truncate_data_blocks_range can do in batches truncation which makes all
changes in dnode page content, dnode page status, extent cache, block
count updating together.

But previously, truncate_hole() always truncates one block in dnode page
at a time by invoking truncate_data_blocks_range(,1), which make thing
slow.

This patch changes truncate_hole() to do in batches truncation for all
target blocks in one direct node inside truncate_data_blocks_range, which
can make our punch hole operation in ->fallocate more efficent.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Fix 2 potential problems:
1. when largest extent needs to be invalidated, it will be reset in
   __drop_largest_extent, which makes __is_extent_same after always
   return false, and largest extent unchanged. Now we update it properly.

2. when extent is split and the latter part remains in tree, next_en
   should be the latter part instead of next extent of original extent.
   It will cause merge failure if there is in-place update, although
   there is not, I think this fix will still makes codes less ambiguous.

This patch also simplifies codes of invalidating extents, and optimizes the
procedues that split extent into two.
There are a few modifications after last patch:
1. prev_en now is updated properly.
2. more codes and branches are simplified.
Signed-off-by: NFan li <fanofcode.li@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

now we update extent by range, fofs may not be on the largest
extent if the new extent overlaps with it. so add a new function
to drop largest extent properly.
Signed-off-by: NFan li <fanofcode.li@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch avoids to produce new checkpoint blocks before the previous meta
pages were written completely.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

We got dentry pages from high_mem, and its address space directly goes into the
decryption path via f2fs_fname_disk_to_usr.
But, sg_init_one assumes the address is not from high_mem, so we can get this
panic since it doesn't call kmap_high but kunmap_high is triggered at the end.

kernel BUG at ../../../../../../kernel/mm/highmem.c:290!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
...
 (kunmap_high+0xb0/0xb8) from [<c0114534>] (__kunmap_atomic+0xa0/0xa4)
 (__kunmap_atomic+0xa0/0xa4) from [<c035f028>] (blkcipher_walk_done+0x128/0x1ec)
 (blkcipher_walk_done+0x128/0x1ec) from [<c0366c24>] (crypto_cbc_decrypt+0xc0/0x170)
 (crypto_cbc_decrypt+0xc0/0x170) from [<c0367148>] (crypto_cts_decrypt+0xc0/0x114)
 (crypto_cts_decrypt+0xc0/0x114) from [<c035ea98>] (async_decrypt+0x40/0x48)
 (async_decrypt+0x40/0x48) from [<c032ca34>] (f2fs_fname_disk_to_usr+0x124/0x304)
 (f2fs_fname_disk_to_usr+0x124/0x304) from [<c03056fc>] (f2fs_fill_dentries+0xac/0x188)
 (f2fs_fill_dentries+0xac/0x188) from [<c03059c8>] (f2fs_readdir+0x1f0/0x300)
 (f2fs_readdir+0x1f0/0x300) from [<c0218054>] (vfs_readdir+0x90/0xb4)
 (vfs_readdir+0x90/0xb4) from [<c0218418>] (SyS_getdents64+0x64/0xcc)
 (SyS_getdents64+0x64/0xcc) from [<c0105ba0>] (ret_fast_syscall+0x0/0x30)

Cc: <stable@vger.kernel.org>
Reviewed-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>

This function should be static.
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>

When shrinking extent cache, we have two steps in the flow:
1) shrink objects which are unreferenced by inodes;
2) shrink objects from LRU list of extent cache.

In step 1, if we haven't shrunk enough number of objects, we will try
step 2, but before that we didn't update the searching position which
may point to last inode index in global extent tree, result in failing
to shrink objects by traversing the all inodes' extent tree.

