On Mon, Aug 27, 2018 at 6:46 AM Luis Henriques <lhenriques@xxxxxxxx> wrote:
>
> This commit implements support for the copy_file_range syscall in cephfs.
> It is implemented using the RADOS 'copy-from' operation, which allows to
> do a remote object copy, without the need to download/upload data from/to
> the OSDs.
>
> Some manual copy may however be required if the source/destination file
> offsets aren't object aligned or if the copy lenght is smaller than the
> object size.
>
> Signed-off-by: Luis Henriques <lhenriques@xxxxxxxx>
> ---
> fs/ceph/file.c | 225 +++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 225 insertions(+)
>
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index ad0bed99b1d5..8939ec224144 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -1,5 +1,6 @@
> // SPDX-License-Identifier: GPL-2.0
> #include <linux/ceph/ceph_debug.h>
> +#include <linux/ceph/striper.h>
>
> #include <linux/module.h>
> #include <linux/sched.h>
> @@ -1820,6 +1821,229 @@ static long ceph_fallocate(struct file *file, int mode,
> 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)
> +{
> + struct inode *src_inode = file_inode(src_file);
> + struct inode *dst_inode = file_inode(dst_file);
> + struct ceph_inode_info *src_ci = ceph_inode(src_inode);
> + struct ceph_inode_info *dst_ci = ceph_inode(dst_inode);
> + struct ceph_osd_client *osdc =
> + &ceph_inode_to_client(src_inode)->client->osdc;
> + struct ceph_cap_flush *prealloc_cf;
> + struct ceph_object_locator src_oloc, dst_oloc;
> + loff_t endoff = 0;
> + loff_t size;
> + ssize_t ret = -EIO;
> + int src_got = 0;
> + int dst_got = 0;
> + bool retrying = false;
> +
> + if (src_inode == dst_inode)
> + return -EINVAL;
> + if (ceph_snap(dst_inode) != CEPH_NOSNAP)
> + return -EROFS;
> +
> + prealloc_cf = ceph_alloc_cap_flush();
> + if (!prealloc_cf)
> + return -ENOMEM;
> +
> + /* Start by sync'ing the source file */
> + ret = file_write_and_wait_range(src_file, src_off, (src_off + len));
> + if (ret < 0)
> + goto out;
> +
> + size = i_size_read(src_inode);
> + /*
> + * Don't copy beyond source file EOF. Instead of simply setting lenght
> + * to (size - src_off), just drop to VFS default implementation, as the
> + * local i_size may be stale due to other clients writing to the source
> + * inode.
> + */
> + if (src_off + len > size) {
> + ret = -EOPNOTSUPP;
> + goto out;
> + }
we should check src inode's size after getting its caps.
> + if (!len) {
> + ret = 0;
> + goto out;
> + }
> + size = i_size_read(dst_inode);
> + endoff = dst_off + len;
> + ret = inode_newsize_ok(dst_inode, endoff);
> + if (ret)
> + goto out;
> +
> + if (ceph_quota_is_max_bytes_exceeded(dst_inode, endoff)) {
> + ret = -EDQUOT;
> + goto out;
> + }
> +
> +retry_caps:
> + ret = ceph_get_caps(dst_ci, CEPH_CAP_FILE_WR, CEPH_CAP_FILE_BUFFER,
> + endoff, &dst_got, NULL);
> + if (ret < 0)
> + goto out;
> + /*
> + * We also need to get FILE_RD capabilities for source file as other
> + * clients may have dirty data in their caches. And OSDs know nothing
> + * about caps, so they can't safely do the remote object copies.
> + *
> + * However, since we're already holding the FILE_WR capability for the
> + * source file, we would risk a deadlock by using ceph_get_caps. Thus,
> + * we'll do some retry dance instead to try to get both capabilities.
> + * If everything fails, we just return -EOPNOTSUPP and fallback to the
> + * VFS default copy_file_range implementation.
> + */
> + ret = ceph_try_get_caps(src_ci, CEPH_CAP_FILE_RD, CEPH_CAP_FILE_SHARED,
> + false, &src_got);
> + if (ret <= 0) {
> + if (retrying) {
> + ret = -EOPNOTSUPP;
> + goto out_dst_caps;
> + }
> + /* Start by dropping dsc_ci caps and getting src_ci caps */
> + ceph_put_cap_refs(dst_ci, dst_got);
> + ret = ceph_get_caps(src_ci, CEPH_CAP_FILE_RD,
> + CEPH_CAP_FILE_SHARED,
> + (src_off + len), &src_got, NULL);
> + if (ret < 0) {
> + ret = -EOPNOTSUPP;
> + goto out;
> + }
> + /*... drop them too, and retry */
> + ceph_put_cap_refs(src_ci, src_got);
> + retrying = true;
> + goto retry_caps;
> + }
> +
> + /* Drop dst file cached pages */
> + ret = invalidate_inode_pages2_range(dst_inode->i_mapping,
> + dst_off >> PAGE_SHIFT,
> + endoff >> PAGE_SHIFT);
> + if (ret < 0) {
> + printk("Failed to invalidate inode pages (%ld)\n", ret);
> + ret = 0; /* XXX */
> + }
> + src_oloc.pool = src_ci->i_layout.pool_id;
> + src_oloc.pool_ns = ceph_try_get_string(src_ci->i_layout.pool_ns);
> + dst_oloc.pool = dst_ci->i_layout.pool_id;
> + dst_oloc.pool_ns = ceph_try_get_string(dst_ci->i_layout.pool_ns);
> + /*
> + * TODO: should file_start_write/file_end_write be used for the whole
> + * loop? Or any other locking?
