Since tmpfs has no persistent storage, it pins all its dentries in memory
so they have d_count=1 when other file systems would have d_count=0.
->lookup is only used to create new dentries. If the caller doesn't
instantiate it, it's freed immediately at dput(). ->readdir reads
directly from the dcache and depends on the dentries being hashed.

When an ecryptfs mount is mounted, it associates the lower file and dentry
with the ecryptfs files as they're accessed. When it's umounted and
destroys all the in-memory ecryptfs inodes, it fput's the lower_files and
d_drop's the lower_dentries. Commit 4981e081 added this and a d_delete in
2008 and several months later commit caeeeecf removed the d_delete. I
believe the d_drop() needs to be removed as well.

The d_drop effectively hides any file that has been accessed via ecryptfs
from the underlying tmpfs since it depends on it being hashed for it to
be accessible. I've removed the d_drop on my development node and see no
ill effects with basic testing on both tmpfs and persistent storage.

As a side effect, after ecryptfs d_drops the dentries on tmpfs, tmpfs
BUGs on umount. This is due to the dentries being unhashed.
tmpfs->kill_sb is kill_litter_super which calls d_genocide to drop
the reference pinning the dentry. It skips unhashed and negative dentries,
but shrink_dcache_for_umount_subtree doesn't. Since those dentries
still have an elevated d_count, we get a BUG().

This patch removes the d_drop call and fixes both issues.

This issue was reported at:
https://bugzilla.novell.com/show_bug.cgi?id=567887Reported-by: NÁrpád Bíró <biroa@demasz.hu>
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Cc: Dustin Kirkland <kirkland@canonical.com>
Cc: stable@kernel.org
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

In ecryptfs_destroy_inode(), inode_info->lower_file_mutex is locked,
and just after the mutex is unlocked, the code does:

 	kmem_cache_free(ecryptfs_inode_info_cache, inode_info);

This means that if another context could possibly try to take the same
mutex as ecryptfs_destroy_inode(), then it could end up getting the
mutex just before the data structure containing the mutex is freed.
So any such use would be an obvious use-after-free bug (catchable with
slab poisoning or mutex debugging), and therefore the locking in
ecryptfs_destroy_inode() is not needed and can be dropped.

Similarly, in ecryptfs_destroy_crypt_stat(), crypt_stat->keysig_list_mutex
is locked, and then the mutex is unlocked just before the code does:

 	memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));

Therefore taking this mutex is similarly not necessary.

Removing this locking fixes false-positive lockdep reports such as the
following (and they are false-positives for exactly the same reason
that the locking is not needed):

=================================
[ INFO: inconsistent lock state ]
2.6.31-2-generic #14~rbd3
---------------------------------
inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.
kswapd0/323 [HC0[0]:SC0[0]:HE1:SE1] takes:
 (&inode_info->lower_file_mutex){+.+.?.}, at: [<ffffffff81210d34>] ecryptfs_destroy_inode+0x34/0x100
{RECLAIM_FS-ON-W} state was registered at:
  [<ffffffff8108c02c>] mark_held_locks+0x6c/0xa0
  [<ffffffff8108c10f>] lockdep_trace_alloc+0xaf/0xe0
  [<ffffffff81125a51>] kmem_cache_alloc+0x41/0x1a0
  [<ffffffff8113117a>] get_empty_filp+0x7a/0x1a0
  [<ffffffff8112dd46>] dentry_open+0x36/0xc0
  [<ffffffff8121a36c>] ecryptfs_privileged_open+0x5c/0x2e0
  [<ffffffff81210283>] ecryptfs_init_persistent_file+0xa3/0xe0
  [<ffffffff8120e838>] ecryptfs_lookup_and_interpose_lower+0x278/0x380
  [<ffffffff8120f97a>] ecryptfs_lookup+0x12a/0x250
  [<ffffffff8113930a>] real_lookup+0xea/0x160
  [<ffffffff8113afc8>] do_lookup+0xb8/0xf0
  [<ffffffff8113b518>] __link_path_walk+0x518/0x870
  [<ffffffff8113bd9c>] path_walk+0x5c/0xc0
  [<ffffffff8113be5b>] do_path_lookup+0x5b/0xa0
  [<ffffffff8113bfe7>] user_path_at+0x57/0xa0
  [<ffffffff811340dc>] vfs_fstatat+0x3c/0x80
  [<ffffffff8113424b>] vfs_stat+0x1b/0x20
  [<ffffffff81134274>] sys_newstat+0x24/0x50
  [<ffffffff81013132>] system_call_fastpath+0x16/0x1b
  [<ffffffffffffffff>] 0xffffffffffffffff
irq event stamp: 7811
hardirqs last  enabled at (7811): [<ffffffff810c037f>] call_rcu+0x5f/0x90
hardirqs last disabled at (7810): [<ffffffff810c0353>] call_rcu+0x33/0x90
softirqs last  enabled at (3764): [<ffffffff810631da>] __do_softirq+0x14a/0x220
softirqs last disabled at (3751): [<ffffffff8101440c>] call_softirq+0x1c/0x30

