-/*
- * Call the ->sync_fs super_op against all filesytems which are r/w and
- * which implement it.
- *
- * This operation is careful to avoid the livelock which could easily happen
- * if two or more filesystems are being continuously dirtied. s_need_sync_fs
- * is used only here. We set it against all filesystems and then clear it as
- * we sync them. So redirtied filesystems are skipped.
- *
- * But if process A is currently running sync_filesytems and then process B
- * calls sync_filesystems as well, process B will set all the s_need_sync_fs
- * flags again, which will cause process A to resync everything. Fix that with
- * a local mutex.
- *
- * (Fabian) Avoid sync_fs with clean fs & wait mode 0
- */
-void sync_filesystems(int wait)
-{
- struct super_block *sb;
- static DECLARE_MUTEX(mutex);
-
- down(&mutex); /* Could be down_interruptible */
- spin_lock(&sb_lock);
- list_for_each_entry(sb, &super_blocks, s_list) {
- if (!sb->s_op->sync_fs)
- continue;
- if (sb->s_flags & MS_RDONLY)
- continue;
- sb->s_need_sync_fs = 1;
- }
-
-restart:
- list_for_each_entry(sb, &super_blocks, s_list) {
- if (!sb->s_need_sync_fs)
- continue;
- sb->s_need_sync_fs = 0;
- if (sb->s_flags & MS_RDONLY)
- continue; /* hm. Was remounted r/o meanwhile */
- sb->s_count++;
- spin_unlock(&sb_lock);
- down_read(&sb->s_umount);
- if (sb->s_root && (wait || sb->s_dirt))
- sb->s_op->sync_fs(sb, wait);
- up_read(&sb->s_umount);
- /* restart only when sb is no longer on the list */
- spin_lock(&sb_lock);
- if (__put_super_and_need_restart(sb))
- goto restart;
- }
- spin_unlock(&sb_lock);
- up(&mutex);
-}
-