From: Ira Weiny <ira.weiny@xxxxxxxxx> Encryption and DAX are incompatible. Changing the DAX mode due to a change in Encryption mode is wrong without a corresponding address_space_operations update. Make the 2 options mutually exclusive by returning an error if DAX was set first. Furthermore, clarify the documentation of the exclusivity and how that will work. Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx> --- Changes: remove WARN_ON_ONCE Add documentation to the encrypt doc WRT DAX --- Documentation/filesystems/fscrypt.rst | 4 +++- fs/ext4/super.c | 10 +--------- 2 files changed, 4 insertions(+), 10 deletions(-) diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst index aa072112cfff..1475b8d52fef 100644 --- a/Documentation/filesystems/fscrypt.rst +++ b/Documentation/filesystems/fscrypt.rst @@ -1038,7 +1038,9 @@ astute users may notice some differences in behavior: - The ext4 filesystem does not support data journaling with encrypted regular files. It will fall back to ordered data mode instead. -- DAX (Direct Access) is not supported on encrypted files. +- DAX (Direct Access) is not supported on encrypted files. Attempts to enable + DAX on an encrypted file will fail. Mount options will _not_ enable DAX on + encrypted files. - The st_size of an encrypted symlink will not necessarily give the length of the symlink target as required by POSIX. It will actually diff --git a/fs/ext4/super.c b/fs/ext4/super.c index bf5fcb477f66..9873ab27e3fa 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1320,7 +1320,7 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len, if (inode->i_ino == EXT4_ROOT_INO) return -EPERM; - if (WARN_ON_ONCE(IS_DAX(inode) && i_size_read(inode))) + if (IS_DAX(inode)) return -EINVAL; res = ext4_convert_inline_data(inode); @@ -1344,10 +1344,6 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len, ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT); ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA); - /* - * Update inode->i_flags - S_ENCRYPTED will be enabled, - * S_DAX may be disabled - */ ext4_set_inode_flags(inode); } return res; @@ -1371,10 +1367,6 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len, ctx, len, 0); if (!res) { ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT); - /* - * Update inode->i_flags - S_ENCRYPTED will be enabled, - * S_DAX may be disabled - */ ext4_set_inode_flags(inode); res = ext4_mark_inode_dirty(handle, inode); if (res) -- 2.25.1