file.c 68.8 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/aio.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 "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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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);

		if (need_resched()) {
			spin_unlock(&fs_info->defrag_inodes_lock);
			cond_resched();
			spin_lock(&fs_info->defrag_inodes_lock);
		}

		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;
	btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
	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;
	btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
	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
		 *
		 * Disable pagefault to avoid recursive lock since
		 * the pages are already locked
		 */
		pagefault_disable();
		copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
		pagefault_enable();
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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_aio_write to fault page */
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		if (unlikely(copied == 0))
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			break;
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		if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
			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
		 * clear it here
		 */
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		ClearPageChecked(pages[i]);
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		unlock_page(pages[i]);
		mark_page_accessed(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);
581 582
				break;
			}
583 584
			start = em->start + em->len;
			if (testend)
585 586
				len = start + len - (em->start + em->len);
			free_extent_map(em);
C
Chris Mason 已提交
587
			write_unlock(&em_tree->lock);
588 589
			continue;
		}
C
Chris Mason 已提交
590
		compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
591
		clear_bit(EXTENT_FLAG_PINNED, &em->flags);
L
Liu Bo 已提交
592
		clear_bit(EXTENT_FLAG_LOGGING, &flags);
J
Josef Bacik 已提交
593
		modified = !list_empty(&em->list);
594 595
		if (no_splits)
			goto next;
596

597
		if (em->start < start) {
598 599
			split->start = em->start;
			split->len = start - em->start;
600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619

			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
620
			split->generation = gen;
621
			split->bdev = em->bdev;
622
			split->flags = flags;
623
			split->compress_type = em->compress_type;
624
			replace_extent_mapping(em_tree, em, split, modified);
625 626 627 628
			free_extent_map(split);
			split = split2;
			split2 = NULL;
		}
629
		if (testend && em->start + em->len > start + len) {
630 631 632 633 634
			u64 diff = start + len - em->start;

			split->start = start + len;
			split->len = em->start + em->len - (start + len);
			split->bdev = em->bdev;
635
			split->flags = flags;
636
			split->compress_type = em->compress_type;
J
Josef Bacik 已提交
637
			split->generation = gen;
638 639 640

			if (em->block_start < EXTENT_MAP_LAST_BYTE) {
				split->orig_block_len = max(em->block_len,
641
						    em->orig_block_len);
642

643 644 645 646 647 648 649 650 651 652 653
				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
654
			} else {
655 656 657 658 659
				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
660
			}
661

662 663 664 665 666 667 668 669
			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 */
			}
670 671 672
			free_extent_map(split);
			split = NULL;
		}
673
next:
674 675
		if (extent_map_in_tree(em))
			remove_extent_mapping(em_tree, em);
676
		write_unlock(&em_tree->lock);
677

678 679 680 681 682
		/* once for us */
		free_extent_map(em);
		/* once for the tree*/
		free_extent_map(em);
	}
683 684 685 686
	if (split)
		free_extent_map(split);
	if (split2)
		free_extent_map(split2);
687 688
}

C
Chris Mason 已提交
689 690 691 692 693 694 695 696 697
/*
 * 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
698 699 700
int __btrfs_drop_extents(struct btrfs_trans_handle *trans,
			 struct btrfs_root *root, struct inode *inode,
			 struct btrfs_path *path, u64 start, u64 end,
701 702 703 704
			 u64 *drop_end, int drop_cache,
			 int replace_extent,
			 u32 extent_item_size,
			 int *key_inserted)
C
Chris Mason 已提交
705
{
706
	struct extent_buffer *leaf;
Y
Yan, Zheng 已提交
707
	struct btrfs_file_extent_item *fi;
708
	struct btrfs_key key;
Y
Yan, Zheng 已提交
709
	struct btrfs_key new_key;
L
Li Zefan 已提交
710
	u64 ino = btrfs_ino(inode);
Y
Yan, Zheng 已提交
711 712 713 714 715 716 717 718
	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
719
	int recow;
720
	int ret;
721
	int modify_tree = -1;
J
Josef Bacik 已提交
722
	int update_refs = (root->ref_cows || root == root->fs_info->tree_root);
723
	int found = 0;
724
	int leafs_visited = 0;
C
Chris Mason 已提交
725

C
Chris Mason 已提交
726 727
	if (drop_cache)
		btrfs_drop_extent_cache(inode, start, end - 1, 0);
728

729
	if (start >= BTRFS_I(inode)->disk_i_size && !replace_extent)
730 731
		modify_tree = 0;

C
Chris Mason 已提交
732
	while (1) {
C
Chris Mason 已提交
733
		recow = 0;
L
Li Zefan 已提交
734
		ret = btrfs_lookup_file_extent(trans, root, path, ino,
735
					       search_start, modify_tree);
C
Chris Mason 已提交
736
		if (ret < 0)
Y
Yan, Zheng 已提交
737 738 739 740
			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
741
			if (key.objectid == ino &&
Y
Yan, Zheng 已提交
742 743
			    key.type == BTRFS_EXTENT_DATA_KEY)
				path->slots[0]--;
C
Chris Mason 已提交
744
		}
Y
Yan, Zheng 已提交
745
		ret = 0;
746
		leafs_visited++;
747
next_slot:
748
		leaf = path->nodes[0];
Y
Yan, Zheng 已提交
749 750 751 752 753 754 755 756
		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;
757
			}
758
			leafs_visited++;
Y
Yan, Zheng 已提交
759 760 761 762 763
			leaf = path->nodes[0];
			recow = 1;
		}

		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
L
Li Zefan 已提交
764
		if (key.objectid > ino ||
Y
Yan, Zheng 已提交
765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780
		    key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
			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 +
781 782
				btrfs_file_extent_inline_len(leaf,
						     path->slots[0], fi);
783
		} else {
Y
Yan, Zheng 已提交
784
			WARN_ON(1);
785
			extent_end = search_start;
C
Chris Mason 已提交
786 787
		}

Y
Yan, Zheng 已提交
788 789
		if (extent_end <= search_start) {
			path->slots[0]++;
790
			goto next_slot;
C
Chris Mason 已提交
791 792
		}

793
		found = 1;
Y
Yan, Zheng 已提交
794
		search_start = max(key.offset, start);
795 796
		if (recow || !modify_tree) {
			modify_tree = -1;
797
			btrfs_release_path(path);
Y
Yan, Zheng 已提交
798
			continue;
C
Chris Mason 已提交
799
		}
Y
Yan Zheng 已提交
800

Y
Yan, Zheng 已提交
801 802 803 804 805 806
		/*
		 *     | - range to drop - |
		 *  | -------- extent -------- |
		 */
		if (start > key.offset && end < extent_end) {
			BUG_ON(del_nr > 0);
807 808 809 810
			if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
				ret = -EINVAL;
				break;
			}
Y
Yan, Zheng 已提交
811 812 813 814 815 816

			memcpy(&new_key, &key, sizeof(new_key));
			new_key.offset = start;
			ret = btrfs_duplicate_item(trans, root, path,
						   &new_key);
			if (ret == -EAGAIN) {
817
				btrfs_release_path(path);
Y
Yan, Zheng 已提交
818
				continue;
Y
Yan Zheng 已提交
819
			}
Y
Yan, Zheng 已提交
820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837
			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
838
			if (update_refs && disk_bytenr > 0) {
839
				ret = btrfs_inc_extent_ref(trans, root,
Y
Yan, Zheng 已提交
840 841 842
						disk_bytenr, num_bytes, 0,
						root->root_key.objectid,
						new_key.objectid,
A
Arne Jansen 已提交
843
						start - extent_offset, 0);
844
				BUG_ON(ret); /* -ENOMEM */
845
			}
Y
Yan, Zheng 已提交
846
			key.offset = start;
Y
Yan Zheng 已提交
847
		}
Y
Yan, Zheng 已提交
848 849 850 851 852
		/*
		 *  | ---- range to drop ----- |
		 *      | -------- extent -------- |
		 */
		if (start <= key.offset && end < extent_end) {
853 854 855 856
			if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
				ret = -EINVAL;
				break;
			}
Y
Yan Zheng 已提交
857

