This patch introduces a new ioctl F2FS_IOC_DEFRAGMENT to support file
defragment in a specified range of regular file.

This ioctl can be used in very limited workload: if user expects high
sequential read performance in randomly written file, this interface
can be used for defragmentation, after that file can be written as
continuous as possible in the device.

Meanwhile, it has side-effect, it will make holes in segments where
blocks located originally, so it's better to trigger GC to eliminate
fragment in segments.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

We should always commit atomic written pages in LFS mode, otherwise data
will become corrupted if we encounter suddent power cut after partial
pages committed in IPU mode.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

There is a FIEMAP_EXTENT_INLINE_DATA, pointed out by Marc.
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Users expect bmap will give allocated block addresses.
Let's play likewise ext4.
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

 different competitors

Since we use different page cache (normally inode's page cache for R/W
and meta inode's page cache for GC) to cache the same physical block
which is belong to an encrypted inode. Writeback of these two page
cache should be exclusive, but now we didn't handle writeback state
well, so there may be potential racing problem:

a)
kworker:				f2fs_gc:
 - f2fs_write_data_pages
  - f2fs_write_data_page
   - do_write_data_page
    - write_data_page
     - f2fs_submit_page_mbio
(page#1 in inode's page cache was queued
in f2fs bio cache, and be ready to write
to new blkaddr)
					 - gc_data_segment
					  - move_encrypted_block
					   - pagecache_get_page
					(page#2 in meta inode's page cache
					was cached with the invalid datas
					of physical block located in new
					blkaddr)
					   - f2fs_submit_page_mbio
					(page#1 was submitted, later, page#2
					with invalid data will be submitted)

b)
f2fs_gc:
 - gc_data_segment
  - move_encrypted_block
   - f2fs_submit_page_mbio
(page#1 in meta inode's page cache was
queued in f2fs bio cache, and be ready
to write to new blkaddr)
					user thread:
					 - f2fs_write_begin
					  - f2fs_submit_page_bio
					(we submit the request to block layer
					to update page#2 in inode's page cache
					with physical block located in new
					blkaddr, so here we may read gabbage
					data from new blkaddr since GC hasn't
					writebacked the page#1 yet)

This patch fixes above potential racing problem for encrypted inode.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch adds a tracepoint for f2fs_read_data_pages to trace when pages
are readahead by VFS.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

For normal inodes, their pages are allocated with __GFP_FS, which can cause
filesystem calls when reclaiming memory.
This can incur a dead lock condition accordingly.

So, this patch addresses this problem by introducing
f2fs_grab_cache_page(.., bool for_write), which calls
grab_cache_page_write_begin() with AOP_FLAG_NOFS.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

The periodic checkpoint can resolve the previous issue.
So, now we can use this again to improve the reported performance regression:

https://lkml.org/lkml/2015/10/8/20

This reverts commit 15bec0ff5a9ba6d203178fa8772259df6207942a.

Previously, we skip dentry block writes when wbc is SYNC_NONE with no memory
pressure and the number of dirty pages is pretty small.

But, we didn't skip for normal data writes, which gives us not much big impact
on overall performance.
Moreover, by skipping some data writes, kworker falls into infinite loop to try
to write blocks, when many dir inodes have only one dentry block.

So, this patch removes skipping data writes.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

We introduce F2FS_GET_BLOCK_READ in commit e2b4e2bc ("f2fs: fix
incorrect mapping for bmap"), but forget to use this flag in the right
place, fix it.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Here is a oops reported as following message when testing generic/019 of
xfstest:

