Although mixed sync/async IOs can have continuous LBA, as they have
different IO priority, block IO scheduler will add them into different
queues and commit them separately, result in splited IOs which causes
wrose performance.

This patch gives high priority to synchronous IO of nodes, means that
once synchronous flow starts, it can interrupt asynchronous writeback
flow of system flusher, so more big IOs can be expected.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

As Ted reported:

"Hi, I was looking at f2fs's sources recently, and I noticed that there
is a very large number of non-static symbols which don't have a f2fs
prefix.  There's well over a hundred (see attached below).

As one example, in fs/f2fs/dir.c there is:

unsigned char get_de_type(struct f2fs_dir_entry *de)

This function is clearly only useful for f2fs, but it has a generic
name.  This means that if any other file system tries to have the same
symbol name, there will be a symbol conflict and the kernel would not
successfully build.  It also means that when someone is looking f2fs
sources, it's not at all obvious whether a function such as
read_data_page(), invalidate_blocks(), is a generic kernel function
found in the fs, mm, or block layers, or a f2fs specific function.

You might want to fix this at some point.  Hopefully Kent's bcachefs
isn't similarly using genericly named functions, since that might
cause conflicts with f2fs's functions --- but just as this would be a
problem that we would rightly insist that Kent fix, this is something
that we should have rightly insisted that f2fs should have fixed
before it was integrated into the mainline kernel.

acquire_orphan_inode
add_ino_entry
add_orphan_inode
allocate_data_block
allocate_new_segments
alloc_nid
alloc_nid_done
alloc_nid_failed
available_free_memory
...."

This patch adds "f2fs_" prefix for all non-static symbols in order to:
a) avoid conflict with other kernel generic symbols;
b) to indicate the function is f2fs specific one instead of generic
one;
Reported-by: NTheodore Ts'o <tytso@mit.edu>
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Configure io_bits with 2 and enable LFS mode, generic/013 reports below dmesg:

BUG: unable to handle kernel NULL pointer dereference at 00000104
*pdpt = 0000000029b7b001 *pde = 0000000000000000
Oops: 0002 [#1] PREEMPT SMP
Modules linked in: crc32_generic zram f2fs(O) rfcomm bnep bluetooth ecdh_generic snd_intel8x0 snd_ac97_codec ac97_bus snd_pcm snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq pcbc joydev snd_seq_device aesni_intel snd_timer aes_i586 snd crypto_simd cryptd soundcore i2c_piix4 serio_raw mac_hid video parport_pc ppdev lp parport hid_generic psmouse usbhid hid e1000
CPU: 0 PID: 11161 Comm: fsstress Tainted: G           O      4.17.0-rc2 #38
Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
EIP: f2fs_submit_page_write+0x28d/0x550 [f2fs]
EFLAGS: 00010206 CPU: 0
EAX: e863dcd8 EBX: 00000000 ECX: 00000100 EDX: 00000200
ESI: e863dcf4 EDI: f6f82768 EBP: e863dbb0 ESP: e863db74
 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
CR0: 80050033 CR2: 00000104 CR3: 29a62020 CR4: 000406f0
Call Trace:
 do_write_page+0x6f/0xc0 [f2fs]
 write_data_page+0x4a/0xd0 [f2fs]
 do_write_data_page+0x327/0x630 [f2fs]
 __write_data_page+0x34b/0x820 [f2fs]
 __f2fs_write_data_pages+0x42d/0x8c0 [f2fs]
 f2fs_write_data_pages+0x27/0x30 [f2fs]
 do_writepages+0x1a/0x70
 __filemap_fdatawrite_range+0x94/0xd0
 filemap_write_and_wait_range+0x3d/0xa0
 __generic_file_write_iter+0x11a/0x1f0
 f2fs_file_write_iter+0xdd/0x3b0 [f2fs]
 __vfs_write+0xd2/0x150
 vfs_write+0x9b/0x190
 ksys_write+0x45/0x90
 sys_write+0x16/0x20
 do_fast_syscall_32+0xaa/0x22c
 entry_SYSENTER_32+0x4c/0x7b
EIP: 0xb7fc8c51
EFLAGS: 00000246 CPU: 0
EAX: ffffffda EBX: 00000003 ECX: 09cde000 EDX: 00001000
ESI: 00000003 EDI: 00001000 EBP: 00000000 ESP: bfbded38
 DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b
Code: e8 f9 77 34 c9 8b 45 e0 8b 80 b8 00 00 00 39 45 d8 0f 84 bb 02 00 00 8b 45 e0 8b 80 b8 00 00 00 8d 50 d8 8b 08 89 55 f0 8b 50 04 <89> 51 04 89 0a c7 00 00 01 00 00 c7 40 04 00 02 00 00 8b 45 dc
EIP: f2fs_submit_page_write+0x28d/0x550 [f2fs] SS:ESP: 0068:e863db74
CR2: 0000000000000104
---[ end trace 4cac79c0d1305ee6 ]---