Y
Yan, Zheng 已提交
858 859
			memcpy(&new_key, &key, sizeof(new_key));
			new_key.offset = end;
860
			btrfs_set_item_key_safe(root, path, &new_key);
Y
Yan Zheng 已提交
861

Y
Yan, Zheng 已提交
862 863 864 865 866
			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);
867
			if (update_refs && disk_bytenr > 0)
Y
Yan, Zheng 已提交
868 869
				inode_sub_bytes(inode, end - key.offset);
			break;
C
Chris Mason 已提交
870
		}
871

Y
Yan, Zheng 已提交
872 873 874 875 876 877 878
		search_start = extent_end;
		/*
		 *       | ---- range to drop ----- |
		 *  | -------- extent -------- |
		 */
		if (start > key.offset && end >= extent_end) {
			BUG_ON(del_nr > 0);
879 880 881 882
			if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
				ret = -EINVAL;
				break;
			}
883

Y
Yan, Zheng 已提交
884 885 886
			btrfs_set_file_extent_num_bytes(leaf, fi,
							start - key.offset);
			btrfs_mark_buffer_dirty(leaf);
887
			if (update_refs && disk_bytenr > 0)
Y
Yan, Zheng 已提交
888 889 890
				inode_sub_bytes(inode, extent_end - start);
			if (end == extent_end)
				break;
C
Chris Mason 已提交
891

Y
Yan, Zheng 已提交
892 893
			path->slots[0]++;
			goto next_slot;
Z
Zheng Yan 已提交
894 895
		}

Y
Yan, Zheng 已提交
896 897 898 899 900 901 902 903 904 905 906 907
		/*
		 *  | ---- range to drop ----- |
		 *    | ------ extent ------ |
		 */
		if (start <= key.offset && end >= extent_end) {
			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
908

J
Josef Bacik 已提交
909 910
			if (update_refs &&
			    extent_type == BTRFS_FILE_EXTENT_INLINE) {
911
				inode_sub_bytes(inode,
Y
Yan, Zheng 已提交
912 913 914
						extent_end - key.offset);
				extent_end = ALIGN(extent_end,
						   root->sectorsize);
J
Josef Bacik 已提交
915
			} else if (update_refs && disk_bytenr > 0) {
Z
Zheng Yan 已提交
916
				ret = btrfs_free_extent(trans, root,
Y
Yan, Zheng 已提交
917 918
						disk_bytenr, num_bytes, 0,
						root->root_key.objectid,
919
						key.objectid, key.offset -
A
Arne Jansen 已提交
920
						extent_offset, 0);
921
				BUG_ON(ret); /* -ENOMEM */
Y
Yan, Zheng 已提交
922 923
				inode_sub_bytes(inode,
						extent_end - key.offset);
Z
Zheng Yan 已提交
924 925
			}

Y
Yan, Zheng 已提交
926 927 928 929 930 931 932 933 934 935
			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);
936 937
			if (ret) {
				btrfs_abort_transaction(trans, root, ret);
J
Josef Bacik 已提交
938
				break;
939
			}
Y
Yan, Zheng 已提交
940 941 942 943

			del_nr = 0;
			del_slot = 0;

944
			btrfs_release_path(path);
Y
Yan, Zheng 已提交
945
			continue;
C
Chris Mason 已提交
946
		}
Y
Yan, Zheng 已提交
947 948

		BUG_ON(1);
C
Chris Mason 已提交
949
	}
Y
Yan, Zheng 已提交
950

951
	if (!ret && del_nr > 0) {
952 953 954 955
		/*
		 * 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
956
		 * path->slots[0] for our insertion (if replace_extent != 0).
957 958
		 */
		path->slots[0] = del_slot;
Y
Yan, Zheng 已提交
959
		ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
960 961
		if (ret)
			btrfs_abort_transaction(trans, root, ret);
962
	}
963

964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984
	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]++;
985
		}
986 987 988 989 990 991
		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
992
	}
Y
Yan, Zheng 已提交
993

994 995
	if (!replace_extent || !(*key_inserted))
		btrfs_release_path(path);
J
Josef Bacik 已提交
996
	if (drop_end)
997
		*drop_end = found ? min(end, extent_end) : end;
J
Josef Bacik 已提交
998 999 1000 1001 1002
	return ret;
}

int btrfs_drop_extents(struct btrfs_trans_handle *trans,
		       struct btrfs_root *root, struct inode *inode, u64 start,
1003
		       u64 end, int drop_cache)
J
Josef Bacik 已提交
1004 1005 1006 1007 1008 1009 1010
{
	struct btrfs_path *path;
	int ret;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;
J
Josef Bacik 已提交
1011
	ret = __btrfs_drop_extents(trans, root, inode, path, start, end, NULL,
1012
				   drop_cache, 0, 0, NULL);
Y
Yan, Zheng 已提交
1013
	btrfs_free_path(path);
C
Chris Mason 已提交
1014 1015 1016
	return ret;
}

Y
Yan Zheng 已提交
1017
static int extent_mergeable(struct extent_buffer *leaf, int slot,
1018 1019
			    u64 objectid, u64 bytenr, u64 orig_offset,
			    u64 *start, u64 *end)
Y
Yan Zheng 已提交
1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034
{
	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 ||
1035
	    btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
Y
Yan Zheng 已提交
1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059
	    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
1060
	struct btrfs_root *root = BTRFS_I(inode)->root;
Y
Yan Zheng 已提交
1061 1062 1063 1064
	struct extent_buffer *leaf;
	struct btrfs_path *path;
	struct btrfs_file_extent_item *fi;
	struct btrfs_key key;
Y
Yan, Zheng 已提交
1065
	struct btrfs_key new_key;
Y
Yan Zheng 已提交
1066 1067 1068
	u64 bytenr;
	u64 num_bytes;
	u64 extent_end;
1069
	u64 orig_offset;
Y
Yan Zheng 已提交
1070 1071
	u64 other_start;
	u64 other_end;
Y
Yan, Zheng 已提交
1072 1073 1074
	u64 split;
	int del_nr = 0;
	int del_slot = 0;
1075
	int recow;
Y
Yan Zheng 已提交
1076
	int ret;
L
Li Zefan 已提交
1077
	u64 ino = btrfs_ino(inode);
Y
Yan Zheng 已提交
1078 1079

	path = btrfs_alloc_path();
1080 1081
	if (!path)
		return -ENOMEM;
Y
Yan Zheng 已提交
1082
again:
1083
	recow = 0;
Y
Yan, Zheng 已提交
1084
	split = start;
L
Li Zefan 已提交
1085
	key.objectid = ino;
Y
Yan Zheng 已提交
1086
	key.type = BTRFS_EXTENT_DATA_KEY;
Y
Yan, Zheng 已提交
1087
	key.offset = split;
Y
Yan Zheng 已提交
1088 1089

