file.c 79.4 KB
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/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

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#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/backing-dev.h>
#include <linux/mpage.h>
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#include <linux/falloc.h>
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#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/statfs.h>
#include <linux/compat.h>
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#include <linux/slab.h>
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#include <linux/btrfs.h>
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#include <linux/uio.h>
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#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "btrfs_inode.h"
#include "print-tree.h"
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#include "tree-log.h"
#include "locking.h"
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#include "volumes.h"
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#include "qgroup.h"
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static struct kmem_cache *btrfs_inode_defrag_cachep;
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/*
 * when auto defrag is enabled we
 * queue up these defrag structs to remember which
 * inodes need defragging passes
 */
struct inode_defrag {
	struct rb_node rb_node;
	/* objectid */
	u64 ino;
	/*
	 * transid where the defrag was added, we search for
	 * extents newer than this
	 */
	u64 transid;

	/* root objectid */
	u64 root;

	/* last offset we were able to defrag */
	u64 last_offset;

	/* if we've wrapped around back to zero once already */
	int cycled;
};

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static int __compare_inode_defrag(struct inode_defrag *defrag1,
				  struct inode_defrag *defrag2)
{
	if (defrag1->root > defrag2->root)
		return 1;
	else if (defrag1->root < defrag2->root)
		return -1;
	else if (defrag1->ino > defrag2->ino)
		return 1;
	else if (defrag1->ino < defrag2->ino)
		return -1;
	else
		return 0;
}

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/* pop a record for an inode into the defrag tree.  The lock
 * must be held already
 *
 * If you're inserting a record for an older transid than an
 * existing record, the transid already in the tree is lowered
 *
 * If an existing record is found the defrag item you
 * pass in is freed
 */
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static int __btrfs_add_inode_defrag(struct inode *inode,
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				    struct inode_defrag *defrag)
{
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct inode_defrag *entry;
	struct rb_node **p;
	struct rb_node *parent = NULL;
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	int ret;
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	p = &root->fs_info->defrag_inodes.rb_node;
	while (*p) {
		parent = *p;
		entry = rb_entry(parent, struct inode_defrag, rb_node);

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		ret = __compare_inode_defrag(defrag, entry);
		if (ret < 0)
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			p = &parent->rb_left;
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		else if (ret > 0)
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			p = &parent->rb_right;
		else {
			/* if we're reinserting an entry for
			 * an old defrag run, make sure to
			 * lower the transid of our existing record
			 */
			if (defrag->transid < entry->transid)
				entry->transid = defrag->transid;
			if (defrag->last_offset > entry->last_offset)
				entry->last_offset = defrag->last_offset;
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			return -EEXIST;
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		}
	}
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	set_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
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	rb_link_node(&defrag->rb_node, parent, p);
	rb_insert_color(&defrag->rb_node, &root->fs_info->defrag_inodes);
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	return 0;
}
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static inline int __need_auto_defrag(struct btrfs_root *root)
{
	if (!btrfs_test_opt(root, AUTO_DEFRAG))
		return 0;

	if (btrfs_fs_closing(root->fs_info))
		return 0;
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	return 1;
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}

/*
 * insert a defrag record for this inode if auto defrag is
 * enabled
 */
int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
			   struct inode *inode)
{
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct inode_defrag *defrag;
	u64 transid;
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	int ret;
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	if (!__need_auto_defrag(root))
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		return 0;

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	if (test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags))
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		return 0;

	if (trans)
		transid = trans->transid;
	else
		transid = BTRFS_I(inode)->root->last_trans;

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	defrag = kmem_cache_zalloc(btrfs_inode_defrag_cachep, GFP_NOFS);
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	if (!defrag)
		return -ENOMEM;

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	defrag->ino = btrfs_ino(inode);
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	defrag->transid = transid;
	defrag->root = root->root_key.objectid;

	spin_lock(&root->fs_info->defrag_inodes_lock);
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	if (!test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags)) {
		/*
		 * If we set IN_DEFRAG flag and evict the inode from memory,
		 * and then re-read this inode, this new inode doesn't have
		 * IN_DEFRAG flag. At the case, we may find the existed defrag.
		 */
		ret = __btrfs_add_inode_defrag(inode, defrag);
		if (ret)
			kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
	} else {
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		kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
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	}
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	spin_unlock(&root->fs_info->defrag_inodes_lock);
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	return 0;
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}

/*
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 * Requeue the defrag object. If there is a defrag object that points to
 * the same inode in the tree, we will merge them together (by
 * __btrfs_add_inode_defrag()) and free the one that we want to requeue.
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 */
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static void btrfs_requeue_inode_defrag(struct inode *inode,
				       struct inode_defrag *defrag)
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{
	struct btrfs_root *root = BTRFS_I(inode)->root;
	int ret;

	if (!__need_auto_defrag(root))
		goto out;

	/*
	 * Here we don't check the IN_DEFRAG flag, because we need merge
	 * them together.
	 */
	spin_lock(&root->fs_info->defrag_inodes_lock);
	ret = __btrfs_add_inode_defrag(inode, defrag);
	spin_unlock(&root->fs_info->defrag_inodes_lock);
	if (ret)
		goto out;
	return;
out:
	kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
}

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/*
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 * pick the defragable inode that we want, if it doesn't exist, we will get
 * the next one.
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 */
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static struct inode_defrag *
btrfs_pick_defrag_inode(struct btrfs_fs_info *fs_info, u64 root, u64 ino)
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{
	struct inode_defrag *entry = NULL;
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	struct inode_defrag tmp;
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	struct rb_node *p;
	struct rb_node *parent = NULL;
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	int ret;

	tmp.ino = ino;
	tmp.root = root;
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	spin_lock(&fs_info->defrag_inodes_lock);
	p = fs_info->defrag_inodes.rb_node;
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	while (p) {
		parent = p;
		entry = rb_entry(parent, struct inode_defrag, rb_node);

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		ret = __compare_inode_defrag(&tmp, entry);
		if (ret < 0)
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			p = parent->rb_left;
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		else if (ret > 0)
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			p = parent->rb_right;
		else
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			goto out;
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	}

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	if (parent && __compare_inode_defrag(&tmp, entry) > 0) {
		parent = rb_next(parent);
		if (parent)
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			entry = rb_entry(parent, struct inode_defrag, rb_node);
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		else
			entry = NULL;
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	}
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out:
	if (entry)
		rb_erase(parent, &fs_info->defrag_inodes);
	spin_unlock(&fs_info->defrag_inodes_lock);
	return entry;
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}

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void btrfs_cleanup_defrag_inodes(struct btrfs_fs_info *fs_info)
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{
	struct inode_defrag *defrag;
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	struct rb_node *node;

	spin_lock(&fs_info->defrag_inodes_lock);
	node = rb_first(&fs_info->defrag_inodes);
	while (node) {
		rb_erase(node, &fs_info->defrag_inodes);
		defrag = rb_entry(node, struct inode_defrag, rb_node);
		kmem_cache_free(btrfs_inode_defrag_cachep, defrag);

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		cond_resched_lock(&fs_info->defrag_inodes_lock);
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		node = rb_first(&fs_info->defrag_inodes);
	}
	spin_unlock(&fs_info->defrag_inodes_lock);
}

#define BTRFS_DEFRAG_BATCH	1024

static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
				    struct inode_defrag *defrag)
{
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	struct btrfs_root *inode_root;
	struct inode *inode;
	struct btrfs_key key;
	struct btrfs_ioctl_defrag_range_args range;
	int num_defrag;
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	int index;
	int ret;
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	/* get the inode */
	key.objectid = defrag->root;
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	key.type = BTRFS_ROOT_ITEM_KEY;
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	key.offset = (u64)-1;
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	index = srcu_read_lock(&fs_info->subvol_srcu);

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	inode_root = btrfs_read_fs_root_no_name(fs_info, &key);
	if (IS_ERR(inode_root)) {
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		ret = PTR_ERR(inode_root);
		goto cleanup;
	}
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	key.objectid = defrag->ino;
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	key.type = BTRFS_INODE_ITEM_KEY;
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	key.offset = 0;
	inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL);
	if (IS_ERR(inode)) {
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		ret = PTR_ERR(inode);
		goto cleanup;
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	}
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	srcu_read_unlock(&fs_info->subvol_srcu, index);
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	/* do a chunk of defrag */
	clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
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	memset(&range, 0, sizeof(range));
	range.len = (u64)-1;
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	range.start = defrag->last_offset;
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	sb_start_write(fs_info->sb);
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	num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
				       BTRFS_DEFRAG_BATCH);
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	sb_end_write(fs_info->sb);
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	/*
	 * if we filled the whole defrag batch, there
	 * must be more work to do.  Queue this defrag
	 * again
	 */
	if (num_defrag == BTRFS_DEFRAG_BATCH) {
		defrag->last_offset = range.start;
		btrfs_requeue_inode_defrag(inode, defrag);
	} else if (defrag->last_offset && !defrag->cycled) {
		/*
		 * we didn't fill our defrag batch, but
		 * we didn't start at zero.  Make sure we loop
		 * around to the start of the file.
		 */
		defrag->last_offset = 0;
		defrag->cycled = 1;
		btrfs_requeue_inode_defrag(inode, defrag);
	} else {
		kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
	}

	iput(inode);
	return 0;
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cleanup:
	srcu_read_unlock(&fs_info->subvol_srcu, index);
	kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
	return ret;
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}

/*
 * run through the list of inodes in the FS that need
 * defragging
 */
int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
{
	struct inode_defrag *defrag;
	u64 first_ino = 0;
	u64 root_objectid = 0;
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	atomic_inc(&fs_info->defrag_running);
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	while (1) {
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		/* Pause the auto defragger. */
		if (test_bit(BTRFS_FS_STATE_REMOUNTING,
			     &fs_info->fs_state))
			break;

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		if (!__need_auto_defrag(fs_info->tree_root))
			break;
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		/* find an inode to defrag */
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		defrag = btrfs_pick_defrag_inode(fs_info, root_objectid,
						 first_ino);
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		if (!defrag) {
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			if (root_objectid || first_ino) {
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				root_objectid = 0;
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				first_ino = 0;
				continue;
			} else {
				break;
			}
		}

		first_ino = defrag->ino + 1;
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		root_objectid = defrag->root;
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		__btrfs_run_defrag_inode(fs_info, defrag);
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	}
	atomic_dec(&fs_info->defrag_running);

	/*
	 * during unmount, we use the transaction_wait queue to
	 * wait for the defragger to stop
	 */
	wake_up(&fs_info->transaction_wait);
	return 0;
}
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/* simple helper to fault in pages and copy.  This should go away
 * and be replaced with calls into generic code.
 */
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static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
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					 size_t write_bytes,
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					 struct page **prepared_pages,
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					 struct iov_iter *i)
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{
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	size_t copied = 0;
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	size_t total_copied = 0;
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	int pg = 0;
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	int offset = pos & (PAGE_CACHE_SIZE - 1);

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	while (write_bytes > 0) {
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		size_t count = min_t(size_t,
				     PAGE_CACHE_SIZE - offset, write_bytes);
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		struct page *page = prepared_pages[pg];
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		/*
		 * Copy data from userspace to the current page
		 */
		copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
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		/* Flush processor's dcache for this page */
		flush_dcache_page(page);
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		/*
		 * if we get a partial write, we can end up with
		 * partially up to date pages.  These add
		 * a lot of complexity, so make sure they don't
		 * happen by forcing this copy to be retried.
		 *
		 * The rest of the btrfs_file_write code will fall
		 * back to page at a time copies after we return 0.
		 */
		if (!PageUptodate(page) && copied < count)
			copied = 0;

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		iov_iter_advance(i, copied);
		write_bytes -= copied;
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		total_copied += copied;
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		/* Return to btrfs_file_write_iter to fault page */
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		if (unlikely(copied == 0))
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			break;
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		if (copied < PAGE_CACHE_SIZE - offset) {
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			offset += copied;
		} else {
			pg++;
			offset = 0;
		}
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	}
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	return total_copied;
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}

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/*
 * unlocks pages after btrfs_file_write is done with them
 */
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static void btrfs_drop_pages(struct page **pages, size_t num_pages)
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{
	size_t i;
	for (i = 0; i < num_pages; i++) {
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		/* page checked is some magic around finding pages that
		 * have been modified without going through btrfs_set_page_dirty
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		 * clear it here. There should be no need to mark the pages
		 * accessed as prepare_pages should have marked them accessed
		 * in prepare_pages via find_or_create_page()
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		 */
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		ClearPageChecked(pages[i]);
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		unlock_page(pages[i]);
		page_cache_release(pages[i]);
	}
}

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/*
 * after copy_from_user, pages need to be dirtied and we need to make
 * sure holes are created between the current EOF and the start of
 * any next extents (if required).
 *
 * this also makes the decision about creating an inline extent vs
 * doing real data extents, marking pages dirty and delalloc as required.
 */
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int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode,
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			     struct page **pages, size_t num_pages,
			     loff_t pos, size_t write_bytes,
			     struct extent_state **cached)
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{
	int err = 0;
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	int i;
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	u64 num_bytes;
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	u64 start_pos;
	u64 end_of_last_block;
	u64 end_pos = pos + write_bytes;
	loff_t isize = i_size_read(inode);
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	start_pos = pos & ~((u64)root->sectorsize - 1);
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	num_bytes = ALIGN(write_bytes + pos - start_pos, root->sectorsize);
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	end_of_last_block = start_pos + num_bytes - 1;
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	err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
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					cached);
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	if (err)
		return err;
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	for (i = 0; i < num_pages; i++) {
		struct page *p = pages[i];
		SetPageUptodate(p);
		ClearPageChecked(p);
		set_page_dirty(p);
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	}
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	/*
	 * we've only changed i_size in ram, and we haven't updated
	 * the disk i_size.  There is no need to log the inode
	 * at this time.
	 */
	if (end_pos > isize)
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		i_size_write(inode, end_pos);
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	return 0;
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}

