file.c 63.6 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 "compat.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;
	}
	if (btrfs_root_refs(&inode_root->root_item) == 0) {
		ret = -ENOENT;
		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);
	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;
582
		if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
583
			if (testend && em->start + em->len >= start + len) {
584
				free_extent_map(em);
C
Chris Mason 已提交
585
				write_unlock(&em_tree->lock);
586 587
				break;
			}
588 589
			start = em->start + em->len;
			if (testend)
590 591
				len = start + len - (em->start + em->len);
			free_extent_map(em);
C
Chris Mason 已提交
592
			write_unlock(&em_tree->lock);
593 594
			continue;
		}
C
Chris Mason 已提交
595
		compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
596
		clear_bit(EXTENT_FLAG_PINNED, &em->flags);
L
Liu Bo 已提交
597
		clear_bit(EXTENT_FLAG_LOGGING, &flags);
J
Josef Bacik 已提交
598
		modified = !list_empty(&em->list);
599
		remove_extent_mapping(em_tree, em);
600 601
		if (no_splits)
			goto next;
602 603 604 605 606

		if (em->block_start < EXTENT_MAP_LAST_BYTE &&
		    em->start < start) {
			split->start = em->start;
			split->len = start - em->start;
607
			split->orig_start = em->orig_start;
608
			split->block_start = em->block_start;
C
Chris Mason 已提交
609 610 611 612 613

			if (compressed)
				split->block_len = em->block_len;
			else
				split->block_len = split->len;
J
Josef Bacik 已提交
614
			split->ram_bytes = em->ram_bytes;
615 616
			split->orig_block_len = max(split->block_len,
						    em->orig_block_len);
J
Josef Bacik 已提交
617
			split->generation = gen;
618
			split->bdev = em->bdev;
619
			split->flags = flags;
620
			split->compress_type = em->compress_type;
J
Josef Bacik 已提交
621
			ret = add_extent_mapping(em_tree, split, modified);
622
			BUG_ON(ret); /* Logic error */
623 624 625 626 627 628 629 630 631 632 633
			free_extent_map(split);
			split = split2;
			split2 = NULL;
		}
		if (em->block_start < EXTENT_MAP_LAST_BYTE &&
		    testend && em->start + em->len > start + len) {
			u64 diff = start + len - em->start;

			split->start = start + len;
			split->len = em->start + em->len - (start + len);
			split->bdev = em->bdev;
634
			split->flags = flags;
635
			split->compress_type = em->compress_type;
J
Josef Bacik 已提交
636
			split->generation = gen;
637 638
			split->orig_block_len = max(em->block_len,
						    em->orig_block_len);
J
Josef Bacik 已提交
639
			split->ram_bytes = em->ram_bytes;
640

C
Chris Mason 已提交
641 642 643
			if (compressed) {
				split->block_len = em->block_len;
				split->block_start = em->block_start;
644
				split->orig_start = em->orig_start;
C
Chris Mason 已提交
645 646 647
			} else {
				split->block_len = split->len;
				split->block_start = em->block_start + diff;
648
				split->orig_start = em->orig_start;
C
Chris Mason 已提交
649
			}
650

J
Josef Bacik 已提交
651
			ret = add_extent_mapping(em_tree, split, modified);
652
			BUG_ON(ret); /* Logic error */
653 654 655
			free_extent_map(split);
			split = NULL;
		}
656
next:
657
		write_unlock(&em_tree->lock);
658

659 660 661 662 663
		/* once for us */
		free_extent_map(em);
		/* once for the tree*/
		free_extent_map(em);
	}
664 665 666 667
	if (split)
		free_extent_map(split);
	if (split2)
		free_extent_map(split2);
668 669
}

C
Chris Mason 已提交
670 671 672 673 674 675 676 677 678
/*
 * 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
679 680 681
int __btrfs_drop_extents(struct btrfs_trans_handle *trans,
			 struct btrfs_root *root, struct inode *inode,
			 struct btrfs_path *path, u64 start, u64 end,
J
Josef Bacik 已提交
682
			 u64 *drop_end, int drop_cache)
C
Chris Mason 已提交
683
{
684
	struct extent_buffer *leaf;
Y
Yan, Zheng 已提交
685
	struct btrfs_file_extent_item *fi;
686
	struct btrfs_key key;
Y
Yan, Zheng 已提交
687
	struct btrfs_key new_key;
L
Li Zefan 已提交
688
	u64 ino = btrfs_ino(inode);
Y
Yan, Zheng 已提交
689 690 691 692 693 694 695 696
	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
697
	int recow;
698
	int ret;
699
	int modify_tree = -1;
J
Josef Bacik 已提交
700
	int update_refs = (root->ref_cows || root == root->fs_info->tree_root);
701
	int found = 0;
C
Chris Mason 已提交
702

C
Chris Mason 已提交
703 704
	if (drop_cache)
		btrfs_drop_extent_cache(inode, start, end - 1, 0);
705

706 707 708
	if (start >= BTRFS_I(inode)->disk_i_size)
		modify_tree = 0;

C
Chris Mason 已提交
709
	while (1) {
C
Chris Mason 已提交
710
		recow = 0;
L
Li Zefan 已提交
711
		ret = btrfs_lookup_file_extent(trans, root, path, ino,
712
					       search_start, modify_tree);
C
Chris Mason 已提交
713
		if (ret < 0)
Y
Yan, Zheng 已提交
714 715 716 717
			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
718
			if (key.objectid == ino &&
Y
Yan, Zheng 已提交
719 720
			    key.type == BTRFS_EXTENT_DATA_KEY)
				path->slots[0]--;
C
Chris Mason 已提交
721
		}
Y
Yan, Zheng 已提交
722
		ret = 0;
723
next_slot:
724
		leaf = path->nodes[0];
Y
Yan, Zheng 已提交
725 726 727 728 729 730 731 732
		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;
733
			}
Y
Yan, Zheng 已提交
734 735 736 737 738
			leaf = path->nodes[0];
			recow = 1;
		}

		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
L
Li Zefan 已提交
739
		if (key.objectid > ino ||
Y
Yan, Zheng 已提交
740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756
		    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 +
				btrfs_file_extent_inline_len(leaf, fi);
757
		} else {
Y
Yan, Zheng 已提交
758
			WARN_ON(1);
759
			extent_end = search_start;
C
Chris Mason 已提交
760 761
		}

Y
Yan, Zheng 已提交
762 763
		if (extent_end <= search_start) {
			path->slots[0]++;
764
			goto next_slot;
C
Chris Mason 已提交
765 766
		}

