While the pblk argument to fscrypt_zeroout_range is declared as a
sector_t, it actually is interpreted as a logical block size unit, which
is highly unusual.  Switch to passing the 512 byte units that sector_t is
defined for.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20260302141922.370070-14-hch@lst.de
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

Range lengths are usually expressed as bytes in the VFS, switch
fscrypt_zeroout_range to this convention.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20260302141922.370070-13-hch@lst.de
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

Logical offsets into an inode are usually expressed as bytes in the VFS.
Switch fscrypt_zeroout_range to that convention.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20260302141922.370070-12-hch@lst.de
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

Logical offsets into an inode are usually expressed as bytes in the VFS.
Switch fscrypt_set_bio_crypt_ctx to that convention.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20260302141922.370070-9-hch@lst.de
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

Logical offsets into an inode are usually expressed as bytes in the VFS.
Switch fscrypt_mergeable_bio to that convention.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20260302141922.370070-8-hch@lst.de
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

fscrypt_set_bio_crypt_ctx_bh is only used by submit_bh_wbc now.  Move it
there and merge bh_get_inode_and_lblk_num into it.

Note that this does not add ifdefs for fscrypt as the compiler will
optimize away the dead code if it is not built in.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20260302141922.370070-6-hch@lst.de
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

ext4 already has the inode and folio and can't have a NULL
folio->mapping in this path. Open code fscrypt_mergeable_bio_bh in
io_submit_need_new_bio based on these simplifying assumptions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20260302141922.370070-5-hch@lst.de
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

Now that all fscrypt-capable filesystems store the pointer to
fscrypt_inode_info in the filesystem-specific part of the inode
structure, inode::i_crypt_info is no longer needed.  Update
fscrypt_inode_info_addr() to no longer support the fallback to
inode::i_crypt_info.  Finally, remove inode::i_crypt_info itself along
with the now-unnecessary forward declaration of fscrypt_inode_info.

The end result of the migration to the filesystem-specific pointer is
memory savings on CONFIG_FS_ENCRYPTION=y kernels for all filesystems
that don't support fscrypt.  Specifically, their in-memory inodes are
now smaller by the size of a pointer: either 4 or 8 bytes.

Co-developed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Link: https://lore.kernel.org/20250810075706.172910-8-ebiggers@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

Add an inode_info_offs field to struct fscrypt_operations, and update
fs/crypto/ to support it.  When set to a nonzero value, it specifies the
offset to the fscrypt_inode_info pointer within the filesystem-specific
part of the inode structure, to be used instead of inode::i_crypt_info.

Since this makes inode::i_crypt_info no longer necessarily used, update
comments that mentioned it.

This is a prerequisite for a later commit that removes
inode::i_crypt_info, saving memory and improving cache efficiency with
filesystems that don't support fscrypt.

Co-developed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Link: https://lore.kernel.org/20250810075706.172910-3-ebiggers@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

Add and use a helper function fscrypt_get_inode_info_raw().  It loads an
inode's fscrypt info pointer using a raw dereference, which is
appropriate when the caller knows the key setup already happened.

This eliminates most occurrences of inode::i_crypt_info in the source,
in preparation for replacing that with a filesystem-specific field.

Co-developed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Link: https://lore.kernel.org/20250810075706.172910-2-ebiggers@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>