1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (C) 2007 Oracle.  All rights reserved.
   4 */
   5
   6#include <linux/fs.h>
   7#include <linux/pagemap.h>
   8#include <linux/time.h>
   9#include <linux/init.h>
  10#include <linux/string.h>
  11#include <linux/backing-dev.h>
  12#include <linux/falloc.h>
  13#include <linux/writeback.h>
  14#include <linux/compat.h>
  15#include <linux/slab.h>
  16#include <linux/btrfs.h>
  17#include <linux/uio.h>
  18#include <linux/iversion.h>
  19#include <linux/fsverity.h>
  20#include "ctree.h"
  21#include "disk-io.h"
  22#include "transaction.h"
  23#include "btrfs_inode.h"
  24#include "print-tree.h"
  25#include "tree-log.h"
  26#include "locking.h"
  27#include "volumes.h"
  28#include "qgroup.h"
  29#include "compression.h"
  30#include "delalloc-space.h"
  31#include "reflink.h"
  32#include "subpage.h"
  33#include "fs.h"
  34#include "accessors.h"
  35#include "extent-tree.h"
  36#include "file-item.h"
  37#include "ioctl.h"
  38#include "file.h"
  39#include "super.h"
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  40
  41/* simple helper to fault in pages and copy.  This should go away
  42 * and be replaced with calls into generic code.
  43 */
  44static noinline int btrfs_copy_from_user(loff_t pos, size_t write_bytes,
  45					 struct page **prepared_pages,
  46					 struct iov_iter *i)
  47{
  48	size_t copied = 0;
  49	size_t total_copied = 0;
  50	int pg = 0;
  51	int offset = offset_in_page(pos);
  52
  53	while (write_bytes > 0) {
  54		size_t count = min_t(size_t,
  55				     PAGE_SIZE - offset, write_bytes);
  56		struct page *page = prepared_pages[pg];
  57		/*
  58		 * Copy data from userspace to the current page
  59		 */
  60		copied = copy_page_from_iter_atomic(page, offset, count, i);
  61
  62		/* Flush processor's dcache for this page */
  63		flush_dcache_page(page);
  64
  65		/*
  66		 * if we get a partial write, we can end up with
  67		 * partially up to date pages.  These add
  68		 * a lot of complexity, so make sure they don't
  69		 * happen by forcing this copy to be retried.
  70		 *
  71		 * The rest of the btrfs_file_write code will fall
  72		 * back to page at a time copies after we return 0.
  73		 */
  74		if (unlikely(copied < count)) {
  75			if (!PageUptodate(page)) {
  76				iov_iter_revert(i, copied);
  77				copied = 0;
  78			}
  79			if (!copied)
  80				break;
  81		}
  82
 
  83		write_bytes -= copied;
  84		total_copied += copied;
  85		offset += copied;
  86		if (offset == PAGE_SIZE) {
 
 
 
 
 
 
  87			pg++;
  88			offset = 0;
  89		}
  90	}
  91	return total_copied;
  92}
  93
  94/*
  95 * unlocks pages after btrfs_file_write is done with them
  96 */
  97static void btrfs_drop_pages(struct btrfs_fs_info *fs_info,
  98			     struct page **pages, size_t num_pages,
  99			     u64 pos, u64 copied)
 100{
 101	size_t i;
 102	u64 block_start = round_down(pos, fs_info->sectorsize);
 103	u64 block_len = round_up(pos + copied, fs_info->sectorsize) - block_start;
 104
 105	ASSERT(block_len <= U32_MAX);
 106	for (i = 0; i < num_pages; i++) {
 107		/* page checked is some magic around finding pages that
 108		 * have been modified without going through btrfs_set_page_dirty
 109		 * clear it here. There should be no need to mark the pages
 110		 * accessed as prepare_pages should have marked them accessed
 111		 * in prepare_pages via find_or_create_page()
 112		 */
 113		btrfs_page_clamp_clear_checked(fs_info, pages[i], block_start,
 114					       block_len);
 115		unlock_page(pages[i]);
 116		put_page(pages[i]);
 117	}
 118}
 119
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 120/*
 121 * After btrfs_copy_from_user(), update the following things for delalloc:
 122 * - Mark newly dirtied pages as DELALLOC in the io tree.
 123 *   Used to advise which range is to be written back.
 124 * - Mark modified pages as Uptodate/Dirty and not needing COW fixup
 125 * - Update inode size for past EOF write
 
 126 */
 127int btrfs_dirty_pages(struct btrfs_inode *inode, struct page **pages,
 128		      size_t num_pages, loff_t pos, size_t write_bytes,
 129		      struct extent_state **cached, bool noreserve)
 130{
 131	struct btrfs_fs_info *fs_info = inode->root->fs_info;
 132	int err = 0;
 133	int i;
 134	u64 num_bytes;
 135	u64 start_pos;
 136	u64 end_of_last_block;
 137	u64 end_pos = pos + write_bytes;
 138	loff_t isize = i_size_read(&inode->vfs_inode);
 139	unsigned int extra_bits = 0;
 140
 141	if (write_bytes == 0)
 142		return 0;
 143
 144	if (noreserve)
 145		extra_bits |= EXTENT_NORESERVE;
 146
 147	start_pos = round_down(pos, fs_info->sectorsize);
 148	num_bytes = round_up(write_bytes + pos - start_pos,
 149			     fs_info->sectorsize);
 150	ASSERT(num_bytes <= U32_MAX);
 151
 152	end_of_last_block = start_pos + num_bytes - 1;
 153
 154	/*
 155	 * The pages may have already been dirty, clear out old accounting so
 156	 * we can set things up properly
 157	 */
 158	clear_extent_bit(&inode->io_tree, start_pos, end_of_last_block,
 159			 EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
 160			 cached);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 161
 162	err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
 163					extra_bits, cached);
 164	if (err)
 165		return err;
 166
 167	for (i = 0; i < num_pages; i++) {
 168		struct page *p = pages[i];
 169
 170		btrfs_page_clamp_set_uptodate(fs_info, p, start_pos, num_bytes);
 171		btrfs_page_clamp_clear_checked(fs_info, p, start_pos, num_bytes);
 172		btrfs_page_clamp_set_dirty(fs_info, p, start_pos, num_bytes);
 173	}
 174
 175	/*
 176	 * we've only changed i_size in ram, and we haven't updated
 177	 * the disk i_size.  There is no need to log the inode
 178	 * at this time.
 179	 */
 180	if (end_pos > isize)
 181		i_size_write(&inode->vfs_inode, end_pos);
 182	return 0;
 183}
 184
 185/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 186 * this is very complex, but the basic idea is to drop all extents
 187 * in the range start - end.  hint_block is filled in with a block number
 188 * that would be a good hint to the block allocator for this file.
 189 *
 190 * If an extent intersects the range but is not entirely inside the range
 191 * it is either truncated or split.  Anything entirely inside the range
 192 * is deleted from the tree.
 193 *
 194 * Note: the VFS' inode number of bytes is not updated, it's up to the caller
 195 * to deal with that. We set the field 'bytes_found' of the arguments structure
 196 * with the number of allocated bytes found in the target range, so that the
 197 * caller can update the inode's number of bytes in an atomic way when
 198 * replacing extents in a range to avoid races with stat(2).
 199 */
 200int btrfs_drop_extents(struct btrfs_trans_handle *trans,
 201		       struct btrfs_root *root, struct btrfs_inode *inode,
 202		       struct btrfs_drop_extents_args *args)
 
 
 
 
 203{
 204	struct btrfs_fs_info *fs_info = root->fs_info;
 205	struct extent_buffer *leaf;
 206	struct btrfs_file_extent_item *fi;
 207	struct btrfs_ref ref = { 0 };
 208	struct btrfs_key key;
 209	struct btrfs_key new_key;
 
 210	u64 ino = btrfs_ino(inode);
 211	u64 search_start = args->start;
 212	u64 disk_bytenr = 0;
 213	u64 num_bytes = 0;
 214	u64 extent_offset = 0;
 215	u64 extent_end = 0;
 216	u64 last_end = args->start;
 217	int del_nr = 0;
 218	int del_slot = 0;
 219	int extent_type;
 220	int recow;
 221	int ret;
 222	int modify_tree = -1;
 223	int update_refs;
 224	int found = 0;
 225	struct btrfs_path *path = args->path;
 226
 227	args->bytes_found = 0;
 228	args->extent_inserted = false;
 229
 230	/* Must always have a path if ->replace_extent is true */
 231	ASSERT(!(args->replace_extent && !args->path));
 232
 233	if (!path) {
 234		path = btrfs_alloc_path();
 235		if (!path) {
 236			ret = -ENOMEM;
 237			goto out;
 238		}
 239	}
 240
 241	if (args->drop_cache)
 242		btrfs_drop_extent_map_range(inode, args->start, args->end - 1, false);
 243
 244	if (args->start >= inode->disk_i_size && !args->replace_extent)
 245		modify_tree = 0;
 246
 247	update_refs = (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID);
 
 248	while (1) {
 249		recow = 0;
 250		ret = btrfs_lookup_file_extent(trans, root, path, ino,
 251					       search_start, modify_tree);
 252		if (ret < 0)
 253			break;
 254		if (ret > 0 && path->slots[0] > 0 && search_start == args->start) {
 255			leaf = path->nodes[0];
 256			btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
 257			if (key.objectid == ino &&
 258			    key.type == BTRFS_EXTENT_DATA_KEY)
 259				path->slots[0]--;
 260		}
 261		ret = 0;
 
 262next_slot:
 263		leaf = path->nodes[0];
 264		if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 265			BUG_ON(del_nr > 0);
 266			ret = btrfs_next_leaf(root, path);
 267			if (ret < 0)
 268				break;
 269			if (ret > 0) {
 270				ret = 0;
 271				break;
 272			}
 
 273			leaf = path->nodes[0];
 274			recow = 1;
 275		}
 276
 277		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 278
 279		if (key.objectid > ino)
 280			break;
 281		if (WARN_ON_ONCE(key.objectid < ino) ||
 282		    key.type < BTRFS_EXTENT_DATA_KEY) {
 283			ASSERT(del_nr == 0);
 284			path->slots[0]++;
 285			goto next_slot;
 286		}
 287		if (key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= args->end)
 288			break;
 289
 290		fi = btrfs_item_ptr(leaf, path->slots[0],
 291				    struct btrfs_file_extent_item);
 292		extent_type = btrfs_file_extent_type(leaf, fi);
 293
 294		if (extent_type == BTRFS_FILE_EXTENT_REG ||
 295		    extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
 296			disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
 297			num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
 298			extent_offset = btrfs_file_extent_offset(leaf, fi);
 299			extent_end = key.offset +
 300				btrfs_file_extent_num_bytes(leaf, fi);
 301		} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 302			extent_end = key.offset +
 303				btrfs_file_extent_ram_bytes(leaf, fi);
 304		} else {
 305			/* can't happen */
 306			BUG();
 307		}
 308
 309		/*
 310		 * Don't skip extent items representing 0 byte lengths. They
 311		 * used to be created (bug) if while punching holes we hit
 312		 * -ENOSPC condition. So if we find one here, just ensure we
 313		 * delete it, otherwise we would insert a new file extent item
 314		 * with the same key (offset) as that 0 bytes length file
 315		 * extent item in the call to setup_items_for_insert() later
 316		 * in this function.
 317		 */
 318		if (extent_end == key.offset && extent_end >= search_start) {
 319			last_end = extent_end;
 320			goto delete_extent_item;
 321		}
 322
 323		if (extent_end <= search_start) {
 324			path->slots[0]++;
 325			goto next_slot;
 326		}
 327
 328		found = 1;
 329		search_start = max(key.offset, args->start);
 330		if (recow || !modify_tree) {
 331			modify_tree = -1;
 332			btrfs_release_path(path);
 333			continue;
 334		}
 335
 336		/*
 337		 *     | - range to drop - |
 338		 *  | -------- extent -------- |
 339		 */
 340		if (args->start > key.offset && args->end < extent_end) {
 341			BUG_ON(del_nr > 0);
 342			if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 343				ret = -EOPNOTSUPP;
 344				break;
 345			}
 346
 347			memcpy(&new_key, &key, sizeof(new_key));
 348			new_key.offset = args->start;
 349			ret = btrfs_duplicate_item(trans, root, path,
 350						   &new_key);
 351			if (ret == -EAGAIN) {
 352				btrfs_release_path(path);
 353				continue;
 354			}
 355			if (ret < 0)
 356				break;
 357
 358			leaf = path->nodes[0];
 359			fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
 360					    struct btrfs_file_extent_item);
 361			btrfs_set_file_extent_num_bytes(leaf, fi,
 362							args->start - key.offset);
 363
 364			fi = btrfs_item_ptr(leaf, path->slots[0],
 365					    struct btrfs_file_extent_item);
 366
 367			extent_offset += args->start - key.offset;
 368			btrfs_set_file_extent_offset(leaf, fi, extent_offset);
 369			btrfs_set_file_extent_num_bytes(leaf, fi,
 370							extent_end - args->start);
 371			btrfs_mark_buffer_dirty(leaf);
 372
 373			if (update_refs && disk_bytenr > 0) {
 374				btrfs_init_generic_ref(&ref,
 375						BTRFS_ADD_DELAYED_REF,
 376						disk_bytenr, num_bytes, 0);
 377				btrfs_init_data_ref(&ref,
 378						root->root_key.objectid,
 379						new_key.objectid,
 380						args->start - extent_offset,
 381						0, false);
 382				ret = btrfs_inc_extent_ref(trans, &ref);
 383				if (ret) {
 384					btrfs_abort_transaction(trans, ret);
 385					break;
 386				}
 387			}
 388			key.offset = args->start;
 389		}
 390		/*
 391		 * From here on out we will have actually dropped something, so
 392		 * last_end can be updated.
 393		 */
 394		last_end = extent_end;
 395
 396		/*
 397		 *  | ---- range to drop ----- |
 398		 *      | -------- extent -------- |
 399		 */
 400		if (args->start <= key.offset && args->end < extent_end) {
 401			if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 402				ret = -EOPNOTSUPP;
 403				break;
 404			}
 405
 406			memcpy(&new_key, &key, sizeof(new_key));
 407			new_key.offset = args->end;
 408			btrfs_set_item_key_safe(fs_info, path, &new_key);
 409
 410			extent_offset += args->end - key.offset;
 411			btrfs_set_file_extent_offset(leaf, fi, extent_offset);
 412			btrfs_set_file_extent_num_bytes(leaf, fi,
 413							extent_end - args->end);
 414			btrfs_mark_buffer_dirty(leaf);
 415			if (update_refs && disk_bytenr > 0)
 416				args->bytes_found += args->end - key.offset;
 417			break;
 418		}
 419
 420		search_start = extent_end;
 421		/*
 422		 *       | ---- range to drop ----- |
 423		 *  | -------- extent -------- |
 424		 */
 425		if (args->start > key.offset && args->end >= extent_end) {
 426			BUG_ON(del_nr > 0);
 427			if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 428				ret = -EOPNOTSUPP;
 429				break;
 430			}
 431
 432			btrfs_set_file_extent_num_bytes(leaf, fi,
 433							args->start - key.offset);
 434			btrfs_mark_buffer_dirty(leaf);
 435			if (update_refs && disk_bytenr > 0)
 436				args->bytes_found += extent_end - args->start;
 437			if (args->end == extent_end)
 438				break;
 439
 440			path->slots[0]++;
 441			goto next_slot;
 442		}
 443
 444		/*
 445		 *  | ---- range to drop ----- |
 446		 *    | ------ extent ------ |
 447		 */
 448		if (args->start <= key.offset && args->end >= extent_end) {
 449delete_extent_item:
 450			if (del_nr == 0) {
 451				del_slot = path->slots[0];
 452				del_nr = 1;
 453			} else {
 454				BUG_ON(del_slot + del_nr != path->slots[0]);
 455				del_nr++;
 456			}
 457
 458			if (update_refs &&
 459			    extent_type == BTRFS_FILE_EXTENT_INLINE) {
 460				args->bytes_found += extent_end - key.offset;
 
 461				extent_end = ALIGN(extent_end,
 462						   fs_info->sectorsize);
 463			} else if (update_refs && disk_bytenr > 0) {
 464				btrfs_init_generic_ref(&ref,
 465						BTRFS_DROP_DELAYED_REF,
 466						disk_bytenr, num_bytes, 0);
 467				btrfs_init_data_ref(&ref,
 468						root->root_key.objectid,
 469						key.objectid,
 470						key.offset - extent_offset, 0,
 471						false);
 472				ret = btrfs_free_extent(trans, &ref);
 473				if (ret) {
 474					btrfs_abort_transaction(trans, ret);
 475					break;
 476				}
 477				args->bytes_found += extent_end - key.offset;
 478			}
 479
 480			if (args->end == extent_end)
 481				break;
 482
 483			if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
 484				path->slots[0]++;
 485				goto next_slot;
 486			}
 487
 488			ret = btrfs_del_items(trans, root, path, del_slot,
 489					      del_nr);
 490			if (ret) {
 491				btrfs_abort_transaction(trans, ret);
 492				break;
 493			}
 494
 495			del_nr = 0;
 496			del_slot = 0;
 497
 498			btrfs_release_path(path);
 499			continue;
 500		}
 501
 502		BUG();
 503	}
 504
 505	if (!ret && del_nr > 0) {
 506		/*
 507		 * Set path->slots[0] to first slot, so that after the delete
 508		 * if items are move off from our leaf to its immediate left or
 509		 * right neighbor leafs, we end up with a correct and adjusted
 510		 * path->slots[0] for our insertion (if args->replace_extent).
 511		 */
 512		path->slots[0] = del_slot;
 513		ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
 514		if (ret)
 515			btrfs_abort_transaction(trans, ret);
 516	}
 517
 518	leaf = path->nodes[0];
 519	/*
 520	 * If btrfs_del_items() was called, it might have deleted a leaf, in
 521	 * which case it unlocked our path, so check path->locks[0] matches a
 522	 * write lock.
 523	 */
 524	if (!ret && args->replace_extent &&
 525	    path->locks[0] == BTRFS_WRITE_LOCK &&
 
