Re: (2) [f2fs-dev] [PATCH] Revert "f2fs: use flush command instead of FUA for zoned device"

From: Chao Yu
Date: Thu Jun 20 2024 - 03:12:52 EST


On 2024/6/20 13:56, Daejun Park wrote:
Hi Chao,

Jaegeuk,

Quoted commit message from commit c550e25bca66 ("f2fs: use flush command
instead of FUA for zoned device")
"
The block layer for zoned disk can reorder the FUA'ed IOs. Let's use flush
command to keep the write order.
"

It seems mq-deadline use fifo queue and make queue depth of zone device
as 1 to IO order, so why FUA'ed write node IOs can be reordered by block
layer?

While other writes are aligned by the mq-deadline, write with FUA is not passed
to the scheduler but handled at the block layer.

Hi Daejun,

IIUC, do you mean write w/ FUA may be handled directly in below path?

- blk_mq_submit_bio
- op_is_flush && blk_insert_flush

Thanks,


Thanks,
Daejun


Thanks,

On 2024/6/14 8:48, Wenjie Cheng wrote:
This reverts commit c550e25bca660ed2554cbb48d32b82d0bb98e4b1.

Commit c550e25bca660ed2554cbb48d32b82d0bb98e4b1 ("f2fs: use flush
command instead of FUA for zoned device") used additional flush
command to keep write order.

Since Commit dd291d77cc90eb6a86e9860ba8e6e38eebd57d12 ("block:
Introduce zone write plugging") has enabled the block layer to
handle this order issue, there is no need to use flush command.

Signed-off-by: Wenjie Cheng <cwjhust@xxxxxxxxx>
---
  fs/f2fs/file.c 3 +--
  fs/f2fs/node.c 2 +-
  2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index eae2e7908072..f08e6208e183 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -372,8 +372,7 @@ static int f2fs_do_sync_file(struct file *file, loff_t start, loff_t end,
           f2fs_remove_ino_entry(sbi, ino, APPEND_INO);
           clear_inode_flag(inode, FI_APPEND_WRITE);
  flush_out:
-        if ((!atomic && F2FS_OPTION(sbi).fsync_mode != FSYNC_MODE_NOBARRIER)
-            (atomic && !test_opt(sbi, NOBARRIER) && f2fs_sb_has_blkzoned(sbi)))
+        if (!atomic && F2FS_OPTION(sbi).fsync_mode != FSYNC_MODE_NOBARRIER)
                   ret = f2fs_issue_flush(sbi, inode->i_ino);
           if (!ret) {
                   f2fs_remove_ino_entry(sbi, ino, UPDATE_INO);
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 144f9f966690..c45d341dcf6e 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1631,7 +1631,7 @@ static int __write_node_page(struct page *page, bool atomic, bool *submitted,
                   goto redirty_out;
           }
-        if (atomic && !test_opt(sbi, NOBARRIER) && !f2fs_sb_has_blkzoned(sbi))
+        if (atomic && !test_opt(sbi, NOBARRIER))
                   fio.op_flags = REQ_PREFLUSH REQ_FUA;
           /* should add to global list before clearing PAGECACHE status */