allocate_data_block will submit all sequential pending IOs sorted by a
FIFO list, If we failed to submit other user's IO due to unaligned write,
we will retry to allocate new block address for current IO, then it will
initialize fio.list again, if fio was in the list before, it can break
FIFO list, result in above panic.

Thread A			Thread B
- do_write_page
 - allocate_data_block
  - list_add_tail
  : fioA cached in FIFO list.
				- do_write_page
				 - allocate_data_block
				  - list_add_tail
				  : fioB cached in FIFO list.
				 - f2fs_submit_page_write
				 : fail to submit IO
				 - allocate_data_block
				  - INIT_LIST_HEAD
 - f2fs_submit_page_write
  - list_del  <-- NULL pointer dereference

This patch adds fio.retry parameter to indicate failure status for each
IO, and avoid bailing out if there is still pending IO in FIFO list for
fixing.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch fixes error path of move_data_page:
- clear cold data flag if it fails to write page.
- redirty page for non-ENOMEM case.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

f2fs doesn't allow abuse on atomic write class interface, so except
limiting in-mem pages' total memory usage capacity, we need to limit
atomic-write usage as well when filesystem is seriously fragmented,
otherwise we may run into infinite loop during foreground GC because
target blocks in victim segment are belong to atomic opened file for
long time.

Now, we will detect failure due to atomic write in foreground GC, if
the count exceeds threshold, we will drop all atomic written data in
cache, by this, I expect it can keep our system running safely to
prevent Dos attack.

In addition, his patch adds to show GC skip information in debugfs,
now it just shows count of skipped caused by atomic write.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This is to avoid sbi->gc_thread pointer access.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

For non-migration IO, we will keep order of data/node blocks' submitting
as allocation sequence by sorting IOs in per log io_list list, but for
migration IO, it could be out-of-order.

In LFS mode, we should keep all IOs including migration IO be ordered,
so that this patch fixes to add an additional lock to keep submitting
order.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

For extreme case:
10 section, op = 10%, no_fggc_threshold = 90%
All section usage: 85% 85% 85% 85% 90% 90% 95% 95% 95% 95%

During foreground GC, if we skip select dirty section whose usage
is larger than no_fggc_threshold, we can only recycle 80% invalid
space from four 85% usage sections and two 90% usage sections,
result in encountering out-of-space issue.

This reverts commit e93b9865 to
fix this issue, besides, we keep the logic that we scan all dirty
section when searching a victim, so that GC can select victim with
least valid blocks.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

RW semphore dio_rwsem in struct f2fs_inode_info is introduced to avoid
race between dio and data gc, but now, it is more wildly used to avoid
foreground operation vs data gc. So rename it to i_gc_rwsem to improve
its readability.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch clears PageError in some pages tagged by read path, but when we
write the pages with valid contents, writepage should clear the bit likewise
ext4.
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Currently f2fs's ->readpage() and ->readpages() assume that either the
data undergoes no postprocessing, or decryption only.  But with
fs-verity, there will be an additional authenticity verification step,
and it may be needed either by itself, or combined with decryption.

To support this, store a 'struct bio_post_read_ctx' in ->bi_private
which contains a work struct, a bitmask of postprocessing steps that are
enabled, and an indicator of the current step.  The bio completion
routine, if there was no I/O error, enqueues the first postprocessing
step.  When that completes, it continues to the next step.  Pages that
fail any postprocessing step have PageError set.  Once all steps have
completed, pages without PageError set are set Uptodate, and all pages
are unlocked.

