]> git.ipfire.org Git - thirdparty/kernel/linux.git/commitdiff
ntfs: update iomap and address space operations
authorNamjae Jeon <linkinjeon@kernel.org>
Fri, 13 Feb 2026 01:42:29 +0000 (10:42 +0900)
committerNamjae Jeon <linkinjeon@kernel.org>
Thu, 19 Feb 2026 12:50:48 +0000 (21:50 +0900)
Update the address space operations to use the iomap framework,
replacing legacy buffer-head based code.

Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
fs/ntfs/aops.c
fs/ntfs/iomap.c [new file with mode: 0644]

index 2d01517a2d59af153a235a9263545a63bb61c1ee..01ed11f5689083199894ac0094ad70bb3f1bd8bb 100644 (file)
 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
- * aops.c - NTFS kernel address space operations and page cache handling.
+ * NTFS kernel address space operations and page cache handling.
  *
  * Copyright (c) 2001-2014 Anton Altaparmakov and Tuxera Inc.
  * Copyright (c) 2002 Richard Russon
+ * Copyright (c) 2025 LG Electronics Co., Ltd.
  */
 
-#include <linux/errno.h>
-#include <linux/fs.h>
-#include <linux/gfp.h>
-#include <linux/mm.h>
-#include <linux/pagemap.h>
-#include <linux/swap.h>
-#include <linux/buffer_head.h>
 #include <linux/writeback.h>
-#include <linux/bit_spinlock.h>
-#include <linux/bio.h>
 
-#include "aops.h"
 #include "attrib.h"
-#include "debug.h"
-#include "inode.h"
 #include "mft.h"
-#include "runlist.h"
-#include "types.h"
 #include "ntfs.h"
+#include "debug.h"
+#include "iomap.h"
 
-/**
- * ntfs_end_buffer_async_read - async io completion for reading attributes
- * @bh:                buffer head on which io is completed
- * @uptodate:  whether @bh is now uptodate or not
- *
- * Asynchronous I/O completion handler for reading pages belonging to the
- * attribute address space of an inode.  The inodes can either be files or
- * directories or they can be fake inodes describing some attribute.
- *
- * If NInoMstProtected(), perform the post read mst fixups when all IO on the
- * page has been completed and mark the page uptodate or set the error bit on
- * the page.  To determine the size of the records that need fixing up, we
- * cheat a little bit by setting the index_block_size in ntfs_inode to the ntfs
- * record size, and index_block_size_bits, to the log(base 2) of the ntfs
- * record size.
- */
-static void ntfs_end_buffer_async_read(struct buffer_head *bh, int uptodate)
-{
-       unsigned long flags;
-       struct buffer_head *first, *tmp;
-       struct page *page;
-       struct inode *vi;
-       ntfs_inode *ni;
-       int page_uptodate = 1;
-
-       page = bh->b_page;
-       vi = page->mapping->host;
-       ni = NTFS_I(vi);
-
-       if (likely(uptodate)) {
-               loff_t i_size;
-               s64 file_ofs, init_size;
-
-               set_buffer_uptodate(bh);
-
-               file_ofs = ((s64)page->index << PAGE_SHIFT) +
-                               bh_offset(bh);
-               read_lock_irqsave(&ni->size_lock, flags);
-               init_size = ni->initialized_size;
-               i_size = i_size_read(vi);
-               read_unlock_irqrestore(&ni->size_lock, flags);
-               if (unlikely(init_size > i_size)) {
-                       /* Race with shrinking truncate. */
-                       init_size = i_size;
-               }
-               /* Check for the current buffer head overflowing. */
-               if (unlikely(file_ofs + bh->b_size > init_size)) {
-                       int ofs;
-                       void *kaddr;
-
-                       ofs = 0;
-                       if (file_ofs < init_size)
-                               ofs = init_size - file_ofs;
-                       kaddr = kmap_atomic(page);
-                       memset(kaddr + bh_offset(bh) + ofs, 0,
-                                       bh->b_size - ofs);
-                       flush_dcache_page(page);
-                       kunmap_atomic(kaddr);
-               }
-       } else {
-               clear_buffer_uptodate(bh);
-               SetPageError(page);
-               ntfs_error(ni->vol->sb, "Buffer I/O error, logical block "
-                               "0x%llx.", (unsigned long long)bh->b_blocknr);
-       }
-       first = page_buffers(page);
-       spin_lock_irqsave(&first->b_uptodate_lock, flags);
-       clear_buffer_async_read(bh);
-       unlock_buffer(bh);
-       tmp = bh;
-       do {
-               if (!buffer_uptodate(tmp))
-                       page_uptodate = 0;
-               if (buffer_async_read(tmp)) {
-                       if (likely(buffer_locked(tmp)))
-                               goto still_busy;
-                       /* Async buffers must be locked. */
-                       BUG();
-               }
-               tmp = tmp->b_this_page;
-       } while (tmp != bh);
-       spin_unlock_irqrestore(&first->b_uptodate_lock, flags);
-       /*
-        * If none of the buffers had errors then we can set the page uptodate,
-        * but we first have to perform the post read mst fixups, if the
-        * attribute is mst protected, i.e. if NInoMstProteced(ni) is true.
-        * Note we ignore fixup errors as those are detected when
-        * map_mft_record() is called which gives us per record granularity
-        * rather than per page granularity.
-        */
-       if (!NInoMstProtected(ni)) {
-               if (likely(page_uptodate && !PageError(page)))
-                       SetPageUptodate(page);
-       } else {
-               u8 *kaddr;
-               unsigned int i, recs;
-               u32 rec_size;
-
-               rec_size = ni->itype.index.block_size;
-               recs = PAGE_SIZE / rec_size;
-               /* Should have been verified before we got here... */
-               BUG_ON(!recs);
-               kaddr = kmap_atomic(page);
-               for (i = 0; i < recs; i++)
-                       post_read_mst_fixup((NTFS_RECORD*)(kaddr +
-                                       i * rec_size), rec_size);
-               kunmap_atomic(kaddr);
-               flush_dcache_page(page);
-               if (likely(page_uptodate && !PageError(page)))
-                       SetPageUptodate(page);
-       }
-       unlock_page(page);
-       return;
-still_busy:
-       spin_unlock_irqrestore(&first->b_uptodate_lock, flags);
-       return;
-}
-
-/**
- * ntfs_read_block - fill a @folio of an address space with data
- * @folio:     page cache folio to fill with data
- *
- * We read each buffer asynchronously and when all buffers are read in, our io
- * completion handler ntfs_end_buffer_read_async(), if required, automatically
- * applies the mst fixups to the folio before finally marking it uptodate and
- * unlocking it.
- *
- * We only enforce allocated_size limit because i_size is checked for in
- * generic_file_read().
- *
- * Return 0 on success and -errno on error.
- *
- * Contains an adapted version of fs/buffer.c::block_read_full_folio().
- */
-static int ntfs_read_block(struct folio *folio)
-{
-       loff_t i_size;
-       VCN vcn;
-       LCN lcn;
-       s64 init_size;
-       struct inode *vi;
-       ntfs_inode *ni;
-       ntfs_volume *vol;
-       runlist_element *rl;
-       struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
-       sector_t iblock, lblock, zblock;
-       unsigned long flags;
-       unsigned int blocksize, vcn_ofs;
-       int i, nr;
-       unsigned char blocksize_bits;
-
-       vi = folio->mapping->host;
-       ni = NTFS_I(vi);
-       vol = ni->vol;
-
-       /* $MFT/$DATA must have its complete runlist in memory at all times. */
-       BUG_ON(!ni->runlist.rl && !ni->mft_no && !NInoAttr(ni));
-
-       blocksize = vol->sb->s_blocksize;
-       blocksize_bits = vol->sb->s_blocksize_bits;
-
-       head = folio_buffers(folio);
-       if (!head)
-               head = create_empty_buffers(folio, blocksize, 0);
-       bh = head;
-
-       /*
-        * We may be racing with truncate.  To avoid some of the problems we
-        * now take a snapshot of the various sizes and use those for the whole
-        * of the function.  In case of an extending truncate it just means we
-        * may leave some buffers unmapped which are now allocated.  This is
-        * not a problem since these buffers will just get mapped when a write
-        * occurs.  In case of a shrinking truncate, we will detect this later
-        * on due to the runlist being incomplete and if the folio is being
-        * fully truncated, truncate will throw it away as soon as we unlock
-        * it so no need to worry what we do with it.
-        */
-       iblock = (s64)folio->index << (PAGE_SHIFT - blocksize_bits);
-       read_lock_irqsave(&ni->size_lock, flags);
-       lblock = (ni->allocated_size + blocksize - 1) >> blocksize_bits;
-       init_size = ni->initialized_size;
-       i_size = i_size_read(vi);
-       read_unlock_irqrestore(&ni->size_lock, flags);
-       if (unlikely(init_size > i_size)) {
-               /* Race with shrinking truncate. */
-               init_size = i_size;
-       }
-       zblock = (init_size + blocksize - 1) >> blocksize_bits;
-
-       /* Loop through all the buffers in the folio. */
-       rl = NULL;
-       nr = i = 0;
-       do {
-               int err = 0;
-
-               if (unlikely(buffer_uptodate(bh)))
-                       continue;
-               if (unlikely(buffer_mapped(bh))) {
-                       arr[nr++] = bh;
-                       continue;
-               }
-               bh->b_bdev = vol->sb->s_bdev;
-               /* Is the block within the allowed limits? */
-               if (iblock < lblock) {
-                       bool is_retry = false;
-
-                       /* Convert iblock into corresponding vcn and offset. */
-                       vcn = (VCN)iblock << blocksize_bits >>
-                                       vol->cluster_size_bits;
-                       vcn_ofs = ((VCN)iblock << blocksize_bits) &
-                                       vol->cluster_size_mask;
-                       if (!rl) {
-lock_retry_remap:
-                               down_read(&ni->runlist.lock);
-                               rl = ni->runlist.rl;
-                       }
-                       if (likely(rl != NULL)) {
-                               /* Seek to element containing target vcn. */
-                               while (rl->length && rl[1].vcn <= vcn)
-                                       rl++;
-                               lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
-                       } else
-                               lcn = LCN_RL_NOT_MAPPED;
-                       /* Successful remap. */
-                       if (lcn >= 0) {
-                               /* Setup buffer head to correct block. */
-                               bh->b_blocknr = ((lcn << vol->cluster_size_bits)
-                                               + vcn_ofs) >> blocksize_bits;
-                               set_buffer_mapped(bh);
-                               /* Only read initialized data blocks. */
-                               if (iblock < zblock) {
-                                       arr[nr++] = bh;
-                                       continue;
-                               }
-                               /* Fully non-initialized data block, zero it. */
-                               goto handle_zblock;
-                       }
-                       /* It is a hole, need to zero it. */
-                       if (lcn == LCN_HOLE)
-                               goto handle_hole;
-                       /* If first try and runlist unmapped, map and retry. */
-                       if (!is_retry && lcn == LCN_RL_NOT_MAPPED) {
-                               is_retry = true;
-                               /*
-                                * Attempt to map runlist, dropping lock for
-                                * the duration.
-                                */
-                               up_read(&ni->runlist.lock);
-                               err = ntfs_map_runlist(ni, vcn);
-                               if (likely(!err))
-                                       goto lock_retry_remap;
-                               rl = NULL;
-                       } else if (!rl)
-                               up_read(&ni->runlist.lock);
-                       /*
-                        * If buffer is outside the runlist, treat it as a
-                        * hole.  This can happen due to concurrent truncate
-                        * for example.
-                        */
-                       if (err == -ENOENT || lcn == LCN_ENOENT) {
-                               err = 0;
-                               goto handle_hole;
-                       }
-                       /* Hard error, zero out region. */
-                       if (!err)
-                               err = -EIO;
-                       bh->b_blocknr = -1;
-                       folio_set_error(folio);
-                       ntfs_error(vol->sb, "Failed to read from inode 0x%lx, "
-                                       "attribute type 0x%x, vcn 0x%llx, "
-                                       "offset 0x%x because its location on "
-                                       "disk could not be determined%s "
-                                       "(error code %i).", ni->mft_no,
-                                       ni->type, (unsigned long long)vcn,
-                                       vcn_ofs, is_retry ? " even after "
-                                       "retrying" : "", err);
-               }
-               /*
-                * Either iblock was outside lblock limits or
-                * ntfs_rl_vcn_to_lcn() returned error.  Just zero that portion
-                * of the folio and set the buffer uptodate.
-                */
-handle_hole:
-               bh->b_blocknr = -1UL;
-               clear_buffer_mapped(bh);
-handle_zblock:
-               folio_zero_range(folio, i * blocksize, blocksize);
-               if (likely(!err))
-                       set_buffer_uptodate(bh);
-       } while (i++, iblock++, (bh = bh->b_this_page) != head);
-
-       /* Release the lock if we took it. */
-       if (rl)
-               up_read(&ni->runlist.lock);
-
-       /* Check we have at least one buffer ready for i/o. */
-       if (nr) {
-               struct buffer_head *tbh;
-
-               /* Lock the buffers. */
-               for (i = 0; i < nr; i++) {
-                       tbh = arr[i];
-                       lock_buffer(tbh);
-                       tbh->b_end_io = ntfs_end_buffer_async_read;
-                       set_buffer_async_read(tbh);
-               }
-               /* Finally, start i/o on the buffers. */
-               for (i = 0; i < nr; i++) {
-                       tbh = arr[i];
-                       if (likely(!buffer_uptodate(tbh)))
-                               submit_bh(REQ_OP_READ, tbh);
-                       else
-                               ntfs_end_buffer_async_read(tbh, 1);
-               }
-               return 0;
-       }
-       /* No i/o was scheduled on any of the buffers. */
-       if (likely(!folio_test_error(folio)))
-               folio_mark_uptodate(folio);
-       else /* Signal synchronous i/o error. */
-               nr = -EIO;
-       folio_unlock(folio);
-       return nr;
-}
-
-/**
- * ntfs_read_folio - fill a @folio of a @file with data from the device
+/*
+ * ntfs_read_folio - Read data for a folio from the device
  * @file:      open file to which the folio @folio belongs or NULL
  * @folio:     page cache folio to fill with data
  *
- * For non-resident attributes, ntfs_read_folio() fills the @folio of the open
- * file @file by calling the ntfs version of the generic block_read_full_folio()
- * function, ntfs_read_block(), which in turn creates and reads in the buffers
- * associated with the folio asynchronously.
+ * This function handles reading data into the page cache. It first checks
+ * for specific ntfs attribute type like encryption and compression.
  *
- * For resident attributes, OTOH, ntfs_read_folio() fills @folio by copying the
- * data from the mft record (which at this stage is most likely in memory) and
- * fills the remainder with zeroes. Thus, in this case, I/O is synchronous, as
- * even if the mft record is not cached at this point in time, we need to wait
- * for it to be read in before we can do the copy.
+ * - If the attribute is encrypted, access is denied (-EACCES) because
+ *   decryption is not supported in this path.
+ * - If the attribute is non-resident and compressed, the read operation is
+ *   delegated to ntfs_read_compressed_block().
+ * - For normal resident or non-resident attribute, it utilizes the generic
+ *   iomap infrastructure via iomap_bio_read_folio() to perform the I/O.
  *
- * Return 0 on success and -errno on error.
+ * Return: 0 on success, or -errno on error.
  */
 static int ntfs_read_folio(struct file *file, struct folio *folio)
 {
-       struct page *page = &folio->page;
-       loff_t i_size;
-       struct inode *vi;
-       ntfs_inode *ni, *base_ni;
-       u8 *addr;
-       ntfs_attr_search_ctx *ctx;
-       MFT_RECORD *mrec;
-       unsigned long flags;
-       u32 attr_len;
-       int err = 0;
+       struct ntfs_inode *ni = NTFS_I(folio->mapping->host);
 
