This adds a new field in ext4_group_info to cache the largest available
block range in a block group; and don't load the buddy pages until *after*
we've done a sanity check on the block group.

With large allocation requests (e.g., fallocate(), 8MiB) and relatively full
partitions, it's easy to have no block groups with a block extent large
enough to satisfy the input request length.  This currently causes the loop
during cr == 0 in ext4_mb_regular_allocator() to load the buddy bitmap pages
for EVERY block group.  That can be a lot of pages.  The patch below allows
us to call ext4_mb_good_group() BEFORE we load the buddy pages (although we
have check again after we lock the block group).

Addresses-Google-Bug: #2578108
Addresses-Google-Bug: #2704453
Signed-off-by: NCurt Wohlgemuth <curtw@google.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Turn off issuance of discard requests if the device does
not support it - similar to the action we take for barriers.
This will save a little computation time if a non-discardable
device is mounted with -o discard, and also makes it obvious
that it's not doing what was asked at mount time ...
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

This function cleans up after ext4_mb_load_buddy(), so the renaming
makes the code clearer.
Signed-off-by: NJing Zhang <zj.barak@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Signed-off-by: NJing Zhang <zj.barak@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Otherwise, we can end up having data corruption because the blocks
could get reused and then discarded!

https://bugzilla.kernel.org/show_bug.cgi?id=15579Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

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>

ext4 uses rb_node = NULL; to zero rb_root at few places.  Using
RB_ROOT as the initializer is more portable in case the underlying
implementation of rbtrees changes in the future.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: Eric Paris <eparis@redhat.com>

Get rid of the alloc_space, free_space, reserve_space, claim_space and
release_rsv dquot operations - they are always called from the filesystem
and if a filesystem really needs their own (which none currently does)
it can just call into it's own routine directly.

Move shared logic into the common __dquot_alloc_space,
dquot_claim_space_nodirty and __dquot_free_space low-level methods,
and rationalize the wrappers around it to move as much as possible
code into the common block for CONFIG_QUOTA vs not.  Also rename
all these helpers to be named dquot_* instead of vfs_dq_*.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

More cleanup to convert open-coded calculations of the first block
number of a free extent to use ext4_grp_offs_to_block() instead.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger@sun.com>

This is a cleanup and simplification patch which takes some open-coded
calculations to calculate the first block number of a group and
converts them to use the (already defined) ext4_group_first_block_no()
function.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger@sun.com>

The ext4 multiblock allocator decides whether to use group or file
preallocation based on the file size.  When the file size reaches
s_mb_stream_request (default is 16 blocks), it changes to use a
file-specific preallocation. This is cool, but it has a tiny problem.

See a simple script:
mkfs.ext4 -b 1024 /dev/sda8 1000000
mount -t ext4 -o nodelalloc /dev/sda8 /mnt/ext4
for((i=0;i<5;i++))
do
cat /mnt/4096>>/mnt/ext4/a	#4096 is a file with 4096 characters.
cat /mnt/4096>>/mnt/ext4/b
done
debuge4fs -R 'stat a' /dev/sda8|grep BLOCKS -A 1

And you get
BLOCKS:
(0-14):8705-8719, (15):2356, (16-19):8465-8468

So there are 3 extents, a bit strange for the lonely 15th logical
block.  As we write to the 16 blocks, we choose file preallocation in
ext4_mb_group_or_file, but in ext4_mb_normalize_request, we meet with
the 16*1024 range, so no preallocation will be carried. file b then
reserves the space after '2356', so when when write 16, we start from
another part.

