11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * fs/fs-writeback.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Copyright (C) 2002, Linus Torvalds. 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * Contains all the functions related to writing back and waiting 71da177e4SLinus Torvalds * upon dirty inodes against superblocks, and writing back dirty 81da177e4SLinus Torvalds * pages against inodes. ie: data writeback. Writeout of the 91da177e4SLinus Torvalds * inode itself is not handled here. 101da177e4SLinus Torvalds * 11e1f8e874SFrancois Cami * 10Apr2002 Andrew Morton 121da177e4SLinus Torvalds * Split out of fs/inode.c 131da177e4SLinus Torvalds * Additions for address_space-based writeback 141da177e4SLinus Torvalds */ 151da177e4SLinus Torvalds 161da177e4SLinus Torvalds #include <linux/kernel.h> 17630d9c47SPaul Gortmaker #include <linux/export.h> 181da177e4SLinus Torvalds #include <linux/spinlock.h> 195a0e3ad6STejun Heo #include <linux/slab.h> 201da177e4SLinus Torvalds #include <linux/sched.h> 211da177e4SLinus Torvalds #include <linux/fs.h> 221da177e4SLinus Torvalds #include <linux/mm.h> 23bc31b86aSWu Fengguang #include <linux/pagemap.h> 2403ba3782SJens Axboe #include <linux/kthread.h> 251da177e4SLinus Torvalds #include <linux/writeback.h> 261da177e4SLinus Torvalds #include <linux/blkdev.h> 271da177e4SLinus Torvalds #include <linux/backing-dev.h> 28455b2864SDave Chinner #include <linux/tracepoint.h> 2907f3f05cSDavid Howells #include "internal.h" 301da177e4SLinus Torvalds 31d0bceac7SJens Axboe /* 32bc31b86aSWu Fengguang * 4MB minimal write chunk size 33bc31b86aSWu Fengguang */ 34bc31b86aSWu Fengguang #define MIN_WRITEBACK_PAGES (4096UL >> (PAGE_CACHE_SHIFT - 10)) 35bc31b86aSWu Fengguang 36bc31b86aSWu Fengguang /* 37c4a77a6cSJens Axboe * Passed into wb_writeback(), essentially a subset of writeback_control 38c4a77a6cSJens Axboe */ 3983ba7b07SChristoph Hellwig struct wb_writeback_work { 40c4a77a6cSJens Axboe long nr_pages; 41c4a77a6cSJens Axboe struct super_block *sb; 42d46db3d5SWu Fengguang unsigned long *older_than_this; 43c4a77a6cSJens Axboe enum writeback_sync_modes sync_mode; 446e6938b6SWu Fengguang unsigned int tagged_writepages:1; 4552957fe1SH Hartley Sweeten unsigned int for_kupdate:1; 4652957fe1SH Hartley Sweeten unsigned int range_cyclic:1; 4752957fe1SH Hartley Sweeten unsigned int for_background:1; 487747bd4bSDave Chinner unsigned int for_sync:1; /* sync(2) WB_SYNC_ALL writeback */ 490e175a18SCurt Wohlgemuth enum wb_reason reason; /* why was writeback initiated? */ 50c4a77a6cSJens Axboe 518010c3b6SJens Axboe struct list_head list; /* pending work list */ 5283ba7b07SChristoph Hellwig struct completion *done; /* set if the caller waits */ 5303ba3782SJens Axboe }; 5403ba3782SJens Axboe 55f11b00f3SAdrian Bunk /** 56f11b00f3SAdrian Bunk * writeback_in_progress - determine whether there is writeback in progress 57f11b00f3SAdrian Bunk * @bdi: the device's backing_dev_info structure. 58f11b00f3SAdrian Bunk * 5903ba3782SJens Axboe * Determine whether there is writeback waiting to be handled against a 6003ba3782SJens Axboe * backing device. 61f11b00f3SAdrian Bunk */ 62f11b00f3SAdrian Bunk int writeback_in_progress(struct backing_dev_info *bdi) 63f11b00f3SAdrian Bunk { 6481d73a32SJan Kara return test_bit(BDI_writeback_running, &bdi->state); 65f11b00f3SAdrian Bunk } 6600d4e736STheodore Ts'o EXPORT_SYMBOL(writeback_in_progress); 67f11b00f3SAdrian Bunk 68692ebd17SJan Kara static inline struct backing_dev_info *inode_to_bdi(struct inode *inode) 69692ebd17SJan Kara { 70692ebd17SJan Kara struct super_block *sb = inode->i_sb; 71692ebd17SJan Kara 72aaead25bSChristoph Hellwig if (strcmp(sb->s_type->name, "bdev") == 0) 73aaead25bSChristoph Hellwig return inode->i_mapping->backing_dev_info; 74aaead25bSChristoph Hellwig 75692ebd17SJan Kara return sb->s_bdi; 76692ebd17SJan Kara } 77692ebd17SJan Kara 787ccf19a8SNick Piggin static inline struct inode *wb_inode(struct list_head *head) 797ccf19a8SNick Piggin { 807ccf19a8SNick Piggin return list_entry(head, struct inode, i_wb_list); 817ccf19a8SNick Piggin } 827ccf19a8SNick Piggin 8315eb77a0SWu Fengguang /* 8415eb77a0SWu Fengguang * Include the creation of the trace points after defining the 8515eb77a0SWu Fengguang * wb_writeback_work structure and inline functions so that the definition 8615eb77a0SWu Fengguang * remains local to this file. 8715eb77a0SWu Fengguang */ 8815eb77a0SWu Fengguang #define CREATE_TRACE_POINTS 8915eb77a0SWu Fengguang #include <trace/events/writeback.h> 9015eb77a0SWu Fengguang 916585027aSJan Kara static void bdi_queue_work(struct backing_dev_info *bdi, 926585027aSJan Kara struct wb_writeback_work *work) 936585027aSJan Kara { 946585027aSJan Kara trace_writeback_queue(bdi, work); 956585027aSJan Kara 966585027aSJan Kara spin_lock_bh(&bdi->wb_lock); 976585027aSJan Kara list_add_tail(&work->list, &bdi->work_list); 986467716aSArtem Bityutskiy spin_unlock_bh(&bdi->wb_lock); 99839a8e86STejun Heo 100839a8e86STejun Heo mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); 10103ba3782SJens Axboe } 1021da177e4SLinus Torvalds 10383ba7b07SChristoph Hellwig static void 10483ba7b07SChristoph Hellwig __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, 1050e175a18SCurt Wohlgemuth bool range_cyclic, enum wb_reason reason) 1061da177e4SLinus Torvalds { 10783ba7b07SChristoph Hellwig struct wb_writeback_work *work; 10803ba3782SJens Axboe 109bcddc3f0SJens Axboe /* 110bcddc3f0SJens Axboe * This is WB_SYNC_NONE writeback, so if allocation fails just 111bcddc3f0SJens Axboe * wakeup the thread for old dirty data writeback 112bcddc3f0SJens Axboe */ 11383ba7b07SChristoph Hellwig work = kzalloc(sizeof(*work), GFP_ATOMIC); 11483ba7b07SChristoph Hellwig if (!work) { 115455b2864SDave Chinner trace_writeback_nowork(bdi); 116839a8e86STejun Heo mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); 11783ba7b07SChristoph Hellwig return; 11883ba7b07SChristoph Hellwig } 11983ba7b07SChristoph Hellwig 12083ba7b07SChristoph Hellwig work->sync_mode = WB_SYNC_NONE; 12183ba7b07SChristoph Hellwig work->nr_pages = nr_pages; 12283ba7b07SChristoph Hellwig work->range_cyclic = range_cyclic; 1230e175a18SCurt Wohlgemuth work->reason = reason; 12483ba7b07SChristoph Hellwig 125f11fcae8SJens Axboe bdi_queue_work(bdi, work); 12603ba3782SJens Axboe } 127b6e51316SJens Axboe 128b6e51316SJens Axboe /** 129b6e51316SJens Axboe * bdi_start_writeback - start writeback 130b6e51316SJens Axboe * @bdi: the backing device to write from 131b6e51316SJens Axboe * @nr_pages: the number of pages to write 132786228abSMarcos Paulo de Souza * @reason: reason why some writeback work was initiated 133b6e51316SJens Axboe * 134b6e51316SJens Axboe * Description: 135b6e51316SJens Axboe * This does WB_SYNC_NONE opportunistic writeback. The IO is only 13625985edcSLucas De Marchi * started when this function returns, we make no guarantees on 1370e3c9a22SJens Axboe * completion. Caller need not hold sb s_umount semaphore. 