Hi Dmitry&Theodore,
Someone said without the following patch on lts 3.10 kernel (which used
as android base kernel). the write maybe very very slow, needs 1 or 2
seconds to finish.
I quick looked this patch, seems it's no harm for a normal fs function.
but still don't know why it is helpful. So do you remember why you
commit this change at that time?
Thanks
Alex
ommit 7afe5aa59ed3da7b6161617e7f157c7c680dc41e
Author: Dmitry Monakhov <dmonakhov@xxxxxxxxxx>
Date: Wed Aug 28 14:30:47 2013 -0400
ext4: convert write_begin methods to stable_page_writes semantics
Use wait_for_stable_page() instead of wait_on_page_writeback()
Signed-off-by: Dmitry Monakhov <dmonakhov@xxxxxxxxxx>
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index fc4051e..47c8e46 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -969,7 +969,8 @@ retry_journal:
ext4_journal_stop(handle);
goto retry_grab;
}
- wait_on_page_writeback(page);
+ /* In case writeback began while the page was unlocked */
+ wait_for_stable_page(page);
if (ext4_should_dioread_nolock(inode))
ret = __block_write_begin(page, pos, len,
ext4_get_block_write);
@@ -2678,7 +2679,7 @@ retry_journal:
goto retry_grab;
}
/* In case writeback began while the page was unlocked */
- wait_on_page_writeback(page);
+ wait_for_stable_page(page);
ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
if (ret < 0) {
~
--
Thanks
Alex
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