From: Theodore Ts'o <tytso@mit.edu>
Date: Wed, 3 Nov 2010 16:03:21 +0000 (-0400)
Subject: ext4: initialize the percpu counters before replaying the journal
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=ce7e010aef63dc6b37a2354f7c9f5f4aedb37978;p=deliverable%2Flinux.git

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>
---

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 4d7ef31eacb1..04352e9729d0 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);