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path: root/include/linux/fs_struct.h
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* vfs: move get_fs_root_and_pwd() to single callerLinus Torvalds2013-09-121-11/+0
| | | | | | | | Let's not pollute the include files with inline functions that are only used in a single place. Especially not if we decide we might want to change the semantics of said function to make it more efficient.. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* userns: Don't allow creation if the user is chrootedEric W. Biederman2013-03-271-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Guarantee that the policy of which files may be access that is established by setting the root directory will not be violated by user namespaces by verifying that the root directory points to the root of the mount namespace at the time of user namespace creation. Changing the root is a privileged operation, and as a matter of policy it serves to limit unprivileged processes to files below the current root directory. For reasons of simplicity and comprehensibility the privilege to change the root directory is gated solely on the CAP_SYS_CHROOT capability in the user namespace. Therefore when creating a user namespace we must ensure that the policy of which files may be access can not be violated by changing the root directory. Anyone who runs a processes in a chroot and would like to use user namespace can setup the same view of filesystems with a mount namespace instead. With this result that this is not a practical limitation for using user namespaces. Cc: stable@vger.kernel.org Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Reported-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* constify path_get/path_put and fs_struct.c stuffAl Viro2013-03-011-2/+2
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* kill daemonize()Al Viro2012-11-281-1/+0
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs: fs_struct use seqlockNick Piggin2011-01-071-0/+3
| | | | | | | | | | | | Use a seqlock in the fs_struct to enable us to take an atomic copy of the complete cwd and root paths. Use this in the RCU lookup path to avoid a thread-shared spinlock in RCU lookup operations. Multi-threaded apps may now perform path lookups with scalability matching multi-process apps. Operations such as stat(2) become very scalable for multi-threaded workload. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
* fs: fs_struct rwlock to spinlockNick Piggin2010-08-181-7/+7
| | | | | | | | | | | | | | | | | fs: fs_struct rwlock to spinlock struct fs_struct.lock is an rwlock with the read-side used to protect root and pwd members while taking references to them. Taking a reference to a path typically requires just 2 atomic ops, so the critical section is very small. Parallel read-side operations would have cacheline contention on the lock, the dentry, and the vfsmount cachelines, so the rwlock is unlikely to ever give a real parallelism increase. Replace it with a spinlock to avoid one or two atomic operations in typical path lookup fastpath. Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* vfs: add helpers to get root and pwdMiklos Szeredi2010-08-111-0/+27
| | | | | | | | | | | | Add three helpers that retrieve a refcounted copy of the root and cwd from the supplied fs_struct. get_fs_root() get_fs_pwd() get_fs_root_and_pwd() Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* New locking/refcounting for fs_structAl Viro2009-03-311-5/+3
| | | | | | | | | | | | | | | | * all changes of current->fs are done under task_lock and write_lock of old fs->lock * refcount is not atomic anymore (same protection) * its decrements are done when removing reference from current; at the same time we decide whether to free it. * put_fs_struct() is gone * new field - ->in_exec. Set by check_unsafe_exec() if we are trying to do execve() and only subthreads share fs_struct. Cleared when finishing exec (success and failure alike). Makes CLONE_FS fail with -EAGAIN if set. * check_unsafe_exec() may fail with -EAGAIN if another execve() from subthread is in progress. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Take fs_struct handling to new file (fs/fs_struct.c)Al Viro2009-03-311-0/+2
| | | | | | | | | | Pure code move; two new helper functions for nfsd and daemonize (unshare_fs_struct() and daemonize_fs_struct() resp.; for now - the same code as used to be in callers). unshare_fs_struct() exported (for nfsd, as copy_fs_struct()/exit_fs() used to be), copy_fs_struct() and exit_fs() don't need exports anymore. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Annotate struct fs_struct's usage count restrictionDavid Howells2009-03-281-1/+4
| | | | | | | | | | | Annotate struct fs_struct's usage count to indicate the restrictions upon it. It may not be incremented, except by clone(CLONE_FS), as this affects the check in check_unsafe_exec() in fs/exec.c. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* take init_fs to saner placeAl Viro2008-12-311-6/+0
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* [PATCH] kill altrootAl Viro2008-07-261-2/+1
| | | | | | long overdue... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Make set_fs_{root,pwd} take a struct pathJan Blunck2008-02-141-2/+2
| | | | | | | | | | | In nearly all cases the set_fs_{root,pwd}() calls work on a struct path. Change the function to reflect this and use path_get() here. Signed-off-by: Jan Blunck <jblunck@suse.de> Signed-off-by: Andreas Gruenbacher <agruen@suse.de> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Use struct path in fs_structJan Blunck2008-02-141-4/+2
| | | | | | | | | | * Use struct path in fs_struct. Signed-off-by: Andreas Gruenbacher <agruen@suse.de> Signed-off-by: Jan Blunck <jblunck@suse.de> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Move fs_cachep to linux/fs_struct.hChristoph Lameter2006-12-071-0/+2
| | | | | | | | | | fs_cachep is only used in kernel/exit.c and in kernel/fork.c. It is used to store fs_struct items so it should be placed in linux/fs_struct.h Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds2005-04-161-0/+28
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!