767
		found = 1;
Y
Yan, Zheng 已提交
768
		search_start = max(key.offset, start);
769 770
		if (recow || !modify_tree) {
			modify_tree = -1;
771
			btrfs_release_path(path);
Y
Yan, Zheng 已提交
772
			continue;
C
Chris Mason 已提交
773
		}
Y
Yan Zheng 已提交
774

Y
Yan, Zheng 已提交
775 776 777 778 779 780 781 782 783 784 785 786 787
		/*
		 *     | - range to drop - |
		 *  | -------- extent -------- |
		 */
		if (start > key.offset && end < extent_end) {
			BUG_ON(del_nr > 0);
			BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);

			memcpy(&new_key, &key, sizeof(new_key));
			new_key.offset = start;
			ret = btrfs_duplicate_item(trans, root, path,
						   &new_key);
			if (ret == -EAGAIN) {
788
				btrfs_release_path(path);
Y
Yan, Zheng 已提交
789
				continue;
Y
Yan Zheng 已提交
790
			}
Y
Yan, Zheng 已提交
791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808
			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
809
			if (update_refs && disk_bytenr > 0) {
810
				ret = btrfs_inc_extent_ref(trans, root,
Y
Yan, Zheng 已提交
811 812 813
						disk_bytenr, num_bytes, 0,
						root->root_key.objectid,
						new_key.objectid,
A
Arne Jansen 已提交
814
						start - extent_offset, 0);
815
				BUG_ON(ret); /* -ENOMEM */
816
			}
Y
Yan, Zheng 已提交
817
			key.offset = start;
Y
Yan Zheng 已提交
818
		}
Y
Yan, Zheng 已提交
819 820 821 822 823 824
		/*
		 *  | ---- range to drop ----- |
		 *      | -------- extent -------- |
		 */
		if (start <= key.offset && end < extent_end) {
			BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
Y
Yan Zheng 已提交
825

Y
Yan, Zheng 已提交
826 827
			memcpy(&new_key, &key, sizeof(new_key));
			new_key.offset = end;
828
			btrfs_set_item_key_safe(root, path, &new_key);
Y
Yan Zheng 已提交
829

Y
Yan, Zheng 已提交
830 831 832 833 834
			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);
835
			if (update_refs && disk_bytenr > 0)
Y
Yan, Zheng 已提交
836 837
				inode_sub_bytes(inode, end - key.offset);
			break;
C
Chris Mason 已提交
838
		}
839

Y
Yan, Zheng 已提交
840 841 842 843 844 845 846 847
		search_start = extent_end;
		/*
		 *       | ---- range to drop ----- |
		 *  | -------- extent -------- |
		 */
		if (start > key.offset && end >= extent_end) {
			BUG_ON(del_nr > 0);
			BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
848

Y
Yan, Zheng 已提交
849 850 851
			btrfs_set_file_extent_num_bytes(leaf, fi,
							start - key.offset);
			btrfs_mark_buffer_dirty(leaf);
852
			if (update_refs && disk_bytenr > 0)
Y
Yan, Zheng 已提交
853 854 855
				inode_sub_bytes(inode, extent_end - start);
			if (end == extent_end)
				break;
C
Chris Mason 已提交
856

Y
Yan, Zheng 已提交
857 858
			path->slots[0]++;
			goto next_slot;
Z
Zheng Yan 已提交
859 860
		}

Y
Yan, Zheng 已提交
861 862 863 864 865 866 867 868 869 870 871 872
		/*
		 *  | ---- 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
873

J
Josef Bacik 已提交
874 875
			if (update_refs &&
			    extent_type == BTRFS_FILE_EXTENT_INLINE) {
876
				inode_sub_bytes(inode,
Y
Yan, Zheng 已提交
877 878 879
						extent_end - key.offset);
				extent_end = ALIGN(extent_end,
						   root->sectorsize);
J
Josef Bacik 已提交
880
			} else if (update_refs && disk_bytenr > 0) {
Z
Zheng Yan 已提交
881
				ret = btrfs_free_extent(trans, root,
Y
Yan, Zheng 已提交
882 883
						disk_bytenr, num_bytes, 0,
						root->root_key.objectid,
884
						key.objectid, key.offset -
A
Arne Jansen 已提交
885
						extent_offset, 0);
886
				BUG_ON(ret); /* -ENOMEM */
Y
Yan, Zheng 已提交
887 888
				inode_sub_bytes(inode,
						extent_end - key.offset);
Z
Zheng Yan 已提交
889 890
			}

Y
Yan, Zheng 已提交
891 892 893 894 895 896 897 898 899 900
			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);
901 902
			if (ret) {
				btrfs_abort_transaction(trans, root, ret);
J
Josef Bacik 已提交
903
				break;
904
			}
Y
Yan, Zheng 已提交
905 906 907 908

			del_nr = 0;
			del_slot = 0;

909
			btrfs_release_path(path);
Y
Yan, Zheng 已提交
910
			continue;
C
Chris Mason 已提交
911
		}
Y
Yan, Zheng 已提交
912 913

		BUG_ON(1);
C
Chris Mason 已提交
914
	}
Y
Yan, Zheng 已提交
915

916
	if (!ret && del_nr > 0) {
Y
Yan, Zheng 已提交
917
		ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
918 919
		if (ret)
			btrfs_abort_transaction(trans, root, ret);
Y
Yan Zheng 已提交
920
	}
Y
Yan, Zheng 已提交
921

J
Josef Bacik 已提交
922
	if (drop_end)
923
		*drop_end = found ? min(end, extent_end) : end;
J
Josef Bacik 已提交
924 925 926 927 928 929
	btrfs_release_path(path);
	return ret;
}

int btrfs_drop_extents(struct btrfs_trans_handle *trans,
		       struct btrfs_root *root, struct inode *inode, u64 start,
930
		       u64 end, int drop_cache)
J
Josef Bacik 已提交
931 932 933 934 935 936 937
{
	struct btrfs_path *path;
	int ret;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;
J
Josef Bacik 已提交
938
	ret = __btrfs_drop_extents(trans, root, inode, path, start, end, NULL,
939
				   drop_cache);
Y
Yan, Zheng 已提交
940
	btrfs_free_path(path);
C
Chris Mason 已提交
941 942 943
	return ret;
}