 526	    btrfs_leaf_free_space(leaf) >=
 527	    sizeof(struct btrfs_item) + args->extent_item_size) {
 528
 529		key.objectid = ino;
 530		key.type = BTRFS_EXTENT_DATA_KEY;
 531		key.offset = args->start;
 532		if (!del_nr && path->slots[0] < btrfs_header_nritems(leaf)) {
 533			struct btrfs_key slot_key;
 534
 535			btrfs_item_key_to_cpu(leaf, &slot_key, path->slots[0]);
 536			if (btrfs_comp_cpu_keys(&key, &slot_key) > 0)
 537				path->slots[0]++;
 538		}
 539		btrfs_setup_item_for_insert(root, path, &key, args->extent_item_size);
 540		args->extent_inserted = true;
 
 
 
 
 541	}
 542
 543	if (!args->path)
 544		btrfs_free_path(path);
 545	else if (!args->extent_inserted)
 546		btrfs_release_path(path);
 547out:
 548	args->drop_end = found ? min(args->end, last_end) : args->end;
 
 
 
 
 
 
 
 
 
 549
 
 
 
 
 
 
 550	return ret;
 551}
 552
 553static int extent_mergeable(struct extent_buffer *leaf, int slot,
 554			    u64 objectid, u64 bytenr, u64 orig_offset,
 555			    u64 *start, u64 *end)
 556{
 557	struct btrfs_file_extent_item *fi;
 558	struct btrfs_key key;
 559	u64 extent_end;
 560
 561	if (slot < 0 || slot >= btrfs_header_nritems(leaf))
 562		return 0;
 563
 564	btrfs_item_key_to_cpu(leaf, &key, slot);
 565	if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
 566		return 0;
 567
 568	fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
 569	if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
 570	    btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
 571	    btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
 572	    btrfs_file_extent_compression(leaf, fi) ||
 573	    btrfs_file_extent_encryption(leaf, fi) ||
 574	    btrfs_file_extent_other_encoding(leaf, fi))
 575		return 0;
 576
 577	extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
 578	if ((*start && *start != key.offset) || (*end && *end != extent_end))
 579		return 0;
 580
 581	*start = key.offset;
 582	*end = extent_end;
 583	return 1;
 584}
 585
 586/*
 587 * Mark extent in the range start - end as written.
 588 *
 589 * This changes extent type from 'pre-allocated' to 'regular'. If only
 590 * part of extent is marked as written, the extent will be split into
 591 * two or three.
 592 */
 593int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
 594			      struct btrfs_inode *inode, u64 start, u64 end)
 595{
 596	struct btrfs_fs_info *fs_info = trans->fs_info;
 597	struct btrfs_root *root = inode->root;
 598	struct extent_buffer *leaf;
 599	struct btrfs_path *path;
 600	struct btrfs_file_extent_item *fi;
 601	struct btrfs_ref ref = { 0 };
 602	struct btrfs_key key;
 603	struct btrfs_key new_key;
 604	u64 bytenr;
 605	u64 num_bytes;
 606	u64 extent_end;
 607	u64 orig_offset;
 608	u64 other_start;
 609	u64 other_end;
 610	u64 split;
 611	int del_nr = 0;
 612	int del_slot = 0;
 613	int recow;
 614	int ret = 0;
 615	u64 ino = btrfs_ino(inode);
 616
 617	path = btrfs_alloc_path();
 618	if (!path)
 619		return -ENOMEM;
 620again:
 621	recow = 0;
 622	split = start;
 623	key.objectid = ino;
 624	key.type = BTRFS_EXTENT_DATA_KEY;
 625	key.offset = split;
 626
 627	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 628	if (ret < 0)
 629		goto out;
 630	if (ret > 0 && path->slots[0] > 0)
 631		path->slots[0]--;
 632
 633	leaf = path->nodes[0];
 634	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 635	if (key.objectid != ino ||
 636	    key.type != BTRFS_EXTENT_DATA_KEY) {
 637		ret = -EINVAL;
 638		btrfs_abort_transaction(trans, ret);
 639		goto out;
 640	}
 641	fi = btrfs_item_ptr(leaf, path->slots[0],
 642			    struct btrfs_file_extent_item);
 643	if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_PREALLOC) {
 644		ret = -EINVAL;
 645		btrfs_abort_transaction(trans, ret);
 646		goto out;
 647	}
 648	extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
 649	if (key.offset > start || extent_end < end) {
 650		ret = -EINVAL;
 651		btrfs_abort_transaction(trans, ret);
 652		goto out;
 653	}
 654
 655	bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
 656	num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
 657	orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
 658	memcpy(&new_key, &key, sizeof(new_key));
 659
 660	if (start == key.offset && end < extent_end) {
 661		other_start = 0;
 662		other_end = start;
 663		if (extent_mergeable(leaf, path->slots[0] - 1,
 664				     ino, bytenr, orig_offset,
 665				     &other_start, &other_end)) {
 666			new_key.offset = end;
 667			btrfs_set_item_key_safe(fs_info, path, &new_key);
 668			fi = btrfs_item_ptr(leaf, path->slots[0],
 669					    struct btrfs_file_extent_item);
 670			btrfs_set_file_extent_generation(leaf, fi,
 671							 trans->transid);
 672			btrfs_set_file_extent_num_bytes(leaf, fi,
 673							extent_end - end);
 674			btrfs_set_file_extent_offset(leaf, fi,
 675						     end - orig_offset);
 676			fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
 677					    struct btrfs_file_extent_item);
 678			btrfs_set_file_extent_generation(leaf, fi,
 679							 trans->transid);
 680			btrfs_set_file_extent_num_bytes(leaf, fi,
 681							end - other_start);
 682			btrfs_mark_buffer_dirty(leaf);
 683			goto out;
 684		}
 685	}
 686
 687	if (start > key.offset && end == extent_end) {
 688		other_start = end;
 689		other_end = 0;
 690		if (extent_mergeable(leaf, path->slots[0] + 1,
 691				     ino, bytenr, orig_offset,
 692				     &other_start, &other_end)) {
 693			fi = btrfs_item_ptr(leaf, path->slots[0],
 694					    struct btrfs_file_extent_item);
 695			btrfs_set_file_extent_num_bytes(leaf, fi,
 696							start - key.offset);
 697			btrfs_set_file_extent_generation(leaf, fi,
 698							 trans->transid);
 699			path->slots[0]++;
 700			new_key.offset = start;
 701			btrfs_set_item_key_safe(fs_info, path, &new_key);
 702
 703			fi = btrfs_item_ptr(leaf, path->slots[0],
 704					    struct btrfs_file_extent_item);
 705			btrfs_set_file_extent_generation(leaf, fi,
 706							 trans->transid);
 707			btrfs_set_file_extent_num_bytes(leaf, fi,
 708							other_end - start);
 709			btrfs_set_file_extent_offset(leaf, fi,
 710						     start - orig_offset);
 711			btrfs_mark_buffer_dirty(leaf);
 712			goto out;
 713		}
 714	}
 715
 716	while (start > key.offset || end < extent_end) {
 717		if (key.offset == start)
 718			split = end;
 719
 720		new_key.offset = split;
 721		ret = btrfs_duplicate_item(trans, root, path, &new_key);
 722		if (ret == -EAGAIN) {
 723			btrfs_release_path(path);
 724			goto again;
 725		}
 726		if (ret < 0) {
 727			btrfs_abort_transaction(trans, ret);
 728			goto out;
 729		}
 730
 731		leaf = path->nodes[0];
 732		fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
 733				    struct btrfs_file_extent_item);
 734		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
 735		btrfs_set_file_extent_num_bytes(leaf, fi,
 736						split - key.offset);
 737
 738		fi = btrfs_item_ptr(leaf, path->slots[0],
 739				    struct btrfs_file_extent_item);
 740
 741		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
 742		btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
 743		btrfs_set_file_extent_num_bytes(leaf, fi,
 744						extent_end - split);
 745		btrfs_mark_buffer_dirty(leaf);
 746
 747		btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, bytenr,
 748				       num_bytes, 0);
 749		btrfs_init_data_ref(&ref, root->root_key.objectid, ino,
 750				    orig_offset, 0, false);
 751		ret = btrfs_inc_extent_ref(trans, &ref);
 752		if (ret) {
 753			btrfs_abort_transaction(trans, ret);
 754			goto out;
 755		}
 756
 757		if (split == start) {
 758			key.offset = start;
 759		} else {
 760			if (start != key.offset) {
 761				ret = -EINVAL;
 762				btrfs_abort_transaction(trans, ret);
 763				goto out;
 764			}
 765			path->slots[0]--;
 766			extent_end = end;
 767		}
 768		recow = 1;
 769	}
 770
 771	other_start = end;
 772	other_end = 0;
 773	btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
 774			       num_bytes, 0);
 775	btrfs_init_data_ref(&ref, root->root_key.objectid, ino, orig_offset,
 776			    0, false);
 777	if (extent_mergeable(leaf, path->slots[0] + 1,
 778			     ino, bytenr, orig_offset,
 779			     &other_start, &other_end)) {
 780		if (recow) {
 781			btrfs_release_path(path);
 782			goto again;
 783		}
 784		extent_end = other_end;
 785		del_slot = path->slots[0] + 1;
 786		del_nr++;
 787		ret = btrfs_free_extent(trans, &ref);
 788		if (ret) {
 789			btrfs_abort_transaction(trans, ret);
 790			goto out;
 791		}
 792	}
 793	other_start = 0;
 794	other_end = start;
 795	if (extent_mergeable(leaf, path->slots[0] - 1,
 796			     ino, bytenr, orig_offset,
 797			     &other_start, &other_end)) {
 798		if (recow) {
 799			btrfs_release_path(path);
 800			goto again;
 801		}
 802		key.offset = other_start;
 803		del_slot = path->slots[0];
 804		del_nr++;
 805		ret = btrfs_free_extent(trans, &ref);
 806		if (ret) {
 807			btrfs_abort_transaction(trans, ret);
 808			goto out;
 809		}
 810	}
 811	if (del_nr == 0) {
 812		fi = btrfs_item_ptr(leaf, path->slots[0],
 813			   struct btrfs_file_extent_item);
 814		btrfs_set_file_extent_type(leaf, fi,
 815					   BTRFS_FILE_EXTENT_REG);
 816		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
 817		btrfs_mark_buffer_dirty(leaf);
 818	} else {
 819		fi = btrfs_item_ptr(leaf, del_slot - 1,
 820			   struct btrfs_file_extent_item);
 821		btrfs_set_file_extent_type(leaf, fi,
 822					   BTRFS_FILE_EXTENT_REG);
 823		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
 824		btrfs_set_file_extent_num_bytes(leaf, fi,
 825						extent_end - key.offset);
 826		btrfs_mark_buffer_dirty(leaf);
 827
 828		ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
 829		if (ret < 0) {
 830			btrfs_abort_transaction(trans, ret);
 831			goto out;
 832		}
 833	}
 834out:
 835	btrfs_free_path(path);
 836	return ret;
 837}
 838
 839/*
 840 * on error we return an unlocked page and the error value
 841 * on success we return a locked page and 0
 842 */
 843static int prepare_uptodate_page(struct inode *inode,
 844				 struct page *page, u64 pos,
 845				 bool force_uptodate)
 846{
 847	struct folio *folio = page_folio(page);
 848	int ret = 0;
 849
 850	if (((pos & (PAGE_SIZE - 1)) || force_uptodate) &&
 851	    !PageUptodate(page)) {
 852		ret = btrfs_read_folio(NULL, folio);
 853		if (ret)
 854			return ret;
 855		lock_page(page);
 856		if (!PageUptodate(page)) {
 857			unlock_page(page);
 858			return -EIO;
 859		}
 860
 861		/*
 862		 * Since btrfs_read_folio() will unlock the folio before it
 863		 * returns, there is a window where btrfs_release_folio() can be
 864		 * called to release the page.  Here we check both inode
 865		 * mapping and PagePrivate() to make sure the page was not
 866		 * released.
 867		 *
 868		 * The private flag check is essential for subpage as we need
 869		 * to store extra bitmap using page->private.
 870		 */
 871		if (page->mapping != inode->i_mapping || !PagePrivate(page)) {
 872			unlock_page(page);
 873			return -EAGAIN;
 874		}
 875	}
 876	return 0;
 877}
 878
 879static unsigned int get_prepare_fgp_flags(bool nowait)
 880{
 881	unsigned int fgp_flags = FGP_LOCK | FGP_ACCESSED | FGP_CREAT;
 882
 883	if (nowait)
 884		fgp_flags |= FGP_NOWAIT;
 885
 886	return fgp_flags;
 887}
 888
 889static gfp_t get_prepare_gfp_flags(struct inode *inode, bool nowait)
 890{
 891	gfp_t gfp;
 892
 893	gfp = btrfs_alloc_write_mask(inode->i_mapping);
 894	if (nowait) {
 895		gfp &= ~__GFP_DIRECT_RECLAIM;
 896		gfp |= GFP_NOWAIT;
 897	}
 898
 899	return gfp;
 900}
 901
 902/*
 903 * this just gets pages into the page cache and locks them down.
 904 */
 905static noinline int prepare_pages(struct inode *inode, struct page **pages,
 906				  size_t num_pages, loff_t pos,
 907				  size_t write_bytes, bool force_uptodate,
 908				  bool nowait)
 909{
 910	int i;
 911	unsigned long index = pos >> PAGE_SHIFT;
 912	gfp_t mask = get_prepare_gfp_flags(inode, nowait);
 913	unsigned int fgp_flags = get_prepare_fgp_flags(nowait);
 914	int err = 0;
 915	int faili;
 916
 917	for (i = 0; i < num_pages; i++) {
 918again:
 919		pages[i] = pagecache_get_page(inode->i_mapping, index + i,
 920					      fgp_flags, mask | __GFP_WRITE);
 921		if (!pages[i]) {
 922			faili = i - 1;
 923			if (nowait)
 924				err = -EAGAIN;
 925			else
 926				err = -ENOMEM;
 927			goto fail;
 928		}
 929
 930		err = set_page_extent_mapped(pages[i]);
 931		if (err < 0) {
 932			faili = i;
 933			goto fail;
 934		}
 935
 936		if (i == 0)
 937			err = prepare_uptodate_page(inode, pages[i], pos,
 938						    force_uptodate);
 939		if (!err && i == num_pages - 1)
 940			err = prepare_uptodate_page(inode, pages[i],
 941						    pos + write_bytes, false);
 942		if (err) {
 943			put_page(pages[i]);
 944			if (!nowait && err == -EAGAIN) {
 945				err = 0;
 946				goto again;
 947			}
 948			faili = i - 1;
 949			goto fail;
 950		}
 951		wait_on_page_writeback(pages[i]);
 952	}
 953
 954	return 0;
 955fail:
 956	while (faili >= 0) {
 957		unlock_page(pages[faili]);
 958		put_page(pages[faili]);
 959		faili--;
 960	}
 961	return err;
 962
 963}
 964
 965/*
 966 * This function locks the extent and properly waits for data=ordered extents
 967 * to finish before allowing the pages to be modified if need.
 968 *
 969 * The return value:
 970 * 1 - the extent is locked
 971 * 0 - the extent is not locked, and everything is OK
 972 * -EAGAIN - need re-prepare the pages
 973 * the other < 0 number - Something wrong happens
 974 */
 975static noinline int
 976lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct page **pages,
 977				size_t num_pages, loff_t pos,
 978				size_t write_bytes,
 979				u64 *lockstart, u64 *lockend, bool nowait,
 980				struct extent_state **cached_state)
 981{
 982	struct btrfs_fs_info *fs_info = inode->root->fs_info;
 983	u64 start_pos;
 984	u64 last_pos;
 985	int i;
 986	int ret = 0;
 987
 988	start_pos = round_down(pos, fs_info->sectorsize);
 989	last_pos = round_up(pos + write_bytes, fs_info->sectorsize) - 1;
 
 
 990
 991	if (start_pos < inode->vfs_inode.i_size) {
 992		struct btrfs_ordered_extent *ordered;
 993
 994		if (nowait) {
 995			if (!try_lock_extent(&inode->io_tree, start_pos, last_pos,
 996					     cached_state)) {
 997				for (i = 0; i < num_pages; i++) {
 998					unlock_page(pages[i]);
 999					put_page(pages[i]);
1000					pages[i] = NULL;
1001				}
1002
1003				return -EAGAIN;
1004			}
1005		} else {
1006			lock_extent(&inode->io_tree, start_pos, last_pos, cached_state);
1007		}
1008
1009		ordered = btrfs_lookup_ordered_range(inode, start_pos,
1010						     last_pos - start_pos + 1);
1011		if (ordered &&
1012		    ordered->file_offset + ordered->num_bytes > start_pos &&
1013		    ordered->file_offset <= last_pos) {
1014			unlock_extent(&inode->io_tree, start_pos, last_pos,
1015				      cached_state);
1016			for (i = 0; i < num_pages; i++) {
1017				unlock_page(pages[i]);
1018				put_page(pages[i]);
1019			}
1020			btrfs_start_ordered_extent(ordered, 1);
 
1021			btrfs_put_ordered_extent(ordered);
1022			return -EAGAIN;
1023		}
1024		if (ordered)
1025			btrfs_put_ordered_extent(ordered);
1026
1027		*lockstart = start_pos;
1028		*lockend = last_pos;
1029		ret = 1;
1030	}
1031
1032	/*
1033	 * We should be called after prepare_pages() which should have locked
1034	 * all pages in the range.
 
