btrfs: make the init of static elements in fs_info separate

In adding things like eb leak checking and root leak checking there were
a lot of weird corner cases that come from the fact that

  1) We do not init the fs_info until we get to open_ctree time in the
     normal case and

  2) The test infrastructure half-init's the fs_info for things that it
     needs.

This makes it really annoying to make changes because you have to add
init in two different places, have special cases for testing fs_info's
that may not have certain things initialized, and cases for fs_info's
that didn't make it to open_ctree and thus are not fully set up.

Fix this by extracting out the non-allocating init of the fs info into
it's own public function and use that to make sure we're all getting
consistent views of an allocated fs_info.

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

1 files changed, 5 insertions, 2 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index f1ad1189c930..d6629e693a96 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1522,14 +1522,17 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
 	/*
 	 * Setup a dummy root and fs_info for test/set super.  This is because
 	 * we don't actually fill this stuff out until open_ctree, but we need
-	 * it for searching for existing supers, so this lets us do that and
-	 * then open_ctree will properly initialize everything later.
+	 * then open_ctree will properly initialize the file system specific
+	 * settings later.  btrfs_init_fs_info initializes the static elements
+	 * of the fs_info (locks and such) to make cleanup easier if we find a
+	 * superblock with our given fs_devices later on at sget() time.
 	 */
 	fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
 	if (!fs_info) {
 		error = -ENOMEM;
 		goto error_sec_opts;
 	}
+	btrfs_init_fs_info(fs_info);
 
 	fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
 	fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);