[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>

1 files changed, 35 insertions, 26 deletions

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)
 {