LXR linux/include/linux/writeback.h

   1/*
   2 * include/linux/writeback.h.
   3 */
   4#ifndef WRITEBACK_H
   5#define WRITEBACK_H
   6
   7struct backing_dev_info;
   8
   9extern spinlock_t inode_lock;
  10extern struct list_head inode_in_use;
  11extern struct list_head inode_unused;
  12
  13/*
  14 * Yes, writeback.h requires sched.h
  15 * No, sched.h is not included from here.
  16 */
  17static inline int task_is_pdflush(struct task_struct *task)
  18{
  19        return task->flags & PF_FLUSHER;
  20}
  21
  22#define current_is_pdflush()    task_is_pdflush(current)
  23
  24/*
  25 * fs/fs-writeback.c
  26 */
  27enum writeback_sync_modes {
  28        WB_SYNC_NONE,   /* Don't wait on anything */
  29        WB_SYNC_ALL,    /* Wait on every mapping */
  30        WB_SYNC_HOLD,   /* Hold the inode on sb_dirty for sys_sync() */
  31};
  32
  33/*
  34 * A control structure which tells the writeback code what to do.  These are
  35 * always on the stack, and hence need no locking.  They are always initialised
  36 * in a manner such that unspecified fields are set to zero.
  37 */
  38struct writeback_control {
  39        struct backing_dev_info *bdi;   /* If !NULL, only write back this
  40                                           queue */
  41        enum writeback_sync_modes sync_mode;
  42        unsigned long *older_than_this; /* If !NULL, only write back inodes
  43                                           older than this */
  44        long nr_to_write;               /* Write this many pages, and decrement
  45                                           this for each page written */
  46        long pages_skipped;             /* Pages which were not written */
  47
  48        /*
  49         * For a_ops->writepages(): is start or end are non-zero then this is
  50         * a hint that the filesystem need only write out the pages inside that
  51         * byterange.  The byte at `end' is included in the writeout request.
  52         */
  53        loff_t range_start;
  54        loff_t range_end;
  55
  56        unsigned nonblocking:1;         /* Don't get stuck on request queues */
  57        unsigned encountered_congestion:1; /* An output: a queue is full */
  58        unsigned for_kupdate:1;         /* A kupdate writeback */
  59        unsigned for_reclaim:1;         /* Invoked from the page allocator */
  60        unsigned for_writepages:1;      /* This is a writepages() call */
  61        unsigned range_cyclic:1;        /* range_start is cyclic */
  62};
  63
  64/*
  65 * fs/fs-writeback.c
  66 */     
  67void writeback_inodes(struct writeback_control *wbc);
  68void wake_up_inode(struct inode *inode);
  69int inode_wait(void *);
  70void sync_inodes_sb(struct super_block *, int wait);
  71void sync_inodes(int wait);
  72
  73/* writeback.h requires fs.h; it, too, is not included from here. */
  74static inline void wait_on_inode(struct inode *inode)
  75{
  76        might_sleep();
  77        wait_on_bit(&inode->i_state, __I_LOCK, inode_wait,
  78                                                        TASK_UNINTERRUPTIBLE);
  79}
  80
  81/*
  82 * mm/page-writeback.c
  83 */
  84int wakeup_pdflush(long nr_pages);
  85void laptop_io_completion(void);
  86void laptop_sync_completion(void);
  87void throttle_vm_writeout(void);
  88
  89/* These are exported to sysctl. */
  90extern int dirty_background_ratio;
  91extern int vm_dirty_ratio;
  92extern int dirty_writeback_interval;
  93extern int dirty_expire_interval;
  94extern int block_dump;
  95extern int laptop_mode;
  96
  97struct ctl_table;
  98struct file;
  99int dirty_writeback_centisecs_handler(struct ctl_table *, int, struct file *,
 100                                      void __user *, size_t *, loff_t *);
 101
 102void page_writeback_init(void);
 103void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
 104                                        unsigned long nr_pages_dirtied);
 105
 106static inline void
 107balance_dirty_pages_ratelimited(struct address_space *mapping)
 108{
 109        balance_dirty_pages_ratelimited_nr(mapping, 1);
 110}
 111
 112int pdflush_operation(void (*fn)(unsigned long), unsigned long arg0);
 113int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
 114int sync_page_range(struct inode *inode, struct address_space *mapping,
 115                        loff_t pos, loff_t count);
 116int sync_page_range_nolock(struct inode *inode, struct address_space *mapping,
 117                           loff_t pos, loff_t count);
 118
 119/* pdflush.c */
 120extern int nr_pdflush_threads;  /* Global so it can be exported to sysctl
 121                                   read-only. */
 122
 123
 124#endif          /* WRITEBACK_H */
 125