delete_entry(handle, ent->dir, ent->de, ent->bh);
3395                 if (retval == -ENOENT) {
3396                         retval = ext4_find_delete_entry(handle, ent->dir,
3397                                                         &ent->dentry->d_name);
3398                 }
3399         }
3400
3401         if (retval) {
3402                 ext4_warning_inode(ent->dir,
3403                                    "Deleting old file: nlink %d, error=%d",
3404                                    ent->dir->i_nlink, retval);
3405         }
3406 }
3407
3408 static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
3409 {
3410         if (ent->dir_nlink_delta) {
3411                 if (ent->dir_nlink_delta == -1)
3412                         ext4_dec_count(handle, ent->dir);
3413                 else
3414                         ext4_inc_count(handle, ent->dir);
3415                 ext4_mark_inode_dirty(handle, ent->dir);
3416         }
3417 }
3418
3419 static struct inode *ext4_whiteout_for_rename(struct ext4_renament *ent,
3420                                               int credits, handle_t **h)
3421 {
3422         struct inode *wh;
3423         handle_t *handle;
3424         int retries = 0;
3425
3426         /*
3427          * for inode block, sb block, group summaries,
3428          * and inode bitmap
3429          */
3430         credits += (EXT4_MAXQUOTAS_TRANS_BLOCKS(ent->dir->i_sb) +
3431                     EXT4_XATTR_TRANS_BLOCKS + 4);
3432 retry:
3433         wh = ext4_new_inode_start_handle(ent->dir, S_IFCHR | WHITEOUT_MODE,
3434                                          &ent->dentry->d_name, 0, NULL,
3435                                          EXT4_HT_DIR, credits);
3436
3437         handle = ext4_journal_current_handle();
3438         if (IS_ERR(wh)) {
3439                 if (handle)
3440                         ext4_journal_stop(handle);
3441                 if (PTR_ERR(wh) == -ENOSPC &&
3442                     ext4_should_retry_alloc(ent->dir->i_sb, &retries))
3443                         goto retry;
3444         } else {
3445                 *h = handle;
3446                 init_special_inode(wh, wh->i_mode, WHITEOUT_DEV);
3447                 wh->i_op = &ext4_special_inode_operations;
3448         }
3449         return wh;
3450 }
3451
3452 /*
3453  * Anybody can rename anything with this: the permission checks are left to the
3454  * higher-level routines.
3455  *
3456  * n.b.  old_{dentry,inode) refers to the source dentry/inode
3457  * while new_{dentry,inode) refers to the destination dentry/inode
3458  * This comes from rename(const char *oldpath, const char *newpath)
3459  */
3460 static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
3461                        struct inode *new_dir, struct dentry *new_dentry,
3462                        unsigned int flags)
3463 {
3464         handle_t *handle = NULL;
3465         struct ext4_renament old = {
3466                 .dir = old_dir,
3467                 .dentry = old_dentry,
3468                 .inode = d_inode(old_dentry),
3469         };
3470         struct ext4_renament new = {
3471                 .dir = new_dir,
3472                 .dentry = new_dentry,
3473                 .inode = d_inode(new_dentry),
3474         };
3475         int force_reread;
3476         int retval;
3477         struct inode *whiteout = NULL;
3478         int credits;
3479         u8 old_file_type;
3480
3481         if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT)) &&
3482             (!projid_eq(EXT4_I(new_dir)->i_projid,
3483                         EXT4_I(old_dentry->d_inode)->i_projid)))
3484                 return -EXDEV;
3485
3486         retval = dquot_initialize(old.dir);
3487         if (retval)
3488                 return retval;
3489         retval = dquot_initialize(new.dir);
3490         if (retval)
3491                 return retval;
3492
3493         /* Initialize quotas before so that eventual writes go
3494          * in separate transaction */
3495         if (new.inode) {
3496                 retval = dquot_initialize(new.inode);
3497                 if (retval)
3498                         return retval;
3499         }
3500
3501         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de, NULL);
3502         if (IS_ERR(old.bh))
3503                 return PTR_ERR(old.bh);
3504         /*
3505          *  Check for inode number is _not_ due to possible IO errors.
