fs/exfat/file.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
   4  */
   5
   6 #include <linux/slab.h>
   7 #include <linux/compat.h>
   8 #include <linux/cred.h>
   9 #include <linux/buffer_head.h>
  10 #include <linux/blkdev.h>
  11
  12 #include "exfat_raw.h"
  13 #include "exfat_fs.h"
  14
  15 static int exfat_cont_expand(struct inode *inode, loff_t size)
  16 {
  17         struct address_space *mapping = inode->i_mapping;
  18         loff_t start = i_size_read(inode), count = size - i_size_read(inode);
  19         int err, err2;
  20
  21         err = generic_cont_expand_simple(inode, size);
  22         if (err)
  23                 return err;
  24
  25         inode->i_ctime = inode->i_mtime = current_time(inode);
  26         mark_inode_dirty(inode);
  27
  28         if (!IS_SYNC(inode))
  29                 return 0;
  30
  31         err = filemap_fdatawrite_range(mapping, start, start + count - 1);
  32         err2 = sync_mapping_buffers(mapping);
  33         if (!err)
  34                 err = err2;
  35         err2 = write_inode_now(inode, 1);
  36         if (!err)
  37                 err = err2;
  38         if (err)
  39                 return err;
  40
  41         return filemap_fdatawait_range(mapping, start, start + count - 1);
  42 }
  43
  44 static bool exfat_allow_set_time(struct exfat_sb_info *sbi, struct inode *inode)
  45 {
  46         mode_t allow_utime = sbi->options.allow_utime;
  47
  48         if (!uid_eq(current_fsuid(), inode->i_uid)) {
  49                 if (in_group_p(inode->i_gid))
  50                         allow_utime >>= 3;
  51                 if (allow_utime & MAY_WRITE)
  52                         return true;
  53         }
  54
  55         /* use a default check */
  56         return false;
  57 }
  58
  59 static int exfat_sanitize_mode(const struct exfat_sb_info *sbi,
  60                 struct inode *inode, umode_t *mode_ptr)
  61 {
  62         mode_t i_mode, mask, perm;
  63
  64         i_mode = inode->i_mode;
  65
  66         mask = (S_ISREG(i_mode) || S_ISLNK(i_mode)) ?
  67                 sbi->options.fs_fmask : sbi->options.fs_dmask;
  68         perm = *mode_ptr & ~(S_IFMT | mask);
  69
  70         /* Of the r and x bits, all (subject to umask) must be present.*/
  71         if ((perm & 0555) != (i_mode & 0555))
  72                 return -EPERM;
  73
  74         if (exfat_mode_can_hold_ro(inode)) {
  75                 /*
  76                  * Of the w bits, either all (subject to umask) or none must
  77                  * be present.
  78                  */
  79                 if ((perm & 0222) && ((perm & 0222) != (0222 & ~mask)))
  80                         return -EPERM;
  81         } else {
  82                 /*
  83                  * If exfat_mode_can_hold_ro(inode) is false, can't change
  84                  * w bits.
