fs/f2fs/xattr.c

   1 /*
   2  * fs/f2fs/xattr.c
   3  *
   4  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
   5  *             http://www.samsung.com/
   6  *
   7  * Portions of this code from linux/fs/ext2/xattr.c
   8  *
   9  * Copyright (C) 2001-2003 Andreas Gruenbacher <agruen@suse.de>
  10  *
  11  * Fix by Harrison Xing <harrison@mountainviewdata.com>.
  12  * Extended attributes for symlinks and special files added per
  13  *  suggestion of Luka Renko <luka.renko@hermes.si>.
  14  * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
  15  *  Red Hat Inc.
  16  *
  17  * This program is free software; you can redistribute it and/or modify
  18  * it under the terms of the GNU General Public License version 2 as
  19  * published by the Free Software Foundation.
  20  */
  21 #include <linux/rwsem.h>
  22 #include <linux/f2fs_fs.h>
  23 #include "f2fs.h"
  24 #include "xattr.h"
  25
  26 static size_t f2fs_xattr_generic_list(struct dentry *dentry, char *list,
  27                 size_t list_size, const char *name, size_t name_len, int type)
  28 {
  29         struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
  30         int total_len, prefix_len = 0;
  31         const char *prefix = NULL;
  32
  33         switch (type) {
  34         case F2FS_XATTR_INDEX_USER:
  35                 if (!test_opt(sbi, XATTR_USER))
  36                         return -EOPNOTSUPP;
  37                 prefix = XATTR_USER_PREFIX;
  38                 prefix_len = XATTR_USER_PREFIX_LEN;
  39                 break;
  40         case F2FS_XATTR_INDEX_TRUSTED:
  41                 if (!capable(CAP_SYS_ADMIN))
  42                         return -EPERM;
  43                 prefix = XATTR_TRUSTED_PREFIX;
  44                 prefix_len = XATTR_TRUSTED_PREFIX_LEN;
  45                 break;
  46         default:
  47                 return -EINVAL;
  48         }
  49
  50         total_len = prefix_len + name_len + 1;
  51         if (list && total_len <= list_size) {
  52                 memcpy(list, prefix, prefix_len);
  53                 memcpy(list+prefix_len, name, name_len);
  54                 list[prefix_len + name_len] = '\0';
  55         }
  56         return total_len;
  57 }
  58
  59 static int f2fs_xattr_generic_get(struct dentry *dentry, const char *name,
  60                 void *buffer, size_t size, int type)
  61 {
  62         struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
  63
  64         switch (type) {
  65         case F2FS_XATTR_INDEX_USER:
  66                 if (!test_opt(sbi, XATTR_USER))
  67                         return -EOPNOTSUPP;
  68                 break;
  69         case F2FS_XATTR_INDEX_TRUSTED:
  70                 if (!capable(CAP_SYS_ADMIN))
  71                         return -EPERM;
  72                 break;
  73         default:
  74                 return -EINVAL;
  75         }
  76         if (strcmp(name, "") == 0)
  77                 return -EINVAL;
  78         return f2fs_getxattr(dentry->d_inode, type, name,
  79                         buffer, size);
  80 }
  81
  82 static int f2fs_xattr_generic_set(struct dentry *dentry, const char *name,
  83                 const void *value, size_t size, int flags, int type)
  84 {
  85         struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
  86
  87         switch (type) {
  88         case F2FS_XATTR_INDEX_USER:
  89                 if (!test_opt(sbi, XATTR_USER))
  90                         return -EOPNOTSUPP;
  91                 break;
  92         case F2FS_XATTR_INDEX_TRUSTED:
  93                 if (!capable(CAP_SYS_ADMIN))
  94                         return -EPERM;
  95                 break;
  96         default:
  97                 return -EINVAL;
  98         }
  99         if (strcmp(name, "") == 0)
 100                 return -EINVAL;
 101
 102         return f2fs_setxattr(dentry->d_inode, type, name, value, size);
 103 }
 104
 105 static size_t f2fs_xattr_advise_list(struct dentry *dentry, char *list,
 106                 size_t list_size, const char *name, size_t name_len, int type)
 107 {