This patch just change the check in ext4_mb_group_or_file, so
that for the lonely 15 we will still use group preallocation.
After the patch, we will get:
debuge4fs -R 'stat a' /dev/sda8|grep BLOCKS -A 1
BLOCKS:
(0-15):8705-8720, (16-19):8465-8468

Looks more sane. Thanks.
Signed-off-by: NTao Ma <tao.ma@oracle.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>

Some misspelled occurences of 'octet' and some comments were also fixed
as I was on it.
Signed-off-by: NDaniel Mack <daniel@caiaq.de>
Cc: Jiri Kosina <trivial@kernel.org>
Cc: Joe Perches <joe@perches.com>
Cc: Junio C Hamano <gitster@pobox.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

We have to delay vfs_dq_claim_space() until allocation context destruction.
Currently we have following call-trace:
ext4_mb_new_blocks()
  /* task is already holding ac->alloc_semp */
 ->ext4_mb_mark_diskspace_used
    ->vfs_dq_claim_space()  /*  acquire dqptr_sem here. Possible deadlock */
 ->ext4_mb_release_context() /* drop ac->alloc_semp here */

Let's move quota claiming to ext4_da_update_reserve_space()

 =======================================================
 [ INFO: possible circular locking dependency detected ]
 2.6.32-rc7 #18
 -------------------------------------------------------
 write-truncate-/3465 is trying to acquire lock:
  (&s->s_dquot.dqptr_sem){++++..}, at: [<c025e73b>] dquot_claim_space+0x3b/0x1b0

 but task is already holding lock:
  (&meta_group_info[i]->alloc_sem){++++..}, at: [<c02ce962>] ext4_mb_load_buddy+0xb2/0x370

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #3 (&meta_group_info[i]->alloc_sem){++++..}:
        [<c017d04b>] __lock_acquire+0xd7b/0x1260
        [<c017d5ea>] lock_acquire+0xba/0xd0
        [<c0527191>] down_read+0x51/0x90
        [<c02ce962>] ext4_mb_load_buddy+0xb2/0x370
        [<c02d0c1c>] ext4_mb_free_blocks+0x46c/0x870
        [<c029c9d3>] ext4_free_blocks+0x73/0x130
        [<c02c8cfc>] ext4_ext_truncate+0x76c/0x8d0
        [<c02a8087>] ext4_truncate+0x187/0x5e0
        [<c01e0f7b>] vmtruncate+0x6b/0x70
        [<c022ec02>] inode_setattr+0x62/0x190
        [<c02a2d7a>] ext4_setattr+0x25a/0x370
        [<c022ee81>] notify_change+0x151/0x340
        [<c021349d>] do_truncate+0x6d/0xa0
        [<c0221034>] may_open+0x1d4/0x200
        [<c022412b>] do_filp_open+0x1eb/0x910
        [<c021244d>] do_sys_open+0x6d/0x140
        [<c021258e>] sys_open+0x2e/0x40
        [<c0103100>] sysenter_do_call+0x12/0x32

 -> #2 (&ei->i_data_sem){++++..}:
        [<c017d04b>] __lock_acquire+0xd7b/0x1260
        [<c017d5ea>] lock_acquire+0xba/0xd0
        [<c0527191>] down_read+0x51/0x90
        [<c02a5787>] ext4_get_blocks+0x47/0x450
        [<c02a74c1>] ext4_getblk+0x61/0x1d0
        [<c02a7a7f>] ext4_bread+0x1f/0xa0
        [<c02bcddc>] ext4_quota_write+0x12c/0x310
        [<c0262d23>] qtree_write_dquot+0x93/0x120
        [<c0261708>] v2_write_dquot+0x28/0x30
        [<c025d3fb>] dquot_commit+0xab/0xf0
        [<c02be977>] ext4_write_dquot+0x77/0x90
        [<c02be9bf>] ext4_mark_dquot_dirty+0x2f/0x50
        [<c025e321>] dquot_alloc_inode+0x101/0x180
        [<c029fec2>] ext4_new_inode+0x602/0xf00
        [<c02ad789>] ext4_create+0x89/0x150
        [<c0221ff2>] vfs_create+0xa2/0xc0
        [<c02246e7>] do_filp_open+0x7a7/0x910
        [<c021244d>] do_sys_open+0x6d/0x140
        [<c021258e>] sys_open+0x2e/0x40
        [<c0103100>] sysenter_do_call+0x12/0x32

