ext4: no need to generate from free list in mballoc

commit ebf6cb7c6e1241984f75f29f1bdbfa2fe7168f88 upstream.

Commit 7a2fcbf7f85 ("ext4: don't use blocks freed but not yet committed in
buddy cache init") added a code to mark as used blocks in the list of not yet
committed freed blocks during initialization of a buddy page. However
ext4_mb_free_metadata() makes sure buddy page is already loaded and takes a
reference to it so it cannot happen that ext4_mb_init_cache() is called
when efd list is non-empty. Just remove the
ext4_mb_generate_from_freelist() call.

Fixes: 7a2fcbf7f85('ext4: don't use blocks freed but not yet committed in buddy cache init')
Signed-off-by: Wang Jianjian <wangjianjian0@foxmail.com>
Link: https://lore.kernel.org/r/tencent_53CBCB1668358AE862684E453DF37B722008@qq.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 1e59930..a7b8558 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -417,8 +417,6 @@ static const char * const ext4_groupinfo_slab_names[NR_GRPINFO_CACHES] = {
 
 static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
                                        ext4_group_t group);
-static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
-                                               ext4_group_t group);
 static void ext4_mb_new_preallocation(struct ext4_allocation_context *ac);
 
 static bool ext4_mb_good_group(struct ext4_allocation_context *ac,
@@ -1361,17 +1359,17 @@ static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
                 * We place the buddy block and bitmap block
                 * close together
                 */
+               grinfo = ext4_get_group_info(sb, group);
+               if (!grinfo) {
+                       err = -EFSCORRUPTED;
+                       goto out;
+               }
                if ((first_block + i) & 1) {
                        /* this is block of buddy */
                        BUG_ON(incore == NULL);
                        mb_debug(sb, "put buddy for group %u in page %lu/%x\n",
                                group, page->index, i * blocksize);
                        trace_ext4_mb_buddy_bitmap_load(sb, group);
-                       grinfo = ext4_get_group_info(sb, group);
-                       if (!grinfo) {
-                               err = -EFSCORRUPTED;
-                               goto out;
-                       }
                        grinfo->bb_fragments = 0;
                        memset(grinfo->bb_counters, 0,
                               sizeof(*grinfo->bb_counters) *
@@ -1398,7 +1396,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
 
                        /* mark all preallocated blks used in in-core bitmap */
                        ext4_mb_generate_from_pa(sb, data, group);
-                       ext4_mb_generate_from_freelist(sb, data, group);
+                       WARN_ON_ONCE(!RB_EMPTY_ROOT(&grinfo->bb_free_root));
                        ext4_unlock_group(sb, group);
 
                        /* set incore so that the buddy information can be
@@ -4959,31 +4957,6 @@ try_group_pa:
 }
 
 /*
- * the function goes through all block freed in the group
- * but not yet committed and marks them used in in-core bitmap.
- * buddy must be generated from this bitmap
- * Need to be called with the ext4 group lock held
- */
-static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
-                                               ext4_group_t group)
-{
-       struct rb_node *n;
-       struct ext4_group_info *grp;
-       struct ext4_free_data *entry;
-
-       grp = ext4_get_group_info(sb, group);
-       if (!grp)
-               return;
-       n = rb_first(&(grp->bb_free_root));
-
-       while (n) {
-               entry = rb_entry(n, struct ext4_free_data, efd_node);
-               mb_set_bits(bitmap, entry->efd_start_cluster, entry->efd_count);
-               n = rb_next(n);
-       }
-}
-
-/*
  * the function goes through all preallocation in this group and marks them
  * used in in-core bitmap. buddy must be generated from this bitmap
  * Need to be called with ext4 group lock held