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 <linux/xattr.h>
   8 #include "messages.h"
   9 #include "props.h"
  10 #include "btrfs_inode.h"
  11 #include "transaction.h"
  12 #include "ctree.h"
  13 #include "xattr.h"
  14 #include "compression.h"
  15 #include "space-info.h"
  16 #include "fs.h"
  17 #include "accessors.h"
  18 #include "super.h"
  19 #include "dir-item.h"
  20
  21 #define BTRFS_PROP_HANDLERS_HT_BITS 8
  22 static DEFINE_HASHTABLE(prop_handlers_ht, BTRFS_PROP_HANDLERS_HT_BITS);
  23
  24 struct prop_handler {
  25         struct hlist_node node;
  26         const char *xattr_name;
  27         int (*validate)(const struct btrfs_inode *inode, const char *value,
  28                         size_t len);
  29         int (*apply)(struct inode *inode, const char *value, size_t len);
  30         const char *(*extract)(const struct inode *inode);
  31         bool (*ignore)(const struct btrfs_inode *inode);
  32         int inheritable;
  33 };
  34
  35 static const struct hlist_head *find_prop_handlers_by_hash(const u64 hash)
  36 {
  37         struct hlist_head *h;
  38
  39         h = &prop_handlers_ht[hash_min(hash, BTRFS_PROP_HANDLERS_HT_BITS)];
  40         if (hlist_empty(h))
  41                 return NULL;
  42
  43         return h;
  44 }
  45
  46 static const struct prop_handler *
  47 find_prop_handler(const char *name,
  48                   const struct hlist_head *handlers)
  49 {
  50         struct prop_handler *h;
  51
  52         if (!handlers) {
  53                 u64 hash = btrfs_name_hash(name, strlen(name));
  54
  55                 handlers = find_prop_handlers_by_hash(hash);
  56                 if (!handlers)
  57                         return NULL;
  58         }
  59
  60         hlist_for_each_entry(h, handlers, node)
  61                 if (!strcmp(h->xattr_name, name))
  62                         return h;
  63
  64         return NULL;
  65 }
  66
  67 int btrfs_validate_prop(const struct btrfs_inode *inode, const char *name,
  68                         const char *value, size_t value_len)
  69 {
  70         const struct prop_handler *handler;
  71
  72         if (strlen(name) <= XATTR_BTRFS_PREFIX_LEN)
  73                 return -EINVAL;
  74
  75         handler = find_prop_handler(name, NULL);
  76         if (!handler)
  77                 return -EINVAL;
  78
  79         if (value_len == 0)
  80                 return 0;
  81
  82         return handler->validate(inode, value, value_len);
  83 }
  84
  85 /*
  86  * Check if a property should be ignored (not set) for an inode.
  87  *
  88  * @inode:     The target inode.
  89  * @name:      The property's name.
  90  *
  91  * The caller must be sure the given property name is valid, for example by
  92  * having previously called btrfs_validate_prop().
