| 1 | /* |
| 2 | * linux/fs/reiserfs/xattr.c |
| 3 | * |
| 4 | * Copyright (c) 2002 by Jeff Mahoney, <jeffm@suse.com> |
| 5 | * |
| 6 | */ |
| 7 | |
| 8 | /* |
| 9 | * In order to implement EA/ACLs in a clean, backwards compatible manner, |
| 10 | * they are implemented as files in a "private" directory. |
| 11 | * Each EA is in it's own file, with the directory layout like so (/ is assumed |
| 12 | * to be relative to fs root). Inside the /.reiserfs_priv/xattrs directory, |
| 13 | * directories named using the capital-hex form of the objectid and |
| 14 | * generation number are used. Inside each directory are individual files |
| 15 | * named with the name of the extended attribute. |
| 16 | * |
| 17 | * So, for objectid 12648430, we could have: |
| 18 | * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_access |
| 19 | * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_default |
| 20 | * /.reiserfs_priv/xattrs/C0FFEE.0/user.Content-Type |
| 21 | * .. or similar. |
| 22 | * |
| 23 | * The file contents are the text of the EA. The size is known based on the |
| 24 | * stat data describing the file. |
| 25 | * |
| 26 | * In the case of system.posix_acl_access and system.posix_acl_default, since |
| 27 | * these are special cases for filesystem ACLs, they are interpreted by the |
| 28 | * kernel, in addition, they are negatively and positively cached and attached |
| 29 | * to the inode so that unnecessary lookups are avoided. |
| 30 | * |
| 31 | * Locking works like so: |
| 32 | * Directory components (xattr root, xattr dir) are protectd by their i_mutex. |
| 33 | * The xattrs themselves are protected by the xattr_sem. |
| 34 | */ |
| 35 | |
| 36 | #include "reiserfs.h" |
| 37 | #include <linux/capability.h> |
| 38 | #include <linux/dcache.h> |
| 39 | #include <linux/namei.h> |
| 40 | #include <linux/errno.h> |
| 41 | #include <linux/gfp.h> |
| 42 | #include <linux/fs.h> |
| 43 | #include <linux/file.h> |
| 44 | #include <linux/pagemap.h> |
| 45 | #include <linux/xattr.h> |
| 46 | #include "xattr.h" |
| 47 | #include "acl.h" |
| 48 | #include <linux/uaccess.h> |
| 49 | #include <net/checksum.h> |
| 50 | #include <linux/stat.h> |
| 51 | #include <linux/quotaops.h> |
| 52 | #include <linux/security.h> |
| 53 | #include <linux/posix_acl_xattr.h> |
| 54 | |
| 55 | #define PRIVROOT_NAME ".reiserfs_priv" |
| 56 | #define XAROOT_NAME "xattrs" |
| 57 | |
| 58 | |
| 59 | /* |
| 60 | * Helpers for inode ops. We do this so that we don't have all the VFS |
| 61 | * overhead and also for proper i_mutex annotation. |
| 62 | * dir->i_mutex must be held for all of them. |
| 63 | */ |
| 64 | #ifdef CONFIG_REISERFS_FS_XATTR |
| 65 | static int xattr_create(struct inode *dir, struct dentry *dentry, int mode) |
| 66 | { |
| 67 | BUG_ON(!inode_is_locked(dir)); |
| 68 | return dir->i_op->create(dir, dentry, mode, true); |
| 69 | } |
| 70 | #endif |
| 71 | |
| 72 | static int xattr_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) |
| 73 | { |
| 74 | BUG_ON(!inode_is_locked(dir)); |
| 75 | return dir->i_op->mkdir(dir, dentry, mode); |
| 76 | } |
| 77 | |
| 78 | /* |
| 79 | * We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr |
| 80 | * mutation ops aren't called during rename or splace, which are the |
| 81 | * only other users of I_MUTEX_CHILD. It violates the ordering, but that's |
| 82 | * better than allocating another subclass just for this code. |
| 83 | */ |
| 84 | static int xattr_unlink(struct inode *dir, struct dentry *dentry) |
| 85 | { |
| 86 | int error; |
| 87 | |
| 88 | BUG_ON(!inode_is_locked(dir)); |
| 89 | |
| 90 | inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); |
| 91 | error = dir->i_op->unlink(dir, dentry); |
| 92 | inode_unlock(d_inode(dentry)); |
| 93 | |
| 94 | if (!error) |
| 95 | d_delete(dentry); |
| 96 | return error; |
| 97 | } |
| 98 | |
| 99 | static int xattr_rmdir(struct inode *dir, struct dentry *dentry) |
| 100 | { |
| 101 | int error; |
| 102 | |
| 103 | BUG_ON(!inode_is_locked(dir)); |
| 104 | |
| 105 | inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD); |
| 106 | error = dir->i_op->rmdir(dir, dentry); |
| 107 | if (!error) |
| 108 | d_inode(dentry)->i_flags |= S_DEAD; |
| 109 | inode_unlock(d_inode(dentry)); |
| 110 | if (!error) |
| 111 | d_delete(dentry); |
| 112 | |
| 113 | return error; |
| 114 | } |
| 115 | |
