On Mon, Oct 15, 2018 at 11:47 PM 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 length is smaller than the
> object size.
>
> Signed-off-by: Luis Henriques <lhenriques@xxxxxxxx>
> ---
> fs/ceph/file.c | 294 ++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 293 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index 92ab20433682..0942f45995a1 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>
> @@ -1829,6 +1830,297 @@ static long ceph_fallocate(struct file *file, int mode,
> return ret;
> }
>
> +/*
> + * This function tries to get FILE_WR capabilities for dst_ci and FILE_RD for
> + * src_ci. Two attempts are made to obtain both caps, and an error is return if
> + * this fails; zero is returned on success.
> + */
> +static int get_rd_wr_caps(struct ceph_inode_info *src_ci,
> + loff_t src_endoff, int *src_got,
> + struct ceph_inode_info *dst_ci,
> + loff_t dst_endoff, int *dst_got)
> +{
> + int ret = 0;
> + bool retrying = false;
> +
> +retry_caps:
> + ret = ceph_get_caps(dst_ci, CEPH_CAP_FILE_WR, CEPH_CAP_FILE_BUFFER,
> + dst_endoff, dst_got, NULL);
> + if (ret < 0)
> + return ret;
> +
> + /*
> + * Since we're already holding the FILE_WR capability for the dst 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.
> + */
> + ret = ceph_try_get_caps(src_ci, CEPH_CAP_FILE_RD, CEPH_CAP_FILE_SHARED,
> + false, src_got);
> + if (ret <= 0) {
> + /* Start by dropping dst_ci caps and getting src_ci caps */
> + ceph_put_cap_refs(dst_ci, *dst_got);
> + if (retrying) {
> + if (!ret)
> + /* ceph_try_get_caps masks EAGAIN */
> + ret = -EAGAIN;
> + return ret;
> + }
> + ret = ceph_get_caps(src_ci, CEPH_CAP_FILE_RD,
> + CEPH_CAP_FILE_SHARED, src_endoff,
> + src_got, NULL);
> + if (ret < 0)
> + return ret;
> + /*... drop src_ci caps too, and retry */
> + ceph_put_cap_refs(src_ci, *src_got);
> + retrying = true;
> + goto retry_caps;
> + }
> + return ret;
> +}
> +
> +static void put_rd_wr_caps(struct ceph_inode_info *src_ci, int src_got,
> + struct ceph_inode_info *dst_ci, int dst_got)
> +{
> + ceph_put_cap_refs(src_ci, src_got);
> + ceph_put_cap_refs(dst_ci, dst_got);
> +}
> +
> +/*
> + * This function does several size-related checks, returning an error if:
> + * - source file is smaller than off+len
> + * - destination file size is not OK (inode_newsize_ok())
> + * - max bytes quotas is exceeded
> + */
> +static int is_file_size_ok(struct inode *src_inode, struct inode *dst_inode,
> + loff_t src_off, loff_t dst_off, size_t len)
> +{
> + loff_t size, endoff;
> +
> + size = i_size_read(src_inode);
> + /*
> + * Don't copy beyond source file EOF. Instead of simply setting length
> + * 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) {
> + dout("Copy beyond EOF (%llu + %ld > %llu)\n",
> + src_off, len, size);
> + return -EOPNOTSUPP;
> + }
> + size = i_size_read(dst_inode);
> +
> + endoff = dst_off + len;
> + if (inode_newsize_ok(dst_inode, endoff))
> + return -EOPNOTSUPP;
> +
> + if (ceph_quota_is_max_bytes_exceeded(dst_inode, endoff))
> + return -EDQUOT;
> +
> + return 0;
> +}
> +
> +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_cap_flush *prealloc_cf;
> + struct ceph_object_locator src_oloc, dst_oloc;
> + struct ceph_object_id src_oid, dst_oid;
> + 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;
> +
> + if (src_inode == dst_inode)
> + return -EINVAL;
> + if (ceph_snap(dst_inode) != CEPH_NOSNAP)
> + return -EROFS;
> +
> + /*
> + * Some of the checks below will return -EOPNOTSUPP, which will force a
> + * fallback to the default VFS copy_file_range implementation. This is
> + * desirable in several cases (for ex, the 'len' is smaller than the
> + * size of the objects, or in cases where that would be more
> + * efficient).
> + */
> +
> + if ((src_ci->i_layout.stripe_unit != dst_ci->i_layout.stripe_unit) ||
> + (src_ci->i_layout.stripe_count != dst_ci->i_layout.stripe_count) ||
> + (src_ci->i_layout.object_size != dst_ci->i_layout.object_size))
> + return -EOPNOTSUPP;
> +
> + if (len < src_ci->i_layout.object_size)
> + return -EOPNOTSUPP; /* no remote copy will be done */
> +
> + 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;
> +
> + /*
> + * We need FILE_WR caps for dst_ci and FILE_RD for src_ci 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.