  85                  */
  86                 if ((perm & 0222) != (0222 & ~mask))
  87                         return -EPERM;
  88         }
  89
  90         *mode_ptr &= S_IFMT | perm;
  91
  92         return 0;
  93 }
  94
  95 /* resize the file length */
  96 int __exfat_truncate(struct inode *inode, loff_t new_size)
  97 {
  98         unsigned int num_clusters_new, num_clusters_phys;
  99         unsigned int last_clu = EXFAT_FREE_CLUSTER;
 100         struct exfat_chain clu;
 101         struct super_block *sb = inode->i_sb;
 102         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 103         struct exfat_inode_info *ei = EXFAT_I(inode);
 104         int evict = (ei->dir.dir == DIR_DELETED) ? 1 : 0;
 105
 106         /* check if the given file ID is opened */
 107         if (ei->type != TYPE_FILE && ei->type != TYPE_DIR)
 108                 return -EPERM;
 109
 110         exfat_set_volume_dirty(sb);
 111
 112         num_clusters_new = EXFAT_B_TO_CLU_ROUND_UP(i_size_read(inode), sbi);
 113         num_clusters_phys = EXFAT_B_TO_CLU_ROUND_UP(ei->i_size_ondisk, sbi);
 114
 115         exfat_chain_set(&clu, ei->start_clu, num_clusters_phys, ei->flags);
 116
 117         if (new_size > 0) {
 118                 /*
 119                  * Truncate FAT chain num_clusters after the first cluster
 120                  * num_clusters = min(new, phys);
 121                  */
 122                 unsigned int num_clusters =
 123                         min(num_clusters_new, num_clusters_phys);
 124
 125                 /*
 126                  * Follow FAT chain
 127                  * (defensive coding - works fine even with corrupted FAT table
 128                  */
 129                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
 130                         clu.dir += num_clusters;
 131                         clu.size -= num_clusters;
 132                 } else {
 133                         while (num_clusters > 0) {
 134                                 last_clu = clu.dir;
 135                                 if (exfat_get_next_cluster(sb, &(clu.dir)))
 136                                         return -EIO;
 137
 138                                 num_clusters--;
 139                                 clu.size--;
 140                         }
 141                 }
 142         } else {
 143                 ei->flags = ALLOC_NO_FAT_CHAIN;
 144                 ei->start_clu = EXFAT_EOF_CLUSTER;
 145         }
 146
 147         i_size_write(inode, new_size);
 148
 149         if (ei->type == TYPE_FILE)
 150                 ei->attr |= ATTR_ARCHIVE;
 151
 152         /* update the directory entry */
 153         if (!evict) {
 154                 struct timespec64 ts;
 155                 struct exfat_dentry *ep, *ep2;
 156                 struct exfat_entry_set_cache *es;
 157                 int err;
 158
 159                 es = exfat_get_dentry_set(sb, &(ei->dir), ei->entry,
 160                                 ES_ALL_ENTRIES);
 161                 if (!es)
 162                         return -EIO;
 163                 ep = exfat_get_dentry_cached(es, 0);
 164                 ep2 = exfat_get_dentry_cached(es, 1);
 165
 166                 ts = current_time(inode);
 167                 exfat_set_entry_time(sbi, &ts,
 168                                 &ep->dentry.file.modify_tz,
 169                                 &ep->dentry.file.modify_time,
 170                                 &ep->dentry.file.modify_date,
 171                                 &ep->dentry.file.modify_time_cs);
 172                 ep->dentry.file.attr = cpu_to_le16(ei->attr);
 173
 174                 /* File size should be zero if there is no cluster allocated */
 175                 if (ei->start_clu == EXFAT_EOF_CLUSTER) {
 176                         ep2->dentry.stream.valid_size = 0;
 177                         ep2->dentry.stream.size = 0;
 178                 } else {
 179                         ep2->dentry.stream.valid_size = cpu_to_le64(new_size);
 180                         ep2->dentry.stream.size = ep2->dentry.stream.valid_size;
 181                 }
 182
 183                 if (new_size == 0) {
 184                         /* Any directory can not be truncated to zero */
 185                         WARN_ON(ei->type != TYPE_FILE);
 186
 187                         ep2->dentry.stream.flags = ALLOC_FAT_CHAIN;
 188                         ep2->dentry.stream.start_clu = EXFAT_FREE_CLUSTER;
 189                 }
 190
 191                 exfat_update_dir_chksum_with_entry_set(es);
 192                 err = exfat_free_dentry_set(es, inode_needs_sync(inode));
 193                 if (err)
 194                         return err;
 195         }
 196
 197         /* cut off from the FAT chain */
 198         if (ei->flags == ALLOC_FAT_CHAIN && last_clu != EXFAT_FREE_CLUSTER &&
 199                         last_clu != EXFAT_EOF_CLUSTER) {
