diff mbox series

[v5,03/10] btrfs: create free space tree on ro->rw remount

Message ID c54b8b303c2b029e2125582d4d80a350dab8d94e.1603828718.git.boris@bur.io
State New, archived
Headers show
Series [v5,01/10] btrfs: lift rw mount setup from mount and remount | expand

Commit Message

Boris Burkov Oct. 27, 2020, 9:07 p.m. UTC
When a user attempts to remount a btrfs filesystem with
'mount -o remount,space_cache=v2', that operation silently succeeds.
Unfortunately, this is misleading, because the remount does not create
the free space tree. /proc/mounts will incorrectly show space_cache=v2,
but on the next mount, the file system will revert to the old
space_cache.

For now, we handle only the easier case, where the existing mount is
read-only and the new mount is read-write. In that case, we can create
the free space tree without contending with the block groups changing
as we go.

Signed-off-by: Boris Burkov <boris@bur.io>
---
 fs/btrfs/disk-io.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)
diff mbox series

Patch

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 95b9cc5db397..5fe0a2640c8a 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2842,6 +2842,17 @@  int btrfs_mount_rw(struct btrfs_fs_info *fs_info)
 		goto out;
 	}
 
+	if (btrfs_test_opt(fs_info, FREE_SPACE_TREE) &&
+	    !btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
+		btrfs_info(fs_info, "creating free space tree");
+		ret = btrfs_create_free_space_tree(fs_info);
+		if (ret) {
+			btrfs_warn(fs_info,
+				"failed to create free space tree: %d", ret);
+			goto out;
+		}
+	}
+
 	ret = btrfs_resume_balance_async(fs_info);
 	if (ret)
 		goto out;
@@ -3304,18 +3315,6 @@  int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 		}
 	}
 
-	if (btrfs_test_opt(fs_info, FREE_SPACE_TREE) &&
-	    !btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
-		btrfs_info(fs_info, "creating free space tree");
-		ret = btrfs_create_free_space_tree(fs_info);
-		if (ret) {
-			btrfs_warn(fs_info,
-				"failed to create free space tree: %d", ret);
-			close_ctree(fs_info);
-			return ret;
-		}
-	}
-
 	btrfs_discard_resume(fs_info);
 	ret = btrfs_mount_rw(fs_info);
 	if (ret) {