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btrfs: submit a writeback bio per extent_buffer

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Stop trying to cluster writes of multiple extent_buffers into a single
bio.  There is no need for that as the blk_plug mechanism used all the
way up in writeback_inodes_wb gives us the same I/O pattern even with
multiple bios.  Removing the clustering simplifies
lock_extent_buffer_for_io a lot and will also allow passing the eb
as private data to the end I/O handler.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Christoph Hellwig 2023-05-03 17:24:31 +02:00 committed by David Sterba
parent 9fdd160160
commit 50b21d7a06
1 changed files with 37 additions and 65 deletions
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102
fs/btrfs/extent_io.c
View file

@ -1627,41 +1627,24 @@ static void end_extent_buffer_writeback(struct extent_buffer *eb)
/*
* Lock extent buffer status and pages for writeback.
*
* May try to flush write bio if we can't get the lock.
*
* Return %false if the extent buffer doesn't need to be submitted (e.g. the
* extent buffer is not dirty)
* Return %true is the extent buffer is submitted to bio.
*/
static noinline_for_stack bool lock_extent_buffer_for_io(struct extent_buffer *eb,
struct btrfs_bio_ctrl *bio_ctrl)
struct writeback_control *wbc)
{
struct btrfs_fs_info *fs_info = eb->fs_info;
int i, num_pages;
int flush = 0;
bool ret = false;
int i;
if (!btrfs_try_tree_write_lock(eb)) {
submit_write_bio(bio_ctrl, 0);
flush = 1;
btrfs_tree_lock(eb);
}
if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) {
btrfs_tree_lock(eb);
while (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) {
btrfs_tree_unlock(eb);
if (bio_ctrl->wbc->sync_mode != WB_SYNC_ALL)
if (wbc->sync_mode != WB_SYNC_ALL)
return false;
if (!flush) {
submit_write_bio(bio_ctrl, 0);
flush = 1;
}
while (1) {
wait_on_extent_buffer_writeback(eb);
btrfs_tree_lock(eb);
if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
break;
btrfs_tree_unlock(eb);
}
wait_on_extent_buffer_writeback(eb);
btrfs_tree_lock(eb);
}
/*
@ -1693,19 +1676,8 @@ static noinline_for_stack bool lock_extent_buffer_for_io(struct extent_buffer *e
if (!ret || fs_info->nodesize < PAGE_SIZE)
return ret;
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++) {
struct page *p = eb->pages[i];
if (!trylock_page(p)) {
if (!flush) {
submit_write_bio(bio_ctrl, 0);
flush = 1;
}
lock_page(p);
}
}
for (i = 0; i < num_extent_pages(eb); i++)
lock_page(eb->pages[i]);
return ret;
}
@ -1936,11 +1908,16 @@ static void prepare_eb_write(struct extent_buffer *eb)
* Page locking is only utilized at minimum to keep the VMM code happy.
*/
static void write_one_subpage_eb(struct extent_buffer *eb,
struct btrfs_bio_ctrl *bio_ctrl)
struct writeback_control *wbc)
{
struct btrfs_fs_info *fs_info = eb->fs_info;
struct page *page = eb->pages[0];
bool no_dirty_ebs = false;
struct btrfs_bio_ctrl bio_ctrl = {
.wbc = wbc,
.opf = REQ_OP_WRITE | wbc_to_write_flags(wbc),
.end_io_func = end_bio_subpage_eb_writepage,
};
prepare_eb_write(eb);
@ -1954,40 +1931,43 @@ static void write_one_subpage_eb(struct extent_buffer *eb,
if (no_dirty_ebs)
clear_page_dirty_for_io(page);
bio_ctrl->end_io_func = end_bio_subpage_eb_writepage;
submit_extent_page(bio_ctrl, eb->start, page, eb->len,
submit_extent_page(&bio_ctrl, eb->start, page, eb->len,
eb->start - page_offset(page));
unlock_page(page);
submit_one_bio(&bio_ctrl);
/*
* Submission finished without problem, if no range of the page is
* dirty anymore, we have submitted a page. Update nr_written in wbc.
*/
if (no_dirty_ebs)
bio_ctrl->wbc->nr_to_write--;
wbc->nr_to_write--;
}
static noinline_for_stack void write_one_eb(struct extent_buffer *eb,
struct btrfs_bio_ctrl *bio_ctrl)
struct writeback_control *wbc)
{
u64 disk_bytenr = eb->start;
int i, num_pages;
struct btrfs_bio_ctrl bio_ctrl = {
.wbc = wbc,
.opf = REQ_OP_WRITE | wbc_to_write_flags(wbc),
.end_io_func = end_bio_extent_buffer_writepage,
};
prepare_eb_write(eb);
bio_ctrl->end_io_func = end_bio_extent_buffer_writepage;
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++) {
struct page *p = eb->pages[i];
clear_page_dirty_for_io(p);
set_page_writeback(p);
submit_extent_page(bio_ctrl, disk_bytenr, p, PAGE_SIZE, 0);
submit_extent_page(&bio_ctrl, disk_bytenr, p, PAGE_SIZE, 0);
disk_bytenr += PAGE_SIZE;
bio_ctrl->wbc->nr_to_write--;
wbc->nr_to_write--;
unlock_page(p);
}
submit_one_bio(&bio_ctrl);
}
/*
@ -2004,7 +1984,7 @@ static noinline_for_stack void write_one_eb(struct extent_buffer *eb,
* Return >=0 for the number of submitted extent buffers.