  93  *
  94  * Returns:    true if the property should be ignored for the given inode
  95  *             false if the property must not be ignored for the given inode
  96  */
  97 bool btrfs_ignore_prop(const struct btrfs_inode *inode, const char *name)
  98 {
  99         const struct prop_handler *handler;
 100
 101         handler = find_prop_handler(name, NULL);
 102         ASSERT(handler != NULL);
 103
 104         return handler->ignore(inode);
 105 }
 106
 107 int btrfs_set_prop(struct btrfs_trans_handle *trans, struct btrfs_inode *inode,
 108                    const char *name, const char *value, size_t value_len,
 109                    int flags)
 110 {
 111         const struct prop_handler *handler;
 112         int ret;
 113
 114         handler = find_prop_handler(name, NULL);
 115         if (!handler)
 116                 return -EINVAL;
 117
 118         if (value_len == 0) {
 119                 ret = btrfs_setxattr(trans, &inode->vfs_inode, handler->xattr_name,
 120                                      NULL, 0, flags);
 121                 if (ret)
 122                         return ret;
 123
 124                 ret = handler->apply(&inode->vfs_inode, NULL, 0);
 125                 ASSERT(ret == 0);
 126
 127                 return ret;
 128         }
 129
 130         ret = btrfs_setxattr(trans, &inode->vfs_inode, handler->xattr_name, value,
 131                              value_len, flags);
 132         if (ret)
 133                 return ret;
 134         ret = handler->apply(&inode->vfs_inode, value, value_len);
 135         if (ret) {
 136                 btrfs_setxattr(trans, &inode->vfs_inode, handler->xattr_name, NULL,
 137                                0, flags);
 138                 return ret;
 139         }
 140
 141         set_bit(BTRFS_INODE_HAS_PROPS, &inode->runtime_flags);
 142
 143         return 0;
 144 }
 145
 146 static int iterate_object_props(struct btrfs_root *root,
 147                                 struct btrfs_path *path,
 148                                 u64 objectid,
 149                                 void (*iterator)(void *,
 150                                                  const struct prop_handler *,
 151                                                  const char *,
 152                                                  size_t),
 153                                 void *ctx)
 154 {
 155         int ret;
 156         char *name_buf = NULL;
 157         char *value_buf = NULL;
 158         int name_buf_len = 0;
 159         int value_buf_len = 0;
 160
 161         while (1) {
 162                 struct btrfs_key key;
 163                 struct btrfs_dir_item *di;
 164                 struct extent_buffer *leaf;
 165                 u32 total_len, cur, this_len;
 166                 int slot;
 167                 const struct hlist_head *handlers;
 168
 169                 slot = path->slots[0];
 170                 leaf = path->nodes[0];
 171
 172                 if (slot >= btrfs_header_nritems(leaf)) {
 173                         ret = btrfs_next_leaf(root, path);
 174                         if (ret < 0)
 175                                 goto out;
 176                         else if (ret > 0)
 177                                 break;
 178                         continue;
 179                 }
 180
 181                 btrfs_item_key_to_cpu(leaf, &key, slot);
 182                 if (key.objectid != objectid)
 183                         break;
 184                 if (key.type != BTRFS_XATTR_ITEM_KEY)
 185                         break;
 186
 187                 handlers = find_prop_handlers_by_hash(key.offset);
 188                 if (!handlers)
 189                         goto next_slot;
 190
 191                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
 192                 cur = 0;
 193                 total_len = btrfs_item_size(leaf, slot);
 194
 195                 while (cur < total_len) {
 196                         u32 name_len = btrfs_dir_name_len(leaf, di);
 197                         u32 data_len = btrfs_dir_data_len(leaf, di);
 198                         unsigned long name_ptr, data_ptr;
 199                         const struct prop_handler *handler;
 200
 201                         this_len = sizeof(*di) + name_len + data_len;
 202                         name_ptr = (unsigned long)(di + 1);
 203                         data_ptr = name_ptr + name_len;
 204
 205                         if (name_len <= XATTR_BTRFS_PREFIX_LEN ||
 206                             memcmp_extent_buffer(leaf, XATTR_BTRFS_PREFIX,
 207                                                  name_ptr,
 208                                                  XATTR_BTRFS_PREFIX_LEN))
 209                                 goto next_dir_item;
 210
 211                         if (name_len >= name_buf_len) {
 212                                 kfree(name_buf);
 213                                 name_buf_len = name_len + 1;
 214                                 name_buf = kmalloc(name_buf_len, GFP_NOFS);
 215                                 if (!name_buf) {
 216                                         ret = -ENOMEM;
 217                                         goto out;
 218                                 }
 219                         }
 220                         read_extent_buffer(leaf, name_buf, name_ptr, name_len);