other info that might help us debug this:
2 locks held by kswapd0/323:
 #0:  (shrinker_rwsem){++++..}, at: [<ffffffff810f67ed>] shrink_slab+0x3d/0x190
 #1:  (&type->s_umount_key#35){.+.+..}, at: [<ffffffff811429a1>] prune_dcache+0xd1/0x1b0

stack backtrace:
Pid: 323, comm: kswapd0 Tainted: G         C 2.6.31-2-generic #14~rbd3
Call Trace:
 [<ffffffff8108ad6c>] print_usage_bug+0x18c/0x1a0
 [<ffffffff8108aff0>] ? check_usage_forwards+0x0/0xc0
 [<ffffffff8108bac2>] mark_lock_irq+0xf2/0x280
 [<ffffffff8108bd87>] mark_lock+0x137/0x1d0
 [<ffffffff81164710>] ? fsnotify_clear_marks_by_inode+0x30/0xf0
 [<ffffffff8108bee6>] mark_irqflags+0xc6/0x1a0
 [<ffffffff8108d337>] __lock_acquire+0x287/0x430
 [<ffffffff8108d585>] lock_acquire+0xa5/0x150
 [<ffffffff81210d34>] ? ecryptfs_destroy_inode+0x34/0x100
 [<ffffffff8108d2e7>] ? __lock_acquire+0x237/0x430
 [<ffffffff815526ad>] __mutex_lock_common+0x4d/0x3d0
 [<ffffffff81210d34>] ? ecryptfs_destroy_inode+0x34/0x100
 [<ffffffff81164710>] ? fsnotify_clear_marks_by_inode+0x30/0xf0
 [<ffffffff81210d34>] ? ecryptfs_destroy_inode+0x34/0x100
 [<ffffffff8129a91e>] ? _raw_spin_unlock+0x5e/0xb0
 [<ffffffff81552b36>] mutex_lock_nested+0x46/0x60
 [<ffffffff81210d34>] ecryptfs_destroy_inode+0x34/0x100
 [<ffffffff81145d27>] destroy_inode+0x87/0xd0
 [<ffffffff81146b4c>] generic_delete_inode+0x12c/0x1a0
 [<ffffffff81145832>] iput+0x62/0x70
 [<ffffffff811423c8>] dentry_iput+0x98/0x110
 [<ffffffff81142550>] d_kill+0x50/0x80
 [<ffffffff81142623>] prune_one_dentry+0xa3/0xc0
 [<ffffffff811428b1>] __shrink_dcache_sb+0x271/0x290
 [<ffffffff811429d9>] prune_dcache+0x109/0x1b0
 [<ffffffff81142abf>] shrink_dcache_memory+0x3f/0x50
 [<ffffffff810f68dd>] shrink_slab+0x12d/0x190
 [<ffffffff810f9377>] balance_pgdat+0x4d7/0x640
 [<ffffffff8104c4c0>] ? finish_task_switch+0x40/0x150
 [<ffffffff810f63c0>] ? isolate_pages_global+0x0/0x60
 [<ffffffff810f95f7>] kswapd+0x117/0x170
 [<ffffffff810777a0>] ? autoremove_wake_function+0x0/0x40
 [<ffffffff810f94e0>] ? kswapd+0x0/0x170
 [<ffffffff810773be>] kthread+0x9e/0xb0
 [<ffffffff8101430a>] child_rip+0xa/0x20
 [<ffffffff81013c90>] ? restore_args+0x0/0x30
 [<ffffffff81077320>] ? kthread+0x0/0xb0
 [<ffffffff81014300>] ? child_rip+0x0/0x20
Signed-off-by: NRoland Dreier <roland@digitalvampire.org>
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

Move BKL into ->put_super from the only caller.  A couple of
filesystems had trivial enough ->put_super (only kfree and NULLing of
s_fs_info + stuff in there) to not get any locking: coda, cramfs, efs,
hugetlbfs, omfs, qnx4, shmem, all others got the full treatment.  Most
of them probably don't need it, but I'd rather sort that out individually.
Preferably after all the other BKL pushdowns in that area.