 108         const char *xname = F2FS_SYSTEM_ADVISE_PREFIX;
 109         size_t size;
 110
 111         if (type != F2FS_XATTR_INDEX_ADVISE)
 112                 return 0;
 113
 114         size = strlen(xname) + 1;
 115         if (list && size <= list_size)
 116                 memcpy(list, xname, size);
 117         return size;
 118 }
 119
 120 static int f2fs_xattr_advise_get(struct dentry *dentry, const char *name,
 121                 void *buffer, size_t size, int type)
 122 {
 123         struct inode *inode = dentry->d_inode;
 124
 125         if (strcmp(name, "") != 0)
 126                 return -EINVAL;
 127
 128         *((char *)buffer) = F2FS_I(inode)->i_advise;
 129         return sizeof(char);
 130 }
 131
 132 static int f2fs_xattr_advise_set(struct dentry *dentry, const char *name,
 133                 const void *value, size_t size, int flags, int type)
 134 {
 135         struct inode *inode = dentry->d_inode;
 136
 137         if (strcmp(name, "") != 0)
 138                 return -EINVAL;
 139         if (!inode_owner_or_capable(inode))
 140                 return -EPERM;
 141         if (value == NULL)
 142                 return -EINVAL;
 143
 144         F2FS_I(inode)->i_advise |= *(char *)value;
 145         return 0;
 146 }
 147
 148 const struct xattr_handler f2fs_xattr_user_handler = {
 149         .prefix = XATTR_USER_PREFIX,
 150         .flags  = F2FS_XATTR_INDEX_USER,
 151         .list   = f2fs_xattr_generic_list,
 152         .get    = f2fs_xattr_generic_get,
 153         .set    = f2fs_xattr_generic_set,
 154 };
 155
 156 const struct xattr_handler f2fs_xattr_trusted_handler = {
 157         .prefix = XATTR_TRUSTED_PREFIX,
 158         .flags  = F2FS_XATTR_INDEX_TRUSTED,
 159         .list   = f2fs_xattr_generic_list,
 160         .get    = f2fs_xattr_generic_get,
 161         .set    = f2fs_xattr_generic_set,
 162 };
 163
 164 const struct xattr_handler f2fs_xattr_advise_handler = {
 165         .prefix = F2FS_SYSTEM_ADVISE_PREFIX,
 166         .flags  = F2FS_XATTR_INDEX_ADVISE,
 167         .list   = f2fs_xattr_advise_list,
 168         .get    = f2fs_xattr_advise_get,
 169         .set    = f2fs_xattr_advise_set,
 170 };
 171
 172 static const struct xattr_handler *f2fs_xattr_handler_map[] = {
 173         [F2FS_XATTR_INDEX_USER] = &f2fs_xattr_user_handler,
 174 #ifdef CONFIG_F2FS_FS_POSIX_ACL
 175         [F2FS_XATTR_INDEX_POSIX_ACL_ACCESS] = &f2fs_xattr_acl_access_handler,
 176         [F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &f2fs_xattr_acl_default_handler,
 177 #endif
 178         [F2FS_XATTR_INDEX_TRUSTED] = &f2fs_xattr_trusted_handler,
 179         [F2FS_XATTR_INDEX_ADVISE] = &f2fs_xattr_advise_handler,
 180 };
 181
 182 const struct xattr_handler *f2fs_xattr_handlers[] = {
 183         &f2fs_xattr_user_handler,
 184 #ifdef CONFIG_F2FS_FS_POSIX_ACL
 185         &f2fs_xattr_acl_access_handler,
 186         &f2fs_xattr_acl_default_handler,
 187 #endif
 188         &f2fs_xattr_trusted_handler,
 189         &f2fs_xattr_advise_handler,
 190         NULL,
 191 };
 192
 193 static inline const struct xattr_handler *f2fs_xattr_handler(int name_index)
 194 {
 195         const struct xattr_handler *handler = NULL;
 196
 197         if (name_index > 0 && name_index < ARRAY_SIZE(f2fs_xattr_handler_map))
 198                 handler = f2fs_xattr_handler_map[name_index];
 199         return handler;
 200 }
 201
 202 int f2fs_getxattr(struct inode *inode, int name_index, const char *name,
 203                 void *buffer, size_t buffer_size)
 204 {
 205         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 206         struct f2fs_inode_info *fi = F2FS_I(inode);
 207         struct f2fs_xattr_entry *entry;
 208         struct page *page;
 209         void *base_addr;
 210         int error = 0, found = 0;
 211         size_t value_len, name_len;
 212
 213         if (name == NULL)
 214                 return -EINVAL;
 215         name_len = strlen(name);
 216
 217         if (!fi->i_xattr_nid)
 218                 return -ENODATA;
 219
 220         page = get_node_page(sbi, fi->i_xattr_nid);
 221         base_addr = page_address(page);