138b6e51316SJens Axboe * 139b6e51316SJens Axboe */ 1400e175a18SCurt Wohlgemuth void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, 1410e175a18SCurt Wohlgemuth enum wb_reason reason) 142b6e51316SJens Axboe { 1430e175a18SCurt Wohlgemuth __bdi_start_writeback(bdi, nr_pages, true, reason); 144d3ddec76SWu Fengguang } 145d3ddec76SWu Fengguang 146c5444198SChristoph Hellwig /** 147c5444198SChristoph Hellwig * bdi_start_background_writeback - start background writeback 148c5444198SChristoph Hellwig * @bdi: the backing device to write from 149c5444198SChristoph Hellwig * 150c5444198SChristoph Hellwig * Description: 1516585027aSJan Kara * This makes sure WB_SYNC_NONE background writeback happens. When 1526585027aSJan Kara * this function returns, it is only guaranteed that for given BDI 1536585027aSJan Kara * some IO is happening if we are over background dirty threshold. 1546585027aSJan Kara * Caller need not hold sb s_umount semaphore. 155c5444198SChristoph Hellwig */ 156c5444198SChristoph Hellwig void bdi_start_background_writeback(struct backing_dev_info *bdi) 157c5444198SChristoph Hellwig { 1586585027aSJan Kara /* 1596585027aSJan Kara * We just wake up the flusher thread. It will perform background 1606585027aSJan Kara * writeback as soon as there is no other work to do. 1616585027aSJan Kara */ 16271927e84SWu Fengguang trace_writeback_wake_background(bdi); 163839a8e86STejun Heo mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); 1641da177e4SLinus Torvalds } 1651da177e4SLinus Torvalds 1661da177e4SLinus Torvalds /* 167a66979abSDave Chinner * Remove the inode from the writeback list it is on. 168a66979abSDave Chinner */ 169a66979abSDave Chinner void inode_wb_list_del(struct inode *inode) 170a66979abSDave Chinner { 171f758eeabSChristoph Hellwig struct backing_dev_info *bdi = inode_to_bdi(inode); 172a66979abSDave Chinner 173f758eeabSChristoph Hellwig spin_lock(&bdi->wb.list_lock); 174f758eeabSChristoph Hellwig list_del_init(&inode->i_wb_list); 175f758eeabSChristoph Hellwig spin_unlock(&bdi->wb.list_lock); 176f758eeabSChristoph Hellwig } 177a66979abSDave Chinner 178a66979abSDave Chinner /* 1796610a0bcSAndrew Morton * Redirty an inode: set its when-it-was dirtied timestamp and move it to the 1806610a0bcSAndrew Morton * furthest end of its superblock's dirty-inode list. 1816610a0bcSAndrew Morton * 1826610a0bcSAndrew Morton * Before stamping the inode's ->dirtied_when, we check to see whether it is 18366f3b8e2SJens Axboe * already the most-recently-dirtied inode on the b_dirty list. If that is 1846610a0bcSAndrew Morton * the case then the inode must have been redirtied while it was being written 1856610a0bcSAndrew Morton * out and we don't reset its dirtied_when. 1866610a0bcSAndrew Morton */ 187f758eeabSChristoph Hellwig static void redirty_tail(struct inode *inode, struct bdi_writeback *wb) 1886610a0bcSAndrew Morton { 189f758eeabSChristoph Hellwig assert_spin_locked(&wb->list_lock); 19003ba3782SJens Axboe if (!list_empty(&wb->b_dirty)) { 19166f3b8e2SJens Axboe struct inode *tail; 1926610a0bcSAndrew Morton 1937ccf19a8SNick Piggin tail = wb_inode(wb->b_dirty.next); 19466f3b8e2SJens Axboe if (time_before(inode->dirtied_when, tail->dirtied_when)) 1956610a0bcSAndrew Morton inode->dirtied_when = jiffies; 1966610a0bcSAndrew Morton } 1977ccf19a8SNick Piggin list_move(&inode->i_wb_list, &wb->b_dirty); 1986610a0bcSAndrew Morton } 1996610a0bcSAndrew Morton 2006610a0bcSAndrew Morton /* 20166f3b8e2SJens Axboe * requeue inode for re-scanning after bdi->b_io list is exhausted. 202c986d1e2SAndrew Morton */ 203f758eeabSChristoph Hellwig static void requeue_io(struct inode *inode, struct bdi_writeback *wb) 204c986d1e2SAndrew Morton { 205f758eeabSChristoph Hellwig assert_spin_locked(&wb->list_lock); 2067ccf19a8SNick Piggin list_move(&inode->i_wb_list, &wb->b_more_io); 207c986d1e2SAndrew Morton } 208c986d1e2SAndrew Morton 2091c0eeaf5SJoern Engel static void inode_sync_complete(struct inode *inode) 2101c0eeaf5SJoern Engel { 211365b94aeSJan Kara inode->i_state &= ~I_SYNC; 2124eff96ddSJan Kara /* If inode is clean an unused, put it into LRU now... */ 2134eff96ddSJan Kara inode_add_lru(inode); 214365b94aeSJan Kara /* Waiters must see I_SYNC cleared before being woken up */ 2151c0eeaf5SJoern Engel smp_mb(); 2161c0eeaf5SJoern Engel wake_up_bit(&inode->i_state, __I_SYNC); 2171c0eeaf5SJoern Engel } 2181c0eeaf5SJoern Engel 219d2caa3c5SJeff Layton static bool inode_dirtied_after(struct inode *inode, unsigned long t) 220d2caa3c5SJeff Layton { 221d2caa3c5SJeff Layton bool ret = time_after(inode->dirtied_when, t); 222d2caa3c5SJeff Layton #ifndef CONFIG_64BIT 223d2caa3c5SJeff Layton /* 224d2caa3c5SJeff Layton * For inodes being constantly redirtied, dirtied_when can get stuck. 225d2caa3c5SJeff Layton * It _appears_ to be in the future, but is actually in distant past. 226d2caa3c5SJeff Layton * This test is necessary to prevent such wrapped-around relative times 2275b0830cbSJens Axboe * from permanently stopping the whole bdi writeback. 228d2caa3c5SJeff Layton */ 229d2caa3c5SJeff Layton ret = ret && time_before_eq(inode->dirtied_when, jiffies); 230d2caa3c5SJeff Layton #endif 231d2caa3c5SJeff Layton return ret; 232d2caa3c5SJeff Layton } 233d2caa3c5SJeff Layton 234c986d1e2SAndrew Morton /* 2350e2f2b23SWang Sheng-Hui * Move expired (dirtied before work->older_than_this) dirty inodes from 236697e6fedSJan Kara * @delaying_queue to @dispatch_queue. 