[PATCH 2/2] AFFS: wait for sb synchronization when needed

From: Artem Bityutskiy
Date: Fri Jun 11 2010 - 11:09:28 EST


From: Artem Bityutskiy <Artem.Bityutskiy@xxxxxxxxx>

AFFS does not ever wait for superblock synchronization in
->put_super(), ->write_super, and ->sync_fs().

However, it should wait for synchronization in ->put_super() because
it is about to be unmounted, in ->write_super() because this is
periodic SB synchronization performed from a separate kernel thread,
and in ->sync_fs() it should respect the 'wait' flag. This patch fixes
the situation.

Also, in ->put_super(), do not write the SB if it is not dirty.

Tested-by: Artem Bityutskiy <Artem.Bityutskiy@xxxxxxxxx>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@xxxxxxxxx>
---
fs/affs/super.c | 12 +++++++-----
1 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/fs/affs/super.c b/fs/affs/super.c
index 8447451..9f6fbee 100644
--- a/fs/affs/super.c
+++ b/fs/affs/super.c
@@ -26,7 +26,7 @@ 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 clean)
+affs_commit_super(struct super_block *sb, int wait, int clean)
{
struct affs_sb_info *sbi = AFFS_SB(sb);
struct buffer_head *bh = sbi->s_root_bh;
@@ -36,6 +36,8 @@ affs_commit_super(struct super_block *sb, int clean)
secs_to_datestamp(get_seconds(), &tail->disk_change);
affs_fix_checksum(sb, bh);
mark_buffer_dirty(bh);
+ if (wait)
+ sync_dirty_buffer(bh);
}

static void
@@ -46,8 +48,8 @@ affs_put_super(struct super_block *sb)

lock_kernel();

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

kfree(sbi->s_prefix);
affs_free_bitmap(sb);
@@ -63,7 +65,7 @@ affs_write_super(struct super_block *sb)
{
lock_super(sb);
if (!(sb->s_flags & MS_RDONLY))
- affs_commit_super(sb, 2);
+ affs_commit_super(sb, 1, 2);
sb->s_dirt = 0;
unlock_super(sb);

@@ -74,7 +76,7 @@ static int
affs_sync_fs(struct super_block *sb, int wait)
{
lock_super(sb);
- affs_commit_super(sb, 2);
+ affs_commit_super(sb, wait, 2);
sb->s_dirt = 0;
unlock_super(sb);
return 0;
--
1.7.0.1

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