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Subject[PATCH 3.16 054/136] f2fs: remove redundant lines in allocate_data_block
3.16.54-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Dongho Sim <dh.sim@samsung.com>

commit 33be828ada7274ebcade2001f16e5b4e33a4636e upstream.

There are redundant lines in allocate_data_block.

In this function, we call refresh_sit_entry with old seg and old curseg.
After that, we call locate_dirty_segment with old curseg.

But, the new address is always allocated from old curseg and
we call locate_dirty_segment with old curseg in refresh_sit_entry.
So, we do not need to call locate_dirty_segment with old curseg again.

We've discussed like below:

Jaegeuk said:
"When considering SSR, we need to take care of the following scenario.
- old segno : X
- new address : Z
- old curseg : Y
This means, a new block is supposed to be written to Z from X.
And Z is newly allocated in the same path from Y.

In that case, we should trigger locate_dirty_segment for Y, since
it was a current_segment and can be dirty owing to SSR.
But that was not included in the dirty list."

Changman said:
"We already choosed old curseg(Y) and then we allocate new address(Z) from old
curseg(Y). After that we call refresh_sit_entry(old address, new address).
In the funcation, we call locate_dirty_segment with old seg and old curseg.
So calling locate_dirty_segment after refresh_sit_entry again is redundant."

Jaegeuk said:
"Right. The new address is always allocated from old_curseg."

Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Dongho Sim <dh.sim@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
fs/f2fs/segment.c | 3 ---
1 file changed, 3 deletions(-)

--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -969,14 +969,12 @@ void allocate_data_block(struct f2fs_sb_
{
struct sit_info *sit_i = SIT_I(sbi);
struct curseg_info *curseg;
- unsigned int old_cursegno;

curseg = CURSEG_I(sbi, type);

mutex_lock(&curseg->curseg_mutex);

*new_blkaddr = NEXT_FREE_BLKADDR(sbi, curseg);
- old_cursegno = curseg->segno;

/*
* __add_sum_entry should be resided under the curseg_mutex
@@ -997,7 +995,6 @@ void allocate_data_block(struct f2fs_sb_
* since SSR needs latest valid block information.
*/
refresh_sit_entry(sbi, old_blkaddr, *new_blkaddr);
- locate_dirty_segment(sbi, old_cursegno);

mutex_unlock(&sit_i->sentry_lock);

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