Y
Yan Zheng 已提交
944
static int extent_mergeable(struct extent_buffer *leaf, int slot,
945 946
			    u64 objectid, u64 bytenr, u64 orig_offset,
			    u64 *start, u64 *end)
Y
Yan Zheng 已提交
947 948 949 950 951 952 953 954 955 956 957 958 959 960 961
{
	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 ||
962
	    btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
Y
Yan Zheng 已提交
963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986
	    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
987
	struct btrfs_root *root = BTRFS_I(inode)->root;
Y
Yan Zheng 已提交
988 989 990 991
	struct extent_buffer *leaf;
	struct btrfs_path *path;
	struct btrfs_file_extent_item *fi;
	struct btrfs_key key;
Y
Yan, Zheng 已提交
992
	struct btrfs_key new_key;
Y
Yan Zheng 已提交
993 994 995
	u64 bytenr;
	u64 num_bytes;
	u64 extent_end;
996
	u64 orig_offset;
Y
Yan Zheng 已提交
997 998
	u64 other_start;
	u64 other_end;
Y
Yan, Zheng 已提交
999 1000 1001
	u64 split;
	int del_nr = 0;
	int del_slot = 0;
1002
	int recow;
Y
Yan Zheng 已提交
1003
	int ret;
L
Li Zefan 已提交
1004
	u64 ino = btrfs_ino(inode);
Y
Yan Zheng 已提交
1005 1006

	path = btrfs_alloc_path();
1007 1008
	if (!path)
		return -ENOMEM;
Y
Yan Zheng 已提交
1009
again:
1010
	recow = 0;
Y
Yan, Zheng 已提交
1011
	split = start;
L
Li Zefan 已提交
1012
	key.objectid = ino;
Y
Yan Zheng 已提交
1013
	key.type = BTRFS_EXTENT_DATA_KEY;
Y
Yan, Zheng 已提交
1014
	key.offset = split;
Y
Yan Zheng 已提交
1015 1016

	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1017 1018
	if (ret < 0)
		goto out;
Y
Yan Zheng 已提交
1019 1020 1021 1022 1023
	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
1024
	BUG_ON(key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY);
Y
Yan Zheng 已提交
1025 1026
	fi = btrfs_item_ptr(leaf, path->slots[0],
			    struct btrfs_file_extent_item);
Y
Yan, Zheng 已提交
1027 1028
	BUG_ON(btrfs_file_extent_type(leaf, fi) !=
	       BTRFS_FILE_EXTENT_PREALLOC);
Y
Yan Zheng 已提交
1029 1030 1031 1032 1033
	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);
1034
	orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
1035 1036 1037 1038 1039 1040
	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
1041
				     ino, bytenr, orig_offset,
1042 1043
				     &other_start, &other_end)) {
			new_key.offset = end;
1044
			btrfs_set_item_key_safe(root, path, &new_key);
1045 1046
			fi = btrfs_item_ptr(leaf, path->slots[0],
					    struct btrfs_file_extent_item);
1047 1048
			btrfs_set_file_extent_generation(leaf, fi,
							 trans->transid);
1049 1050 1051 1052 1053 1054
			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);
1055 1056
			btrfs_set_file_extent_generation(leaf, fi,
							 trans->transid);
1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067
			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
1068
				     ino, bytenr, orig_offset,
1069 1070 1071 1072 1073
				     &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);
1074 1075
			btrfs_set_file_extent_generation(leaf, fi,
							 trans->transid);
1076 1077
			path->slots[0]++;
			new_key.offset = start;
1078
			btrfs_set_item_key_safe(root, path, &new_key);
1079 1080 1081

			fi = btrfs_item_ptr(leaf, path->slots[0],
					    struct btrfs_file_extent_item);
1082 1083
			btrfs_set_file_extent_generation(leaf, fi,
							 trans->transid);
1084 1085 1086 1087 1088 1089 1090 1091
			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
1092

Y
Yan, Zheng 已提交
1093 1094 1095 1096 1097 1098 1099
	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) {
1100
			btrfs_release_path(path);
Y
Yan, Zheng 已提交
1101
			goto again;
Y
Yan Zheng 已提交
1102
		}
1103 1104 1105 1106
		if (ret < 0) {
			btrfs_abort_transaction(trans, root, ret);
			goto out;
		}
Y
Yan Zheng 已提交
1107

Y
Yan, Zheng 已提交
1108 1109
		leaf = path->nodes[0];
		fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
Y
Yan Zheng 已提交
1110
				    struct btrfs_file_extent_item);
1111
		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
Y
Yan Zheng 已提交
1112
		btrfs_set_file_extent_num_bytes(leaf, fi,
Y
Yan, Zheng 已提交
1113 1114 1115 1116 1117
						split - key.offset);

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

1118
		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
Y
Yan, Zheng 已提交
1119 1120 1121
		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
1122 1123
		btrfs_mark_buffer_dirty(leaf);

Y
Yan, Zheng 已提交
1124 1125
		ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
					   root->root_key.objectid,
A
Arne Jansen 已提交
1126
					   ino, orig_offset, 0);
1127
		BUG_ON(ret); /* -ENOMEM */
Y
Yan Zheng 已提交
1128

Y
Yan, Zheng 已提交
1129 1130 1131 1132
		if (split == start) {
			key.offset = start;
		} else {
			BUG_ON(start != key.offset);
Y
Yan Zheng 已提交
1133
			path->slots[0]--;
Y
Yan, Zheng 已提交
1134
			extent_end = end;
Y
Yan Zheng 已提交
1135
		}
1136
		recow = 1;
Y
Yan Zheng 已提交
1137 1138
	}

Y
Yan, Zheng 已提交
1139 1140
	other_start = end;
	other_end = 0;
1141
	if (extent_mergeable(leaf, path->slots[0] + 1,
L
Li Zefan 已提交
1142
			     ino, bytenr, orig_offset,
1143 1144
			     &other_start, &other_end)) {
		if (recow) {
1145
			btrfs_release_path(path);
1146 1147
			goto again;
		}
Y
Yan, Zheng 已提交
1148 1149 1150 1151 1152
		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
1153
					ino, orig_offset, 0);
1154
		BUG_ON(ret); /* -ENOMEM */
Y
Yan Zheng 已提交
1155
	}
Y
Yan, Zheng 已提交
1156 1157
	other_start = 0;
	other_end = start;
1158
	if (extent_mergeable(leaf, path->slots[0] - 1,
L
Li Zefan 已提交
1159
			     ino, bytenr, orig_offset,
1160 1161
			     &other_start, &other_end)) {
		if (recow) {
1162
			btrfs_release_path(path);
1163 1164
			goto again;
		}
Y
Yan, Zheng 已提交
1165 1166 1167 1168 1169
		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
1170
					ino, orig_offset, 0);
1171
		BUG_ON(ret); /* -ENOMEM */
Y
Yan, Zheng 已提交
1172 1173
	}
	if (del_nr == 0) {
1174 1175
		fi = btrfs_item_ptr(leaf, path->slots[0],
			   struct btrfs_file_extent_item);
Y
Yan, Zheng 已提交
1176 1177
		btrfs_set_file_extent_type(leaf, fi,
					   BTRFS_FILE_EXTENT_REG);
1178
		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
Y
Yan, Zheng 已提交
1179
		btrfs_mark_buffer_dirty(leaf);
1180
	} else {
1181 1182
		fi = btrfs_item_ptr(leaf, del_slot - 1,
			   struct btrfs_file_extent_item);
1183 1184
		btrfs_set_file_extent_type(leaf, fi,
					   BTRFS_FILE_EXTENT_REG);
1185
		btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1186 1187 1188
		btrfs_set_file_extent_num_bytes(leaf, fi,
						extent_end - key.offset);
		btrfs_mark_buffer_dirty(leaf);
Y
Yan, Zheng 已提交
1189

