From: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
btrfs_dax_zero_block() zeros part of the page, either from the
front or the regular rest of the block.
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
---
fs/btrfs/ctree.h | 1 +
fs/btrfs/dax.c | 29 +++++++++++++++++++++++++++--
fs/btrfs/inode.c | 4 ++++
fs/dax.c | 17 ++++++++++++-----
fs/iomap.c | 9 +--------
include/linux/dax.h | 11 +++++------
include/linux/iomap.h | 6 ++++++
7 files changed, 56 insertions(+), 21 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 750f9c70fabe..21068dc4a95a 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3806,6 +3806,7 @@ vm_fault_t btrfs_dax_fault(struct vm_fault *vmf);
int btrfs_dax_file_range_compare(struct inode *src, loff_t srcoff,
struct inode *dest, loff_t destoff, loff_t len,
bool *is_same);
+int btrfs_dax_zero_block(struct inode *inode, loff_t from, loff_t len, bool front);
#else
static inline ssize_t btrfs_file_dax_write(struct kiocb *iocb, struct iov_iter *from)
{
diff --git a/fs/btrfs/dax.c b/fs/btrfs/dax.c
index 7900b5773829..d73945d50b88 100644
--- a/fs/btrfs/dax.c
+++ b/fs/btrfs/dax.c
@@ -31,7 +31,7 @@ static int btrfs_iomap_begin(struct inode *inode, loff_t pos,
em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, pos, length, 0);
- if (flags & IOMAP_WRITE) {
+ if (flags & (IOMAP_WRITE | IOMAP_ZERO)) {
int ret = 0, nocow;
struct extent_map *map = em;
struct btrfs_iomap *bi;
@@ -89,7 +89,8 @@ static int btrfs_iomap_begin(struct inode *inode, loff_t pos,
iomap->bdev = em->bdev;
iomap->dax_dev = fs_info->dax_dev;
- if (em->block_start == EXTENT_MAP_HOLE) {
+ if (em->block_start == EXTENT_MAP_HOLE ||
+ em->flags == EXTENT_FLAG_FILLING) {
iomap->type = IOMAP_HOLE;
return 0;
}
@@ -178,4 +179,28 @@ int btrfs_dax_file_range_compare(struct inode *src, loff_t srcoff,
{
return dax_file_range_compare(src, srcoff, dest, destoff, len, is_same, &btrfs_iomap_ops);
}
+
+/*
+ * zero a part of the page only. This should CoW (via iomap_begin) if required
+ */
+int btrfs_dax_zero_block(struct inode *inode, loff_t from, loff_t len, bool front)
+{
+ loff_t start = round_down(from, PAGE_SIZE);
+ loff_t end = round_up(from, PAGE_SIZE);
+ loff_t offset = from;
+ int ret = 0;
+
+ if (front) {
+ len = from - start;
+ offset = start;
+ } else {
+ if (!len)
+ len = end - from;
+ }
+
+ if (len)
+ ret = iomap_zero_range(inode, offset, len, NULL, &btrfs_iomap_ops);
+
+ return (ret < 0) ? ret : 0;
+}
#endif /* CONFIG_FS_DAX */
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 21780ea14e5a..5350e5f23728 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4833,6 +4833,10 @@ int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len,
(!len || IS_ALIGNED(len, blocksize)))
goto out;
+#ifdef CONFIG_FS_DAX
+ if (IS_DAX(inode))
+ return btrfs_dax_zero_block(inode, from, len, front);
+#endif
block_start = round_down(from, blocksize);
block_end = block_start + blocksize - 1;
diff --git a/fs/dax.c b/fs/dax.c
index 18998c5ee27a..93146142bb00 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1068,17 +1068,21 @@ static void dax_to_dax_copy(struct iomap *iomap, loff_t pos, void *daddr,
blk_start = iomap->cow_addr + pos - iomap->cow_pos;
blk_pg = round_down(blk_start, PAGE_SIZE);
- map_len = dax_direct_access(iomap->dax_dev, PHYS_PFN(blk_pg), PAGE_SIZE,
+ map_len = dax_direct_access(iomap->dax_dev, PHYS_PFN(blk_pg), 1,
&saddr, NULL);
saddr += blk_start - blk_pg;
