A number of ext4 source files were skipped due because their copyright
permission statements didn't match the expected text used by the
automated conversion utilities.  I've added SPDX tags for the rest.

While looking at some of these files, I've noticed that we have quite
a bit of variation on the licenses that were used --- in particular
some of the Red Hat licenses on the jbd2 files use a GPL2+ license,
and we have some files that have a LGPL-2.1 license (which was quite
surprising).

I've not attempted to do any license changes.  Even if it is perfectly
legal to relicense to GPL 2.0-only for consistency's sake, that should
be done with ext4 developer community discussion.
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: NKate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: NPhilippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Now, when we mount ext4 filesystem with '-o discard' option, we have to
issue all the discard commands for the blocks to be deallocated and
wait for the completion of the commands on the commit complete phase.
Because this procedure might involve a lot of sequential combinations of
issuing discard commands and waiting for that, the delay of this
procedure might be too much long, even to 17.0s in our test,
and it results in long commit delay and fsync() performance degradation.

To reduce this kind of delay, instead of adding callback for each
extent and handling all of them in a sequential manner on commit phase,
we instead add a separate list of extents to free to the superblock and
then process this list at once after transaction commits so that
we can issue all the discard commands in a parallel manner like XFS
filesystem.

Finally, we could enhance the discard command handling performance.
The result was such that 17.0s delay of a single commit in the worst
case has been enhanced to 4.8s.
Signed-off-by: NDaeho Jeong <daeho.jeong@samsung.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Tested-by: NHobin Woo <hobin.woo@samsung.com>
Tested-by: NKitae Lee <kitae87.lee@samsung.com>
Reviewed-by: NJan Kara <jack@suse.cz>

Support the GETFSMAP ioctls so that we can use the xfs free space
management tools to probe ext4 as well.  Note that this is a partial
implementation -- we only report fixed-location metadata and free space;
everything else is reported as "unknown".
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Recent commits require line continuing printks to always use
pr_cont or KERN_CONT.  Add these markings to a few more printks.

Miscellaneaous:

o Integrate the ea_idebug and ea_bdebug macros to use a single
  call to printk(KERN_DEBUG instead of 3 separate printks
o Use the more common varargs macro style
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>

the error is:
    fs/ext4/mballoc.c:475:43: error: 'struct ext4_group_info' has
no member named 'bb_bitmap'.
    so, the definition of macro DOUBLE_CHECK should before
'struct ext4_group_info', I fixed it, and I moved the macro
AGGRESSIVE_CHECK together, because I think they shoule be together.
Signed-off-by: NAihua Zhang <zhangaihua1@huawei.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

When looking at a bug report with:

> kernel: EXT4-fs: 0 scanned, 0 found

I thought wow, 0 scanned, that's odd?  But it's not odd; it's printing
a variable that is initialized to 0 and never touched again.

It's never been used since the original merge, so I don't really even
know what the original intent was, either.

If anyone knows how to hook it up, speak now via patch, otherwise just
yank it so it's not making a confusing situation more confusing in
kernel logs.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

When !defined(CONFIG_EXT4_DEBUG), mb_debug() should be defined as a
no_printk() statement instead of an empty statement in order to suppress
the following compiler warning:

fs/ext4/mballoc.c: In function ‘ext4_mb_cleanup_pa’:
fs/ext4/mballoc.c:2659:47: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
   mb_debug(1, "mballoc: %u PAs left\n", count);
Signed-off-by: NPatrick Palka <patrick@parcs.ath.cx>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

There are multiple reasons to move away from debugfs.  First of all,
we are only using it for a single parameter, and it is much more
complicated to set up (some 30 lines of code compared to 3), and one
more thing that might fail while loading the ext4 module.

Secondly, as a module paramter it can be specified as a boot option if
ext4 is built into the kernel, or as a parameter when the module is
loaded, and it can also be manipulated dynamically under
/sys/module/ext4/parameters/mballoc_debug.  So it is more flexible.

Ultimately we want to move away from using mb_debug() towards
tracepoints, but for now this is still a useful simplification of the
code base.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Signed-off-by: NRobin Dong <sanbai@taobao.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The EXT4_MB_BITMAP and EXT4_MB_BUDDY macros obfuscate more than they
provide any abstraction.   So remove them.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The per-commit callback was used by mballoc code to manage free space
bitmaps after deleted blocks have been released.  This patch expands
it to support multiple different callbacks, to allow other things to
be done after the commit has been completed.
Signed-off-by: NBobi Jam <bobijam@whamcloud.com>
Signed-off-by: NAndreas Dilger <adilger@whamcloud.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

This patch changes "bext" to "best".
Signed-off-by: NRobin Dong <sanbai@taobao.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The ext4_free_blocks() function now has two new flags that indicate
whether a partial cluster at the beginning or the end of the block
extents should be freed or not.  That will be up the caller (i.e.,
truncate), who can figure out whether partial clusters at the
beginning or the end of a block range can be freed.