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/*
 * this drops all the extents in the cache that intersect the range
 * [start, end].  Existing extents are split as required.
 */
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void btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
			     int skip_pinned)
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{
	struct extent_map *em;
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	struct extent_map *split = NULL;
	struct extent_map *split2 = NULL;
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	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
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	u64 len = end - start + 1;
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	u64 gen;
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	int ret;
	int testend = 1;
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	unsigned long flags;
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	int compressed = 0;
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	bool modified;
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	WARN_ON(end < start);
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	if (end == (u64)-1) {
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		len = (u64)-1;
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		testend = 0;
	}
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	while (1) {
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		int no_splits = 0;

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		modified = false;
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		if (!split)
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			split = alloc_extent_map();
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		if (!split2)
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			split2 = alloc_extent_map();
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		if (!split || !split2)
			no_splits = 1;
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		write_lock(&em_tree->lock);
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		em = lookup_extent_mapping(em_tree, start, len);
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		if (!em) {
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			write_unlock(&em_tree->lock);
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			break;
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		}
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		flags = em->flags;
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		gen = em->generation;
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		if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
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			if (testend && em->start + em->len >= start + len) {
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				free_extent_map(em);
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				write_unlock(&em_tree->lock);
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				break;
			}
576 577
			start = em->start + em->len;
			if (testend)
578 579
				len = start + len - (em->start + em->len);
			free_extent_map(em);
C
Chris Mason 已提交
580
			write_unlock(&em_tree->lock);
581 582
			continue;
		}
C
Chris Mason 已提交
583
		compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
584
		clear_bit(EXTENT_FLAG_PINNED, &em->flags);
L
Liu Bo 已提交
585
		clear_bit(EXTENT_FLAG_LOGGING, &flags);
J
Josef Bacik 已提交
586
		modified = !list_empty(&em->list);
587 588
		if (no_splits)
			goto next;
589

590
		if (em->start < start) {
591 592
			split->start = em->start;
			split->len = start - em->start;
593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612

			if (em->block_start < EXTENT_MAP_LAST_BYTE) {
				split->orig_start = em->orig_start;
				split->block_start = em->block_start;

				if (compressed)
					split->block_len = em->block_len;
				else
					split->block_len = split->len;
				split->orig_block_len = max(split->block_len,
						em->orig_block_len);
				split->ram_bytes = em->ram_bytes;
			} else {
				split->orig_start = split->start;
				split->block_len = 0;
				split->block_start = em->block_start;
				split->orig_block_len = 0;
				split->ram_bytes = split->len;
			}

J
Josef Bacik 已提交
613
			split->generation = gen;
614
			split->bdev = em->bdev;
615
			split->flags = flags;
616
			split->compress_type = em->compress_type;
617
			replace_extent_mapping(em_tree, em, split, modified);
618 619 620 621
			free_extent_map(split);
			split = split2;
			split2 = NULL;
		}
622
		if (testend && em->start + em->len > start + len) {
623 624 625 626 627
			u64 diff = start + len - em->start;

			split->start = start + len;
			split->len = em->start + em->len - (start + len);
			split->bdev = em->bdev;
628
			split->flags = flags;
629
			split->compress_type = em->compress_type;
J
Josef Bacik 已提交
630
			split->generation = gen;
631 632 633

			if (em->block_start < EXTENT_MAP_LAST_BYTE) {
				split->orig_block_len = max(em->block_len,
634
						    em->orig_block_len);
635

636 637 638 639 640 641 642 643 644 645 646
				split->ram_bytes = em->ram_bytes;
				if (compressed) {
					split->block_len = em->block_len;
					split->block_start = em->block_start;
					split->orig_start = em->orig_start;
				} else {
					split->block_len = split->len;
					split->block_start = em->block_start
						+ diff;
					split->orig_start = em->orig_start;
				}
C
Chris Mason 已提交
647
			} else {
648 649 650 651 652
				split->ram_bytes = split->len;
				split->orig_start = split->start;
				split->block_len = 0;
				split->block_start = em->block_start;
				split->orig_block_len = 0;
C
Chris Mason 已提交
653
			}
654

655 656 657 658 659 660 661 662
			if (extent_map_in_tree(em)) {
				replace_extent_mapping(em_tree, em, split,
						       modified);
			} else {
				ret = add_extent_mapping(em_tree, split,
							 modified);
				ASSERT(ret == 0); /* Logic error */
			}
663 664 665
			free_extent_map(split);
			split = NULL;
		}
666
next:
667 668
		if (extent_map_in_tree(em))
			remove_extent_mapping(em_tree, em);
669
		write_unlock(&em_tree->lock);
670

671 672 673 674 675
		/* once for us */
		free_extent_map(em);
		/* once for the tree*/
		free_extent_map(em);
	}
676 677 678 679
	if (split)
		free_extent_map(split);
	if (split2)
		free_extent_map(split2);
680 681
}

C
Chris Mason 已提交
682 683 684 685 686 687 688 689 690
/*
 * this is very complex, but the basic idea is to drop all extents
 * in the range start - end.  hint_block is filled in with a block number
 * that would be a good hint to the block allocator for this file.
 *
 * If an extent intersects the range but is not entirely inside the range
 * it is either truncated or split.  Anything entirely inside the range
 * is deleted from the tree.
 */
J
Josef Bacik 已提交
691 692 693
int __btrfs_drop_extents(struct btrfs_trans_handle *trans,
			 struct btrfs_root *root, struct inode *inode,
			 struct btrfs_path *path, u64 start, u64 end,
694 695 696 697
			 u64 *drop_end, int drop_cache,
			 int replace_extent,
			 u32 extent_item_size,
			 int *key_inserted)
C
Chris Mason 已提交
698
{
699
	struct extent_buffer *leaf;
Y
Yan, Zheng 已提交
700
	struct btrfs_file_extent_item *fi;
701
	struct btrfs_key key;
Y
Yan, Zheng 已提交
702
	struct btrfs_key new_key;
L
Li Zefan 已提交
703
	u64 ino = btrfs_ino(inode);
Y
Yan, Zheng 已提交
704 705 706 707 708 709 710 711
	u64 search_start = start;
	u64 disk_bytenr = 0;
	u64 num_bytes = 0;
	u64 extent_offset = 0;
	u64 extent_end = 0;
	int del_nr = 0;
	int del_slot = 0;
	int extent_type;
C
Chris Mason 已提交
712
	int recow;
713
	int ret;
714
	int modify_tree = -1;
715
	int update_refs;
716
	int found = 0;
717
	int leafs_visited = 0;
C
Chris Mason 已提交
718

C
Chris Mason 已提交
719 720
	if (drop_cache)
		btrfs_drop_extent_cache(inode, start, end - 1, 0);
721

722
	if (start >= BTRFS_I(inode)->disk_i_size && !replace_extent)
723 724
		modify_tree = 0;

725 726
	update_refs = (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
		       root == root->fs_info->tree_root);
C
Chris Mason 已提交
727
	while (1) {
C
Chris Mason 已提交
728
		recow = 0;
L
Li Zefan 已提交
729
		ret = btrfs_lookup_file_extent(trans, root, path, ino,
730
					       search_start, modify_tree);
C
Chris Mason 已提交
731
		if (ret < 0)
Y
Yan, Zheng 已提交
732 733 734 735
			break;
		if (ret > 0 && path->slots[0] > 0 && search_start == start) {
			leaf = path->nodes[0];
			btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
L
Li Zefan 已提交
736
			if (key.objectid == ino &&
Y
Yan, Zheng 已提交
737 738
			    key.type == BTRFS_EXTENT_DATA_KEY)
				path->slots[0]--;
C
Chris Mason 已提交
739
		}
Y
Yan, Zheng 已提交
740
		ret = 0;
741
		leafs_visited++;
742
next_slot:
743
		leaf = path->nodes[0];
Y
Yan, Zheng 已提交
744 745 746 747 748 749 750 751
		if (path->slots[0] >= btrfs_header_nritems(leaf)) {
			BUG_ON(del_nr > 0);
			ret = btrfs_next_leaf(root, path);
			if (ret < 0)
				break;
			if (ret > 0) {
				ret = 0;
				break;
752
			}
753
			leafs_visited++;
Y
Yan, Zheng 已提交
754 755 756 757 758
			leaf = path->nodes[0];
			recow = 1;
		}

		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
759 760 761 762 763 764 765 766 767 768

		if (key.objectid > ino)
			break;
		if (WARN_ON_ONCE(key.objectid < ino) ||
		    key.type < BTRFS_EXTENT_DATA_KEY) {
			ASSERT(del_nr == 0);
			path->slots[0]++;
			goto next_slot;
		}
		if (key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
Y
Yan, Zheng 已提交
769 770 771 772 773 774 775 776 777 778 779 780 781 782 783
			break;

		fi = btrfs_item_ptr(leaf, path->slots[0],
				    struct btrfs_file_extent_item);
		extent_type = btrfs_file_extent_type(leaf, fi);

		if (extent_type == BTRFS_FILE_EXTENT_REG ||
		    extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
			disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
			num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
			extent_offset = btrfs_file_extent_offset(leaf, fi);
			extent_end = key.offset +
				btrfs_file_extent_num_bytes(leaf, fi);
		} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
			extent_end = key.offset +
784 785
				btrfs_file_extent_inline_len(leaf,
						     path->slots[0], fi);
786
		} else {
787 788
			/* can't happen */
			BUG();
C
Chris Mason 已提交
789 790
		}

791 792 793 794 795 796 797 798 799 800 801 802
		/*
		 * Don't skip extent items representing 0 byte lengths. They
		 * used to be created (bug) if while punching holes we hit
		 * -ENOSPC condition. So if we find one here, just ensure we
		 * delete it, otherwise we would insert a new file extent item
		 * with the same key (offset) as that 0 bytes length file
		 * extent item in the call to setup_items_for_insert() later
		 * in this function.
		 */
		if (extent_end == key.offset && extent_end >= search_start)
			goto delete_extent_item;

Y
Yan, Zheng 已提交
803 804
		if (extent_end <= search_start) {
			path->slots[0]++;
805
			goto next_slot;
C
Chris Mason 已提交
806 807
		}

808
		found = 1;
Y
Yan, Zheng 已提交
809
		search_start = max(key.offset, start);
810 811
		if (recow || !modify_tree) {
			modify_tree = -1;
812
			btrfs_release_path(path);
Y
Yan, Zheng 已提交
813
			continue;
C
Chris Mason 已提交
814
		}
Y
Yan Zheng 已提交
815

Y
Yan, Zheng 已提交
816 817 818 819 820 821
		/*
		 *     | - range to drop - |
		 *  | -------- extent -------- |
		 */
		if (start > key.offset && end < extent_end) {
			BUG_ON(del_nr > 0);
822
			if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
823
				ret = -EOPNOTSUPP;
824 825
				break;
			}
Y
Yan, Zheng 已提交
826 827 828 829 830 831

			memcpy(&new_key, &key, sizeof(new_key));
			new_key.offset = start;
			ret = btrfs_duplicate_item(trans, root, path,
						   &new_key);
			if (ret == -EAGAIN) {
832
				btrfs_release_path(path);
Y
Yan, Zheng 已提交
833
				continue;
Y
Yan Zheng 已提交
834
			}
Y
Yan, Zheng 已提交
835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852
			if (ret < 0)
				break;

			leaf = path->nodes[0];
			fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
					    struct btrfs_file_extent_item);
			btrfs_set_file_extent_num_bytes(leaf, fi,
							start - key.offset);

			fi = btrfs_item_ptr(leaf, path->slots[0],
					    struct btrfs_file_extent_item);

			extent_offset += start - key.offset;
			btrfs_set_file_extent_offset(leaf, fi, extent_offset);
			btrfs_set_file_extent_num_bytes(leaf, fi,
							extent_end - start);
			btrfs_mark_buffer_dirty(leaf);

J
Josef Bacik 已提交
853
			if (update_refs && disk_bytenr > 0) {
854
				ret = btrfs_inc_extent_ref(trans, root,
Y
Yan, Zheng 已提交
855 856 857
						disk_bytenr, num_bytes, 0,
						root->root_key.objectid,
						new_key.objectid,
858
						start - extent_offset);
859
				BUG_ON(ret); /* -ENOMEM */
860
			}
Y
Yan, Zheng 已提交
861
			key.offset = start;
Y
Yan Zheng 已提交
862
		}
Y
Yan, Zheng 已提交
863 864 865 866 867
		/*
		 *  | ---- range to drop ----- |
		 *      | -------- extent -------- |
		 */
		if (start <= key.offset && end < extent_end) {
868
			if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
869
				ret = -EOPNOTSUPP;
870 871
				break;
			}
Y
Yan Zheng 已提交
872

Y
Yan, Zheng 已提交
873 874
			memcpy(&new_key, &key, sizeof(new_key));
			new_key.offset = end;
875
			btrfs_set_item_key_safe(root->fs_info, path, &new_key);
Y
Yan Zheng 已提交
876

Y
Yan, Zheng 已提交
877 878 879 880 881
			extent_offset += end - key.offset;
			btrfs_set_file_extent_offset(leaf, fi, extent_offset);
			btrfs_set_file_extent_num_bytes(leaf, fi,
							extent_end - end);
			btrfs_mark_buffer_dirty(leaf);
882
			if (update_refs && disk_bytenr > 0)
Y
Yan, Zheng 已提交
883 884
				inode_sub_bytes(inode, end - key.offset);
			break;
C
Chris Mason 已提交
885
		}
886