2372c136579SFengguang Wu */ 238e84d0a4fSWu Fengguang static int move_expired_inodes(struct list_head *delaying_queue, 2392c136579SFengguang Wu struct list_head *dispatch_queue, 240ad4e38ddSCurt Wohlgemuth struct wb_writeback_work *work) 2412c136579SFengguang Wu { 2425c03449dSShaohua Li LIST_HEAD(tmp); 2435c03449dSShaohua Li struct list_head *pos, *node; 244cf137307SJens Axboe struct super_block *sb = NULL; 2455c03449dSShaohua Li struct inode *inode; 246cf137307SJens Axboe int do_sb_sort = 0; 247e84d0a4fSWu Fengguang int moved = 0; 2485c03449dSShaohua Li 2492c136579SFengguang Wu while (!list_empty(delaying_queue)) { 2507ccf19a8SNick Piggin inode = wb_inode(delaying_queue->prev); 251ad4e38ddSCurt Wohlgemuth if (work->older_than_this && 252ad4e38ddSCurt Wohlgemuth inode_dirtied_after(inode, *work->older_than_this)) 2532c136579SFengguang Wu break; 254cf137307SJens Axboe if (sb && sb != inode->i_sb) 255cf137307SJens Axboe do_sb_sort = 1; 256cf137307SJens Axboe sb = inode->i_sb; 2577ccf19a8SNick Piggin list_move(&inode->i_wb_list, &tmp); 258e84d0a4fSWu Fengguang moved++; 2595c03449dSShaohua Li } 2605c03449dSShaohua Li 261cf137307SJens Axboe /* just one sb in list, splice to dispatch_queue and we're done */ 262cf137307SJens Axboe if (!do_sb_sort) { 263cf137307SJens Axboe list_splice(&tmp, dispatch_queue); 264e84d0a4fSWu Fengguang goto out; 265cf137307SJens Axboe } 266cf137307SJens Axboe 2675c03449dSShaohua Li /* Move inodes from one superblock together */ 2685c03449dSShaohua Li while (!list_empty(&tmp)) { 2697ccf19a8SNick Piggin sb = wb_inode(tmp.prev)->i_sb; 2705c03449dSShaohua Li list_for_each_prev_safe(pos, node, &tmp) { 2717ccf19a8SNick Piggin inode = wb_inode(pos); 2725c03449dSShaohua Li if (inode->i_sb == sb) 2737ccf19a8SNick Piggin list_move(&inode->i_wb_list, dispatch_queue); 2742c136579SFengguang Wu } 2752c136579SFengguang Wu } 276e84d0a4fSWu Fengguang out: 277e84d0a4fSWu Fengguang return moved; 2785c03449dSShaohua Li } 2792c136579SFengguang Wu 2802c136579SFengguang Wu /* 2812c136579SFengguang Wu * Queue all expired dirty inodes for io, eldest first. 2824ea879b9SWu Fengguang * Before 2834ea879b9SWu Fengguang * newly dirtied b_dirty b_io b_more_io 2844ea879b9SWu Fengguang * =============> gf edc BA 2854ea879b9SWu Fengguang * After 2864ea879b9SWu Fengguang * newly dirtied b_dirty b_io b_more_io 2874ea879b9SWu Fengguang * =============> g fBAedc 2884ea879b9SWu Fengguang * | 2894ea879b9SWu Fengguang * +--> dequeue for IO 2902c136579SFengguang Wu */ 291ad4e38ddSCurt Wohlgemuth static void queue_io(struct bdi_writeback *wb, struct wb_writeback_work *work) 2922c136579SFengguang Wu { 293e84d0a4fSWu Fengguang int moved; 294f758eeabSChristoph Hellwig assert_spin_locked(&wb->list_lock); 2954ea879b9SWu Fengguang list_splice_init(&wb->b_more_io, &wb->b_io); 296ad4e38ddSCurt Wohlgemuth moved = move_expired_inodes(&wb->b_dirty, &wb->b_io, work); 297ad4e38ddSCurt Wohlgemuth trace_writeback_queue_io(wb, work, moved); 29866f3b8e2SJens Axboe } 29966f3b8e2SJens Axboe 300a9185b41SChristoph Hellwig static int write_inode(struct inode *inode, struct writeback_control *wbc) 30166f3b8e2SJens Axboe { 3029fb0a7daSTejun Heo int ret; 3039fb0a7daSTejun Heo 3049fb0a7daSTejun Heo if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) { 3059fb0a7daSTejun Heo trace_writeback_write_inode_start(inode, wbc); 3069fb0a7daSTejun Heo ret = inode->i_sb->s_op->write_inode(inode, wbc); 3079fb0a7daSTejun Heo trace_writeback_write_inode(inode, wbc); 3089fb0a7daSTejun Heo return ret; 3099fb0a7daSTejun Heo } 31003ba3782SJens Axboe return 0; 31166f3b8e2SJens Axboe } 31208d8e974SFengguang Wu 3132c136579SFengguang Wu /* 314169ebd90SJan Kara * Wait for writeback on an inode to complete. Called with i_lock held. 315169ebd90SJan Kara * Caller must make sure inode cannot go away when we drop i_lock. 31601c03194SChristoph Hellwig */ 317169ebd90SJan Kara static void __inode_wait_for_writeback(struct inode *inode) 318169ebd90SJan Kara __releases(inode->i_lock) 319169ebd90SJan Kara __acquires(inode->i_lock) 32001c03194SChristoph Hellwig { 32101c03194SChristoph Hellwig DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); 32201c03194SChristoph Hellwig wait_queue_head_t *wqh; 32301c03194SChristoph Hellwig 32401c03194SChristoph Hellwig wqh = bit_waitqueue(&inode->i_state, __I_SYNC); 32558a9d3d8SRichard Kennedy while (inode->i_state & I_SYNC) { 326250df6edSDave Chinner spin_unlock(&inode->i_lock); 32701c03194SChristoph Hellwig __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE); 328250df6edSDave Chinner spin_lock(&inode->i_lock); 32958a9d3d8SRichard Kennedy } 33001c03194SChristoph Hellwig } 33101c03194SChristoph Hellwig 33201c03194SChristoph Hellwig /* 333169ebd90SJan Kara * Wait for writeback on an inode to complete. Caller must have inode pinned. 334169ebd90SJan Kara */ 335169ebd90SJan Kara void inode_wait_for_writeback(struct inode *inode) 336169ebd90SJan Kara { 337169ebd90SJan Kara spin_lock(&inode->i_lock); 338169ebd90SJan Kara __inode_wait_for_writeback(inode); 339169ebd90SJan Kara spin_unlock(&inode->i_lock); 340169ebd90SJan Kara } 341169ebd90SJan Kara 342169ebd90SJan Kara /* 343169ebd90SJan Kara * Sleep until I_SYNC is cleared. This function must be called with i_lock 344169ebd90SJan Kara * held and drops it. It is aimed for callers not holding any inode reference 345169ebd90SJan Kara * so once i_lock is dropped, inode can go away. 346169ebd90SJan Kara */ 347169ebd90SJan Kara static void inode_sleep_on_writeback(struct inode *inode) 348169ebd90SJan Kara __releases(inode->i_lock) 349169ebd90SJan Kara { 350169ebd90SJan Kara DEFINE_WAIT(wait); 351169ebd90SJan Kara wait_queue_head_t *wqh = bit_waitqueue(&inode->i_state, __I_SYNC); 352169ebd90SJan Kara int sleep; 353169ebd90SJan Kara 354169ebd90SJan Kara prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); 355169ebd90SJan Kara sleep = inode->i_state & I_SYNC; 356169ebd90SJan Kara spin_unlock(&inode->i_lock); 357169ebd90SJan Kara if (sleep) 358169ebd90SJan Kara schedule(); 359169ebd90SJan Kara finish_wait(wqh, &wait); 360169ebd90SJan Kara } 361169ebd90SJan Kara 362169ebd90SJan Kara /* 363ccb26b5aSJan Kara * Find proper writeback list for the inode depending on its current state and 364ccb26b5aSJan Kara * possibly also change of its state while we were doing writeback. Here we 365ccb26b5aSJan Kara * handle things such as livelock prevention or fairness of writeback among 366ccb26b5aSJan Kara * inodes. This function can be called only by flusher thread - noone else 367ccb26b5aSJan Kara * processes all inodes in writeback lists and requeueing inodes behind flusher 368ccb26b5aSJan Kara * thread's back can have unexpected consequences. 