Dan Roseberg has reported a problem with the MOVE_EXT ioctl.  If the
donor file is an append-only file, we should not allow the operation
to proceed, lest we end up overwriting the contents of an append-only
file.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: Dan Rosenberg <dan.j.rosenberg@gmail.com>

At several places we modify EXT4_I(inode)->i_flags without holding
i_mutex (ext4_do_update_inode, ...). These modifications are racy and
we can lose updates to i_flags. So convert handling of i_flags to use
bitops which are atomic.

https://bugzilla.kernel.org/show_bug.cgi?id=15792Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

EXT4_ERROR_INODE() tends to provide better error information and in a
more consistent format.  Some errors were not even identifying the inode
or directory which was corrupted, which made them not very useful.

Addresses-Google-Bug: #2507977
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Making sure ee_block is initialized to zero to prevent gcc from
kvetching.  It's harmless (although it's not obvious that it's
harmless) from code inspection:

fs/ext4/move_extent.c:478: warning: 'start_ext.ee_block' may be used
uninitialized in this function

Thanks to Stefan Richter for first bringing this to the attention of
linux-ext4@vger.kernel.org.
Signed-off-by: LiuQi <lingjiujianke@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

a) Fix sparse warning in ext4_ioctl()
b) Remove unneeded variable in mext_leaf_block()
c) Fix spelling typo in mext_check_arguments()
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

If EXT4_IOC_MOVE_EXT ioctl is called with NULL donor_fd, fget() in
ext4_ioctl() gets inappropriate file structure for donor; so we need
to do this check earlier, before calling double_down_write_data_sem().
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

If the leaf node has 2 extent space or fewer and EXT4_IOC_MOVE_EXT
ioctl is called with the file offset where after the 2nd extent
covers, mext_insert_across_blocks() always tries to insert extent into
the first extent.  As a result, the file gets corrupted because of
wrong extent order.  The patch fixes this problem.
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Just a pet peeve of mine; we had a mishash of calls with either __func__
or "function_name" and the latter tends to get out of sync.

I think it's easier to just hide the __func__ in a macro, and it'll
be consistent from then on.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

In particular, several occurances of funny versions of 'success',
'unknown', 'therefore', 'acknowledge', 'argument', 'achieve', 'address',
'beginning', 'desirable', 'separate' and 'necessary' are fixed.
Signed-off-by: NDaniel Mack <daniel@caiaq.de>
Cc: Joe Perches <joe@perches.com>
Cc: Junio C Hamano <gitster@pobox.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

This patch fixes three problems in the handling of the
EXT4_IOC_MOVE_EXT ioctl:

1. In current EXT4_IOC_MOVE_EXT, there are read access mode checks for
original and donor files, but they allow the illegal write access to
donor file, since donor file is overwritten by original file data.  To
fix this problem, change access mode checks of original (r->r/w) and
donor (r->w) files.

2.  Disallow the use of donor files that have a setuid or setgid bits.

3.  Call mnt_want_write() and mnt_drop_write() before and after
ext4_move_extents() calling to get write access to a mount.
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Integrate duplicate lines (acquire/release semaphore and invalidate
extent cache in move_extent_per_page()) into mext_replace_branches(),
to reduce source and object code size.
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The move_extent.moved_len is used to pass back the number of exchanged
blocks count to user space.  Currently the caller must clear this
field; but we spend more code space checking for this requirement than
simply zeroing the field ourselves, so let's just make life easier for
everyone all around.
Signed-off-by: NKazuya Mio <k-mio@sx.jp.nec.com>
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

At the beginning of ext4_move_extent(), we call
ext4_discard_preallocations() to discard inode PAs of orig and donor
inodes.  But in the following case, blocks can be double freed, so
move ext4_discard_preallocations() to the end of ext4_move_extents().

1. Discard inode PAs of orig and donor inodes with
   ext4_discard_preallocations() in ext4_move_extents().

   orig : [ DATA1 ]
   donor: [ DATA2 ]

2. While data blocks are exchanging between orig and donor inodes, new
   inode PAs is created to orig by other process's block allocation.
   (Since there are semaphore gaps in ext4_move_extents().)  And new
   inode PAs is used partially (2-1).

   2-1 Create new inode PAs to orig inode
   orig : [ DATA1 | used PA1 | free PA1 ]
   donor: [ DATA2 ]

3. Donor inode which has old orig inode's blocks is deleted after
   EXT4_IOC_MOVE_EXT finished (3-1, 3-2).  So the block bitmap
   corresponds to old orig inode's blocks are freed.

   3-1 After EXT4_IOC_MOVE_EXT finished
   orig : [ DATA2 |  free PA1 ]
   donor: [ DATA1 |  used PA1 ]

   3-2 Delete donor inode
   orig : [ DATA2 |  free PA1 ]
   donor: [ FREE SPACE(DATA1) | FREE SPACE(used PA1) ]

4. The double-free of blocks is occurred, when close() is called to
   orig inode.  Because ext4_discard_preallocations() for orig inode
   frees used PA1 and free PA1, though used PA1 is already freed in 3.

   4-1 Double-free of blocks is occurred
   orig : [ DATA2 |  FREE SPACE(free PA1) ]
   donor: [ FREE SPACE(DATA1) | DOUBLE FREE(used PA1) ]
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Fix a few spelling typos in move_extent.c
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.co.jp>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

If CONFIG_PROVE_LOCKING is enabled, the double_down_write_data_sem()
will trigger a false-positive warning of a recursive lock.  Since we
take i_data_sem for the two inodes ordered by their inode numbers,
this isn't a problem.  Use of down_write_nested() will notify the lock
dependency checker machinery that there is no problem here.

