linux-ext4 - [PATCH 3/5] ext4: ext4_mark_recovery_complete() doesn't need to use lock

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Message-Id: <1240717765-16572-4-git-send-email-tytso@mit.edu>
Date:	Sat, 25 Apr 2009 23:49:23 -0400
From:	Theodore Ts'o <tytso@....edu>
To:	Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc:	Linux Kernel Developers List <linux-kernel@...r.kernel.org>,
	Christoph Hellwig <hch@...radead.org>,
	Al Viro <viro@...IV.linux.org.uk>,
	Theodore Ts'o <tytso@....edu>
Subject: [PATCH 3/5] ext4: ext4_mark_recovery_complete() doesn't need to use lock_super

The function ext4_mark_recovery_complete() is called from two call
paths: either (a) while mounting the filesystem, in which case there's
no danger of any other CPU calling write_super() until the mount is
completed, and (b) while remounting the filesystem read-write, in
which case the fs core has already locked the superblock, and in any
case write_super() wouldn't be called until the filesystem is
successfully changed from being mounted read-only to read-write.

Signed-off-by: "Theodore Ts'o" <tytso@....edu>
---
 fs/ext4/super.c |   11 +----------
 1 files changed, 1 insertions(+), 10 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index e0b0c9f..176d43f 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3198,14 +3198,12 @@ static void ext4_mark_recovery_complete(struct super_block *sb,
 	if (jbd2_journal_flush(journal) < 0)
 		goto out;
 
-	lock_super(sb);
 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER) &&
 	    sb->s_flags & MS_RDONLY) {
 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
 		sb->s_dirt = 0;
 		ext4_commit_super(sb, es, 1);
 	}
-	unlock_super(sb);
 
 out:
 	jbd2_journal_unlock_updates(journal);
@@ -3438,15 +3436,8 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
 			    (sbi->s_mount_state & EXT4_VALID_FS))
 				es->s_state = cpu_to_le16(sbi->s_mount_state);
 
-			/*
-			 * We have to unlock super so that we can wait for
-			 * transactions.
-			 */
-			if (sbi->s_journal) {
-				unlock_super(sb);
+			if (sbi->s_journal)
 				ext4_mark_recovery_complete(sb, es);
-				lock_super(sb);
-			}
 		} else {
 			int ret;
 			if ((ret = EXT4_HAS_RO_COMPAT_FEATURE(sb,
-- 
1.5.6.3

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