-retry_readpage:
-       BUG_ON(!PageLocked(page));
-       vi = page->mapping->host;
-       i_size = i_size_read(vi);
-       /* Is the page fully outside i_size? (truncate in progress) */
-       if (unlikely(page->index >= (i_size + PAGE_SIZE - 1) >>
-                       PAGE_SHIFT)) {
-               zero_user(page, 0, PAGE_SIZE);
-               ntfs_debug("Read outside i_size - truncated?");
-               goto done;
-       }
-       /*
-        * This can potentially happen because we clear PageUptodate() during
-        * ntfs_writepage() of MstProtected() attributes.
-        */
-       if (PageUptodate(page)) {
-               unlock_page(page);
-               return 0;
-       }
-       ni = NTFS_I(vi);
        /*
         * Only $DATA attributes can be encrypted and only unnamed $DATA
         * attributes can be compressed.  Index root can have the flags set but
@@ -411,1102 +45,24 @@ retry_readpage:
         * index inodes.
         */
        if (ni->type != AT_INDEX_ALLOCATION) {
-               /* If attribute is encrypted, deny access, just like NT4. */
-               if (NInoEncrypted(ni)) {
-                       BUG_ON(ni->type != AT_DATA);
-                       err = -EACCES;
-                       goto err_out;
-               }
-               /* Compressed data streams are handled in compress.c. */
-               if (NInoNonResident(ni) && NInoCompressed(ni)) {
-                       BUG_ON(ni->type != AT_DATA);
-                       BUG_ON(ni->name_len);
-                       return ntfs_read_compressed_block(page);
-               }
-       }
-       /* NInoNonResident() == NInoIndexAllocPresent() */
-       if (NInoNonResident(ni)) {
-               /* Normal, non-resident data stream. */
-               return ntfs_read_block(folio);
-       }
-       /*
-        * Attribute is resident, implying it is not compressed or encrypted.
-        * This also means the attribute is smaller than an mft record and
-        * hence smaller than a page, so can simply zero out any pages with
-        * index above 0.  Note the attribute can actually be marked compressed
-        * but if it is resident the actual data is not compressed so we are
-        * ok to ignore the compressed flag here.
-        */
-       if (unlikely(page->index > 0)) {
-               zero_user(page, 0, PAGE_SIZE);
-               goto done;
-       }
-       if (!NInoAttr(ni))
-               base_ni = ni;
-       else
-               base_ni = ni->ext.base_ntfs_ino;
-       /* Map, pin, and lock the mft record. */
-       mrec = map_mft_record(base_ni);
-       if (IS_ERR(mrec)) {
-               err = PTR_ERR(mrec);
-               goto err_out;
-       }
-       /*
-        * If a parallel write made the attribute non-resident, drop the mft
-        * record and retry the read_folio.
-        */
-       if (unlikely(NInoNonResident(ni))) {
-               unmap_mft_record(base_ni);
-               goto retry_readpage;
-       }
-       ctx = ntfs_attr_get_search_ctx(base_ni, mrec);
-       if (unlikely(!ctx)) {
-               err = -ENOMEM;
-               goto unm_err_out;
-       }
-       err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
-                       CASE_SENSITIVE, 0, NULL, 0, ctx);
-       if (unlikely(err))
-               goto put_unm_err_out;
-       attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
-       read_lock_irqsave(&ni->size_lock, flags);
-       if (unlikely(attr_len > ni->initialized_size))
-               attr_len = ni->initialized_size;
-       i_size = i_size_read(vi);
-       read_unlock_irqrestore(&ni->size_lock, flags);
-       if (unlikely(attr_len > i_size)) {
-               /* Race with shrinking truncate. */
-               attr_len = i_size;
-       }
-       addr = kmap_atomic(page);
-       /* Copy the data to the page. */
-       memcpy(addr, (u8*)ctx->attr +
-                       le16_to_cpu(ctx->attr->data.resident.value_offset),
-                       attr_len);
-       /* Zero the remainder of the page. */
-       memset(addr + attr_len, 0, PAGE_SIZE - attr_len);
-       flush_dcache_page(page);
-       kunmap_atomic(addr);
-put_unm_err_out:
-       ntfs_attr_put_search_ctx(ctx);
-unm_err_out:
-       unmap_mft_record(base_ni);
-done:
-       SetPageUptodate(page);
-err_out:
-       unlock_page(page);
-       return err;
-}
-
-#ifdef NTFS_RW
-
-/**
- * ntfs_write_block - write a @folio to the backing store
- * @folio:     page cache folio to write out
- * @wbc:       writeback control structure
- *
- * This function is for writing folios belonging to non-resident, non-mst
- * protected attributes to their backing store.
- *
- * For a folio with buffers, map and write the dirty buffers asynchronously
- * under folio writeback. For a folio without buffers, create buffers for the
- * folio, then proceed as above.
- *
- * If a folio doesn't have buffers the folio dirty state is definitive. If
- * a folio does have buffers, the folio dirty state is just a hint,
- * and the buffer dirty state is definitive. (A hint which has rules:
- * dirty buffers against a clean folio is illegal. Other combinations are
- * legal and need to be handled. In particular a dirty folio containing
- * clean buffers for example.)
- *
- * Return 0 on success and -errno on error.
- *
- * Based on ntfs_read_block() and __block_write_full_folio().
- */
-static int ntfs_write_block(struct folio *folio, struct writeback_control *wbc)
-{
-       VCN vcn;
-       LCN lcn;
-       s64 initialized_size;
-       loff_t i_size;
-       sector_t block, dblock, iblock;
-       struct inode *vi;
-       ntfs_inode *ni;
-       ntfs_volume *vol;
-       runlist_element *rl;
-       struct buffer_head *bh, *head;
-       unsigned long flags;
-       unsigned int blocksize, vcn_ofs;
-       int err;
-       bool need_end_writeback;
-       unsigned char blocksize_bits;
-
-       vi = folio->mapping->host;
-       ni = NTFS_I(vi);
-       vol = ni->vol;
-
-       ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
-                       "0x%lx.", ni->mft_no, ni->type, folio->index);
-
-       BUG_ON(!NInoNonResident(ni));
-       BUG_ON(NInoMstProtected(ni));
-       blocksize = vol->sb->s_blocksize;
-       blocksize_bits = vol->sb->s_blocksize_bits;
-       head = folio_buffers(folio);
-       if (!head) {
-               BUG_ON(!folio_test_uptodate(folio));
-               head = create_empty_buffers(folio, blocksize,
-                               (1 << BH_Uptodate) | (1 << BH_Dirty));
-       }
-       bh = head;
-
-       /* NOTE: Different naming scheme to ntfs_read_block()! */
-
-       /* The first block in the folio. */
-       block = (s64)folio->index << (PAGE_SHIFT - blocksize_bits);
-
-       read_lock_irqsave(&ni->size_lock, flags);
-       i_size = i_size_read(vi);
-       initialized_size = ni->initialized_size;
-       read_unlock_irqrestore(&ni->size_lock, flags);
-
-       /* The first out of bounds block for the data size. */
-       dblock = (i_size + blocksize - 1) >> blocksize_bits;
-
-       /* The last (fully or partially) initialized block. */
-       iblock = initialized_size >> blocksize_bits;
-
-       /*
-        * Be very careful.  We have no exclusion from block_dirty_folio
-        * here, and the (potentially unmapped) buffers may become dirty at
-        * any time.  If a buffer becomes dirty here after we've inspected it
-        * then we just miss that fact, and the folio stays dirty.
-        *
-        * Buffers outside i_size may be dirtied by block_dirty_folio;
-        * handle that here by just cleaning them.
-        */
-
-       /*
-        * Loop through all the buffers in the folio, mapping all the dirty
-        * buffers to disk addresses and handling any aliases from the
-        * underlying block device's mapping.
-        */
-       rl = NULL;
-       err = 0;
-       do {
-               bool is_retry = false;
-
-               if (unlikely(block >= dblock)) {
-                       /*
-                        * Mapped buffers outside i_size will occur, because
-                        * this folio can be outside i_size when there is a
-                        * truncate in progress. The contents of such buffers
-                        * were zeroed by ntfs_writepage().
-                        *
-                        * FIXME: What about the small race window where
-                        * ntfs_writepage() has not done any clearing because
-                        * the folio was within i_size but before we get here,
-                        * vmtruncate() modifies i_size?
-                        */
-                       clear_buffer_dirty(bh);
-                       set_buffer_uptodate(bh);
-                       continue;
-               }
-
-               /* Clean buffers are not written out, so no need to map them. */
-               if (!buffer_dirty(bh))
-                       continue;
-
-               /* Make sure we have enough initialized size. */
-               if (unlikely((block >= iblock) &&
-                               (initialized_size < i_size))) {
-                       /*
-                        * If this folio is fully outside initialized
-                        * size, zero out all folios between the current
-                        * initialized size and the current folio. Just
-                        * use ntfs_read_folio() to do the zeroing
-                        * transparently.
-                        */
-                       if (block > iblock) {
-                               // TODO:
-                               // For each folio do:
-                               // - read_cache_folio()
-                               // Again for each folio do:
-                               // - wait_on_folio_locked()
-                               // - Check (folio_test_uptodate(folio) &&
-                               //              !folio_test_error(folio))
-                               // Update initialized size in the attribute and
-                               // in the inode.
-                               // Again, for each folio do:
-                               //      block_dirty_folio();
-                               // folio_put()
-                               // We don't need to wait on the writes.
-                               // Update iblock.
-                       }
-                       /*
-                        * The current folio straddles initialized size. Zero
-                        * all non-uptodate buffers and set them uptodate (and
-                        * dirty?). Note, there aren't any non-uptodate buffers
-                        * if the folio is uptodate.
-                        * FIXME: For an uptodate folio, the buffers may need to
-                        * be written out because they were not initialized on
-                        * disk before.
-                        */
-                       if (!folio_test_uptodate(folio)) {
-                               // TODO:
-                               // Zero any non-uptodate buffers up to i_size.
-                               // Set them uptodate and dirty.
-                       }
-                       // TODO:
-                       // Update initialized size in the attribute and in the
-                       // inode (up to i_size).
-                       // Update iblock.
-                       // FIXME: This is inefficient. Try to batch the two
-                       // size changes to happen in one go.
-                       ntfs_error(vol->sb, "Writing beyond initialized size "
-                                       "is not supported yet. Sorry.");
-                       err = -EOPNOTSUPP;
-                       break;
-                       // Do NOT set_buffer_new() BUT DO clear buffer range
-                       // outside write request range.
-                       // set_buffer_uptodate() on complete buffers as well as
-                       // set_buffer_dirty().
-               }
-
-               /* No need to map buffers that are already mapped. */
-               if (buffer_mapped(bh))
-                       continue;
-
-               /* Unmapped, dirty buffer. Need to map it. */
-               bh->b_bdev = vol->sb->s_bdev;
-
-               /* Convert block into corresponding vcn and offset. */
-               vcn = (VCN)block << blocksize_bits;
-               vcn_ofs = vcn & vol->cluster_size_mask;
-               vcn >>= vol->cluster_size_bits;
-               if (!rl) {
-lock_retry_remap:
-                       down_read(&ni->runlist.lock);
-                       rl = ni->runlist.rl;
-               }
-               if (likely(rl != NULL)) {
-                       /* Seek to element containing target vcn. */
-                       while (rl->length && rl[1].vcn <= vcn)
-                               rl++;
-                       lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
-               } else
-                       lcn = LCN_RL_NOT_MAPPED;
-               /* Successful remap. */
-               if (lcn >= 0) {
-                       /* Setup buffer head to point to correct block. */
-                       bh->b_blocknr = ((lcn << vol->cluster_size_bits) +
-                                       vcn_ofs) >> blocksize_bits;
-                       set_buffer_mapped(bh);
-                       continue;
-               }
-               /* It is a hole, need to instantiate it. */
-               if (lcn == LCN_HOLE) {
-                       u8 *kaddr;
-                       unsigned long *bpos, *bend;
-
-                       /* Check if the buffer is zero. */
-                       kaddr = kmap_local_folio(folio, bh_offset(bh));
-                       bpos = (unsigned long *)kaddr;
-                       bend = (unsigned long *)(kaddr + blocksize);
-                       do {
-                               if (unlikely(*bpos))
-                                       break;
-                       } while (likely(++bpos < bend));
-                       kunmap_local(kaddr);
-                       if (bpos == bend) {
-                               /*
-                                * Buffer is zero and sparse, no need to write
-                                * it.
-                                */
-                               bh->b_blocknr = -1;
-                               clear_buffer_dirty(bh);
-                               continue;
-                       }
-                       // TODO: Instantiate the hole.
-                       // clear_buffer_new(bh);
-                       // clean_bdev_bh_alias(bh);
-                       ntfs_error(vol->sb, "Writing into sparse regions is "
-                                       "not supported yet. Sorry.");
-                       err = -EOPNOTSUPP;
-                       break;
-               }
-               /* If first try and runlist unmapped, map and retry. */
-               if (!is_retry && lcn == LCN_RL_NOT_MAPPED) {
-                       is_retry = true;
-                       /*
-                        * Attempt to map runlist, dropping lock for
-                        * the duration.
-                        */
-                       up_read(&ni->runlist.lock);
-                       err = ntfs_map_runlist(ni, vcn);
-                       if (likely(!err))
-                               goto lock_retry_remap;
-                       rl = NULL;
-               } else if (!rl)
-                       up_read(&ni->runlist.lock);
                /*
-                * If buffer is outside the runlist, truncate has cut it out
-                * of the runlist.  Just clean and clear the buffer and set it
-                * uptodate so it can get discarded by the VM.
+                * EFS-encrypted files are not supported.
+                * (decryption/encryption is not implemented yet)
                 */
-               if (err == -ENOENT || lcn == LCN_ENOENT) {
-                       bh->b_blocknr = -1;
-                       clear_buffer_dirty(bh);
-                       folio_zero_range(folio, bh_offset(bh), blocksize);
-                       set_buffer_uptodate(bh);
-                       err = 0;
-                       continue;
-               }
-               /* Failed to map the buffer, even after retrying. */
-               if (!err)
-                       err = -EIO;
-               bh->b_blocknr = -1;
-               ntfs_error(vol->sb, "Failed to write to inode 0x%lx, "
-                               "attribute type 0x%x, vcn 0x%llx, offset 0x%x "
-                               "because its location on disk could not be "
-                               "determined%s (error code %i).", ni->mft_no,
-                               ni->type, (unsigned long long)vcn,
-                               vcn_ofs, is_retry ? " even after "
-                               "retrying" : "", err);
-               break;
-       } while (block++, (bh = bh->b_this_page) != head);
-
-       /* Release the lock if we took it. */
-       if (rl)
-               up_read(&ni->runlist.lock);
-
-       /* For the error case, need to reset bh to the beginning. */
-       bh = head;
-
-       /* Just an optimization, so ->read_folio() is not called later. */
-       if (unlikely(!folio_test_uptodate(folio))) {
-               int uptodate = 1;
-               do {
-                       if (!buffer_uptodate(bh)) {
-                               uptodate = 0;
-                               bh = head;
-                               break;
-                       }
-               } while ((bh = bh->b_this_page) != head);
-               if (uptodate)
-                       folio_mark_uptodate(folio);
-       }
-
-       /* Setup all mapped, dirty buffers for async write i/o. */
-       do {
-               if (buffer_mapped(bh) && buffer_dirty(bh)) {
-                       lock_buffer(bh);
-                       if (test_clear_buffer_dirty(bh)) {
-                               BUG_ON(!buffer_uptodate(bh));
-                               mark_buffer_async_write(bh);
-                       } else
-                               unlock_buffer(bh);
-               } else if (unlikely(err)) {
-                       /*
-                        * For the error case. The buffer may have been set
-                        * dirty during attachment to a dirty folio.
-                        */
-                       if (err != -ENOMEM)
-                               clear_buffer_dirty(bh);
-               }
-       } while ((bh = bh->b_this_page) != head);
-
-       if (unlikely(err)) {
-               // TODO: Remove the -EOPNOTSUPP check later on...
-               if (unlikely(err == -EOPNOTSUPP))
-                       err = 0;
-               else if (err == -ENOMEM) {
-                       ntfs_warning(vol->sb, "Error allocating memory. "
-                                       "Redirtying folio so we try again "
-                                       "later.");
-                       /*
-                        * Put the folio back on mapping->dirty_pages, but
-                        * leave its buffer's dirty state as-is.
-                        */
-                       folio_redirty_for_writepage(wbc, folio);
-                       err = 0;
-               } else
-                       folio_set_error(folio);
-       }
-
-       BUG_ON(folio_test_writeback(folio));
-       folio_start_writeback(folio);   /* Keeps try_to_free_buffers() away. */
-
-       /* Submit the prepared buffers for i/o. */
-       need_end_writeback = true;
-       do {
-               struct buffer_head *next = bh->b_this_page;
-               if (buffer_async_write(bh)) {
-                       submit_bh(REQ_OP_WRITE, bh);
-                       need_end_writeback = false;
-               }
-               bh = next;
-       } while (bh != head);
-       folio_unlock(folio);
-
-       /* If no i/o was started, need to end writeback here. */
-       if (unlikely(need_end_writeback))
-               folio_end_writeback(folio);
-
-       ntfs_debug("Done.");
-       return err;
-}
-
-/**
- * ntfs_write_mst_block - write a @page to the backing store
- * @page:      page cache page to write out
- * @wbc:       writeback control structure
- *
- * This function is for writing pages belonging to non-resident, mst protected
- * attributes to their backing store.  The only supported attributes are index
- * allocation and $MFT/$DATA.  Both directory inodes and index inodes are
- * supported for the index allocation case.
- *
- * The page must remain locked for the duration of the write because we apply
- * the mst fixups, write, and then undo the fixups, so if we were to unlock the
- * page before undoing the fixups, any other user of the page will see the
- * page contents as corrupt.
- *
- * We clear the page uptodate flag for the duration of the function to ensure
- * exclusion for the $MFT/$DATA case against someone mapping an mft record we
- * are about to apply the mst fixups to.
- *
- * Return 0 on success and -errno on error.
- *
- * Based on ntfs_write_block(), ntfs_mft_writepage(), and
- * write_mft_record_nolock().
- */
-static int ntfs_write_mst_block(struct page *page,
-               struct writeback_control *wbc)
-{
-       sector_t block, dblock, rec_block;
-       struct inode *vi = page->mapping->host;
-       ntfs_inode *ni = NTFS_I(vi);
-       ntfs_volume *vol = ni->vol;
-       u8 *kaddr;
-       unsigned int rec_size = ni->itype.index.block_size;
-       ntfs_inode *locked_nis[PAGE_SIZE / NTFS_BLOCK_SIZE];
-       struct buffer_head *bh, *head, *tbh, *rec_start_bh;
-       struct buffer_head *bhs[MAX_BUF_PER_PAGE];
-       runlist_element *rl;
-       int i, nr_locked_nis, nr_recs, nr_bhs, max_bhs, bhs_per_rec, err, err2;
-       unsigned bh_size, rec_size_bits;
-       bool sync, is_mft, page_is_dirty, rec_is_dirty;
-       unsigned char bh_size_bits;
-
-       if (WARN_ON(rec_size < NTFS_BLOCK_SIZE))
-               return -EINVAL;
-
-       ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
-                       "0x%lx.", vi->i_ino, ni->type, page->index);
-       BUG_ON(!NInoNonResident(ni));
-       BUG_ON(!NInoMstProtected(ni));
-       is_mft = (S_ISREG(vi->i_mode) && !vi->i_ino);
-       /*
-        * NOTE: ntfs_write_mst_block() would be called for $MFTMirr if a page
-        * in its page cache were to be marked dirty.  However this should
-        * never happen with the current driver and considering we do not
-        * handle this case here we do want to BUG(), at least for now.
-        */
-       BUG_ON(!(is_mft || S_ISDIR(vi->i_mode) ||
-                       (NInoAttr(ni) && ni->type == AT_INDEX_ALLOCATION)));
-       bh_size = vol->sb->s_blocksize;
-       bh_size_bits = vol->sb->s_blocksize_bits;
-       max_bhs = PAGE_SIZE / bh_size;
-       BUG_ON(!max_bhs);
-       BUG_ON(max_bhs > MAX_BUF_PER_PAGE);
-
-       /* Were we called for sync purposes? */
-       sync = (wbc->sync_mode == WB_SYNC_ALL);
-
-       /* Make sure we have mapped buffers. */
-       bh = head = page_buffers(page);
-       BUG_ON(!bh);
-
-       rec_size_bits = ni->itype.index.block_size_bits;
-       BUG_ON(!(PAGE_SIZE >> rec_size_bits));
-       bhs_per_rec = rec_size >> bh_size_bits;
-       BUG_ON(!bhs_per_rec);
-
-       /* The first block in the page. */
-       rec_block = block = (sector_t)page->index <<
-                       (PAGE_SHIFT - bh_size_bits);
-
-       /* The first out of bounds block for the data size. */
-       dblock = (i_size_read(vi) + bh_size - 1) >> bh_size_bits;
-
-       rl = NULL;
-       err = err2 = nr_bhs = nr_recs = nr_locked_nis = 0;
-       page_is_dirty = rec_is_dirty = false;
-       rec_start_bh = NULL;
-       do {
-               bool is_retry = false;
-
-               if (likely(block < rec_block)) {
-                       if (unlikely(block >= dblock)) {
-                               clear_buffer_dirty(bh);
-                               set_buffer_uptodate(bh);
-                               continue;
-                       }
-                       /*
-                        * This block is not the first one in the record.  We
-                        * ignore the buffer's dirty state because we could
-                        * have raced with a parallel mark_ntfs_record_dirty().
-                        */
-                       if (!rec_is_dirty)
-                               continue;
-                       if (unlikely(err2)) {
-                               if (err2 != -ENOMEM)
-                                       clear_buffer_dirty(bh);
-                               continue;
-                       }
-               } else /* if (block == rec_block) */ {
-                       BUG_ON(block > rec_block);
-                       /* This block is the first one in the record. */
