This patchset moves the "post read processing" code into a file of its own (i.e. fs/post_read_process.c) and modifies the generic do_mpage_readpge() to make use of the functionality provided. "Post read processing" implements code to track the state machine that needs to be executed after reading data from files that are encrypted and/or have verity metadata associated with them. With these changes in place, the patchset changes Ext4 to use mpage_readpage[s] instead of its own custom ext4_readpage[s]() functions. This is done to reduce duplicity of code across filesystems. Also, Post read processing source files will be built only if one of CONFIG_FS_ENCRYPTION and CONFIG_FS_VERITY is enabled. Members of "struct fscrypt_ctx" that tracked status of a "write" operation are now made an anonymous structure since the decryption state tracking members are now moved into "struct post_read_ctx". The patchset also modifies fs/buffer.c and fscrypt functionality to get file encryption/decryption to work with subpage-sized blocks. The following fixes from Eric Biggers are prerequisites for this patchset, fscrypt: fix race where ->lookup() marks plaintext dentry as ciphertext fscrypt: only set dentry_operations on ciphertext dentries fscrypt: clear DCACHE_ENCRYPTED_NAME when unaliasing directory fscrypt: fix race allowing rename() and link() of ciphertext dentries fscrypt: clean up and improve dentry revalidation The patches can also be obtained from, "https://github.com/chandanr/linux.git subpage-encryption" TODO: 1. The subset of the fscrypt_encrypt_page() that deals with FS_CFLG_OWN_PAGES case still needs to be tested. UBIFS seems to be the only user of this piece of code. 2. Verity changes needs to be added for F2FS and I will add them in the next patchset based on the review comments obtained for the current patchset. Changelog: RFC V1 -> RFC V2: 1. Describe the purpose of "Post processing code" in the cover letter. 2. Fix build errors when CONFIG_FS_VERITY is enabled. Chandan Rajendra (14): ext4: Clear BH_Uptodate flag on decryption error Consolidate "post read processing" into a new file fsverity: Add call back to decide if verity check has to be performed fsverity: Add call back to determine readpage limit fs/mpage.c: Integrate post read processing ext4: Wire up ext4_readpage[s] to use mpage_readpage[s] Remove the term "bio" from post read processing Add decryption support for sub-pagesized blocks ext4: Decrypt all boundary blocks when doing buffered write ext4: Decrypt the block that needs to be partially zeroed fscrypt_encrypt_page: Loop across all blocks mapped by a page range ext4: Compute logical block and the page range to be encrypted fscrypt_zeroout_range: Encrypt all zeroed out blocks of a page ext4: Enable encryption for subpage-sized blocks Documentation/filesystems/fscrypt.rst | 4 +- fs/Makefile | 4 + fs/buffer.c | 85 +++-- fs/crypto/bio.c | 109 ++++--- fs/crypto/crypto.c | 73 +++-- fs/crypto/fscrypt_private.h | 3 + fs/ext4/Makefile | 2 +- fs/ext4/ext4.h | 2 - fs/ext4/inode.c | 47 ++- fs/ext4/page-io.c | 9 +- fs/ext4/readpage.c | 445 -------------------------- fs/ext4/super.c | 40 ++- fs/f2fs/data.c | 148 ++------- fs/f2fs/super.c | 9 +- fs/mpage.c | 51 ++- fs/post_read_process.c | 155 +++++++++ fs/verity/verify.c | 12 + include/linux/buffer_head.h | 1 + include/linux/fscrypt.h | 20 +- include/linux/fsverity.h | 2 + include/linux/post_read_process.h | 22 ++ 21 files changed, 511 insertions(+), 732 deletions(-) delete mode 100644 fs/ext4/readpage.c create mode 100644 fs/post_read_process.c create mode 100644 include/linux/post_read_process.h -- 2.19.1