 -> #1 (&sb->s_type->i_mutex_key#7/4){+.+...}:
        [<c017d04b>] __lock_acquire+0xd7b/0x1260
        [<c017d5ea>] lock_acquire+0xba/0xd0
        [<c0526505>] mutex_lock_nested+0x65/0x2d0
        [<c0260c9d>] vfs_load_quota_inode+0x4bd/0x5a0
        [<c02610af>] vfs_quota_on_path+0x5f/0x70
        [<c02bc812>] ext4_quota_on+0x112/0x190
        [<c026345a>] sys_quotactl+0x44a/0x8a0
        [<c0103100>] sysenter_do_call+0x12/0x32

 -> #0 (&s->s_dquot.dqptr_sem){++++..}:
        [<c017d361>] __lock_acquire+0x1091/0x1260
        [<c017d5ea>] lock_acquire+0xba/0xd0
        [<c0527191>] down_read+0x51/0x90
        [<c025e73b>] dquot_claim_space+0x3b/0x1b0
        [<c02cb95f>] ext4_mb_mark_diskspace_used+0x36f/0x380
        [<c02d210a>] ext4_mb_new_blocks+0x34a/0x530
        [<c02c83fb>] ext4_ext_get_blocks+0x122b/0x13c0
        [<c02a5966>] ext4_get_blocks+0x226/0x450
        [<c02a5ff3>] mpage_da_map_blocks+0xc3/0xaa0
        [<c02a6ed6>] ext4_da_writepages+0x506/0x790
        [<c01de272>] do_writepages+0x22/0x50
        [<c01d766d>] __filemap_fdatawrite_range+0x6d/0x80
        [<c01d7b9b>] filemap_flush+0x2b/0x30
        [<c02a40ac>] ext4_alloc_da_blocks+0x5c/0x60
        [<c029e595>] ext4_release_file+0x75/0xb0
        [<c0216b59>] __fput+0xf9/0x210
        [<c0216c97>] fput+0x27/0x30
        [<c02122dc>] filp_close+0x4c/0x80
        [<c014510e>] put_files_struct+0x6e/0xd0
        [<c01451b7>] exit_files+0x47/0x60
        [<c0146a24>] do_exit+0x144/0x710
        [<c0147028>] do_group_exit+0x38/0xa0
        [<c0159abc>] get_signal_to_deliver+0x2ac/0x410
        [<c0102849>] do_notify_resume+0xb9/0x890
        [<c01032d2>] work_notifysig+0x13/0x21

 other info that might help us debug this:

 3 locks held by write-truncate-/3465:
  #0:  (jbd2_handle){+.+...}, at: [<c02e1f8f>] start_this_handle+0x38f/0x5c0
  #1:  (&ei->i_data_sem){++++..}, at: [<c02a57f6>] ext4_get_blocks+0xb6/0x450
  #2:  (&meta_group_info[i]->alloc_sem){++++..}, at: [<c02ce962>] ext4_mb_load_buddy+0xb2/0x370

