2020-05-15 04:43:46

by Ira Weiny

[permalink] [raw]
Subject: [PATCH v2 2/9] fs/ext4: Disallow verity if inode is DAX

From: Ira Weiny <[email protected]>

Verity and DAX are incompatible. Changing the DAX mode due to a verity
flag change is wrong without a corresponding address_space_operations
update.

Make the 2 options mutually exclusive by returning an error if DAX was
set first.

(Setting DAX is already disabled if Verity is set first.)

Reviewed-by: Jan Kara <[email protected]>
Signed-off-by: Ira Weiny <[email protected]>

---
Changes:
remove WARN_ON_ONCE
Add documentation for DAX/Verity exclusivity
---
Documentation/filesystems/ext4/verity.rst | 7 +++++++
fs/ext4/verity.c | 3 +++
2 files changed, 10 insertions(+)

diff --git a/Documentation/filesystems/ext4/verity.rst b/Documentation/filesystems/ext4/verity.rst
index 3e4c0ee0e068..51ab1aa17e59 100644
--- a/Documentation/filesystems/ext4/verity.rst
+++ b/Documentation/filesystems/ext4/verity.rst
@@ -39,3 +39,10 @@ is encrypted as well as the data itself.

Verity files cannot have blocks allocated past the end of the verity
metadata.
+
+Verity and DAX
+--------------
+
+Verity and DAX are not compatible and attempts to set both of these flags on a
+file will fail.
+
diff --git a/fs/ext4/verity.c b/fs/ext4/verity.c
index dc5ec724d889..f05a09fb2ae4 100644
--- a/fs/ext4/verity.c
+++ b/fs/ext4/verity.c
@@ -113,6 +113,9 @@ static int ext4_begin_enable_verity(struct file *filp)
handle_t *handle;
int err;

+ if (IS_DAX(inode))
+ return -EINVAL;
+
if (ext4_verity_in_progress(inode))
return -EBUSY;

--
2.25.1