> + */
> + while (len > 0) {
> + struct ceph_object_id src_oid, dst_oid;
> + u64 objnum, objoff;
> + u32 objlen;
> + size_t copy_len = min_t(size_t, src_ci->i_layout.object_size, len);
> + int err = 0;
> +
> + ceph_calc_file_object_mapping(&src_ci->i_layout, src_off,
> + copy_len, &objnum, &objoff,
> + &objlen);
> + ceph_oid_init(&src_oid);
> + ceph_oid_printf(&src_oid, "%llx.%08llx",
> + src_ci->i_vino.ino, objnum);
> +
> + /* Do manual copy if:
> + * - source file offset isn't object aligned, or
> + * - copy length is smaller than object size
> + */
> + if (objoff || (copy_len < src_ci->i_layout.object_size)) {
> + /* Do not copy beyond this object */
> + if (copy_len > objlen)
> + copy_len = objlen;
> + err = do_splice_direct(src_file, &src_off, dst_file,
> + &dst_off, copy_len, flags);
> + if (err < 0) {
> + ret = err;
> + goto out_caps;
> + }
> + len -= copy_len;
> + ret += copy_len;
> + continue;
> + }
> +
> + ceph_calc_file_object_mapping(&dst_ci->i_layout, dst_off,
> + copy_len, &objnum, &objoff,
> + &objlen);
> + ceph_oid_init(&dst_oid);
> + ceph_oid_printf(&dst_oid, "%llx.%08llx",
> + dst_ci->i_vino.ino, objnum);
> + /* Again... do a manual copy if:
> + * - destination file offset isn't object aligned, or
> + * - copy length is smaller than object size
> + * (although the object size should be the same for different
> + * files in the same filesystem...)
> + */
> + if (objoff || (copy_len < dst_ci->i_layout.object_size)) {
> + if (copy_len > objlen)
> + copy_len = objlen;
> + err = do_splice_direct(src_file, &src_off, dst_file,
> + &dst_off, copy_len, flags);
> + if (err < 0) {
> + ret = err;
> + goto out_caps;
> + }
> + len -= copy_len;
> + ceph_oid_destroy(&src_oid);
> + ret += copy_len;
> + continue;
> + }
> + /* Finally... do an object remote copy */
> + err = ceph_osdc_copy_from(osdc, src_ci->i_vino.snap,
> + 0, /* XXX src_ci->i_version ? */
> + &src_oid, &src_oloc,
> + CEPH_OSD_OP_FLAG_FADVISE_SEQUENTIAL|CEPH_OSD_OP_FLAG_FADVISE_WILLNEED,
> + dst_ci->i_vino.snap, &dst_oid,
> + &dst_oloc,
> + CEPH_OSD_OP_FLAG_FADVISE_SEQUENTIAL|CEPH_OSD_OP_FLAG_FADVISE_WILLNEED);
> + if (err) {
> + printk("copy_from returned an error: %d\n", err); /* XXX */
> + ret = err;
> + goto out_caps;
> + }
> + len -= copy_len;
> + src_off += copy_len;
> + dst_off += copy_len;
> + ret += copy_len;
> + ceph_oid_destroy(&src_oid);
> + ceph_oid_destroy(&dst_oid);
> + }
> + /* Let the MDS know about destination object size change */
> + if (endoff > size) {
> + int dirty;
> + int caps_flags = CHECK_CAPS_AUTHONLY;
> +
> + if (ceph_quota_is_max_bytes_approaching(dst_inode, endoff))
> + caps_flags |= CHECK_CAPS_NODELAY;
> + if (ceph_inode_set_size(dst_inode, endoff))
> + caps_flags |= CHECK_CAPS_AUTHONLY;
> + if (caps_flags)
> + ceph_check_caps(dst_ci, caps_flags, NULL);
> + spin_lock(&dst_ci->i_ceph_lock);
> + dst_ci->i_inline_version = CEPH_INLINE_NONE;
> + dirty = __ceph_mark_dirty_caps(
> + dst_ci,
> + CEPH_CAP_FILE_WR | CEPH_CAP_FILE_BUFFER,
> + &prealloc_cf);
> + spin_unlock(&dst_ci->i_ceph_lock);
> + if (dirty)
> + __mark_inode_dirty(dst_inode, dirty);
> + }
> +out_caps:
> + ceph_put_cap_refs(src_ci, src_got);
> +out_dst_caps:
> + ceph_put_cap_refs(dst_ci, dst_got);
> +out:
> + ceph_free_cap_flush(prealloc_cf);
> +
> + return ret;
> +}
> +
> const struct file_operations ceph_file_fops = {
> .open = ceph_open,
> .release = ceph_release,
> @@ -1835,5 +2059,6 @@ const struct file_operations ceph_file_fops = {
> .unlocked_ioctl = ceph_ioctl,
> .compat_ioctl = ceph_ioctl,
> .fallocate = ceph_fallocate,
> + .copy_file_range = ceph_copy_file_range,
> };
>
