[PATCH] eCryptfs: Generalize metadata read/write

Generalize the metadata reading and writing mechanisms, with two targets for
now: metadata in file header and metadata in the user.ecryptfs xattr of the
lower file.

[akpm@osdl.org: printk warning fix]
[bunk@stusta.de: make some needlessly global code static]
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

7 files changed, 348 insertions, 146 deletions

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index 6d85aabb0179..96fa40a48b4f 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -3,7 +3,7 @@
  *
  * Copyright (C) 1997-2004 Erez Zadok
  * Copyright (C) 2001-2004 Stony Brook University
- * Copyright (C) 2004-2006 International Business Machines Corp.
+ * Copyright (C) 2004-2007 International Business Machines Corp.
  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  *              Michael C. Thompson <mcthomps@us.ibm.com>
  *
@@ -863,7 +863,10 @@ void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
                         ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
         } else
                 crypt_stat->header_extent_size = PAGE_CACHE_SIZE;
-        crypt_stat->num_header_extents_at_front = 1;
+        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;
 }
 
 /**
@@ -1021,7 +1024,7 @@ int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
  *
  * Returns one if marker found; zero if not found
  */
-int contains_ecryptfs_marker(char *data)
+static int contains_ecryptfs_marker(char *data)
 {
         u32 m_1, m_2;
 
@@ -1047,7 +1050,8 @@ struct ecryptfs_flag_map_elem {
 /* Add support for additional flags by adding elements here. */
 static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
         {0x00000001, ECRYPTFS_ENABLE_HMAC},
-        {0x00000002, ECRYPTFS_ENCRYPTED}
+        {0x00000002, ECRYPTFS_ENCRYPTED},
+        {0x00000004, ECRYPTFS_METADATA_IN_XATTR}
 };
 
 /**
@@ -1207,8 +1211,8 @@ int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code)
  *
  * Returns zero on success; non-zero otherwise
  */
-int ecryptfs_read_header_region(char *data, struct dentry *dentry,
-                                struct vfsmount *mnt)
+static int ecryptfs_read_header_region(char *data, struct dentry *dentry,
+                                       struct vfsmount *mnt)
 {
         struct file *lower_file;
         mm_segment_t oldfs;
@@ -1237,6 +1241,21 @@ out:
         return rc;
 }
 
+int ecryptfs_read_and_validate_header_region(char *data, struct dentry *dentry,
+                                             struct vfsmount *mnt)
+{
+        int rc;
+
+        rc = ecryptfs_read_header_region(data, dentry, mnt);
+        if (rc)
+                goto out;
+        if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES))
+                rc = -EINVAL;
+out:
+        return rc;
+}
+
+
 static void
 write_header_metadata(char *virt, struct ecryptfs_crypt_stat *crypt_stat,
                       size_t *written)
@@ -1288,9 +1307,9 @@ struct kmem_cache *ecryptfs_header_cache_2;
  *
  * Returns zero on success
  */
-int ecryptfs_write_headers_virt(char *page_virt,
-                                struct ecryptfs_crypt_stat *crypt_stat,
-                                struct dentry *ecryptfs_dentry)
+static int ecryptfs_write_headers_virt(char *page_virt, size_t *size,
+                                       struct ecryptfs_crypt_stat *crypt_stat,
+                                       struct dentry *ecryptfs_dentry)
 {
         int rc;
         size_t written;
@@ -1309,11 +1328,53 @@ int ecryptfs_write_headers_virt(char *page_virt,
         if (rc)
                 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
                                 "set; rc = [%d]\n", rc);
+        if (size) {
+                offset += written;
+                *size = offset;
+        }
+        return rc;
+}
+
+static int ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
+                                               struct file *lower_file,
+                                               char *page_virt)
+{
+        mm_segment_t oldfs;
+        int current_header_page;
+        int header_pages;
+
+        lower_file->f_pos = 0;
+        oldfs = get_fs();
+        set_fs(get_ds());
+        lower_file->f_op->write(lower_file, (char __user *)page_virt,
+                                PAGE_CACHE_SIZE, &lower_file->f_pos);
+        header_pages = ((crypt_stat->header_extent_size
+                         * crypt_stat->num_header_extents_at_front)
+                        / PAGE_CACHE_SIZE);
+        memset(page_virt, 0, PAGE_CACHE_SIZE);
+        current_header_page = 1;
+        while (current_header_page < header_pages) {
+                lower_file->f_op->write(lower_file, (char __user *)page_virt,
+                                        PAGE_CACHE_SIZE, &lower_file->f_pos);
+                current_header_page++;
+        }
+        set_fs(oldfs);
+        return 0;
+}
+
+static int ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
+                                            struct ecryptfs_crypt_stat *crypt_stat,
+                                            char *page_virt, size_t size)
+{
+        int rc;
+
+        rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
+                               size, 0);
         return rc;
 }
 