369ccb26b5aSJan Kara */ 370ccb26b5aSJan Kara static void requeue_inode(struct inode *inode, struct bdi_writeback *wb, 371ccb26b5aSJan Kara struct writeback_control *wbc) 372ccb26b5aSJan Kara { 373ccb26b5aSJan Kara if (inode->i_state & I_FREEING) 374ccb26b5aSJan Kara return; 375ccb26b5aSJan Kara 376ccb26b5aSJan Kara /* 377ccb26b5aSJan Kara * Sync livelock prevention. Each inode is tagged and synced in one 378ccb26b5aSJan Kara * shot. If still dirty, it will be redirty_tail()'ed below. Update 379ccb26b5aSJan Kara * the dirty time to prevent enqueue and sync it again. 380ccb26b5aSJan Kara */ 381ccb26b5aSJan Kara if ((inode->i_state & I_DIRTY) && 382ccb26b5aSJan Kara (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)) 383ccb26b5aSJan Kara inode->dirtied_when = jiffies; 384ccb26b5aSJan Kara 3854f8ad655SJan Kara if (wbc->pages_skipped) { 3864f8ad655SJan Kara /* 3874f8ad655SJan Kara * writeback is not making progress due to locked 3884f8ad655SJan Kara * buffers. Skip this inode for now. 3894f8ad655SJan Kara */ 3904f8ad655SJan Kara redirty_tail(inode, wb); 3914f8ad655SJan Kara return; 3924f8ad655SJan Kara } 3934f8ad655SJan Kara 394ccb26b5aSJan Kara if (mapping_tagged(inode->i_mapping, PAGECACHE_TAG_DIRTY)) { 395ccb26b5aSJan Kara /* 396ccb26b5aSJan Kara * We didn't write back all the pages. nfs_writepages() 397ccb26b5aSJan Kara * sometimes bales out without doing anything. 398ccb26b5aSJan Kara */ 399ccb26b5aSJan Kara if (wbc->nr_to_write <= 0) { 400ccb26b5aSJan Kara /* Slice used up. Queue for next turn. */ 401ccb26b5aSJan Kara requeue_io(inode, wb); 402ccb26b5aSJan Kara } else { 403ccb26b5aSJan Kara /* 404ccb26b5aSJan Kara * Writeback blocked by something other than 405ccb26b5aSJan Kara * congestion. Delay the inode for some time to 406ccb26b5aSJan Kara * avoid spinning on the CPU (100% iowait) 407ccb26b5aSJan Kara * retrying writeback of the dirty page/inode 408ccb26b5aSJan Kara * that cannot be performed immediately. 409ccb26b5aSJan Kara */ 410ccb26b5aSJan Kara redirty_tail(inode, wb); 411ccb26b5aSJan Kara } 412ccb26b5aSJan Kara } else if (inode->i_state & I_DIRTY) { 413ccb26b5aSJan Kara /* 414ccb26b5aSJan Kara * Filesystems can dirty the inode during writeback operations, 415ccb26b5aSJan Kara * such as delayed allocation during submission or metadata 416ccb26b5aSJan Kara * updates after data IO completion. 417ccb26b5aSJan Kara */ 418ccb26b5aSJan Kara redirty_tail(inode, wb); 419ccb26b5aSJan Kara } else { 420ccb26b5aSJan Kara /* The inode is clean. Remove from writeback lists. */ 421ccb26b5aSJan Kara list_del_init(&inode->i_wb_list); 422ccb26b5aSJan Kara } 423ccb26b5aSJan Kara } 424ccb26b5aSJan Kara 425ccb26b5aSJan Kara /* 4264f8ad655SJan Kara * Write out an inode and its dirty pages. Do not update the writeback list 4274f8ad655SJan Kara * linkage. That is left to the caller. The caller is also responsible for 4284f8ad655SJan Kara * setting I_SYNC flag and calling inode_sync_complete() to clear it. 4291da177e4SLinus Torvalds */ 4301da177e4SLinus Torvalds static int 431cd8ed2a4SYan Hong __writeback_single_inode(struct inode *inode, struct writeback_control *wbc) 4321da177e4SLinus Torvalds { 4331da177e4SLinus Torvalds struct address_space *mapping = inode->i_mapping; 434251d6a47SWu Fengguang long nr_to_write = wbc->nr_to_write; 43501c03194SChristoph Hellwig unsigned dirty; 4361da177e4SLinus Torvalds int ret; 4371da177e4SLinus Torvalds 4384f8ad655SJan Kara WARN_ON(!(inode->i_state & I_SYNC)); 4391da177e4SLinus Torvalds 4409fb0a7daSTejun Heo trace_writeback_single_inode_start(inode, wbc, nr_to_write); 4419fb0a7daSTejun Heo 4421da177e4SLinus Torvalds ret = do_writepages(mapping, wbc); 4431da177e4SLinus Torvalds 44426821ed4SChristoph Hellwig /* 44526821ed4SChristoph Hellwig * Make sure to wait on the data before writing out the metadata. 44626821ed4SChristoph Hellwig * This is important for filesystems that modify metadata on data 4477747bd4bSDave Chinner * I/O completion. We don't do it for sync(2) writeback because it has a 4487747bd4bSDave Chinner * separate, external IO completion path and ->sync_fs for guaranteeing 4497747bd4bSDave Chinner * inode metadata is written back correctly. 45026821ed4SChristoph Hellwig */ 4517747bd4bSDave Chinner if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync) { 45226821ed4SChristoph Hellwig int err = filemap_fdatawait(mapping); 4531da177e4SLinus Torvalds if (ret == 0) 4541da177e4SLinus Torvalds ret = err; 4551da177e4SLinus Torvalds } 4561da177e4SLinus Torvalds 4575547e8aaSDmitry Monakhov /* 4585547e8aaSDmitry Monakhov * Some filesystems may redirty the inode during the writeback 4595547e8aaSDmitry Monakhov * due to delalloc, clear dirty metadata flags right before 4605547e8aaSDmitry Monakhov * write_inode() 4615547e8aaSDmitry Monakhov */ 462250df6edSDave Chinner spin_lock(&inode->i_lock); 4636290be1cSJan Kara /* Clear I_DIRTY_PAGES if we've written out all dirty pages */ 4646290be1cSJan Kara if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) 4656290be1cSJan Kara inode->i_state &= ~I_DIRTY_PAGES; 4665547e8aaSDmitry Monakhov dirty = inode->i_state & I_DIRTY; 4675547e8aaSDmitry Monakhov inode->i_state &= ~(I_DIRTY_SYNC | I_DIRTY_DATASYNC); 468250df6edSDave Chinner spin_unlock(&inode->i_lock); 46926821ed4SChristoph Hellwig /* Don't write the inode if only I_DIRTY_PAGES was set */ 47026821ed4SChristoph Hellwig if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { 471a9185b41SChristoph Hellwig int err = write_inode(inode, wbc); 4721da177e4SLinus Torvalds if (ret == 0) 4731da177e4SLinus Torvalds ret = err; 4741da177e4SLinus Torvalds } 4754f8ad655SJan Kara trace_writeback_single_inode(inode, wbc, nr_to_write); 4764f8ad655SJan Kara return ret; 4774f8ad655SJan Kara } 4784f8ad655SJan Kara 4794f8ad655SJan Kara /* 4804f8ad655SJan Kara * Write out an inode's dirty pages. Either the caller has an active reference 4814f8ad655SJan Kara * on the inode or the inode has I_WILL_FREE set. 4824f8ad655SJan Kara * 4834f8ad655SJan Kara * This function is designed to be called for writing back one inode which 4844f8ad655SJan Kara * we go e.g. from filesystem. Flusher thread uses __writeback_single_inode() 4854f8ad655SJan Kara * and does more profound writeback list handling in writeback_sb_inodes(). 