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/cred.h>
   8 #include <linux/buffer_head.h>
   9
  10 #include "exfat_raw.h"
  11 #include "exfat_fs.h"
  12
  13 static int exfat_cont_expand(struct inode *inode, loff_t size)
  14 {
  15         struct address_space *mapping = inode->i_mapping;
  16         loff_t start = i_size_read(inode), count = size - i_size_read(inode);
  17         int err, err2;
  18
  19         err = generic_cont_expand_simple(inode, size);
  20         if (err)
  21                 return err;
  22
  23         inode->i_ctime = inode->i_mtime = current_time(inode);
  24         mark_inode_dirty(inode);
  25
  26         if (!IS_SYNC(inode))
  27                 return 0;
  28
  29         err = filemap_fdatawrite_range(mapping, start, start + count - 1);
  30         err2 = sync_mapping_buffers(mapping);
  31         if (!err)
  32                 err = err2;
  33         err2 = write_inode_now(inode, 1);
  34         if (!err)
  35                 err = err2;
  36         if (err)
  37                 return err;
  38
  39         return filemap_fdatawait_range(mapping, start, start + count - 1);
  40 }
  41
  42 static bool exfat_allow_set_time(struct exfat_sb_info *sbi, struct inode *inode)
  43 {
  44         mode_t allow_utime = sbi->options.allow_utime;
  45
  46         if (!uid_eq(current_fsuid(), inode->i_uid)) {
  47                 if (in_group_p(inode->i_gid))
  48                         allow_utime >>= 3;
  49                 if (allow_utime & MAY_WRITE)
  50                         return true;
  51         }
  52
  53         /* use a default check */
  54         return false;
  55 }
  56
  57 static int exfat_sanitize_mode(const struct exfat_sb_info *sbi,
  58                 struct inode *inode, umode_t *mode_ptr)
  59 {
  60         mode_t i_mode, mask, perm;
  61
  62         i_mode = inode->i_mode;
  63
  64         mask = (S_ISREG(i_mode) || S_ISLNK(i_mode)) ?
  65                 sbi->options.fs_fmask : sbi->options.fs_dmask;
  66         perm = *mode_ptr & ~(S_IFMT | mask);
  67
  68         /* Of the r and x bits, all (subject to umask) must be present.*/
  69         if ((perm & 0555) != (i_mode & 0555))
  70                 return -EPERM;
  71
  72         if (exfat_mode_can_hold_ro(inode)) {
  73                 /*
  74                  * Of the w bits, either all (subject to umask) or none must
  75                  * be present.
  76                  */
  77                 if ((perm & 0222) && ((perm & 0222) != (0222 & ~mask)))
  78                         return -EPERM;
  79         } else {
  80                 /*
  81                  * If exfat_mode_can_hold_ro(inode) is false, can't change
  82                  * w bits.
  83                  */
  84                 if ((perm & 0222) != (0222 & ~mask))
  85                         return -EPERM;
  86         }
  87
  88         *mode_ptr &= S_IFMT | perm;
  89
  90         return 0;
  91 }
  92
  93 /* resize the file length */
  94 int __exfat_truncate(struct inode *inode, loff_t new_size)
  95 {
  96         unsigned int num_clusters_new, num_clusters_phys;
  97         unsigned int last_clu = EXFAT_FREE_CLUSTER;
  98         struct exfat_chain clu;
  99         struct exfat_dentry *ep, *ep2;
 100         struct super_block *sb = inode->i_sb;
 101         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 102         struct exfat_inode_info *ei = EXFAT_I(inode);
 103         struct exfat_entry_set_cache *es = NULL;
 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_vol_flags(sb, VOL_DIRTY);
 111
 112         num_clusters_new = EXFAT_B_TO_CLU_ROUND_UP(i_size_read(inode), sbi);
 113         num_clusters_phys =
 114                 EXFAT_B_TO_CLU_ROUND_UP(EXFAT_I(inode)->i_size_ondisk, sbi);
 115
 116         exfat_chain_set(&clu, ei->start_clu, num_clusters_phys, ei->flags);
 117
 118         if (new_size > 0) {
 119                 /*
 120                  * Truncate FAT chain num_clusters after the first cluster
 121                  * num_clusters = min(new, phys);
 122                  */
 123                 unsigned int num_clusters =
 124                         min(num_clusters_new, num_clusters_phys);
 125
 126                 /*
 127                  * Follow FAT chain
 128                  * (defensive coding - works fine even with corrupted FAT table
 129                  */
 130                 if (clu.flags == ALLOC_NO_FAT_CHAIN) {
 131                         clu.dir += num_clusters;
 132                         clu.size -= num_clusters;
 133                 } else {
