ceph: add destination file data sync before doing any remote copy

If we try to copy into a file that was just written, any data that is
remote copied will be overwritten by our buffered writes once they are
flushed.  When this happens, the call to invalidate_inode_pages2_range
will also return a -EBUSY error.

This patch fixes this by also sync'ing the destination file before
starting any copy.

Fixes: 503f82a9932d ("ceph: support copy_file_range file operation")
Signed-off-by: Luis Henriques <lhenriques@suse.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 27cad84..189df66 100644 (file)
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -1931,10 +1931,17 @@ static ssize_t ceph_copy_file_range(struct file *src_file, loff_t src_off,
        if (!prealloc_cf)
                return -ENOMEM;
 
-       /* Start by sync'ing the source file */
+       /* Start by sync'ing the source and destination files */
        ret = file_write_and_wait_range(src_file, src_off, (src_off + len));
-       if (ret < 0)
+       if (ret < 0) {
+               dout("failed to write src file (%zd)\n", ret);
+               goto out;
+       }
+       ret = file_write_and_wait_range(dst_file, dst_off, (dst_off + len));
+       if (ret < 0) {
+               dout("failed to write dst file (%zd)\n", ret);
                goto out;
+       }
 
        /*
         * We need FILE_WR caps for dst_ci and FILE_RD for src_ci as other