1 /* 2 * include/linux/writeback.h 3 */ 4 #ifndef WRITEBACK_H 5 #define WRITEBACK_H 6 7 #include <linux/sched.h> 8 9 struct backing_dev_info; 10 11 extern spinlock_t inode_lock; 12 extern struct list_head inode_in_use; 13 extern struct list_head inode_unused; 14 15 /* 16 * Yes, writeback.h requires sched.h 17 * No, sched.h is not included from here. 18 */ 19 static inline int task_is_pdflush(struct task_struct *task) 20 { 21 return task->flags & PF_FLUSHER; 22 } 23 24 #define current_is_pdflush() task_is_pdflush(current) 25 26 /* 27 * fs/fs-writeback.c 28 */ 29 enum writeback_sync_modes { 30 WB_SYNC_NONE, /* Don't wait on anything */ 31 WB_SYNC_ALL, /* Wait on every mapping */ 32 WB_SYNC_HOLD, /* Hold the inode on sb_dirty for sys_sync() */ 33 }; 34 35 /* 36 * A control structure which tells the writeback code what to do. These are 37 * always on the stack, and hence need no locking. They are always initialised 38 * in a manner such that unspecified fields are set to zero. 39 */ 40 struct writeback_control { 41 struct backing_dev_info *bdi; /* If !NULL, only write back this 42 queue */ 43 enum writeback_sync_modes sync_mode; 44 unsigned long *older_than_this; /* If !NULL, only write back inodes 45 older than this */ 46 long nr_to_write; /* Write this many pages, and decrement 47 this for each page written */ 48 long pages_skipped; /* Pages which were not written */ 49 50 /* 51 * For a_ops->writepages(): is start or end are non-zero then this is 52 * a hint that the filesystem need only write out the pages inside that 53 * byterange. The byte at `end' is included in the writeout request. 54 */ 55 loff_t range_start; 56 loff_t range_end; 57 58 unsigned nonblocking:1; /* Don't get stuck on request queues */ 59 unsigned encountered_congestion:1; /* An output: a queue is full */ 60 unsigned for_kupdate:1; /* A kupdate writeback */ 61 unsigned for_reclaim:1; /* Invoked from the page allocator */ 62 unsigned for_writepages:1; /* This is a writepages() call */ 63 unsigned range_cyclic:1; /* range_start is cyclic */ 64 65 void *fs_private; /* For use by ->writepages() */ 66 }; 67 68 /* 69 * fs/fs-writeback.c 70 */ 71 void writeback_inodes(struct writeback_control *wbc); 72 void wake_up_inode(struct inode *inode); 73 int inode_wait(void *); 74 void sync_inodes_sb(struct super_block *, int wait); 75 void sync_inodes(int wait); 76 77 /* writeback.h requires fs.h; it, too, is not included from here. */ 78 static inline void wait_on_inode(struct inode *inode) 79 { 80 might_sleep(); 81 wait_on_bit(&inode->i_state, __I_LOCK, inode_wait, 82 TASK_UNINTERRUPTIBLE); 83 } 84 85 /* 86 * mm/page-writeback.c 87 */ 88 int wakeup_pdflush(long nr_pages); 89 void laptop_io_completion(void); 90 void laptop_sync_completion(void); 91 void throttle_vm_writeout(gfp_t gfp_mask); 92 93 /* These are exported to sysctl. */ 94 extern int dirty_background_ratio; 95 extern int vm_dirty_ratio; 96 extern int dirty_writeback_interval; 97 extern int dirty_expire_interval; 98 extern int block_dump; 99 extern int laptop_mode; 100 101 struct ctl_table; 102 struct file; 103 int dirty_writeback_centisecs_handler(struct ctl_table *, int, struct file *, 104 void __user *, size_t *, loff_t *); 105 106 void page_writeback_init(void); 107 void balance_dirty_pages_ratelimited_nr(struct address_space *mapping, 108 unsigned long nr_pages_dirtied); 109 110 static inline void 111 balance_dirty_pages_ratelimited(struct address_space *mapping) 112 { 113 balance_dirty_pages_ratelimited_nr(mapping, 1); 114 } 115 116 typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc, 117 void *data); 118 119 int pdflush_operation(void (*fn)(unsigned long), unsigned long arg0); 120 int generic_writepages(struct address_space *mapping, 121 struct writeback_control *wbc); 122 int write_cache_pages(struct address_space *mapping, 123 struct writeback_control *wbc, writepage_t writepage, 124 void *data); 125 int do_writepages(struct address_space *mapping, struct writeback_control *wbc); 126 int sync_page_range(struct inode *inode, struct address_space *mapping, 127 loff_t pos, loff_t count); 128 int sync_page_range_nolock(struct inode *inode, struct address_space *mapping, 129 loff_t pos, loff_t count); 130 void set_page_dirty_balance(struct page *page); 131 void writeback_set_ratelimit(void); 132 133 /* pdflush.c */ 134 extern int nr_pdflush_threads; /* Global so it can be exported to sysctl 135 read-only. */ 136 137 138 #endif /* WRITEBACK_H */ 139