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