Y
Yan, Zheng 已提交
887 888 889 890 891 892 893
		search_start = extent_end;
		/*
		 *       | ---- range to drop ----- |
		 *  | -------- extent -------- |
		 */
		if (start > key.offset && end >= extent_end) {
			BUG_ON(del_nr > 0);
894
			if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
895
				ret = -EOPNOTSUPP;
896 897
				break;
			}
898

Y
Yan, Zheng 已提交
899 900 901
			btrfs_set_file_extent_num_bytes(leaf, fi,
							start - key.offset);
			btrfs_mark_buffer_dirty(leaf);
902
			if (update_refs && disk_bytenr > 0)
Y
Yan, Zheng 已提交
903 904 905
				inode_sub_bytes(inode, extent_end - start);
			if (end == extent_end)
				break;
C
Chris Mason 已提交
906

Y
Yan, Zheng 已提交
907 908
			path->slots[0]++;
			goto next_slot;
Z
Zheng Yan 已提交
909 910
		}

Y
Yan, Zheng 已提交
911 912 913 914 915
		/*
		 *  | ---- range to drop ----- |
		 *    | ------ extent ------ |
		 */
		if (start <= key.offset && end >= extent_end) {
916
delete_extent_item:
Y
Yan, Zheng 已提交
917 918 919 920 921 922 923
			if (del_nr == 0) {
				del_slot = path->slots[0];
				del_nr = 1;
			} else {
				BUG_ON(del_slot + del_nr != path->slots[0]);
				del_nr++;
			}
Z
Zheng Yan 已提交
924

J
Josef Bacik 已提交
925 926
			if (update_refs &&
			    extent_type == BTRFS_FILE_EXTENT_INLINE) {
927
				inode_sub_bytes(inode,
Y
Yan, Zheng 已提交
928 929 930
						extent_end - key.offset);
				extent_end = ALIGN(extent_end,
						   root->sectorsize);
J
Josef Bacik 已提交
931
			} else if (update_refs && disk_bytenr > 0) {
Z
Zheng Yan 已提交
932
				ret = btrfs_free_extent(trans, root,
Y
Yan, Zheng 已提交
933 934
						disk_bytenr, num_bytes, 0,
						root->root_key.objectid,
935
						key.objectid, key.offset -
936
						extent_offset);
937
				BUG_ON(ret); /* -ENOMEM */
Y
Yan, Zheng 已提交
938 939
				inode_sub_bytes(inode,
						extent_end - key.offset);
Z
Zheng Yan 已提交
940 941
			}

Y
Yan, Zheng 已提交
942 943 944 945 946 947 948 949 950 951
			if (end == extent_end)
				break;

			if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
				path->slots[0]++;
				goto next_slot;
			}

			ret = btrfs_del_items(trans, root, path, del_slot,
					      del_nr);
952 953
			if (ret) {
				btrfs_abort_transaction(trans, root, ret);
J
Josef Bacik 已提交
954
				break;
955
			}
Y
Yan, Zheng 已提交
956 957 958 959

			del_nr = 0;
			del_slot = 0;

960
			btrfs_release_path(path);
Y
Yan, Zheng 已提交
961
			continue;
C
Chris Mason 已提交
962
		}
Y
Yan, Zheng 已提交
963 964

		BUG_ON(1);
C
Chris Mason 已提交
965
	}
Y
Yan, Zheng 已提交
966

967
	if (!ret && del_nr > 0) {
968 969 970 971
		/*
		 * Set path->slots[0] to first slot, so that after the delete
		 * if items are move off from our leaf to its immediate left or
		 * right neighbor leafs, we end up with a correct and adjusted
972
		 * path->slots[0] for our insertion (if replace_extent != 0).
973 974
		 */
		path->slots[0] = del_slot;
Y
Yan, Zheng 已提交
975
		ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
976 977
		if (ret)
			btrfs_abort_transaction(trans, root, ret);
978
	}
979

980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000
	leaf = path->nodes[0];
	/*
	 * If btrfs_del_items() was called, it might have deleted a leaf, in
	 * which case it unlocked our path, so check path->locks[0] matches a
	 * write lock.
	 */
	if (!ret && replace_extent && leafs_visited == 1 &&
	    (path->locks[0] == BTRFS_WRITE_LOCK_BLOCKING ||
	     path->locks[0] == BTRFS_WRITE_LOCK) &&
	    btrfs_leaf_free_space(root, leaf) >=
	    sizeof(struct btrfs_item) + extent_item_size) {

		key.objectid = ino;
		key.type = BTRFS_EXTENT_DATA_KEY;
		key.offset = start;
		if (!del_nr && path->slots[0] < btrfs_header_nritems(leaf)) {
			struct btrfs_key slot_key;

			btrfs_item_key_to_cpu(leaf, &slot_key, path->slots[0]);
			if (btrfs_comp_cpu_keys(&key, &slot_key) > 0)
				path->slots[0]++;
1001
		}
1002 1003 1004 1005 1006 1007
		setup_items_for_insert(root, path, &key,
				       &extent_item_size,
				       extent_item_size,
				       sizeof(struct btrfs_item) +
				       extent_item_size, 1);
		*key_inserted = 1;
Y
Yan Zheng 已提交
1008
	}
Y
Yan, Zheng 已提交
1009

1010 1011
	if (!replace_extent || !(*key_inserted))
		btrfs_release_path(path);
J
Josef Bacik 已提交
1012
	if (drop_end)
1013
		*drop_end = found ? min(end, extent_end) : end;
J
Josef Bacik 已提交
1014 1015 1016 1017 1018
	return ret;
}

int btrfs_drop_extents(struct btrfs_trans_handle *trans,
		       struct btrfs_root *root, struct inode *inode, u64 start,
1019
		       u64 end, int drop_cache)
J
Josef Bacik 已提交
1020 1021 1022 1023 1024 1025 1026
{
	struct btrfs_path *path;
	int ret;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;
J
Josef Bacik 已提交
1027
	ret = __btrfs_drop_extents(trans, root, inode, path, start, end, NULL,
1028
				   drop_cache, 0, 0, NULL);
Y
Yan, Zheng 已提交
1029
	btrfs_free_path(path);
C
Chris Mason 已提交
1030 1031 1032
	return ret;
}

Y
Yan Zheng 已提交
1033
static int extent_mergeable(struct extent_buffer *leaf, int slot,
1034 1035
			    u64 objectid, u64 bytenr, u64 orig_offset,
			    u64 *start, u64 *end)
Y
Yan Zheng 已提交
1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050
{
	struct btrfs_file_extent_item *fi;
	struct btrfs_key key;
	u64 extent_end;

	if (slot < 0 || slot >= btrfs_header_nritems(leaf))
		return 0;

	btrfs_item_key_to_cpu(leaf, &key, slot);
	if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
		return 0;

	fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
	if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
	    btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
1051
	    btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
Y
Yan Zheng 已提交
1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075
	    btrfs_file_extent_compression(leaf, fi) ||
	    btrfs_file_extent_encryption(leaf, fi) ||
	    btrfs_file_extent_other_encoding(leaf, fi))
		return 0;

	extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
	if ((*start && *start != key.offset) || (*end && *end != extent_end))
		return 0;

	*start = key.offset;
	*end = extent_end;
	return 1;
}

/*
 * Mark extent in the range start - end as written.
 *
 * This changes extent type from 'pre-allocated' to 'regular'. If only
 * part of extent is marked as written, the extent will be split into
 * two or three.
 */
int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
			      struct inode *inode, u64 start, u64 end)
{
Y
Yan, Zheng 已提交
1076
	struct btrfs_root *root = BTRFS_I(inode)->root;
Y
Yan Zheng 已提交
1077 1078 1079 1080
	struct extent_buffer *leaf;
	struct btrfs_path *path;
	struct btrfs_file_extent_item *fi;
	struct btrfs_key key;
Y
Yan, Zheng 已提交
1081
	struct btrfs_key new_key;
Y
Yan Zheng 已提交
1082 1083 1084
	u64 bytenr;
	u64 num_bytes;
	u64 extent_end;
1085
	u64 orig_offset;
Y
Yan Zheng 已提交
1086 1087
	u64 other_start;
	u64 other_end;
Y
Yan, Zheng 已提交
1088 1089 1090
	u64 split;
	int del_nr = 0;
	int del_slot = 0;
1091
	int recow;
Y
Yan Zheng 已提交
1092
	int ret;
L
Li Zefan 已提交
1093
	u64 ino = btrfs_ino(inode);
Y
Yan Zheng 已提交
1094 1095

	path = btrfs_alloc_path();
1096 1097
	if (!path)
		return -ENOMEM;
Y
Yan Zheng 已提交
1098
again:
1099
	recow = 0;
Y
Yan, Zheng 已提交
1100
	split = start;
L
Li Zefan 已提交
1101
	key.objectid = ino;
Y
Yan Zheng 已提交
1102
	key.type = BTRFS_EXTENT_DATA_KEY;
Y
Yan, Zheng 已提交
1103
	key.offset = split;
Y
Yan Zheng 已提交
1104 1105

	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1106 1107
	if (ret < 0)
		goto out;
Y
Yan Zheng 已提交
1108 1109 1110 1111 1112
	if (ret > 0 && path->slots[0] > 0)
		path->slots[0]--;

	leaf = path->nodes[0];
	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
L
Li Zefan 已提交
1113
	BUG_ON(key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY);
Y
Yan Zheng 已提交
1114 1115
	fi = btrfs_item_ptr(leaf, path->slots[0],
			    struct btrfs_file_extent_item);
Y
Yan, Zheng 已提交
1116 1117
	BUG_ON(btrfs_file_extent_type(leaf, fi) !=
	       BTRFS_FILE_EXTENT_PREALLOC);
Y
Yan Zheng 已提交
1118 1119 1120 1121 1122
	extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
	BUG_ON(key.offset > start || extent_end < end);

	bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
	num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1123
	orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
1124 1125 1126 1127 1128 1129
	memcpy(&new_key, &key, sizeof(new_key));

	if (start == key.offset && end < extent_end) {
		other_start = 0;
		other_end = start;
		if (extent_mergeable(leaf, path->slots[0] - 1,
L
Li Zefan 已提交
1130
				     ino, bytenr, orig_offset,
1131 1132
				     &other_start, &other_end)) {
			new_key.offset = end;
1133
			btrfs_set_item_key_safe(root->fs_info, path, &new_key);
1134 1135
			fi = btrfs_item_ptr(leaf, path->slots[0],
					    struct btrfs_file_extent_item);
1136 1137
			btrfs_set_file_extent_generation(leaf, fi,
							 trans->transid);
1138 1139 1140 1141 1142 1143
			btrfs_set_file_extent_num_bytes(leaf, fi,
							extent_end - end);
			btrfs_set_file_extent_offset(leaf, fi,
						     end - orig_offset);
			fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
					    struct btrfs_file_extent_item);
1144 1145
			btrfs_set_file_extent_generation(leaf, fi,
							 trans->transid);
1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156
			btrfs_set_file_extent_num_bytes(leaf, fi,
							end - other_start);
			btrfs_mark_buffer_dirty(leaf);
			goto out;
		}
	}

	if (start > key.offset && end == extent_end) {
		other_start = end;
		other_end = 0;
		if (extent_mergeable(leaf, path->slots[0] + 1,
L
Li Zefan 已提交
1157
				     ino, bytenr, orig_offset,
1158 1159 1160 1161 1162
				     &other_start, &other_end)) {
			fi = btrfs_item_ptr(leaf, path->slots[0],
					    struct btrfs_file_extent_item);
			btrfs_set_file_extent_num_bytes(leaf, fi,
							start - key.offset);
1163 1164
			btrfs_set_file_extent_generation(leaf, fi,
							 trans->transid);
1165 1166
			path->slots[0]++;
			new_key.offset = start;
1167
			btrfs_set_item_key_safe(root->fs_info, path, &new_key);
1168 1169 1170

			fi = btrfs_item_ptr(leaf, path->slots[0],
					    struct btrfs_file_extent_item);
1171 1172
			btrfs_set_file_extent_generation(leaf, fi,
							 trans->transid);
1173 1174 1175 1176 1177 1178 1179 1180
			btrfs_set_file_extent_num_bytes(leaf, fi,
							other_end - start);
			btrfs_set_file_extent_offset(leaf, fi,
						     start - orig_offset);
			btrfs_mark_buffer_dirty(leaf);
			goto out;
		}
	}
Y
Yan Zheng 已提交
1181

Y
Yan, Zheng 已提交
1182 1183 1184 1185 1186 1187 1188
	while (start > key.offset || end < extent_end) {
		if (key.offset == start)
			split = end;

		new_key.offset = split;
		ret = btrfs_duplicate_item(trans, root, path, &new_key);
		if (ret == -EAGAIN) {
1189
			btrfs_release_path(path);
Y
Yan, Zheng 已提交
1190
			goto again;
Y
Yan Zheng 已提交
1191
		}
1192 1193 1194 1195
		if (ret < 0) {
			btrfs_abort_transaction(trans, root, ret);
			goto out;
		}
Y
Yan Zheng 已提交
1196

Y
Yan, Zheng 已提交
1197 1198
		leaf = path->nodes[0];
		fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
Y
Yan Zheng 已提交
1199
				    struct btrfs_file_extent_item);
1200
		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
Y
Yan Zheng 已提交
1201
		btrfs_set_file_extent_num_bytes(leaf, fi,
Y
Yan, Zheng 已提交
1202 1203 1204 1205 1206
						split - key.offset);

		fi = btrfs_item_ptr(leaf, path->slots[0],
				    struct btrfs_file_extent_item);

