This is the second fix of the following symptom:

UBIFS error (pid 34456): could not find an empty LEB

which sometimes happens after power cuts when we mount the file-system - UBIFS
refuses it with the above error message which comes from the
'ubifs_rcvry_gc_commit()' function. I can reproduce this using the integck test
with the UBIFS power cut emulation enabled.

Analysis of the problem.

Currently UBIFS replay seeks the journal heads to the last _replayed_ bud.
But the buds are replayed out-of-order, so the replay basically seeks journal
heads to the "random" bud belonging to this head, and not to the _last_ one.

The result of this is that the GC head may be seeked to a full LEB with no free
space, or very little free space. And 'ubifs_rcvry_gc_commit()' tries to find a
fully or mostly dirty LEB to match the current GC head (because we need to
garbage-collect that dirty LEB at one go, because we do not have @c->gc_lnum).
So 'ubifs_find_dirty_leb()' fails and we fall back to finding an empty LEB and
also fail. As a result - recovery fails and mounting fails.

This patch teaches the replay to initialize the GC heads exactly to the latest
buds, i.e. the buds which have the largest sequence number in corresponding
log reference nodes.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Cc: stable@kernel.org

Currently UBIFS has a small optimization - it frees write-buffers when it is
re-mounted from R/W mode to R/O mode. Of course, when it is mounted R/O, it
does not allocate write-buffers as well.

This optimization is nice but it leads to subtle problems and complications
in recovery, which I can reproduce using the integck test. The symptoms are
that after a power cut the file-system cannot be mounted if we first mount
it R/O, and then re-mount R/W - 'ubifs_rcvry_gc_commit()' prints:

UBIFS error (pid 34456): could not find an empty LEB

Analysis of the  problem.

When mounting R/W, the reply process sets journal heads to buds [1], but
when mounting R/O - it does not do this, because the write-buffers are not
allocated. So 'ubifs_rcvry_gc_commit()' works completely differently for the
same file-system but for the following 2 cases:

1. mounting R/W after a power cut and recover
2. mounting R/O after a power cut, re-mounting R/W and run deferred recovery

In the former case, we have journal heads seeked to the a bud, in the latter
case, they are non-seeked (wbuf->lnum == -1). So in the latter case we do not
try to recover the GC LEB by garbage-collecting to the GC head, but we just
try to find an empty LEB, and there may be no empty LEBs, so we just fail.
On the other hand, in the former case (mount R/W), we are able to make a GC LEB
(@c->gc_lnum) by garbage-collecting.

Thus, let's remove this small nice optimization and always allocate
write-buffers. This should not make too big difference - we have only 3
of them, each of max. write unit size, which is usually 2KiB. So this is
about 6KiB of RAM for the typical case, and only when mounted R/O.

[1]: Note, currently the replay process is setting (seeking) the journal heads
to _some_ buds, not necessarily to the buds which had been the journal heads
before the power cut happened. This will be fixed separately.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Cc: stable@kernel.org

This patch fixes the following symptoms:
1. Unmount UBIFS cleanly.
2. Start mounting UBIFS R/W and have a power cut immediately
3. Start mounting UBIFS R/O, this succeeds
4. Try to re-mount UBIFS R/W - this fails immediately or later on,
   because UBIFS will write the master node to the flash area
   which has been written before.

The analysis of the problem:

1. UBIFS is unmounted cleanly, both copies of the master node are clean.
2. UBIFS is being mounter R/W, starts changing master node copy 1, and
   a power cut happens. The copy N1 becomes corrupted.
3. UBIFS is being mounted R/O. It notices the copy N1 is corrupted and
   reads copy N2. Copy N2 is clean.
4. Because of R/O mode, UBIFS cannot recover copy 1.
5. The mount code (ubifs_mount()) sees that the master node is clean,
   so it decides that no recovery is needed.
6. We are re-mounting R/W. UBIFS believes no recovery is needed and
   starts updating the master node, but copy N1 is still corrupted
   and was not recovered!

