There is normally only a handful of these active at any one time, but
putting them in a separate slab cache makes debugging memory
corruption problems easier.  Manish Katiyar also wanted this make it
easier to test memory failure scenarios in the jbd2 layer.

Cc: Manish Katiyar <mkatiyar@gmail.com>
Signed-off-by: NYongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

This patch adds trace_jbd2_drop_transaction and
trace_jbd2_update_superblock_end because there are similar tracepoints
in jbd and they are needed in jbd2 as well.
Reviewed-by: NLukas Czerner <lczerner@redhat.com>
Signed-off-by: NSeiji Aguchi <seiji.aguchi@hds.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

There is no reason to export two functions for entering the
refrigerator.  Calling refrigerator() instead of try_to_freeze()
doesn't save anything noticeable or removes any race condition.

* Rename refrigerator() to __refrigerator() and make it return bool
  indicating whether it scheduled out for freezing.

* Update try_to_freeze() to return bool and relay the return value of
  __refrigerator() if freezing().

* Convert all refrigerator() users to try_to_freeze().

* Update documentation accordingly.

* While at it, add might_sleep() to try_to_freeze().
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Samuel Ortiz <samuel@sortiz.org>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: Christoph Hellwig <hch@infradead.org>

Some jbd2 code prints out kernel messages with "JBD2: " prefix, at the
same time other jbd2 code prints with "JBD: " prefix. Unify the prefix
to "JBD2: ".
Signed-off-by: NEryu Guan <guaneryu@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

I hit a J_ASSERT(blocknr != 0) failure in cleanup_journal_tail() when
mounting a fsfuzzed ext3 image. It turns out that the corrupted ext3
image has s_first = 0 in journal superblock, and the 0 is passed to
journal->j_head in journal_reset(), then to blocknr in
cleanup_journal_tail(), in the end the J_ASSERT failed.

So validate s_first after reading journal superblock from disk in
journal_get_superblock() to ensure s_first is valid.

The following script could reproduce it:

fstype=ext3
blocksize=1024
img=$fstype.img
offset=0
found=0
magic="c0 3b 39 98"

dd if=/dev/zero of=$img bs=1M count=8
mkfs -t $fstype -b $blocksize -F $img
filesize=`stat -c %s $img`
while [ $offset -lt $filesize ]
do
        if od -j $offset -N 4 -t x1 $img | grep -i "$magic";then
                echo "Found journal: $offset"
                found=1
                break
        fi
        offset=`echo "$offset+$blocksize" | bc`
done

if [ $found -ne 1 ];then
        echo "Magic \"$magic\" not found"
        exit 1
fi

dd if=/dev/zero of=$img seek=$(($offset+23)) conv=notrunc bs=1 count=1

mkdir -p ./mnt
mount -o loop $img ./mnt

Cc: Jan Kara <jack@suse.cz>
Signed-off-by: NEryu Guan <guaneryu@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Using function calls in TP_printk causes perf heartburn, so print the
MAJOR/MINOR device numbers instead.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

jbd2_journal_remove_journal_head() can oops when trying to access
journal_head returned by bh2jh(). This is caused for example by the
following race:

	TASK1					TASK2
  jbd2_journal_commit_transaction()
    ...
    processing t_forget list
      __jbd2_journal_refile_buffer(jh);
      if (!jh->b_transaction) {
        jbd_unlock_bh_state(bh);
					jbd2_journal_try_to_free_buffers()
					  jbd2_journal_grab_journal_head(bh)
					  jbd_lock_bh_state(bh)
					  __journal_try_to_free_buffer()
					  jbd2_journal_put_journal_head(jh)
        jbd2_journal_remove_journal_head(bh);

jbd2_journal_put_journal_head() in TASK2 sees that b_jcount == 0 and
buffer is not part of any transaction and thus frees journal_head
before TASK1 gets to doing so. Note that even buffer_head can be
released by try_to_free_buffers() after
jbd2_journal_put_journal_head() which adds even larger opportunity for
oops (but I didn't see this happen in reality).

Fix the problem by making transactions hold their own journal_head
reference (in b_jcount). That way we don't have to remove journal_head
explicitely via jbd2_journal_remove_journal_head() and instead just
remove journal_head when b_jcount drops to zero. The result of this is
that [__]jbd2_journal_refile_buffer(),
[__]jbd2_journal_unfile_buffer(), and
__jdb2_journal_remove_checkpoint() can free journal_head which needs
modification of a few callers. Also we have to be careful because once
journal_head is removed, buffer_head might be freed as well. So we
have to get our own buffer_head reference where it matters.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Provide a function which returns whether a transaction with given tid
will send a flush to the filesystem device.  The function will be used
by ext4 to detect whether fsync needs to send a separate flush or not.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

If we somehow wrap, we don't want to keep printing the warning message
over and over again.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

If an application program does not make any changes to the indirect
blocks or extent tree, i_datasync_tid will not get updated.  If there
are enough commits (i.e., 2**31) such that tid_geq()'s calculations
wrap, and there isn't a currently active transaction at the time of
the fdatasync() call, this can end up triggering a BUG_ON in
fs/jbd2/commit.c:

	J_ASSERT(journal->j_running_transaction != NULL);

It's pretty rare that this can happen, since it requires the use of
fdatasync() plus *very* frequent and excessive use of fsync().  But
with the right workload, it can.