Also replace f2fs_encrypted_file() with a new function
f2fs_post_read_required() in places like direct I/O and garbage
collection that really should be testing whether the file needs special
I/O processing, not whether it is encrypted specifically.

This may also be useful for other future f2fs features such as
compression.
Signed-off-by: NEric Biggers <ebiggers@google.com>
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This results in no change in structure size on 64-bit machines as it
fits in the padding between the gfp_t and the void *.  32-bit machines
will grow the structure from 8 to 12 bytes.  Almost all radix trees are
protected with (at least) a spinlock, so as they are converted from
radix trees to xarrays, the data structures will shrink again.

Initialising the spinlock requires a name for the benefit of lockdep, so
RADIX_TREE_INIT() now needs to know the name of the radix tree it's
initialising, and so do IDR_INIT() and IDA_INIT().

Also add the xa_lock() and xa_unlock() family of wrappers to make it
easier to use the lock.  If we could rely on -fplan9-extensions in the
compiler, we could avoid all of this syntactic sugar, but that wasn't
added until gcc 4.6.

Link: http://lkml.kernel.org/r/20180313132639.17387-8-willy@infradead.orgSigned-off-by: NMatthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: NJeff Layton <jlayton@kernel.org>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Otherwise, f2fs conducts GC on 8GB range only based on slow cost-benefit.
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Let's do GC as much as possible, while gc_urgent is set.
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Commit 7a20b8a6 ("f2fs: allocate node
and hot data in the beginning of partition") introduces another mount
option, heap, to reset it back. But it does not do anything for heap
mode, so fix it.

Cc: stable@vger.kernel.org
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

When io_bits is set, GCing encrypted block may hit the following hungtask.
Since io_bits requires aligned block address, f2fs_submit_page_write may
return -EAGAIN if new_blkaddr does not satisify io_bits alignment. As a
result, the encrypted page will never be writtenback.

This patch makes move_data_block aware the EAGAIN error and cancel the
writeback.

