问题
According to the definition,
A file system filter driver is an optional driver that adds value to or modifies the behavior of a file system. A file system filter driver can filter I/O operations for one or more file systems or file system volumes. Depending on the nature of the driver, filter can mean log, observe, modify, or even prevent.
I want to write a filter driver for Linux which will intercept all read requests to an ext4 partition and redirect a few of them based on some application defined criteria. Googling on filter driver development returns more results (ideas, code snippets) for Windows than on Linux. How can I achieve something similar on Linux? If not a filter driver, then what else can achieve the same effect?
来源：https://stackoverflow.com/questions/42362086/is-there-any-reference-implementation-of-linux-file-system-filter-driver