eCryptfs: remove header_extent_size

There is no point to keeping a separate header_extent_size and an extent_size.
 The total size of the header can always be represented as some multiple of
the regular data extent size.

[randy.dunlap@oracle.com: ecryptfs: fix printk format warning]
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 52 insertions, 36 deletions

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index 8e9b36df7881..9127b809044d 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -366,8 +366,8 @@ ecryptfs_extent_to_lwr_pg_idx_and_offset(unsigned long *lower_page_idx,
         int extents_per_page;
 
         bytes_occupied_by_headers_at_front =
-                ( crypt_stat->header_extent_size
-                  * crypt_stat->num_header_extents_at_front );
+                (crypt_stat->extent_size
+                 * crypt_stat->num_header_extents_at_front);
         extents_occupied_by_headers_at_front =
                 ( bytes_occupied_by_headers_at_front
                   / crypt_stat->extent_size );
@@ -376,8 +376,8 @@ ecryptfs_extent_to_lwr_pg_idx_and_offset(unsigned long *lower_page_idx,
         (*lower_page_idx) = lower_extent_num / extents_per_page;
         extent_offset = lower_extent_num % extents_per_page;
         (*byte_offset) = extent_offset * crypt_stat->extent_size;
-        ecryptfs_printk(KERN_DEBUG, " * crypt_stat->header_extent_size = "
-                        "[%d]\n", crypt_stat->header_extent_size);
+        ecryptfs_printk(KERN_DEBUG, " * crypt_stat->extent_size = "
+                        "[%d]\n", crypt_stat->extent_size);
         ecryptfs_printk(KERN_DEBUG, " * crypt_stat->"
                         "num_header_extents_at_front = [%d]\n",
                         crypt_stat->num_header_extents_at_front);
@@ -899,15 +899,17 @@ void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
         crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
         set_extent_mask_and_shift(crypt_stat);
         crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
-        if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) {
-                crypt_stat->header_extent_size =
-                        ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
-        } else
-                crypt_stat->header_extent_size = PAGE_CACHE_SIZE;
         if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
                 crypt_stat->num_header_extents_at_front = 0;
-        else
-                crypt_stat->num_header_extents_at_front = 1;
+        else {
+                if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
+                        crypt_stat->num_header_extents_at_front =
+                                (ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
+                                 / crypt_stat->extent_size);
+                else
+                        crypt_stat->num_header_extents_at_front =
+                                (PAGE_CACHE_SIZE / crypt_stat->extent_size);
+        }
 }
 
 /**
@@ -1319,7 +1321,7 @@ ecryptfs_write_header_metadata(char *virt,
         u32 header_extent_size;
         u16 num_header_extents_at_front;
 
-        header_extent_size = (u32)crypt_stat->header_extent_size;
+        header_extent_size = (u32)crypt_stat->extent_size;
         num_header_extents_at_front =
                 (u16)crypt_stat->num_header_extents_at_front;
         header_extent_size = cpu_to_be32(header_extent_size);
@@ -1415,7 +1417,7 @@ ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
                 set_fs(oldfs);
                 goto out;
         }
-        header_pages = ((crypt_stat->header_extent_size
+        header_pages = ((crypt_stat->extent_size
                          * crypt_stat->num_header_extents_at_front)
                         / PAGE_CACHE_SIZE);
         memset(page_virt, 0, PAGE_CACHE_SIZE);
@@ -1532,17 +1534,16 @@ static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
         virt += 4;
         memcpy(&num_header_extents_at_front, virt, 2);
         num_header_extents_at_front = be16_to_cpu(num_header_extents_at_front);
-        crypt_stat->header_extent_size = (int)header_extent_size;
         crypt_stat->num_header_extents_at_front =
                 (int)num_header_extents_at_front;
-        (*bytes_read) = 6;
+        (*bytes_read) = (sizeof(u32) + sizeof(u16));
         if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
-            && ((crypt_stat->header_extent_size
+            && ((crypt_stat->extent_size
                  * crypt_stat->num_header_extents_at_front)
                 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
                 rc = -EINVAL;
-                ecryptfs_printk(KERN_WARNING, "Invalid header extent size: "
-                                "[%d]\n", crypt_stat->header_extent_size);
+                printk(KERN_WARNING "Invalid number of header extents: [%zd]\n",
+                       crypt_stat->num_header_extents_at_front);
         }
         return rc;
 }
@@ -1557,8 +1558,7 @@ static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
  */
 static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
 {
-        crypt_stat->header_extent_size = 4096;
-        crypt_stat->num_header_extents_at_front = 1;
+        crypt_stat->num_header_extents_at_front = 2;
 }
 
 /**
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 78761e4bdab8..a618ab77642d 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -38,7 +38,7 @@
 /* Version verification for shared data structures w/ userspace */
 #define ECRYPTFS_VERSION_MAJOR 0x00
 #define ECRYPTFS_VERSION_MINOR 0x04
-#define ECRYPTFS_SUPPORTED_FILE_VERSION 0x02
+#define ECRYPTFS_SUPPORTED_FILE_VERSION 0x03
 /* These flags indicate which features are supported by the kernel
  * module; userspace tools such as the mount helper read
  * ECRYPTFS_VERSIONING_MASK from a sysfs handle in order to determine
@@ -67,8 +67,7 @@
 #define ECRYPTFS_MAX_KEY_BYTES 64
 #define ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES 512
 #define ECRYPTFS_DEFAULT_IV_BYTES 16
-#define ECRYPTFS_FILE_VERSION 0x02
-#define ECRYPTFS_DEFAULT_HEADER_EXTENT_SIZE 8192
+#define ECRYPTFS_FILE_VERSION 0x03
 #define ECRYPTFS_DEFAULT_EXTENT_SIZE 4096
 #define ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE 8192
 #define ECRYPTFS_DEFAULT_MSG_CTX_ELEMS 32
@@ -201,7 +200,7 @@ ecryptfs_get_key_payload_data(struct key *key)
 #define ECRYPTFS_SALT_BYTES 2
 #define MAGIC_ECRYPTFS_MARKER 0x3c81b7f5
 #define MAGIC_ECRYPTFS_MARKER_SIZE_BYTES 8      /* 4*2 */
-#define ECRYPTFS_FILE_SIZE_BYTES 8
+#define ECRYPTFS_FILE_SIZE_BYTES (sizeof(u64))
 #define ECRYPTFS_DEFAULT_CIPHER "aes"
 #define ECRYPTFS_DEFAULT_KEY_BYTES 16
 #define ECRYPTFS_DEFAULT_HASH "md5"
@@ -238,7 +237,6 @@ struct ecryptfs_crypt_stat {
         u32 flags;
         unsigned int file_version;
         size_t iv_bytes;
-        size_t header_extent_size;
         size_t num_header_extents_at_front;
         size_t extent_size; /* Data extent size; default is 4096 */
         size_t key_size;
@@ -273,6 +271,17 @@ struct ecryptfs_dentry_info {
 };
 
 /**
+ * ecryptfs_global_auth_tok - A key used to encrypt all new files under the mountpoint
+ * @flags: Status flags
+ * @mount_crypt_stat_list: These auth_toks hang off the mount-wide
+ *                         cryptographic context. Every time a new
+ *                         inode comes into existence, eCryptfs copies
+ *                         the auth_toks on that list to the set of
+ *                         auth_toks on the inode's crypt_stat
+ * @global_auth_tok_key: The key from the user's keyring for the sig
+ * @global_auth_tok: The key contents
+ * @sig: The key identifier
+ *
  * ecryptfs_global_auth_tok structs refer to authentication token keys
  * in the user keyring that apply to newly created files. A list of
  * these objects hangs off of the mount_crypt_stat struct for any
@@ -283,15 +292,21 @@ struct ecryptfs_dentry_info {
 struct ecryptfs_global_auth_tok {
 #define ECRYPTFS_AUTH_TOK_INVALID 0x00000001
         u32 flags;
-        struct list_head mount_crypt_stat_list; /* Default auth_tok list for
-                                                 * the mount_crypt_stat */
-        struct key *global_auth_tok_key; /* The key from the user's keyring for
-                                          * the sig */
-        struct ecryptfs_auth_tok *global_auth_tok; /* The key contents */
-        unsigned char sig[ECRYPTFS_SIG_SIZE_HEX + 1]; /* The key identifier */
+        struct list_head mount_crypt_stat_list;
+        struct key *global_auth_tok_key;
+        struct ecryptfs_auth_tok *global_auth_tok;
+        unsigned char sig[ECRYPTFS_SIG_SIZE_HEX + 1];
 };
 
 /**
+ * ecryptfs_key_tfm - Persistent key tfm
+ * @key_tfm: crypto API handle to the key
+ * @key_size: Key size in bytes
+ * @key_tfm_mutex: Mutex to ensure only one operation in eCryptfs is
+ *                 using the persistent TFM at any point in time
+ * @key_tfm_list: Handle to hang this off the module-wide TFM list
+ * @cipher_name: String name for the cipher for this TFM
+ *
  * Typically, eCryptfs will use the same ciphers repeatedly throughout
  * the course of its operations. In order to avoid unnecessarily
  * destroying and initializing the same cipher repeatedly, eCryptfs
@@ -301,7 +316,7 @@ struct ecryptfs_key_tfm {
         struct crypto_blkcipher *key_tfm;
         size_t key_size;
         struct mutex key_tfm_mutex;
-        struct list_head key_tfm_list; /* The module's tfm list */
+        struct list_head key_tfm_list;
         unsigned char cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
 };
 
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 131954b3fb98..abac91c58bfb 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -392,7 +392,8 @@ static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
                 dentry->d_sb)->mount_crypt_stat;
         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
-                        file_size = (crypt_stat->header_extent_size
+                        file_size = ((crypt_stat->extent_size
+                                      * crypt_stat->num_header_extents_at_front)
                                      + i_size_read(lower_dentry->d_inode));
                 else
                         file_size = i_size_read(lower_dentry->d_inode);
@@ -722,8 +723,8 @@ upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 {
         loff_t lower_size;
 
-        lower_size = ( crypt_stat->header_extent_size
-                       * crypt_stat->num_header_extents_at_front );
+        lower_size = (crypt_stat->extent_size
+                      * crypt_stat->num_header_extents_at_front);
         if (upper_size != 0) {
                 loff_t num_extents;
 
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index aaea55a61ea1..89dbbbbcce07 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -301,7 +301,7 @@ static int ecryptfs_readpage(struct file *file, struct page *page)
         } else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {
                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
                         int num_pages_in_header_region =
-                                (crypt_stat->header_extent_size
+                                (crypt_stat->extent_size
                                  / PAGE_CACHE_SIZE);
 
                         if (page->index < num_pages_in_header_region) {