1207
		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
Y
Yan, Zheng 已提交
1208 1209 1210
		btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
		btrfs_set_file_extent_num_bytes(leaf, fi,
						extent_end - split);
Y
Yan Zheng 已提交
1211 1212
		btrfs_mark_buffer_dirty(leaf);

Y
Yan, Zheng 已提交
1213 1214
		ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
					   root->root_key.objectid,
1215
					   ino, orig_offset);
1216
		BUG_ON(ret); /* -ENOMEM */
Y
Yan Zheng 已提交
1217

Y
Yan, Zheng 已提交
1218 1219 1220 1221
		if (split == start) {
			key.offset = start;
		} else {
			BUG_ON(start != key.offset);
Y
Yan Zheng 已提交
1222
			path->slots[0]--;
Y
Yan, Zheng 已提交
1223
			extent_end = end;
Y
Yan Zheng 已提交
1224
		}
1225
		recow = 1;
Y
Yan Zheng 已提交
1226 1227
	}

Y
Yan, Zheng 已提交
1228 1229
	other_start = end;
	other_end = 0;
1230
	if (extent_mergeable(leaf, path->slots[0] + 1,
L
Li Zefan 已提交
1231
			     ino, bytenr, orig_offset,
1232 1233
			     &other_start, &other_end)) {
		if (recow) {
1234
			btrfs_release_path(path);
1235 1236
			goto again;
		}
Y
Yan, Zheng 已提交
1237 1238 1239 1240 1241
		extent_end = other_end;
		del_slot = path->slots[0] + 1;
		del_nr++;
		ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
					0, root->root_key.objectid,
1242
					ino, orig_offset);
1243
		BUG_ON(ret); /* -ENOMEM */
Y
Yan Zheng 已提交
1244
	}
Y
Yan, Zheng 已提交
1245 1246
	other_start = 0;
	other_end = start;
1247
	if (extent_mergeable(leaf, path->slots[0] - 1,
L
Li Zefan 已提交
1248
			     ino, bytenr, orig_offset,
1249 1250
			     &other_start, &other_end)) {
		if (recow) {
1251
			btrfs_release_path(path);
1252 1253
			goto again;
		}
Y
Yan, Zheng 已提交
1254 1255 1256 1257 1258
		key.offset = other_start;
		del_slot = path->slots[0];
		del_nr++;
		ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
					0, root->root_key.objectid,
1259
					ino, orig_offset);
1260
		BUG_ON(ret); /* -ENOMEM */
Y
Yan, Zheng 已提交
1261 1262
	}
	if (del_nr == 0) {
1263 1264
		fi = btrfs_item_ptr(leaf, path->slots[0],
			   struct btrfs_file_extent_item);
Y
Yan, Zheng 已提交
1265 1266
		btrfs_set_file_extent_type(leaf, fi,
					   BTRFS_FILE_EXTENT_REG);
1267
		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
Y
Yan, Zheng 已提交
1268
		btrfs_mark_buffer_dirty(leaf);
1269
	} else {
1270 1271
		fi = btrfs_item_ptr(leaf, del_slot - 1,
			   struct btrfs_file_extent_item);
1272 1273
		btrfs_set_file_extent_type(leaf, fi,
					   BTRFS_FILE_EXTENT_REG);
1274
		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1275 1276 1277
		btrfs_set_file_extent_num_bytes(leaf, fi,
						extent_end - key.offset);
		btrfs_mark_buffer_dirty(leaf);
Y
Yan, Zheng 已提交
1278

1279
		ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
1280 1281 1282 1283
		if (ret < 0) {
			btrfs_abort_transaction(trans, root, ret);
			goto out;
		}
1284
	}
Y
Yan, Zheng 已提交
1285
out:
Y
Yan Zheng 已提交
1286 1287 1288 1289
	btrfs_free_path(path);
	return 0;
}

1290 1291 1292 1293
/*
 * on error we return an unlocked page and the error value
 * on success we return a locked page and 0
 */
1294 1295
static int prepare_uptodate_page(struct page *page, u64 pos,
				 bool force_uptodate)
1296 1297 1298
{
	int ret = 0;

1299 1300
	if (((pos & (PAGE_CACHE_SIZE - 1)) || force_uptodate) &&
	    !PageUptodate(page)) {
1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312
		ret = btrfs_readpage(NULL, page);
		if (ret)
			return ret;
		lock_page(page);
		if (!PageUptodate(page)) {
			unlock_page(page);
			return -EIO;
		}
	}
	return 0;
}

C
Chris Mason 已提交
1313
/*
1314
 * this just gets pages into the page cache and locks them down.
C
Chris Mason 已提交
1315
 */
1316 1317 1318
static noinline int prepare_pages(struct inode *inode, struct page **pages,
				  size_t num_pages, loff_t pos,
				  size_t write_bytes, bool force_uptodate)
C
Chris Mason 已提交
1319 1320 1321
{
	int i;
	unsigned long index = pos >> PAGE_CACHE_SHIFT;
1322
	gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1323
	int err = 0;
1324
	int faili;
1325

C
Chris Mason 已提交
1326
	for (i = 0; i < num_pages; i++) {
1327
		pages[i] = find_or_create_page(inode->i_mapping, index + i,
1328
					       mask | __GFP_WRITE);
C
Chris Mason 已提交
1329
		if (!pages[i]) {
1330 1331 1332 1333 1334 1335
			faili = i - 1;
			err = -ENOMEM;
			goto fail;
		}

		if (i == 0)
1336 1337
			err = prepare_uptodate_page(pages[i], pos,
						    force_uptodate);
1338 1339
		if (i == num_pages - 1)
			err = prepare_uptodate_page(pages[i],
1340
						    pos + write_bytes, false);
1341 1342 1343 1344
		if (err) {
			page_cache_release(pages[i]);
			faili = i - 1;
			goto fail;
C
Chris Mason 已提交
1345
		}
C
Chris Mason 已提交
1346
		wait_on_page_writeback(pages[i]);
C
Chris Mason 已提交
1347
	}
1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383

	return 0;
fail:
	while (faili >= 0) {
		unlock_page(pages[faili]);
		page_cache_release(pages[faili]);
		faili--;
	}
	return err;

}

/*
 * This function locks the extent and properly waits for data=ordered extents
 * to finish before allowing the pages to be modified if need.
 *
 * The return value:
 * 1 - the extent is locked
 * 0 - the extent is not locked, and everything is OK
 * -EAGAIN - need re-prepare the pages
 * the other < 0 number - Something wrong happens
 */
static noinline int
lock_and_cleanup_extent_if_need(struct inode *inode, struct page **pages,
				size_t num_pages, loff_t pos,
				u64 *lockstart, u64 *lockend,
				struct extent_state **cached_state)
{
	u64 start_pos;
	u64 last_pos;
	int i;
	int ret = 0;

	start_pos = pos & ~((u64)PAGE_CACHE_SIZE - 1);
	last_pos = start_pos + ((u64)num_pages << PAGE_CACHE_SHIFT) - 1;

1384
	if (start_pos < inode->i_size) {
1385
		struct btrfs_ordered_extent *ordered;
1386
		lock_extent_bits(&BTRFS_I(inode)->io_tree,
1387
				 start_pos, last_pos, 0, cached_state);
1388 1389
		ordered = btrfs_lookup_ordered_range(inode, start_pos,
						     last_pos - start_pos + 1);
1390 1391
		if (ordered &&
		    ordered->file_offset + ordered->len > start_pos &&
1392
		    ordered->file_offset <= last_pos) {
1393
			unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1394 1395
					     start_pos, last_pos,
					     cached_state, GFP_NOFS);
1396 1397 1398 1399
			for (i = 0; i < num_pages; i++) {
				unlock_page(pages[i]);
				page_cache_release(pages[i]);
			}
1400 1401 1402
			btrfs_start_ordered_extent(inode, ordered, 1);
			btrfs_put_ordered_extent(ordered);
			return -EAGAIN;
1403 1404 1405 1406
		}
		if (ordered)
			btrfs_put_ordered_extent(ordered);

1407
		clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
1408
				  last_pos, EXTENT_DIRTY | EXTENT_DELALLOC |
1409
				  EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
1410 1411 1412 1413
				  0, 0, cached_state, GFP_NOFS);
		*lockstart = start_pos;
		*lockend = last_pos;
		ret = 1;
1414
	}
1415

1416
	for (i = 0; i < num_pages; i++) {
1417 1418
		if (clear_page_dirty_for_io(pages[i]))
			account_page_redirty(pages[i]);
1419 1420 1421
		set_page_extent_mapped(pages[i]);
		WARN_ON(!PageLocked(pages[i]));
	}
1422

1423
	return ret;
C
Chris Mason 已提交
1424 1425
}

1426 1427 1428 1429 1430 1431 1432 1433 1434
static noinline int check_can_nocow(struct inode *inode, loff_t pos,
				    size_t *write_bytes)
{
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct btrfs_ordered_extent *ordered;
	u64 lockstart, lockend;
	u64 num_bytes;
	int ret;

1435
	ret = btrfs_start_write_no_snapshoting(root);
1436 1437 1438
	if (!ret)
		return -ENOSPC;

1439
	lockstart = round_down(pos, root->sectorsize);
1440
	lockend = round_up(pos + *write_bytes, root->sectorsize) - 1;
1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454

	while (1) {
		lock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
		ordered = btrfs_lookup_ordered_range(inode, lockstart,
						     lockend - lockstart + 1);
		if (!ordered) {
			break;
		}
		unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
		btrfs_start_ordered_extent(inode, ordered, 1);
		btrfs_put_ordered_extent(ordered);
	}

	num_bytes = lockend - lockstart + 1;
1455
	ret = can_nocow_extent(inode, lockstart, &num_bytes, NULL, NULL, NULL);
1456 1457
	if (ret <= 0) {
		ret = 0;
1458
		btrfs_end_write_no_snapshoting(root);
1459
	} else {
1460 1461
		*write_bytes = min_t(size_t, *write_bytes ,
				     num_bytes - pos + lockstart);
1462 1463 1464 1465 1466 1467 1468
	}

	unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);

	return ret;
}

J
Josef Bacik 已提交
1469 1470 1471
static noinline ssize_t __btrfs_buffered_write(struct file *file,
					       struct iov_iter *i,
					       loff_t pos)
1472
{
A
Al Viro 已提交
1473
	struct inode *inode = file_inode(file);
1474 1475
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct page **pages = NULL;
1476
	struct extent_state *cached_state = NULL;
1477
	u64 release_bytes = 0;
1478 1479
	u64 lockstart;
	u64 lockend;
J
Josef Bacik 已提交
1480 1481
	size_t num_written = 0;
	int nrptrs;
1482
	int ret = 0;
1483
	bool only_release_metadata = false;
1484
	bool force_page_uptodate = false;
1485
	bool need_unlock;
1486

1487 1488
	nrptrs = min(DIV_ROUND_UP(iov_iter_count(i), PAGE_CACHE_SIZE),
			PAGE_CACHE_SIZE / (sizeof(struct page *)));
1489 1490
	nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
	nrptrs = max(nrptrs, 8);
1491
	pages = kmalloc_array(nrptrs, sizeof(struct page *), GFP_KERNEL);
J
Josef Bacik 已提交
1492 1493
	if (!pages)
		return -ENOMEM;
1494

J
Josef Bacik 已提交
1495
	while (iov_iter_count(i) > 0) {
C
Chris Mason 已提交
1496
		size_t offset = pos & (PAGE_CACHE_SIZE - 1);
J
Josef Bacik 已提交
1497
		size_t write_bytes = min(iov_iter_count(i),
1498
					 nrptrs * (size_t)PAGE_CACHE_SIZE -
1499
					 offset);
1500 1501
		size_t num_pages = DIV_ROUND_UP(write_bytes + offset,
						PAGE_CACHE_SIZE);
1502
		size_t reserve_bytes;
J
Josef Bacik 已提交
1503 1504
		size_t dirty_pages;
		size_t copied;
C
Chris Mason 已提交
1505

1506
		WARN_ON(num_pages > nrptrs);
1507

1508 1509 1510 1511
		/*
		 * Fault pages before locking them in prepare_pages
		 * to avoid recursive lock
		 */
J
Josef Bacik 已提交
1512
		if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
1513
			ret = -EFAULT;
J
Josef Bacik 已提交
1514
			break;
1515 1516
		}

1517
		reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
1518 1519 1520

		if (BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW |
					     BTRFS_INODE_PREALLOC)) {
1521
			ret = check_can_nocow(inode, pos, &write_bytes);
1522 1523
			if (ret < 0)
				break;
1524
			if (ret > 0) {
1525 1526 1527 1528
				/*
				 * For nodata cow case, no need to reserve
				 * data space.
				 */
1529 1530 1531 1532 1533
				only_release_metadata = true;
				/*
				 * our prealloc extent may be smaller than
				 * write_bytes, so scale down.
				 */
1534 1535
				num_pages = DIV_ROUND_UP(write_bytes + offset,
							 PAGE_CACHE_SIZE);
1536
				reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
1537
				goto reserve_metadata;
1538 1539
			}
		}
1540
		ret = btrfs_check_data_free_space(inode, pos, write_bytes);
1541
		if (ret < 0)
J
Josef Bacik 已提交
1542
			break;
1543