	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1090 1091
	if (ret < 0)
		goto out;
Y
Yan Zheng 已提交
1092 1093 1094 1095 1096
	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
1097
	BUG_ON(key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY);
Y
Yan Zheng 已提交
1098 1099
	fi = btrfs_item_ptr(leaf, path->slots[0],
			    struct btrfs_file_extent_item);
Y
Yan, Zheng 已提交
1100 1101
	BUG_ON(btrfs_file_extent_type(leaf, fi) !=
	       BTRFS_FILE_EXTENT_PREALLOC);
Y
Yan Zheng 已提交
1102 1103 1104 1105 1106
	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);
1107
	orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
1108 1109 1110 1111 1112 1113
	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
1114
				     ino, bytenr, orig_offset,
1115 1116
				     &other_start, &other_end)) {
			new_key.offset = end;
1117
			btrfs_set_item_key_safe(root, path, &new_key);
1118 1119
			fi = btrfs_item_ptr(leaf, path->slots[0],
					    struct btrfs_file_extent_item);
1120 1121
			btrfs_set_file_extent_generation(leaf, fi,
							 trans->transid);
1122 1123 1124 1125 1126 1127
			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);
1128 1129
			btrfs_set_file_extent_generation(leaf, fi,
							 trans->transid);
1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140
			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
1141
				     ino, bytenr, orig_offset,
1142 1143 1144 1145 1146
				     &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);
1147 1148
			btrfs_set_file_extent_generation(leaf, fi,
							 trans->transid);
1149 1150
			path->slots[0]++;
			new_key.offset = start;
1151
			btrfs_set_item_key_safe(root, path, &new_key);
1152 1153 1154

			fi = btrfs_item_ptr(leaf, path->slots[0],
					    struct btrfs_file_extent_item);
1155 1156
			btrfs_set_file_extent_generation(leaf, fi,
							 trans->transid);
1157 1158 1159 1160 1161 1162 1163 1164
			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
1165

Y
Yan, Zheng 已提交
1166 1167 1168 1169 1170 1171 1172
	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) {
1173
			btrfs_release_path(path);
Y
Yan, Zheng 已提交
1174
			goto again;
Y
Yan Zheng 已提交
1175
		}
1176 1177 1178 1179
		if (ret < 0) {
			btrfs_abort_transaction(trans, root, ret);
			goto out;
		}
Y
Yan Zheng 已提交
1180

Y
Yan, Zheng 已提交
1181 1182
		leaf = path->nodes[0];
		fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
Y
Yan Zheng 已提交
1183
				    struct btrfs_file_extent_item);
1184
		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
Y
Yan Zheng 已提交
1185
		btrfs_set_file_extent_num_bytes(leaf, fi,
Y
Yan, Zheng 已提交
1186 1187 1188 1189 1190
						split - key.offset);

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

1191
		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
Y
Yan, Zheng 已提交
1192 1193 1194
		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
1195 1196
		btrfs_mark_buffer_dirty(leaf);

Y
Yan, Zheng 已提交
1197 1198
		ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
					   root->root_key.objectid,
A
Arne Jansen 已提交
1199
					   ino, orig_offset, 0);
1200
		BUG_ON(ret); /* -ENOMEM */
Y
Yan Zheng 已提交
1201

Y
Yan, Zheng 已提交
1202 1203 1204 1205
		if (split == start) {
			key.offset = start;
		} else {
			BUG_ON(start != key.offset);
Y
Yan Zheng 已提交
1206
			path->slots[0]--;
Y
Yan, Zheng 已提交
1207
			extent_end = end;
Y
Yan Zheng 已提交
1208
		}
1209
		recow = 1;
Y
Yan Zheng 已提交
1210 1211
	}

Y
Yan, Zheng 已提交
1212 1213
	other_start = end;
	other_end = 0;
1214
	if (extent_mergeable(leaf, path->slots[0] + 1,
L
Li Zefan 已提交
1215
			     ino, bytenr, orig_offset,
1216 1217
			     &other_start, &other_end)) {
		if (recow) {
1218
			btrfs_release_path(path);
1219 1220
			goto again;
		}
Y
Yan, Zheng 已提交
1221 1222 1223 1224 1225
		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,
A
Arne Jansen 已提交
1226
					ino, orig_offset, 0);
1227
		BUG_ON(ret); /* -ENOMEM */
Y
Yan Zheng 已提交
1228
	}
Y
Yan, Zheng 已提交
1229 1230
	other_start = 0;
	other_end = start;
1231
	if (extent_mergeable(leaf, path->slots[0] - 1,
L
Li Zefan 已提交
1232
			     ino, bytenr, orig_offset,
1233 1234
			     &other_start, &other_end)) {
		if (recow) {
1235
			btrfs_release_path(path);
1236 1237
			goto again;
		}
Y
Yan, Zheng 已提交
1238 1239 1240 1241 1242
		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,
A
Arne Jansen 已提交
1243
					ino, orig_offset, 0);
1244
		BUG_ON(ret); /* -ENOMEM */
Y
Yan, Zheng 已提交
1245 1246
	}
	if (del_nr == 0) {
1247 1248
		fi = btrfs_item_ptr(leaf, path->slots[0],
			   struct btrfs_file_extent_item);
Y
Yan, Zheng 已提交
1249 1250
		btrfs_set_file_extent_type(leaf, fi,
					   BTRFS_FILE_EXTENT_REG);
1251
		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
Y
Yan, Zheng 已提交
1252
		btrfs_mark_buffer_dirty(leaf);
1253
	} else {
1254 1255
		fi = btrfs_item_ptr(leaf, del_slot - 1,
			   struct btrfs_file_extent_item);
1256 1257
		btrfs_set_file_extent_type(leaf, fi,
					   BTRFS_FILE_EXTENT_REG);
1258
		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1259 1260 1261
		btrfs_set_file_extent_num_bytes(leaf, fi,
						extent_end - key.offset);
		btrfs_mark_buffer_dirty(leaf);
Y
Yan, Zheng 已提交
1262

1263
		ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
1264 1265 1266 1267
		if (ret < 0) {
			btrfs_abort_transaction(trans, root, ret);
			goto out;
		}
1268
	}
Y
Yan, Zheng 已提交
1269
out:
Y
Yan Zheng 已提交
1270 1271 1272 1273
	btrfs_free_path(path);
	return 0;
}

1274 1275 1276 1277
/*
 * on error we return an unlocked page and the error value
 * on success we return a locked page and 0
 */
1278 1279
static int prepare_uptodate_page(struct page *page, u64 pos,
				 bool force_uptodate)
1280 1281 1282
{
	int ret = 0;

1283 1284
	if (((pos & (PAGE_CACHE_SIZE - 1)) || force_uptodate) &&
	    !PageUptodate(page)) {
1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296
		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
1297
/*
1298
 * this just gets pages into the page cache and locks them down.
C
Chris Mason 已提交
1299
 */
1300 1301 1302
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
1303 1304 1305
{
	int i;
	unsigned long index = pos >> PAGE_CACHE_SHIFT;
1306
	gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1307
	int err = 0;
1308
	int faili;
1309

