* [PATCH] btrfs: remove the unnecessary @nr_written parameters
@ 2021-07-27 6:02 Qu Wenruo
0 siblings, 0 replies; only message in thread
From: Qu Wenruo @ 2021-07-27 6:02 UTC (permalink / raw
To: linux-btrfs
We use @nr_written to record how many pages have been started by
btrfs_run_delalloc_range().
Currently there are only two cases that would populate @nr_written:
- Inline extent creation
- Compressed write
But both cases will also set @page_started to one.
In fact, in writepage_delalloc() we have the following code, showing
that @nr_written is really only utilized for above two cases:
/* did the fill delalloc function already unlock and start
* the IO?
*/
if (page_started) {
/*
* we've unlocked the page, so we can't update
* the mapping's writeback index, just update
* nr_to_write.
*/
wbc->nr_to_write -= nr_written;
return 1;
}
But for such cases, writepage_delalloc() will return 1, and exit
__extent_writepage() without going through __extent_writepage_io().
Thus this means, inside __extent_writepage_io(), we always get
@nr_written as 0.
So this patch is going to remove the unnecessary parameter from the
following functions:
- writepage_delalloc()
As @nr_written passed in is always the initial value 0.
Although inside that function, we still need a local @nr_written
to update wbc->nr_to_write.
- __extent_writepage_io()
As explained above, @nr_written passed in can only be 0.
This also means we can remove one update_nr_written() call.
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
fs/btrfs/extent_io.c | 19 ++++++++-----------
1 file changed, 8 insertions(+), 11 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index b0751920f5ee..d97fb7fca899 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3798,12 +3798,13 @@ static void update_nr_written(struct writeback_control *wbc,
* This returns < 0 if there were errors (page still locked)
*/
static noinline_for_stack int writepage_delalloc(struct btrfs_inode *inode,
- struct page *page, struct writeback_control *wbc,
- unsigned long *nr_written)
+ struct page *page, struct writeback_control *wbc)
{
const u64 page_end = page_offset(page) + PAGE_SIZE - 1;
u64 delalloc_start = page_offset(page);
u64 delalloc_to_write = 0;
+ /* Number of pages started by the delalloc range */
+ unsigned long nr_written = 0;
int ret;
int page_started = 0;
@@ -3819,7 +3820,7 @@ static noinline_for_stack int writepage_delalloc(struct btrfs_inode *inode,
continue;
}
ret = btrfs_run_delalloc_range(inode, page, delalloc_start,
- delalloc_end, &page_started, nr_written, wbc,
+ delalloc_end, &page_started, &nr_written, wbc,
true);
if (ret) {
btrfs_page_set_error(inode->root->fs_info, page,
@@ -3858,7 +3859,7 @@ static noinline_for_stack int writepage_delalloc(struct btrfs_inode *inode,
* the mapping's writeback index, just update
* nr_to_write.
*/
- wbc->nr_to_write -= *nr_written;
+ wbc->nr_to_write -= nr_written;
return 1;
}
@@ -3926,7 +3927,6 @@ static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode,
struct writeback_control *wbc,
struct extent_page_data *epd,
loff_t i_size,
- unsigned long nr_written,
int *nr_ret)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
@@ -3946,7 +3946,6 @@ static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode,
if (ret) {
/* Fixup worker will requeue */
redirty_page_for_writepage(wbc, page);
- update_nr_written(wbc, nr_written);
unlock_page(page);
return 1;
}
@@ -3955,7 +3954,7 @@ static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode,
* we don't want to touch the inode after unlocking the page,
* so we update the mapping writeback index now
*/
- update_nr_written(wbc, nr_written + 1);
+ update_nr_written(wbc, 1);
while (cur <= end) {
u64 disk_bytenr;
@@ -4094,7 +4093,6 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
size_t pg_offset;
loff_t i_size = i_size_read(inode);
unsigned long end_index = i_size >> PAGE_SHIFT;
- unsigned long nr_written = 0;
trace___extent_writepage(page, inode, wbc);
@@ -4123,8 +4121,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
}
if (!epd->extent_locked) {
- ret = writepage_delalloc(BTRFS_I(inode), page, wbc,
- &nr_written);
+ ret = writepage_delalloc(BTRFS_I(inode), page, wbc);
if (ret == 1)
return 0;
if (ret)
@@ -4132,7 +4129,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
}
ret = __extent_writepage_io(BTRFS_I(inode), page, wbc, epd, i_size,
- nr_written, &nr);
+ &nr);
if (ret == 1)
return 0;
--
2.32.0
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