Merge tag 'for-linus-20190620' of git://git.kernel.dk/linux-block

Pull block fixes from Jens Axboe:
 "Three fixes that should go into this series.

  One is a set of two patches from Christoph, fixing a page leak on same
  page merges. Boiled down version of a bigger fix, but this one is more
  appropriate for this late in the cycle (and easier to backport to
  stable).

  The last patch is for a divide error in MD, from Mariusz (via Song)"

* tag 'for-linus-20190620' of git://git.kernel.dk/linux-block:
  md: fix for divide error in status_resync
  block: fix page leak when merging to same page
  block: return from __bio_try_merge_page if merging occured in the same page

2 files changed, 16 insertions, 7 deletions

diff --git a/fs/iomap.c b/fs/iomap.c
index 23ef63fd1669..12654c2e78f8 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -287,7 +287,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 	struct iomap_readpage_ctx *ctx = data;
 	struct page *page = ctx->cur_page;
 	struct iomap_page *iop = iomap_page_create(inode, page);
-	bool is_contig = false;
+	bool same_page = false, is_contig = false;
 	loff_t orig_pos = pos;
 	unsigned poff, plen;
 	sector_t sector;
@@ -315,10 +315,14 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 	 * Try to merge into a previous segment if we can.
 	 */
 	sector = iomap_sector(iomap, pos);
-	if (ctx->bio && bio_end_sector(ctx->bio) == sector) {
-		if (__bio_try_merge_page(ctx->bio, page, plen, poff, true))
-			goto done;
+	if (ctx->bio && bio_end_sector(ctx->bio) == sector)
 		is_contig = true;
+
+	if (is_contig &&
+	    __bio_try_merge_page(ctx->bio, page, plen, poff, &same_page)) {
+		if (!same_page && iop)
+			atomic_inc(&iop->read_count);
+		goto done;
 	}
 
 	/*
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index a6f0f4761a37..8da5e6637771 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -758,6 +758,7 @@ xfs_add_to_ioend(
 	struct block_device	*bdev = xfs_find_bdev_for_inode(inode);
 	unsigned		len = i_blocksize(inode);
 	unsigned		poff = offset & (PAGE_SIZE - 1);
+	bool			merged, same_page = false;
 	sector_t		sector;
 
 	sector = xfs_fsb_to_db(ip, wpc->imap.br_startblock) +
@@ -774,9 +775,13 @@ xfs_add_to_ioend(
 				wpc->imap.br_state, offset, bdev, sector);
 	}
 
-	if (!__bio_try_merge_page(wpc->ioend->io_bio, page, len, poff, true)) {
-		if (iop)
-			atomic_inc(&iop->write_count);
+	merged = __bio_try_merge_page(wpc->ioend->io_bio, page, len, poff,
+			&same_page);
+
+	if (iop && !same_page)
+		atomic_inc(&iop->write_count);
+
+	if (!merged) {
 		if (bio_full(wpc->ioend->io_bio))
 			xfs_chain_bio(wpc->ioend, wbc, bdev, sector);
 		bio_add_page(wpc->ioend->io_bio, page, len, poff);