1/*
   2 * Copyright (C) 2007 Oracle.  All rights reserved.
   3 *
   4 * This program is free software; you can redistribute it and/or
   5 * modify it under the terms of the GNU General Public
   6 * License v2 as published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope that it will be useful,
   9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11 * General Public License for more details.
  12 *
  13 * You should have received a copy of the GNU General Public
  14 * License along with this program; if not, write to the
  15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16 * Boston, MA 021110-1307, USA.
  17 */
  18
  19#include <linux/fs.h>
  20#include <linux/pagemap.h>
  21#include <linux/highmem.h>
  22#include <linux/time.h>
  23#include <linux/init.h>
  24#include <linux/string.h>
  25#include <linux/backing-dev.h>
  26#include <linux/mpage.h>
  27#include <linux/falloc.h>
  28#include <linux/swap.h>
  29#include <linux/writeback.h>
  30#include <linux/statfs.h>
  31#include <linux/compat.h>
  32#include <linux/slab.h>
 
 
 
  33#include "ctree.h"
  34#include "disk-io.h"
  35#include "transaction.h"
  36#include "btrfs_inode.h"
  37#include "ioctl.h"
  38#include "print-tree.h"
  39#include "tree-log.h"
  40#include "locking.h"
  41#include "compat.h"
 
 
  42
 
  43/*
  44 * when auto defrag is enabled we
  45 * queue up these defrag structs to remember which
  46 * inodes need defragging passes
  47 */
  48struct inode_defrag {
  49	struct rb_node rb_node;
  50	/* objectid */
  51	u64 ino;
  52	/*
  53	 * transid where the defrag was added, we search for
  54	 * extents newer than this
  55	 */
  56	u64 transid;
  57
  58	/* root objectid */
  59	u64 root;
  60
  61	/* last offset we were able to defrag */
  62	u64 last_offset;
  63
  64	/* if we've wrapped around back to zero once already */
  65	int cycled;
  66};
  67
  68static int __compare_inode_defrag(struct inode_defrag *defrag1,
  69				  struct inode_defrag *defrag2)
  70{
  71	if (defrag1->root > defrag2->root)
  72		return 1;
  73	else if (defrag1->root < defrag2->root)
  74		return -1;
  75	else if (defrag1->ino > defrag2->ino)
  76		return 1;
  77	else if (defrag1->ino < defrag2->ino)
  78		return -1;
  79	else
  80		return 0;
  81}
  82
  83/* pop a record for an inode into the defrag tree.  The lock
  84 * must be held already
  85 *
  86 * If you're inserting a record for an older transid than an
  87 * existing record, the transid already in the tree is lowered
  88 *
  89 * If an existing record is found the defrag item you
  90 * pass in is freed
  91 */
  92static void __btrfs_add_inode_defrag(struct inode *inode,
  93				    struct inode_defrag *defrag)
  94{
  95	struct btrfs_root *root = BTRFS_I(inode)->root;
  96	struct inode_defrag *entry;
  97	struct rb_node **p;
  98	struct rb_node *parent = NULL;
  99	int ret;
 100
 101	p = &root->fs_info->defrag_inodes.rb_node;
 102	while (*p) {
 103		parent = *p;
 104		entry = rb_entry(parent, struct inode_defrag, rb_node);
 105
 106		ret = __compare_inode_defrag(defrag, entry);
 107		if (ret < 0)
 108			p = &parent->rb_left;
 109		else if (ret > 0)
 110			p = &parent->rb_right;
 111		else {
 112			/* if we're reinserting an entry for
 113			 * an old defrag run, make sure to
 114			 * lower the transid of our existing record
 115			 */
 116			if (defrag->transid < entry->transid)
 117				entry->transid = defrag->transid;
 118			if (defrag->last_offset > entry->last_offset)
 119				entry->last_offset = defrag->last_offset;
 120			goto exists;
 121		}
 122	}
 123	set_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
 124	rb_link_node(&defrag->rb_node, parent, p);
 125	rb_insert_color(&defrag->rb_node, &root->fs_info->defrag_inodes);
 126	return;
 
 127
 128exists:
 129	kfree(defrag);
 130	return;
 
 131
 
 
 
 
 132}
 133
 134/*
 135 * insert a defrag record for this inode if auto defrag is
 136 * enabled
 137 */
 138int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
 139			   struct inode *inode)
 140{
 141	struct btrfs_root *root = BTRFS_I(inode)->root;
 
 142	struct inode_defrag *defrag;
 143	u64 transid;
 
 144
 145	if (!btrfs_test_opt(root, AUTO_DEFRAG))
 146		return 0;
 147
 148	if (btrfs_fs_closing(root->fs_info))
 149		return 0;
 150
 151	if (test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags))
 152		return 0;
 153
 154	if (trans)
 155		transid = trans->transid;
 156	else
 157		transid = BTRFS_I(inode)->root->last_trans;
 158
 159	defrag = kzalloc(sizeof(*defrag), GFP_NOFS);
 160	if (!defrag)
 161		return -ENOMEM;
 162
 163	defrag->ino = btrfs_ino(inode);
 164	defrag->transid = transid;
 165	defrag->root = root->root_key.objectid;
 166
 167	spin_lock(&root->fs_info->defrag_inodes_lock);
 168	if (!test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags))
 169		__btrfs_add_inode_defrag(inode, defrag);
 170	else
 171		kfree(defrag);
 172	spin_unlock(&root->fs_info->defrag_inodes_lock);
 
 
 
 
 
 
 
 
 173	return 0;
 174}
 175
 176/*
 177 * must be called with the defrag_inodes lock held
 
 
 178 */
 179struct inode_defrag *btrfs_find_defrag_inode(struct btrfs_fs_info *info,
 180					     u64 root, u64 ino,
 181					     struct rb_node **next)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 182{
 183	struct inode_defrag *entry = NULL;
 184	struct inode_defrag tmp;
 185	struct rb_node *p;
 186	struct rb_node *parent = NULL;
 187	int ret;
 188
 189	tmp.ino = ino;
 190	tmp.root = root;
 191
 192	p = info->defrag_inodes.rb_node;
 
 193	while (p) {
 194		parent = p;
 195		entry = rb_entry(parent, struct inode_defrag, rb_node);
 196
 197		ret = __compare_inode_defrag(&tmp, entry);
 198		if (ret < 0)
 199			p = parent->rb_left;
 200		else if (ret > 0)
 201			p = parent->rb_right;
 202		else
 203			return entry;
 204	}
 205
 206	if (next) {
 207		while (parent && __compare_inode_defrag(&tmp, entry) > 0) {
 208			parent = rb_next(parent);
 209			entry = rb_entry(parent, struct inode_defrag, rb_node);
 210		}
 211		*next = parent;
 212	}
 213	return NULL;
 
 
 
 
 214}
 215
 216/*
 217 * run through the list of inodes in the FS that need
 218 * defragging
 219 */
 220int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
 221{
 222	struct inode_defrag *defrag;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 223	struct btrfs_root *inode_root;
 224	struct inode *inode;
 225	struct rb_node *n;
 226	struct btrfs_key key;
 227	struct btrfs_ioctl_defrag_range_args range;
 228	u64 first_ino = 0;
 229	u64 root_objectid = 0;
 230	int num_defrag;
 231	int defrag_batch = 1024;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 232
 
 
 233	memset(&range, 0, sizeof(range));
 234	range.len = (u64)-1;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 235
 236	atomic_inc(&fs_info->defrag_running);
 237	spin_lock(&fs_info->defrag_inodes_lock);
 238	while(1) {
 239		n = NULL;
 
 
 
 
 
