fs/btrfs/props.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2014 Filipe David Borba Manana <[email protected]>
   4  */
   5
   6 #include <linux/hashtable.h>
   7 #include "messages.h"
   8 #include "props.h"
   9 #include "btrfs_inode.h"
  10 #include "transaction.h"
  11 #include "ctree.h"
  12 #include "xattr.h"
  13 #include "compression.h"
  14 #include "space-info.h"
  15 #include "fs.h"
  16 #include "accessors.h"
  17 #include "super.h"
  18 #include "dir-item.h"
  19
  20 #define BTRFS_PROP_HANDLERS_HT_BITS 8
  21 static DEFINE_HASHTABLE(prop_handlers_ht, BTRFS_PROP_HANDLERS_HT_BITS);
  22
  23 struct prop_handler {
  24         struct hlist_node node;
  25         const char *xattr_name;
  26         int (*validate)(const struct btrfs_inode *inode, const char *value,
  27                         size_t len);
  28         int (*apply)(struct inode *inode, const char *value, size_t len);
  29         const char *(*extract)(struct inode *inode);
  30         bool (*ignore)(const struct btrfs_inode *inode);
  31         int inheritable;
  32 };
  33
  34 static const struct hlist_head *find_prop_handlers_by_hash(const u64 hash)
  35 {
  36         struct hlist_head *h;
  37
  38         h = &prop_handlers_ht[hash_min(hash, BTRFS_PROP_HANDLERS_HT_BITS)];
  39         if (hlist_empty(h))
  40                 return NULL;
  41
  42         return h;
  43 }
  44
  45 static const struct prop_handler *
  46 find_prop_handler(const char *name,
  47                   const struct hlist_head *handlers)
  48 {
  49         struct prop_handler *h;
  50
  51         if (!handlers) {
  52                 u64 hash = btrfs_name_hash(name, strlen(name));
  53
  54                 handlers = find_prop_handlers_by_hash(hash);
  55                 if (!handlers)
  56                         return NULL;
  57         }
  58
  59         hlist_for_each_entry(h, handlers, node)
  60                 if (!strcmp(h->xattr_name, name))
  61                         return h;
  62
  63         return NULL;
  64 }
  65
  66 int btrfs_validate_prop(const struct btrfs_inode *inode, const char *name,
  67                         const char *value, size_t value_len)
  68 {
  69         const struct prop_handler *handler;
  70
  71         if (strlen(name) <= XATTR_BTRFS_PREFIX_LEN)
  72                 return -EINVAL;
  73
  74         handler = find_prop_handler(name, NULL);
  75         if (!handler)
  76                 return -EINVAL;
  77
  78         if (value_len == 0)
  79                 return 0;
  80
  81         return handler->validate(inode, value, value_len);
  82 }
  83
  84 /*
  85  * Check if a property should be ignored (not set) for an inode.
  86  *
  87  * @inode:     The target inode.
  88  * @name:      The property's name.
  89  *
  90  * The caller must be sure the given property name is valid, for example by
  91  * having previously called btrfs_validate_prop().
