... and don't skip on sanity checks. It's *not* a hot path, TYVM
(a couple of calls per a.out execve(), for pity sake) and headers of
random a.out binary are not to be trusted.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
... we are doing them on adjacent parts of file, so what happens is that
each subsequent call works to rebuild the iov_iter to exact state it
had been abandoned in by previous one. Just keep it through the entire
cifs_iovec_read(). And use copy_page_to_iter() instead of doing
kmap/copy_to_user/kunmap manually...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
I've switched the sanity checks on iovec to rw_copy_check_uvector();
we might need to do a local analog, if any behaviour differences are
not actually bugfixes here...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
... by that point the request we'd just resent is in the
head of the list anyway. Just return to the beginning of
the loop body...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Make delayed_free() call free_vfsmnt() so that we don't have two functions
doing the same job. This requires the calls to mnt_free_id() in free_vfsmnt()
to be moved into the callers of that function.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
the only thing it's doing these days is calculation of
upper limit for fs.nr_open sysctl and that can be done
statically
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
new flag in ->f_mode - FMODE_WRITER. Set by do_dentry_open() in case
when it has grabbed write access, checked by __fput() to decide whether
it wants to drop the sucker. Allows to stop bothering with mnt_clone_write()
in alloc_file(), along with fewer special_file() checks.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
it's pointless and actually leads to wrong behaviour in at least one
moderately convoluted case (pipe(), close one end, try to get to
another via /proc/*/fd and run into ETXTBUSY).
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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>
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>
If the dest_mnt is not shared, propagate_mnt() does nothing -
there's no mounts to propagate to and thus no copies to create.
Might as well don't bother calling it in that case.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* switch allocation to alloc_large_system_hash()
* make sizes overridable by boot parameters (mhash_entries=, mphash_entries=)
* switch mountpoint_hashtable from list_head to hlist_head
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Commit c74a3bdd9b ("ocfs2: add clustername to cluster connection") is
trying to strlcpy a string which was explicitly passed as NULL in the
very same patch, triggering a NULL ptr deref.
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: strlcpy (lib/string.c:388 lib/string.c:151)
CPU: 19 PID: 19426 Comm: trinity-c19 Tainted: G W 3.14.0-rc7-next-20140325-sasha-00014-g9476368-dirty #274
RIP: strlcpy (lib/string.c:388 lib/string.c:151)
Call Trace:
ocfs2_cluster_connect (fs/ocfs2/stackglue.c:350)
ocfs2_cluster_connect_agnostic (fs/ocfs2/stackglue.c:396)
user_dlm_register (fs/ocfs2/dlmfs/userdlm.c:679)
dlmfs_mkdir (fs/ocfs2/dlmfs/dlmfs.c:503)
vfs_mkdir (fs/namei.c:3467)
SyS_mkdirat (fs/namei.c:3488 fs/namei.c:3472)
tracesys (arch/x86/kernel/entry_64.S:749)
akpm: this patch probably disables the feature. A temporary thing to
avoid triviel oopses.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Goldwyn Rodrigues <rgoldwyn@suse.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently we allocated anon_inode_inode in anon_inodefs_mount. This is
somewhat fragile as if that function ever gets called again, it will
overwrite anon_inode_inode pointer. So move the initialization of
anon_inode_inode to anon_inode_init().
Signed-off-by: Jan Kara <jack@suse.cz>
[ Further simplified on suggestion from Dave Jones ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The previous commit removed the register_filesystem() call and the
associated error handling, but left the label for the error path that no
longer exists. Remove that too.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
anon_inodefs filesystem is a kernel internal filesystem userspace
shouldn't mess with. Remove registration of it so userspace cannot
even try to mount it (which would fail anyway because the filesystem is
MS_NOUSER).
This fixes an oops triggered by trinity when it tried mounting
anon_inodefs which overwrote anon_inode_inode pointer while other CPU
has been in anon_inode_getfile() between ihold() and d_instantiate().
Thus effectively creating dentry pointing to an inode without holding a
reference to it.
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull nfsd fix frm Bruce Fields:
"J R Okajima sent this early and I was just slow to pass it along,
apologies. Fortunately it's a simple fix"
* 'nfsd-next' of git://linux-nfs.org/~bfields/linux:
nfsd: fix lost nfserrno() call in nfsd_setattr()
We can get false negative from __lookup_mnt() if an unrelated vfsmount
gets moved. In that case legitimize_mnt() is guaranteed to fail,
and we will fall back to non-RCU walk... unless we end up running
into a hard error on a filesystem object we wouldn't have reached
if not for that false negative. IOW, delaying that check until
the end of pathname resolution is wrong - we should recheck right
after we attempt to cross the mountpoint. We don't need to recheck
unless we see d_mountpoint() being true - in that case even if
we have just raced with mount/umount, we can simply go on as if
we'd come at the moment when the sucker wasn't a mountpoint; if we
run into a hard error as the result, it was a legitimate outcome.
__lookup_mnt() returning NULL is different in that respect, since
it might've happened due to operation on completely unrelated
mountpoint.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
In all callchains leading to prepend_name(), the value left in *buflen
is eventually discarded unused if prepend_name() has returned a negative.
So we are free to do what prepend() does, and subtract from *buflen
*before* checking for underflow (which turns into checking the sign
of subtraction result, of course).
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Commit bd2a31d522 ("get rid of fget_light()") introduced the
__fdget_pos() function, which returns the resulting file pointer and
fdput flags combined in an 'unsigned long'. However, it also changed the
behavior to return files with FMODE_PATH set, which shouldn't happen
because read(), write(), lseek(), etc. aren't allowed on such files.
This commit restores the old behavior.
This regression actually had no effect on read() and write() since
FMODE_READ and FMODE_WRITE are not set on file descriptors opened with
O_PATH, but it did cause lseek() on a file descriptor opened with O_PATH
to fail with ESPIPE rather than EBADF.
Signed-off-by: Eric Biggers <ebiggers3@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Commit 9c225f2655 ("vfs: atomic f_pos accesses as per POSIX") changed
several system calls to use fdget_pos() instead of fdget(), but missed
sys_llseek(). Fix it.
Signed-off-by: Eric Biggers <ebiggers3@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull CIFS fixes from Steve French:
"A fix for the problem which Al spotted in cifs_writev and a followup
(noticed when fixing CVE-2014-0069) patch to ensure that cifs never
sends more than the smb frame length over the socket (as we saw with
that cifs_iovec_write problem that Jeff fixed last month)"
* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
cifs: mask off top byte in get_rfc1002_length()
cifs: sanity check length of data to send before sending
CIFS: Fix wrong pos argument of cifs_find_lock_conflict
