After applying Harshad's patch series "ext4 fast commit API cleanup" ,
this issue has been fixed.
So , please ignore this patch.

Thank,
Xin Yin

On Thu, Dec 23, 2021 at 10:44 AM harshad shirwadkar [off-list ref] wrote:

Once the patch series "ext4 fast commit API cleanup" gets merged in
(https://patchwork.ozlabs.org/project/linux-ext4/list/?series=277672),
this patch won't be required anymore. So, I'll undo my review in favor
of merging the API cleanup patch series first.

- Harshad

On Fri, Dec 17, 2021 at 12:17 PM harshad shirwadkar
[off-list ref] wrote:

quoted

Thanks for the patch Xin, it looks good to me. I think there are a few
other places where we are not stopping the transaction before calling
commit. I'm trying to find them out.

Reviewed-by: Harshad Shirwadkar <redacted>

On Thu, Dec 16, 2021 at 12:04 AM Xin Yin [off-list ref] wrote:

quoted

If open a file with O_SYNC, and call fallocate with mode=0.when using
fast commit, will cause the process to hang.

During the fast_commit procedure, it will wait for inode update done.
call ext4_fc_stop_update() before ext4_fc_commit() to mark inode
complete update.

Signed-off-by: Xin Yin <redacted>
---
 fs/ext4/extents.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 4108896d471b..92db33887b6c 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c

@@ -4707,8 +4707,12 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
                goto out;

        if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
+               ext4_fc_stop_update(inode);
                ret = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
                                        EXT4_I(inode)->i_sync_tid);
+               inode_unlock(inode);
+               trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
+               return ret;
        }
 out:
        inode_unlock(inode);
--

2.20.1