 240
 241		/* find an inode to defrag */
 242		defrag = btrfs_find_defrag_inode(fs_info, root_objectid,
 243						 first_ino, &n);
 244		if (!defrag) {
 245			if (n) {
 246				defrag = rb_entry(n, struct inode_defrag,
 247						  rb_node);
 248			} else if (root_objectid || first_ino) {
 249				root_objectid = 0;
 250				first_ino = 0;
 251				continue;
 252			} else {
 253				break;
 254			}
 255		}
 256
 257		/* remove it from the rbtree */
 258		first_ino = defrag->ino + 1;
 259		root_objectid = defrag->root;
 260		rb_erase(&defrag->rb_node, &fs_info->defrag_inodes);
 261
 262		if (btrfs_fs_closing(fs_info))
 263			goto next_free;
 264
 265		spin_unlock(&fs_info->defrag_inodes_lock);
 266
 267		/* get the inode */
 268		key.objectid = defrag->root;
 269		btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
 270		key.offset = (u64)-1;
 271		inode_root = btrfs_read_fs_root_no_name(fs_info, &key);
 272		if (IS_ERR(inode_root))
 273			goto next;
 274
 275		key.objectid = defrag->ino;
 276		btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
 277		key.offset = 0;
 278
 279		inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL);
 280		if (IS_ERR(inode))
 281			goto next;
 282
 283		/* do a chunk of defrag */
 284		clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
 285		range.start = defrag->last_offset;
 286		num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
 287					       defrag_batch);
 288		/*
 289		 * if we filled the whole defrag batch, there
 290		 * must be more work to do.  Queue this defrag
 291		 * again
 292		 */
 293		if (num_defrag == defrag_batch) {
 294			defrag->last_offset = range.start;
 295			__btrfs_add_inode_defrag(inode, defrag);
 296			/*
 297			 * we don't want to kfree defrag, we added it back to
 298			 * the rbtree
 299			 */
 300			defrag = NULL;
 301		} else if (defrag->last_offset && !defrag->cycled) {
 302			/*
 303			 * we didn't fill our defrag batch, but
 304			 * we didn't start at zero.  Make sure we loop
 305			 * around to the start of the file.
 306			 */
 307			defrag->last_offset = 0;
 308			defrag->cycled = 1;
 309			__btrfs_add_inode_defrag(inode, defrag);
 310			defrag = NULL;
 311		}
 312
 313		iput(inode);
 314next:
 315		spin_lock(&fs_info->defrag_inodes_lock);
 316next_free:
 317		kfree(defrag);
 318	}
 319	spin_unlock(&fs_info->defrag_inodes_lock);
 320
 321	atomic_dec(&fs_info->defrag_running);
 322
 323	/*
 324	 * during unmount, we use the transaction_wait queue to
 325	 * wait for the defragger to stop
 326	 */
 327	wake_up(&fs_info->transaction_wait);
 328	return 0;
 329}
 330
 331/* simple helper to fault in pages and copy.  This should go away
 332 * and be replaced with calls into generic code.
 333 */
 334static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
 335					 size_t write_bytes,
 336					 struct page **prepared_pages,
 337					 struct iov_iter *i)
 338{
 339	size_t copied = 0;
 340	size_t total_copied = 0;
 341	int pg = 0;
 342	int offset = pos & (PAGE_CACHE_SIZE - 1);
 343
 344	while (write_bytes > 0) {
 345		size_t count = min_t(size_t,
 346				     PAGE_CACHE_SIZE - offset, write_bytes);
 347		struct page *page = prepared_pages[pg];
 348		/*
 349		 * Copy data from userspace to the current page
 350		 *
 351		 * Disable pagefault to avoid recursive lock since
 352		 * the pages are already locked
 353		 */
 354		pagefault_disable();
 355		copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
 356		pagefault_enable();
 357
 358		/* Flush processor's dcache for this page */
 359		flush_dcache_page(page);
 360
 361		/*
 362		 * if we get a partial write, we can end up with
 363		 * partially up to date pages.  These add
 364		 * a lot of complexity, so make sure they don't
 365		 * happen by forcing this copy to be retried.
 366		 *
 367		 * The rest of the btrfs_file_write code will fall
 368		 * back to page at a time copies after we return 0.
 369		 */
 370		if (!PageUptodate(page) && copied < count)
 371			copied = 0;
 372
 373		iov_iter_advance(i, copied);
 374		write_bytes -= copied;
 375		total_copied += copied;
 376
 377		/* Return to btrfs_file_aio_write to fault page */
 378		if (unlikely(copied == 0))
 379			break;
 380
 381		if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
 382			offset += copied;
 383		} else {
 384			pg++;
 385			offset = 0;
 386		}
 387	}
 388	return total_copied;
 389}
 390
 391/*
 392 * unlocks pages after btrfs_file_write is done with them
 393 */
 394void btrfs_drop_pages(struct page **pages, size_t num_pages)
 395{
 396	size_t i;
 397	for (i = 0; i < num_pages; i++) {
 398		/* page checked is some magic around finding pages that
 399		 * have been modified without going through btrfs_set_page_dirty
 400		 * clear it here
 
 
 401		 */
 402		ClearPageChecked(pages[i]);
 403		unlock_page(pages[i]);
 404		mark_page_accessed(pages[i]);
 405		page_cache_release(pages[i]);
 406	}
 407}
 408
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 409/*
 410 * after copy_from_user, pages need to be dirtied and we need to make
 411 * sure holes are created between the current EOF and the start of
 412 * any next extents (if required).
 413 *
 414 * this also makes the decision about creating an inline extent vs
 415 * doing real data extents, marking pages dirty and delalloc as required.
 416 */
 417int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode,
 418		      struct page **pages, size_t num_pages,
 419		      loff_t pos, size_t write_bytes,
 420		      struct extent_state **cached)
 421{
 
 422	int err = 0;
 423	int i;
 424	u64 num_bytes;
 425	u64 start_pos;
 426	u64 end_of_last_block;
 427	u64 end_pos = pos + write_bytes;
 428	loff_t isize = i_size_read(inode);
 
 429
 430	start_pos = pos & ~((u64)root->sectorsize - 1);
 431	num_bytes = (write_bytes + pos - start_pos +
 432		    root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
 433
 434	end_of_last_block = start_pos + num_bytes - 1;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 435	err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
 436					cached);
 437	if (err)
 438		return err;
 439
 440	for (i = 0; i < num_pages; i++) {
 441		struct page *p = pages[i];
 442		SetPageUptodate(p);
 443		ClearPageChecked(p);
 444		set_page_dirty(p);
 445	}
 446
 447	/*
 448	 * we've only changed i_size in ram, and we haven't updated
 449	 * the disk i_size.  There is no need to log the inode
 450	 * at this time.
 451	 */
 452	if (end_pos > isize)
 453		i_size_write(inode, end_pos);
 454	return 0;
 455}
 456
 457/*
 458 * this drops all the extents in the cache that intersect the range
 459 * [start, end].  Existing extents are split as required.
 460 */
 461int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
 462			    int skip_pinned)
 463{
 464	struct extent_map *em;
 465	struct extent_map *split = NULL;
 466	struct extent_map *split2 = NULL;
 467	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 468	u64 len = end - start + 1;
 
 469	int ret;
 470	int testend = 1;
 471	unsigned long flags;
 472	int compressed = 0;
 
 473
 474	WARN_ON(end < start);
 475	if (end == (u64)-1) {
 476		len = (u64)-1;
 477		testend = 0;
 478	}
 479	while (1) {
 
 
 
 480		if (!split)
 481			split = alloc_extent_map();
 482		if (!split2)
 483			split2 = alloc_extent_map();
 484		BUG_ON(!split || !split2); /* -ENOMEM */
 
 485
 486		write_lock(&em_tree->lock);
 487		em = lookup_extent_mapping(em_tree, start, len);
 488		if (!em) {
 489			write_unlock(&em_tree->lock);
 490			break;
 491		}
 492		flags = em->flags;
 
 493		if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
 494			if (testend && em->start + em->len >= start + len) {
 495				free_extent_map(em);
 496				write_unlock(&em_tree->lock);
 497				break;
 498			}
 499			start = em->start + em->len;
 500			if (testend)
 501				len = start + len - (em->start + em->len);
 502			free_extent_map(em);
 503			write_unlock(&em_tree->lock);
 504			continue;
 505		}
 506		compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 507		clear_bit(EXTENT_FLAG_PINNED, &em->flags);
 508		remove_extent_mapping(em_tree, em);
 
 
 