[  246.751371] INFO: task kworker/u4:4:797 blocked for more than 90 seconds.
[  246.752423]       Not tainted 4.15.0-rc4+ #11
[  246.754176] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[  246.755336] kworker/u4:4    D25448   797      2 0x80000000
[  246.755597] Workqueue: writeback wb_workfn (flush-7:0)
[  246.755616] Call Trace:
[  246.755695]  ? __schedule+0x322/0xa90
[  246.755761]  ? blk_init_request_from_bio+0x120/0x120
[  246.755773]  ? pci_mmcfg_check_reserved+0xb0/0xb0
[  246.755801]  ? __radix_tree_create+0x19e/0x200
[  246.755813]  ? delete_node+0x136/0x370
[  246.755838]  schedule+0x43/0xc0
[  246.755904]  io_schedule+0x17/0x40
[  246.755939]  wait_on_page_bit_common+0x17b/0x240
[  246.755950]  ? wake_page_function+0xa0/0xa0
[  246.755961]  ? add_to_page_cache_lru+0x160/0x160
[  246.755972]  ? page_cache_tree_insert+0x170/0x170
[  246.755983]  ? __lru_cache_add+0x96/0xb0
[  246.756086]  __filemap_fdatawait_range+0x14f/0x1c0
[  246.756097]  ? wait_on_page_bit_common+0x240/0x240
[  246.756120]  ? __wake_up_locked_key_bookmark+0x20/0x20
[  246.756167]  ? wait_on_all_pages_writeback+0xc9/0x100
[  246.756179]  ? __remove_ino_entry+0x120/0x120
[  246.756192]  ? wait_woken+0x100/0x100
[  246.756204]  filemap_fdatawait_range+0x9/0x20
[  246.756216]  write_checkpoint+0x18a1/0x1f00
[  246.756254]  ? blk_get_request+0x10/0x10
[  246.756265]  ? cpumask_next_and+0x43/0x60
[  246.756279]  ? f2fs_sync_inode_meta+0x160/0x160
[  246.756289]  ? remove_element.isra.4+0xa0/0xa0
[  246.756300]  ? __put_compound_page+0x40/0x40
[  246.756310]  ? f2fs_sync_fs+0xec/0x1c0
[  246.756320]  ? f2fs_sync_fs+0x120/0x1c0
[  246.756329]  f2fs_sync_fs+0x120/0x1c0
[  246.756357]  ? trace_event_raw_event_f2fs__page+0x260/0x260
[  246.756393]  ? ata_build_rw_tf+0x173/0x410
[  246.756397]  f2fs_balance_fs_bg+0x198/0x390
[  246.756405]  ? drop_inmem_page+0x230/0x230
[  246.756415]  ? ahci_qc_prep+0x1bb/0x2e0
[  246.756418]  ? ahci_qc_issue+0x1df/0x290
[  246.756422]  ? __accumulate_pelt_segments+0x42/0xd0
[  246.756426]  ? f2fs_write_node_pages+0xd1/0x380
[  246.756429]  f2fs_write_node_pages+0xd1/0x380
[  246.756437]  ? sync_node_pages+0x8f0/0x8f0
[  246.756440]  ? update_curr+0x53/0x220
[  246.756444]  ? __accumulate_pelt_segments+0xa2/0xd0
[  246.756448]  ? __update_load_avg_se.isra.39+0x349/0x360
[  246.756452]  ? do_writepages+0x2a/0xa0
[  246.756456]  do_writepages+0x2a/0xa0
[  246.756460]  __writeback_single_inode+0x70/0x490
[  246.756463]  ? check_preempt_wakeup+0x199/0x310
[  246.756467]  writeback_sb_inodes+0x2a2/0x660
[  246.756471]  ? is_empty_dir_inode+0x40/0x40
[  246.756474]  ? __writeback_single_inode+0x490/0x490
[  246.756477]  ? string+0xbf/0xf0
[  246.756480]  ? down_read_trylock+0x35/0x60
[  246.756484]  __writeback_inodes_wb+0x9f/0xf0
[  246.756488]  wb_writeback+0x41d/0x4b0
[  246.756492]  ? writeback_inodes_wb.constprop.55+0x150/0x150
[  246.756498]  ? set_worker_desc+0xf7/0x130
[  246.756502]  ? current_is_workqueue_rescuer+0x60/0x60
[  246.756511]  ? _find_next_bit+0x2c/0xa0
[  246.756514]  ? wb_workfn+0x400/0x5d0
[  246.756518]  wb_workfn+0x400/0x5d0
[  246.756521]  ? finish_task_switch+0xdf/0x2a0
[  246.756525]  ? inode_wait_for_writeback+0x30/0x30
[  246.756529]  process_one_work+0x3a7/0x6f0
[  246.756533]  worker_thread+0x82/0x750
[  246.756537]  kthread+0x16f/0x1c0
[  246.756541]  ? trace_event_raw_event_workqueue_work+0x110/0x110
[  246.756544]  ? kthread_create_worker_on_cpu+0xb0/0xb0
[  246.756548]  ret_from_fork+0x1f/0x30
Signed-off-by: NSheng Yong <shengyong1@huawei.com>
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch gives a flag to disable GC on given file, which would be useful, when
user wants to keep its block map. It also conducts in-place-update for dontmove
file.
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This is a pure automated search-and-replace of the internal kernel
superblock flags.

The s_flags are now called SB_*, with the names and the values for the
moment mirroring the MS_* flags that they're equivalent to.

Note how the MS_xyz flags are the ones passed to the mount system call,
while the SB_xyz flags are what we then use in sb->s_flags.

The script to do this was:

    # places to look in; re security/*: it generally should *not* be
    # touched (that stuff parses mount(2) arguments directly), but
    # there are two places where we really deal with superblock flags.
    FILES="drivers/mtd drivers/staging/lustre fs ipc mm \
            include/linux/fs.h include/uapi/linux/bfs_fs.h \
            security/apparmor/apparmorfs.c security/apparmor/include/lib.h"
    # the list of MS_... constants
    SYMS="RDONLY NOSUID NODEV NOEXEC SYNCHRONOUS REMOUNT MANDLOCK \
          DIRSYNC NOATIME NODIRATIME BIND MOVE REC VERBOSE SILENT \
          POSIXACL UNBINDABLE PRIVATE SLAVE SHARED RELATIME KERNMOUNT \
          I_VERSION STRICTATIME LAZYTIME SUBMOUNT NOREMOTELOCK NOSEC BORN \
          ACTIVE NOUSER"

