[RFC PATCH 2/3] ceph: parallelize all copy-from requests in copy_file_range

Luis Henriques
2020-01-27T16:43:36Z

Right now the copy_file_range syscall serializes all the OSDs 'copy-from'
operations, waiting for each request to complete before sending the next
one. This patch modifies copy_file_range so that all the 'copy-from'
operations are sent in bulk and waits for its completion at the end. This
will allow significant speed-ups, specially when sending requests for
different target OSDs.

Signed-off-by: Luis Henriques <lhenriques@suse.com>
---
fs/ceph/file.c | 38 +++++++++++++++++++++++++++++++--
include/linux/ceph/osd_client.h | 2 ++
net/ceph/osd_client.c | 1 +
3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 1e6cdf2dfe90..5d8f0ba11719 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -1931,6 +1931,28 @@ static int is_file_size_ok(struct inode *src_inode, struct inode *dst_inode,
return 0;
}

+static int wait_copy_from_reqs(struct list_head *osd_reqs)
+{
+ struct ceph_osd_request *req;
+ int ret = 0, err;
+
+ while (!list_empty(osd_reqs)) {
+ req = list_first_entry(osd_reqs,
+ struct ceph_osd_request,
+ r_copy_item);
+ list_del_init(&req->r_copy_item);
+ err = ceph_osdc_wait_request(req->r_osdc, req);
+ if (err) {
+ if (!ret)
+ ret = err;
+ dout("copy request failed (err=%d)\n", err);
+ }
+ ceph_osdc_put_request(req);
+ }
+
+ return ret;
+}
+
static ssize_t __ceph_copy_file_range(struct file *src_file, loff_t src_off,
struct file *dst_file, loff_t dst_off,
size_t len, unsigned int flags)
@@ -1943,12 +1965,14 @@ static ssize_t __ceph_copy_file_range(struct file *src_file, loff_t src_off,
struct ceph_fs_client *src_fsc = ceph_inode_to_client(src_inode);
struct ceph_object_locator src_oloc, dst_oloc;
struct ceph_object_id src_oid, dst_oid;
+ struct ceph_osd_request *req;
loff_t endoff = 0, size;
ssize_t ret = -EIO;
u64 src_objnum, dst_objnum, src_objoff, dst_objoff;
u32 src_objlen, dst_objlen, object_size;
int src_got = 0, dst_got = 0, err, dirty;
bool do_final_copy = false;
+ LIST_HEAD(osd_reqs);

if (src_inode->i_sb != dst_inode->i_sb) {
struct ceph_fs_client *dst_fsc = ceph_inode_to_client(dst_inode);
@@ -2097,7 +2121,7 @@ static ssize_t __ceph_copy_file_range(struct file *src_file, loff_t src_off,
ceph_oid_printf(&dst_oid, "%llx.%08llx",
dst_ci->i_vino.ino, dst_objnum);
/* Do an object remote copy */
- err = ceph_osdc_copy_from(
+ req = ceph_osdc_copy_from_nowait(
&src_fsc->client->osdc,
src_ci->i_vino.snap, 0,
&src_oid, &src_oloc,
@@ -2108,7 +2132,8 @@ static ssize_t __ceph_copy_file_range(struct file *src_file, loff_t src_off,
CEPH_OSD_OP_FLAG_FADVISE_DONTNEED,
dst_ci->i_truncate_seq, dst_ci->i_truncate_size,
CEPH_OSD_COPY_FROM_FLAG_TRUNCATE_SEQ);
- if (err) {
+ if (IS_ERR(req)) {
+ err = PTR_ERR(req);
if (err == -EOPNOTSUPP) {
src_fsc->have_copy_from2 = false;
pr_notice("OSDs don't support 'copy-from2'; "
@@ -2117,14 +2142,23 @@ static ssize_t __ceph_copy_file_range(struct file *src_file, loff_t src_off,
dout("ceph_osdc_copy_from returned %d\n", err);
if (!ret)
ret = err;
+ /* wait for all queued requests */
+ wait_copy_from_reqs(&osd_reqs);
goto out_caps;
}
+ list_add(&req->r_copy_item, &osd_reqs);
len -= object_size;
src_off += object_size;
dst_off += object_size;
ret += object_size;
}

+ err = wait_copy_from_reqs(&osd_reqs);
+ if (err) {
+ if (!ret)
+ ret = err;
+ goto out_caps;
+ }
if (len)
/* We still need one final local copy */
do_final_copy = true;
diff --git a/include/linux/ceph/osd_client.h b/include/linux/ceph/osd_client.h
index 7916a178d137..2b4a14bc6154 100644
--- a/include/linux/ceph/osd_client.h
+++ b/include/linux/ceph/osd_client.h
@@ -210,6 +210,8 @@ struct ceph_osd_request {
u64 r_data_offset; /* ditto */
bool r_linger; /* don't resend on failure */

+ struct list_head r_copy_item; /* used for copy-from operations */
+
/* internal */
unsigned long r_stamp; /* jiffies, send or check time */
unsigned long r_start_stamp; /* jiffies */
diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 7f984532f37c..16f38c3d606e 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -531,6 +531,7 @@ static void request_init(struct ceph_osd_request *req)
RB_CLEAR_NODE(&req->r_node);
RB_CLEAR_NODE(&req->r_mc_node);
INIT_LIST_HEAD(&req->r_private_item);
+ INIT_LIST_HEAD(&req->r_copy_item);

target_init(&req->r_t);
}