fs/stat.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/stat.c
   4  *
   5  *  Copyright (C) 1991, 1992  Linus Torvalds
   6  */
   7
   8 #include <linux/export.h>
   9 #include <linux/mm.h>
  10 #include <linux/errno.h>
  11 #include <linux/file.h>
  12 #include <linux/highuid.h>
  13 #include <linux/fs.h>
  14 #include <linux/namei.h>
  15 #include <linux/security.h>
  16 #include <linux/cred.h>
  17 #include <linux/syscalls.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/compat.h>
  20
  21 #include <linux/uaccess.h>
  22 #include <asm/unistd.h>
  23
  24 #include "internal.h"
  25 #include "mount.h"
  26
  27 /**
  28  * generic_fillattr - Fill in the basic attributes from the inode struct
  29  * @inode: Inode to use as the source
  30  * @stat: Where to fill in the attributes
  31  *
  32  * Fill in the basic attributes in the kstat structure from data that's to be
  33  * found on the VFS inode structure.  This is the default if no getattr inode
  34  * operation is supplied.
  35  */
  36 void generic_fillattr(struct inode *inode, struct kstat *stat)
  37 {
  38         stat->dev = inode->i_sb->s_dev;
  39         stat->ino = inode->i_ino;
  40         stat->mode = inode->i_mode;
  41         stat->nlink = inode->i_nlink;
  42         stat->uid = inode->i_uid;
  43         stat->gid = inode->i_gid;
  44         stat->rdev = inode->i_rdev;
  45         stat->size = i_size_read(inode);
  46         stat->atime = inode->i_atime;
  47         stat->mtime = inode->i_mtime;
  48         stat->ctime = inode->i_ctime;
  49         stat->blksize = i_blocksize(inode);
  50         stat->blocks = inode->i_blocks;
  51 }
  52 EXPORT_SYMBOL(generic_fillattr);
  53
  54 /**
  55  * vfs_getattr_nosec - getattr without security checks
  56  * @path: file to get attributes from
  57  * @stat: structure to return attributes in
  58  * @request_mask: STATX_xxx flags indicating what the caller wants
  59  * @query_flags: Query mode (KSTAT_QUERY_FLAGS)
  60  *
  61  * Get attributes without calling security_inode_getattr.
  62  *
  63  * Currently the only caller other than vfs_getattr is internal to the
  64  * filehandle lookup code, which uses only the inode number and returns no
  65  * attributes to any user.  Any other code probably wants vfs_getattr.
  66  */
  67 int vfs_getattr_nosec(const struct path *path, struct kstat *stat,
  68                       u32 request_mask, unsigned int query_flags)
  69 {
  70         struct inode *inode = d_backing_inode(path->dentry);
  71
  72         memset(stat, 0, sizeof(*stat));
  73         stat->result_mask |= STATX_BASIC_STATS;
  74         query_flags &= KSTAT_QUERY_FLAGS;
  75
  76         /* allow the fs to override these if it really wants to */
  77         /* SB_NOATIME means filesystem supplies dummy atime value */
  78         if (inode->i_sb->s_flags & SB_NOATIME)
  79                 stat->result_mask &= ~STATX_ATIME;
  80         if (IS_AUTOMOUNT(inode))
  81                 stat->attributes |= STATX_ATTR_AUTOMOUNT;
  82
  83         if (inode->i_op->getattr)
  84                 return inode->i_op->getattr(path, stat, request_mask,
  85                                             query_flags);
  86
  87         generic_fillattr(inode, stat);
  88         return 0;
  89 }
  90 EXPORT_SYMBOL(vfs_getattr_nosec);
  91
  92 /*
  93  * vfs_getattr - Get the enhanced basic attributes of a file
  94  * @path: The file of interest
  95  * @stat: Where to return the statistics
  96  * @request_mask: STATX_xxx flags indicating what the caller wants
  97  * @query_flags: Query mode (KSTAT_QUERY_FLAGS)
  98  *
  99  * Ask the filesystem for a file's attributes.  The caller must indicate in
 100  * request_mask and query_flags to indicate what they want.
 101  *
 102  * If the file is remote, the filesystem can be forced to update the attributes
 103  * from the backing store by passing AT_STATX_FORCE_SYNC in query_flags or can
 104  * suppress the update by passing AT_STATX_DONT_SYNC.
 105  *
 106  * Bits must have been set in request_mask to indicate which attributes the
 107  * caller wants retrieving.  Any such attribute not requested may be returned
 108  * anyway, but the value may be approximate, and, if remote, may not have been
 109  * synchronised with the server.
 110  *
 111  * 0 will be returned on success, and a -ve error code if unsuccessful.
 112  */
 113 int vfs_getattr(const struct path *path, struct kstat *stat,
 114                 u32 request_mask, unsigned int query_flags)
 115 {
 116         int retval;
 117
 118         retval = security_inode_getattr(path);
 119         if (retval)
 120                 return retval;
 121         return vfs_getattr_nosec(path, stat, request_mask, query_flags);
 122 }
 123 EXPORT_SYMBOL(vfs_getattr);
 124
 125 /**
 126  * vfs_statx_fd - Get the enhanced basic attributes by file descriptor
 127  * @fd: The file descriptor referring to the file of interest
 128  * @stat: The result structure to fill in.
 129  * @request_mask: STATX_xxx flags indicating what the caller wants
 130  * @query_flags: Query mode (KSTAT_QUERY_FLAGS)
 131  *
 132  * This function is a wrapper around vfs_getattr().  The main difference is
 133  * that it uses a file descriptor to determine the file location.
 134  *
 135  * 0 will be returned on success, and a -ve error code if unsuccessful.
 136  */
 137 int vfs_statx_fd(unsigned int fd, struct kstat *stat,
 138                  u32 request_mask, unsigned int query_flags)
 139 {
 140         struct fd f;
 141         int error = -EBADF;
 142
 143         if (query_flags & ~KSTAT_QUERY_FLAGS)
 144                 return -EINVAL;
 145
 146         f = fdget_raw(fd);
 147         if (f.file) {
 148                 error = vfs_getattr(&f.file->f_path, stat,
 149                                     request_mask, query_flags);
 150                 fdput(f);
 151         }
 152         return error;
 153 }
 154 EXPORT_SYMBOL(vfs_statx_fd);
 155
 156 inline unsigned vfs_stat_set_lookup_flags(unsigned *lookup_flags, int flags)
 157 {
 158         if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
 159                        AT_EMPTY_PATH | KSTAT_QUERY_FLAGS)) != 0)
 160                 return -EINVAL;
 161
 162         *lookup_flags = LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT;
 163         if (flags & AT_SYMLINK_NOFOLLOW)
 164                 *lookup_flags &= ~LOOKUP_FOLLOW;
 165         if (flags & AT_NO_AUTOMOUNT)
 166                 *lookup_flags &= ~LOOKUP_AUTOMOUNT;
 167         if (flags & AT_EMPTY_PATH)
 168                 *lookup_flags |= LOOKUP_EMPTY;
 169
 170         return 0;
 171 }
 172
 173 /**
 174  * vfs_statx - Get basic and extra attributes by filename
 175  * @dfd: A file descriptor representing the base dir for a relative filename
 176  * @filename: The name of the file of interest
 177  * @flags: Flags to control the query
 178  * @stat: The result structure to fill in.
 179  * @request_mask: STATX_xxx flags indicating what the caller wants
 180  *
 181  * This function is a wrapper around vfs_getattr().  The main difference is
 182  * that it uses a filename and base directory to determine the file location.
 183  * Additionally, the use of AT_SYMLINK_NOFOLLOW in flags will prevent a symlink
 184  * at the given name from being referenced.
 185  *
 186  * 0 will be returned on success, and a -ve error code if unsuccessful.
 187  */
 188 int vfs_statx(int dfd, const char __user *filename, int flags,
 189               struct kstat *stat, u32 request_mask)
 190 {
 191         struct path path;
 192         int error = -EINVAL;
 193         unsigned lookup_flags;
 194
 195         if (vfs_stat_set_lookup_flags(&lookup_flags, flags))
 196                 return -EINVAL;
 197 retry:
 198         error = user_path_at(dfd, filename, lookup_flags, &path);
 199         if (error)
 200                 goto out;
 201
 202         error = vfs_getattr(&path, stat, request_mask, flags);
 203         stat->mnt_id = real_mount(path.mnt)->mnt_id;
 204         stat->result_mask |= STATX_MNT_ID;
 205         if (path.mnt->mnt_root == path.dentry)
 206                 stat->attributes |= STATX_ATTR_MOUNT_ROOT;
 207         stat->attributes_mask |= STATX_ATTR_MOUNT_ROOT;
 208         path_put(&path);
 209         if (retry_estale(error, lookup_flags)) {
 210                 lookup_flags |= LOOKUP_REVAL;
 211                 goto retry;
 212         }
 213 out:
 214         return error;
 215 }
 216 EXPORT_SYMBOL(vfs_statx);
 217
 218
 219 #ifdef __ARCH_WANT_OLD_STAT
 220
 221 /*
 222  * For backward compatibility?  Maybe this should be moved
 223  * into arch/i386 instead?
 224  */
 225 static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
 226 {
 227         static int warncount = 5;
 228         struct __old_kernel_stat tmp;
 229
 230         if (warncount > 0) {
 231                 warncount--;
 232                 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
 233                         current->comm);
 234         } else if (warncount < 0) {
 235                 /* it's laughable, but... */
 236                 warncount = 0;
 237         }
 238
 239         memset(&tmp, 0, sizeof(struct __old_kernel_stat));
 240         tmp.st_dev = old_encode_dev(stat->dev);
 241         tmp.st_ino = stat->ino;
 242         if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
 243                 return -EOVERFLOW;
 244         tmp.st_mode = stat->mode;
 245         tmp.st_nlink = stat->nlink;
 246         if (tmp.st_nlink != stat->nlink)
 247                 return -EOVERFLOW;
 248         SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
 249         SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
 250         tmp.st_rdev = old_encode_dev(stat->rdev);
 251 #if BITS_PER_LONG == 32
 252         if (stat->size > MAX_NON_LFS)
 253                 return -EOVERFLOW;
 254 #endif
 255         tmp.st_size = stat->size;
 256         tmp.st_atime = stat->atime.tv_sec;
 257         tmp.st_mtime = stat->mtime.tv_sec;
 258         tmp.st_ctime = stat->ctime.tv_sec;
 259         return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
 260 }
 261
 262 SYSCALL_DEFINE2(stat, const char __user *, filename,
 263                 struct __old_kernel_stat __user *, statbuf)
 264 {
 265         struct kstat stat;
 266         int error;
 267
 268         error = vfs_stat(filename, &stat);
 269         if (error)
 270                 return error;
 271
 272         return cp_old_stat(&stat, statbuf);
 273 }
 274
 275 SYSCALL_DEFINE2(lstat, const char __user *, filename,
 276                 struct __old_kernel_stat __user *, statbuf)
 277 {
 278         struct kstat stat;
 279         int error;
 280
 281         error = vfs_lstat(filename, &stat);
 282         if (error)
 283                 return error;
 284
 285         return cp_old_stat(&stat, statbuf);
 286 }
 287
 288 SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
 289 {
 290         struct kstat stat;
 291         int error = vfs_fstat(fd, &stat);
 292
 293         if (!error)
 294                 error = cp_old_stat(&stat, statbuf);
 295
 296         return error;
 297 }
 298
 299 #endif /* __ARCH_WANT_OLD_STAT */
 300
 301 #ifdef __ARCH_WANT_NEW_STAT
 302
 303 #if BITS_PER_LONG == 32
 304 #  define choose_32_64(a,b) a
 305 #else
