For better read performance, we add a new function to support for merging
contiguous read as the one for write.

v1-->v2:
 o add declarations here as Gu Zheng suggested.
 o use new structure f2fs_bio_info introduced by Jaegeuk Kim.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Acked-by: NGu Zheng <guz.fnst@cn.fujitsu.com>

Signed-off-by: NGu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

Simplify write_orphan_inodes for better readable. Because we hold the
orphan_inode_mutex, so it's safe to use list_for_each_entry instead of
list_for_each_safe.
Signed-off-by: NGu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

Signed-off-by: NGu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

Signed-off-by: NGu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

Signed-off-by: NGu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

The f2fs has three bio types, NODE, DATA, and META, and manages some data
structures per each bio types.

The codes are a little bit messy, thus, this patch introduces a bio array
which groups individual data structures as follows.

struct f2fs_bio_info {
	struct bio *bio;		/* bios to merge */
	sector_t last_block_in_bio;	/* last block number */
	struct mutex io_mutex;		/* mutex for bio */
};

struct f2fs_sb_info {
	...
	struct f2fs_bio_info write_io[NR_PAGE_TYPE];	/* for write bios */
	...
};

The code changes from this new data structure are trivial.
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

The f2fs manages an extent cache to search a number of consecutive data blocks
very quickly.

However it conducts unnecessary cache operations if the file is highly
fragmented with no valid extent cache.

In such the case, we don't need to handle the extent cache, but just can disable
the cache facility.

Nevertheless, this patch gives one more chance to enable the extent cache.

For example,
1. create a file
2. write data sequentially which produces a large valid extent cache
3. update some data, resulting in a fragmented extent
4. if the fragmented extent is too small, then drop extent cache
5. close the file

6. open the file again
7. give another chance to make a new extent cache
8. write data sequentially again which creates another big extent cache.
...
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

This patch removes an unnecessary semaphore (i.e., sbi->bio_sem).
There is no reason to use the semaphore when f2fs submits read and write IOs.
Instead, let's use a write mutex and cover the sbi->bio[] by the lock.

Change log from v1:
 o split write_mutex suggested by Chao Yu

Chao described,
"All DATA/NODE/META bio buffers in superblock is protected by
'sbi->write_mutex', but each bio buffer area is independent, So we
should split write_mutex to three for DATA/NODE/META."
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

This patch introduces PAGE_TYPE_OF_BIO() and cleans up do_submit_bio() with it.
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

We should use f2fs_put_page to release page for uniform style of f2fs code.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

This patch adds a tracepoint for f2fs_issue_discard.
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

Change log from v1:
 o fix 32bit drops reported by Dan Carpenter

This patch adds f2fs_issue_discard() to clean up blkdev_issue_discard() flows.

Dan carpenter reported:
"block_t is a 32 bit type and sector_t is a 64 bit type.  The upper 32
bits of the sector_t are not used because the shift will wrap."
Bug-Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

If frequent small discards are issued to the device, the performance would
be degraded significantly.
So, this patch adds a sysfs entry to control the number of discards to be
issued during a checkpoint procedure.

By default, f2fs does not issue any small discards, which means max_discards
is zero.
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

This patch adds key functions to activate the small discard feature.

Note that this procedure is conducted during the checkpoint only.

In flush_sit_entries(), when a new dirty sit entry is flushed, f2fs calls
add_discard_addrs() which searches candidates to be discarded.
The candidates should be marked *invalidated* and also previous checkpoint
recognizes it as *valid*.

At the end of a checkpoint procedure, f2fs throws discards based on the
discard entry list.
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

This patch adds a slab cache entry for small discards.

Each entry consists of:

struct discard_entry {
	struct list_head list;	/* list head */
	block_t blkaddr;	/* block address to be discarded */
	int len;		/* # of consecutive blocks of the discard */
};
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

To find a zero bit using the result of OR operation between ckpt_valid_map
and cur_valid_map is more fast than find a zero bit in each bitmap.
Signed-off-by: NChangman Lee <cm224.lee@samsung.com>
[Jaegeuk Kim: adjust changed function name]
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

When f2fs_set_bit is used, in a byte MSB and LSB is reversed,
in that case we can use __find_rev_next_bit or __find_rev_next_zero_bit.
Signed-off-by: NChangman Lee <cm224.lee@samsung.com>
[Jaegeuk Kim: change the function names]
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

o Changes from v1
  Use find_next(_zero)_bit suggested by jg.kim

When f2fs issues discard command, if segment is contiguous,
let's issue more large segment to gather adjacent segments.

** blktrace **
179,1    0     5859    42.619023770   971  C   D 131072 + 2097152 [0]
179,1    0    33665   108.840475468   971  C   D 2228224 + 2494464 [0]
179,1    0    33671   109.131616427   971  C   D 14909440 + 344064 [0]
179,1    0    33677   109.137100677   971  C   D 15261696 + 4096 [0]
Signed-off-by: NChangman Lee <cm224.lee@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

If we failed to init&add kobject when fill_super, stats info and proc object of
f2fs will not be released.
We should free them before we finish fill_super.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

use genernal method supported by kernel

 o changes from v1
   If any waiter exists at end io, wake up it.
Signed-off-by: NChangman Lee <cm224.lee@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

A NULL point should avoid to be used in destroy_segment_manager after allocating
memory fail for f2fs_sm_info.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

In wait_on_node_pages_writeback we will test and clear error flag for all
pages in radix tree, but not necessary.
So we only do this for pages belong to the specified inode.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

Previously, f2fs_sync_file() waits for all the node blocks to be written.
But, we don't need to do that, but wait only the inode-related node blocks.

This patch adds wait_on_node_pages_writeback() in which waits inode-related
node blocks that are on writeback.
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

Previously, check_block_count check valid_map with bit data type in common
scenario that sit has all ones or zeros bitmap, it makes low mount performance.
So let's check the special bitmap with integer data type instead of the bit one.

v1-->v2:
 o use find_next_{zero_}bit_le for better performance and readable as Jaegeuk
   suggested.
 o use neat logogram in comment as Gu Zheng suggested.
 o search continuous ones or zeros for better performance when checking mixed
   bitmap.
Suggested-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>
Signed-off-by: NShu Tan <shu.tan@samsung.com>
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

npages_for_summary_flush uses (SUMMARY_SIZE + 1) as the size of a f2fs_summary
while its actual size is  SUMMARY_SIZE. So the result sometimes is bigger than
actual number by one, which causes checkpoint can't be written into disk
contiguously, and sometimes summary blocks can't be compacted like they should.
Besides, when writing summary blocks into pages, if remain space in a page
isn't big enough for one f2fs_summary, it will be left unused, current code
seems not to take it into account.
Signed-off-by: NFan Li <fanofcode.li@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

During xattr updating, free size should be corrected to remainder free size
+ old entry size.
It can avoid ENOSPC error when we update old entry with the same size new
entry at fully filled xattr.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

If you want to remove unnecessary BUG_ONs, you can just turn off F2FS_CHECK_FS
in your kernel config.
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

This config will support an option to remove so many BUG_ONs that degrade
the performance potentially.
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

The deadlock is found through the following scenario.

sys_mkdir()
 -> f2fs_add_link()
  -> __f2fs_add_link()
   -> init_inode_metadata()
     : lock_page(inode);
    -> f2fs_init_acl()
     -> f2fs_set_acl()
      -> f2fs_setxattr(..., NULL)
       : This NULL page incurs a deadlock at update_inode_page().

So, likewise f2fs_init_security(), this patch adds a parameter to transfer the
locked inode page to f2fs_setxattr().

Found by Linux File System Verification project (linuxtesting.org).
Reported-by: NAlexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

This patch cleans up a couple of acl codes.
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

Only one dirty type is set in __locate_dirty_segment and we can know
dirty type of segment. So we don't need to check other dirty types.
Signed-off-by: NChangman Lee <cm224.lee@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

This patch adds a tracepoint for f2fs_vm_page_mkwrite.
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

This patch adds a tracepoint for set_page_dirty.
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

Previously, set_page_dirty is called every time after writting one summary info
into compacted summary page,
To avoid redundant set_page_dirty, we only call set_page_dirty before release
page.
Signed-off-by: NYu Chao <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

This patch adds a control method in sysfs to reclaim prefree segments.
Signed-off-by: NChangman Lee <cm224.lee@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

This patch merges some background jobs into this new function.
Signed-off-by: NChangman Lee <cm224.lee@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

Previously, f2fs postpones reclaiming prefree segments into free segments
as much as possible.
However, if user writes and deletes a bunch of data without any sync or fsync
calls, some flash storages can suffer from garbage collections.

So, this patch adds the reclaiming codes to f2fs_write_node_pages and background
GC thread.

If there are a lot of prefree segments, let's do checkpoint so that f2fs
submits discard commands for the prefree regions to the flash storage.
Signed-off-by: NChangman Lee <cm224.lee@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

Signed-off-by: NHaicheng Li <haicheng.li@linux.intel.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

This patch cleans up improper definitions that update some status information.
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>