fs/ext4/file.c

   1 /*
   2  *  linux/fs/ext4/file.c
   3  *
   4  * Copyright (C) 1992, 1993, 1994, 1995
   5  * Remy Card (card@masi.ibp.fr)
   6  * Laboratoire MASI - Institut Blaise Pascal
   7  * Universite Pierre et Marie Curie (Paris VI)
   8  *
   9  *  from
  10  *
  11  *  linux/fs/minix/file.c
  12  *
  13  *  Copyright (C) 1991, 1992  Linus Torvalds
  14  *
  15  *  ext4 fs regular file handling primitives
  16  *
  17  *  64-bit file support on 64-bit platforms by Jakub Jelinek
  18  *      (jj@sunsite.ms.mff.cuni.cz)
  19  */
  20
  21 #include <linux/time.h>
  22 #include <linux/fs.h>
  23 #include <linux/mount.h>
  24 #include <linux/path.h>
  25 #include <linux/dax.h>
  26 #include <linux/quotaops.h>
  27 #include <linux/pagevec.h>
  28 #include <linux/uio.h>
  29 #include "ext4.h"
  30 #include "ext4_jbd2.h"
  31 #include "xattr.h"
  32 #include "acl.h"
  33
  34 #ifdef CONFIG_FS_DAX
  35 static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
  36 {
  37         struct inode *inode = file_inode(iocb->ki_filp);
  38         ssize_t ret;
  39
  40         inode_lock_shared(inode);
  41         /*
  42          * Recheck under inode lock - at this point we are sure it cannot
  43          * change anymore
  44          */
  45         if (!IS_DAX(inode)) {
  46                 inode_unlock_shared(inode);
  47                 /* Fallback to buffered IO in case we cannot support DAX */
  48                 return generic_file_read_iter(iocb, to);
  49         }
  50         ret = dax_iomap_rw(iocb, to, &ext4_iomap_ops);
  51         inode_unlock_shared(inode);
  52
  53         file_accessed(iocb->ki_filp);
  54         return ret;
  55 }
  56 #endif
  57
  58 static ssize_t ext4_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
  59 {
  60         if (!iov_iter_count(to))
  61                 return 0; /* skip atime */
  62
  63 #ifdef CONFIG_FS_DAX
  64         if (IS_DAX(file_inode(iocb->ki_filp)))
  65                 return ext4_dax_read_iter(iocb, to);
  66 #endif
  67         return generic_file_read_iter(iocb, to);
  68 }
  69
  70 /*
  71  * Called when an inode is released. Note that this is different
  72  * from ext4_file_open: open gets called at every open, but release
  73  * gets called only when /all/ the files are closed.
  74  */
  75 static int ext4_release_file(struct inode *inode, struct file *filp)
  76 {
  77         if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
  78                 ext4_alloc_da_blocks(inode);
  79                 ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
  80         }
  81         /* if we are the last writer on the inode, drop the block reservation */
  82         if ((filp->f_mode & FMODE_WRITE) &&
  83                         (atomic_read(&inode->i_writecount) == 1) &&
  84                         !EXT4_I(inode)->i_reserved_data_blocks)
  85         {
  86                 down_write(&EXT4_I(inode)->i_data_sem);
  87                 ext4_discard_preallocations(inode);
  88                 up_write(&EXT4_I(inode)->i_data_sem);
  89         }
  90         if (is_dx(inode) && filp->private_data)
  91                 ext4_htree_free_dir_info(filp->private_data);
  92
  93         return 0;
  94 }
  95
  96 static void ext4_unwritten_wait(struct inode *inode)
  97 {
  98         wait_queue_head_t *wq = ext4_ioend_wq(inode);
  99
 100         wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_unwritten) == 0));
 101 }
 102
 103 /*
 104  * This tests whether the IO in question is block-aligned or not.
 105  * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
 106  * are converted to written only after the IO is complete.  Until they are
 107  * mapped, these blocks appear as holes, so dio_zero_block() will assume that
 108  * it needs to zero out portions of the start and/or end block.  If 2 AIO
 109  * threads are at work on the same unwritten block, they must be synchronized
 110  * or one thread will zero the other's data, causing corruption.
