btrfs: factor sysfs code out of link_block_group

The part of link_block_group that just creates the sysfs object is
independent and can be factored out to a helper.

Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 3348f9a..37e56b0 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4,7 +4,6 @@
  */
 
 #include <linux/sched.h>
-#include <linux/sched/mm.h>
 #include <linux/sched/signal.h>
 #include <linux/pagemap.h>
 #include <linux/writeback.h>
@@ -7573,7 +7572,6 @@ int btrfs_free_block_groups(struct btrfs_fs_info *info)
 static void link_block_group(struct btrfs_block_group_cache *cache)
 {
        struct btrfs_space_info *space_info = cache->space_info;
-       struct btrfs_fs_info *fs_info = cache->fs_info;
        int index = btrfs_bg_flags_to_raid_index(cache->flags);
        bool first = false;
 
@@ -7583,39 +7581,8 @@ static void link_block_group(struct btrfs_block_group_cache *cache)
        list_add_tail(&cache->list, &space_info->block_groups[index]);
        up_write(&space_info->groups_sem);
 
-       if (first) {
-               struct raid_kobject *rkobj;
-               unsigned int nofs_flag;
-               int ret;
-
-               /*
-                * Setup a NOFS context because kobject_add(), deep in its call
-                * chain, does GFP_KERNEL allocations, and we are often called
-                * in a context where if reclaim is triggered we can deadlock
-                * (we are either holding a transaction handle or some lock
-                * required for a transaction commit).
-                */
-               nofs_flag = memalloc_nofs_save();
-               rkobj = kzalloc(sizeof(*rkobj), GFP_KERNEL);
-               if (!rkobj) {
-                       memalloc_nofs_restore(nofs_flag);
-                       btrfs_warn(cache->fs_info,
-                               "couldn't alloc memory for raid level kobject");
-                       return;
-               }
-               rkobj->flags = cache->flags;
-               kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
-               ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s",
-                                 btrfs_bg_type_to_raid_name(rkobj->flags));
-               memalloc_nofs_restore(nofs_flag);
-               if (ret) {
-                       kobject_put(&rkobj->kobj);
-                       btrfs_warn(fs_info,
-                          "failed to add kobject for block cache, ignoring");
-                       return;
-               }
-               space_info->block_group_kobjs[index] = &rkobj->kobj;
-       }
+       if (first)
+               btrfs_sysfs_add_block_group_type(cache);
 }
 
 static struct btrfs_block_group_cache *

diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 115499c..50cb9f9 100644 (file)
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -4,6 +4,7 @@
  */
 
 #include <linux/sched.h>
+#include <linux/sched/mm.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/completion.h>
@@ -749,6 +750,51 @@ static void init_feature_attrs(void)
        }
 }
 
+/*
+ * Create a sysfs entry for a given block group type at path
+ * /sys/fs/btrfs/UUID/allocation/data/TYPE
+ */
+void btrfs_sysfs_add_block_group_type(struct btrfs_block_group_cache *cache)
+{
+       struct btrfs_fs_info *fs_info = cache->fs_info;
+       struct btrfs_space_info *space_info = cache->space_info;
+       struct raid_kobject *rkobj;
+       const int index = btrfs_bg_flags_to_raid_index(cache->flags);
+       unsigned int nofs_flag;
+       int ret;
+
+       /*
+        * Setup a NOFS context because kobject_add(), deep in its call chain,
+        * does GFP_KERNEL allocations, and we are often called in a context
+        * where if reclaim is triggered we can deadlock (we are either holding
+        * a transaction handle or some lock required for a transaction
+        * commit).
+        */
+       nofs_flag = memalloc_nofs_save();
+
+       rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
+       if (!rkobj) {
+               memalloc_nofs_restore(nofs_flag);
+               btrfs_warn(cache->fs_info,
+                               "couldn't alloc memory for raid level kobject");
+               return;
+       }
+
+       rkobj->flags = cache->flags;
+       kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
+       ret = kobject_add(&rkobj->kobj, &space_info->kobj, "%s",
+                         btrfs_bg_type_to_raid_name(rkobj->flags));
+       memalloc_nofs_restore(nofs_flag);
+       if (ret) {
+               kobject_put(&rkobj->kobj);
+               btrfs_warn(fs_info,
+                       "failed to add kobject for block cache, ignoring");
+               return;
+       }
+
+       space_info->block_group_kobjs[index] = &rkobj->kobj;
+}
+
 /* when one_device is NULL, it removes all device links */
 
 int btrfs_sysfs_rm_device_link(struct btrfs_fs_devices *fs_devices,

diff --git a/fs/btrfs/sysfs.h b/fs/btrfs/sysfs.h
index 4f62298..403240e 100644 (file)
--- a/fs/btrfs/sysfs.h
+++ b/fs/btrfs/sysfs.h
@@ -96,5 +96,6 @@ int __init btrfs_init_sysfs(void);
 void __cold btrfs_exit_sysfs(void);
 int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info);
 void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info);
+void btrfs_sysfs_add_block_group_type(struct btrfs_block_group_cache *cache);
 
 #endif