[PATCH 1/4] iomap: Switch from blkno to disk offset

[Andreas Gruenbacher <agruenba@redhat.com>]

Replace iomap->blkno, the sector number, with iomap->addr, the disk
offset in bytes.  For invalid disk offsets, use the special value
IOMAP_NULL_ADDR instead of IOMAP_NULL_BLOCK.  This allows to use iomap
for mappings which are not block aligned, such as inline data on ext4
and stuffed inodes on gfs2.

Tested on xfs and ext4 with xfstests; seems to be working correctly.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/buffer.c           |  4 ++--
 fs/dax.c              |  2 +-
 fs/ext2/inode.c       |  4 ++--
 fs/ext4/inode.c       |  4 ++--
 fs/iomap.c            | 11 +++++------
 fs/nfsd/blocklayout.c |  4 ++--
 fs/xfs/xfs_iomap.c    |  6 +++---
 include/linux/iomap.h | 10 +++++-----
 8 files changed, 22 insertions(+), 23 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 5715dac7821f..b9d20076bb8f 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1979,8 +1979,8 @@ iomap_to_bh(struct inode *inode, sector_t block, struct buffer_head *bh,
 	case IOMAP_MAPPED:
 		if (offset >= i_size_read(inode))
 			set_buffer_new(bh);
-		bh->b_blocknr = (iomap->blkno >> (inode->i_blkbits - 9)) +
-				((offset - iomap->offset) >> inode->i_blkbits);
+		bh->b_blocknr = (iomap->addr + offset - iomap->offset) >>
+				inode->i_blkbits;
 		set_buffer_mapped(bh);
 		break;
 	}
diff --git a/fs/dax.c b/fs/dax.c
index 865d42c63e23..539aaa0b9c45 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -987,7 +987,7 @@ EXPORT_SYMBOL_GPL(__dax_zero_page_range);
 
 static sector_t dax_iomap_sector(struct iomap *iomap, loff_t pos)
 {
-	return iomap->blkno + (((pos & PAGE_MASK) - iomap->offset) >> 9);
+	return (iomap->addr + (pos & PAGE_MASK) - iomap->offset) >> 9;
 }
 
 static loff_t
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 30163d007b2f..e7d8925d0140 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -824,11 +824,11 @@ static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
 
 	if (ret == 0) {
 		iomap->type = IOMAP_HOLE;
-		iomap->blkno = IOMAP_NULL_BLOCK;
+		iomap->addr = IOMAP_NULL_ADDR;
 		iomap->length = 1 << blkbits;
 	} else {
 		iomap->type = IOMAP_MAPPED;
-		iomap->blkno = (sector_t)bno << (blkbits - 9);
+		iomap->addr = (u64)bno << blkbits;
 		iomap->length = (u64)ret << blkbits;
 		iomap->flags |= IOMAP_F_MERGED;
 	}
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c774bdc22759..429f0afde9f2 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3483,7 +3483,7 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
 
 	if (ret == 0) {
 		iomap->type = IOMAP_HOLE;
-		iomap->blkno = IOMAP_NULL_BLOCK;
+		iomap->addr = IOMAP_NULL_ADDR;
 		iomap->length = (u64)map.m_len << blkbits;
 	} else {
 		if (map.m_flags & EXT4_MAP_MAPPED) {
@@ -3494,7 +3494,7 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
 			WARN_ON_ONCE(1);
 			return -EIO;
 		}
-		iomap->blkno = (sector_t)map.m_pblk << (blkbits - 9);
+		iomap->addr = (u64)map.m_pblk << blkbits;
 		iomap->length = (u64)map.m_len << blkbits;
 	}
 
diff --git a/fs/iomap.c b/fs/iomap.c
index 59cc98ad7577..7bc1797c2292 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -350,8 +350,8 @@ static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset,
 static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes,
 		struct iomap *iomap)
 {
-	sector_t sector = iomap->blkno +
-		(((pos & ~(PAGE_SIZE - 1)) - iomap->offset) >> 9);
+	sector_t sector = (iomap->addr +
+			   (pos & PAGE_MASK) - iomap->offset) >> 9;
 
 	return __dax_zero_page_range(iomap->bdev, iomap->dax_dev, sector,
 			offset, bytes);
@@ -512,9 +512,8 @@ static int iomap_to_fiemap(struct fiemap_extent_info *fi,
 		flags |= FIEMAP_EXTENT_SHARED;
 
 	return fiemap_fill_next_extent(fi, iomap->offset,
-			iomap->blkno != IOMAP_NULL_BLOCK ? iomap->blkno << 9: 0,
+			iomap->addr != IOMAP_NULL_ADDR ? iomap->addr : 0,
 			iomap->length, flags);
-
 }
 
 static loff_t
@@ -807,7 +806,7 @@ iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos,
 	bio = bio_alloc(GFP_KERNEL, 1);
 	bio->bi_bdev = iomap->bdev;
 	bio->bi_iter.bi_sector =
-		iomap->blkno + ((pos - iomap->offset) >> 9);
+		(iomap->addr + pos - iomap->offset) >> 9;
 	bio->bi_private = dio;
 	bio->bi_end_io = iomap_dio_bio_end_io;
 