    SED_PROG=
    for i in $SYMS; do SED_PROG="$SED_PROG -e s/MS_$i/SB_$i/g"; done

    # we want files that contain at least one of MS_...,
    # with fs/namespace.c and fs/pnode.c excluded.
    L=$(for i in $SYMS; do git grep -w -l MS_$i $FILES; done| sort|uniq|grep -v '^fs/namespace.c'|grep -v '^fs/pnode.c')

    for f in $L; do sed -i $f $SED_PROG; done
Requested-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

During block exchange in {insert,collapse,move}_range, page-block mapping
is unstable due to mapping moving or recovery, so there should be no
concurrent cache read operation rely on such mapping, nor cache write
operation to mess up block exchange.

So this patch let background GC be aware of that.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

There are some cases user didn't update SIT cache under this lock,
so let's use rw_semaphore instead of mutex to enhance concurrently
accessing.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch adds to support get_page error injection to simulate
out-of-memory test scenario.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

When multiple device feature is enabled, during ->fsync we will issue
flush in all devices to make sure node/data of the file being persisted
into storage. But some flushes of device could be unneeded as file's
data may be not writebacked into those devices. So this patch adds and
manage bitmap per inode in global cache to indicate which device is
dirty and it needs to issue flush during ->fsync, hence, we could improve
performance of fsync in scenario of multiple device.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This reverts commit b9cd2061.

That patch causes much fewer node segments (which can be used for SSR)
than before, and in the corner case (e.g. create and delete *.txt files in
one same directory, there will be very few node segments but many data
segments), if the reserved free segments are all used up during gc, then
the write_checkpoint can still flush dentry pages to data ssr segments,
but will probably fail to flush node pages to node ssr segments, since
there are not enough node ssr segments left (the left ones are all
full).

So revert this patch to give a fair chance to let node segments remain
for SSR, which provides more robustness for corner cases.

Conflicts:
	fs/f2fs/gc.c
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch renames functions regarding to buffer management via META_MAPPING
used for encrypted blocks especially. We can actually use them in generic way.
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch replaces (f2fs_encrypted_inode() && S_ISREG()) with
f2fs_encrypted_file(), which gives no functional change.
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This reverts commit b7b7c4cf.

se->ckpt_valid_blocks will never be smaller than se->valid_blocks, so just
remove get_ssr_cost.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

We won't wait DIO synchronously when doing AIO, so there will be potential
IO reorder in between AIO and GC, which will cause data corruption.

This patch adds inode_dio_wait to serialize aio and data GC to avoid this
issue.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch adds tracepoint for f2fs_gc.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

While comparing signed and unsigned variables, compiler will converts the
signed value to unsigned one, due to this reason, {in,de}crease_sleep_time
may return overflowed result.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch adds a sysfs entry to control urgent mode for background GC.
If this is set, background GC thread conducts GC with gc_urgent_sleep_time
all the time.
Reviewed-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch enables inner app/fs io stats and introduces below virtual fs
nodes for exposing stats info:
/sys/fs/f2fs/<dev>/iostat_enable
/proc/fs/f2fs/<dev>/iostat_info
Signed-off-by: NChao Yu <yuchao0@huawei.com>
[Jaegeuk Kim: fix wrong stat assignment]
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch add new flag F2FS_EXTRA_ATTR storing in inode.i_inline
to indicate that on-disk structure of current inode is extended.

In order to extend, we changed the inode structure a bit:

Original one:

struct f2fs_inode {
	...
	struct f2fs_extent i_ext;
	__le32 i_addr[DEF_ADDRS_PER_INODE];
	__le32 i_nid[DEF_NIDS_PER_INODE];
}

Extended one:

struct f2fs_inode {
        ...
        struct f2fs_extent i_ext;
	union {
		struct {
			__le16 i_extra_isize;
			__le16 i_padding;
			__le32 i_extra_end[0];
		};
		__le32 i_addr[DEF_ADDRS_PER_INODE];
	};
        __le32 i_nid[DEF_NIDS_PER_INODE];
}