 509
 510		if (em->block_start < EXTENT_MAP_LAST_BYTE &&
 511		    em->start < start) {
 512			split->start = em->start;
 513			split->len = start - em->start;
 514			split->orig_start = em->orig_start;
 515			split->block_start = em->block_start;
 516
 517			if (compressed)
 518				split->block_len = em->block_len;
 519			else
 520				split->block_len = split->len;
 521
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 522			split->bdev = em->bdev;
 523			split->flags = flags;
 524			split->compress_type = em->compress_type;
 525			ret = add_extent_mapping(em_tree, split);
 526			BUG_ON(ret); /* Logic error */
 527			free_extent_map(split);
 528			split = split2;
 529			split2 = NULL;
 530		}
 531		if (em->block_start < EXTENT_MAP_LAST_BYTE &&
 532		    testend && em->start + em->len > start + len) {
 533			u64 diff = start + len - em->start;
 534
 535			split->start = start + len;
 536			split->len = em->start + em->len - (start + len);
 537			split->bdev = em->bdev;
 538			split->flags = flags;
 539			split->compress_type = em->compress_type;
 
 540
 541			if (compressed) {
 542				split->block_len = em->block_len;
 543				split->block_start = em->block_start;
 544				split->orig_start = em->orig_start;
 
 
 
 
 
 
 
 
 
 
 
 545			} else {
 546				split->block_len = split->len;
 547				split->block_start = em->block_start + diff;
 548				split->orig_start = split->start;
 
 
 
 549			}
 550
 551			ret = add_extent_mapping(em_tree, split);
 552			BUG_ON(ret); /* Logic error */
 
 
 
 
 
 
 553			free_extent_map(split);
 554			split = NULL;
 555		}
 
 
 
 556		write_unlock(&em_tree->lock);
 557
 558		/* once for us */
 559		free_extent_map(em);
 560		/* once for the tree*/
 561		free_extent_map(em);
 562	}
 563	if (split)
 564		free_extent_map(split);
 565	if (split2)
 566		free_extent_map(split2);
 567	return 0;
 568}
 569
 570/*
 571 * this is very complex, but the basic idea is to drop all extents
 572 * in the range start - end.  hint_block is filled in with a block number
 573 * that would be a good hint to the block allocator for this file.
 574 *
 575 * If an extent intersects the range but is not entirely inside the range
 576 * it is either truncated or split.  Anything entirely inside the range
 577 * is deleted from the tree.
 578 */
 579int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode,
 580		       u64 start, u64 end, u64 *hint_byte, int drop_cache)
 
 
 
 
 
 581{
 582	struct btrfs_root *root = BTRFS_I(inode)->root;
 583	struct extent_buffer *leaf;
 584	struct btrfs_file_extent_item *fi;
 585	struct btrfs_path *path;
 586	struct btrfs_key key;
 587	struct btrfs_key new_key;
 588	u64 ino = btrfs_ino(inode);
 589	u64 search_start = start;
 590	u64 disk_bytenr = 0;
 591	u64 num_bytes = 0;
 592	u64 extent_offset = 0;
 593	u64 extent_end = 0;
 
 594	int del_nr = 0;
 595	int del_slot = 0;
 596	int extent_type;
 597	int recow;
 598	int ret;
 599	int modify_tree = -1;
 
 
 
 600
 601	if (drop_cache)
 602		btrfs_drop_extent_cache(inode, start, end - 1, 0);
 603
 604	path = btrfs_alloc_path();
 605	if (!path)
 606		return -ENOMEM;
 607
 608	if (start >= BTRFS_I(inode)->disk_i_size)
 609		modify_tree = 0;
 610
 
 
 611	while (1) {
 612		recow = 0;
 613		ret = btrfs_lookup_file_extent(trans, root, path, ino,
 614					       search_start, modify_tree);
 615		if (ret < 0)
 616			break;
 617		if (ret > 0 && path->slots[0] > 0 && search_start == start) {
 618			leaf = path->nodes[0];
 619			btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
 620			if (key.objectid == ino &&
 621			    key.type == BTRFS_EXTENT_DATA_KEY)
 622				path->slots[0]--;
 623		}
 624		ret = 0;
 
 625next_slot:
 626		leaf = path->nodes[0];
 627		if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 628			BUG_ON(del_nr > 0);
 629			ret = btrfs_next_leaf(root, path);
 630			if (ret < 0)
 631				break;
 632			if (ret > 0) {
 633				ret = 0;
 634				break;
 635			}
 
 636			leaf = path->nodes[0];
 637			recow = 1;
 638		}
 639
 640		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 641		if (key.objectid > ino ||
 642		    key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
 
 
 
 
 
 
 
 
 643			break;
 644
 645		fi = btrfs_item_ptr(leaf, path->slots[0],
 646				    struct btrfs_file_extent_item);
 647		extent_type = btrfs_file_extent_type(leaf, fi);
 648
 649		if (extent_type == BTRFS_FILE_EXTENT_REG ||
 650		    extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
 651			disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
 652			num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
 653			extent_offset = btrfs_file_extent_offset(leaf, fi);
 654			extent_end = key.offset +
 655				btrfs_file_extent_num_bytes(leaf, fi);
 656		} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 657			extent_end = key.offset +
 658				btrfs_file_extent_inline_len(leaf, fi);
 
 659		} else {
 660			WARN_ON(1);
 661			extent_end = search_start;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 662		}
 663
 664		if (extent_end <= search_start) {
 665			path->slots[0]++;
 666			goto next_slot;
 667		}
 668
 
 669		search_start = max(key.offset, start);
 670		if (recow || !modify_tree) {
 671			modify_tree = -1;
 672			btrfs_release_path(path);
 673			continue;
 674		}
 675
 676		/*
 677		 *     | - range to drop - |
 678		 *  | -------- extent -------- |
 679		 */
 680		if (start > key.offset && end < extent_end) {
 681			BUG_ON(del_nr > 0);
 682			BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
 
 
 
 683
 684			memcpy(&new_key, &key, sizeof(new_key));
 685			new_key.offset = start;
 686			ret = btrfs_duplicate_item(trans, root, path,
 687						   &new_key);
 688			if (ret == -EAGAIN) {
 689				btrfs_release_path(path);
 690				continue;
 691			}
 692			if (ret < 0)
 693				break;
 694
 695			leaf = path->nodes[0];
 696			fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
 697					    struct btrfs_file_extent_item);
 698			btrfs_set_file_extent_num_bytes(leaf, fi,
 699							start - key.offset);
 700
 701			fi = btrfs_item_ptr(leaf, path->slots[0],
 702					    struct btrfs_file_extent_item);
 703
 704			extent_offset += start - key.offset;
 705			btrfs_set_file_extent_offset(leaf, fi, extent_offset);
 706			btrfs_set_file_extent_num_bytes(leaf, fi,
 707							extent_end - start);
 708			btrfs_mark_buffer_dirty(leaf);
 709
 710			if (disk_bytenr > 0) {
 711				ret = btrfs_inc_extent_ref(trans, root,
 712						disk_bytenr, num_bytes, 0,
 713						root->root_key.objectid,
 714						new_key.objectid,
 715						start - extent_offset, 0);
 716				BUG_ON(ret); /* -ENOMEM */
 717				*hint_byte = disk_bytenr;
 718			}
 719			key.offset = start;
 720		}
 721		/*
 
 
 
 
 
 
 722		 *  | ---- range to drop ----- |
 723		 *      | -------- extent -------- |
 724		 */
 725		if (start <= key.offset && end < extent_end) {
 726			BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
 
 
 
 727
 728			memcpy(&new_key, &key, sizeof(new_key));
 729			new_key.offset = end;
 730			btrfs_set_item_key_safe(trans, root, path, &new_key);
 731
 732			extent_offset += end - key.offset;
 733			btrfs_set_file_extent_offset(leaf, fi, extent_offset);
 734			btrfs_set_file_extent_num_bytes(leaf, fi,
 735							extent_end - end);
 736			btrfs_mark_buffer_dirty(leaf);
 737			if (disk_bytenr > 0) {
 738				inode_sub_bytes(inode, end - key.offset);
 739				*hint_byte = disk_bytenr;
 740			}
 741			break;
 742		}
 743
 744		search_start = extent_end;
 745		/*
 746		 *       | ---- range to drop ----- |
 747		 *  | -------- extent -------- |
 748		 */
 749		if (start > key.offset && end >= extent_end) {
 750			BUG_ON(del_nr > 0);
 751			BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
 
