1 files changed, 16 insertions, 2 deletions

diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index b0aa59e51fd0..98b9c91fcdf1 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -110,8 +110,10 @@ mempool_t *xfs_ioend_pool;
 #define MNTOPT_GQUOTANOENF "gqnoenforce"/* group quota limit enforcement */
 #define MNTOPT_PQUOTANOENF "pqnoenforce"/* project quota limit enforcement */
 #define MNTOPT_QUOTANOENF  "qnoenforce" /* same as uqnoenforce */
-#define MNTOPT_DELAYLOG   "delaylog"    /* Delayed loging enabled */
-#define MNTOPT_NODELAYLOG "nodelaylog"  /* Delayed loging disabled */
+#define MNTOPT_DELAYLOG    "delaylog"   /* Delayed logging enabled */
+#define MNTOPT_NODELAYLOG  "nodelaylog" /* Delayed logging disabled */
+#define MNTOPT_DISCARD     "discard"    /* Discard unused blocks */
+#define MNTOPT_NODISCARD   "nodiscard"  /* Do not discard unused blocks */
 
 /*
  * Table driven mount option parser.
@@ -355,6 +357,10 @@ xfs_parseargs(
                         mp->m_flags |= XFS_MOUNT_DELAYLOG;
                 } else if (!strcmp(this_char, MNTOPT_NODELAYLOG)) {
                         mp->m_flags &= ~XFS_MOUNT_DELAYLOG;
+                } else if (!strcmp(this_char, MNTOPT_DISCARD)) {
+                        mp->m_flags |= XFS_MOUNT_DISCARD;
+                } else if (!strcmp(this_char, MNTOPT_NODISCARD)) {
+                        mp->m_flags &= ~XFS_MOUNT_DISCARD;
                 } else if (!strcmp(this_char, "ihashsize")) {
                         xfs_warn(mp,
         "ihashsize no longer used, option is deprecated.");
@@ -388,6 +394,13 @@ xfs_parseargs(
                 return EINVAL;
         }
 
+        if ((mp->m_flags & XFS_MOUNT_DISCARD) &&
+            !(mp->m_flags & XFS_MOUNT_DELAYLOG)) {
+                xfs_warn(mp,
+        "the discard option is incompatible with the nodelaylog option");
+                return EINVAL;
+        }
+
 #ifndef CONFIG_XFS_QUOTA
         if (XFS_IS_QUOTA_RUNNING(mp)) {
                 xfs_warn(mp, "quota support not available in this kernel.");
@@ -488,6 +501,7 @@ xfs_showargs(
                 { XFS_MOUNT_FILESTREAMS,        "," MNTOPT_FILESTREAM },
                 { XFS_MOUNT_GRPID,              "," MNTOPT_GRPID },
                 { XFS_MOUNT_DELAYLOG,           "," MNTOPT_DELAYLOG },
+                { XFS_MOUNT_DISCARD,            "," MNTOPT_DISCARD },
                 { 0, NULL }
         };
         static struct proc_xfs_info xfs_info_unset[] = {