In this patch, we reset searching position to beginning of global extent
tree for fixing.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch changes to verify file type early in f2fs_fallocate for
cleanup, meanwhile this also fixes to add missing verification for
expand_inode_data.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

As comment says, we don't need to call f2fs_lock_op in write_inode to prevent
from producing dirty node pages all the time.
That happens only when there is not enough free sections and we can avoid that
by calling balance_fs in prior to that.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This number is referenced by checkpoint under node_write lock.
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This fixes the incorrect return statement at the end of the function
f2fs_ioc_release_volatile_write's body for returning zero as this is
incorrect due to the function call before this return statement to
the function punch_hole being able to fail and we should return this
function's return fail directly in order to signal to callers of the
function f2fs_ioc_release_volatile if a failure arises with this call
to punch_hole fails.
Signed-off-by: NNicholas Krause <xerofoify@gmail.com>
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Rename trace_f2fs_update_extent_tree to trace_f2fs_update_extent_tree_range,
then expand and enable it to trace in batches extent info updates.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

upset segment_info like this:

276000|161 0|0   4|70  3|0   3|0   0|0   0|91  4|0   4|232 4|39
276104|0   4|0   4|1   4|0   4|0   4|280 4|0   4|42  4|262 4|38
276204|179 4|89  4|39  4|24  4|0   4|96  4|3   4|428 4|0   4|118
276304|112 4|97  4|0   4|0   4|0   4|68  4|0   4|0   4|86  4|138
276404|0   4|0   0|166 5|39  4|101 0|111
Signed-off-by: NYunlei He <heyunlei@huawei.com>
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

If extent cache is disable, we will encounter oops when triggering direct
IO as below:

BUG: unable to handle kernel NULL pointer dereference at 0000000c
IP: [<f0b9c61e>] f2fs_drop_largest_extent+0xe/0x30 [f2fs]
*pdpt = 000000002bb9a001 *pde = 0000000000000000
Oops: 0000 [#1] SMP
Modules linked in: f2fs(O) fuse bnep rfcomm bluetooth nfsd dm_crypt nfs_acl auth_rpcgss oid_registry nfs binfmt_misc fscache lockd
sunrpc grace snd_intel8x0 snd_ac97_codec ac97_bus snd_pcm snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq snd_timer
snd_seq_device snd soundcore joydev psmouse hid_generic i2c_piix4 serio_raw ppdev mac_hid parport_pc lp parport ext4 jbd2 mbcache
usbhid hid e1000
CPU: 3 PID: 3608 Comm: dd Tainted: G           O    4.2.0-rc4 #12
Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
task: ef161600 ti: ebd5e000 task.ti: ebd5e000
EIP: 0060:[<f0b9c61e>] EFLAGS: 00010202 CPU: 3
EIP is at f2fs_drop_largest_extent+0xe/0x30 [f2fs]
EAX: 00000000 EBX: ddebc000 ECX: 00000000 EDX: 00000000
ESI: ebd5fdf8 EDI: 00000000 EBP: ebd5fd58 ESP: ebd5fd58
 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
CR0: 80050033 CR2: 0000000c CR3: 2c24ee40 CR4: 000006f0
Stack:
 ebd5fda4 f0b8c005 00000000 00000001 00000000 f0b8c430 c816cd68 ddebc000
 ddebc088 00001000 00000555 00000555 ffffffff c160bb00 00055501 00000000
 00000000 00000100 00000000 ebd5fe20 f0b8c430 00000046 ef161600 00001000
Call Trace:
 [<f0b8c005>] __allocate_data_block+0x1a5/0x260 [f2fs]
 [<f0b8c430>] ? f2fs_direct_IO+0x370/0x440 [f2fs]
 [<c160bb00>] ? down_read+0x30/0x50
 [<f0b8c430>] f2fs_direct_IO+0x370/0x440 [f2fs]
 [<c113e115>] generic_file_direct_write+0xa5/0x260
 [<c10b53f8>] ? current_fs_time+0x18/0x50
 [<c113e38b>] __generic_file_write_iter+0xbb/0x210
 [<c113e50f>] ? generic_file_write_iter+0x2f/0x320
 [<c113e63c>] generic_file_write_iter+0x15c/0x320
 [<f0b77f29>] f2fs_file_write_iter+0x39/0x80 [f2fs]
 [<c11984d9>] __vfs_write+0xa9/0xe0
 [<c1199227>] vfs_write+0x97/0x180
 [<c119955b>] SyS_write+0x5b/0xd0
 [<c160dcd0>] sysenter_do_call+0x12/0x12
Code: 10 8b 50 1c 89 53 14 eb ca 8d 74 26 00 85 f6 74 86 eb a6 0f 0b 90 8d b4 26 00 00 00 00 55 89 e5 3e 8d 74 26 00 8b 80 d4 02 00
00 <8b> 48 0c 39 d1 77 0e 03 48 14 39 ca 73 07 c7 40 14 00 00 00 00
EIP: [<f0b9c61e>] f2fs_drop_largest_extent+0xe/0x30 [f2fs] SS:ESP 0068:ebd5fd58
CR2: 000000000000000c
---[ end trace a38c07026a1afffd ]---

