xfs: do not use unchecked extent indices in xfs_bmap_add_extent_*

Make sure to only call xfs_iext_get_ext after we've validate the
extent index in the various xfs_bmap_add_extent_* helpers.

Based on an earlier patch from Lachlan McIlroy.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Lachlan McIlroy <lmcilroy@redhat.com>
Signed-off-by: Alex Elder <aelder@sgi.com>

1 files changed, 6 insertions, 8 deletions

diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c
index 8f586df8ff8d..130ec4fa5eaf 100644
--- a/fs/xfs/xfs_bmap.c
+++ b/fs/xfs/xfs_bmap.c
@@ -1629,7 +1629,6 @@ xfs_bmap_add_extent_hole_delay(
         xfs_bmbt_irec_t         *new,   /* new data to add to file extents */
         int                     *logflagsp) /* inode logging flags */
 {
-        xfs_bmbt_rec_host_t     *ep;    /* extent record for idx */
         xfs_ifork_t             *ifp;   /* inode fork pointer */
         xfs_bmbt_irec_t         left;   /* left neighbor extent entry */
         xfs_filblks_t           newlen=0;       /* new indirect size */
@@ -1639,7 +1638,6 @@ xfs_bmap_add_extent_hole_delay(
         xfs_filblks_t           temp=0; /* temp for indirect calculations */
 
         ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
-        ep = xfs_iext_get_ext(ifp, *idx);
         state = 0;
         ASSERT(isnullstartblock(new->br_startblock));
 
@@ -1660,7 +1658,7 @@ xfs_bmap_add_extent_hole_delay(
          */
         if (*idx < ip->i_df.if_bytes / (uint)sizeof(xfs_bmbt_rec_t)) {
                 state |= BMAP_RIGHT_VALID;
-                xfs_bmbt_get_all(ep, &right);
+                xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *idx), &right);
 
                 if (isnullstartblock(right.br_startblock))
                         state |= BMAP_RIGHT_DELAY;
@@ -1740,7 +1738,8 @@ xfs_bmap_add_extent_hole_delay(
                 oldlen = startblockval(new->br_startblock) +
                         startblockval(right.br_startblock);
                 newlen = xfs_bmap_worst_indlen(ip, temp);
-                xfs_bmbt_set_allf(ep, new->br_startoff,
+                xfs_bmbt_set_allf(xfs_iext_get_ext(ifp, *idx),
+                        new->br_startoff,
                         nullstartblock((int)newlen), temp, right.br_state);
                 trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);
                 break;
@@ -1780,7 +1779,6 @@ xfs_bmap_add_extent_hole_real(
         int                     *logflagsp, /* inode logging flags */
         int                     whichfork) /* data or attr fork */
 {
-        xfs_bmbt_rec_host_t     *ep;    /* pointer to extent entry ins. point */
         int                     error;  /* error return value */
         int                     i;      /* temp state */
         xfs_ifork_t             *ifp;   /* inode fork pointer */
@@ -1791,7 +1789,6 @@ xfs_bmap_add_extent_hole_real(
 
         ifp = XFS_IFORK_PTR(ip, whichfork);
         ASSERT(*idx <= ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t));
-        ep = xfs_iext_get_ext(ifp, *idx);
         state = 0;
 
         if (whichfork == XFS_ATTR_FORK)
@@ -1813,7 +1810,7 @@ xfs_bmap_add_extent_hole_real(
          */
         if (*idx < ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t)) {
                 state |= BMAP_RIGHT_VALID;
-                xfs_bmbt_get_all(ep, &right);
+                xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *idx), &right);
                 if (isnullstartblock(right.br_startblock))
                         state |= BMAP_RIGHT_DELAY;
         }
@@ -1925,7 +1922,8 @@ xfs_bmap_add_extent_hole_real(
                  * Merge the new allocation with the right neighbor.
                  */
                 trace_xfs_bmap_pre_update(ip, *idx, state, _THIS_IP_);
-                xfs_bmbt_set_allf(ep, new->br_startoff, new->br_startblock,
+                xfs_bmbt_set_allf(xfs_iext_get_ext(ifp, *idx),
+                        new->br_startoff, new->br_startblock,
                         new->br_blockcount + right.br_blockcount,
                         right.br_state);
                 trace_xfs_bmap_post_update(ip, *idx, state, _THIS_IP_);