On 30/07/26 11:22 pm, Eric Biggers wrote:
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]>
I have tested on a -o dax=always ext4 filesystem on ppc64le with the following xfstests configuration. All failing encryption tests in the
generic group now pass. MOUNT_OPTIONS="-o block_validity,dax" MKFS_OPTIONS="-b 65536" Feel free to add Tested-by: Disha Goel <[email protected]>
--- fs/ext4/crypto.c | 40 ++++++++++++++++++++-------------------- fs/ext4/ialloc.c | 4 ++++ 2 files changed, 24 insertions(+), 20 deletions(-) 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; base-commit: f5098b6bae761e346ebcd9da7f95622c04733cff
-- Regards, Disha