 /**
- * ecryptfs_write_headers
+ * ecryptfs_write_metadata
  * @lower_file: The lower file struct, which was returned from dentry_open
  *
  * Write the file headers out.  This will likely involve a userspace
@@ -1324,14 +1385,12 @@ int ecryptfs_write_headers_virt(char *page_virt,
  *
  * Returns zero on success; non-zero on error
  */
-int ecryptfs_write_headers(struct dentry *ecryptfs_dentry,
-                           struct file *lower_file)
+int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
+                            struct file *lower_file)
 {
-        mm_segment_t oldfs;
         struct ecryptfs_crypt_stat *crypt_stat;
         char *page_virt;
-        int current_header_page;
-        int header_pages;
+        size_t size;
         int rc = 0;
 
         crypt_stat = &ecryptfs_inode_to_private(
@@ -1358,48 +1417,36 @@ int ecryptfs_write_headers(struct dentry *ecryptfs_dentry,
                 rc = -ENOMEM;
                 goto out;
         }
-
-        rc = ecryptfs_write_headers_virt(page_virt, crypt_stat,
-                                         ecryptfs_dentry);
+        rc = ecryptfs_write_headers_virt(page_virt, &size, crypt_stat,
+                                         ecryptfs_dentry);
         if (unlikely(rc)) {
                 ecryptfs_printk(KERN_ERR, "Error whilst writing headers\n");
                 memset(page_virt, 0, PAGE_CACHE_SIZE);
                 goto out_free;
         }
-        ecryptfs_printk(KERN_DEBUG,
-                        "Writing key packet set to underlying file\n");
-        lower_file->f_pos = 0;
-        oldfs = get_fs();
-        set_fs(get_ds());
-        ecryptfs_printk(KERN_DEBUG, "Calling lower_file->f_op->"
-                        "write() w/ header page; lower_file->f_pos = "
-                        "[0x%.16x]\n", lower_file->f_pos);
-        lower_file->f_op->write(lower_file, (char __user *)page_virt,
-                                PAGE_CACHE_SIZE, &lower_file->f_pos);
-        header_pages = ((crypt_stat->header_extent_size
-                         * crypt_stat->num_header_extents_at_front)
-                        / PAGE_CACHE_SIZE);
-        memset(page_virt, 0, PAGE_CACHE_SIZE);
-        current_header_page = 1;
-        while (current_header_page < header_pages) {
-                ecryptfs_printk(KERN_DEBUG, "Calling lower_file->f_op->"
-                                "write() w/ zero'd page; lower_file->f_pos = "
-                                "[0x%.16x]\n", lower_file->f_pos);
-                lower_file->f_op->write(lower_file, (char __user *)page_virt,
-                                        PAGE_CACHE_SIZE, &lower_file->f_pos);
-                current_header_page++;
+        if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
+                rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry,
+                                                      crypt_stat, page_virt,
+                                                      size);
+        else
+                rc = ecryptfs_write_metadata_to_contents(crypt_stat, lower_file,
+                                                         page_virt);
+        if (rc) {
+                printk(KERN_ERR "Error writing metadata out to lower file; "
+                       "rc = [%d]\n", rc);
+                goto out_free;
         }
-        set_fs(oldfs);
-        ecryptfs_printk(KERN_DEBUG,
-                        "Done writing key packet set to underlying file.\n");
 out_free:
         kmem_cache_free(ecryptfs_header_cache_0, page_virt);
 out:
         return rc;
 }
 
