[PATCH v2 07/10] iomap: Introduce iomap_apply2() for operations on two files

From: Shiyang Ruan
Date: Thu Feb 25 2021 - 19:28:02 EST


Some operations, such as comparing a range of data in two files under
fsdax mode, requires nested iomap_open()/iomap_end() on two file. Thus,
we introduce iomap_apply2() to accept arguments from two files and
iomap_actor2_t for actions on two files.

Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>
---
fs/iomap/apply.c | 51 +++++++++++++++++++++++++++++++++++++++++++
include/linux/iomap.h | 7 +++++-
2 files changed, 57 insertions(+), 1 deletion(-)

diff --git a/fs/iomap/apply.c b/fs/iomap/apply.c
index 26ab6563181f..fd2f8bde5791 100644
--- a/fs/iomap/apply.c
+++ b/fs/iomap/apply.c
@@ -97,3 +97,54 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,

return written ? written : ret;
}
+
+loff_t
+iomap_apply2(struct inode *ino1, loff_t pos1, struct inode *ino2, loff_t pos2,
+ loff_t length, unsigned int flags, const struct iomap_ops *ops,
+ void *data, iomap_actor2_t actor)
+{
+ struct iomap smap = { .type = IOMAP_HOLE };
+ struct iomap dmap = { .type = IOMAP_HOLE };
+ loff_t written = 0, ret;
+
+ ret = ops->iomap_begin(ino1, pos1, length, 0, &smap, NULL);
+ if (ret)
+ goto out_src;
+ if (WARN_ON(smap.offset > pos1)) {
+ written = -EIO;
+ goto out_src;
+ }
+ if (WARN_ON(smap.length == 0)) {
+ written = -EIO;
+ goto out_src;
+ }
+
+ ret = ops->iomap_begin(ino2, pos2, length, 0, &dmap, NULL);
+ if (ret)
+ goto out_dest;
+ if (WARN_ON(dmap.offset > pos2)) {
+ written = -EIO;
+ goto out_dest;
+ }
+ if (WARN_ON(dmap.length == 0)) {
+ written = -EIO;
+ goto out_dest;
+ }
+
+ /* make sure extent length of two file is equal */
+ if (WARN_ON(smap.length != dmap.length)) {
+ written = -EIO;
+ goto out_dest;
+ }
+
+ written = actor(ino1, pos1, ino2, pos2, length, data, &smap, &dmap);
+
+out_dest:
+ if (ops->iomap_end)
+ ret = ops->iomap_end(ino2, pos2, length, 0, 0, &dmap);
+out_src:
+ if (ops->iomap_end)
+ ret = ops->iomap_end(ino1, pos1, length, 0, 0, &smap);
+
+ return ret;
+}
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 5bd3cac4df9c..913f98897a77 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -148,10 +148,15 @@ struct iomap_ops {
*/
typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len,
void *data, struct iomap *iomap, struct iomap *srcmap);
-
+typedef loff_t (*iomap_actor2_t)(struct inode *ino1, loff_t pos1,
+ struct inode *ino2, loff_t pos2, loff_t len, void *data,
+ struct iomap *smap, struct iomap *dmap);
loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length,
unsigned flags, const struct iomap_ops *ops, void *data,
iomap_actor_t actor);
+loff_t iomap_apply2(struct inode *ino1, loff_t pos1, struct inode *ino2,
+ loff_t pos2, loff_t length, unsigned int flags,
+ const struct iomap_ops *ops, void *data, iomap_actor2_t actor);

ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
const struct iomap_ops *ops);
--
2.30.1