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 "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 char *value, size_t len);
  21         int (*apply)(struct inode *inode, const char *value, size_t len);
  22         const char *(*extract)(struct inode *inode);
  23         int inheritable;
  24 };
  25
  26 static int prop_compression_validate(const char *value, size_t len);
  27 static int prop_compression_apply(struct inode *inode,
  28                                   const char *value,
  29                                   size_t len);
  30 static const char *prop_compression_extract(struct inode *inode);
  31
  32 static struct prop_handler prop_handlers[] = {
  33         {
  34                 .xattr_name = XATTR_BTRFS_PREFIX "compression",
  35                 .validate = prop_compression_validate,
  36                 .apply = prop_compression_apply,
  37                 .extract = prop_compression_extract,
  38                 .inheritable = 1
  39         },
  40 };
  41
  42 void __init btrfs_props_init(void)
  43 {
  44         int i;
  45
  46         hash_init(prop_handlers_ht);
  47
  48         for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
  49                 struct prop_handler *p = &prop_handlers[i];
  50                 u64 h = btrfs_name_hash(p->xattr_name, strlen(p->xattr_name));
  51
  52                 hash_add(prop_handlers_ht, &p->node, h);
  53         }
  54 }
  55
  56 static const struct hlist_head *find_prop_handlers_by_hash(const u64 hash)
  57 {
  58         struct hlist_head *h;
  59
  60         h = &prop_handlers_ht[hash_min(hash, BTRFS_PROP_HANDLERS_HT_BITS)];
  61         if (hlist_empty(h))
  62                 return NULL;
  63
  64         return h;
  65 }
  66
  67 static const struct prop_handler *
  68 find_prop_handler(const char *name,
  69                   const struct hlist_head *handlers)
  70 {
  71         struct prop_handler *h;
  72
  73         if (!handlers) {
  74                 u64 hash = btrfs_name_hash(name, strlen(name));
  75
  76                 handlers = find_prop_handlers_by_hash(hash);
  77                 if (!handlers)
  78                         return NULL;
  79         }
  80
  81         hlist_for_each_entry(h, handlers, node)
  82                 if (!strcmp(h->xattr_name, name))
  83                         return h;
  84
  85         return NULL;
  86 }
  87
  88 static int __btrfs_set_prop(struct btrfs_trans_handle *trans,
  89                             struct inode *inode,
  90                             const char *name,
  91                             const char *value,
  92                             size_t value_len,
  93                             int flags)
  94 {
  95         const struct prop_handler *handler;
  96         int ret;
  97
  98         if (strlen(name) <= XATTR_BTRFS_PREFIX_LEN)
  99                 return -EINVAL;
 100
 101         handler = find_prop_handler(name, NULL);
 102         if (!handler)
 103                 return -EINVAL;
 104
 105         if (value_len == 0) {
 106                 ret = btrfs_setxattr(trans, inode, handler->xattr_name,
 107                                        NULL, 0, flags);
 108                 if (ret)
 109                         return ret;
 110
 111                 ret = handler->apply(inode, NULL, 0);
 112                 ASSERT(ret == 0);
 113
 114                 return ret;
 115         }
 116
 117         ret = handler->validate(value, value_len);
 118         if (ret)
 119                 return ret;
 120         ret = btrfs_setxattr(trans, inode, handler->xattr_name,
 121                                value, value_len, flags);
 122         if (ret)
 123                 return ret;
 124         ret = handler->apply(inode, value, value_len);
 125         if (ret) {
 126                 btrfs_setxattr(trans, inode, handler->xattr_name,
 127                                  NULL, 0, flags);
 128                 return ret;
 129         }
 130
 131         set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
 132
 133         return 0;
 134 }
 135
 136 int btrfs_set_prop(struct inode *inode,
 137                    const char *name,
 138                    const char *value,
 139                    size_t value_len,
 140                    int flags)
 141 {
 142         return __btrfs_set_prop(NULL, inode, name, value, value_len, flags);
 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_nr(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         int ret;
 280
 281         ret = iterate_object_props(root, path, ino, inode_prop_iterator, inode);
 282
 283         return ret;
 284 }
 285
 286 static int inherit_props(struct btrfs_trans_handle *trans,
 287                          struct inode *inode,
 288                          struct inode *parent)
 289 {
 290         struct btrfs_root *root = BTRFS_I(inode)->root;