 
 
 
 
 
 
 
 
 
1035	 */
1036	for (i = 0; i < num_pages; i++)
 
1037		WARN_ON(!PageLocked(pages[i]));
 
1038
1039	return ret;
1040}
1041
1042/*
1043 * Check if we can do nocow write into the range [@pos, @pos + @write_bytes)
1044 *
1045 * @pos:         File offset.
1046 * @write_bytes: The length to write, will be updated to the nocow writeable
1047 *               range.
1048 *
1049 * This function will flush ordered extents in the range to ensure proper
1050 * nocow checks.
1051 *
1052 * Return:
1053 * > 0          If we can nocow, and updates @write_bytes.
1054 *  0           If we can't do a nocow write.
1055 * -EAGAIN      If we can't do a nocow write because snapshoting of the inode's
1056 *              root is in progress.
1057 * < 0          If an error happened.
1058 *
1059 * NOTE: Callers need to call btrfs_check_nocow_unlock() if we return > 0.
1060 */
1061int btrfs_check_nocow_lock(struct btrfs_inode *inode, loff_t pos,
1062			   size_t *write_bytes, bool nowait)
1063{
1064	struct btrfs_fs_info *fs_info = inode->root->fs_info;
1065	struct btrfs_root *root = inode->root;
1066	struct extent_state *cached_state = NULL;
1067	u64 lockstart, lockend;
1068	u64 num_bytes;
1069	int ret;
1070
1071	if (!(inode->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC)))
1072		return 0;
1073
1074	if (!btrfs_drew_try_write_lock(&root->snapshot_lock))
1075		return -EAGAIN;
1076
1077	lockstart = round_down(pos, fs_info->sectorsize);
1078	lockend = round_up(pos + *write_bytes,
1079			   fs_info->sectorsize) - 1;
1080	num_bytes = lockend - lockstart + 1;
1081
1082	if (nowait) {
1083		if (!btrfs_try_lock_ordered_range(inode, lockstart, lockend,
1084						  &cached_state)) {
1085			btrfs_drew_write_unlock(&root->snapshot_lock);
1086			return -EAGAIN;
 
 
 
 
 
 
 
1087		}
1088	} else {
1089		btrfs_lock_and_flush_ordered_range(inode, lockstart, lockend,
1090						   &cached_state);
1091	}
 
1092	ret = can_nocow_extent(&inode->vfs_inode, lockstart, &num_bytes,
1093			NULL, NULL, NULL, nowait, false);
1094	if (ret <= 0)
1095		btrfs_drew_write_unlock(&root->snapshot_lock);
1096	else
 
 
1097		*write_bytes = min_t(size_t, *write_bytes ,
1098				     num_bytes - pos + lockstart);
1099	unlock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
 
 
1100
1101	return ret;
1102}
1103
1104void btrfs_check_nocow_unlock(struct btrfs_inode *inode)
 
1105{
1106	btrfs_drew_write_unlock(&inode->root->snapshot_lock);
1107}
1108
1109static void update_time_for_write(struct inode *inode)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1110{
1111	struct timespec64 now;
1112
1113	if (IS_NOCMTIME(inode))
1114		return;
1115
1116	now = current_time(inode);
1117	if (!timespec64_equal(&inode->i_mtime, &now))
1118		inode->i_mtime = now;
1119
1120	if (!timespec64_equal(&inode->i_ctime, &now))
1121		inode->i_ctime = now;
1122
1123	if (IS_I_VERSION(inode))
1124		inode_inc_iversion(inode);
1125}
1126
1127static int btrfs_write_check(struct kiocb *iocb, struct iov_iter *from,
1128			     size_t count)
1129{
1130	struct file *file = iocb->ki_filp;
1131	struct inode *inode = file_inode(file);
1132	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1133	loff_t pos = iocb->ki_pos;
1134	int ret;
1135	loff_t oldsize;
1136	loff_t start_pos;
1137
1138	/*
1139	 * Quickly bail out on NOWAIT writes if we don't have the nodatacow or
1140	 * prealloc flags, as without those flags we always have to COW. We will
1141	 * later check if we can really COW into the target range (using
1142	 * can_nocow_extent() at btrfs_get_blocks_direct_write()).
1143	 */
1144	if ((iocb->ki_flags & IOCB_NOWAIT) &&
1145	    !(BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC)))
1146		return -EAGAIN;
1147
1148	current->backing_dev_info = inode_to_bdi(inode);
1149	ret = file_remove_privs(file);
1150	if (ret)
1151		return ret;
1152
1153	/*
1154	 * We reserve space for updating the inode when we reserve space for the
1155	 * extent we are going to write, so we will enospc out there.  We don't
1156	 * need to start yet another transaction to update the inode as we will
1157	 * update the inode when we finish writing whatever data we write.
1158	 */
1159	update_time_for_write(inode);
1160
1161	start_pos = round_down(pos, fs_info->sectorsize);
1162	oldsize = i_size_read(inode);
1163	if (start_pos > oldsize) {
1164		/* Expand hole size to cover write data, preventing empty gap */
1165		loff_t end_pos = round_up(pos + count, fs_info->sectorsize);
1166
1167		ret = btrfs_cont_expand(BTRFS_I(inode), oldsize, end_pos);
1168		if (ret) {
1169			current->backing_dev_info = NULL;
1170			return ret;
1171		}
1172	}
1173
1174	return 0;
1175}
1176
1177static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb,
1178					       struct iov_iter *i)
1179{
1180	struct file *file = iocb->ki_filp;
1181	loff_t pos;
1182	struct inode *inode = file_inode(file);
1183	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1184	struct page **pages = NULL;
1185	struct extent_changeset *data_reserved = NULL;
1186	u64 release_bytes = 0;
1187	u64 lockstart;
1188	u64 lockend;
1189	size_t num_written = 0;
1190	int nrptrs;
1191	ssize_t ret;
1192	bool only_release_metadata = false;
1193	bool force_page_uptodate = false;
1194	loff_t old_isize = i_size_read(inode);
1195	unsigned int ilock_flags = 0;
1196	const bool nowait = (iocb->ki_flags & IOCB_NOWAIT);
1197	unsigned int bdp_flags = (nowait ? BDP_ASYNC : 0);
1198
1199	if (nowait)
1200		ilock_flags |= BTRFS_ILOCK_TRY;
1201
1202	ret = btrfs_inode_lock(BTRFS_I(inode), ilock_flags);
1203	if (ret < 0)
1204		return ret;
1205
1206	ret = generic_write_checks(iocb, i);
1207	if (ret <= 0)
1208		goto out;
1209
1210	ret = btrfs_write_check(iocb, i, ret);
1211	if (ret < 0)
1212		goto out;
1213
1214	pos = iocb->ki_pos;
1215	nrptrs = min(DIV_ROUND_UP(iov_iter_count(i), PAGE_SIZE),
1216			PAGE_SIZE / (sizeof(struct page *)));
1217	nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
1218	nrptrs = max(nrptrs, 8);
1219	pages = kmalloc_array(nrptrs, sizeof(struct page *), GFP_KERNEL);
1220	if (!pages) {
1221		ret = -ENOMEM;
1222		goto out;
1223	}
1224
1225	while (iov_iter_count(i) > 0) {
1226		struct extent_state *cached_state = NULL;
1227		size_t offset = offset_in_page(pos);
1228		size_t sector_offset;
1229		size_t write_bytes = min(iov_iter_count(i),
1230					 nrptrs * (size_t)PAGE_SIZE -
1231					 offset);
1232		size_t num_pages;
 
1233		size_t reserve_bytes;
1234		size_t dirty_pages;
1235		size_t copied;
1236		size_t dirty_sectors;
1237		size_t num_sectors;
1238		int extents_locked;
1239
 
 
1240		/*
1241		 * Fault pages before locking them in prepare_pages
1242		 * to avoid recursive lock
1243		 */
1244		if (unlikely(fault_in_iov_iter_readable(i, write_bytes))) {
1245			ret = -EFAULT;
1246			break;
1247		}
1248
1249		only_release_metadata = false;
1250		sector_offset = pos & (fs_info->sectorsize - 1);
 
 
1251
1252		extent_changeset_release(data_reserved);
1253		ret = btrfs_check_data_free_space(BTRFS_I(inode),
1254						  &data_reserved, pos,
1255						  write_bytes, nowait);
1256		if (ret < 0) {
1257			int can_nocow;
1258
1259			if (nowait && (ret == -ENOSPC || ret == -EAGAIN)) {
1260				ret = -EAGAIN;
 
 
 
 
 
 
 
 
 
 
 
 
 
1261				break;
1262			}
1263
1264			/*
1265			 * If we don't have to COW at the offset, reserve
1266			 * metadata only. write_bytes may get smaller than
1267			 * requested here.
1268			 */
1269			can_nocow = btrfs_check_nocow_lock(BTRFS_I(inode), pos,
1270							   &write_bytes, nowait);
1271			if (can_nocow < 0)
1272				ret = can_nocow;
1273			if (can_nocow > 0)
1274				ret = 0;
1275			if (ret)
1276				break;
1277			only_release_metadata = true;
1278		}
1279
1280		num_pages = DIV_ROUND_UP(write_bytes + offset, PAGE_SIZE);
1281		WARN_ON(num_pages > nrptrs);
1282		reserve_bytes = round_up(write_bytes + sector_offset,
1283					 fs_info->sectorsize);
1284		WARN_ON(reserve_bytes == 0);
1285		ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
1286						      reserve_bytes,
1287						      reserve_bytes, nowait);
1288		if (ret) {
1289			if (!only_release_metadata)
1290				btrfs_free_reserved_data_space(BTRFS_I(inode),
1291						data_reserved, pos,
1292						write_bytes);
1293			else
1294				btrfs_check_nocow_unlock(BTRFS_I(inode));
1295
1296			if (nowait && ret == -ENOSPC)
1297				ret = -EAGAIN;
1298			break;
1299		}
1300
1301		release_bytes = reserve_bytes;
1302again:
1303		ret = balance_dirty_pages_ratelimited_flags(inode->i_mapping, bdp_flags);
1304		if (ret) {
1305			btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes);
1306			break;
1307		}
1308
1309		/*
1310		 * This is going to setup the pages array with the number of
1311		 * pages we want, so we don't really need to worry about the
1312		 * contents of pages from loop to loop
1313		 */
1314		ret = prepare_pages(inode, pages, num_pages,
1315				    pos, write_bytes, force_page_uptodate, false);
 
1316		if (ret) {
1317			btrfs_delalloc_release_extents(BTRFS_I(inode),
1318						       reserve_bytes);
1319			break;
1320		}
1321
1322		extents_locked = lock_and_cleanup_extent_if_need(
1323				BTRFS_I(inode), pages,
1324				num_pages, pos, write_bytes, &lockstart,
1325				&lockend, nowait, &cached_state);
1326		if (extents_locked < 0) {
1327			if (!nowait && extents_locked == -EAGAIN)
1328				goto again;
1329
1330			btrfs_delalloc_release_extents(BTRFS_I(inode),
1331						       reserve_bytes);
1332			ret = extents_locked;
1333			break;
1334		}
1335
1336		copied = btrfs_copy_from_user(pos, write_bytes, pages, i);
1337
1338		num_sectors = BTRFS_BYTES_TO_BLKS(fs_info, reserve_bytes);
1339		dirty_sectors = round_up(copied + sector_offset,
1340					fs_info->sectorsize);
1341		dirty_sectors = BTRFS_BYTES_TO_BLKS(fs_info, dirty_sectors);
1342
1343		/*
1344		 * if we have trouble faulting in the pages, fall
1345		 * back to one page at a time
1346		 */
1347		if (copied < write_bytes)
1348			nrptrs = 1;
1349
1350		if (copied == 0) {
1351			force_page_uptodate = true;
1352			dirty_sectors = 0;
1353			dirty_pages = 0;
1354		} else {
1355			force_page_uptodate = false;
1356			dirty_pages = DIV_ROUND_UP(copied + offset,
1357						   PAGE_SIZE);
1358		}
1359
1360		if (num_sectors > dirty_sectors) {
1361			/* release everything except the sectors we dirtied */
1362			release_bytes -= dirty_sectors << fs_info->sectorsize_bits;
 
1363			if (only_release_metadata) {
1364				btrfs_delalloc_release_metadata(BTRFS_I(inode),
1365							release_bytes, true);
1366			} else {
1367				u64 __pos;
1368
1369				__pos = round_down(pos,
1370						   fs_info->sectorsize) +
1371					(dirty_pages << PAGE_SHIFT);
1372				btrfs_delalloc_release_space(BTRFS_I(inode),
1373						data_reserved, __pos,
1374						release_bytes, true);
1375			}
1376		}
1377
1378		release_bytes = round_up(copied + sector_offset,
1379					fs_info->sectorsize);
1380
1381		ret = btrfs_dirty_pages(BTRFS_I(inode), pages,
1382					dirty_pages, pos, copied,
1383					&cached_state, only_release_metadata);
 
1384
1385		/*
1386		 * If we have not locked the extent range, because the range's
1387		 * start offset is >= i_size, we might still have a non-NULL
1388		 * cached extent state, acquired while marking the extent range
1389		 * as delalloc through btrfs_dirty_pages(). Therefore free any
1390		 * possible cached extent state to avoid a memory leak.
1391		 */
1392		if (extents_locked)
1393			unlock_extent(&BTRFS_I(inode)->io_tree, lockstart,
1394				      lockend, &cached_state);
1395		else
1396			free_extent_state(cached_state);
1397
1398		btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes);
1399		if (ret) {
1400			btrfs_drop_pages(fs_info, pages, num_pages, pos, copied);
1401			break;
1402		}
1403
1404		release_bytes = 0;
1405		if (only_release_metadata)
1406			btrfs_check_nocow_unlock(BTRFS_I(inode));
1407
1408		btrfs_drop_pages(fs_info, pages, num_pages, pos, copied);
 
 
 
 
 
 
 
 
 
 
 