-                       rec_block += bhs_per_rec;
-                       err2 = 0;
-                       if (unlikely(block >= dblock)) {
-                               clear_buffer_dirty(bh);
-                               continue;
-                       }
-                       if (!buffer_dirty(bh)) {
-                               /* Clean records are not written out. */
-                               rec_is_dirty = false;
-                               continue;
-                       }
-                       rec_is_dirty = true;
-                       rec_start_bh = bh;
-               }
-               /* Need to map the buffer if it is not mapped already. */
-               if (unlikely(!buffer_mapped(bh))) {
-                       VCN vcn;
-                       LCN lcn;
-                       unsigned int vcn_ofs;
-
-                       bh->b_bdev = vol->sb->s_bdev;
-                       /* Obtain the vcn and offset of the current block. */
-                       vcn = (VCN)block << bh_size_bits;
-                       vcn_ofs = vcn & vol->cluster_size_mask;
-                       vcn >>= vol->cluster_size_bits;
-                       if (!rl) {
-lock_retry_remap:
-                               down_read(&ni->runlist.lock);
-                               rl = ni->runlist.rl;
-                       }
-                       if (likely(rl != NULL)) {
-                               /* Seek to element containing target vcn. */
-                               while (rl->length && rl[1].vcn <= vcn)
-                                       rl++;
-                               lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
-                       } else
-                               lcn = LCN_RL_NOT_MAPPED;
-                       /* Successful remap. */
-                       if (likely(lcn >= 0)) {
-                               /* Setup buffer head to correct block. */
-                               bh->b_blocknr = ((lcn <<
-                                               vol->cluster_size_bits) +
-                                               vcn_ofs) >> bh_size_bits;
-                               set_buffer_mapped(bh);
-                       } else {
-                               /*
-                                * Remap failed.  Retry to map the runlist once
-                                * unless we are working on $MFT which always
-                                * has the whole of its runlist in memory.
-                                */
-                               if (!is_mft && !is_retry &&
-                                               lcn == LCN_RL_NOT_MAPPED) {
-                                       is_retry = true;
-                                       /*
-                                        * Attempt to map runlist, dropping
-                                        * lock for the duration.
-                                        */
-                                       up_read(&ni->runlist.lock);
-                                       err2 = ntfs_map_runlist(ni, vcn);
-                                       if (likely(!err2))
-                                               goto lock_retry_remap;
-                                       if (err2 == -ENOMEM)
-                                               page_is_dirty = true;
-                                       lcn = err2;
-                               } else {
-                                       err2 = -EIO;
-                                       if (!rl)
-                                               up_read(&ni->runlist.lock);
-                               }
-                               /* Hard error.  Abort writing this record. */
-                               if (!err || err == -ENOMEM)
-                                       err = err2;
-                               bh->b_blocknr = -1;
-                               ntfs_error(vol->sb, "Cannot write ntfs record "
-                                               "0x%llx (inode 0x%lx, "
-                                               "attribute type 0x%x) because "
-                                               "its location on disk could "
-                                               "not be determined (error "
-                                               "code %lli).",
-                                               (long long)block <<
-                                               bh_size_bits >>
-                                               vol->mft_record_size_bits,
-                                               ni->mft_no, ni->type,
-                                               (long long)lcn);
-                               /*
-                                * If this is not the first buffer, remove the
-                                * buffers in this record from the list of
-                                * buffers to write and clear their dirty bit
-                                * if not error -ENOMEM.
-                                */
-                               if (rec_start_bh != bh) {
-                                       while (bhs[--nr_bhs] != rec_start_bh)
-                                               ;
-                                       if (err2 != -ENOMEM) {
-                                               do {
-                                                       clear_buffer_dirty(
-                                                               rec_start_bh);
-                                               } while ((rec_start_bh =
-                                                               rec_start_bh->
-                                                               b_this_page) !=
-                                                               bh);
-                                       }
-                               }
-                               continue;
-                       }
-               }
-               BUG_ON(!buffer_uptodate(bh));
-               BUG_ON(nr_bhs >= max_bhs);
-               bhs[nr_bhs++] = bh;
-       } while (block++, (bh = bh->b_this_page) != head);
-       if (unlikely(rl))
-               up_read(&ni->runlist.lock);
-       /* If there were no dirty buffers, we are done. */
-       if (!nr_bhs)
-               goto done;
-       /* Map the page so we can access its contents. */
-       kaddr = kmap(page);
-       /* Clear the page uptodate flag whilst the mst fixups are applied. */
-       BUG_ON(!PageUptodate(page));
-       ClearPageUptodate(page);
-       for (i = 0; i < nr_bhs; i++) {
-               unsigned int ofs;
-
-               /* Skip buffers which are not at the beginning of records. */
-               if (i % bhs_per_rec)
-                       continue;
-               tbh = bhs[i];
-               ofs = bh_offset(tbh);
-               if (is_mft) {
-                       ntfs_inode *tni;
-                       unsigned long mft_no;
-
-                       /* Get the mft record number. */
-                       mft_no = (((s64)page->index << PAGE_SHIFT) + ofs)
-                                       >> rec_size_bits;
-                       /* Check whether to write this mft record. */
-                       tni = NULL;
-                       if (!ntfs_may_write_mft_record(vol, mft_no,
-                                       (MFT_RECORD*)(kaddr + ofs), &tni)) {
-                               /*
-                                * The record should not be written.  This
-                                * means we need to redirty the page before
-                                * returning.
-                                */
-                               page_is_dirty = true;
-                               /*
-                                * Remove the buffers in this mft record from
-                                * the list of buffers to write.
-                                */
-                               do {
-                                       bhs[i] = NULL;
-                               } while (++i % bhs_per_rec);
-                               continue;
-                       }
-                       /*
-                        * The record should be written.  If a locked ntfs
-                        * inode was returned, add it to the array of locked
-                        * ntfs inodes.
-                        */
-                       if (tni)
-                               locked_nis[nr_locked_nis++] = tni;
-               }
-               /* Apply the mst protection fixups. */
-               err2 = pre_write_mst_fixup((NTFS_RECORD*)(kaddr + ofs),
-                               rec_size);
-               if (unlikely(err2)) {
-                       if (!err || err == -ENOMEM)
-                               err = -EIO;
-                       ntfs_error(vol->sb, "Failed to apply mst fixups "
-                                       "(inode 0x%lx, attribute type 0x%x, "
-                                       "page index 0x%lx, page offset 0x%x)!"
-                                       "  Unmount and run chkdsk.", vi->i_ino,
-                                       ni->type, page->index, ofs);
-                       /*
-                        * Mark all the buffers in this record clean as we do
-                        * not want to write corrupt data to disk.
-                        */
-                       do {
-                               clear_buffer_dirty(bhs[i]);
-                               bhs[i] = NULL;
-                       } while (++i % bhs_per_rec);
-                       continue;
-               }
-               nr_recs++;
-       }
-       /* If no records are to be written out, we are done. */
-       if (!nr_recs)
-               goto unm_done;
-       flush_dcache_page(page);
-       /* Lock buffers and start synchronous write i/o on them. */
-       for (i = 0; i < nr_bhs; i++) {
-               tbh = bhs[i];
-               if (!tbh)
-                       continue;
-               if (!trylock_buffer(tbh))
-                       BUG();
-               /* The buffer dirty state is now irrelevant, just clean it. */
-               clear_buffer_dirty(tbh);
-               BUG_ON(!buffer_uptodate(tbh));
-               BUG_ON(!buffer_mapped(tbh));
-               get_bh(tbh);
-               tbh->b_end_io = end_buffer_write_sync;
-               submit_bh(REQ_OP_WRITE, tbh);
-       }
-       /* Synchronize the mft mirror now if not @sync. */
-       if (is_mft && !sync)
-               goto do_mirror;
-do_wait:
-       /* Wait on i/o completion of buffers. */
-       for (i = 0; i < nr_bhs; i++) {
-               tbh = bhs[i];
-               if (!tbh)
-                       continue;
-               wait_on_buffer(tbh);
-               if (unlikely(!buffer_uptodate(tbh))) {
-                       ntfs_error(vol->sb, "I/O error while writing ntfs "
-                                       "record buffer (inode 0x%lx, "
-                                       "attribute type 0x%x, page index "
-                                       "0x%lx, page offset 0x%lx)!  Unmount "
-                                       "and run chkdsk.", vi->i_ino, ni->type,
-                                       page->index, bh_offset(tbh));
-                       if (!err || err == -ENOMEM)
-                               err = -EIO;
-                       /*
-                        * Set the buffer uptodate so the page and buffer
-                        * states do not become out of sync.
-                        */
-                       set_buffer_uptodate(tbh);
-               }
-       }
-       /* If @sync, now synchronize the mft mirror. */
-       if (is_mft && sync) {
-do_mirror:
-               for (i = 0; i < nr_bhs; i++) {
-                       unsigned long mft_no;
-                       unsigned int ofs;
-
-                       /*
-                        * Skip buffers which are not at the beginning of
-                        * records.
-                        */
-                       if (i % bhs_per_rec)
-                               continue;
-                       tbh = bhs[i];
-                       /* Skip removed buffers (and hence records). */
-                       if (!tbh)
-                               continue;
-                       ofs = bh_offset(tbh);
-                       /* Get the mft record number. */
-                       mft_no = (((s64)page->index << PAGE_SHIFT) + ofs)
-                                       >> rec_size_bits;
-                       if (mft_no < vol->mftmirr_size)
-                               ntfs_sync_mft_mirror(vol, mft_no,
-                                               (MFT_RECORD*)(kaddr + ofs),
-                                               sync);
-               }
-               if (!sync)
-                       goto do_wait;
-       }
-       /* Remove the mst protection fixups again. */
-       for (i = 0; i < nr_bhs; i++) {
-               if (!(i % bhs_per_rec)) {
-                       tbh = bhs[i];
-                       if (!tbh)
-                               continue;
-                       post_write_mst_fixup((NTFS_RECORD*)(kaddr +
-                                       bh_offset(tbh)));
-               }
-       }
-       flush_dcache_page(page);
-unm_done:
-       /* Unlock any locked inodes. */
-       while (nr_locked_nis-- > 0) {
-               ntfs_inode *tni, *base_tni;
-               
-               tni = locked_nis[nr_locked_nis];
-               /* Get the base inode. */
-               mutex_lock(&tni->extent_lock);
-               if (tni->nr_extents >= 0)
-                       base_tni = tni;
-               else {
-                       base_tni = tni->ext.base_ntfs_ino;
-                       BUG_ON(!base_tni);
-               }
-               mutex_unlock(&tni->extent_lock);
-               ntfs_debug("Unlocking %s inode 0x%lx.",
-                               tni == base_tni ? "base" : "extent",
-                               tni->mft_no);
-               mutex_unlock(&tni->mrec_lock);
-               atomic_dec(&tni->count);
-               iput(VFS_I(base_tni));
-       }
-       SetPageUptodate(page);
-       kunmap(page);
-done:
-       if (unlikely(err && err != -ENOMEM)) {
-               /*
-                * Set page error if there is only one ntfs record in the page.
-                * Otherwise we would loose per-record granularity.
-                */
-               if (ni->itype.index.block_size == PAGE_SIZE)
-                       SetPageError(page);
-               NVolSetErrors(vol);
-       }
-       if (page_is_dirty) {
-               ntfs_debug("Page still contains one or more dirty ntfs "
-                               "records.  Redirtying the page starting at "
-                               "record 0x%lx.", page->index <<
-                               (PAGE_SHIFT - rec_size_bits));
-               redirty_page_for_writepage(wbc, page);
-               unlock_page(page);
-       } else {
-               /*
-                * Keep the VM happy.  This must be done otherwise the
-                * radix-tree tag PAGECACHE_TAG_DIRTY remains set even though
-                * the page is clean.
-                */
-               BUG_ON(PageWriteback(page));
-               set_page_writeback(page);
-               unlock_page(page);
-               end_page_writeback(page);
-       }
-       if (likely(!err))
-               ntfs_debug("Done.");
-       return err;
-}
-
-/**
- * ntfs_writepage - write a @page to the backing store
- * @page:      page cache page to write out
- * @wbc:       writeback control structure
- *
- * This is called from the VM when it wants to have a dirty ntfs page cache
- * page cleaned.  The VM has already locked the page and marked it clean.
- *
- * For non-resident attributes, ntfs_writepage() writes the @page by calling
- * the ntfs version of the generic block_write_full_folio() function,
- * ntfs_write_block(), which in turn if necessary creates and writes the
- * buffers associated with the page asynchronously.
- *
- * For resident attributes, OTOH, ntfs_writepage() writes the @page by copying
- * the data to the mft record (which at this stage is most likely in memory).
- * The mft record is then marked dirty and written out asynchronously via the
- * vfs inode dirty code path for the inode the mft record belongs to or via the
- * vm page dirty code path for the page the mft record is in.
- *
- * Based on ntfs_read_folio() and fs/buffer.c::block_write_full_folio().
- *
- * Return 0 on success and -errno on error.
- */
-static int ntfs_writepage(struct page *page, struct writeback_control *wbc)
-{
-       struct folio *folio = page_folio(page);
-       loff_t i_size;
-       struct inode *vi = folio->mapping->host;
-       ntfs_inode *base_ni = NULL, *ni = NTFS_I(vi);
-       char *addr;
-       ntfs_attr_search_ctx *ctx = NULL;
-       MFT_RECORD *m = NULL;
-       u32 attr_len;
-       int err;
-
-retry_writepage:
-       BUG_ON(!folio_test_locked(folio));
-       i_size = i_size_read(vi);
-       /* Is the folio fully outside i_size? (truncate in progress) */
-       if (unlikely(folio->index >= (i_size + PAGE_SIZE - 1) >>
-                       PAGE_SHIFT)) {
-               /*
-                * The folio may have dirty, unmapped buffers.  Make them
-                * freeable here, so the page does not leak.
-                */
-               block_invalidate_folio(folio, 0, folio_size(folio));
-               folio_unlock(folio);
-               ntfs_debug("Write outside i_size - truncated?");
-               return 0;
-       }
-       /*
-        * Only $DATA attributes can be encrypted and only unnamed $DATA
-        * attributes can be compressed.  Index root can have the flags set but
-        * this means to create compressed/encrypted files, not that the
-        * attribute is compressed/encrypted.  Note we need to check for
-        * AT_INDEX_ALLOCATION since this is the type of both directory and
-        * index inodes.
-        */
-       if (ni->type != AT_INDEX_ALLOCATION) {
-               /* If file is encrypted, deny access, just like NT4. */
                if (NInoEncrypted(ni)) {
                        folio_unlock(folio);
-                       BUG_ON(ni->type != AT_DATA);
-                       ntfs_debug("Denying write access to encrypted file.");
-                       return -EACCES;
-               }
-               /* Compressed data streams are handled in compress.c. */
-               if (NInoNonResident(ni) && NInoCompressed(ni)) {
-                       BUG_ON(ni->type != AT_DATA);
-                       BUG_ON(ni->name_len);
-                       // TODO: Implement and replace this with
-                       // return ntfs_write_compressed_block(page);
-                       folio_unlock(folio);
-                       ntfs_error(vi->i_sb, "Writing to compressed files is "
-                                       "not supported yet.  Sorry.");
                        return -EOPNOTSUPP;
                }
-               // TODO: Implement and remove this check.
-               if (NInoNonResident(ni) && NInoSparse(ni)) {
-                       folio_unlock(folio);
-                       ntfs_error(vi->i_sb, "Writing to sparse files is not "
-                                       "supported yet.  Sorry.");
-                       return -EOPNOTSUPP;
-               }
-       }
-       /* NInoNonResident() == NInoIndexAllocPresent() */
-       if (NInoNonResident(ni)) {
-               /* We have to zero every time due to mmap-at-end-of-file. */
-               if (folio->index >= (i_size >> PAGE_SHIFT)) {
-                       /* The folio straddles i_size. */
-                       unsigned int ofs = i_size & (folio_size(folio) - 1);
-                       folio_zero_segment(folio, ofs, folio_size(folio));
-               }
-               /* Handle mst protected attributes. */
-               if (NInoMstProtected(ni))
-                       return ntfs_write_mst_block(page, wbc);
-               /* Normal, non-resident data stream. */
-               return ntfs_write_block(folio, wbc);
-       }
-       /*
-        * Attribute is resident, implying it is not compressed, encrypted, or
-        * mst protected.  This also means the attribute is smaller than an mft
-        * record and hence smaller than a folio, so can simply return error on
-        * any folios with index above 0.  Note the attribute can actually be
-        * marked compressed but if it is resident the actual data is not
-        * compressed so we are ok to ignore the compressed flag here.
-        */
-       BUG_ON(folio_buffers(folio));
-       BUG_ON(!folio_test_uptodate(folio));
-       if (unlikely(folio->index > 0)) {
-               ntfs_error(vi->i_sb, "BUG()! folio->index (0x%lx) > 0.  "
-                               "Aborting write.", folio->index);
-               BUG_ON(folio_test_writeback(folio));
-               folio_start_writeback(folio);
-               folio_unlock(folio);
-               folio_end_writeback(folio);
-               return -EIO;
-       }
-       if (!NInoAttr(ni))
-               base_ni = ni;
-       else
-               base_ni = ni->ext.base_ntfs_ino;
-       /* Map, pin, and lock the mft record. */
-       m = map_mft_record(base_ni);
-       if (IS_ERR(m)) {
-               err = PTR_ERR(m);
-               m = NULL;
-               ctx = NULL;
-               goto err_out;
-       }
-       /*
-        * If a parallel write made the attribute non-resident, drop the mft
-        * record and retry the writepage.
-        */
-       if (unlikely(NInoNonResident(ni))) {
-               unmap_mft_record(base_ni);
-               goto retry_writepage;
-       }
-       ctx = ntfs_attr_get_search_ctx(base_ni, m);
-       if (unlikely(!ctx)) {
-               err = -ENOMEM;
-               goto err_out;
-       }
-       err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
-                       CASE_SENSITIVE, 0, NULL, 0, ctx);
-       if (unlikely(err))
-               goto err_out;
-       /*
-        * Keep the VM happy.  This must be done otherwise
-        * PAGECACHE_TAG_DIRTY remains set even though the folio is clean.
-        */
-       BUG_ON(folio_test_writeback(folio));
-       folio_start_writeback(folio);
-       folio_unlock(folio);
-       attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
-       i_size = i_size_read(vi);
-       if (unlikely(attr_len > i_size)) {
-               /* Race with shrinking truncate or a failed truncate. */
-               attr_len = i_size;
-               /*
-                * If the truncate failed, fix it up now.  If a concurrent
-                * truncate, we do its job, so it does not have to do anything.
-                */
-               err = ntfs_resident_attr_value_resize(ctx->mrec, ctx->attr,
-                               attr_len);
-               /* Shrinking cannot fail. */
-               BUG_ON(err);
+               /* Compressed data streams are handled in compress.c. */
+               if (NInoNonResident(ni) && NInoCompressed(ni))
+                       return ntfs_read_compressed_block(folio);
        }
-       addr = kmap_local_folio(folio, 0);
-       /* Copy the data from the folio to the mft record. */
-       memcpy((u8*)ctx->attr +
-                       le16_to_cpu(ctx->attr->data.resident.value_offset),
-                       addr, attr_len);
-       /* Zero out of bounds area in the page cache folio. */
-       memset(addr + attr_len, 0, folio_size(folio) - attr_len);
-       kunmap_local(addr);
-       flush_dcache_folio(folio);
-       flush_dcache_mft_record_page(ctx->ntfs_ino);
-       /* We are done with the folio. */
-       folio_end_writeback(folio);
-       /* Finally, mark the mft record dirty, so it gets written back. */
-       mark_mft_record_dirty(ctx->ntfs_ino);
-       ntfs_attr_put_search_ctx(ctx);
-       unmap_mft_record(base_ni);
+
+       iomap_bio_read_folio(folio, &ntfs_read_iomap_ops);
        return 0;
-err_out:
-       if (err == -ENOMEM) {
-               ntfs_warning(vi->i_sb, "Error allocating memory. Redirtying "
-                               "page so we try again later.");
-               /*
-                * Put the folio back on mapping->dirty_pages, but leave its
-                * buffers' dirty state as-is.
-                */
-               folio_redirty_for_writepage(wbc, folio);
-               err = 0;
-       } else {
-               ntfs_error(vi->i_sb, "Resident attribute write failed with "
-                               "error %i.", err);
-               folio_set_error(folio);
-               NVolSetErrors(ni->vol);
-       }
-       folio_unlock(folio);
-       if (ctx)
-               ntfs_attr_put_search_ctx(ctx);
-       if (m)
-               unmap_mft_record(base_ni);
-       return err;
 }
 
