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2015-05-15turn user_{path_at,path,lpath,path_dir}() into static inlinesAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15namei: move saved_nd pointer into struct nameidataAl Viro
these guys are always declared next to each other; might as well put the former (pointer to previous instance) into the latter and simplify the calling conventions for {set,restore}_nameidata() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15inline user_path_create()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15inline user_path_parent()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15namei: trim do_last() argumentsAl Viro
now that struct filename is stashed in nameidata we have no need to pass it in Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15namei: stash dfd and name into nameidataAl Viro
fewer arguments to pass around... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15namei: fold path_cleanup() into terminate_walk()Al Viro
they are always called next to each other; moreover, terminate_walk() is more symmetrical that way. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15namei: saner calling conventions for filename_parentat()Al Viro
a) make it reject ERR_PTR() for name b) make it putname(name) on all other failure exits c) make it return name on success again, simplifies the callers Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15namei: saner calling conventions for filename_create()Al Viro
a) make it reject ERR_PTR() for name b) make it putname(name) upon return in all other cases. seriously simplifies the callers... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15namei: shift nameidata down into filename_parentat()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15namei: make filename_lookup() reject ERR_PTR() passed as nameAl Viro
makes for much easier life in callers Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15namei: shift nameidata inside filename_lookup()Al Viro
pass root instead; non-NULL => copy to nd.root and set LOOKUP_ROOT in flags Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15namei: move putname() call into filename_lookup()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15namei: pass the struct path to store the result down into path_lookupat()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15namei: uninline set_root{,_rcu}()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15namei: be careful with mountpoint crossings in follow_dotdot_rcu()Al Viro
Otherwise we are risking a hard error where nonlazy restart would be the right thing to do; it's a very narrow race with mount --move and most of the time it ends up being completely harmless, but it's possible to construct a case when we'll get a bogus hard error instead of falling back to non-lazy walk... For one thing, when crossing _into_ overmount of parent we need to check for mount_lock bumps when we get NULL from __lookup_mnt() as well. For another, and less exotically, we need to make sure that the data fetched in follow_up_rcu() had been consistent. ->mnt_mountpoint is pinned for as long as it is a mountpoint, but we need to check mount_lock after fetching to verify that. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15Documentation: remove outdated information from automount-support.txtNeilBrown
The guidelines for adding automount support to a filesystem in filesystems/automount-support.txt is out or date. filesystems/autofs4.txt contains more current text, so replace the out-of-date content with a reference to that. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15get rid of assorted nameidata-related debrisAl Viro
pointless forward declarations, stale comments Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15lustre: kill unused helperAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15lustre: kill unused macro (LOOKUP_CONTINUE)Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15namei: unlazy_walk() doesn't need to mess with current->fs anymoreAl Viro
now that we have ->root_seq, legitimize_path(&nd->root, nd->root_seq) will do just fine... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15update Documentation/filesystems/ regarding the follow_link/put_link changesAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15namei: handle absolute symlinks without dropping out of RCU modeAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15enable passing fast relative symlinks without dropping out of RCU modeAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15VFS/namei: make the use of touch_atime() in get_link() RCU-safe.NeilBrown
touch_atime is not RCU-safe, and so cannot be called on an RCU walk. However, in situations where RCU-walk makes a difference, the symlink will likely to accessed much more often than it is useful to update the atime. So split out the test of "Does the atime actually need to be updated" into atime_needs_update(), and have get_link() unlazy if it finds that it will need to do that update. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15namei: don't unlazy until get_link()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-15namei: make unlazy_walk and terminate_walk handle nd->stack, add unlazy_linkAl Viro
We are almost done - primitives for leaving RCU mode are aware of nd->stack now, a new primitive for going to non-RCU mode when we have a symlink on hands added. The thing we are heavily relying upon is that *any* unlazy failure will be shortly followed by terminate_walk(), with no access to nameidata in between. So it's enough to leave the things in a state terminate_walk() would cope with. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11namei: store seq numbers in nd->stack[]Al Viro
we'll need them for unlazy_walk() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11new helper: __legitimize_mnt()Al Viro
