Btrfs: Dir fsync optimizations
Drop i_mutex during the commit
Don't bother doing the fsync at all unless the dir is marked as dirtied
and needing fsync in this transaction. For directories, this means
that someone has unlinked a file from the dir without fsyncing the
file.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 84ecf3a..58b329d 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1061,7 +1061,9 @@
}
mutex_unlock(&root->fs_info->trans_mutex);
+ root->fs_info->tree_log_batch++;
filemap_fdatawait(inode->i_mapping);
+ root->fs_info->tree_log_batch++;
/*
* ok we haven't committed the transaction yet, lets do a commit
@@ -1076,14 +1078,29 @@
}
ret = btrfs_log_dentry_safe(trans, root, file->f_dentry);
- if (ret < 0)
+ if (ret < 0) {
goto out;
+ }
+
+ /* we've logged all the items and now have a consistent
+ * version of the file in the log. It is possible that
+ * someone will come in and modify the file, but that's
+ * fine because the log is consistent on disk, and we
+ * have references to all of the file's extents
+ *
+ * It is possible that someone will come in and log the
+ * file again, but that will end up using the synchronization
+ * inside btrfs_sync_log to keep things safe.
+ */
+ mutex_unlock(&file->f_dentry->d_inode->i_mutex);
+
if (ret > 0) {
ret = btrfs_commit_transaction(trans, root);
} else {
btrfs_sync_log(trans, root);
ret = btrfs_end_transaction(trans, root);
}
+ mutex_lock(&file->f_dentry->d_inode->i_mutex);
out:
return ret > 0 ? EIO : ret;
}