d251ed27 "ubifs: fix sget races" left out the goto from this
error path so the static checkers complain that we're dereferencing
"sb" when it's an ERR_PTR.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

* allocate ubifs_info in ->mount(), fill it enough for sb_test() and
set ->s_fs_info to it in set() callback passed to sget().
* do *not* free it in ->put_super(); do that in ->kill_sb() after we'd
done kill_anon_super().
* don't free it in ubifs_fill_super() either - deactivate_locked_super()
done by caller when ubifs_fill_super() returns an error will take care
of that sucker.
* get rid of kludge with passing ubi to ubifs_fill_super() in ->s_fs_info;
we only need it in alloc_ubifs_info(), so ubifs_fill_super() will need
only ubifs_info.  Which it will find in ->s_fs_info just fine, no need to
reassign anything...

As the result, sb_test() becomes safe to apply to all superblocks that
can be found by sget() (and a kludge with temporary use of ->s_fs_info
to store a pointer to very different structure goes away).
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

preparation to ubifs sget() race fixes
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The free space fixup is currently initiated during mount after the call to
ubifs_write_master() which results in a write to PEBs; this has been observed
with the patch 'assert no fixup when writing a node' applied:

Move the free space fixup on mount to before the calls to
ubifs_recover_inl_heads() and ubifs_write_master(). This results in no
assertions with the previously mentioned patch applied.

Artem: tweaked the patch a bit
Signed-off-by: NBen Gardiner <bengardiner@nanometrics>
Reviewed-by: NMatthew L. Creech <mlcreech@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

The current 'mount_ubifs()' implementation does not initialize the LPT until the
the master node is marked dirty. Move the LPT initialization to before marking
the master node dirty. This is a preparation for the next patch which will move
the free-space-fixup check to before marking the master node dirty, because we
have to fix-up the free space before doing any writes.

Artem: massaged the patch and commit message.
Signed-off-by: NBen Gardiner <bengardiner@nanometrics.ca>
Reviewed-by: NMatthew L. Creech <mlcreech@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Journal heads are different in a way how UBIFS writes nodes there. All normal
journal heads receive grouped nodes, while the GC journal heads receives
ungrouped nodes. This patch adds a 'grouped' flag to 'struct ubifs_jhead' which
describes this property.

This patch is a preparation to a further recovery fix.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Tell the filesystem if we just updated timestamp (I_DIRTY_SYNC) or
anything else, so that the filesystem can track internally if it
needs to push out a transaction for fdatasync or not.

This is just the prototype change with no user for it yet.  I plan
to push large XFS changes for the next merge window, and getting
this trivial infrastructure in this window would help a lot to avoid
tree interdependencies.

Also remove incorrect comments that ->dirty_inode can't block.  That
has been changed a long time ago, and many implementations rely on it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

If a UBIFS filesystem is being mounted read-write, or is being remounted
from read-only to read-write, check for the "space_fixup" flag and fix
all LEBs containing empty space if necessary.

Artem: tweaked the patch a bit
Signed-off-by: NMatthew L. Creech <mlcreech@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

When re-mounting from R/O mode to R/W mode and the LEB count in the superblock
is not up-to date, because for the underlying UBI volume became larger, we
re-write the superblock. We allocate RAM for these purposes, but never free it.
So this is a memory leak, although very rare one.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Cc: stable@kernel.org

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>

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>

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>

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

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+]

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]

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>

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>

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 preparational patch which removes the 'c->always_chk_crc' which was
set during mounting and remounting to R/W mode and introduces 'c->mounting'
flag which is set when mounting. Now the 'c->always_chk_crc' flag is the
same as 'c->remounting_rw && c->mounting'.

This patch is a preparation for the next one which will need to know when we
are mounting and remounting to R/W mode, which is exactly what
'c->always_chk_crc' effectively is, but its name does not suite the
next patch. The other possibility would be to just re-name it, but then
we'd end up with less logical flags coverage.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

RCU free the struct inode. This will allow:

- Subsequent store-free path walking patch. The inode must be consulted for
  permissions when walking, so an RCU inode reference is a must.
- sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
  to take i_lock no longer need to take sb_inode_list_lock to walk the list in
  the first place. This will simplify and optimize locking.
- Could remove some nested trylock loops in dcache code
- Could potentially simplify things a bit in VM land. Do not need to take the
  page lock to follow page->mapping.

The downsides of this is the performance cost of using RCU. In a simple
creat/unlink microbenchmark, performance drops by about 10% due to inability to
reuse cache-hot slab objects. As iterations increase and RCU freeing starts
kicking over, this increases to about 20%.

In cases where inode lifetimes are longer (ie. many inodes may be allocated
during the average life span of a single inode), a lot of this cache reuse is
not applicable, so the regression caused by this patch is smaller.

The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
however this adds some complexity to list walking and store-free path walking,
so I prefer to implement this at a later date, if it is shown to be a win in
real situations. I haven't found a regression in any non-micro benchmark so I
doubt it will be a problem.
Signed-off-by: NNick Piggin <npiggin@kernel.dk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This is a bug-fix: when we unmount, and we are currently in R/O
mode because of an error - we do not sync write-buffers, which
means we also do not cancel write-buffer timers we may possibly
have armed. This patch fixes the issue.