  92  *
  93  * Returns:    true if the property should be ignored for the given inode
  94  *             false if the property must not be ignored for the given inode
  95  */
  96 bool btrfs_ignore_prop(const struct btrfs_inode *inode, const char *name)
  97 {
  98         const struct prop_handler *handler;
  99
 100         handler = find_prop_handler(name, NULL);
 101         ASSERT(handler != NULL);
 102
 103         return handler->ignore(inode);
 104 }
 105
 106 int btrfs_set_prop(struct btrfs_trans_handle *trans, struct inode *inode,
 107                    const char *name, const char *value, size_t value_len,
 108                    int flags)
 109 {
 110         const struct prop_handler *handler;
 111         int ret;
 112
 113         handler = find_prop_handler(name, NULL);
 114         if (!handler)
 115                 return -EINVAL;
 116
 117         if (value_len == 0) {
 118                 ret = btrfs_setxattr(trans, inode, handler->xattr_name,
 119                                      NULL, 0, flags);
 120                 if (ret)
 121                         return ret;
 122
 123                 ret = handler->apply(inode, NULL, 0);
 124                 ASSERT(ret == 0);
 125
 126                 return ret;
 127         }
 128
 129         ret = btrfs_setxattr(trans, inode, handler->xattr_name, value,
 130                              value_len, flags);
 131         if (ret)
 132                 return ret;
 133         ret = handler->apply(inode, value, value_len);
 134         if (ret) {
 135                 btrfs_setxattr(trans, inode, handler->xattr_name, NULL,
 136                                0, flags);
 137                 return ret;
 138         }
 139
 140         set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
 141
 142         return 0;
 143 }
 144
 145 static int iterate_object_props(struct btrfs_root *root,
 146                                 struct btrfs_path *path,
 147                                 u64 objectid,
 148                                 void (*iterator)(void *,
 149                                                  const struct prop_handler *,
 150                                                  const char *,
 151                                                  size_t),
 152                                 void *ctx)
 153 {
 154         int ret;
 155         char *name_buf = NULL;
 156         char *value_buf = NULL;
 157         int name_buf_len = 0;
 158         int value_buf_len = 0;
 159
 160         while (1) {
 161                 struct btrfs_key key;
 162                 struct btrfs_dir_item *di;
 163                 struct extent_buffer *leaf;
 164                 u32 total_len, cur, this_len;
 165                 int slot;
 166                 const struct hlist_head *handlers;
 167
 168                 slot = path->slots[0];
 169                 leaf = path->nodes[0];
 170
 171                 if (slot >= btrfs_header_nritems(leaf)) {
 172                         ret = btrfs_next_leaf(root, path);
 173                         if (ret < 0)
 174                                 goto out;
 175                         else if (ret > 0)
 176                                 break;
 177                         continue;
 178                 }
 179
 180                 btrfs_item_key_to_cpu(leaf, &key, slot);
 181                 if (key.objectid != objectid)
 182                         break;
 183                 if (key.type != BTRFS_XATTR_ITEM_KEY)
 184                         break;
 185
 186                 handlers = find_prop_handlers_by_hash(key.offset);
 187                 if (!handlers)
 188                         goto next_slot;
 189
 190                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
 191                 cur = 0;
 192                 total_len = btrfs_item_size(leaf, slot);
 193
 194                 while (cur < total_len) {
 195                         u32 name_len = btrfs_dir_name_len(leaf, di);
 196                         u32 data_len = btrfs_dir_data_len(leaf, di);
 197                         unsigned long name_ptr, data_ptr;
 198                         const struct prop_handler *handler;
 199
 200                         this_len = sizeof(*di) + name_len + data_len;
 201                         name_ptr = (unsigned long)(di + 1);
 202                         data_ptr = name_ptr + name_len;
 203
 204                         if (name_len <= XATTR_BTRFS_PREFIX_LEN ||
 205                             memcmp_extent_buffer(leaf, XATTR_BTRFS_PREFIX,
 206                                                  name_ptr,
 207                                                  XATTR_BTRFS_PREFIX_LEN))
 208                                 goto next_dir_item;
 209
 210                         if (name_len >= name_buf_len) {
 211                                 kfree(name_buf);
 212                                 name_buf_len = name_len + 1;
 213                                 name_buf = kmalloc(name_buf_len, GFP_NOFS);
 214                                 if (!name_buf) {
 215                                         ret = -ENOMEM;
 216                                         goto out;
 217                                 }
 218                         }
 219                         read_extent_buffer(leaf, name_buf, name_ptr, name_len);