 ------------[ cut here ]------------
 kernel BUG at /home/yuchao/git/f2fs-dev/segment.c:882!
 invalid opcode: 0000 [#1] SMP
 Modules linked in: zram lz4_compress lz4_decompress f2fs(O) ip6table_filter ip6_tables ebtable_nat ebtables nf_conntrack_ipv4
nf_def
 CPU: 2 PID: 25441 Comm: fio Tainted: G           O    4.3.0-rc1+ #6
 Hardware name: Hewlett-Packard HP Z220 CMT Workstation/1790, BIOS K51 v01.61 05/16/2013
 task: ffff8803f4e85580 ti: ffff8803fd61c000 task.ti: ffff8803fd61c000
 RIP: 0010:[<ffffffffa0784981>]  [<ffffffffa0784981>] new_curseg+0x321/0x330 [f2fs]
 RSP: 0018:ffff8803fd61f918  EFLAGS: 00010246
 RAX: 00000000000007ed RBX: 0000000000000224 RCX: 000000000000001f
 RDX: 0000000000000800 RSI: ffffffffffffffff RDI: ffff8803f56f4300
 RBP: ffff8803fd61f978 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000000000024 R11: ffff8800d23bbd78 R12: ffff8800d0ef0000
 R13: 0000000000000224 R14: 0000000000000000 R15: 0000000000000001
 FS:  00007f827ff85700(0000) GS:ffff88041ea80000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: ffffffffff600000 CR3: 00000003fef17000 CR4: 00000000001406e0
 Stack:
  000007ea00000002 0000000100000001 ffff8803f6456248 000007ed0000002b
  0000000000000224 ffff880404d1aa20 ffff8803fd61f9c8 ffff8800d0ef0000
  ffff8803f6456248 0000000000000001 00000000ffffffff ffffffffa078f358
 Call Trace:
  [<ffffffffa0785b87>] allocate_segment_by_default+0x1a7/0x1f0 [f2fs]
  [<ffffffffa078322c>] allocate_data_block+0x17c/0x360 [f2fs]
  [<ffffffffa0779521>] __allocate_data_block+0x131/0x1d0 [f2fs]
  [<ffffffffa077a995>] f2fs_direct_IO+0x4b5/0x580 [f2fs]
  [<ffffffff811510ae>] generic_file_direct_write+0xae/0x160
  [<ffffffff811518f5>] __generic_file_write_iter+0xd5/0x1f0
  [<ffffffff81151e07>] generic_file_write_iter+0xf7/0x200
  [<ffffffff81319e38>] ? apparmor_file_permission+0x18/0x20
  [<ffffffffa0768480>] ? f2fs_fallocate+0x1190/0x1190 [f2fs]
  [<ffffffffa07684c6>] f2fs_file_write_iter+0x46/0x90 [f2fs]
  [<ffffffff8120b4fe>] aio_run_iocb+0x1ee/0x290
  [<ffffffff81700f7e>] ? mutex_lock+0x1e/0x50
  [<ffffffff8120a1d7>] ? aio_read_events+0x207/0x2b0
  [<ffffffff8120b913>] do_io_submit+0x373/0x630
  [<ffffffff8120a4f6>] ? SyS_io_getevents+0x56/0xb0
  [<ffffffff8120bbe0>] SyS_io_submit+0x10/0x20
  [<ffffffff81703857>] entry_SYSCALL_64_fastpath+0x12/0x6a
 Code: 45 c8 48 8b 78 10 e8 9f 23 bf e0 41 8b 8c 24 cc 03 00 00 89 c7 31 d2 89 c6 89 d8 29 df f7 f1 29 d1 39 cf 0f 83 be fd ff ff eb
 RIP  [<ffffffffa0784981>] new_curseg+0x321/0x330 [f2fs]
  RSP <ffff8803fd61f918>
 ---[ end trace 2e577d7f711ddb86 ]---

The reason is that: in the test of generic/019, we will trigger a manmade
IO error in block layer through debugfs, after that, prefree segment will
no longer be freed, because we always skip doing gc or checkpoint when
there occurs an IO error.

Meanwhile fio with aio engine generated a large number of direct IOs,
which continue allocating spaces in free segment until we run out of them,
eventually, results in panic in new_curseg as no more free segment was
found.