1544
reserve_metadata:
1545 1546 1547
		ret = btrfs_delalloc_reserve_metadata(inode, reserve_bytes);
		if (ret) {
			if (!only_release_metadata)
1548 1549
				btrfs_free_reserved_data_space(inode, pos,
							       write_bytes);
1550
			else
1551
				btrfs_end_write_no_snapshoting(root);
1552 1553 1554 1555
			break;
		}

		release_bytes = reserve_bytes;
1556 1557
		need_unlock = false;
again:
1558 1559 1560 1561 1562
		/*
		 * This is going to setup the pages array with the number of
		 * pages we want, so we don't really need to worry about the
		 * contents of pages from loop to loop
		 */
1563 1564
		ret = prepare_pages(inode, pages, num_pages,
				    pos, write_bytes,
1565
				    force_page_uptodate);
1566
		if (ret)
J
Josef Bacik 已提交
1567
			break;
C
Chris Mason 已提交
1568

1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580
		ret = lock_and_cleanup_extent_if_need(inode, pages, num_pages,
						      pos, &lockstart, &lockend,
						      &cached_state);
		if (ret < 0) {
			if (ret == -EAGAIN)
				goto again;
			break;
		} else if (ret > 0) {
			need_unlock = true;
			ret = 0;
		}

1581
		copied = btrfs_copy_from_user(pos, num_pages,
J
Josef Bacik 已提交
1582
					   write_bytes, pages, i);
1583 1584 1585 1586 1587 1588 1589 1590

		/*
		 * if we have trouble faulting in the pages, fall
		 * back to one page at a time
		 */
		if (copied < write_bytes)
			nrptrs = 1;

1591 1592
		if (copied == 0) {
			force_page_uptodate = true;
1593
			dirty_pages = 0;
1594 1595
		} else {
			force_page_uptodate = false;
1596 1597
			dirty_pages = DIV_ROUND_UP(copied + offset,
						   PAGE_CACHE_SIZE);
1598
		}
1599

J
Josef Bacik 已提交
1600 1601 1602 1603 1604 1605 1606
		/*
		 * If we had a short copy we need to release the excess delaloc
		 * bytes we reserved.  We need to increment outstanding_extents
		 * because btrfs_delalloc_release_space will decrement it, but
		 * we still have an outstanding extent for the chunk we actually
		 * managed to copy.
		 */
1607
		if (num_pages > dirty_pages) {
1608 1609
			release_bytes = (num_pages - dirty_pages) <<
				PAGE_CACHE_SHIFT;
1610 1611 1612 1613 1614
			if (copied > 0) {
				spin_lock(&BTRFS_I(inode)->lock);
				BTRFS_I(inode)->outstanding_extents++;
				spin_unlock(&BTRFS_I(inode)->lock);
			}
1615
			if (only_release_metadata) {
1616 1617
				btrfs_delalloc_release_metadata(inode,
								release_bytes);
1618 1619 1620 1621 1622 1623
			} else {
				u64 __pos;

				__pos = round_down(pos, root->sectorsize) +
					(dirty_pages << PAGE_CACHE_SHIFT);
				btrfs_delalloc_release_space(inode, __pos,
1624
							     release_bytes);
1625
			}
1626 1627
		}

1628
		release_bytes = dirty_pages << PAGE_CACHE_SHIFT;
1629 1630

		if (copied > 0)
1631 1632 1633
			ret = btrfs_dirty_pages(root, inode, pages,
						dirty_pages, pos, copied,
						NULL);
1634 1635 1636 1637
		if (need_unlock)
			unlock_extent_cached(&BTRFS_I(inode)->io_tree,
					     lockstart, lockend, &cached_state,
					     GFP_NOFS);
1638 1639
		if (ret) {
			btrfs_drop_pages(pages, num_pages);
1640
			break;
1641
		}
C
Chris Mason 已提交
1642

1643
		release_bytes = 0;
1644
		if (only_release_metadata)
1645
			btrfs_end_write_no_snapshoting(root);
1646

1647
		if (only_release_metadata && copied > 0) {
1648 1649
			lockstart = round_down(pos, root->sectorsize);
			lockend = lockstart +
1650 1651 1652 1653 1654 1655 1656 1657
				(dirty_pages << PAGE_CACHE_SHIFT) - 1;

			set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
				       lockend, EXTENT_NORESERVE, NULL,
				       NULL, GFP_NOFS);
			only_release_metadata = false;
		}

1658 1659
		btrfs_drop_pages(pages, num_pages);

J
Josef Bacik 已提交
1660 1661
		cond_resched();

1662
		balance_dirty_pages_ratelimited(inode->i_mapping);
1663
		if (dirty_pages < (root->nodesize >> PAGE_CACHE_SHIFT) + 1)
1664
			btrfs_btree_balance_dirty(root);
1665

1666 1667
		pos += copied;
		num_written += copied;
J
Josef Bacik 已提交
1668
	}
C
Chris Mason 已提交
1669

J
Josef Bacik 已提交
1670 1671
	kfree(pages);

1672
	if (release_bytes) {
1673
		if (only_release_metadata) {
1674
			btrfs_end_write_no_snapshoting(root);
1675
			btrfs_delalloc_release_metadata(inode, release_bytes);
1676
		} else {
1677
			btrfs_delalloc_release_space(inode, pos, release_bytes);
1678
		}
1679 1680
	}

J
Josef Bacik 已提交
1681 1682 1683 1684
	return num_written ? num_written : ret;
}

static ssize_t __btrfs_direct_write(struct kiocb *iocb,
1685
				    struct iov_iter *from,
A
Al Viro 已提交
1686
				    loff_t pos)
J
Josef Bacik 已提交
1687 1688
{
	struct file *file = iocb->ki_filp;
1689
	struct inode *inode = file_inode(file);
J
Josef Bacik 已提交
1690 1691 1692 1693 1694
	ssize_t written;
	ssize_t written_buffered;
	loff_t endbyte;
	int err;

A
Al Viro 已提交
1695
	written = generic_file_direct_write(iocb, from, pos);
J
Josef Bacik 已提交
1696

A
Al Viro 已提交
1697
	if (written < 0 || !iov_iter_count(from))
J
Josef Bacik 已提交
1698 1699 1700
		return written;

	pos += written;
1701
	written_buffered = __btrfs_buffered_write(file, from, pos);
J
Josef Bacik 已提交
1702 1703 1704
	if (written_buffered < 0) {
		err = written_buffered;
		goto out;
C
Chris Mason 已提交
1705
	}
1706 1707 1708 1709
	/*
	 * Ensure all data is persisted. We want the next direct IO read to be
	 * able to read what was just written.
	 */
J
Josef Bacik 已提交
1710
	endbyte = pos + written_buffered - 1;
1711
	err = btrfs_fdatawrite_range(inode, pos, endbyte);
1712 1713
	if (err)
		goto out;
1714
	err = filemap_fdatawait_range(inode->i_mapping, pos, endbyte);
J
Josef Bacik 已提交
1715 1716 1717
	if (err)
		goto out;
	written += written_buffered;
1718
	iocb->ki_pos = pos + written_buffered;
J
Josef Bacik 已提交
1719 1720
	invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT,
				 endbyte >> PAGE_CACHE_SHIFT);
C
Chris Mason 已提交
1721
out:
J
Josef Bacik 已提交
1722 1723
	return written ? written : err;
}
1724

1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742
static void update_time_for_write(struct inode *inode)
{
	struct timespec now;

	if (IS_NOCMTIME(inode))
		return;

	now = current_fs_time(inode->i_sb);
	if (!timespec_equal(&inode->i_mtime, &now))
		inode->i_mtime = now;

	if (!timespec_equal(&inode->i_ctime, &now))
		inode->i_ctime = now;

	if (IS_I_VERSION(inode))
		inode_inc_iversion(inode);
}

A
Al Viro 已提交
1743 1744
static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
				    struct iov_iter *from)
J
Josef Bacik 已提交
1745 1746
{
	struct file *file = iocb->ki_filp;
A
Al Viro 已提交
1747
	struct inode *inode = file_inode(file);
J
Josef Bacik 已提交
1748
	struct btrfs_root *root = BTRFS_I(inode)->root;
1749
	u64 start_pos;
1750
	u64 end_pos;
J
Josef Bacik 已提交
1751
	ssize_t num_written = 0;
1752
	bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host);
1753 1754 1755
	ssize_t err;
	loff_t pos;
	size_t count;
J
Josef Bacik 已提交
1756 1757

	mutex_lock(&inode->i_mutex);
1758 1759
	err = generic_write_checks(iocb, from);
	if (err <= 0) {
J
Josef Bacik 已提交
1760
		mutex_unlock(&inode->i_mutex);
1761
		return err;
J
Josef Bacik 已提交
1762 1763
	}

1764
	current->backing_dev_info = inode_to_bdi(inode);
1765
	err = file_remove_privs(file);
J
Josef Bacik 已提交
1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776
	if (err) {
		mutex_unlock(&inode->i_mutex);
		goto out;
	}

	/*
	 * If BTRFS flips readonly due to some impossible error
	 * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
	 * although we have opened a file as writable, we have
	 * to stop this write operation to ensure FS consistency.
	 */
1777
	if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
J
Josef Bacik 已提交
1778 1779 1780 1781 1782
		mutex_unlock(&inode->i_mutex);
		err = -EROFS;
		goto out;
	}

1783 1784 1785 1786 1787 1788 1789
	/*
	 * We reserve space for updating the inode when we reserve space for the
	 * extent we are going to write, so we will enospc out there.  We don't
	 * need to start yet another transaction to update the inode as we will
	 * update the inode when we finish writing whatever data we write.
	 */
	update_time_for_write(inode);
J
Josef Bacik 已提交
1790

1791 1792
	pos = iocb->ki_pos;
	count = iov_iter_count(from);
1793 1794
	start_pos = round_down(pos, root->sectorsize);
	if (start_pos > i_size_read(inode)) {
1795
		/* Expand hole size to cover write data, preventing empty gap */
1796
		end_pos = round_up(pos + count, root->sectorsize);
1797
		err = btrfs_cont_expand(inode, i_size_read(inode), end_pos);
1798 1799 1800 1801 1802 1803
		if (err) {
			mutex_unlock(&inode->i_mutex);
			goto out;
		}
	}

1804 1805 1806
	if (sync)
		atomic_inc(&BTRFS_I(inode)->sync_writers);

1807
	if (iocb->ki_flags & IOCB_DIRECT) {
A
Al Viro 已提交
1808
		num_written = __btrfs_direct_write(iocb, from, pos);
J
Josef Bacik 已提交
1809
	} else {
A
Al Viro 已提交
1810
		num_written = __btrfs_buffered_write(file, from, pos);
J
Josef Bacik 已提交
1811
		if (num_written > 0)
1812
			iocb->ki_pos = pos + num_written;
J
Josef Bacik 已提交
1813 1814 1815
	}

	mutex_unlock(&inode->i_mutex);
1816

1817
	/*
1818 1819 1820
	 * We also have to set last_sub_trans to the current log transid,
	 * otherwise subsequent syncs to a file that's been synced in this
	 * transaction will appear to have already occured.
1821
	 */
1822
	spin_lock(&BTRFS_I(inode)->lock);
1823
	BTRFS_I(inode)->last_sub_trans = root->log_transid;
1824
	spin_unlock(&BTRFS_I(inode)->lock);
1825
	if (num_written > 0) {
J
Josef Bacik 已提交
1826
		err = generic_write_sync(file, pos, num_written);
1827
		if (err < 0)
1828 1829
			num_written = err;
	}
1830

1831 1832
	if (sync)
		atomic_dec(&BTRFS_I(inode)->sync_writers);
1833
out:
C
Chris Mason 已提交
1834 1835 1836 1837
	current->backing_dev_info = NULL;
	return num_written ? num_written : err;
}

C
Chris Mason 已提交
1838
int btrfs_release_file(struct inode *inode, struct file *filp)
1839
{
S
Sage Weil 已提交
1840 1841
	if (filp->private_data)
		btrfs_ioctl_trans_end(filp);
1842 1843 1844 1845 1846 1847 1848 1849 1850
	/*
	 * ordered_data_close is set by settattr when we are about to truncate
	 * a file from a non-zero size to a zero size.  This tries to
	 * flush down new bytes that may have been written if the
	 * application were using truncate to replace a file in place.
	 */
	if (test_and_clear_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
			       &BTRFS_I(inode)->runtime_flags))
			filemap_flush(inode->i_mapping);
1851 1852 1853
	return 0;
}

1854 1855 1856 1857 1858
static int start_ordered_ops(struct inode *inode, loff_t start, loff_t end)
{
	int ret;

	atomic_inc(&BTRFS_I(inode)->sync_writers);
1859
	ret = btrfs_fdatawrite_range(inode, start, end);
1860 1861 1862 1863 1864
	atomic_dec(&BTRFS_I(inode)->sync_writers);

	return ret;
}

C
Chris Mason 已提交
1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875
/*
 * fsync call for both files and directories.  This logs the inode into
 * the tree log instead of forcing full commits whenever possible.
 *
 * It needs to call filemap_fdatawait so that all ordered extent updates are
 * in the metadata btree are up to date for copying to the log.
 *
 * It drops the inode mutex before doing the tree log commit.  This is an
 * important optimization for directories because holding the mutex prevents
 * new operations on the dir while we write to disk.
 */
1876
int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
C
Chris Mason 已提交
1877
{
1878
	struct dentry *dentry = file->f_path.dentry;
1879
	struct inode *inode = d_inode(dentry);
C
Chris Mason 已提交
1880 1881
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct btrfs_trans_handle *trans;
1882 1883
	struct btrfs_log_ctx ctx;
	int ret = 0;
1884
	bool full_sync = 0;
1885
	u64 len;
C
Chris Mason 已提交
1886

1887 1888 1889 1890 1891
	/*
	 * The range length can be represented by u64, we have to do the typecasts
	 * to avoid signed overflow if it's [0, LLONG_MAX] eg. from fsync()
	 */
	len = (u64)end - (u64)start + 1;
1892
	trace_btrfs_sync_file(file, datasync);
1893