-#endif /* NTFS_RW */
-
-/**
+/*
  * ntfs_bmap - map logical file block to physical device block
  * @mapping:   address space mapping to which the block to be mapped belongs
  * @block:     logical block to map to its physical device block
@@ -1533,26 +89,24 @@ static sector_t ntfs_bmap(struct address_space *mapping, sector_t block)
 {
        s64 ofs, size;
        loff_t i_size;
-       LCN lcn;
+       s64 lcn;
        unsigned long blocksize, flags;
-       ntfs_inode *ni = NTFS_I(mapping->host);
-       ntfs_volume *vol = ni->vol;
-       unsigned delta;
-       unsigned char blocksize_bits, cluster_size_shift;
+       struct ntfs_inode *ni = NTFS_I(mapping->host);
+       struct ntfs_volume *vol = ni->vol;
+       unsigned int delta;
+       unsigned char blocksize_bits;
 
        ntfs_debug("Entering for mft_no 0x%lx, logical block 0x%llx.",
                        ni->mft_no, (unsigned long long)block);
-       if (ni->type != AT_DATA || !NInoNonResident(ni) || NInoEncrypted(ni)) {
-               ntfs_error(vol->sb, "BMAP does not make sense for %s "
-                               "attributes, returning 0.",
+       if (ni->type != AT_DATA || !NInoNonResident(ni) || NInoEncrypted(ni) ||
+           NInoMstProtected(ni)) {
+               ntfs_error(vol->sb, "BMAP does not make sense for %s attributes, returning 0.",
                                (ni->type != AT_DATA) ? "non-data" :
                                (!NInoNonResident(ni) ? "resident" :
                                "encrypted"));
                return 0;
        }
        /* None of these can happen. */
-       BUG_ON(NInoCompressed(ni));
-       BUG_ON(NInoMstProtected(ni));
        blocksize = vol->sb->s_blocksize;
        blocksize_bits = vol->sb->s_blocksize_bits;
        ofs = (s64)block << blocksize_bits;
@@ -1567,9 +121,9 @@ static sector_t ntfs_bmap(struct address_space *mapping, sector_t block)
         */
        if (unlikely(ofs >= size || (ofs + blocksize > size && size < i_size)))
                goto hole;
-       cluster_size_shift = vol->cluster_size_bits;
        down_read(&ni->runlist.lock);
-       lcn = ntfs_attr_vcn_to_lcn_nolock(ni, ofs >> cluster_size_shift, false);
+       lcn = ntfs_attr_vcn_to_lcn_nolock(ni, ntfs_bytes_to_cluster(vol, ofs),
+                       false);
        up_read(&ni->runlist.lock);
        if (unlikely(lcn < LCN_HOLE)) {
                /*
@@ -1589,14 +143,14 @@ static sector_t ntfs_bmap(struct address_space *mapping, sector_t block)
                         */
                        goto hole;
                case LCN_ENOMEM:
-                       ntfs_error(vol->sb, "Not enough memory to complete "
-                                       "mapping for inode 0x%lx.  "
-                                       "Returning 0.", ni->mft_no);
+                       ntfs_error(vol->sb,
+                               "Not enough memory to complete mapping for inode 0x%lx. Returning 0.",
+                               ni->mft_no);
                        break;
                default:
-                       ntfs_error(vol->sb, "Failed to complete mapping for "
-                                       "inode 0x%lx.  Run chkdsk.  "
-                                       "Returning 0.", ni->mft_no);
+                       ntfs_error(vol->sb,
+                               "Failed to complete mapping for inode 0x%lx.  Run chkdsk. Returning 0.",
+                               ni->mft_no);
                        break;
                }
                return 0;
@@ -1613,132 +167,97 @@ hole:
         */
        delta = ofs & vol->cluster_size_mask;
        if (unlikely(sizeof(block) < sizeof(lcn))) {
-               block = lcn = ((lcn << cluster_size_shift) + delta) >>
+               block = lcn = (ntfs_cluster_to_bytes(vol, lcn) + delta) >>
                                blocksize_bits;
                /* If the block number was truncated return 0. */
                if (unlikely(block != lcn)) {
-                       ntfs_error(vol->sb, "Physical block 0x%llx is too "
-                                       "large to be returned, returning 0.",
-                                       (long long)lcn);
+                       ntfs_error(vol->sb,
+                               "Physical block 0x%llx is too large to be returned, returning 0.",
+                               (long long)lcn);
                        return 0;
                }
        } else
-               block = ((lcn << cluster_size_shift) + delta) >>
+               block = (ntfs_cluster_to_bytes(vol, lcn) + delta) >>
                                blocksize_bits;
        ntfs_debug("Done (returning block 0x%llx).", (unsigned long long)lcn);
        return block;
 }
 
-/*
- * ntfs_normal_aops - address space operations for normal inodes and attributes
- *
- * Note these are not used for compressed or mst protected inodes and
- * attributes.
- */
-const struct address_space_operations ntfs_normal_aops = {
-       .read_folio     = ntfs_read_folio,
-#ifdef NTFS_RW
-       .writepage      = ntfs_writepage,
-       .dirty_folio    = block_dirty_folio,
-#endif /* NTFS_RW */
-       .bmap           = ntfs_bmap,
-       .migrate_folio  = buffer_migrate_folio,
-       .is_partially_uptodate = block_is_partially_uptodate,
-       .error_remove_folio = generic_error_remove_folio,
-};
+static void ntfs_readahead(struct readahead_control *rac)
+{
+       struct address_space *mapping = rac->mapping;
+       struct inode *inode = mapping->host;
+       struct ntfs_inode *ni = NTFS_I(inode);
 
-/*
- * ntfs_compressed_aops - address space operations for compressed inodes
- */
-const struct address_space_operations ntfs_compressed_aops = {
-       .read_folio     = ntfs_read_folio,
-#ifdef NTFS_RW
-       .writepage      = ntfs_writepage,
-       .dirty_folio    = block_dirty_folio,
-#endif /* NTFS_RW */
-       .migrate_folio  = buffer_migrate_folio,
-       .is_partially_uptodate = block_is_partially_uptodate,
-       .error_remove_folio = generic_error_remove_folio,
-};
+       /*
+        * Resident files are not cached in the page cache,
+        * and readahead is not implemented for compressed files.
+        */
+       if (!NInoNonResident(ni) || NInoCompressed(ni))
+               return;
+       iomap_bio_readahead(rac, &ntfs_read_iomap_ops);
+}
 