4864f8ad655SJan Kara */ 4874f8ad655SJan Kara static int 4884f8ad655SJan Kara writeback_single_inode(struct inode *inode, struct bdi_writeback *wb, 4894f8ad655SJan Kara struct writeback_control *wbc) 4904f8ad655SJan Kara { 4914f8ad655SJan Kara int ret = 0; 4924f8ad655SJan Kara 4934f8ad655SJan Kara spin_lock(&inode->i_lock); 4944f8ad655SJan Kara if (!atomic_read(&inode->i_count)) 4954f8ad655SJan Kara WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); 4964f8ad655SJan Kara else 4974f8ad655SJan Kara WARN_ON(inode->i_state & I_WILL_FREE); 4984f8ad655SJan Kara 4994f8ad655SJan Kara if (inode->i_state & I_SYNC) { 5004f8ad655SJan Kara if (wbc->sync_mode != WB_SYNC_ALL) 5014f8ad655SJan Kara goto out; 5024f8ad655SJan Kara /* 503169ebd90SJan Kara * It's a data-integrity sync. We must wait. Since callers hold 504169ebd90SJan Kara * inode reference or inode has I_WILL_FREE set, it cannot go 505169ebd90SJan Kara * away under us. 5064f8ad655SJan Kara */ 507169ebd90SJan Kara __inode_wait_for_writeback(inode); 5084f8ad655SJan Kara } 5094f8ad655SJan Kara WARN_ON(inode->i_state & I_SYNC); 5104f8ad655SJan Kara /* 5114f8ad655SJan Kara * Skip inode if it is clean. We don't want to mess with writeback 5124f8ad655SJan Kara * lists in this function since flusher thread may be doing for example 5134f8ad655SJan Kara * sync in parallel and if we move the inode, it could get skipped. So 5144f8ad655SJan Kara * here we make sure inode is on some writeback list and leave it there 5154f8ad655SJan Kara * unless we have completely cleaned the inode. 5164f8ad655SJan Kara */ 5174f8ad655SJan Kara if (!(inode->i_state & I_DIRTY)) 5184f8ad655SJan Kara goto out; 5194f8ad655SJan Kara inode->i_state |= I_SYNC; 5204f8ad655SJan Kara spin_unlock(&inode->i_lock); 5214f8ad655SJan Kara 522cd8ed2a4SYan Hong ret = __writeback_single_inode(inode, wbc); 5231da177e4SLinus Torvalds 524f758eeabSChristoph Hellwig spin_lock(&wb->list_lock); 525250df6edSDave Chinner spin_lock(&inode->i_lock); 5264f8ad655SJan Kara /* 5274f8ad655SJan Kara * If inode is clean, remove it from writeback lists. Otherwise don't 5284f8ad655SJan Kara * touch it. See comment above for explanation. 5294f8ad655SJan Kara */ 5304f8ad655SJan Kara if (!(inode->i_state & I_DIRTY)) 5314f8ad655SJan Kara list_del_init(&inode->i_wb_list); 5324f8ad655SJan Kara spin_unlock(&wb->list_lock); 5331c0eeaf5SJoern Engel inode_sync_complete(inode); 5344f8ad655SJan Kara out: 5354f8ad655SJan Kara spin_unlock(&inode->i_lock); 5361da177e4SLinus Torvalds return ret; 5371da177e4SLinus Torvalds } 5381da177e4SLinus Torvalds 5391a12d8bdSWu Fengguang static long writeback_chunk_size(struct backing_dev_info *bdi, 5401a12d8bdSWu Fengguang struct wb_writeback_work *work) 541d46db3d5SWu Fengguang { 542d46db3d5SWu Fengguang long pages; 543d46db3d5SWu Fengguang 544d46db3d5SWu Fengguang /* 545d46db3d5SWu Fengguang * WB_SYNC_ALL mode does livelock avoidance by syncing dirty 546d46db3d5SWu Fengguang * inodes/pages in one big loop. Setting wbc.nr_to_write=LONG_MAX 547d46db3d5SWu Fengguang * here avoids calling into writeback_inodes_wb() more than once. 548d46db3d5SWu Fengguang * 549d46db3d5SWu Fengguang * The intended call sequence for WB_SYNC_ALL writeback is: 550d46db3d5SWu Fengguang * 551d46db3d5SWu Fengguang * wb_writeback() 552d46db3d5SWu Fengguang * writeback_sb_inodes() <== called only once 553d46db3d5SWu Fengguang * write_cache_pages() <== called once for each inode 554d46db3d5SWu Fengguang * (quickly) tag currently dirty pages 555d46db3d5SWu Fengguang * (maybe slowly) sync all tagged pages 556d46db3d5SWu Fengguang */ 557d46db3d5SWu Fengguang if (work->sync_mode == WB_SYNC_ALL || work->tagged_writepages) 558d46db3d5SWu Fengguang pages = LONG_MAX; 5591a12d8bdSWu Fengguang else { 5601a12d8bdSWu Fengguang pages = min(bdi->avg_write_bandwidth / 2, 5611a12d8bdSWu Fengguang global_dirty_limit / DIRTY_SCOPE); 5621a12d8bdSWu Fengguang pages = min(pages, work->nr_pages); 5631a12d8bdSWu Fengguang pages = round_down(pages + MIN_WRITEBACK_PAGES, 5641a12d8bdSWu Fengguang MIN_WRITEBACK_PAGES); 5651a12d8bdSWu Fengguang } 566d46db3d5SWu Fengguang 567d46db3d5SWu Fengguang return pages; 568d46db3d5SWu Fengguang } 569d46db3d5SWu Fengguang 57003ba3782SJens Axboe /* 571f11c9c5cSEdward Shishkin * Write a portion of b_io inodes which belong to @sb. 572edadfb10SChristoph Hellwig * 573d46db3d5SWu Fengguang * Return the number of pages and/or inodes written. 574f11c9c5cSEdward Shishkin */ 575d46db3d5SWu Fengguang static long writeback_sb_inodes(struct super_block *sb, 576d46db3d5SWu Fengguang struct bdi_writeback *wb, 577d46db3d5SWu Fengguang struct wb_writeback_work *work) 57803ba3782SJens Axboe { 579d46db3d5SWu Fengguang struct writeback_control wbc = { 580d46db3d5SWu Fengguang .sync_mode = work->sync_mode, 581d46db3d5SWu Fengguang .tagged_writepages = work->tagged_writepages, 582d46db3d5SWu Fengguang .for_kupdate = work->for_kupdate, 583d46db3d5SWu Fengguang .for_background = work->for_background, 5847747bd4bSDave Chinner .for_sync = work->for_sync, 585d46db3d5SWu Fengguang .range_cyclic = work->range_cyclic, 586d46db3d5SWu Fengguang .range_start = 0, 587d46db3d5SWu Fengguang .range_end = LLONG_MAX, 588d46db3d5SWu Fengguang }; 589d46db3d5SWu Fengguang unsigned long start_time = jiffies; 590d46db3d5SWu Fengguang long write_chunk; 591d46db3d5SWu Fengguang long wrote = 0; /* count both pages and inodes */ 592d46db3d5SWu Fengguang 59303ba3782SJens Axboe while (!list_empty(&wb->b_io)) { 5947ccf19a8SNick Piggin struct inode *inode = wb_inode(wb->b_io.prev); 595edadfb10SChristoph Hellwig 596edadfb10SChristoph Hellwig if (inode->i_sb != sb) { 597d46db3d5SWu Fengguang if (work->sb) { 598edadfb10SChristoph Hellwig /* 599edadfb10SChristoph Hellwig * We only want to write back data for this 600edadfb10SChristoph Hellwig * superblock, move all inodes not belonging 601edadfb10SChristoph Hellwig * to it back onto the dirty list. 602edadfb10SChristoph Hellwig */ 603f758eeabSChristoph Hellwig redirty_tail(inode, wb); 60466f3b8e2SJens Axboe continue; 60566f3b8e2SJens Axboe } 606edadfb10SChristoph Hellwig 607edadfb10SChristoph Hellwig /* 608edadfb10SChristoph Hellwig * The inode belongs to a different superblock. 609edadfb10SChristoph Hellwig * Bounce back to the caller to unpin this and 610edadfb10SChristoph Hellwig * pin the next superblock. 