 
 
 752
 753			btrfs_set_file_extent_num_bytes(leaf, fi,
 754							start - key.offset);
 755			btrfs_mark_buffer_dirty(leaf);
 756			if (disk_bytenr > 0) {
 757				inode_sub_bytes(inode, extent_end - start);
 758				*hint_byte = disk_bytenr;
 759			}
 760			if (end == extent_end)
 761				break;
 762
 763			path->slots[0]++;
 764			goto next_slot;
 765		}
 766
 767		/*
 768		 *  | ---- range to drop ----- |
 769		 *    | ------ extent ------ |
 770		 */
 771		if (start <= key.offset && end >= extent_end) {
 
 772			if (del_nr == 0) {
 773				del_slot = path->slots[0];
 774				del_nr = 1;
 775			} else {
 776				BUG_ON(del_slot + del_nr != path->slots[0]);
 777				del_nr++;
 778			}
 779
 780			if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 
 781				inode_sub_bytes(inode,
 782						extent_end - key.offset);
 783				extent_end = ALIGN(extent_end,
 784						   root->sectorsize);
 785			} else if (disk_bytenr > 0) {
 786				ret = btrfs_free_extent(trans, root,
 787						disk_bytenr, num_bytes, 0,
 788						root->root_key.objectid,
 789						key.objectid, key.offset -
 790						extent_offset, 0);
 791				BUG_ON(ret); /* -ENOMEM */
 792				inode_sub_bytes(inode,
 793						extent_end - key.offset);
 794				*hint_byte = disk_bytenr;
 795			}
 796
 797			if (end == extent_end)
 798				break;
 799
 800			if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
 801				path->slots[0]++;
 802				goto next_slot;
 803			}
 804
 805			ret = btrfs_del_items(trans, root, path, del_slot,
 806					      del_nr);
 807			if (ret) {
 808				btrfs_abort_transaction(trans, root, ret);
 809				goto out;
 810			}
 811
 812			del_nr = 0;
 813			del_slot = 0;
 814
 815			btrfs_release_path(path);
 816			continue;
 817		}
 818
 819		BUG_ON(1);
 820	}
 821
 822	if (!ret && del_nr > 0) {
 
 
 
 
 
 
 
 823		ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
 824		if (ret)
 825			btrfs_abort_transaction(trans, root, ret);
 826	}
 827
 828out:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 829	btrfs_free_path(path);
 830	return ret;
 831}
 832
 833static int extent_mergeable(struct extent_buffer *leaf, int slot,
 834			    u64 objectid, u64 bytenr, u64 orig_offset,
 835			    u64 *start, u64 *end)
 836{
 837	struct btrfs_file_extent_item *fi;
 838	struct btrfs_key key;
 839	u64 extent_end;
 840
 841	if (slot < 0 || slot >= btrfs_header_nritems(leaf))
 842		return 0;
 843
 844	btrfs_item_key_to_cpu(leaf, &key, slot);
 845	if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
 846		return 0;
 847
 848	fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
 849	if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
 850	    btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
 851	    btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
 852	    btrfs_file_extent_compression(leaf, fi) ||
 853	    btrfs_file_extent_encryption(leaf, fi) ||
 854	    btrfs_file_extent_other_encoding(leaf, fi))
 855		return 0;
 856
 857	extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
 858	if ((*start && *start != key.offset) || (*end && *end != extent_end))
 859		return 0;
 860
 861	*start = key.offset;
 862	*end = extent_end;
 863	return 1;
 864}
 865
 866/*
 867 * Mark extent in the range start - end as written.
 868 *
 869 * This changes extent type from 'pre-allocated' to 'regular'. If only
 870 * part of extent is marked as written, the extent will be split into
 871 * two or three.
 872 */
 873int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
 874			      struct inode *inode, u64 start, u64 end)
 875{
 876	struct btrfs_root *root = BTRFS_I(inode)->root;
 
 877	struct extent_buffer *leaf;
 878	struct btrfs_path *path;
 879	struct btrfs_file_extent_item *fi;
 880	struct btrfs_key key;
 881	struct btrfs_key new_key;
 882	u64 bytenr;
 883	u64 num_bytes;
 884	u64 extent_end;
 885	u64 orig_offset;
 886	u64 other_start;
 887	u64 other_end;
 888	u64 split;
 889	int del_nr = 0;
 890	int del_slot = 0;
 891	int recow;
 892	int ret;
 893	u64 ino = btrfs_ino(inode);
 894
 895	btrfs_drop_extent_cache(inode, start, end - 1, 0);
 896
 897	path = btrfs_alloc_path();
 898	if (!path)
 899		return -ENOMEM;
 900again:
 901	recow = 0;
 902	split = start;
 903	key.objectid = ino;
 904	key.type = BTRFS_EXTENT_DATA_KEY;
 905	key.offset = split;
 906
 907	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 908	if (ret < 0)
 909		goto out;
 910	if (ret > 0 && path->slots[0] > 0)
 911		path->slots[0]--;
 912
 913	leaf = path->nodes[0];
 914	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 915	BUG_ON(key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY);
 
 
 
 
 
 916	fi = btrfs_item_ptr(leaf, path->slots[0],
 917			    struct btrfs_file_extent_item);
 918	BUG_ON(btrfs_file_extent_type(leaf, fi) !=
 919	       BTRFS_FILE_EXTENT_PREALLOC);
 
 
 
 920	extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
 921	BUG_ON(key.offset > start || extent_end < end);
 
 
 
 
 922
 923	bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
 924	num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
 925	orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
 926	memcpy(&new_key, &key, sizeof(new_key));
 927
 928	if (start == key.offset && end < extent_end) {
 929		other_start = 0;
 930		other_end = start;
 931		if (extent_mergeable(leaf, path->slots[0] - 1,
 932				     ino, bytenr, orig_offset,
 933				     &other_start, &other_end)) {
 934			new_key.offset = end;
 935			btrfs_set_item_key_safe(trans, root, path, &new_key);
 936			fi = btrfs_item_ptr(leaf, path->slots[0],
 937					    struct btrfs_file_extent_item);
 
 
 938			btrfs_set_file_extent_num_bytes(leaf, fi,
 939							extent_end - end);
 940			btrfs_set_file_extent_offset(leaf, fi,
 941						     end - orig_offset);
 942			fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
 943					    struct btrfs_file_extent_item);
 
 
 944			btrfs_set_file_extent_num_bytes(leaf, fi,
 945							end - other_start);
 946			btrfs_mark_buffer_dirty(leaf);
 947			goto out;
 948		}
 949	}
 950
 951	if (start > key.offset && end == extent_end) {
 952		other_start = end;
 953		other_end = 0;
 954		if (extent_mergeable(leaf, path->slots[0] + 1,
 955				     ino, bytenr, orig_offset,
 956				     &other_start, &other_end)) {
 957			fi = btrfs_item_ptr(leaf, path->slots[0],
 958					    struct btrfs_file_extent_item);
 959			btrfs_set_file_extent_num_bytes(leaf, fi,
 960							start - key.offset);
 
 
 961			path->slots[0]++;
 962			new_key.offset = start;
 963			btrfs_set_item_key_safe(trans, root, path, &new_key);
 964
 965			fi = btrfs_item_ptr(leaf, path->slots[0],
 966					    struct btrfs_file_extent_item);
 
 
 967			btrfs_set_file_extent_num_bytes(leaf, fi,
 968							other_end - start);
 969			btrfs_set_file_extent_offset(leaf, fi,
 970						     start - orig_offset);
 971			btrfs_mark_buffer_dirty(leaf);
 972			goto out;
 973		}
 974	}
 975
 976	while (start > key.offset || end < extent_end) {
 977		if (key.offset == start)
 978			split = end;
 979
 980		new_key.offset = split;
 981		ret = btrfs_duplicate_item(trans, root, path, &new_key);
 982		if (ret == -EAGAIN) {
 983			btrfs_release_path(path);
 984			goto again;
 985		}
 986		if (ret < 0) {
 987			btrfs_abort_transaction(trans, root, ret);
 988			goto out;
 989		}
 990
 991		leaf = path->nodes[0];
 992		fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
 993				    struct btrfs_file_extent_item);
 