 220                         name_buf[name_len] = '\0';
 221
 222                         handler = find_prop_handler(name_buf, handlers);
 223                         if (!handler)
 224                                 goto next_dir_item;
 225
 226                         if (data_len > value_buf_len) {
 227                                 kfree(value_buf);
 228                                 value_buf_len = data_len;
 229                                 value_buf = kmalloc(data_len, GFP_NOFS);
 230                                 if (!value_buf) {
 231                                         ret = -ENOMEM;
 232                                         goto out;
 233                                 }
 234                         }
 235                         read_extent_buffer(leaf, value_buf, data_ptr, data_len);
 236
 237                         iterator(ctx, handler, value_buf, data_len);
 238 next_dir_item:
 239                         cur += this_len;
 240                         di = (struct btrfs_dir_item *)((char *) di + this_len);
 241                 }
 242
 243 next_slot:
 244                 path->slots[0]++;
 245         }
 246
 247         ret = 0;
 248 out:
 249         btrfs_release_path(path);
 250         kfree(name_buf);
 251         kfree(value_buf);
 252
 253         return ret;
 254 }
 255
 256 static void inode_prop_iterator(void *ctx,
 257                                 const struct prop_handler *handler,
 258                                 const char *value,
 259                                 size_t len)
 260 {
 261         struct inode *inode = ctx;
 262         struct btrfs_root *root = BTRFS_I(inode)->root;
 263         int ret;
 264
 265         ret = handler->apply(inode, value, len);
 266         if (unlikely(ret))
 267                 btrfs_warn(root->fs_info,
 268                            "error applying prop %s to ino %llu (root %llu): %d",
 269                            handler->xattr_name, btrfs_ino(BTRFS_I(inode)),
 270                            root->root_key.objectid, ret);
 271         else
 272                 set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
 273 }
 274
 275 int btrfs_load_inode_props(struct inode *inode, struct btrfs_path *path)
 276 {
 277         struct btrfs_root *root = BTRFS_I(inode)->root;
 278         u64 ino = btrfs_ino(BTRFS_I(inode));
 279
 280         return iterate_object_props(root, path, ino, inode_prop_iterator, inode);
 281 }
 282
 283 static int prop_compression_validate(const struct btrfs_inode *inode,
 284                                      const char *value, size_t len)
 285 {
 286         if (!btrfs_inode_can_compress(inode))
 287                 return -EINVAL;
 288
 289         if (!value)
 290                 return 0;
 291
 292         if (btrfs_compress_is_valid_type(value, len))
 293                 return 0;
 294
 295         if ((len == 2 && strncmp("no", value, 2) == 0) ||
 296             (len == 4 && strncmp("none", value, 4) == 0))
 297                 return 0;
 298
 299         return -EINVAL;
 300 }
 301
 302 static int prop_compression_apply(struct inode *inode, const char *value,
 303                                   size_t len)
 304 {
 305         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 306         int type;
 307
 308         /* Reset to defaults */
 309         if (len == 0) {
 310                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
 311                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
 312                 BTRFS_I(inode)->prop_compress = BTRFS_COMPRESS_NONE;
 313                 return 0;
 314         }
 315
 316         /* Set NOCOMPRESS flag */
 317         if ((len == 2 && strncmp("no", value, 2) == 0) ||
 318             (len == 4 && strncmp("none", value, 4) == 0)) {
 319                 BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 320                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
 321                 BTRFS_I(inode)->prop_compress = BTRFS_COMPRESS_NONE;
 322
 323                 return 0;
 324         }
 325
 326         if (!strncmp("lzo", value, 3)) {
 327                 type = BTRFS_COMPRESS_LZO;
 328                 btrfs_set_fs_incompat(fs_info, COMPRESS_LZO);
 329         } else if (!strncmp("zlib", value, 4)) {
 330                 type = BTRFS_COMPRESS_ZLIB;
 331         } else if (!strncmp("zstd", value, 4)) {
 332                 type = BTRFS_COMPRESS_ZSTD;
 333                 btrfs_set_fs_incompat(fs_info, COMPRESS_ZSTD);
 334         } else {
 335                 return -EINVAL;
 336         }
 337
 338         BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
 339         BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS;
 340         BTRFS_I(inode)->prop_compress = type;
 341
 342         return 0;
 343 }
 344
 345 static bool prop_compression_ignore(const struct btrfs_inode *inode)
 346 {
 347         /*
 348          * Compression only has effect for regular files, and for directories
 349          * we set it just to propagate it to new files created inside them.
 350          * Everything else (symlinks, devices, sockets, fifos) is pointless as
 351          * it will do nothing, so don't waste metadata space on a compression
 352          * xattr for anything that is neither a file nor a directory.
