From: Filipe Manana fdmanana@suse.com
commit 831d2fa25ab8e27592b1b0268dae6f2dfaf7cc43 upstream.
Since btrfs was migrated to use the generic VFS helpers for clone and deduplication, it stopped allowing for the last block of a file to be deduplicated when the source file size is not sector size aligned (when eof is somewhere in the middle of the last block). There are two reasons for that:
1) The generic code always rounds down, to a multiple of the block size, the range's length for deduplications. This means we end up never deduplicating the last block when the eof is not block size aligned, even for the safe case where the destination range's end offset matches the destination file's size. That rounding down operation is done at generic_remap_check_len();
2) Because of that, the btrfs specific code does not expect anymore any non-aligned range length's for deduplication and therefore does not work if such nona-aligned length is given.
This patch addresses that second part, and it depends on a patch that fixes generic_remap_check_len(), in the VFS, which was submitted ealier and has the following subject:
"fs: allow deduplication of eof block into the end of the destination file"
These two patches address reports from users that started seeing lower deduplication rates due to the last block never being deduplicated when the file size is not aligned to the filesystem's block size.
Link: https://lore.kernel.org/linux-btrfs/2019-1576167349.500456@svIo.N5dq.dFFD/ CC: stable@vger.kernel.org # 5.1+ Reviewed-by: Josef Bacik josef@toxicpanda.com Signed-off-by: Filipe Manana fdmanana@suse.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/btrfs/ioctl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -3243,6 +3243,7 @@ static void btrfs_double_extent_lock(str static int btrfs_extent_same_range(struct inode *src, u64 loff, u64 len, struct inode *dst, u64 dst_loff) { + const u64 bs = BTRFS_I(src)->root->fs_info->sb->s_blocksize; int ret;
/* @@ -3250,7 +3251,7 @@ static int btrfs_extent_same_range(struc * source range to serialize with relocation. */ btrfs_double_extent_lock(src, loff, dst, dst_loff, len); - ret = btrfs_clone(src, dst, loff, len, len, dst_loff, 1); + ret = btrfs_clone(src, dst, loff, len, ALIGN(len, bs), dst_loff, 1); btrfs_double_extent_unlock(src, loff, dst, dst_loff, len);
return ret;