 111  */
 112 static int
 113 ext4_unaligned_aio(struct inode *inode, struct iov_iter *from, loff_t pos)
 114 {
 115         struct super_block *sb = inode->i_sb;
 116         int blockmask = sb->s_blocksize - 1;
 117
 118         if (pos >= i_size_read(inode))
 119                 return 0;
 120
 121         if ((pos | iov_iter_alignment(from)) & blockmask)
 122                 return 1;
 123
 124         return 0;
 125 }
 126
 127 /* Is IO overwriting allocated and initialized blocks? */
 128 static bool ext4_overwrite_io(struct inode *inode, loff_t pos, loff_t len)
 129 {
 130         struct ext4_map_blocks map;
 131         unsigned int blkbits = inode->i_blkbits;
 132         int err, blklen;
 133
 134         if (pos + len > i_size_read(inode))
 135                 return false;
 136
 137         map.m_lblk = pos >> blkbits;
 138         map.m_len = EXT4_MAX_BLOCKS(len, pos, blkbits);
 139         blklen = map.m_len;
 140
 141         err = ext4_map_blocks(NULL, inode, &map, 0);
 142         /*
 143          * 'err==len' means that all of the blocks have been preallocated,
 144          * regardless of whether they have been initialized or not. To exclude
 145          * unwritten extents, we need to check m_flags.
 146          */
 147         return err == blklen && (map.m_flags & EXT4_MAP_MAPPED);
 148 }
 149
 150 static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from)
 151 {
 152         struct inode *inode = file_inode(iocb->ki_filp);
 153         ssize_t ret;
 154
 155         ret = generic_write_checks(iocb, from);
 156         if (ret <= 0)
 157                 return ret;
 158         /*
 159          * If we have encountered a bitmap-format file, the size limit
 160          * is smaller than s_maxbytes, which is for extent-mapped files.
 161          */
 162         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
 163                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 164
 165                 if (iocb->ki_pos >= sbi->s_bitmap_maxbytes)
 166                         return -EFBIG;
 167                 iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos);
 168         }
 169         return iov_iter_count(from);
 170 }
 171
 172 #ifdef CONFIG_FS_DAX
 173 static ssize_t
 174 ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
 175 {
 176         struct inode *inode = file_inode(iocb->ki_filp);
 177         ssize_t ret;
 178         bool overwrite = false;
 179
 180         inode_lock(inode);
 181         ret = ext4_write_checks(iocb, from);
 182         if (ret <= 0)
 183                 goto out;
 184         ret = file_remove_privs(iocb->ki_filp);
 185         if (ret)
 186                 goto out;
 187         ret = file_update_time(iocb->ki_filp);
 188         if (ret)
 189                 goto out;
 190
 191         if (ext4_overwrite_io(inode, iocb->ki_pos, iov_iter_count(from))) {
 192                 overwrite = true;
 193                 downgrade_write(&inode->i_rwsem);
 194         }
 195         ret = dax_iomap_rw(iocb, from, &ext4_iomap_ops);
 196 out:
 197         if (!overwrite)
 198                 inode_unlock(inode);
 199         else
 200                 inode_unlock_shared(inode);
 201         if (ret > 0)
 202                 ret = generic_write_sync(iocb, ret);
 203         return ret;
 204 }
 205 #endif
 206
 207 static ssize_t
 208 ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 209 {
 210         struct inode *inode = file_inode(iocb->ki_filp);
 211         int o_direct = iocb->ki_flags & IOCB_DIRECT;
 212         int unaligned_aio = 0;
 213         int overwrite = 0;
 214         ssize_t ret;
 215
 216 #ifdef CONFIG_FS_DAX
 217         if (IS_DAX(inode))
 218                 return ext4_dax_write_iter(iocb, from);
 219 #endif
 220
 221         inode_lock(inode);
 222         ret = ext4_write_checks(iocb, from);
 223         if (ret <= 0)
 224                 goto out;
 225
 226         /*
 227          * Unaligned direct AIO must be serialized among each other as zeroing
 228          * of partial blocks of two competing unaligned AIOs can result in data
 229          * corruption.