So, this patch changes to return EIO in direct_IO for this condition.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

In this patch, we try to reorganize f2fs_map_blocks to make block mapping
flow more clear by using following structure:

/* check status of mapping */

if (unmapped) {
	/* blkaddr == NULL_ADDR || blkaddr == NEW_ADDR */

	if (create) {
		/* write path, handle dio write case here */
		alloc_and_map;
	} else {
		/*
		 * handle read cases from all call paths:
		 *     1. generic read;
		 *     2. dio read;
		 *     3. fiemap;
		 *     4. bmap
		 */
	}
}

/* map buffer_header */

Besides, this patch handles the missing case correctly for dio write:
When we fail in __allocate_data_blocks, then in f2fs_map_blocks, we will
not allocate blocks correctly for preallocated blocks, but returning with
an unmapped buffer head, which will result in failure of dio write.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

We have potential overflow issue when calculating size of object, when
we left shift index with PAGE_CACHE_SHIFT bits, if type of index has only
32-bits space in 32-bit architecture, left shifting will incur overflow,
i.e:

pgoff_t index =  0xFFFFFFFF;
loff_t size = index << PAGE_CACHE_SHIFT;
size: 0xFFFFF000

So we should cast index with 64-bits type to avoid this issue.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

The test step is like below:
1. touch file
2. truncate -s $((1024*1024)) file
3. fallocate -o 0 -l $((1024*1024)) file
4. fibmap.f2fs file

Our result of fibmap.f2fs showed below is not correct:

file_pos   start_blk     end_blk        blks
       0    -937166132    -937166132           1
    4096    -937166132    -937166132           1
    8192    -937166132    -937166132           1
   12288    -937166132    -937166132           1
   16384    -937166132    -937166132           1
   20480    -937166132    -937166132           1
...
 1040384    -937166132    -937166132           1
 1044480    -937166132    -937166132           1

This is because f2fs_map_blocks will return with no error when meeting
a hole or preallocated block, the caller __get_data_block will map the
uninitialized variable value to bh->b_blocknr.

Unfortunately generic_block_bmap will neither check the return value of
get_data() nor check mapping info of buffer_head, result in returning
the random block address.

After fixing the issue, our result shows correctly:

file_pos   start_blk     end_blk        blks
       0           0           0         256
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

As the below comment of bio_alloc_bioset, f2fs can allocate multiple bios at the
same time. So, we can't guarantee that bio is allocated all the time.

"
 *   When @bs is not NULL, if %__GFP_WAIT is set then bio_alloc will always be
 *   able to allocate a bio. This is due to the mempool guarantees. To make this
 *   work, callers must never allocate more than 1 bio at a time from this pool.
 *   Callers that need to allocate more than 1 bio must always submit the
 *   previously allocated bio for IO before attempting to allocate a new one.
 *   Failure to do so can cause deadlocks under memory pressure.
"
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

We can always fill up the bio now, no need to estimate the possible
size based on queue parameters.
Acked-by: NSteven Whitehouse <swhiteho@redhat.com>
Signed-off-by: NKent Overstreet <kent.overstreet@gmail.com>
[hch: rebased and wrote a changelog]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMing Lin <ming.l@ssi.samsung.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Previously, we use radix tree to index all registered page entries for
atomic file, but now we only use radix tree to see whether current page
is indexed or not, since the other user of radix tree is gone in commit
042b7816 ("f2fs: remove unnecessary call to invalidate inmemory pages").

So in this patch, we try to use one more efficient way:
Introducing a macro ATOMIC_WRITTEN_PAGE, and setting it as page private
value to indicate page indexing status. By using this way, we can save
memory and lookup time.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

We run ltp testcase with f2fs and obtain a TFAIL in diotest4, the result in
detail is as fallow:

dio04

<<<test_start>>>
tag=dio04 stime=1432278894
cmdline="diotest4"
contacts=""
analysis=exit
<<<test_output>>>
diotest4    1  TPASS  :  Negative Offset
diotest4    2  TPASS  :  removed
diotest4    3  TFAIL  :  diotest4.c:129: write allows odd count.returns 1: Success
diotest4    4  TFAIL  :  diotest4.c:183: Odd count of read and write
diotest4    5  TPASS  :  Read beyond the file size
......

the result of ext4 with same environment:

dio04

<<<test_start>>>
tag=dio04 stime=1432259643
cmdline="diotest4"
contacts=""
analysis=exit
<<<test_output>>>
diotest4    1  TPASS  :  Negative Offset
diotest4    2  TPASS  :  removed
diotest4    3  TPASS  :  Odd count of read and write
diotest4    4  TPASS  :  Read beyond the file size
......

