Kernel/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-12-29 17:25:38 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

fscrypt: replace get_ino_and_lblk_bits with just has_32bit_inodes

Browse Source 
Now that fs/crypto/ computes the filesystem's lblk_bits from its maximum
file size, it is no longer necessary for filesystems to provide
lblk_bits via fscrypt_operations::get_ino_and_lblk_bits.

It is still necessary for fs/crypto/ to retrieve ino_bits from the
filesystem.  However, this is used only to decide whether inode numbers
fit in 32 bits.  Also, ino_bits is static for all relevant filesystems,
i.e. it doesn't depend on the filesystem instance.

Therefore, in the interest of keeping things as simple as possible,
replace 'get_ino_and_lblk_bits' with a flag 'has_32bit_inodes'.  This
can always be changed back to a function if a filesystem needs it to be
dynamic, but for now a static flag is all that's needed.

Link: https://lore.kernel.org/r/20230925055451.59499-5-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
This commit is contained in:
Eric Biggers 2023-09-24 22:54:50 -07:00
parent f0904e8bc3
commit 7a0263dc90
4 changed files with 28 additions and 49 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
fs/crypto/policy.c
View File

@ -118,11 +118,11 @@ static bool supported_direct_key_modes(const struct inode *inode,
}
static bool supported_iv_ino_lblk_policy(const struct fscrypt_policy_v2 *policy,
const struct inode *inode,
const char *type, int max_ino_bits)
const struct inode *inode)
{
const char *type = (policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64)
? "IV_INO_LBLK_64" : "IV_INO_LBLK_32";
struct super_block *sb = inode->i_sb;
int ino_bits = 64, lblk_bits = 64;
/*
* IV_INO_LBLK_* exist only because of hardware limitations, and
@ -149,9 +149,15 @@ static bool supported_iv_ino_lblk_policy(const struct fscrypt_policy_v2 *policy,
type, sb->s_id);
return false;
}
if (sb->s_cop->get_ino_and_lblk_bits)
sb->s_cop->get_ino_and_lblk_bits(sb, &ino_bits, &lblk_bits);
if (ino_bits > max_ino_bits) {
/*
* IV_INO_LBLK_64 and IV_INO_LBLK_32 both require that inode numbers fit
* in 32 bits. In principle, IV_INO_LBLK_32 could support longer inode
* numbers because it hashes the inode number; however, currently the
* inode number is gotten from inode::i_ino which is 'unsigned long'.
* So for now the implementation limit is 32 bits.
*/
if (!sb->s_cop->has_32bit_inodes) {
fscrypt_warn(inode,
"Can't use %s policy on filesystem '%s' because its inode numbers are too long",
type, sb->s_id);
@ -242,18 +248,9 @@ static bool fscrypt_supported_v2_policy(const struct fscrypt_policy_v2 *policy,
policy->filenames_encryption_mode))
return false;
if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) &&
!supported_iv_ino_lblk_policy(policy, inode, "IV_INO_LBLK_64", 32))
return false;
/*
* IV_INO_LBLK_32 hashes the inode number, so in principle it can
* support any ino_bits. However, currently the inode number is gotten
* from inode::i_ino which is 'unsigned long'. So for now the
* implementation limit is 32 bits.
*/
if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) &&
!supported_iv_ino_lblk_policy(policy, inode, "IV_INO_LBLK_32", 32))
if ((policy->flags & (FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 |
FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) &&
!supported_iv_ino_lblk_policy(policy, inode))
return false;
if (memchr_inv(policy->__reserved, 0, sizeof(policy->__reserved))) {

9
fs/ext4/crypto.c
View File

@ -232,20 +232,13 @@ static bool ext4_has_stable_inodes(struct super_block *sb)
return ext4_has_feature_stable_inodes(sb);
}
static void ext4_get_ino_and_lblk_bits(struct super_block *sb,
int *ino_bits_ret, int *lblk_bits_ret)
{
*ino_bits_ret = 8 * sizeof(EXT4_SB(sb)->s_es->s_inodes_count);
*lblk_bits_ret = 8 * sizeof(ext4_lblk_t);
}
const struct fscrypt_operations ext4_cryptops = {
.needs_bounce_pages = 1,
.has_32bit_inodes = 1,
.legacy_key_prefix = "ext4:",
.get_context = ext4_get_context,
.set_context = ext4_set_context,
.get_dummy_policy = ext4_get_dummy_policy,
.empty_dir = ext4_empty_dir,
.has_stable_inodes = ext4_has_stable_inodes,
.get_ino_and_lblk_bits = ext4_get_ino_and_lblk_bits,
};

9
fs/f2fs/super.c
View File

@ -3203,13 +3203,6 @@ static bool f2fs_has_stable_inodes(struct super_block *sb)
return true;
}
static void f2fs_get_ino_and_lblk_bits(struct super_block *sb,
int *ino_bits_ret, int *lblk_bits_ret)
{
*ino_bits_ret = 8 * sizeof(nid_t);
*lblk_bits_ret = 8 * sizeof(block_t);
}
static struct block_device **f2fs_get_devices(struct super_block *sb,
unsigned int *num_devs)
{
@ -3232,13 +3225,13 @@ static struct block_device **f2fs_get_devices(struct super_block *sb,
static const struct fscrypt_operations f2fs_cryptops = {
.needs_bounce_pages = 1,
.has_32bit_inodes = 1,
.legacy_key_prefix = "f2fs:",
.get_context = f2fs_get_context,
.set_context = f2fs_set_context,
.get_dummy_policy = f2fs_get_dummy_policy,
.empty_dir = f2fs_empty_dir,
.has_stable_inodes = f2fs_has_stable_inodes,
.get_ino_and_lblk_bits = f2fs_get_ino_and_lblk_bits,
.get_devices = f2fs_get_devices,
};
#endif

26
include/linux/fscrypt.h
View File

@ -74,6 +74,17 @@ struct fscrypt_operations {
*/
unsigned int needs_bounce_pages : 1;
/*
* If set, then fs/crypto/ will allow the use of encryption settings
* that assume inode numbers fit in 32 bits (i.e.
* FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64}), provided that the other
* prerequisites for these settings are also met. This is only useful
* if the filesystem wants to support inline encryption hardware that is
* limited to 32-bit or 64-bit data unit numbers and where programming
* keyslots is very slow.
*/
unsigned int has_32bit_inodes : 1;
/*
* This field exists only for backwards compatibility reasons and should
* only be set by the filesystems that are setting it already. It
@ -151,21 +162,6 @@ struct fscrypt_operations {
*/
bool (*has_stable_inodes)(struct super_block *sb);
/*
* Get the number of bits that the filesystem uses to represent inode
* numbers and file logical block numbers.
*
* By default, both of these are assumed to be 64-bit. This function
* can be implemented to declare that either or both of these numbers is
* shorter, which may allow the use of the
* FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64} flags and/or the use of
* inline crypto hardware whose maximum DUN length is less than 64 bits
* (e.g., eMMC v5.2 spec compliant hardware). This function only needs
* to be implemented if support for one of these features is needed.
*/
void (*get_ino_and_lblk_bits)(struct super_block *sb,
int *ino_bits_ret, int *lblk_bits_ret);
/*
* Return an array of pointers to the block devices to which the
* filesystem may write encrypted file contents, NULL if the filesystem