C
Chris Mason 已提交
1310
	for (i = 0; i < num_pages; i++) {
1311
		pages[i] = find_or_create_page(inode->i_mapping, index + i,
1312
					       mask | __GFP_WRITE);
C
Chris Mason 已提交
1313
		if (!pages[i]) {
1314 1315 1316 1317 1318 1319
			faili = i - 1;
			err = -ENOMEM;
			goto fail;
		}

		if (i == 0)
1320 1321
			err = prepare_uptodate_page(pages[i], pos,
						    force_uptodate);
1322 1323
		if (i == num_pages - 1)
			err = prepare_uptodate_page(pages[i],
1324
						    pos + write_bytes, false);
1325 1326 1327 1328
		if (err) {
			page_cache_release(pages[i]);
			faili = i - 1;
			goto fail;
C
Chris Mason 已提交
1329
		}
C
Chris Mason 已提交
1330
		wait_on_page_writeback(pages[i]);
C
Chris Mason 已提交
1331
	}
1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367

	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;

1368
	if (start_pos < inode->i_size) {
1369
		struct btrfs_ordered_extent *ordered;
1370
		lock_extent_bits(&BTRFS_I(inode)->io_tree,
1371
				 start_pos, last_pos, 0, cached_state);
1372 1373
		ordered = btrfs_lookup_ordered_range(inode, start_pos,
						     last_pos - start_pos + 1);
1374 1375
		if (ordered &&
		    ordered->file_offset + ordered->len > start_pos &&
1376
		    ordered->file_offset <= last_pos) {
1377
			unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1378 1379
					     start_pos, last_pos,
					     cached_state, GFP_NOFS);
1380 1381 1382 1383
			for (i = 0; i < num_pages; i++) {
				unlock_page(pages[i]);
				page_cache_release(pages[i]);
			}
1384 1385 1386
			btrfs_start_ordered_extent(inode, ordered, 1);
			btrfs_put_ordered_extent(ordered);
			return -EAGAIN;
1387 1388 1389 1390
		}
		if (ordered)
			btrfs_put_ordered_extent(ordered);

1391
		clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
1392
				  last_pos, EXTENT_DIRTY | EXTENT_DELALLOC |
1393
				  EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
1394 1395 1396 1397
				  0, 0, cached_state, GFP_NOFS);
		*lockstart = start_pos;
		*lockend = last_pos;
		ret = 1;
1398
	}
1399

1400
	for (i = 0; i < num_pages; i++) {
1401 1402
		if (clear_page_dirty_for_io(pages[i]))
			account_page_redirty(pages[i]);
1403 1404 1405
		set_page_extent_mapped(pages[i]);
		WARN_ON(!PageLocked(pages[i]));
	}
1406

1407
	return ret;
C
Chris Mason 已提交
1408 1409
}

1410 1411 1412 1413 1414 1415 1416 1417 1418
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;

1419 1420 1421 1422
	ret = btrfs_start_nocow_write(root);
	if (!ret)
		return -ENOSPC;

1423
	lockstart = round_down(pos, root->sectorsize);
1424
	lockend = round_up(pos + *write_bytes, root->sectorsize) - 1;
1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438

	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;
1439
	ret = can_nocow_extent(inode, lockstart, &num_bytes, NULL, NULL, NULL);
1440
	if (ret <= 0) {
1441
		ret = 0;
1442 1443
		btrfs_end_nocow_write(root);
	} else {
1444 1445
		*write_bytes = min_t(size_t, *write_bytes ,
				     num_bytes - pos + lockstart);
1446
	}
1447 1448 1449 1450 1451 1452

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

	return ret;
}

J
Josef Bacik 已提交
1453 1454 1455
static noinline ssize_t __btrfs_buffered_write(struct file *file,
					       struct iov_iter *i,
					       loff_t pos)
1456
{
A
Al Viro 已提交
1457
	struct inode *inode = file_inode(file);
1458 1459
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct page **pages = NULL;
1460
	struct extent_state *cached_state = NULL;
1461
	u64 release_bytes = 0;
1462 1463
	u64 lockstart;
	u64 lockend;
C
Chris Mason 已提交
1464
	unsigned long first_index;
J
Josef Bacik 已提交
1465 1466
	size_t num_written = 0;
	int nrptrs;
1467
	int ret = 0;
1468
	bool only_release_metadata = false;
1469
	bool force_page_uptodate = false;
1470
	bool need_unlock;
1471

J
Josef Bacik 已提交
1472
	nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
1473 1474
		     PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
		     (sizeof(struct page *)));
1475 1476
	nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
	nrptrs = max(nrptrs, 8);
1477
	pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
J
Josef Bacik 已提交
1478 1479
	if (!pages)
		return -ENOMEM;
1480

C
Chris Mason 已提交
1481 1482
	first_index = pos >> PAGE_CACHE_SHIFT;

J
Josef Bacik 已提交
1483
	while (iov_iter_count(i) > 0) {
C
Chris Mason 已提交
1484
		size_t offset = pos & (PAGE_CACHE_SIZE - 1);
J
Josef Bacik 已提交
1485
		size_t write_bytes = min(iov_iter_count(i),
1486
					 nrptrs * (size_t)PAGE_CACHE_SIZE -
1487
					 offset);
Y
Yan, Zheng 已提交
1488 1489
		size_t num_pages = (write_bytes + offset +
				    PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1490
		size_t reserve_bytes;
J
Josef Bacik 已提交
1491 1492
		size_t dirty_pages;
		size_t copied;
C
Chris Mason 已提交
1493

1494
		WARN_ON(num_pages > nrptrs);
1495

1496 1497 1498 1499
		/*
		 * Fault pages before locking them in prepare_pages
		 * to avoid recursive lock
		 */
J
Josef Bacik 已提交
1500
		if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
1501
			ret = -EFAULT;
J
Josef Bacik 已提交
1502
			break;
1503 1504
		}

1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526
		reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
		ret = btrfs_check_data_free_space(inode, reserve_bytes);
		if (ret == -ENOSPC &&
		    (BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW |
					      BTRFS_INODE_PREALLOC))) {
			ret = check_can_nocow(inode, pos, &write_bytes);
			if (ret > 0) {
				only_release_metadata = true;
				/*
				 * our prealloc extent may be smaller than
				 * write_bytes, so scale down.
				 */
				num_pages = (write_bytes + offset +
					     PAGE_CACHE_SIZE - 1) >>
					PAGE_CACHE_SHIFT;
				reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
				ret = 0;
			} else {
				ret = -ENOSPC;
			}
		}

1527
		if (ret)
J
Josef Bacik 已提交
1528
			break;
1529

1530 1531 1532 1533 1534
		ret = btrfs_delalloc_reserve_metadata(inode, reserve_bytes);
		if (ret) {
			if (!only_release_metadata)
				btrfs_free_reserved_data_space(inode,
							       reserve_bytes);
1535 1536
			else
				btrfs_end_nocow_write(root);
1537 1538 1539 1540
			break;
		}

		release_bytes = reserve_bytes;
1541 1542
		need_unlock = false;
again:
1543 1544 1545 1546 1547
		/*
		 * 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
		 */
1548 1549
		ret = prepare_pages(inode, pages, num_pages,
				    pos, write_bytes,
1550
				    force_page_uptodate);
1551
		if (ret)
J
Josef Bacik 已提交
1552
			break;
C
Chris Mason 已提交
1553

1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565
		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;
		}

1566
		copied = btrfs_copy_from_user(pos, num_pages,
J
Josef Bacik 已提交
1567
					   write_bytes, pages, i);
1568 1569 1570 1571 1572 1573 1574 1575

