ext4: don't enable DAX on new encrypted files

Currently, when a new encrypted regular file is created, the call to
ext4_set_inode_flags(inode, init=true) in __ext4_new_inode() is made
before EXT4_INODE_ENCRYPT is set.  As a result, it can set S_DAX if the
filesystem is mounted with "-o dax=always".

EXT4_INODE_ENCRYPT then actually gets set a bit later in
__ext4_new_inode(), when it calls fscrypt_set_context() which calls
ext4_set_context().  ext4_set_context() sets EXT4_INODE_ENCRYPT and
calls ext4_set_inode_flags(inode, init=false) to set S_ENCRYPTED too.

This was intended to clear S_DAX as well.  However, this was broken by
commit 043546e46dc7 ("fs/ext4: Only change S_DAX on inode load").  This
causes data written to the file to bypass encryption, also causing
xfstests failures such as generic/548 (when "-o dax=always" is used).

Fix this by simplifying the flow by making __ext4_new_inode() set
EXT4_INODE_ENCRYPT earlier.  This makes it take effect in
ext4_set_inode_flags(inode, init=true), making S_DAX never be set.

Similarly, make EXT4_STATE_MAY_INLINE_DATA never be set in the first
place on new encrypted inodes.  Then it doesn't need to be cleared.

As a result of these simplifications, ext4_set_context() no longer needs
to change inode flags or state when 'handle != NULL'.  Remove that too.

Reported-by: Disha Goel <disgoel@linux.ibm.com>
Reported-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Closes: https://lore.kernel.org/r/20260723085648.1500357-1-ojaswin@linux.ibm.com
Fixes: 043546e46dc7 ("fs/ext4: Only change S_DAX on inode load")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Tested-by: Disha Goel <disgoel@linux.ibm.com>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260730175212.36923-1-ebiggers@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

0 files changed, 0 insertions, 0 deletions