:Hi,
:I have a question related to ufs block allocation.
:This problem arises when building picobsd floppy on /dev/fd0
:(ufs with 512/4096 fragments/blocks).
:
:With 3.4, i can easily fill up a disk to 100% occupation.
:
:With -current (20000127), i often fail to write a file (say 53KB)
:on disk even though there _is_ room (say 55KB), and if i split the file
:in multiple parts i can write on that disk even more bytes
:than the original file size.
:
:It looks like there is some change related to the use of file
:system fragments, the feeling i have is that there is
:something like
:
: "if you need to write a full block, don't look for
: fragments but for a full block'.
:
:Does the above sound reasonable, and if so, would it be difficult
:to change the behaviour to make use of fragments if there is
:no better option ?
:
: cheers
: luigi
:-----------------------------------+-------------------------------------
: Luigi RIZZO, [EMAIL PROTECTED] . Dip. di Ing. dell'Informazione
: http://www.iet.unipi.it/~luigi/ . Universita` di Pisa
You can't change this behavior. UFS can only use a file fragment (that
is, typically 1/8 of a full block) at the *END* of a file, not the middle.
Once a fragment has been allocated out of a full block, it cannot be used
as a full block again until the fragment(s) have been deallocated.
This means that there may be free fragments available when there are no
full blocks available, allowing small files to continue to be created
while larger files fail.
-Matt
Matthew Dillon
<[EMAIL PROTECTED]>
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