* Return <0 for fatal error.
*/
static int submit_eb_subpage(struct page *page, struct btrfs_bio_ctrl *bio_ctrl)
static int submit_eb_subpage(struct page *page, struct writeback_control *wbc)
{
struct btrfs_fs_info *fs_info = btrfs_sb(page->mapping->host->i_sb);
int submitted = 0;
@ -2056,8 +2036,8 @@ static int submit_eb_subpage(struct page *page, struct btrfs_bio_ctrl *bio_ctrl)
if (!eb)
continue;
if (lock_extent_buffer_for_io(eb, bio_ctrl)) {
write_one_subpage_eb(eb, bio_ctrl);
if (lock_extent_buffer_for_io(eb, wbc)) {
write_one_subpage_eb(eb, wbc);
submitted++;
}
free_extent_buffer(eb);
@ -2085,7 +2065,7 @@ static int submit_eb_subpage(struct page *page, struct btrfs_bio_ctrl *bio_ctrl)
* previous call.
* Return <0 for fatal error.
*/
static int submit_eb_page(struct page *page, struct btrfs_bio_ctrl *bio_ctrl,
static int submit_eb_page(struct page *page, struct writeback_control *wbc,
struct extent_buffer **eb_context)
{
struct address_space *mapping = page->mapping;
@ -2097,7 +2077,7 @@ static int submit_eb_page(struct page *page, struct btrfs_bio_ctrl *bio_ctrl,
return 0;
if (btrfs_sb(page->mapping->host->i_sb)->nodesize < PAGE_SIZE)
return submit_eb_subpage(page, bio_ctrl);
return submit_eb_subpage(page, wbc);
spin_lock(&mapping->private_lock);
if (!PagePrivate(page)) {
@ -2130,8 +2110,7 @@ static int submit_eb_page(struct page *page, struct btrfs_bio_ctrl *bio_ctrl,
* If for_sync, this hole will be filled with
* trasnsaction commit.
*/
if (bio_ctrl->wbc->sync_mode == WB_SYNC_ALL &&
!bio_ctrl->wbc->for_sync)
if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync)
ret = -EAGAIN;
else
ret = 0;
@ -2141,12 +2120,12 @@ static int submit_eb_page(struct page *page, struct btrfs_bio_ctrl *bio_ctrl,
*eb_context = eb;
if (!lock_extent_buffer_for_io(eb, bio_ctrl)) {
if (!lock_extent_buffer_for_io(eb, wbc)) {
btrfs_revert_meta_write_pointer(cache, eb);
if (cache)
btrfs_put_block_group(cache);
free_extent_buffer(eb);
return ret;
return 0;
}
if (cache) {
/*
@ -2155,7 +2134,7 @@ static int submit_eb_page(struct page *page, struct btrfs_bio_ctrl *bio_ctrl,
btrfs_schedule_zone_finish_bg(cache, eb);
btrfs_put_block_group(cache);
}
write_one_eb(eb, bio_ctrl);
write_one_eb(eb, wbc);
free_extent_buffer(eb);
return 1;
}
@ -2164,11 +2143,6 @@ int btree_write_cache_pages(struct address_space *mapping,
struct writeback_control *wbc)
{
struct extent_buffer *eb_context = NULL;
struct btrfs_bio_ctrl bio_ctrl = {
.wbc = wbc,
.opf = REQ_OP_WRITE | wbc_to_write_flags(wbc),
.extent_locked = 0,
};
struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info;
int ret = 0;
int done = 0;
@ -2210,7 +2184,7 @@ int btree_write_cache_pages(struct address_space *mapping,
for (i = 0; i < nr_folios; i++) {
struct folio *folio = fbatch.folios[i];
ret = submit_eb_page(&folio->page, &bio_ctrl, &eb_context);
ret = submit_eb_page(&folio->page, wbc, &eb_context);
if (ret == 0)
continue;
if (ret < 0) {
@ -2271,8 +2245,6 @@ int btree_write_cache_pages(struct address_space *mapping,
ret = 0;
if (!ret && BTRFS_FS_ERROR(fs_info))
ret = -EROFS;
submit_write_bio(&bio_ctrl, ret);
btrfs_zoned_meta_io_unlock(fs_info);
return ret;
}