 221                         name_buf[name_len] = '\0';
 222
 223                         handler = find_prop_handler(name_buf, handlers);
 224                         if (!handler)
 225                                 goto next_dir_item;
 226
 227                         if (data_len > value_buf_len) {
 228                                 kfree(value_buf);
 229                                 value_buf_len = data_len;
 230                                 value_buf = kmalloc(data_len, GFP_NOFS);
 231                                 if (!value_buf) {
 232                                         ret = -ENOMEM;
 233                                         goto out;
 234                                 }
 235                         }
 236                         read_extent_buffer(leaf, value_buf, data_ptr, data_len);
 237
 238                         iterator(ctx, handler, value_buf, data_len);
 239 next_dir_item:
 240                         cur += this_len;
 241                         di = (struct btrfs_dir_item *)((char *) di + this_len);
 242                 }
 243
 244 next_slot:
 245                 path->slots[0]++;
 246         }
 247
 248         ret = 0;
 249 out:
 250         btrfs_release_path(path);
 251         kfree(name_buf);
 252         kfree(value_buf);
 253
 254         return ret;
 255 }
 256
 257 static void inode_prop_iterator(void *ctx,
 258                                 const struct prop_handler *handler,
 259                                 const char *value,
 260                                 size_t len)
 261 {
 262         struct inode *inode = ctx;
 263         struct btrfs_root *root = BTRFS_I(inode)->root;
 264         int ret;
 265
 266         ret = handler->apply(inode, value, len);
 267         if (unlikely(ret))
 268                 btrfs_warn(root->fs_info,
 269                            "error applying prop %s to ino %llu (root %llu): %d",
 270                            handler->xattr_name, btrfs_ino(BTRFS_I(inode)),
 271                            btrfs_root_id(root), ret);
 272         else
 273                 set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
 274 }
 275
 276 int btrfs_load_inode_props(struct inode *inode, struct btrfs_path *path)
 277 {
 278         struct btrfs_root *root = BTRFS_I(inode)->root;
 279         u64 ino = btrfs_ino(BTRFS_I(inode));
 280
 281         return iterate_object_props(root, path, ino, inode_prop_iterator, inode);
 282 }
 283
 284 static int prop_compression_validate(const struct btrfs_inode *inode,
 285                                      const char *value, size_t len)
 286 {
 287         if (!btrfs_inode_can_compress(inode))
 288                 return -EINVAL;
 289
 290         if (!value)
 291                 return 0;
 292
 293         if (btrfs_compress_is_valid_type(value, len))
 294                 return 0;
 295
 296         if ((len == 2 && strncmp("no", value, 2) == 0) ||
 297             (len == 4 && strncmp("none", value, 4) == 0))
 298                 return 0;
 299
 300         return -EINVAL;
 301 }
 302
 303 static int prop_compression_apply(struct inode *inode, const char *value,
 304                                   size_t len)
 305 {
 306         struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
 307         int type;
 308
 309         /* Reset to defaults */
 310         if (len == 0) {
 311                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
 312                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
 313                 BTRFS_I(inode)->prop_compress = BTRFS_COMPRESS_NONE;
 314                 return 0;
 315         }
 316
 317         /* Set NOCOMPRESS flag */
 318         if ((len == 2 && strncmp("no", value, 2) == 0) ||
 319             (len == 4 && strncmp("none", value, 4) == 0)) {
 320                 BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 321                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
 322                 BTRFS_I(inode)->prop_compress = BTRFS_COMPRESS_NONE;
 323
 324                 return 0;
 325         }
 326
 327         if (!strncmp("lzo", value, 3)) {
 328                 type = BTRFS_COMPRESS_LZO;
 329                 btrfs_set_fs_incompat(fs_info, COMPRESS_LZO);
 330         } else if (!strncmp("zlib", value, 4)) {
 331                 type = BTRFS_COMPRESS_ZLIB;
 332         } else if (!strncmp("zstd", value, 4)) {
 333                 type = BTRFS_COMPRESS_ZSTD;
 334                 btrfs_set_fs_incompat(fs_info, COMPRESS_ZSTD);
 335         } else {
 336                 return -EINVAL;
 337         }
 338
 339         BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
 340         BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS;
 341         BTRFS_I(inode)->prop_compress = type;
 342
 343         return 0;
 344 }
 345
 346 static bool prop_compression_ignore(const struct btrfs_inode *inode)
 347 {
 348         /*
 349          * Compression only has effect for regular files, and for directories
 350          * we set it just to propagate it to new files created inside them.
 351          * Everything else (symlinks, devices, sockets, fifos) is pointless as
 352          * it will do nothing, so don't waste metadata space on a compression
 353          * xattr for anything that is neither a file nor a directory.