same as legitimize_mnt(), except that it does *not* drop and regain rcu_read_lock; return values are 0 => grabbed a reference, we are fine 1 => failed, just go away -1 => failed, go away and mntput(bastard) when outside of rcu_read_lock Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11namei: make may_follow_link() safe in RCU modeAl Viro
We *can't* call that audit garbage in RCU mode - it's doing a weird mix of allocations (GFP_NOFS, immediately followed by GFP_KERNEL) and I'm not touching that... thing again. So if this security sclero^Whardening feature gets triggered when we are in RCU mode, tough - we'll fail with -ECHILD and have everything restarted in non-RCU mode. Only to hit the same test and fail, this time with EACCES and with (oh, rapture) an audit spew produced. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11namei: make put_link() RCU-safeAl Viro
very simple - just make path_put() conditional on !RCU. Note that right now it doesn't get called in RCU mode - we leave it before getting anything into stack. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11new helper: free_page_put_link()Al Viro
similar to kfree_put_link() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11switch ->put_link() from dentry to inodeAl Viro
only one instance looks at that argument at all; that sole exception wants inode rather than dentry. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11security: make inode_follow_link RCU-walk awareNeilBrown
inode_follow_link now takes an inode and rcu flag as well as the dentry. inode is used in preference to d_backing_inode(dentry), particularly in RCU-walk mode. selinux_inode_follow_link() gets dentry_has_perm() and inode_has_perm() open-coded into it so that it can call avc_has_perm_flags() in way that is safe if LOOKUP_RCU is set. Calling avc_has_perm_flags() with rcu_read_lock() held means that when avc_has_perm_noaudit calls avc_compute_av(), the attempt to rcu_read_unlock() before calling security_compute_av() will not actually drop the RCU read-lock. However as security_compute_av() is completely in a read_lock()ed region, it should be safe with the RCU read-lock held. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11security/selinux: pass 'flags' arg to avc_audit() and avc_has_perm_flags()NeilBrown
This allows MAY_NOT_BLOCK to be passed, in RCU-walk mode, through the new avc_has_perm_flags() to avc_audit() and thence the slow_avc_audit. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11namei: pick_link() callers already have inodeAl Viro
no need to refetch (and once we move unlazy out of there, recheck ->d_seq). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11VFS: Handle lower layer dentry/inode in pathwalkDavid Howells
Make use of d_backing_inode() in pathwalk to gain access to an inode or dentry that's on a lower layer. Signed-off-by: David Howells <dhowells@redhat.com>
2015-05-11namei: store inode in nd->stack[]Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11namei: don't mangle nd->seq in lookup_fast()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11namei: explicitly pass seq number to unlazy_walk() when dentry != NULLAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11link_path_walk: use explicit returns for failure exitsAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11namei: lift terminate_walk() all the way upAl Viro
Lift it from link_path_walk(), trailing_symlink(), lookup_last(), mountpoint_last(), complete_walk() and do_last(). A _lot_ of those suckers merge. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11namei: lift link_path_walk() call out of trailing_symlink()Al Viro
Make trailing_symlink() return the pathname to traverse or ERR_PTR(-E...). A subtle point is that for "magic" symlinks it returns "" now - that leads to link_path_walk("", nd), which is immediately returning 0 and we are back to the treatment of the last component, at whereever the damn thing has left us. Reduces the stack footprint - link_path_walk() called on more shallow stack now. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11namei: path_init() calling conventions changeAl Viro
* lift link_path_walk() into callers; moving it down into path_init() had been a mistake. Stack footprint, among other things... * do _not_ call path_cleanup() after path_init() failure; on all failure exits out of it we have nothing for path_cleanup() to do * have path_init() return pathname or ERR_PTR(-E...) Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11namei: get rid of nameidata->baseAl Viro
we can do fdput() under rcu_read_lock() just fine; all we need to take care of is fetching nd->inode value first. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-10namei: split off filename_lookupat() with LOOKUP_PARENTAl Viro
new functions: filename_parentat() and path_parentat() resp. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-10namei: may_follow_link() - lift terminate_walk() on failures into callerAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-10namei: take increment of nd->depth into pick_link()Al Viro
Makes the situation much more regular - we avoid a strange state when the element just after the top of stack is used to store struct path of symlink, but isn't counted in nd->depth. This is much more regular, so the normal failure exits, etc., work fine. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-10namei: kill nd->linkAl Viro
Just store it in nd->stack[nd->depth].link right in pick_link(). Now that we make sure of stack expansion in pick_link(), we can do so... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-10may_follow_link(): trim argumentsAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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