 994		btrfs_set_file_extent_num_bytes(leaf, fi,
 995						split - key.offset);
 996
 997		fi = btrfs_item_ptr(leaf, path->slots[0],
 998				    struct btrfs_file_extent_item);
 999
 
1000		btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
1001		btrfs_set_file_extent_num_bytes(leaf, fi,
1002						extent_end - split);
1003		btrfs_mark_buffer_dirty(leaf);
1004
1005		ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
1006					   root->root_key.objectid,
1007					   ino, orig_offset, 0);
1008		BUG_ON(ret); /* -ENOMEM */
 
 
 
1009
1010		if (split == start) {
1011			key.offset = start;
1012		} else {
1013			BUG_ON(start != key.offset);
 
 
 
 
1014			path->slots[0]--;
1015			extent_end = end;
1016		}
1017		recow = 1;
1018	}
1019
1020	other_start = end;
1021	other_end = 0;
1022	if (extent_mergeable(leaf, path->slots[0] + 1,
1023			     ino, bytenr, orig_offset,
1024			     &other_start, &other_end)) {
1025		if (recow) {
1026			btrfs_release_path(path);
1027			goto again;
1028		}
1029		extent_end = other_end;
1030		del_slot = path->slots[0] + 1;
1031		del_nr++;
1032		ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1033					0, root->root_key.objectid,
1034					ino, orig_offset, 0);
1035		BUG_ON(ret); /* -ENOMEM */
 
 
 
1036	}
1037	other_start = 0;
1038	other_end = start;
1039	if (extent_mergeable(leaf, path->slots[0] - 1,
1040			     ino, bytenr, orig_offset,
1041			     &other_start, &other_end)) {
1042		if (recow) {
1043			btrfs_release_path(path);
1044			goto again;
1045		}
1046		key.offset = other_start;
1047		del_slot = path->slots[0];
1048		del_nr++;
1049		ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1050					0, root->root_key.objectid,
1051					ino, orig_offset, 0);
1052		BUG_ON(ret); /* -ENOMEM */
 
 
 
1053	}
1054	if (del_nr == 0) {
1055		fi = btrfs_item_ptr(leaf, path->slots[0],
1056			   struct btrfs_file_extent_item);
1057		btrfs_set_file_extent_type(leaf, fi,
1058					   BTRFS_FILE_EXTENT_REG);
 
1059		btrfs_mark_buffer_dirty(leaf);
1060	} else {
1061		fi = btrfs_item_ptr(leaf, del_slot - 1,
1062			   struct btrfs_file_extent_item);
1063		btrfs_set_file_extent_type(leaf, fi,
1064					   BTRFS_FILE_EXTENT_REG);
 
1065		btrfs_set_file_extent_num_bytes(leaf, fi,
1066						extent_end - key.offset);
1067		btrfs_mark_buffer_dirty(leaf);
1068
1069		ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
1070		if (ret < 0) {
1071			btrfs_abort_transaction(trans, root, ret);
1072			goto out;
1073		}
1074	}
1075out:
1076	btrfs_free_path(path);
1077	return 0;
1078}
1079
1080/*
1081 * on error we return an unlocked page and the error value
1082 * on success we return a locked page and 0
1083 */
1084static int prepare_uptodate_page(struct page *page, u64 pos,
 
1085				 bool force_uptodate)
1086{
1087	int ret = 0;
1088
1089	if (((pos & (PAGE_CACHE_SIZE - 1)) || force_uptodate) &&
1090	    !PageUptodate(page)) {
1091		ret = btrfs_readpage(NULL, page);
1092		if (ret)
1093			return ret;
1094		lock_page(page);
1095		if (!PageUptodate(page)) {
1096			unlock_page(page);
1097			return -EIO;
1098		}
 
 
 
 
1099	}
1100	return 0;
1101}
1102
1103/*
1104 * this gets pages into the page cache and locks them down, it also properly
1105 * waits for data=ordered extents to finish before allowing the pages to be
1106 * modified.
1107 */
1108static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
1109			 struct page **pages, size_t num_pages,
1110			 loff_t pos, unsigned long first_index,
1111			 size_t write_bytes, bool force_uptodate)
1112{
1113	struct extent_state *cached_state = NULL;
1114	int i;
1115	unsigned long index = pos >> PAGE_CACHE_SHIFT;
1116	struct inode *inode = fdentry(file)->d_inode;
1117	gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1118	int err = 0;
1119	int faili = 0;
1120	u64 start_pos;
1121	u64 last_pos;
1122
1123	start_pos = pos & ~((u64)root->sectorsize - 1);
1124	last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
1125
1126again:
1127	for (i = 0; i < num_pages; i++) {
 
1128		pages[i] = find_or_create_page(inode->i_mapping, index + i,
1129					       mask | __GFP_WRITE);
1130		if (!pages[i]) {
1131			faili = i - 1;
1132			err = -ENOMEM;
1133			goto fail;
1134		}
1135
1136		if (i == 0)
1137			err = prepare_uptodate_page(pages[i], pos,
1138						    force_uptodate);
1139		if (i == num_pages - 1)
1140			err = prepare_uptodate_page(pages[i],
1141						    pos + write_bytes, false);
1142		if (err) {
1143			page_cache_release(pages[i]);
 
 
 
 
1144			faili = i - 1;
1145			goto fail;
1146		}
1147		wait_on_page_writeback(pages[i]);
1148	}
1149	err = 0;
1150	if (start_pos < inode->i_size) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1151		struct btrfs_ordered_extent *ordered;
1152		lock_extent_bits(&BTRFS_I(inode)->io_tree,
1153				 start_pos, last_pos - 1, 0, &cached_state);
1154		ordered = btrfs_lookup_first_ordered_extent(inode,
1155							    last_pos - 1);
 
1156		if (ordered &&
1157		    ordered->file_offset + ordered->len > start_pos &&
1158		    ordered->file_offset < last_pos) {
1159			btrfs_put_ordered_extent(ordered);
1160			unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1161					     start_pos, last_pos - 1,
1162					     &cached_state, GFP_NOFS);
1163			for (i = 0; i < num_pages; i++) {
1164				unlock_page(pages[i]);
1165				page_cache_release(pages[i]);
1166			}
1167			btrfs_wait_ordered_range(inode, start_pos,
1168						 last_pos - start_pos);
1169			goto again;
 
1170		}
1171		if (ordered)
1172			btrfs_put_ordered_extent(ordered);
1173
1174		clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
1175				  last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
1176				  EXTENT_DO_ACCOUNTING, 0, 0, &cached_state,
1177				  GFP_NOFS);
1178		unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1179				     start_pos, last_pos - 1, &cached_state,
1180				     GFP_NOFS);
1181	}
 
1182	for (i = 0; i < num_pages; i++) {
1183		if (clear_page_dirty_for_io(pages[i]))
1184			account_page_redirty(pages[i]);
1185		set_page_extent_mapped(pages[i]);
1186		WARN_ON(!PageLocked(pages[i]));
1187	}
1188	return 0;
1189fail:
1190	while (faili >= 0) {
1191		unlock_page(pages[faili]);
1192		page_cache_release(pages[faili]);
1193		faili--;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1194	}
1195	return err;
1196
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1197}
1198
1199static noinline ssize_t __btrfs_buffered_write(struct file *file,
1200					       struct iov_iter *i,
1201					       loff_t pos)
1202{
1203	struct inode *inode = fdentry(file)->d_inode;
 
1204	struct btrfs_root *root = BTRFS_I(inode)->root;
1205	struct page **pages = NULL;
1206	unsigned long first_index;
 
 
 
 
1207	size_t num_written = 0;
1208	int nrptrs;
1209	int ret = 0;
 
1210	bool force_page_uptodate = false;
1211
1212	nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
1213		     PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
1214		     (sizeof(struct page *)));
1215	nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
1216	nrptrs = max(nrptrs, 8);
1217	pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
1218	if (!pages)
1219		return -ENOMEM;
1220
1221	first_index = pos >> PAGE_CACHE_SHIFT;
1222
1223	while (iov_iter_count(i) > 0) {
1224		size_t offset = pos & (PAGE_CACHE_SIZE - 1);
 