memcpy(daddr, saddr, len);
}
-int __dax_zero_page_range(struct block_device *bdev,
- struct dax_device *dax_dev, sector_t sector,
- unsigned int offset, unsigned int size)
+int __dax_zero_page_range(struct iomap *iomap, loff_t pos,
+ unsigned int offset, unsigned int size)
{
- if (dax_range_is_aligned(bdev, offset, size)) {
+ sector_t sector = iomap_sector(iomap, pos & PAGE_MASK);
+ struct block_device *bdev = iomap->bdev;
+ struct dax_device *dax_dev = iomap->dax_dev;
+
+ if (!(iomap->flags & IOMAP_F_COW) &&
+ dax_range_is_aligned(bdev, offset, size)) {
sector_t start_sector = sector + (offset >> 9);
return blkdev_issue_zeroout(bdev, start_sector,
@@ -1098,6 +1102,9 @@ int __dax_zero_page_range(struct block_device *bdev,
dax_read_unlock(id);
return rc;
}
+ if (iomap->flags & IOMAP_F_COW)
+ dax_to_dax_copy(iomap, pos & PAGE_MASK,
+ kaddr, PAGE_SIZE);
memset(kaddr + offset, 0, size);
dax_flush(dax_dev, kaddr + offset, size);
dax_read_unlock(id);
diff --git a/fs/iomap.c b/fs/iomap.c
index abdd18e404f8..90698c854883 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -98,12 +98,6 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
return written ? written : ret;
}
-static sector_t
-iomap_sector(struct iomap *iomap, loff_t pos)
-{
- return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
-}
-
static struct iomap_page *
iomap_page_create(struct inode *inode, struct page *page)
{
@@ -990,8 +984,7 @@ 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)
{
- return __dax_zero_page_range(iomap->bdev, iomap->dax_dev,
- iomap_sector(iomap, pos & PAGE_MASK), offset, bytes);
+ return __dax_zero_page_range(iomap, pos, offset, bytes);
}
static loff_t
diff --git a/include/linux/dax.h b/include/linux/dax.h
index a11bc7b1f526..892c478d7073 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -9,6 +9,7 @@
typedef unsigned long dax_entry_t;
+struct iomap;
struct iomap_ops;
struct dax_device;
struct dax_operations {
@@ -161,13 +162,11 @@ int dax_file_range_compare(struct inode *src, loff_t srcoff, struct inode *dest,
loff_t destoff, loff_t len, bool *is_same, const struct iomap_ops *ops);
#ifdef CONFIG_FS_DAX
-int __dax_zero_page_range(struct block_device *bdev,
- struct dax_device *dax_dev, sector_t sector,
- unsigned int offset, unsigned int length);
+int __dax_zero_page_range(struct iomap *iomap, loff_t pos,
+ unsigned int offset, unsigned int size);
#else
-static inline int __dax_zero_page_range(struct block_device *bdev,
- struct dax_device *dax_dev, sector_t sector,
- unsigned int offset, unsigned int length)
+static inline int __dax_zero_page_range(struct iomap *iomap, loff_t pos,
+ unsigned int offset, unsigned int size)
{
return -ENXIO;
}
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 391785de1428..e5a1b2a1962d 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -7,6 +7,7 @@
#include <linux/mm.h>
#include <linux/types.h>
#include <linux/mm_types.h>
+#include <linux/blkdev.h>
struct address_space;
struct fiemap_extent_info;
@@ -122,6 +123,11 @@ static inline struct iomap_page *to_iomap_page(struct page *page)
return NULL;
}
+static inline sector_t iomap_sector(struct iomap *iomap, loff_t pos)
+{
+ return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
+}
+
ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
const struct iomap_ops *ops);
int iomap_readpage(struct page *page, const struct iomap_ops *ops);
--
2.16.4
