This patch adds another debugfs knob which switches UBIFS to R/O mode.
I needed it while trying to reproduce the 'first log node is not CS node'
bug. Without this debugfs knob you have to perform a power cut to repruduce
the bug. The knob is named 'ro_error' and all it does is it sets the
'ro_error' UBIFS flag which makes UBIFS disallow any further writes - even
write-back will fail with -EROFS. Useful for debugging.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@linux.intel.com>

Commit "818039c7 UBIFS: fix debugfs-less systems support" fixed one
regression but introduced a different regression - the debugfs is now always
compiled out. Root cause: IS_ENABLED() arguments should be used with the
CONFIG_* prefix.
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

Commit "f70b7e52 UBIFS: remove Kconfig debugging option" broke UBIFS and it
refuses to initialize if debugfs (CONFIG_DEBUG_FS) is disabled. I incorrectly
assumed that debugfs files creation function will return success if debugfs
is disabled, but they actually return -ENODEV. This patch fixes the issue.
Reported-by: NPaul Parsons <lost.distance@yahoo.com>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Tested-by: NPaul Parsons <lost.distance@yahoo.com>

We do not need this feature and to our shame it even was not working
and there was a bug found very recently.
	-- Artem Bityutskiy

Without the data type hint UBI2 (fastmap) will be easier to implement.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

This patch removes the 'dbg_err()' macro and we now use 'ubifs_err()' instead.
The idea of 'dbg_err()' was to compile out some error message to make the
binary a bit smaller - but I think it was a bad idea.
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

Have the debugging stuff always compiled-in instead. It simplifies maintanance
a lot.
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

This commit re-names all functions which dump something from "dbg_dump_*()" to
"ubifs_dump_*()". This is done for consistency with UBI and because this way it
will be more logical once we remove the debugging sompilation option.
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

In case of errors we almost always need the stack dump - it makes no sense
to compile it out. Remove the 'dbg_dump_stack()' function completely.
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

Remove the usage of the 'dbg_lock' spinlock from 'dbg_err()' and make
it static.
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

Most of the time we use the dumping function to dump something in case
of error. We use 'KERN_DEBUG' printk level, and the drawback is that users
do not see them in the console, while they see the other error messages
in the console. The result is that they send bug reports which does not
contain a lot of useful information. This patch changes the printk level
of the dump functions to 'KERN_ERR' to correct the situation.

I documented it in the MTD web site that people have to send the 'dmesg' output
when submitting bug reposts - it did not help.
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

Before commit 56e46742 we have had locking
around all printing macros and we could use static buffers for creating
key strings and printing them. However, now we do not have that locking and
we cannot use static buffers. This commit removes the old DBGKEY() macros
and introduces few new helper macros for printing debugging messages plus
a key at the end. Thankfully, all the messages are already structures in
a way that the key is printed in the end.
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

Switch to 'snprintf()' which is more secure and reliable. This is also a
preparation to the subsequent key printing fixes.
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

This commit adds 'dbg_dump_sleb()' helper function to dump scanning
information.
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@intel.com>

This patch cleans-up and improves the power cut testing:

1. Kill custom 'simple_random()' function and use 'random32()' instead.
2. Make timeout larger
3. When cutting the buffer - fill the end with random data sometimes, not
   only with 0xFFs.
4. Some times cut in the middle of the buffer, not always at the end.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Since the recovery testing is effectively about emulating power cuts by UBIFS,
use "power cut" as the base term for all the related variables and name them
correspondingly. This is just a minor clean-up for the sake of readability.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

This is a clean-up of the power-cut emulation code - remove the custom list of
superblocks which we maintained to find the superblock by the UBI volume
descriptor. We do not need that crud any longer, because now we can get the
superblock as a function argument.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Now when we use UBIFS helpers for all the I/O, we can remove the horrible hack
of re-defining UBI I/O functions.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

This patch contains several minor clean-up and preparational cahnges.

