fs/btrfs/props.c

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