ext4: rearrange initialization to fix EXT4FS_DEBUG

The EXT4FS_DEBUG is a *very* developer specific #ifdef designed for
ext4 developers only.  (You have to modify fs/ext4/ext4.h to enable
it.)

Rearrange how we initialize data structures to avoid calling
ext4_count_free_clusters() until the multiblock allocator has been
initialized.

This also allows us to only call ext4_count_free_clusters() once, and
simplifies the code somewhat.

(Thanks to Chen Gang <gang.chen.5i5j@gmail.com> for pointing out a
!CONFIG_SMP compile breakage in the original patch.)

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 6df7bc6..32b43ad 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2142,10 +2142,6 @@ static int ext4_check_descriptors(struct super_block *sb,
        }
        if (NULL != first_not_zeroed)
                *first_not_zeroed = grp;
-
-       ext4_free_blocks_count_set(sbi->s_es,
-                                  EXT4_C2B(sbi, ext4_count_free_clusters(sb)));
-       sbi->s_es->s_free_inodes_count =cpu_to_le32(ext4_count_free_inodes(sb));
        return 1;
 }
 
@@ -3883,13 +3879,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
                ext4_msg(sb, KERN_ERR, "group descriptors corrupted!");
                goto failed_mount2;
        }
-       if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
-               if (!ext4_fill_flex_info(sb)) {
-                       ext4_msg(sb, KERN_ERR,
-                              "unable to initialize "
-                              "flex_bg meta info!");
-                       goto failed_mount2;
-               }
 
        sbi->s_gdb_count = db_count;
        get_random_bytes(&sbi->s_next_generation, sizeof(u32));
@@ -3902,23 +3891,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
        /* Register extent status tree shrinker */
        ext4_es_register_shrinker(sbi);
 
-       err = percpu_counter_init(&sbi->s_freeclusters_counter,
-                       ext4_count_free_clusters(sb));
-       if (!err) {
-               err = percpu_counter_init(&sbi->s_freeinodes_counter,
-                               ext4_count_free_inodes(sb));
-       }
-       if (!err) {
-               err = percpu_counter_init(&sbi->s_dirs_counter,
-                               ext4_count_dirs(sb));
-       }
-       if (!err) {
-               err = percpu_counter_init(&sbi->s_dirtyclusters_counter, 0);
-       }
-       if (!err) {
-               err = percpu_counter_init(&sbi->s_extent_cache_cnt, 0);
-       }
-       if (err) {
+       if ((err = percpu_counter_init(&sbi->s_extent_cache_cnt, 0)) != 0) {
                ext4_msg(sb, KERN_ERR, "insufficient memory");
                goto failed_mount3;
        }
@@ -4022,18 +3995,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 
        sbi->s_journal->j_commit_callback = ext4_journal_commit_callback;
 
-       /*
-        * The journal may have updated the bg summary counts, so we
-        * need to update the global counters.
-        */
-       percpu_counter_set(&sbi->s_freeclusters_counter,
-                          ext4_count_free_clusters(sb));
-       percpu_counter_set(&sbi->s_freeinodes_counter,
-                          ext4_count_free_inodes(sb));
-       percpu_counter_set(&sbi->s_dirs_counter,
-                          ext4_count_dirs(sb));
-       percpu_counter_set(&sbi->s_dirtyclusters_counter, 0);
-
 no_journal:
        if (ext4_mballoc_ready) {
                sbi->s_mb_cache = ext4_xattr_create_cache(sb->s_id);
@@ -4141,6 +4102,33 @@ no_journal:
                goto failed_mount5;
        }
 
+       block = ext4_count_free_clusters(sb);
+       ext4_free_blocks_count_set(sbi->s_es, 
+                                  EXT4_C2B(sbi, block));
+       err = percpu_counter_init(&sbi->s_freeclusters_counter, block);
+       if (!err) {
+               unsigned long freei = ext4_count_free_inodes(sb);
+               sbi->s_es->s_free_inodes_count = cpu_to_le32(freei);
+               err = percpu_counter_init(&sbi->s_freeinodes_counter, freei);
+       }
+       if (!err)
+               err = percpu_counter_init(&sbi->s_dirs_counter,
+                                         ext4_count_dirs(sb));
+       if (!err)
+               err = percpu_counter_init(&sbi->s_dirtyclusters_counter, 0);
+       if (err) {
+               ext4_msg(sb, KERN_ERR, "insufficient memory");
+               goto failed_mount6;
+       }
+
+       if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
+               if (!ext4_fill_flex_info(sb)) {
+                       ext4_msg(sb, KERN_ERR,
+                              "unable to initialize "
+                              "flex_bg meta info!");
+                       goto failed_mount6;
+               }
+
        err = ext4_register_li_request(sb, first_not_zeroed);
        if (err)
                goto failed_mount6;
@@ -4215,6 +4203,12 @@ failed_mount7:
        ext4_unregister_li_request(sb);
 failed_mount6:
        ext4_mb_release(sb);
+       if (sbi->s_flex_groups)
+               ext4_kvfree(sbi->s_flex_groups);
+       percpu_counter_destroy(&sbi->s_freeclusters_counter);
+       percpu_counter_destroy(&sbi->s_freeinodes_counter);
+       percpu_counter_destroy(&sbi->s_dirs_counter);
+       percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
 failed_mount5:
        ext4_ext_release(sb);
        ext4_release_system_zone(sb);
@@ -4233,12 +4227,6 @@ failed_mount_wq:
 failed_mount3:
        ext4_es_unregister_shrinker(sbi);
        del_timer_sync(&sbi->s_err_report);
-       if (sbi->s_flex_groups)
-               ext4_kvfree(sbi->s_flex_groups);
-       percpu_counter_destroy(&sbi->s_freeclusters_counter);
-       percpu_counter_destroy(&sbi->s_freeinodes_counter);
-       percpu_counter_destroy(&sbi->s_dirs_counter);
-       percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
        percpu_counter_destroy(&sbi->s_extent_cache_cnt);
        if (sbi->s_mmp_tsk)
                kthread_stop(sbi->s_mmp_tsk);
@@ -4556,11 +4544,13 @@ static int ext4_commit_super(struct super_block *sb, int sync)
        else
                es->s_kbytes_written =
                        cpu_to_le64(EXT4_SB(sb)->s_kbytes_written);
-       ext4_free_blocks_count_set(es,
+       if (percpu_counter_initialized(&EXT4_SB(sb)->s_freeclusters_counter))
+               ext4_free_blocks_count_set(es,
                        EXT4_C2B(EXT4_SB(sb), percpu_counter_sum_positive(
                                &EXT4_SB(sb)->s_freeclusters_counter)));
-       es->s_free_inodes_count =
-               cpu_to_le32(percpu_counter_sum_positive(
+       if (percpu_counter_initialized(&EXT4_SB(sb)->s_freeinodes_counter))
+               es->s_free_inodes_count =
+                       cpu_to_le32(percpu_counter_sum_positive(
                                &EXT4_SB(sb)->s_freeinodes_counter));
        BUFFER_TRACE(sbh, "marking dirty");
        ext4_superblock_csum_set(sb);