+#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
+#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
 static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
-                                 char *virt, int *bytes_read)
+                                 char *virt, int *bytes_read,
+                                 int validate_header_size)
 {
         int rc = 0;
         u32 header_extent_size;
@@ -1414,9 +1461,10 @@ static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
         crypt_stat->num_header_extents_at_front =
                 (int)num_header_extents_at_front;
         (*bytes_read) = 6;
-        if ((crypt_stat->header_extent_size
-             * crypt_stat->num_header_extents_at_front)
-            < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) {
+        if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
+            && ((crypt_stat->header_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);
@@ -1447,7 +1495,8 @@ static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
  */
 static int ecryptfs_read_headers_virt(char *page_virt,
                                       struct ecryptfs_crypt_stat *crypt_stat,
-                                      struct dentry *ecryptfs_dentry)
+                                      struct dentry *ecryptfs_dentry,
+                                      int validate_header_size)
 {
         int rc = 0;
         int offset;
@@ -1481,7 +1530,7 @@ static int ecryptfs_read_headers_virt(char *page_virt,
         offset += bytes_read;
         if (crypt_stat->file_version >= 1) {
                 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
-                                           &bytes_read);
+                                           &bytes_read, validate_header_size);
                 if (rc) {
                         ecryptfs_printk(KERN_WARNING, "Error reading header "
                                         "metadata; rc = [%d]\n", rc);
@@ -1496,12 +1545,60 @@ out:
 }
 
 /**
- * ecryptfs_read_headers
+ * ecryptfs_read_xattr_region
+ *
+ * Attempts to read the crypto metadata from the extended attribute
+ * region of the lower file.
+ */
+int ecryptfs_read_xattr_region(char *page_virt, struct dentry *ecryptfs_dentry)
+{
+        ssize_t size;
+        int rc = 0;
+
+        size = ecryptfs_getxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME,
+                                 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
+        if (size < 0) {
+                printk(KERN_DEBUG "Error attempting to read the [%s] "
+                       "xattr from the lower file; return value = [%zd]\n",
+                       ECRYPTFS_XATTR_NAME, size);
+                rc = -EINVAL;
+                goto out;
+        }
+out:
+        return rc;
+}
+
+int ecryptfs_read_and_validate_xattr_region(char *page_virt,
+                                            struct dentry *ecryptfs_dentry)
+{
+        int rc;
+
+        rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry);
+        if (rc)
+                goto out;
+        if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
+                printk(KERN_WARNING "Valid data found in [%s] xattr, but "
+                        "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
+                rc = -EINVAL;
+        }
+out:
+        return rc;
+}
+
+/**
+ * ecryptfs_read_metadata
+ *
+ * Common entry point for reading file metadata. From here, we could
+ * retrieve the header information from the header region of the file,
+ * the xattr region of the file, or some other repostory that is
+ * stored separately from the file itself. The current implementation
+ * supports retrieving the metadata information from the file contents
+ * and from the xattr region.
  *
  * Returns zero if valid headers found and parsed; non-zero otherwise
  */
-int ecryptfs_read_headers(struct dentry *ecryptfs_dentry,
-                          struct file *lower_file)
+int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry,
+                           struct file *lower_file)
 {
         int rc = 0;
         char *page_virt = NULL;
@@ -1530,11 +1627,36 @@ int ecryptfs_read_headers(struct dentry *ecryptfs_dentry,
                 goto out;
         }
         rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
-                                        ecryptfs_dentry);
+                                        ecryptfs_dentry,
+                                        ECRYPTFS_VALIDATE_HEADER_SIZE);
         if (rc) {
-                ecryptfs_printk(KERN_DEBUG, "Valid eCryptfs headers not "
-                                "found\n");
-                rc = -EINVAL;
+                rc = ecryptfs_read_xattr_region(page_virt,
+                                                ecryptfs_dentry);
+                if (rc) {
+                        printk(KERN_DEBUG "Valid eCryptfs headers not found in "
+                               "file header region or xattr region\n");
+                        rc = -EINVAL;
+                        goto out;
+                }
+                rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
+                                                ecryptfs_dentry,
+                                                ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
+                if (rc) {
+                        printk(KERN_DEBUG "Valid eCryptfs headers not found in "
+                               "file xattr region either\n");
+                        rc = -EINVAL;
+                }
+                if (crypt_stat->mount_crypt_stat->flags
+                    & ECRYPTFS_XATTR_METADATA_ENABLED) {
+                        crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
+                } else {
+                        printk(KERN_WARNING "Attempt to access file with "
+                               "crypto metadata only in the extended attribute "
+                               "region, but eCryptfs was mounted without "
+                               "xattr support enabled. eCryptfs will not treat "
+                               "this like an encrypted file.\n");
+                        rc = -EINVAL;
+                }
         }
 out:
         if (page_virt) {
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 7bbd6e6e2743..020abcd16f0e 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -4,7 +4,7 @@
  *
  * Copyright (C) 1997-2003 Erez Zadok
  * Copyright (C) 2001-2003 Stony Brook University
- * Copyright (C) 2004-2006 International Business Machines Corp.
+ * Copyright (C) 2004-2007 International Business Machines Corp.
  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  *              Trevor S. Highland <trevor.highland@gmail.com>
  *              Tyler Hicks <tyhicks@ou.edu>
@@ -50,8 +50,8 @@
 #define ECRYPTFS_VERSIONING_XATTR                 0x00000010
 #define ECRYPTFS_VERSIONING_MASK (ECRYPTFS_VERSIONING_PASSPHRASE \
                                   | ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH \
-                                  | ECRYPTFS_VERSIONING_PUBKEY)
-
+                                  | ECRYPTFS_VERSIONING_PUBKEY \
+                                  | ECRYPTFS_VERSIONING_XATTR)
 #define ECRYPTFS_MAX_PASSWORD_LENGTH 64
 #define ECRYPTFS_MAX_PASSPHRASE_BYTES ECRYPTFS_MAX_PASSWORD_LENGTH
 #define ECRYPTFS_SALT_SIZE 8
@@ -83,6 +83,7 @@
 #define ECRYPTFS_TRANSPORT_CONNECTOR 1
 #define ECRYPTFS_TRANSPORT_RELAYFS 2
 #define ECRYPTFS_DEFAULT_TRANSPORT ECRYPTFS_TRANSPORT_NETLINK
+#define ECRYPTFS_XATTR_NAME "user.ecryptfs"
 