 353          */
 354         if (!S_ISREG(inode->vfs_inode.i_mode) &&
 355             !S_ISDIR(inode->vfs_inode.i_mode))
 356                 return true;
 357
 358         return false;
 359 }
 360
 361 static const char *prop_compression_extract(struct inode *inode)
 362 {
 363         switch (BTRFS_I(inode)->prop_compress) {
 364         case BTRFS_COMPRESS_ZLIB:
 365         case BTRFS_COMPRESS_LZO:
 366         case BTRFS_COMPRESS_ZSTD:
 367                 return btrfs_compress_type2str(BTRFS_I(inode)->prop_compress);
 368         default:
 369                 break;
 370         }
 371
 372         return NULL;
 373 }
 374
 375 static struct prop_handler prop_handlers[] = {
 376         {
 377                 .xattr_name = XATTR_BTRFS_PREFIX "compression",
 378                 .validate = prop_compression_validate,
 379                 .apply = prop_compression_apply,
 380                 .extract = prop_compression_extract,
 381                 .ignore = prop_compression_ignore,
 382                 .inheritable = 1
 383         },
 384 };
 385
 386 int btrfs_inode_inherit_props(struct btrfs_trans_handle *trans,
 387                               struct inode *inode, struct inode *parent)
 388 {
 389         struct btrfs_root *root = BTRFS_I(inode)->root;
 390         struct btrfs_fs_info *fs_info = root->fs_info;
 391         int ret;
 392         int i;
 393         bool need_reserve = false;
 394
 395         if (!test_bit(BTRFS_INODE_HAS_PROPS,
 396                       &BTRFS_I(parent)->runtime_flags))
 397                 return 0;
 398
 399         for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
 400                 const struct prop_handler *h = &prop_handlers[i];
 401                 const char *value;
 402                 u64 num_bytes = 0;
 403
 404                 if (!h->inheritable)
 405                         continue;
 406
 407                 if (h->ignore(BTRFS_I(inode)))
 408                         continue;
 409
 410                 value = h->extract(parent);
 411                 if (!value)
 412                         continue;
 413
 414                 /*
 415                  * This is not strictly necessary as the property should be
 416                  * valid, but in case it isn't, don't propagate it further.
 417                  */
 418                 ret = h->validate(BTRFS_I(inode), value, strlen(value));
 419                 if (ret)
 420                         continue;
 421
 422                 /*
 423                  * Currently callers should be reserving 1 item for properties,
 424                  * since we only have 1 property that we currently support.  If
 425                  * we add more in the future we need to try and reserve more
 426                  * space for them.  But we should also revisit how we do space
 427                  * reservations if we do add more properties in the future.
 428                  */
 429                 if (need_reserve) {
 430                         num_bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
 431                         ret = btrfs_block_rsv_add(fs_info, trans->block_rsv,
 432                                                   num_bytes,
 433                                                   BTRFS_RESERVE_NO_FLUSH);
 434                         if (ret)
 435                                 return ret;
 436                 }
 437
 438                 ret = btrfs_setxattr(trans, inode, h->xattr_name, value,
 439                                      strlen(value), 0);
 440                 if (!ret) {
 441                         ret = h->apply(inode, value, strlen(value));
 442                         if (ret)
 443                                 btrfs_setxattr(trans, inode, h->xattr_name,
 444                                                NULL, 0, 0);
 445                         else
 446                                 set_bit(BTRFS_INODE_HAS_PROPS,
 447                                         &BTRFS_I(inode)->runtime_flags);
 448                 }
 449
 450                 if (need_reserve) {
 451                         btrfs_block_rsv_release(fs_info, trans->block_rsv,
 452                                         num_bytes, NULL);
 453                         if (ret)
 454                                 return ret;
 455                 }
 456                 need_reserve = true;
 457         }
 458
 459         return 0;
 460 }
 461
 462 int __init btrfs_props_init(void)
 463 {
 464         int i;
 465
 466         for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
 467                 struct prop_handler *p = &prop_handlers[i];
 468                 u64 h = btrfs_name_hash(p->xattr_name, strlen(p->xattr_name));
 469
 470                 hash_add(prop_handlers_ht, &p->node, h);
 471         }
 472         return 0;
 473 }
 474