2 files changed, 10 insertions, 3 deletions

diff --git a/Documentation/filesystems/btrfs.txt b/Documentation/filesystems/btrfs.txt
index e87609a4e21c..7254cf501391 100644
--- a/Documentation/filesystems/btrfs.txt
+++ b/Documentation/filesystems/btrfs.txt
@@ -98,9 +98,12 @@ Options with (*) are default options and will not show in the mount options.
         can be avoided.  Especially useful when trying to mount a multi-device
         setup as root.  May be specified multiple times for multiple devices.
 
+  nodiscard(*)
   discard
-        Issue frequent commands to let the block device reclaim space freed by
-        the filesystem.  This is useful for SSD devices, thinly provisioned
+        Disable/enable discard mount option.
+        Discard issues frequent commands to let the block device reclaim space
+        freed by the filesystem.
+        This is useful for SSD devices, thinly provisioned
         LUNs and virtual machine images, but may have a significant
         performance impact.  (The fstrim command is also available to
         initiate batch trims from userspace).
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 44513f3fbdc1..e15377035dd5 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -323,7 +323,7 @@ enum {
         Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
         Opt_check_integrity, Opt_check_integrity_including_extent_data,
         Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
-        Opt_commit_interval, Opt_barrier, Opt_nodefrag,
+        Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
         Opt_err,
 };
 
@@ -351,6 +351,7 @@ static match_table_t tokens = {
         {Opt_flushoncommit, "flushoncommit"},
         {Opt_ratio, "metadata_ratio=%d"},
         {Opt_discard, "discard"},
+        {Opt_nodiscard, "nodiscard"},
         {Opt_space_cache, "space_cache"},
         {Opt_clear_cache, "clear_cache"},
         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
@@ -575,6 +576,9 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                 case Opt_discard:
                         btrfs_set_opt(info->mount_opt, DISCARD);
                         break;
+                case Opt_nodiscard:
+                        btrfs_clear_opt(info->mount_opt, DISCARD);
+                        break;
                 case Opt_space_cache:
                         btrfs_set_opt(info->mount_opt, SPACE_CACHE);
                         break;