1225		size_t write_bytes = min(iov_iter_count(i),
1226					 nrptrs * (size_t)PAGE_CACHE_SIZE -
1227					 offset);
1228		size_t num_pages = (write_bytes + offset +
1229				    PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
 
1230		size_t dirty_pages;
1231		size_t copied;
 
 
 
1232
1233		WARN_ON(num_pages > nrptrs);
1234
1235		/*
1236		 * Fault pages before locking them in prepare_pages
1237		 * to avoid recursive lock
1238		 */
1239		if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
1240			ret = -EFAULT;
1241			break;
1242		}
1243
1244		ret = btrfs_delalloc_reserve_space(inode,
1245					num_pages << PAGE_CACHE_SHIFT);
1246		if (ret)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1247			break;
 
1248
 
 
1249		/*
1250		 * This is going to setup the pages array with the number of
1251		 * pages we want, so we don't really need to worry about the
1252		 * contents of pages from loop to loop
1253		 */
1254		ret = prepare_pages(root, file, pages, num_pages,
1255				    pos, first_index, write_bytes,
1256				    force_page_uptodate);
1257		if (ret) {
1258			btrfs_delalloc_release_space(inode,
1259					num_pages << PAGE_CACHE_SHIFT);
 
 
 
 
 
 
 
 
 
 
 
 
 
1260			break;
1261		}
1262
1263		copied = btrfs_copy_from_user(pos, num_pages,
1264					   write_bytes, pages, i);
 
 
 
 
1265
1266		/*
1267		 * if we have trouble faulting in the pages, fall
1268		 * back to one page at a time
1269		 */
1270		if (copied < write_bytes)
1271			nrptrs = 1;
1272
1273		if (copied == 0) {
1274			force_page_uptodate = true;
 
1275			dirty_pages = 0;
1276		} else {
1277			force_page_uptodate = false;
1278			dirty_pages = (copied + offset +
1279				       PAGE_CACHE_SIZE - 1) >>
1280				       PAGE_CACHE_SHIFT;
1281		}
1282
1283		/*
1284		 * If we had a short copy we need to release the excess delaloc
1285		 * bytes we reserved.  We need to increment outstanding_extents
1286		 * because btrfs_delalloc_release_space will decrement it, but
1287		 * we still have an outstanding extent for the chunk we actually
1288		 * managed to copy.
1289		 */
1290		if (num_pages > dirty_pages) {
1291			if (copied > 0) {
1292				spin_lock(&BTRFS_I(inode)->lock);
1293				BTRFS_I(inode)->outstanding_extents++;
1294				spin_unlock(&BTRFS_I(inode)->lock);
1295			}
1296			btrfs_delalloc_release_space(inode,
1297					(num_pages - dirty_pages) <<
1298					PAGE_CACHE_SHIFT);
1299		}
1300
1301		if (copied > 0) {
1302			ret = btrfs_dirty_pages(root, inode, pages,
1303						dirty_pages, pos, copied,
1304						NULL);
1305			if (ret) {
1306				btrfs_delalloc_release_space(inode,
1307					dirty_pages << PAGE_CACHE_SHIFT);
1308				btrfs_drop_pages(pages, num_pages);
1309				break;
1310			}
1311		}
1312
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1313		btrfs_drop_pages(pages, num_pages);
1314
1315		cond_resched();
1316
1317		balance_dirty_pages_ratelimited_nr(inode->i_mapping,
1318						   dirty_pages);
1319		if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1320			btrfs_btree_balance_dirty(root, 1);
1321
1322		pos += copied;
1323		num_written += copied;
1324	}
1325
1326	kfree(pages);
1327
 
 
 
 
 
 
 
 
 
 
 
 
 
1328	return num_written ? num_written : ret;
1329}
1330
1331static ssize_t __btrfs_direct_write(struct kiocb *iocb,
1332				    const struct iovec *iov,
1333				    unsigned long nr_segs, loff_t pos,
1334				    loff_t *ppos, size_t count, size_t ocount)
1335{
1336	struct file *file = iocb->ki_filp;
1337	struct iov_iter i;
 
1338	ssize_t written;
1339	ssize_t written_buffered;
1340	loff_t endbyte;
1341	int err;
1342
1343	written = generic_file_direct_write(iocb, iov, &nr_segs, pos, ppos,
1344					    count, ocount);
1345
1346	if (written < 0 || written == count)
1347		return written;
1348
1349	pos += written;
1350	count -= written;
1351	iov_iter_init(&i, iov, nr_segs, count, written);
1352	written_buffered = __btrfs_buffered_write(file, &i, pos);
1353	if (written_buffered < 0) {
1354		err = written_buffered;
1355		goto out;
1356	}
 
 
 
 
1357	endbyte = pos + written_buffered - 1;
1358	err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
 
 
 
1359	if (err)
1360		goto out;
1361	written += written_buffered;
1362	*ppos = pos + written_buffered;
1363	invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT,
1364				 endbyte >> PAGE_CACHE_SHIFT);
1365out:
1366	return written ? written : err;
1367}
1368
1369static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
1370				    const struct iovec *iov,
1371				    unsigned long nr_segs, loff_t pos)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1372{
1373	struct file *file = iocb->ki_filp;
1374	struct inode *inode = fdentry(file)->d_inode;
 
1375	struct btrfs_root *root = BTRFS_I(inode)->root;
1376	loff_t *ppos = &iocb->ki_pos;
1377	u64 start_pos;
 
1378	ssize_t num_written = 0;
1379	ssize_t err = 0;
1380	size_t count, ocount;
1381
1382	vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
 
 
1383
1384	mutex_lock(&inode->i_mutex);
 
 
1385
1386	err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
1387	if (err) {
1388		mutex_unlock(&inode->i_mutex);
1389		goto out;
1390	}
1391	count = ocount;
1392
1393	current->backing_dev_info = inode->i_mapping->backing_dev_info;
1394	err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1395	if (err) {
1396		mutex_unlock(&inode->i_mutex);
1397		goto out;
1398	}
1399
1400	if (count == 0) {
1401		mutex_unlock(&inode->i_mutex);
1402		goto out;
 
 
 
 
 
 
 
 
 
1403	}
1404
1405	err = file_remove_suid(file);
 
1406	if (err) {
1407		mutex_unlock(&inode->i_mutex);
1408		goto out;
1409	}
1410
1411	/*
1412	 * If BTRFS flips readonly due to some impossible error
1413	 * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
1414	 * although we have opened a file as writable, we have
1415	 * to stop this write operation to ensure FS consistency.
1416	 */
1417	if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
1418		mutex_unlock(&inode->i_mutex);
1419		err = -EROFS;
1420		goto out;
1421	}
1422
1423	err = file_update_time(file);
1424	if (err) {
1425		mutex_unlock(&inode->i_mutex);
1426		goto out;
1427	}
 
 
1428
1429	start_pos = round_down(pos, root->sectorsize);
1430	if (start_pos > i_size_read(inode)) {
1431		err = btrfs_cont_expand(inode, i_size_read(inode), start_pos);
 
 
 
 
1432		if (err) {
1433			mutex_unlock(&inode->i_mutex);
1434			goto out;
1435		}
 
 
1436	}
1437
1438	if (unlikely(file->f_flags & O_DIRECT)) {
1439		num_written = __btrfs_direct_write(iocb, iov, nr_segs,
1440						   pos, ppos, count, ocount);
1441	} else {
1442		struct iov_iter i;
1443
1444		iov_iter_init(&i, iov, nr_segs, count, num_written);
1445
1446		num_written = __btrfs_buffered_write(file, &i, pos);
 
 
 
1447		if (num_written > 0)
1448			*ppos = pos + num_written;
 
 
 