| 116 | #define xattr_may_create(flags) (!flags || flags & XATTR_CREATE) |
| 117 | |
| 118 | static struct dentry *open_xa_root(struct super_block *sb, int flags) |
| 119 | { |
| 120 | struct dentry *privroot = REISERFS_SB(sb)->priv_root; |
| 121 | struct dentry *xaroot; |
| 122 | |
| 123 | if (d_really_is_negative(privroot)) |
| 124 | return ERR_PTR(-ENODATA); |
| 125 | |
| 126 | inode_lock_nested(d_inode(privroot), I_MUTEX_XATTR); |
| 127 | |
| 128 | xaroot = dget(REISERFS_SB(sb)->xattr_root); |
| 129 | if (!xaroot) |
| 130 | xaroot = ERR_PTR(-ENODATA); |
| 131 | else if (d_really_is_negative(xaroot)) { |
| 132 | int err = -ENODATA; |
| 133 | |
| 134 | if (xattr_may_create(flags)) |
| 135 | err = xattr_mkdir(d_inode(privroot), xaroot, 0700); |
| 136 | if (err) { |
| 137 | dput(xaroot); |
| 138 | xaroot = ERR_PTR(err); |
| 139 | } |
| 140 | } |
| 141 | |
| 142 | inode_unlock(d_inode(privroot)); |
| 143 | return xaroot; |
| 144 | } |
| 145 | |
| 146 | static struct dentry *open_xa_dir(const struct inode *inode, int flags) |
| 147 | { |
| 148 | struct dentry *xaroot, *xadir; |
| 149 | char namebuf[17]; |
| 150 | |
| 151 | xaroot = open_xa_root(inode->i_sb, flags); |
| 152 | if (IS_ERR(xaroot)) |
| 153 | return xaroot; |
| 154 | |
| 155 | snprintf(namebuf, sizeof(namebuf), "%X.%X", |
| 156 | le32_to_cpu(INODE_PKEY(inode)->k_objectid), |
| 157 | inode->i_generation); |
| 158 | |
| 159 | inode_lock_nested(d_inode(xaroot), I_MUTEX_XATTR); |
| 160 | |
| 161 | xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf)); |
| 162 | if (!IS_ERR(xadir) && d_really_is_negative(xadir)) { |
| 163 | int err = -ENODATA; |
| 164 | |
| 165 | if (xattr_may_create(flags)) |
| 166 | err = xattr_mkdir(d_inode(xaroot), xadir, 0700); |
| 167 | if (err) { |
| 168 | dput(xadir); |
| 169 | xadir = ERR_PTR(err); |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | inode_unlock(d_inode(xaroot)); |
| 174 | dput(xaroot); |
| 175 | return xadir; |
| 176 | } |
| 177 | |
| 178 | /* |
| 179 | * The following are side effects of other operations that aren't explicitly |
| 180 | * modifying extended attributes. This includes operations such as permissions |
| 181 | * or ownership changes, object deletions, etc. |
| 182 | */ |
| 183 | struct reiserfs_dentry_buf { |
| 184 | struct dir_context ctx; |
| 185 | struct dentry *xadir; |
| 186 | int count; |
| 187 | struct dentry *dentries[8]; |
| 188 | }; |
| 189 | |
| 190 | static int |
| 191 | fill_with_dentries(struct dir_context *ctx, const char *name, int namelen, |
| 192 | loff_t offset, u64 ino, unsigned int d_type) |
| 193 | { |
| 194 | struct reiserfs_dentry_buf *dbuf = |
| 195 | container_of(ctx, struct reiserfs_dentry_buf, ctx); |
| 196 | struct dentry *dentry; |
| 197 | |
| 198 | WARN_ON_ONCE(!inode_is_locked(d_inode(dbuf->xadir))); |
| 199 | |
| 200 | if (dbuf->count == ARRAY_SIZE(dbuf->dentries)) |
| 201 | return -ENOSPC; |
| 202 | |
| 203 | if (name[0] == '.' && (namelen < 2 || |
| 204 | (namelen == 2 && name[1] == '.'))) |
| 205 | return 0; |
| 206 | |
| 207 | dentry = lookup_one_len(name, dbuf->xadir, namelen); |
| 208 | if (IS_ERR(dentry)) { |
| 209 | return PTR_ERR(dentry); |
| 210 | } else if (d_really_is_negative(dentry)) { |
| 211 | /* A directory entry exists, but no file? */ |
| 212 | reiserfs_error(dentry->d_sb, "xattr-20003", |
| 213 | "Corrupted directory: xattr %pd listed but " |
| 214 | "not found for file %pd.\n", |
| 215 | dentry, dbuf->xadir); |
| 216 | dput(dentry); |
| 217 | return -EIO; |
| 218 | } |
| 219 | |
| 220 | dbuf->dentries[dbuf->count++] = dentry; |
| 221 | return 0; |
| 222 | } |
| 223 | |
| 224 | static void |
| 225 | cleanup_dentry_buf(struct reiserfs_dentry_buf *buf) |
| 226 | { |
| 227 | int i; |
| 228 | |
| 229 | for (i = 0; i < buf->count; i++) |
| 230 | if (buf->dentries[i]) |
| 231 | dput(buf->dentries[i]); |
| 232 | } |
| 233 | |
| 234 | static int reiserfs_for_each_xattr(struct inode *inode, |
| 235 | int (*action)(struct dentry *, void *), |
| 236 | void *data) |
| 237 | { |
| 238 | struct dentry *dir; |
| 239 | int i, err = 0; |
| 240 | struct reiserfs_dentry_buf buf = { |
| 241 | .ctx.actor = fill_with_dentries, |
| 242 | }; |
| 243 | |
| 244 | /* Skip out, an xattr has no xattrs associated with it */ |
| 245 | if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1) |
| 246 | return 0; |
| 247 | |
| 248 | dir = open_xa_dir(inode, XATTR_REPLACE); |
| 249 | if (IS_ERR(dir)) { |
| 250 | err = PTR_ERR(dir); |
| 251 | goto out; |
| 252 | } else if (d_really_is_negative(dir)) { |
| 253 | err = 0; |
| 254 | goto out_dir; |
| 255 | } |
| 256 | |
| 257 | inode_lock_nested(d_inode(dir), I_MUTEX_XATTR); |
| 258 | |
| 259 | buf.xadir = dir; |
| 260 | while (1) { |
| 261 | err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx); |
| 262 | if (err) |
| 263 | break; |
| 264 | if (!buf.count) |
| 265 | break; |
| 266 | for (i = 0; !err && i < buf.count && buf.dentries[i]; i++) { |
| 267 | struct dentry *dentry = buf.dentries[i]; |
| 268 | |
| 269 | if (!d_is_dir(dentry)) |
| 270 | err = action(dentry, data); |
| 271 | |
| 272 | dput(dentry); |
| 273 | buf.dentries[i] = NULL; |
| 274 | } |
| 275 | if (err) |
| 276 | break; |
| 277 | buf.count = 0; |
| 278 | } |
| 279 | inode_unlock(d_inode(dir)); |
| 280 | |
| 281 | cleanup_dentry_buf(&buf); |
| 282 | |
| 283 | if (!err) { |
| 284 | /* |
| 285 | * We start a transaction here to avoid a ABBA situation |
| 286 | * between the xattr root's i_mutex and the journal lock. |
| 287 | * This doesn't incur much additional overhead since the |
| 288 | * new transaction will just nest inside the |
| 289 | * outer transaction. |
| 290 | */ |
| 291 | int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 + |
| 292 | 4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb); |
| 293 | struct reiserfs_transaction_handle th; |
| 294 | |
| 295 | reiserfs_write_lock(inode->i_sb); |
| 296 | err = journal_begin(&th, inode->i_sb, blocks); |
| 297 | reiserfs_write_unlock(inode->i_sb); |
| 298 | if (!err) { |
| 299 | int jerror; |
| 300 | |
| 301 | inode_lock_nested(d_inode(dir->d_parent), |
| 302 | I_MUTEX_XATTR); |
| 303 | err = action(dir, data); |
| 304 | reiserfs_write_lock(inode->i_sb); |
| 305 | jerror = journal_end(&th); |
| 306 | reiserfs_write_unlock(inode->i_sb); |
| 307 | inode_unlock(d_inode(dir->d_parent)); |
| 308 | err = jerror ?: err; |
| 309 | } |
| 310 | } |
| 311 | out_dir: |
| 312 | dput(dir); |
| 313 | out: |
| 314 | /* -ENODATA isn't an error */ |
| 315 | if (err == -ENODATA) |
| 316 | err = 0; |
| 317 | return err; |
| 318 | } |
| 319 | |
| 320 | static int delete_one_xattr(struct dentry *dentry, void *data) |
| 321 | { |
| 322 | struct inode *dir = d_inode(dentry->d_parent); |
| 323 | |
| 324 | /* This is the xattr dir, handle specially. */ |
| 325 | if (d_is_dir(dentry)) |
| 326 | return xattr_rmdir(dir, dentry); |
| 327 | |
| 328 | return xattr_unlink(dir, dentry); |
| 329 | } |
| 330 | |
| 331 | static int chown_one_xattr(struct dentry *dentry, void *data) |
| 332 | { |
| 333 | struct iattr *attrs = data; |
| 334 | int ia_valid = attrs->ia_valid; |
| 335 | int err; |
| 336 | |
| 337 | /* |
| 338 | * We only want the ownership bits. Otherwise, we'll do |
| 339 | * things like change a directory to a regular file if |
| 340 | * ATTR_MODE is set. |
| 341 | */ |
| 342 | attrs->ia_valid &= (ATTR_UID|ATTR_GID); |
| 343 | err = reiserfs_setattr(dentry, attrs); |
| 344 | attrs->ia_valid = ia_valid; |
| 345 | |
| 346 | return err; |
| 347 | } |
| 348 | |
| 349 | /* No i_mutex, but the inode is unconnected. */ |
| 350 | int reiserfs_delete_xattrs(struct inode *inode) |
| 351 | { |
| 352 | int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL); |
| 353 | |
| 354 | if (err) |
| 355 | reiserfs_warning(inode->i_sb, "jdm-20004", |
| 356 | "Couldn't delete all xattrs (%d)\n", err); |
| 357 | return err; |
| 358 | } |
| 359 | |
| 360 | /* inode->i_mutex: down */ |
| 361 | int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) |
| 362 | { |
| 363 | int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs); |
| 364 | |
| 365 | if (err) |
| 366 | reiserfs_warning(inode->i_sb, "jdm-20007", |
| 367 | "Couldn't chown all xattrs (%d)\n", err); |
| 368 | return err; |
| 369 | } |
| 370 | |
| 371 | #ifdef CONFIG_REISERFS_FS_XATTR |
| 372 | /* |
| 373 | * Returns a dentry corresponding to a specific extended attribute file |
| 374 | * for the inode. If flags allow, the file is created. Otherwise, a |
| 375 | * valid or negative dentry, or an error is returned. |
| 376 | */ |
| 377 | static struct dentry *xattr_lookup(struct inode *inode, const char *name, |
| 378 | int flags) |
| 379 | { |
| 380 | struct dentry *xadir, *xafile; |
| 381 | int err = 0; |
| 382 | |
| 383 | xadir = open_xa_dir(inode, flags); |
| 384 | if (IS_ERR(xadir)) |
