On Mon, Mar 28, 2022 at 03:41:47PM -0400, Sasha Levin wrote:
From: Omar Sandoval osandov@fb.com
[ Upstream commit e331f6b19f8adde2307588bb325ae5de78617c20 ]
btrfs_csum_one_bio() loops over each filesystem block in the bio while keeping a cursor of its current logical position in the file in order to look up the ordered extent to add the checksums to. However, this doesn't make much sense for compressed extents, as a sector on disk does not correspond to a sector of decompressed file data. It happens to work because:
- the compressed bio always covers one ordered extent
- the size of the bio is always less than the size of the ordered extent
However, the second point will not always be true for encoded writes.
Let's add a boolean parameter to btrfs_csum_one_bio() to indicate that it can assume that the bio only covers one ordered extent. Since we're already changing the signature, let's get rid of the contig parameter and make it implied by the offset parameter, similar to the change we recently made to btrfs_lookup_bio_sums(). Additionally, let's rename nr_sectors to blockcount to make it clear that it's the number of filesystem blocks, not the number of 512-byte sectors.
Reviewed-by: Josef Bacik josef@toxicpanda.com Reviewed-by: Nikolay Borisov nborisov@suse.com Signed-off-by: Omar Sandoval osandov@fb.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org
fs/btrfs/compression.c | 2 +- fs/btrfs/ctree.h | 2 +- fs/btrfs/file-item.c | 37 +++++++++++++++++-------------------- fs/btrfs/inode.c | 8 ++++---- 4 files changed, 23 insertions(+), 26 deletions(-)
Hi, Sasha,
This patch doesn't fix a real bug, so it should be dropped from both 5.16 and 5.17.
Thanks!