linux-kernel - [PATCH 1/7] affs: remove strange argument of affs_commit

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Date:	Tue,  5 Jun 2012 14:28:09 +0300
From:	Artem Bityutskiy <dedekind1@...il.com>
To:	Al Viro <viro@...IV.linux.org.uk>
Cc:	Linux FS Maling List <linux-fsdevel@...r.kernel.org>,
	Linux Kernel Maling List <linux-kernel@...r.kernel.org>
Subject: [PATCH 1/7] affs: remove strange argument of affs_commit_super

From: Artem Bityutskiy <artem.bityutskiy@...ux.intel.com>

The 'affs_commit_super()' function takes a 'clean' argument which it stores in
the 'bm_flags' field of the AFFS root block. This patch removes it to make the
code simpler and cleaner and enable few other clean-ups.

Currently AFFS stores values '1' and '2' in 'bm_flags', and I fail to see any
logic when it prefers one or another. AFFS writes '1' only from
'->put_super()', while '->sync_fs()' and '->write_super()' store value '2'.
So on the first glance, it looks like we want to have '1' if we unmount.
However, this does not really happen in these cases:
  1. superblock is written via 'write_super()' then we unmount;
  2. we re-mount R/O, then unmount.
which are quite typical.

I could not find good documentation describing this field, except of one random
piece of documentation in the internet which says that -1 means that the root
block is valid, which is not consistent with what we have in the Linux AFFS
driver.

Thus, my conclusion is that value of '1' is as good as value of '2' and we can
just always use '2'. This is exactly what this patch does.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@...ux.intel.com>
---
 fs/affs/super.c |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/affs/super.c b/fs/affs/super.c
index 0782653..698282a 100644
--- a/fs/affs/super.c
+++ b/fs/affs/super.c
@@ -25,13 +25,13 @@ static int affs_statfs(struct dentry *dentry, struct kstatfs *buf);
 static int affs_remount (struct super_block *sb, int *flags, char *data);

 static void
-affs_commit_super(struct super_block *sb, int wait, int clean)
+affs_commit_super(struct super_block *sb, int wait)
 {
 	struct affs_sb_info *sbi = AFFS_SB(sb);
 	struct buffer_head *bh = sbi->s_root_bh;
 	struct affs_root_tail *tail = AFFS_ROOT_TAIL(sb, bh);

-	tail->bm_flag = cpu_to_be32(clean);
+	tail->bm_flag = cpu_to_be32(2);
 	secs_to_datestamp(get_seconds(), &tail->disk_change);
 	affs_fix_checksum(sb, bh);
 	mark_buffer_dirty(bh);
@@ -46,7 +46,7 @@ affs_put_super(struct super_block *sb)
 	pr_debug("AFFS: put_super()\n");

 	if (!(sb->s_flags & MS_RDONLY) && sb->s_dirt)
-		affs_commit_super(sb, 1, 1);
+		affs_commit_super(sb, 1);

 	kfree(sbi->s_prefix);
 	affs_free_bitmap(sb);
@@ -60,7 +60,7 @@ affs_write_super(struct super_block *sb)
 {
 	lock_super(sb);
 	if (!(sb->s_flags & MS_RDONLY))
-		affs_commit_super(sb, 1, 2);
+		affs_commit_super(sb, 1);
 	sb->s_dirt = 0;
 	unlock_super(sb);

@@ -71,7 +71,7 @@ static int
 affs_sync_fs(struct super_block *sb, int wait)
 {
 	lock_super(sb);
-	affs_commit_super(sb, wait, 2);
+	affs_commit_super(sb, wait);
 	sb->s_dirt = 0;
 	unlock_super(sb);
 	return 0;
-- 
1.7.7.6

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