NFS

[Jan Kasprzak]

	Dobry den,
:
: cituji Network Programming (Sun), 1988, Network File System: Version 2 Protocol
: Specification (a doufam, ze moc neporusuju copyright)
:
	Diky za odpoved. Chtel bych se zeptat, jestli lze citovanou
specifikaci nekde sehnat, nejlepe v elektronicke podobe?

: 	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.

	Tomu se ale (aspon pokud to spravne chapu) nerika descriptory,
ale filehandles.
:
: Radsi se nebudu ptat, co je to za implementaci. Zrovna tu jedna sitova
: fackovacka (angl. flame war) skoncila ... :-)
:
	Ja jsem to tam psal (aspon doufam): Klient je Win95+OnNet 2.0
od FTP software, server je Linux (nfs-server 2.1 nebo tak nejak).

	Tak ted nevim, co mam udelat: Zakazat na nfs-serveru
open( ..., O_RDWR|O_CREAT, pristupova_prava_bez_zapisu),
nebo naopak povolit vlastnikovi zapis do vsech jeho souboru?
Asi udelam to druhe. Ale je to dost neciste.

-Yenya

P.S.: Podobny problem u NFS nastava tam, kde vytvorite docasny soubor,
	pak jej unlink()ujete a pak pouzivate. Jak tohleto nfs-servery
	resi? Videl jsem nejaky bastl typu prejmenovani tohoto souboru
	na .nfs_XXXXX a podobne.

--
Jan "Yenya" Kasprzak  |  mailto:kas at muni.cz  |   http://www.fi.muni.cz/~kas/
[[[[ Student of Informatics, Faculty of Informatics, Masaryk University ]]]]
[[[[      Czech Linux Homepage:  http://www.fi.muni.cz/~kas/linux/      ]]]]
``I _like_ using goto's every once in a while:  it can often mess up the gcc
optimizer just enough to get better code out of it.''       --Linus Torvalds