 291         struct btrfs_fs_info *fs_info = root->fs_info;
 292         int ret;
 293         int i;
 294
 295         if (!test_bit(BTRFS_INODE_HAS_PROPS,
 296                       &BTRFS_I(parent)->runtime_flags))
 297                 return 0;
 298
 299         for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
 300                 const struct prop_handler *h = &prop_handlers[i];
 301                 const char *value;
 302                 u64 num_bytes;
 303
 304                 if (!h->inheritable)
 305                         continue;
 306
 307                 value = h->extract(parent);
 308                 if (!value)
 309                         continue;
 310
 311                 num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
 312                 ret = btrfs_block_rsv_add(root, trans->block_rsv,
 313                                           num_bytes, BTRFS_RESERVE_NO_FLUSH);
 314                 if (ret)
 315                         goto out;
 316                 ret = __btrfs_set_prop(trans, inode, h->xattr_name,
 317                                        value, strlen(value), 0);
 318                 btrfs_block_rsv_release(fs_info, trans->block_rsv, num_bytes);
 319                 if (ret)
 320                         goto out;
 321         }
 322         ret = 0;
 323 out:
 324         return ret;
 325 }
 326
 327 int btrfs_inode_inherit_props(struct btrfs_trans_handle *trans,
 328                               struct inode *inode,
 329                               struct inode *dir)
 330 {
 331         if (!dir)
 332                 return 0;
 333
 334         return inherit_props(trans, inode, dir);
 335 }
 336
 337 int btrfs_subvol_inherit_props(struct btrfs_trans_handle *trans,
 338                                struct btrfs_root *root,
 339                                struct btrfs_root *parent_root)
 340 {
 341         struct super_block *sb = root->fs_info->sb;
 342         struct btrfs_key key;
 343         struct inode *parent_inode, *child_inode;
 344         int ret;
 345
 346         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
 347         key.type = BTRFS_INODE_ITEM_KEY;
 348         key.offset = 0;
 349
 350         parent_inode = btrfs_iget(sb, &key, parent_root, NULL);
 351         if (IS_ERR(parent_inode))
 352                 return PTR_ERR(parent_inode);
 353
 354         child_inode = btrfs_iget(sb, &key, root, NULL);
 355         if (IS_ERR(child_inode)) {
 356                 iput(parent_inode);
 357                 return PTR_ERR(child_inode);
 358         }
 359
 360         ret = inherit_props(trans, child_inode, parent_inode);
 361         iput(child_inode);
 362         iput(parent_inode);
 363
 364         return ret;
 365 }
 366
 367 static int prop_compression_validate(const char *value, size_t len)
 368 {
 369         if (!strncmp("lzo", value, len))
 370                 return 0;
 371         else if (!strncmp("zlib", value, len))
 372                 return 0;
 373         else if (!strncmp("zstd", value, len))
 374                 return 0;
 375
 376         return -EINVAL;
 377 }
 378
 379 static int prop_compression_apply(struct inode *inode,
 380                                   const char *value,
 381                                   size_t len)
 382 {
 383         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 384         int type;
 385
 386         if (len == 0) {
 387                 BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 388                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
 389                 BTRFS_I(inode)->prop_compress = BTRFS_COMPRESS_NONE;
 390
 391                 return 0;
 392         }
 393
 394         if (!strncmp("lzo", value, 3)) {
 395                 type = BTRFS_COMPRESS_LZO;
 396                 btrfs_set_fs_incompat(fs_info, COMPRESS_LZO);
 397         } else if (!strncmp("zlib", value, 4)) {
 398                 type = BTRFS_COMPRESS_ZLIB;
 399         } else if (!strncmp("zstd", value, len)) {
 400                 type = BTRFS_COMPRESS_ZSTD;
 401                 btrfs_set_fs_incompat(fs_info, COMPRESS_ZSTD);
 402         } else {
 403                 return -EINVAL;
 404         }
 405
 406         BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
 407         BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS;
 408         BTRFS_I(inode)->prop_compress = type;
 409
 410         return 0;
 411 }
 412
 413 static const char *prop_compression_extract(struct inode *inode)
 414 {
 415         switch (BTRFS_I(inode)->prop_compress) {
 416         case BTRFS_COMPRESS_ZLIB:
 417         case BTRFS_COMPRESS_LZO:
 418         case BTRFS_COMPRESS_ZSTD:
 419                 return btrfs_compress_type2str(BTRFS_I(inode)->prop_compress);
 420         default:
 421                 break;
 422         }
 423
 424         return NULL;
 425 }
 426
 427