1894 1895 1896
	/*
	 * We write the dirty pages in the range and wait until they complete
	 * out of the ->i_mutex. If so, we can flush the dirty pages by
1897 1898
	 * multi-task, and make the performance up.  See
	 * btrfs_wait_ordered_range for an explanation of the ASYNC check.
1899
	 */
1900
	ret = start_ordered_ops(inode, start, end);
1901 1902 1903
	if (ret)
		return ret;

1904
	mutex_lock(&inode->i_mutex);
M
Miao Xie 已提交
1905
	atomic_inc(&root->log_batch);
1906 1907
	full_sync = test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
			     &BTRFS_I(inode)->runtime_flags);
1908 1909 1910 1911
	/*
	 * We might have have had more pages made dirty after calling
	 * start_ordered_ops and before acquiring the inode's i_mutex.
	 */
1912
	if (full_sync) {
1913 1914 1915 1916 1917 1918
		/*
		 * For a full sync, we need to make sure any ordered operations
		 * start and finish before we start logging the inode, so that
		 * all extents are persisted and the respective file extent
		 * items are in the fs/subvol btree.
		 */
1919
		ret = btrfs_wait_ordered_range(inode, start, len);
1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957
	} else {
		/*
		 * Start any new ordered operations before starting to log the
		 * inode. We will wait for them to finish in btrfs_sync_log().
		 *
		 * Right before acquiring the inode's mutex, we might have new
		 * writes dirtying pages, which won't immediately start the
		 * respective ordered operations - that is done through the
		 * fill_delalloc callbacks invoked from the writepage and
		 * writepages address space operations. So make sure we start
		 * all ordered operations before starting to log our inode. Not
		 * doing this means that while logging the inode, writeback
		 * could start and invoke writepage/writepages, which would call
		 * the fill_delalloc callbacks (cow_file_range,
		 * submit_compressed_extents). These callbacks add first an
		 * extent map to the modified list of extents and then create
		 * the respective ordered operation, which means in
		 * tree-log.c:btrfs_log_inode() we might capture all existing
		 * ordered operations (with btrfs_get_logged_extents()) before
		 * the fill_delalloc callback adds its ordered operation, and by
		 * the time we visit the modified list of extent maps (with
		 * btrfs_log_changed_extents()), we see and process the extent
		 * map they created. We then use the extent map to construct a
		 * file extent item for logging without waiting for the
		 * respective ordered operation to finish - this file extent
		 * item points to a disk location that might not have yet been
		 * written to, containing random data - so after a crash a log
		 * replay will make our inode have file extent items that point
		 * to disk locations containing invalid data, as we returned
		 * success to userspace without waiting for the respective
		 * ordered operation to finish, because it wasn't captured by
		 * btrfs_get_logged_extents().
		 */
		ret = start_ordered_ops(inode, start, end);
	}
	if (ret) {
		mutex_unlock(&inode->i_mutex);
		goto out;
1958
	}
M
Miao Xie 已提交
1959
	atomic_inc(&root->log_batch);
1960

C
Chris Mason 已提交
1961
	/*
1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
	 * If the last transaction that changed this file was before the current
	 * transaction and we have the full sync flag set in our inode, we can
	 * bail out now without any syncing.
	 *
	 * Note that we can't bail out if the full sync flag isn't set. This is
	 * because when the full sync flag is set we start all ordered extents
	 * and wait for them to fully complete - when they complete they update
	 * the inode's last_trans field through:
	 *
	 *     btrfs_finish_ordered_io() ->
	 *         btrfs_update_inode_fallback() ->
	 *             btrfs_update_inode() ->
	 *                 btrfs_set_inode_last_trans()
	 *
	 * So we are sure that last_trans is up to date and can do this check to
	 * bail out safely. For the fast path, when the full sync flag is not
	 * set in our inode, we can not do it because we start only our ordered
	 * extents and don't wait for them to complete (that is when
	 * btrfs_finish_ordered_io runs), so here at this point their last_trans
	 * value might be less than or equals to fs_info->last_trans_committed,
	 * and setting a speculative last_trans for an inode when a buffered
	 * write is made (such as fs_info->generation + 1 for example) would not
	 * be reliable since after setting the value and before fsync is called
	 * any number of transactions can start and commit (transaction kthread
	 * commits the current transaction periodically), and a transaction
	 * commit does not start nor waits for ordered extents to complete.
1988
	 */
J
Josef Bacik 已提交
1989
	smp_mb();
1990
	if (btrfs_inode_in_log(inode, root->fs_info->generation) ||
1991 1992 1993 1994
	    (BTRFS_I(inode)->last_trans <=
	     root->fs_info->last_trans_committed &&
	     (full_sync ||
	      !btrfs_have_ordered_extents_in_range(inode, start, len)))) {
J
Josef Bacik 已提交
1995 1996 1997 1998 1999 2000 2001
		/*
		 * We'v had everything committed since the last time we were
		 * modified so clear this flag in case it was set for whatever
		 * reason, it's no longer relevant.
		 */
		clear_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
			  &BTRFS_I(inode)->runtime_flags);
2002
		mutex_unlock(&inode->i_mutex);
2003 2004 2005 2006
		goto out;
	}

	/*
2007 2008
	 * ok we haven't committed the transaction yet, lets do a commit
	 */
2009
	if (file->private_data)
S
Sage Weil 已提交
2010 2011
		btrfs_ioctl_trans_end(file);

2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022
	/*
	 * We use start here because we will need to wait on the IO to complete
	 * in btrfs_sync_log, which could require joining a transaction (for
	 * example checking cross references in the nocow path).  If we use join
	 * here we could get into a situation where we're waiting on IO to
	 * happen that is blocked on a transaction trying to commit.  With start
	 * we inc the extwriter counter, so we wait for all extwriters to exit
	 * before we start blocking join'ers.  This comment is to keep somebody
	 * from thinking they are super smart and changing this to
	 * btrfs_join_transaction *cough*Josef*cough*.
	 */
2023 2024 2025
	trans = btrfs_start_transaction(root, 0);
	if (IS_ERR(trans)) {
		ret = PTR_ERR(trans);
2026
		mutex_unlock(&inode->i_mutex);
C
Chris Mason 已提交
2027 2028
		goto out;
	}
2029
	trans->sync = true;
2030

2031 2032
	btrfs_init_log_ctx(&ctx);

2033
	ret = btrfs_log_dentry_safe(trans, root, dentry, start, end, &ctx);
2034
	if (ret < 0) {
2035 2036
		/* Fallthrough and commit/free transaction. */
		ret = 1;
2037
	}
C
Chris Mason 已提交
2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048

	/* we've logged all the items and now have a consistent
	 * version of the file in the log.  It is possible that
	 * someone will come in and modify the file, but that's
	 * fine because the log is consistent on disk, and we
	 * have references to all of the file's extents
	 *
	 * It is possible that someone will come in and log the
	 * file again, but that will end up using the synchronization
	 * inside btrfs_sync_log to keep things safe.
	 */
2049
	mutex_unlock(&inode->i_mutex);
C
Chris Mason 已提交
2050

2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069
	/*
	 * If any of the ordered extents had an error, just return it to user
	 * space, so that the application knows some writes didn't succeed and
	 * can take proper action (retry for e.g.). Blindly committing the
	 * transaction in this case, would fool userspace that everything was
	 * successful. And we also want to make sure our log doesn't contain
	 * file extent items pointing to extents that weren't fully written to -
	 * just like in the non fast fsync path, where we check for the ordered
	 * operation's error flag before writing to the log tree and return -EIO
	 * if any of them had this flag set (btrfs_wait_ordered_range) -
	 * therefore we need to check for errors in the ordered operations,
	 * which are indicated by ctx.io_err.
	 */
	if (ctx.io_err) {
		btrfs_end_transaction(trans, root);
		ret = ctx.io_err;
		goto out;
	}

2070
	if (ret != BTRFS_NO_LOG_SYNC) {
2071
		if (!ret) {
2072
			ret = btrfs_sync_log(trans, root, &ctx);
2073
			if (!ret) {
2074
				ret = btrfs_end_transaction(trans, root);
2075
				goto out;
2076
			}
2077
		}
2078
		if (!full_sync) {
2079
			ret = btrfs_wait_ordered_range(inode, start, len);
2080 2081
			if (ret) {
				btrfs_end_transaction(trans, root);
2082
				goto out;
2083
			}
2084 2085
		}
		ret = btrfs_commit_transaction(trans, root);
2086 2087
	} else {
		ret = btrfs_end_transaction(trans, root);
2088
	}
C
Chris Mason 已提交
2089
out:
2090
	return ret > 0 ? -EIO : ret;
C
Chris Mason 已提交
2091 2092
}

2093
static const struct vm_operations_struct btrfs_file_vm_ops = {
2094
	.fault		= filemap_fault,
2095
	.map_pages	= filemap_map_pages,
C
Chris Mason 已提交
2096 2097 2098 2099 2100
	.page_mkwrite	= btrfs_page_mkwrite,
};

static int btrfs_file_mmap(struct file	*filp, struct vm_area_struct *vma)
{
M
Miao Xie 已提交
2101 2102 2103 2104 2105
	struct address_space *mapping = filp->f_mapping;

	if (!mapping->a_ops->readpage)
		return -ENOEXEC;

C
Chris Mason 已提交
2106
	file_accessed(filp);
M
Miao Xie 已提交
2107 2108
	vma->vm_ops = &btrfs_file_vm_ops;

C
Chris Mason 已提交
2109 2110 2111
	return 0;
}

J
Josef Bacik 已提交
2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151
static int hole_mergeable(struct inode *inode, struct extent_buffer *leaf,
			  int slot, u64 start, u64 end)
{
	struct btrfs_file_extent_item *fi;
	struct btrfs_key key;

	if (slot < 0 || slot >= btrfs_header_nritems(leaf))
		return 0;

	btrfs_item_key_to_cpu(leaf, &key, slot);
	if (key.objectid != btrfs_ino(inode) ||
	    key.type != BTRFS_EXTENT_DATA_KEY)
		return 0;

	fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);

	if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
		return 0;

	if (btrfs_file_extent_disk_bytenr(leaf, fi))
		return 0;

	if (key.offset == end)
		return 1;
	if (key.offset + btrfs_file_extent_num_bytes(leaf, fi) == start)
		return 1;
	return 0;
}

static int fill_holes(struct btrfs_trans_handle *trans, struct inode *inode,
		      struct btrfs_path *path, u64 offset, u64 end)
{
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct extent_buffer *leaf;
	struct btrfs_file_extent_item *fi;
	struct extent_map *hole_em;
	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
	struct btrfs_key key;
	int ret;

2152 2153 2154
	if (btrfs_fs_incompat(root->fs_info, NO_HOLES))
		goto out;

J
Josef Bacik 已提交
2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179
	key.objectid = btrfs_ino(inode);
	key.type = BTRFS_EXTENT_DATA_KEY;
	key.offset = offset;

	ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
	if (ret < 0)
		return ret;
	BUG_ON(!ret);

	leaf = path->nodes[0];
	if (hole_mergeable(inode, leaf, path->slots[0]-1, offset, end)) {
		u64 num_bytes;

		path->slots[0]--;
		fi = btrfs_item_ptr(leaf, path->slots[0],
				    struct btrfs_file_extent_item);
		num_bytes = btrfs_file_extent_num_bytes(leaf, fi) +
			end - offset;
		btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
		btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
		btrfs_set_file_extent_offset(leaf, fi, 0);
		btrfs_mark_buffer_dirty(leaf);
		goto out;
	}

2180
	if (hole_mergeable(inode, leaf, path->slots[0], offset, end)) {
J
Josef Bacik 已提交
2181 2182 2183
		u64 num_bytes;

		key.offset = offset;
2184
		btrfs_set_item_key_safe(root->fs_info, path, &key);
J
Josef Bacik 已提交
2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213
		fi = btrfs_item_ptr(leaf, path->slots[0],
				    struct btrfs_file_extent_item);
		num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + end -
			offset;
		btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
		btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
		btrfs_set_file_extent_offset(leaf, fi, 0);
		btrfs_mark_buffer_dirty(leaf);
		goto out;
	}
	btrfs_release_path(path);

	ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
				       0, 0, end - offset, 0, end - offset,
				       0, 0, 0);
	if (ret)
		return ret;

out:
	btrfs_release_path(path);

	hole_em = alloc_extent_map();
	if (!hole_em) {
		btrfs_drop_extent_cache(inode, offset, end - 1, 0);
		set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
			&BTRFS_I(inode)->runtime_flags);
	} else {
		hole_em->start = offset;
		hole_em->len = end - offset;
J
Josef Bacik 已提交
2214
		hole_em->ram_bytes = hole_em->len;
J
Josef Bacik 已提交
2215 2216 2217 2218
		hole_em->orig_start = offset;

		hole_em->block_start = EXTENT_MAP_HOLE;
		hole_em->block_len = 0;
2219
		hole_em->orig_block_len = 0;
J
Josef Bacik 已提交
2220 2221 2222 2223 2224 2225 2226
		hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
		hole_em->compress_type = BTRFS_COMPRESS_NONE;
		hole_em->generation = trans->transid;

		do {
			btrfs_drop_extent_cache(inode, offset, end - 1, 0);
			write_lock(&em_tree->lock);
J
Josef Bacik 已提交
2227
			ret = add_extent_mapping(em_tree, hole_em, 1);
J
Josef Bacik 已提交
2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238
			write_unlock(&em_tree->lock);
		} while (ret == -EEXIST);
		free_extent_map(hole_em);
		if (ret)
			set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
				&BTRFS_I(inode)->runtime_flags);
	}

	return 0;
}

2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269
/*
 * Find a hole extent on given inode and change start/len to the end of hole
 * extent.(hole/vacuum extent whose em->start <= start &&
 *	   em->start + em->len > start)
 * When a hole extent is found, return 1 and modify start/len.
 */
static int find_first_non_hole(struct inode *inode, u64 *start, u64 *len)
{
	struct extent_map *em;
	int ret = 0;

	em = btrfs_get_extent(inode, NULL, 0, *start, *len, 0);
	if (IS_ERR_OR_NULL(em)) {
		if (!em)
			ret = -ENOMEM;
		else
			ret = PTR_ERR(em);
		return ret;
	}