This is because when extent cache is disable, extent_tree pointer in struct
f2fs_inode_info should be NULL, but in f2fs_drop_largest_extent we access
this NULL pointer directly without checking state of extent cache, then,
the oops occurs. Let's fix it by checking state of extent cache before
accessing.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch introduce a new helper f2fs_update_extent_tree_range which can
do extent mapping update at a specified range.

The main idea is:
1) punch all mapping info in extent node(s) which are at a specified range;
2) try to merge new extent mapping with adjacent node, or failing that,
   insert the mapping into extent tree as a new node.

In order to see the benefit, I add a function for stating time stamping
count as below:

uint64_t rdtsc(void)
{
	uint32_t lo, hi;
	__asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
	return (uint64_t)hi << 32 | lo;
}

My test environment is: ubuntu, intel i7-3770, 16G memory, 256g micron ssd.

truncation path:	update extent cache from truncate_data_blocks_range
non-truncataion path:	update extent cache from other paths
total:			all update paths

a) Removing 128MB file which has one extent node mapping whole range of
file:
1. dd if=/dev/zero of=/mnt/f2fs/128M bs=1M count=128
2. sync
3. rm /mnt/f2fs/128M

Before:
		total		count		average
truncation:	7651022		32768		233.49

Patched:
		total		count		average
truncation:	3321		33		100.64

b) fsstress:
fsstress -d /mnt/f2fs -l 5 -n 100 -p 20
Test times:		5 times.

Before:
		total		count		average
truncation:	5812480.6	20911.6		277.95
non-truncation:	7783845.6	13440.8		579.12
total:		13596326.2	34352.4		395.79

Patched:
		total		count		average
truncation:	1281283.0	3041.6		421.25
non-truncation:	7355844.4	13662.8		538.38
total:		8637127.4	16704.4		517.06

1) For the updates in truncation path:
 - we can see updating in batches leads total tsc and update count reducing
   explicitly;
 - besides, for a single batched updating, punching multiple extent nodes
   in a loop, result in executing more operations, so our average tsc
   increase intensively.
2) For the updates in non-truncation path:
 - there is a little improvement, that is because for the scenario that we
   just need to update in the head or tail of extent node, new interface
   optimize to update info in extent node directly, rather than removing
   original extent node for updating and then inserting that updated one
   into cache as new node.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

In following call stack, if unfortunately we lose all chances to truncate
inode page in remove_inode_page, eventually we will add the nid allocated
previously into free nid cache, this nid is with NID_NEW status and with
NEW_ADDR in its blkaddr pointer:

 - f2fs_create
  - f2fs_add_link
   - __f2fs_add_link
    - init_inode_metadata
     - new_inode_page
      - new_node_page
       - set_node_addr(, NEW_ADDR)
     - f2fs_init_acl   failed
     - remove_inode_page  failed
  - handle_failed_inode
   - remove_inode_page  failed
   - iput
    - f2fs_evict_inode
     - remove_inode_page  failed
     - alloc_nid_failed   cache a nid with valid blkaddr: NEW_ADDR

This may not only cause resource leak of previous inode, but also may cause
incorrect use of the previous blkaddr which is located in NO.nid node entry
when this nid is reused by others.

This patch tries to add this inode to orphan list if we fail to truncate
inode, so that we can obtain a second chance to release it in orphan
recovery flow.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch fixes to return error number of f2fs_truncate, so that we
can handle the error correctly in callers.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

When converting inline dentry, we will zero out target dentry page before
duplicating data of inline dentry into target page, it become overhead
since inline dentry size is not small.

