The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <[email protected]>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x da32af420d6d466e247c43ac0b829edeac7ae0ad
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026082429-reset-mocker-6122@gregkh' --subject-prefix 'PATCH 5.10.y' 'HEAD^..'
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From da32af420d6d466e247c43ac0b829edeac7ae0ad Mon Sep 17 00:00:00 2001
From: Eric Biggers <[email protected]>
Date: Thu, 30 Jul 2026 10:52:12 -0700
Subject: [PATCH] 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 <[email protected]>
Reported-by: Ojaswin Mujoo <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Fixes: 043546e46dc7 ("fs/ext4: Only change S_DAX on inode load")
Cc: [email protected]
Signed-off-by: Eric Biggers <[email protected]>
Tested-by: Disha Goel <[email protected]>
Reviewed-by: Ojaswin Mujoo <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
index f41f320f4437..3971986de028 100644
--- a/fs/ext4/crypto.c
+++ b/fs/ext4/crypto.c
@@ -144,7 +144,13 @@ 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)))
+ /*
+ * For new encrypted inodes, S_DAX is never set in the first place.
+ *
+ * For existing inodes, this is called only on empty directories. ext4
+ * never sets S_DAX on directories.
+ */
+ if (WARN_ON_ONCE(IS_DAX(inode)))
return -EINVAL;
if (ext4_test_inode_flag(inode, EXT4_INODE_DAX))
@@ -163,6 +169,14 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
*/
if (handle) {
+ /*
+ * __ext4_new_inode() should have already set the encrypt flag
+ * on the inode and avoided enabling inline data.
+ */
+ if (WARN_ON_ONCE(!IS_ENCRYPTED(inode)))
+ return -EINVAL;
+ if (WARN_ON_ONCE(ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)))
+ return -EINVAL;
/*
* Since the inode is new it is ok to pass the
* XATTR_CREATE flag. This is necessary to match the
@@ -170,21 +184,10 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
* function with the credits allocated for the new
* inode.
*/
- res = ext4_xattr_set_handle(handle, inode,
- EXT4_XATTR_INDEX_ENCRYPTION,
- EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
- ctx, len, XATTR_CREATE);
- if (!res) {
- 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, false);
- }
- return res;
+ return ext4_xattr_set_handle(handle, inode,
+ EXT4_XATTR_INDEX_ENCRYPTION,
+ EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
+ ctx, len, XATTR_CREATE);
}
res = dquot_initialize(inode);
@@ -205,10 +208,7 @@ 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
- */
+ /* Update inode->i_flags to set S_ENCRYPTED. */
ext4_set_inode_flags(inode, false);
res = ext4_mark_inode_dirty(handle, inode);
if (res)
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index a40cb27f8116..a5831fc536db 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -997,6 +997,8 @@ struct inode *__ext4_new_inode(struct mnt_idmap *idmap,
err = fscrypt_prepare_new_inode(dir, inode, &encrypt);
if (err)
goto out;
+ if (encrypt)
+ i_flags |= EXT4_ENCRYPT_FL;
}
err = dquot_initialize(inode);
@@ -1306,6 +1308,8 @@ struct inode *__ext4_new_inode(struct mnt_idmap *idmap,
ei->i_extra_isize = sbi->s_want_extra_isize;
ei->i_inline_off = 0;
if (ext4_has_feature_inline_data(sb) &&
+ /* Encrypted inodes cannot have inline data */
+ !(ei->i_flags & EXT4_ENCRYPT_FL) &&
(!(ei->i_flags & (EXT4_DAX_FL|EXT4_EA_INODE_FL)) || S_ISDIR(mode)))
ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
ret = inode;
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