	/* Hole or vacuum extent(only exists in no-hole mode) */
	if (em->block_start == EXTENT_MAP_HOLE) {
		ret = 1;
		*len = em->start + em->len > *start + *len ?
		       0 : *start + *len - em->start - em->len;
		*start = em->start + em->len;
	}
	free_extent_map(em);
	return ret;
}

J
Josef Bacik 已提交
2270 2271 2272 2273 2274 2275 2276
static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
{
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct extent_state *cached_state = NULL;
	struct btrfs_path *path;
	struct btrfs_block_rsv *rsv;
	struct btrfs_trans_handle *trans;
2277 2278 2279 2280 2281 2282
	u64 lockstart;
	u64 lockend;
	u64 tail_start;
	u64 tail_len;
	u64 orig_start = offset;
	u64 cur_offset;
J
Josef Bacik 已提交
2283 2284 2285 2286
	u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
	u64 drop_end;
	int ret = 0;
	int err = 0;
2287
	unsigned int rsv_count;
2288
	bool same_page;
2289
	bool no_holes = btrfs_fs_incompat(root->fs_info, NO_HOLES);
2290
	u64 ino_size;
2291 2292
	bool truncated_page = false;
	bool updated_inode = false;
J
Josef Bacik 已提交
2293

2294 2295 2296
	ret = btrfs_wait_ordered_range(inode, offset, len);
	if (ret)
		return ret;
J
Josef Bacik 已提交
2297 2298

	mutex_lock(&inode->i_mutex);
2299
	ino_size = round_up(inode->i_size, PAGE_CACHE_SIZE);
2300 2301 2302 2303 2304 2305 2306 2307 2308
	ret = find_first_non_hole(inode, &offset, &len);
	if (ret < 0)
		goto out_only_mutex;
	if (ret && !len) {
		/* Already in a large hole */
		ret = 0;
		goto out_only_mutex;
	}

2309
	lockstart = round_up(offset, BTRFS_I(inode)->root->sectorsize);
2310 2311 2312 2313 2314
	lockend = round_down(offset + len,
			     BTRFS_I(inode)->root->sectorsize) - 1;
	same_page = ((offset >> PAGE_CACHE_SHIFT) ==
		    ((offset + len - 1) >> PAGE_CACHE_SHIFT));

2315 2316 2317 2318
	/*
	 * We needn't truncate any page which is beyond the end of the file
	 * because we are sure there is no data there.
	 */
J
Josef Bacik 已提交
2319 2320 2321 2322 2323
	/*
	 * Only do this if we are in the same page and we aren't doing the
	 * entire page.
	 */
	if (same_page && len < PAGE_CACHE_SIZE) {
2324 2325
		if (offset < ino_size) {
			truncated_page = true;
2326
			ret = btrfs_truncate_page(inode, offset, len, 0);
2327 2328 2329
		} else {
			ret = 0;
		}
2330
		goto out_only_mutex;
J
Josef Bacik 已提交
2331 2332 2333
	}

	/* zero back part of the first page */
2334
	if (offset < ino_size) {
2335
		truncated_page = true;
2336 2337 2338 2339 2340
		ret = btrfs_truncate_page(inode, offset, 0, 0);
		if (ret) {
			mutex_unlock(&inode->i_mutex);
			return ret;
		}
J
Josef Bacik 已提交
2341 2342
	}

2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370
	/* Check the aligned pages after the first unaligned page,
	 * if offset != orig_start, which means the first unaligned page
	 * including serveral following pages are already in holes,
	 * the extra check can be skipped */
	if (offset == orig_start) {
		/* after truncate page, check hole again */
		len = offset + len - lockstart;
		offset = lockstart;
		ret = find_first_non_hole(inode, &offset, &len);
		if (ret < 0)
			goto out_only_mutex;
		if (ret && !len) {
			ret = 0;
			goto out_only_mutex;
		}
		lockstart = offset;
	}

	/* Check the tail unaligned part is in a hole */
	tail_start = lockend + 1;
	tail_len = offset + len - tail_start;
	if (tail_len) {
		ret = find_first_non_hole(inode, &tail_start, &tail_len);
		if (unlikely(ret < 0))
			goto out_only_mutex;
		if (!ret) {
			/* zero the front end of the last page */
			if (tail_start + tail_len < ino_size) {
2371
				truncated_page = true;
2372 2373 2374 2375
				ret = btrfs_truncate_page(inode,
						tail_start + tail_len, 0, 1);
				if (ret)
					goto out_only_mutex;
2376
			}
M
Miao Xie 已提交
2377
		}
J
Josef Bacik 已提交
2378 2379 2380
	}

	if (lockend < lockstart) {
2381 2382
		ret = 0;
		goto out_only_mutex;
J
Josef Bacik 已提交
2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399
	}

	while (1) {
		struct btrfs_ordered_extent *ordered;

		truncate_pagecache_range(inode, lockstart, lockend);

		lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
				 0, &cached_state);
		ordered = btrfs_lookup_first_ordered_extent(inode, lockend);

		/*
		 * We need to make sure we have no ordered extents in this range
		 * and nobody raced in and read a page in this range, if we did
		 * we need to try again.
		 */
		if ((!ordered ||
2400
		    (ordered->file_offset + ordered->len <= lockstart ||
J
Josef Bacik 已提交
2401
		     ordered->file_offset > lockend)) &&
2402
		     !btrfs_page_exists_in_range(inode, lockstart, lockend)) {
J
Josef Bacik 已提交
2403 2404 2405 2406 2407 2408 2409 2410
			if (ordered)
				btrfs_put_ordered_extent(ordered);
			break;
		}
		if (ordered)
			btrfs_put_ordered_extent(ordered);
		unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
				     lockend, &cached_state, GFP_NOFS);
2411 2412 2413 2414 2415 2416
		ret = btrfs_wait_ordered_range(inode, lockstart,
					       lockend - lockstart + 1);
		if (ret) {
			mutex_unlock(&inode->i_mutex);
			return ret;
		}
J
Josef Bacik 已提交
2417 2418 2419 2420 2421 2422 2423 2424
	}

	path = btrfs_alloc_path();
	if (!path) {
		ret = -ENOMEM;
		goto out;
	}

2425
	rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
J
Josef Bacik 已提交
2426 2427 2428 2429 2430 2431 2432 2433 2434 2435
	if (!rsv) {
		ret = -ENOMEM;
		goto out_free;
	}
	rsv->size = btrfs_calc_trunc_metadata_size(root, 1);
	rsv->failfast = 1;

	/*
	 * 1 - update the inode
	 * 1 - removing the extents in the range
2436
	 * 1 - adding the hole extent if no_holes isn't set
J
Josef Bacik 已提交
2437
	 */
2438 2439
	rsv_count = no_holes ? 2 : 3;
	trans = btrfs_start_transaction(root, rsv_count);
J
Josef Bacik 已提交
2440 2441 2442 2443 2444 2445 2446 2447 2448 2449
	if (IS_ERR(trans)) {
		err = PTR_ERR(trans);
		goto out_free;
	}

	ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
				      min_size);
	BUG_ON(ret);
	trans->block_rsv = rsv;

2450 2451
	cur_offset = lockstart;
	len = lockend - cur_offset;
J
Josef Bacik 已提交
2452 2453 2454
	while (cur_offset < lockend) {
		ret = __btrfs_drop_extents(trans, root, inode, path,
					   cur_offset, lockend + 1,
2455
					   &drop_end, 1, 0, 0, NULL);
J
Josef Bacik 已提交
2456 2457 2458 2459 2460
		if (ret != -ENOSPC)
			break;

		trans->block_rsv = &root->fs_info->trans_block_rsv;

2461 2462 2463 2464 2465 2466 2467
		if (cur_offset < ino_size) {
			ret = fill_holes(trans, inode, path, cur_offset,
					 drop_end);
			if (ret) {
				err = ret;
				break;
			}
J
Josef Bacik 已提交
2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478
		}

		cur_offset = drop_end;

		ret = btrfs_update_inode(trans, root, inode);
		if (ret) {
			err = ret;
			break;
		}

		btrfs_end_transaction(trans, root);
2479
		btrfs_btree_balance_dirty(root);
J
Josef Bacik 已提交
2480

2481
		trans = btrfs_start_transaction(root, rsv_count);
J
Josef Bacik 已提交
2482 2483 2484 2485 2486 2487 2488 2489 2490 2491
		if (IS_ERR(trans)) {
			ret = PTR_ERR(trans);
			trans = NULL;
			break;
		}

		ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
					      rsv, min_size);
		BUG_ON(ret);	/* shouldn't happen */
		trans->block_rsv = rsv;
2492 2493 2494 2495 2496 2497 2498 2499

		ret = find_first_non_hole(inode, &cur_offset, &len);
		if (unlikely(ret < 0))
			break;
		if (ret && !len) {
			ret = 0;
			break;
		}
J
Josef Bacik 已提交
2500 2501 2502 2503 2504 2505 2506 2507
	}

	if (ret) {
		err = ret;
		goto out_trans;
	}

	trans->block_rsv = &root->fs_info->trans_block_rsv;
2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520
	/*
	 * If we are using the NO_HOLES feature we might have had already an
	 * hole that overlaps a part of the region [lockstart, lockend] and
	 * ends at (or beyond) lockend. Since we have no file extent items to
	 * represent holes, drop_end can be less than lockend and so we must
	 * make sure we have an extent map representing the existing hole (the
	 * call to __btrfs_drop_extents() might have dropped the existing extent
	 * map representing the existing hole), otherwise the fast fsync path
	 * will not record the existence of the hole region
	 * [existing_hole_start, lockend].
	 */
	if (drop_end <= lockend)
		drop_end = lockend + 1;
2521 2522 2523 2524 2525 2526
	/*
	 * Don't insert file hole extent item if it's for a range beyond eof
	 * (because it's useless) or if it represents a 0 bytes range (when
	 * cur_offset == drop_end).
	 */
	if (cur_offset < ino_size && cur_offset < drop_end) {
2527 2528 2529 2530 2531
		ret = fill_holes(trans, inode, path, cur_offset, drop_end);
		if (ret) {
			err = ret;
			goto out_trans;
		}
J
Josef Bacik 已提交
2532 2533 2534 2535 2536 2537
	}

out_trans:
	if (!trans)
		goto out_free;

2538 2539 2540
	inode_inc_iversion(inode);
	inode->i_mtime = inode->i_ctime = CURRENT_TIME;

J
Josef Bacik 已提交
2541 2542
	trans->block_rsv = &root->fs_info->trans_block_rsv;
	ret = btrfs_update_inode(trans, root, inode);
2543
	updated_inode = true;
J
Josef Bacik 已提交
2544
	btrfs_end_transaction(trans, root);
2545
	btrfs_btree_balance_dirty(root);
J
Josef Bacik 已提交
2546 2547 2548 2549 2550 2551
out_free:
	btrfs_free_path(path);
	btrfs_free_block_rsv(root, rsv);
out:
	unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
			     &cached_state, GFP_NOFS);
2552
out_only_mutex:
2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568
	if (!updated_inode && truncated_page && !ret && !err) {
		/*
		 * If we only end up zeroing part of a page, we still need to
		 * update the inode item, so that all the time fields are
		 * updated as well as the necessary btrfs inode in memory fields
		 * for detecting, at fsync time, if the inode isn't yet in the
		 * log tree or it's there but not up to date.
		 */
		trans = btrfs_start_transaction(root, 1);
		if (IS_ERR(trans)) {
			err = PTR_ERR(trans);
		} else {
			err = btrfs_update_inode(trans, root, inode);
			ret = btrfs_end_transaction(trans, root);
		}
	}
J
Josef Bacik 已提交
2569 2570 2571 2572 2573 2574
	mutex_unlock(&inode->i_mutex);
	if (ret && !err)
		err = ret;
	return err;
}

2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614
/* Helper structure to record which range is already reserved */
struct falloc_range {
	struct list_head list;
	u64 start;
	u64 len;
};

/*
 * Helper function to add falloc range
 *
 * Caller should have locked the larger range of extent containing
 * [start, len)
 */
static int add_falloc_range(struct list_head *head, u64 start, u64 len)
{
	struct falloc_range *prev = NULL;
	struct falloc_range *range = NULL;

	if (list_empty(head))
		goto insert;

	/*
	 * As fallocate iterate by bytenr order, we only need to check
	 * the last range.
	 */
	prev = list_entry(head->prev, struct falloc_range, list);
	if (prev->start + prev->len == start) {
		prev->len += len;
		return 0;
	}
insert:
	range = kmalloc(sizeof(*range), GFP_NOFS);
	if (!range)
		return -ENOMEM;
	range->start = start;
	range->len = len;
	list_add_tail(&range->list, head);
	return 0;
}

2615 2616 2617
static long btrfs_fallocate(struct file *file, int mode,
			    loff_t offset, loff_t len)
{
A
Al Viro 已提交
2618
	struct inode *inode = file_inode(file);
2619
	struct extent_state *cached_state = NULL;
2620 2621 2622
	struct falloc_range *range;
	struct falloc_range *tmp;
	struct list_head reserve_list;
2623 2624 2625 2626 2627 2628
	u64 cur_offset;
	u64 last_byte;
	u64 alloc_start;
	u64 alloc_end;
	u64 alloc_hint = 0;
	u64 locked_end;
2629
	u64 actual_end = 0;
2630
	struct extent_map *em;
2631
	int blocksize = BTRFS_I(inode)->root->sectorsize;
2632 2633
	int ret;

