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Commit ee6e6504 authored by Chris Mason's avatar Chris Mason
Browse files

Add a per-inode lock around btrfs_drop_extents 



btrfs_drop_extents is always called with a range lock held on the inode.
But, it may operate on extents outside that range as it drops and splits
them.

This patch adds a per-inode mutex that is held while calling
btrfs_drop_extents and while inserting new extents into the tree.  It
prevents races from two procs working against adjacent ranges in the tree.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent ba1da2f4

fs/btrfs/btrfs_inode.h

+1 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ struct btrfs_inode { 
	struct extent_io_tree io_tree;

	struct extent_io_tree io_failure_tree;

	struct mutex csum_mutex;

	struct mutex extent_mutex;

	struct inode vfs_inode;

	struct btrfs_ordered_inode_tree ordered_tree;

fs/btrfs/extent-tree.c

+2 −0
Original line number Diff line number Diff line
@@ -1671,6 +1671,8 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans, 
	ret = __free_extent(trans, root, bytenr, num_bytes, root_objectid,

			    ref_generation, owner_objectid, owner_offset,

			    pin, pin == 0);



	finish_current_insert(trans, root->fs_info->extent_root);

	pending_ret = del_pending_extents(trans, root->fs_info->extent_root);

	return ret ? ret : pending_ret;

}

fs/btrfs/file.c

+8 −0
Original line number Diff line number Diff line
@@ -242,6 +242,7 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans, 
	u64 end_of_last_block;

	u64 end_pos = pos + write_bytes;

	u64 inline_size;

	int did_inline = 0;

	loff_t isize = i_size_read(inode);



	start_pos = pos & ~((u64)root->sectorsize - 1);
@@ -275,6 +276,7 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans, 
		if (hole_size > 0) {

			btrfs_wait_ordered_range(inode, last_pos_in_file,

						 last_pos_in_file + hole_size);

			mutex_lock(&BTRFS_I(inode)->extent_mutex);

			err = btrfs_drop_extents(trans, root, inode,

						 last_pos_in_file,

						 last_pos_in_file + hole_size,
@@ -289,6 +291,7 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans, 
						       0, 0, hole_size, 0);

			btrfs_drop_extent_cache(inode, last_pos_in_file,

					last_pos_in_file + hole_size -1);

			mutex_unlock(&BTRFS_I(inode)->extent_mutex);

			btrfs_check_file(root, inode);

		}

		if (err)
@@ -321,6 +324,7 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans, 
		/* step one, delete the existing extents in this range */

		aligned_end = (pos + write_bytes + root->sectorsize - 1) &

			~((u64)root->sectorsize - 1);

		mutex_lock(&BTRFS_I(inode)->extent_mutex);

		err = btrfs_drop_extents(trans, root, inode, start_pos,

					 aligned_end, aligned_end, &hint_byte);

		if (err)
@@ -332,9 +336,13 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans, 
					   inline_size, pages, 0, num_pages);

		btrfs_drop_extent_cache(inode, start_pos, aligned_end - 1);

		BUG_ON(err);

		mutex_unlock(&BTRFS_I(inode)->extent_mutex);

		did_inline = 1;

	}

	if (end_pos > isize) {

		i_size_write(inode, end_pos);

		if (did_inline)

			BTRFS_I(inode)->disk_i_size = end_pos;

		btrfs_update_inode(trans, root, inode);

	}

failed:

fs/btrfs/inode.c

+10 −0
Original line number Diff line number Diff line
@@ -516,6 +516,8 @@ int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end, 
					  trans->transid, inode->i_ino,

					  ordered_extent->file_offset, &ins);

	BUG_ON(ret);



	mutex_lock(&BTRFS_I(inode)->extent_mutex);

	ret = btrfs_drop_extents(trans, root, inode,

				 ordered_extent->file_offset,

				 ordered_extent->file_offset +
@@ -531,6 +533,8 @@ int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end, 
	btrfs_drop_extent_cache(inode, ordered_extent->file_offset,

				ordered_extent->file_offset +

				ordered_extent->len - 1);

	mutex_unlock(&BTRFS_I(inode)->extent_mutex);



	inode->i_blocks += ordered_extent->len >> 9;

	unlock_extent(io_tree, ordered_extent->file_offset,

		    ordered_extent->file_offset + ordered_extent->len - 1,
@@ -1399,6 +1403,7 @@ static int btrfs_setattr(struct dentry *dentry, struct iattr *attr) 


		trans = btrfs_start_transaction(root, 1);

		btrfs_set_trans_block_group(trans, inode);

		mutex_lock(&BTRFS_I(inode)->extent_mutex);

		err = btrfs_drop_extents(trans, root, inode,

					 hole_start, block_end, hole_start,

					 &alloc_hint);
@@ -1412,6 +1417,7 @@ static int btrfs_setattr(struct dentry *dentry, struct iattr *attr) 
						(u64)-1);

			btrfs_check_file(root, inode);

		}

		mutex_unlock(&BTRFS_I(inode)->extent_mutex);

		btrfs_end_transaction(trans, root);

		unlock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);

		if (err)
@@ -1578,6 +1584,7 @@ static int btrfs_init_locked_inode(struct inode *inode, void *p) 
			     inode->i_mapping, GFP_NOFS);

	btrfs_ordered_inode_tree_init(&BTRFS_I(inode)->ordered_tree);

	mutex_init(&BTRFS_I(inode)->csum_mutex);

	mutex_init(&BTRFS_I(inode)->extent_mutex);

	return 0;

}
@@ -1880,6 +1887,7 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans, 
			     inode->i_mapping, GFP_NOFS);

	btrfs_ordered_inode_tree_init(&BTRFS_I(inode)->ordered_tree);

	mutex_init(&BTRFS_I(inode)->csum_mutex);

	mutex_init(&BTRFS_I(inode)->extent_mutex);

	BTRFS_I(inode)->delalloc_bytes = 0;

	BTRFS_I(inode)->disk_i_size = 0;

	BTRFS_I(inode)->root = root;
@@ -2105,6 +2113,7 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry, 
		extent_io_tree_init(&BTRFS_I(inode)->io_failure_tree,

				     inode->i_mapping, GFP_NOFS);

		mutex_init(&BTRFS_I(inode)->csum_mutex);

		mutex_init(&BTRFS_I(inode)->extent_mutex);

		BTRFS_I(inode)->delalloc_bytes = 0;

		BTRFS_I(inode)->disk_i_size = 0;

		BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
@@ -3079,6 +3088,7 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry, 
		extent_io_tree_init(&BTRFS_I(inode)->io_failure_tree,

				     inode->i_mapping, GFP_NOFS);

		mutex_init(&BTRFS_I(inode)->csum_mutex);

		mutex_init(&BTRFS_I(inode)->extent_mutex);

		BTRFS_I(inode)->delalloc_bytes = 0;

		BTRFS_I(inode)->disk_i_size = 0;

		BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;