611edadfb10SChristoph Hellwig */ 612d46db3d5SWu Fengguang break; 613edadfb10SChristoph Hellwig } 614edadfb10SChristoph Hellwig 6159843b76aSChristoph Hellwig /* 616331cbdeeSWanpeng Li * Don't bother with new inodes or inodes being freed, first 617331cbdeeSWanpeng Li * kind does not need periodic writeout yet, and for the latter 6189843b76aSChristoph Hellwig * kind writeout is handled by the freer. 6199843b76aSChristoph Hellwig */ 620250df6edSDave Chinner spin_lock(&inode->i_lock); 6219843b76aSChristoph Hellwig if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { 622250df6edSDave Chinner spin_unlock(&inode->i_lock); 623fcc5c222SWu Fengguang redirty_tail(inode, wb); 6247ef0d737SNick Piggin continue; 6257ef0d737SNick Piggin } 626cc1676d9SJan Kara if ((inode->i_state & I_SYNC) && wbc.sync_mode != WB_SYNC_ALL) { 627cc1676d9SJan Kara /* 628cc1676d9SJan Kara * If this inode is locked for writeback and we are not 629cc1676d9SJan Kara * doing writeback-for-data-integrity, move it to 630cc1676d9SJan Kara * b_more_io so that writeback can proceed with the 631cc1676d9SJan Kara * other inodes on s_io. 632cc1676d9SJan Kara * 633cc1676d9SJan Kara * We'll have another go at writing back this inode 634cc1676d9SJan Kara * when we completed a full scan of b_io. 635cc1676d9SJan Kara */ 636cc1676d9SJan Kara spin_unlock(&inode->i_lock); 637cc1676d9SJan Kara requeue_io(inode, wb); 638cc1676d9SJan Kara trace_writeback_sb_inodes_requeue(inode); 639cc1676d9SJan Kara continue; 640cc1676d9SJan Kara } 641f0d07b7fSJan Kara spin_unlock(&wb->list_lock); 642f0d07b7fSJan Kara 6434f8ad655SJan Kara /* 6444f8ad655SJan Kara * We already requeued the inode if it had I_SYNC set and we 6454f8ad655SJan Kara * are doing WB_SYNC_NONE writeback. So this catches only the 6464f8ad655SJan Kara * WB_SYNC_ALL case. 6474f8ad655SJan Kara */ 648169ebd90SJan Kara if (inode->i_state & I_SYNC) { 649169ebd90SJan Kara /* Wait for I_SYNC. This function drops i_lock... */ 650169ebd90SJan Kara inode_sleep_on_writeback(inode); 651169ebd90SJan Kara /* Inode may be gone, start again */ 652ead188f9SJan Kara spin_lock(&wb->list_lock); 653169ebd90SJan Kara continue; 654169ebd90SJan Kara } 6554f8ad655SJan Kara inode->i_state |= I_SYNC; 6564f8ad655SJan Kara spin_unlock(&inode->i_lock); 657169ebd90SJan Kara 6581a12d8bdSWu Fengguang write_chunk = writeback_chunk_size(wb->bdi, work); 659d46db3d5SWu Fengguang wbc.nr_to_write = write_chunk; 660d46db3d5SWu Fengguang wbc.pages_skipped = 0; 661250df6edSDave Chinner 662169ebd90SJan Kara /* 663169ebd90SJan Kara * We use I_SYNC to pin the inode in memory. While it is set 664169ebd90SJan Kara * evict_inode() will wait so the inode cannot be freed. 665169ebd90SJan Kara */ 666cd8ed2a4SYan Hong __writeback_single_inode(inode, &wbc); 667d46db3d5SWu Fengguang 668d46db3d5SWu Fengguang work->nr_pages -= write_chunk - wbc.nr_to_write; 669d46db3d5SWu Fengguang wrote += write_chunk - wbc.nr_to_write; 6704f8ad655SJan Kara spin_lock(&wb->list_lock); 6714f8ad655SJan Kara spin_lock(&inode->i_lock); 672d46db3d5SWu Fengguang if (!(inode->i_state & I_DIRTY)) 673d46db3d5SWu Fengguang wrote++; 6744f8ad655SJan Kara requeue_inode(inode, wb, &wbc); 6754f8ad655SJan Kara inode_sync_complete(inode); 6760f1b1fd8SDave Chinner spin_unlock(&inode->i_lock); 677169ebd90SJan Kara cond_resched_lock(&wb->list_lock); 678d46db3d5SWu Fengguang /* 679d46db3d5SWu Fengguang * bail out to wb_writeback() often enough to check 680d46db3d5SWu Fengguang * background threshold and other termination conditions. 681d46db3d5SWu Fengguang */ 682d46db3d5SWu Fengguang if (wrote) { 683d46db3d5SWu Fengguang if (time_is_before_jiffies(start_time + HZ / 10UL)) 684d46db3d5SWu Fengguang break; 685d46db3d5SWu Fengguang if (work->nr_pages <= 0) 686d46db3d5SWu Fengguang break; 6871da177e4SLinus Torvalds } 6888bc3be27SFengguang Wu } 689d46db3d5SWu Fengguang return wrote; 690f11c9c5cSEdward Shishkin } 69138f21977SNick Piggin 692d46db3d5SWu Fengguang static long __writeback_inodes_wb(struct bdi_writeback *wb, 693d46db3d5SWu Fengguang struct wb_writeback_work *work) 694f11c9c5cSEdward Shishkin { 695d46db3d5SWu Fengguang unsigned long start_time = jiffies; 696d46db3d5SWu Fengguang long wrote = 0; 697f11c9c5cSEdward Shishkin 698f11c9c5cSEdward Shishkin while (!list_empty(&wb->b_io)) { 6997ccf19a8SNick Piggin struct inode *inode = wb_inode(wb->b_io.prev); 700f11c9c5cSEdward Shishkin struct super_block *sb = inode->i_sb; 701f11c9c5cSEdward Shishkin 70212ad3ab6SDave Chinner if (!grab_super_passive(sb)) { 7030e995816SWu Fengguang /* 7040e995816SWu Fengguang * grab_super_passive() may fail consistently due to 7050e995816SWu Fengguang * s_umount being grabbed by someone else. Don't use 7060e995816SWu Fengguang * requeue_io() to avoid busy retrying the inode/sb. 7070e995816SWu Fengguang */ 7080e995816SWu Fengguang redirty_tail(inode, wb); 709d19de7edSChristoph Hellwig continue; 710334132aeSChristoph Hellwig } 711d46db3d5SWu Fengguang wrote += writeback_sb_inodes(sb, wb, work); 712d19de7edSChristoph Hellwig drop_super(sb); 713f11c9c5cSEdward Shishkin 714d46db3d5SWu Fengguang /* refer to the same tests at the end of writeback_sb_inodes */ 715d46db3d5SWu Fengguang if (wrote) { 716d46db3d5SWu Fengguang if (time_is_before_jiffies(start_time + HZ / 10UL)) 717d46db3d5SWu Fengguang break; 718d46db3d5SWu Fengguang if (work->nr_pages <= 0) 719f11c9c5cSEdward Shishkin break; 720f11c9c5cSEdward Shishkin } 721d46db3d5SWu Fengguang } 72266f3b8e2SJens Axboe /* Leave any unwritten inodes on b_io */ 723d46db3d5SWu Fengguang return wrote; 72466f3b8e2SJens Axboe } 72566f3b8e2SJens Axboe 7260e175a18SCurt Wohlgemuth long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages, 7270e175a18SCurt Wohlgemuth enum wb_reason reason) 728edadfb10SChristoph Hellwig { 729d46db3d5SWu Fengguang struct wb_writeback_work work = { 730d46db3d5SWu Fengguang .nr_pages = nr_pages, 731d46db3d5SWu Fengguang .sync_mode = WB_SYNC_NONE, 732d46db3d5SWu Fengguang .range_cyclic = 1, 7330e175a18SCurt Wohlgemuth .reason = reason, 734d46db3d5SWu Fengguang }; 735edadfb10SChristoph Hellwig 736f758eeabSChristoph Hellwig spin_lock(&wb->list_lock); 737424b351fSWu Fengguang if (list_empty(&wb->b_io)) 738ad4e38ddSCurt Wohlgemuth queue_io(wb, &work); 739d46db3d5SWu Fengguang __writeback_inodes_wb(wb, &work); 740f758eeabSChristoph Hellwig spin_unlock(&wb->list_lock); 741edadfb10SChristoph Hellwig 742d46db3d5SWu Fengguang return nr_pages - work.nr_pages; 74366f3b8e2SJens Axboe } 