-/*
- * ntfs_mst_aops - general address space operations for mst protecteed inodes
- *                       and attributes
- */
-const struct address_space_operations ntfs_mst_aops = {
-       .read_folio     = ntfs_read_folio,      /* Fill page with data. */
-#ifdef NTFS_RW
-       .writepage      = ntfs_writepage,       /* Write dirty page to disk. */
-       .dirty_folio    = filemap_dirty_folio,
-#endif /* NTFS_RW */
-       .migrate_folio  = buffer_migrate_folio,
-       .is_partially_uptodate  = block_is_partially_uptodate,
-       .error_remove_folio = generic_error_remove_folio,
-};
+static int ntfs_writepages(struct address_space *mapping,
+               struct writeback_control *wbc)
+{
+       struct inode *inode = mapping->host;
+       struct ntfs_inode *ni = NTFS_I(inode);
+       struct iomap_writepage_ctx wpc = {
+               .inode          = mapping->host,
+               .wbc            = wbc,
+               .ops            = &ntfs_writeback_ops,
+       };
+
+       if (NVolShutdown(ni->vol))
+               return -EIO;
 
-#ifdef NTFS_RW
+       if (!NInoNonResident(ni))
+               return 0;
 
-/**
- * mark_ntfs_record_dirty - mark an ntfs record dirty
- * @page:      page containing the ntfs record to mark dirty
- * @ofs:       byte offset within @page at which the ntfs record begins
- *
- * Set the buffers and the page in which the ntfs record is located dirty.
- *
- * The latter also marks the vfs inode the ntfs record belongs to dirty
- * (I_DIRTY_PAGES only).
- *
- * If the page does not have buffers, we create them and set them uptodate.
- * The page may not be locked which is why we need to handle the buffers under
- * the mapping->i_private_lock.  Once the buffers are marked dirty we no longer
- * need the lock since try_to_free_buffers() does not free dirty buffers.
- */
-void mark_ntfs_record_dirty(struct page *page, const unsigned int ofs) {
-       struct address_space *mapping = page->mapping;
-       ntfs_inode *ni = NTFS_I(mapping->host);
-       struct buffer_head *bh, *head, *buffers_to_free = NULL;
-       unsigned int end, bh_size, bh_ofs;
+       /*
+        * EFS-encrypted files are not supported.
+        * (decryption/encryption is not implemented yet)
+        */
+       if (NInoEncrypted(ni)) {
+               ntfs_debug("Encrypted I/O not supported");
+               return -EOPNOTSUPP;
+       }
 
-       BUG_ON(!PageUptodate(page));
-       end = ofs + ni->itype.index.block_size;
-       bh_size = VFS_I(ni)->i_sb->s_blocksize;
-       spin_lock(&mapping->i_private_lock);
-       if (unlikely(!page_has_buffers(page))) {
-               spin_unlock(&mapping->i_private_lock);
-               bh = head = alloc_page_buffers(page, bh_size, true);
-               spin_lock(&mapping->i_private_lock);
-               if (likely(!page_has_buffers(page))) {
-                       struct buffer_head *tail;
+       return iomap_writepages(&wpc);
+}
 
-                       do {
-                               set_buffer_uptodate(bh);
-                               tail = bh;
-                               bh = bh->b_this_page;
-                       } while (bh);
-                       tail->b_this_page = head;
-                       attach_page_private(page, head);
-               } else
-                       buffers_to_free = bh;
-       }
-       bh = head = page_buffers(page);
-       BUG_ON(!bh);
-       do {
-               bh_ofs = bh_offset(bh);
-               if (bh_ofs + bh_size <= ofs)
-                       continue;
-               if (unlikely(bh_ofs >= end))
-                       break;
-               set_buffer_dirty(bh);
-       } while ((bh = bh->b_this_page) != head);
-       spin_unlock(&mapping->i_private_lock);
-       filemap_dirty_folio(mapping, page_folio(page));
-       if (unlikely(buffers_to_free)) {
-               do {
-                       bh = buffers_to_free->b_this_page;
-                       free_buffer_head(buffers_to_free);
-                       buffers_to_free = bh;
-               } while (buffers_to_free);
-       }
+static int ntfs_swap_activate(struct swap_info_struct *sis,
+               struct file *swap_file, sector_t *span)
+{
+       return iomap_swapfile_activate(sis, swap_file, span,
+                       &ntfs_read_iomap_ops);
 }
 