1409
1410		cond_resched();
1411
 
 
1412		pos += copied;
1413		num_written += copied;
1414	}
1415
1416	kfree(pages);
1417
1418	if (release_bytes) {
1419		if (only_release_metadata) {
1420			btrfs_check_nocow_unlock(BTRFS_I(inode));
1421			btrfs_delalloc_release_metadata(BTRFS_I(inode),
1422					release_bytes, true);
1423		} else {
1424			btrfs_delalloc_release_space(BTRFS_I(inode),
1425					data_reserved,
1426					round_down(pos, fs_info->sectorsize),
1427					release_bytes, true);
1428		}
1429	}
1430
1431	extent_changeset_free(data_reserved);
1432	if (num_written > 0) {
1433		pagecache_isize_extended(inode, old_isize, iocb->ki_pos);
1434		iocb->ki_pos += num_written;
1435	}
1436out:
1437	btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
1438	return num_written ? num_written : ret;
1439}
1440
1441static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
1442			       const struct iov_iter *iter, loff_t offset)
1443{
1444	const u32 blocksize_mask = fs_info->sectorsize - 1;
1445
1446	if (offset & blocksize_mask)
1447		return -EINVAL;
1448
1449	if (iov_iter_alignment(iter) & blocksize_mask)
1450		return -EINVAL;
1451
1452	return 0;
1453}
1454
1455static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
1456{
1457	struct file *file = iocb->ki_filp;
1458	struct inode *inode = file_inode(file);
1459	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1460	loff_t pos;
1461	ssize_t written = 0;
1462	ssize_t written_buffered;
1463	size_t prev_left = 0;
1464	loff_t endbyte;
1465	ssize_t err;
1466	unsigned int ilock_flags = 0;
1467	struct iomap_dio *dio;
1468
1469	if (iocb->ki_flags & IOCB_NOWAIT)
1470		ilock_flags |= BTRFS_ILOCK_TRY;
1471
1472	/* If the write DIO is within EOF, use a shared lock */
1473	if (iocb->ki_pos + iov_iter_count(from) <= i_size_read(inode))
1474		ilock_flags |= BTRFS_ILOCK_SHARED;
1475
1476relock:
1477	err = btrfs_inode_lock(BTRFS_I(inode), ilock_flags);
1478	if (err < 0)
1479		return err;
1480
1481	err = generic_write_checks(iocb, from);
1482	if (err <= 0) {
1483		btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
1484		return err;
1485	}
1486
1487	err = btrfs_write_check(iocb, from, err);
1488	if (err < 0) {
1489		btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
1490		goto out;
1491	}
1492
1493	pos = iocb->ki_pos;
1494	/*
1495	 * Re-check since file size may have changed just before taking the
1496	 * lock or pos may have changed because of O_APPEND in generic_write_check()
1497	 */
1498	if ((ilock_flags & BTRFS_ILOCK_SHARED) &&
1499	    pos + iov_iter_count(from) > i_size_read(inode)) {
1500		btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
1501		ilock_flags &= ~BTRFS_ILOCK_SHARED;
1502		goto relock;
1503	}
1504
1505	if (check_direct_IO(fs_info, from, pos)) {
1506		btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
1507		goto buffered;
1508	}
1509
1510	/*
1511	 * The iov_iter can be mapped to the same file range we are writing to.
1512	 * If that's the case, then we will deadlock in the iomap code, because
1513	 * it first calls our callback btrfs_dio_iomap_begin(), which will create
1514	 * an ordered extent, and after that it will fault in the pages that the
1515	 * iov_iter refers to. During the fault in we end up in the readahead
1516	 * pages code (starting at btrfs_readahead()), which will lock the range,
1517	 * find that ordered extent and then wait for it to complete (at
1518	 * btrfs_lock_and_flush_ordered_range()), resulting in a deadlock since
1519	 * obviously the ordered extent can never complete as we didn't submit
1520	 * yet the respective bio(s). This always happens when the buffer is
1521	 * memory mapped to the same file range, since the iomap DIO code always
1522	 * invalidates pages in the target file range (after starting and waiting
1523	 * for any writeback).
1524	 *
1525	 * So here we disable page faults in the iov_iter and then retry if we
1526	 * got -EFAULT, faulting in the pages before the retry.
1527	 */
1528	from->nofault = true;
1529	dio = btrfs_dio_write(iocb, from, written);
1530	from->nofault = false;
1531
1532	/*
1533	 * iomap_dio_complete() will call btrfs_sync_file() if we have a dsync
1534	 * iocb, and that needs to lock the inode. So unlock it before calling
1535	 * iomap_dio_complete() to avoid a deadlock.
1536	 */
1537	btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
1538
1539	if (IS_ERR_OR_NULL(dio))
1540		err = PTR_ERR_OR_ZERO(dio);
1541	else
1542		err = iomap_dio_complete(dio);
1543
1544	/* No increment (+=) because iomap returns a cumulative value. */
1545	if (err > 0)
1546		written = err;
1547
1548	if (iov_iter_count(from) > 0 && (err == -EFAULT || err > 0)) {
1549		const size_t left = iov_iter_count(from);
1550		/*
1551		 * We have more data left to write. Try to fault in as many as
1552		 * possible of the remainder pages and retry. We do this without
1553		 * releasing and locking again the inode, to prevent races with
1554		 * truncate.
1555		 *
1556		 * Also, in case the iov refers to pages in the file range of the
1557		 * file we want to write to (due to a mmap), we could enter an
1558		 * infinite loop if we retry after faulting the pages in, since
1559		 * iomap will invalidate any pages in the range early on, before
1560		 * it tries to fault in the pages of the iov. So we keep track of
1561		 * how much was left of iov in the previous EFAULT and fallback
1562		 * to buffered IO in case we haven't made any progress.
1563		 */
1564		if (left == prev_left) {
1565			err = -ENOTBLK;
1566		} else {
1567			fault_in_iov_iter_readable(from, left);
1568			prev_left = left;
1569			goto relock;
1570		}
1571	}
1572
1573	/*
1574	 * If 'err' is -ENOTBLK or we have not written all data, then it means
1575	 * we must fallback to buffered IO.
1576	 */
1577	if ((err < 0 && err != -ENOTBLK) || !iov_iter_count(from))
1578		goto out;
1579
1580buffered:
1581	/*
1582	 * If we are in a NOWAIT context, then return -EAGAIN to signal the caller
1583	 * it must retry the operation in a context where blocking is acceptable,
1584	 * because even if we end up not blocking during the buffered IO attempt
1585	 * below, we will block when flushing and waiting for the IO.
1586	 */
1587	if (iocb->ki_flags & IOCB_NOWAIT) {
1588		err = -EAGAIN;
1589		goto out;
1590	}
1591
1592	pos = iocb->ki_pos;
1593	written_buffered = btrfs_buffered_write(iocb, from);
1594	if (written_buffered < 0) {
1595		err = written_buffered;
1596		goto out;
1597	}
1598	/*
1599	 * Ensure all data is persisted. We want the next direct IO read to be
1600	 * able to read what was just written.
1601	 */
1602	endbyte = pos + written_buffered - 1;
1603	err = btrfs_fdatawrite_range(inode, pos, endbyte);
1604	if (err)
1605		goto out;
1606	err = filemap_fdatawait_range(inode->i_mapping, pos, endbyte);
1607	if (err)
1608		goto out;
1609	written += written_buffered;
1610	iocb->ki_pos = pos + written_buffered;
1611	invalidate_mapping_pages(file->f_mapping, pos >> PAGE_SHIFT,
1612				 endbyte >> PAGE_SHIFT);
1613out:
1614	return err < 0 ? err : written;
1615}
1616
1617static ssize_t btrfs_encoded_write(struct kiocb *iocb, struct iov_iter *from,
1618			const struct btrfs_ioctl_encoded_io_args *encoded)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1619{
1620	struct file *file = iocb->ki_filp;
1621	struct inode *inode = file_inode(file);
1622	loff_t count;
1623	ssize_t ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
1624
1625	btrfs_inode_lock(BTRFS_I(inode), 0);
1626	count = encoded->len;
1627	ret = generic_write_checks_count(iocb, &count);
1628	if (ret == 0 && count != encoded->len) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1629		/*
1630		 * The write got truncated by generic_write_checks_count(). We
1631		 * can't do a partial encoded write.
 
1632		 */
1633		ret = -EFBIG;
 
 
 
1634	}
1635	if (ret || encoded->len == 0)
1636		goto out;
1637
1638	ret = btrfs_write_check(iocb, from, encoded->len);
1639	if (ret < 0)
 
 
1640		goto out;
 
1641
1642	ret = btrfs_do_encoded_write(iocb, from, encoded);
1643out:
1644	btrfs_inode_unlock(BTRFS_I(inode), 0);
1645	return ret;
1646}
1647
1648ssize_t btrfs_do_write_iter(struct kiocb *iocb, struct iov_iter *from,
1649			    const struct btrfs_ioctl_encoded_io_args *encoded)
1650{
1651	struct file *file = iocb->ki_filp;
1652	struct btrfs_inode *inode = BTRFS_I(file_inode(file));
1653	ssize_t num_written, num_sync;
1654	const bool sync = iocb_is_dsync(iocb);
1655
1656	/*
1657	 * If the fs flips readonly due to some impossible error, although we
1658	 * have opened a file as writable, we have to stop this write operation
1659	 * to ensure consistency.
 
1660	 */
1661	if (BTRFS_FS_ERROR(inode->root->fs_info))
1662		return -EROFS;
1663
1664	if (encoded && (iocb->ki_flags & IOCB_NOWAIT))
1665		return -EOPNOTSUPP;
 
 
 
 
 
 
 
 
 
 
 
 
1666
1667	if (sync)
1668		atomic_inc(&inode->sync_writers);
1669
1670	if (encoded) {
1671		num_written = btrfs_encoded_write(iocb, from, encoded);
1672		num_sync = encoded->len;
1673	} else if (iocb->ki_flags & IOCB_DIRECT) {
1674		num_written = btrfs_direct_write(iocb, from);
1675		num_sync = num_written;
1676	} else {
1677		num_written = btrfs_buffered_write(iocb, from);
1678		num_sync = num_written;
 
 
 
 
1679	}
1680
1681	btrfs_set_inode_last_sub_trans(inode);
1682
1683	if (num_sync > 0) {
1684		num_sync = generic_write_sync(iocb, num_sync);
1685		if (num_sync < 0)
1686			num_written = num_sync;
1687	}
 
 
 
 
 
1688
1689	if (sync)
1690		atomic_dec(&inode->sync_writers);
1691
1692	current->backing_dev_info = NULL;
1693	return num_written;
1694}
1695
1696static ssize_t btrfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
1697{
1698	return btrfs_do_write_iter(iocb, from, NULL);
1699}
1700
1701int btrfs_release_file(struct inode *inode, struct file *filp)
1702{
1703	struct btrfs_file_private *private = filp->private_data;
1704
1705	if (private) {
1706		kfree(private->filldir_buf);
1707		free_extent_state(private->llseek_cached_state);
1708		kfree(private);
1709		filp->private_data = NULL;
1710	}
1711
1712	/*
1713	 * Set by setattr when we are about to truncate a file from a non-zero
1714	 * size to a zero size.  This tries to flush down new bytes that may
1715	 * have been written if the application were using truncate to replace
1716	 * a file in place.
1717	 */
1718	if (test_and_clear_bit(BTRFS_INODE_FLUSH_ON_CLOSE,
1719			       &BTRFS_I(inode)->runtime_flags))
1720			filemap_flush(inode->i_mapping);
1721	return 0;
1722}
1723
1724static int start_ordered_ops(struct inode *inode, loff_t start, loff_t end)
1725{
1726	int ret;
1727	struct blk_plug plug;
1728
1729	/*
1730	 * This is only called in fsync, which would do synchronous writes, so
1731	 * a plug can merge adjacent IOs as much as possible.  Esp. in case of
1732	 * multiple disks using raid profile, a large IO can be split to
1733	 * several segments of stripe length (currently 64K).
1734	 */
1735	blk_start_plug(&plug);
1736	atomic_inc(&BTRFS_I(inode)->sync_writers);
1737	ret = btrfs_fdatawrite_range(inode, start, end);
1738	atomic_dec(&BTRFS_I(inode)->sync_writers);
1739	blk_finish_plug(&plug);
1740
1741	return ret;
1742}
1743
1744static inline bool skip_inode_logging(const struct btrfs_log_ctx *ctx)
1745{
1746	struct btrfs_inode *inode = BTRFS_I(ctx->inode);
1747	struct btrfs_fs_info *fs_info = inode->root->fs_info;
1748
1749	if (btrfs_inode_in_log(inode, fs_info->generation) &&
1750	    list_empty(&ctx->ordered_extents))
1751		return true;
1752
1753	/*
1754	 * If we are doing a fast fsync we can not bail out if the inode's
1755	 * last_trans is <= then the last committed transaction, because we only
1756	 * update the last_trans of the inode during ordered extent completion,
1757	 * and for a fast fsync we don't wait for that, we only wait for the
1758	 * writeback to complete.
1759	 */
1760	if (inode->last_trans <= fs_info->last_trans_committed &&
1761	    (test_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags) ||
1762	     list_empty(&ctx->ordered_extents)))
1763		return true;
1764
1765	return false;
1766}
1767
1768/*
1769 * fsync call for both files and directories.  This logs the inode into
1770 * the tree log instead of forcing full commits whenever possible.
1771 *
1772 * It needs to call filemap_fdatawait so that all ordered extent updates are
1773 * in the metadata btree are up to date for copying to the log.
1774 *
1775 * It drops the inode mutex before doing the tree log commit.  This is an
1776 * important optimization for directories because holding the mutex prevents
1777 * new operations on the dir while we write to disk.
1778 */
1779int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
1780{
1781	struct dentry *dentry = file_dentry(file);
1782	struct inode *inode = d_inode(dentry);
1783	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1784	struct btrfs_root *root = BTRFS_I(inode)->root;
1785	struct btrfs_trans_handle *trans;
1786	struct btrfs_log_ctx ctx;
1787	int ret = 0, err;
1788	u64 len;
1789	bool full_sync;
1790
1791	trace_btrfs_sync_file(file, datasync);
1792
1793	btrfs_init_log_ctx(&ctx, inode);
1794
1795	/*
1796	 * Always set the range to a full range, otherwise we can get into
1797	 * several problems, from missing file extent items to represent holes
1798	 * when not using the NO_HOLES feature, to log tree corruption due to
1799	 * races between hole detection during logging and completion of ordered
1800	 * extents outside the range, to missing checksums due to ordered extents
1801	 * for which we flushed only a subset of their pages.
1802	 */
1803	start = 0;
1804	end = LLONG_MAX;
1805	len = (u64)LLONG_MAX + 1;
1806
1807	/*
1808	 * We write the dirty pages in the range and wait until they complete
1809	 * out of the ->i_mutex. If so, we can flush the dirty pages by
1810	 * multi-task, and make the performance up.  See
1811	 * btrfs_wait_ordered_range for an explanation of the ASYNC check.
1812	 */
1813	ret = start_ordered_ops(inode, start, end);
1814	if (ret)
1815		goto out;
1816
1817	btrfs_inode_lock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
 
 
 
 
 
 
 
1818
1819	atomic_inc(&root->log_batch);
1820
1821	/*
1822	 * Before we acquired the inode's lock and the mmap lock, someone may
1823	 * have dirtied more pages in the target range. We need to make sure
1824	 * that writeback for any such pages does not start while we are logging
1825	 * the inode, because if it does, any of the following might happen when
1826	 * we are not doing a full inode sync:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1827	 *
1828	 * 1) We log an extent after its writeback finishes but before its
1829	 *    checksums are added to the csum tree, leading to -EIO errors
1830	 *    when attempting to read the extent after a log replay.
1831	 *
1832	 * 2) We can end up logging an extent before its writeback finishes.
1833	 *    Therefore after the log replay we will have a file extent item
1834	 *    pointing to an unwritten extent (and no data checksums as well).
1835	 *
1836	 * So trigger writeback for any eventual new dirty pages and then we
1837	 * wait for all ordered extents to complete below.
1838	 */
1839	ret = start_ordered_ops(inode, start, end);
1840	if (ret) {
1841		btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
 
1842		goto out;
1843	}
1844
1845	/*
1846	 * Always check for the full sync flag while holding the inode's lock,
1847	 * to avoid races with other tasks. The flag must be either set all the
1848	 * time during logging or always off all the time while logging.
1849	 * We check the flag here after starting delalloc above, because when
1850	 * running delalloc the full sync flag may be set if we need to drop
1851	 * extra extent map ranges due to temporary memory allocation failures.
1852	 */
1853	full_sync = test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
1854			     &BTRFS_I(inode)->runtime_flags);
1855
1856	/*
1857	 * We have to do this here to avoid the priority inversion of waiting on
1858	 * IO of a lower priority task while holding a transaction open.
1859	 *
1860	 * For a full fsync we wait for the ordered extents to complete while
1861	 * for a fast fsync we wait just for writeback to complete, and then
1862	 * attach the ordered extents to the transaction so that a transaction
1863	 * commit waits for their completion, to avoid data loss if we fsync,
1864	 * the current transaction commits before the ordered extents complete
1865	 * and a power failure happens right after that.
1866	 *
1867	 * For zoned filesystem, if a write IO uses a ZONE_APPEND command, the
1868	 * logical address recorded in the ordered extent may change. We need
1869	 * to wait for the IO to stabilize the logical address.
1870	 */
1871	if (full_sync || btrfs_is_zoned(fs_info)) {
1872		ret = btrfs_wait_ordered_range(inode, start, len);
1873	} else {
1874		/*
1875		 * Get our ordered extents as soon as possible to avoid doing
1876		 * checksum lookups in the csum tree, and use instead the
1877		 * checksums attached to the ordered extents.
1878		 */
1879		btrfs_get_ordered_extents_for_logging(BTRFS_I(inode),
1880						      &ctx.ordered_extents);
1881		ret = filemap_fdatawait_range(inode->i_mapping, start, end);
1882	}
1883
1884	if (ret)
1885		goto out_release_extents;
1886
1887	atomic_inc(&root->log_batch);
1888
1889	smp_mb();
1890	if (skip_inode_logging(&ctx)) {
 
1891		/*
1892		 * We've had everything committed since the last time we were
1893		 * modified so clear this flag in case it was set for whatever
1894		 * reason, it's no longer relevant.
1895		 */
1896		clear_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
1897			  &BTRFS_I(inode)->runtime_flags);
1898		/*
1899		 * An ordered extent might have started before and completed
1900		 * already with io errors, in which case the inode was not
1901		 * updated and we end up here. So check the inode's mapping
1902		 * for any errors that might have happened since we last
1903		 * checked called fsync.
1904		 */
1905		ret = filemap_check_wb_err(inode->i_mapping, file->f_wb_err);
1906		goto out_release_extents;
 
 
1907	}
1908
1909	/*
1910	 * We use start here because we will need to wait on the IO to complete
1911	 * in btrfs_sync_log, which could require joining a transaction (for
1912	 * example checking cross references in the nocow path).  If we use join
1913	 * here we could get into a situation where we're waiting on IO to
1914	 * happen that is blocked on a transaction trying to commit.  With start
1915	 * we inc the extwriter counter, so we wait for all extwriters to exit
1916	 * before we start blocking joiners.  This comment is to keep somebody
1917	 * from thinking they are super smart and changing this to
1918	 * btrfs_join_transaction *cough*Josef*cough*.
1919	 */
1920	trans = btrfs_start_transaction(root, 0);
1921	if (IS_ERR(trans)) {
1922		ret = PTR_ERR(trans);
1923		goto out_release_extents;
 
 
1924	}
1925	trans->in_fsync = true;
1926
1927	ret = btrfs_log_dentry_safe(trans, dentry, &ctx);
1928	btrfs_release_log_ctx_extents(&ctx);
1929	if (ret < 0) {
1930		/* Fallthrough and commit/free transaction. */
1931		ret = BTRFS_LOG_FORCE_COMMIT;
1932	}
1933
1934	/* we've logged all the items and now have a consistent
1935	 * version of the file in the log.  It is possible that
1936	 * someone will come in and modify the file, but that's
1937	 * fine because the log is consistent on disk, and we
1938	 * have references to all of the file's extents
1939	 *
1940	 * It is possible that someone will come in and log the
1941	 * file again, but that will end up using the synchronization
1942	 * inside btrfs_sync_log to keep things safe.
1943	 */
1944	btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
1945
1946	if (ret == BTRFS_NO_LOG_SYNC) {
1947		ret = btrfs_end_transaction(trans);
1948		goto out;
1949	}
1950
1951	/* We successfully logged the inode, attempt to sync the log. */
1952	if (!ret) {
1953		ret = btrfs_sync_log(trans, root, &ctx);
1954		if (!ret) {
1955			ret = btrfs_end_transaction(trans);
1956			goto out;
 