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

1576 1577
		if (copied == 0) {
			force_page_uptodate = true;
1578
			dirty_pages = 0;
1579 1580
		} else {
			force_page_uptodate = false;
1581 1582 1583
			dirty_pages = (copied + offset +
				       PAGE_CACHE_SIZE - 1) >>
				       PAGE_CACHE_SHIFT;
1584
		}
1585

J
Josef Bacik 已提交
1586 1587 1588 1589 1590 1591 1592
		/*
		 * 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.
		 */
1593
		if (num_pages > dirty_pages) {
1594 1595
			release_bytes = (num_pages - dirty_pages) <<
				PAGE_CACHE_SHIFT;
1596 1597 1598 1599 1600
			if (copied > 0) {
				spin_lock(&BTRFS_I(inode)->lock);
				BTRFS_I(inode)->outstanding_extents++;
				spin_unlock(&BTRFS_I(inode)->lock);
			}
1601 1602 1603 1604 1605 1606
			if (only_release_metadata)
				btrfs_delalloc_release_metadata(inode,
								release_bytes);
			else
				btrfs_delalloc_release_space(inode,
							     release_bytes);
1607 1608
		}

1609
		release_bytes = dirty_pages << PAGE_CACHE_SHIFT;
1610 1611

		if (copied > 0)
1612 1613 1614
			ret = btrfs_dirty_pages(root, inode, pages,
						dirty_pages, pos, copied,
						NULL);
1615 1616 1617 1618
		if (need_unlock)
			unlock_extent_cached(&BTRFS_I(inode)->io_tree,
					     lockstart, lockend, &cached_state,
					     GFP_NOFS);
1619 1620
		if (ret) {
			btrfs_drop_pages(pages, num_pages);
1621
			break;
1622
		}
C
Chris Mason 已提交
1623

1624
		release_bytes = 0;
1625 1626 1627
		if (only_release_metadata)
			btrfs_end_nocow_write(root);

1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638
		if (only_release_metadata && copied > 0) {
			u64 lockstart = round_down(pos, root->sectorsize);
			u64 lockend = lockstart +
				(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;
		}

1639 1640
		btrfs_drop_pages(pages, num_pages);

J
Josef Bacik 已提交
1641 1642
		cond_resched();

1643
		balance_dirty_pages_ratelimited(inode->i_mapping);
J
Josef Bacik 已提交
1644
		if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1645
			btrfs_btree_balance_dirty(root);
1646

1647 1648
		pos += copied;
		num_written += copied;
J
Josef Bacik 已提交
1649
	}
C
Chris Mason 已提交
1650

J
Josef Bacik 已提交
1651 1652
	kfree(pages);

1653
	if (release_bytes) {
1654 1655
		if (only_release_metadata) {
			btrfs_end_nocow_write(root);
1656
			btrfs_delalloc_release_metadata(inode, release_bytes);
1657
		} else {
1658
			btrfs_delalloc_release_space(inode, release_bytes);
1659
		}
1660 1661
	}

J
Josef Bacik 已提交
1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689
	return num_written ? num_written : ret;
}

static ssize_t __btrfs_direct_write(struct kiocb *iocb,
				    const struct iovec *iov,
				    unsigned long nr_segs, loff_t pos,
				    loff_t *ppos, size_t count, size_t ocount)
{
	struct file *file = iocb->ki_filp;
	struct iov_iter i;
	ssize_t written;
	ssize_t written_buffered;
	loff_t endbyte;
	int err;

	written = generic_file_direct_write(iocb, iov, &nr_segs, pos, ppos,
					    count, ocount);

	if (written < 0 || written == count)
		return written;

	pos += written;
	count -= written;
	iov_iter_init(&i, iov, nr_segs, count, written);
	written_buffered = __btrfs_buffered_write(file, &i, pos);
	if (written_buffered < 0) {
		err = written_buffered;
		goto out;
C
Chris Mason 已提交
1690
	}
J
Josef Bacik 已提交
1691 1692 1693 1694 1695 1696 1697 1698
	endbyte = pos + written_buffered - 1;
	err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
	if (err)
		goto out;
	written += written_buffered;
	*ppos = pos + written_buffered;
	invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT,
				 endbyte >> PAGE_CACHE_SHIFT);
C
Chris Mason 已提交
1699
out:
J
Josef Bacik 已提交
1700 1701
	return written ? written : err;
}
1702

1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720
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);
}

J
Josef Bacik 已提交
1721 1722 1723 1724 1725
static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
				    const struct iovec *iov,
				    unsigned long nr_segs, loff_t pos)
{
	struct file *file = iocb->ki_filp;
A
Al Viro 已提交
1726
	struct inode *inode = file_inode(file);
J
Josef Bacik 已提交
1727 1728
	struct btrfs_root *root = BTRFS_I(inode)->root;
	loff_t *ppos = &iocb->ki_pos;
1729
	u64 start_pos;
1730
	u64 end_pos;
J
Josef Bacik 已提交
1731 1732 1733
	ssize_t num_written = 0;
	ssize_t err = 0;
	size_t count, ocount;
1734
	bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host);
J
Josef Bacik 已提交
1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768

	mutex_lock(&inode->i_mutex);

	err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
	if (err) {
		mutex_unlock(&inode->i_mutex);
		goto out;
	}
	count = ocount;

	current->backing_dev_info = inode->i_mapping->backing_dev_info;
	err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
	if (err) {
		mutex_unlock(&inode->i_mutex);
		goto out;
	}

	if (count == 0) {
		mutex_unlock(&inode->i_mutex);
		goto out;
	}

	err = file_remove_suid(file);
	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.
	 */
1769
	if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
J
Josef Bacik 已提交
1770 1771 1772 1773 1774
		mutex_unlock(&inode->i_mutex);
		err = -EROFS;
		goto out;
	}

1775 1776 1777 1778 1779 1780 1781
	/*
	 * 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
1782

1783 1784
	start_pos = round_down(pos, root->sectorsize);
	if (start_pos > i_size_read(inode)) {
1785 1786 1787
		/* Expand hole size to cover write data, preventing empty gap */
		end_pos = round_up(pos + iov->iov_len, root->sectorsize);
		err = btrfs_cont_expand(inode, i_size_read(inode), end_pos);
1788 1789 1790 1791 1792 1793
		if (err) {
			mutex_unlock(&inode->i_mutex);
			goto out;
		}
	}

1794 1795 1796
	if (sync)
		atomic_inc(&BTRFS_I(inode)->sync_writers);

J
Josef Bacik 已提交
1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810
	if (unlikely(file->f_flags & O_DIRECT)) {
		num_written = __btrfs_direct_write(iocb, iov, nr_segs,
						   pos, ppos, count, ocount);
	} else {
		struct iov_iter i;

		iov_iter_init(&i, iov, nr_segs, count, num_written);

		num_written = __btrfs_buffered_write(file, &i, pos);
		if (num_written > 0)
			*ppos = pos + num_written;
	}

	mutex_unlock(&inode->i_mutex);
1811

1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822
	/*
	 * we want to make sure fsync finds this change
	 * but we haven't joined a transaction running right now.
	 *
	 * Later on, someone is sure to update the inode and get the
	 * real transid recorded.
	 *
	 * We set last_trans now to the fs_info generation + 1,
	 * this will either be one more than the running transaction
	 * or the generation used for the next transaction if there isn't
	 * one running right now.
1823 1824 1825 1826
	 *
	 * 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.
1827 1828
	 */
	BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1829
	BTRFS_I(inode)->last_sub_trans = root->log_transid;
1830
	if (num_written > 0) {
J
Josef Bacik 已提交
1831 1832
		err = generic_write_sync(file, pos, num_written);
		if (err < 0 && num_written > 0)
1833 1834
			num_written = err;
	}
1835