1449	}
1450
1451	mutex_unlock(&inode->i_mutex);
1452
1453	/*
1454	 * we want to make sure fsync finds this change
1455	 * but we haven't joined a transaction running right now.
1456	 *
1457	 * Later on, someone is sure to update the inode and get the
1458	 * real transid recorded.
1459	 *
1460	 * We set last_trans now to the fs_info generation + 1,
1461	 * this will either be one more than the running transaction
1462	 * or the generation used for the next transaction if there isn't
1463	 * one running right now.
1464	 */
1465	BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1466	if (num_written > 0 || num_written == -EIOCBQUEUED) {
1467		err = generic_write_sync(file, pos, num_written);
1468		if (err < 0 && num_written > 0)
1469			num_written = err;
1470	}
1471out:
1472	current->backing_dev_info = NULL;
1473	return num_written ? num_written : err;
1474}
1475
1476int btrfs_release_file(struct inode *inode, struct file *filp)
1477{
 
 
 
 
 
 
 
1478	/*
1479	 * ordered_data_close is set by settattr when we are about to truncate
1480	 * a file from a non-zero size to a zero size.  This tries to
1481	 * flush down new bytes that may have been written if the
1482	 * application were using truncate to replace a file in place.
1483	 */
1484	if (test_and_clear_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
1485			       &BTRFS_I(inode)->runtime_flags)) {
1486		btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
1487		if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
1488			filemap_flush(inode->i_mapping);
1489	}
1490	if (filp->private_data)
1491		btrfs_ioctl_trans_end(filp);
1492	return 0;
1493}
1494
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1495/*
1496 * fsync call for both files and directories.  This logs the inode into
1497 * the tree log instead of forcing full commits whenever possible.
1498 *
1499 * It needs to call filemap_fdatawait so that all ordered extent updates are
1500 * in the metadata btree are up to date for copying to the log.
1501 *
1502 * It drops the inode mutex before doing the tree log commit.  This is an
1503 * important optimization for directories because holding the mutex prevents
1504 * new operations on the dir while we write to disk.
1505 */
1506int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
1507{
1508	struct dentry *dentry = file->f_path.dentry;
1509	struct inode *inode = dentry->d_inode;
 
1510	struct btrfs_root *root = BTRFS_I(inode)->root;
1511	int ret = 0;
1512	struct btrfs_trans_handle *trans;
 
 
 
 
1513
 
 
 
 
 
1514	trace_btrfs_sync_file(file, datasync);
1515
1516	mutex_lock(&inode->i_mutex);
1517
1518	/*
1519	 * we wait first, since the writeback may change the inode, also wait
1520	 * ordered range does a filemape_write_and_wait_range which is why we
1521	 * don't do it above like other file systems.
 
1522	 */
1523	root->log_batch++;
1524	btrfs_wait_ordered_range(inode, start, end);
1525	root->log_batch++;
1526
 
 
 
 
1527	/*
1528	 * check the transaction that last modified this inode
1529	 * and see if its already been committed
1530	 */
1531	if (!BTRFS_I(inode)->last_trans) {
1532		mutex_unlock(&inode->i_mutex);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1533		goto out;
1534	}
 
1535
1536	/*
1537	 * if the last transaction that changed this file was before
1538	 * the current transaction, we can bail out now without any
1539	 * syncing
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1540	 */
1541	smp_mb();
1542	if (btrfs_inode_in_log(inode, root->fs_info->generation) ||
1543	    BTRFS_I(inode)->last_trans <=
1544	    root->fs_info->last_trans_committed) {
1545		BTRFS_I(inode)->last_trans = 0;
1546		mutex_unlock(&inode->i_mutex);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1547		goto out;
1548	}
1549
1550	/*
1551	 * ok we haven't committed the transaction yet, lets do a commit
 
 
 
 
 
 
 
 
1552	 */
1553	if (file->private_data)
1554		btrfs_ioctl_trans_end(file);
1555
1556	trans = btrfs_start_transaction(root, 0);
1557	if (IS_ERR(trans)) {
1558		ret = PTR_ERR(trans);
1559		mutex_unlock(&inode->i_mutex);
1560		goto out;
1561	}
 
1562
1563	ret = btrfs_log_dentry_safe(trans, root, dentry);
1564	if (ret < 0) {
1565		mutex_unlock(&inode->i_mutex);
1566		goto out;
1567	}
1568
1569	/* we've logged all the items and now have a consistent
1570	 * version of the file in the log.  It is possible that
1571	 * someone will come in and modify the file, but that's
1572	 * fine because the log is consistent on disk, and we
1573	 * have references to all of the file's extents
1574	 *
1575	 * It is possible that someone will come in and log the
1576	 * file again, but that will end up using the synchronization
1577	 * inside btrfs_sync_log to keep things safe.
1578	 */
1579	mutex_unlock(&inode->i_mutex);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1580
1581	if (ret != BTRFS_NO_LOG_SYNC) {
1582		if (ret > 0) {
1583			ret = btrfs_commit_transaction(trans, root);
1584		} else {
1585			ret = btrfs_sync_log(trans, root);
1586			if (ret == 0)
1587				ret = btrfs_end_transaction(trans, root);
1588			else
1589				ret = btrfs_commit_transaction(trans, root);
1590		}
 
 
 
 
 
 
 
 
1591	} else {
1592		ret = btrfs_end_transaction(trans, root);
1593	}
1594out:
 
 
 
 
1595	return ret > 0 ? -EIO : ret;
1596}
1597
1598static const struct vm_operations_struct btrfs_file_vm_ops = {
1599	.fault		= filemap_fault,
 
1600	.page_mkwrite	= btrfs_page_mkwrite,
1601};
1602
1603static int btrfs_file_mmap(struct file	*filp, struct vm_area_struct *vma)
1604{
1605	struct address_space *mapping = filp->f_mapping;
1606
1607	if (!mapping->a_ops->readpage)
1608		return -ENOEXEC;
1609
1610	file_accessed(filp);
1611	vma->vm_ops = &btrfs_file_vm_ops;
1612	vma->vm_flags |= VM_CAN_NONLINEAR;
1613
1614	return 0;
1615}
1616
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1617static long btrfs_fallocate(struct file *file, int mode,
1618			    loff_t offset, loff_t len)
1619{
1620	struct inode *inode = file->f_path.dentry->d_inode;
1621	struct extent_state *cached_state = NULL;
 
 
 
 
1622	u64 cur_offset;
1623	u64 last_byte;
1624	u64 alloc_start;
1625	u64 alloc_end;
1626	u64 alloc_hint = 0;
1627	u64 locked_end;
1628	u64 mask = BTRFS_I(inode)->root->sectorsize - 1;
1629	struct extent_map *em;
 
1630	int ret;
1631
1632	alloc_start = offset & ~mask;
1633	alloc_end =  (offset + len + mask) & ~mask;
 
1634
1635	/* We only support the FALLOC_FL_KEEP_SIZE mode */
1636	if (mode & ~FALLOC_FL_KEEP_SIZE)
 
1637		return -EOPNOTSUPP;
1638
1639	/*
1640	 * Make sure we have enough space before we do the
1641	 * allocation.
1642	 */
1643	ret = btrfs_check_data_free_space(inode, len);
1644	if (ret)
1645		return ret;
1646
1647	/*
1648	 * wait for ordered IO before we have any locks.  We'll loop again
1649	 * below with the locks held.
 