 222
 223         list_for_each_xattr(entry, base_addr) {
 224                 if (entry->e_name_index != name_index)
 225                         continue;
 226                 if (entry->e_name_len != name_len)
 227                         continue;
 228                 if (!memcmp(entry->e_name, name, name_len)) {
 229                         found = 1;
 230                         break;
 231                 }
 232         }
 233         if (!found) {
 234                 error = -ENODATA;
 235                 goto cleanup;
 236         }
 237
 238         value_len = le16_to_cpu(entry->e_value_size);
 239
 240         if (buffer && value_len > buffer_size) {
 241                 error = -ERANGE;
 242                 goto cleanup;
 243         }
 244
 245         if (buffer) {
 246                 char *pval = entry->e_name + entry->e_name_len;
 247                 memcpy(buffer, pval, value_len);
 248         }
 249         error = value_len;
 250
 251 cleanup:
 252         f2fs_put_page(page, 1);
 253         return error;
 254 }
 255
 256 ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 257 {
 258         struct inode *inode = dentry->d_inode;
 259         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 260         struct f2fs_inode_info *fi = F2FS_I(inode);
 261         struct f2fs_xattr_entry *entry;
 262         struct page *page;
 263         void *base_addr;
 264         int error = 0;
 265         size_t rest = buffer_size;
 266
 267         if (!fi->i_xattr_nid)
 268                 return 0;
 269
 270         page = get_node_page(sbi, fi->i_xattr_nid);
 271         base_addr = page_address(page);
 272
 273         list_for_each_xattr(entry, base_addr) {
 274                 const struct xattr_handler *handler =
 275                         f2fs_xattr_handler(entry->e_name_index);
 276                 size_t size;
 277
 278                 if (!handler)
 279                         continue;
 280
 281                 size = handler->list(dentry, buffer, rest, entry->e_name,
 282                                 entry->e_name_len, handler->flags);
 283                 if (buffer && size > rest) {
 284                         error = -ERANGE;
 285                         goto cleanup;
 286                 }
 287
 288                 if (buffer)
 289                         buffer += size;
 290                 rest -= size;
 291         }
 292         error = buffer_size - rest;
 293 cleanup:
 294         f2fs_put_page(page, 1);
 295         return error;
 296 }
 297
 298 int f2fs_setxattr(struct inode *inode, int name_index, const char *name,
 299                                         const void *value, size_t value_len)
 300 {
 301         struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 302         struct f2fs_inode_info *fi = F2FS_I(inode);
 303         struct f2fs_xattr_header *header = NULL;
 304         struct f2fs_xattr_entry *here, *last;
 305         struct page *page;
 306         void *base_addr;
 307         int error, found, free, newsize;
 308         size_t name_len;
 309         char *pval;
 310
 311         if (name == NULL)
 312                 return -EINVAL;
 313         name_len = strlen(name);
 314
 315         if (value == NULL)
 316                 value_len = 0;
 317
 318         if (name_len > 255 || value_len > MAX_VALUE_LEN)
 319                 return -ERANGE;
 320
 321         f2fs_balance_fs(sbi);
 322
 323         mutex_lock_op(sbi, NODE_NEW);
 324         if (!fi->i_xattr_nid) {
 325                 /* Allocate new attribute block */
 326                 struct dnode_of_data dn;
 327
 328                 if (!alloc_nid(sbi, &fi->i_xattr_nid)) {
 329                         mutex_unlock_op(sbi, NODE_NEW);
 330                         return -ENOSPC;
 331                 }
 332                 set_new_dnode(&dn, inode, NULL, NULL, fi->i_xattr_nid);
 333                 mark_inode_dirty(inode);
 334
 335                 page = new_node_page(&dn, XATTR_NODE_OFFSET);
 336                 if (IS_ERR(page)) {
 337                         alloc_nid_failed(sbi, fi->i_xattr_nid);
 338                         fi->i_xattr_nid = 0;
