fs: push rcu_barrier() from deactivate_locked_super() to filesystems

There's no reason to call rcu_barrier() on every
deactivate_locked_super().  We only need to make sure that all delayed rcu
free inodes are flushed before we destroy related cache.

Removing rcu_barrier() from deactivate_locked_super() affects some fast
paths.  E.g.  on my machine exit_group() of a last process in IPC
namespace takes 0.07538s.  rcu_barrier() takes 0.05188s of that time.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
UBIFS: fix use of freed ubifs_orphan objects

The last orphan in the cnext list has its cnext set to NULL. Because
of that, ubifs_delete_orphan assumes that it is not on the cnext list
and frees it immediately instead of adding it to the dnext list. The
freed orphan is later modified by write_orph_node.

This can cause various inconsistencies including directory entries
that cannot be removed and this error:

UBIFS error (pid 20685): layout_cnodes: LPT out of space at LEB 14:129009 needing 17, done_ltab 1, done_lsave 1

This is a regression introduced by
"7074e5eb UBIFS: remove invalid reference to list iterator variable".

This change adds an explicit flag to ubifs_orphan indicating whether
it is pending commit.

Signed-off-by: Adam Thomas <adamthomas1111@gmail.com>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org # v3.6+
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBIFS: fix double free of ubifs_orphan objects

The last orphan in the dnext list has its dnext set to NULL. Because
of that, ubifs_delete_orphan assumes that it is not on the dnext list
and frees it immediately instead ignoring it as a second delete. The
orphan is later freed again by erase_deleted.

This change adds an explicit flag to ubifs_orphan indicating whether
it is pending delete.

Signed-off-by: Adam Thomas <adamthomas1111@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: stable@vger.kernel.org
ubifs: wait for page writeback to provide stable pages

When stable pages are required, we have to wait if the page is just
going to disk and we want to modify it.  Add proper callback to
ubifs_vm_page_mkwrite().

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
UBIFS: remove __DATE__ and __TIME__

This tag is useless and it breaks automatic builds. It causes rebuilds
for packages that depend on kernel for no real reason.

Further, quoting Michal, who removed most of the users already:
The kernel already prints its build timestamp during boot, no need to
repeat it in random drivers and produce different object files each
time.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBIFS: use __aligned() attribute

.. instead of __attribute__((aligned())).

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBIFS: improve scanning debug output

Include LEB number and offset in scanning debugging output.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBIFS: print PID in debug messages

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBIFS: always print full error reports

Even when we are emulating power cuts, otherwise it is difficult to investigate
failures during emulated power cuts testing.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBIFS: fix power cut emulation for mtdram

The power cut emulation did not work correctly because we corrupted more than
one max. I/O unit in the buffer and then wrote the entire buffer. This lead to
recovery errors because UBIFS complained about corrupted free space. And this
was easily reproducible on mtdram because max. write size is very small there
(64 bytes), and we could easily have a 1KiB buffer, corrupt 128 bytes there,
and then write the entire buffer.

The fix is to corrupt max. write size bytes at most, and write only up to the
last corrupted max. write size chunk, not the entire buffer.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBIFS: comply with coding style

Join all the split printk lines in order to stop checkpatch complaining.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBIFS: use pr_ helper instead of printk

Use 'pr_err()' instead of 'printk(KERN_ERR', etc.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBIFS: print less

UBIFS currently prints a lot of information when it mounts a volume, which
bothers some people. Make it less chatty - print only important information
by default.

Get rid of 'dbg_msg()' macro completely.

Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBIFS: make space fixup work in the remount case

The UBIFS space fixup is a useful feature which allows to fixup the "broken"
flash space at the time of the first mount. The "broken" space is usually the
result of using a "dumb" industrial flasher which is not able to skip empty
NAND pages and just writes all 0xFFs to the empty space, which has grave
side-effects for UBIFS when UBIFS trise to write useful data to those empty
pages.

The fix-up feature works roughly like this:
1. mkfs.ubifs sets the fixup flag in UBIFS superblock when creating the image
   (see -F option)
2. when the file-system is mounted for the first time, UBIFS notices the fixup
   flag and re-writes the entire media atomically, which may take really a lot
   of time.
3. UBIFS clears the fixup flag in the superblock.

This works fine when the file system is mounted R/W for the very first time.
But it did not really work in the case when we first mount the file-system R/O,
and then re-mount R/W. The reason was that we started the fixup procedure too
late, which we cannot really do because we have to fixup the space before it
starts being used.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Reported-by: Mark Jackson <mpfj-list@mimc.co.uk>
Cc: stable@vger.kernel.org # 3.0+
UBIFS: correct mount message

When mounting an UBIFS R/W volume, we have the message:
UBIFS: mounted UBI device 0, volume 1, name "rootfs"(null)
With this patch, we'll have:
UBIFS: mounted UBI device 0, volume 1, name "rootfs"
Which is, I think, what was intended.

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Cc: stable@vger.kernel.org [v3.7+]
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBIFS: prepare to fix a horrid bug

Al Viro pointed me to the fact that '->readdir()' and '->llseek()' have no
mutual exclusion, which means the 'ubifs_dir_llseek()' can be run while we are
in the middle of 'ubifs_readdir()'.

First of all, this means that 'file->private_data' can be freed while
'ubifs_readdir()' uses it.  But this particular patch does not fix the problem.
This patch is only a preparation, and the fix will follow next.

In this patch we make 'ubifs_readdir()' stop using 'file->f_pos' directly,
because 'file->f_pos' can be changed by '->llseek()' at any point. This may
lead 'ubifs_readdir()' to returning inconsistent data: directory entry names
may correspond to incorrect file positions.

So here we introduce a local variable 'pos', read 'file->f_pose' once at very
the beginning, and then stick to 'pos'. The result of this is that when
'ubifs_dir_llseek()' changes 'file->f_pos' while we are in the middle of
'ubifs_readdir()', the latter "wins".

Cc: stable@vger.kernel.org
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
UBIFS: fix a horrid bug

Al Viro pointed me to the fact that '->readdir()' and '->llseek()' have no
mutual exclusion, which means the 'ubifs_dir_llseek()' can be run while we are
in the middle of 'ubifs_readdir()'.

This means that 'file->private_data' can be freed while 'ubifs_readdir()' uses
it, and this is a very bad bug: not only 'ubifs_readdir()' can return garbage,
but this may corrupt memory and lead to all kinds of problems like crashes an
security holes.

This patch fixes the problem by using the 'file->f_version' field, which
'->llseek()' always unconditionally sets to zero. We set it to 1 in
'ubifs_readdir()' and whenever we detect that it became 0, we know there was a
seek and it is time to clear the state saved in 'file->private_data'.

I tested this patch by writing a user-space program which runds readdir and
seek in parallell. I could easily crash the kernel without these patches, but
could not crash it with these patches.

Cc: stable@vger.kernel.org
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Conflicts:
	fs/ubifs/dir.c
UBIFS: remove unnecessary code in ubifs_garbage_collect

In ubifs_garbage_collect,local variable "space_before" calculate twice. In
fact, at the beginning of the loop, there is no need to calculate this
variable. Calculate it before call "ubifs_garbage_collect_leb" is enough. This
patch just remove the unnecessary calculate code.

Signed-off-by: wang bo <wang.bo116@zte.com.cn>
Acked-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
UBIFS: fix return code

Fix to return -ENOMEM in the kmalloc() and d_make_root() error handling
case instead of 0, as done elsewhere in those functions.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>