1190
		ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
1191 1192 1193 1194
		if (ret < 0) {
			btrfs_abort_transaction(trans, root, ret);
			goto out;
		}
1195
	}
Y
Yan, Zheng 已提交
1196
out:
Y
Yan Zheng 已提交
1197 1198 1199 1200
	btrfs_free_path(path);
	return 0;
}

1201 1202 1203 1204
/*
 * on error we return an unlocked page and the error value
 * on success we return a locked page and 0
 */
1205 1206
static int prepare_uptodate_page(struct page *page, u64 pos,
				 bool force_uptodate)
1207 1208 1209
{
	int ret = 0;

1210 1211
	if (((pos & (PAGE_CACHE_SIZE - 1)) || force_uptodate) &&
	    !PageUptodate(page)) {
1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223
		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
1224
/*
C
Chris Mason 已提交
1225 1226 1227
 * this gets pages into the page cache and locks them down, it also properly
 * waits for data=ordered extents to finish before allowing the pages to be
 * modified.
C
Chris Mason 已提交
1228
 */
C
Chris Mason 已提交
1229
static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
1230 1231
			 struct page **pages, size_t num_pages,
			 loff_t pos, unsigned long first_index,
1232
			 size_t write_bytes, bool force_uptodate)
C
Chris Mason 已提交
1233
{
1234
	struct extent_state *cached_state = NULL;
C
Chris Mason 已提交
1235 1236
	int i;
	unsigned long index = pos >> PAGE_CACHE_SHIFT;
A
Al Viro 已提交
1237
	struct inode *inode = file_inode(file);
1238
	gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
C
Chris Mason 已提交
1239
	int err = 0;
1240
	int faili = 0;
1241
	u64 start_pos;
1242
	u64 last_pos;
1243

1244
	start_pos = pos & ~((u64)root->sectorsize - 1);
1245
	last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
C
Chris Mason 已提交
1246

1247
again:
C
Chris Mason 已提交
1248
	for (i = 0; i < num_pages; i++) {
1249
		pages[i] = find_or_create_page(inode->i_mapping, index + i,
1250
					       mask | __GFP_WRITE);
C
Chris Mason 已提交
1251
		if (!pages[i]) {
1252 1253 1254 1255 1256 1257
			faili = i - 1;
			err = -ENOMEM;
			goto fail;
		}

		if (i == 0)
1258 1259
			err = prepare_uptodate_page(pages[i], pos,
						    force_uptodate);
1260 1261
		if (i == num_pages - 1)
			err = prepare_uptodate_page(pages[i],
1262
						    pos + write_bytes, false);
1263 1264 1265 1266
		if (err) {
			page_cache_release(pages[i]);
			faili = i - 1;
			goto fail;
C
Chris Mason 已提交
1267
		}
C
Chris Mason 已提交
1268
		wait_on_page_writeback(pages[i]);
C
Chris Mason 已提交
1269
	}
1270
	err = 0;
1271
	if (start_pos < inode->i_size) {
1272
		struct btrfs_ordered_extent *ordered;
1273
		lock_extent_bits(&BTRFS_I(inode)->io_tree,
1274
				 start_pos, last_pos - 1, 0, &cached_state);
C
Chris Mason 已提交
1275 1276
		ordered = btrfs_lookup_first_ordered_extent(inode,
							    last_pos - 1);
1277 1278 1279 1280
		if (ordered &&
		    ordered->file_offset + ordered->len > start_pos &&
		    ordered->file_offset < last_pos) {
			btrfs_put_ordered_extent(ordered);
1281 1282 1283
			unlock_extent_cached(&BTRFS_I(inode)->io_tree,
					     start_pos, last_pos - 1,
					     &cached_state, GFP_NOFS);
1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294
			for (i = 0; i < num_pages; i++) {
				unlock_page(pages[i]);
				page_cache_release(pages[i]);
			}
			btrfs_wait_ordered_range(inode, start_pos,
						 last_pos - start_pos);
			goto again;
		}
		if (ordered)
			btrfs_put_ordered_extent(ordered);

1295
		clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
1296
				  last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
1297 1298
				  EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
				  0, 0, &cached_state, GFP_NOFS);
1299 1300 1301
		unlock_extent_cached(&BTRFS_I(inode)->io_tree,
				     start_pos, last_pos - 1, &cached_state,
				     GFP_NOFS);
1302
	}
1303
	for (i = 0; i < num_pages; i++) {
1304 1305
		if (clear_page_dirty_for_io(pages[i]))
			account_page_redirty(pages[i]);
1306 1307 1308
		set_page_extent_mapped(pages[i]);
		WARN_ON(!PageLocked(pages[i]));
	}
C
Chris Mason 已提交
1309
	return 0;
1310 1311 1312 1313 1314 1315 1316 1317
fail:
	while (faili >= 0) {
		unlock_page(pages[faili]);
		page_cache_release(pages[faili]);
		faili--;
	}
	return err;

C
Chris Mason 已提交
1318 1319
}

J
Josef Bacik 已提交
1320 1321 1322
static noinline ssize_t __btrfs_buffered_write(struct file *file,
					       struct iov_iter *i,
					       loff_t pos)
1323
{
A
Al Viro 已提交
1324
	struct inode *inode = file_inode(file);
1325 1326
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct page **pages = NULL;
C
Chris Mason 已提交
1327
	unsigned long first_index;
J
Josef Bacik 已提交
1328 1329
	size_t num_written = 0;
	int nrptrs;
1330
	int ret = 0;
1331
	bool force_page_uptodate = false;
1332

J
Josef Bacik 已提交
1333
	nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
1334 1335
		     PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
		     (sizeof(struct page *)));
1336 1337
	nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
	nrptrs = max(nrptrs, 8);
1338
	pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
J
Josef Bacik 已提交
1339 1340
	if (!pages)
		return -ENOMEM;
1341