> + */
> + err = get_rd_wr_caps(src_ci, (src_off + len), &src_got,
> + dst_ci, (dst_off + len), &dst_got);
> + if (err < 0) {
> + dout("get_rd_wr_caps returned %d\n", err);
> + ret = -EOPNOTSUPP;
> + goto out;
> + }
> +
> + ret = is_file_size_ok(src_inode, dst_inode, src_off, dst_off, len);
> + if (ret < 0)
> + goto out_caps;
> +
> + size = i_size_read(dst_inode);
> + endoff = dst_off + len;
> +
> + /* Drop dst file cached pages */
> + ret = invalidate_inode_pages2_range(dst_inode->i_mapping,
> + dst_off >> PAGE_SHIFT,
> + endoff >> PAGE_SHIFT);
> + if (ret < 0) {
> + dout("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);
> +
> + ceph_calc_file_object_mapping(&src_ci->i_layout, src_off,
> + src_ci->i_layout.object_size,
> + &src_objnum, &src_objoff, &src_objlen);
> + ceph_calc_file_object_mapping(&dst_ci->i_layout, dst_off,
> + dst_ci->i_layout.object_size,
> + &dst_objnum, &dst_objoff, &dst_objlen);
> + /* object-level offsets need to the same */
> + if (src_objoff != dst_objoff) {
> + ret = -EOPNOTSUPP;
> + goto out_caps;
> + }
> +
> + /*
> + * Do a manual copy if the object offset isn't object aligned.
> + * 'src_objlen' contains the bytes left until the end of the object,
> + * starting at the src_off
> + */
> + if (src_objoff) {
> + /*
> + * we need to temporarily drop all caps as we'll be calling
> + * {read,write}_iter, which will get caps again.
> + */
> + put_rd_wr_caps(src_ci, src_got, dst_ci, dst_got);
> + ret = do_splice_direct(src_file, &src_off, dst_file,
> + &dst_off, src_objlen, flags);
> + if (ret < 0) {
> + dout("do_splice_direct returned %d\n", err);
> + goto out;
> + }
> + len -= ret;
> + err = get_rd_wr_caps(src_ci, (src_off + len),
> + &src_got, dst_ci,
> + (dst_off + len), &dst_got);
> + if (err < 0)
> + goto out;
> + err = is_file_size_ok(src_inode, dst_inode,
> + src_off, dst_off, len);
> + if (err < 0)
> + goto out_caps;
> + }
> + object_size = src_ci->i_layout.object_size;
> + while (len >= object_size) {
> + ceph_calc_file_object_mapping(&src_ci->i_layout, src_off,
> + object_size, &src_objnum,
> + &src_objoff, &src_objlen);
> + ceph_calc_file_object_mapping(&dst_ci->i_layout, dst_off,
> + object_size, &dst_objnum,
> + &dst_objoff, &dst_objlen);
> + ceph_oid_init(&src_oid);
> + ceph_oid_printf(&src_oid, "%llx.%08llx",
> + src_ci->i_vino.ino, src_objnum);
> + ceph_oid_init(&dst_oid);
> + ceph_oid_printf(&dst_oid, "%llx.%08llx",
> + dst_ci->i_vino.ino, dst_objnum);
> + /* Do an object remote copy */
> + err = ceph_osdc_copy_from(
> + &ceph_inode_to_client(src_inode)->client->osdc,
> + src_ci->i_vino.snap, 0,
> + &src_oid, &src_oloc,
> + CEPH_OSD_OP_FLAG_FADVISE_SEQUENTIAL |
> + CEPH_OSD_OP_FLAG_FADVISE_NOCACHE,
> + &dst_oid, &dst_oloc,
> + CEPH_OSD_OP_FLAG_FADVISE_SEQUENTIAL |
> + CEPH_OSD_OP_FLAG_FADVISE_DONTNEED, 0);
> + if (err) {
> + dout("ceph_osdc_copy_from returned %d\n", err);
> + if (!ret)
> + ret = err;
> + goto out_caps;
> + }
> + len -= object_size;
> + src_off += object_size;
> + dst_off += object_size;
> + ret += object_size;
> + }
> +
> + if (len)
> + /* We still need one final local copy */
> + do_final_copy = true;
> +
> + file_update_time(dst_file);
> + if (endoff > size) {
> + int caps_flags = 0;
> +
> + /* Let the MDS know about dst file size change */
> + 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);
> + }
> + /* Mark Fw dirty */
> + 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, &prealloc_cf);
> + spin_unlock(&dst_ci->i_ceph_lock);
> + if (dirty)
> + __mark_inode_dirty(dst_inode, dirty);
> +
> +out_caps:
> + put_rd_wr_caps(src_ci, src_got, dst_ci, dst_got);
> +
> + if (do_final_copy) {
> + err = do_splice_direct(src_file, &src_off, dst_file,
> + &dst_off, len, flags);
> + if (err < 0) {
> + dout("do_splice_direct returned %d\n", err);
> + goto out;
> + }
> + len -= err;
> + ret += err;
> + }
> +
> +out:
> + ceph_free_cap_flush(prealloc_cf);
> +
> + return ret;
> +}
> +
> const struct file_operations ceph_file_fops = {
> .open = ceph_open,
> .release = ceph_release,
> @@ -1844,5 +2136,5 @@ 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,
> };
> -
Looks good to me
Regards
Yan, Zheng
