When copying up within the same fs, try to use f_op->copy_file_range().
This becomes very efficient when lower and upper are on the same fs
with file reflink support.
Tested correct behavior when lower and upper are on:
1. same ext4 (copy)
2. same xfs + reflink patches + mkfs.xfs (copy)
3. same xfs + reflink patches + mkfs.xfs -m reflink=1 (clone)
4. different xfs + reflink patches + mkfs.xfs -m reflink=1 (copy)
Verified that all the overlay xfstests pass in the 'same xfs+reflink'
setup.
For comparison, on my laptop, xfstest overlay/001 (copy up of large
sparse files) takes less than 1 second in the xfs reflink setup vs.
25 seconds on the rest of the setups.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/overlayfs/copy_up.c | 28 +++++++++++++++++++++++++---
1 file changed, 25 insertions(+), 3 deletions(-)
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 43fdc27..400567b 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -121,6 +121,7 @@ static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len)
struct file *new_file;
loff_t old_pos = 0;
loff_t new_pos = 0;
+ int try_copy_file = 0;
int error = 0;
if (len == 0)
@@ -136,6 +137,13 @@ static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len)
goto out_fput;
}
+ /*
+ * When copying up within the same fs, try to use fs's copy_file_range
+ */
+ if (file_inode(old_file)->i_sb == file_inode(new_file)->i_sb) {
+ try_copy_file = (new_file->f_op->copy_file_range != NULL);
+ }
+
/* FIXME: copy up sparse files efficiently */
while (len) {
size_t this_len = OVL_COPY_UP_CHUNK_SIZE;
@@ -149,9 +157,23 @@ static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len)
break;
}
- bytes = do_splice_direct(old_file, &old_pos,
- new_file, &new_pos,
- this_len, SPLICE_F_MOVE);
+ if (try_copy_file) {
+ bytes = new_file->f_op->copy_file_range(
+ old_file, old_pos,
+ new_file, new_pos,
+ len, 0);
+ if (bytes == -EOPNOTSUPP) {
+ try_copy_file = 0;
+ continue;
+ } else if (bytes > 0) {
+ old_pos += bytes;
+ new_pos += bytes;
+ }
+ } else {
+ bytes = do_splice_direct(old_file, &old_pos,
+ new_file, &new_pos,
+ this_len, SPLICE_F_MOVE);
+ }
if (bytes <= 0) {
error = bytes;
break;
--
2.7.4
--
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