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Commit bafc0dba authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
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buffer, writeback: make __block_write_full_page() honor cgroup writeback 



[__]block_write_full_page() is used to implement ->writepage in
various filesystems.  All writeback logic is now updated to handle
cgroup writeback and the block cgroup to issue IOs for is encoded in
writeback_control and can be retrieved from the inode; however,
[__]block_write_full_page() currently ignores the blkcg indicated by
inode and issues all bio's without explicit blkcg association.

This patch adds submit_bh_blkcg() which associates the bio with the
specified blkio cgroup before issuing and uses it in
__block_write_full_page() so that the issued bio's are associated with
inode_to_wb_blkcg_css(inode).

v2: Updated for per-inode wb association.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 0747259d

fs/buffer.c

+20 −6
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ 
#include <linux/quotaops.h>

#include <linux/highmem.h>

#include <linux/export.h>

#include <linux/backing-dev.h>

#include <linux/writeback.h>

#include <linux/hash.h>

#include <linux/suspend.h>
@@ -44,6 +45,9 @@ 
#include <trace/events/block.h>



static int fsync_buffers_list(spinlock_t *lock, struct list_head *list);

static int submit_bh_blkcg(int rw, struct buffer_head *bh,

			   unsigned long bio_flags,

			   struct cgroup_subsys_state *blkcg_css);



#define BH_ENTRY(list) list_entry((list), struct buffer_head, b_assoc_buffers)
@@ -1704,8 +1708,8 @@ static int __block_write_full_page(struct inode *inode, struct page *page, 
	struct buffer_head *bh, *head;

	unsigned int blocksize, bbits;

	int nr_underway = 0;

	int write_op = (wbc->sync_mode == WB_SYNC_ALL ?

			WRITE_SYNC : WRITE);

	int write_op = (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE);

	struct cgroup_subsys_state *blkcg_css = inode_to_wb_blkcg_css(inode);



	head = create_page_buffers(page, inode,

					(1 << BH_Dirty)|(1 << BH_Uptodate));
@@ -1794,7 +1798,7 @@ static int __block_write_full_page(struct inode *inode, struct page *page, 
	do {

		struct buffer_head *next = bh->b_this_page;

		if (buffer_async_write(bh)) {

			submit_bh(write_op, bh);

			submit_bh_blkcg(write_op, bh, 0, blkcg_css);

			nr_underway++;

		}

		bh = next;
@@ -1848,7 +1852,7 @@ static int __block_write_full_page(struct inode *inode, struct page *page, 
		struct buffer_head *next = bh->b_this_page;

		if (buffer_async_write(bh)) {

			clear_buffer_dirty(bh);

			submit_bh(write_op, bh);

			submit_bh_blkcg(write_op, bh, 0, blkcg_css);

			nr_underway++;

		}

		bh = next;
@@ -3013,7 +3017,9 @@ void guard_bio_eod(int rw, struct bio *bio) 
	}

}



int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags)

static int submit_bh_blkcg(int rw, struct buffer_head *bh,

			   unsigned long bio_flags,

			   struct cgroup_subsys_state *blkcg_css)

{

	struct bio *bio;
@@ -3035,6 +3041,9 @@ int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags) 
	 */

	bio = bio_alloc(GFP_NOIO, 1);



	if (blkcg_css)

		bio_associate_blkcg(bio, blkcg_css);



	bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);

	bio->bi_bdev = bh->b_bdev;

	bio->bi_io_vec[0].bv_page = bh->b_page;
@@ -3059,11 +3068,16 @@ int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags) 
	submit_bio(rw, bio);

	return 0;

}



int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags)

{

	return submit_bh_blkcg(rw, bh, bio_flags, NULL);

}

EXPORT_SYMBOL_GPL(_submit_bh);



int submit_bh(int rw, struct buffer_head *bh)

{

	return _submit_bh(rw, bh, 0);

	return submit_bh_blkcg(rw, bh, 0, NULL);

}

EXPORT_SYMBOL(submit_bh);

include/linux/backing-dev.h

+12 −0
Original line number Diff line number Diff line
@@ -393,6 +393,12 @@ static inline struct bdi_writeback *inode_to_wb(struct inode *inode) 
	return inode->i_wb;

}



static inline struct cgroup_subsys_state *

inode_to_wb_blkcg_css(struct inode *inode)

{

	return inode_to_wb(inode)->blkcg_css;

}



struct wb_iter {

	int			start_blkcg_id;

	struct radix_tree_iter	tree_iter;
@@ -510,6 +516,12 @@ static inline void wb_blkcg_offline(struct blkcg *blkcg) 
{

}



static inline struct cgroup_subsys_state *

inode_to_wb_blkcg_css(struct inode *inode)

{

	return blkcg_root_css;

}



struct wb_iter {

	int		next_id;

};