74466f3b8e2SJens Axboe 745b00949aaSWu Fengguang static bool over_bground_thresh(struct backing_dev_info *bdi) 74603ba3782SJens Axboe { 74703ba3782SJens Axboe unsigned long background_thresh, dirty_thresh; 74803ba3782SJens Axboe 74916c4042fSWu Fengguang global_dirty_limits(&background_thresh, &dirty_thresh); 75003ba3782SJens Axboe 751b00949aaSWu Fengguang if (global_page_state(NR_FILE_DIRTY) + 752b00949aaSWu Fengguang global_page_state(NR_UNSTABLE_NFS) > background_thresh) 753b00949aaSWu Fengguang return true; 754b00949aaSWu Fengguang 755b00949aaSWu Fengguang if (bdi_stat(bdi, BDI_RECLAIMABLE) > 756b00949aaSWu Fengguang bdi_dirty_limit(bdi, background_thresh)) 757b00949aaSWu Fengguang return true; 758b00949aaSWu Fengguang 759b00949aaSWu Fengguang return false; 76003ba3782SJens Axboe } 76103ba3782SJens Axboe 76203ba3782SJens Axboe /* 763e98be2d5SWu Fengguang * Called under wb->list_lock. If there are multiple wb per bdi, 764e98be2d5SWu Fengguang * only the flusher working on the first wb should do it. 765e98be2d5SWu Fengguang */ 766e98be2d5SWu Fengguang static void wb_update_bandwidth(struct bdi_writeback *wb, 767e98be2d5SWu Fengguang unsigned long start_time) 768e98be2d5SWu Fengguang { 769af6a3113SWu Fengguang __bdi_update_bandwidth(wb->bdi, 0, 0, 0, 0, 0, start_time); 770e98be2d5SWu Fengguang } 771e98be2d5SWu Fengguang 772e98be2d5SWu Fengguang /* 77303ba3782SJens Axboe * Explicit flushing or periodic writeback of "old" data. 77403ba3782SJens Axboe * 77503ba3782SJens Axboe * Define "old": the first time one of an inode's pages is dirtied, we mark the 77603ba3782SJens Axboe * dirtying-time in the inode's address_space. So this periodic writeback code 77703ba3782SJens Axboe * just walks the superblock inode list, writing back any inodes which are 77803ba3782SJens Axboe * older than a specific point in time. 77903ba3782SJens Axboe * 78003ba3782SJens Axboe * Try to run once per dirty_writeback_interval. But if a writeback event 78103ba3782SJens Axboe * takes longer than a dirty_writeback_interval interval, then leave a 78203ba3782SJens Axboe * one-second gap. 78303ba3782SJens Axboe * 78403ba3782SJens Axboe * older_than_this takes precedence over nr_to_write. So we'll only write back 78503ba3782SJens Axboe * all dirty pages if they are all attached to "old" mappings. 78603ba3782SJens Axboe */ 787c4a77a6cSJens Axboe static long wb_writeback(struct bdi_writeback *wb, 78883ba7b07SChristoph Hellwig struct wb_writeback_work *work) 78903ba3782SJens Axboe { 790e98be2d5SWu Fengguang unsigned long wb_start = jiffies; 791d46db3d5SWu Fengguang long nr_pages = work->nr_pages; 79203ba3782SJens Axboe unsigned long oldest_jif; 793a5989bdcSJan Kara struct inode *inode; 794d46db3d5SWu Fengguang long progress; 79503ba3782SJens Axboe 796e185dda8SWu Fengguang oldest_jif = jiffies; 797d46db3d5SWu Fengguang work->older_than_this = &oldest_jif; 79803ba3782SJens Axboe 799e8dfc305SWu Fengguang spin_lock(&wb->list_lock); 80003ba3782SJens Axboe for (;;) { 80103ba3782SJens Axboe /* 802d3ddec76SWu Fengguang * Stop writeback when nr_pages has been consumed 80303ba3782SJens Axboe */ 80483ba7b07SChristoph Hellwig if (work->nr_pages <= 0) 80503ba3782SJens Axboe break; 80603ba3782SJens Axboe 80703ba3782SJens Axboe /* 808aa373cf5SJan Kara * Background writeout and kupdate-style writeback may 809aa373cf5SJan Kara * run forever. Stop them if there is other work to do 810aa373cf5SJan Kara * so that e.g. sync can proceed. They'll be restarted 811aa373cf5SJan Kara * after the other works are all done. 812aa373cf5SJan Kara */ 813aa373cf5SJan Kara if ((work->for_background || work->for_kupdate) && 814aa373cf5SJan Kara !list_empty(&wb->bdi->work_list)) 815aa373cf5SJan Kara break; 816aa373cf5SJan Kara 817aa373cf5SJan Kara /* 818d3ddec76SWu Fengguang * For background writeout, stop when we are below the 819d3ddec76SWu Fengguang * background dirty threshold 82003ba3782SJens Axboe */ 821b00949aaSWu Fengguang if (work->for_background && !over_bground_thresh(wb->bdi)) 82203ba3782SJens Axboe break; 82303ba3782SJens Axboe 8241bc36b64SJan Kara /* 8251bc36b64SJan Kara * Kupdate and background works are special and we want to 8261bc36b64SJan Kara * include all inodes that need writing. Livelock avoidance is 8271bc36b64SJan Kara * handled by these works yielding to any other work so we are 8281bc36b64SJan Kara * safe. 8291bc36b64SJan Kara */ 830ba9aa839SWu Fengguang if (work->for_kupdate) { 831ba9aa839SWu Fengguang oldest_jif = jiffies - 832ba9aa839SWu Fengguang msecs_to_jiffies(dirty_expire_interval * 10); 8331bc36b64SJan Kara } else if (work->for_background) 8341bc36b64SJan Kara oldest_jif = jiffies; 835028c2dd1SDave Chinner 836d46db3d5SWu Fengguang trace_writeback_start(wb->bdi, work); 837e8dfc305SWu Fengguang if (list_empty(&wb->b_io)) 838ad4e38ddSCurt Wohlgemuth queue_io(wb, work); 83983ba7b07SChristoph Hellwig if (work->sb) 840d46db3d5SWu Fengguang progress = writeback_sb_inodes(work->sb, wb, work); 841edadfb10SChristoph Hellwig else 842d46db3d5SWu Fengguang progress = __writeback_inodes_wb(wb, work); 843d46db3d5SWu Fengguang trace_writeback_written(wb->bdi, work); 844028c2dd1SDave Chinner 845e98be2d5SWu Fengguang wb_update_bandwidth(wb, wb_start); 84603ba3782SJens Axboe 84703ba3782SJens Axboe /* 84871fd05a8SJens Axboe * Did we write something? Try for more 849e6fb6da2SWu Fengguang * 850e6fb6da2SWu Fengguang * Dirty inodes are moved to b_io for writeback in batches. 851e6fb6da2SWu Fengguang * The completion of the current batch does not necessarily 852e6fb6da2SWu Fengguang * mean the overall work is done. So we keep looping as long 853e6fb6da2SWu Fengguang * as made some progress on cleaning pages or inodes. 85471fd05a8SJens Axboe */ 855d46db3d5SWu Fengguang if (progress) 85603ba3782SJens Axboe continue; 857a5989bdcSJan Kara /* 858e6fb6da2SWu Fengguang * No more inodes for IO, bail 859a5989bdcSJan Kara */ 860b7a2441fSWu Fengguang if (list_empty(&wb->b_more_io)) 86103ba3782SJens Axboe break; 86203ba3782SJens Axboe /* 8638010c3b6SJens Axboe * Nothing written. Wait for some inode to 8648010c3b6SJens Axboe * become available for writeback. Otherwise 8658010c3b6SJens Axboe * we'll just busyloop. 