The issue can easily be reproduced by enabling UBIFS failure debug
mode (echo 4 > /sys/module/ubifs/parameters/debug_tsts) and
unmounting as soon as a failure happen. At some point the system
oopses because we have an armed hrtimer but UBIFS is unmounted
already.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

This is a clean-up patch which:

1. Removes explicite 'hrtimer_cancel()' after 'ubifs_wbuf_sync()' in
   'ubifs_remount_ro()', because the timers will be canceled by
   'ubifs_wbuf_sync()', no need to cancel them for the second time.
2. Remove "if (c->jheads)" check from 'ubifs_put_super()', because
   at journal heads must always be allocated there, since we checked
   earlier that we were mounted R/W, and the olny situation when
   journal heads are not allocated is when mounter or re-mounted R/O.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

.get_sb is called on mounts with automatic fs detection too, so this
function should print an error if it cannot read the superblock in
debug mode only (new behaviour conforms the other fs types)
Signed-off-by: NSteffen Sledz <sledz@dresearch.de>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Commit 2fde99cb "UBIFS: mark VFS SB RO too"
introduced regression. This commit made UBIFS set the 'MS_RDONLY' flag in the
VFS superblock when it switches to R/O mode due to an error. This was done
to make VFS show the R/O UBIFS flag in /proc/mounts.

However, several places in UBIFS relied on the 'MS_RDONLY' flag and assume this
flag can only change when we re-mount. For example, 'ubifs_put_super()'.

This patch introduces new UBIFS flag - 'c->ro_mount' which changes only when
we re-mount, and preserves the way UBIFS was originally mounted (R/W or R/O).
This allows us to de-initialize UBIFS cleanly in 'ubifs_put_super()'.

This patch also changes all 'ubifs_assert(!c->ro_media)' assertions to
'ubifs_assert(!c->ro_media && !c->ro_mount)', because we never should write
anything if the FS was mounter R/O.

All the places where we test for 'MS_RDONLY' flag in the VFS SB were changed
and now we test the 'c->ro_mount' flag instead, because it preserves the
original UBIFS mount type, unlike the 'MS_RDONLY' flag.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

The R/O state may have various reasons:

1. The UBI volume is R/O
2. The FS is mounted R/O
3. The FS switched to R/O mode because of an error

However, in UBIFS we have only one variable which represents cases
1 and 3 - 'c->ro_media'. Indeed, we set this to 1 if we switch to
R/O mode due to an error, and then we test it in many places to
make sure that we stop writing as soon as the error happens.

But this is very unclean. One consequence of this, for example, is
that in 'ubifs_remount_fs()' we use 'c->ro_media' to check whether
we are in R/O mode because on an error, and we print a message
in this case. However, if we are in R/O mode because the media
is R/O, our message is bogus.

This patch introduces new flag - 'c->ro_error' which is set when
we switch to R/O mode because of an error. It also changes all
"if (c->ro_media)" checks to "if (c->ro_error)" checks, because
this is what the checks actually mean. We do not need to check
for 'c->ro_media' because if the UBI volume is in R/O mode, we
do not allow R/W mounting, and now writes can happen. This is
guaranteed by VFS. But it is good to double-check this, so this
patch also adds many "ubifs_assert(!c->ro_media)" checks.

In the 'ubifs_remount_fs()' function this patch makes a bit more
changes - it fixes the error messages as well.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

In 'mount_ubifs()', in case of 'ubifs_leb_unmap()' falure,
free allocated resources.
Signed-off-by: NMatthieu CASTET <matthieu.castet@parrot.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

The error code from 'ubifs_rcvry_gc_commit()' was ignored, so UBIFS
failed to recover and continued. Instead, we should refuse mounting
the file-system.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

This gives the filesystem more information about the writeback that
is happening.  Trond requested this for the NFS unstable write handling,
and other filesystems might benefit from this too by beeing able to
distinguish between the different callers in more detail.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NJoe Perches <joe@perches.com>
Cc: Artem Bityutskiy <dedekind@infradead.org>
Cc: Adrian Hunter <adrian.hunter@nokia.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch makes it possible to mount UBI character device
nodes, and use something like:

$ mount -t ubifs /dev/ubi_volume_name /mnt/ubifs

instead of the old restrictive 'nodev' semantics:

$ mount -t ubifs ubi0_0 /mnt/ubifs

[Comments and the patch were amended a bit by Artem]
Signed-off-by: NCorentin Chary <corentincj@iksaif.net>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

We do this automatically in get_sb_bdev() from the set_bdev_super()
callback. Filesystems that have their own private backing_dev_info
must assign that in ->fill_super().

Note that ->s_bdi assignment is required for proper writeback!
Acked-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

This enables us to track who does what and print info. Its main use
is catching dirty inodes on the default_backing_dev_info, so we can
fix that up.
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

This adds two new exported functions:

- writeback_inodes_sb(), which only attempts to writeback dirty inodes on
  this super_block, for WB_SYNC_NONE writeout.
- sync_inodes_sb(), which writes out all dirty inodes on this super_block
  and also waits for the IO to complete.
Acked-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Add one more check to UBIFS - a check that makes sure that there
are no data nodes beyond inode size. And few commantaries fixes
along the line.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Reviewed-by: NAdrian Hunter <Adrian.Hunter@nokia.com>