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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: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Filipe Manana 2021-01-27 10:34:56 +00:00 committed by David Sterba
parent e593e54ed1
commit ab12313a9f
1 changed files with 33 additions and 2 deletions
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35
fs/btrfs/tree-log.c
View File

@ -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)