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- 17 May, 2016 1 commit
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Maxim Patlasov authored
[ Upstream commit 7ae8fd03 ] propagate_one(m) calculates "type" argument for copy_tree() like this: > if (m->mnt_group_id == last_dest->mnt_group_id) { > type = CL_MAKE_SHARED; > } else { > type = CL_SLAVE; > if (IS_MNT_SHARED(m)) > type |= CL_MAKE_SHARED; > } The "type" argument then governs clone_mnt() behavior with respect to flags and mnt_master of new mount. When we iterate through a slave group, it is possible that both current "m" and "last_dest" are not shared (although, both are slaves, i.e. have non-NULL mnt_master-s). Then the comparison above erroneously makes new mount shared and sets its mnt_master to last_source->mnt_master. The patch fixes the problem by handling zero mnt_group_id-s as though they are unequal. The similar problem exists in the implementation of "else" clause above when we have to ascend upward in the master/slave tree by calling: > last_source = last_source->mnt_master; > last_dest = last_source->mnt_parent; proper number of times. The last step is governed by "n->mnt_group_id != last_dest->mnt_group_id" condition that may lie if both are zero. The patch fixes this case in the same way as the former one. [AV: don't open-code an obvious helper...] Signed-off-by:
Maxim Patlasov <mpatlasov@virtuozzo.com> Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
Sasha Levin <sasha.levin@oracle.com>
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- 30 Aug, 2014 1 commit
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Al Viro authored
The check in __propagate_umount() ("has somebody explicitly mounted something on that slave?") is done *before* taking the already doomed victims out of the child lists. Cc: stable@vger.kernel.org Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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- 02 Apr, 2014 1 commit
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Al Viro authored
The current mainline has copies propagated to *all* nodes, then tears down the copies we made for nodes that do not contain counterparts of the desired mountpoint. That sets the right propagation graph for the copies (at teardown time we move the slaves of removed node to a surviving peer or directly to master), but we end up paying a fairly steep price in useless allocations. It's fairly easy to create a situation where N calls of mount(2) create exactly N bindings, with O(N^2) vfsmounts allocated and freed in process. Fortunately, it is possible to avoid those allocations/freeings. The trick is to create copies in the right order and find which one would've eventually become a master with the current algorithm. It turns out to be possible in O(nodes getting propagation) time and with no extra allocations at all. One part is that we need to make sure that eventual master will be created before its slaves, so we need to walk the propagation tree in a different order - by peer groups. And iterate through the peers before dealing with the next group. Another thing is finding the (earlier) copy that will be a master of one we are about to create; to do that we are (temporary) marking the masters of mountpoints we are attaching the copies to. Either we are in a peer of the last mountpoint we'd dealt with, or we have the following situation: we are attaching to mountpoint M, the last copy S_0 had been attached to M_0 and there are sequences S_0...S_n, M_0...M_n such that S_{i+1} is a master of S_{i}, S_{i} mounted on M{i} and we need to create a slave of the first S_{k} such that M is getting propagation from M_{k}. It means that the master of M_{k} will be among the sequence of masters of M. On the other hand, the nearest marked node in that sequence will either be the master of M_{k} or the master of M_{k-1} (the latter - in the case if M_{k-1} is a slave of something M gets propagation from, but in a wrong peer group). So we go through the sequence of masters of M until we find a marked one (P). Let N be the one before it. Then we go through the sequence of masters of S_0 until we find one (say, S) mounted on a node D that has P as master and check if D is a peer of N. If it is, S will be the master of new copy, if not - the master of S will be. That's it for the hard part; the rest is fairly simple. Iterator is in next_group(), handling of one prospective mountpoint is propagate_one(). It seems to survive all tests and gives a noticably better performance than the current mainline for setups that are seriously using shared subtrees. Cc: stable@vger.kernel.org Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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- 30 Mar, 2014 1 commit
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Al Viro authored
fixes RCU bug - walking through hlist is safe in face of element moves, since it's self-terminating. Cyclic lists are not - if we end up jumping to another hash chain, we'll loop infinitely without ever hitting the original list head. [fix for dumb braino folded] Spotted by: Max Kellermann <mk@cm4all.com> Cc: stable@vger.kernel.org Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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- 25 Oct, 2013 3 commits
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Al Viro authored
Instead of passing the direction as argument (and checking it on every step through the hash chain), just have separate __lookup_mnt() and __lookup_mnt_last(). And use the standard iterators... Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
aka br_write_{lock,unlock} of vfsmount_lock. Inlines in fs/mount.h, vfsmount_lock extern moved over there as well. Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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- 31 May, 2013 1 commit
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Takashi Iwai authored
When the group id of a shared mount is not allocated, the umount still tries to call mnt_release_group_id(), which eventually hits a kernel warning at ida_remove() spewing a message like: ida_remove called for id=0 which is not allocated. This patch fixes the bug simply checking the group id in the caller. Reported-by:
Cristian Rodríguez <crrodriguez@opensuse.org> Signed-off-by:
Takashi Iwai <tiwai@suse.de> Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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- 09 Apr, 2013 2 commits
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Al Viro authored
which allows to kill the last argument of umount_tree() and make release_mounts() static. Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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- 27 Mar, 2013 1 commit
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Eric W. Biederman authored
As a matter of policy MNT_READONLY should not be changable if the original mounter had more privileges than creator of the mount namespace. Add the flag CL_UNPRIVILEGED to note when we are copying a mount from a mount namespace that requires more privileges to a mount namespace that requires fewer privileges. When the CL_UNPRIVILEGED flag is set cause clone_mnt to set MNT_NO_REMOUNT if any of the mnt flags that should never be changed are set. This protects both mount propagation and the initial creation of a less privileged mount namespace. 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>
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- 14 Jul, 2012 1 commit
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David Howells authored
copy_tree() can theoretically fail in a case other than ENOMEM, but always returns NULL which is interpreted by callers as -ENOMEM. Change it to return an explicit error. Also change clone_mnt() for consistency and because union mounts will add new error cases. Thanks to Andreas Gruenbacher <agruen@suse.de> for a bug fix. [AV: folded braino fix by Dan Carpenter] Original-author: Valerie Aurora <vaurora@redhat.com> Signed-off-by:
David Howells <dhowells@redhat.com> Cc: Valerie Aurora <valerie.aurora@gmail.com> Cc: Andreas Gruenbacher <agruen@suse.de> Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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- 30 May, 2012 1 commit
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Andi Kleen authored
lglocks and brlocks are currently generated with some complicated macros in lglock.h. But there's no reason to not just use common utility functions and put all the data into a common data structure. In preparation, this patch changes the API to look more like normal function calls with pointers, not magic macros. The patch is rather large because I move over all users in one go to keep it bisectable. This impacts the VFS somewhat in terms of lines changed. But no actual behaviour change. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by:
Andi Kleen <ak@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Rusty Russell <rusty@rustcorp.com.au> Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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- 04 Jan, 2012 27 commits
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
make IS_MNT_SLAVE take struct mount * at the same time Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
next pile of horrors, similar to mnt_parent one; this time it's mnt_master. Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
the second victim... Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
taken out of struct vfsmount into struct mount Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
switch __lookup_mnt() to returning struct mount *; callers adjusted. Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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