 200                 if (exfat_ent_set(sb, last_clu, EXFAT_EOF_CLUSTER))
 201                         return -EIO;
 202         }
 203
 204         /* invalidate cache and free the clusters */
 205         /* clear exfat cache */
 206         exfat_cache_inval_inode(inode);
 207
 208         /* hint information */
 209         ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
 210         ei->hint_bmap.clu = EXFAT_EOF_CLUSTER;
 211
 212         /* hint_stat will be used if this is directory. */
 213         ei->hint_stat.eidx = 0;
 214         ei->hint_stat.clu = ei->start_clu;
 215         ei->hint_femp.eidx = EXFAT_HINT_NONE;
 216
 217         /* free the clusters */
 218         if (exfat_free_cluster(inode, &clu))
 219                 return -EIO;
 220
 221         exfat_clear_volume_dirty(sb);
 222
 223         return 0;
 224 }
 225
 226 void exfat_truncate(struct inode *inode, loff_t size)
 227 {
 228         struct super_block *sb = inode->i_sb;
 229         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 230         struct exfat_inode_info *ei = EXFAT_I(inode);
 231         unsigned int blocksize = i_blocksize(inode);
 232         loff_t aligned_size;
 233         int err;
 234
 235         mutex_lock(&sbi->s_lock);
 236         if (ei->start_clu == 0) {
 237                 /*
 238                  * Empty start_clu != ~0 (not allocated)
 239                  */
 240                 exfat_fs_error(sb, "tried to truncate zeroed cluster.");
 241                 goto write_size;
 242         }
 243
 244         err = __exfat_truncate(inode, i_size_read(inode));
 245         if (err)
 246                 goto write_size;
 247
 248         inode->i_ctime = inode->i_mtime = current_time(inode);
 249         if (IS_DIRSYNC(inode))
 250                 exfat_sync_inode(inode);
 251         else
 252                 mark_inode_dirty(inode);
 253
 254         inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >>
 255                                 inode->i_blkbits;
 256 write_size:
 257         aligned_size = i_size_read(inode);
 258         if (aligned_size & (blocksize - 1)) {
 259                 aligned_size |= (blocksize - 1);
 260                 aligned_size++;
 261         }
 262
 263         if (ei->i_size_ondisk > i_size_read(inode))
 264                 ei->i_size_ondisk = aligned_size;
 265
 266         if (ei->i_size_aligned > i_size_read(inode))
 267                 ei->i_size_aligned = aligned_size;
 268         mutex_unlock(&sbi->s_lock);
 269 }
 270
 271 int exfat_getattr(struct user_namespace *mnt_uerns, const struct path *path,
 272                   struct kstat *stat, unsigned int request_mask,
 273                   unsigned int query_flags)
 274 {
 275         struct inode *inode = d_backing_inode(path->dentry);
 276         struct exfat_inode_info *ei = EXFAT_I(inode);
 277
 278         generic_fillattr(&init_user_ns, inode, stat);
 279         exfat_truncate_atime(&stat->atime);
 280         stat->result_mask |= STATX_BTIME;
 281         stat->btime.tv_sec = ei->i_crtime.tv_sec;
 282         stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
 283         stat->blksize = EXFAT_SB(inode->i_sb)->cluster_size;
 284         return 0;
 285 }
 286
 287 int exfat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 288                   struct iattr *attr)
 289 {
 290         struct exfat_sb_info *sbi = EXFAT_SB(dentry->d_sb);
 291         struct inode *inode = dentry->d_inode;
 292         unsigned int ia_valid;
 293         int error;
 294
 295         if ((attr->ia_valid & ATTR_SIZE) &&
 296             attr->ia_size > i_size_read(inode)) {
 297                 error = exfat_cont_expand(inode, attr->ia_size);
 298                 if (error || attr->ia_valid == ATTR_SIZE)
 299                         return error;
 300                 attr->ia_valid &= ~ATTR_SIZE;
 301         }
 302
 303         /* Check for setting the inode time. */
 304         ia_valid = attr->ia_valid;
 305         if ((ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) &&
 306             exfat_allow_set_time(sbi, inode)) {
 307                 attr->ia_valid &= ~(ATTR_MTIME_SET | ATTR_ATIME_SET |
 308                                 ATTR_TIMES_SET);
 309         }
 310
 311         error = setattr_prepare(&init_user_ns, dentry, attr);
 312         attr->ia_valid = ia_valid;
 313         if (error)
 314                 goto out;
 315
 316         if (((attr->ia_valid & ATTR_UID) &&
 317              !uid_eq(attr->ia_uid, sbi->options.fs_uid)) ||
 318             ((attr->ia_valid & ATTR_GID) &&
 319              !gid_eq(attr->ia_gid, sbi->options.fs_gid)) ||
 320             ((attr->ia_valid & ATTR_MODE) &&
 321              (attr->ia_mode & ~(S_IFREG | S_IFLNK | S_IFDIR | 0777)))) {
 322                 error = -EPERM;
 323                 goto out;
 324         }
 325
 326         /*
 327          * We don't return -EPERM here. Yes, strange, but this is too
 328          * old behavior.
