[PATCH v4 25/30] btrfs: reject raid5/6 fs for subpage

[Qu Wenruo <wqu@suse.com>]

Raid5/6 is not only unsafe due to its write-hole problem, but also has
tons of hardcoded PAGE_SIZE.

So disable it for subpage support for now.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/disk-io.c | 10 ++++++++++
 fs/btrfs/volumes.c |  8 ++++++++
 2 files changed, 18 insertions(+)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 8c3db9076988..2dd48f4bec8f 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3406,6 +3406,16 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 			goto fail_alloc;
 		}
 	}
+	if (sectorsize != PAGE_SIZE) {
+		if (btrfs_super_incompat_flags(fs_info->super_copy) &
+			BTRFS_FEATURE_INCOMPAT_RAID56) {
+			btrfs_err(fs_info,
+	"raid5/6 is not yet supported for sector size %u with page size %lu",
+				sectorsize, PAGE_SIZE);
+			err = -EINVAL;
+			goto fail_alloc;
+		}
+	}
 
 	ret = btrfs_init_workqueues(fs_info, fs_devices);
 	if (ret) {
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 582695cee9d1..1e0829f342f8 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3937,11 +3937,19 @@ static inline int validate_convert_profile(struct btrfs_fs_info *fs_info,
 	if (!(bargs->flags & BTRFS_BALANCE_ARGS_CONVERT))
 		return true;
 
+	if (fs_info->sectorsize < PAGE_SIZE &&
+		bargs->target & BTRFS_BLOCK_GROUP_RAID56_MASK) {
+		btrfs_err(fs_info,
+	"RAID5/6 is not supported yet for sectorsize %u with page size %lu",
+			  fs_info->sectorsize, PAGE_SIZE);
+		goto invalid;
+	}
 	/* Profile is valid and does not have bits outside of the allowed set */
 	if (alloc_profile_is_valid(bargs->target, 1) &&
 	    (bargs->target & ~allowed) == 0)
 		return true;
 
+invalid:
 	btrfs_err(fs_info, "balance: invalid convert %s profile %s",
 			type, btrfs_bg_type_to_raid_name(bargs->target));
 	return false;
-- 
2.31.1