 
 
1957		}
1958	}
1959
1960	/*
1961	 * At this point we need to commit the transaction because we had
1962	 * btrfs_need_log_full_commit() or some other error.
1963	 *
1964	 * If we didn't do a full sync we have to stop the trans handle, wait on
1965	 * the ordered extents, start it again and commit the transaction.  If
1966	 * we attempt to wait on the ordered extents here we could deadlock with
1967	 * something like fallocate() that is holding the extent lock trying to
1968	 * start a transaction while some other thread is trying to commit the
1969	 * transaction while we (fsync) are currently holding the transaction
1970	 * open.
1971	 */
1972	if (!full_sync) {
1973		ret = btrfs_end_transaction(trans);
1974		if (ret)
1975			goto out;
1976		ret = btrfs_wait_ordered_range(inode, start, len);
1977		if (ret)
1978			goto out;
1979
1980		/*
1981		 * This is safe to use here because we're only interested in
1982		 * making sure the transaction that had the ordered extents is
1983		 * committed.  We aren't waiting on anything past this point,
1984		 * we're purely getting the transaction and committing it.
1985		 */
1986		trans = btrfs_attach_transaction_barrier(root);
1987		if (IS_ERR(trans)) {
1988			ret = PTR_ERR(trans);
1989
1990			/*
1991			 * We committed the transaction and there's no currently
1992			 * running transaction, this means everything we care
1993			 * about made it to disk and we are done.
1994			 */
1995			if (ret == -ENOENT)
1996				ret = 0;
1997			goto out;
1998		}
1999	}
2000
2001	ret = btrfs_commit_transaction(trans);
2002out:
2003	ASSERT(list_empty(&ctx.list));
2004	ASSERT(list_empty(&ctx.conflict_inodes));
2005	err = file_check_and_advance_wb_err(file);
2006	if (!ret)
2007		ret = err;
2008	return ret > 0 ? -EIO : ret;
2009
2010out_release_extents:
2011	btrfs_release_log_ctx_extents(&ctx);
2012	btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
2013	goto out;
2014}
2015
2016static const struct vm_operations_struct btrfs_file_vm_ops = {
2017	.fault		= filemap_fault,
2018	.map_pages	= filemap_map_pages,
2019	.page_mkwrite	= btrfs_page_mkwrite,
2020};
2021
2022static int btrfs_file_mmap(struct file	*filp, struct vm_area_struct *vma)
2023{
2024	struct address_space *mapping = filp->f_mapping;
2025
2026	if (!mapping->a_ops->read_folio)
2027		return -ENOEXEC;
2028
2029	file_accessed(filp);
2030	vma->vm_ops = &btrfs_file_vm_ops;
2031
2032	return 0;
2033}
2034
2035static int hole_mergeable(struct btrfs_inode *inode, struct extent_buffer *leaf,
2036			  int slot, u64 start, u64 end)
2037{
2038	struct btrfs_file_extent_item *fi;
2039	struct btrfs_key key;
2040
2041	if (slot < 0 || slot >= btrfs_header_nritems(leaf))
2042		return 0;
2043
2044	btrfs_item_key_to_cpu(leaf, &key, slot);
2045	if (key.objectid != btrfs_ino(inode) ||
2046	    key.type != BTRFS_EXTENT_DATA_KEY)
2047		return 0;
2048
2049	fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
2050
2051	if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2052		return 0;
2053
2054	if (btrfs_file_extent_disk_bytenr(leaf, fi))
2055		return 0;
2056
2057	if (key.offset == end)
2058		return 1;
2059	if (key.offset + btrfs_file_extent_num_bytes(leaf, fi) == start)
2060		return 1;
2061	return 0;
2062}
2063
2064static int fill_holes(struct btrfs_trans_handle *trans,
2065		struct btrfs_inode *inode,
2066		struct btrfs_path *path, u64 offset, u64 end)
2067{
2068	struct btrfs_fs_info *fs_info = trans->fs_info;
2069	struct btrfs_root *root = inode->root;
2070	struct extent_buffer *leaf;
2071	struct btrfs_file_extent_item *fi;
2072	struct extent_map *hole_em;
 
2073	struct btrfs_key key;
2074	int ret;
2075
2076	if (btrfs_fs_incompat(fs_info, NO_HOLES))
2077		goto out;
2078
2079	key.objectid = btrfs_ino(inode);
2080	key.type = BTRFS_EXTENT_DATA_KEY;
2081	key.offset = offset;
2082
2083	ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2084	if (ret <= 0) {
2085		/*
2086		 * We should have dropped this offset, so if we find it then
2087		 * something has gone horribly wrong.
2088		 */
2089		if (ret == 0)
2090			ret = -EINVAL;
2091		return ret;
2092	}
2093
2094	leaf = path->nodes[0];
2095	if (hole_mergeable(inode, leaf, path->slots[0] - 1, offset, end)) {
2096		u64 num_bytes;
2097
2098		path->slots[0]--;
2099		fi = btrfs_item_ptr(leaf, path->slots[0],
2100				    struct btrfs_file_extent_item);
2101		num_bytes = btrfs_file_extent_num_bytes(leaf, fi) +
2102			end - offset;
2103		btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2104		btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
2105		btrfs_set_file_extent_offset(leaf, fi, 0);
2106		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
2107		btrfs_mark_buffer_dirty(leaf);
2108		goto out;
2109	}
2110
2111	if (hole_mergeable(inode, leaf, path->slots[0], offset, end)) {
2112		u64 num_bytes;
2113
2114		key.offset = offset;
2115		btrfs_set_item_key_safe(fs_info, path, &key);
2116		fi = btrfs_item_ptr(leaf, path->slots[0],
2117				    struct btrfs_file_extent_item);
2118		num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + end -
2119			offset;
2120		btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2121		btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
2122		btrfs_set_file_extent_offset(leaf, fi, 0);
2123		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
2124		btrfs_mark_buffer_dirty(leaf);
2125		goto out;
2126	}
2127	btrfs_release_path(path);
2128
2129	ret = btrfs_insert_hole_extent(trans, root, btrfs_ino(inode), offset,
2130				       end - offset);
2131	if (ret)
2132		return ret;
2133
2134out:
2135	btrfs_release_path(path);
2136
2137	hole_em = alloc_extent_map();
2138	if (!hole_em) {
2139		btrfs_drop_extent_map_range(inode, offset, end - 1, false);
2140		btrfs_set_inode_full_sync(inode);
2141	} else {
2142		hole_em->start = offset;
2143		hole_em->len = end - offset;
2144		hole_em->ram_bytes = hole_em->len;
2145		hole_em->orig_start = offset;
2146
2147		hole_em->block_start = EXTENT_MAP_HOLE;
2148		hole_em->block_len = 0;
2149		hole_em->orig_block_len = 0;
2150		hole_em->compress_type = BTRFS_COMPRESS_NONE;
2151		hole_em->generation = trans->transid;
2152
2153		ret = btrfs_replace_extent_map_range(inode, hole_em, true);
 
 
 
 
 
2154		free_extent_map(hole_em);
2155		if (ret)
2156			btrfs_set_inode_full_sync(inode);
 
2157	}
2158
2159	return 0;
2160}
2161
2162/*
2163 * Find a hole extent on given inode and change start/len to the end of hole
2164 * extent.(hole/vacuum extent whose em->start <= start &&
2165 *	   em->start + em->len > start)
2166 * When a hole extent is found, return 1 and modify start/len.
2167 */
2168static int find_first_non_hole(struct btrfs_inode *inode, u64 *start, u64 *len)
2169{
2170	struct btrfs_fs_info *fs_info = inode->root->fs_info;
2171	struct extent_map *em;
2172	int ret = 0;
2173
2174	em = btrfs_get_extent(inode, NULL, 0,
2175			      round_down(*start, fs_info->sectorsize),
2176			      round_up(*len, fs_info->sectorsize));
2177	if (IS_ERR(em))
2178		return PTR_ERR(em);
2179
2180	/* Hole or vacuum extent(only exists in no-hole mode) */
2181	if (em->block_start == EXTENT_MAP_HOLE) {
2182		ret = 1;
2183		*len = em->start + em->len > *start + *len ?
2184		       0 : *start + *len - em->start - em->len;
2185		*start = em->start + em->len;
2186	}
2187	free_extent_map(em);
2188	return ret;
2189}
2190
2191static void btrfs_punch_hole_lock_range(struct inode *inode,
2192					const u64 lockstart,
2193					const u64 lockend,
2194					struct extent_state **cached_state)
2195{
2196	/*
2197	 * For subpage case, if the range is not at page boundary, we could
2198	 * have pages at the leading/tailing part of the range.
2199	 * This could lead to dead loop since filemap_range_has_page()
2200	 * will always return true.
2201	 * So here we need to do extra page alignment for
2202	 * filemap_range_has_page().
2203	 */
2204	const u64 page_lockstart = round_up(lockstart, PAGE_SIZE);
2205	const u64 page_lockend = round_down(lockend + 1, PAGE_SIZE) - 1;
2206
2207	while (1) {
 
 
 
2208		truncate_pagecache_range(inode, lockstart, lockend);
2209
2210		lock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2211			    cached_state);
2212		/*
2213		 * We can't have ordered extents in the range, nor dirty/writeback
2214		 * pages, because we have locked the inode's VFS lock in exclusive
2215		 * mode, we have locked the inode's i_mmap_lock in exclusive mode,
2216		 * we have flushed all delalloc in the range and we have waited
2217		 * for any ordered extents in the range to complete.
2218		 * We can race with anyone reading pages from this range, so after
2219		 * locking the range check if we have pages in the range, and if
2220		 * we do, unlock the range and retry.
2221		 */
2222		if (!filemap_range_has_page(inode->i_mapping, page_lockstart,
2223					    page_lockend))
 
 
2224			break;
2225
2226		unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2227			      cached_state);
 
 
 
 
 
 
2228	}
2229
2230	btrfs_assert_inode_range_clean(BTRFS_I(inode), lockstart, lockend);
2231}
2232
2233static int btrfs_insert_replace_extent(struct btrfs_trans_handle *trans,
2234				     struct btrfs_inode *inode,
2235				     struct btrfs_path *path,
2236				     struct btrfs_replace_extent_info *extent_info,
2237				     const u64 replace_len,
2238				     const u64 bytes_to_drop)
2239{
2240	struct btrfs_fs_info *fs_info = trans->fs_info;
2241	struct btrfs_root *root = inode->root;
2242	struct btrfs_file_extent_item *extent;
2243	struct extent_buffer *leaf;
2244	struct btrfs_key key;
2245	int slot;
2246	struct btrfs_ref ref = { 0 };
 
2247	int ret;
2248
2249	if (replace_len == 0)
2250		return 0;
2251
2252	if (extent_info->disk_offset == 0 &&
2253	    btrfs_fs_incompat(fs_info, NO_HOLES)) {
2254		btrfs_update_inode_bytes(inode, 0, bytes_to_drop);
2255		return 0;
2256	}
2257
2258	key.objectid = btrfs_ino(inode);
2259	key.type = BTRFS_EXTENT_DATA_KEY;
2260	key.offset = extent_info->file_offset;
2261	ret = btrfs_insert_empty_item(trans, root, path, &key,
2262				      sizeof(struct btrfs_file_extent_item));
2263	if (ret)
2264		return ret;
2265	leaf = path->nodes[0];
2266	slot = path->slots[0];
2267	write_extent_buffer(leaf, extent_info->extent_buf,
2268			    btrfs_item_ptr_offset(leaf, slot),
2269			    sizeof(struct btrfs_file_extent_item));
2270	extent = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
2271	ASSERT(btrfs_file_extent_type(leaf, extent) != BTRFS_FILE_EXTENT_INLINE);
2272	btrfs_set_file_extent_offset(leaf, extent, extent_info->data_offset);
2273	btrfs_set_file_extent_num_bytes(leaf, extent, replace_len);
2274	if (extent_info->is_new_extent)
2275		btrfs_set_file_extent_generation(leaf, extent, trans->transid);
2276	btrfs_mark_buffer_dirty(leaf);
2277	btrfs_release_path(path);
2278
2279	ret = btrfs_inode_set_file_extent_range(inode, extent_info->file_offset,
2280						replace_len);
2281	if (ret)
2282		return ret;
2283
2284	/* If it's a hole, nothing more needs to be done. */
2285	if (extent_info->disk_offset == 0) {
2286		btrfs_update_inode_bytes(inode, 0, bytes_to_drop);
2287		return 0;
2288	}
2289
2290	btrfs_update_inode_bytes(inode, replace_len, bytes_to_drop);
2291
2292	if (extent_info->is_new_extent && extent_info->insertions == 0) {
2293		key.objectid = extent_info->disk_offset;
2294		key.type = BTRFS_EXTENT_ITEM_KEY;
2295		key.offset = extent_info->disk_len;
2296		ret = btrfs_alloc_reserved_file_extent(trans, root,
2297						       btrfs_ino(inode),
2298						       extent_info->file_offset,
2299						       extent_info->qgroup_reserved,
2300						       &key);
2301	} else {
2302		u64 ref_offset;
2303
2304		btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
2305				       extent_info->disk_offset,
2306				       extent_info->disk_len, 0);
2307		ref_offset = extent_info->file_offset - extent_info->data_offset;
2308		btrfs_init_data_ref(&ref, root->root_key.objectid,
2309				    btrfs_ino(inode), ref_offset, 0, false);
2310		ret = btrfs_inc_extent_ref(trans, &ref);
2311	}
2312
2313	extent_info->insertions++;
 
 
 
 
 
 
 
2314
2315	return ret;
2316}
2317
2318/*
2319 * The respective range must have been previously locked, as well as the inode.
2320 * The end offset is inclusive (last byte of the range).
2321 * @extent_info is NULL for fallocate's hole punching and non-NULL when replacing
2322 * the file range with an extent.
2323 * When not punching a hole, we don't want to end up in a state where we dropped
2324 * extents without inserting a new one, so we must abort the transaction to avoid
2325 * a corruption.
2326 */
2327int btrfs_replace_file_extents(struct btrfs_inode *inode,
2328			       struct btrfs_path *path, const u64 start,
2329			       const u64 end,
2330			       struct btrfs_replace_extent_info *extent_info,
2331			       struct btrfs_trans_handle **trans_out)
2332{
2333	struct btrfs_drop_extents_args drop_args = { 0 };
2334	struct btrfs_root *root = inode->root;
2335	struct btrfs_fs_info *fs_info = root->fs_info;
2336	u64 min_size = btrfs_calc_insert_metadata_size(fs_info, 1);
2337	u64 ino_size = round_up(inode->vfs_inode.i_size, fs_info->sectorsize);
 
2338	struct btrfs_trans_handle *trans = NULL;
2339	struct btrfs_block_rsv *rsv;
2340	unsigned int rsv_count;
2341	u64 cur_offset;
 
