From: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
Introduces a new type IOMAP_COW, which means the data at offset
must be read from a srcmap and copied before performing the
write on the offset.
The srcmap is used to identify where the read is to be performed
from. This is passed to iomap->begin(), which is supposed to
put in the details for reading, typically set with type IOMAP_READ.
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
---
fs/dax.c | 8 +++++---
fs/ext2/inode.c | 2 +-
fs/ext4/inode.c | 2 +-
fs/gfs2/bmap.c | 3 ++-
fs/internal.h | 2 +-
fs/iomap.c | 31 ++++++++++++++++---------------
fs/xfs/xfs_iomap.c | 9 ++++++---
include/linux/iomap.h | 4 +++-
8 files changed, 35 insertions(+), 26 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index 2e48c7ebb973..80b9e2599223 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1078,7 +1078,7 @@ EXPORT_SYMBOL_GPL(__dax_zero_page_range);
static loff_t
dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
- struct iomap *iomap)
+ struct iomap *iomap, struct iomap *srcmap)
{
struct block_device *bdev = iomap->bdev;
struct dax_device *dax_dev = iomap->dax_dev;
@@ -1236,6 +1236,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
unsigned long vaddr = vmf->address;
loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT;
struct iomap iomap = { 0 };
+ struct iomap srcmap = { 0 };
unsigned flags = IOMAP_FAULT;
int error, major = 0;
bool write = vmf->flags & FAULT_FLAG_WRITE;
@@ -1280,7 +1281,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
* the file system block size to be equal the page size, which means
* that we never have to deal with more than a single extent here.
*/
- error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap);
+ error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap, &srcmap);
if (iomap_errp)
*iomap_errp = error;
if (error) {
@@ -1460,6 +1461,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
struct inode *inode = mapping->host;
vm_fault_t result = VM_FAULT_FALLBACK;
struct iomap iomap = { 0 };
+ struct iomap srcmap = { 0 };
pgoff_t max_pgoff;
void *entry;
loff_t pos;
@@ -1534,7 +1536,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
* to look up our filesystem block.
*/
pos = (loff_t)xas.xa_index << PAGE_SHIFT;
- error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap);
+ error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap, &srcmap);
if (error)
goto unlock_entry;
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index e474127dd255..f081f11980ad 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -801,7 +801,7 @@ int ext2_get_block(struct inode *inode, sector_t iblock,
#ifdef CONFIG_FS_DAX
static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
- unsigned flags, struct iomap *iomap)
+ unsigned flags, struct iomap *iomap, struct iomap *srcmap)
{
unsigned int blkbits = inode->i_blkbits;
unsigned long first_block = offset >> blkbits;
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c7f77c643008..a8017e0c302b 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3437,7 +3437,7 @@ static bool ext4_inode_datasync_dirty(struct inode *inode)
}
static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
- unsigned flags, struct iomap *iomap)
+ unsigned flags, struct iomap *iomap, struct iomap *srcmap)
{
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
unsigned int blkbits = inode->i_blkbits;
diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 93ea1d529aa3..affa0c4305b7 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -1124,7 +1124,8 @@ static int gfs2_iomap_begin_write(struct inode *inode, loff_t pos,
}
static int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
- unsigned flags, struct iomap *iomap)
+ unsigned flags, struct iomap *iomap,
+ struct iomap *srcmap)
{
struct gfs2_inode *ip = GFS2_I(inode);
struct metapath mp = { .mp_aheight = 1, };
diff --git a/fs/internal.h b/fs/internal.h
index a48ef81be37d..79e495d86165 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -188,7 +188,7 @@ extern int do_vfs_ioctl(struct file *file, unsigned int fd, unsigned int cmd,
* iomap support:
*/
typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len,
- void *data, struct iomap *iomap);
+ void *data, struct iomap *iomap, struct iomap *srcmap);
loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length,
unsigned flags, const struct iomap_ops *ops, void *data,
diff --git a/fs/iomap.c b/fs/iomap.c
index 23ef63fd1669..6648957af268 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -41,6 +41,7 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
const struct iomap_ops *ops, void *data, iomap_actor_t actor)
{
struct iomap iomap = { 0 };
+ struct iomap srcmap = { 0 };
loff_t written = 0, ret;
/*
@@ -55,7 +56,7 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
* expose transient stale data. If the reserve fails, we can safely
* back out at this point as there is nothing to undo.
*/
- ret = ops->iomap_begin(inode, pos, length, flags, &iomap);
+ ret = ops->iomap_begin(inode, pos, length, flags, &iomap, &srcmap);
if (ret)
return ret;
if (WARN_ON(iomap.offset > pos))
@@ -75,7 +76,7 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
* we can do the copy-in page by page without having to worry about
* failures exposing transient data.