 134                         while (num_clusters > 0) {
 135                                 last_clu = clu.dir;
 136                                 if (exfat_get_next_cluster(sb, &(clu.dir)))
 137                                         return -EIO;
 138
 139                                 num_clusters--;
 140                                 clu.size--;
 141                         }
 142                 }
 143         } else {
 144                 ei->flags = ALLOC_NO_FAT_CHAIN;
 145                 ei->start_clu = EXFAT_EOF_CLUSTER;
 146         }
 147
 148         i_size_write(inode, new_size);
 149
 150         if (ei->type == TYPE_FILE)
 151                 ei->attr |= ATTR_ARCHIVE;
 152
 153         /* update the directory entry */
 154         if (!evict) {
 155                 struct timespec64 ts;
 156
 157                 es = exfat_get_dentry_set(sb, &(ei->dir), ei->entry,
 158                                 ES_ALL_ENTRIES, &ep);
 159                 if (!es)
 160                         return -EIO;
 161                 ep2 = ep + 1;
 162
 163                 ts = current_time(inode);
 164                 exfat_set_entry_time(sbi, &ts,
 165                                 &ep->dentry.file.modify_tz,
 166                                 &ep->dentry.file.modify_time,
 167                                 &ep->dentry.file.modify_date,
 168                                 &ep->dentry.file.modify_time_ms);
 169                 ep->dentry.file.attr = cpu_to_le16(ei->attr);
 170
 171                 /* File size should be zero if there is no cluster allocated */
 172                 if (ei->start_clu == EXFAT_EOF_CLUSTER) {
 173                         ep2->dentry.stream.valid_size = 0;
 174                         ep2->dentry.stream.size = 0;
 175                 } else {
 176                         ep2->dentry.stream.valid_size = cpu_to_le64(new_size);
 177                         ep2->dentry.stream.size = ep->dentry.stream.valid_size;
 178                 }
 179
 180                 if (new_size == 0) {
 181                         /* Any directory can not be truncated to zero */
 182                         WARN_ON(ei->type != TYPE_FILE);
 183
 184                         ep2->dentry.stream.flags = ALLOC_FAT_CHAIN;
 185                         ep2->dentry.stream.start_clu = EXFAT_FREE_CLUSTER;
 186                 }
 187
 188                 if (exfat_update_dir_chksum_with_entry_set(sb, es,
 189                     inode_needs_sync(inode)))
 190                         return -EIO;
 191                 kfree(es);
 192         }
 193
 194         /* cut off from the FAT chain */
 195         if (ei->flags == ALLOC_FAT_CHAIN && last_clu != EXFAT_FREE_CLUSTER &&
 196                         last_clu != EXFAT_EOF_CLUSTER) {
 197                 if (exfat_ent_set(sb, last_clu, EXFAT_EOF_CLUSTER))
 198                         return -EIO;
 199         }
 200
 201         /* invalidate cache and free the clusters */
 202         /* clear exfat cache */
 203         exfat_cache_inval_inode(inode);
 204
 205         /* hint information */
 206         ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
 207         ei->hint_bmap.clu = EXFAT_EOF_CLUSTER;
 208         if (ei->rwoffset > new_size)
 209                 ei->rwoffset = new_size;
 210
 211         /* hint_stat will be used if this is directory. */
 212         ei->hint_stat.eidx = 0;
 213         ei->hint_stat.clu = ei->start_clu;
 214         ei->hint_femp.eidx = EXFAT_HINT_NONE;
 215
 216         /* free the clusters */
 217         if (exfat_free_cluster(inode, &clu))
 218                 return -EIO;
 219
 220         exfat_set_vol_flags(sb, VOL_CLEAN);
 221
 222         return 0;
 223 }
 224
 225 void exfat_truncate(struct inode *inode, loff_t size)
 226 {
 227         struct super_block *sb = inode->i_sb;
 228         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 229         unsigned int blocksize = 1 << inode->i_blkbits;
 230         loff_t aligned_size;
 231         int err;
 232
 233         mutex_lock(&sbi->s_lock);
 234         if (EXFAT_I(inode)->start_clu == 0) {
 235                 /*
 236                  * Empty start_clu != ~0 (not allocated)
 237                  */
 238                 exfat_fs_error(sb, "tried to truncate zeroed cluster.");
 239                 goto write_size;
 240         }
 241
 242         err = __exfat_truncate(inode, i_size_read(inode));
 243         if (err)
 244                 goto write_size;
 245
 246         inode->i_ctime = inode->i_mtime = current_time(inode);
 247         if (IS_DIRSYNC(inode))
 248                 exfat_sync_inode(inode);
