Btrfs: put ENOSPC debugging under a mount option

ENOSPC in btrfs is getting to the point where the extra debugging isn't
required.  I've put it under mount -o enospc_debug just in case someone
is having difficult problems.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

3 files changed, 8 insertions, 2 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 72195378bef9..6297701bc19c 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1254,6 +1254,7 @@ struct btrfs_root {
 #define BTRFS_MOUNT_SPACE_CACHE         (1 << 12)
 #define BTRFS_MOUNT_CLEAR_CACHE         (1 << 13)
 #define BTRFS_MOUNT_USER_SUBVOL_RM_ALLOWED (1 << 14)
+#define BTRFS_MOUNT_ENOSPC_DEBUG         (1 << 15)
 
 #define btrfs_clear_opt(o, opt)         ((o) &= ~BTRFS_MOUNT_##opt)
 #define btrfs_set_opt(o, opt)           ((o) |= BTRFS_MOUNT_##opt)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index a7aaa10c5302..d375fc04a065 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -5377,7 +5377,7 @@ again:
                                num_bytes, data, 1);
                 goto again;
         }
-        if (ret == -ENOSPC) {
+        if (ret == -ENOSPC && btrfs_test_opt(root, ENOSPC_DEBUG)) {
                 struct btrfs_space_info *sinfo;
 
                 sinfo = __find_space_info(root->fs_info, data);
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 0209b5fc772c..db0a827252bd 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -155,7 +155,8 @@ enum {
         Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
         Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
         Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
-        Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed, Opt_err,
+        Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
+        Opt_enospc_debug, Opt_err,
 };
 
 static match_table_t tokens = {
@@ -184,6 +185,7 @@ static match_table_t tokens = {
         {Opt_space_cache, "space_cache"},
         {Opt_clear_cache, "clear_cache"},
         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
+        {Opt_enospc_debug, "enospc_debug"},
         {Opt_err, NULL},
 };
 
@@ -358,6 +360,9 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                 case Opt_user_subvol_rm_allowed:
                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
                         break;
+                case Opt_enospc_debug:
+                        btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
+                        break;
                 case Opt_err:
                         printk(KERN_INFO "btrfs: unrecognized mount option "
                                "'%s'\n", p);