1650	 */
1651	btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start);
 
 
 
 
 
1652
1653	mutex_lock(&inode->i_mutex);
1654	ret = inode_newsize_ok(inode, alloc_end);
1655	if (ret)
1656		goto out;
1657
 
 
 
 
 
 
 
 
 
 
 
 
 
1658	if (alloc_start > inode->i_size) {
1659		ret = btrfs_cont_expand(inode, i_size_read(inode),
1660					alloc_start);
1661		if (ret)
1662			goto out;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1663	}
1664
1665	locked_end = alloc_end - 1;
1666	while (1) {
1667		struct btrfs_ordered_extent *ordered;
1668
1669		/* the extent lock is ordered inside the running
1670		 * transaction
1671		 */
1672		lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
1673				 locked_end, 0, &cached_state);
1674		ordered = btrfs_lookup_first_ordered_extent(inode,
1675							    alloc_end - 1);
1676		if (ordered &&
1677		    ordered->file_offset + ordered->len > alloc_start &&
1678		    ordered->file_offset < alloc_end) {
1679			btrfs_put_ordered_extent(ordered);
1680			unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1681					     alloc_start, locked_end,
1682					     &cached_state, GFP_NOFS);
1683			/*
1684			 * we can't wait on the range with the transaction
1685			 * running or with the extent lock held
1686			 */
1687			btrfs_wait_ordered_range(inode, alloc_start,
1688						 alloc_end - alloc_start);
 
 
1689		} else {
1690			if (ordered)
1691				btrfs_put_ordered_extent(ordered);
1692			break;
1693		}
1694	}
1695
1696	cur_offset = alloc_start;
1697	while (1) {
1698		u64 actual_end;
1699
1700		em = btrfs_get_extent(inode, NULL, 0, cur_offset,
1701				      alloc_end - cur_offset, 0);
1702		if (IS_ERR_OR_NULL(em)) {
1703			if (!em)
1704				ret = -ENOMEM;
1705			else
1706				ret = PTR_ERR(em);
1707			break;
1708		}
1709		last_byte = min(extent_map_end(em), alloc_end);
1710		actual_end = min_t(u64, extent_map_end(em), offset + len);
1711		last_byte = (last_byte + mask) & ~mask;
1712
1713		if (em->block_start == EXTENT_MAP_HOLE ||
1714		    (cur_offset >= inode->i_size &&
1715		     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
1716			ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
1717							last_byte - cur_offset,
1718							1 << inode->i_blkbits,
1719							offset + len,
1720							&alloc_hint);
1721
 
 
1722			if (ret < 0) {
1723				free_extent_map(em);
1724				break;
1725			}
1726		} else if (actual_end > inode->i_size &&
1727			   !(mode & FALLOC_FL_KEEP_SIZE)) {
1728			/*
1729			 * We didn't need to allocate any more space, but we
1730			 * still extended the size of the file so we need to
1731			 * update i_size.
1732			 */
1733			inode->i_ctime = CURRENT_TIME;
1734			i_size_write(inode, actual_end);
1735			btrfs_ordered_update_i_size(inode, actual_end, NULL);
1736		}
1737		free_extent_map(em);
1738
1739		cur_offset = last_byte;
1740		if (cur_offset >= alloc_end) {
1741			ret = 0;
1742			break;
1743		}
1744	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1745	unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
1746			     &cached_state, GFP_NOFS);
1747out:
1748	mutex_unlock(&inode->i_mutex);
1749	/* Let go of our reservation. */
1750	btrfs_free_reserved_data_space(inode, len);
 
 
 
1751	return ret;
1752}
1753
1754static int find_desired_extent(struct inode *inode, loff_t *offset, int origin)
1755{
1756	struct btrfs_root *root = BTRFS_I(inode)->root;
1757	struct extent_map *em;
1758	struct extent_state *cached_state = NULL;
1759	u64 lockstart = *offset;
1760	u64 lockend = i_size_read(inode);
1761	u64 start = *offset;
1762	u64 orig_start = *offset;
1763	u64 len = i_size_read(inode);
1764	u64 last_end = 0;
1765	int ret = 0;
1766
1767	lockend = max_t(u64, root->sectorsize, lockend);
1768	if (lockend <= lockstart)
1769		lockend = lockstart + root->sectorsize;
1770
1771	len = lockend - lockstart + 1;
1772
1773	len = max_t(u64, len, root->sectorsize);
1774	if (inode->i_size == 0)
1775		return -ENXIO;
1776
1777	lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend, 0,
1778			 &cached_state);
1779
1780	/*
1781	 * Delalloc is such a pain.  If we have a hole and we have pending
1782	 * delalloc for a portion of the hole we will get back a hole that
1783	 * exists for the entire range since it hasn't been actually written
1784	 * yet.  So to take care of this case we need to look for an extent just
1785	 * before the position we want in case there is outstanding delalloc
1786	 * going on here.
1787	 */
1788	if (origin == SEEK_HOLE && start != 0) {
1789		if (start <= root->sectorsize)
1790			em = btrfs_get_extent_fiemap(inode, NULL, 0, 0,
1791						     root->sectorsize, 0);
1792		else
1793			em = btrfs_get_extent_fiemap(inode, NULL, 0,
1794						     start - root->sectorsize,
1795						     root->sectorsize, 0);
1796		if (IS_ERR(em)) {
1797			ret = PTR_ERR(em);
1798			goto out;
1799		}
1800		last_end = em->start + em->len;
1801		if (em->block_start == EXTENT_MAP_DELALLOC)
1802			last_end = min_t(u64, last_end, inode->i_size);
1803		free_extent_map(em);
1804	}
1805
1806	while (1) {
1807		em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0);
 
 
 
 
 
 
 
 
 
 
 
 
1808		if (IS_ERR(em)) {
1809			ret = PTR_ERR(em);
 
1810			break;
1811		}
1812
1813		if (em->block_start == EXTENT_MAP_HOLE) {
1814			if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
1815				if (last_end <= orig_start) {
1816					free_extent_map(em);
1817					ret = -ENXIO;
1818					break;
1819				}
1820			}
1821
1822			if (origin == SEEK_HOLE) {
1823				*offset = start;
1824				free_extent_map(em);
1825				break;
1826			}
1827		} else {
1828			if (origin == SEEK_DATA) {
1829				if (em->block_start == EXTENT_MAP_DELALLOC) {
1830					if (start >= inode->i_size) {
1831						free_extent_map(em);
1832						ret = -ENXIO;
1833						break;
1834					}
1835				}
1836
1837				*offset = start;
1838				free_extent_map(em);
1839				break;
1840			}
1841		}
1842
1843		start = em->start + em->len;
1844		last_end = em->start + em->len;
1845
1846		if (em->block_start == EXTENT_MAP_DELALLOC)
1847			last_end = min_t(u64, last_end, inode->i_size);
1848
1849		if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
1850			free_extent_map(em);
1851			ret = -ENXIO;
1852			break;
1853		}
1854		free_extent_map(em);
 
1855		cond_resched();
1856	}
1857	if (!ret)
1858		*offset = min(*offset, inode->i_size);
1859out:
 
 
 
 
1860	unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
1861			     &cached_state, GFP_NOFS);
1862	return ret;
1863}
1864
1865static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int origin)
1866{
1867	struct inode *inode = file->f_mapping->host;
1868	int ret;
1869
1870	mutex_lock(&inode->i_mutex);
1871	switch (origin) {
1872	case SEEK_END:
1873	case SEEK_CUR:
1874		offset = generic_file_llseek(file, offset, origin);
1875		goto out;
1876	case SEEK_DATA:
1877	case SEEK_HOLE:
1878		if (offset >= i_size_read(inode)) {
1879			mutex_unlock(&inode->i_mutex);
1880			return -ENXIO;
1881		}
1882
1883		ret = find_desired_extent(inode, &offset, origin);
1884		if (ret) {
1885			mutex_unlock(&inode->i_mutex);
1886			return ret;
1887		}
1888	}
1889
1890	if (offset < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET)) {
1891		offset = -EINVAL;
1892		goto out;
1893	}
1894	if (offset > inode->i_sb->s_maxbytes) {
1895		offset = -EINVAL;
1896		goto out;
1897	}
1898
1899	/* Special lock needed here? */
1900	if (offset != file->f_pos) {
1901		file->f_pos = offset;
1902		file->f_version = 0;
1903	}
1904out:
1905	mutex_unlock(&inode->i_mutex);
1906	return offset;
1907}
1908
 
 
 
 
 
 
1909const struct file_operations btrfs_file_operations = {
1910	.llseek		= btrfs_file_llseek,
1911	.read		= do_sync_read,
1912	.write		= do_sync_write,
1913	.aio_read       = generic_file_aio_read,
1914	.splice_read	= generic_file_splice_read,
1915	.aio_write	= btrfs_file_aio_write,
1916	.mmap		= btrfs_file_mmap,
1917	.open		= generic_file_open,
1918	.release	= btrfs_release_file,
1919	.fsync		= btrfs_sync_file,
1920	.fallocate	= btrfs_fallocate,
1921	.unlocked_ioctl	= btrfs_ioctl,
1922#ifdef CONFIG_COMPAT
1923	.compat_ioctl	= btrfs_ioctl,
1924#endif
 
 
1925};