1 /* 2 * include/linux/writeback.h 3 */ 4 #ifndef WRITEBACK_H 5 #define WRITEBACK_H 6 7 #include <linux/sched.h> 8 #include <linux/fs.h> 9 10 struct backing_dev_info; 11 12 extern spinlock_t inode_lock; 13 extern struct list_head inode_in_use; 14 extern struct list_head inode_unused; 15 16 /* 17 * Yes, writeback.h requires sched.h 18 * No, sched.h is not included from here. 19 */ 20 static inline int task_is_pdflush(struct task_struct *task) 21 { 22 return task->flags & PF_FLUSHER; 23 } 24 25 #define current_is_pdflush() task_is_pdflush(current) 26 27 /* 28 * fs/fs-writeback.c 29 */ 30 enum writeback_sync_modes { 31 WB_SYNC_NONE, /* Don't wait on anything */ 32 WB_SYNC_ALL, /* Wait on every mapping */ 33 WB_SYNC_HOLD, /* Hold the inode on sb_dirty for sys_sync() */ 34 }; 35 36 /* 37 * A control structure which tells the writeback code what to do. These are 38 * always on the stack, and hence need no locking. They are always initialised 39 * in a manner such that unspecified fields are set to zero. 40 */ 41 struct writeback_control { 42 struct backing_dev_info *bdi; /* If !NULL, only write back this 43 queue */ 44 enum writeback_sync_modes sync_mode; 45 unsigned long *older_than_this; /* If !NULL, only write back inodes 46 older than this */ 47 long nr_to_write; /* Write this many pages, and decrement 48 this for each page written */ 49 long pages_skipped; /* Pages which were not written */ 50 51 /* 52 * For a_ops->writepages(): is start or end are non-zero then this is 53 * a hint that the filesystem need only write out the pages inside that 54 * byterange. The byte at `end' is included in the writeout request. 55 */ 56 loff_t range_start; 57 loff_t range_end; 58 59 unsigned nonblocking:1; /* Don't get stuck on request queues */ 60 unsigned encountered_congestion:1; /* An output: a queue is full */ 61 unsigned for_kupdate:1; /* A kupdate writeback */ 62 unsigned for_reclaim:1; /* Invoked from the page allocator */ 63 unsigned for_writepages:1; /* This is a writepages() call */ 64 unsigned range_cyclic:1; /* range_start is cyclic */ 65 }; 66 67 /* 68 * fs/fs-writeback.c 69 */ 70 void writeback_inodes(struct writeback_control *wbc); 71 int inode_wait(void *); 72 void sync_inodes_sb(struct super_block *, int wait); 73 void sync_inodes(int wait); 74 75 /* writeback.h requires fs.h; it, too, is not included from here. */ 76 static inline void wait_on_inode(struct inode *inode) 77 { 78 might_sleep(); 79 wait_on_bit(&inode->i_state, __I_LOCK, inode_wait, 80 TASK_UNINTERRUPTIBLE); 81 } 82 static inline void inode_sync_wait(struct inode *inode) 83 { 84 might_sleep(); 85 wait_on_bit(&inode->i_state, __I_SYNC, inode_wait, 86 TASK_UNINTERRUPTIBLE); 87 } 88 89 90 /* 91 * mm/page-writeback.c 92 */ 93 int wakeup_pdflush(long nr_pages); 94 void laptop_io_completion(void); 95 void laptop_sync_completion(void); 96 void throttle_vm_writeout(gfp_t gfp_mask); 97 98 /* These are exported to sysctl. */ 99 extern int dirty_background_ratio; 100 extern int vm_dirty_ratio; 101 extern int dirty_writeback_interval; 102 extern int dirty_expire_interval; 103 extern int block_dump; 104 extern int laptop_mode; 105 106 extern int dirty_ratio_handler(struct ctl_table *table, int write, 107 struct file *filp, void __user *buffer, size_t *lenp, 108 loff_t *ppos); 109 110 struct ctl_table; 111 struct file; 112 int dirty_writeback_centisecs_handler(struct ctl_table *, int, struct file *, 113 void __user *, size_t *, loff_t *); 114 115 void page_writeback_init(void); 116 void balance_dirty_pages_ratelimited_nr(struct address_space *mapping, 117 unsigned long nr_pages_dirtied); 118 119 static inline void 120 balance_dirty_pages_ratelimited(struct address_space *mapping) 121 { 122 balance_dirty_pages_ratelimited_nr(mapping, 1); 123 } 124 125 typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc, 126 void *data); 127 128 int pdflush_operation(void (*fn)(unsigned long), unsigned long arg0); 129 int generic_writepages(struct address_space *mapping, 130 struct writeback_control *wbc); 131 int write_cache_pages(struct address_space *mapping, 132 struct writeback_control *wbc, writepage_t writepage, 133 void *data); 134 int do_writepages(struct address_space *mapping, struct writeback_control *wbc); 135 int sync_page_range(struct inode *inode, struct address_space *mapping, 136 loff_t pos, loff_t count); 137 int sync_page_range_nolock(struct inode *inode, struct address_space *mapping, 138 loff_t pos, loff_t count); 139 void set_page_dirty_balance(struct page *page, int page_mkwrite); 140 void writeback_set_ratelimit(void); 141 142 /* pdflush.c */ 143 extern int nr_pdflush_threads; /* Global so it can be exported to sysctl 144 read-only. */ 145 146 147 #endif /* WRITEBACK_H */ 148