xfs: Check the return value of xfs_buf_read() for NULL

Check the return value of xfs_buf_read() for NULL and return ENOMEM
if it is NULL.  This is necessary in a few spots to avoid subsequent
code blindly dereferencing the null buffer pointer.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Alex Elder <aelder@sgi.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
index dd05360ad56f..2a432d00d4c1 100644
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -83,6 +83,8 @@ xfs_readlink_bmap(
 
                 bp = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt),
                                   XBF_LOCK | XBF_MAPPED | XBF_DONT_BLOCK);
+                if (!bp)
+                        return XFS_ERROR(ENOMEM);
                 error = xfs_buf_geterror(bp);
                 if (error) {
                         xfs_ioerror_alert("xfs_readlink",