diff options
Diffstat (limited to 'fs/ecryptfs/mmap.c')
| -rw-r--r-- | fs/ecryptfs/mmap.c | 31 |
1 files changed, 20 insertions, 11 deletions
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c index 16a7a555f39..32c5711d79a 100644 --- a/fs/ecryptfs/mmap.c +++ b/fs/ecryptfs/mmap.c @@ -263,14 +263,13 @@ 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, @@ -283,22 +282,32 @@ static int ecryptfs_prepare_write(struct file *file, struct page *page, } 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(page, 0, PAGE_CACHE_SIZE, KM_USER0); } out: return rc; |