Commit 5f56406a authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: Fix hole insertion corner cases 



There were a few places that could cause duplicate extent insertion,
this adjusts the code that creates holes to avoid it.

lookup_extent_map is changed to correctly return all of the extents in a
range, even when there are none matching at the start of the range.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent c1e32da6

fs/btrfs/ctree.h

+1 −0
Original line number Diff line number Diff line
@@ -1170,6 +1170,7 @@ int btrfs_update_inode(struct btrfs_trans_handle *trans, 
			      struct inode *inode);

/* file.c */

int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end);

int btrfs_check_file(struct btrfs_root *root, struct inode *inode);

extern struct file_operations btrfs_file_operations;

int btrfs_drop_extents(struct btrfs_trans_handle *trans,

		       struct btrfs_root *root, struct inode *inode,

fs/btrfs/extent_map.c

+36 −9
Original line number Diff line number Diff line
@@ -204,10 +204,12 @@ static struct rb_node *tree_insert(struct rb_root *root, u64 offset, 
}



static struct rb_node *__tree_search(struct rb_root *root, u64 offset,

				   struct rb_node **prev_ret)

				     struct rb_node **prev_ret,

				     struct rb_node **next_ret)

{

	struct rb_node * n = root->rb_node;

	struct rb_node *prev = NULL;

	struct rb_node *orig_prev = NULL;

	struct tree_entry *entry;

	struct tree_entry *prev_entry = NULL;
@@ -223,13 +225,25 @@ static struct rb_node *__tree_search(struct rb_root *root, u64 offset, 
		else

			return n;

	}

	if (!prev_ret)

		return NULL;



	if (prev_ret) {

		orig_prev = prev;

		while(prev && offset > prev_entry->end) {

			prev = rb_next(prev);

			prev_entry = rb_entry(prev, struct tree_entry, rb_node);

		}

		*prev_ret = prev;

		prev = orig_prev;

	}



	if (next_ret) {

		prev_entry = rb_entry(prev, struct tree_entry, rb_node);

		while(prev && offset < prev_entry->start) {

			prev = rb_prev(prev);

			prev_entry = rb_entry(prev, struct tree_entry, rb_node);

		}

		*next_ret = prev;

	}

	return NULL;

}
@@ -237,7 +251,7 @@ static inline struct rb_node *tree_search(struct rb_root *root, u64 offset) 
{

	struct rb_node *prev;

	struct rb_node *ret;

	ret = __tree_search(root, offset, &prev);

	ret = __tree_search(root, offset, &prev, NULL);

	if (!ret)

		return prev;

	return ret;
@@ -248,7 +262,7 @@ static int tree_delete(struct rb_root *root, u64 offset) 
	struct rb_node *node;

	struct tree_entry *entry;



	node = __tree_search(root, offset, NULL);

	node = __tree_search(root, offset, NULL, NULL);

	if (!node)

		return -ENOENT;

	entry = rb_entry(node, struct tree_entry, rb_node);
@@ -314,9 +328,21 @@ struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree, 
{

	struct extent_map *em;

	struct rb_node *rb_node;

	struct rb_node *prev = NULL;

	struct rb_node *next = NULL;



	read_lock_irq(&tree->lock);

	rb_node = tree_search(&tree->map, start);

	rb_node = __tree_search(&tree->map, start, &prev, &next);

	if (!rb_node && prev) {

		em = rb_entry(prev, struct extent_map, rb_node);

		if (em->start <= end && em->end >= start)

			goto found;

	}

	if (!rb_node && next) {

		em = rb_entry(next, struct extent_map, rb_node);

		if (em->start <= end && em->end >= start)

			goto found;

	}

	if (!rb_node) {

		em = NULL;

		goto out;
@@ -330,6 +356,7 @@ struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree, 
		em = NULL;

		goto out;

	}

found:

	atomic_inc(&em->refs);

out:

	read_unlock_irq(&tree->lock);

fs/btrfs/file.c

+77 −1
Original line number Diff line number Diff line
@@ -278,7 +278,7 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans, 
		u64 hole_size;

		u64 mask = root->sectorsize - 1;

		last_pos_in_file = (isize + mask) & ~mask;

		hole_size = (start_pos - last_pos_in_file + mask) & ~mask;

		hole_size = (end_pos - last_pos_in_file + mask) & ~mask;



		if (last_pos_in_file < start_pos) {

			err = btrfs_drop_extents(trans, root, inode,
@@ -293,6 +293,7 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans, 
						       inode->i_ino,

						       last_pos_in_file,

						       0, 0, hole_size);

			btrfs_check_file(root, inode);

		}

		if (err)

			goto failed;
@@ -378,6 +379,80 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end) 
	return 0;

}



int btrfs_check_file(struct btrfs_root *root, struct inode *inode)

{

	return 0;

