[13/18] btrfs: remove roots ulist when checking data extent sharedness

Commit Message

Filipe Manana Oct. 10, 2022, 10:22 a.m. UTC

From: Filipe Manana <[e-mail]>

Currently btrfs_is_data_extent_shared() is passing a ulist for the roots
argument of find_parent_nodes(), however it does not use that ulist for
anything and for this context that list always ends up with at most one
element.

Since find_parent_nodes() is able to deal with a NULL ulist for its roots
argument, make btrfs_is_data_extent_shared() pass it NULL and avoid the
burden of allocating memory for the unnused roots ulist, initializing it,
releasing it and allocating one struct ulist_node for it during the call
to find_parent_nodes().

Signed-off-by: Filipe Manana <[e-mail]>
---
 fs/btrfs/backref.c | 6 +-----
 fs/btrfs/backref.h | 1 -
 2 files changed, 1 insertion(+), 6 deletions(-)

Patch

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index e71e2f208cc5..c2ec132c2a9c 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1637,7 +1637,6 @@  struct btrfs_backref_share_check_ctx *btrfs_alloc_backref_share_check_ctx(void)
 		return NULL;
 
 	ulist_init(&ctx->refs);
-	ulist_init(&ctx->roots);
 
 	return ctx;
 }
@@ -1648,7 +1647,6 @@  void btrfs_free_backref_share_ctx(struct btrfs_backref_share_check_ctx *ctx)
 		return;
 
 	ulist_release(&ctx->refs);
-	ulist_release(&ctx->roots);
 	kfree(ctx);
 }
 
@@ -1690,7 +1688,6 @@  int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr,
 	};
 	int level;
 
-	ulist_init(&ctx->roots);
 	ulist_init(&ctx->refs);
 
 	trans = btrfs_join_transaction_nostart(root);
@@ -1714,7 +1711,7 @@  int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr,
 		bool cached;
 
 		ret = find_parent_nodes(trans, fs_info, bytenr, elem.seq, &ctx->refs,
-					&ctx->roots, NULL, &shared, false);
+					NULL, NULL, &shared, false);
 		if (ret == BACKREF_FOUND_SHARED) {
 			/* this is the only condition under which we return 1 */
 			ret = 1;
@@ -1781,7 +1778,6 @@  int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr,
 		up_read(&fs_info->commit_root_sem);
 	}
 out:
-	ulist_release(&ctx->roots);
 	ulist_release(&ctx->refs);
 	return ret;
 }
diff --git a/fs/btrfs/backref.h b/fs/btrfs/backref.h
index 8da0ba6b94a4..5f468f0defda 100644
--- a/fs/btrfs/backref.h
+++ b/fs/btrfs/backref.h
@@ -26,7 +26,6 @@  struct btrfs_backref_shared_cache_entry {
 struct btrfs_backref_share_check_ctx {
 	/* Ulists used during backref walking. */
 	struct ulist refs;
-	struct ulist roots;
 	/*
 	 * A path from a root to a leaf that has a file extent item pointing to
 	 * a given data extent should never exceed the maximum b+tree height.