This problem was reported by Brian Rogers:

	http://marc.info/?l=linux-ext4&m=125115356928011&w=1Reported-by: NBrian Rogers <brian@xyzw.org>
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

ext4_move_extents() checks the logical block contiguousness
of original file with ext4_find_extent() and mext_next_extent().
Therefore the extent which ext4_ext_path structure indicates
must not be changed between above functions.

But in current implementation, there is no i_data_sem protection
between ext4_ext_find_extent() and mext_next_extent().  So the extent
which ext4_ext_path structure indicates may be overwritten by
delalloc.  As a result, ext4_move_extents() will exchange wrong blocks
between original and donor files.  I change the place where
acquire/release i_data_sem to solve this problem.

Moreover, I changed move_extent_per_page() to start transaction first,
and then acquire i_data_sem.  Without this change, there is a
possibility of the deadlock between mmap() and ext4_move_extents():

* NOTE: "A", "B" and "C" mean different processes

A-1: ext4_ext_move_extents() acquires i_data_sem of two inodes.

B:   do_page_fault() starts the transaction (T),
     and then tries to acquire i_data_sem.
     But process "A" is already holding it, so it is kept waiting.

C:   While "A" and "B" running, kjournald2 tries to commit transaction (T)
     but it is under updating, so kjournald2 waits for it.

A-2: Call ext4_journal_start with holding i_data_sem,
     but transaction (T) is locked.
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

If the EXT4_IOC_MOVE_EXT ioctl fails, the number of blocks that were
exchanged before the failure should be returned to the userspace
caller.  Unfortunately, currently if the block size is not the same as
the page size, the returned block count that is returned is the
page-aligned block count instead of the actual block count.  This
commit addresses this bug.
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Move the check to make sure the original and donor inodes are
different earlier, to avoid a potential deadlock by trying to lock the
same inode twice.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

When writing into an unitialized extent via direct I/O, and the direct
I/O doesn't exactly cover the unitialized extent, split the extent
into uninitialized and initialized extents before submitting the I/O.
This avoids needing to deal with an ENOSPC error in the end_io
callback that gets used for direct I/O.

When the IO is complete, the written extent will be marked as initialized.

Singed-Off-By: Mingming Cao <cmm@us.ibm.com> 
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

There's no reason to redefine the maximum allowable offset
in an extent-based file just for defrag; 
EXT_MAX_BLOCK already does this.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

If logical block offset of original file which is passed to
EXT4_IOC_MOVE_EXT is different from donor file's,
a calculation error occurs in ext4_calc_swap_extents(),
therefore wrong block is exchanged between original file and donor file.
As a result, we hit ext4_error() in check_block_validity().
To detect the logical offset difference in EXT4_IOC_MOVE_EXT,
add checks to mext_calc_swap_extents() and handle it as error,
since data exchange must be done between the same blocks in EXT4_IOC_MOVE_EXT.
Reported-by: NPeng Tao <bergwolf@gmail.com>
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

There is the possibility that path structure which is taken
by ext4_ext_find_extent() indicates null extents.
Because during data block exchanging in ext4_move_extents(),
constitution of an extent tree may be changed.
As a solution, the patch adds null extent check
to ext_get_path().
Reported-by: NPeng Tao <bergwolf@gmail.com>
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Replace BUG_ON calls with a call to ext4_error()
to print an error message if EXT4_IOC_MOVE_EXT failed
with some kind of reasons.  This will help to debug.
Ted pointed this out, thanks.
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Replace get_ext_path macro with an inline function,
since this macro looks like a function call but its arguments
get modified. Ted pointed this out, thanks.
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

This function means moving extents every page, so change its name from
move_exgtent_par_page().
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.co.jp>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The ext4_move_extents() functions checks with BUG_ON() whether the
exchanged blocks count accords with request blocks count.  But, if the
target range (orig_start + len) includes sparse block(s), 'moved_len'
(exchanged blocks count) does not agree with 'len' (request blocks
count), since sparse block is not counted in 'moved_len'.  This causes
us to hit the BUG_ON(), even though the function succeeded.
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The mext_check_arguments() function in move_extents.c has wrong
comparisons.  orig_start which is passed from user-space is block
unit, but i_size of inode is byte unit, therefore the checks do not
work fine.  This mis-check leads to the overflow of 'len' and then
hits BUG_ON() in ext4_move_extents().  The patch fixes this issue.
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Reviewed-by: NGreg Freemyer <greg.freemyer@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

move_extent_par_page calls a_ops->write_begin() to increase journal
handler's reference count. However, if either mext_replace_branches()
or ext4_get_block fails, the increased reference count isn't
decreased. This will cause a later attempt to umount of the fs to hang
forever. The patch addresses the issue by calling ext4_journal_stop()
if page is not NULL (which means a_ops->write_end() isn't invoked).
Signed-off-by: NPeng Tao <bergwolf@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The EXT4_IOC_MOVE_EXT exchanges the blocks between orig_fd and donor_fd,
and then write the file data of orig_fd to donor_fd.
ext4_mext_move_extent() is the main fucntion of ext4 online defrag,
and this patch includes all functions related to ext4 online defrag.
Signed-off-by: NAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: NTakashi Sato <t-sato@yk.jp.nec.com>
Signed-off-by: NKazuya Mio <k-mio@sx.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>