C
Chris Mason 已提交
1342 1343
	first_index = pos >> PAGE_CACHE_SHIFT;

J
Josef Bacik 已提交
1344
	while (iov_iter_count(i) > 0) {
C
Chris Mason 已提交
1345
		size_t offset = pos & (PAGE_CACHE_SIZE - 1);
J
Josef Bacik 已提交
1346
		size_t write_bytes = min(iov_iter_count(i),
1347
					 nrptrs * (size_t)PAGE_CACHE_SIZE -
1348
					 offset);
Y
Yan, Zheng 已提交
1349 1350
		size_t num_pages = (write_bytes + offset +
				    PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
J
Josef Bacik 已提交
1351 1352
		size_t dirty_pages;
		size_t copied;
C
Chris Mason 已提交
1353

1354
		WARN_ON(num_pages > nrptrs);
1355

1356 1357 1358 1359
		/*
		 * Fault pages before locking them in prepare_pages
		 * to avoid recursive lock
		 */
J
Josef Bacik 已提交
1360
		if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
1361
			ret = -EFAULT;
J
Josef Bacik 已提交
1362
			break;
1363 1364 1365 1366
		}

		ret = btrfs_delalloc_reserve_space(inode,
					num_pages << PAGE_CACHE_SHIFT);
1367
		if (ret)
J
Josef Bacik 已提交
1368
			break;
1369

1370 1371 1372 1373 1374
		/*
		 * 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
		 */
C
Chris Mason 已提交
1375
		ret = prepare_pages(root, file, pages, num_pages,
1376 1377
				    pos, first_index, write_bytes,
				    force_page_uptodate);
J
Josef Bacik 已提交
1378
		if (ret) {
1379 1380
			btrfs_delalloc_release_space(inode,
					num_pages << PAGE_CACHE_SHIFT);
J
Josef Bacik 已提交
1381
			break;
J
Josef Bacik 已提交
1382
		}
C
Chris Mason 已提交
1383

1384
		copied = btrfs_copy_from_user(pos, num_pages,
J
Josef Bacik 已提交
1385
					   write_bytes, pages, i);
1386 1387 1388 1389 1390 1391 1392 1393

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

1394 1395
		if (copied == 0) {
			force_page_uptodate = true;
1396
			dirty_pages = 0;
1397 1398
		} else {
			force_page_uptodate = false;
1399 1400 1401
			dirty_pages = (copied + offset +
				       PAGE_CACHE_SIZE - 1) >>
				       PAGE_CACHE_SHIFT;
1402
		}
1403

J
Josef Bacik 已提交
1404 1405 1406 1407 1408 1409 1410
		/*
		 * 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.
		 */
1411
		if (num_pages > dirty_pages) {
1412 1413 1414 1415 1416
			if (copied > 0) {
				spin_lock(&BTRFS_I(inode)->lock);
				BTRFS_I(inode)->outstanding_extents++;
				spin_unlock(&BTRFS_I(inode)->lock);
			}
1417 1418 1419 1420 1421 1422
			btrfs_delalloc_release_space(inode,
					(num_pages - dirty_pages) <<
					PAGE_CACHE_SHIFT);
		}

		if (copied > 0) {
1423 1424 1425
			ret = btrfs_dirty_pages(root, inode, pages,
						dirty_pages, pos, copied,
						NULL);
J
Josef Bacik 已提交
1426 1427 1428 1429 1430 1431
			if (ret) {
				btrfs_delalloc_release_space(inode,
					dirty_pages << PAGE_CACHE_SHIFT);
				btrfs_drop_pages(pages, num_pages);
				break;
			}
1432
		}
C
Chris Mason 已提交
1433 1434 1435

		btrfs_drop_pages(pages, num_pages);

J
Josef Bacik 已提交
1436 1437
		cond_resched();

1438
		balance_dirty_pages_ratelimited(inode->i_mapping);
J
Josef Bacik 已提交
1439
		if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
1440
			btrfs_btree_balance_dirty(root);
1441

1442 1443
		pos += copied;
		num_written += copied;
J
Josef Bacik 已提交
1444
	}
C
Chris Mason 已提交
1445

J
Josef Bacik 已提交
1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475
	kfree(pages);

	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
1476
	}
J
Josef Bacik 已提交
1477 1478 1479 1480 1481 1482 1483 1484
	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
1485
out:
J
Josef Bacik 已提交
1486 1487
	return written ? written : err;
}
1488

1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506
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
1507 1508 1509 1510 1511
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
1512
	struct inode *inode = file_inode(file);
J
Josef Bacik 已提交
1513 1514
	struct btrfs_root *root = BTRFS_I(inode)->root;
	loff_t *ppos = &iocb->ki_pos;
1515
	u64 start_pos;
J
Josef Bacik 已提交
1516 1517 1518
	ssize_t num_written = 0;
	ssize_t err = 0;
	size_t count, ocount;
1519
	bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host);
J
Josef Bacik 已提交
1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553

	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.
	 */
1554
	if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
J
Josef Bacik 已提交
1555 1556 1557 1558 1559
		mutex_unlock(&inode->i_mutex);
		err = -EROFS;
		goto out;
	}

1560 1561 1562 1563 1564 1565 1566
	/*
	 * 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
1567

1568 1569 1570 1571 1572 1573 1574 1575 1576
	start_pos = round_down(pos, root->sectorsize);
	if (start_pos > i_size_read(inode)) {
		err = btrfs_cont_expand(inode, i_size_read(inode), start_pos);
		if (err) {
			mutex_unlock(&inode->i_mutex);
			goto out;
		}
	}

1577 1578 1579
	if (sync)
		atomic_inc(&BTRFS_I(inode)->sync_writers);

J
Josef Bacik 已提交
1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593
	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);
1594

1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605
	/*
	 * 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.
1606 1607 1608 1609
	 *
	 * 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.
1610 1611
	 */
	BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
1612
	BTRFS_I(inode)->last_sub_trans = root->log_transid;
J
Josef Bacik 已提交
1613 1614 1615
	if (num_written > 0 || num_written == -EIOCBQUEUED) {
		err = generic_write_sync(file, pos, num_written);
		if (err < 0 && num_written > 0)
1616 1617
			num_written = err;
	}
1618

1619 1620
	if (sync)
		atomic_dec(&BTRFS_I(inode)->sync_writers);
1621
out:
C
Chris Mason 已提交
1622 1623 1624 1625
	current->backing_dev_info = NULL;
	return num_written ? num_written : err;
}