| 385 | return ERR_CAST(xadir); |
| 386 | |
| 387 | inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR); |
| 388 | xafile = lookup_one_len(name, xadir, strlen(name)); |
| 389 | if (IS_ERR(xafile)) { |
| 390 | err = PTR_ERR(xafile); |
| 391 | goto out; |
| 392 | } |
| 393 | |
| 394 | if (d_really_is_positive(xafile) && (flags & XATTR_CREATE)) |
| 395 | err = -EEXIST; |
| 396 | |
| 397 | if (d_really_is_negative(xafile)) { |
| 398 | err = -ENODATA; |
| 399 | if (xattr_may_create(flags)) |
| 400 | err = xattr_create(d_inode(xadir), xafile, |
| 401 | 0700|S_IFREG); |
| 402 | } |
| 403 | |
| 404 | if (err) |
| 405 | dput(xafile); |
| 406 | out: |
| 407 | inode_unlock(d_inode(xadir)); |
| 408 | dput(xadir); |
| 409 | if (err) |
| 410 | return ERR_PTR(err); |
| 411 | return xafile; |
| 412 | } |
| 413 | |
| 414 | /* Internal operations on file data */ |
| 415 | static inline void reiserfs_put_page(struct page *page) |
| 416 | { |
| 417 | kunmap(page); |
| 418 | page_cache_release(page); |
| 419 | } |
| 420 | |
| 421 | static struct page *reiserfs_get_page(struct inode *dir, size_t n) |
| 422 | { |
| 423 | struct address_space *mapping = dir->i_mapping; |
| 424 | struct page *page; |
| 425 | /* |
| 426 | * We can deadlock if we try to free dentries, |
| 427 | * and an unlink/rmdir has just occurred - GFP_NOFS avoids this |
| 428 | */ |
| 429 | mapping_set_gfp_mask(mapping, GFP_NOFS); |
| 430 | page = read_mapping_page(mapping, n >> PAGE_CACHE_SHIFT, NULL); |
| 431 | if (!IS_ERR(page)) { |
| 432 | kmap(page); |
| 433 | if (PageError(page)) |
| 434 | goto fail; |
| 435 | } |
| 436 | return page; |
| 437 | |
| 438 | fail: |
| 439 | reiserfs_put_page(page); |
| 440 | return ERR_PTR(-EIO); |
| 441 | } |
| 442 | |
| 443 | static inline __u32 xattr_hash(const char *msg, int len) |
| 444 | { |
| 445 | return csum_partial(msg, len, 0); |
| 446 | } |
| 447 | |
| 448 | int reiserfs_commit_write(struct file *f, struct page *page, |
| 449 | unsigned from, unsigned to); |
| 450 | |
| 451 | static void update_ctime(struct inode *inode) |
| 452 | { |
| 453 | struct timespec now = current_fs_time(inode->i_sb); |
| 454 | |
| 455 | if (inode_unhashed(inode) || !inode->i_nlink || |
| 456 | timespec_equal(&inode->i_ctime, &now)) |
| 457 | return; |
| 458 | |
| 459 | inode->i_ctime = CURRENT_TIME_SEC; |
| 460 | mark_inode_dirty(inode); |
| 461 | } |
| 462 | |
| 463 | static int lookup_and_delete_xattr(struct inode *inode, const char *name) |
| 464 | { |
| 465 | int err = 0; |
| 466 | struct dentry *dentry, *xadir; |
| 467 | |
| 468 | xadir = open_xa_dir(inode, XATTR_REPLACE); |
| 469 | if (IS_ERR(xadir)) |
| 470 | return PTR_ERR(xadir); |
| 471 | |
| 472 | inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR); |
| 473 | dentry = lookup_one_len(name, xadir, strlen(name)); |
| 474 | if (IS_ERR(dentry)) { |
| 475 | err = PTR_ERR(dentry); |
| 476 | goto out_dput; |
| 477 | } |
| 478 | |
| 479 | if (d_really_is_positive(dentry)) { |
| 480 | err = xattr_unlink(d_inode(xadir), dentry); |
| 481 | update_ctime(inode); |
| 482 | } |
| 483 | |
| 484 | dput(dentry); |
| 485 | out_dput: |
| 486 | inode_unlock(d_inode(xadir)); |
| 487 | dput(xadir); |
| 488 | return err; |
| 489 | } |
| 490 | |
| 491 | |
| 492 | /* Generic extended attribute operations that can be used by xa plugins */ |
| 493 | |
| 494 | /* |
| 495 | * inode->i_mutex: down |
| 496 | */ |
| 497 | int |
| 498 | reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th, |
| 499 | struct inode *inode, const char *name, |
| 500 | const void *buffer, size_t buffer_size, int flags) |
| 501 | { |
| 502 | int err = 0; |
| 503 | struct dentry *dentry; |
| 504 | struct page *page; |
| 505 | char *data; |
| 506 | size_t file_pos = 0; |
| 507 | size_t buffer_pos = 0; |
| 508 | size_t new_size; |
| 509 | __u32 xahash = 0; |
| 510 | |
| 511 | if (get_inode_sd_version(inode) == STAT_DATA_V1) |
| 512 | return -EOPNOTSUPP; |
| 513 | |
| 514 | if (!buffer) { |
| 515 | err = lookup_and_delete_xattr(inode, name); |
| 516 | return err; |
| 517 | } |
| 518 | |
| 519 | dentry = xattr_lookup(inode, name, flags); |
| 520 | if (IS_ERR(dentry)) |
| 521 | return PTR_ERR(dentry); |
| 522 | |
| 523 | down_write(&REISERFS_I(inode)->i_xattr_sem); |
| 524 | |
| 525 | xahash = xattr_hash(buffer, buffer_size); |
| 526 | while (buffer_pos < buffer_size || buffer_pos == 0) { |
| 527 | size_t chunk; |
