* Extend the initialized size of an attribute described by the ntfs inode @ni
* to @new_init_size bytes. This involves zeroing any non-sparse space between
* the old initialized size and @new_init_size both in the page cache and on
- * disk (if relevant complete pages are zeroed in the page cache then these may
- * simply be marked dirty for later writeout). There is one caveat and that is
- * that if any uptodate page cache pages between the old initialized size and
- * the smaller of @new_init_size and the file size (vfs inode->i_size) are in
- * memory, these need to be marked dirty without being zeroed since they could
- * be non-zero due to mmap() based writes.
+ * disk (if relevant complete pages are already uptodate in the page cache then
+ * these are simply marked dirty).
*
* As a side-effect, the file size (vfs inode->i_size) may be incremented as,
* in the resident attribute case, it is tied to the initialized size and, in
* with new data via mmap() based writes, so we cannot just zero it. And since
* POSIX specifies that the behaviour of resizing a file whilst it is mmap()ped
* is unspecified, we choose not to do zeroing and thus we do not need to touch
- * the page at all. For a more detailed explanation see ntfs_truncate() which
- * is in fs/ntfs/inode.c.
+ * the page at all. For a more detailed explanation see ntfs_truncate() in
+ * fs/ntfs/inode.c.
*
- * @cached_page and @lru_pvec are just optimisations for dealing with multiple
+ * @cached_page and @lru_pvec are just optimizations for dealing with multiple
* pages.
*
* Return 0 on success and -errno on error. In the case that an error is
* this is the case, the necessary zeroing will also have happened and that all
* metadata is self-consistent.
*
- * Locking: This function locks the mft record of the base ntfs inode and
- * maintains the lock throughout execution of the function. This is required
- * so that the initialized size of the attribute can be modified safely.
+ * Locking: i_sem on the vfs inode corrseponsind to the ntfs inode @ni must be
+ * held by the caller.
*/
static int ntfs_attr_extend_initialized(ntfs_inode *ni, const s64 new_init_size,
struct page **cached_page, struct pagevec *lru_pvec)
VCN last_vcn;
LCN lcn;
unsigned long flags;
- size_t bytes, iov_ofs;
+ size_t bytes, iov_ofs = 0; /* Offset in the current iovec. */
ssize_t status, written;
unsigned nr_pages;
int err;
last_vcn = -1;
if (likely(nr_segs == 1))
buf = iov->iov_base;
- else
- iov_ofs = 0; /* Offset in the current iovec. */
do {
VCN vcn;
pgoff_t idx, start_idx;