ext4: initialize the percpu counters before replaying the journal
authorTheodore Ts'o <tytso@mit.edu>
Wed, 3 Nov 2010 16:03:21 +0000 (12:03 -0400)
committerTheodore Ts'o <tytso@mit.edu>
Wed, 3 Nov 2010 16:03:21 +0000 (12:03 -0400)
We now initialize the percpu counters before replaying the journal,
but after the journal, we recalculate the global counters, to deal
with the possibility of the per-blockgroup counts getting updated by
the journal replay.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
fs/ext4/super.c

index 4d7ef31eacb1e47d11dc51409cb5a02d275a7f70..04352e9729d0d3c9f32fd04434706ce4d22c95e4 100644 (file)
@@ -3347,6 +3347,24 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
        get_random_bytes(&sbi->s_next_generation, sizeof(u32));
        spin_lock_init(&sbi->s_next_gen_lock);
 
+       err = percpu_counter_init(&sbi->s_freeblocks_counter,
+                       ext4_count_free_blocks(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_dirtyblocks_counter, 0);
+       }
+       if (err) {
+               ext4_msg(sb, KERN_ERR, "insufficient memory");
+               goto failed_mount3;
+       }
+
        sbi->s_stripe = ext4_get_stripe_size(sbi);
        sbi->s_max_writeback_mb_bump = 128;
 
@@ -3445,22 +3463,19 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
        }
        set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
 
-no_journal:
-       err = percpu_counter_init(&sbi->s_freeblocks_counter,
-                                 ext4_count_free_blocks(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_dirtyblocks_counter, 0);
-       if (err) {
-               ext4_msg(sb, KERN_ERR, "insufficient memory");
-               goto failed_mount_wq;
-       }
+       /*
+        * The journal may have updated the bg summary counts, so we
+        * need to update the global counters.
+        */
+       percpu_counter_set(&sbi->s_freeblocks_counter,
+                          ext4_count_free_blocks(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_dirtyblocks_counter, 0);
 
+no_journal:
        EXT4_SB(sb)->dio_unwritten_wq = create_workqueue("ext4-dio-unwritten");
        if (!EXT4_SB(sb)->dio_unwritten_wq) {
                printk(KERN_ERR "EXT4-fs: failed to create DIO workqueue\n");
@@ -3610,10 +3625,6 @@ failed_mount_wq:
                jbd2_journal_destroy(sbi->s_journal);
                sbi->s_journal = NULL;
        }
-       percpu_counter_destroy(&sbi->s_freeblocks_counter);
-       percpu_counter_destroy(&sbi->s_freeinodes_counter);
-       percpu_counter_destroy(&sbi->s_dirs_counter);
-       percpu_counter_destroy(&sbi->s_dirtyblocks_counter);
 failed_mount3:
        if (sbi->s_flex_groups) {
                if (is_vmalloc_addr(sbi->s_flex_groups))
@@ -3621,6 +3632,10 @@ failed_mount3:
                else
                        kfree(sbi->s_flex_groups);
        }
+       percpu_counter_destroy(&sbi->s_freeblocks_counter);
+       percpu_counter_destroy(&sbi->s_freeinodes_counter);
+       percpu_counter_destroy(&sbi->s_dirs_counter);
+       percpu_counter_destroy(&sbi->s_dirtyblocks_counter);
 failed_mount2:
        for (i = 0; i < db_count; i++)
                brelse(sbi->s_group_desc[i]);
@@ -3948,13 +3963,11 @@ 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);
-       if (percpu_counter_initialized(&EXT4_SB(sb)->s_freeblocks_counter))
-               ext4_free_blocks_count_set(es, percpu_counter_sum_positive(
-                                       &EXT4_SB(sb)->s_freeblocks_counter));
-       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));
+       ext4_free_blocks_count_set(es, percpu_counter_sum_positive(
+                                          &EXT4_SB(sb)->s_freeblocks_counter));
+       es->s_free_inodes_count =
+               cpu_to_le32(percpu_counter_sum_positive(
+                               &EXT4_SB(sb)->s_freeinodes_counter));
        sb->s_dirt = 0;
        BUFFER_TRACE(sbh, "marking dirty");
        mark_buffer_dirty(sbh);