 306 #  define choose_32_64(a,b) b
 307 #endif
 308
 309 #define valid_dev(x)  choose_32_64(old_valid_dev(x),true)
 310 #define encode_dev(x) choose_32_64(old_encode_dev,new_encode_dev)(x)
 311
 312 #ifndef INIT_STRUCT_STAT_PADDING
 313 #  define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st))
 314 #endif
 315
 316 static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
 317 {
 318         struct stat tmp;
 319
 320         if (!valid_dev(stat->dev) || !valid_dev(stat->rdev))
 321                 return -EOVERFLOW;
 322 #if BITS_PER_LONG == 32
 323         if (stat->size > MAX_NON_LFS)
 324                 return -EOVERFLOW;
 325 #endif
 326
 327         INIT_STRUCT_STAT_PADDING(tmp);
 328         tmp.st_dev = encode_dev(stat->dev);
 329         tmp.st_ino = stat->ino;
 330         if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
 331                 return -EOVERFLOW;
 332         tmp.st_mode = stat->mode;
 333         tmp.st_nlink = stat->nlink;
 334         if (tmp.st_nlink != stat->nlink)
 335                 return -EOVERFLOW;
 336         SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
 337         SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
 338         tmp.st_rdev = encode_dev(stat->rdev);
 339         tmp.st_size = stat->size;
 340         tmp.st_atime = stat->atime.tv_sec;
 341         tmp.st_mtime = stat->mtime.tv_sec;
 342         tmp.st_ctime = stat->ctime.tv_sec;
 343 #ifdef STAT_HAVE_NSEC
 344         tmp.st_atime_nsec = stat->atime.tv_nsec;
 345         tmp.st_mtime_nsec = stat->mtime.tv_nsec;
 346         tmp.st_ctime_nsec = stat->ctime.tv_nsec;
 347 #endif
 348         tmp.st_blocks = stat->blocks;
 349         tmp.st_blksize = stat->blksize;
 350         return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
 351 }
 352
 353 SYSCALL_DEFINE2(newstat, const char __user *, filename,
 354                 struct stat __user *, statbuf)
 355 {
 356         struct kstat stat;
 357         int error = vfs_stat(filename, &stat);
 358
 359         if (error)
 360                 return error;
 361         return cp_new_stat(&stat, statbuf);
 362 }
 363
 364 SYSCALL_DEFINE2(newlstat, const char __user *, filename,
 365                 struct stat __user *, statbuf)
 366 {
 367         struct kstat stat;
 368         int error;
 369
 370         error = vfs_lstat(filename, &stat);
 371         if (error)
 372                 return error;
 373
 374         return cp_new_stat(&stat, statbuf);
 375 }
 376
 377 #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
 378 SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
 379                 struct stat __user *, statbuf, int, flag)
 380 {
 381         struct kstat stat;
 382         int error;
 383
 384         error = vfs_fstatat(dfd, filename, &stat, flag);
 385         if (error)
 386                 return error;
 387         return cp_new_stat(&stat, statbuf);
 388 }
 389 #endif
 390
 391 SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
 392 {
 393         struct kstat stat;
 394         int error = vfs_fstat(fd, &stat);
 395
 396         if (!error)
 397                 error = cp_new_stat(&stat, statbuf);
 398
 399         return error;
 400 }
 401 #endif
 402
 403 static int do_readlinkat(int dfd, const char __user *pathname,
 404                          char __user *buf, int bufsiz)
 405 {
 406         struct path path;
 407         int error;
 408         int empty = 0;
 409         unsigned int lookup_flags = LOOKUP_EMPTY;
 410
 411         if (bufsiz <= 0)
 412                 return -EINVAL;
 413
 414 retry:
 415         error = user_path_at_empty(dfd, pathname, lookup_flags, &path, &empty);
 416         if (!error) {
 417                 struct inode *inode = d_backing_inode(path.dentry);
 418
 419                 error = empty ? -ENOENT : -EINVAL;
 420                 /*
 421                  * AFS mountpoints allow readlink(2) but are not symlinks
 422                  */
