Does VFS cache individual files? Is the linker involved?

[Magnus Sundberg <Magnus.Sundberg@dican.se>]

Dear sirs,

QUESTION:
Does VFS cache the content of a file?

Does VFS consult memory instead of disk, when accessing a file that is
already linked to a process that is running?


RELATED INFORMATION:
Operating system RedHat 7.1, kernel 2.4.3-12 (from RedHat RPM)
My webserver runs tripwire for integrity test of critical files.

One night, when the PHP runtime of apache had crashed, tripwire reported
checksum error of
/usr/lib/apache/libphp4.so
The next night, when apache was restarted, there where no checksum
errors of the file.

I have seen checksum errors of /lib/libc-2.2.2.so, rpm also reported md5
checksum error when I
used rpm to verify the installation of glibc.

Thank you for your time reading this

regards,

Magnus Sundberg