From e5004753388dcf5e1b8a52ac0ab807d232340fbb Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 5 May 2009 16:08:56 +0200 Subject: cleanup sync_supers Merge the write_super helper into sync_super and move the check for ->write_super earlier so that we can avoid grabbing a reference to a superblock that doesn't have it. While we're at it also add a little comment documenting sync_supers. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro --- fs/super.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) (limited to 'fs/super.c') diff --git a/fs/super.c b/fs/super.c index d9a29d5b1d2..cb19fffc768 100644 --- a/fs/super.c +++ b/fs/super.c @@ -399,16 +399,14 @@ void drop_super(struct super_block *sb) EXPORT_SYMBOL(drop_super); -static inline void write_super(struct super_block *sb) -{ - lock_super(sb); - if (sb->s_root && sb->s_dirt) - if (sb->s_op->write_super) - sb->s_op->write_super(sb); - unlock_super(sb); -} - -/* +/** + * sync_supers - helper for periodic superblock writeback + * + * Call the write_super method if present on all dirty superblocks in + * the system. This is for the periodic writeback used by most older + * filesystems. For data integrity superblock writeback use + * sync_filesystems() instead. + * * Note: check the dirty flag before waiting, so we don't * hold up the sync while mounting a device. (The newly * mounted device won't need syncing.) @@ -420,12 +418,17 @@ void sync_supers(void) spin_lock(&sb_lock); restart: list_for_each_entry(sb, &super_blocks, s_list) { - if (sb->s_dirt) { + if (sb->s_op->write_super && sb->s_dirt) { sb->s_count++; spin_unlock(&sb_lock); + down_read(&sb->s_umount); - write_super(sb); + lock_super(sb); + if (sb->s_root && sb->s_dirt) + sb->s_op->write_super(sb); + unlock_super(sb); up_read(&sb->s_umount); + spin_lock(&sb_lock); if (__put_super_and_need_restart(sb)) goto restart; -- cgit v1.2.3