 stack backtrace:
 Pid: 3465, comm: write-truncate- Not tainted 2.6.32-rc7 #18
 Call Trace:
  [<c0524cb3>] ? printk+0x1d/0x22
  [<c017ac9a>] print_circular_bug+0xca/0xd0
  [<c017d361>] __lock_acquire+0x1091/0x1260
  [<c016bca2>] ? sched_clock_local+0xd2/0x170
  [<c0178fd0>] ? trace_hardirqs_off_caller+0x20/0xd0
  [<c017d5ea>] lock_acquire+0xba/0xd0
  [<c025e73b>] ? dquot_claim_space+0x3b/0x1b0
  [<c0527191>] down_read+0x51/0x90
  [<c025e73b>] ? dquot_claim_space+0x3b/0x1b0
  [<c025e73b>] dquot_claim_space+0x3b/0x1b0
  [<c02cb95f>] ext4_mb_mark_diskspace_used+0x36f/0x380
  [<c02d210a>] ext4_mb_new_blocks+0x34a/0x530
  [<c02c601d>] ? ext4_ext_find_extent+0x25d/0x280
  [<c02c83fb>] ext4_ext_get_blocks+0x122b/0x13c0
  [<c016bca2>] ? sched_clock_local+0xd2/0x170
  [<c016be60>] ? sched_clock_cpu+0x120/0x160
  [<c016beef>] ? cpu_clock+0x4f/0x60
  [<c0178fd0>] ? trace_hardirqs_off_caller+0x20/0xd0
  [<c052712c>] ? down_write+0x8c/0xa0
  [<c02a5966>] ext4_get_blocks+0x226/0x450
  [<c016be60>] ? sched_clock_cpu+0x120/0x160
  [<c016beef>] ? cpu_clock+0x4f/0x60
  [<c017908b>] ? trace_hardirqs_off+0xb/0x10
  [<c02a5ff3>] mpage_da_map_blocks+0xc3/0xaa0
  [<c01d69cc>] ? find_get_pages_tag+0x16c/0x180
  [<c01d6860>] ? find_get_pages_tag+0x0/0x180
  [<c02a73bd>] ? __mpage_da_writepage+0x16d/0x1a0
  [<c01dfc4e>] ? pagevec_lookup_tag+0x2e/0x40
  [<c01ddf1b>] ? write_cache_pages+0xdb/0x3d0
  [<c02a7250>] ? __mpage_da_writepage+0x0/0x1a0
  [<c02a6ed6>] ext4_da_writepages+0x506/0x790
  [<c016beef>] ? cpu_clock+0x4f/0x60
  [<c016bca2>] ? sched_clock_local+0xd2/0x170
  [<c016be60>] ? sched_clock_cpu+0x120/0x160
  [<c016be60>] ? sched_clock_cpu+0x120/0x160
  [<c02a69d0>] ? ext4_da_writepages+0x0/0x790
  [<c01de272>] do_writepages+0x22/0x50
  [<c01d766d>] __filemap_fdatawrite_range+0x6d/0x80
  [<c01d7b9b>] filemap_flush+0x2b/0x30
  [<c02a40ac>] ext4_alloc_da_blocks+0x5c/0x60
  [<c029e595>] ext4_release_file+0x75/0xb0
  [<c0216b59>] __fput+0xf9/0x210
  [<c0216c97>] fput+0x27/0x30
  [<c02122dc>] filp_close+0x4c/0x80
  [<c014510e>] put_files_struct+0x6e/0xd0
  [<c01451b7>] exit_files+0x47/0x60
  [<c0146a24>] do_exit+0x144/0x710
  [<c017b163>] ? lock_release_holdtime+0x33/0x210
  [<c0528137>] ? _spin_unlock_irq+0x27/0x30
  [<c0147028>] do_group_exit+0x38/0xa0
  [<c017babb>] ? trace_hardirqs_on+0xb/0x10
  [<c0159abc>] get_signal_to_deliver+0x2ac/0x410
  [<c0102849>] do_notify_resume+0xb9/0x890
  [<c0178fd0>] ? trace_hardirqs_off_caller+0x20/0xd0
  [<c017b163>] ? lock_release_holdtime+0x33/0x210
  [<c0165b50>] ? autoremove_wake_function+0x0/0x50
  [<c017ba54>] ? trace_hardirqs_on_caller+0x134/0x190
  [<c017babb>] ? trace_hardirqs_on+0xb/0x10
  [<c0300ba4>] ? security_file_permission+0x14/0x20
  [<c0215761>] ? vfs_write+0x131/0x190
  [<c0214f50>] ? do_sync_write+0x0/0x120
  [<c0103115>] ? sysenter_do_call+0x27/0x32
  [<c01032d2>] work_notifysig+0x13/0x21

CC: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: NDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NJan Kara <jack@suse.cz>

Add checks to ext4_free_branches() to make sure a block number found
in an indirect block are valid before trying to free it.  If a bad
block number is found, stop freeing the indirect block immediately,
since the file system is corrupt and we will need to run fsck anyway.
This also avoids spamming the logs, and specifically avoids
driver-level "attempt to access beyond end of device" errors obscure
what is really going on.

If you get *really*, *really*, *really* unlucky, without this patch, a
supposed indirect block containing garbage might contain a reference
to a primary block group descriptor, in which case
ext4_free_branches() could end up zero'ing out a block group
descriptor block, and if then one of the block bitmaps for a block
group described by that bg descriptor block is not in memory, and is
read in by ext4_read_block_bitmap().  This function calls
ext4_valid_block_bitmap(), which assumes that bg_inode_table() was
validated at mount time and hasn't been modified since.  Since this
assumption is no longer valid, it's possible for the value
(ext4_inode_table(sb, desc) - group_first_block) to go negative, which
will cause ext4_find_next_zero_bit() to trigger a kernel GPF.

