ecryptfs: streamline truncate_upper

Use a few strategic gotos to reduce indentation and keep the main flow
outside of branches.  Switch all touched comments to normal kernel style
and avoid breaks in printed strings for all the code touched.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Tyler Hicks <code@tyhicks.com>

Author: Christoph Hellwig

fs/ecryptfs/inode.c

@@ -725,83 +725,88 @@ upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
 			  struct iattr *lower_ia)
 {
-	int rc = 0;
 	struct inode *inode = d_inode(dentry);
 	struct ecryptfs_crypt_stat *crypt_stat;
 	loff_t i_size = i_size_read(inode);
 	loff_t lower_size_before_truncate;
 	loff_t lower_size_after_truncate;
+	size_t num_zeros;
+	int rc;
 
 	if (unlikely((ia->ia_size == i_size))) {
 		lower_ia->ia_valid &= ~ATTR_SIZE;
 		return 0;
 	}
+
 	rc = ecryptfs_get_lower_file(dentry, inode);
 	if (rc)
 		return rc;
-	crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
-	/* Switch on growing or shrinking file */
+
 	if (ia->ia_size > i_size) {
 		char zero[] = { 0x00 };
 
+		/*
+		 * Write a single 0 at the last position of the file; this
+		 * triggers code that will fill in 0's throughout the
+		 * intermediate portion of the previous end of the file and the
+		 * new end of the file.
+		 */
+		rc = ecryptfs_write(inode, zero, ia->ia_size - 1, 1);
 		lower_ia->ia_valid &= ~ATTR_SIZE;
-		/* Write a single 0 at the last position of the file;
-		 * this triggers code that will fill in 0's throughout
-		 * the intermediate portion of the previous end of the
-		 * file and the new and of the file */
-		rc = ecryptfs_write(inode, zero,
-				    (ia->ia_size - 1), 1);
-	} else { /* ia->ia_size < i_size_read(inode) */
-		/* We're chopping off all the pages down to the page
-		 * in which ia->ia_size is located. Fill in the end of
-		 * that page from (ia->ia_size & ~PAGE_MASK) to
-		 * PAGE_SIZE with zeros. */
-		size_t num_zeros = (PAGE_SIZE
-				    - (ia->ia_size & ~PAGE_MASK));
-
-		if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
-			truncate_setsize(inode, ia->ia_size);
-			lower_ia->ia_size = ia->ia_size;
-			lower_ia->ia_valid |= ATTR_SIZE;
-			goto out;
-		}
-		if (num_zeros) {
-			char *zeros_virt;
+		goto out;
+	}
 
-			zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
-			if (!zeros_virt) {
-				rc = -ENOMEM;
-				goto out;
-			}
-			rc = ecryptfs_write(inode, zeros_virt,
-					    ia->ia_size, num_zeros);
-			kfree(zeros_virt);
-			if (rc) {
-				printk(KERN_ERR "Error attempting to zero out "
-				       "the remainder of the end page on "
-				       "reducing truncate; rc = [%d]\n", rc);
-				goto out;
-			}
-		}
+	crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
+	if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
 		truncate_setsize(inode, ia->ia_size);
-		rc = ecryptfs_write_inode_size_to_metadata(inode);
+		lower_ia->ia_size = ia->ia_size;
+		lower_ia->ia_valid |= ATTR_SIZE;
+		goto out;
+	}
+
+	/*
+	 * We're chopping off all the pages down to the page in which
+	 * ia->ia_size is located. Fill in the end of that page from
+	 * (ia->ia_size & ~PAGE_MASK) to PAGE_SIZE with zeros.
+	 */
+	num_zeros = PAGE_SIZE - (ia->ia_size & ~PAGE_MASK);
+	if (num_zeros) {
+		char *zeros_virt;
+
+		zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
+		if (!zeros_virt) {
+			rc = -ENOMEM;
+			goto out;
+		}
+		rc = ecryptfs_write(inode, zeros_virt, ia->ia_size, num_zeros);
+		kfree(zeros_virt);
 		if (rc) {
-			printk(KERN_ERR	"Problem with "
-			       "ecryptfs_write_inode_size_to_metadata; "
-			       "rc = [%d]\n", rc);
+			pr_err("Error attempting to zero out the remainder of the end page on reducing truncate; rc = [%d]\n",
+				rc);
 			goto out;
 		}
-		/* 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 =
-		    upper_size_to_lower_size(crypt_stat, i_size);
-		lower_size_after_truncate =
-		    upper_size_to_lower_size(crypt_stat, ia->ia_size);
-		if (lower_size_after_truncate < lower_size_before_truncate) {
-			lower_ia->ia_size = lower_size_after_truncate;
-			lower_ia->ia_valid |= ATTR_SIZE;
-		} else
-			lower_ia->ia_valid &= ~ATTR_SIZE;
+	}
+	truncate_setsize(inode, ia->ia_size);
+	rc = ecryptfs_write_inode_size_to_metadata(inode);
+	if (rc) {
+		pr_err("Problem with ecryptfs_write_inode_size_to_metadata; rc = [%d]\n",
+			rc);
+		goto out;
+	}
+
+	/*
+	 * 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 =
+		upper_size_to_lower_size(crypt_stat, i_size);
+	lower_size_after_truncate =
+		upper_size_to_lower_size(crypt_stat, ia->ia_size);
+	if (lower_size_after_truncate < lower_size_before_truncate) {
+		lower_ia->ia_size = lower_size_after_truncate;
+		lower_ia->ia_valid |= ATTR_SIZE;
+	} else {
+		lower_ia->ia_valid &= ~ATTR_SIZE;
 	}
 out:
 	ecryptfs_put_lower_file(inode);