2342	u64 len = end - start;
2343	int ret = 0;
2344
2345	if (end <= start)
2346		return -EINVAL;
2347
2348	rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
2349	if (!rsv) {
2350		ret = -ENOMEM;
2351		goto out;
2352	}
2353	rsv->size = btrfs_calc_insert_metadata_size(fs_info, 1);
2354	rsv->failfast = true;
2355
2356	/*
2357	 * 1 - update the inode
2358	 * 1 - removing the extents in the range
2359	 * 1 - adding the hole extent if no_holes isn't set or if we are
2360	 *     replacing the range with a new extent
2361	 */
2362	if (!btrfs_fs_incompat(fs_info, NO_HOLES) || extent_info)
2363		rsv_count = 3;
2364	else
2365		rsv_count = 2;
2366
2367	trans = btrfs_start_transaction(root, rsv_count);
2368	if (IS_ERR(trans)) {
2369		ret = PTR_ERR(trans);
2370		trans = NULL;
2371		goto out_free;
2372	}
2373
2374	ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv,
2375				      min_size, false);
2376	if (WARN_ON(ret))
2377		goto out_trans;
2378	trans->block_rsv = rsv;
2379
2380	cur_offset = start;
2381	drop_args.path = path;
2382	drop_args.end = end + 1;
2383	drop_args.drop_cache = true;
2384	while (cur_offset < end) {
2385		drop_args.start = cur_offset;
2386		ret = btrfs_drop_extents(trans, root, inode, &drop_args);
2387		/* If we are punching a hole decrement the inode's byte count */
2388		if (!extent_info)
2389			btrfs_update_inode_bytes(inode, 0,
2390						 drop_args.bytes_found);
2391		if (ret != -ENOSPC) {
2392			/*
2393			 * The only time we don't want to abort is if we are
2394			 * attempting to clone a partial inline extent, in which
2395			 * case we'll get EOPNOTSUPP.  However if we aren't
2396			 * clone we need to abort no matter what, because if we
2397			 * got EOPNOTSUPP via prealloc then we messed up and
2398			 * need to abort.
2399			 */
2400			if (ret &&
2401			    (ret != -EOPNOTSUPP ||
2402			     (extent_info && extent_info->is_new_extent)))
2403				btrfs_abort_transaction(trans, ret);
2404			break;
2405		}
2406
2407		trans->block_rsv = &fs_info->trans_block_rsv;
2408
2409		if (!extent_info && cur_offset < drop_args.drop_end &&
2410		    cur_offset < ino_size) {
2411			ret = fill_holes(trans, inode, path, cur_offset,
2412					 drop_args.drop_end);
2413			if (ret) {
2414				/*
2415				 * If we failed then we didn't insert our hole
2416				 * entries for the area we dropped, so now the
2417				 * fs is corrupted, so we must abort the
2418				 * transaction.
2419				 */
2420				btrfs_abort_transaction(trans, ret);
2421				break;
2422			}
2423		} else if (!extent_info && cur_offset < drop_args.drop_end) {
2424			/*
2425			 * We are past the i_size here, but since we didn't
2426			 * insert holes we need to clear the mapped area so we
2427			 * know to not set disk_i_size in this area until a new
2428			 * file extent is inserted here.
2429			 */
2430			ret = btrfs_inode_clear_file_extent_range(inode,
2431					cur_offset,
2432					drop_args.drop_end - cur_offset);
2433			if (ret) {
2434				/*
2435				 * We couldn't clear our area, so we could
2436				 * presumably adjust up and corrupt the fs, so
2437				 * we need to abort.
2438				 */
2439				btrfs_abort_transaction(trans, ret);
2440				break;
2441			}
2442		}
2443
2444		if (extent_info &&
2445		    drop_args.drop_end > extent_info->file_offset) {
2446			u64 replace_len = drop_args.drop_end -
2447					  extent_info->file_offset;
2448
2449			ret = btrfs_insert_replace_extent(trans, inode,	path,
2450					extent_info, replace_len,
2451					drop_args.bytes_found);
2452			if (ret) {
2453				btrfs_abort_transaction(trans, ret);
2454				break;
2455			}
2456			extent_info->data_len -= replace_len;
2457			extent_info->data_offset += replace_len;
2458			extent_info->file_offset += replace_len;
2459		}
2460
2461		/*
2462		 * We are releasing our handle on the transaction, balance the
2463		 * dirty pages of the btree inode and flush delayed items, and
2464		 * then get a new transaction handle, which may now point to a
2465		 * new transaction in case someone else may have committed the
2466		 * transaction we used to replace/drop file extent items. So
2467		 * bump the inode's iversion and update mtime and ctime except
2468		 * if we are called from a dedupe context. This is because a
2469		 * power failure/crash may happen after the transaction is
2470		 * committed and before we finish replacing/dropping all the
2471		 * file extent items we need.
2472		 */
2473		inode_inc_iversion(&inode->vfs_inode);
2474
2475		if (!extent_info || extent_info->update_times) {
2476			inode->vfs_inode.i_mtime = current_time(&inode->vfs_inode);
2477			inode->vfs_inode.i_ctime = inode->vfs_inode.i_mtime;
2478		}
2479
2480		ret = btrfs_update_inode(trans, root, inode);
2481		if (ret)
2482			break;
2483
2484		btrfs_end_transaction(trans);
2485		btrfs_btree_balance_dirty(fs_info);
2486
2487		trans = btrfs_start_transaction(root, rsv_count);
2488		if (IS_ERR(trans)) {
2489			ret = PTR_ERR(trans);
2490			trans = NULL;
2491			break;
2492		}
2493
2494		ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv,
2495					      rsv, min_size, false);
2496		if (WARN_ON(ret))
2497			break;
2498		trans->block_rsv = rsv;
2499
2500		cur_offset = drop_args.drop_end;
2501		len = end - cur_offset;
2502		if (!extent_info && len) {
2503			ret = find_first_non_hole(inode, &cur_offset, &len);
2504			if (unlikely(ret < 0))
2505				break;
2506			if (ret && !len) {
2507				ret = 0;
2508				break;
2509			}
2510		}
2511	}
2512
2513	/*
2514	 * If we were cloning, force the next fsync to be a full one since we
2515	 * we replaced (or just dropped in the case of cloning holes when
2516	 * NO_HOLES is enabled) file extent items and did not setup new extent
2517	 * maps for the replacement extents (or holes).
2518	 */
2519	if (extent_info && !extent_info->is_new_extent)
2520		btrfs_set_inode_full_sync(inode);
 
 
 
2521
2522	if (ret)
2523		goto out_trans;
2524
2525	trans->block_rsv = &fs_info->trans_block_rsv;
2526	/*
2527	 * If we are using the NO_HOLES feature we might have had already an
2528	 * hole that overlaps a part of the region [lockstart, lockend] and
2529	 * ends at (or beyond) lockend. Since we have no file extent items to
2530	 * represent holes, drop_end can be less than lockend and so we must
2531	 * make sure we have an extent map representing the existing hole (the
2532	 * call to __btrfs_drop_extents() might have dropped the existing extent
2533	 * map representing the existing hole), otherwise the fast fsync path
2534	 * will not record the existence of the hole region
2535	 * [existing_hole_start, lockend].
2536	 */
2537	if (drop_args.drop_end <= end)
2538		drop_args.drop_end = end + 1;
2539	/*
2540	 * Don't insert file hole extent item if it's for a range beyond eof
2541	 * (because it's useless) or if it represents a 0 bytes range (when
2542	 * cur_offset == drop_end).
2543	 */
2544	if (!extent_info && cur_offset < ino_size &&
2545	    cur_offset < drop_args.drop_end) {
2546		ret = fill_holes(trans, inode, path, cur_offset,
2547				 drop_args.drop_end);
2548		if (ret) {
2549			/* Same comment as above. */
2550			btrfs_abort_transaction(trans, ret);
2551			goto out_trans;
2552		}
2553	} else if (!extent_info && cur_offset < drop_args.drop_end) {
2554		/* See the comment in the loop above for the reasoning here. */
2555		ret = btrfs_inode_clear_file_extent_range(inode, cur_offset,
2556					drop_args.drop_end - cur_offset);
2557		if (ret) {
2558			btrfs_abort_transaction(trans, ret);
2559			goto out_trans;
2560		}
2561
2562	}
2563	if (extent_info) {
2564		ret = btrfs_insert_replace_extent(trans, inode, path,
2565				extent_info, extent_info->data_len,
2566				drop_args.bytes_found);
2567		if (ret) {
2568			btrfs_abort_transaction(trans, ret);
2569			goto out_trans;
2570		}
2571	}
2572
2573out_trans:
2574	if (!trans)
2575		goto out_free;
2576
2577	trans->block_rsv = &fs_info->trans_block_rsv;
2578	if (ret)
2579		btrfs_end_transaction(trans);
2580	else
2581		*trans_out = trans;
2582out_free:
2583	btrfs_free_block_rsv(fs_info, rsv);
2584out:
2585	return ret;
2586}
2587
2588static int btrfs_punch_hole(struct file *file, loff_t offset, loff_t len)
2589{
2590	struct inode *inode = file_inode(file);
2591	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2592	struct btrfs_root *root = BTRFS_I(inode)->root;
2593	struct extent_state *cached_state = NULL;
2594	struct btrfs_path *path;
2595	struct btrfs_trans_handle *trans = NULL;
2596	u64 lockstart;
2597	u64 lockend;
2598	u64 tail_start;
2599	u64 tail_len;
2600	u64 orig_start = offset;
2601	int ret = 0;
2602	bool same_block;
2603	u64 ino_size;
2604	bool truncated_block = false;
2605	bool updated_inode = false;
2606
2607	btrfs_inode_lock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
2608
2609	ret = btrfs_wait_ordered_range(inode, offset, len);
2610	if (ret)
2611		goto out_only_mutex;
2612
 
2613	ino_size = round_up(inode->i_size, fs_info->sectorsize);
2614	ret = find_first_non_hole(BTRFS_I(inode), &offset, &len);
2615	if (ret < 0)
2616		goto out_only_mutex;
2617	if (ret && !len) {
2618		/* Already in a large hole */
2619		ret = 0;
2620		goto out_only_mutex;
2621	}
2622
2623	ret = file_modified(file);
2624	if (ret)
2625		goto out_only_mutex;
2626
2627	lockstart = round_up(offset, fs_info->sectorsize);
2628	lockend = round_down(offset + len, fs_info->sectorsize) - 1;
2629	same_block = (BTRFS_BYTES_TO_BLKS(fs_info, offset))
2630		== (BTRFS_BYTES_TO_BLKS(fs_info, offset + len - 1));
2631	/*
2632	 * We needn't truncate any block which is beyond the end of the file
2633	 * because we are sure there is no data there.
2634	 */
2635	/*
2636	 * Only do this if we are in the same block and we aren't doing the
2637	 * entire block.
2638	 */
2639	if (same_block && len < fs_info->sectorsize) {
2640		if (offset < ino_size) {
2641			truncated_block = true;
2642			ret = btrfs_truncate_block(BTRFS_I(inode), offset, len,
2643						   0);
2644		} else {
2645			ret = 0;
2646		}
2647		goto out_only_mutex;
2648	}
2649
2650	/* zero back part of the first block */
2651	if (offset < ino_size) {
2652		truncated_block = true;
2653		ret = btrfs_truncate_block(BTRFS_I(inode), offset, 0, 0);
2654		if (ret) {
2655			btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
2656			return ret;
2657		}
2658	}
2659
2660	/* Check the aligned pages after the first unaligned page,
2661	 * if offset != orig_start, which means the first unaligned page
2662	 * including several following pages are already in holes,
2663	 * the extra check can be skipped */
2664	if (offset == orig_start) {
2665		/* after truncate page, check hole again */
2666		len = offset + len - lockstart;
2667		offset = lockstart;
2668		ret = find_first_non_hole(BTRFS_I(inode), &offset, &len);
2669		if (ret < 0)
2670			goto out_only_mutex;
2671		if (ret && !len) {
2672			ret = 0;
2673			goto out_only_mutex;
2674		}
2675		lockstart = offset;
2676	}
2677
2678	/* Check the tail unaligned part is in a hole */
2679	tail_start = lockend + 1;
2680	tail_len = offset + len - tail_start;
2681	if (tail_len) {
2682		ret = find_first_non_hole(BTRFS_I(inode), &tail_start, &tail_len);
2683		if (unlikely(ret < 0))
2684			goto out_only_mutex;
2685		if (!ret) {
2686			/* zero the front end of the last page */
2687			if (tail_start + tail_len < ino_size) {
2688				truncated_block = true;
2689				ret = btrfs_truncate_block(BTRFS_I(inode),
2690							tail_start + tail_len,
2691							0, 1);
2692				if (ret)
2693					goto out_only_mutex;
2694			}
2695		}
2696	}
2697
2698	if (lockend < lockstart) {
2699		ret = 0;
2700		goto out_only_mutex;
2701	}
2702
2703	btrfs_punch_hole_lock_range(inode, lockstart, lockend, &cached_state);
 
 
 
2704
2705	path = btrfs_alloc_path();
2706	if (!path) {
2707		ret = -ENOMEM;
2708		goto out;
2709	}
2710
2711	ret = btrfs_replace_file_extents(BTRFS_I(inode), path, lockstart,
2712					 lockend, NULL, &trans);
2713	btrfs_free_path(path);
2714	if (ret)
2715		goto out;
2716
2717	ASSERT(trans != NULL);
2718	inode_inc_iversion(inode);
2719	inode->i_mtime = current_time(inode);
2720	inode->i_ctime = inode->i_mtime;
2721	ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
2722	updated_inode = true;
2723	btrfs_end_transaction(trans);
2724	btrfs_btree_balance_dirty(fs_info);
2725out:
2726	unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2727		      &cached_state);
2728out_only_mutex:
2729	if (!updated_inode && truncated_block && !ret) {
2730		/*
2731		 * If we only end up zeroing part of a page, we still need to
2732		 * update the inode item, so that all the time fields are
2733		 * updated as well as the necessary btrfs inode in memory fields
2734		 * for detecting, at fsync time, if the inode isn't yet in the
2735		 * log tree or it's there but not up to date.
2736		 */
2737		struct timespec64 now = current_time(inode);
2738
2739		inode_inc_iversion(inode);
2740		inode->i_mtime = now;
2741		inode->i_ctime = now;
2742		trans = btrfs_start_transaction(root, 1);
2743		if (IS_ERR(trans)) {
2744			ret = PTR_ERR(trans);
2745		} else {
2746			int ret2;
2747
2748			ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
2749			ret2 = btrfs_end_transaction(trans);
2750			if (!ret)
2751				ret = ret2;
2752		}
2753	}
2754	btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
2755	return ret;
2756}
2757
2758/* Helper structure to record which range is already reserved */
2759struct falloc_range {
2760	struct list_head list;
2761	u64 start;
2762	u64 len;
2763};
2764
2765/*
2766 * Helper function to add falloc range
2767 *
2768 * Caller should have locked the larger range of extent containing
2769 * [start, len)
2770 */
2771static int add_falloc_range(struct list_head *head, u64 start, u64 len)
2772{
 
2773	struct falloc_range *range = NULL;
2774
2775	if (!list_empty(head)) {
2776		/*
2777		 * As fallocate iterates by bytenr order, we only need to check
2778		 * the last range.
2779		 */
2780		range = list_last_entry(head, struct falloc_range, list);
2781		if (range->start + range->len == start) {
2782			range->len += len;
2783			return 0;
2784		}
2785	}
2786
 
 
 
 
 
 
 
 
 
 
2787	range = kmalloc(sizeof(*range), GFP_KERNEL);
2788	if (!range)
2789		return -ENOMEM;
2790	range->start = start;
2791	range->len = len;
2792	list_add_tail(&range->list, head);
2793	return 0;
2794}
2795
2796static int btrfs_fallocate_update_isize(struct inode *inode,
2797					const u64 end,
2798					const int mode)
2799{
2800	struct btrfs_trans_handle *trans;
2801	struct btrfs_root *root = BTRFS_I(inode)->root;
2802	int ret;
2803	int ret2;
2804
2805	if (mode & FALLOC_FL_KEEP_SIZE || end <= i_size_read(inode))
2806		return 0;
2807
2808	trans = btrfs_start_transaction(root, 1);
2809	if (IS_ERR(trans))
2810		return PTR_ERR(trans);
2811
2812	inode->i_ctime = current_time(inode);
2813	i_size_write(inode, end);
2814	btrfs_inode_safe_disk_i_size_write(BTRFS_I(inode), 0);
2815	ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
2816	ret2 = btrfs_end_transaction(trans);
2817
2818	return ret ? ret : ret2;
2819}
2820
2821enum {
2822	RANGE_BOUNDARY_WRITTEN_EXTENT,
2823	RANGE_BOUNDARY_PREALLOC_EXTENT,
2824	RANGE_BOUNDARY_HOLE,
2825};
2826
2827static int btrfs_zero_range_check_range_boundary(struct btrfs_inode *inode,
2828						 u64 offset)
2829{
2830	const u64 sectorsize = inode->root->fs_info->sectorsize;
2831	struct extent_map *em;
2832	int ret;
2833
2834	offset = round_down(offset, sectorsize);
2835	em = btrfs_get_extent(inode, NULL, 0, offset, sectorsize);
2836	if (IS_ERR(em))
2837		return PTR_ERR(em);
2838
2839	if (em->block_start == EXTENT_MAP_HOLE)
2840		ret = RANGE_BOUNDARY_HOLE;
2841	else if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
2842		ret = RANGE_BOUNDARY_PREALLOC_EXTENT;
2843	else
2844		ret = RANGE_BOUNDARY_WRITTEN_EXTENT;
2845
2846	free_extent_map(em);
2847	return ret;
2848}
2849
2850static int btrfs_zero_range(struct inode *inode,
2851			    loff_t offset,
2852			    loff_t len,
2853			    const int mode)
2854{
2855	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2856	struct extent_map *em;
2857	struct extent_changeset *data_reserved = NULL;
2858	int ret;
2859	u64 alloc_hint = 0;
2860	const u64 sectorsize = fs_info->sectorsize;
2861	u64 alloc_start = round_down(offset, sectorsize);
2862	u64 alloc_end = round_up(offset + len, sectorsize);
2863	u64 bytes_to_reserve = 0;
2864	bool space_reserved = false;
2865
 
 
2866	em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, alloc_start,
2867			      alloc_end - alloc_start);
2868	if (IS_ERR(em)) {
2869		ret = PTR_ERR(em);
2870		goto out;
2871	}
2872
2873	/*
2874	 * Avoid hole punching and extent allocation for some cases. More cases
2875	 * could be considered, but these are unlikely common and we keep things
2876	 * as simple as possible for now. Also, intentionally, if the target
2877	 * range contains one or more prealloc extents together with regular
2878	 * extents and holes, we drop all the existing extents and allocate a
2879	 * new prealloc extent, so that we get a larger contiguous disk extent.
2880	 */
2881	if (em->start <= alloc_start &&
2882	    test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
2883		const u64 em_end = em->start + em->len;
2884
2885		if (em_end >= offset + len) {
2886			/*
2887			 * The whole range is already a prealloc extent,
2888			 * do nothing except updating the inode's i_size if
2889			 * needed.
2890			 */
2891			free_extent_map(em);
2892			ret = btrfs_fallocate_update_isize(inode, offset + len,
2893							   mode);
2894			goto out;
2895		}
2896		/*
2897		 * Part of the range is already a prealloc extent, so operate
2898		 * only on the remaining part of the range.
2899		 */
2900		alloc_start = em_end;
2901		ASSERT(IS_ALIGNED(alloc_start, sectorsize));
2902		len = offset + len - alloc_start;
2903		offset = alloc_start;
2904		alloc_hint = em->block_start + em->len;
2905	}
2906	free_extent_map(em);
2907
2908	if (BTRFS_BYTES_TO_BLKS(fs_info, offset) ==
2909	    BTRFS_BYTES_TO_BLKS(fs_info, offset + len - 1)) {
2910		em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, alloc_start,
2911				      sectorsize);
2912		if (IS_ERR(em)) {
2913			ret = PTR_ERR(em);
2914			goto out;
2915		}
2916
2917		if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
2918			free_extent_map(em);
2919			ret = btrfs_fallocate_update_isize(inode, offset + len,
2920							   mode);
2921			goto out;
2922		}
2923		if (len < sectorsize && em->block_start != EXTENT_MAP_HOLE) {
2924			free_extent_map(em);
2925			ret = btrfs_truncate_block(BTRFS_I(inode), offset, len,
2926						   0);
2927			if (!ret)
2928				ret = btrfs_fallocate_update_isize(inode,
2929								   offset + len,
2930								   mode);
2931			return ret;
2932		}
2933		free_extent_map(em);
2934		alloc_start = round_down(offset, sectorsize);
2935		alloc_end = alloc_start + sectorsize;
2936		goto reserve_space;
2937	}
2938
2939	alloc_start = round_up(offset, sectorsize);
2940	alloc_end = round_down(offset + len, sectorsize);
2941
2942	/*
2943	 * For unaligned ranges, check the pages at the boundaries, they might
2944	 * map to an extent, in which case we need to partially zero them, or
2945	 * they might map to a hole, in which case we need our allocation range
2946	 * to cover them.
2947	 */
2948	if (!IS_ALIGNED(offset, sectorsize)) {
2949		ret = btrfs_zero_range_check_range_boundary(BTRFS_I(inode),
2950							    offset);
2951		if (ret < 0)
2952			goto out;
2953		if (ret == RANGE_BOUNDARY_HOLE) {
2954			alloc_start = round_down(offset, sectorsize);
2955			ret = 0;
2956		} else if (ret == RANGE_BOUNDARY_WRITTEN_EXTENT) {
2957			ret = btrfs_truncate_block(BTRFS_I(inode), offset, 0, 0);
2958			if (ret)
2959				goto out;
2960		} else {
2961			ret = 0;
2962		}
2963	}
2964
2965	if (!IS_ALIGNED(offset + len, sectorsize)) {
2966		ret = btrfs_zero_range_check_range_boundary(BTRFS_I(inode),
2967							    offset + len);
2968		if (ret < 0)
2969			goto out;
2970		if (ret == RANGE_BOUNDARY_HOLE) {
2971			alloc_end = round_up(offset + len, sectorsize);
2972			ret = 0;
2973		} else if (ret == RANGE_BOUNDARY_WRITTEN_EXTENT) {
2974			ret = btrfs_truncate_block(BTRFS_I(inode), offset + len,
2975						   0, 1);
2976			if (ret)
2977				goto out;
2978		} else {
2979			ret = 0;
2980		}
2981	}
2982
2983reserve_space:
2984	if (alloc_start < alloc_end) {
2985		struct extent_state *cached_state = NULL;
2986		const u64 lockstart = alloc_start;
2987		const u64 lockend = alloc_end - 1;
2988
2989		bytes_to_reserve = alloc_end - alloc_start;
2990		ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode),
2991						      bytes_to_reserve);
2992		if (ret < 0)
2993			goto out;
2994		space_reserved = true;
2995		btrfs_punch_hole_lock_range(inode, lockstart, lockend,
2996					    &cached_state);
 
 
2997		ret = btrfs_qgroup_reserve_data(BTRFS_I(inode), &data_reserved,
2998						alloc_start, bytes_to_reserve);
2999		if (ret) {
3000			unlock_extent(&BTRFS_I(inode)->io_tree, lockstart,
3001				      lockend, &cached_state);
3002			goto out;
3003		}
3004		ret = btrfs_prealloc_file_range(inode, mode, alloc_start,
3005						alloc_end - alloc_start,
3006						i_blocksize(inode),
3007						offset + len, &alloc_hint);
3008		unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend,
3009			      &cached_state);
3010		/* btrfs_prealloc_file_range releases reserved space on error */
3011		if (ret) {
3012			space_reserved = false;
3013			goto out;
3014		}
3015	}
3016	ret = btrfs_fallocate_update_isize(inode, offset + len, mode);
3017 out:
3018	if (ret && space_reserved)
3019		btrfs_free_reserved_data_space(BTRFS_I(inode), data_reserved,
3020					       alloc_start, bytes_to_reserve);
3021	extent_changeset_free(data_reserved);
3022
3023	return ret;
3024}
3025
3026static long btrfs_fallocate(struct file *file, int mode,
3027			    loff_t offset, loff_t len)
3028{
3029	struct inode *inode = file_inode(file);
3030	struct extent_state *cached_state = NULL;
3031	struct extent_changeset *data_reserved = NULL;
3032	struct falloc_range *range;
3033	struct falloc_range *tmp;
3034	struct list_head reserve_list;
3035	u64 cur_offset;
3036	u64 last_byte;
3037	u64 alloc_start;
3038	u64 alloc_end;
3039	u64 alloc_hint = 0;
3040	u64 locked_end;
3041	u64 actual_end = 0;
3042	u64 data_space_needed = 0;
3043	u64 data_space_reserved = 0;
3044	u64 qgroup_reserved = 0;
3045	struct extent_map *em;
3046	int blocksize = BTRFS_I(inode)->root->fs_info->sectorsize;
3047	int ret;
3048
3049	/* Do not allow fallocate in ZONED mode */
3050	if (btrfs_is_zoned(btrfs_sb(inode->i_sb)))
3051		return -EOPNOTSUPP;
3052
3053	alloc_start = round_down(offset, blocksize);
3054	alloc_end = round_up(offset + len, blocksize);
3055	cur_offset = alloc_start;
3056
3057	/* Make sure we aren't being give some crap mode */
3058	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
3059		     FALLOC_FL_ZERO_RANGE))
3060		return -EOPNOTSUPP;
3061
3062	if (mode & FALLOC_FL_PUNCH_HOLE)
3063		return btrfs_punch_hole(file, offset, len);
 
 
 
 
 
 
 
 
 
 
 
 
3064
3065	btrfs_inode_lock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
3066
3067	if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size) {
3068		ret = inode_newsize_ok(inode, offset + len);
3069		if (ret)
3070			goto out;
3071	}
3072
3073	ret = file_modified(file);
3074	if (ret)
3075		goto out;
3076
3077	/*
3078	 * TODO: Move these two operations after we have checked
3079	 * accurate reserved space, or fallocate can still fail but
3080	 * with page truncated or size expanded.
3081	 *
3082	 * But that's a minor problem and won't do much harm BTW.
3083	 */
3084	if (alloc_start > inode->i_size) {
3085		ret = btrfs_cont_expand(BTRFS_I(inode), i_size_read(inode),
3086					alloc_start);
3087		if (ret)
3088			goto out;
3089	} else if (offset + len > inode->i_size) {
3090		/*
3091		 * If we are fallocating from the end of the file onward we
3092		 * need to zero out the end of the block if i_size lands in the
3093		 * middle of a block.
3094		 */
3095		ret = btrfs_truncate_block(BTRFS_I(inode), inode->i_size, 0, 0);
3096		if (ret)
3097			goto out;
3098	}
3099
3100	/*
3101	 * We have locked the inode at the VFS level (in exclusive mode) and we
3102	 * have locked the i_mmap_lock lock (in exclusive mode). Now before
3103	 * locking the file range, flush all dealloc in the range and wait for
3104	 * all ordered extents in the range to complete. After this we can lock
3105	 * the file range and, due to the previous locking we did, we know there
3106	 * can't be more delalloc or ordered extents in the range.
3107	 */
3108	ret = btrfs_wait_ordered_range(inode, alloc_start,
3109				       alloc_end - alloc_start);
3110	if (ret)
3111		goto out;
3112
3113	if (mode & FALLOC_FL_ZERO_RANGE) {
3114		ret = btrfs_zero_range(inode, offset, len, mode);
3115		btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
3116		return ret;
3117	}
3118
3119	locked_end = alloc_end - 1;
3120	lock_extent(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
3121		    &cached_state);
 
 
 
 
 
 
 
3122
3123	btrfs_assert_inode_range_clean(BTRFS_I(inode), alloc_start, locked_end);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3124
3125	/* First, check if we exceed the qgroup limit */
3126	INIT_LIST_HEAD(&reserve_list);
3127	while (cur_offset < alloc_end) {
3128		em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, cur_offset,
3129				      alloc_end - cur_offset);
3130		if (IS_ERR(em)) {
3131			ret = PTR_ERR(em);
3132			break;
3133		}
3134		last_byte = min(extent_map_end(em), alloc_end);
3135		actual_end = min_t(u64, extent_map_end(em), offset + len);
3136		last_byte = ALIGN(last_byte, blocksize);
3137		if (em->block_start == EXTENT_MAP_HOLE ||
3138		    (cur_offset >= inode->i_size &&
3139		     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
3140			const u64 range_len = last_byte - cur_offset;
3141
3142			ret = add_falloc_range(&reserve_list, cur_offset, range_len);
3143			if (ret < 0) {
3144				free_extent_map(em);
3145				break;
3146			}
3147			ret = btrfs_qgroup_reserve_data(BTRFS_I(inode),
3148					&data_reserved, cur_offset, range_len);
 
3149			if (ret < 0) {
 
3150				free_extent_map(em);
3151				break;
3152			}
3153			qgroup_reserved += range_len;
3154			data_space_needed += range_len;
 
 
 
 
 
 
 
3155		}
3156		free_extent_map(em);
3157		cur_offset = last_byte;
3158	}
3159
3160	if (!ret && data_space_needed > 0) {
3161		/*
3162		 * We are safe to reserve space here as we can't have delalloc
3163		 * in the range, see above.
3164		 */
3165		ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode),
3166						      data_space_needed);
3167		if (!ret)
3168			data_space_reserved = data_space_needed;
3169	}
3170
3171	/*
3172	 * If ret is still 0, means we're OK to fallocate.
3173	 * Or just cleanup the list and exit.
3174	 */
3175	list_for_each_entry_safe(range, tmp, &reserve_list, list) {
3176		if (!ret) {
3177			ret = btrfs_prealloc_file_range(inode, mode,
3178					range->start,
3179					range->len, i_blocksize(inode),
3180					offset + len, &alloc_hint);
3181			/*
3182			 * btrfs_prealloc_file_range() releases space even
3183			 * if it returns an error.
3184			 */
3185			data_space_reserved -= range->len;
3186			qgroup_reserved -= range->len;
3187		} else if (data_space_reserved > 0) {
3188			btrfs_free_reserved_data_space(BTRFS_I(inode),
3189					       data_reserved, range->start,
3190					       range->len);
3191			data_space_reserved -= range->len;
3192			qgroup_reserved -= range->len;
3193		} else if (qgroup_reserved > 0) {
3194			btrfs_qgroup_free_data(BTRFS_I(inode), data_reserved,
3195					       range->start, range->len);
3196			qgroup_reserved -= range->len;
3197		}
3198		list_del(&range->list);
3199		kfree(range);
3200	}
3201	if (ret < 0)
3202		goto out_unlock;
3203
3204	/*
3205	 * We didn't need to allocate any more space, but we still extended the
3206	 * size of the file so we need to update i_size and the inode item.
3207	 */
3208	ret = btrfs_fallocate_update_isize(inode, actual_end, mode);
3209out_unlock:
3210	unlock_extent(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
3211		      &cached_state);
3212out:
3213	btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
 
 
 