 423                 if (d_is_symlink(path.dentry) || inode->i_op->readlink) {
 424                         error = security_inode_readlink(path.dentry);
 425                         if (!error) {
 426                                 touch_atime(&path);
 427                                 error = vfs_readlink(path.dentry, buf, bufsiz);
 428                         }
 429                 }
 430                 path_put(&path);
 431                 if (retry_estale(error, lookup_flags)) {
 432                         lookup_flags |= LOOKUP_REVAL;
 433                         goto retry;
 434                 }
 435         }
 436         return error;
 437 }
 438
 439 SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
 440                 char __user *, buf, int, bufsiz)
 441 {
 442         return do_readlinkat(dfd, pathname, buf, bufsiz);
 443 }
 444
 445 SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
 446                 int, bufsiz)
 447 {
 448         return do_readlinkat(AT_FDCWD, path, buf, bufsiz);
 449 }
 450
 451
 452 /* ---------- LFS-64 ----------- */
 453 #if defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_COMPAT_STAT64)
 454
 455 #ifndef INIT_STRUCT_STAT64_PADDING
 456 #  define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st))
 457 #endif
 458
 459 static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
 460 {
 461         struct stat64 tmp;
 462
 463         INIT_STRUCT_STAT64_PADDING(tmp);
 464 #ifdef CONFIG_MIPS
 465         /* mips has weird padding, so we don't get 64 bits there */
 466         tmp.st_dev = new_encode_dev(stat->dev);
 467         tmp.st_rdev = new_encode_dev(stat->rdev);
 468 #else
 469         tmp.st_dev = huge_encode_dev(stat->dev);
 470         tmp.st_rdev = huge_encode_dev(stat->rdev);
 471 #endif
 472         tmp.st_ino = stat->ino;
 473         if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
 474                 return -EOVERFLOW;
 475 #ifdef STAT64_HAS_BROKEN_ST_INO
 476         tmp.__st_ino = stat->ino;
 477 #endif
 478         tmp.st_mode = stat->mode;
 479         tmp.st_nlink = stat->nlink;
 480         tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
 481         tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
 482         tmp.st_atime = stat->atime.tv_sec;
 483         tmp.st_atime_nsec = stat->atime.tv_nsec;
 484         tmp.st_mtime = stat->mtime.tv_sec;
 485         tmp.st_mtime_nsec = stat->mtime.tv_nsec;
 486         tmp.st_ctime = stat->ctime.tv_sec;
 487         tmp.st_ctime_nsec = stat->ctime.tv_nsec;
 488         tmp.st_size = stat->size;
 489         tmp.st_blocks = stat->blocks;
 490         tmp.st_blksize = stat->blksize;
 491         return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
 492 }
 493
 494 SYSCALL_DEFINE2(stat64, const char __user *, filename,
 495                 struct stat64 __user *, statbuf)
 496 {
 497         struct kstat stat;
 498         int error = vfs_stat(filename, &stat);
 499
 500         if (!error)
 501                 error = cp_new_stat64(&stat, statbuf);
 502
 503         return error;
 504 }
 505
 506 SYSCALL_DEFINE2(lstat64, const char __user *, filename,
 507                 struct stat64 __user *, statbuf)
 508 {
 509         struct kstat stat;
 510         int error = vfs_lstat(filename, &stat);
 511
 512         if (!error)
 513                 error = cp_new_stat64(&stat, statbuf);
 514
 515         return error;
 516 }
 517
 518 SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
 519 {
 520         struct kstat stat;
 521         int error = vfs_fstat(fd, &stat);
 522
 523         if (!error)
 524                 error = cp_new_stat64(&stat, statbuf);
 525
 526         return error;
 527 }
 528
 529 SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
 530                 struct stat64 __user *, statbuf, int, flag)
 531 {
 532         struct kstat stat;
 533         int error;
 534
 535         error = vfs_fstatat(dfd, filename, &stat, flag);
