[PATCH 01/19] btrfs: require at least 4 devices for RAID 6
Christoph Hellwig <[email protected]>
| Newsgroups | gmane.linux.ports.riscv,gmane.linux.kernel,gmane.linux.ports.arm.kernel,gmane.linux.ports.ppc64.devel,gmane.linux.kernel.cryptoapi,gmane.comp.file-systems.btrfs,gmane.linux.kernel.cross-arch,gmane.linux.raid |
|---|---|
| Message-ID | <[email protected]> |
While the RAID6 algorithm could in theory support 3 devices by just
copying the data disk to the two parity disks, this version is not only
useless because it is a suboptimal version of 3-way mirroring, but also
broken with various crashes and incorrect parity generation in various
architecture-optimized implementations. Disallow it similar to mdraid
which requires at least 4 devices for RAID 6.
Fixes: 53b381b3abeb ("Btrfs: RAID5 and RAID6")
Signed-off-by: Christoph Hellwig <[email protected]>
---
fs/btrfs/volumes.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index a88e68f90564..0b54b97bdad8 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -159,7 +159,7 @@ const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
.sub_stripes = 1,
.dev_stripes = 1,
.devs_max = 0,
- .devs_min = 3,
+ .devs_min = 4,
.tolerated_failures = 2,
.devs_increment = 1,
.ncopies = 1,
--
2.53.0