| 528 | size_t skip = 0; |
| 529 | size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); |
| 530 | |
| 531 | if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) |
| 532 | chunk = PAGE_CACHE_SIZE; |
| 533 | else |
| 534 | chunk = buffer_size - buffer_pos; |
| 535 | |
| 536 | page = reiserfs_get_page(d_inode(dentry), file_pos); |
| 537 | if (IS_ERR(page)) { |
| 538 | err = PTR_ERR(page); |
| 539 | goto out_unlock; |
| 540 | } |
| 541 | |
| 542 | lock_page(page); |
| 543 | data = page_address(page); |
| 544 | |
| 545 | if (file_pos == 0) { |
| 546 | struct reiserfs_xattr_header *rxh; |
| 547 | |
| 548 | skip = file_pos = sizeof(struct reiserfs_xattr_header); |
| 549 | if (chunk + skip > PAGE_CACHE_SIZE) |
| 550 | chunk = PAGE_CACHE_SIZE - skip; |
| 551 | rxh = (struct reiserfs_xattr_header *)data; |
| 552 | rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); |
| 553 | rxh->h_hash = cpu_to_le32(xahash); |
| 554 | } |
| 555 | |
| 556 | reiserfs_write_lock(inode->i_sb); |
| 557 | err = __reiserfs_write_begin(page, page_offset, chunk + skip); |
| 558 | if (!err) { |
| 559 | if (buffer) |
| 560 | memcpy(data + skip, buffer + buffer_pos, chunk); |
| 561 | err = reiserfs_commit_write(NULL, page, page_offset, |
| 562 | page_offset + chunk + |
| 563 | skip); |
| 564 | } |
| 565 | reiserfs_write_unlock(inode->i_sb); |
| 566 | unlock_page(page); |
| 567 | reiserfs_put_page(page); |
| 568 | buffer_pos += chunk; |
| 569 | file_pos += chunk; |
| 570 | skip = 0; |
| 571 | if (err || buffer_size == 0 || !buffer) |
| 572 | break; |
| 573 | } |
| 574 | |
| 575 | new_size = buffer_size + sizeof(struct reiserfs_xattr_header); |
| 576 | if (!err && new_size < i_size_read(d_inode(dentry))) { |
| 577 | struct iattr newattrs = { |
| 578 | .ia_ctime = current_fs_time(inode->i_sb), |
| 579 | .ia_size = new_size, |
| 580 | .ia_valid = ATTR_SIZE | ATTR_CTIME, |
| 581 | }; |
| 582 | |
| 583 | inode_lock_nested(d_inode(dentry), I_MUTEX_XATTR); |
| 584 | inode_dio_wait(d_inode(dentry)); |
| 585 | |
| 586 | err = reiserfs_setattr(dentry, &newattrs); |
| 587 | inode_unlock(d_inode(dentry)); |
| 588 | } else |
| 589 | update_ctime(inode); |
| 590 | out_unlock: |
| 591 | up_write(&REISERFS_I(inode)->i_xattr_sem); |
| 592 | dput(dentry); |
| 593 | return err; |
| 594 | } |
| 595 | |
| 596 | /* We need to start a transaction to maintain lock ordering */ |
| 597 | int reiserfs_xattr_set(struct inode *inode, const char *name, |
| 598 | const void *buffer, size_t buffer_size, int flags) |
| 599 | { |
| 600 | |
| 601 | struct reiserfs_transaction_handle th; |
| 602 | int error, error2; |
| 603 | size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size); |
| 604 | |
| 605 | if (!(flags & XATTR_REPLACE)) |
| 606 | jbegin_count += reiserfs_xattr_jcreate_nblocks(inode); |
| 607 | |
| 608 | reiserfs_write_lock(inode->i_sb); |
| 609 | error = journal_begin(&th, inode->i_sb, jbegin_count); |
| 610 | reiserfs_write_unlock(inode->i_sb); |
| 611 | if (error) { |
| 612 | return error; |
| 613 | } |
| 614 | |
| 615 | error = reiserfs_xattr_set_handle(&th, inode, name, |
| 616 | buffer, buffer_size, flags); |
| 617 | |
| 618 | reiserfs_write_lock(inode->i_sb); |
| 619 | error2 = journal_end(&th); |
| 620 | reiserfs_write_unlock(inode->i_sb); |
| 621 | if (error == 0) |
| 622 | error = error2; |
| 623 | |
| 624 | return error; |
| 625 | } |
| 626 | |
| 627 | /* |
| 628 | * inode->i_mutex: down |
| 629 | */ |
| 630 | int |
| 631 | reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer, |
| 632 | size_t buffer_size) |
| 633 | { |
| 634 | ssize_t err = 0; |
| 635 | struct dentry *dentry; |
| 636 | size_t isize; |
| 637 | size_t file_pos = 0; |
| 638 | size_t buffer_pos = 0; |
| 639 | struct page *page; |
| 640 | __u32 hash = 0; |
| 641 | |
| 642 | if (name == NULL) |
| 643 | return -EINVAL; |
| 644 | |
| 645 | /* |
| 646 | * We can't have xattrs attached to v1 items since they don't have |
| 647 | * generation numbers |
| 648 | */ |
| 649 | if (get_inode_sd_version(inode) == STAT_DATA_V1) |
| 650 | return -EOPNOTSUPP; |
| 651 | |
| 652 | dentry = xattr_lookup(inode, name, XATTR_REPLACE); |
| 653 | if (IS_ERR(dentry)) { |
| 654 | err = PTR_ERR(dentry); |
| 655 | goto out; |
| 656 | } |
| 657 | |
| 658 | down_read(&REISERFS_I(inode)->i_xattr_sem); |
| 659 | |
| 660 | isize = i_size_read(d_inode(dentry)); |
| 661 | |
| 662 | /* Just return the size needed */ |
