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SubjectRe: [PATCH] f2fs: add a wait step when submit bio with {READ,WRITE}_SYNC
Hi Kim,

On 07/30/2013 08:29 PM, Jaegeuk Kim wrote:

> Hi Gu,
>
> The original read flow was to avoid redandunt lock/unlock_page() calls.

Right, this can gain better read performance. But is the wait step after
submitting bio with READ_SYNC needless too?

> And we should not wait for WRITE_SYNC, since it is just for write
> priority, not for synchronization of the file system.

Got it, thanks for your explanation.:)

Best regards,
Gu

> Thanks,
>
> 2013-07-30 (화), 18:06 +0800, Gu Zheng:
>> When we submit bio with READ_SYNC or WRITE_SYNC, we need to wait a
>> moment for the io completion, current codes only find_data_page() follows the
>> rule, other places missing this step, so add it.
>>
>> Further more, moving the PageUptodate check into f2fs_readpage() to clean up
>> the codes.
>>
>> Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
>> ---
>> fs/f2fs/checkpoint.c | 1 -
>> fs/f2fs/data.c | 39 +++++++++++++++++----------------------
>> fs/f2fs/node.c | 1 -
>> fs/f2fs/recovery.c | 2 --
>> fs/f2fs/segment.c | 2 +-
>> 5 files changed, 18 insertions(+), 27 deletions(-)
>>
>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
>> index fe91773..e376a42 100644
>> --- a/fs/f2fs/checkpoint.c
>> +++ b/fs/f2fs/checkpoint.c
>> @@ -64,7 +64,6 @@ repeat:
>> if (f2fs_readpage(sbi, page, index, READ_SYNC))
>> goto repeat;
>>
>> - lock_page(page);
>> if (page->mapping != mapping) {
>> f2fs_put_page(page, 1);
>> goto repeat;
>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>> index 19cd7c6..b048936 100644
>> --- a/fs/f2fs/data.c
>> +++ b/fs/f2fs/data.c
>> @@ -216,13 +216,11 @@ struct page *find_data_page(struct inode *inode, pgoff_t index, bool sync)
>>
>> err = f2fs_readpage(sbi, page, dn.data_blkaddr,
>> sync ? READ_SYNC : READA);
>> - if (sync) {
>> - wait_on_page_locked(page);
>> - if (!PageUptodate(page)) {
>> - f2fs_put_page(page, 0);
>> - return ERR_PTR(-EIO);
>> - }
>> - }
>> + if (err)
>> + return ERR_PTR(err);
>> +
>> + if (sync)
>> + unlock_page(page);
>> return page;
>> }
>>
>> @@ -267,11 +265,6 @@ repeat:
>> if (err)
>> return ERR_PTR(err);
>>
>> - lock_page(page);
>> - if (!PageUptodate(page)) {
>> - f2fs_put_page(page, 1);
>> - return ERR_PTR(-EIO);
>> - }
>> if (page->mapping != mapping) {
>> f2fs_put_page(page, 1);
>> goto repeat;
>> @@ -325,11 +318,7 @@ repeat:
>> err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
>> if (err)
>> return ERR_PTR(err);
>> - lock_page(page);
>> - if (!PageUptodate(page)) {
>> - f2fs_put_page(page, 1);
>> - return ERR_PTR(-EIO);
>> - }
>> +
>> if (page->mapping != mapping) {
>> f2fs_put_page(page, 1);
>> goto repeat;
>> @@ -399,6 +388,16 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page,
>>
>> submit_bio(type, bio);
>> up_read(&sbi->bio_sem);
>> +
>> + if (type == READ_SYNC) {
>> + wait_on_page_locked(page);
>> + lock_page(page);
>> + if (!PageUptodate(page)) {
>> + f2fs_put_page(page, 1);
>> + return -EIO;
>> + }
>> + }
>> +
>> return 0;
>> }
>>
>> @@ -679,11 +678,7 @@ repeat:
>> err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
>> if (err)
>> return err;
>> - lock_page(page);
>> - if (!PageUptodate(page)) {
>> - f2fs_put_page(page, 1);
>> - return -EIO;
>> - }
>> +
>> if (page->mapping != mapping) {
>> f2fs_put_page(page, 1);
>> goto repeat;
>> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
>> index f5172e2..f061554 100644
>> --- a/fs/f2fs/node.c
>> +++ b/fs/f2fs/node.c
>> @@ -1534,7 +1534,6 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
>> if (f2fs_readpage(sbi, page, addr, READ_SYNC))
>> goto out;
>>
>> - lock_page(page);
>> rn = F2FS_NODE(page);
>> sum_entry->nid = rn->footer.nid;
>> sum_entry->version = 0;
>> diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
>> index 639eb34..ec68183 100644
>> --- a/fs/f2fs/recovery.c
>> +++ b/fs/f2fs/recovery.c
>> @@ -140,8 +140,6 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head)
>> if (err)
>> goto out;
>>
>> - lock_page(page);
>> -
>> if (cp_ver != cpver_of_node(page))
>> break;
>>
>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>> index 9b74ae2..bcd19db 100644
>> --- a/fs/f2fs/segment.c
>> +++ b/fs/f2fs/segment.c
>> @@ -639,7 +639,7 @@ static void do_submit_bio(struct f2fs_sb_info *sbi,
>>
>> trace_f2fs_do_submit_bio(sbi->sb, btype, sync, sbi->bio[btype]);
>>
>> - if (type == META_FLUSH) {
>> + if ((type == META_FLUSH) || (rw & WRITE_SYNC)) {
>> DECLARE_COMPLETION_ONSTACK(wait);
>> p->is_sync = true;
>> p->wait = &wait;
>


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