btrfs: don't check stripe length if the profile is not stripe based

[BUG]
When debugging calc_bio_boundaries(), I found that even for RAID1
metadata, we're following stripe length to calculate stripe boundary.

  # mkfs.btrfs -m raid1 -d raid1 /dev/test/scratch[12]
  # mount /dev/test/scratch /mnt/btrfs
  # xfs_io -f -c "pwrite 0 64K" /mnt/btrfs/file
  # umount

Above very basic operations will make calc_bio_boundaries() to report
the following result:

  submit_extent_page: r/i=1/1 file_offset=22036480 len_to_stripe_boundary=49152
  submit_extent_page: r/i=1/1 file_offset=30474240 len_to_stripe_boundary=65536
  ...
  submit_extent_page: r/i=1/1 file_offset=30523392 len_to_stripe_boundary=16384
  submit_extent_page: r/i=1/1 file_offset=30457856 len_to_stripe_boundary=16384
  submit_extent_page: r/i=5/257 file_offset=0 len_to_stripe_boundary=65536
  submit_extent_page: r/i=5/257 file_offset=65536 len_to_stripe_boundary=65536
  submit_extent_page: r/i=1/1 file_offset=30490624 len_to_stripe_boundary=49152
  submit_extent_page: r/i=1/1 file_offset=30507008 len_to_stripe_boundary=32768

Where "r/i" is the rootid and inode, 1/1 means they metadata.
The remaining names match the member used in kernel.

Even all data/metadata are using RAID1, we're still following stripe
length.

[CAUSE]
This behavior is caused by a wrong condition in btrfs_get_io_geometry():

	if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
		/* Fill using stripe_len */
		len = min_t(u64, em->len - offset, max_len);
	} else {
		len = em->len - offset;
	}

This means, only for SINGLE we will not follow stripe_len.

However for profiles like RAID1*, DUP, they don't need to bother
stripe_len.

This can lead to unnecessary bio split for RAID1*/DUP profiles, and can
even be a blockage for future zoned RAID support.

[FIX]
Introduce one single-use macro, BTRFS_BLOCK_GROUP_STRIPE_MASK, and
change the condition to only calculate the length using stripe length
for stripe based profiles.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index cafd490da072edaac683ecb11157eeae86c4a015..f463dd5b8da3d29565cdbff62acf525e9b9a6d3b 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -34,6 +34,10 @@
 #include "discard.h"
 #include "zoned.h"
 
+#define BTRFS_BLOCK_GROUP_STRIPE_MASK  (BTRFS_BLOCK_GROUP_RAID0 | \
+                                        BTRFS_BLOCK_GROUP_RAID10 | \
+                                        BTRFS_BLOCK_GROUP_RAID56_MASK)
+
 const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
        [BTRFS_RAID_RAID10] = {
                .sub_stripes    = 2,
@@ -6347,7 +6351,8 @@ int btrfs_get_io_geometry(struct btrfs_fs_info *fs_info, struct extent_map *em,
        stripe_offset = offset - stripe_offset;
        data_stripes = nr_data_stripes(map);
 
-       if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
+       /* Only stripe based profiles needs to check against stripe length. */
+       if (map->type & BTRFS_BLOCK_GROUP_STRIPE_MASK) {
                u64 max_len = stripe_len - stripe_offset;
 
                /*