Previous selected segment may become free after write_checkpoint,
if we do garbage collect on this segment, and then new_curseg happen
to reuse it, it may cause f2fs_bug_on as below.

	panic+0x154/0x29c
	do_garbage_collect+0x15c/0xaf4
	f2fs_gc+0x2dc/0x444
	f2fs_balance_fs.part.22+0xcc/0x14c
	f2fs_balance_fs+0x28/0x34
	f2fs_map_blocks+0x5ec/0x790
	f2fs_preallocate_blocks+0xe0/0x100
	f2fs_file_write_iter+0x64/0x11c
	new_sync_write+0xac/0x11c
	vfs_write+0x144/0x1e4
	SyS_write+0x60/0xc0

Here, maybe we check sit and ssa type during reset_curseg. So, we check
segment is stale or not, and select a new victim to avoid this.
Signed-off-by: Yunlei He <heyunlei@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

It's enough to show BUG or WARN by f2fs_bug_on for error case.
Then, we don't need to remain corrupted filesystem.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

When fs utilization is almost full, f2fs_sync_file should do checkpoint if
there is not enough space for roll-forward later. (i.e. space_for_roll_forward)
So, currently we have no lock for sbi->alloc_valid_block_count, resulting in
race condition.

In rare case, we can get -ENOSPC when doing roll-forward which triggers

	if (is_valid_blkaddr(sbi, dest, META_POR)) {
		if (src == NULL_ADDR) {
			err = reserve_new_block(&dn);
			f2fs_bug_on(sbi, err);
			...
		}
		...
	}
in do_recover_data.

So, this patch avoids that situation in advance.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This patch implements moving a range of data blocks from source file to
destination file.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This patch fixes to report the right error number of f2fs_find_entry to
its caller.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

We need to avoid ENOMEM due to unexpected long length.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

The default value of idle interval is 2 mins, but for most time when
screen shutdown, there are still operations during the 2 mins interval,
and gc's sleep time is about 30 secs to 60 secs, so there is almost no
chance for GC thread to do garbage collecting.

Set default value of idle interval value from 2 mins to 5 secs for
fixing.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This patch reverts 19a5f5e2 (f2fs: drop any block plugging),
and adds blk_plug in write paths additionally.

The main reason is that blk_start_plug can be used to wake up from low-power
mode before submitting further bios.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Datas in file can be operated by GC and DIO simultaneously, so we will
face race case as below:

For write case:
Thread A				Thread B
- generic_file_direct_write
 - invalidate_inode_pages2_range
 - f2fs_direct_IO
  - do_blockdev_direct_IO
   - do_direct_IO
    - get_more_blocks
					- f2fs_gc
					 - do_garbage_collect
					  - gc_data_segment
					   - move_data_page
					    - do_write_data_page
					    migrate data block to new block address
   - dio_bio_submit
   update user data to old block address

For read case:
Thread A                                Thread B
- generic_file_direct_write
 - invalidate_inode_pages2_range
 - f2fs_direct_IO
  - do_blockdev_direct_IO
   - do_direct_IO
    - get_more_blocks
					- f2fs_balance_fs
					 - f2fs_gc
					  - do_garbage_collect
					   - gc_data_segment
					    - move_data_page
					     - do_write_data_page
					     migrate data block to new block address
					  - write_checkpoint
					   - do_checkpoint
					    - clear_prefree_segments
					     - f2fs_issue_discard
                                             discard old block adress
   - dio_bio_submit
   update user buffer from obsolete block address

In order to fix this, for one file, we should let DIO and GC getting exclusion
against with each other.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

In 1TB storage, we need to admit 22841 prefree segments, which can consume
too much segments.
This patch sets 8GB in max. prefree segments in that case.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This reduces the elapsed time to do xfstests/generic/017.

Before: 458 s
After:  390 s
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This reduces the elapsed time to do xfstests/generic/017.

Before: 715 s
After:  458 s
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This is to fix wrong error pointer handling flow reported by Dan.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Let's check inode's dirtiness before calling mark_inode_dirty.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

We don't need to do i_size_write under page lock.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

With below test steps, f2fs will issue redundant discard when doing fstrim,
the reason is that we issue discards for both prefree segments and
consecutive freed region user wants to trim, part regions they covered are
overlapped, here, we change to do not to issue any discards for prefree
segments in trimmed range.

