2017-08-27 23:06 GMT+03:00 Timofey Titovets <nefelim4ag@xxxxxxxxx>:
> At now btrfs_dedupe_file_range() restricted to 16MiB range for
> limit locking time and memory requirement for dedup ioctl()
>
> For too big input rage code silently set range to 16MiB
>
> Let's remove that restriction by do iterating over dedup range.
> That's backward compatible and will not change anything for request
> less then 16MiB.
>
> Signed-off-by: Timofey Titovets <nefelim4ag@xxxxxxxxx>
> ---
> fs/btrfs/ioctl.c | 22 ++++++++++++++++++----
> 1 file changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index ae8fbf9d3de2..7e77d192776f 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -3226,11 +3226,9 @@ ssize_t btrfs_dedupe_file_range(struct file *src_file, u64 loff, u64 olen,
> struct inode *src = file_inode(src_file);
> struct inode *dst = file_inode(dst_file);
> u64 bs = BTRFS_I(src)->root->fs_info->sb->s_blocksize;
> + u64 i, tail_len, chunk_count;
> ssize_t res;
>
> - if (olen > BTRFS_MAX_DEDUPE_LEN)
> - olen = BTRFS_MAX_DEDUPE_LEN;
> -
> if (WARN_ON_ONCE(bs < PAGE_SIZE)) {
> /*
> * Btrfs does not support blocksize < page_size. As a
> @@ -3240,7 +3238,23 @@ ssize_t btrfs_dedupe_file_range(struct file *src_file, u64 loff, u64 olen,
> return -EINVAL;
> }
>
> - res = btrfs_extent_same(src, loff, olen, dst, dst_loff);
> + tail_len = olen % BTRFS_MAX_DEDUPE_LEN;
> + chunk_count = div_u64(olen, BTRFS_MAX_DEDUPE_LEN);
> +
> + for (i = 0; i < chunk_count; i++) {
> + res = btrfs_extent_same(src, loff, BTRFS_MAX_DEDUPE_LEN,
> + dst, dst_loff);
> + if (res)
> + return res;
> +
> + loff += BTRFS_MAX_DEDUPE_LEN;
> + dst_loff += BTRFS_MAX_DEDUPE_LEN;
> + }
> +
> + if (tail_len > 0)
> + res = btrfs_extent_same(src, loff, tail_len,
> + dst, dst_loff);
> +
> if (res)
> return res;
> return olen;
> --
> 2.14.1
P.S.
Also, if that acceptable, it's possible to decrease BTRFS_MAX_DEDUPE_LEN
to 1MiB or 128KiB, if inode use compression to make
btrfs_extent_same() more time/cpu/lock/io сheap
--
Have a nice day,
Timofey.
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