ext4 crypto: simplify and speed up filename encryption

Avoid using SHA-1 when calculating the user-visible filename when the
encryption key is available, and avoid decrypting lots of filenames
when searching for a directory entry in a directory block.

Change-Id: If4655f144784978ba0305b597bfa1c8d7bb69e63
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

1 files changed, 6 insertions, 3 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 0179654faf79..dfb113816672 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2093,9 +2093,11 @@ u32 ext4_fname_crypto_round_up(u32 size, u32 blksize);
 int ext4_fname_crypto_alloc_buffer(struct ext4_fname_crypto_ctx *ctx,
                                    u32 ilen, struct ext4_str *crypto_str);
 int _ext4_fname_disk_to_usr(struct ext4_fname_crypto_ctx *ctx,
+                            struct dx_hash_info *hinfo,
                             const struct ext4_str *iname,
                             struct ext4_str *oname);
 int ext4_fname_disk_to_usr(struct ext4_fname_crypto_ctx *ctx,
+                           struct dx_hash_info *hinfo,
                            const struct ext4_dir_entry_2 *de,
                            struct ext4_str *oname);
 int ext4_fname_usr_to_disk(struct ext4_fname_crypto_ctx *ctx,
@@ -2104,11 +2106,12 @@ int ext4_fname_usr_to_disk(struct ext4_fname_crypto_ctx *ctx,
 int ext4_fname_usr_to_hash(struct ext4_fname_crypto_ctx *ctx,
                            const struct qstr *iname,
                            struct dx_hash_info *hinfo);
-int ext4_fname_disk_to_hash(struct ext4_fname_crypto_ctx *ctx,
-                            const struct ext4_dir_entry_2 *de,
-                            struct dx_hash_info *hinfo);
 int ext4_fname_crypto_namelen_on_disk(struct ext4_fname_crypto_ctx *ctx,
                                       u32 namelen);
+int ext4_fname_match(struct ext4_fname_crypto_ctx *ctx, struct ext4_str *cstr,
+                     int len, const char * const name,
+                     struct ext4_dir_entry_2 *de);
+
 
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
 void ext4_put_fname_crypto_ctx(struct ext4_fname_crypto_ctx **ctx);