| 663 | if (buffer == NULL) { |
| 664 | err = isize - sizeof(struct reiserfs_xattr_header); |
| 665 | goto out_unlock; |
| 666 | } |
| 667 | |
| 668 | if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { |
| 669 | err = -ERANGE; |
| 670 | goto out_unlock; |
| 671 | } |
| 672 | |
| 673 | while (file_pos < isize) { |
| 674 | size_t chunk; |
| 675 | char *data; |
| 676 | size_t skip = 0; |
| 677 | |
| 678 | if (isize - file_pos > PAGE_CACHE_SIZE) |
| 679 | chunk = PAGE_CACHE_SIZE; |
| 680 | else |
| 681 | chunk = isize - file_pos; |
| 682 | |
| 683 | page = reiserfs_get_page(d_inode(dentry), file_pos); |
| 684 | if (IS_ERR(page)) { |
| 685 | err = PTR_ERR(page); |
| 686 | goto out_unlock; |
| 687 | } |
| 688 | |
| 689 | lock_page(page); |
| 690 | data = page_address(page); |
| 691 | if (file_pos == 0) { |
| 692 | struct reiserfs_xattr_header *rxh = |
| 693 | (struct reiserfs_xattr_header *)data; |
| 694 | skip = file_pos = sizeof(struct reiserfs_xattr_header); |
| 695 | chunk -= skip; |
| 696 | /* Magic doesn't match up.. */ |
| 697 | if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { |
| 698 | unlock_page(page); |
| 699 | reiserfs_put_page(page); |
| 700 | reiserfs_warning(inode->i_sb, "jdm-20001", |
| 701 | "Invalid magic for xattr (%s) " |
| 702 | "associated with %k", name, |
| 703 | INODE_PKEY(inode)); |
| 704 | err = -EIO; |
| 705 | goto out_unlock; |
| 706 | } |
| 707 | hash = le32_to_cpu(rxh->h_hash); |
| 708 | } |
| 709 | memcpy(buffer + buffer_pos, data + skip, chunk); |
| 710 | unlock_page(page); |
| 711 | reiserfs_put_page(page); |
| 712 | file_pos += chunk; |
| 713 | buffer_pos += chunk; |
| 714 | skip = 0; |
| 715 | } |
| 716 | err = isize - sizeof(struct reiserfs_xattr_header); |
| 717 | |
| 718 | if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != |
| 719 | hash) { |
| 720 | reiserfs_warning(inode->i_sb, "jdm-20002", |
| 721 | "Invalid hash for xattr (%s) associated " |
| 722 | "with %k", name, INODE_PKEY(inode)); |
| 723 | err = -EIO; |
| 724 | } |
| 725 | |
| 726 | out_unlock: |
| 727 | up_read(&REISERFS_I(inode)->i_xattr_sem); |
| 728 | dput(dentry); |
| 729 | |
| 730 | out: |
| 731 | return err; |
| 732 | } |
| 733 | |
| 734 | /* |
| 735 | * In order to implement different sets of xattr operations for each xattr |
| 736 | * prefix with the generic xattr API, a filesystem should create a |
| 737 | * null-terminated array of struct xattr_handler (one for each prefix) and |
| 738 | * hang a pointer to it off of the s_xattr field of the superblock. |
| 739 | * |
| 740 | * The generic_fooxattr() functions will use this list to dispatch xattr |
| 741 | * operations to the correct xattr_handler. |
| 742 | */ |
| 743 | #define for_each_xattr_handler(handlers, handler) \ |
| 744 | for ((handler) = *(handlers)++; \ |
| 745 | (handler) != NULL; \ |
| 746 | (handler) = *(handlers)++) |
| 747 | |
| 748 | /* This is the implementation for the xattr plugin infrastructure */ |
| 749 | static inline const struct xattr_handler * |
| 750 | find_xattr_handler_prefix(const struct xattr_handler **handlers, |
| 751 | const char *name) |
| 752 | { |
| 753 | const struct xattr_handler *xah; |
| 754 | |
| 755 | if (!handlers) |
| 756 | return NULL; |
| 757 | |
| 758 | for_each_xattr_handler(handlers, xah) { |
| 759 | const char *prefix = xattr_prefix(xah); |
| 760 | if (strncmp(prefix, name, strlen(prefix)) == 0) |
| 761 | break; |
| 762 | } |
| 763 | |
| 764 | return xah; |
| 765 | } |
| 766 | |
| 767 | |
| 768 | /* |
| 769 | * Inode operation getxattr() |
| 770 | */ |
| 771 | ssize_t |
| 772 | reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, |
| 773 | size_t size) |
| 774 | { |
| 775 | const struct xattr_handler *handler; |
| 776 | |
| 777 | handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); |
| 778 | |
| 779 | if (!handler || get_inode_sd_version(d_inode(dentry)) == STAT_DATA_V1) |
| 780 | return -EOPNOTSUPP; |
| 781 | |
| 782 | return handler->get(handler, dentry, name, buffer, size); |
| 783 | } |
| 784 | |
| 785 | /* |
| 786 | * Inode operation setxattr() |
| 787 | * |
| 788 | * d_inode(dentry)->i_mutex down |
| 789 | */ |
| 790 | int |
| 791 | reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, |
| 792 | size_t size, int flags) |
| 793 | { |
| 794 | const struct xattr_handler *handler; |
| 795 | |
| 796 | handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); |