Fix this problem by marking the master node as dirty every time we
recover it and we are in R/O mode. This forces further recovery and
the UBIFS cleans-up the corruptions and recovers the copy N1 when
re-mounting R/W later.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Cc: stable@kernel.org

When UBIFS switches to R/O mode because it detects I/O failures, then
when we unmount, we still may have allocated budget, and the assertions
which verify that we have not budget will fire. But it is expected to
have the budget in case of I/O failures, so the assertion warnings will
be false. Suppress them for the I/O failure case.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

This patch fixes UBIFS mount failure when the debugging support is enabled,
we are recovering from a power cut, we were first mounter R/O and we are
re-mounting R/W. In this case we should not assume that the amount of free
space before we have re-mounted R/W and after are equivalent, because
when we have mounted R/O the file-system is in a non-committed state so
the amount of free space is slightly smaller, due to the fact that we cannot
predict the amount of free space precisely before we commit.

This patch fixes the issue by skipping the debugging check in case of
recovery. This issue was reported by Caizhiyong <caizhiyong@huawei.com>
here: http://thread.gmane.org/gmane.linux.drivers.mtd/34350/focus=34387Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Reported-by: NCaizhiyong <caizhiyong@huawei.com>
Cc: stable@kernel.org [2.6.30+]

When compiling UBIFS with CONFIG_UBIFS_FS_DEBUG not set,
gcc-4.5.2 generates a slew of "warning: statement with no effect"
on references to non-void functions defined as 0.
To avoid these warnings, replace #defines with dummy inline functions.

Artem: massage the patch a bit, also remove the duplicate
       'dbg_check_lprops()' prototype.
Signed-off-by: NMaksim Rayskiy <maksim.rayskiy@gmail.com>
Acked-by: NMike Frysinger <vapier@gentoo.org>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

This patch fixes severe UBIFS bug: UBIFS oopses when we 'fsync()' an
file on R/O-mounter file-system. We (the UBIFS authors) incorrectly
thought that VFS would not propagate 'fsync()' down to the file-system
if it is read-only, but this is not the case.

It is easy to exploit this bug using the following simple perl script:

use strict;
use File::Sync qw(fsync sync);

die "File path is not specified" if not defined $ARGV[0];
my $path = $ARGV[0];

open FILE, "<", "$path" or die "Cannot open $path: $!";
fsync(\*FILE) or die "cannot fsync $path: $!";
close FILE or die "Cannot close $path: $!";

Thanks to Reuben Dowle <Reuben.Dowle@navico.com> for reporting about this
issue.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Reported-by: NReuben Dowle <Reuben.Dowle@navico.com>
Cc: stable@kernel.org

With the ->sync_page() hook gone, we have a few users that
add their own static address_space_operations without any
functions defined.

fs/inode.c already has an empty_aops that it uses for init
purposes. Lets export that and use it in the places where
an otherwise empty aops was defined.
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

This patch fixes a debugging failure with which looks like this:
UBIFS error (pid 32313): dbg_check_space_info: free space changed from 6019344 to 6022654

The reason for this failure is described in the comment this patch adds
to the code. But in short - 'c->freeable_cnt' may be different before
and after re-mounting, and this is normal. So the debugging code should
make sure that free space calculations do not depend on 'c->freeable_cnt'.

A similar issue has been reported here:
http://lists.infradead.org/pipermail/linux-mtd/2011-April/034647.html

This patch should fix it.

For the -stable guys: this patch is only relevant for kernels 2.6.30
onwards.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Cc: stable@kernel.org [2.6.30+]

The debug interface is substandard and on error returns either
NULL or an error code packed in the pointer. So using "IS_ERR"
for the pointers returned by debugfs function is incorrect.
Instead, we should use IS_ERR_OR_NULL.

This path is an improved vestion of the original patch from
Phil Carmody.
Reported-by: NPhil Carmody <ext-phil.2.carmody@nokia.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Acked-by: NPhil Carmody <ext-phil.2.carmody@nokia.com>

This is just a small clean-up patch which simlifies and unifies the
error path in the dbg_debugfs_init_fs(). We have common error path
for all failure cases in this function except of the very first
case. And this patch makes the first failure case use the same
error path as the other cases by using the 'fname' and 'dent'
variables.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Acked-by: NPhil Carmody <ext-phil.2.carmody@nokia.com>

All UBIFS needs is to make sure we stacktraces when UBIFS debugging
is enabled. It is enough to select KALLSYMS for this, KALLSYMS_ALL
is not necessary. Moreover, Randy Dunlap reported that UBIFS causes
the following Kconfig dependency warning:

warning: (UBIFS_FS_DEBUG && LOCKDEP && LATENCYTOP) selects KALLSYMS_ALL
which has unmet direct dependencies (DEBUG_KERNEL && KALLSYMS)

The reason is that KALLSYMS_ALL requires DEBUG_KERNEL and KALLSYMS, so
ideally, to select KALLSYMS_ALL we'd need to select DEBUG_KERNEL and
KALLSYMS first.

