Commit ab12313a authored by Filipe Manana's avatar Filipe Manana Committed by David Sterba
Browse files

btrfs: avoid logging new ancestor inodes when logging new inode 



When we fsync a new file, created in the current transaction, we check
all its ancestor inodes and always log them if they were created in the
current transaction - even if we have already logged them before, which
is a waste of time.

So avoid logging new ancestor inodes if they were already logged before
and have no xattrs added/updated/removed since they were last logged.

This patch is part of a patchset comprised of the following patches:

  btrfs: remove unnecessary directory inode item update when deleting dir entry
  btrfs: stop setting nbytes when filling inode item for logging
  btrfs: avoid logging new ancestor inodes when logging new inode
  btrfs: skip logging directories already logged when logging all parents
  btrfs: skip logging inodes already logged when logging new entries
  btrfs: remove unnecessary check_parent_dirs_for_sync()
  btrfs: make concurrent fsyncs wait less when waiting for a transaction commit

Performance results, after applying all patches, are mentioned in the
change log of the last patch.

Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent e593e54e

fs/btrfs/tree-log.c

+33 −2
Original line number Diff line number Diff line
@@ -5272,6 +5272,7 @@ static int btrfs_log_inode(struct btrfs_trans_handle *trans, 
	if (S_ISDIR(inode->vfs_inode.i_mode)) {

		int max_key_type = BTRFS_DIR_LOG_INDEX_KEY;



		clear_bit(BTRFS_INODE_COPY_EVERYTHING, &inode->runtime_flags);

		if (inode_only == LOG_INODE_EXISTS)

			max_key_type = BTRFS_XATTR_ITEM_KEY;

		ret = drop_objectid_items(trans, log, path, ino, max_key_type);
@@ -5520,6 +5521,34 @@ static noinline int check_parent_dirs_for_sync(struct btrfs_trans_handle *trans, 
	return ret;

}



/*

 * Check if we need to log an inode. This is used in contexts where while

 * logging an inode we need to log another inode (either that it exists or in

 * full mode). This is used instead of btrfs_inode_in_log() because the later

 * requires the inode to be in the log and have the log transaction committed,

 * while here we do not care if the log transaction was already committed - our

 * caller will commit the log later - and we want to avoid logging an inode

 * multiple times when multiple tasks have joined the same log transaction.

 */

static bool need_log_inode(struct btrfs_trans_handle *trans,

			   struct btrfs_inode *inode)

{

	/*

	 * If this inode does not have new/updated/deleted xattrs since the last

	 * time it was logged and is flagged as logged in the current transaction,

	 * we can skip logging it. As for new/deleted names, those are updated in

	 * the log by link/unlink/rename operations.

	 * In case the inode was logged and then evicted and reloaded, its

	 * logged_trans will be 0, in which case we have to fully log it since

	 * logged_trans is a transient field, not persisted.

	 */

	if (inode->logged_trans == trans->transid &&

	    !test_bit(BTRFS_INODE_COPY_EVERYTHING, &inode->runtime_flags))

		return false;



	return true;

}



struct btrfs_dir_list {

	u64 ino;

	struct list_head list;
@@ -5848,7 +5877,8 @@ static int log_new_ancestors(struct btrfs_trans_handle *trans, 
		if (IS_ERR(inode))

			return PTR_ERR(inode);



		if (BTRFS_I(inode)->generation >= trans->transid)

		if (BTRFS_I(inode)->generation >= trans->transid &&

		    need_log_inode(trans, BTRFS_I(inode)))

			ret = btrfs_log_inode(trans, root, BTRFS_I(inode),

					      LOG_INODE_EXISTS, ctx);

		btrfs_add_delayed_iput(inode);
@@ -5902,7 +5932,8 @@ static int log_new_ancestors_fast(struct btrfs_trans_handle *trans, 
		if (root != inode->root)

			break;



		if (inode->generation >= trans->transid) {

		if (inode->generation >= trans->transid &&

		    need_log_inode(trans, inode)) {

			ret = btrfs_log_inode(trans, root, inode,

					      LOG_INODE_EXISTS, ctx);

			if (ret)