| 797 | |
| 798 | if (!handler || get_inode_sd_version(d_inode(dentry)) == STAT_DATA_V1) |
| 799 | return -EOPNOTSUPP; |
| 800 | |
| 801 | return handler->set(handler, dentry, name, value, size, flags); |
| 802 | } |
| 803 | |
| 804 | /* |
| 805 | * Inode operation removexattr() |
| 806 | * |
| 807 | * d_inode(dentry)->i_mutex down |
| 808 | */ |
| 809 | int reiserfs_removexattr(struct dentry *dentry, const char *name) |
| 810 | { |
| 811 | const struct xattr_handler *handler; |
| 812 | |
| 813 | handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); |
| 814 | |
| 815 | if (!handler || get_inode_sd_version(d_inode(dentry)) == STAT_DATA_V1) |
| 816 | return -EOPNOTSUPP; |
| 817 | |
| 818 | return handler->set(handler, dentry, name, NULL, 0, XATTR_REPLACE); |
| 819 | } |
| 820 | |
| 821 | struct listxattr_buf { |
| 822 | struct dir_context ctx; |
| 823 | size_t size; |
| 824 | size_t pos; |
| 825 | char *buf; |
| 826 | struct dentry *dentry; |
| 827 | }; |
| 828 | |
| 829 | static int listxattr_filler(struct dir_context *ctx, const char *name, |
| 830 | int namelen, loff_t offset, u64 ino, |
| 831 | unsigned int d_type) |
| 832 | { |
| 833 | struct listxattr_buf *b = |
| 834 | container_of(ctx, struct listxattr_buf, ctx); |
| 835 | size_t size; |
| 836 | |
| 837 | if (name[0] != '.' || |
| 838 | (namelen != 1 && (name[1] != '.' || namelen != 2))) { |
| 839 | const struct xattr_handler *handler; |
| 840 | |
| 841 | handler = find_xattr_handler_prefix(b->dentry->d_sb->s_xattr, |
| 842 | name); |
| 843 | if (!handler /* Unsupported xattr name */ || |
| 844 | (handler->list && !handler->list(b->dentry))) |
| 845 | return 0; |
| 846 | size = namelen + 1; |
| 847 | if (b->buf) { |
| 848 | if (size > b->size) |
| 849 | return -ERANGE; |
| 850 | memcpy(b->buf + b->pos, name, namelen); |
| 851 | b->buf[b->pos + namelen] = 0; |
| 852 | } |
| 853 | b->pos += size; |
| 854 | } |
| 855 | return 0; |
| 856 | } |
| 857 | |
| 858 | /* |
| 859 | * Inode operation listxattr() |
| 860 | * |
| 861 | * We totally ignore the generic listxattr here because it would be stupid |
| 862 | * not to. Since the xattrs are organized in a directory, we can just |
| 863 | * readdir to find them. |
| 864 | */ |
| 865 | ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) |
| 866 | { |
| 867 | struct dentry *dir; |
| 868 | int err = 0; |
| 869 | struct listxattr_buf buf = { |
| 870 | .ctx.actor = listxattr_filler, |
| 871 | .dentry = dentry, |
| 872 | .buf = buffer, |
| 873 | .size = buffer ? size : 0, |
| 874 | }; |
| 875 | |
| 876 | if (d_really_is_negative(dentry)) |
| 877 | return -EINVAL; |
| 878 | |
| 879 | if (!dentry->d_sb->s_xattr || |
| 880 | get_inode_sd_version(d_inode(dentry)) == STAT_DATA_V1) |
| 881 | return -EOPNOTSUPP; |
| 882 | |
| 883 | dir = open_xa_dir(d_inode(dentry), XATTR_REPLACE); |
| 884 | if (IS_ERR(dir)) { |
| 885 | err = PTR_ERR(dir); |
| 886 | if (err == -ENODATA) |
| 887 | err = 0; /* Not an error if there aren't any xattrs */ |
| 888 | goto out; |
| 889 | } |
| 890 | |
| 891 | inode_lock_nested(d_inode(dir), I_MUTEX_XATTR); |
| 892 | err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx); |
| 893 | inode_unlock(d_inode(dir)); |
| 894 | |
| 895 | if (!err) |
| 896 | err = buf.pos; |
| 897 | |
| 898 | dput(dir); |
| 899 | out: |
| 900 | return err; |
| 901 | } |
| 902 | |
| 903 | static int create_privroot(struct dentry *dentry) |
| 904 | { |
| 905 | int err; |
| 906 | struct inode *inode = d_inode(dentry->d_parent); |
| 907 | |
| 908 | WARN_ON_ONCE(!inode_is_locked(inode)); |
| 909 | |
| 910 | err = xattr_mkdir(inode, dentry, 0700); |
| 911 | if (err || d_really_is_negative(dentry)) { |
| 912 | reiserfs_warning(dentry->d_sb, "jdm-20006", |
| 913 | "xattrs/ACLs enabled and couldn't " |
| 914 | "find/create .reiserfs_priv. " |
| 915 | "Failing mount."); |
| 916 | return -EOPNOTSUPP; |
| 917 | } |
| 918 | |
| 919 | d_inode(dentry)->i_flags |= S_PRIVATE; |
| 920 | reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr " |
| 921 | "storage.\n", PRIVROOT_NAME); |
| 922 | |
| 923 | return 0; |
| 924 | } |
| 925 | |
| 926 | #else |
| 927 | int __init reiserfs_xattr_register_handlers(void) { return 0; } |
| 928 | void reiserfs_xattr_unregister_handlers(void) {} |
| 929 | static int create_privroot(struct dentry *dentry) { return 0; } |
| 930 | #endif |
| 931 | |