1. Remove 'dbg_read()', 'dbg_write()', 'dbg_change()', and 'dbg_leb_erase()'
   functions as they are not used.
2. Remove 'dbg_leb_read()' and 'dbg_is_mapped()' as they are not really needed,
   it is fine to let reads go through in failure mode.
3. Rename 'offset' argument to 'offs' to be consistent with the rest of UBIFS
   code.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Now we have per-FS (superblock) debugfs knobs, but they have one drawback - you
have to first mount the FS and only after this you can switch self-checks
on/off. But often we want to have the checks enabled during the mount.
Introduce global debugging knobs for this purpose.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Separate out pieces of code from the debugfs file read/write functions and
create separate 'interpret_user_input()'/'provide_user_output()' helpers. These
helpers will be needed in one of the following patches, so this is just a
preparational change.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Move 'dbg_debugfs_init()' and 'dbg_debugfs_exit()' functions which initialize
debugfs for whole UBIFS subsystem below the code which initializes debugfs for
a particular UBIFS instance. And do the same for 'ubifs_debugging_init()' and
'ubifs_debugging_exit()' functions. This layout is a bit better for the next
patches, so this is just a preparation.

Also, rename 'open_debugfs_file()' into 'dfs_file_open()' for consistency.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

When we are testing UBIFS recovery, it is better to print in which eraseblock
we are going to fail. Currently UBIFS prints it only if recovery debugging
messages are enabled, but this is not very practical. So change 'dbg_rcvry()'
messages to 'ubifs_warn()' messages.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

UBIFS has many built-in self-check functions which can be enabled using the
debug_chks module parameter or the corresponding sysfs file
(/sys/module/ubifs/parameters/debug_chks). However, this is not flexible enough
because it is not per-filesystem. This patch moves this to debugfs interfaces.

We already have debugfs support, so this patch just adds more debugfs files.
While looking at debugfs support I've noticed that it is racy WRT file-system
unmount, and added a TODO entry for that. This problem has been there for long
time and it is quite standard debugfs PITA. The plan is to fix this later.

This patch is simple, but it is large because it changes many places where we
check if a particular type of checks is enabled or disabled.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

We have too many different debugging checks - lessen the amount by merging all
index-related checks into one. At the same time, move the "force in-the-gap"
test to the "index checks" class, because it is too heavy for the "general"
class.

This patch merges TNC, Old index, and Index size check and calles this just
"index checks".
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

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>

Add 'const struct ubifs_info *c' parameter to 'dbg_check_synced_i_size()'
function because we'll need it in the next patch when we switch to debugfs.
So this patch is just a preparation.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Since this function is not only about size checking, rename it to
'dbg_check_dir()'.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Teach 'dbg_dump_inode()' dump directory entries for directory inodes.
This requires few additional changes:
1. The 'c' argument of 'dbg_dump_inode()' cannot be const any more.
2. Users of 'dbg_dump_inode()' should not have 'tnc_mutex' locked.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

This patch lessens the 'struct ubifs_debug_info' size by 90 bytes by
allocating less bytes for the debugfs root directory name. It introduces macros
for the name patter an length instead of hard-coding 100 bytes. It also makes
UBIFS use 'snprintf()' and teaches it to gracefully catch situations when the
name array is too short.

Additionally, this patch makes 2 unrelated changes - I just thought they do not
deserve separate commits: simplifies 'ubifs_assert()' for non-debugging case
and makes 'dbg_debugfs_init()' properly verify debugfs return code which may be
an error code or NULL, so we should you 'IS_ERR_OR_NULL()' instead of
'IS_ERR()'.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Switch to debugging using dynamic printk (pr_debug()). There is no good reason
to carry custom debugging prints if there is so cool and powerful generic
dynamic printk infrastructure, see Documentation/dynamic-debug-howto.txt. With
dynamic printks we can switch on/of individual prints, per-file, per-function
and per format messages. This means that instead of doing old-fashioned

echo 1 > /sys/module/ubifs/parameters/debug_msgs

to enable general messages, we can do:

echo 'format "UBIFS DBG gen" +ptlf' > control

to enable general messages and additionally ask the dynamic printk
infrastructure to print process ID, line number and function name. So there is
no reason to keep UBIFS-specific crud if there is more powerful generic thing.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

The 'space_fixup' flag can be set in the superblock of a new filesystem by
mkfs.ubifs to indicate that any eraseblocks with free space remaining should be
fixed-up the first time it's mounted (after which the flag is un-set). This
means that the UBIFS image has been flashed by a "dumb" flasher and the free
space has been actually programmed (writing all 0xFFs), so this free space
cannot be used. UBIFS fixes the free space up by re-writing the contents of all
LEBs with free space using the atomic LEB change UBI operation.

Artem: improved commit message, add some more commentaries to the code.
Signed-off-by: NMatthew L. Creech <mlcreech@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

When the debugging self-checks are enabled, we go trough whole file-system
after mount and check/validate every single node referred to by the index.
This is implemented by the 'dbg_check_filesystem()' function. However, this
function fails if we mount "unclean" file-system, i.e., if we mount the
file-system after a power cut. It fails with the following symptoms:

UBIFS DBG (pid 8171): ubifs_recover_size: ino 937 size 3309925 -> 3317760
UBIFS: recovery deferred
UBIFS error (pid 8171): check_leaf: data node at LEB 1000:0 is not within inode size 3309925

The reason of failure is that recovery fixed up the inode size in memory, but
not on the flash so far. So the value on the flash is incorrect so far,
and would be corrected when we re-mount R/W. But 'check_leaf()' ignores
this fact and tries to validate the size of the on-flash inode, which is
incorrect, so it fails.

This patch teaches the checking code to look at the VFS inode cache first,
and if there is the inode in question, use that inode instead of the inode
on the flash media. This fixes the issue.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

This patch is a tiny improvement which removes few bytes of code.
UBIFS debugfs files are non-seekable and the file position is ignored,
so do not increase it in the write handler.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

The 'dbg_dump_lprop()' is trying to detect journal head LEBs when printing,
so it looks at the write-buffers. However, if we are in R/O mode, we
de-allocate the write-buffers, so 'dbg_dump_lprop()' oopses. This patch fixes
the issue.

Note, this patch is not critical, it is only about the debugging code path, and
it is unlikely that anyone but UBIFS developers would ever hit this issue.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

When the debugging failure emulation is enabled and UBIFS decides to
emulate an I/O error, it uses EIO error code. In which case UBIFS
switches into R/O mode later on. The for the user-space is that when
a failure is emulated, the file-system sometimes returns EIO and
sometimes EROFS. This makes it more difficult to implement user-space
tests for the failure mode. Let's be consistent and return EROFS in
all the cases.

This patch is an improvement for the debugging code and does not affect
the functionality at all.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

UBIFS can force itself to use the 'in-the-gaps' commit method - the last resort
method which is normally invoced very very rarely. Currently this "force
int-the-gaps" debugging feature is a separate test mode. But it is a bit saner
to make it to be the "general" self-test check instead.

This patch is just a clean-up which should make the debugging code look a bit
nicer and easier to use - we have way too many debugging options.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

This patch improves the 'dbg_check_space_info()' function which checks
whether the amount of space before re-mounting and after re-mounting
is the same (remounting from R/O to R/W modes and vice-versa).

The problem is that 'dbg_check_space_info()' does not save the budgeting
information before re-mounting, so when an error is reported, we do not
know why the amount of free space changed.

This patches makes the following changes:

1. Teaches 'dbg_dump_budg()' function to accept a 'struct ubifs_budg_info'
   argument and print out the this argument. This way we may ask it to
   print any saved budgeting info, no only the current one.
2. Accordingly changes all the callers of 'dbg_dump_budg()' to comply with
   the changed interface.
3. Introduce a 'saved_bi' (saved budgeting info) field to
   'struct ubifs_debug_info' and save the budgeting info before re-mounting
   there.
4. Change 'dbg_check_space_info()' and make it print both old and new
   budgeting information.
5. Additionally, save 'c->igx_gc_cnt' and print it if and error happens. This
   value contributes to the amount of free space, so we have to print it.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Re-arrange the budget dump and make sure we first dump all
the 'struct ubifs_budg_info' fields, and then the other information.
Additionally, print the 'uncommitted_idx' variable.

This change is required for to the following dumping function
enhancement where it will be possible to dump saved
'struct ubifs_budg_info' objects, not only the current one.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

The current 'dbg_dump_budg()' calling convention is that the
'c->space_lock' spinlock is held. However, none of the callers
actually use it from contects which have 'c->space_lock' locked,
so all callers have to explicitely lock and unlock the spinlock.
This is not very sensible convention. This patch changes it and
makes 'dbg_dump_budg()' lock the spinlock instead of imposing this
to the callers. This simplifies the code a little.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

This patch separates out all the budgeting-related information
from 'struct ubifs_info' to 'struct ubifs_budg_info'. This way the
code looks a bit cleaner. However, the main driver for this is
that we want to save budgeting information and print it later,
so a separate data structure for this is helpful.

This patch is a preparation for the further debugging output
improvements.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>