This patch introduces helper functions for all debugging checks, so instead of
doing

if (!(ubifs_chk_flags & UBIFS_CHK_GEN))

we now do

if (!dbg_is_chk_gen(c))

This is a preparation to further changes where the flags will go away, and
we'll need to only change the helper functions, but the code which utilizes
them won't be touched.

At the same time this patch removes 'dbg_force_in_the_gaps()',
'dbg_force_in_the_gaps_enabled()', and dbg_failure_mode helpers for
consistency.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

The UBIFS lpt tree is in many aspects similar to the TNC tree, and we have
similar flags for these trees. And by mistake we use the COW_ZNODE flag for
LPT in some places, instead of the right flag COW_CNODE. And this works
only because these two constants have the same value.

This patch makes all the LPT code to use COW_CNODE and also changes COW_CNODE
constant value to make sure we do not misuse the flags any more.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Try to improve UBIFS testing coverage by randomly picking LEBs to
store in lsave, rather than picking them optimally. Create a debugging
version of 'populate_lsave()' for these purposes and enable it when
general debugging self-checks are enabled.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Fix several minor stylistic issues:
* lines longer than 80 characters
* space before closing parenthesis ')'
* spaces in the indentations
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>

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>

Function pnode_lookup may return ERR_PTR(...). Check for it.
Signed-off-by: NVasiliy Kulikov <segooon@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Use ERR_CAST(x) rather than ERR_PTR(PTR_ERR(x)).  The former makes more
clear what is the purpose of the operation, which otherwise looks like a
no-op.
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

When writing lprop nodes, do not forget to set @from to 0 when
switching the LEB. This fixes the following bug:

UBIFS error (pid 27768): ubifs_leb_write: writing -15456 bytes at 16:15880, error -22
UBIFS error (pid 27768): do_commit: commit failed, error -22
UBIFS warning (pid 27768): ubifs_ro_mode: switched to read-only mode, error -22
Pid: 27768, comm: freespace Not tainted 2.6.29-rc4-ubifs-2.6 #43
Call Trace:
 [<ffffffffa00c46d6>] ubifs_ro_mode+0x54/0x56 [ubifs]
 [<ffffffffa00cfa16>] do_commit+0x4f5/0x50a [ubifs]
 [<ffffffffa00cfae7>] ubifs_run_commit+0xbc/0xdb [ubifs]
 [<ffffffffa00d42b9>] ubifs_budget_space+0x742/0x9ed [ubifs]
 [<ffffffff812daf45>] ? __mutex_lock_common+0x361/0x3ae
 [<ffffffffa00bc437>] ? ubifs_write_begin+0x18d/0x44c [ubifs]
 [<ffffffffa00bc5cb>] ubifs_write_begin+0x321/0x44c [ubifs]
 [<ffffffff8106222b>] ? trace_hardirqs_on_caller+0x1f/0x14d
 [<ffffffff81097ce2>] generic_file_buffered_write+0x12f/0x2d9
 [<ffffffff8109828d>] __generic_file_aio_write_nolock+0x261/0x295
 [<ffffffff81098aff>] generic_file_aio_write+0x69/0xc5
 [<ffffffffa00bb914>] ubifs_aio_write+0x14c/0x19e [ubifs]
 [<ffffffff810c8f42>] do_sync_write+0xe7/0x12d
 [<ffffffff81055378>] ? autoremove_wake_function+0x0/0x38
 [<ffffffff81149edc>] ? security_file_permission+0x11/0x13
 [<ffffffff810c9827>] vfs_write+0xab/0x105
 [<ffffffff810c9945>] sys_write+0x47/0x6f
 [<ffffffff8100c35b>] system_call_fastpath+0x16/0x1b
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

The debugging function dbg_chk_lpt_sz() was not working
correctly for small min_io_unit size e.g. NOR flash.
Signed-off-by: NAdrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

The function to traverse and dirty the LPT was still not
dirtying all nodes, with the result that the LPT could
run out of space.
Signed-off-by: NAdrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

These are mostly long lines and wrong indentation warning
fixes. But also there are two volatile variables and
checkpatch.pl complains about them:

WARNING: Use of volatile is usually wrong: see Documentation/volatile-considered-harmful.txt
+       volatile int gc_seq;

WARNING: Use of volatile is usually wrong: see Documentation/volatile-considered-harmful.txt
+       volatile int gced_lnum;

Well, we anyway use smp_wmb() for c->gc_seq and c->gced_lnum, so
these 'volatile' modifiers can be just dropped.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

It is useful to know how we got to the checking function when
hunting the bugs.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Do not forget to check whether lpt debugging is enabled before
running the check functions. This commit also makes some spelling
fixes.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Introduce a new data structure which contains all debugging
stuff inside. This is cleaner than having debugging stuff
directly in 'c'.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

The LPT may have gaps in it because initially empty LEBs
are not added by mkfs.ubifs - because it does not know how
many there are.  Then UBIFS allocates empty LEBs in the
reverse order that they are discovered i.e. they are
added to, and removed from, the front of a list.  That
creates a gap in the middle of the LPT.

