Commit b1091873 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Tyler Hicks
Browse files

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: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarTyler Hicks <code@tyhicks.com>
parent 8f613643

fs/ecryptfs/inode.c

+60 −55
Original line number Diff line number Diff line
@@ -725,46 +725,51 @@ 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));

		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);

		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;
@@ -773,26 +778,26 @@ static int truncate_upper(struct dentry *dentry, struct iattr *ia, 
			rc = -ENOMEM;

			goto out;

		}

			rc = ecryptfs_write(inode, zeros_virt,

					    ia->ia_size, num_zeros);

		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);

			pr_err("Error attempting to zero out the remainder of the end page on reducing truncate; rc = [%d]\n",

				rc);

			goto out;

		}

	}

	truncate_setsize(inode, ia->ia_size);

	rc = ecryptfs_write_inode_size_to_metadata(inode);

	if (rc) {

			printk(KERN_ERR	"Problem with "

			       "ecryptfs_write_inode_size_to_metadata; "

			       "rc = [%d]\n", 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. */



	/*

	 * 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 =
@@ -800,7 +805,7 @@ static int truncate_upper(struct dentry *dentry, struct iattr *ia, 
	if (lower_size_after_truncate < lower_size_before_truncate) {

		lower_ia->ia_size = lower_size_after_truncate;

		lower_ia->ia_valid |= ATTR_SIZE;

		} else

	} else {

		lower_ia->ia_valid &= ~ATTR_SIZE;

	}

out: