Re: [PATCH] vfs: Add a trace point in the mark_inode_dirty function

Li Zefan
2009-11-11T02:34:51Z

> +/*
> + * Tracepoint for dirtying an inode:
> + */
> +TRACE_EVENT(dirty_inode,
> +
> + TP_PROTO(struct inode *inode, struct task_struct *task),
> +
> + TP_ARGS(inode, task),
> +
> + TP_STRUCT__entry(
> + __array( char, comm, TASK_COMM_LEN )
> + __field( pid_t, pid )
> + __array( char, dev, 16 )
> + __array( char, file, 32 )
> + ),
> +
> + TP_fast_assign(
> + if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) {
> + struct dentry *dentry;
> + const char *name = "?";
> +
> + dentry = d_find_alias(inode);
> + if (dentry) {
> + spin_lock(&dentry->d_lock);
> + name = (const char *) dentry->d_name.name;
> + }
> +
> + memcpy(__entry->comm, task->comm, TASK_COMM_LEN);
> + __entry->pid = task->pid;
> + strlcpy(__entry->file, name, 32);
> + strlcpy(__entry->dev, inode->i_sb->s_id, 16);
> +
> + if (dentry) {
> + spin_unlock(&dentry->d_lock);
> + dput(dentry);
> + }
> + }

This will leave __entry->comm, __entry->file and __entry->dev
uninitialized in the "else" case..

And is there any reason that we have to use __array() but can't
use __string()?

> + ),
> +
> + TP_printk("task=%i (%s) file=%s dev=%s",
> + __entry->pid, __entry->comm, __entry->file, __entry->dev)
> +);
> +
> +#endif /* _TRACE_VFS_H */