 230          */
 231         if (o_direct && ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) &&
 232             !is_sync_kiocb(iocb) &&
 233             ext4_unaligned_aio(inode, from, iocb->ki_pos)) {
 234                 unaligned_aio = 1;
 235                 ext4_unwritten_wait(inode);
 236         }
 237
 238         iocb->private = &overwrite;
 239         /* Check whether we do a DIO overwrite or not */
 240         if (o_direct && ext4_should_dioread_nolock(inode) && !unaligned_aio &&
 241             ext4_overwrite_io(inode, iocb->ki_pos, iov_iter_count(from)))
 242                 overwrite = 1;
 243
 244         ret = __generic_file_write_iter(iocb, from);
 245         inode_unlock(inode);
 246
 247         if (ret > 0)
 248                 ret = generic_write_sync(iocb, ret);
 249
 250         return ret;
 251
 252 out:
 253         inode_unlock(inode);
 254         return ret;
 255 }
 256
 257 #ifdef CONFIG_FS_DAX
 258 static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 259 {
 260         int result;
 261         handle_t *handle = NULL;
 262         struct inode *inode = file_inode(vma->vm_file);
 263         struct super_block *sb = inode->i_sb;
 264         bool write = vmf->flags & FAULT_FLAG_WRITE;
 265
 266         if (write) {
 267                 sb_start_pagefault(sb);
 268                 file_update_time(vma->vm_file);
 269                 down_read(&EXT4_I(inode)->i_mmap_sem);
 270                 handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
 271                                                 EXT4_DATA_TRANS_BLOCKS(sb));
 272         } else
 273                 down_read(&EXT4_I(inode)->i_mmap_sem);
 274
 275         if (IS_ERR(handle))
 276                 result = VM_FAULT_SIGBUS;
 277         else
 278                 result = dax_iomap_fault(vma, vmf, &ext4_iomap_ops);
 279
 280         if (write) {
 281                 if (!IS_ERR(handle))
 282                         ext4_journal_stop(handle);
 283                 up_read(&EXT4_I(inode)->i_mmap_sem);
 284                 sb_end_pagefault(sb);
 285         } else
 286                 up_read(&EXT4_I(inode)->i_mmap_sem);
 287
 288         return result;
 289 }
 290
 291 static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
 292                                                 pmd_t *pmd, unsigned int flags)
 293 {
 294         int result;
 295         handle_t *handle = NULL;
 296         struct inode *inode = file_inode(vma->vm_file);
 297         struct super_block *sb = inode->i_sb;
 298         bool write = flags & FAULT_FLAG_WRITE;
 299
 300         if (write) {
 301                 sb_start_pagefault(sb);
 302                 file_update_time(vma->vm_file);
 303                 down_read(&EXT4_I(inode)->i_mmap_sem);
 304                 handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
 305                                 ext4_chunk_trans_blocks(inode,
 306                                                         PMD_SIZE / PAGE_SIZE));
 307         } else
 308                 down_read(&EXT4_I(inode)->i_mmap_sem);
 309
 310         if (IS_ERR(handle))
 311                 result = VM_FAULT_SIGBUS;
 312         else {
 313                 result = dax_iomap_pmd_fault(vma, addr, pmd, flags,
 314                                              &ext4_iomap_ops);
 315         }
 316
 317         if (write) {
 318                 if (!IS_ERR(handle))
 319                         ext4_journal_stop(handle);
 320                 up_read(&EXT4_I(inode)->i_mmap_sem);
 321                 sb_end_pagefault(sb);
 322         } else
 323                 up_read(&EXT4_I(inode)->i_mmap_sem);
 324
 325         return result;
 326 }
 327
 328 /*
 329  * Handle write fault for VM_MIXEDMAP mappings. Similarly to ext4_dax_fault()
 330  * handler we check for races agaist truncate. Note that since we cycle through
 331  * i_mmap_sem, we are sure that also any hole punching that began before we
 332  * were called is finished by now and so if it included part of the file we
 333  * are working on, our pte will get unmapped and the check for pte_same() in
 334  * wp_pfn_shared() fails. Thus fault gets retried and things work out as
 335  * desired.
