Re: [PATCH 5/5] btrfs: add no_mtime flag to btrfs-extent-same

David Sterba
2015-06-23T15:11:58Z

On Mon, Jun 22, 2015 at 03:47:42PM -0700, Mark Fasheh wrote:
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -87,7 +87,8 @@ struct btrfs_ioctl_received_subvol_args_32 {
>
>
> static int btrfs_clone(struct inode *src, struct inode *inode,
> - u64 off, u64 olen, u64 olen_aligned, u64 destoff);
> + u64 off, u64 olen, u64 olen_aligned, u64 destoff,
> + int no_mtime);

Please make it 'flags' and pass the verified flags directly.

> /* Mask out flags that are inappropriate for the given type of inode. */
> static inline __u32 btrfs_mask_flags(umode_t mode, __u32 flags)
> @@ -2974,7 +2975,7 @@ static int extent_same_check_offsets(struct inode *inode, u64 off, u64 *plen,
> }
>
> static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
> - struct inode *dst, u64 dst_loff)
> + struct inode *dst, u64 dst_loff, int no_mtime)
> {
> int ret;
> u64 len = olen;
> @@ -3054,7 +3055,8 @@ static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
> /* pass original length for comparison so we stay within i_size */
> ret = btrfs_cmp_data(src, loff, dst, dst_loff, olen, &cmp);
> if (ret == 0)
> - ret = btrfs_clone(src, dst, loff, olen, len, dst_loff);
> + ret = btrfs_clone(src, dst, loff, olen, len, dst_loff,
> + no_mtime);
>
> if (same_inode)
> unlock_extent(&BTRFS_I(src)->io_tree, same_lock_start,
> @@ -3088,6 +3090,7 @@ static long btrfs_ioctl_file_extent_same(struct file *file,
> u64 bs = BTRFS_I(src)->root->fs_info->sb->s_blocksize;
> bool is_admin = capable(CAP_SYS_ADMIN);
> u16 count;
> + int no_mtime = 0;
>
> if (!(file->f_mode & FMODE_READ))
> return -EINVAL;
> @@ -3139,6 +3142,12 @@ static long btrfs_ioctl_file_extent_same(struct file *file,
> if (!S_ISREG(src->i_mode))
> goto out;
>
> + ret = -EINVAL;
> + if (same->flags & ~BTRFS_SAME_FLAGS)
> + goto out;
> + if (same->flags & BTRFS_SAME_NO_MTIME)
> + no_mtime = 1;
> +
> /* pre-format output fields to sane values */
> for (i = 0; i < count; i++) {
> same->info[i].bytes_deduped = 0ULL;
> @@ -3164,7 +3173,8 @@ static long btrfs_ioctl_file_extent_same(struct file *file,
> info->status = -EACCES;
> } else {
> info->status = btrfs_extent_same(src, off, len, dst,
> - info->logical_offset);
> + info->logical_offset,
> + no_mtime);
> if (info->status == 0)
> info->bytes_deduped += len;
> }
> @@ -3219,13 +3229,17 @@ static int clone_finish_inode_update(struct btrfs_trans_handle *trans,
> struct inode *inode,
> u64 endoff,
> const u64 destoff,
> - const u64 olen)
> + const u64 olen,
> + int no_mtime)
> {
> struct btrfs_root *root = BTRFS_I(inode)->root;
> int ret;
>
> inode_inc_iversion(inode);
> - inode->i_mtime = inode->i_ctime = CURRENT_TIME;
> + if (no_mtime)
> + inode->i_ctime = CURRENT_TIME;
> + else
> + inode->i_mtime = inode->i_ctime = CURRENT_TIME;
> /*
> * We round up to the block size at eof when determining which
> * extents to clone above, but shouldn't round up the file size.
> @@ -3316,7 +3330,7 @@ static void clone_update_extent_map(struct inode *inode,
> */
> static int btrfs_clone(struct inode *src, struct inode *inode,
> const u64 off, const u64 olen, const u64 olen_aligned,
> - const u64 destoff)
> + const u64 destoff, int no_mtime)
> {
> struct btrfs_root *root = BTRFS_I(inode)->root;
> struct btrfs_path *path = NULL;
> @@ -3640,7 +3654,7 @@ process_slot:
> root->sectorsize);
> ret = clone_finish_inode_update(trans, inode,
> last_dest_end,
> - destoff, olen);
> + destoff, olen, no_mtime);
> if (ret)
> goto out;
> if (new_key.offset + datal >= destoff + len)
> @@ -3678,7 +3692,7 @@ process_slot:
> clone_update_extent_map(inode, trans, NULL, last_dest_end,
> destoff + len - last_dest_end);
> ret = clone_finish_inode_update(trans, inode, destoff + len,
> - destoff, olen);
> + destoff, olen, no_mtime);
> }
>
> out:
> @@ -3808,7 +3822,7 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
> btrfs_double_extent_lock(src, off, inode, destoff, len);
> }
>
> - ret = btrfs_clone(src, inode, off, olen, len, destoff);
> + ret = btrfs_clone(src, inode, off, olen, len, destoff, 0);
>
> if (same_inode) {
> u64 lock_start = min_t(u64, off, destoff);
> diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
> index b6dec05..beeb51c 100644
> --- a/include/uapi/linux/btrfs.h
> +++ b/include/uapi/linux/btrfs.h

> +#define BTRFS_SAME_NO_MTIME 0x1
> +#define BTRFS_SAME_FLAGS (BTRFS_SAME_NO_MTIME)

The naming scheme used eg. for the send flags:

BTRFS_SEND_FLAG_MASK
BTRFS_SEND_FLAG_NO_FILE_DATA

So I suggest to follow it:

BTRFS_SAME_FLAG_MASK
BTRFS_SAME_FLAG_NO_MTIME

Though I'd rather see it named it with BTRFS_EXTENT_SAME_ prefix so it
(almost ...) matches the ioctl name (and is greppable).

This is going to be in a public interface so the naming is important.