 #define RFC2440_CIPHER_DES3_EDE 0x02
 #define RFC2440_CIPHER_CAST_5 0x03
@@ -327,18 +328,6 @@ struct ecryptfs_msg_ctx {
         struct mutex mux;
 };
 
-extern struct list_head ecryptfs_msg_ctx_free_list;
-extern struct list_head ecryptfs_msg_ctx_alloc_list;
-extern struct mutex ecryptfs_msg_ctx_lists_mux;
-
-#define ecryptfs_uid_hash(uid) \
-        hash_long((unsigned long)uid, ecryptfs_hash_buckets)
-extern struct hlist_head *ecryptfs_daemon_id_hash;
-extern struct mutex ecryptfs_daemon_id_hash_mux;
-extern int ecryptfs_hash_buckets;
-
-extern unsigned int ecryptfs_msg_counter;
-extern struct ecryptfs_msg_ctx *ecryptfs_msg_ctx_arr;
 extern unsigned int ecryptfs_transport;
 
 struct ecryptfs_daemon_id {
@@ -479,6 +468,7 @@ extern struct kmem_cache *ecryptfs_sb_info_cache;
 extern struct kmem_cache *ecryptfs_header_cache_0;
 extern struct kmem_cache *ecryptfs_header_cache_1;
 extern struct kmem_cache *ecryptfs_header_cache_2;
+extern struct kmem_cache *ecryptfs_xattr_cache;
 extern struct kmem_cache *ecryptfs_lower_page_cache;
 
