NFS

[Jan Schmidt]

Dobry den,

cituji Network Programming (Sun), 1988, Network File System: Version 2 Protocol
Specification (a doufam, ze moc neporusuju copyright)

	Another problem arises due to the usually stateful open operation.
	Most operating systems check permission at open time, and check that
	the file is open on each read and write request. With stateless servers,
	the server has no idea that the file is open and must do permission
	checking on each read and write call. On a local filesystem, a user
	can open a file and then change the permissions so that no one is
	allowed to touch it, but will still be able to write to the file
	because it is open. On a remote filesystem, the write would fail.
*	To get around this problem, the server's permission checking algorithm
*	should allow the owner of a file to access it regardless of
*	the permission setting.

Nevim, co na to novejsi implementace NFS, ale mely by byt opravdu bezestavove,
tj. zapis by bud nemel jit vubec, nebo by mel jit porad. Otevirani a zavirani
deskriprtoru je interni zalezitosti serveru, tyto deskriptory se nesmeji
zamenovat za deskriptory, ktere jsou poskytovany klientu. Ty se totiz
neoteviraji. K cemu take, kdyz je server bezestavovy.

Radsi se nebudu ptat, co je to za implementaci. Zrovna tu jedna sitova
fackovacka (angl. flame war) skoncila ... :-)

Jan Schmidt
katedra pocitacu FEL CVUT