[PATCH 13/18] xfs: don't look at buffer heads in xfs_add_to_ioend

Christoph Hellwig
2018-05-30T10:01:15Z

Calculate all information for the bio based on the passed in information
without requiring a buffer_head structure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/xfs_aops.c | 68 ++++++++++++++++++++++-------------------------
1 file changed, 32 insertions(+), 36 deletions(-)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 910b410e5a90..7d02d04d5a5b 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -44,7 +44,6 @@ struct xfs_writepage_ctx {
struct xfs_bmbt_irec imap;
unsigned int io_type;
struct xfs_ioend *ioend;
- sector_t last_block;
};

void
@@ -535,11 +534,6 @@ xfs_start_page_writeback(
unlock_page(page);
}

-static inline int xfs_bio_add_buffer(struct bio *bio, struct buffer_head *bh)
-{
- return bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh));
-}
-
/*
* Submit the bio for an ioend. We are passed an ioend with a bio attached to
* it, and we submit that bio. The ioend may be used for multiple bio
@@ -594,27 +588,20 @@ xfs_submit_ioend(
return 0;
}

-static void
-xfs_init_bio_from_bh(
- struct bio *bio,
- struct buffer_head *bh)
-{
- bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
- bio_set_dev(bio, bh->b_bdev);
-}
-
static struct xfs_ioend *
xfs_alloc_ioend(
struct inode *inode,
unsigned int type,
xfs_off_t offset,
- struct buffer_head *bh)
+ struct block_device *bdev,
+ sector_t sector)
{
struct xfs_ioend *ioend;
struct bio *bio;

bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_PAGES, xfs_ioend_bioset);
- xfs_init_bio_from_bh(bio, bh);
+ bio_set_dev(bio, bdev);
+ bio->bi_iter.bi_sector = sector;

ioend = container_of(bio, struct xfs_ioend, io_inline_bio);
INIT_LIST_HEAD(&ioend->io_list);
@@ -639,13 +626,14 @@ static void
xfs_chain_bio(
struct xfs_ioend *ioend,
struct writeback_control *wbc,
- struct buffer_head *bh)
+ struct block_device *bdev,
+ sector_t sector)
{
struct bio *new;

new = bio_alloc(GFP_NOFS, BIO_MAX_PAGES);
- xfs_init_bio_from_bh(new, bh);
-
+ bio_set_dev(new, bdev);
+ new->bi_iter.bi_sector = sector;
bio_chain(ioend->io_bio, new);
bio_get(ioend->io_bio); /* for xfs_destroy_ioend */
ioend->io_bio->bi_opf = REQ_OP_WRITE | wbc_to_write_flags(wbc);
@@ -655,39 +643,45 @@ xfs_chain_bio(
}

/*
- * Test to see if we've been building up a completion structure for
- * earlier buffers -- if so, we try to append to this ioend if we
- * can, otherwise we finish off any current ioend and start another.
- * Return the ioend we finished off so that the caller can submit it
- * once it has finished processing the dirty page.
+ * Test to see if we have an existing ioend structure that we could append to
+ * first, otherwise finish off the current ioend and start another.
*/
STATIC void
xfs_add_to_ioend(
struct inode *inode,
- struct buffer_head *bh,
xfs_off_t offset,
+ struct page *page,
struct xfs_writepage_ctx *wpc,
struct writeback_control *wbc,
struct list_head *iolist)
{
+ struct xfs_inode *ip = XFS_I(inode);
+ struct xfs_mount *mp = ip->i_mount;
+ struct block_device *bdev = xfs_find_bdev_for_inode(inode);
+ unsigned len = i_blocksize(inode);
+ unsigned poff = offset & (PAGE_SIZE - 1);
+ sector_t sector;
+
+ sector = xfs_fsb_to_db(ip, wpc->imap.br_startblock) +
+ ((offset - XFS_FSB_TO_B(mp, wpc->imap.br_startoff)) >> 9);
+
if (!wpc->ioend || wpc->io_type != wpc->ioend->io_type ||
- bh->b_blocknr != wpc->last_block + 1 ||
+ sector != bio_end_sector(wpc->ioend->io_bio) ||
offset != wpc->ioend->io_offset + wpc->ioend->io_size) {
if (wpc->ioend)
list_add(&wpc->ioend->io_list, iolist);
- wpc->ioend = xfs_alloc_ioend(inode, wpc->io_type, offset, bh);
+ wpc->ioend = xfs_alloc_ioend(inode, wpc->io_type, offset,
+ bdev, sector);
}

/*
- * If the buffer doesn't fit into the bio we need to allocate a new
- * one. This shouldn't happen more than once for a given buffer.
+ * If the block doesn't fit into the bio we need to allocate a new
+ * one. This shouldn't happen more than once for a given block.
*/
- while (xfs_bio_add_buffer(wpc->ioend->io_bio, bh) != bh->b_size)
- xfs_chain_bio(wpc->ioend, wbc, bh);
+ while (bio_add_page(wpc->ioend->io_bio, page, len, poff) != len)
+ xfs_chain_bio(wpc->ioend, wbc, bdev, sector);

- wpc->ioend->io_size += bh->b_size;
- wpc->last_block = bh->b_blocknr;
- xfs_start_buffer_writeback(bh);
+ wpc->ioend->io_size += len;
}

STATIC void
@@ -883,7 +877,9 @@ xfs_writepage_map(

lock_buffer(bh);
xfs_map_at_offset(inode, bh, &wpc->imap, file_offset);
- xfs_add_to_ioend(inode, bh, file_offset, wpc, wbc, &submit_list);
+ xfs_add_to_ioend(inode, file_offset, page, wpc, wbc,
+ &submit_list);
+ xfs_start_buffer_writeback(bh);
count++;
}

--
2.17.0