Fastmap need access to various WL data structures as
fastmap tightly depends on WL.
To make the access less invasive add accessor functions.
Signed-off-by: Richard Weinberger <richard@nod.at>

Fastmap is tightly connected to the WL sub-system, many fastmap-specific
functionslive in wl.c.
To get rid of most #ifdefs in wl.c move this functions into a new file
and include it into wl.c
Signed-off-by: Richard Weinberger <richard@nod.at>

If fm_debug is set fastmap debugging is enabled by default.
This is useful if one wants to debug fastmap on an UBI device
with serves the rootfs.
The the UBI attach mechanism runs long before debugfs can be mounted
and chk_fastmap set.
Signed-off-by: Richard Weinberger <richard@nod.at>

...instead of generic self checking.
Signed-off-by: Richard Weinberger <richard@nod.at>

This self check allows Fastmap to detect absent PEBs while
writing a new fastmap to the MTD device.
It will help to find implementation issues in Fastmap.
Signed-off-by: Richard Weinberger <richard@nod.at>

In some error paths the WL sub-system gives up on a PEB
and frees it's ubi_wl_entry struct but does not set
the entry in ubi->lookuptbl to NULL.
Fastmap can stumble over such a stale pointer as it uses
ubi->lookuptbl to find all PEBs.

Fix this by introducing a new helper function which free()s
a WL entry and removes the reference from the lookup table.
Signed-off-by: Richard Weinberger <richard@nod.at>

Don't update the fastmap upon detach if fastmap checking is enabled.
This is poor men's power cut testing feature. :-)
Signed-off-by: Richard Weinberger <richard@nod.at>

Using this debugfs knob fastmap self checks can be controlled.
Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Tanya Brokhman <tlinder@codeaurora.org>

If UBI is unable to write the fastmap to the device
we have make sure that upon next attach UBI will fall
back to scanning mode.
In case we cannot ensure that they only thing we can do
is falling back to read-only mode.

The current error handling code is not powercut proof.
It could happen that a powercut while invalidating would
lead to a state where an too old fastmap could be used upon
attach.
This patch addresses the issue by writing a fake fastmap
super block to a fresh PEB instead of reerasing the existing one.
The fake fastmap super block will UBI case to do a full scan.
Signed-off-by: Richard Weinberger <richard@nod.at>

The current code assumes that each fastmap has the same amount of PEBs.
So far this is true but will change soon.
Signed-off-by: Richard Weinberger <richard@nod.at>

a) Rename ubi->fm_sem to ubi->fm_eba_sem as this semaphore
protects EBA changes.
b) Turn ubi->fm_mutex into a rw semaphore. It will still serialize
fastmap writes but also ensures that ubi_wl_put_peb() is not
interrupted by a fastmap write. We use a rw semaphore to allow
ubi_wl_put_peb() still to be executed in parallel if no fastmap
write is happening.
Signed-off-by: Richard Weinberger <richard@nod.at>

If we set it for dynamic ones we might confuse various self checks.
Signed-off-by: Richard Weinberger <richard@nod.at>

ubi_wl_get_peb() returns a fresh PEB which can be used by
user of UBI. Due to the pool logic fastmap will correctly
map this PEB upon attach time because it will be scanned.

If a new fastmap is written (due to heavy parallel io)
while the before the fresh PEB is assigned to the EBA table
it will not be scanned as it is no longer in the pool.
So, the race window exists between ubi_wl_get_peb()
and the EBA table assignment.
We have to make sure that no new fastmap can be written
while that.

To ensure that ubi_wl_get_peb() will grab ubi->fm_sem in read mode
and the user of ubi_wl_get_peb() has to release it after the PEB
got assigned.
Signed-off-by: Richard Weinberger <richard@nod.at>

If a LEB is unmapped we have to decrement leb_count as well.
Signed-off-by: Richard Weinberger <richard@nod.at>

Don't use a fixed size for the WL pool.
Make it instead 50% of the user pool.
We don't make it 100% as it is not as heavily used as the user pool.
Signed-off-by: Richard Weinberger <richard@nod.at>

We have to switch to ro mode to guarantee that upon next UBI attach
all data is consistent.
Signed-off-by: Richard Weinberger <richard@nod.at>

This logic is in vain as we treat protected PEBs also as used, so this
case must not happen.
If a PEB is found which is in the EBA table but not known as used
has to be issued as fatal error.
Signed-off-by: Richard Weinberger <richard@nod.at>

It is legal to have PEBs left in the used list.
This can happen if UBI copies a PEB and a powercut happens
between writing a new fastmap and adding this PEB into the EBA table.
In this case the old PEB will be used.
Signed-off-by: Richard Weinberger <richard@nod.at>

This function a) requests a new PEB, b) writes data to it,
c) returns the old PEB and d) registers the new PEB in the EBA table.

