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Commit bcbfce8a authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: Fix the unplug_io_fn to grab a consistent copy of page->mapping 



Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent e1c4b745

fs/btrfs/disk-io.c

+12 −1
Original line number Diff line number Diff line
@@ -936,14 +936,25 @@ void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page) 
	struct inode *inode;

	struct extent_map_tree *em_tree;

	struct extent_map *em;

	struct address_space *mapping;

	u64 offset;



	/* the generic O_DIRECT read code does this */

	if (!page) {

		__unplug_io_fn(bdi, page);

		return;

	}



	inode = page->mapping->host;

	/*

	 * page->mapping may change at any time.  Get a consistent copy

	 * and use that for everything below

	 */

	smp_mb();

	mapping = page->mapping;

	if (!mapping)

		return;



	inode = mapping->host;

	offset = page_offset(page);



	em_tree = &BTRFS_I(inode)->extent_tree;

fs/btrfs/inode.c

+10 −6
Original line number Diff line number Diff line
@@ -80,6 +80,7 @@ int btrfs_check_free_space(struct btrfs_root *root, u64 num_required, 
	u64 total = btrfs_super_total_bytes(&root->fs_info->super_copy);

	u64 used = btrfs_super_bytes_used(&root->fs_info->super_copy);

	u64 thresh;

	unsigned long flags;

	int ret = 0;



	if (for_del)
@@ -89,10 +90,10 @@ int btrfs_check_free_space(struct btrfs_root *root, u64 num_required, 


	do_div(thresh, 100);



	spin_lock(&root->fs_info->delalloc_lock);

	spin_lock_irqsave(&root->fs_info->delalloc_lock, flags);

	if (used + root->fs_info->delalloc_bytes + num_required > thresh)

		ret = -ENOSPC;

	spin_unlock(&root->fs_info->delalloc_lock);

	spin_unlock_irqrestore(&root->fs_info->delalloc_lock, flags);

	return ret;

}
@@ -275,12 +276,13 @@ static int run_delalloc_range(struct inode *inode, u64 start, u64 end) 
int btrfs_set_bit_hook(struct inode *inode, u64 start, u64 end,

		       unsigned long old, unsigned long bits)

{

	unsigned long flags;

	if (!(old & EXTENT_DELALLOC) && (bits & EXTENT_DELALLOC)) {

		struct btrfs_root *root = BTRFS_I(inode)->root;

		spin_lock(&root->fs_info->delalloc_lock);

		spin_lock_irqsave(&root->fs_info->delalloc_lock, flags);

		BTRFS_I(inode)->delalloc_bytes += end - start + 1;

		root->fs_info->delalloc_bytes += end - start + 1;

		spin_unlock(&root->fs_info->delalloc_lock);

		spin_unlock_irqrestore(&root->fs_info->delalloc_lock, flags);

	}

	return 0;

}
@@ -290,7 +292,9 @@ int btrfs_clear_bit_hook(struct inode *inode, u64 start, u64 end, 
{

	if ((old & EXTENT_DELALLOC) && (bits & EXTENT_DELALLOC)) {

		struct btrfs_root *root = BTRFS_I(inode)->root;

		spin_lock(&root->fs_info->delalloc_lock);

		unsigned long flags;



		spin_lock_irqsave(&root->fs_info->delalloc_lock, flags);

		if (end - start + 1 > root->fs_info->delalloc_bytes) {

			printk("warning: delalloc account %Lu %Lu\n",

			       end - start + 1, root->fs_info->delalloc_bytes);
@@ -300,7 +304,7 @@ int btrfs_clear_bit_hook(struct inode *inode, u64 start, u64 end, 
			root->fs_info->delalloc_bytes -= end - start + 1;

			BTRFS_I(inode)->delalloc_bytes -= end - start + 1;

		}

		spin_unlock(&root->fs_info->delalloc_lock);

		spin_unlock_irqrestore(&root->fs_info->delalloc_lock, flags);

	}

	return 0;

}