eCryptfs: Allocate a variable number of pages for file headers

[cascardo/linux.git] / fs / ecryptfs / crypto.c

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index bdca1f4..75bee99 100644 (file)
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1324,14 +1324,13 @@ static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
 }
 
 static int
-ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
-                                   struct dentry *ecryptfs_dentry,
-                                   char *virt)
+ecryptfs_write_metadata_to_contents(struct dentry *ecryptfs_dentry,
+                                   char *virt, size_t virt_len)
 {
        int rc;
 
        rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, virt,
-                                 0, crypt_stat->num_header_bytes_at_front);
+                                 0, virt_len);
        if (rc)
                printk(KERN_ERR "%s: Error attempting to write header "
                       "information to lower file; rc = [%d]\n", __func__,
@@ -1341,7 +1340,6 @@ ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
 
 static int
 ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
-                                struct ecryptfs_crypt_stat *crypt_stat,
                                 char *page_virt, size_t size)
 {
        int rc;
@@ -1351,6 +1349,17 @@ ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
        return rc;
 }
 
+static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
+                                              unsigned int order)
+{
+       struct page *page;
+
+       page = alloc_pages(gfp_mask | __GFP_ZERO, order);
+       if (page)
+               return (unsigned long) page_address(page);
+       return 0;
+}
+
 /**
  * ecryptfs_write_metadata
  * @ecryptfs_dentry: The eCryptfs dentry
@@ -1367,7 +1376,9 @@ int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
 {
        struct ecryptfs_crypt_stat *crypt_stat =
                &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
+       unsigned int order;
        char *virt;
+       size_t virt_len;
        size_t size = 0;
        int rc = 0;
 
@@ -1383,33 +1394,35 @@ int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
                rc = -EINVAL;
                goto out;
        }
+       virt_len = crypt_stat->num_header_bytes_at_front;
+       order = get_order(virt_len);
        /* Released in this function */
-       virt = (char *)get_zeroed_page(GFP_KERNEL);
+       virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
        if (!virt) {
                printk(KERN_ERR "%s: Out of memory\n", __func__);
                rc = -ENOMEM;
                goto out;
        }
-       rc = ecryptfs_write_headers_virt(virt, PAGE_CACHE_SIZE, &size,
-                                        crypt_stat, ecryptfs_dentry);
+       rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
+                                        ecryptfs_dentry);
        if (unlikely(rc)) {
                printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
                       __func__, rc);
                goto out_free;
        }
        if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
-               rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry,
-                                                     crypt_stat, virt, size);
+               rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt,
+                                                     size);
        else
-               rc = ecryptfs_write_metadata_to_contents(crypt_stat,
-                                                        ecryptfs_dentry, virt);
+               rc = ecryptfs_write_metadata_to_contents(ecryptfs_dentry, virt,
+                                                        virt_len);
        if (rc) {
                printk(KERN_ERR "%s: Error writing metadata out to lower file; "
                       "rc = [%d]\n", __func__, rc);
                goto out_free;
        }
 out_free:
-       free_page((unsigned long)virt);
+       free_pages((unsigned long)virt, order);
 out:
        return rc;
 }