NTFS: Change ntfs_attr_make_non_resident to take the attribute value size

      as an extra parameter.  This is needed since we need to know the size
      before we can map the mft record and our callers always know it.  The
      reason we cannot simply read the size from the vfs inode i_size is
      that this is not necessarily uptodate.  This happens when
      ntfs_attr_make_non_resident() is called in the ->truncate call path.

Signed-off-by: Anton Altaparmakov <aia21@cantab.net>

1 files changed, 10 insertions, 3 deletions

diff --git a/fs/ntfs/attrib.c b/fs/ntfs/attrib.c
index 33e689f..380f70a 100644
--- a/fs/ntfs/attrib.c
+++ b/fs/ntfs/attrib.c
@@ -1501,10 +1501,17 @@ int ntfs_resident_attr_value_resize(MFT_RECORD *m, ATTR_RECORD *a,
 /**
  * ntfs_attr_make_non_resident - convert a resident to a non-resident attribute
  * @ni:		ntfs inode describing the attribute to convert
+ * @data_size:	size of the resident data to copy to the non-resident attribute
  *
  * Convert the resident ntfs attribute described by the ntfs inode @ni to a
  * non-resident one.
  *
+ * @data_size must be equal to the attribute value size.  This is needed since
+ * we need to know the size before we can map the mft record and our callers
+ * always know it.  The reason we cannot simply read the size from the vfs
+ * inode i_size is that this is not necessarily uptodate.  This happens when
+ * ntfs_attr_make_non_resident() is called in the ->truncate call path(s).
+ *
  * Return 0 on success and -errno on error.  The following error return codes
  * are defined:
  *	-EPERM	- The attribute is not allowed to be non-resident.
@@ -1525,7 +1532,7 @@ int ntfs_resident_attr_value_resize(MFT_RECORD *m, ATTR_RECORD *a,
  *
  * Locking: - The caller must hold i_sem on the inode.
  */
-int ntfs_attr_make_non_resident(ntfs_inode *ni)
+int ntfs_attr_make_non_resident(ntfs_inode *ni, const u32 data_size)
 {
 	s64 new_size;
 	struct inode *vi = VFS_I(ni);
@@ -1563,7 +1570,7 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni)
 	 * The size needs to be aligned to a cluster boundary for allocation
 	 * purposes.
 	 */
-	new_size = (i_size_read(vi) + vol->cluster_size - 1) &
+	new_size = (data_size + vol->cluster_size - 1) &
 			~(vol->cluster_size - 1);
 	if (new_size > 0) {
 		/*
@@ -1647,7 +1654,7 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni)
 	 * attribute value.
 	 */
 	attr_size = le32_to_cpu(a->data.resident.value_length);
-	BUG_ON(attr_size != i_size_read(vi));
+	BUG_ON(attr_size != data_size);
 	if (page && !PageUptodate(page)) {
 		kaddr = kmap_atomic(page, KM_USER0);
 		memcpy(kaddr, (u8*)a +