 329          */
 330         if (attr->ia_valid & ATTR_MODE) {
 331                 if (exfat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0)
 332                         attr->ia_valid &= ~ATTR_MODE;
 333         }
 334
 335         if (attr->ia_valid & ATTR_SIZE) {
 336                 error = exfat_block_truncate_page(inode, attr->ia_size);
 337                 if (error)
 338                         goto out;
 339
 340                 down_write(&EXFAT_I(inode)->truncate_lock);
 341                 truncate_setsize(inode, attr->ia_size);
 342                 exfat_truncate(inode, attr->ia_size);
 343                 up_write(&EXFAT_I(inode)->truncate_lock);
 344         }
 345
 346         setattr_copy(&init_user_ns, inode, attr);
 347         exfat_truncate_atime(&inode->i_atime);
 348         mark_inode_dirty(inode);
 349
 350 out:
 351         return error;
 352 }
 353
 354 static int exfat_ioctl_fitrim(struct inode *inode, unsigned long arg)
 355 {
 356         struct request_queue *q = bdev_get_queue(inode->i_sb->s_bdev);
 357         struct fstrim_range range;
 358         int ret = 0;
 359
 360         if (!capable(CAP_SYS_ADMIN))
 361                 return -EPERM;
 362
 363         if (!blk_queue_discard(q))
 364                 return -EOPNOTSUPP;
 365
 366         if (copy_from_user(&range, (struct fstrim_range __user *)arg, sizeof(range)))
 367                 return -EFAULT;
 368
 369         range.minlen = max_t(unsigned int, range.minlen,
 370                                 q->limits.discard_granularity);
 371
 372         ret = exfat_trim_fs(inode, &range);
 373         if (ret < 0)
 374                 return ret;
 375
 376         if (copy_to_user((struct fstrim_range __user *)arg, &range, sizeof(range)))
 377                 return -EFAULT;
 378
 379         return 0;
 380 }
 381
 382 long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 383 {
 384         struct inode *inode = file_inode(filp);
 385
 386         switch (cmd) {
 387         case FITRIM:
 388                 return exfat_ioctl_fitrim(inode, arg);
 389         default:
 390                 return -ENOTTY;
 391         }
 392 }
 393
 394 #ifdef CONFIG_COMPAT
 395 long exfat_compat_ioctl(struct file *filp, unsigned int cmd,
 396                                 unsigned long arg)
 397 {
 398         return exfat_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
 399 }
 400 #endif
 401
 402 int exfat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 403 {
 404         struct inode *inode = filp->f_mapping->host;
 405         int err;
 406
 407         err = __generic_file_fsync(filp, start, end, datasync);
 408         if (err)
 409                 return err;
 410
 411         err = sync_blockdev(inode->i_sb->s_bdev);
 412         if (err)
 413                 return err;
 414
 415         return blkdev_issue_flush(inode->i_sb->s_bdev);
 416 }
 417
 418 const struct file_operations exfat_file_operations = {
 419         .llseek         = generic_file_llseek,
 420         .read_iter      = generic_file_read_iter,
 421         .write_iter     = generic_file_write_iter,
 422         .unlocked_ioctl = exfat_ioctl,
 423 #ifdef CONFIG_COMPAT
 424         .compat_ioctl = exfat_compat_ioctl,
 425 #endif
 426         .mmap           = generic_file_mmap,
 427         .fsync          = exfat_file_fsync,
 428         .splice_read    = generic_file_splice_read,
 429         .splice_write   = iter_file_splice_write,
 430 };
 431
 432 const struct inode_operations exfat_file_inode_operations = {
 433         .setattr     = exfat_setattr,
 434         .getattr     = exfat_getattr,
 435 };