[PATCH 11/18] btrfs: use a flag to control when to clear the file extent range

[Josef Bacik <josef@toxicpanda.com>]

We only care about updating the file extent range when we are doing a
normal truncation.  We skip this for tree logging currently, but we can
also skip this for eviction as well.  Using a flag makes it more
explicit when we want to do this work.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 fs/btrfs/free-space-cache.c | 1 +
 fs/btrfs/inode-item.c       | 8 ++++----
 fs/btrfs/inode-item.h       | 6 ++++++
 fs/btrfs/inode.c            | 1 +
 4 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index d2f4716f8485..3a6bf361409b 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -294,6 +294,7 @@ int btrfs_truncate_free_space_cache(struct btrfs_trans_handle *trans,
 	struct btrfs_truncate_control control = {
 		.new_size = 0,
 		.min_type = BTRFS_EXTENT_DATA_KEY,
+		.clear_extent_range = true,
 	};
 	struct btrfs_inode *inode = BTRFS_I(vfs_inode);
 	struct btrfs_root *root = inode->root;
diff --git a/fs/btrfs/inode-item.c b/fs/btrfs/inode-item.c
index 79305d646b98..225a5cd3f0ea 100644
--- a/fs/btrfs/inode-item.c
+++ b/fs/btrfs/inode-item.c
@@ -628,11 +628,11 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
 		}
 delete:
 		/*
-		 * We use btrfs_truncate_inode_items() to clean up log trees for
-		 * multiple fsyncs, and in this case we don't want to clear the
-		 * file extent range because it's just the log.
+		 * We only want to clear the file extent range if we're
+		 * modifying the actual inode's mapping, which is just the
+		 * normal truncate path.
 		 */
-		if (root == inode->root) {
+		if (control->clear_extent_range) {
 			ret = btrfs_inode_clear_file_extent_range(inode,
 						  clear_start, clear_len);
 			if (ret) {
diff --git a/fs/btrfs/inode-item.h b/fs/btrfs/inode-item.h
index 0cb16cac07d1..50acee3f4e28 100644
--- a/fs/btrfs/inode-item.h
+++ b/fs/btrfs/inode-item.h
@@ -33,6 +33,12 @@ struct btrfs_truncate_control {
 	 * extents we drop.
 	 */
 	bool skip_ref_updates;
+
+	/*
+	 * IN: true if we need to clear the file extent range for the inode as
+	 * we drop the file extent items.
+	 */
+	bool clear_extent_range;
 };
 
 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 306d410b4db4..45dc4355102a 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8534,6 +8534,7 @@ static int btrfs_truncate(struct inode *inode, bool skip_writeback)
 {
 	struct btrfs_truncate_control control = {
 		.min_type = BTRFS_EXTENT_DATA_KEY,
+		.clear_extent_range = true,
 	};
 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 	struct btrfs_root *root = BTRFS_I(inode)->root;
-- 
2.26.3