We also have to update the ext4_mb_free_metadata() and
release_blocks_on_commit() machinery to be cluster-based, since it is
used by ext4_free_blocks().
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

In most of mballoc.c, we do everything in units of clusters, since the
block allocation bitmaps and buddy bitmaps are all denominated in
clusters.  The one place where we do deal with absolute block numbers
is in the code that handles the preallocation regions, since in the
case of inode-based preallocation regions, the start of the
preallocation region can't be relative to the beginning of the group.

So this adds a bit of complexity, where pa_pstart and pa_lstart are
block numbers, while pa_free, pa_len, and fe_len are denominated in
units of clusters.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Certain parts of the ext4 code base, primarily in mballoc.c, use a
block group number and offset from the beginning of the block group.
This offset is invariably used to index into the allocation bitmap, so
change the offset to be denominated in units of clusters.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

ac_repeats isn't referenced in the mballoc code. So remove it.
Signed-off-by: NTao Ma <boyu.mt@taobao.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

After taking care of all group init races, all that remains is to
remove alloc_semp from ext4_allocation_context and ext4_buddy structs.
Signed-off-by: NAmir Goldstein <amir73il@users.sf.net>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Signed-off-by: NColy Li <bosong.ly@taobao.com>
Cc: Alex Tomas <alex@clusterfs.com>
Cc: Theodore Tso <tytso@google.com>

There are duplicate macro definitions of in_range() in mballoc.h and
balloc.c.  This consolidates these two definitions into ext4.h, and
changes extents.c to use in_range() as well.
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>

Remove unused #include <linux/version.h>('s) in
  fs/ext4/block_validity.c
  fs/ext4/mballoc.h
Signed-off-by: NHuang Weiyi <weiyi.huang@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

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>

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>

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>

Move the function prototypes in group.h into ext4.h so they are all
defined in one place.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

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

Impact: code cleanup

This patch rename pa_linear to pa_type and add MB_INODE_PA
and MB_GROUP_PA to indicate inode and group prealloc space.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Remove some leftovers from when the old block allocator was removed
(c2ea3fde).  ext4_sb_info is now a bit lighter.  Also remove a dangling
read_block_bitmap() prototype.
Signed-off-by: NMike Snitzer <snitzer@gmail.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

After we mark the blocks in the buddy cache as allocated,
we need to ensure that we don't reinit the buddy cache until
the block bitmap is updated.  This commit achieves this by holding
the group_info alloc_semaphore till ext4_mb_release_context
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org

The mballoc code likes to call ext4_error while it is holding locked
block groups.  This can causes a scheduling in atomic context BUG.  We
can't just unlock the block group and relock it after/if ext4_error
returns since that might result in race conditions in the case where
the filesystem is set to continue after finding errors.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Move some of the forward declaration of the static functions
to mballoc.c where they are used. This enables us to include
mballoc.h in other .c files. Also correct the buddy cache
documentation.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

The new groups added during resize are flagged as
need_init group. Make sure we properly initialize these
groups. When we have block size < page size and we are adding
new groups the page may still be marked uptodate even though
we haven't initialized the group. While forcing the init
of buddy cache we need to make sure other groups part of the
same page of buddy cache is not using the cache.
group_info->alloc_sem is added to ensure the same.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
cc: stable@kernel.org

The multiblock allocator needs to be able to release blocks (and issue
a blkdev discard request) when the transaction which freed those
blocks is committed.  Previously this was done via a polling mechanism
when blocks are allocated or freed.  A much better way of doing things
is to create a jbd2 callback function and attaching the list of blocks
to be freed directly to the transaction structure.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Let the block device know when unused blocks can be discarded, using
the new sb_issue_discard() interface.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

With this patch we track the block freed during a transaction using
red-black tree.  We also make sure contiguous blocks freed are collected
in one node in the tree.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

...and into the core setup/teardown code in fs/ext4/super.c so that
other parts of ext4 can define tuning parameters.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

Currently, the locality group prealloc list is freed only when there
is a block allocation failure. This can result in large number of
entries in the preallocation list making ext4_mb_use_preallocated()
expensive.

To fix this, we convert the locality group prealloc list to a hash
list. The hash index is the order of number of blocks in the prealloc
space with a max order of 9. When adding prealloc space to the list we
make sure total entries for each order does not exceed 8. If it is
more than 8 we discard few entries and make sure the we have only <= 5
entries.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Move function and structure definiations out of mballoc.c and put it under
a new header file mballoc.h
Signed-off-by: NMingming Cao <cmm@us.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>