 336  */
 337 static int ext4_dax_pfn_mkwrite(struct vm_area_struct *vma,
 338                                 struct vm_fault *vmf)
 339 {
 340         struct inode *inode = file_inode(vma->vm_file);
 341         struct super_block *sb = inode->i_sb;
 342         loff_t size;
 343         int ret;
 344
 345         sb_start_pagefault(sb);
 346         file_update_time(vma->vm_file);
 347         down_read(&EXT4_I(inode)->i_mmap_sem);
 348         size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
 349         if (vmf->pgoff >= size)
 350                 ret = VM_FAULT_SIGBUS;
 351         else
 352                 ret = dax_pfn_mkwrite(vma, vmf);
 353         up_read(&EXT4_I(inode)->i_mmap_sem);
 354         sb_end_pagefault(sb);
 355
 356         return ret;
 357 }
 358
 359 static const struct vm_operations_struct ext4_dax_vm_ops = {
 360         .fault          = ext4_dax_fault,
 361         .pmd_fault      = ext4_dax_pmd_fault,
 362         .page_mkwrite   = ext4_dax_fault,
 363         .pfn_mkwrite    = ext4_dax_pfn_mkwrite,
 364 };
 365 #else
 366 #define ext4_dax_vm_ops ext4_file_vm_ops
 367 #endif
 368
 369 static const struct vm_operations_struct ext4_file_vm_ops = {
 370         .fault          = ext4_filemap_fault,
 371         .map_pages      = filemap_map_pages,
 372         .page_mkwrite   = ext4_page_mkwrite,
 373 };
 374
 375 static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
 376 {
 377         struct inode *inode = file->f_mapping->host;
 378
 379         if (ext4_encrypted_inode(inode)) {
 380                 int err = fscrypt_get_encryption_info(inode);
 381                 if (err)
 382                         return 0;
 383                 if (!fscrypt_has_encryption_key(inode))
 384                         return -ENOKEY;
 385         }
 386         file_accessed(file);
 387         if (IS_DAX(file_inode(file))) {
 388                 vma->vm_ops = &ext4_dax_vm_ops;
 389                 vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;
 390         } else {
 391                 vma->vm_ops = &ext4_file_vm_ops;
 392         }
 393         return 0;
 394 }
 395
 396 static int ext4_file_open(struct inode * inode, struct file * filp)
 397 {
 398         struct super_block *sb = inode->i_sb;
 399         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 400         struct vfsmount *mnt = filp->f_path.mnt;
 401         struct dentry *dir;
 402         struct path path;
 403         char buf[64], *cp;
 404         int ret;
 405
 406         if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
 407                      !(sb->s_flags & MS_RDONLY))) {
 408                 sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
 409                 /*
 410                  * Sample where the filesystem has been mounted and
 411                  * store it in the superblock for sysadmin convenience
 412                  * when trying to sort through large numbers of block
 413                  * devices or filesystem images.