 
3214	extent_changeset_free(data_reserved);
3215	return ret;
3216}
3217
3218/*
3219 * Helper for btrfs_find_delalloc_in_range(). Find a subrange in a given range
3220 * that has unflushed and/or flushing delalloc. There might be other adjacent
3221 * subranges after the one it found, so btrfs_find_delalloc_in_range() keeps
3222 * looping while it gets adjacent subranges, and merging them together.
3223 */
3224static bool find_delalloc_subrange(struct btrfs_inode *inode, u64 start, u64 end,
3225				   struct extent_state **cached_state,
3226				   bool *search_io_tree,
3227				   u64 *delalloc_start_ret, u64 *delalloc_end_ret)
3228{
3229	u64 len = end + 1 - start;
3230	u64 delalloc_len = 0;
3231	struct btrfs_ordered_extent *oe;
3232	u64 oe_start;
3233	u64 oe_end;
3234
3235	/*
3236	 * Search the io tree first for EXTENT_DELALLOC. If we find any, it
3237	 * means we have delalloc (dirty pages) for which writeback has not
3238	 * started yet.
3239	 */
3240	if (*search_io_tree) {
3241		spin_lock(&inode->lock);
3242		if (inode->delalloc_bytes > 0) {
3243			spin_unlock(&inode->lock);
3244			*delalloc_start_ret = start;
3245			delalloc_len = count_range_bits(&inode->io_tree,
3246							delalloc_start_ret, end,
3247							len, EXTENT_DELALLOC, 1,
3248							cached_state);
3249		} else {
3250			spin_unlock(&inode->lock);
3251		}
3252	}
3253
3254	if (delalloc_len > 0) {
3255		/*
3256		 * If delalloc was found then *delalloc_start_ret has a sector size
3257		 * aligned value (rounded down).
3258		 */
3259		*delalloc_end_ret = *delalloc_start_ret + delalloc_len - 1;
3260
3261		if (*delalloc_start_ret == start) {
3262			/* Delalloc for the whole range, nothing more to do. */
3263			if (*delalloc_end_ret == end)
3264				return true;
3265			/* Else trim our search range for ordered extents. */
3266			start = *delalloc_end_ret + 1;
3267			len = end + 1 - start;
3268		}
3269	} else {
3270		/* No delalloc, future calls don't need to search again. */
3271		*search_io_tree = false;
3272	}
3273
3274	/*
3275	 * Now also check if there's any ordered extent in the range.
3276	 * We do this because:
3277	 *
3278	 * 1) When delalloc is flushed, the file range is locked, we clear the
3279	 *    EXTENT_DELALLOC bit from the io tree and create an extent map and
3280	 *    an ordered extent for the write. So we might just have been called
3281	 *    after delalloc is flushed and before the ordered extent completes
3282	 *    and inserts the new file extent item in the subvolume's btree;
3283	 *
3284	 * 2) We may have an ordered extent created by flushing delalloc for a
3285	 *    subrange that starts before the subrange we found marked with
3286	 *    EXTENT_DELALLOC in the io tree.
3287	 *
3288	 * We could also use the extent map tree to find such delalloc that is
3289	 * being flushed, but using the ordered extents tree is more efficient
3290	 * because it's usually much smaller as ordered extents are removed from
3291	 * the tree once they complete. With the extent maps, we mau have them
3292	 * in the extent map tree for a very long time, and they were either
3293	 * created by previous writes or loaded by read operations.
3294	 */
3295	oe = btrfs_lookup_first_ordered_range(inode, start, len);
3296	if (!oe)
3297		return (delalloc_len > 0);
3298
3299	/* The ordered extent may span beyond our search range. */
3300	oe_start = max(oe->file_offset, start);
3301	oe_end = min(oe->file_offset + oe->num_bytes - 1, end);
3302
3303	btrfs_put_ordered_extent(oe);
3304
3305	/* Don't have unflushed delalloc, return the ordered extent range. */
3306	if (delalloc_len == 0) {
3307		*delalloc_start_ret = oe_start;
3308		*delalloc_end_ret = oe_end;
3309		return true;
3310	}
3311
3312	/*
3313	 * We have both unflushed delalloc (io_tree) and an ordered extent.
3314	 * If the ranges are adjacent returned a combined range, otherwise
3315	 * return the leftmost range.
3316	 */
3317	if (oe_start < *delalloc_start_ret) {
3318		if (oe_end < *delalloc_start_ret)
3319			*delalloc_end_ret = oe_end;
3320		*delalloc_start_ret = oe_start;
3321	} else if (*delalloc_end_ret + 1 == oe_start) {
3322		*delalloc_end_ret = oe_end;
3323	}
3324
3325	return true;
3326}
3327
3328/*
3329 * Check if there's delalloc in a given range.
3330 *
3331 * @inode:               The inode.
3332 * @start:               The start offset of the range. It does not need to be
3333 *                       sector size aligned.
3334 * @end:                 The end offset (inclusive value) of the search range.
3335 *                       It does not need to be sector size aligned.
3336 * @cached_state:        Extent state record used for speeding up delalloc
3337 *                       searches in the inode's io_tree. Can be NULL.
3338 * @delalloc_start_ret:  Output argument, set to the start offset of the
3339 *                       subrange found with delalloc (may not be sector size
3340 *                       aligned).
3341 * @delalloc_end_ret:    Output argument, set to he end offset (inclusive value)
3342 *                       of the subrange found with delalloc.
3343 *
3344 * Returns true if a subrange with delalloc is found within the given range, and
3345 * if so it sets @delalloc_start_ret and @delalloc_end_ret with the start and
3346 * end offsets of the subrange.
3347 */
3348bool btrfs_find_delalloc_in_range(struct btrfs_inode *inode, u64 start, u64 end,
3349				  struct extent_state **cached_state,
3350				  u64 *delalloc_start_ret, u64 *delalloc_end_ret)
3351{
3352	u64 cur_offset = round_down(start, inode->root->fs_info->sectorsize);
3353	u64 prev_delalloc_end = 0;
3354	bool search_io_tree = true;
3355	bool ret = false;
3356
3357	while (cur_offset <= end) {
3358		u64 delalloc_start;
3359		u64 delalloc_end;
3360		bool delalloc;
3361
3362		delalloc = find_delalloc_subrange(inode, cur_offset, end,
3363						  cached_state, &search_io_tree,
3364						  &delalloc_start,
3365						  &delalloc_end);
3366		if (!delalloc)
3367			break;
3368
3369		if (prev_delalloc_end == 0) {
3370			/* First subrange found. */
3371			*delalloc_start_ret = max(delalloc_start, start);
3372			*delalloc_end_ret = delalloc_end;
3373			ret = true;
3374		} else if (delalloc_start == prev_delalloc_end + 1) {
3375			/* Subrange adjacent to the previous one, merge them. */
3376			*delalloc_end_ret = delalloc_end;
3377		} else {
3378			/* Subrange not adjacent to the previous one, exit. */
3379			break;
3380		}
3381
3382		prev_delalloc_end = delalloc_end;
3383		cur_offset = delalloc_end + 1;
3384		cond_resched();
3385	}
3386
3387	return ret;
3388}
3389
3390/*
3391 * Check if there's a hole or delalloc range in a range representing a hole (or
3392 * prealloc extent) found in the inode's subvolume btree.
3393 *
3394 * @inode:      The inode.
3395 * @whence:     Seek mode (SEEK_DATA or SEEK_HOLE).
3396 * @start:      Start offset of the hole region. It does not need to be sector
3397 *              size aligned.
3398 * @end:        End offset (inclusive value) of the hole region. It does not
3399 *              need to be sector size aligned.
3400 * @start_ret:  Return parameter, used to set the start of the subrange in the
3401 *              hole that matches the search criteria (seek mode), if such
3402 *              subrange is found (return value of the function is true).
3403 *              The value returned here may not be sector size aligned.
3404 *
3405 * Returns true if a subrange matching the given seek mode is found, and if one
3406 * is found, it updates @start_ret with the start of the subrange.
3407 */
3408static bool find_desired_extent_in_hole(struct btrfs_inode *inode, int whence,
3409					struct extent_state **cached_state,
3410					u64 start, u64 end, u64 *start_ret)
3411{
3412	u64 delalloc_start;
3413	u64 delalloc_end;
3414	bool delalloc;
3415
3416	delalloc = btrfs_find_delalloc_in_range(inode, start, end, cached_state,
3417						&delalloc_start, &delalloc_end);
3418	if (delalloc && whence == SEEK_DATA) {
3419		*start_ret = delalloc_start;
3420		return true;
3421	}
3422
3423	if (delalloc && whence == SEEK_HOLE) {
3424		/*
3425		 * We found delalloc but it starts after out start offset. So we
3426		 * have a hole between our start offset and the delalloc start.
3427		 */
3428		if (start < delalloc_start) {
3429			*start_ret = start;
3430			return true;
3431		}
3432		/*
3433		 * Delalloc range starts at our start offset.
3434		 * If the delalloc range's length is smaller than our range,
3435		 * then it means we have a hole that starts where the delalloc
3436		 * subrange ends.
3437		 */
3438		if (delalloc_end < end) {
3439			*start_ret = delalloc_end + 1;
3440			return true;
3441		}
3442
3443		/* There's delalloc for the whole range. */
3444		return false;
3445	}
3446
3447	if (!delalloc && whence == SEEK_HOLE) {
3448		*start_ret = start;
3449		return true;
3450	}
3451
3452	/*
3453	 * No delalloc in the range and we are seeking for data. The caller has
3454	 * to iterate to the next extent item in the subvolume btree.
3455	 */
3456	return false;
3457}
3458
3459static loff_t find_desired_extent(struct file *file, loff_t offset, int whence)
3460{
3461	struct btrfs_inode *inode = BTRFS_I(file->f_mapping->host);
3462	struct btrfs_file_private *private = file->private_data;
3463	struct btrfs_fs_info *fs_info = inode->root->fs_info;
3464	struct extent_state *cached_state = NULL;
3465	struct extent_state **delalloc_cached_state;
3466	const loff_t i_size = i_size_read(&inode->vfs_inode);
3467	const u64 ino = btrfs_ino(inode);
3468	struct btrfs_root *root = inode->root;
3469	struct btrfs_path *path;
3470	struct btrfs_key key;
3471	u64 last_extent_end;
3472	u64 lockstart;
3473	u64 lockend;
3474	u64 start;
3475	int ret;
3476	bool found = false;
3477
3478	if (i_size == 0 || offset >= i_size)
3479		return -ENXIO;
3480
3481	/*
3482	 * Quick path. If the inode has no prealloc extents and its number of
3483	 * bytes used matches its i_size, then it can not have holes.
3484	 */
3485	if (whence == SEEK_HOLE &&
3486	    !(inode->flags & BTRFS_INODE_PREALLOC) &&
3487	    inode_get_bytes(&inode->vfs_inode) == i_size)
3488		return i_size;
3489
3490	if (!private) {
3491		private = kzalloc(sizeof(*private), GFP_KERNEL);
3492		/*
3493		 * No worries if memory allocation failed.
3494		 * The private structure is used only for speeding up multiple
3495		 * lseek SEEK_HOLE/DATA calls to a file when there's delalloc,
3496		 * so everything will still be correct.
3497		 */
3498		file->private_data = private;
3499	}
3500
3501	if (private)
3502		delalloc_cached_state = &private->llseek_cached_state;
3503	else
3504		delalloc_cached_state = NULL;
3505
3506	/*
3507	 * offset can be negative, in this case we start finding DATA/HOLE from
3508	 * the very start of the file.
3509	 */
3510	start = max_t(loff_t, 0, offset);
3511
3512	lockstart = round_down(start, fs_info->sectorsize);
3513	lockend = round_up(i_size, fs_info->sectorsize);
3514	if (lockend <= lockstart)
3515		lockend = lockstart + fs_info->sectorsize;
3516	lockend--;
 
3517
3518	path = btrfs_alloc_path();
3519	if (!path)
3520		return -ENOMEM;
3521	path->reada = READA_FORWARD;
3522
3523	key.objectid = ino;
3524	key.type = BTRFS_EXTENT_DATA_KEY;
3525	key.offset = start;
3526
3527	last_extent_end = lockstart;
3528
3529	lock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
3530
3531	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3532	if (ret < 0) {
3533		goto out;
3534	} else if (ret > 0 && path->slots[0] > 0) {
3535		btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0] - 1);
3536		if (key.objectid == ino && key.type == BTRFS_EXTENT_DATA_KEY)
3537			path->slots[0]--;
3538	}
3539
3540	while (start < i_size) {
3541		struct extent_buffer *leaf = path->nodes[0];
3542		struct btrfs_file_extent_item *extent;
3543		u64 extent_end;
3544		u8 type;
3545
3546		if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3547			ret = btrfs_next_leaf(root, path);
3548			if (ret < 0)
3549				goto out;
3550			else if (ret > 0)
3551				break;
3552
3553			leaf = path->nodes[0];
3554		}
3555
3556		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3557		if (key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY)
3558			break;
3559
3560		extent_end = btrfs_file_extent_end(path);
3561
3562		/*
3563		 * In the first iteration we may have a slot that points to an
3564		 * extent that ends before our start offset, so skip it.
3565		 */
3566		if (extent_end <= start) {
3567			path->slots[0]++;
3568			continue;
3569		}
3570
3571		/* We have an implicit hole, NO_HOLES feature is likely set. */
3572		if (last_extent_end < key.offset) {
3573			u64 search_start = last_extent_end;
3574			u64 found_start;
3575
3576			/*
3577			 * First iteration, @start matches @offset and it's
3578			 * within the hole.
3579			 */
3580			if (start == offset)
3581				search_start = offset;
3582
3583			found = find_desired_extent_in_hole(inode, whence,
3584							    delalloc_cached_state,
3585							    search_start,
3586							    key.offset - 1,
3587							    &found_start);
3588			if (found) {
3589				start = found_start;
3590				break;
3591			}
3592			/*
3593			 * Didn't find data or a hole (due to delalloc) in the
3594			 * implicit hole range, so need to analyze the extent.
3595			 */
3596		}
3597
3598		extent = btrfs_item_ptr(leaf, path->slots[0],
3599					struct btrfs_file_extent_item);
3600		type = btrfs_file_extent_type(leaf, extent);
3601
3602		/*
3603		 * Can't access the extent's disk_bytenr field if this is an
3604		 * inline extent, since at that offset, it's where the extent
3605		 * data starts.
3606		 */
3607		if (type == BTRFS_FILE_EXTENT_PREALLOC ||
3608		    (type == BTRFS_FILE_EXTENT_REG &&
3609		     btrfs_file_extent_disk_bytenr(leaf, extent) == 0)) {
3610			/*
3611			 * Explicit hole or prealloc extent, search for delalloc.
3612			 * A prealloc extent is treated like a hole.
3613			 */
3614			u64 search_start = key.offset;
3615			u64 found_start;
3616
3617			/*
3618			 * First iteration, @start matches @offset and it's
3619			 * within the hole.
3620			 */
3621			if (start == offset)
3622				search_start = offset;
3623
3624			found = find_desired_extent_in_hole(inode, whence,
3625							    delalloc_cached_state,
3626							    search_start,
3627							    extent_end - 1,
3628							    &found_start);
3629			if (found) {
3630				start = found_start;
3631				break;
3632			}
3633			/*
3634			 * Didn't find data or a hole (due to delalloc) in the
3635			 * implicit hole range, so need to analyze the next
3636			 * extent item.
3637			 */
3638		} else {
3639			/*
3640			 * Found a regular or inline extent.
3641			 * If we are seeking for data, adjust the start offset
3642			 * and stop, we're done.
3643			 */
3644			if (whence == SEEK_DATA) {
3645				start = max_t(u64, key.offset, offset);
3646				found = true;
3647				break;
3648			}
3649			/*
3650			 * Else, we are seeking for a hole, check the next file
3651			 * extent item.
3652			 */
3653		}
3654
3655		start = extent_end;
3656		last_extent_end = extent_end;
3657		path->slots[0]++;
3658		if (fatal_signal_pending(current)) {
3659			ret = -EINTR;
3660			goto out;
3661		}
3662		cond_resched();
3663	}
3664
3665	/* We have an implicit hole from the last extent found up to i_size. */
3666	if (!found && start < i_size) {
3667		found = find_desired_extent_in_hole(inode, whence,
3668						    delalloc_cached_state, start,
3669						    i_size - 1, &start);
3670		if (!found)
3671			start = i_size;
 
 
3672	}
3673
3674out:
3675	unlock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
3676	btrfs_free_path(path);
3677
3678	if (ret < 0)
3679		return ret;
3680
3681	if (whence == SEEK_DATA && start >= i_size)
3682		return -ENXIO;
3683
3684	return min_t(loff_t, start, i_size);
3685}
3686
3687static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
3688{
3689	struct inode *inode = file->f_mapping->host;
3690
3691	switch (whence) {
3692	default:
3693		return generic_file_llseek(file, offset, whence);
3694	case SEEK_DATA:
3695	case SEEK_HOLE:
3696		btrfs_inode_lock(BTRFS_I(inode), BTRFS_ILOCK_SHARED);
3697		offset = find_desired_extent(file, offset, whence);
3698		btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_SHARED);
3699		break;
3700	}
3701
3702	if (offset < 0)
3703		return offset;
3704
3705	return vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
3706}
3707
3708static int btrfs_file_open(struct inode *inode, struct file *filp)
3709{
3710	int ret;
3711
3712	filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC | FMODE_BUF_WASYNC;
3713
3714	ret = fsverity_file_open(inode, filp);
3715	if (ret)
3716		return ret;
3717	return generic_file_open(inode, filp);
3718}
3719
3720static int check_direct_read(struct btrfs_fs_info *fs_info,
3721			     const struct iov_iter *iter, loff_t offset)
3722{
3723	int ret;
3724	int i, seg;
3725
3726	ret = check_direct_IO(fs_info, iter, offset);
3727	if (ret < 0)
3728		return ret;
3729
3730	if (!iter_is_iovec(iter))
3731		return 0;
3732
3733	for (seg = 0; seg < iter->nr_segs; seg++)
3734		for (i = seg + 1; i < iter->nr_segs; i++)
3735			if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
3736				return -EINVAL;
3737	return 0;
3738}
3739
3740static ssize_t btrfs_direct_read(struct kiocb *iocb, struct iov_iter *to)
3741{
3742	struct inode *inode = file_inode(iocb->ki_filp);
3743	size_t prev_left = 0;
3744	ssize_t read = 0;
3745	ssize_t ret;
3746
3747	if (fsverity_active(inode))
3748		return 0;
3749
3750	if (check_direct_read(btrfs_sb(inode->i_sb), to, iocb->ki_pos))
3751		return 0;
3752
3753	btrfs_inode_lock(BTRFS_I(inode), BTRFS_ILOCK_SHARED);
3754again:
3755	/*
3756	 * This is similar to what we do for direct IO writes, see the comment
3757	 * at btrfs_direct_write(), but we also disable page faults in addition
3758	 * to disabling them only at the iov_iter level. This is because when
3759	 * reading from a hole or prealloc extent, iomap calls iov_iter_zero(),
3760	 * which can still trigger page fault ins despite having set ->nofault
3761	 * to true of our 'to' iov_iter.
3762	 *
3763	 * The difference to direct IO writes is that we deadlock when trying
3764	 * to lock the extent range in the inode's tree during he page reads
3765	 * triggered by the fault in (while for writes it is due to waiting for
3766	 * our own ordered extent). This is because for direct IO reads,
3767	 * btrfs_dio_iomap_begin() returns with the extent range locked, which
3768	 * is only unlocked in the endio callback (end_bio_extent_readpage()).
3769	 */
3770	pagefault_disable();
3771	to->nofault = true;
3772	ret = btrfs_dio_read(iocb, to, read);
3773	to->nofault = false;
3774	pagefault_enable();
3775
3776	/* No increment (+=) because iomap returns a cumulative value. */
3777	if (ret > 0)
3778		read = ret;
3779
3780	if (iov_iter_count(to) > 0 && (ret == -EFAULT || ret > 0)) {
3781		const size_t left = iov_iter_count(to);
3782
3783		if (left == prev_left) {
3784			/*
3785			 * We didn't make any progress since the last attempt,
3786			 * fallback to a buffered read for the remainder of the
3787			 * range. This is just to avoid any possibility of looping
3788			 * for too long.
3789			 */
3790			ret = read;
3791		} else {
3792			/*
3793			 * We made some progress since the last retry or this is
3794			 * the first time we are retrying. Fault in as many pages
3795			 * as possible and retry.
3796			 */
3797			fault_in_iov_iter_writeable(to, left);
3798			prev_left = left;
3799			goto again;
3800		}
3801	}
3802	btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_SHARED);
3803	return ret < 0 ? ret : read;
3804}
3805
3806static ssize_t btrfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
3807{
3808	ssize_t ret = 0;
3809
3810	if (iocb->ki_flags & IOCB_DIRECT) {
3811		ret = btrfs_direct_read(iocb, to);
3812		if (ret < 0 || !iov_iter_count(to) ||
3813		    iocb->ki_pos >= i_size_read(file_inode(iocb->ki_filp)))
3814			return ret;
3815	}
3816
3817	return filemap_read(iocb, to, ret);
3818}
3819
3820const struct file_operations btrfs_file_operations = {
3821	.llseek		= btrfs_file_llseek,
3822	.read_iter      = btrfs_file_read_iter,
3823	.splice_read	= generic_file_splice_read,
3824	.write_iter	= btrfs_file_write_iter,
3825	.splice_write	= iter_file_splice_write,
3826	.mmap		= btrfs_file_mmap,
3827	.open		= btrfs_file_open,
3828	.release	= btrfs_release_file,
3829	.get_unmapped_area = thp_get_unmapped_area,
3830	.fsync		= btrfs_sync_file,
3831	.fallocate	= btrfs_fallocate,
3832	.unlocked_ioctl	= btrfs_ioctl,
3833#ifdef CONFIG_COMPAT
3834	.compat_ioctl	= btrfs_compat_ioctl,
3835#endif
3836	.remap_file_range = btrfs_remap_file_range,
3837};
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3838
3839int btrfs_fdatawrite_range(struct inode *inode, loff_t start, loff_t end)
3840{
3841	int ret;
3842
3843	/*
3844	 * So with compression we will find and lock a dirty page and clear the
3845	 * first one as dirty, setup an async extent, and immediately return
3846	 * with the entire range locked but with nobody actually marked with
3847	 * writeback.  So we can't just filemap_write_and_wait_range() and
3848	 * expect it to work since it will just kick off a thread to do the
3849	 * actual work.  So we need to call filemap_fdatawrite_range _again_
3850	 * since it will wait on the page lock, which won't be unlocked until
3851	 * after the pages have been marked as writeback and so we're good to go
3852	 * from there.  We have to do this otherwise we'll miss the ordered
3853	 * extents and that results in badness.  Please Josef, do not think you
3854	 * know better and pull this out at some point in the future, it is
3855	 * right and you are wrong.
3856	 */
3857	ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
3858	if (!ret && test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
3859			     &BTRFS_I(inode)->runtime_flags))
3860		ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
3861
3862	return ret;
3863}