 int ecryptfs_interpose(struct dentry *hidden_dentry,
@@ -505,9 +495,13 @@ int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat);
 int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
                                            char *cipher_name,
                                            char *chaining_modifier);
-int ecryptfs_write_inode_size_to_header(struct file *lower_file,
-                                        struct inode *lower_inode,
-                                        struct inode *inode);
+#define ECRYPTFS_LOWER_I_MUTEX_NOT_HELD 0
+#define ECRYPTFS_LOWER_I_MUTEX_HELD 1
+int ecryptfs_write_inode_size_to_metadata(struct file *lower_file,
+                                          struct inode *lower_inode,
+                                          struct inode *inode,
+                                          struct dentry *ecryptfs_dentry,
+                                          int lower_i_mutex_held);
 int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode,
                             struct file *lower_file,
                             unsigned long lower_page_index, int byte_offset,
@@ -529,17 +523,15 @@ int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
                                               struct writeback_control *wbc);
 int ecryptfs_encrypt_page(struct ecryptfs_page_crypt_context *ctx);
 int ecryptfs_decrypt_page(struct file *file, struct page *page);
-int ecryptfs_write_headers(struct dentry *ecryptfs_dentry,
+int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
+                            struct file *lower_file);
+int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry,
                            struct file *lower_file);
-int ecryptfs_write_headers_virt(char *page_virt,
-                                struct ecryptfs_crypt_stat *crypt_stat,
-                                struct dentry *ecryptfs_dentry);
-int ecryptfs_read_headers(struct dentry *ecryptfs_dentry,
-                          struct file *lower_file);
 int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry);
-int contains_ecryptfs_marker(char *data);
-int ecryptfs_read_header_region(char *data, struct dentry *dentry,
-                                struct vfsmount *mnt);
+int ecryptfs_read_and_validate_header_region(char *data, struct dentry *dentry,
+                                             struct vfsmount *mnt);
+int ecryptfs_read_and_validate_xattr_region(char *page_virt,
+                                            struct dentry *ecryptfs_dentry);
 u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat);
 int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code);
 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat);
@@ -562,6 +554,11 @@ int ecryptfs_open_lower_file(struct file **lower_file,
                              struct dentry *lower_dentry,
                              struct vfsmount *lower_mnt, int flags);
 int ecryptfs_close_lower_file(struct file *lower_file);
+ssize_t ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
+                          size_t size);
+int
+ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
+                  size_t size, int flags);
 
 int ecryptfs_process_helo(unsigned int transport, uid_t uid, pid_t pid);
 int ecryptfs_process_quit(uid_t uid, pid_t pid);
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 779c3477d93c..f22c3a73485c 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -3,7 +3,7 @@
  *
  * Copyright (C) 1997-2004 Erez Zadok
  * Copyright (C) 2001-2004 Stony Brook University
- * Copyright (C) 2004-2006 International Business Machines Corp.
+ * Copyright (C) 2004-2007 International Business Machines Corp.
  *   Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
  *              Michael C. Thompson <mcthomps@us.ibm.com>
  *
@@ -293,26 +293,11 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
                 goto out;
         }
         mutex_lock(&crypt_stat->cs_mutex);
-        if (i_size_read(lower_inode) < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) {
-                if (!(mount_crypt_stat->flags
-                      & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
-                        rc = -EIO;
-                        printk(KERN_WARNING "Attempt to read file that is "
-                               "not in a valid eCryptfs format, and plaintext "
-                               "passthrough mode is not enabled; returning "
-                               "-EIO\n");
-                        mutex_unlock(&crypt_stat->cs_mutex);
-                        goto out_puts;
-                }
-                crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
-                rc = 0;
-                mutex_unlock(&crypt_stat->cs_mutex);
-                goto out;
-        } else if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags,
-                                        ECRYPTFS_POLICY_APPLIED)
-                   || !ECRYPTFS_CHECK_FLAG(crypt_stat->flags,
-                                           ECRYPTFS_KEY_VALID)) {
-                rc = ecryptfs_read_headers(ecryptfs_dentry, lower_file);
+        if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags,
+                                 ECRYPTFS_POLICY_APPLIED)
+            || !ECRYPTFS_CHECK_FLAG(crypt_stat->flags,
+                                    ECRYPTFS_KEY_VALID)) {
+                rc = ecryptfs_read_metadata(ecryptfs_dentry, lower_file);
                 if (rc) {
                         ecryptfs_printk(KERN_DEBUG,
                                         "Valid headers not found\n");
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index d4f02f3e18d7..6b45b2908f17 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -3,7 +3,7 @@
  *
  * Copyright (C) 1997-2004 Erez Zadok
  * Copyright (C) 2001-2004 Stony Brook University
- * Copyright (C) 2004-2006 International Business Machines Corp.
+ * Copyright (C) 2004-2007 International Business Machines Corp.
  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  *              Michael C. Thompsion <mcthomps@us.ibm.com>
  *
@@ -169,7 +169,9 @@ static int grow_file(struct dentry *ecryptfs_dentry, struct file *lower_file,
                 goto out;
         }
         i_size_write(inode, 0);
-        ecryptfs_write_inode_size_to_header(lower_file, lower_inode, inode);
+        ecryptfs_write_inode_size_to_metadata(lower_file, lower_inode, inode,
+                                              ecryptfs_dentry,
+                                              ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
         ECRYPTFS_SET_FLAG(ecryptfs_inode_to_private(inode)->crypt_stat.flags,
                           ECRYPTFS_NEW_FILE);
 out:
@@ -225,7 +227,7 @@ static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
                                 "context\n");
                 goto out_fput;
         }
-        rc = ecryptfs_write_headers(ecryptfs_dentry, lower_file);
+        rc = ecryptfs_write_metadata(ecryptfs_dentry, lower_file);
         if (rc) {
                 ecryptfs_printk(KERN_DEBUG, "Error writing headers\n");
                 goto out_fput;
@@ -362,32 +364,33 @@ static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
         }
         /* Released in this function */
         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
-                                     GFP_USER);
+                                      GFP_USER);
         if (!page_virt) {
                 rc = -ENOMEM;
                 ecryptfs_printk(KERN_ERR,
                                 "Cannot ecryptfs_kmalloc a page\n");
                 goto out_dput;
         }
-
-        rc = ecryptfs_read_header_region(page_virt, lower_dentry, nd->mnt);
         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
         if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED))
                 ecryptfs_set_default_sizes(crypt_stat);
+        rc = ecryptfs_read_and_validate_header_region(page_virt, lower_dentry,
+                                                      nd->mnt);
         if (rc) {
-                rc = 0;
-                ecryptfs_printk(KERN_WARNING, "Error reading header region;"
-                                " assuming unencrypted\n");
-        } else {
-                if (!contains_ecryptfs_marker(page_virt
-                                              + ECRYPTFS_FILE_SIZE_BYTES)) {
+                rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
+                if (rc) {
+                        printk(KERN_DEBUG "Valid metadata not found in header "
+                               "region or xattr region; treating file as "
+                               "unencrypted\n");
+                        rc = 0;
                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
                         goto out;
                 }
-                memcpy(&file_size, page_virt, sizeof(file_size));
-                file_size = be64_to_cpu(file_size);
-                i_size_write(dentry->d_inode, (loff_t)file_size);
+                crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
         }
+        memcpy(&file_size, page_virt, sizeof(file_size));
+        file_size = be64_to_cpu(file_size);
+        i_size_write(dentry->d_inode, (loff_t)file_size);
         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
         goto out;
 