 536         if (error)
 537                 return error;
 538         return cp_new_stat64(&stat, statbuf);
 539 }
 540 #endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */
 541
 542 noinline_for_stack int
 543 cp_statx(const struct kstat *stat, struct statx __user *buffer)
 544 {
 545         struct statx tmp;
 546
 547         memset(&tmp, 0, sizeof(tmp));
 548
 549         tmp.stx_mask = stat->result_mask;
 550         tmp.stx_blksize = stat->blksize;
 551         tmp.stx_attributes = stat->attributes;
 552         tmp.stx_nlink = stat->nlink;
 553         tmp.stx_uid = from_kuid_munged(current_user_ns(), stat->uid);
 554         tmp.stx_gid = from_kgid_munged(current_user_ns(), stat->gid);
 555         tmp.stx_mode = stat->mode;
 556         tmp.stx_ino = stat->ino;
 557         tmp.stx_size = stat->size;
 558         tmp.stx_blocks = stat->blocks;
 559         tmp.stx_attributes_mask = stat->attributes_mask;
 560         tmp.stx_atime.tv_sec = stat->atime.tv_sec;
 561         tmp.stx_atime.tv_nsec = stat->atime.tv_nsec;
 562         tmp.stx_btime.tv_sec = stat->btime.tv_sec;
 563         tmp.stx_btime.tv_nsec = stat->btime.tv_nsec;
 564         tmp.stx_ctime.tv_sec = stat->ctime.tv_sec;
 565         tmp.stx_ctime.tv_nsec = stat->ctime.tv_nsec;
 566         tmp.stx_mtime.tv_sec = stat->mtime.tv_sec;
 567         tmp.stx_mtime.tv_nsec = stat->mtime.tv_nsec;
 568         tmp.stx_rdev_major = MAJOR(stat->rdev);
 569         tmp.stx_rdev_minor = MINOR(stat->rdev);
 570         tmp.stx_dev_major = MAJOR(stat->dev);
 571         tmp.stx_dev_minor = MINOR(stat->dev);
 572         tmp.stx_mnt_id = stat->mnt_id;
 573
 574         return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 575 }
 576
 577 /**
 578  * sys_statx - System call to get enhanced stats
 579  * @dfd: Base directory to pathwalk from *or* fd to stat.
 580  * @filename: File to stat or "" with AT_EMPTY_PATH
 581  * @flags: AT_* flags to control pathwalk.
 582  * @mask: Parts of statx struct actually required.
 583  * @buffer: Result buffer.
 584  *
 585  * Note that fstat() can be emulated by setting dfd to the fd of interest,
 586  * supplying "" as the filename and setting AT_EMPTY_PATH in the flags.
 587  */
 588 SYSCALL_DEFINE5(statx,
 589                 int, dfd, const char __user *, filename, unsigned, flags,
 590                 unsigned int, mask,
 591                 struct statx __user *, buffer)
 592 {
 593         struct kstat stat;
 594         int error;
 595
 596         if (mask & STATX__RESERVED)
 597                 return -EINVAL;
 598         if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
 599                 return -EINVAL;
 600
 601         error = vfs_statx(dfd, filename, flags, &stat, mask);
 602         if (error)
 603                 return error;
 604
 605         return cp_statx(&stat, buffer);
 606 }
 607
 608 #ifdef CONFIG_COMPAT
 609 static int cp_compat_stat(struct kstat *stat, struct compat_stat __user *ubuf)
 610 {
 611         struct compat_stat tmp;
 612
 613         if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev))
 614                 return -EOVERFLOW;
 615
 616         memset(&tmp, 0, sizeof(tmp));
 617         tmp.st_dev = old_encode_dev(stat->dev);
 618         tmp.st_ino = stat->ino;
 619         if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
 620                 return -EOVERFLOW;
 621         tmp.st_mode = stat->mode;
 622         tmp.st_nlink = stat->nlink;
 623         if (tmp.st_nlink != stat->nlink)
 624                 return -EOVERFLOW;
 625         SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
 626         SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
 627         tmp.st_rdev = old_encode_dev(stat->rdev);
 628         if ((u64) stat->size > MAX_NON_LFS)
 629                 return -EOVERFLOW;
 630         tmp.st_size = stat->size;
 631         tmp.st_atime = stat->atime.tv_sec;
