[haiku-bugs] Re: [Haiku] #6750: chmod is broken for non-superuser
- From: "bonefish" <trac@xxxxxxxxxxxx>
- Date: Sat, 06 Nov 2010 13:20:49 -0000
#6750: chmod is broken for non-superuser
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Reporter: grahamh | Owner: axeld
Type: bug | Status: new
Priority: normal | Milestone: R1
Component: File Systems/BFS | Version: R1/Development
Resolution: | Keywords: chmod, write_stat
Blocked By: | Has a Patch: 1
Platform: All | Blocking:
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Comment (by bonefish):
Replying to [comment:15 grahamh]:
> Need to be a bit careful if making this kind of thing common. Most
filesystems will need to do this, but not all of them. (For example I
don't think that MSDOS filesystems have a concept of "file owner".) I
would guess that's why it's not done in the VFS layer?
File systems that don't have those features should simply pretend they do
and emulate the behavior accordingly. The main reasons for leaving
permission checks to the file system implementation are:
1. Performance. The VFS could use the read_stat() and/or access() hooks
to do that before invoking the FS hook that performs the actual operation,
but that would have more overhead than the FS doing it.
1. Atomicity (more importantly). Only the FS can make sure the check and
the actual operation are performed atomically, since the locks for the
volume/node are not known outside the FS implementation.
--
Ticket URL: <http://dev.haiku-os.org/ticket/6750#comment:16>
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