This patch modifies the VFS setxattr, getxattr, and listxattr code to fall
back to the security module for security xattrs if the filesystem does not
support xattrs natively. This allows security modules to export the incore
inode security label information to userspace even if the filesystem does
not provide xattr storage, and eliminates the need to individually patch
various pseudo filesystem types to provide such access. The patch removes
the existing xattr code from devpts and tmpfs as it is then no longer
needed.
The patch restructures the code flow slightly to reduce duplication between
the normal path and the fallback path, but this should only have one
user-visible side effect - a program may get -EACCES rather than
-EOPNOTSUPP if policy denied access but the filesystem didn't support the
operation anyway. Note that the post_setxattr hook call is not needed in
the fallback case, as the inode_setsecurity hook call handles the incore
inode security state update directly. In contrast, we do call fsnotify in
both cases.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
inotify is intended to correct the deficiencies of dnotify, particularly
its inability to scale and its terrible user interface:
* dnotify requires the opening of one fd per each directory
that you intend to watch. This quickly results in too many
open files and pins removable media, preventing unmount.
* dnotify is directory-based. You only learn about changes to
directories. Sure, a change to a file in a directory affects
the directory, but you are then forced to keep a cache of
stat structures.
* dnotify's interface to user-space is awful. Signals?
inotify provides a more usable, simple, powerful solution to file change
notification:
* inotify's interface is a system call that returns a fd, not SIGIO.
You get a single fd, which is select()-able.
* inotify has an event that says "the filesystem that the item
you were watching is on was unmounted."
* inotify can watch directories or files.
Inotify is currently used by Beagle (a desktop search infrastructure),
Gamin (a FAM replacement), and other projects.
See Documentation/filesystems/inotify.txt.
Signed-off-by: Robert Love <rml@novell.com>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Stephen Smalley