The function dirtying the LPT tree (for the purpose of
small model garbage collection) assumed that a gap could
only occur at the very end of the LPT and stopped dirtying
prematurely, which in turn resulted in the LPT running
out of space - something that is designed to be impossible.
Signed-off-by: NAdrian Hunter <ext-adrian.hunter@nokia.com>

'is_a_node()' function was reading from a buffer before
checking the buffer length, resulting in an OOPS as
follows:

BUG: unable to handle kernel paging request at f8f74002
IP: [<f8f9783f>] :ubifs:ubifs_unpack_bits+0xca/0x233
*pde = 19e95067 *pte = 00000000
Oops: 0000 [#1] PREEMPT SMP
Modules linked in: ubifs ubi mtdchar bio2mtd mtd brd video output
[last unloaded: mtd]

Pid: 6414, comm: integck Not tainted (2.6.27-rc6ubifs34 #23)
EIP: 0060:[<f8f9783f>] EFLAGS: 00010246 CPU: 0
EIP is at ubifs_unpack_bits+0xca/0x233 [ubifs]
EAX: 00000000 EBX: f6090630 ECX: d9badcfc EDX: 00000000
ESI: 00000004 EDI: f8f74002 EBP: d9badcec ESP: d9badcc0
 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process integck (pid: 6414, ti=d9bac000 task=f727dae0 task.ti=d9bac000)
Stack: 00000006 f7306240 00000002 00000000 d9badcfc d9badd00 0000001c 00000000
       f6090630 f6090630 f8f74000 d9badd10 f8fa1cc9 00000000 f8f74002 00000000
       f8f74002 f60fe128 f6090630 f8f74000 d9badd68 f8fa1e46 00000000 0001e000
Call Trace:
 [<f8fa1cc9>] ? is_a_node+0x30/0x90 [ubifs]
 [<f8fa1e46>] ? dbg_check_ltab+0x11d/0x5bd [ubifs]
 [<f8fa388f>] ? ubifs_lpt_start_commit+0x42/0xed3 [ubifs]
 [<c038e76a>] ? mutex_unlock+0x8/0xa
 [<f8f9625d>] ? ubifs_tnc_start_commit+0x1c8/0xedb [ubifs]
 [<f8f8d90b>] ? do_commit+0x187/0x523 [ubifs]
 [<c038e76a>] ? mutex_unlock+0x8/0xa
 [<f8f7ca17>] ? bud_wbuf_callback+0x22/0x28 [ubifs]
 [<f8f8dd1d>] ? ubifs_run_commit+0x76/0xc0 [ubifs]
 [<f8f8032c>] ? ubifs_sync_fs+0xd2/0xe6 [ubifs]
 [<c01a2e97>] ? vfs_quota_sync+0x0/0x17e
 [<c01a5ba6>] ? quota_sync_sb+0x26/0xbb
 [<c01a2e97>] ? vfs_quota_sync+0x0/0x17e
 [<c01a5c5d>] ? sync_dquots+0x22/0x12c
 [<c0173d1b>] ? __fsync_super+0x19/0x68
 [<c0173d75>] ? fsync_super+0xb/0x19
 [<c0174065>] ? generic_shutdown_super+0x22/0xe7
 [<c01a31fc>] ? vfs_quota_off+0x0/0x5fd
 [<f8f7cf4d>] ? ubifs_kill_sb+0x31/0x35 [ubifs]
 [<c01741f9>] ? deactivate_super+0x5e/0x71
 [<c0187610>] ? mntput_no_expire+0x82/0xe4
 [<c0187905>] ? sys_umount+0x4c/0x2f6
 [<c0187bc8>] ? sys_oldumount+0x19/0x1b
 [<c0103b71>] ? sysenter_do_call+0x12/0x25
 =======================
Code: c1 f8 03 8d 04 07 8b 4d e8 89 01 8b 45 e4 89 10 89 d8 89 f1 d3 e8 85 c0
      74 07 29 d6 83 fe 20 75 2a 89 d8 83 c4 20 5b 5e 5f 5d
EIP: [<f8f9783f>] ubifs_unpack_bits+0xca/0x233 [ubifs] SS:ESP 0068:d9badcc0
---[ end trace 1f02572436518c13 ]---
Signed-off-by: NAdrian Hunter <ext-adrian.hunter@nokia.com>

Also add debugging checks for LPT size and separate
out c->check_lpt_free from unrelated bitfields.
Signed-off-by: NAdrian Hunter <ext-adrian.hunter@nokia.com>

This is a new flash file system. See
http://www.linux-mtd.infradead.org/doc/ubifs.htmlSigned-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NAdrian Hunter <ext-adrian.hunter@nokia.com>