Once F2FS_EXTRA_ATTR is set, we will steal four bytes in the head of
i_addr field for storing i_extra_isize and i_padding. with i_extra_isize,
we can calculate actual size of reserved space in i_addr, available
attribute fields included in total extra attribute fields for current
inode can be described as below:

  +--------------------+
  | .i_mode            |
  | ...                |
  | .i_ext             |
  +--------------------+
  | .i_extra_isize     |-----+
  | .i_padding         |     |
  | .i_prjid           |     |
  | .i_atime_extra     |     |
  | .i_ctime_extra     |     |
  | .i_mtime_extra     |<----+
  | .i_inode_cs        |<----- store blkaddr/inline from here
  | .i_xattr_cs        |
  | ...                |
  +--------------------+
  |                    |
  |    block address   |
  |                    |
  +--------------------+
  | .i_nid             |
  +--------------------+
  |   node_footer      |
  | (nid, ino, offset) |
  +--------------------+

Hence, with this patch, we would enhance scalability of f2fs inode for
storing more newly added attribute.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

When ->freeze_fs is called from lvm for doing snapshot, it needs to
make sure there will be no more changes in filesystem's data, however,
previously, background threads like GC thread wasn't aware of freezing,
so in environment with active background threads, data of snapshot
becomes unstable.

This patch fixes this issue by adding sb_{start,end}_intwrite in
below background threads:
- GC thread
- flush thread
- discard thread

Note that, don't use sb_start_intwrite() in gc_thread_func() due to:

generic/241 reports below bug:

 ======================================================
 WARNING: possible circular locking dependency detected
 4.13.0-rc1+ #32 Tainted: G           O
 ------------------------------------------------------
 f2fs_gc-250:0/22186 is trying to acquire lock:
  (&sbi->gc_mutex){+.+...}, at: [<f8fa7f0b>] f2fs_sync_fs+0x7b/0x1b0 [f2fs]

 but task is already holding lock:
  (sb_internal#2){++++.-}, at: [<f8fb5609>] gc_thread_func+0x159/0x4a0 [f2fs]

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #2 (sb_internal#2){++++.-}:
        __lock_acquire+0x405/0x7b0
        lock_acquire+0xae/0x220
        __sb_start_write+0x11d/0x1f0
        f2fs_evict_inode+0x2d6/0x4e0 [f2fs]
        evict+0xa8/0x170
        iput+0x1fb/0x2c0
        f2fs_sync_inode_meta+0x3f/0xf0 [f2fs]
        write_checkpoint+0x1b1/0x750 [f2fs]
        f2fs_sync_fs+0x85/0x1b0 [f2fs]
        f2fs_do_sync_file.isra.24+0x137/0xa30 [f2fs]
        f2fs_sync_file+0x34/0x40 [f2fs]
        vfs_fsync_range+0x4a/0xa0
        do_fsync+0x3c/0x60
        SyS_fdatasync+0x15/0x20
        do_fast_syscall_32+0xa1/0x1b0
        entry_SYSENTER_32+0x4c/0x7b

 -> #1 (&sbi->cp_mutex){+.+...}:
        __lock_acquire+0x405/0x7b0
        lock_acquire+0xae/0x220
        __mutex_lock+0x4f/0x830
        mutex_lock_nested+0x25/0x30
        write_checkpoint+0x2f/0x750 [f2fs]
        f2fs_sync_fs+0x85/0x1b0 [f2fs]
        sync_filesystem+0x67/0x80
        generic_shutdown_super+0x27/0x100
        kill_block_super+0x22/0x50
        kill_f2fs_super+0x3a/0x40 [f2fs]
        deactivate_locked_super+0x3d/0x70
        deactivate_super+0x40/0x60
        cleanup_mnt+0x39/0x70
        __cleanup_mnt+0x10/0x20
        task_work_run+0x69/0x80
        exit_to_usermode_loop+0x57/0x92
        do_fast_syscall_32+0x18c/0x1b0
        entry_SYSENTER_32+0x4c/0x7b

 -> #0 (&sbi->gc_mutex){+.+...}:
        validate_chain.isra.36+0xc50/0xdb0
        __lock_acquire+0x405/0x7b0
        lock_acquire+0xae/0x220
        __mutex_lock+0x4f/0x830
        mutex_lock_nested+0x25/0x30
        f2fs_sync_fs+0x7b/0x1b0 [f2fs]
        f2fs_balance_fs_bg+0xb9/0x200 [f2fs]
        gc_thread_func+0x302/0x4a0 [f2fs]
        kthread+0xe9/0x120
        ret_from_fork+0x19/0x24

 other info that might help us debug this:

