eCryptfs: Cleanup and optimize ecryptfs_lookup_interpose()
ecryptfs_lookup_interpose() has turned into spaghetti code over the
years. This is an effort to clean it up.
- Shorten overly descriptive variable names such as ecryptfs_dentry
- Simplify gotos and error paths
- Create helper function for reading plaintext i_size from metadata
It also includes an optimization when reading i_size from the metadata.
A complete page-sized kmem_cache_alloc() was being done to read in 16
bytes of metadata. The buffer for that is now statically declared.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index f0ad965..7349ade 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -307,105 +307,90 @@
return rc;
}
-/**
- * ecryptfs_lookup_interpose - Dentry interposition for a lookup
- */
-static int ecryptfs_lookup_interpose(struct dentry *ecryptfs_dentry,
- struct dentry *lower_dentry,
- struct inode *ecryptfs_dir_inode)
+static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
{
- struct dentry *lower_dir_dentry;
- struct vfsmount *lower_mnt;
- struct inode *inode, *lower_inode;
struct ecryptfs_crypt_stat *crypt_stat;
- char *page_virt = NULL;
- int put_lower = 0, rc = 0;
+ int rc;
- lower_dir_dentry = lower_dentry->d_parent;
- lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
- ecryptfs_dentry->d_parent));
- lower_inode = lower_dentry->d_inode;
- fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
- BUG_ON(!lower_dentry->d_count);
- ecryptfs_set_dentry_private(ecryptfs_dentry,
- kmem_cache_alloc(ecryptfs_dentry_info_cache,
- GFP_KERNEL));
- if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) {
- rc = -ENOMEM;
- printk(KERN_ERR "%s: Out of memory whilst attempting "
- "to allocate ecryptfs_dentry_info struct\n",
- __func__);
- goto out_put;
- }
- ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry);
- ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt);
- if (!lower_dentry->d_inode) {
- /* We want to add because we couldn't find in lower */
- d_add(ecryptfs_dentry, NULL);
- goto out;
- }
- inode = __ecryptfs_get_inode(lower_inode, ecryptfs_dir_inode->i_sb);
- if (IS_ERR(inode)) {
- rc = PTR_ERR(inode);
- printk(KERN_ERR "%s: Error interposing; rc = [%d]\n",
- __func__, rc);
- goto out;
- }
- if (!S_ISREG(inode->i_mode)) {
- if (inode->i_state & I_NEW)
- unlock_new_inode(inode);
- d_add(ecryptfs_dentry, inode);
- goto out;
- }
- /* Released in this function */
- page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER);
- if (!page_virt) {
- printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n",
- __func__);
- rc = -ENOMEM;
- make_bad_inode(inode);
- goto out;
- }
- rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
+ rc = ecryptfs_get_lower_file(dentry, inode);
if (rc) {
printk(KERN_ERR "%s: Error attempting to initialize "
"the lower file for the dentry with name "
"[%s]; rc = [%d]\n", __func__,
- ecryptfs_dentry->d_name.name, rc);
- make_bad_inode(inode);
- goto out_free_kmem;
+ dentry->d_name.name, rc);
+ return rc;
}
- put_lower = 1;
+
crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
/* TODO: lock for crypt_stat comparison */
if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
- ecryptfs_set_default_sizes(crypt_stat);
- rc = ecryptfs_read_and_validate_header_region(page_virt, inode);
+ ecryptfs_set_default_sizes(crypt_stat);
+
+ rc = ecryptfs_read_and_validate_header_region(inode);
+ ecryptfs_put_lower_file(inode);
if (rc) {
- memset(page_virt, 0, PAGE_CACHE_SIZE);
- rc = ecryptfs_read_and_validate_xattr_region(page_virt,
- inode);
- if (rc) {
- rc = 0;
- goto unlock_inode;
- }
- crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
+ rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
+ if (!rc)
+ crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
}
- ecryptfs_i_size_init(page_virt, inode);
-unlock_inode:
+
+ /* Must return 0 to allow non-eCryptfs files to be looked up, too */
+ return 0;
+}
+
+/**
+ * ecryptfs_lookup_interpose - Dentry interposition for a lookup
+ */
+static int ecryptfs_lookup_interpose(struct dentry *dentry,
+ struct dentry *lower_dentry,
+ struct inode *dir_inode)
+{
+ struct inode *inode, *lower_inode = lower_dentry->d_inode;
+ struct ecryptfs_dentry_info *dentry_info;
+ struct vfsmount *lower_mnt;
+ int rc = 0;
+
+ lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
+ fsstack_copy_attr_atime(dir_inode, lower_dentry->d_parent->d_inode);
+ BUG_ON(!lower_dentry->d_count);
+
+ dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
+ ecryptfs_set_dentry_private(dentry, dentry_info);
+ if (!dentry_info) {
+ printk(KERN_ERR "%s: Out of memory whilst attempting "
+ "to allocate ecryptfs_dentry_info struct\n",
+ __func__);
+ dput(lower_dentry);
+ mntput(lower_mnt);
+ d_drop(dentry);
+ return -ENOMEM;
+ }
+ ecryptfs_set_dentry_lower(dentry, lower_dentry);
+ ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
+
+ if (!lower_dentry->d_inode) {
+ /* We want to add because we couldn't find in lower */
+ d_add(dentry, NULL);
+ return 0;
+ }
+ inode = __ecryptfs_get_inode(lower_inode, dir_inode->i_sb);
+ if (IS_ERR(inode)) {
+ printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
+ __func__, PTR_ERR(inode));
+ return PTR_ERR(inode);
+ }
+ if (S_ISREG(inode->i_mode)) {
+ rc = ecryptfs_i_size_read(dentry, inode);
+ if (rc) {
+ make_bad_inode(inode);
+ return rc;
+ }
+ }
+
if (inode->i_state & I_NEW)
unlock_new_inode(inode);
- d_add(ecryptfs_dentry, inode);
-out_free_kmem:
- kmem_cache_free(ecryptfs_header_cache_2, page_virt);
- goto out;
-out_put:
- dput(lower_dentry);
- mntput(lower_mnt);
- d_drop(ecryptfs_dentry);
-out:
- if (put_lower)
- ecryptfs_put_lower_file(inode);
+ d_add(dentry, inode);
+
return rc;
}