btrfs: print checksum type and implementation at mount time

Per user request, print the checksum type and implementation at mount
time among the messages. The checksum is user configurable and the
actual crypto implementation is useful to see for performance reasons.
The same information is also available after mount in
/sys/fs/FSID/checksum file.

Example:

  [25.323662] BTRFS info (device vdb): using sha256 (sha256-generic) checksum algorithm

Link: https://github.com/kdave/btrfs-progs/issues/483
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 4f51491..243bd7b 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2425,6 +2425,9 @@ static int btrfs_init_csum_hash(struct btrfs_fs_info *fs_info, u16 csum_type)
 
        fs_info->csum_shash = csum_shash;
 
+       btrfs_info(fs_info, "using %s (%s) checksum algorithm",
+                       btrfs_super_csum_name(csum_type),
+                       crypto_shash_driver_name(csum_shash));
        return 0;
 }