@@ -781,20 +784,26 @@ int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
                         goto out_fput;
                 }
                 i_size_write(inode, new_length);
-                rc = ecryptfs_write_inode_size_to_header(lower_file,
-                                                         lower_dentry->d_inode,
-                                                         inode);
+                rc = ecryptfs_write_inode_size_to_metadata(
+                        lower_file, lower_dentry->d_inode, inode, dentry,
+                        ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
                 if (rc) {
-                        ecryptfs_printk(KERN_ERR,
-                                        "Problem with ecryptfs_write"
-                                        "_inode_size\n");
+                        printk(KERN_ERR "Problem with "
+                               "ecryptfs_write_inode_size_to_metadata; "
+                               "rc = [%d]\n", rc);
                         goto out_fput;
                 }
         } else { /* new_length < i_size_read(inode) */
                 vmtruncate(inode, new_length);
-                ecryptfs_write_inode_size_to_header(lower_file,
-                                                    lower_dentry->d_inode,
-                                                    inode);
+                rc = ecryptfs_write_inode_size_to_metadata(
+                        lower_file, lower_dentry->d_inode, inode, dentry,
+                        ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
+                if (rc) {
+                        printk(KERN_ERR "Problem with "
+                               "ecryptfs_write_inode_size_to_metadata; "
+                               "rc = [%d]\n", rc);
+                        goto out_fput;
+                }
                 /* We are reducing the size of the ecryptfs file, and need to
                  * know if we need to reduce the size of the lower file. */
                 lower_size_before_truncate =
@@ -881,7 +890,7 @@ out:
         return rc;
 }
 
-static int
+int
 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
                   size_t size, int flags)
 {
@@ -901,7 +910,7 @@ out:
         return rc;
 }
 
