btrfs: refactor btrfs_drop_extents() to make it easier to extend

There are many arguments for __btrfs_drop_extents() and its wrapper
btrfs_drop_extents(), which makes it hard to add more arguments to it and
requires changing every caller. I have added a couple myself back in 2014
commit 1acae57b161e ("Btrfs: faster file extent item replace operations")
and therefore know firsthand that it is a bit cumbersome to add additional
arguments to these functions.

Since I will need to add more arguments in a subsequent bug fix, this
change is preparatory work and adds a data structure that holds all the
arguments, for both input and output, that are passed to this function,
with some comments in the structure's definition mentioning what each
field is and how it relates to other fields.

Callers of this function need only to zero out the content of the
structure and setup only the fields they need. This also removes the
need to have both __btrfs_drop_extents() and btrfs_drop_extents(), so
now we have a single function named btrfs_drop_extents() that takes a
pointer to this new data structure (struct btrfs_drop_extents_args).

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 26 insertions, 15 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index d2ef8308ad0a..25764de68b92 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -202,7 +202,7 @@ static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
  * no overlapping inline items exist in the btree
  */
 static int insert_inline_extent(struct btrfs_trans_handle *trans,
-				struct btrfs_path *path, int extent_inserted,
+				struct btrfs_path *path, bool extent_inserted,
 				struct btrfs_root *root, struct inode *inode,
 				u64 start, size_t size, size_t compressed_size,
 				int compress_type,
@@ -316,6 +316,7 @@ static noinline int cow_file_range_inline(struct btrfs_inode *inode, u64 start,
 					  int compress_type,
 					  struct page **compressed_pages)
 {
+	struct btrfs_drop_extents_args drop_args = { 0 };
 	struct btrfs_root *root = inode->root;
 	struct btrfs_fs_info *fs_info = root->fs_info;
 	struct btrfs_trans_handle *trans;
@@ -326,8 +327,6 @@ static noinline int cow_file_range_inline(struct btrfs_inode *inode, u64 start,
 	u64 data_len = inline_len;
 	int ret;
 	struct btrfs_path *path;
-	int extent_inserted = 0;
-	u32 extent_item_size;
 
 	if (compressed_size)
 		data_len = compressed_size;
@@ -353,16 +352,20 @@ static noinline int cow_file_range_inline(struct btrfs_inode *inode, u64 start,
 	}
 	trans->block_rsv = &inode->block_rsv;
 
+	drop_args.path = path;
+	drop_args.start = start;
+	drop_args.end = aligned_end;
+	drop_args.drop_cache = true;
+	drop_args.replace_extent = true;
+
 	if (compressed_size && compressed_pages)
-		extent_item_size = btrfs_file_extent_calc_inline_size(
+		drop_args.extent_item_size = btrfs_file_extent_calc_inline_size(
 		   compressed_size);
 	else
-		extent_item_size = btrfs_file_extent_calc_inline_size(
+		drop_args.extent_item_size = btrfs_file_extent_calc_inline_size(
 		    inline_len);
 
-	ret = __btrfs_drop_extents(trans, root, inode, path, start, aligned_end,
-				   NULL, 1, 1, extent_item_size,
-				   &extent_inserted);
+	ret = btrfs_drop_extents(trans, root, inode, &drop_args);
 	if (ret) {
 		btrfs_abort_transaction(trans, ret);
 		goto out;
@@ -370,7 +373,7 @@ static noinline int cow_file_range_inline(struct btrfs_inode *inode, u64 start,
 
 	if (isize > actual_end)
 		inline_len = min_t(u64, isize, actual_end);
-	ret = insert_inline_extent(trans, path, extent_inserted,
+	ret = insert_inline_extent(trans, path, drop_args.extent_inserted,
 				   root, &inode->vfs_inode, start,
 				   inline_len, compressed_size,
 				   compress_type, compressed_pages);
@@ -2568,7 +2571,7 @@ static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
 	u64 disk_bytenr = btrfs_stack_file_extent_disk_bytenr(stack_fi);
 	u64 num_bytes = btrfs_stack_file_extent_num_bytes(stack_fi);
 	u64 ram_bytes = btrfs_stack_file_extent_ram_bytes(stack_fi);
-	int extent_inserted = 0;
+	struct btrfs_drop_extents_args drop_args = { 0 };
 	int ret;
 
 	path = btrfs_alloc_path();
@@ -2584,13 +2587,16 @@ static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
 	 * the caller is expected to unpin it and allow it to be merged
 	 * with the others.
 	 */
-	ret = __btrfs_drop_extents(trans, root, inode, path, file_pos,
-				   file_pos + num_bytes, NULL, 0,
-				   1, sizeof(*stack_fi), &extent_inserted);
+	drop_args.path = path;
+	drop_args.start = file_pos;
+	drop_args.end = file_pos + num_bytes;
+	drop_args.replace_extent = true;
+	drop_args.extent_item_size = sizeof(*stack_fi);
+	ret = btrfs_drop_extents(trans, root, inode, &drop_args);
 	if (ret)
 		goto out;
 
-	if (!extent_inserted) {
+	if (!drop_args.extent_inserted) {
 		ins.objectid = btrfs_ino(inode);
 		ins.offset = file_pos;
 		ins.type = BTRFS_EXTENT_DATA_KEY;
@@ -4748,6 +4754,7 @@ static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
 {
 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 	struct btrfs_trans_handle *trans;
+	struct btrfs_drop_extents_args drop_args = { 0 };
 	int ret;
 
 	/*
@@ -4770,7 +4777,11 @@ static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
 	if (IS_ERR(trans))
 		return PTR_ERR(trans);
 
-	ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
+	drop_args.start = offset;
+	drop_args.end = offset + len;
+	drop_args.drop_cache = true;
+
+	ret = btrfs_drop_extents(trans, root, BTRFS_I(inode), &drop_args);
 	if (ret) {
 		btrfs_abort_transaction(trans, ret);
 		btrfs_end_transaction(trans);