Re: [PATCH v2 07/10] iomap: Introduce iomap_apply2() for operations on two files
From: Darrick J. Wong
Date: Thu Feb 25 2021 - 23:15:55 EST
On Fri, Feb 26, 2021 at 08:20:27AM +0800, Shiyang Ruan wrote:
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Some operations, such as comparing a range of data in two files under
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fsdax mode, requires nested iomap_open()/iomap_end() on two file. Thus,
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we introduce iomap_apply2() to accept arguments from two files and
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iomap_actor2_t for actions on two files.
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Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>
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---
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fs/iomap/apply.c | 51 +++++++++++++++++++++++++++++++++++++++++++
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include/linux/iomap.h | 7 +++++-
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2 files changed, 57 insertions(+), 1 deletion(-)
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diff --git a/fs/iomap/apply.c b/fs/iomap/apply.c
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index 26ab6563181f..fd2f8bde5791 100644
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--- a/fs/iomap/apply.c
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+++ b/fs/iomap/apply.c
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@@ -97,3 +97,54 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
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return written ? written : ret;
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}
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+
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+loff_t
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+iomap_apply2(struct inode *ino1, loff_t pos1, struct inode *ino2, loff_t pos2,
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+ loff_t length, unsigned int flags, const struct iomap_ops *ops,
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+ void *data, iomap_actor2_t actor)
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+{
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+ struct iomap smap = { .type = IOMAP_HOLE };
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+ struct iomap dmap = { .type = IOMAP_HOLE };
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+ loff_t written = 0, ret;
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+
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+ ret = ops->iomap_begin(ino1, pos1, length, 0, &smap, NULL);
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+ if (ret)
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+ goto out_src;
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+ if (WARN_ON(smap.offset > pos1)) {
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+ written = -EIO;
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+ goto out_src;
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+ }
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+ if (WARN_ON(smap.length == 0)) {
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+ written = -EIO;
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+ goto out_src;
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+ }
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+
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+ ret = ops->iomap_begin(ino2, pos2, length, 0, &dmap, NULL);
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+ if (ret)
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+ goto out_dest;
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+ if (WARN_ON(dmap.offset > pos2)) {
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+ written = -EIO;
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+ goto out_dest;
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+ }
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+ if (WARN_ON(dmap.length == 0)) {
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+ written = -EIO;
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+ goto out_dest;
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+ }
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+
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+ /* make sure extent length of two file is equal */
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+ if (WARN_ON(smap.length != dmap.length)) {
Why not set smap.length and dmap.length to min(smap.length, dmap.length) ?
--D
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+ written = -EIO;
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+ goto out_dest;
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+ }
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+
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+ written = actor(ino1, pos1, ino2, pos2, length, data, &smap, &dmap);
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+
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+out_dest:
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+ if (ops->iomap_end)
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+ ret = ops->iomap_end(ino2, pos2, length, 0, 0, &dmap);
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+out_src:
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+ if (ops->iomap_end)
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+ ret = ops->iomap_end(ino1, pos1, length, 0, 0, &smap);
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+
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+ return ret;
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+}
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diff --git a/include/linux/iomap.h b/include/linux/iomap.h
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index 5bd3cac4df9c..913f98897a77 100644
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--- a/include/linux/iomap.h
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+++ b/include/linux/iomap.h
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@@ -148,10 +148,15 @@ struct iomap_ops {
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*/
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typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len,
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void *data, struct iomap *iomap, struct iomap *srcmap);
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-
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+typedef loff_t (*iomap_actor2_t)(struct inode *ino1, loff_t pos1,
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+ struct inode *ino2, loff_t pos2, loff_t len, void *data,
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+ struct iomap *smap, struct iomap *dmap);
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loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length,
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unsigned flags, const struct iomap_ops *ops, void *data,
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iomap_actor_t actor);
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+loff_t iomap_apply2(struct inode *ino1, loff_t pos1, struct inode *ino2,
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+ loff_t pos2, loff_t length, unsigned int flags,
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+ const struct iomap_ops *ops, void *data, iomap_actor2_t actor);
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ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
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const struct iomap_ops *ops);
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--
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2.30.1
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