1836 1837
	if (sync)
		atomic_dec(&BTRFS_I(inode)->sync_writers);
1838
out:
C
Chris Mason 已提交
1839 1840 1841 1842
	current->backing_dev_info = NULL;
	return num_written ? num_written : err;
}

C
Chris Mason 已提交
1843
int btrfs_release_file(struct inode *inode, struct file *filp)
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.
	 */
1851 1852
	if (test_and_clear_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
			       &BTRFS_I(inode)->runtime_flags)) {
1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866
		struct btrfs_trans_handle *trans;
		struct btrfs_root *root = BTRFS_I(inode)->root;

		/*
		 * We need to block on a committing transaction to keep us from
		 * throwing a ordered operation on to the list and causing
		 * something like sync to deadlock trying to flush out this
		 * inode.
		 */
		trans = btrfs_start_transaction(root, 0);
		if (IS_ERR(trans))
			return PTR_ERR(trans);
		btrfs_add_ordered_operation(trans, BTRFS_I(inode)->root, inode);
		btrfs_end_transaction(trans, root);
1867 1868 1869
		if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
			filemap_flush(inode->i_mapping);
	}
S
Sage Weil 已提交
1870 1871
	if (filp->private_data)
		btrfs_ioctl_trans_end(filp);
1872 1873 1874
	return 0;
}

C
Chris Mason 已提交
1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885
/*
 * 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.
 */
1886
int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
C
Chris Mason 已提交
1887
{
1888
	struct dentry *dentry = file->f_path.dentry;
C
Chris Mason 已提交
1889 1890 1891
	struct inode *inode = dentry->d_inode;
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct btrfs_trans_handle *trans;
1892 1893
	struct btrfs_log_ctx ctx;
	int ret = 0;
1894
	bool full_sync = 0;
C
Chris Mason 已提交
1895

1896
	trace_btrfs_sync_file(file, datasync);
1897

1898 1899 1900
	/*
	 * 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
1901 1902
	 * multi-task, and make the performance up.  See
	 * btrfs_wait_ordered_range for an explanation of the ASYNC check.
1903
	 */
1904
	atomic_inc(&BTRFS_I(inode)->sync_writers);
1905 1906 1907 1908
	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);
1909
	atomic_dec(&BTRFS_I(inode)->sync_writers);
1910 1911 1912
	if (ret)
		return ret;

1913 1914
	mutex_lock(&inode->i_mutex);

1915
	/*
1916 1917
	 * We flush the dirty pages again to avoid some dirty pages in the
	 * range being left.
1918
	 */
M
Miao Xie 已提交
1919
	atomic_inc(&root->log_batch);
1920 1921
	full_sync = test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
			     &BTRFS_I(inode)->runtime_flags);
1922 1923 1924 1925 1926 1927 1928
	if (full_sync) {
		ret = btrfs_wait_ordered_range(inode, start, end - start + 1);
		if (ret) {
			mutex_unlock(&inode->i_mutex);
			goto out;
		}
	}
M
Miao Xie 已提交
1929
	atomic_inc(&root->log_batch);
1930

C
Chris Mason 已提交
1931
	/*
1932 1933
	 * check the transaction that last modified this inode
	 * and see if its already been committed
C
Chris Mason 已提交
1934
	 */
1935 1936
	if (!BTRFS_I(inode)->last_trans) {
		mutex_unlock(&inode->i_mutex);
1937
		goto out;
1938
	}
1939

1940 1941 1942 1943 1944
	/*
	 * if the last transaction that changed this file was before
	 * the current transaction, we can bail out now without any
	 * syncing
	 */
J
Josef Bacik 已提交
1945
	smp_mb();
1946 1947
	if (btrfs_inode_in_log(inode, root->fs_info->generation) ||
	    BTRFS_I(inode)->last_trans <=
1948 1949
	    root->fs_info->last_trans_committed) {
		BTRFS_I(inode)->last_trans = 0;
J
Josef Bacik 已提交
1950 1951 1952 1953 1954 1955 1956 1957

		/*
		 * 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);
1958
		mutex_unlock(&inode->i_mutex);
1959 1960 1961 1962
		goto out;
	}

	/*
1963 1964
	 * ok we haven't committed the transaction yet, lets do a commit
	 */
1965
	if (file->private_data)
S
Sage Weil 已提交
1966 1967
		btrfs_ioctl_trans_end(file);

1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978
	/*
	 * 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*.
	 */
1979 1980 1981
	trans = btrfs_start_transaction(root, 0);
	if (IS_ERR(trans)) {
		ret = PTR_ERR(trans);
1982
		mutex_unlock(&inode->i_mutex);
C
Chris Mason 已提交
1983 1984
		goto out;
	}
1985
	trans->sync = true;
1986

1987 1988 1989
	btrfs_init_log_ctx(&ctx);

	ret = btrfs_log_dentry_safe(trans, root, dentry, &ctx);
1990
	if (ret < 0) {
1991 1992
		/* Fallthrough and commit/free transaction. */
		ret = 1;
1993
	}
C
Chris Mason 已提交
1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

	/* 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.
	 */
2005
	mutex_unlock(&inode->i_mutex);
C
Chris Mason 已提交
2006

2007
	if (ret != BTRFS_NO_LOG_SYNC) {
2008
		if (!ret) {
2009
			ret = btrfs_sync_log(trans, root, &ctx);
2010
			if (!ret) {
2011
				ret = btrfs_end_transaction(trans, root);
2012
				goto out;
2013
			}
2014
		}
2015 2016 2017 2018 2019 2020 2021
		if (!full_sync) {
			ret = btrfs_wait_ordered_range(inode, start,
						       end - start + 1);
			if (ret)
				goto out;
		}
		ret = btrfs_commit_transaction(trans, root);
2022 2023
	} else {
		ret = btrfs_end_transaction(trans, root);
2024
	}
C
Chris Mason 已提交
2025
out:
2026
	return ret > 0 ? -EIO : ret;
C
Chris Mason 已提交
2027 2028
}

2029
static const struct vm_operations_struct btrfs_file_vm_ops = {
2030
	.fault		= filemap_fault,
C
Chris Mason 已提交
2031
	.page_mkwrite	= btrfs_page_mkwrite,
2032
	.remap_pages	= generic_file_remap_pages,
C
Chris Mason 已提交
2033 2034 2035 2036
};

static int btrfs_file_mmap(struct file	*filp, struct vm_area_struct *vma)
{
M
Miao Xie 已提交
2037 2038 2039 2040 2041
	struct address_space *mapping = filp->f_mapping;

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

C
Chris Mason 已提交
2042
	file_accessed(filp);
M
Miao Xie 已提交
2043 2044
	vma->vm_ops = &btrfs_file_vm_ops;

C
Chris Mason 已提交
2045 2046 2047
	return 0;
}

J
Josef Bacik 已提交
2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087
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;

2088 2089 2090
	if (btrfs_fs_incompat(root->fs_info, NO_HOLES))
		goto out;