Addresses-Google-Bug: #2220436
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

This fixes a leak of blocks in an inode prealloc list if device failures
cause ext4_mb_mark_diskspace_used() to fail.
Signed-off-by: NCurt Wohlgemuth <curtw@google.com>
Acked-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

That is "success", "unknown", "through", "performance", "[re|un]mapping"
, "access", "default", "reasonable", "[con]currently", "temperature"
, "channel", "[un]used", "application", "example","hierarchy", "therefore"
, "[over|under]flow", "contiguous", "threshold", "enough" and others.
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

The block validity framework does a more comprehensive set of checks,
and it saves object code space to use the ext4_data_block_valid() than
the limited open-coded version that had been in ext4_free_blocks().
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Add the facility for ext4_forget() to be called from
ext4_free_blocks().  This simplifies the code in a large number of
places, and centralizes most of the work of calling ext4_forget() into
a single place.

Also fix a bug in the extents migration code; it wasn't calling
ext4_forget() when releasing the indirect blocks during the
conversion.  As a result, if the system cashed during or shortly after
the extents migration, and the released indirect blocks get reused as
data blocks, the journal replay would corrupt the data blocks.  With
this new patch, fixing this bug was as simple as adding the
EXT4_FREE_BLOCKS_FORGET flags to the call to ext4_free_blocks().
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>

ext4_mb_free_blocks() is only called by ext4_free_blocks(), and the
latter function doesn't really do much.  So merge the two functions
together, such that ext4_free_blocks() is now found in
fs/ext4/mballoc.c.  This saves about 200 bytes of compiled text space.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

It is anticipated that when sb_issue_discard starts doing
real work on trim-capable devices, we may see issues.  Make
this mount-time optional, and default it to off until we know
that things are working out OK.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Use this_cpu_ptr and __this_cpu_ptr in locations where straight
transformations are possible because per_cpu_ptr is used with
either smp_processor_id() or raw_smp_processor_id().

cc: David Howells <dhowells@redhat.com>
Acked-by: NTejun Heo <tj@kernel.org>
cc: Ingo Molnar <mingo@elte.hu>
cc: Rusty Russell <rusty@rustcorp.com.au>
cc: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: NChristoph Lameter <cl@linux-foundation.org>
Signed-off-by: NTejun Heo <tj@kernel.org>

The /proc/fs/ext4/<dev>/mb_history was maintained manually, and had a
number of problems: it required a largish amount of memory to be
allocated for each ext4 filesystem, and the s_mb_history_lock
introduced a CPU contention problem.  

By ripping out the mb_history code and replacing it with ftrace
tracepoints, and we get more functionality: timestamps, event
filtering, the ability to correlate mballoc history with other ext4
tracepoints, etc.
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>

The hueristic was designed to avoid using locality group preallocation
when writing the last segment of a closed file.  Fix it by move
setting size to the maximum of size and isize until after we check
whether size == isize.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Today, the ext4 allocator will happily allocate blocks past
2^32 for indirect-block files, which results in the block
numbers getting truncated, and corruption ensues.

This patch limits such allocations to < 2^32, and adds
BUG_ONs if we do get blocks larger than that.

This should address RH Bug 519471, ext4 bitmap allocator 
must limit blocks to < 2^32

* ext4_find_goal() is modified to choose a goal < UINT_MAX,
  so that our starting point is in an acceptable range.

* ext4_xattr_block_set() is modified such that the goal block
  is < UINT_MAX, as above.

* ext4_mb_regular_allocator() is modified so that the group
  search does not continue into groups which are too high

* ext4_mb_use_preallocated() has a check that we don't use
  preallocated space which is too far out

* ext4_alloc_blocks() and ext4_xattr_block_set() add some BUG_ONs

No attempt has been made to limit inode locations to < 2^32,
so we may wind up with blocks far from their inodes.  Doing
this much already will lead to some odd ENOSPC issues when the
"lower 32" gets full, and further restricting inodes could
make that even weirder.