C
Chris Mason 已提交
1626
int btrfs_release_file(struct inode *inode, struct file *filp)
1627
{
1628 1629 1630 1631 1632 1633
	/*
	 * 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.
	 */
1634 1635
	if (test_and_clear_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
			       &BTRFS_I(inode)->runtime_flags)) {
1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649
		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);
1650 1651 1652
		if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
			filemap_flush(inode->i_mapping);
	}
S
Sage Weil 已提交
1653 1654
	if (filp->private_data)
		btrfs_ioctl_trans_end(filp);
1655 1656 1657
	return 0;
}

C
Chris Mason 已提交
1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668
/*
 * 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.
 */
1669
int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
C
Chris Mason 已提交
1670
{
1671
	struct dentry *dentry = file->f_path.dentry;
C
Chris Mason 已提交
1672 1673
	struct inode *inode = dentry->d_inode;
	struct btrfs_root *root = BTRFS_I(inode)->root;
1674
	int ret = 0;
C
Chris Mason 已提交
1675
	struct btrfs_trans_handle *trans;
1676
	bool full_sync = 0;
C
Chris Mason 已提交
1677

1678
	trace_btrfs_sync_file(file, datasync);
1679

1680 1681 1682
	/*
	 * 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
1683 1684
	 * multi-task, and make the performance up.  See
	 * btrfs_wait_ordered_range for an explanation of the ASYNC check.
1685
	 */
1686
	atomic_inc(&BTRFS_I(inode)->sync_writers);
1687 1688 1689 1690
	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);
1691
	atomic_dec(&BTRFS_I(inode)->sync_writers);
1692 1693 1694
	if (ret)
		return ret;

1695 1696
	mutex_lock(&inode->i_mutex);

1697
	/*
1698 1699
	 * We flush the dirty pages again to avoid some dirty pages in the
	 * range being left.
1700
	 */
M
Miao Xie 已提交
1701
	atomic_inc(&root->log_batch);
1702 1703 1704 1705
	full_sync = test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
			     &BTRFS_I(inode)->runtime_flags);
	if (full_sync)
		btrfs_wait_ordered_range(inode, start, end - start + 1);
M
Miao Xie 已提交
1706
	atomic_inc(&root->log_batch);
1707

C
Chris Mason 已提交
1708
	/*
1709 1710
	 * check the transaction that last modified this inode
	 * and see if its already been committed
C
Chris Mason 已提交
1711
	 */
1712 1713
	if (!BTRFS_I(inode)->last_trans) {
		mutex_unlock(&inode->i_mutex);
1714
		goto out;
1715
	}
1716

1717 1718 1719 1720 1721
	/*
	 * 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
1722
	smp_mb();
1723 1724
	if (btrfs_inode_in_log(inode, root->fs_info->generation) ||
	    BTRFS_I(inode)->last_trans <=
1725 1726
	    root->fs_info->last_trans_committed) {
		BTRFS_I(inode)->last_trans = 0;
J
Josef Bacik 已提交
1727 1728 1729 1730 1731 1732 1733 1734

		/*
		 * 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);
1735
		mutex_unlock(&inode->i_mutex);
1736 1737 1738 1739
		goto out;
	}

	/*
1740 1741
	 * ok we haven't committed the transaction yet, lets do a commit
	 */
1742
	if (file->private_data)
S
Sage Weil 已提交
1743 1744
		btrfs_ioctl_trans_end(file);

1745 1746 1747
	trans = btrfs_start_transaction(root, 0);
	if (IS_ERR(trans)) {
		ret = PTR_ERR(trans);
1748
		mutex_unlock(&inode->i_mutex);
C
Chris Mason 已提交
1749 1750
		goto out;
	}
1751

1752
	ret = btrfs_log_dentry_safe(trans, root, dentry);
1753 1754
	if (ret < 0) {
		mutex_unlock(&inode->i_mutex);
1755
		goto out;
1756
	}
C
Chris Mason 已提交
1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767

	/* 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.
	 */
1768
	mutex_unlock(&inode->i_mutex);
C
Chris Mason 已提交
1769

1770 1771
	if (ret != BTRFS_NO_LOG_SYNC) {
		if (ret > 0) {
1772 1773 1774 1775 1776 1777 1778
			/*
			 * If we didn't already wait for ordered extents we need
			 * to do that now.
			 */
			if (!full_sync)
				btrfs_wait_ordered_range(inode, start,
							 end - start + 1);
1779
			ret = btrfs_commit_transaction(trans, root);
1780 1781
		} else {
			ret = btrfs_sync_log(trans, root);
1782
			if (ret == 0) {
1783
				ret = btrfs_end_transaction(trans, root);
1784 1785 1786 1787 1788
			} else {
				if (!full_sync)
					btrfs_wait_ordered_range(inode, start,
								 end -
								 start + 1);
1789
				ret = btrfs_commit_transaction(trans, root);
1790
			}
1791 1792 1793
		}
	} else {
		ret = btrfs_end_transaction(trans, root);
1794
	}
C
Chris Mason 已提交
1795
out:
1796
	return ret > 0 ? -EIO : ret;
C
Chris Mason 已提交
1797 1798
}

1799
static const struct vm_operations_struct btrfs_file_vm_ops = {
1800
	.fault		= filemap_fault,
C
Chris Mason 已提交
1801
	.page_mkwrite	= btrfs_page_mkwrite,
1802
	.remap_pages	= generic_file_remap_pages,
C
Chris Mason 已提交
1803 1804 1805 1806
};

static int btrfs_file_mmap(struct file	*filp, struct vm_area_struct *vma)
{
M
Miao Xie 已提交
1807 1808 1809 1810 1811
	struct address_space *mapping = filp->f_mapping;

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

C
Chris Mason 已提交
1812
	file_accessed(filp);
M
Miao Xie 已提交
1813 1814
	vma->vm_ops = &btrfs_file_vm_ops;

C
Chris Mason 已提交
1815 1816 1817
	return 0;
}

J
Josef Bacik 已提交
1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888
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;