3506          *  We might rmdir the source, keep it as pwd of some process
3507          *  and merrily kill the link to whatever was created under the
3508          *  same name. Goodbye sticky bit ;-<
3509          */
3510         retval = -ENOENT;
3511         if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3512                 goto end_rename;
3513
3514         new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3515                                  &new.de, &new.inlined);
3516         if (IS_ERR(new.bh)) {
3517                 retval = PTR_ERR(new.bh);
3518                 new.bh = NULL;
3519                 goto end_rename;
3520         }
3521         if (new.bh) {
3522                 if (!new.inode) {
3523                         brelse(new.bh);
3524                         new.bh = NULL;
3525                 }
3526         }
3527         if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC))
3528                 ext4_alloc_da_blocks(old.inode);
3529
3530         credits = (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3531                    EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2);
3532         if (!(flags & RENAME_WHITEOUT)) {
3533                 handle = ext4_journal_start(old.dir, EXT4_HT_DIR, credits);
3534                 if (IS_ERR(handle)) {
3535                         retval = PTR_ERR(handle);
3536                         handle = NULL;
3537                         goto end_rename;
3538                 }
3539         } else {
3540                 whiteout = ext4_whiteout_for_rename(&old, credits, &handle);
3541                 if (IS_ERR(whiteout)) {
3542                         retval = PTR_ERR(whiteout);
3543                         whiteout = NULL;
3544                         goto end_rename;
3545                 }
3546         }
3547
3548         if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3549                 ext4_handle_sync(handle);
3550
3551         if (S_ISDIR(old.inode->i_mode)) {
3552                 if (new.inode) {
3553                         retval = -ENOTEMPTY;
3554                         if (!ext4_empty_dir(new.inode))
3555                                 goto end_rename;
3556                 } else {
3557                         retval = -EMLINK;
3558                         if (new.dir != old.dir && EXT4_DIR_LINK_MAX(new.dir))
3559                                 goto end_rename;
3560                 }
3561                 retval = ext4_rename_dir_prepare(handle, &old);
3562                 if (retval)
3563                         goto end_rename;
3564         }
3565         /*
3566          * If we're renaming a file within an inline_data dir and adding or
3567          * setting the new dirent causes a conversion from inline_data to
3568          * extents/blockmap, we need to force the dirent delete code to
3569          * re-read the directory, or else we end up trying to delete a dirent
3570          * from what is now the extent tree root (or a block map).
3571          */
3572         force_reread = (new.dir->i_ino == old.dir->i_ino &&
3573                         ext4_test_inode_flag(new.dir, EXT4_INODE_INLINE_DATA));
3574
3575         old_file_type = old.de->file_type;
3576         if (whiteout) {
3577                 /*
3578                  * Do this before adding a new entry, so the old entry is sure
3579                  * to be still pointing to the valid old entry.
3580                  */
3581                 retval = ext4_setent(handle, &old, whiteout->i_ino,
3582                                      EXT4_FT_CHRDEV);
3583                 if (retval)
3584                         goto end_rename;
3585                 ext4_mark_inode_dirty(handle, whiteout);
3586         }
3587         if (!new.bh) {
3588                 retval = ext4_add_entry(handle, new.dentry, old.inode);
3589                 if (retval)
3590                         goto end_rename;
3591         } else {
3592                 retval = ext4_setent(handle, &new,
3593                                      old.inode->i_ino, old_file_type);
3594                 if (retval)
3595                         goto end_rename;
3596         }
3597         if (force_reread)
3598                 force_reread = !ext4_test_inode_flag(new.dir,
3599                                                      EXT4_INODE_INLINE_DATA);
3600
3601         /*
3602          * Like most other Unix systems, set the ctime for inodes on a
3603          * rename.
3604          */
3605         old.inode->i_ctime = current_time(old.inode);
3606         ext4_mark_inode_dirty(handle, old.inode);
3607
3608         if (!whiteout) {
3609                 /*
3610                  * ok, that's it
3611                  */
3612                 ext4_rename_delete(handle, &old, force_reread);
3613         }
3614
3615         if (new.inode) {
3616                 ext4_dec_count(handle, new.inode);
3617                 new.inode->i_ctime = current_time(new.inode);
3618         }
3619         old.dir->i_ctime = old.dir->i_mtime = current_time(old.dir);
3620         ext4_update_dx_flag(old.dir);
3621         if (old.dir_bh) {
3622                 retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
3623                 if (retval)
3624                         goto end_rename;
3625
3626                 ext4_dec_count(handle, old.dir);
3627                 if (new.inode) {
3628                         /* checked ext4_empty_dir above, can't have another
3629                          * parent, ext4_dec_count() won't work for many-linked
3630                          * dirs */
3631                         clear_nlink(new.inode);
3632                 } else {
3633                         ext4_inc_count(handle, new.dir);
3634                         ext4_update_dx_flag(new.dir);
3635                         ext4_mark_inode_dirty(handle, new.dir);
3636                 }
3637         }
3638         ext4_mark_inode_dirty(handle, old.dir);
3639         if (new.inode) {
3640                 ext4_mark_inode_dirty(handle, new.inode);
3641                 if (!new.inode->i_nlink)
3642                         ext4_orphan_add(handle, new.inode);
3643         }
3644         retval = 0;
3645
3646 end_rename:
3647         brelse(old.dir_bh);
3648         brelse(old.bh);
3649         brelse(new.bh);
3650         if (whiteout) {
3651                 if (retval)
3652                         drop_nlink(whiteout);
3653                 unlock_new_inode(whiteout);
3654                 iput(whiteout);
3655         }
3656         if (handle)
3657                 ext4_journal_stop(handle);
3658         return retval;
3659 }
3660
3661 static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
3662                              struct inode *new_dir, struct dentry *new_dentry)
3663 {
3664         handle_t *handle = NULL;
3665         struct ext4_renament old = {
3666                 .dir = old_dir,
3667                 .dentry = old_dentry,
3668                 .inode = d_inode(old_dentry),
3669         };
3670         struct ext4_renament new = {
3671                 .dir = new_dir,
3672                 .dentry = new_dentry,
3673                 .inode = d_inode(new_dentry),
3674         };
3675         u8 new_file_type;
3676         int retval;
3677         struct timespec64 ctime;
3678
3679         if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT) &&
3680              !projid_eq(EXT4_I(new_dir)->i_projid,
3681                         EXT4_I(old_dentry->d_inode)->i_projid)) ||
3682             (ext4_test_inode_flag(old_dir, EXT4_INODE_PROJINHERIT) &&
3683              !projid_eq(EXT4_I(old_dir)->i_projid,
3684                         EXT4_I(new_dentry->d_inode)->i_projid)))
3685                 return -EXDEV;
3686
3687         retval = dquot_initialize(old.dir);
3688         if (retval)
3689                 return retval;
3690         retval = dquot_initialize(new.dir);
3691         if (retval)
3692                 return retval;
3693
3694         old.bh = ext4_find_entry(old.dir, &old.dentry->d_name,
3695                                  &old.de, &old.inlined);
3696         if (IS_ERR(old.bh))
3697                 return PTR_ERR(old.bh);
3698         /*
3699          *  Check for inode number is _not_ due to possible IO errors.
3700          *  We might rmdir the source, keep it as pwd of some process
3701          *  and merrily kill the link to whatever was created under the
3702          *  same name. Goodbye sticky bit ;-<
3703          */
3704         retval = -ENOENT;
3705         if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
3706                 goto end_rename;
3707
3708         new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
3709                                  &new.de, &new.inlined);
3710         if (IS_ERR(new.bh)) {
3711                 retval = PTR_ERR(new.bh);
3712                 new.bh = NULL;
3713                 goto end_rename;
3714         }
3715
3716         /* RENAME_EXCHANGE case: old *and* new must both exist */
3717         if (!new.bh || le32_to_cpu(new.de->inode) != new.inode->i_ino)
3718                 goto end_rename;
3719
3720         handle = ext4_journal_start(old.dir, EXT4_HT_DIR,
3721                 (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3722                  2 * EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));
3723         if (IS_ERR(handle)) {
3724                 retval = PTR_ERR(handle);
3725                 handle = NULL;
3726                 goto end_rename;
3727         }
3728
3729         if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3730                 ext4_handle_sync(handle);
3731
3732         if (S_ISDIR(old.inode->i_mode)) {
3733                 old.is_dir = true;
3734                 retval = ext4_rename_dir_prepare(handle, &old);
3735                 if (retval)
3736                         goto end_rename;
3737         }
3738         if (S_ISDIR(new.inode->i_mode)) {
3739                 new.is_dir = true;
3740                 retval = ext4_rename_dir_prepare(handle, &new);
3741                 if (retval)
3742                         goto end_rename;
3743         }
3744
3745         /*
3746          * Other than the special case of overwriting a directory, parents'
3747          * nlink only needs to be modified if this is a cross directory rename.
3748          */
3749         if (old.dir != new.dir && old.is_dir != new.is_dir) {
3750                 old.dir_nlink_delta = old.is_dir ? -1 : 1;
3751                 new.dir_nlink_delta = -old.dir_nlink_delta;
3752                 retval = -EMLINK;
3753                 if ((old.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(old.dir)) ||
3754                     (new.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(new.dir)))
3755                         goto end_rename;
3756         }
3757
3758         new_file_type = new.de->file_type;
3759         retval = ext4_setent(handle, &new, old.inode->i_ino, old.de->file_type);
3760         if (retval)
3761                 goto end_rename;
3762
3763         retval = ext4_setent(handle, &old, new.inode->i_ino, new_file_type);
3764         if (retval)
3765                 goto end_rename;
3766
3767         /*
3768          * Like most other Unix systems, set the ctime for inodes on a
3769          * rename.
3770          */
3771         ctime = current_time(old.inode);
3772         old.inode->i_ctime = ctime;
3773         new.inode->i_ctime = ctime;
3774         ext4_mark_inode_dirty(handle, old.inode);
3775         ext4_mark_inode_dirty(handle, new.inode);
3776
3777         if (old.dir_bh) {
3778                 retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
3779                 if (retval)
3780                         goto end_rename;
3781         }
3782         if (new.dir_bh) {
3783                 retval = ext4_rename_dir_finish(handle, &new, old.dir->i_ino);
3784                 if (retval)
3785                         goto end_rename;
3786         }
3787         ext4_update_dir_count(handle, &old);
3788         ext4_update_dir_count(handle, &new);
3789         retval = 0;
3790
3791 end_rename:
3792         brelse(old.dir_bh);
3793         brelse(new.dir_bh);
3794         brelse(old.bh);
3795         brelse(new.bh);
3796         if (handle)
3797                 ext4_journal_stop(handle);
3798         return retval;
3799 }
3800
3801 static int ext4_rename2(struct inode *old_dir, struct dentry *old_dentry,
3802                         struct inode *new_dir, struct dentry *new_dentry,
3803                         unsigned int flags)
3804 {
3805         int err;
3806
3807         if (unlikely(ext4_forced_shutdown(EXT4_SB(old_dir->i_sb))))
3808                 return -EIO;
3809
3810         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
3811                 return -EINVAL;
3812
3813         err = fscrypt_prepare_rename(old_dir, old_dentry, new_dir, new_dentry,
3814                                      flags);
3815         if (err)
3816                 return err;
3817
3818         if (flags & RENAME_EXCHANGE) {
3819                 return ext4_cross_rename(old_dir, old_dentry,
3820                                          new_dir, new_dentry);
3821         }
3822
3823         return ext4_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
3824 }
3825
3826 /*
3827  * directories can handle most operations...
3828  */
3829 const struct inode_operations ext4_dir_inode_operations = {
3830         .create         = ext4_create,
3831         .lookup         = ext4_lookup,
3832         .link           = ext4_link,
3833         .unlink         = ext4_unlink,
3834         .symlink        = ext4_symlink,
3835         .mkdir          = ext4_mkdir,
3836         .rmdir          = ext4_rmdir,
3837         .mknod          = ext4_mknod,
3838         .tmpfile        = ext4_tmpfile,
3839         .rename         = ext4_rename2,
3840         .setattr        = ext4_setattr,
3841         .getattr        = ext4_getattr,
3842         .listxattr      = ext4_listxattr,
3843         .get_acl        = ext4_get_acl,
3844         .set_acl        = ext4_set_acl,
3845         .fiemap         = ext4_fiemap,
3846 };
3847
3848 const struct inode_operations ext4_special_inode_operations = {
3849         .setattr        = ext4_setattr,
3850         .getattr        = ext4_getattr,
3851         .listxattr      = ext4_listxattr,
3852         .get_acl        = ext4_get_acl,
3853         .set_acl        = ext4_set_acl,
3854 };