#if 0

	struct btrfs_path *path;

	struct btrfs_key found_key;

	struct extent_buffer *leaf;

	struct btrfs_file_extent_item *extent;

	u64 last_offset = 0;

	int nritems;

	int slot;

	int found_type;

	int ret;

	int err = 0;

	u64 extent_end = 0;



	path = btrfs_alloc_path();

	ret = btrfs_lookup_file_extent(NULL, root, path, inode->i_ino,

				       last_offset, 0);

	while(1) {

		nritems = btrfs_header_nritems(path->nodes[0]);

		if (path->slots[0] >= nritems) {

			ret = btrfs_next_leaf(root, path);

			if (ret)

				goto out;

			nritems = btrfs_header_nritems(path->nodes[0]);

		}

		slot = path->slots[0];

		leaf = path->nodes[0];

		btrfs_item_key_to_cpu(leaf, &found_key, slot);

		if (found_key.objectid != inode->i_ino)

			break;

		if (found_key.type != BTRFS_EXTENT_DATA_KEY)

			goto out;



		if (found_key.offset != last_offset) {

			WARN_ON(1);

			btrfs_print_leaf(root, leaf);

			printk("inode %lu found offset %Lu expected %Lu\n",

			       inode->i_ino, found_key.offset, last_offset);

			err = 1;

			goto out;

		}

		extent = btrfs_item_ptr(leaf, slot,

					struct btrfs_file_extent_item);

		found_type = btrfs_file_extent_type(leaf, extent);

		if (found_type == BTRFS_FILE_EXTENT_REG) {

			extent_end = found_key.offset +

			     btrfs_file_extent_num_bytes(leaf, extent);

		} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {

			struct btrfs_item *item;

			item = btrfs_item_nr(leaf, slot);

			extent_end = found_key.offset +

			     btrfs_file_extent_inline_len(leaf, item);

			extent_end = (extent_end + root->sectorsize - 1) &

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

		}

		last_offset = extent_end;

		path->slots[0]++;

	}

	if (last_offset < inode->i_size) {

		WARN_ON(1);

		btrfs_print_leaf(root, leaf);

		printk("inode %lu found offset %Lu size %Lu\n", inode->i_ino,

		       last_offset, inode->i_size);

		err = 1;



	}

out:

	btrfs_free_path(path);

	return err;

#endif

}



/*

 * 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
@@ -436,6 +511,7 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans, 
		slot = path->slots[0];

		ret = 0;

		btrfs_item_key_to_cpu(leaf, &key, slot);



		if (key.offset >= end || key.objectid != inode->i_ino) {

			goto out;

		}

fs/btrfs/inode.c

+12 −3
Original line number Diff line number Diff line
@@ -133,6 +133,7 @@ static int cow_file_range(struct inode *inode, u64 start, u64 end) 
		ret = btrfs_insert_file_extent(trans, root, inode->i_ino,

					       start, ins.objectid, ins.offset,

					       ins.offset);

		btrfs_check_file(root, inode);

		num_bytes -= cur_alloc_size;

		alloc_hint = ins.objectid + ins.offset;

		start += cur_alloc_size;
@@ -965,12 +966,18 @@ static int btrfs_setattr(struct dentry *dentry, struct iattr *attr) 
		u64 mask = root->sectorsize - 1;

		u64 pos = (inode->i_size + mask) & ~mask;

		u64 block_end = attr->ia_size | mask;

		u64 hole_start;

		u64 hole_size;

		u64 alloc_hint = 0;



		if (attr->ia_size <= pos)

			goto out;



		if (pos != inode->i_size)

			hole_start = pos + root->sectorsize;

		else

			hole_start = pos;



		mutex_lock(&root->fs_info->fs_mutex);

		err = btrfs_check_free_space(root, 1, 0);

		mutex_unlock(&root->fs_info->fs_mutex);
@@ -980,19 +987,21 @@ static int btrfs_setattr(struct dentry *dentry, struct iattr *attr) 
		btrfs_truncate_page(inode->i_mapping, inode->i_size);



		lock_extent(em_tree, pos, block_end, GFP_NOFS);

		hole_size = (attr->ia_size - pos + mask) & ~mask;

		hole_size = block_end - hole_start;



		mutex_lock(&root->fs_info->fs_mutex);

		trans = btrfs_start_transaction(root, 1);

		btrfs_set_trans_block_group(trans, inode);

		err = btrfs_drop_extents(trans, root, inode,

					 pos, pos + hole_size, pos,

					 pos, block_end, pos,

					 &alloc_hint);



		if (alloc_hint != EXTENT_MAP_INLINE) {

			err = btrfs_insert_file_extent(trans, root,

						       inode->i_ino,

						       pos, 0, 0, hole_size);

						       hole_start, 0, 0,

						       hole_size);

			btrfs_check_file(root, inode);

		}

		btrfs_end_transaction(trans, root);

		mutex_unlock(&root->fs_info->fs_mutex);