	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;
1889
		btrfs_set_item_key_safe(root, path, &key);
J
Josef Bacik 已提交
1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918
		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
1919
		hole_em->ram_bytes = hole_em->len;
J
Josef Bacik 已提交
1920 1921 1922 1923
		hole_em->orig_start = offset;

		hole_em->block_start = EXTENT_MAP_HOLE;
		hole_em->block_len = 0;
1924
		hole_em->orig_block_len = 0;
J
Josef Bacik 已提交
1925 1926 1927 1928 1929 1930 1931
		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
1932
			ret = add_extent_mapping(em_tree, hole_em, 1);
J
Josef Bacik 已提交
1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950
			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
1951 1952 1953
	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
1954 1955 1956 1957 1958
	u64 cur_offset = lockstart;
	u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
	u64 drop_end;
	int ret = 0;
	int err = 0;
1959 1960
	bool same_page = ((offset >> PAGE_CACHE_SHIFT) ==
			  ((offset + len - 1) >> PAGE_CACHE_SHIFT));
J
Josef Bacik 已提交
1961 1962 1963 1964

	btrfs_wait_ordered_range(inode, offset, len);

	mutex_lock(&inode->i_mutex);
1965 1966 1967 1968
	/*
	 * We needn't truncate any page which is beyond the end of the file
	 * because we are sure there is no data there.
	 */
J
Josef Bacik 已提交
1969 1970 1971 1972 1973
	/*
	 * 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) {
1974 1975
		if (offset < round_up(inode->i_size, PAGE_CACHE_SIZE))
			ret = btrfs_truncate_page(inode, offset, len, 0);
J
Josef Bacik 已提交
1976 1977 1978 1979 1980
		mutex_unlock(&inode->i_mutex);
		return ret;
	}

	/* zero back part of the first page */
1981 1982 1983 1984 1985 1986
	if (offset < round_up(inode->i_size, PAGE_CACHE_SIZE)) {
		ret = btrfs_truncate_page(inode, offset, 0, 0);
		if (ret) {
			mutex_unlock(&inode->i_mutex);
			return ret;
		}
J
Josef Bacik 已提交
1987 1988 1989
	}

	/* zero the front end of the last page */
M
Miao Xie 已提交
1990 1991 1992 1993 1994 1995
	if (offset + len < round_up(inode->i_size, PAGE_CACHE_SIZE)) {
		ret = btrfs_truncate_page(inode, offset + len, 0, 1);
		if (ret) {
			mutex_unlock(&inode->i_mutex);
			return ret;
		}
J
Josef Bacik 已提交
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040
	}

	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 ||
		    (ordered->file_offset + ordered->len < lockstart ||
		     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);
		btrfs_wait_ordered_range(inode, lockstart,
					 lockend - lockstart + 1);
	}

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

2041
	rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
J
Josef Bacik 已提交
2042 2043 2044 2045 2046 2047 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 2088
	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
	 * 1 - adding the hole extent
	 */
	trans = btrfs_start_transaction(root, 3);
	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,
					   &drop_end, 1);
		if (ret != -ENOSPC)
			break;

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

		ret = fill_holes(trans, inode, path, cur_offset, drop_end);
		if (ret) {
			err = ret;
			break;
		}

		cur_offset = drop_end;

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

		btrfs_end_transaction(trans, root);
2089
		btrfs_btree_balance_dirty(root);
J
Josef Bacik 已提交
2090 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

		trans = btrfs_start_transaction(root, 3);
		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;
	ret = fill_holes(trans, inode, path, cur_offset, drop_end);
	if (ret) {
		err = ret;
		goto out_trans;
	}

out_trans:
	if (!trans)
		goto out_free;

2120 2121 2122
	inode_inc_iversion(inode);
	inode->i_mtime = inode->i_ctime = CURRENT_TIME;

J
Josef Bacik 已提交
2123 2124 2125
	trans->block_rsv = &root->fs_info->trans_block_rsv;
	ret = btrfs_update_inode(trans, root, inode);
	btrfs_end_transaction(trans, root);
2126
	btrfs_btree_balance_dirty(root);
J
Josef Bacik 已提交
2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138
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;
}

2139 2140 2141
static long btrfs_fallocate(struct file *file, int mode,
			    loff_t offset, loff_t len)
{
A
Al Viro 已提交
2142
	struct inode *inode = file_inode(file);
2143
	struct extent_state *cached_state = NULL;
2144
	struct btrfs_root *root = BTRFS_I(inode)->root;
2145 2146 2147 2148 2149 2150 2151
	u64 cur_offset;
	u64 last_byte;
	u64 alloc_start;
	u64 alloc_end;
	u64 alloc_hint = 0;
	u64 locked_end;
	struct extent_map *em;
2152
	int blocksize = BTRFS_I(inode)->root->sectorsize;
2153 2154
	int ret;

2155 2156
	alloc_start = round_down(offset, blocksize);
	alloc_end = round_up(offset + len, blocksize);
2157

J
Josef Bacik 已提交
2158 2159
	/* Make sure we aren't being give some crap mode */
	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
2160 2161
		return -EOPNOTSUPP;

J
Josef Bacik 已提交
2162 2163 2164
	if (mode & FALLOC_FL_PUNCH_HOLE)
		return btrfs_punch_hole(inode, offset, len);

2165 2166 2167 2168
	/*
	 * Make sure we have enough space before we do the
	 * allocation.
	 */
2169
	ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start);
2170 2171
	if (ret)
		return ret;
2172 2173 2174 2175 2176
	if (root->fs_info->quota_enabled) {
		ret = btrfs_qgroup_reserve(root, alloc_end - alloc_start);
		if (ret)
			goto out_reserve_fail;
	}
2177

2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189
	/*
	 * wait for ordered IO before we have any locks.  We'll loop again
	 * below with the locks held.
	 */
	btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start);

	mutex_lock(&inode->i_mutex);
	ret = inode_newsize_ok(inode, alloc_end);
	if (ret)
		goto out;

	if (alloc_start > inode->i_size) {
2190 2191
		ret = btrfs_cont_expand(inode, i_size_read(inode),
					alloc_start);
2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203
		if (ret)
			goto out;
	}

	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,
2204
				 locked_end, 0, &cached_state);
2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228
		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
			 */
			btrfs_wait_ordered_range(inode, alloc_start,
						 alloc_end - alloc_start);
		} else {
			if (ordered)
				btrfs_put_ordered_extent(ordered);
			break;
		}
	}

	cur_offset = alloc_start;
	while (1) {
2229 2230
		u64 actual_end;

2231 2232
		em = btrfs_get_extent(inode, NULL, 0, cur_offset,
				      alloc_end - cur_offset, 0);
2233 2234 2235 2236 2237 2238 2239
		if (IS_ERR_OR_NULL(em)) {
			if (!em)
				ret = -ENOMEM;
			else
				ret = PTR_ERR(em);
			break;
		}
2240
		last_byte = min(extent_map_end(em), alloc_end);
2241
		actual_end = min_t(u64, extent_map_end(em), offset + len);
2242
		last_byte = ALIGN(last_byte, blocksize);
2243

2244 2245 2246 2247 2248 2249 2250 2251
		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);
2252