For the non-fastmap case this works perfectly fine and is powercut safe.
Is fastmap enabled this can lead to issues.
If a new fastmap is written between a) and c) the freshly requested PEB
is no longer in a pool and will not be scanned upon attaching.
If now a powercut happens between c) and d) the freshly requested PEB
will not be scanned and the old one got already scheduled for erase.
After attaching the EBA table will point to a erased PEB.

Fix this issue by swapping steps c) and d).
Signed-off-by: Richard Weinberger <richard@nod.at>

There is always exactly one ubi_attach_info object allocated,
therefore we don't have to care about the name.
Signed-off-by: Richard Weinberger <richard@nod.at>

Currently we leak a few ubi_ainf_pebs while attaching.
Signed-off-by: Richard Weinberger <richard@nod.at>

There is no need to switch to ro mode if ubi_update_fastmap() fails.
Also get rid of the ifdef.
Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Tanya Brokhman <tlinder@codeaurora.org>

...such that we can implement NOP variants of some functions.
This will help to reduce fastmap specific ifdefs in other c files.
Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Tanya Brokhman <tlinder@codeaurora.org>

If ubi_update_fastmap() fails notify the user.
This is not a hard error as ubi_update_fastmap() makes sure that upon failure
the current on-flash fastmap will no be used upon next UBI attach.
Signed-off-by: Richard Weinberger <richard@nod.at>

Add a ubi_fastmap_close() to free all resources used by fastmap
at WL shutdown.
Signed-off-by: Richard Weinberger <richard@nod.at>
Tested-by: Guido Martínez <guido@vanguardiasur.com.ar>
Reviewed-by: Guido Martínez <guido@vanguardiasur.com.ar>

There is no need to allocate new ones every time, we can reuse
the existing ones.
This makes the code cleaner and more easy to follow.
Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Tanya Brokhman <tlinder@codeaurora.org>
Reviewed-by: Guido Martínez <guido@vanguardiasur.com.ar>

Currently ubi_refill_pools() first fills the first and then
the second one.
If only very few free PEBs are available the second pool can get
zero PEBs.
Change ubi_refill_pools() to distribute free PEBs fair between
all pools.
Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Guido Martínez <guido@vanguardiasur.com.ar>

Make it two functions, wl_get_wle() and wl_get_peb().
wl_get_peb() works exactly like __wl_get_peb() but wl_get_wle()
does not call produce_free_peb().
While refilling the fastmap user pool we cannot release ubi->wl_lock
as produce_free_peb() does.
Hence the fastmap logic uses now wl_get_wle().
Signed-off-by: Richard Weinberger <richard@nod.at>

ubi_wl_get_peb() has two problems, it reads the pool
size and usage counters without any protection.
While reading one value would be perfectly fine it reads multiple
values and compares them. This is racy and can lead to incorrect
pool handling.
Furthermore ubi_update_fastmap() is called without wl_lock held,
before incrementing the used counter it needs to be checked again.
It could happen that another thread consumed all PEBs from the
pool and the counter goes beyond ->size.
Signed-off-by: Richard Weinberger <richard@nod.at>

...otherwise the deferred work might run after datastructures
got freed and corrupt memory.
Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Guido Martínez <guido@vanguardiasur.com.ar>

If the WL pool runs out of PEBs we schedule a fastmap write
to refill it as soon as possible.
Ensure that only one at a time is scheduled otherwise we might end in
a fastmap write storm because writing the fastmap can schedule another
write if bitflips are detected.
Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Tanya Brokhman <tlinder@codeaurora.org>
Reviewed-by: Guido Martínez <guido@vanguardiasur.com.ar>

The kerneldoc for @vid_hdr_aloffset continues onto a second line, but
this is not obvious, because the second line isn't indented, and it
begins with '@'.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

The comparison from the previous line seems to have been erroneously
(partially) copied-and-pasted onto the next. The second line should be
checking req.bytes, not req.lnum.

