[XFS] Fix boundary conditions when issuing direct IOs from large userspace

buffers.

SGI-PV: 944820
SGI-Modid: xfs-linux:xfs-kern:24223a

Signed-off-by: Nathan Scott <nathans@sgi.com>

1 files changed, 16 insertions, 12 deletions

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index 26c346d9de51..1f38b528f0bd 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -935,15 +935,18 @@ __linvfs_get_block(
 {
         vnode_t                 *vp = LINVFS_GET_VP(inode);
         xfs_iomap_t             iomap;
+        xfs_off_t               offset;
+        ssize_t                 size;
         int                     retpbbm = 1;
         int                     error;
-        ssize_t                 size;
-        loff_t                  offset = (loff_t)iblock << inode->i_blkbits;
 
-        if (blocks)
-                size = blocks << inode->i_blkbits;
-        else
+        if (blocks) {
+                offset = blocks << inode->i_blkbits;    /* 64 bit goodness */
+                size = (ssize_t) min_t(xfs_off_t, offset, LONG_MAX);
+        } else {
                 size = 1 << inode->i_blkbits;
+        }
+        offset = (xfs_off_t)iblock << inode->i_blkbits;
 
         VOP_BMAP(vp, offset, size,
                 create ? flags : BMAPI_READ, &iomap, &retpbbm, error);
@@ -954,8 +957,8 @@ __linvfs_get_block(
                 return 0;
 
         if (iomap.iomap_bn != IOMAP_DADDR_NULL) {
-                xfs_daddr_t             bn;
-                loff_t                  delta;
+                xfs_daddr_t     bn;
+                xfs_off_t       delta;
 
                 /* For unwritten extents do not report a disk address on
                  * the read case (treat as if we're reading into a hole).
@@ -987,9 +990,8 @@ __linvfs_get_block(
          */
         if (create &&
             ((!buffer_mapped(bh_result) && !buffer_uptodate(bh_result)) ||
-             (offset >= i_size_read(inode)) || (iomap.iomap_flags & IOMAP_NEW))) {
+             (offset >= i_size_read(inode)) || (iomap.iomap_flags & IOMAP_NEW)))
                 set_buffer_new(bh_result);
-        }
 
         if (iomap.iomap_flags & IOMAP_DELAY) {
                 BUG_ON(direct);
@@ -1001,9 +1003,11 @@ __linvfs_get_block(
         }
 
         if (blocks) {
-                bh_result->b_size = (ssize_t)min(
-                        (loff_t)(iomap.iomap_bsize - iomap.iomap_delta),
-                        (loff_t)(blocks << inode->i_blkbits));
+                ASSERT(iomap.iomap_bsize - iomap.iomap_delta > 0);
+                offset = min_t(xfs_off_t,
+                                iomap.iomap_bsize - iomap.iomap_delta,
+                                blocks << inode->i_blkbits);
+                bh_result->b_size = (u32) min_t(xfs_off_t, UINT_MAX, offset);
         }
 
         return 0;