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

Andreas Gruenbacher
2017-08-29T14:29:50Z

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