So this patch tries to remove unneeded initializing in the space of target
dentry page.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

According to commit 5f16f322 ("ext4: atomically set inode->i_flags in
ext4_set_inode_flags()").
Signed-off-by: NZhang Zhen <zhenzhang.zhang@huawei.com>
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

If we release the lock in list_for_each_entry_safe, we can lose the tmp
pointer by alloc_nid.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

__GFP_NOFAIL can avoid retrying the whole path of kmem_cache_alloc and
bio_alloc.
And, it also fixes the use cases of GFP_ATOMIC correctly.
Suggested-by: NChao Yu <chao2.yu@samsung.com>
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

In __lookup_extent_tree_ret we will not try to find neighbor nodes if
we find the target node, in this condition, we will lost the chance to
merge the new mapping with exist extent node later.

So our extent cache of inode will be fragmented after overwrite exist
file, we can see the number of extent node increases intensively in
following test case:

dd if=/dev/zero of=/mnt/f2fs/4m bs=4K count=1024

Extent Cache:
  - Hit Count: L1-1:0 L1-2:0 L2:0
  - Hit Ratio: 0% (0 / 3072)
  - Inner Struct Count: tree: 1, node: 1

dd if=/dev/zero of=/mnt/f2fs/4m bs=4K count=1024 conv=notrunc

Extent Cache:
  - Hit Count: L1-1:2048 L1-2:0 L2:0
  - Hit Ratio: 33% (2048 / 6144)
  - Inner Struct Count: tree: 1, node: 961

This patch fixes to lookup neighbors of target node for further
merging.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch splits __insert_extent_tree_ret into __try_merge_extent_node &
__insert_extent_tree for code readability.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

After commit 0f825ee6 ("f2fs: add new interfaces for extent tree"),
f2fs_init_extent_tree becomes the only caller of __insert_extent_tree, and
in f2fs_init_extent_tree, we will only insert extent node in an empty tree,
so __try_{back,front}_merge in __insert_extent_tree will never be called.

This patch removes these dead codes, besides, rename __insert_extent_tree
to __init_extent_tree for readability.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch alters to replace total hit stat with rbtree hit stat,
and then adjust showing of extent cache stat:

Hit Count:
L1-1: for largest node hit count;
L1-2: for last cached node hit count;
L2: for extent node hit after lookuping in rbtree.

Hit Ratio:
ratio (hit count / total lookup count)

Inner Struct Count:
tree count, node count.

Before:
Extent Hit Ratio: 0 / 2

Extent Tree Count: 3

Extent Node Count: 2

Patched:
Exten Cacache:
  - Hit Count: L1-1:4871 L1-2:2074 L2:208
  - Hit Ratio: 1% (7153 / 550751)
  - Inner Struct Count: tree: 26560, node: 11824
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch adds to stat the hit count of largest/cached node for showing
in debugfs.
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>

In f2fs_lookup_extent_tree, et->cached_en was read and updated with only
read lock held,
it could cause __lookup_extent_tree within return entirely wrong
extent_node, if other
thread update et->cached_en just before __lookup_extent_tree return.

However, there are two things about this patch that need to be noticed:
1. It does no good to arrange the order of concurrent read/write, the result
would still
be random in such case.
2. It's built on this assumption: the mix up of reads and writes on a single
pointer would
not make the pointer partially wrong at any time. Please let me know if I'm
wrong, thx.
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>

Fix typo.
Signed-off-by: NJunesung Lee <junesoung412@gmail.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch adds a routine which checks the block address of newly allocated nid.
If an nid has already allocated by other thread due to subtle data races, it
will result in filesystem corruption.
So, it needs to check whether its block address was already allocated or not
in prior to nid allocation as the last chance.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

We should not call unlock_new_inode when insert_inode_locked failed.
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

If FG_GC failed to reclaim one section, let's retry with another section
from the start, since we can get anoterh good candidate.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Previously, update_inode_page is not called under f2fs_lock_op.
Instead we should call with f2fs_write_inode.
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

If we can reuse nids as many as possible, we can mitigate producing obsolete
node pages in the page cache.
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

If node blocks were already moved, we don't need to move them again.
Reviewed-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>

This patch increases the number of maximum hard links for one file.
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

We should avoid needless checkpoints when there is no dirty and prefree segment.
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>