[PATCH v6 06/28] btrfs: disallow NODATACOW in HMZONED mode

Naohiro Aota
2019-12-13T04:10:52Z

NODATACOW implies overwriting the file data on a device, which is
impossible in sequential required zones. Disable NODATACOW globally with
mount option and per-file NODATACOW attribute by masking FS_NOCOW_FL.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
fs/btrfs/hmzoned.c | 6 ++++++
fs/btrfs/ioctl.c | 3 +++
2 files changed, 9 insertions(+)

diff --git a/fs/btrfs/hmzoned.c b/fs/btrfs/hmzoned.c
index d62f11652973..21b8737dd289 100644
--- a/fs/btrfs/hmzoned.c
+++ b/fs/btrfs/hmzoned.c
@@ -266,5 +266,11 @@ int btrfs_check_mountopts_hmzoned(struct btrfs_fs_info *info)
return -EOPNOTSUPP;
}

+ if (btrfs_test_opt(info, NODATACOW)) {
+ btrfs_err(info,
+ "cannot enable nodatacow with HMZONED mode");
+ return -EOPNOTSUPP;
+ }
+
return 0;
}
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index a1ee0b775e65..a67421eb8bd5 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -94,6 +94,9 @@ static int btrfs_clone(struct inode *src, struct inode *inode,
static unsigned int btrfs_mask_fsflags_for_type(struct inode *inode,
unsigned int flags)
{
+ if (btrfs_fs_incompat(btrfs_sb(inode->i_sb), HMZONED))
+ flags &= ~FS_NOCOW_FL;
+
if (S_ISDIR(inode->i_mode))
return flags;
else if (S_ISREG(inode->i_mode))
--
2.24.0