 354          */
 355         if (!S_ISREG(inode->vfs_inode.i_mode) &&
 356             !S_ISDIR(inode->vfs_inode.i_mode))
 357                 return true;
 358
 359         return false;
 360 }
 361
 362 static const char *prop_compression_extract(const struct inode *inode)
 363 {
 364         switch (BTRFS_I(inode)->prop_compress) {
 365         case BTRFS_COMPRESS_ZLIB:
 366         case BTRFS_COMPRESS_LZO:
 367         case BTRFS_COMPRESS_ZSTD:
 368                 return btrfs_compress_type2str(BTRFS_I(inode)->prop_compress);
 369         default:
 370                 break;
 371         }
 372
 373         return NULL;
 374 }
 375
 376 static struct prop_handler prop_handlers[] = {
 377         {
 378                 .xattr_name = XATTR_BTRFS_PREFIX "compression",
 379                 .validate = prop_compression_validate,
 380                 .apply = prop_compression_apply,
 381                 .extract = prop_compression_extract,
 382                 .ignore = prop_compression_ignore,
 383                 .inheritable = 1
 384         },
 385 };
 386
 387 int btrfs_inode_inherit_props(struct btrfs_trans_handle *trans,
 388                               struct inode *inode, const struct inode *parent)
 389 {
 390         struct btrfs_root *root = BTRFS_I(inode)->root;
 391         struct btrfs_fs_info *fs_info = root->fs_info;
 392         int ret;
 393         int i;
 394         bool need_reserve = false;
 395
 396         if (!test_bit(BTRFS_INODE_HAS_PROPS,
 397                       &BTRFS_I(parent)->runtime_flags))
 398                 return 0;
 399
 400         for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
 401                 const struct prop_handler *h = &prop_handlers[i];
 402                 const char *value;
 403                 u64 num_bytes = 0;
 404
 405                 if (!h->inheritable)
 406                         continue;
 407
 408                 if (h->ignore(BTRFS_I(inode)))
 409                         continue;
 410
 411                 value = h->extract(parent);
 412                 if (!value)
 413                         continue;
 414
 415                 /*
 416                  * This is not strictly necessary as the property should be
 417                  * valid, but in case it isn't, don't propagate it further.
 418                  */
 419                 ret = h->validate(BTRFS_I(inode), value, strlen(value));
 420                 if (ret)
 421                         continue;
 422
 423                 /*
 424                  * Currently callers should be reserving 1 item for properties,
 425                  * since we only have 1 property that we currently support.  If
 426                  * we add more in the future we need to try and reserve more
 427                  * space for them.  But we should also revisit how we do space
 428                  * reservations if we do add more properties in the future.
 429                  */
 430                 if (need_reserve) {
 431                         num_bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
 432                         ret = btrfs_block_rsv_add(fs_info, trans->block_rsv,
 433                                                   num_bytes,
 434                                                   BTRFS_RESERVE_NO_FLUSH);
 435                         if (ret)
 436                                 return ret;
 437                 }
 438
 439                 ret = btrfs_setxattr(trans, inode, h->xattr_name, value,
 440                                      strlen(value), 0);
 441                 if (!ret) {
 442                         ret = h->apply(inode, value, strlen(value));
 443                         if (ret)
 444                                 btrfs_setxattr(trans, inode, h->xattr_name,
 445                                                NULL, 0, 0);
 446                         else
 447                                 set_bit(BTRFS_INODE_HAS_PROPS,
 448                                         &BTRFS_I(inode)->runtime_flags);
 449                 }
 450
 451                 if (need_reserve) {
 452                         btrfs_block_rsv_release(fs_info, trans->block_rsv,
 453                                         num_bytes, NULL);
 454                         if (ret)
 455                                 return ret;
 456                 }
 457                 need_reserve = true;
 458         }
 459
 460         return 0;
 461 }
 462
 463 int __init btrfs_props_init(void)
 464 {
 465         int i;
 466
 467         for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
 468                 struct prop_handler *p = &prop_handlers[i];
 469                 u64 h = btrfs_name_hash(p->xattr_name, strlen(p->xattr_name));
 470
 471                 hash_add(prop_handlers_ht, &p->node, h);
 472         }
 473         return 0;
 474 }
 475