The reason is that when triggering DIO in f2fs, we will return zero value
in ->direct_IO if writer's buffer offset, file offset and transfer size is
not alignment to block size of filesystem, resulting in falling back into
buffered write instead of returning -EINVAL.

This patch fixes that problem by returning correct error number for above
case, and removing the judgement condition in check_direct_IO to make sure
the verification will be enabled for direct reader too.

Besides, Jaegeuk Kim pointed out that there is expectional cases we should
always make direct-io falling back into buffered write, such as dio in
encrypted file.
Signed-off-by: NYunlei He <heyunlei@huawei.com>
[Chao Yu make small change and add detail description in commit message]
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

In some cases, we only need the block address when we call
f2fs_reserve_block,
other fields of struct dnode_of_data aren't necessary.
We can try extent cache first for such cases in order to speed up the
process.
Signed-off-by: NFan li <fanofcode.li@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

In following call path, we will pass a locked and referenced ipage
pointer to get_new_data_page:
 - init_inode_metadata
  - make_empty_dir
   - get_new_data_page

There are two exit paths in get_new_data_page when error occurs:
1) grab_cache_page fails, ipage will not be released;
2) f2fs_reserve_block fails, ipage will be released in callee.

So, it's not consistent for error handling in get_new_data_page.

For f2fs_reserve_block, it's not very easy to change the rule
of error handling, since it's already complicated.

Here we deside to choose an easy way to fix this issue:
If any error occur in get_new_data_page, we will ensure releasing
ipage in this function.

The same issue is in f2fs_convert_inline_dir, fix that too.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

some backing devices need pages to be stable during writeback. It doesn't
matter if
the page is completely overwritten or already uptodate, it needs to wait
before write.
Signed-off-by: NFan li <fanofcode.li@samsung.com>
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

When flushing comes from background, if there is no dirty page in the
mapping of inode, we'd better to skip seeking dirty page from mapping
for writebacking.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

The if statement "goto continue_unlock" is exactly the same when
each if condition is true that is depended on the value of both
"step" and "is_cold_data(page)" are 0 or 1. That means when the
value of "step" equals to "is_cold_data(page)", the if condition
is true and the if statement "goto continue_unlock" appears only
once, so it can be optimized to reduce the duplicated code.
Signed-off-by: NTiezhu Yang <kernelpatch@126.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch changes for a caller to handle the page after its bio gets an error.
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

If there are gced dirty pages and normal dirty pages in the mapping
of one inode, we might writeback them alternately with discontinuous
block address, resulting in low performance.

This patch introduces f2fs_write_cache_pages with codes copied from
write_cache_pages in mm/page-writeback.c.

In this function, we refactor flow with two steps:
1) writeback all cold type pages.
2) writeback all non-cold type pages.

By using this method, f2fs will writeback dirty pages with the same
temperature in bunch mode, it makes writeouted block being with
more continuous address, so they can be merged as much as possible
in f2fs bio cache, and also it will reduce the chance of submiting
small IO from block layer.

Test environment: 8g nokia sd card (very old sd card, but it shows
better effect when testing with this patch, and with a 32g kingston
sd card, I didn't see much more improvement).

Test step:
1. touch testfile;
2. truncate -s 512K testfile;
3. write all pages with odd index;
4. trigger gc by ioctl;
5. write all pages with even index;
6. time fsync testfile.

before:
real	0m0.402s
user	0m0.000s
sys	0m0.000s

after:
real	0m0.143s
user	0m0.004s
sys	0m0.004s
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch moves extent cache related code from data.c into extent_cache.c
since extent cache is independent feature, and its codes are not relate to
others in data.c, it's better for us to maintain them in separated place.

There is no functionality change, but several small coding style fixes
including:
* rename __drop_largest_extent to f2fs_drop_largest_extent for exporting;
* rename misspelled word 'untill' to 'until';
* remove unneeded 'return' in the end of f2fs_destroy_extent_tree().
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Since only parts of extents longer than F2FS_MIN_EXTENT_LEN will
be kept in extent cache after split, extents already shorter than
F2FS_MIN_EXTENT_LEN don't need to try split at all.
Signed-off-by: NFan Li <fanofcode.li@samsung.com>
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch fixes to update page flag (e.g. Uptodate/cold flag) in
->write_begin.

Otherwise, page will be non-uptodate when we try to write entire
page, and cold data flag in page will not be clean when gced page
is being rewritten.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

If an extent_tree entry has a zero reference count, we can drop it from the
cache in higher priority rather than currently referencing entries.
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

In ->writepages, we use writepages mutex lock to serialize all block
address allocation and page submitting pairs from different inodes.
This method makes our delayed dirty pages of one inode being written
continously as many as possible.

But there is one problem that we did not submit current cached bio in
protection region of writepages mutex lock, so there is a small chance
that we submit the one of other thread's as below, resulting in
splitting more bios.

thread 1			thread 2
->writepages
  lock(writepages)
  ->write_cache_pages
  unlock(writepages)
				  lock(writepages)
				  ->write_cache_pages
  ->f2fs_submit_merged_bio
				    ->writepage
				  unlock(writepages)

fs_mark-6535  [002] ....  2242.270230: f2fs_submit_write_bio: dev = (1,0), WRITE_SYNC, DATA, sector = 5766152, size = 524288
fs_mark-6536  [000] ....  2242.270361: f2fs_submit_write_bio: dev = (1,0), WRITE_SYNC, DATA, sector = 5767176, size = 4096
fs_mark-6536  [000] ....  2242.270370: f2fs_submit_write_bio: dev = (1,0), WRITE_SYNC, NODE, sector = 8138112, size = 4096
fs_mark-6535  [002] ....  2242.270776: f2fs_submit_write_bio: dev = (1,0), WRITE_SYNC, DATA, sector = 5767184, size = 516096

This may really increase time of block layer works, and may cause
larger IO lantency.

This patch moves the submitting operation into region of writepages
mutex lock to avoid bio splits when concurrently writebacking is
intensive.

my test environment: virtual machine,
intel cpu i5 2500, 8GB size memory, 4GB size ramdisk

time fs_mark  -t  16  -L  1  -s  524288  -S  1  -d  /mnt/f2fs/

before:
real	0m4.244s
user	0m0.088s
sys	0m12.336s

after:
real	0m3.822s
user	0m0.072s
sys	0m10.760s
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Because of the extent shrinker or other -ENOMEM scenarios, it cannot guarantee
that the largest extent would be cached in the tree all the time.

Instead of relying on extent_tree, we can simply check the cached one in extent
tree accordingly.
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

We don't need to handle the duplicate extent information.

The integrated rule is:
 - update on-disk extent with largest one tracked by in-memory extent_cache
 - destroy extent_tree for the truncation case
 - drop per-inode extent_cache by shrinker
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch registers shrinking extent_caches.
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch relocates cached_en not only to be covered by spin_lock, but also
to set once after checking out completely.
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Previously, f2fs_update_extent_cache() updates in-memory extent_cache all the
time, and then finally preserves its up-to-date extent into on-disk one during
f2fs_evict_inode.

But, in the following scenario:

1. mount
2. open & write an extent X
3. f2fs_evict_inode; on-disk extent is X
4. open & update the extent X with Y
5. sync; trigger checkpoint
6. power-cut

after power-on, f2fs should serve extent Y, but we have an on-disk extent X.

This causes a failure on xfstests/311.
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch fixes wrong calculation on block address field when an extent is
split.
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Currently we have two different ways to signal an I/O error on a BIO:

 (1) by clearing the BIO_UPTODATE flag
 (2) by returning a Linux errno value to the bi_end_io callback

The first one has the drawback of only communicating a single possible
error (-EIO), and the second one has the drawback of not beeing persistent
when bios are queued up, and are not passed along from child to parent
bio in the ever more popular chaining scenario.  Having both mechanisms
available has the additional drawback of utterly confusing driver authors
and introducing bugs where various I/O submitters only deal with one of
them, and the others have to add boilerplate code to deal with both kinds
of error returns.

