[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>

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index 26c346d9de513e3e241eca9f4d6956cb16da0333..1f38b528f0bd43855109abc16223c31f7fa82a59 100644 (file)
--- 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;