@@ -886,7 +885,7 @@ iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length,
 		bio = bio_alloc(GFP_KERNEL, nr_pages);
 		bio->bi_bdev = iomap->bdev;
 		bio->bi_iter.bi_sector =
-			iomap->blkno + ((pos - iomap->offset) >> 9);
+			(iomap->addr + pos - iomap->offset) >> 9;
 		bio->bi_write_hint = dio->iocb->ki_hint;
 		bio->bi_private = dio;
 		bio->bi_end_io = iomap_dio_bio_end_io;
diff --git a/fs/nfsd/blocklayout.c b/fs/nfsd/blocklayout.c
index c862c2489df0..2d1d37b27dc7 100644
--- a/fs/nfsd/blocklayout.c
+++ b/fs/nfsd/blocklayout.c
@@ -65,7 +65,7 @@ nfsd4_block_proc_layoutget(struct inode *inode, const struct svc_fh *fhp,
 			bex->es = PNFS_BLOCK_READ_DATA;
 		else
 			bex->es = PNFS_BLOCK_READWRITE_DATA;
-		bex->soff = (iomap.blkno << 9);
+		bex->soff = iomap.addr;
 		break;
 	case IOMAP_UNWRITTEN:
 		if (seg->iomode & IOMODE_RW) {
@@ -78,7 +78,7 @@ nfsd4_block_proc_layoutget(struct inode *inode, const struct svc_fh *fhp,
 			}
 
 			bex->es = PNFS_BLOCK_INVALID_DATA;
-			bex->soff = (iomap.blkno << 9);
+			bex->soff = iomap.addr;
 			break;
 		}
 		/*FALLTHRU*/
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 813394c62849..1bcc5d0373a5 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -54,13 +54,13 @@ xfs_bmbt_to_iomap(
 	struct xfs_mount	*mp = ip->i_mount;
 
 	if (imap->br_startblock == HOLESTARTBLOCK) {
-		iomap->blkno = IOMAP_NULL_BLOCK;
+		iomap->addr = IOMAP_NULL_ADDR;
 		iomap->type = IOMAP_HOLE;
 	} else if (imap->br_startblock == DELAYSTARTBLOCK) {
-		iomap->blkno = IOMAP_NULL_BLOCK;
+		iomap->addr = IOMAP_NULL_ADDR;
 		iomap->type = IOMAP_DELALLOC;
 	} else {
-		iomap->blkno = xfs_fsb_to_db(ip, imap->br_startblock);
+		iomap->addr = (u64)xfs_fsb_to_db(ip, imap->br_startblock) << 9;
 		if (imap->br_state == XFS_EXT_UNWRITTEN)
 			iomap->type = IOMAP_UNWRITTEN;
 		else
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index f64dc6ce5161..7b8a615fa021 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -15,8 +15,8 @@ struct vm_fault;
  */
 #define IOMAP_HOLE	0x01	/* no blocks allocated, need allocation */
 #define IOMAP_DELALLOC	0x02	/* delayed allocation blocks */
-#define IOMAP_MAPPED	0x03	/* blocks allocated @blkno */
-#define IOMAP_UNWRITTEN	0x04	/* blocks allocated @blkno in unwritten state */
+#define IOMAP_MAPPED	0x03	/* blocks allocated at @addr */
+#define IOMAP_UNWRITTEN	0x04	/* blocks allocated at @addr in unwritten state */
 
 /*
  * Flags for all iomap mappings:
@@ -30,12 +30,12 @@ struct vm_fault;
 #define IOMAP_F_SHARED	0x20	/* block shared with another file */
 
 /*
- * Magic value for blkno:
+ * Magic value for addr:
  */
-#define IOMAP_NULL_BLOCK -1LL	/* blkno is not valid */
+#define IOMAP_NULL_ADDR -1ULL	/* addr is not valid */
 
 struct iomap {
-	sector_t		blkno;	/* 1st sector of mapping, 512b units */
+	u64			addr; /* disk offset of mapping, bytes */
 	loff_t			offset;	/* file offset of mapping, bytes */
 	u64			length;	/* length of mapping, bytes */
 	u16			type;	/* type of mapping */
-- 
2.13.3