So add a new bi_error field to store an errno value directly in struct
bio and remove the existing mechanisms to clean all this up.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

The cgroup attaches inode->i_wb via mark_inode_dirty and when set_page_writeback
is called, __inc_wb_stat() updates i_wb's stat.

So, we need to explicitly call set_page_dirty->__mark_inode_dirty in prior to
any writebacking pages.

This patch should resolve the following kernel panic reported by Andreas Reis.

https://bugzilla.kernel.org/show_bug.cgi?id=101801

--- Comment #2 from Andreas Reis <andreas.reis@gmail.com> ---
BUG: unable to handle kernel NULL pointer dereference at 00000000000000a8
IP: [<ffffffff8149deea>] __percpu_counter_add+0x1a/0x90
PGD 2951ff067 PUD 2df43f067 PMD 0
Oops: 0000 [#1] PREEMPT SMP
Modules linked in:
CPU: 7 PID: 10356 Comm: gcc Tainted: G        W       4.2.0-1-cu #1
Hardware name: Gigabyte Technology Co., Ltd. G1.Sniper M5/G1.Sniper M5, BIOS
T01 02/03/2015
task: ffff880295044f80 ti: ffff880295140000 task.ti: ffff880295140000
RIP: 0010:[<ffffffff8149deea>]  [<ffffffff8149deea>]
__percpu_counter_add+0x1a/0x90
RSP: 0018:ffff880295143ac8  EFLAGS: 00010082
RAX: 0000000000000003 RBX: ffffea000a526d40 RCX: 0000000000000001
RDX: 0000000000000020 RSI: 0000000000000001 RDI: 0000000000000088
RBP: ffff880295143ae8 R08: 0000000000000000 R09: ffff88008f69bb30
R10: 00000000fffffffa R11: 0000000000000000 R12: 0000000000000088
R13: 0000000000000001 R14: ffff88041d099000 R15: ffff880084a205d0
FS:  00007f8549374700(0000) GS:ffff88042f3c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000000a8 CR3: 000000033e1d5000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000000 ffffea000a526d40 ffff880084a20738 ffff880084a20750
 ffff880295143b48 ffffffff811cc91e ffff880000000000 0000000000000296
 0000000000000000 ffff880417090198 0000000000000000 ffffea000a526d40
Call Trace:
 [<ffffffff811cc91e>] __test_set_page_writeback+0xde/0x1d0
 [<ffffffff813fee87>] do_write_data_page+0xe7/0x3a0
 [<ffffffff813faeea>] gc_data_segment+0x5aa/0x640
 [<ffffffff813fb0b8>] do_garbage_collect+0x138/0x150
 [<ffffffff813fb3fe>] f2fs_gc+0x1be/0x3e0
 [<ffffffff81405541>] f2fs_balance_fs+0x81/0x90
 [<ffffffff813ee357>] f2fs_unlink+0x47/0x1d0
 [<ffffffff81239329>] vfs_unlink+0x109/0x1b0
 [<ffffffff8123e3d7>] do_unlinkat+0x287/0x2c0
 [<ffffffff8123ebc6>] SyS_unlink+0x16/0x20
 [<ffffffff81942e2e>] entry_SYSCALL_64_fastpath+0x12/0x71
Code: 41 5e 5d c3 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 41 55 49
89 f5 41 54 49 89 fc 53 48 83 ec 08 65 ff 05 e6 d9 b6 7e <48> 8b 47 20 48 63 ca
65 8b 18 48 63 db 48 01 f3 48 39 cb 7d 0a
RIP  [<ffffffff8149deea>] __percpu_counter_add+0x1a/0x90
 RSP <ffff880295143ac8>
CR2: 00000000000000a8
---[ end trace 5132449a58ed93a3 ]---
note: gcc[10356] exited with preempt_count 2
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch tries to clean up code because part code of f2fs_read_end_io
and mpage_end_io are the same, so it's better to merge and reuse them.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch adds encryption support in read and write paths.

Note that, in f2fs, we need to consider cleaning operation.
In cleaning procedure, we must avoid encrypting and decrypting written blocks.
So, this patch implements move_encrypted_block().
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>