This seems to be too much to select. The easiest way to go is to forget
about KALLSYMS_ALL and just select KALLSYMS when UBIFS debugging is
enabled - that should be enough for stackdumps.
Reported-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Acked-by: NRandy Dunlap <randy.dunlap@oracle.com>

This patch fixes UBIFS assertion warnings like:

UBIFS assert failed in ubifs_leb_unmap at 135 (pid 29365)
Pid: 29365, comm: integck Tainted: G          I 2.6.37-ubi-2.6+ #34
Call Trace:
 [<ffffffffa047c663>] ubifs_lpt_init+0x95e/0x9ee [ubifs]
 [<ffffffffa04623a7>] ubifs_remount_fs+0x2c7/0x762 [ubifs]
 [<ffffffff810f066e>] do_remount_sb+0xb6/0x101
 [<ffffffff81106ff4>] ? do_mount+0x191/0x78e
 [<ffffffff811070bb>] do_mount+0x258/0x78e
 [<ffffffff810da1e8>] ? alloc_pages_current+0xa2/0xc5
 [<ffffffff81107674>] sys_mount+0x83/0xbd
 [<ffffffff81009a12>] system_call_fastpath+0x16/0x1b

They happen when we re-mount from R/O mode to R/W mode. While
re-mounting, we write to the media, but we still have the c->ro_mount
flag set. The fix is very simple - just clear the flag before
starting re-mounting R/W.

These warnings are caused by the following commit:
2ef13294

For -stable guys: this bug was introduced in 2.6.38, this is materieal
for 2.6.38-stable.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Cc: stable@kernel.org [2.6.38]

Thanks to coverity which spotted that UBIFS will oops if 'kmalloc()'
in 'read_pnode()' fails and we dereference a NULL 'pnode' pointer
when we 'goto out'.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Cc: stable@kernel.org

This fix makes the 'dbg_check_old_index()' function return
immediately if debugging is disabled, instead of executing
incorrect 'goto out' which causes UBIFS to:

1. Allocate memory
2. Read the flash

On every commit. OK, we do not commit that often, but it is
still silly to do unneeded I/O anyway.

Credits to coverity for spotting this silly issue.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Cc: stable@kernel.org

Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>

This patch fixes the following UBIFS assertion warning:

UBIFS assert failed in do_readpage at 115 (pid 199)
[<b00321b8>] (unwind_backtrace+0x0/0xdc) from [<af025118>]
(do_readpage+0x108/0x594 [ubifs])
[<af025118>] (do_readpage+0x108/0x594 [ubifs]) from [<af025764>]
(ubifs_write_end+0x1c0/0x2e8 [ubifs])
[<af025764>] (ubifs_write_end+0x1c0/0x2e8 [ubifs]) from
[<b00a0164>] (generic_file_buffered_write+0x18c/0x270)
[<b00a0164>] (generic_file_buffered_write+0x18c/0x270) from
[<b00a08d4>] (__generic_file_aio_write+0x478/0x4c0)
[<b00a08d4>] (__generic_file_aio_write+0x478/0x4c0) from
[<b00a0984>] (generic_file_aio_write+0x68/0xc8)
[<b00a0984>] (generic_file_aio_write+0x68/0xc8) from
[<af024a78>] (ubifs_aio_write+0x178/0x1d8 [ubifs])
[<af024a78>] (ubifs_aio_write+0x178/0x1d8 [ubifs]) from
[<b00d104c>] (do_sync_write+0xb0/0x100)
[<b00d104c>] (do_sync_write+0xb0/0x100) from [<b00d1abc>]
(vfs_write+0xac/0x154)
[<b00d1abc>] (vfs_write+0xac/0x154) from [<b00d1c10>]
(sys_write+0x3c/0x68)
[<b00d1c10>] (sys_write+0x3c/0x68) from [<b002d9a0>]
(ret_fast_syscall+0x0/0x2c)

The 'PG_checked' flag is used to indicate that the page does not
supposedly exist on the media (e.g., a hole or a page beyond the
inode size), so it requires slightly bigger budget, because we have
to account the indexing size increase. And this flag basically
tells that the budget for this page has to be "new page budget".
The "new page budget" is slightly bigger than the "existing page
budget".

The 'do_readpage()' function has the following assertion which
sometimes is hit: 'ubifs_assert(!PageChecked(page))'. Obviously,
the meaning of this assertion is: "I should not be asked to read
a page which does not exist on the media".

However, in 'ubifs_write_begin()' we have a small "trick". Notice,
that VFS may write pages which were not read yet, so the page data
were not loaded from the media to the page cache yet. If VFS tells
that it is going to change only some part of the page, we obviously
have to load it from the media. However, if VFS tells that it is
going to change whole page, we do not read it from the media for
optimization purposes.

However, since we do not read it, we do not know if it exists on
the media or not (a hole, etc). So we set the 'PG_checked' flag
to this page to force bigger budget, just in case.

So 'ubifs_write_begin()' sets 'PG_checked'. Then we are in
'ubifs_write_end()'. And VFS tells us: "hey, for some reasons I
changed my mind and did not change whole page". Frankly, I do not
know why this happens, but I hit this somehow on an ARM platform.
And this is extremely rare.

So in this case UBIFS does the following:

1. Cancels allocated budget.
2. Loads the page from the media by calling 'do_readpage()'.
3. Asks VFS to repeat the whole write operation from the very
   beginning (call '->write_begin() again, etc).

And the assertion warning is hit at the step 2 - remember we have
the 'PG_checked' set for this page, and 'do_readpage()' does not
like this. So this patch fixes the problem by adding step 1.5 and
cleaning the 'PG_checked' before calling 'do_readpage()'.

All in all, this patch does not fix any functionality issue, but it
silences UBIFS false positive warning which may happen in very very
rare cases.

And while on it, this patch also improves a commentary which explains
the reasons of setting the 'PG_checked' flag for the page. The old
commentary was a bit difficult to understand.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Simplify UBIFS configuration menu and kill the option to enable self-check
compile-time. We do not really need this because we can do this run-time
using the module parameters or the corresponding sysfs interfaces. And
there is a value in simplifying the kernel configuration menu which becomes
increasingly large.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

This patch fixes a brown-paperbag bug which was introduced by me:
I used incorrect "GFP_KERNEL | GFP_NOFS" allocation flags to make
sure my allocations do not cause write-back. But the correct form
is "GFP_NOFS".
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

And give it a kernel-doc comment.

[akpm@linux-foundation.org: btrfs changed in linux-next]
Signed-off-by: NSerge E. Hallyn <serge.hallyn@canonical.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Daniel Lezcano <daniel.lezcano@free.fr>
Acked-by: NDavid Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Clean-up commentaries in debug.h and remove references to non-existing
symblols.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

When debugging is enabled, we allocate a buffer of PEB size for
various debugging purposes. However, now all users of this buffer
are gone and we can safely remove it and save 128KiB or more RAM.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Instead of using pre-allocated 'c->dbg->buf' buffer in
'dbg_scan_orphans()', dynamically allocate it when needed. The intend
is to get rid of the pre-allocated 'c->dbg->buf' buffer and save
128KiB of RAM (or more if PEB size is larger). Indeed, currently we
allocate this memory even if the user never enables any self-check,
which is wasteful.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Instead of using pre-allocated 'c->dbg->buf' buffer in
'dump_lpt_leb()', dynamically allocate it when needed. The intend
is to get rid of the pre-allocated 'c->dbg->buf' buffer and save
128KiB of RAM (or more if PEB size is larger). Indeed, currently we
allocate this memory even if the user never enables any self-check,
which is wasteful.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Instead of using pre-allocated 'c->dbg->buf' buffer in
'dbg_check_ltab_lnum()', dynamically allocate it when needed. The
intend is to get rid of the pre-allocated 'c->dbg->buf' buffer and
save 128KiB of RAM (or more if PEB size is larger). Indeed,
currently we allocate this memory even if the user never enables
any self-check, which is wasteful.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Instead of using pre-allocated 'c->dbg->buf' buffer in
'scan_check_cb()', dynamically allocate it when needed. The intend
is to get rid of the pre-allocated 'c->dbg->buf' buffer and save
128KiB of RAM (or more if PEB size is larger). Indeed, currently we
allocate this memory even if the user never enables any self-check,
which is wasteful.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Instead of using pre-allocated 'c->dbg->buf' buffer in
'dbg_dump_leb()', dynamically allocate it when needed. The intend
is to get rid of the pre-allocated 'c->dbg->buf' buffer and save
128KiB of RAM (or more if PEB size is larger). Indeed, currently we
allocate this memory even if the user never enables any self-check,
which is wasteful.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Now that VFS check for inode->i_nlink == 0 and returns proper
error, remove similar check from file system
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Change the default UBIFS behavior WRT data CRC checking. Currently,
UBIFS checks data CRC when reading, which slows it down quite a bit,
and this is the default option. However, it looks like in average
user does not need this feature and would prefer faster read speed
over extra reliability. And this seems to be de-facto standard that
file-systems do not check data CRC every time they read from the
media.

Thus, make UBIFS default behavior so that it does not check data
CRC. This corresponds to the no_chk_data_crc mount option. Those users
who need extra protection can always enable it using the chk_data_crc
option.

Please, read more information about this feature here:
http://www.linux-mtd.infradead.org/doc/ubifs.html#L_checksummingSigned-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Remove debug message level and debug checks Kconfig options as they
proved to be useless anyway. We have sysfs interface which we can
use for fine-grained debugging messages and checks selection, see
Documentation/filesystems/ubifs.txt for mode details.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Improve debugging messages by printing the maximum index node size
on mount.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Running kernel 2.6.37, my PPC-based device occasionally gets an
order-2 allocation failure in UBIFS, which causes the root FS to
become unwritable:

kswapd0: page allocation failure. order:2, mode:0x4050
Call Trace:
[c787dc30] [c00085b8] show_stack+0x7c/0x194 (unreliable)
[c787dc70] [c0061aec] __alloc_pages_nodemask+0x4f0/0x57c
[c787dd00] [c0061b98] __get_free_pages+0x20/0x50
[c787dd10] [c00e4f88] ubifs_jnl_write_data+0x54/0x200
[c787dd50] [c00e82d4] do_writepage+0x94/0x198
[c787dd90] [c00675e4] shrink_page_list+0x40c/0x77c
[c787de40] [c0067de0] shrink_inactive_list+0x1e0/0x370
[c787de90] [c0068224] shrink_zone+0x2b4/0x2b8
[c787df00] [c0068854] kswapd+0x408/0x5d4
[c787dfb0] [c0037bcc] kthread+0x80/0x84
[c787dff0] [c000ef44] kernel_thread+0x4c/0x68

Similar problems were encountered last April by Tomasz Stanislawski:

http://patchwork.ozlabs.org/patch/50965/

This patch implements Artem's suggested fix: fall back to a
mutex-protected static buffer, allocated at mount time.  I tested it
by forcing execution down the failure path, and didn't see any ill
effects.

Artem: massaged the patch a little, improved it so that we'd not
allocate the write reserve buffer when we are in R/O mode.
Signed-off-by: NMatthew L. Creech <mlcreech@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

When recovering from unclean reboots UBIFS scans the journal and checks nodes.
If a corrupted node is found, UBIFS tries to check if this is the last node
in the LEB or not. This is is done by checking if there only 0xFF bytes
starting from the next min. I/O unit. However, since now we write in
c->max_write_size, we should actually check for 0xFFs starting from the
next max. write unit.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Switch write-buffers from 'c->min_io_size' to 'c->max_write_size' which
presumably has to be more write speed-efficient. However, when write-buffer
is synchronized, write only the the min. I/O units which contain the
data, do not write whole write-buffer. This is more space-efficient.

Additionally, this patch takes into account that the LEB might not start
from the max. write unit-aligned address.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Currently we assume write-buffer size is always min_io_size. But
this is about to change and write-buffers may be of variable size.
Namely, they will be of max_write_size at the beginning, but will
get smaller when we are approaching the end of LEB.

This is a preparation patch which introduces 'size' field in
the write-buffer structure which carries the current write-buffer
size.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Incorporate the LEB offset information into UBIFS. We'll use this
information in one of the next patches to figure out what are the
max. write size offsets relative to the PEB. So this patch is just
a preparation.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Incorporate maximum write size into the UBIFS description data
structure. This patch just introduces new 'c->max_write_size'
and 'c->max_write_shift' fields as a preparation for the following
patches.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

This is a minor patch which fixes the LEB number we print when
corrupted empty space is found.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Don't allow everybody to dump sensitive information about filesystems.
Signed-off-by: NVasiliy Kulikov <segoon@openwall.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>