[AV: original used to move lock_super() down as well; these changes are
removed since we don't do lock_super() at all in generic_shutdown_super()
now]
[AV: fuse, btrfs and xfs are known to need no damn BKL, exempt]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

A feature was added to the eCryptfs umount helper to automatically
unlink the keys used for an eCryptfs mount from the kernel keyring upon
umount.  This patch keeps the unrecognized mount option warnings for
ecryptfs_unlink_sigs out of the logs.
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

The filename encryption key signature is not properly displayed in
/proc/mounts.  The "ecryptfs_sig=" mount option name is displayed for
all global authentication tokens, included those for filename keys.

This patch checks the global authentication token flags to determine if
the key is a FEKEK or FNEK and prints the appropriate mount option name
before the signature.
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

ecryptfs_debug really should not be a mount option; it is not per-mount,
but rather sets a global "ecryptfs_verbosity" variable which affects all
mounted filesysytems.  It's already settable as a module load option,
I think we can leave it at that.

Also, if set, since secret values come out in debug messages, kick
things off with a stern warning.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Acked-by: NMike Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Change ecryptfs_show_options to reflect the actual mount options in use.
Note that this does away with the "dir=" output, which is not a valid mount
option and appears to be unused.

Mount options such as "ecryptfs_verbose" and "ecryptfs_xattr_metadata" are
somewhat indeterminate for a given fs, but in any case the reported mount
options can be used in a new mount command to get the same behavior.

[akpm@linux-foundation.org: fix printk warning]
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Acked-by: NMichael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch corrects some erroneous dentry handling in eCryptfs.

If there is a problem creating the lower file, then there is nothing that
the persistent lower file can do to really help us.  This patch makes a
vfs_create() failure in the lower filesystem always lead to an
unconditional do_create failure in eCryptfs.

Under certain sequences of operations, the eCryptfs dentry can remain in
the dcache after an unlink.  This patch calls d_drop() on the eCryptfs
dentry to correct this.

eCryptfs has no business calling d_delete() directly on a lower
filesystem's dentry.  This patch removes the call to d_delete() on the
lower persistent file's dentry in ecryptfs_destroy_inode().

(Thanks to David Kleikamp, Eric Sandeen, and Jeff Moyer for helping
identify and resolve this issue)
Signed-off-by: NMichael Halcrow <mhalcrow@us.ibm.com>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Eric Sandeen <sandeen@redhat.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Initialize persistent lower file on inode create.
Signed-off-by: NMichael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch sets up and destroys the persistent lower file for each eCryptfs
inode.
Signed-off-by: NMichael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Andrew Morton wrote:
> > +int ecryptfs_destruct_crypto(void)
>
> ecryptfs_destroy_crypto would be more grammatically correct ;)

Grammatical fix for some function names.
Signed-off-by: NMichael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch is inspired by Arjan's "Patch series to mark struct
file_operations and struct inode_operations const".

Compile tested with gcc & sparse.
Signed-off-by: NJosef 'Jeff' Sipek <jsipek@cs.sunysb.edu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

SLAB_KERNEL is an alias of GFP_KERNEL.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

There is no point to calling the lower umount_begin when the eCryptfs
umount_begin is called.
Signed-off-by: NMichael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

eCryptfs is a stacked cryptographic filesystem for Linux.  It is derived from
Erez Zadok's Cryptfs, implemented through the FiST framework for generating
stacked filesystems.  eCryptfs extends Cryptfs to provide advanced key
management and policy features.  eCryptfs stores cryptographic metadata in the
header of each file written, so that encrypted files can be copied between
hosts; the file will be decryptable with the proper key, and there is no need
to keep track of any additional information aside from what is already in the
encrypted file itself.

[akpm@osdl.org: updates for ongoing API changes]
[bunk@stusta.de: cleanups]
[akpm@osdl.org: alpha build fix]
[akpm@osdl.org: cleanups]
[tytso@mit.edu: inode-diet updates]
[pbadari@us.ibm.com: generic_file_*_read/write() interface updates]
[rdunlap@xenotime.net: printk format fixes]
[akpm@osdl.org: make slab creation and teardown table-driven]
Signed-off-by: NPhillip Hellewell <phillip@hellewell.homeip.net>
Signed-off-by: NMichael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: NErez Zadok <ezk@cs.sunysb.edu>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NStephan Mueller <smueller@chronox.de>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NBadari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: NRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>