| 932 | /* Actual operations that are exported to VFS-land */ |
| 933 | static const struct xattr_handler *reiserfs_xattr_handlers[] = { |
| 934 | #ifdef CONFIG_REISERFS_FS_XATTR |
| 935 | &reiserfs_xattr_user_handler, |
| 936 | &reiserfs_xattr_trusted_handler, |
| 937 | #endif |
| 938 | #ifdef CONFIG_REISERFS_FS_SECURITY |
| 939 | &reiserfs_xattr_security_handler, |
| 940 | #endif |
| 941 | #ifdef CONFIG_REISERFS_FS_POSIX_ACL |
| 942 | &posix_acl_access_xattr_handler, |
| 943 | &posix_acl_default_xattr_handler, |
| 944 | #endif |
| 945 | NULL |
| 946 | }; |
| 947 | |
| 948 | static int xattr_mount_check(struct super_block *s) |
| 949 | { |
| 950 | /* |
| 951 | * We need generation numbers to ensure that the oid mapping is correct |
| 952 | * v3.5 filesystems don't have them. |
| 953 | */ |
| 954 | if (old_format_only(s)) { |
| 955 | if (reiserfs_xattrs_optional(s)) { |
| 956 | /* |
| 957 | * Old format filesystem, but optional xattrs have |
| 958 | * been enabled. Error out. |
| 959 | */ |
| 960 | reiserfs_warning(s, "jdm-2005", |
| 961 | "xattrs/ACLs not supported " |
| 962 | "on pre-v3.6 format filesystems. " |
| 963 | "Failing mount."); |
| 964 | return -EOPNOTSUPP; |
| 965 | } |
| 966 | } |
| 967 | |
| 968 | return 0; |
| 969 | } |
| 970 | |
| 971 | int reiserfs_permission(struct inode *inode, int mask) |
| 972 | { |
| 973 | /* |
| 974 | * We don't do permission checks on the internal objects. |
| 975 | * Permissions are determined by the "owning" object. |
| 976 | */ |
| 977 | if (IS_PRIVATE(inode)) |
| 978 | return 0; |
| 979 | |
| 980 | return generic_permission(inode, mask); |
| 981 | } |
| 982 | |
| 983 | static int xattr_hide_revalidate(struct dentry *dentry, unsigned int flags) |
| 984 | { |
| 985 | return -EPERM; |
| 986 | } |
| 987 | |
| 988 | static const struct dentry_operations xattr_lookup_poison_ops = { |
| 989 | .d_revalidate = xattr_hide_revalidate, |
| 990 | }; |
| 991 | |
| 992 | int reiserfs_lookup_privroot(struct super_block *s) |
| 993 | { |
| 994 | struct dentry *dentry; |
| 995 | int err = 0; |
| 996 | |
| 997 | /* If we don't have the privroot located yet - go find it */ |
| 998 | inode_lock(d_inode(s->s_root)); |
| 999 | dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, |
| 1000 | strlen(PRIVROOT_NAME)); |
| 1001 | if (!IS_ERR(dentry)) { |
| 1002 | REISERFS_SB(s)->priv_root = dentry; |
| 1003 | d_set_d_op(dentry, &xattr_lookup_poison_ops); |
| 1004 | if (d_really_is_positive(dentry)) |
| 1005 | d_inode(dentry)->i_flags |= S_PRIVATE; |
| 1006 | } else |
| 1007 | err = PTR_ERR(dentry); |
| 1008 | inode_unlock(d_inode(s->s_root)); |
| 1009 | |
| 1010 | return err; |
| 1011 | } |
| 1012 | |
| 1013 | /* |
| 1014 | * We need to take a copy of the mount flags since things like |
| 1015 | * MS_RDONLY don't get set until *after* we're called. |
| 1016 | * mount_flags != mount_options |
| 1017 | */ |
| 1018 | int reiserfs_xattr_init(struct super_block *s, int mount_flags) |
| 1019 | { |
| 1020 | int err = 0; |
| 1021 | struct dentry *privroot = REISERFS_SB(s)->priv_root; |
| 1022 | |
| 1023 | err = xattr_mount_check(s); |
| 1024 | if (err) |
| 1025 | goto error; |
| 1026 | |
| 1027 | if (d_really_is_negative(privroot) && !(mount_flags & MS_RDONLY)) { |
| 1028 | inode_lock(d_inode(s->s_root)); |
| 1029 | err = create_privroot(REISERFS_SB(s)->priv_root); |
| 1030 | inode_unlock(d_inode(s->s_root)); |
| 1031 | } |
| 1032 | |
| 1033 | if (d_really_is_positive(privroot)) { |
| 1034 | s->s_xattr = reiserfs_xattr_handlers; |
| 1035 | inode_lock(d_inode(privroot)); |
| 1036 | if (!REISERFS_SB(s)->xattr_root) { |
| 1037 | struct dentry *dentry; |
| 1038 | |
| 1039 | dentry = lookup_one_len(XAROOT_NAME, privroot, |
| 1040 | strlen(XAROOT_NAME)); |
| 1041 | if (!IS_ERR(dentry)) |
| 1042 | REISERFS_SB(s)->xattr_root = dentry; |
| 1043 | else |
| 1044 | err = PTR_ERR(dentry); |
| 1045 | } |
| 1046 | inode_unlock(d_inode(privroot)); |
| 1047 | } |
| 1048 | |
| 1049 | error: |
| 1050 | if (err) { |
| 1051 | clear_bit(REISERFS_XATTRS_USER, &REISERFS_SB(s)->s_mount_opt); |
| 1052 | clear_bit(REISERFS_POSIXACL, &REISERFS_SB(s)->s_mount_opt); |
| 1053 | } |
| 1054 | |
| 1055 | /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ |
| 1056 | if (reiserfs_posixacl(s)) |
| 1057 | s->s_flags |= MS_POSIXACL; |
| 1058 | else |
| 1059 | s->s_flags &= ~MS_POSIXACL; |
| 1060 | |
| 1061 | return err; |
| 1062 | } |