 414                  */
 415                 memset(buf, 0, sizeof(buf));
 416                 path.mnt = mnt;
 417                 path.dentry = mnt->mnt_root;
 418                 cp = d_path(&path, buf, sizeof(buf));
 419                 if (!IS_ERR(cp)) {
 420                         handle_t *handle;
 421                         int err;
 422
 423                         handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
 424                         if (IS_ERR(handle))
 425                                 return PTR_ERR(handle);
 426                         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
 427                         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
 428                         if (err) {
 429                                 ext4_journal_stop(handle);
 430                                 return err;
 431                         }
 432                         strlcpy(sbi->s_es->s_last_mounted, cp,
 433                                 sizeof(sbi->s_es->s_last_mounted));
 434                         ext4_handle_dirty_super(handle, sb);
 435                         ext4_journal_stop(handle);
 436                 }
 437         }
 438         if (ext4_encrypted_inode(inode)) {
 439                 ret = fscrypt_get_encryption_info(inode);
 440                 if (ret)
 441                         return -EACCES;
 442                 if (!fscrypt_has_encryption_key(inode))
 443                         return -ENOKEY;
 444         }
 445
 446         dir = dget_parent(file_dentry(filp));
 447         if (ext4_encrypted_inode(d_inode(dir)) &&
 448                         !fscrypt_has_permitted_context(d_inode(dir), inode)) {
 449                 ext4_warning(inode->i_sb,
 450                              "Inconsistent encryption contexts: %lu/%lu",
 451                              (unsigned long) d_inode(dir)->i_ino,
 452                              (unsigned long) inode->i_ino);
 453                 dput(dir);
 454                 return -EPERM;
 455         }
 456         dput(dir);
 457         /*
 458          * Set up the jbd2_inode if we are opening the inode for
 459          * writing and the journal is present
 460          */
 461         if (filp->f_mode & FMODE_WRITE) {
 462                 ret = ext4_inode_attach_jinode(inode);
 463                 if (ret < 0)
 464                         return ret;
 465         }
 466         return dquot_file_open(inode, filp);
 467 }
 468
 469 /*
 470  * Here we use ext4_map_blocks() to get a block mapping for a extent-based
 471  * file rather than ext4_ext_walk_space() because we can introduce
 472  * SEEK_DATA/SEEK_HOLE for block-mapped and extent-mapped file at the same
 473  * function.  When extent status tree has been fully implemented, it will
 474  * track all extent status for a file and we can directly use it to
 475  * retrieve the offset for SEEK_DATA/SEEK_HOLE.
 476  */
 477
 478 /*
 479  * When we retrieve the offset for SEEK_DATA/SEEK_HOLE, we would need to
 480  * lookup page cache to check whether or not there has some data between
 481  * [startoff, endoff] because, if this range contains an unwritten extent,
 482  * we determine this extent as a data or a hole according to whether the
 483  * page cache has data or not.
 484  */
 485 static int ext4_find_unwritten_pgoff(struct inode *inode,
 486                                      int whence,
 487                                      ext4_lblk_t end_blk,
 488                                      loff_t *offset)
 489 {
 490         struct pagevec pvec;
 491         unsigned int blkbits;
 492         pgoff_t index;
 493         pgoff_t end;
 494         loff_t endoff;
 495         loff_t startoff;
 496         loff_t lastoff;
 497         int found = 0;
 498
 499         blkbits = inode->i_sb->s_blocksize_bits;
 500         startoff = *offset;
 501         lastoff = startoff;
 502         endoff = (loff_t)end_blk << blkbits;
 503
 504         index = startoff >> PAGE_SHIFT;
 505         end = endoff >> PAGE_SHIFT;
 506
 507         pagevec_init(&pvec, 0);
 508         do {
 509                 int i, num;
 510                 unsigned long nr_pages;
 511
 512                 num = min_t(pgoff_t, end - index, PAGEVEC_SIZE);
 513                 nr_pages = pagevec_lookup(&pvec, inode->i_mapping, index,
 514                                           (pgoff_t)num);
 515                 if (nr_pages == 0) {
 516                         if (whence == SEEK_DATA)
 517                                 break;
 518
 519                         BUG_ON(whence != SEEK_HOLE);
 520                         /*
 521                          * If this is the first time to go into the loop and
 522                          * offset is not beyond the end offset, it will be a
 523                          * hole at this offset
 524                          */
 525                         if (lastoff == startoff || lastoff < endoff)
 526                                 found = 1;
 527                         break;
 528                 }
 529
 530                 /*
 531                  * If this is the first time to go into the loop and
 532                  * offset is smaller than the first page offset, it will be a
 533                  * hole at this offset.
 534                  */
 535                 if (lastoff == startoff && whence == SEEK_HOLE &&
 536                     lastoff < page_offset(pvec.pages[0])) {
 537                         found = 1;
 538                         break;
 539                 }
 540
 541                 for (i = 0; i < nr_pages; i++) {
 542                         struct page *page = pvec.pages[i];
 543                         struct buffer_head *bh, *head;
 544
 545                         /*
 546                          * If the current offset is not beyond the end of given
 547                          * range, it will be a hole.