For high inodes, choosing a goal of the original, % UINT_MAX,
may be a bit odd, but then we're in an odd situation anyway,
and I don't know of a better heuristic.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

We don't need to take the alloc_sem lock when we are adding new
groups, since mballoc won't see the new group added until we bump
sbi->s_groups_count.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

We should check for need init flag with the group's alloc_sem held, to
make sure while we are loading the buddy cache and holding a reference
to it, a file system resize can't add new blocks to same group.

The patch also drops the need init flag check in
ext4_mb_regular_allocator() because doing the check without holding
alloc_sem is racy.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

This moves the function around so that it can be called from
ext4_mb_load_buddy().
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

unsigned  short is potentially too small to track blocks within
a group; today it is safe due to restrictions in e2fsprogs but
we have _lo / _hi bits for group blocks with the intent to go
up to 32 bits, so clean this up now.

There are many more places where we use unsigned/int/unsigned int
to contain a group block but this should at least fix all the
short types.

I added a few comments to the struct ext4_group_info definition
as well.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Precursor to changing some types; to keep things in sync, it 
seems better to allocate/memset based on the size of the 
variables we are using rather than on some disconnected 
basic type like "unsigned short"
Signed-off-by: NEric Sandeen <sandeen@redhat.com>

While reading through some of the mballoc code it seems that a couple
spots in the size normalization function could be streamlined.

The test for non-overlapping PAs can be or'd for the start & end
conditions, and the tests for adjacent PAs can be else-if'd - 
it's essentially independently testing:

	if (A + B <= C)
		...
	if (A > C)
		...

These cannot both be true so it seems like the else-if might
be slightly more efficient and/or informative.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

ext4_mb_update_group_info is only called in one place, and it's
extremely simple.  There's no reason to have it in a separate function
in a separate file as far as I can tell, it just obfuscates what's
really going on.

Perhaps it was intended to keep the grp->bb_* manipulation local to
mballoc.c but we're already accessing other grp-> fields in balloc.c
directly so this seems ok.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Currently the group preallocation code tries to find a large (512)
free block from which to do per-cpu group allocation for small files.
The problem with this scheme is that it leaves the filesystem horribly
fragmented.  In the worst case, if the filesystem is unmounted and
remounted (after a system shutdown, for example) we forget the fact
that wee were using a particular (now-partially filled) 512 block
extent.  So the next time we try to allocate space for a small file,
we will find *another* completely free 512 block chunk to allocate
small files.  Given that there are 32,768 blocks in a block group,
after 64 iterations of "mount, write one 4k file in a directory,
unmount", the block group will have 64 files, each separated by 511
blocks, and the block group will no longer have any free 512
completely free chunks of blocks for group preallocation space.

So if we try to allocate blocks for a file that has been closed, such
that we know the final size of the file, and the filesystem is not
busy, avoid using group preallocation.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The logic around sbi->s_mb_last_group and sbi->s_mb_last_start was all
screwed up.  These fields were getting unconditionally all the time,
set even when stream allocation had not taken place, and if they were
being used when the file was smaller than s_mb_stream_request, which
is when the allocation should _not_ be doing stream allocation.

Fix this by determining whether or not we stream allocation should
take place once, in ext4_mb_group_or_file(), and setting a flag which
gets used in ext4_mb_regular_allocator() and ext4_mb_use_best_found().
This simplifies the code and assures that we are consistently using
(or not using) the stream allocation logic.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Displaying the flags in base 16 makes it easier to see which flags
have been set.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Allow mballoc debugging to be enabled at run-time instead of just at
compile time.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Pavel Roskin pointed out that kmemcheck indicated that
ext4_mb_store_history() was accessing uninitialized values of
ac->ac_tail and ac->ac_buddy leading to garbage in the mballoc
history.  Fix this by initializing the entire structure to all zeros
first.

Also, two fields were getting doubly initialized by the caller of
ext4_mb_initialize_context, so remove them for efficiency's sake.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

When MB_DEBUG is enabled, we get some compile warnings because
ext4_group_t is unsigned int.  This patch fixes them.

Signed-off-by Akira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>