Commit e836ec18 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Tyler Hicks
Browse files

ecryptfs: keep the lower iattr contained in truncate_upper 



Currently the two callers of truncate_upper handle passing information
very differently.  ecryptfs_truncate passes a zeroed lower_ia and expects
truncate_upper to fill it in from the upper ia created just for that,
while ecryptfs_setattr passes a fully initialized lower_ia copied from
the upper one.  Both of them then call notify_change on the lower_ia.

Switch to only passing the upper ia, and derive the lower ia from it
inside truncate_upper, and call notify_change inside the function itself.
Because the old name is misleading now, rename the resulting function to
__ecryptfs_truncate as it deals with both the lower and upper inodes.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarTyler Hicks <code@tyhicks.com>
parent 5d1f0e8c

fs/ecryptfs/inode.c

+36 −46
Original line number Diff line number Diff line
@@ -721,36 +721,33 @@ upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat, 
}



/**

 * truncate_upper

 * __ecryptfs_truncate

 * @dentry: The ecryptfs layer dentry

 * @ia: Address of the ecryptfs inode's attributes

 * @lower_ia: Address of the lower inode's attributes

 *

 * Function to handle truncations modifying the size of the file. Note

 * that the file sizes are interpolated. When expanding, we are simply

 * writing strings of 0's out. When truncating, we truncate the upper

 * inode and update the lower_ia according to the page index

 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,

 * the caller must use lower_ia in a call to notify_change() to perform

 * the truncation of the lower inode.

 * Handle truncations modifying the size of the file.  Note that the file sizes

 * are interpolated.  When expanding, we are simply writing strings of 0's out.

 * When truncating, we truncate the upper inode and update the lower_ia

 * according to the page index interpolations.

 *

 * Returns zero on success; non-zero otherwise

 */

static int truncate_upper(struct dentry *dentry, struct iattr *ia,

			  struct iattr *lower_ia)

static int __ecryptfs_truncate(struct dentry *dentry, const struct iattr *ia)

{

	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);

	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;

	struct iattr lower_ia;

	size_t num_zeros;

	int rc;



	if (unlikely((ia->ia_size == i_size))) {

		lower_ia->ia_valid &= ~ATTR_SIZE;

	ecryptfs_iattr_to_lower(&lower_ia, ia);



	if (unlikely((ia->ia_size == i_size)))

		return 0;

	}



	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;

	lower_size_before_truncate =
@@ -783,15 +780,13 @@ static int truncate_upper(struct dentry *dentry, struct iattr *ia, 
		 * new end of the file.

		 */

		rc = ecryptfs_write(inode, zero, ia->ia_size - 1, 1);

		lower_ia->ia_valid &= ~ATTR_SIZE;

		goto out;

	}



	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;

		lower_ia.ia_size = ia->ia_size;

		goto set_size;

	}



	/*
@@ -821,12 +816,15 @@ static int truncate_upper(struct dentry *dentry, struct iattr *ia, 
	 * We are reducing the size of the ecryptfs file, and need to know if we

	 * need to reduce the size of the lower file.

	 */

	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;

	}

	if (lower_size_after_truncate >= lower_size_before_truncate)

		goto out;



	lower_ia.ia_size = lower_size_after_truncate;

set_size:

	lower_ia.ia_valid |= ATTR_SIZE;

	inode_lock(d_inode(lower_dentry));

	rc = notify_change(&nop_mnt_idmap, lower_dentry, &lower_ia, NULL);

	inode_unlock(d_inode(lower_dentry));

out:

	ecryptfs_put_lower_file(inode);

	return rc;
@@ -844,20 +842,12 @@ static int truncate_upper(struct dentry *dentry, struct iattr *ia, 
 */

int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)

{

	struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };

	struct iattr lower_ia = { .ia_valid = 0 };

	int rc;



	rc = truncate_upper(dentry, &ia, &lower_ia);

	if (!rc && lower_ia.ia_valid & ATTR_SIZE) {

		struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);

	const struct iattr ia = {

		.ia_valid	= ATTR_SIZE,

		.ia_size	= new_length,

	};



		inode_lock(d_inode(lower_dentry));

		rc = notify_change(&nop_mnt_idmap, lower_dentry,

				   &lower_ia, NULL);

		inode_unlock(d_inode(lower_dentry));

	}

	return rc;

	return __ecryptfs_truncate(dentry, &ia);

}



static int
@@ -887,7 +877,6 @@ static int ecryptfs_setattr(struct mnt_idmap *idmap, 
	struct inode *inode = d_inode(dentry);

	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);

	struct inode *lower_inode = ecryptfs_inode_to_lower(inode);

	struct iattr lower_ia;

	struct ecryptfs_crypt_stat *crypt_stat;

	int rc;
@@ -935,17 +924,18 @@ static int ecryptfs_setattr(struct mnt_idmap *idmap, 
	if (rc)

		goto out;



	ecryptfs_iattr_to_lower(&lower_ia, ia);

	if (ia->ia_valid & ATTR_SIZE) {

		rc = truncate_upper(dentry, ia, &lower_ia);

		if (rc < 0)

			goto out;

	}

		rc = __ecryptfs_truncate(dentry, ia);

	} else {

		struct iattr lower_ia;



		ecryptfs_iattr_to_lower(&lower_ia, ia);



		inode_lock(d_inode(lower_dentry));

	rc = notify_change(&nop_mnt_idmap, lower_dentry, &lower_ia, NULL);

		rc = notify_change(&nop_mnt_idmap, lower_dentry, &lower_ia,

				NULL);

		inode_unlock(d_inode(lower_dentry));

	}

out:

	fsstack_copy_attr_all(inode, lower_inode);

	return rc;