1. mount -t f2fs -o discard /dev/zram0 /mnt/f2fs
2. fstrim -o 0 -l 3221225472 -m 2097152 -v /mnt/f2fs/
3. dd if=/dev/zero  of=/mnt/f2fs/a bs=2M count=1
4. dd if=/dev/zero  of=/mnt/f2fs/b bs=1M count=1
5. sync
6. rm /mnt/f2fs/a /mnt/f2fs/b
7. fstrim -o 0 -l 3221225472 -m 2097152 -v /mnt/f2fs/

Before:
<...>-5428  [001] ...1  9511.052125: f2fs_issue_discard: dev = (251,0), blkstart = 0x2200, blklen = 0x200
<...>-5428  [001] ...1  9511.052787: f2fs_issue_discard: dev = (251,0), blkstart = 0x2200, blklen = 0x300

After:
<...>-6764  [000] ...1  9720.382504: f2fs_issue_discard: dev = (251,0), blkstart = 0x2200, blklen = 0x300
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This patch skip discard block range smaller than trim_minlen,
and can not be merged by neighbour
Signed-off-by: Yunlei He <heyunlei@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

As manual described, f_bfree indicates total free blocks in fs, in f2fs, it
includes two parts: visible free blocks and over-provision blocks. This
patch corrrects the calculation.

fsblkcnt_t   f_bfree;   /* free blocks in fs */
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This patch replaces rw_semaphore with percpu_rw_semaphore for:
sbi->cp_rwsem
nm_i->nat_tree_lock
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

If the node page is up-to-date, it should be alive.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This patch shrinks the critical region in spin_lock.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

SetPageUptodate() issues memory barrier, resulting in performance degrdation.
Let's avoid that.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This patch adds f2fs_set_page_dirty_nobuffer() copied from __set_page_dirty_buffer.
When appending 4KB blocks in f2fs on pmem with multiple cores, this improves the
overall performance.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

When base_addr is NULL, there is no need to call kzfree,
it should return -ENOMEM directly. Additionally, it is
better to initialize variable 'error' with 0.
Signed-off-by: Tiezhu Yang <kernelpatch@126.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This patch adds 'nodiscard' mount option.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

If we fail to move data page during foreground GC, we should give another
chance to writeback that page which was set dirty previously by writer.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

In procedure of synchonized read, after sending out the read request, reader
will try to lock the page for waiting device to finish the read jobs and
unlock the page, but meanwhile, truncater will race with reader, so after
reader get lock of the page, it should check page's mapping to detect
whether someone has truncated the page in advance, then reader has the
chance to do the retry if truncation was done, otherwise read can be failed
due to previous condition check.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

For encrypted inode, if user overwrites data of the inode, f2fs will read
encrypted data into page cache, and then do the decryption.

However reader can race with overwriter, and it will see encrypted data
which has not been decrypted by overwriter yet. Fix it by moving decrypting
work to background and keep page non-uptodated until data is decrypted.

Thread A				Thread B
- f2fs_file_write_iter
 - __generic_file_write_iter
  - generic_perform_write
   - f2fs_write_begin
    - f2fs_submit_page_bio
					- generic_file_read_iter
					 - do_generic_file_read
					  - lock_page_killable
					  - unlock_page
					  - copy_page_to_iter
					  hit the encrypted data in updated page
    - lock_page
    - fscrypt_decrypt_page
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

The f2fs_map_blocks is very related to the performance, so let's avoid any
latency to read ahead node pages.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Let's keep more node/meta pages in run time.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

The readahead nat pages are more likely to be reclaimed quickly, so it'd better
to gather more free nids in advance.

And, let's keep some free nids as much as possible.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

If mkfs.f2fs gives a feature flag for host-managed SMR, we can set mode=lfs
by default.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Let's store orphan inode pages right away.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

If there is no dentry, we can report its error correctly.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

If dotdot directory is corrupted, its slot may be ocupied by another
file. In this case, dentry[1] is not the parent directory. Rename and
cross-rename will update the inode in dentry[1] incorrectly.   This
patch finds dotdot dentry by name.
Signed-off-by: Sheng Yong <shengyong1@huawei.com>
[Jaegeuk Kim: remove wron bug_on]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

mkdir                        sync_dirty_inode
 - init_inode_metadata
   - lock_page(node)
   - make_empty_dir
                             - filemap_fdatawrite()
                              - do_writepages
                              - lock_page(data)
                              - write_page(data)
                               - lock_page(node)
   - f2fs_init_acl
    - error
   - truncate_inode_pages
    - lock_page(data)

So, we don't need to truncate data pages in this error case, which will
be done by f2fs_evict_inode.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

This mount option is to enable original log-structured filesystem forcefully.
So, there should be no random writes for main area.

Especially, this supports host-managed SMR device.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

If a segment in a section is clean or prefreed, we don't need to get its summary
and do gc.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

In f2fs, we don't need to keep block plugging for NODE and DATA writes, since
we already merged bios as much as possible.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

There is a data race between allocate_data_block() and f2fs_sbumit_page_mbio(),
which incur unnecessary reversed bio submission.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>