1/* 2 * include/linux/writeback.h 3 */ 4#ifndef WRITEBACK_H 5#define WRITEBACK_H 6 7#include <linux/sched.h> 8 9struct backing_dev_info; 10 11extern spinlock_t inode_lock; 12extern struct list_head inode_in_use; 13extern struct list_head inode_unused; 14 15/* 16 * Yes, writeback.h requires sched.h 17 * No, sched.h is not included from here. 18 */ 19static 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 */ 29enum 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 */ 40struct 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 */ 71void writeback_inodes(struct writeback_control *wbc); 72void wake_up_inode(struct inode *inode); 73int inode_wait(void *); 74void sync_inodes_sb(struct super_block *, int wait); 75void sync_inodes(int wait); 76 77/* writeback.h requires fs.h; it, too, is not included from here. */ 78static 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 */ 88int wakeup_pdflush(long nr_pages); 89void laptop_io_completion(void); 90void laptop_sync_completion(void); 91void throttle_vm_writeout(gfp_t gfp_mask); 92 93/* These are exported to sysctl. */ 94extern int dirty_background_ratio; 95extern int vm_dirty_ratio; 96extern int dirty_writeback_interval; 97extern int dirty_expire_interval; 98extern int block_dump; 99extern int laptop_mode; 100 101struct ctl_table; 102struct file; 103int dirty_writeback_centisecs_handler(struct ctl_table *, int, struct file *, 104 void __user *, size_t *, loff_t *); 105 106void page_writeback_init(void); 107void balance_dirty_pages_ratelimited_nr(struct address_space *mapping, 108 unsigned long nr_pages_dirtied); 109 110static inline void 111balance_dirty_pages_ratelimited(struct address_space *mapping) 112{ 113 balance_dirty_pages_ratelimited_nr(mapping, 1); 114} 115 116typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc, 117 void *data); 118 119int pdflush_operation(void (*fn)(unsigned long), unsigned long arg0); 120int generic_writepages(struct address_space *mapping, 121 struct writeback_control *wbc); 122int write_cache_pages(struct address_space *mapping, 123 struct writeback_control *wbc, writepage_t writepage, 124 void *data); 125int do_writepages(struct address_space *mapping, struct writeback_control *wbc); 126int sync_page_range(struct inode *inode, struct address_space *mapping, 127 loff_t pos, loff_t count); 128int sync_page_range_nolock(struct inode *inode, struct address_space *mapping, 129 loff_t pos, loff_t count); 130void set_page_dirty_balance(struct page *page); 131void writeback_set_ratelimit(void); 132 133/* pdflush.c */ 134extern int nr_pdflush_threads; /* Global so it can be exported to sysctl 135 read-only. */ 136 137 138#endif /* WRITEBACK_H */ 139