 Chain exists of:
   &sbi->gc_mutex --> &sbi->cp_mutex --> sb_internal#2

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(sb_internal#2);
                                lock(&sbi->cp_mutex);
                                lock(sb_internal#2);
   lock(&sbi->gc_mutex);

  *** DEADLOCK ***

 1 lock held by f2fs_gc-250:0/22186:
  #0:  (sb_internal#2){++++.-}, at: [<f8fb5609>] gc_thread_func+0x159/0x4a0 [f2fs]

 stack backtrace:
 CPU: 2 PID: 22186 Comm: f2fs_gc-250:0 Tainted: G           O    4.13.0-rc1+ #32
 Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
 Call Trace:
  dump_stack+0x5f/0x92
  print_circular_bug+0x1b3/0x1bd
  validate_chain.isra.36+0xc50/0xdb0
  ? __this_cpu_preempt_check+0xf/0x20
  __lock_acquire+0x405/0x7b0
  lock_acquire+0xae/0x220
  ? f2fs_sync_fs+0x7b/0x1b0 [f2fs]
  __mutex_lock+0x4f/0x830
  ? f2fs_sync_fs+0x7b/0x1b0 [f2fs]
  mutex_lock_nested+0x25/0x30
  ? f2fs_sync_fs+0x7b/0x1b0 [f2fs]
  f2fs_sync_fs+0x7b/0x1b0 [f2fs]
  f2fs_balance_fs_bg+0xb9/0x200 [f2fs]
  gc_thread_func+0x302/0x4a0 [f2fs]
  ? preempt_schedule_common+0x2f/0x4d
  ? f2fs_gc+0x540/0x540 [f2fs]
  kthread+0xe9/0x120
  ? f2fs_gc+0x540/0x540 [f2fs]
  ? kthread_create_on_node+0x30/0x30
  ret_from_fork+0x19/0x24

The deadlock occurs in below condition:
GC Thread			Thread B
- sb_start_intwrite
				- f2fs_sync_file
				 - f2fs_sync_fs
				  - mutex_lock(&sbi->gc_mutex)
				   - write_checkpoint
				    - block_operations
				     - f2fs_sync_inode_meta
				      - iput
				       - sb_start_intwrite
 - mutex_lock(&sbi->gc_mutex)

Fix this by altering sb_start_intwrite to sb_start_write_trylock.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Serialize data/node IOs by using fifo list instead of mutex lock,
it will help to enhance concurrency of f2fs, meanwhile keeping LFS
IO semantics.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This allows to freeze gc and discard threads.

Cc: stable@vger.kernel.org
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch add a new method get_ssr_cost to select
SSR segment more accurately.
Signed-off-by: NYunlei He <heyunlei@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Currently, if we do get_node_of_data before f2fs_lock_op, there may be dead lock
as follows, where process A would be in infinite loop, and B will NOT be awaked.

Process A(cp):            Process B:
f2fs_lock_all(sbi)
                        get_dnode_of_data <---- lock dn.node_page
flush_nodes             f2fs_lock_op

So, this patch adds f2fs_trylock_op to avoid f2fs_lock_op done by IPU.
Signed-off-by: NHou Pengyang <houpengyang@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Split DATA/NODE type bio cache according to different temperature,
so write IOs with the same temperature can be merged in corresponding
bio cache as much as possible, otherwise, different temperature write
IOs submitting into one bio cache will always cause split of bio.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Merged IO flow doesn't need to care about read IOs.

f2fs_submit_merged_bio -> f2fs_submit_merged_write
f2fs_submit_merged_bios -> f2fs_submit_merged_writes
f2fs_submit_merged_bio_cond -> f2fs_submit_merged_write_cond
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

By default, f2fs_gc returns -EINVAL in general error cases, e.g., no victim
was selected. However, the default errno may be overwritten in two cases:
gc_more and BG_GC -> FG_GC. We should return consistent errno in such cases.
Signed-off-by: NWeichao Guo <guoweichao@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>