 249         else
 250                 mark_inode_dirty(inode);
 251
 252         inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size - 1)) &
 253                         ~(sbi->cluster_size - 1)) >> inode->i_blkbits;
 254 write_size:
 255         aligned_size = i_size_read(inode);
 256         if (aligned_size & (blocksize - 1)) {
 257                 aligned_size |= (blocksize - 1);
 258                 aligned_size++;
 259         }
 260
 261         if (EXFAT_I(inode)->i_size_ondisk > i_size_read(inode))
 262                 EXFAT_I(inode)->i_size_ondisk = aligned_size;
 263
 264         if (EXFAT_I(inode)->i_size_aligned > i_size_read(inode))
 265                 EXFAT_I(inode)->i_size_aligned = aligned_size;
 266         mutex_unlock(&sbi->s_lock);
 267 }
 268
 269 int exfat_getattr(const struct path *path, struct kstat *stat,
 270                 unsigned int request_mask, unsigned int query_flags)
 271 {
 272         struct inode *inode = d_backing_inode(path->dentry);
 273         struct exfat_inode_info *ei = EXFAT_I(inode);
 274
 275         generic_fillattr(inode, stat);
 276         exfat_truncate_atime(&stat->atime);
 277         stat->result_mask |= STATX_BTIME;
 278         stat->btime.tv_sec = ei->i_crtime.tv_sec;
 279         stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
 280         stat->blksize = EXFAT_SB(inode->i_sb)->cluster_size;
 281         return 0;
 282 }
 283
 284 int exfat_setattr(struct dentry *dentry, struct iattr *attr)
 285 {
 286         struct exfat_sb_info *sbi = EXFAT_SB(dentry->d_sb);
 287         struct inode *inode = dentry->d_inode;
 288         unsigned int ia_valid;
 289         int error;
 290
 291         if ((attr->ia_valid & ATTR_SIZE) &&
 292             attr->ia_size > i_size_read(inode)) {
 293                 error = exfat_cont_expand(inode, attr->ia_size);
 294                 if (error || attr->ia_valid == ATTR_SIZE)
 295                         return error;
 296                 attr->ia_valid &= ~ATTR_SIZE;
 297         }
 298
 299         /* Check for setting the inode time. */
 300         ia_valid = attr->ia_valid;
 301         if ((ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) &&
 302             exfat_allow_set_time(sbi, inode)) {
 303                 attr->ia_valid &= ~(ATTR_MTIME_SET | ATTR_ATIME_SET |
 304                                 ATTR_TIMES_SET);
 305         }
 306
 307         error = setattr_prepare(dentry, attr);
 308         attr->ia_valid = ia_valid;
 309         if (error)
 310                 goto out;
 311
 312         if (((attr->ia_valid & ATTR_UID) &&
 313              !uid_eq(attr->ia_uid, sbi->options.fs_uid)) ||
 314             ((attr->ia_valid & ATTR_GID) &&
 315              !gid_eq(attr->ia_gid, sbi->options.fs_gid)) ||
 316             ((attr->ia_valid & ATTR_MODE) &&
 317              (attr->ia_mode & ~(S_IFREG | S_IFLNK | S_IFDIR | 0777)))) {
 318                 error = -EPERM;
 319                 goto out;
 320         }
 321
 322         /*
 323          * We don't return -EPERM here. Yes, strange, but this is too
 324          * old behavior.
 325          */
 326         if (attr->ia_valid & ATTR_MODE) {
 327                 if (exfat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0)
 328                         attr->ia_valid &= ~ATTR_MODE;
 329         }
 330
 331         if (attr->ia_valid & ATTR_SIZE) {
 332                 error = exfat_block_truncate_page(inode, attr->ia_size);
 333                 if (error)
 334                         goto out;
 335
 336                 down_write(&EXFAT_I(inode)->truncate_lock);
 337                 truncate_setsize(inode, attr->ia_size);
 338                 exfat_truncate(inode, attr->ia_size);
 339                 up_write(&EXFAT_I(inode)->truncate_lock);
 340         }
 341
 342         setattr_copy(inode, attr);
 343         exfat_truncate_atime(&inode->i_atime);
 344         mark_inode_dirty(inode);
 345
 346 out:
 347         return error;
 348 }
 349
 350 const struct file_operations exfat_file_operations = {
 351         .llseek         = generic_file_llseek,
 352         .read_iter      = generic_file_read_iter,
 353         .write_iter     = generic_file_write_iter,
 354         .mmap           = generic_file_mmap,
 355         .fsync          = generic_file_fsync,
 356         .splice_read    = generic_file_splice_read,
 357         .splice_write   = iter_file_splice_write,
 358 };
 359
 360 const struct inode_operations exfat_file_inode_operations = {
 361         .setattr     = exfat_setattr,
 362         .getattr     = exfat_getattr,
 363 };