>From : Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
This allows us to have an in-kernel copy mechanism that avoids frequent
switches between kernel and user space. This is especially useful so
NFSD can support server-side copies.
The default (flags=0) means to first attempt copy acceleration, but use
the pagecache if that fails.
I moved the rw_verify_area() calls into the fallback code since some
filesystems can handle reflinking a large range.
Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Reviewed-by: Padraig Brady <P@xxxxxxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
fs/read_write.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/fs/read_write.c b/fs/read_write.c
index 97c15ca..6f73af1 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1354,8 +1354,7 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
if (!(file_in->f_mode & FMODE_READ) ||
!(file_out->f_mode & FMODE_WRITE) ||
- (file_out->f_flags & O_APPEND) ||
- !file_out->f_op->copy_file_range)
+ (file_out->f_flags & O_APPEND))
return -EBADF;
/* this could be relaxed once a method supports cross-fs copies */
@@ -1369,8 +1368,14 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
if (ret)
return ret;
- ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out, pos_out,
- len, flags);
+ ret = -EOPNOTSUPP;
+ if (file_out->f_op->copy_file_range)
+ ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out,
+ pos_out, len, flags);
+ if (ret == -EOPNOTSUPP)
+ ret = do_splice_direct(file_in, &pos_in, file_out, &pos_out,
+ len > MAX_RW_COUNT ? MAX_RW_COUNT : len, 0);
+
if (ret > 0) {
fsnotify_access(file_in);
add_rchar(current, ret);
--
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