fs/reiser4/entd.h

   1 /* Copyright 2003 by Hans Reiser, licensing governed by reiser4/README */
   2
   3 /* Ent daemon. */
   4
   5 #ifndef __ENTD_H__
   6 #define __ENTD_H__
   7
   8 #include "context.h"
   9
  10 #include <linux/fs.h>
  11 #include <linux/completion.h>
  12 #include <linux/wait.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/sched.h>        /* for struct task_struct */
  15
  16 #define WBQ_MAGIC 0x7876dc76
  17
  18 /* write-back request. */
  19 struct wbq {
  20         int magic;
  21         struct list_head link; /* list head of this list is in entd context */
  22         struct writeback_control *wbc;
  23         struct page *page;
  24         struct address_space *mapping;
  25         struct completion completion;
  26         jnode *node; /* set if ent thread captured requested page */
  27         int written; /* set if ent thread wrote requested page */
  28 };
  29
  30 /* ent-thread context. This is used to synchronize starting/stopping ent
  31  * threads. */
  32 typedef struct entd_context {
  33          /* wait queue that ent thread waits on for more work. It's
  34           * signaled by write_page_by_ent(). */
  35         wait_queue_head_t wait;
  36         /* spinlock protecting other fields */
  37         spinlock_t guard;
  38         /* ent thread */
  39         struct task_struct *tsk;
  40         /* set to indicate that ent thread should leave. */
  41         int done;
  42         /* counter of active flushers */
  43         int flushers;
  44         /*
  45          * when reiser4_writepage asks entd to write a page - it adds struct
  46          * wbq to this list
  47          */
  48         struct list_head todo_list;
  49         /* number of elements on the above list */
  50         int nr_todo_reqs;
  51
  52         struct wbq *cur_request;
  53         /*
  54          * when entd writes a page it moves write-back request from todo_list
  55          * to done_list. This list is used at the end of entd iteration to
  56          * wakeup requestors and iput inodes.
  57          */
  58         struct list_head done_list;
  59         /* number of elements on the above list */
  60         int nr_done_reqs;
  61
  62 #if REISER4_DEBUG
  63         /* list of all active flushers */
  64         struct list_head flushers_list;
  65 #endif
  66 } entd_context;
  67
  68 extern int  reiser4_init_entd(struct super_block *);
  69 extern void reiser4_done_entd(struct super_block *);
  70
  71 extern void reiser4_enter_flush(struct super_block *);
  72 extern void reiser4_leave_flush(struct super_block *);
  73
  74 extern int write_page_by_ent(struct page *, struct writeback_control *);
  75 extern int wbq_available(void);
  76 extern void ent_writes_page(struct super_block *, struct page *);
  77
  78 extern jnode *get_jnode_by_wbq(struct super_block *, struct wbq *);
  79 /* __ENTD_H__ */
  80 #endif
  81
  82 /* Make Linus happy.
  83    Local variables:
  84    c-indentation-style: "K&R"
  85    mode-name: "LC"
  86    c-basic-offset: 8
  87    tab-width: 8
  88    fill-column: 120
  89    End:
  90 */