 632         tmp.st_atime_nsec = stat->atime.tv_nsec;
 633         tmp.st_mtime = stat->mtime.tv_sec;
 634         tmp.st_mtime_nsec = stat->mtime.tv_nsec;
 635         tmp.st_ctime = stat->ctime.tv_sec;
 636         tmp.st_ctime_nsec = stat->ctime.tv_nsec;
 637         tmp.st_blocks = stat->blocks;
 638         tmp.st_blksize = stat->blksize;
 639         return copy_to_user(ubuf, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 640 }
 641
 642 COMPAT_SYSCALL_DEFINE2(newstat, const char __user *, filename,
 643                        struct compat_stat __user *, statbuf)
 644 {
 645         struct kstat stat;
 646         int error;
 647
 648         error = vfs_stat(filename, &stat);
 649         if (error)
 650                 return error;
 651         return cp_compat_stat(&stat, statbuf);
 652 }
 653
 654 COMPAT_SYSCALL_DEFINE2(newlstat, const char __user *, filename,
 655                        struct compat_stat __user *, statbuf)
 656 {
 657         struct kstat stat;
 658         int error;
 659
 660         error = vfs_lstat(filename, &stat);
 661         if (error)
 662                 return error;
 663         return cp_compat_stat(&stat, statbuf);
 664 }
 665
 666 #ifndef __ARCH_WANT_STAT64
 667 COMPAT_SYSCALL_DEFINE4(newfstatat, unsigned int, dfd,
 668                        const char __user *, filename,
 669                        struct compat_stat __user *, statbuf, int, flag)
 670 {
 671         struct kstat stat;
 672         int error;
 673
 674         error = vfs_fstatat(dfd, filename, &stat, flag);
 675         if (error)
 676                 return error;
 677         return cp_compat_stat(&stat, statbuf);
 678 }
 679 #endif
 680
 681 COMPAT_SYSCALL_DEFINE2(newfstat, unsigned int, fd,
 682                        struct compat_stat __user *, statbuf)
 683 {
 684         struct kstat stat;
 685         int error = vfs_fstat(fd, &stat);
 686
 687         if (!error)
 688                 error = cp_compat_stat(&stat, statbuf);
 689         return error;
 690 }
 691 #endif
 692
 693 /* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
 694 void __inode_add_bytes(struct inode *inode, loff_t bytes)
 695 {
 696         inode->i_blocks += bytes >> 9;
 697         bytes &= 511;
 698         inode->i_bytes += bytes;
 699         if (inode->i_bytes >= 512) {
 700                 inode->i_blocks++;
 701                 inode->i_bytes -= 512;
 702         }
 703 }
 704 EXPORT_SYMBOL(__inode_add_bytes);
 705
 706 void inode_add_bytes(struct inode *inode, loff_t bytes)
 707 {
 708         spin_lock(&inode->i_lock);
 709         __inode_add_bytes(inode, bytes);
 710         spin_unlock(&inode->i_lock);
 711 }
 712
 713 EXPORT_SYMBOL(inode_add_bytes);
 714
 715 void __inode_sub_bytes(struct inode *inode, loff_t bytes)
 716 {
 717         inode->i_blocks -= bytes >> 9;
 718         bytes &= 511;
 719         if (inode->i_bytes < bytes) {
 720                 inode->i_blocks--;
 721                 inode->i_bytes += 512;
 722         }
 723         inode->i_bytes -= bytes;
 724 }
 725
 726 EXPORT_SYMBOL(__inode_sub_bytes);
 727
 728 void inode_sub_bytes(struct inode *inode, loff_t bytes)
 729 {
 730         spin_lock(&inode->i_lock);
 731         __inode_sub_bytes(inode, bytes);
 732         spin_unlock(&inode->i_lock);
 733 }
 734
 735 EXPORT_SYMBOL(inode_sub_bytes);
 736
 737 loff_t inode_get_bytes(struct inode *inode)
 738 {
 739         loff_t ret;
 740
 741         spin_lock(&inode->i_lock);
 742         ret = __inode_get_bytes(inode);
 743         spin_unlock(&inode->i_lock);
 744         return ret;
 745 }
 746
 747 EXPORT_SYMBOL(inode_get_bytes);
 748
 749 void inode_set_bytes(struct inode *inode, loff_t bytes)
 750 {
 751         /* Caller is here responsible for sufficient locking
 752          * (ie. inode->i_lock) */
 753         inode->i_blocks = bytes >> 9;
 754         inode->i_bytes = bytes & 511;
 755 }
 756
 757 EXPORT_SYMBOL(inode_set_bytes);