2634 2635
	alloc_start = round_down(offset, blocksize);
	alloc_end = round_up(offset + len, blocksize);
2636

J
Josef Bacik 已提交
2637 2638
	/* Make sure we aren't being give some crap mode */
	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
2639 2640
		return -EOPNOTSUPP;

J
Josef Bacik 已提交
2641 2642 2643
	if (mode & FALLOC_FL_PUNCH_HOLE)
		return btrfs_punch_hole(inode, offset, len);

2644
	/*
2645 2646 2647
	 * Only trigger disk allocation, don't trigger qgroup reserve
	 *
	 * For qgroup space, it will be checked later.
2648
	 */
2649 2650
	ret = btrfs_alloc_data_chunk_ondemand(inode, alloc_end - alloc_start);
	if (ret < 0)
2651 2652
		return ret;

2653 2654 2655 2656 2657
	mutex_lock(&inode->i_mutex);
	ret = inode_newsize_ok(inode, alloc_end);
	if (ret)
		goto out;

2658 2659 2660 2661 2662 2663 2664
	/*
	 * TODO: Move these two operations after we have checked
	 * accurate reserved space, or fallocate can still fail but
	 * with page truncated or size expanded.
	 *
	 * But that's a minor problem and won't do much harm BTW.
	 */
2665
	if (alloc_start > inode->i_size) {
2666 2667
		ret = btrfs_cont_expand(inode, i_size_read(inode),
					alloc_start);
2668 2669
		if (ret)
			goto out;
2670
	} else if (offset + len > inode->i_size) {
2671 2672 2673 2674 2675 2676 2677 2678
		/*
		 * If we are fallocating from the end of the file onward we
		 * need to zero out the end of the page if i_size lands in the
		 * middle of a page.
		 */
		ret = btrfs_truncate_page(inode, inode->i_size, 0, 0);
		if (ret)
			goto out;
2679 2680
	}

2681 2682 2683 2684
	/*
	 * wait for ordered IO before we have any locks.  We'll loop again
	 * below with the locks held.
	 */
2685 2686 2687 2688
	ret = btrfs_wait_ordered_range(inode, alloc_start,
				       alloc_end - alloc_start);
	if (ret)
		goto out;
2689

2690 2691 2692 2693 2694 2695 2696 2697
	locked_end = alloc_end - 1;
	while (1) {
		struct btrfs_ordered_extent *ordered;

		/* the extent lock is ordered inside the running
		 * transaction
		 */
		lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
2698
				 locked_end, 0, &cached_state);
2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711
		ordered = btrfs_lookup_first_ordered_extent(inode,
							    alloc_end - 1);
		if (ordered &&
		    ordered->file_offset + ordered->len > alloc_start &&
		    ordered->file_offset < alloc_end) {
			btrfs_put_ordered_extent(ordered);
			unlock_extent_cached(&BTRFS_I(inode)->io_tree,
					     alloc_start, locked_end,
					     &cached_state, GFP_NOFS);
			/*
			 * we can't wait on the range with the transaction
			 * running or with the extent lock held
			 */
2712 2713 2714 2715
			ret = btrfs_wait_ordered_range(inode, alloc_start,
						       alloc_end - alloc_start);
			if (ret)
				goto out;
2716 2717 2718 2719 2720 2721 2722
		} else {
			if (ordered)
				btrfs_put_ordered_extent(ordered);
			break;
		}
	}

2723 2724
	/* First, check if we exceed the qgroup limit */
	INIT_LIST_HEAD(&reserve_list);
2725 2726 2727 2728
	cur_offset = alloc_start;
	while (1) {
		em = btrfs_get_extent(inode, NULL, 0, cur_offset,
				      alloc_end - cur_offset, 0);
2729 2730 2731 2732 2733 2734 2735
		if (IS_ERR_OR_NULL(em)) {
			if (!em)
				ret = -ENOMEM;
			else
				ret = PTR_ERR(em);
			break;
		}
2736
		last_byte = min(extent_map_end(em), alloc_end);
2737
		actual_end = min_t(u64, extent_map_end(em), offset + len);
2738
		last_byte = ALIGN(last_byte, blocksize);
2739 2740 2741
		if (em->block_start == EXTENT_MAP_HOLE ||
		    (cur_offset >= inode->i_size &&
		     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
2742 2743 2744 2745 2746
			ret = add_falloc_range(&reserve_list, cur_offset,
					       last_byte - cur_offset);
			if (ret < 0) {
				free_extent_map(em);
				break;
2747
			}
2748 2749 2750 2751
			ret = btrfs_qgroup_reserve_data(inode, cur_offset,
					last_byte - cur_offset);
			if (ret < 0)
				break;
2752 2753 2754
		}
		free_extent_map(em);
		cur_offset = last_byte;
2755
		if (cur_offset >= alloc_end)
2756
			break;
2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796
	}

	/*
	 * If ret is still 0, means we're OK to fallocate.
	 * Or just cleanup the list and exit.
	 */
	list_for_each_entry_safe(range, tmp, &reserve_list, list) {
		if (!ret)
			ret = btrfs_prealloc_file_range(inode, mode,
					range->start,
					range->len, 1 << inode->i_blkbits,
					offset + len, &alloc_hint);
		list_del(&range->list);
		kfree(range);
	}
	if (ret < 0)
		goto out_unlock;

	if (actual_end > inode->i_size &&
	    !(mode & FALLOC_FL_KEEP_SIZE)) {
		struct btrfs_trans_handle *trans;
		struct btrfs_root *root = BTRFS_I(inode)->root;

		/*
		 * We didn't need to allocate any more space, but we
		 * still extended the size of the file so we need to
		 * update i_size and the inode item.
		 */
		trans = btrfs_start_transaction(root, 1);
		if (IS_ERR(trans)) {
			ret = PTR_ERR(trans);
		} else {
			inode->i_ctime = CURRENT_TIME;
			i_size_write(inode, actual_end);
			btrfs_ordered_update_i_size(inode, actual_end, NULL);
			ret = btrfs_update_inode(trans, root, inode);
			if (ret)
				btrfs_end_transaction(trans, root);
			else
				ret = btrfs_end_transaction(trans, root);
2797 2798
		}
	}
2799
out_unlock:
2800 2801 2802
	unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
			     &cached_state, GFP_NOFS);
out:
2803 2804 2805 2806 2807 2808 2809 2810
	/*
	 * As we waited the extent range, the data_rsv_map must be empty
	 * in the range, as written data range will be released from it.
	 * And for prealloacted extent, it will also be released when
	 * its metadata is written.
	 * So this is completely used as cleanup.
	 */
	btrfs_qgroup_free_data(inode, alloc_start, alloc_end - alloc_start);
2811
	mutex_unlock(&inode->i_mutex);
2812
	/* Let go of our reservation. */
2813 2814
	btrfs_free_reserved_data_space(inode, alloc_start,
				       alloc_end - alloc_start);
2815 2816 2817
	return ret;
}

2818
static int find_desired_extent(struct inode *inode, loff_t *offset, int whence)
J
Josef Bacik 已提交
2819 2820
{
	struct btrfs_root *root = BTRFS_I(inode)->root;
2821
	struct extent_map *em = NULL;
J
Josef Bacik 已提交
2822
	struct extent_state *cached_state = NULL;
L
Liu Bo 已提交
2823 2824 2825 2826
	u64 lockstart;
	u64 lockend;
	u64 start;
	u64 len;
J
Josef Bacik 已提交
2827 2828
	int ret = 0;

L
Liu Bo 已提交
2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839
	if (inode->i_size == 0)
		return -ENXIO;

	/*
	 * *offset can be negative, in this case we start finding DATA/HOLE from
	 * the very start of the file.
	 */
	start = max_t(loff_t, 0, *offset);

	lockstart = round_down(start, root->sectorsize);
	lockend = round_up(i_size_read(inode), root->sectorsize);
J
Josef Bacik 已提交
2840 2841
	if (lockend <= lockstart)
		lockend = lockstart + root->sectorsize;
L
Liu Bo 已提交
2842
	lockend--;
J
Josef Bacik 已提交
2843 2844 2845
	len = lockend - lockstart + 1;

	lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend, 0,
2846
			 &cached_state);
J
Josef Bacik 已提交
2847

2848
	while (start < inode->i_size) {
J
Josef Bacik 已提交
2849 2850
		em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0);
		if (IS_ERR(em)) {
2851
			ret = PTR_ERR(em);
2852
			em = NULL;
J
Josef Bacik 已提交
2853 2854 2855
			break;
		}

2856 2857 2858 2859 2860 2861 2862 2863
		if (whence == SEEK_HOLE &&
		    (em->block_start == EXTENT_MAP_HOLE ||
		     test_bit(EXTENT_FLAG_PREALLOC, &em->flags)))
			break;
		else if (whence == SEEK_DATA &&
			   (em->block_start != EXTENT_MAP_HOLE &&
			    !test_bit(EXTENT_FLAG_PREALLOC, &em->flags)))
			break;
J
Josef Bacik 已提交
2864 2865 2866

		start = em->start + em->len;
		free_extent_map(em);
2867
		em = NULL;
J
Josef Bacik 已提交
2868 2869
		cond_resched();
	}
2870 2871 2872 2873 2874 2875 2876
	free_extent_map(em);
	if (!ret) {
		if (whence == SEEK_DATA && start >= inode->i_size)
			ret = -ENXIO;
		else
			*offset = min_t(loff_t, start, inode->i_size);
	}
J
Josef Bacik 已提交
2877 2878 2879 2880 2881
	unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
			     &cached_state, GFP_NOFS);
	return ret;
}

2882
static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
J
Josef Bacik 已提交
2883 2884 2885 2886 2887
{
	struct inode *inode = file->f_mapping->host;
	int ret;

	mutex_lock(&inode->i_mutex);
2888
	switch (whence) {
J
Josef Bacik 已提交
2889 2890
	case SEEK_END:
	case SEEK_CUR:
2891
		offset = generic_file_llseek(file, offset, whence);
J
Josef Bacik 已提交
2892 2893 2894
		goto out;
	case SEEK_DATA:
	case SEEK_HOLE:
2895 2896 2897 2898 2899
		if (offset >= i_size_read(inode)) {
			mutex_unlock(&inode->i_mutex);
			return -ENXIO;
		}

2900
		ret = find_desired_extent(inode, &offset, whence);
J
Josef Bacik 已提交
2901 2902 2903 2904 2905 2906
		if (ret) {
			mutex_unlock(&inode->i_mutex);
			return ret;
		}
	}

J
Jie Liu 已提交
2907
	offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
J
Josef Bacik 已提交
2908 2909 2910 2911 2912
out:
	mutex_unlock(&inode->i_mutex);
	return offset;
}

2913
const struct file_operations btrfs_file_operations = {
J
Josef Bacik 已提交
2914
	.llseek		= btrfs_file_llseek,
2915
	.read_iter      = generic_file_read_iter,
C
Chris Mason 已提交
2916
	.splice_read	= generic_file_splice_read,
A
Al Viro 已提交
2917
	.write_iter	= btrfs_file_write_iter,
C
Chris Mason 已提交
2918
	.mmap		= btrfs_file_mmap,
C
Chris Mason 已提交
2919
	.open		= generic_file_open,
2920
	.release	= btrfs_release_file,
C
Chris Mason 已提交
2921
	.fsync		= btrfs_sync_file,
2922
	.fallocate	= btrfs_fallocate,
C
Christoph Hellwig 已提交
2923
	.unlocked_ioctl	= btrfs_ioctl,
C
Chris Mason 已提交
2924
#ifdef CONFIG_COMPAT
C
Christoph Hellwig 已提交
2925
	.compat_ioctl	= btrfs_ioctl,
C
Chris Mason 已提交
2926
#endif
2927
	.copy_file_range = btrfs_copy_file_range,
2928
	.clone_file_range = btrfs_clone_file_range,
C
Chris Mason 已提交
2929
};
2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947

void btrfs_auto_defrag_exit(void)
{
	if (btrfs_inode_defrag_cachep)
		kmem_cache_destroy(btrfs_inode_defrag_cachep);
}

int btrfs_auto_defrag_init(void)
{
	btrfs_inode_defrag_cachep = kmem_cache_create("btrfs_inode_defrag",
					sizeof(struct inode_defrag), 0,
					SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
					NULL);
	if (!btrfs_inode_defrag_cachep)
		return -ENOMEM;

	return 0;
}
2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973

int btrfs_fdatawrite_range(struct inode *inode, loff_t start, loff_t end)
{
	int ret;

	/*
	 * So with compression we will find and lock a dirty page and clear the
	 * first one as dirty, setup an async extent, and immediately return
	 * with the entire range locked but with nobody actually marked with
	 * writeback.  So we can't just filemap_write_and_wait_range() and
	 * expect it to work since it will just kick off a thread to do the
	 * actual work.  So we need to call filemap_fdatawrite_range _again_
	 * since it will wait on the page lock, which won't be unlocked until
	 * after the pages have been marked as writeback and so we're good to go
	 * from there.  We have to do this otherwise we'll miss the ordered
	 * extents and that results in badness.  Please Josef, do not think you
	 * know better and pull this out at some point in the future, it is
	 * right and you are wrong.
	 */
	ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
	if (!ret && test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
			     &BTRFS_I(inode)->runtime_flags))
		ret = filemap_fdatawrite_range(inode->i_mapping, start, end);

	return ret;
}