 548                          */
 549                         if (lastoff < endoff && whence == SEEK_HOLE &&
 550                             page->index > end) {
 551                                 found = 1;
 552                                 *offset = lastoff;
 553                                 goto out;
 554                         }
 555
 556                         lock_page(page);
 557
 558                         if (unlikely(page->mapping != inode->i_mapping)) {
 559                                 unlock_page(page);
 560                                 continue;
 561                         }
 562
 563                         if (!page_has_buffers(page)) {
 564                                 unlock_page(page);
 565                                 continue;
 566                         }
 567
 568                         if (page_has_buffers(page)) {
 569                                 lastoff = page_offset(page);
 570                                 bh = head = page_buffers(page);
 571                                 do {
 572                                         if (buffer_uptodate(bh) ||
 573                                             buffer_unwritten(bh)) {
 574                                                 if (whence == SEEK_DATA)
 575                                                         found = 1;
 576                                         } else {
 577                                                 if (whence == SEEK_HOLE)
 578                                                         found = 1;
 579                                         }
 580                                         if (found) {
 581                                                 *offset = max_t(loff_t,
 582                                                         startoff, lastoff);
 583                                                 unlock_page(page);
 584                                                 goto out;
 585                                         }
 586                                         lastoff += bh->b_size;
 587                                         bh = bh->b_this_page;
 588                                 } while (bh != head);
 589                         }
 590
 591                         lastoff = page_offset(page) + PAGE_SIZE;
 592                         unlock_page(page);
 593                 }
 594
 595                 /*
 596                  * The no. of pages is less than our desired, that would be a
 597                  * hole in there.
 598                  */
 599                 if (nr_pages < num && whence == SEEK_HOLE) {
 600                         found = 1;
 601                         *offset = lastoff;
 602                         break;
 603                 }
 604
 605                 index = pvec.pages[i - 1]->index + 1;
 606                 pagevec_release(&pvec);
 607         } while (index <= end);
 608
 609 out:
 610         pagevec_release(&pvec);
 611         return found;
 612 }
 613
 614 /*
 615  * ext4_seek_data() retrieves the offset for SEEK_DATA.
 616  */
 617 static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize)
 618 {
 619         struct inode *inode = file->f_mapping->host;
 620         struct extent_status es;
 621         ext4_lblk_t start, last, end;
 622         loff_t dataoff, isize;
 623         int blkbits;
 624         int ret;
 625
 626         inode_lock(inode);
 627
 628         isize = i_size_read(inode);
 629         if (offset >= isize) {
 630                 inode_unlock(inode);
 631                 return -ENXIO;
 632         }
 633
 634         blkbits = inode->i_sb->s_blocksize_bits;
 635         start = offset >> blkbits;
 636         last = start;
 637         end = isize >> blkbits;
 638         dataoff = offset;
 639
 640         do {
 641                 ret = ext4_get_next_extent(inode, last, end - last + 1, &es);
 642                 if (ret <= 0) {
 643                         /* No extent found -> no data */
 644                         if (ret == 0)
 645                                 ret = -ENXIO;
 646                         inode_unlock(inode);
 647                         return ret;
 648                 }
 649
 650                 last = es.es_lblk;
 651                 if (last != start)
 652                         dataoff = (loff_t)last << blkbits;
 653                 if (!ext4_es_is_unwritten(&es))
 654                         break;
 655
 656                 /*
 657                  * If there is a unwritten extent at this offset,
 658                  * it will be as a data or a hole according to page
 659                  * cache that has data or not.
 660                  */
 661                 if (ext4_find_unwritten_pgoff(inode, SEEK_DATA,
 662                                               es.es_lblk + es.es_len, &dataoff))
 663                         break;
 664                 last += es.es_len;
 665                 dataoff = (loff_t)last << blkbits;
 666                 cond_resched();
 667         } while (last <= end);
 668
 669         inode_unlock(inode);
 670
 671         if (dataoff > isize)
 672                 return -ENXIO;
 673
 674         return vfs_setpos(file, dataoff, maxsize);
 675 }
 676
 677 /*
 678  * ext4_seek_hole() retrieves the offset for SEEK_HOLE.
