From ce7e010aef63dc6b37a2354f7c9f5f4aedb37978 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Wed, 3 Nov 2010 12:03:21 -0400
Subject: ext4: initialize the percpu counters before replaying the journal

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 | 65 ++++++++++++++++++++++++++++++++++-----------------------
 1 file changed, 39 insertions(+), 26 deletions(-)

(limited to 'fs/ext4')

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 4d7ef31eacb..04352e9729d 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -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);
-- 
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