2253 2254 2255 2256
			if (ret < 0) {
				free_extent_map(em);
				break;
			}
2257 2258 2259 2260 2261 2262 2263 2264 2265 2266
		} 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);
2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279
		}
		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);
2280 2281 2282
	if (root->fs_info->quota_enabled)
		btrfs_qgroup_free(root, alloc_end - alloc_start);
out_reserve_fail:
2283
	/* Let go of our reservation. */
2284
	btrfs_free_reserved_data_space(inode, alloc_end - alloc_start);
2285 2286 2287
	return ret;
}

2288
static int find_desired_extent(struct inode *inode, loff_t *offset, int whence)
J
Josef Bacik 已提交
2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304
{
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct extent_map *em;
	struct extent_state *cached_state = NULL;
	u64 lockstart = *offset;
	u64 lockend = i_size_read(inode);
	u64 start = *offset;
	u64 orig_start = *offset;
	u64 len = i_size_read(inode);
	u64 last_end = 0;
	int ret = 0;

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

L
Liu Bo 已提交
2305
	lockend--;
J
Josef Bacik 已提交
2306 2307 2308 2309 2310 2311 2312
	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,
2313
			 &cached_state);
J
Josef Bacik 已提交
2314 2315 2316 2317 2318 2319 2320 2321 2322

	/*
	 * Delalloc is such a pain.  If we have a hole and we have pending
	 * delalloc for a portion of the hole we will get back a hole that
	 * exists for the entire range since it hasn't been actually written
	 * yet.  So to take care of this case we need to look for an extent just
	 * before the position we want in case there is outstanding delalloc
	 * going on here.
	 */
2323
	if (whence == SEEK_HOLE && start != 0) {
J
Josef Bacik 已提交
2324 2325 2326 2327 2328 2329 2330 2331
		if (start <= root->sectorsize)
			em = btrfs_get_extent_fiemap(inode, NULL, 0, 0,
						     root->sectorsize, 0);
		else
			em = btrfs_get_extent_fiemap(inode, NULL, 0,
						     start - root->sectorsize,
						     root->sectorsize, 0);
		if (IS_ERR(em)) {
2332
			ret = PTR_ERR(em);
J
Josef Bacik 已提交
2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343
			goto out;
		}
		last_end = em->start + em->len;
		if (em->block_start == EXTENT_MAP_DELALLOC)
			last_end = min_t(u64, last_end, inode->i_size);
		free_extent_map(em);
	}

	while (1) {
		em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0);
		if (IS_ERR(em)) {
2344
			ret = PTR_ERR(em);
J
Josef Bacik 已提交
2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356
			break;
		}

		if (em->block_start == EXTENT_MAP_HOLE) {
			if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
				if (last_end <= orig_start) {
					free_extent_map(em);
					ret = -ENXIO;
					break;
				}
			}

2357
			if (whence == SEEK_HOLE) {
J
Josef Bacik 已提交
2358 2359 2360 2361 2362
				*offset = start;
				free_extent_map(em);
				break;
			}
		} else {
2363
			if (whence == SEEK_DATA) {
J
Josef Bacik 已提交
2364 2365 2366 2367 2368 2369 2370 2371
				if (em->block_start == EXTENT_MAP_DELALLOC) {
					if (start >= inode->i_size) {
						free_extent_map(em);
						ret = -ENXIO;
						break;
					}
				}

2372 2373 2374 2375 2376 2377
				if (!test_bit(EXTENT_FLAG_PREALLOC,
					      &em->flags)) {
					*offset = start;
					free_extent_map(em);
					break;
				}
J
Josef Bacik 已提交
2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402
			}
		}

		start = em->start + em->len;
		last_end = em->start + em->len;

		if (em->block_start == EXTENT_MAP_DELALLOC)
			last_end = min_t(u64, last_end, inode->i_size);

		if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
			free_extent_map(em);
			ret = -ENXIO;
			break;
		}
		free_extent_map(em);
		cond_resched();
	}
	if (!ret)
		*offset = min(*offset, inode->i_size);
out:
	unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
			     &cached_state, GFP_NOFS);
	return ret;
}

2403
static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
J
Josef Bacik 已提交
2404 2405 2406 2407 2408
{
	struct inode *inode = file->f_mapping->host;
	int ret;

	mutex_lock(&inode->i_mutex);
2409
	switch (whence) {
J
Josef Bacik 已提交
2410 2411
	case SEEK_END:
	case SEEK_CUR:
2412
		offset = generic_file_llseek(file, offset, whence);
J
Josef Bacik 已提交
2413 2414 2415
		goto out;
	case SEEK_DATA:
	case SEEK_HOLE:
2416 2417 2418 2419 2420
		if (offset >= i_size_read(inode)) {
			mutex_unlock(&inode->i_mutex);
			return -ENXIO;
		}

2421
		ret = find_desired_extent(inode, &offset, whence);
J
Josef Bacik 已提交
2422 2423 2424 2425 2426 2427
		if (ret) {
			mutex_unlock(&inode->i_mutex);
			return ret;
		}
	}

2428
	if (offset < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET)) {
2429
		offset = -EINVAL;
2430 2431 2432
		goto out;
	}
	if (offset > inode->i_sb->s_maxbytes) {
2433
		offset = -EINVAL;
2434 2435
		goto out;
	}
J
Josef Bacik 已提交
2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446

	/* Special lock needed here? */
	if (offset != file->f_pos) {
		file->f_pos = offset;
		file->f_version = 0;
	}
out:
	mutex_unlock(&inode->i_mutex);
	return offset;
}

2447
const struct file_operations btrfs_file_operations = {
J
Josef Bacik 已提交
2448
	.llseek		= btrfs_file_llseek,
C
Chris Mason 已提交
2449
	.read		= do_sync_read,
2450
	.write		= do_sync_write,
C
Chris Mason 已提交
2451
	.aio_read       = generic_file_aio_read,
C
Chris Mason 已提交
2452
	.splice_read	= generic_file_splice_read,
2453
	.aio_write	= btrfs_file_aio_write,
C
Chris Mason 已提交
2454
	.mmap		= btrfs_file_mmap,
C
Chris Mason 已提交
2455
	.open		= generic_file_open,
2456
	.release	= btrfs_release_file,
C
Chris Mason 已提交
2457
	.fsync		= btrfs_sync_file,
2458
	.fallocate	= btrfs_fallocate,
C
Christoph Hellwig 已提交
2459
	.unlocked_ioctl	= btrfs_ioctl,
C
Chris Mason 已提交
2460
#ifdef CONFIG_COMPAT
C
Christoph Hellwig 已提交
2461
	.compat_ioctl	= btrfs_ioctl,
C
Chris Mason 已提交
2462 2463
#endif
};
2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481

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;
}