 339                         mutex_unlock_op(sbi, NODE_NEW);
 340                         return PTR_ERR(page);
 341                 }
 342
 343                 alloc_nid_done(sbi, fi->i_xattr_nid);
 344                 base_addr = page_address(page);
 345                 header = XATTR_HDR(base_addr);
 346                 header->h_magic = cpu_to_le32(F2FS_XATTR_MAGIC);
 347                 header->h_refcount = cpu_to_le32(1);
 348         } else {
 349                 /* The inode already has an extended attribute block. */
 350                 page = get_node_page(sbi, fi->i_xattr_nid);
 351                 if (IS_ERR(page)) {
 352                         mutex_unlock_op(sbi, NODE_NEW);
 353                         return PTR_ERR(page);
 354                 }
 355
 356                 base_addr = page_address(page);
 357                 header = XATTR_HDR(base_addr);
 358         }
 359
 360         if (le32_to_cpu(header->h_magic) != F2FS_XATTR_MAGIC) {
 361                 error = -EIO;
 362                 goto cleanup;
 363         }
 364
 365         /* find entry with wanted name. */
 366         found = 0;
 367         list_for_each_xattr(here, base_addr) {
 368                 if (here->e_name_index != name_index)
 369                         continue;
 370                 if (here->e_name_len != name_len)
 371                         continue;
 372                 if (!memcmp(here->e_name, name, name_len)) {
 373                         found = 1;
 374                         break;
 375                 }
 376         }
 377
 378         last = here;
 379
 380         while (!IS_XATTR_LAST_ENTRY(last))
 381                 last = XATTR_NEXT_ENTRY(last);
 382
 383         newsize = XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) +
 384                         name_len + value_len);
 385
 386         /* 1. Check space */
 387         if (value) {
 388                 /* If value is NULL, it is remove operation.
 389                  * In case of update operation, we caculate free.
 390                  */
 391                 free = MIN_OFFSET - ((char *)last - (char *)header);
 392                 if (found)
 393                         free = free - ENTRY_SIZE(here);
 394
 395                 if (free < newsize) {
 396                         error = -ENOSPC;
 397                         goto cleanup;
 398                 }
 399         }
 400
 401         /* 2. Remove old entry */
 402         if (found) {
 403                 /* If entry is found, remove old entry.
 404                  * If not found, remove operation is not needed.
 405                  */
 406                 struct f2fs_xattr_entry *next = XATTR_NEXT_ENTRY(here);
 407                 int oldsize = ENTRY_SIZE(here);
 408
 409                 memmove(here, next, (char *)last - (char *)next);
 410                 last = (struct f2fs_xattr_entry *)((char *)last - oldsize);
 411                 memset(last, 0, oldsize);
 412         }
 413
 414         /* 3. Write new entry */
 415         if (value) {
 416                 /* Before we come here, old entry is removed.
 417                  * We just write new entry. */
 418                 memset(last, 0, newsize);
 419                 last->e_name_index = name_index;
 420                 last->e_name_len = name_len;
 421                 memcpy(last->e_name, name, name_len);
 422                 pval = last->e_name + name_len;
 423                 memcpy(pval, value, value_len);
 424                 last->e_value_size = cpu_to_le16(value_len);
 425         }
 426
 427         set_page_dirty(page);
 428         f2fs_put_page(page, 1);
 429
 430         if (is_inode_flag_set(fi, FI_ACL_MODE)) {
 431                 inode->i_mode = fi->i_acl_mode;
 432                 inode->i_ctime = CURRENT_TIME;
 433                 clear_inode_flag(fi, FI_ACL_MODE);
 434         }
 435         f2fs_write_inode(inode, NULL);
 436         mutex_unlock_op(sbi, NODE_NEW);
 437
 438         return 0;
 439 cleanup:
 440         f2fs_put_page(page, 1);
 441         mutex_unlock_op(sbi, NODE_NEW);
 442         return error;
 443 }