*/
- written = actor(inode, pos, length, data, &iomap);
+ written = actor(inode, pos, length, data, &iomap, &srcmap);
/*
* Now the data has been copied, commit the range we've copied. This
@@ -282,7 +283,7 @@ iomap_read_inline_data(struct inode *inode, struct page *page,
static loff_t
iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
- struct iomap *iomap)
+ struct iomap *iomap, struct iomap *srcmap)
{
struct iomap_readpage_ctx *ctx = data;
struct page *page = ctx->cur_page;
@@ -424,7 +425,7 @@ iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos,
static loff_t
iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length,
- void *data, struct iomap *iomap)
+ void *data, struct iomap *iomap, struct iomap *srcmap)
{
struct iomap_readpage_ctx *ctx = data;
loff_t done, ret;
@@ -444,7 +445,7 @@ iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length,
ctx->cur_page_in_bio = false;
}
ret = iomap_readpage_actor(inode, pos + done, length - done,
- ctx, iomap);
+ ctx, iomap, srcmap);
}
return done;
@@ -796,7 +797,7 @@ iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
static loff_t
iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
- struct iomap *iomap)
+ struct iomap *iomap, struct iomap *srcmap)
{
struct iov_iter *i = data;
long status = 0;
@@ -913,7 +914,7 @@ __iomap_read_page(struct inode *inode, loff_t offset)
static loff_t
iomap_dirty_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
- struct iomap *iomap)
+ struct iomap *iomap, struct iomap *srcmap)
{
long status = 0;
ssize_t written = 0;
@@ -1002,7 +1003,7 @@ static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes,
static loff_t
iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count,
- void *data, struct iomap *iomap)
+ void *data, struct iomap *iomap, struct iomap *srcmap)
{
bool *did_zero = data;
loff_t written = 0;
@@ -1071,7 +1072,7 @@ EXPORT_SYMBOL_GPL(iomap_truncate_page);
static loff_t
iomap_page_mkwrite_actor(struct inode *inode, loff_t pos, loff_t length,
- void *data, struct iomap *iomap)
+ void *data, struct iomap *iomap, struct iomap *srcmap)
{
struct page *page = data;
int ret;
@@ -1169,7 +1170,7 @@ static int iomap_to_fiemap(struct fiemap_extent_info *fi,
static loff_t
iomap_fiemap_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
- struct iomap *iomap)
+ struct iomap *iomap, struct iomap *srcmap)
{
struct fiemap_ctx *ctx = data;
loff_t ret = length;
@@ -1343,7 +1344,7 @@ page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length,
static loff_t
iomap_seek_hole_actor(struct inode *inode, loff_t offset, loff_t length,
- void *data, struct iomap *iomap)
+ void *data, struct iomap *iomap, struct iomap *srcmap)
{
switch (iomap->type) {
case IOMAP_UNWRITTEN:
@@ -1389,7 +1390,7 @@ EXPORT_SYMBOL_GPL(iomap_seek_hole);
static loff_t
iomap_seek_data_actor(struct inode *inode, loff_t offset, loff_t length,
- void *data, struct iomap *iomap)
+ void *data, struct iomap *iomap, struct iomap *srcmap)
{
switch (iomap->type) {
case IOMAP_HOLE:
@@ -1790,7 +1791,7 @@ iomap_dio_inline_actor(struct inode *inode, loff_t pos, loff_t length,
static loff_t
iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length,
- void *data, struct iomap *iomap)
+ void *data, struct iomap *iomap, struct iomap *srcmap)
{
struct iomap_dio *dio = data;
@@ -2057,7 +2058,7 @@ static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi)
* distinction between written and unwritten extents.
*/
static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos,
- loff_t count, void *data, struct iomap *iomap)
+ loff_t count, void *data, struct iomap *iomap, struct iomap *srcmap)
{
struct iomap_swapfile_info *isi = data;
int error;
@@ -2161,7 +2162,7 @@ EXPORT_SYMBOL_GPL(iomap_swapfile_activate);
static loff_t
iomap_bmap_actor(struct inode *inode, loff_t pos, loff_t length,
- void *data, struct iomap *iomap)
+ void *data, struct iomap *iomap, struct iomap *srcmap)
{
sector_t *bno = data, addr;
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 63d323916bba..6116a75f03da 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -925,7 +925,8 @@ xfs_file_iomap_begin(
loff_t offset,
loff_t length,
unsigned flags,
- struct iomap *iomap)
+ struct iomap *iomap,
+ struct iomap *srcmap)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
@@ -1148,7 +1149,8 @@ xfs_seek_iomap_begin(
loff_t offset,
loff_t length,
unsigned flags,
- struct iomap *iomap)
+ struct iomap *iomap,
+ struct iomap *srcmap)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
@@ -1234,7 +1236,8 @@ xfs_xattr_iomap_begin(
loff_t offset,
loff_t length,
unsigned flags,
- struct iomap *iomap)
+ struct iomap *iomap,
+ struct iomap *srcmap)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 2103b94cb1bf..f49767c7fd83 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -25,6 +25,7 @@ struct vm_fault;
#define IOMAP_MAPPED 0x03 /* blocks allocated at @addr */
#define IOMAP_UNWRITTEN 0x04 /* blocks allocated at @addr in unwritten state */
#define IOMAP_INLINE 0x05 /* data inline in the inode */
+#define IOMAP_COW 0x06 /* copy data from srcmap before writing */
/*
* Flags for all iomap mappings:
@@ -102,7 +103,8 @@ struct iomap_ops {
* The actual length is returned in iomap->length.
*/
int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
- unsigned flags, struct iomap *iomap);
+ unsigned flags, struct iomap *iomap,
+ struct iomap *srcmap);
/*
* Commit and/or unreserve space previous allocated using iomap_begin.
--
2.16.4