-#endif /* NTFS_RW */
+const struct address_space_operations ntfs_aops = {
+       .read_folio             = ntfs_read_folio,
+       .readahead              = ntfs_readahead,
+       .writepages             = ntfs_writepages,
+       .direct_IO              = noop_direct_IO,
+       .dirty_folio            = iomap_dirty_folio,
+       .bmap                   = ntfs_bmap,
+       .migrate_folio          = filemap_migrate_folio,
+       .is_partially_uptodate  = iomap_is_partially_uptodate,
+       .error_remove_folio     = generic_error_remove_folio,
+       .release_folio          = iomap_release_folio,
+       .invalidate_folio       = iomap_invalidate_folio,
+       .swap_activate          = ntfs_swap_activate,
+};
+
+const struct address_space_operations ntfs_mft_aops = {
+       .read_folio             = ntfs_read_folio,
+       .readahead              = ntfs_readahead,
+       .writepages             = ntfs_mft_writepages,
+       .dirty_folio            = iomap_dirty_folio,
+       .bmap                   = ntfs_bmap,
+       .migrate_folio          = filemap_migrate_folio,
+       .is_partially_uptodate  = iomap_is_partially_uptodate,
+       .error_remove_folio     = generic_error_remove_folio,
+       .release_folio          = iomap_release_folio,
+       .invalidate_folio       = iomap_invalidate_folio,
+};
diff --git a/fs/ntfs/iomap.c b/fs/ntfs/iomap.c
new file mode 100644 (file)
index 0000000..621645f
--- /dev/null
@@ -0,0 +1,870 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * iomap callack functions
+ *
+ * Copyright (c) 2025 LG Electronics Co., Ltd.
+ */
+
+#include <linux/writeback.h>
+
+#include "attrib.h"
+#include "mft.h"
+#include "ntfs.h"
+#include "iomap.h"
+
+static void ntfs_iomap_put_folio_non_resident(struct inode *inode, loff_t pos,
+                                             unsigned int len, struct folio *folio)
+{
+       struct ntfs_inode *ni = NTFS_I(inode);
+       unsigned long sector_size = 1UL << inode->i_blkbits;
+       loff_t start_down, end_up, init;
+
+       start_down = round_down(pos, sector_size);
+       end_up = (pos + len - 1) | (sector_size - 1);
+       init = ni->initialized_size;
+
+       if (init >= start_down && init <= end_up) {
+               if (init < pos) {
+                       loff_t offset = offset_in_folio(folio, pos + len);
+
+                       if (offset == 0)
+                               offset = folio_size(folio);
+                       folio_zero_segments(folio,
+                                           offset_in_folio(folio, init),
+                                           offset_in_folio(folio, pos),
+                                           offset,
+                                           folio_size(folio));
+
+               } else  {
+                       loff_t offset = max_t(loff_t, pos + len, init);
+
+                       offset = offset_in_folio(folio, offset);
+                       if (offset == 0)
+                               offset = folio_size(folio);
+                       folio_zero_segment(folio,
+                                          offset,
+                                          folio_size(folio));
+               }
+       } else if (init <= pos) {
+               loff_t offset = 0, offset2 = offset_in_folio(folio, pos + len);
+
+               if ((init >> folio_shift(folio)) == (pos >> folio_shift(folio)))
+                       offset = offset_in_folio(folio, init);
+               if (offset2 == 0)
+                       offset2 = folio_size(folio);
+               folio_zero_segments(folio,
+                                   offset,
+                                   offset_in_folio(folio, pos),
+                                   offset2,
+                                   folio_size(folio));
+       }
+       folio_unlock(folio);
+       folio_put(folio);
+}
+
+/*
+ * iomap_zero_range is called for an area beyond the initialized size,
+ * garbage values can be read, so zeroing out is needed.
+ */
+static void ntfs_iomap_put_folio(struct inode *inode, loff_t pos,
+               unsigned int len, struct folio *folio)
+{
+       if (NInoNonResident(NTFS_I(inode)))
+               return ntfs_iomap_put_folio_non_resident(inode, pos,
+                                                        len, folio);
+       folio_unlock(folio);
+       folio_put(folio);
+}
+
+const struct iomap_write_ops ntfs_iomap_folio_ops = {
+       .put_folio = ntfs_iomap_put_folio,
+};
+
+static int ntfs_read_iomap_begin_resident(struct inode *inode, loff_t offset, loff_t length,
+               unsigned int flags, struct iomap *iomap)
+{
+       struct ntfs_inode *base_ni, *ni = NTFS_I(inode);
+       struct ntfs_attr_search_ctx *ctx;
+       loff_t i_size;
+       u32 attr_len;
+       int err = 0;
+       char *kattr;
+
+       if (NInoAttr(ni))
+               base_ni = ni->ext.base_ntfs_ino;
+       else
+               base_ni = ni;
+
+       ctx = ntfs_attr_get_search_ctx(base_ni, NULL);
+       if (!ctx) {
+               err = -ENOMEM;
+               goto out;
+       }
+
+       err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+                       CASE_SENSITIVE, 0, NULL, 0, ctx);
+       if (unlikely(err))
+               goto out;
+
+       attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
+       if (unlikely(attr_len > ni->initialized_size))
+               attr_len = ni->initialized_size;
+       i_size = i_size_read(inode);
+
+       if (unlikely(attr_len > i_size)) {
+               /* Race with shrinking truncate. */
+               attr_len = i_size;
+       }
+
+       if (offset >= attr_len) {
+               if (flags & IOMAP_REPORT)
+                       err = -ENOENT;
+               else {
+                       iomap->type = IOMAP_HOLE;
+                       iomap->offset = offset;
+                       iomap->length = length;
+               }
+               goto out;
+       }
+
+       kattr = (u8 *)ctx->attr + le16_to_cpu(ctx->attr->data.resident.value_offset);
+
+       iomap->inline_data = kmemdup(kattr, attr_len, GFP_KERNEL);
+       if (!iomap->inline_data) {
+               err = -ENOMEM;
+               goto out;
+       }
+
+       iomap->type = IOMAP_INLINE;
+       iomap->offset = 0;
+       iomap->length = attr_len;
+
+out:
+       if (ctx)
+               ntfs_attr_put_search_ctx(ctx);
+
+       return err;
+}
+
+/*
+ * ntfs_read_iomap_begin_non_resident - map non-resident NTFS file data
+ * @inode:             inode to map
+ * @offset:            file offset to map
+ * @length:            length of mapping
+ * @flags:             IOMAP flags
+ * @iomap:             iomap structure to fill
+ * @need_unwritten:    true if UNWRITTEN extent type is needed
+ *
+ * Map a range of a non-resident NTFS file to an iomap extent.
+ *
+ * NTFS UNWRITTEN extent handling:
+ * ================================
+ * The concept of an unwritten extent in NTFS is slightly different from
+ * that of other filesystems. NTFS conceptually manages only a single
+ * continuous unwritten region, which is strictly defined based on
+ * initialized_size.
+ *
+ * File offset layout:
+ *   0                        initialized_size                   i_size(EOF)
+ *   |----------#0----------|----------#1----------|----------#2----------|
+ *   | Actual data          | Pre-allocated        | Pre-allocated        |
+ *   | (user written)       | (within initialized) | (initialized ~ EOF)  |
+ *   |----------------------|----------------------|----------------------|
+ *   MAPPED                 MAPPED                 UNWRITTEN (conditionally)
+ *
+ * Region #0: User-written data, initialized and valid.
+ * Region #1: Pre-allocated within initialized_size, must be zero-initialized
+ *            by the filesystem before exposure to userspace.
+ * Region #2: Pre-allocated beyond initialized_size, does not need initialization.
+ *
+ * The @need_unwritten parameter controls whether region #2 is mapped as
+ * IOMAP_UNWRITTEN or IOMAP_MAPPED:
+ * - For seek operations (SEEK_DATA/SEEK_HOLE): IOMAP_MAPPED is needed to
+ *   prevent iomap_seek_data from incorrectly interpreting pre-allocated
+ *   space as a hole. Since NTFS does not support multiple unwritten extents,
+ *   all pre-allocated regions should be treated as data, not holes.
+ * - For zero_range operations: IOMAP_MAPPED is needed to be zeroed out.
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+static int ntfs_read_iomap_begin_non_resident(struct inode *inode, loff_t offset,
+               loff_t length, unsigned int flags, struct iomap *iomap,
+               bool need_unwritten)
+{
+       struct ntfs_inode *ni = NTFS_I(inode);
+       s64 vcn;
+       s64 lcn;
+       struct runlist_element *rl;
+       struct ntfs_volume *vol = ni->vol;
+       loff_t vcn_ofs;
+       loff_t rl_length;
+
+       vcn = ntfs_bytes_to_cluster(vol, offset);
+       vcn_ofs = ntfs_bytes_to_cluster_off(vol, offset);
+
+       down_write(&ni->runlist.lock);
+       rl = ntfs_attr_vcn_to_rl(ni, vcn, &lcn);
+       if (IS_ERR(rl)) {
+               up_write(&ni->runlist.lock);
+               return PTR_ERR(rl);
+       }
+
+       if (flags & IOMAP_REPORT) {
+               if (lcn < LCN_HOLE) {
+                       up_write(&ni->runlist.lock);
+                       return -ENOENT;
+               }
+       } else if (lcn < LCN_ENOENT) {
+               up_write(&ni->runlist.lock);
+               return -EINVAL;
+       }
+
+       iomap->bdev = inode->i_sb->s_bdev;
+       iomap->offset = offset;
+
+       if (lcn <= LCN_DELALLOC) {
+               if (lcn == LCN_DELALLOC)
+                       iomap->type = IOMAP_DELALLOC;
+               else
+                       iomap->type = IOMAP_HOLE;
+               iomap->addr = IOMAP_NULL_ADDR;
+       } else {
+               if (need_unwritten && offset >= ni->initialized_size)
+                       iomap->type = IOMAP_UNWRITTEN;
+               else
+                       iomap->type = IOMAP_MAPPED;
+               iomap->addr = ntfs_cluster_to_bytes(vol, lcn) + vcn_ofs;
+       }
+
+       rl_length = ntfs_cluster_to_bytes(vol, rl->length - (vcn - rl->vcn));
+
+       if (rl_length == 0 && rl->lcn > LCN_DELALLOC) {
+               ntfs_error(inode->i_sb,
+                               "runlist(vcn : %lld, length : %lld, lcn : %lld) is corrupted\n",
+                               rl->vcn, rl->length, rl->lcn);
+               up_write(&ni->runlist.lock);
+               return -EIO;
+       }
+
+       if (rl_length && length > rl_length - vcn_ofs)
+               iomap->length = rl_length - vcn_ofs;
+       else
+               iomap->length = length;
+       up_write(&ni->runlist.lock);
+
+       if (!(flags & IOMAP_ZERO) &&
+                       iomap->type == IOMAP_MAPPED &&
+                       iomap->offset < ni->initialized_size &&
+                       iomap->offset + iomap->length > ni->initialized_size) {
+               iomap->length = round_up(ni->initialized_size, 1 << inode->i_blkbits) -
+                       iomap->offset;
+       }
+       iomap->flags |= IOMAP_F_MERGED;
+
+       return 0;
+}
+
+static int __ntfs_read_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
+               unsigned int flags, struct iomap *iomap, struct iomap *srcmap,
+               bool need_unwritten)
+{
+       if (NInoNonResident(NTFS_I(inode)))
+               return ntfs_read_iomap_begin_non_resident(inode, offset, length,
+                               flags, iomap, need_unwritten);
+       return ntfs_read_iomap_begin_resident(inode, offset, length,
+                                            flags, iomap);
+}
+
+static int ntfs_read_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
+               unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
+{
+       return __ntfs_read_iomap_begin(inode, offset, length, flags, iomap,
+                       srcmap, true);
+}
+
+static int ntfs_read_iomap_end(struct inode *inode, loff_t pos, loff_t length,
+               ssize_t written, unsigned int flags, struct iomap *iomap)
+{
+       if (iomap->type == IOMAP_INLINE)
+               kfree(iomap->inline_data);
+
+       return written;
+}
+
+const struct iomap_ops ntfs_read_iomap_ops = {
+       .iomap_begin = ntfs_read_iomap_begin,
+       .iomap_end = ntfs_read_iomap_end,
+};
+
+/*
+ * Check that the cached iomap still matches the NTFS runlist before
+ * iomap_zero_range() is called. if the runlist changes while iomap is
+ * iterating a cached iomap, iomap_zero_range() may overwrite folios
+ * that have been already written with valid data.
+ */
+static bool ntfs_iomap_valid(struct inode *inode, const struct iomap *iomap)
+{
+       struct ntfs_inode *ni = NTFS_I(inode);
+       struct runlist_element *rl;
+       s64 vcn, lcn;
+
+       if (!NInoNonResident(ni))
+               return false;
+
+       vcn = iomap->offset >> ni->vol->cluster_size_bits;
+
+       down_read(&ni->runlist.lock);
+       rl = __ntfs_attr_find_vcn_nolock(&ni->runlist, vcn);
+       if (IS_ERR(rl)) {
+               up_read(&ni->runlist.lock);
+               return false;
+       }
+       lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
+       up_read(&ni->runlist.lock);
+       return lcn == LCN_DELALLOC;
+}
+
+static const struct iomap_write_ops ntfs_zero_iomap_folio_ops = {
+       .put_folio = ntfs_iomap_put_folio,
+       .iomap_valid = ntfs_iomap_valid,
+};
+
+static int ntfs_seek_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
+               unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
+{
+       return __ntfs_read_iomap_begin(inode, offset, length, flags, iomap,
+                       srcmap, false);
+}
+
+static int ntfs_zero_read_iomap_end(struct inode *inode, loff_t pos, loff_t length,
+               ssize_t written, unsigned int flags, struct iomap *iomap)
+{
+       if ((flags & IOMAP_ZERO) && (iomap->flags & IOMAP_F_STALE))
+               return -EPERM;
+       return written;
+}
+
+static const struct iomap_ops ntfs_zero_read_iomap_ops = {
+       .iomap_begin = ntfs_seek_iomap_begin,
+       .iomap_end = ntfs_zero_read_iomap_end,
+};
+
+const struct iomap_ops ntfs_seek_iomap_ops = {
+       .iomap_begin = ntfs_seek_iomap_begin,
+       .iomap_end = ntfs_read_iomap_end,
+};
+
+int ntfs_dio_zero_range(struct inode *inode, loff_t offset, loff_t length)
+{
+       if ((offset | length) & (SECTOR_SIZE - 1))
+               return -EINVAL;
+
+       return  blkdev_issue_zeroout(inode->i_sb->s_bdev,
+                                    offset >> SECTOR_SHIFT,
+                                    length >> SECTOR_SHIFT,
+                                    GFP_NOFS,
+                                    BLKDEV_ZERO_NOUNMAP);
+}
+
+static int ntfs_zero_range(struct inode *inode, loff_t offset, loff_t length)
+{
+       return iomap_zero_range(inode,
+                               offset, length,
+                               NULL,
+                               &ntfs_zero_read_iomap_ops,
+                               &ntfs_zero_iomap_folio_ops,
+                               NULL);
+}
+
+static int ntfs_write_simple_iomap_begin_non_resident(struct inode *inode, loff_t offset,
+                                                     loff_t length, struct iomap *iomap)
+{
+       struct ntfs_inode *ni = NTFS_I(inode);
+       struct ntfs_volume *vol = ni->vol;
+       loff_t vcn_ofs, rl_length;
+       struct runlist_element *rl, *rlc;
+       bool is_retry = false;
+       int err;
+       s64 vcn, lcn;
+       s64 max_clu_count =
+               ntfs_bytes_to_cluster(vol, round_up(length, vol->cluster_size));
+
+       vcn = ntfs_bytes_to_cluster(vol, offset);
+       vcn_ofs = ntfs_bytes_to_cluster_off(vol, offset);
+
+       down_read(&ni->runlist.lock);
+       rl = ni->runlist.rl;
+       if (!rl) {
+               up_read(&ni->runlist.lock);
+               err = ntfs_map_runlist(ni, vcn);
+               if (err) {
+                       mutex_unlock(&ni->mrec_lock);
+                       return -ENOENT;
+               }
+               down_read(&ni->runlist.lock);
+               rl = ni->runlist.rl;
+       }
+       up_read(&ni->runlist.lock);
+
+       down_write(&ni->runlist.lock);
+remap_rl:
+       /* Seek to element containing target vcn. */
+       rl = __ntfs_attr_find_vcn_nolock(&ni->runlist, vcn);
+       if (IS_ERR(rl)) {
+               up_write(&ni->runlist.lock);
+               mutex_unlock(&ni->mrec_lock);
+               return -EIO;
+       }
+       lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
+
+       if (lcn <= LCN_RL_NOT_MAPPED && is_retry == false) {
+               is_retry = true;
+               if (!ntfs_map_runlist_nolock(ni, vcn, NULL)) {
+                       rl = ni->runlist.rl;
+                       goto remap_rl;
+               }
+       }
+
+       max_clu_count = min(max_clu_count, rl->length - (vcn - rl->vcn));
+       if (max_clu_count == 0) {
+               ntfs_error(inode->i_sb,
+                               "runlist(vcn : %lld, length : %lld) is corrupted\n",
+                               rl->vcn, rl->length);
+               up_write(&ni->runlist.lock);
+               mutex_unlock(&ni->mrec_lock);
+               return -EIO;
+       }
+
+       iomap->bdev = inode->i_sb->s_bdev;