J
Josef Bacik 已提交
2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120
	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;
	}

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

		path->slots[0]++;
		key.offset = offset;
2121
		btrfs_set_item_key_safe(root, path, &key);
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Josef Bacik 已提交
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
		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
2151
		hole_em->ram_bytes = hole_em->len;
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Josef Bacik 已提交
2152 2153 2154 2155
		hole_em->orig_start = offset;

		hole_em->block_start = EXTENT_MAP_HOLE;
		hole_em->block_len = 0;
2156
		hole_em->orig_block_len = 0;
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Josef Bacik 已提交
2157 2158 2159 2160 2161 2162 2163
		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
2164
			ret = add_extent_mapping(em_tree, hole_em, 1);
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Josef Bacik 已提交
2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182
			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;
}

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;
M
Miao Xie 已提交
2183 2184 2185
	u64 lockstart = round_up(offset, BTRFS_I(inode)->root->sectorsize);
	u64 lockend = round_down(offset + len,
				 BTRFS_I(inode)->root->sectorsize) - 1;
J
Josef Bacik 已提交
2186 2187 2188 2189 2190
	u64 cur_offset = lockstart;
	u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
	u64 drop_end;
	int ret = 0;
	int err = 0;
2191
	int rsv_count;
2192 2193
	bool same_page = ((offset >> PAGE_CACHE_SHIFT) ==
			  ((offset + len - 1) >> PAGE_CACHE_SHIFT));
2194
	bool no_holes = btrfs_fs_incompat(root->fs_info, NO_HOLES);
2195
	u64 ino_size = round_up(inode->i_size, PAGE_CACHE_SIZE);
J
Josef Bacik 已提交
2196

2197 2198 2199
	ret = btrfs_wait_ordered_range(inode, offset, len);
	if (ret)
		return ret;
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Josef Bacik 已提交
2200 2201

	mutex_lock(&inode->i_mutex);
2202 2203 2204 2205
	/*
	 * We needn't truncate any page which is beyond the end of the file
	 * because we are sure there is no data there.
	 */
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Josef Bacik 已提交
2206 2207 2208 2209 2210
	/*
	 * 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) {
2211
		if (offset < ino_size)
2212
			ret = btrfs_truncate_page(inode, offset, len, 0);
J
Josef Bacik 已提交
2213 2214 2215 2216 2217
		mutex_unlock(&inode->i_mutex);
		return ret;
	}

	/* zero back part of the first page */
2218
	if (offset < ino_size) {
2219 2220 2221 2222 2223
		ret = btrfs_truncate_page(inode, offset, 0, 0);
		if (ret) {
			mutex_unlock(&inode->i_mutex);
			return ret;
		}
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Josef Bacik 已提交
2224 2225 2226
	}

	/* zero the front end of the last page */
2227
	if (offset + len < ino_size) {
M
Miao Xie 已提交
2228 2229 2230 2231 2232
		ret = btrfs_truncate_page(inode, offset + len, 0, 1);
		if (ret) {
			mutex_unlock(&inode->i_mutex);
			return ret;
		}
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Josef Bacik 已提交
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	}

	if (lockend < lockstart) {
		mutex_unlock(&inode->i_mutex);
		return 0;
	}

	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 ||
2255
		    (ordered->file_offset + ordered->len <= lockstart ||
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Josef Bacik 已提交
2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267
		     ordered->file_offset > lockend)) &&
		     !test_range_bit(&BTRFS_I(inode)->io_tree, lockstart,
				     lockend, EXTENT_UPTODATE, 0,
				     cached_state)) {
			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);
2268 2269 2270 2271 2272 2273
		ret = btrfs_wait_ordered_range(inode, lockstart,
					       lockend - lockstart + 1);
		if (ret) {
			mutex_unlock(&inode->i_mutex);
			return ret;
		}
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Josef Bacik 已提交
2274 2275 2276 2277 2278 2279 2280 2281
	}

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

2282
	rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
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Josef Bacik 已提交
2283 2284 2285 2286 2287 2288 2289 2290 2291 2292
	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
2293
	 * 1 - adding the hole extent if no_holes isn't set
J
Josef Bacik 已提交
2294
	 */
2295 2296
	rsv_count = no_holes ? 2 : 3;
	trans = btrfs_start_transaction(root, rsv_count);
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Josef Bacik 已提交
2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309
	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;

	while (cur_offset < lockend) {
		ret = __btrfs_drop_extents(trans, root, inode, path,
					   cur_offset, lockend + 1,
2310
					   &drop_end, 1, 0, 0, NULL);
J
Josef Bacik 已提交
2311 2312 2313 2314 2315
		if (ret != -ENOSPC)
			break;

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

2316 2317 2318 2319 2320 2321 2322
		if (cur_offset < ino_size) {
			ret = fill_holes(trans, inode, path, cur_offset,
					 drop_end);
			if (ret) {
				err = ret;
				break;
			}
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Josef Bacik 已提交
2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333
		}

		cur_offset = drop_end;

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

		btrfs_end_transaction(trans, root);
2334
		btrfs_btree_balance_dirty(root);
J
Josef Bacik 已提交
2335

2336
		trans = btrfs_start_transaction(root, rsv_count);
J
Josef Bacik 已提交
2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354
		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;
	}

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

	trans->block_rsv = &root->fs_info->trans_block_rsv;
2355 2356 2357 2358 2359 2360
	if (cur_offset < ino_size) {
		ret = fill_holes(trans, inode, path, cur_offset, drop_end);
		if (ret) {
			err = ret;
			goto out_trans;
		}
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Josef Bacik 已提交
2361 2362 2363 2364 2365 2366
	}

out_trans:
	if (!trans)
		goto out_free;

2367 2368 2369
	inode_inc_iversion(inode);
	inode->i_mtime = inode->i_ctime = CURRENT_TIME;

J
Josef Bacik 已提交
2370 2371 2372
	trans->block_rsv = &root->fs_info->trans_block_rsv;
	ret = btrfs_update_inode(trans, root, inode);
	btrfs_end_transaction(trans, root);
2373
	btrfs_btree_balance_dirty(root);
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Josef Bacik 已提交
2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385
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);
	mutex_unlock(&inode->i_mutex);
	if (ret && !err)
		err = ret;
	return err;
}

2386 2387 2388
static long btrfs_fallocate(struct file *file, int mode,
			    loff_t offset, loff_t len)
{
A
Al Viro 已提交
2389
	struct inode *inode = file_inode(file);
2390
	struct extent_state *cached_state = NULL;
2391
	struct btrfs_root *root = BTRFS_I(inode)->root;
2392 2393 2394 2395 2396 2397 2398
	u64 cur_offset;
	u64 last_byte;
	u64 alloc_start;
	u64 alloc_end;
	u64 alloc_hint = 0;
	u64 locked_end;
	struct extent_map *em;
2399
	int blocksize = BTRFS_I(inode)->root->sectorsize;
2400 2401
	int ret;

2402 2403
	alloc_start = round_down(offset, blocksize);
	alloc_end = round_up(offset + len, blocksize);
2404

J
Josef Bacik 已提交
2405 2406
	/* Make sure we aren't being give some crap mode */
	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
2407 2408
		return -EOPNOTSUPP;

J
Josef Bacik 已提交
2409 2410 2411
	if (mode & FALLOC_FL_PUNCH_HOLE)
		return btrfs_punch_hole(inode, offset, len);

