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Commit Graph

10 Commits

Author SHA1 Message Date
Marcel Moolenaar
1467117a05 If we can't open the file, skip devclose() for the exclusive_file_system
case. We never called devopen(), so we know there's nothing to close.
2015-10-08 17:59:05 +00:00
Marcel Moolenaar
f2fb1d4531 Provide a means for loaders to control which file system to use. This
to counteract the default behaviour of always trying each and every
file system until one succeeds, or the open fails. The problem with the
loader is that we've implemented features based on this behavior. The
handling of compressed files is a good example of this. However, it is
in general highly undesirable to not have a one-time probe (or taste
in the geom lingo), followed by something similar to a mount whenever
we (first) read from a device. Everytime we go to the same device, we
can reasonably assume it (still) has the same file system. For file
systems that need to do far more that a trivial read of a super block,
not having something similar to a mount operation is disastrous from
a performance (and thus usability) perspective.

But, again, since we've implemented features based on this stateless
approach, things can get complicated quickly if and when we want to
change this. And yet, we sometimes do need stateful behaviour.

For this reason, this change simply introduces exclusive_file_system.
When set to the fsops of the file system to use, the open call will
only try this file system. Setting it to NULL restores the default
behaviour. It's a low-cost (low-brow?) approach to provide enough
control without re-implementing the guts of the loader.

A good example of when this is useful is when we're trying to load
files out of a container (say, a software packaga) that itself lives
on a file system or is fetched over the network. While opening the
container can be done in the normal stateless manner, once it is
opened, subsequent opens should only consider the container.

Obtained from:	Juniper Networks, Inc.
2014-07-30 16:08:16 +00:00
Christian Brueffer
a79d48f537 Initialize f_rabuf in the raw device case. A subsequent close()
later on would try to free it, leading to a crash.

PR:		93998
Submitted by:	neel
MFC after:	1 week
2009-10-28 14:13:45 +00:00
Warner Losh
ee7093a640 Remove California Regent's clause 3, per letter 2007-01-09 01:02:06 +00:00
Matthew Dillon
e74b6a84ce Add __FBSDID()s to libstand 2001-09-30 22:28:01 +00:00
Paul Saab
4d3367540c Backout last commit. It was wrong.. *sigh* 2000-09-10 01:17:47 +00:00
Paul Saab
6b9a6703e9 include string.h to silence a warning. 2000-09-10 01:10:15 +00:00
Mike Smith
ba20acfdb2 Implement readahead buffering for non-raw files. This drastically improves
the efficiency of byte-by-byte read operations on filesystems not already
supported by the block cache (especially NFS).

This should be a welcome change for users booting via PXE, as the loader
now reads its startup files almost instantly, instead of taking tens of
seconds.
2000-09-05 09:52:50 +00:00
Doug Rabson
f069bf5a2c * Enable old UFS compatibility code for booting from Digital Unix formatted
disks.
* Fix a whole raft of warnings, printf and otherwise.
* Make zalloc work for alpha (just a case of using the right typedef).
* Add some (disabled) malloc debug printing to stand.h.
1998-09-26 10:48:50 +00:00
Mike Smith
6b4f575cb1 This is libstand; a support library for standalone executables (eg. bootstrap
modules).
Obtained from: NetBSD, with some architectural changes and many additions.
1998-08-20 08:19:55 +00:00