Regarding the gfp mask "GFP_NOFS"

["Daniel Rodrick" <daniel.rodrick@xxxxxxxxx>]

Hi,

As mentioned in Robert Love's book on Linux kernel development:

"The mask GFP_NOFS to kmalloc specifies that the allocation can block
and can initiate disk I/O, if it must, but will not initiate a
filesystem operation. This is the flag to use in filesystem code when
you cannot start another filesystem operation."

When it came to GFP_NOIO mask that says that no Disk IO should be
initiated to free memory; I could digest that very well since Disk IO
could be initiated to swap a process to disk to free memory.

But I could not understand why and how could a filesystem request be
initiated in order to free memory (the case avoided by GFP_NOFS)?

What am I missing here?

Thanks,

Dan

--
Kernelnewbies: Help each other learn about the Linux kernel.
Archive:       http://mail.nl.linux.org/kernelnewbies/
FAQ:           http://kernelnewbies.org/faq/