2412 2413 2414 2415
	/*
	 * Make sure we have enough space before we do the
	 * allocation.
	 */
2416
	ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start);
2417 2418
	if (ret)
		return ret;
2419 2420 2421 2422 2423
	if (root->fs_info->quota_enabled) {
		ret = btrfs_qgroup_reserve(root, alloc_end - alloc_start);
		if (ret)
			goto out_reserve_fail;
	}
2424

2425 2426 2427 2428 2429 2430
	mutex_lock(&inode->i_mutex);
	ret = inode_newsize_ok(inode, alloc_end);
	if (ret)
		goto out;

	if (alloc_start > inode->i_size) {
2431 2432
		ret = btrfs_cont_expand(inode, i_size_read(inode),
					alloc_start);
2433 2434
		if (ret)
			goto out;
2435 2436 2437 2438 2439 2440 2441 2442 2443
	} else {
		/*
		 * 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;
2444 2445
	}

2446 2447 2448 2449
	/*
	 * wait for ordered IO before we have any locks.  We'll loop again
	 * below with the locks held.
	 */
2450 2451 2452 2453
	ret = btrfs_wait_ordered_range(inode, alloc_start,
				       alloc_end - alloc_start);
	if (ret)
		goto out;
2454

2455 2456 2457 2458 2459 2460 2461 2462
	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,
2463
				 locked_end, 0, &cached_state);
2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476
		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
			 */
2477 2478 2479 2480
			ret = btrfs_wait_ordered_range(inode, alloc_start,
						       alloc_end - alloc_start);
			if (ret)
				goto out;
2481 2482 2483 2484 2485 2486 2487 2488 2489
		} else {
			if (ordered)
				btrfs_put_ordered_extent(ordered);
			break;
		}
	}

	cur_offset = alloc_start;
	while (1) {
2490 2491
		u64 actual_end;

2492 2493
		em = btrfs_get_extent(inode, NULL, 0, cur_offset,
				      alloc_end - cur_offset, 0);
2494 2495 2496 2497 2498 2499 2500
		if (IS_ERR_OR_NULL(em)) {
			if (!em)
				ret = -ENOMEM;
			else
				ret = PTR_ERR(em);
			break;
		}
2501
		last_byte = min(extent_map_end(em), alloc_end);
2502
		actual_end = min_t(u64, extent_map_end(em), offset + len);
2503
		last_byte = ALIGN(last_byte, blocksize);
2504

2505 2506 2507 2508 2509 2510 2511 2512
		if (em->block_start == EXTENT_MAP_HOLE ||
		    (cur_offset >= inode->i_size &&
		     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
			ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
							last_byte - cur_offset,
							1 << inode->i_blkbits,
							offset + len,
							&alloc_hint);
2513

2514 2515 2516 2517
			if (ret < 0) {
				free_extent_map(em);
				break;
			}
2518 2519 2520 2521 2522 2523 2524 2525 2526 2527
		} else if (actual_end > inode->i_size &&
			   !(mode & FALLOC_FL_KEEP_SIZE)) {
			/*
			 * 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.
			 */
			inode->i_ctime = CURRENT_TIME;
			i_size_write(inode, actual_end);
			btrfs_ordered_update_i_size(inode, actual_end, NULL);
2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540
		}
		free_extent_map(em);

		cur_offset = last_byte;
		if (cur_offset >= alloc_end) {
			ret = 0;
			break;
		}
	}
	unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
			     &cached_state, GFP_NOFS);
out:
	mutex_unlock(&inode->i_mutex);
2541 2542 2543
	if (root->fs_info->quota_enabled)
		btrfs_qgroup_free(root, alloc_end - alloc_start);
out_reserve_fail:
2544
	/* Let go of our reservation. */
2545
	btrfs_free_reserved_data_space(inode, alloc_end - alloc_start);
2546 2547 2548
	return ret;
}

2549
static int find_desired_extent(struct inode *inode, loff_t *offset, int whence)
J
Josef Bacik 已提交
2550 2551
{
	struct btrfs_root *root = BTRFS_I(inode)->root;
2552
	struct extent_map *em = NULL;
J
Josef Bacik 已提交
2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563
	struct extent_state *cached_state = NULL;
	u64 lockstart = *offset;
	u64 lockend = i_size_read(inode);
	u64 start = *offset;
	u64 len = i_size_read(inode);
	int ret = 0;

	lockend = max_t(u64, root->sectorsize, lockend);
	if (lockend <= lockstart)
		lockend = lockstart + root->sectorsize;

L
Liu Bo 已提交
2564
	lockend--;
J
Josef Bacik 已提交
2565 2566 2567 2568 2569 2570 2571
	len = lockend - lockstart + 1;

	len = max_t(u64, len, root->sectorsize);
	if (inode->i_size == 0)
		return -ENXIO;

	lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend, 0,
2572
			 &cached_state);
J
Josef Bacik 已提交
2573

2574
	while (start < inode->i_size) {
J
Josef Bacik 已提交
2575 2576
		em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0);
		if (IS_ERR(em)) {
2577
			ret = PTR_ERR(em);
2578
			em = NULL;
J
Josef Bacik 已提交
2579 2580 2581
			break;
		}

2582 2583 2584 2585 2586 2587 2588 2589
		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
2590 2591 2592

		start = em->start + em->len;
		free_extent_map(em);
2593
		em = NULL;
J
Josef Bacik 已提交
2594 2595
		cond_resched();
	}
2596 2597 2598 2599 2600 2601 2602
	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
2603 2604 2605 2606 2607
	unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
			     &cached_state, GFP_NOFS);
	return ret;
}

2608
static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
J
Josef Bacik 已提交
2609 2610 2611 2612 2613
{
	struct inode *inode = file->f_mapping->host;
	int ret;

	mutex_lock(&inode->i_mutex);
2614
	switch (whence) {
J
Josef Bacik 已提交
2615 2616
	case SEEK_END:
	case SEEK_CUR:
2617
		offset = generic_file_llseek(file, offset, whence);
J
Josef Bacik 已提交
2618 2619 2620
		goto out;
	case SEEK_DATA:
	case SEEK_HOLE:
2621 2622 2623 2624 2625
		if (offset >= i_size_read(inode)) {
			mutex_unlock(&inode->i_mutex);
			return -ENXIO;
		}

2626
		ret = find_desired_extent(inode, &offset, whence);
J
Josef Bacik 已提交
2627 2628 2629 2630 2631 2632
		if (ret) {
			mutex_unlock(&inode->i_mutex);
			return ret;
		}
	}

J
Jie Liu 已提交
2633
	offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
J
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out:
	mutex_unlock(&inode->i_mutex);
	return offset;
}

2639
const struct file_operations btrfs_file_operations = {
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	.llseek		= btrfs_file_llseek,
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	.read		= do_sync_read,
2642
	.write		= do_sync_write,
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	.aio_read       = generic_file_aio_read,
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	.splice_read	= generic_file_splice_read,
2645
	.aio_write	= btrfs_file_aio_write,
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2646
	.mmap		= btrfs_file_mmap,
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	.open		= generic_file_open,
2648
	.release	= btrfs_release_file,
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	.fsync		= btrfs_sync_file,
2650
	.fallocate	= btrfs_fallocate,
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2651
	.unlocked_ioctl	= btrfs_ioctl,
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#ifdef CONFIG_COMPAT
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	.compat_ioctl	= btrfs_ioctl,
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#endif
};
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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;
}