We fix this by replacing the use of tid_geq() with an equality test,
since there's only one valid transaction id that we is valid for us to
wait until it is commited: namely, the currently running transaction
(if it exists).
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

bdget() should not be called when we hold spinlocks since
it might sleep.
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NZhu Yanhai <gaoyang.zyh@taobao.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>

The Patch below removes one to many "n's" in a word..
Signed-off-by: NJustin P. Mattock <justinmattock@gmail.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: linux-ext4@vger.kernel.org
Acked-by: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NJan Kara <jack@suse.cz>

On an SMP ARM system running ext4, I've received a report that the
first J_ASSERT in jbd2_journal_commit_transaction has been triggering:

	J_ASSERT(journal->j_running_transaction != NULL);

While investigating possible causes for this problem, I noticed that
__jbd2_log_start_commit() is getting called with j_state_lock only
read-locked, in spite of the fact that it's possible for it might
j_commit_request.  Fix this by grabbing the necessary information so
we can test to see if we need to start a new transaction before
dropping the read lock, and then calling jbd2_log_start_commit() which
will grab the write lock.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Replace the jbd2_inode structure (which is 48 bytes) with a pointer
and only allocate the jbd2_inode when it is needed --- that is, when
the file system has a journal present and the inode has been opened
for writing.  This allows us to further slim down the ext4_inode_info
structure.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

We had an open-coded version of printk_ratelimited(); use the provided
abstraction to make the code cleaner and easier to understand.

Based on a similar patch for fs/jbd from Namhyung Kim <namhyung@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

In jbd2_journal_init_dev(), we need make sure the journal structure is
fully initialzied before calling jbd2_stats_proc_init().
Reviewed-by: NAndreas Dilger <andreas.dilger@oracle.com>
Signed-off-by: Nyangsheng <sheng.yang@oracle.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

jbd2_slab_create_sem is used as a mutex, so make it one.

[ akpm muttered: We may as well make it local to
jbd2_journal_create_slab() also. ]
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <alpine.LFD.2.00.1010162231480.2496@localhost6.localdomain6>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

This fixes a hang seen in jbd2_journal_release_jbd_inode
on a lot of Power 6 systems running with ext4. When we get
in the hung state, all I/O to the disk in question gets blocked
where we stay indefinitely. Looking at the task list, I can see
we are stuck in jbd2_journal_release_jbd_inode waiting on a
wake up. I added some debug code to detect this scenario and
dump additional data if we were stuck in jbd2_journal_release_jbd_inode
for longer than 30 minutes. When it hit, I was able to see that
i_flags was 0, suggesting we missed the wake up.

This patch changes i_flags to be an unsigned long, uses bit operators
to access it, and adds barriers around the accesses. Prior to applying
this patch, we were regularly hitting this hang on numerous systems
in our test environment. After applying the patch, the hangs no longer
occur.
Signed-off-by: NBrian King <brking@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

"wakup"
Signed-off-by: NAndrea Gelmini <andrea.gelmini@gelma.net>
Signed-off-by: NJan Kara <jack@suse.cz>

Before we start accessing a huge (> 16 TiB) OCFS2 volume, we need to
confirm that its journal supports 64-bit offsets.  In particular, we
need to check the journal's feature bits before recovering the journal.

This is not possible with JBD2 at present, because the journal
superblock (where the feature bits reside) is not loaded from disk until
the journal is recovered.

This patch loads the journal superblock in
jbd2_journal_check_used_features() if it has not already been loaded,
allowing us to check the feature bits before journal recovery.
Signed-off-by: NPatrick LoPresti <lopresti@gmail.com>
Cc: linux-ext4@vger.kernel.org
Acked-by: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

These flags aren't real I/O types, but tell ll_rw_block to always
lock the buffer instead of giving up on a failed trylock.

Instead add a new write_dirty_buffer helper that implements this semantic
and use it from the existing SWRITE* callers.  Note that the ll_rw_block
code had a bug where it didn't promote WRITE_SYNC_PLUG properly, which
this patch fixes.