+       iomap->offset = offset;
+
+       if (lcn <= LCN_DELALLOC) {
+               if (lcn < LCN_DELALLOC) {
+                       max_clu_count =
+                               ntfs_available_clusters_count(vol, max_clu_count);
+                       if (max_clu_count < 0) {
+                               err = max_clu_count;
+                               up_write(&ni->runlist.lock);
+                               mutex_unlock(&ni->mrec_lock);
+                               return err;
+                       }
+               }
+
+               iomap->type = IOMAP_DELALLOC;
+               iomap->addr = IOMAP_NULL_ADDR;
+
+               if (lcn <= LCN_HOLE) {
+                       size_t new_rl_count;
+
+                       rlc = kmalloc(sizeof(struct runlist_element) * 2,
+                                       GFP_NOFS);
+                       if (!rlc) {
+                               up_write(&ni->runlist.lock);
+                               mutex_unlock(&ni->mrec_lock);
+                               return -ENOMEM;
+                       }
+
+                       rlc->vcn = vcn;
+                       rlc->lcn = LCN_DELALLOC;
+                       rlc->length = max_clu_count;
+
+                       rlc[1].vcn = vcn + max_clu_count;
+                       rlc[1].lcn = LCN_RL_NOT_MAPPED;
+                       rlc[1].length = 0;
+
+                       rl = ntfs_runlists_merge(&ni->runlist, rlc, 0,
+                                       &new_rl_count);
+                       if (IS_ERR(rl)) {
+                               ntfs_error(vol->sb, "Failed to merge runlists");
+                               up_write(&ni->runlist.lock);
+                               mutex_unlock(&ni->mrec_lock);
+                               kvfree(rlc);
+                               return PTR_ERR(rl);
+                       }
+
+                       ni->runlist.rl = rl;
+                       ni->runlist.count = new_rl_count;
+                       ni->i_dealloc_clusters += max_clu_count;
+               }
+               up_write(&ni->runlist.lock);
+               mutex_unlock(&ni->mrec_lock);
+
+               if (lcn < LCN_DELALLOC)
+                       ntfs_hold_dirty_clusters(vol, max_clu_count);
+
+               rl_length = ntfs_cluster_to_bytes(vol, max_clu_count);
+               if (length > rl_length - vcn_ofs)
+                       iomap->length = rl_length - vcn_ofs;
+               else
+                       iomap->length = length;
+
+               iomap->flags = IOMAP_F_NEW;
+               if (lcn <= LCN_HOLE) {
+                       loff_t end = offset + length;
+
+                       if (vcn_ofs || ((vol->cluster_size > iomap->length) &&
+                                       end < ni->initialized_size)) {
+                               loff_t z_start, z_end;
+
+                               z_start = vcn << vol->cluster_size_bits;
+                               z_end = min_t(loff_t, z_start + vol->cluster_size,
+                                             i_size_read(inode));
+                               if (z_end > z_start)
+                                       err = ntfs_zero_range(inode,
+                                                             z_start,
+                                                             z_end - z_start);
+                       }
+                       if ((!err || err == -EPERM) &&
+                           max_clu_count > 1 &&
+                           (iomap->length & vol->cluster_size_mask &&
+                            end < ni->initialized_size)) {
+                               loff_t z_start, z_end;
+
+                               z_start = (vcn + max_clu_count - 1) <<
+                                       vol->cluster_size_bits;
+                               z_end = min_t(loff_t, z_start + vol->cluster_size,
+                                             i_size_read(inode));
+                               if (z_end > z_start)
+                                       err = ntfs_zero_range(inode,
+                                                             z_start,
+                                                             z_end - z_start);
+                       }
+
+                       if (err == -EPERM)
+                               err = 0;
+                       if (err) {
+                               ntfs_release_dirty_clusters(vol, max_clu_count);
+                               return err;
+                       }
+               }
+       } else {
+               up_write(&ni->runlist.lock);
+               mutex_unlock(&ni->mrec_lock);
+
+               iomap->type = IOMAP_MAPPED;
+               iomap->addr = ntfs_cluster_to_bytes(vol, lcn) + vcn_ofs;
+
+               rl_length = ntfs_cluster_to_bytes(vol, max_clu_count);
+               if (length > rl_length - vcn_ofs)
+                       iomap->length = rl_length - vcn_ofs;
+               else
+                       iomap->length = length;
+       }
+
+       return 0;
+}
+
+#define NTFS_IOMAP_FLAGS_BEGIN         BIT(1)
+#define NTFS_IOMAP_FLAGS_DIO           BIT(2)
+#define        NTFS_IOMAP_FLAGS_MKWRITE        BIT(3)
+#define        NTFS_IOMAP_FLAGS_WRITEBACK      BIT(4)
+
+static int ntfs_write_da_iomap_begin_non_resident(struct inode *inode,
+               loff_t offset, loff_t length, unsigned int flags,
+               struct iomap *iomap, int ntfs_iomap_flags)
+{
+       struct ntfs_inode *ni = NTFS_I(inode);
+       struct ntfs_volume *vol = ni->vol;
+       loff_t vcn_ofs, rl_length;
+       s64 vcn, start_lcn, lcn_count;
+       bool balloc = false, update_mp;
+       int err;
+       s64 max_clu_count =
+               ntfs_bytes_to_cluster(vol, round_up(length, vol->cluster_size));
+
+       vcn = ntfs_bytes_to_cluster(vol, offset);
+       vcn_ofs = ntfs_bytes_to_cluster_off(vol, offset);
+
+       update_mp = ntfs_iomap_flags & (NTFS_IOMAP_FLAGS_DIO | NTFS_IOMAP_FLAGS_MKWRITE) ||
+                       NInoAttr(ni) || ni->mft_no < FILE_first_user;
+       down_write(&ni->runlist.lock);
+       err = ntfs_attr_map_cluster(ni, vcn, &start_lcn, &lcn_count,
+                       max_clu_count, &balloc, update_mp,
+                       ntfs_iomap_flags & NTFS_IOMAP_FLAGS_WRITEBACK);
+       up_write(&ni->runlist.lock);
+       mutex_unlock(&ni->mrec_lock);
+       if (err) {
+               ni->i_dealloc_clusters = 0;
+               return err;
+       }
+
+       iomap->bdev = inode->i_sb->s_bdev;
+       iomap->offset = offset;
+
+       rl_length = ntfs_cluster_to_bytes(vol, lcn_count);
+       if (length > rl_length - vcn_ofs)
+               iomap->length = rl_length - vcn_ofs;
+       else
+               iomap->length = length;
+
+       if (start_lcn == LCN_HOLE)
+               iomap->type = IOMAP_HOLE;
+       else
+               iomap->type = IOMAP_MAPPED;
+       if (balloc == true)
+               iomap->flags = IOMAP_F_NEW;
+
+       iomap->addr = ntfs_cluster_to_bytes(vol, start_lcn) + vcn_ofs;
+
+       if (balloc == true) {
+               if (flags & IOMAP_DIRECT ||
+                   ntfs_iomap_flags & NTFS_IOMAP_FLAGS_MKWRITE) {
+                       loff_t end = offset + length;
+
+                       if (vcn_ofs || ((vol->cluster_size > iomap->length) &&
+                                       end < ni->initialized_size))
+                               err = ntfs_dio_zero_range(inode,
+                                                         start_lcn <<
+                                                         vol->cluster_size_bits,
+                                                         vol->cluster_size);
+                       if (!err && lcn_count > 1 &&
+                           (iomap->length & vol->cluster_size_mask &&
+                            end < ni->initialized_size))
+                               err = ntfs_dio_zero_range(inode,
+                                                         (start_lcn + lcn_count - 1) <<
+                                                         vol->cluster_size_bits,
+                                                         vol->cluster_size);
+               } else {
+                       if (lcn_count > ni->i_dealloc_clusters)
+                               ni->i_dealloc_clusters = 0;
+                       else
+                               ni->i_dealloc_clusters -= lcn_count;
+               }
+               if (err < 0)
+                       return err;
+       }
+
+       if (ntfs_iomap_flags & NTFS_IOMAP_FLAGS_MKWRITE &&
+           iomap->offset + iomap->length > ni->initialized_size) {
+               err = ntfs_attr_set_initialized_size(ni, iomap->offset +
+                               iomap->length);
+       }
+
+       return err;
+}
+
+static int ntfs_write_iomap_begin_resident(struct inode *inode, loff_t offset,
+               struct iomap *iomap)
+{
+       struct ntfs_inode *ni = NTFS_I(inode);
+       struct attr_record *a;
+       struct ntfs_attr_search_ctx *ctx;
+       u32 attr_len;
+       int err = 0;
+       char *kattr;
+
+       ctx = ntfs_attr_get_search_ctx(ni, NULL);
+       if (!ctx) {
+               err = -ENOMEM;
+               goto out;
+       }
+
+       err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+                       CASE_SENSITIVE, 0, NULL, 0, ctx);
+       if (err) {
+               if (err == -ENOENT)
+                       err = -EIO;
+               goto out;
+       }
+
+       a = ctx->attr;
+       /* The total length of the attribute value. */
+       attr_len = le32_to_cpu(a->data.resident.value_length);
+       kattr = (u8 *)a + le16_to_cpu(a->data.resident.value_offset);
+
+       iomap->inline_data = kmemdup(kattr, attr_len, GFP_KERNEL);
+       if (!iomap->inline_data) {
+               err = -ENOMEM;
+               goto out;
+       }
+
+       iomap->type = IOMAP_INLINE;
+       iomap->offset = 0;
+       /* iomap requires there is only one INLINE_DATA extent */
+       iomap->length = attr_len;
+
+out:
+       if (ctx)
+               ntfs_attr_put_search_ctx(ctx);
+       mutex_unlock(&ni->mrec_lock);
+       return err;
+}
+
+static int ntfs_write_iomap_begin_non_resident(struct inode *inode, loff_t offset,
+                                              loff_t length, unsigned int flags,
+                                              struct iomap *iomap, int ntfs_iomap_flags)
+{
+       struct ntfs_inode *ni = NTFS_I(inode);
+
+       if (ntfs_iomap_flags & (NTFS_IOMAP_FLAGS_BEGIN | NTFS_IOMAP_FLAGS_DIO) &&
+           offset + length > ni->initialized_size) {
+               int ret;
+
+               ret = ntfs_extend_initialized_size(inode, offset,
+                                                  offset + length,
+                                                  ntfs_iomap_flags &
+                                                  NTFS_IOMAP_FLAGS_DIO);
+               if (ret < 0)
+                       return ret;
+       }
+
+       mutex_lock(&ni->mrec_lock);
+       if (ntfs_iomap_flags & NTFS_IOMAP_FLAGS_BEGIN)
+               return  ntfs_write_simple_iomap_begin_non_resident(inode, offset,
+                                                                  length, iomap);
+       else
+               return ntfs_write_da_iomap_begin_non_resident(inode,
+                                                             offset, length,
+                                                             flags, iomap,
+                                                             ntfs_iomap_flags);
+}
+
+static int __ntfs_write_iomap_begin(struct inode *inode, loff_t offset,
+                                   loff_t length, unsigned int flags,
+                                   struct iomap *iomap, int ntfs_iomap_flags)
+{
+       struct ntfs_inode *ni = NTFS_I(inode);
+       loff_t end = offset + length;
+
+       if (NVolShutdown(ni->vol))
+               return -EIO;
+
+       if (ntfs_iomap_flags & (NTFS_IOMAP_FLAGS_BEGIN | NTFS_IOMAP_FLAGS_DIO) &&
+           end > ni->data_size) {
+               struct ntfs_volume *vol = ni->vol;
+               int ret;
+
+               mutex_lock(&ni->mrec_lock);
+               if (end > ni->allocated_size &&
+                   end < ni->allocated_size + vol->preallocated_size)
+                       ret = ntfs_attr_expand(ni, end,
+                                       ni->allocated_size + vol->preallocated_size);
+               else
+                       ret = ntfs_attr_expand(ni, end, 0);
+               mutex_unlock(&ni->mrec_lock);
+               if (ret)
+                       return ret;
+       }
+
+       if (!NInoNonResident(ni)) {
+               mutex_lock(&ni->mrec_lock);
+               return ntfs_write_iomap_begin_resident(inode, offset, iomap);
+       }
+       return  ntfs_write_iomap_begin_non_resident(inode, offset, length, flags,
+                                                   iomap, ntfs_iomap_flags);
+}
+
+static int ntfs_write_iomap_begin(struct inode *inode, loff_t offset,
+                                 loff_t length, unsigned int flags,
+                                 struct iomap *iomap, struct iomap *srcmap)
+{
+       return __ntfs_write_iomap_begin(inode, offset, length, flags, iomap,
+                       NTFS_IOMAP_FLAGS_BEGIN);
+}
+
+static int ntfs_write_iomap_end_resident(struct inode *inode, loff_t pos,
+                                        loff_t length, ssize_t written,
+                                        unsigned int flags, struct iomap *iomap)
+{
+       struct ntfs_inode *ni = NTFS_I(inode);
+       struct ntfs_attr_search_ctx *ctx;
+       u32 attr_len;
+       int err;
+       char *kattr;
+
+       mutex_lock(&ni->mrec_lock);
+       ctx = ntfs_attr_get_search_ctx(ni, NULL);
+       if (!ctx) {
+               written = -ENOMEM;
+               mutex_unlock(&ni->mrec_lock);
+               return written;
+       }
+
+       err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+                              CASE_SENSITIVE, 0, NULL, 0, ctx);
+       if (err) {
+               if (err == -ENOENT)
+                       err = -EIO;
+               written = err;
+               goto err_out;
+       }
+
+       /* The total length of the attribute value. */
+       attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
+       if (pos >= attr_len || pos + written > attr_len)
+               goto err_out;
+
+       kattr = (u8 *)ctx->attr + le16_to_cpu(ctx->attr->data.resident.value_offset);
+       memcpy(kattr + pos, iomap_inline_data(iomap, pos), written);
+       mark_mft_record_dirty(ctx->ntfs_ino);
+err_out:
+       ntfs_attr_put_search_ctx(ctx);
+       kfree(iomap->inline_data);
+       mutex_unlock(&ni->mrec_lock);
+       return written;
+
+}
+
+static int ntfs_write_iomap_end(struct inode *inode, loff_t pos, loff_t length,
+                               ssize_t written, unsigned int flags,
+                               struct iomap *iomap)
+{
+       if (iomap->type == IOMAP_INLINE)
+               return ntfs_write_iomap_end_resident(inode, pos, length,
+                                                    written, flags, iomap);
+       return written;
+}
+
+const struct iomap_ops ntfs_write_iomap_ops = {
+       .iomap_begin            = ntfs_write_iomap_begin,
+       .iomap_end              = ntfs_write_iomap_end,
+};
+
+static int ntfs_page_mkwrite_iomap_begin(struct inode *inode, loff_t offset,
+                                 loff_t length, unsigned int flags,
+                                 struct iomap *iomap, struct iomap *srcmap)
+{
+       return __ntfs_write_iomap_begin(inode, offset, length, flags, iomap,
+                       NTFS_IOMAP_FLAGS_MKWRITE);
+}
+
+const struct iomap_ops ntfs_page_mkwrite_iomap_ops = {
+       .iomap_begin            = ntfs_page_mkwrite_iomap_begin,
+       .iomap_end              = ntfs_write_iomap_end,
+};
+
+static int ntfs_dio_iomap_begin(struct inode *inode, loff_t offset,
+                                 loff_t length, unsigned int flags,
+                                 struct iomap *iomap, struct iomap *srcmap)
+{
+       return __ntfs_write_iomap_begin(inode, offset, length, flags, iomap,
+                       NTFS_IOMAP_FLAGS_DIO);
+}
+
+const struct iomap_ops ntfs_dio_iomap_ops = {
+       .iomap_begin            = ntfs_dio_iomap_begin,
+       .iomap_end              = ntfs_write_iomap_end,
+};
+
+static ssize_t ntfs_writeback_range(struct iomap_writepage_ctx *wpc,
+               struct folio *folio, u64 offset, unsigned int len, u64 end_pos)
+{
+       if (offset < wpc->iomap.offset ||
+           offset >= wpc->iomap.offset + wpc->iomap.length) {
+               int error;
+
+               error = __ntfs_write_iomap_begin(wpc->inode, offset,
+                               NTFS_I(wpc->inode)->allocated_size - offset,
+                               IOMAP_WRITE, &wpc->iomap,
+                               NTFS_IOMAP_FLAGS_WRITEBACK);
+               if (error)
+                       return error;
+       }
+
+       return iomap_add_to_ioend(wpc, folio, offset, end_pos, len);
+}
+
+const struct iomap_writeback_ops ntfs_writeback_ops = {
+       .writeback_range        = ntfs_writeback_range,
+       .writeback_submit       = iomap_ioend_writeback_submit,
+};