fs/ntfs3: add delayed-allocation (delalloc) support

This patch implements delayed allocation (delalloc) in ntfs3 driver.

It introduces an in-memory delayed-runlist (run_da) and the helpers to
track, reserve and later convert those delayed reservations into real
clusters at writeback time. The change keeps on-disk formats untouched and
focuses on pagecache integration, correctness and safe interaction with
fallocate, truncate, and dio/iomap paths.

Key points:

- add run_da (delay-allocated run tree) and bookkeeping for delayed clusters.

- mark ranges as delalloc (DELALLOC_LCN) instead of immediately allocating.
  Actual allocation performed later (writeback / attr_set_size_ex / explicit
  flush paths).

- direct i/o / iomap paths updated to avoid dio collisions with
  delalloc: dio falls back or forces allocation of delayed blocks before
  proceeding.

- punch/collapse/truncate/fallocate check and cancel delay-alloc reservations.
  Sparse/compressed files handled specially.

- free-space checks updated (ntfs_check_free_space) to account for reserved
  delalloc clusters and MFT record budgeting.

- delayed allocations are committed on last writer (file release) and on
  explicit allocation flush paths.

Tested-by: syzbot@syzkaller.appspotmail.com
Reported-by: syzbot+2bd8e813c7f767aa9bb1@syzkaller.appspotmail.com
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

Author: aalexandrovich

fs/ntfs3/attrib.c

@@ -345,8 +345,8 @@ int al_add_le(struct ntfs_inode *ni, enum ATTR_TYPE type, const __le16 *name,
 	le->id = id;
 	memcpy(le->name, name, sizeof(short) * name_len);
 
-	err = attr_set_size(ni, ATTR_LIST, NULL, 0, &al->run, new_size,
-			    &new_size, true, &attr);
+	err = attr_set_size_ex(ni, ATTR_LIST, NULL, 0, &al->run, new_size,
+			       &new_size, true, &attr, false);
 	if (err) {
 		/* Undo memmove above. */
 		memmove(le, Add2Ptr(le, sz), old_size - off);
@@ -404,8 +404,8 @@ int al_update(struct ntfs_inode *ni, int sync)
 	 * Attribute list increased on demand in al_add_le.
 	 * Attribute list decreased here.
 	 */
-	err = attr_set_size(ni, ATTR_LIST, NULL, 0, &al->run, al->size, NULL,
-			    false, &attr);
+	err = attr_set_size_ex(ni, ATTR_LIST, NULL, 0, &al->run, al->size, NULL,
+			       false, &attr, false);
 	if (err)
 		goto out;