In the ufs code clean up the helper that used to call ll_rw_block
to mirror sync_dirty_buffer, which is the function it implements for
compound buffers.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Lockstat reports have shown that j_state_lock is a major source of
lock contention, especially on systems with more than 4 CPU cores.  So
change it to be a read/write spinlock.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

__GFP_NOFAIL is going away, so add our own retry loop.  Also add
jbd2__journal_start() and jbd2__journal_restart() which take a gfp
mask, so that file systems can optionally (re)start transaction
handles using GFP_KERNEL.  If they do this, then they need to be
prepared to handle receiving an PTR_ERR(-ENOMEM) error, and be ready
to reflect that error up to userspace.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

OCFS2 uses t_commit trigger to compute and store checksum of the just
committed blocks. When a buffer has b_frozen_data, checksum is computed
for it instead of b_data but this can result in an old checksum being
written to the filesystem in the following scenario:

1) transaction1 is opened
2) handle1 is opened
3) journal_access(handle1, bh)
    - This sets jh->b_transaction to transaction1
4) modify(bh)
5) journal_dirty(handle1, bh)
6) handle1 is closed
7) start committing transaction1, opening transaction2
8) handle2 is opened
9) journal_access(handle2, bh)
    - This copies off b_frozen_data to make it safe for transaction1 to commit.
      jh->b_next_transaction is set to transaction2.
10) jbd2_journal_write_metadata() checksums b_frozen_data
11) the journal correctly writes b_frozen_data to the disk journal
12) handle2 is closed
    - There was no dirty call for the bh on handle2, so it is never queued for
      any more journal operation
13) Checkpointing finally happens, and it just spools the bh via normal buffer
writeback.  This will write b_data, which was never triggered on and thus
contains a wrong (old) checksum.

This patch fixes the problem by calling the trigger at the moment data is
frozen for journal commit - i.e., either when b_frozen_data is created by
do_get_write_access or just before we write a buffer to the log if
b_frozen_data does not exist. We also rename the trigger to t_frozen as
that better describes when it is called.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NMark Fasheh <mfasheh@suse.com>
Signed-off-by: NJoel Becker <joel.becker@oracle.com>

No real bugs found, just removed some dead code.

Found by gcc 4.6's new warnings.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Fixes sparse warning:

fs/jbd2/journal.c:1892:9: warning: Using plain integer as NULL pointer
Signed-off-by: NBill Pemberton <wfp5p@virginia.edu>
CC: linux-ext4@vger.kernel.org
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

It triggers the warning in get_page_from_freelist(), and it isn't
appropriate to use __GFP_NOFAIL here anyway.

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=14843Reported-by: NChristian Casteyde <casteyde.christian@free.fr>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

jbd-debug and jbd2-debug is currently read-only (S_IRUGO), which is not
correct. Make it writable so that we can start debuging.
Signed-off-by: NYin Kangkai <kangkai.yin@intel.com>
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJan Kara <jack@suse.cz>

    
    This fixes:
    ERROR: "jbd2_log_start_commit" [fs/ext4/ext4.ko] undefined!
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Now that the SLUB seems to be fixed so that it respects the requested
alignment, use kmem_cache_alloc() to allocator if the block size of
the buffer heads to be allocated is less than the page size.
Previously, we were using 16k page on a Power system for each buffer,
even when the file system was using 1k or 4k block size.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

OOM happens.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

If there is a failed journal checksum, don't reset the journal.  This
allows for userspace programs to decide how to recover from this
situation.  It may be that ignoring the journal checksum failure might
be a better way of recovering the file system.  Once we add per-block
checksums, we can definitely do better.  Until then, a system
administrator can try backing up the file system image (or taking a
snapshot) and and trying to determine experimentally whether ignoring
the checksum failure or aborting the journal replay results in less
data loss.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org

If journal init fails, we need to free j_wbuf.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: NTao Ma <tao.ma@oracle.com>
Signed-off-by: NJan Kara <jack@suse.cz>

[akpm@linux-foundation.org: fix KVM]
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Acked-by: NMike Frysinger <vapier@gentoo.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The /proc/fs/jbd2/<dev>/history was maintained manually; by using
tracepoints, we can get all of the existing functionality of the /proc
file plus extra capabilities thanks to the ftrace infrastructure.  We
save memory as a bonus.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

There are a number of kernel printk's which are printed when an ext4
filesystem is mounted and unmounted.  Disable them to economize space
in the system logs.  In addition, disabling the mballoc stats by
default saves a number of unneeded atomic operations for every block
allocation or deallocation.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Make all seq_operations structs const, to help mitigate against
revectoring user-triggerable function pointers.

This is derived from the grsecurity patch, although generated from scratch
because it's simpler than extracting the changes from there.
Signed-off-by: NJames Morris <jmorris@namei.org>
Acked-by: NSerge Hallyn <serue@us.ibm.com>
Acked-by: NCasey Schaufler <casey@schaufler-ca.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The function jbd2_journal_write_metadata_buffer() calls
jbd_unlock_bh_state(bh_in) too early; this could potentially allow
another thread to call get_write_access on the buffer head, modify the
data, and dirty it, and allowing the wrong data to be written into the
journal.  Fortunately, if we lose this race, the only time this will
actually cause filesystem corruption is if there is a system crash or
other unclean shutdown of the system before the next commit can take
place.
Signed-off-by: Ndingdinghua <dingdinghua85@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>