 679  */
 680 static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize)
 681 {
 682         struct inode *inode = file->f_mapping->host;
 683         struct extent_status es;
 684         ext4_lblk_t start, last, end;
 685         loff_t holeoff, isize;
 686         int blkbits;
 687         int ret;
 688
 689         inode_lock(inode);
 690
 691         isize = i_size_read(inode);
 692         if (offset >= isize) {
 693                 inode_unlock(inode);
 694                 return -ENXIO;
 695         }
 696
 697         blkbits = inode->i_sb->s_blocksize_bits;
 698         start = offset >> blkbits;
 699         last = start;
 700         end = isize >> blkbits;
 701         holeoff = offset;
 702
 703         do {
 704                 ret = ext4_get_next_extent(inode, last, end - last + 1, &es);
 705                 if (ret < 0) {
 706                         inode_unlock(inode);
 707                         return ret;
 708                 }
 709                 /* Found a hole? */
 710                 if (ret == 0 || es.es_lblk > last) {
 711                         if (last != start)
 712                                 holeoff = (loff_t)last << blkbits;
 713                         break;
 714                 }
 715                 /*
 716                  * If there is a unwritten extent at this offset,
 717                  * it will be as a data or a hole according to page
 718                  * cache that has data or not.
 719                  */
 720                 if (ext4_es_is_unwritten(&es) &&
 721                     ext4_find_unwritten_pgoff(inode, SEEK_HOLE,
 722                                               last + es.es_len, &holeoff))
 723                         break;
 724
 725                 last += es.es_len;
 726                 holeoff = (loff_t)last << blkbits;
 727                 cond_resched();
 728         } while (last <= end);
 729
 730         inode_unlock(inode);
 731
 732         if (holeoff > isize)
 733                 holeoff = isize;
 734
 735         return vfs_setpos(file, holeoff, maxsize);
 736 }
 737
 738 /*
 739  * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
 740  * by calling generic_file_llseek_size() with the appropriate maxbytes
 741  * value for each.
 742  */
 743 loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
 744 {
 745         struct inode *inode = file->f_mapping->host;
 746         loff_t maxbytes;
 747
 748         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 749                 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
 750         else
 751                 maxbytes = inode->i_sb->s_maxbytes;
 752
 753         switch (whence) {
 754         case SEEK_SET:
 755         case SEEK_CUR:
 756         case SEEK_END:
 757                 return generic_file_llseek_size(file, offset, whence,
 758                                                 maxbytes, i_size_read(inode));
 759         case SEEK_DATA:
 760                 return ext4_seek_data(file, offset, maxbytes);
 761         case SEEK_HOLE:
 762                 return ext4_seek_hole(file, offset, maxbytes);
 763         }
 764
 765         return -EINVAL;
 766 }
 767
 768 const struct file_operations ext4_file_operations = {
 769         .llseek         = ext4_llseek,
 770         .read_iter      = ext4_file_read_iter,
 771         .write_iter     = ext4_file_write_iter,
 772         .unlocked_ioctl = ext4_ioctl,
 773 #ifdef CONFIG_COMPAT
 774         .compat_ioctl   = ext4_compat_ioctl,
 775 #endif
 776         .mmap           = ext4_file_mmap,
 777         .open           = ext4_file_open,
 778         .release        = ext4_release_file,
 779         .fsync          = ext4_sync_file,
 780         .get_unmapped_area = thp_get_unmapped_area,
 781         .splice_read    = generic_file_splice_read,
 782         .splice_write   = iter_file_splice_write,
 783         .fallocate      = ext4_fallocate,
 784 };
 785
 786 const struct inode_operations ext4_file_inode_operations = {
 787         .setattr        = ext4_setattr,
 788         .getattr        = ext4_getattr,
 789         .listxattr      = ext4_listxattr,
 790         .get_acl        = ext4_get_acl,
 791         .set_acl        = ext4_set_acl,
 792         .fiemap         = ext4_fiemap,
 793 };
 794