#include <linux/scatterlist.h>
#include "ecryptfs_kernel.h"
-struct kmem_cache *ecryptfs_lower_page_cache;
-
/**
* ecryptfs_get_locked_page
*
struct ecryptfs_crypt_stat *crypt_stat)
{
size_t written;
- int save_num_header_extents_at_front =
- crypt_stat->num_header_extents_at_front;
+ size_t save_num_header_bytes_at_front =
+ crypt_stat->num_header_bytes_at_front;
- crypt_stat->num_header_extents_at_front = 1;
+ crypt_stat->num_header_bytes_at_front =
+ ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
ecryptfs_write_header_metadata(page_virt + 20, crypt_stat, &written);
- crypt_stat->num_header_extents_at_front =
- save_num_header_extents_at_front;
+ crypt_stat->num_header_bytes_at_front =
+ save_num_header_bytes_at_front;
}
/**
loff_t view_extent_num = ((((loff_t)page->index)
* num_extents_per_page)
+ extent_num_in_page);
+ size_t num_header_extents_at_front =
+ (crypt_stat->num_header_bytes_at_front
+ / crypt_stat->extent_size);
- if (view_extent_num < crypt_stat->num_header_extents_at_front) {
+ if (view_extent_num < num_header_extents_at_front) {
/* This is a header extent */
char *page_virt;
} else {
/* This is an encrypted data extent */
loff_t lower_offset =
- ((view_extent_num -
- crypt_stat->num_header_extents_at_front)
- * crypt_stat->extent_size);
+ ((view_extent_num * crypt_stat->extent_size)
+ - crypt_stat->num_header_bytes_at_front);
rc = ecryptfs_read_lower_page_segment(
page, (lower_offset >> PAGE_CACHE_SHIFT),
end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE;
if (to > end_byte_in_page)
end_byte_in_page = to;
- zero_user_page(page, end_byte_in_page,
- PAGE_CACHE_SIZE - end_byte_in_page, KM_USER0);
+ zero_user_segment(page, end_byte_in_page, PAGE_CACHE_SIZE);
out:
return 0;
}
+/* This function must zero any hole we create */
static int ecryptfs_prepare_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
int rc = 0;
+ loff_t prev_page_end_size;
- if (from == 0 && to == PAGE_CACHE_SIZE)
- goto out; /* If we are writing a full page, it will be
- up to date. */
if (!PageUptodate(page)) {
rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
PAGE_CACHE_SIZE,
} else
SetPageUptodate(page);
}
- if (page->index != 0) {
- loff_t end_of_prev_pg_pos =
- (((loff_t)page->index << PAGE_CACHE_SHIFT) - 1);
- if (end_of_prev_pg_pos > i_size_read(page->mapping->host)) {
+ prev_page_end_size = ((loff_t)page->index << PAGE_CACHE_SHIFT);
+
+ /*
+ * If creating a page or more of holes, zero them out via truncate.
+ * Note, this will increase i_size.
+ */
+ if (page->index != 0) {
+ if (prev_page_end_size > i_size_read(page->mapping->host)) {
rc = ecryptfs_truncate(file->f_path.dentry,
- end_of_prev_pg_pos);
+ prev_page_end_size);
if (rc) {
printk(KERN_ERR "Error on attempt to "
"truncate to (higher) offset [%lld];"
- " rc = [%d]\n", end_of_prev_pg_pos, rc);
+ " rc = [%d]\n", prev_page_end_size, rc);
goto out;
}
}
- if (end_of_prev_pg_pos + 1 > i_size_read(page->mapping->host))
- zero_user_page(page, 0, PAGE_CACHE_SIZE, KM_USER0);
+ }
+ /*
+ * Writing to a new page, and creating a small hole from start of page?
+ * Zero it out.
+ */
+ if ((i_size_read(page->mapping->host) == prev_page_end_size) &&
+ (from != 0)) {
+ zero_user(page, 0, PAGE_CACHE_SIZE);
}
out:
return rc;