Coverity CID #139400

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
[rw: Fixed comparison]
Signed-off-by: Richard Weinberger <richard@nod.at>

In some of the 'out_not_moved' error paths, lnum may be used
uninitialized. Don't ignore the warning; let's fix it.

This uninitialized variable doesn't have much visible effect in the end,
since we just schedule the PEB for erasure, and its LEB number doesn't
really matter (it just gets printed in debug messages). But let's get it
straight anyway.

Coverity CID #113449

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

If aeb->len >= vol->reserved_pebs, we should not be writing aeb into the
PEB->LEB mapping.

Caught by Coverity, CID #711212.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

We are completely discarding the earlier value of 'bitflips', which
could reflect a bitflip found in ubi_io_read_vid_hdr(). Let's use the
bitwise OR of header and data 'bitflip' statuses instead.

Coverity CID #1226856

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

In the case where we have more than one volumes on different UBI
devices, it may be not that easy to tell which volume prints the
messages.  Add ubi number and volume id in ubifs_msg/warn/error
to help debug. These two values are passed by struct ubifs_info.

For those where ubifs_info is not initialized yet, ubifs_* is
replaced by pr_*. For those where ubifs_info is not avaliable,
ubifs_info is passed to the calling function as a const parameter.

The output looks like,

[   95.444879] UBIFS (ubi0:1): background thread "ubifs_bgt0_1" started, PID 696
[   95.484688] UBIFS (ubi0:1): UBIFS: mounted UBI device 0, volume 1, name "test1"
[   95.484694] UBIFS (ubi0:1): LEB size: 126976 bytes (124 KiB), min./max. I/O unit sizes: 2048 bytes/2048 bytes
[   95.484699] UBIFS (ubi0:1): FS size: 30220288 bytes (28 MiB, 238 LEBs), journal size 1523712 bytes (1 MiB, 12 LEBs)
[   95.484703] UBIFS (ubi0:1): reserved for root: 1427378 bytes (1393 KiB)
[   95.484709] UBIFS (ubi0:1): media format: w4/r0 (latest is w4/r0), UUID 40DFFC0E-70BE-4193-8905-F7D6DFE60B17, small LPT model
[   95.489875] UBIFS (ubi1:0): background thread "ubifs_bgt1_0" started, PID 699
[   95.529713] UBIFS (ubi1:0): UBIFS: mounted UBI device 1, volume 0, name "test2"
[   95.529718] UBIFS (ubi1:0): LEB size: 126976 bytes (124 KiB), min./max. I/O unit sizes: 2048 bytes/2048 bytes
[   95.529724] UBIFS (ubi1:0): FS size: 19808256 bytes (18 MiB, 156 LEBs), journal size 1015809 bytes (0 MiB, 8 LEBs)
[   95.529727] UBIFS (ubi1:0): reserved for root: 935592 bytes (913 KiB)
[   95.529733] UBIFS (ubi1:0): media format: w4/r0 (latest is w4/r0), UUID EEB7779D-F419-4CA9-811B-831CAC7233D4, small LPT model

[  954.264767] UBIFS error (ubi1:0 pid 756): ubifs_read_node: bad node type (255 but expected 6)
[  954.367030] UBIFS error (ubi1:0 pid 756): ubifs_read_node: bad node at LEB 0:0, LEB mapping status 1
Signed-off-by: Sheng Yong <shengyong1@huawei.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

Directly return recover_head() and ubifs_leb_unmap()
instead of storing value in err and testing it.
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

Change 'comress' to 'compress'
Change 'inteval' to 'interval'
Change 'disabe' to 'disable'
Change 'nenver' to 'never'
Signed-off-by: Yannick Guerrini <yguerrini@tomshardware.fr>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

The commits 781c5717 ("UBIFS: intialize LPT earlier") and 09801194 ("UBIFS:
fix-up free space earlier") move some initialization before marking the
master node dirty. But the modification changes the conditions of writing
master.

If unclean umount happens, ubifs may fail when mounting. But trying to
mount it will write new master nodes on the flash. This is useless but
increasing sqnum. So check need_recovery before writing master node, and
don't create new master node if filesystem needs recovery.

The behavour of the bug shows at:
http://lists.infradead.org/pipermail/linux-mtd/2015-February/057712.htmlSigned-off-by: Sheng Yong <shengyong1@huawei.com>
Reviewed-by: Ben Gardiner <ben.l.gardiner@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>