On 5/4/06, Phillip Hellewell <[email protected]> wrote:
+/**
+ * Get one page from cache or lower f/s, return error otherwise.
+ *
+ * @return Unlocked and up-to-date page (if ok), with increased
+ * refcnt.
+ */
+static struct page *ecryptfs_get1page(struct file *file, int index)
+{
+ struct page *page;
+ struct dentry *dentry;
+ struct inode *inode;
+ struct address_space *mapping;
+ int rc;
+
+ ecryptfs_printk(KERN_DEBUG, "Enter\n");
+ dentry = file->f_dentry;
+ inode = dentry->d_inode;
+ mapping = inode->i_mapping;
+ page = read_cache_page(mapping, index,
+ (filler_t *)mapping->a_ops->readpage,
+ (void *)file);
+ if (IS_ERR(page))
+ goto out;
+ wait_on_page_locked(page);
+ if (!PageUptodate(page)) {
+ lock_page(page);
+ rc = mapping->a_ops->readpage(file, page);
What's the purpose of this second read?
+ if (rc) {
+ page = ERR_PTR(rc);
+ goto out;
+ }
+ wait_on_page_locked(page);
+ if (!PageUptodate(page)) {
+ page = ERR_PTR(-EIO);
+ goto out;
+ }
+ }
+out:
+ ecryptfs_printk(KERN_DEBUG, "Exit\n");
+ return page;
+}
[snip]
+/**
+ * Reads the data from the lower file file at index lower_page_index
+ * and copies that data into page.
+ *
+ * @param page Page to fill
+ * @param lower_page_index Index of the page in the lower file to get
+ */
+int ecryptfs_do_readpage(struct file *file, struct page *page,
+ pgoff_t lower_page_index)
+{
+ int rc = -EIO;
+ struct dentry *dentry;
+ struct file *lower_file;
+ struct dentry *lower_dentry;
+ struct inode *inode;
+ struct inode *lower_inode;
+ char *page_data;
+ struct page *lower_page = NULL;
+ char *lower_page_data;
+ struct address_space_operations *lower_a_ops;
+
+ ecryptfs_printk(KERN_DEBUG, "Enter; lower_page_index = [0x%.16x]\n",
+ lower_page_index);
+ dentry = file->f_dentry;
+ if (NULL == ECRYPTFS_FILE_TO_PRIVATE_SM(file)) {
+ rc = -ENOENT;
+ ecryptfs_printk(KERN_ERR, "No lower file info\n");
+ goto out;
+ }
+ lower_file = ECRYPTFS_FILE_TO_LOWER(file);
+ lower_dentry = ECRYPTFS_DENTRY_TO_LOWER(dentry);
+ inode = dentry->d_inode;
+ lower_inode = ECRYPTFS_INODE_TO_LOWER(inode);
+ lower_a_ops = lower_inode->i_mapping->a_ops;
+ lower_page = read_cache_page(lower_inode->i_mapping, lower_page_index,
+ (filler_t *)lower_a_ops->readpage,
+ (void *)lower_file);
+ if (IS_ERR(lower_page)) {
+ rc = PTR_ERR(lower_page);
+ lower_page = NULL;
+ ecryptfs_printk(KERN_ERR, "Error reading from page cache\n");
+ goto out;
+ }
+ wait_on_page_locked(lower_page);
+ if (!PageUptodate(lower_page)) {
And here?
+ lock_page(lower_page);
+ rc = lower_a_ops->readpage(lower_file, lower_page);
+ if (rc) {
+ lower_page = NULL;
+ rc = -EIO;
+ ecryptfs_printk(KERN_ERR, "Error reading lower "
+ "page at index=[0x%.16x]\n",
+ lower_page_index);
+ goto out;
+ }
+ wait_on_page_locked(lower_page);
+ if (!PageUptodate(lower_page)) {
+ rc = -EIO;
+ ecryptfs_printk(KERN_ERR, "Error reading lower "
+ "page at index=[0x%.16x]\n",
+ lower_page_index);
+ goto out;
+ }
+ }
-
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