-static ssize_t
+ssize_t
 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
                   size_t size)
 {
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index a3efdccbbcc8..26fe405a5763 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -3,7 +3,7 @@
  *
  * Copyright (C) 1997-2003 Erez Zadok
  * Copyright (C) 2001-2003 Stony Brook University
- * Copyright (C) 2004-2006 International Business Machines Corp.
+ * Copyright (C) 2004-2007 International Business Machines Corp.
  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  *              Michael C. Thompson <mcthomps@us.ibm.com>
  *              Tyler Hicks <tyhicks@ou.edu>
@@ -642,6 +642,11 @@ static struct ecryptfs_cache_info {
                 .size = PAGE_CACHE_SIZE,
         },
         {
+                .cache = &ecryptfs_xattr_cache,
+                .name = "ecryptfs_xattr_cache",
+                .size = PAGE_CACHE_SIZE,
+        },
+        {
                 .cache = &ecryptfs_lower_page_cache,
                 .name = "ecryptfs_lower_page_cache",
                 .size = PAGE_CACHE_SIZE,
diff --git a/fs/ecryptfs/messaging.c b/fs/ecryptfs/messaging.c
index e8ba6278ad2c..47d7e7b611f7 100644
--- a/fs/ecryptfs/messaging.c
+++ b/fs/ecryptfs/messaging.c
@@ -22,16 +22,18 @@
 
 #include "ecryptfs_kernel.h"
 
-LIST_HEAD(ecryptfs_msg_ctx_free_list);
-LIST_HEAD(ecryptfs_msg_ctx_alloc_list);
-struct mutex ecryptfs_msg_ctx_lists_mux;
+static LIST_HEAD(ecryptfs_msg_ctx_free_list);
+static LIST_HEAD(ecryptfs_msg_ctx_alloc_list);
+static struct mutex ecryptfs_msg_ctx_lists_mux;
 
-struct hlist_head *ecryptfs_daemon_id_hash;
-struct mutex ecryptfs_daemon_id_hash_mux;
-int ecryptfs_hash_buckets;
+static struct hlist_head *ecryptfs_daemon_id_hash;
+static struct mutex ecryptfs_daemon_id_hash_mux;
+static int ecryptfs_hash_buckets;
+#define ecryptfs_uid_hash(uid) \
+        hash_long((unsigned long)uid, ecryptfs_hash_buckets)
 
-unsigned int ecryptfs_msg_counter;
-struct ecryptfs_msg_ctx *ecryptfs_msg_ctx_arr;
+static unsigned int ecryptfs_msg_counter;
+static struct ecryptfs_msg_ctx *ecryptfs_msg_ctx_arr;
 
 /**
  * ecryptfs_acquire_free_msg_ctx
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index 0af3aa3b4b3e..ba3650d03c48 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -6,7 +6,7 @@
  *
  * Copyright (C) 1997-2003 Erez Zadok
  * Copyright (C) 2001-2003 Stony Brook University
- * Copyright (C) 2004-2006 International Business Machines Corp.
+ * Copyright (C) 2004-2007 International Business Machines Corp.
  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  *
  * This program is free software; you can redistribute it and/or
@@ -308,6 +308,9 @@ out:
         return rc;
 }
 
+/**
+ * Called with lower inode mutex held.
+ */
 static int fill_zeros_to_end_of_page(struct page *page, unsigned int to)
 {
         struct inode *inode = page->mapping->host;
@@ -407,10 +410,9 @@ static void ecryptfs_unmap_and_release_lower_page(struct page *lower_page)
  *
  * Returns zero on success; non-zero on error.
  */
-int
-ecryptfs_write_inode_size_to_header(struct file *lower_file,
-                                    struct inode *lower_inode,
-                                    struct inode *inode)
+static int ecryptfs_write_inode_size_to_header(struct file *lower_file,
+                                               struct inode *lower_inode,
+                                               struct inode *inode)
 {
         int rc = 0;
         struct page *header_page;
@@ -442,6 +444,80 @@ out:
         return rc;
 }
 
+static int ecryptfs_write_inode_size_to_xattr(struct inode *lower_inode,
+                                              struct inode *inode,
+                                              struct dentry *ecryptfs_dentry,
+                                              int lower_i_mutex_held)
+{
+        ssize_t size;
+        void *xattr_virt;
+        struct dentry *lower_dentry;
+        u64 file_size;
+        int rc;
+
+        xattr_virt = kmem_cache_alloc(ecryptfs_xattr_cache, GFP_KERNEL);
+        if (!xattr_virt) {
+                printk(KERN_ERR "Out of memory whilst attempting to write "
+                       "inode size to xattr\n");
+                rc = -ENOMEM;
+                goto out;
+        }
+        lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
+        if (!lower_dentry->d_inode->i_op->getxattr) {
+                printk(KERN_WARNING
+                       "No support for setting xattr in lower filesystem\n");
+                rc = -ENOSYS;
+                kmem_cache_free(ecryptfs_xattr_cache, xattr_virt);
+                goto out;
+        }
+        if (!lower_i_mutex_held)
+                mutex_lock(&lower_dentry->d_inode->i_mutex);
+        size = lower_dentry->d_inode->i_op->getxattr(lower_dentry,
+                                                     ECRYPTFS_XATTR_NAME,
+                                                     xattr_virt,
+                                                     PAGE_CACHE_SIZE);
+        if (!lower_i_mutex_held)
+                mutex_unlock(&lower_dentry->d_inode->i_mutex);
+        if (size < 0)
+                size = 8;
+        file_size = (u64)i_size_read(inode);
+        file_size = cpu_to_be64(file_size);
+        memcpy(xattr_virt, &file_size, sizeof(u64));
+        if (!lower_i_mutex_held)
+                mutex_lock(&lower_dentry->d_inode->i_mutex);
+        rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry,
+                                                   ECRYPTFS_XATTR_NAME,
+                                                   xattr_virt, size, 0);
+        if (!lower_i_mutex_held)
+                mutex_unlock(&lower_dentry->d_inode->i_mutex);
+        if (rc)
+                printk(KERN_ERR "Error whilst attempting to write inode size "
+                       "to lower file xattr; rc = [%d]\n", rc);
+        kmem_cache_free(ecryptfs_xattr_cache, xattr_virt);
+out:
+        return rc;
+}
+
+int
+ecryptfs_write_inode_size_to_metadata(struct file *lower_file,
+                                      struct inode *lower_inode,
+                                      struct inode *inode,
+                                      struct dentry *ecryptfs_dentry,
+                                      int lower_i_mutex_held)
+{
+        struct ecryptfs_crypt_stat *crypt_stat;
+
+        crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
+        if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
+                return ecryptfs_write_inode_size_to_xattr(lower_inode, inode,
+                                                          ecryptfs_dentry,
+                                                          lower_i_mutex_held);
+        else
+                return ecryptfs_write_inode_size_to_header(lower_file,
+                                                           lower_inode,
+                                                           inode);
+}
+
 int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode,
                             struct file *lower_file,
                             unsigned long lower_page_index, int byte_offset,
@@ -528,6 +604,8 @@ out:
         return rc;
 }
 
+struct kmem_cache *ecryptfs_xattr_cache;
+
 /**
  * ecryptfs_commit_write
  * @file: The eCryptfs file object
@@ -581,7 +659,6 @@ static int ecryptfs_commit_write(struct file *file, struct page *page,
                                 "index [0x%.16x])\n", page->index);
                 goto out;
         }
-        rc = 0;
         inode->i_blocks = lower_inode->i_blocks;
         pos = (page->index << PAGE_CACHE_SHIFT) + to;
         if (pos > i_size_read(inode)) {
@@ -589,7 +666,12 @@ static int ecryptfs_commit_write(struct file *file, struct page *page,
                 ecryptfs_printk(KERN_DEBUG, "Expanded file size to "
                                 "[0x%.16x]\n", i_size_read(inode));
         }
-        ecryptfs_write_inode_size_to_header(lower_file, lower_inode, inode);
+        rc = ecryptfs_write_inode_size_to_metadata(lower_file, lower_inode,
+                                                   inode, file->f_dentry,
+                                                   ECRYPTFS_LOWER_I_MUTEX_HELD);
+        if (rc)
+                printk(KERN_ERR "Error writing inode size to metadata; "
+                       "rc = [%d]\n", rc);
         lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
         mark_inode_dirty_sync(inode);
 out: