git.sesse.net Git - bcachefs-tools-debian/blob - libbcachefs/dirent.c

   1
   2 #include "bcachefs.h"
   3 #include "bkey_methods.h"
   4 #include "btree_update.h"
   5 #include "extents.h"
   6 #include "dirent.h"
   7 #include "fs.h"
   8 #include "keylist.h"
   9 #include "str_hash.h"
  10
  11 #include <linux/dcache.h>
  12
  13 unsigned bch2_dirent_name_bytes(struct bkey_s_c_dirent d)
  14 {
  15         unsigned len = bkey_val_bytes(d.k) -
  16                 offsetof(struct bch_dirent, d_name);
  17
  18         return strnlen(d.v->d_name, len);
  19 }
  20
  21 static u64 bch2_dirent_hash(const struct bch_hash_info *info,
  22                             const struct qstr *name)
  23 {
  24         struct bch_str_hash_ctx ctx;
  25
  26         bch2_str_hash_init(&ctx, info);
  27         bch2_str_hash_update(&ctx, info, name->name, name->len);
  28
  29         /* [0,2) reserved for dots */
  30         return max_t(u64, bch2_str_hash_end(&ctx, info), 2);
  31 }
  32
  33 static u64 dirent_hash_key(const struct bch_hash_info *info, const void *key)
  34 {
  35         return bch2_dirent_hash(info, key);
  36 }
  37
  38 static u64 dirent_hash_bkey(const struct bch_hash_info *info, struct bkey_s_c k)
  39 {
  40         struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k);
  41         struct qstr name = QSTR_INIT(d.v->d_name, bch2_dirent_name_bytes(d));
  42
  43         return bch2_dirent_hash(info, &name);
  44 }
  45
  46 static bool dirent_cmp_key(struct bkey_s_c _l, const void *_r)
  47 {
  48         struct bkey_s_c_dirent l = bkey_s_c_to_dirent(_l);
  49         int len = bch2_dirent_name_bytes(l);
  50         const struct qstr *r = _r;
  51
  52         return len - r->len ?: memcmp(l.v->d_name, r->name, len);
  53 }
  54
  55 static bool dirent_cmp_bkey(struct bkey_s_c _l, struct bkey_s_c _r)
  56 {
  57         struct bkey_s_c_dirent l = bkey_s_c_to_dirent(_l);
  58         struct bkey_s_c_dirent r = bkey_s_c_to_dirent(_r);
  59         int l_len = bch2_dirent_name_bytes(l);
  60         int r_len = bch2_dirent_name_bytes(r);
  61
  62         return l_len - r_len ?: memcmp(l.v->d_name, r.v->d_name, l_len);
  63 }
  64
  65 const struct bch_hash_desc bch2_dirent_hash_desc = {
  66         .btree_id       = BTREE_ID_DIRENTS,
  67         .key_type       = BCH_DIRENT,
  68         .whiteout_type  = BCH_DIRENT_WHITEOUT,
  69         .hash_key       = dirent_hash_key,
  70         .hash_bkey      = dirent_hash_bkey,
  71         .cmp_key        = dirent_cmp_key,
  72         .cmp_bkey       = dirent_cmp_bkey,
  73 };
  74
  75 const char *bch2_dirent_invalid(const struct bch_fs *c, struct bkey_s_c k)
  76 {
  77         struct bkey_s_c_dirent d;
  78         unsigned len;
  79
  80         switch (k.k->type) {
  81         case BCH_DIRENT:
  82                 if (bkey_val_bytes(k.k) < sizeof(struct bch_dirent))
  83                         return "value too small";
  84
  85                 d = bkey_s_c_to_dirent(k);
  86                 len = bch2_dirent_name_bytes(d);
  87
  88                 if (!len)
  89                         return "empty name";
  90
  91                 /*
  92                  * older versions of bcachefs were buggy and creating dirent
  93                  * keys that were bigger than necessary:
  94                  */
  95                 if (bkey_val_u64s(k.k) > dirent_val_u64s(len + 7))
  96                         return "value too big";
  97
  98                 if (len > BCH_NAME_MAX)
  99                         return "dirent name too big";
 100
 101                 return NULL;
 102         case BCH_DIRENT_WHITEOUT:
 103                 return bkey_val_bytes(k.k) != 0
 104                         ? "value size should be zero"
 105                         : NULL;
 106
 107         default:
 108                 return "invalid type";
 109         }
 110 }
 111
 112 int bch2_dirent_to_text(struct bch_fs *c, char *buf,
 113                         size_t size, struct bkey_s_c k)
 114 {
 115         char *out = buf, *end = buf + size;
 116         struct bkey_s_c_dirent d;
 117
 118         switch (k.k->type) {
 119         case BCH_DIRENT:
 120                 d = bkey_s_c_to_dirent(k);
 121
 122                 out += bch_scnmemcpy(out, end - out, d.v->d_name,
 123                                      bch2_dirent_name_bytes(d));
 124                 out += scnprintf(out, end - out, " -> %llu", d.v->d_inum);
 125                 break;
 126         case BCH_DIRENT_WHITEOUT:
 127                 out += scnprintf(out, end - out, "whiteout");
 128                 break;
 129         }
 130
 131         return out - buf;
 132 }
 133
 134 static struct bkey_i_dirent *dirent_create_key(struct btree_trans *trans,
 135                                 u8 type, const struct qstr *name, u64 dst)
 136 {
 137         struct bkey_i_dirent *dirent;
 138         unsigned u64s = BKEY_U64s + dirent_val_u64s(name->len);
 139
 140         if (name->len > BCH_NAME_MAX)
 141                 return ERR_PTR(-ENAMETOOLONG);
 142
 143         BUG_ON(u64s > U8_MAX);
 144
 145         dirent = bch2_trans_kmalloc(trans, u64s * sizeof(u64));
 146         if (IS_ERR(dirent))
 147                 return dirent;
 148
 149         bkey_dirent_init(&dirent->k_i);
 150         dirent->k.u64s = u64s;
 151         dirent->v.d_inum = cpu_to_le64(dst);
 152         dirent->v.d_type = type;
 153
 154         memcpy(dirent->v.d_name, name->name, name->len);
 155         memset(dirent->v.d_name + name->len, 0,
 156                bkey_val_bytes(&dirent->k) -
 157                offsetof(struct bch_dirent, d_name) -
 158                name->len);
 159
 160         EBUG_ON(bch2_dirent_name_bytes(dirent_i_to_s_c(dirent)) != name->len);
 161
 162         return dirent;
 163 }
 164
 165 int __bch2_dirent_create(struct btree_trans *trans,
 166                          u64 dir_inum, const struct bch_hash_info *hash_info,
 167                          u8 type, const struct qstr *name, u64 dst_inum,
 168                          int flags)
 169 {
 170         struct bkey_i_dirent *dirent;
 171         int ret;
 172
 173         dirent = dirent_create_key(trans, type, name, dst_inum);
 174         ret = PTR_ERR_OR_ZERO(dirent);
 175         if (ret)
 176                 return ret;
 177
 178         return __bch2_hash_set(trans, bch2_dirent_hash_desc, hash_info,
 179                                dir_inum, &dirent->k_i, flags);
 180 }
 181
 182 int bch2_dirent_create(struct bch_fs *c, u64 dir_inum,
 183                        const struct bch_hash_info *hash_info,
 184                        u8 type, const struct qstr *name, u64 dst_inum,
 185                        u64 *journal_seq, int flags)
 186 {
 187         return bch2_trans_do(c, journal_seq, flags,
 188                 __bch2_dirent_create(&trans, dir_inum, hash_info,
 189                                      type, name, dst_inum, flags));
 190 }
 191
 192 static void dirent_copy_target(struct bkey_i_dirent *dst,
 193                                struct bkey_s_c_dirent src)
 194 {
 195         dst->v.d_inum = src.v->d_inum;
 196         dst->v.d_type = src.v->d_type;
 197 }
 198
 199 static struct bpos bch2_dirent_pos(struct bch_inode_info *inode,
 200                                    const struct qstr *name)
 201 {
 202         return POS(inode->v.i_ino, bch2_dirent_hash(&inode->ei_str_hash, name));
 203 }
 204
 205 int bch2_dirent_rename(struct btree_trans *trans,
 206                 struct bch_inode_info *src_dir, const struct qstr *src_name,
 207                 struct bch_inode_info *dst_dir, const struct qstr *dst_name,
 208                 enum bch_rename_mode mode)
 209 {
 210         struct btree_iter *src_iter, *dst_iter;
 211         struct bkey_s_c old_src, old_dst;
 212         struct bkey_i_dirent *new_src = NULL, *new_dst = NULL;
 213         struct bpos dst_pos = bch2_dirent_pos(dst_dir, dst_name);
 214         int ret;
 215
 216         /*
 217          * Lookup dst:
 218          *
 219          * Note that in BCH_RENAME mode, we're _not_ checking if
 220          * the target already exists - we're relying on the VFS
 221          * to do that check for us for correctness:
 222          */
 223         dst_iter = mode == BCH_RENAME
 224                 ? bch2_hash_hole(trans, bch2_dirent_hash_desc,
 225                                  &dst_dir->ei_str_hash,
 226                                  dst_dir->v.i_ino, dst_name)
 227                 : bch2_hash_lookup(trans, bch2_dirent_hash_desc,
 228                                    &dst_dir->ei_str_hash,
 229                                    dst_dir->v.i_ino, dst_name,
 230                                    BTREE_ITER_INTENT);
 231         if (IS_ERR(dst_iter))
 232                 return PTR_ERR(dst_iter);
 233         old_dst = bch2_btree_iter_peek_slot(dst_iter);
 234
 235         /* Lookup src: */
 236         src_iter = bch2_hash_lookup(trans, bch2_dirent_hash_desc,
 237                                     &src_dir->ei_str_hash,
 238                                     src_dir->v.i_ino, src_name,
 239                                     BTREE_ITER_INTENT);
 240         if (IS_ERR(src_iter))
 241                 return PTR_ERR(src_iter);
 242         old_src = bch2_btree_iter_peek_slot(src_iter);
 243
 244         /* Create new dst key: */
 245         new_dst = dirent_create_key(trans, 0, dst_name, 0);
 246         if (IS_ERR(new_dst))
 247                 return PTR_ERR(new_dst);
 248
 249         dirent_copy_target(new_dst, bkey_s_c_to_dirent(old_src));
 250         new_dst->k.p = dst_iter->pos;
 251
 252         /* Create new src key: */
 253         if (mode == BCH_RENAME_EXCHANGE) {
 254                 new_src = dirent_create_key(trans, 0, src_name, 0);
 255                 if (IS_ERR(new_src))
 256                         return PTR_ERR(new_src);
 257
 258                 dirent_copy_target(new_src, bkey_s_c_to_dirent(old_dst));
 259                 new_src->k.p = src_iter->pos;
 260         } else {
 261                 new_src = bch2_trans_kmalloc(trans, sizeof(struct bkey_i));
 262                 if (IS_ERR(new_src))
 263                         return PTR_ERR(new_src);
 264                 bkey_init(&new_src->k);
 265                 new_src->k.p = src_iter->pos;
 266
 267                 if (bkey_cmp(dst_pos, src_iter->pos) <= 0 &&
 268                     bkey_cmp(src_iter->pos, dst_iter->pos) < 0) {
 269                         /*
 270                          * We have a hash collision for the new dst key,
 271                          * and new_src - the key we're deleting - is between
 272                          * new_dst's hashed slot and the slot we're going to be
 273                          * inserting it into - oops.  This will break the hash
 274                          * table if we don't deal with it:
 275                          */
 276                         if (mode == BCH_RENAME) {
 277                                 /*
 278                                  * If we're not overwriting, we can just insert
 279                                  * new_dst at the src position:
 280                                  */
 281                                 new_dst->k.p = src_iter->pos;
 282                                 bch2_trans_update(trans,
 283                                         BTREE_INSERT_ENTRY(src_iter,
 284                                                            &new_dst->k_i));
 285                                 return 0;
 286                         } else {
 287                                 /* If we're overwriting, we can't insert new_dst
 288                                  * at a different slot because it has to
 289                                  * overwrite old_dst - just make sure to use a
 290                                  * whiteout when deleting src:
 291                                  */
 292                                 new_src->k.type = BCH_DIRENT_WHITEOUT;
 293                         }
 294                 } else {
 295                         /* Check if we need a whiteout to delete src: */
 296                         ret = bch2_hash_needs_whiteout(trans, bch2_dirent_hash_desc,
 297                                                        &src_dir->ei_str_hash,
 298                                                        src_iter);
 299                         if (ret < 0)
 300                                 return ret;
 301
 302                         if (ret)
 303                                 new_src->k.type = BCH_DIRENT_WHITEOUT;
 304                 }
 305         }
 306
 307         bch2_trans_update(trans, BTREE_INSERT_ENTRY(src_iter, &new_src->k_i));
 308         bch2_trans_update(trans, BTREE_INSERT_ENTRY(dst_iter, &new_dst->k_i));
 309         return 0;
 310 }
 311
 312 int __bch2_dirent_delete(struct btree_trans *trans, u64 dir_inum,
 313                          const struct bch_hash_info *hash_info,
 314                          const struct qstr *name)
 315 {
 316         return bch2_hash_delete(trans, bch2_dirent_hash_desc, hash_info,
 317                                 dir_inum, name);
 318 }
 319
 320 int bch2_dirent_delete(struct bch_fs *c, u64 dir_inum,
 321                        const struct bch_hash_info *hash_info,
 322                        const struct qstr *name,
 323                        u64 *journal_seq)
 324 {
 325         return bch2_trans_do(c, journal_seq,
 326                              BTREE_INSERT_ATOMIC|
 327                              BTREE_INSERT_NOFAIL,
 328                 __bch2_dirent_delete(&trans, dir_inum, hash_info, name));
 329 }
 330
 331 u64 bch2_dirent_lookup(struct bch_fs *c, u64 dir_inum,
 332                        const struct bch_hash_info *hash_info,
 333                        const struct qstr *name)
 334 {
 335         struct btree_trans trans;
 336         struct btree_iter *iter;
 337         struct bkey_s_c k;
 338         u64 inum = 0;
 339
 340         bch2_trans_init(&trans, c);
 341
 342         iter = bch2_hash_lookup(&trans, bch2_dirent_hash_desc,
 343                                 hash_info, dir_inum, name, 0);
 344         if (IS_ERR(iter)) {
 345                 BUG_ON(PTR_ERR(iter) == -EINTR);
 346                 goto out;
 347         }
 348
 349         k = bch2_btree_iter_peek_slot(iter);
 350         inum = le64_to_cpu(bkey_s_c_to_dirent(k).v->d_inum);
 351 out:
 352         bch2_trans_exit(&trans);
 353         return inum;
 354 }
 355
 356 int bch2_empty_dir(struct bch_fs *c, u64 dir_inum)
 357 {
 358         struct btree_iter iter;
 359         struct bkey_s_c k;
 360         int ret = 0;
 361
 362         for_each_btree_key(&iter, c, BTREE_ID_DIRENTS, POS(dir_inum, 0), 0, k) {
 363                 if (k.k->p.inode > dir_inum)
 364                         break;
 365
 366                 if (k.k->type == BCH_DIRENT) {
 367                         ret = -ENOTEMPTY;
 368                         break;
 369                 }
 370         }
 371         bch2_btree_iter_unlock(&iter);
 372
 373         return ret;
 374 }
 375
 376 int bch2_readdir(struct bch_fs *c, struct file *file,
 377                  struct dir_context *ctx)
 378 {
 379         struct bch_inode_info *inode = file_bch_inode(file);
 380         struct btree_iter iter;
 381         struct bkey_s_c k;
 382         struct bkey_s_c_dirent dirent;
 383         unsigned len;
 384
 385         if (!dir_emit_dots(file, ctx))
 386                 return 0;
 387
 388         for_each_btree_key(&iter, c, BTREE_ID_DIRENTS,
 389                            POS(inode->v.i_ino, ctx->pos), 0, k) {
 390                 if (k.k->type != BCH_DIRENT)
 391                         continue;
 392
 393                 dirent = bkey_s_c_to_dirent(k);
 394
 395                 if (bkey_cmp(k.k->p, POS(inode->v.i_ino, ctx->pos)) < 0)
 396                         continue;
 397
 398                 if (k.k->p.inode > inode->v.i_ino)
 399                         break;
 400
 401                 len = bch2_dirent_name_bytes(dirent);
 402
 403                 /*
 404                  * XXX: dir_emit() can fault and block, while we're holding
 405                  * locks
 406                  */
 407                 if (!dir_emit(ctx, dirent.v->d_name, len,
 408                               le64_to_cpu(dirent.v->d_inum),
 409                               dirent.v->d_type))
 410                         break;
 411
 412                 ctx->pos = k.k->p.offset + 1;
 413         }
 414         bch2_btree_iter_unlock(&iter);
 415
 416         return 0;
 417 }