86603ba3782SJens Axboe */ 86703ba3782SJens Axboe if (!list_empty(&wb->b_more_io)) { 868d46db3d5SWu Fengguang trace_writeback_wait(wb->bdi, work); 86903ba3782SJens Axboe inode = wb_inode(wb->b_more_io.prev); 870250df6edSDave Chinner spin_lock(&inode->i_lock); 871f0d07b7fSJan Kara spin_unlock(&wb->list_lock); 872169ebd90SJan Kara /* This function drops i_lock... */ 873169ebd90SJan Kara inode_sleep_on_writeback(inode); 874f0d07b7fSJan Kara spin_lock(&wb->list_lock); 87503ba3782SJens Axboe } 87603ba3782SJens Axboe } 877e8dfc305SWu Fengguang spin_unlock(&wb->list_lock); 87803ba3782SJens Axboe 879d46db3d5SWu Fengguang return nr_pages - work->nr_pages; 88003ba3782SJens Axboe } 88103ba3782SJens Axboe 88203ba3782SJens Axboe /* 88383ba7b07SChristoph Hellwig * Return the next wb_writeback_work struct that hasn't been processed yet. 88403ba3782SJens Axboe */ 88583ba7b07SChristoph Hellwig static struct wb_writeback_work * 88608852b6dSMinchan Kim get_next_work_item(struct backing_dev_info *bdi) 88703ba3782SJens Axboe { 88883ba7b07SChristoph Hellwig struct wb_writeback_work *work = NULL; 88903ba3782SJens Axboe 8906467716aSArtem Bityutskiy spin_lock_bh(&bdi->wb_lock); 89183ba7b07SChristoph Hellwig if (!list_empty(&bdi->work_list)) { 89283ba7b07SChristoph Hellwig work = list_entry(bdi->work_list.next, 89383ba7b07SChristoph Hellwig struct wb_writeback_work, list); 89483ba7b07SChristoph Hellwig list_del_init(&work->list); 89503ba3782SJens Axboe } 8966467716aSArtem Bityutskiy spin_unlock_bh(&bdi->wb_lock); 89783ba7b07SChristoph Hellwig return work; 89803ba3782SJens Axboe } 89903ba3782SJens Axboe 900cdf01dd5SLinus Torvalds /* 901cdf01dd5SLinus Torvalds * Add in the number of potentially dirty inodes, because each inode 902cdf01dd5SLinus Torvalds * write can dirty pagecache in the underlying blockdev. 903cdf01dd5SLinus Torvalds */ 904cdf01dd5SLinus Torvalds static unsigned long get_nr_dirty_pages(void) 905cdf01dd5SLinus Torvalds { 906cdf01dd5SLinus Torvalds return global_page_state(NR_FILE_DIRTY) + 907cdf01dd5SLinus Torvalds global_page_state(NR_UNSTABLE_NFS) + 908cdf01dd5SLinus Torvalds get_nr_dirty_inodes(); 909cdf01dd5SLinus Torvalds } 910cdf01dd5SLinus Torvalds 9116585027aSJan Kara static long wb_check_background_flush(struct bdi_writeback *wb) 9126585027aSJan Kara { 913b00949aaSWu Fengguang if (over_bground_thresh(wb->bdi)) { 9146585027aSJan Kara 9156585027aSJan Kara struct wb_writeback_work work = { 9166585027aSJan Kara .nr_pages = LONG_MAX, 9176585027aSJan Kara .sync_mode = WB_SYNC_NONE, 9186585027aSJan Kara .for_background = 1, 9196585027aSJan Kara .range_cyclic = 1, 9200e175a18SCurt Wohlgemuth .reason = WB_REASON_BACKGROUND, 9216585027aSJan Kara }; 9226585027aSJan Kara 9236585027aSJan Kara return wb_writeback(wb, &work); 9246585027aSJan Kara } 9256585027aSJan Kara 9266585027aSJan Kara return 0; 9276585027aSJan Kara } 9286585027aSJan Kara 92903ba3782SJens Axboe static long wb_check_old_data_flush(struct bdi_writeback *wb) 93003ba3782SJens Axboe { 93103ba3782SJens Axboe unsigned long expired; 93203ba3782SJens Axboe long nr_pages; 93303ba3782SJens Axboe 93469b62d01SJens Axboe /* 93569b62d01SJens Axboe * When set to zero, disable periodic writeback 93669b62d01SJens Axboe */ 93769b62d01SJens Axboe if (!dirty_writeback_interval) 93869b62d01SJens Axboe return 0; 93969b62d01SJens Axboe 94003ba3782SJens Axboe expired = wb->last_old_flush + 94103ba3782SJens Axboe msecs_to_jiffies(dirty_writeback_interval * 10); 94203ba3782SJens Axboe if (time_before(jiffies, expired)) 94303ba3782SJens Axboe return 0; 94403ba3782SJens Axboe 94503ba3782SJens Axboe wb->last_old_flush = jiffies; 946cdf01dd5SLinus Torvalds nr_pages = get_nr_dirty_pages(); 94703ba3782SJens Axboe 948c4a77a6cSJens Axboe if (nr_pages) { 94983ba7b07SChristoph Hellwig struct wb_writeback_work work = { 950c4a77a6cSJens Axboe .nr_pages = nr_pages, 951c4a77a6cSJens Axboe .sync_mode = WB_SYNC_NONE, 952c4a77a6cSJens Axboe .for_kupdate = 1, 953c4a77a6cSJens Axboe .range_cyclic = 1, 9540e175a18SCurt Wohlgemuth .reason = WB_REASON_PERIODIC, 955c4a77a6cSJens Axboe }; 956c4a77a6cSJens Axboe 95783ba7b07SChristoph Hellwig return wb_writeback(wb, &work); 958c4a77a6cSJens Axboe } 95903ba3782SJens Axboe 96003ba3782SJens Axboe return 0; 96103ba3782SJens Axboe } 96203ba3782SJens Axboe 96303ba3782SJens Axboe /* 96403ba3782SJens Axboe * Retrieve work items and do the writeback they describe 96503ba3782SJens Axboe */ 96625d130baSWanpeng Li static long wb_do_writeback(struct bdi_writeback *wb) 96703ba3782SJens Axboe { 96803ba3782SJens Axboe struct backing_dev_info *bdi = wb->bdi; 96983ba7b07SChristoph Hellwig struct wb_writeback_work *work; 970c4a77a6cSJens Axboe long wrote = 0; 97103ba3782SJens Axboe 97281d73a32SJan Kara set_bit(BDI_writeback_running, &wb->bdi->state); 97308852b6dSMinchan Kim while ((work = get_next_work_item(bdi)) != NULL) { 97483ba7b07SChristoph Hellwig 975455b2864SDave Chinner trace_writeback_exec(bdi, work); 976455b2864SDave Chinner 97783ba7b07SChristoph Hellwig wrote += wb_writeback(wb, work); 97803ba3782SJens Axboe 97903ba3782SJens Axboe /* 98083ba7b07SChristoph Hellwig * Notify the caller of completion if this is a synchronous 98183ba7b07SChristoph Hellwig * work item, otherwise just free it. 98203ba3782SJens Axboe */ 98383ba7b07SChristoph Hellwig if (work->done) 98483ba7b07SChristoph Hellwig complete(work->done); 98583ba7b07SChristoph Hellwig else 98683ba7b07SChristoph Hellwig kfree(work); 98703ba3782SJens Axboe } 98803ba3782SJens Axboe 98903ba3782SJens Axboe /* 99003ba3782SJens Axboe * Check for periodic writeback, kupdated() style 99103ba3782SJens Axboe */ 99203ba3782SJens Axboe wrote += wb_check_old_data_flush(wb); 9936585027aSJan Kara wrote += wb_check_background_flush(wb); 99481d73a32SJan Kara clear_bit(BDI_writeback_running, &wb->bdi->state); 99503ba3782SJens Axboe 99603ba3782SJens Axboe return wrote; 99703ba3782SJens Axboe } 99803ba3782SJens Axboe 99903ba3782SJens Axboe /* 100003ba3782SJens Axboe * Handle writeback of dirty data for the device backed by this bdi. Also 1001839a8e86STejun Heo * reschedules periodically and does kupdated style flushing. 100203ba3782SJens Axboe */ 1003839a8e86STejun Heo void bdi_writeback_workfn(struct work_struct *work) 100403ba3782SJens Axboe { 1005839a8e86STejun Heo struct bdi_writeback *wb = container_of(to_delayed_work(work), 1006839a8e86STejun Heo struct bdi_writeback, dwork); 100708243900SChristoph Hellwig struct backing_dev_info *bdi = wb->bdi; 100803ba3782SJens Axboe long pages_written; 100903ba3782SJens Axboe 1010ef3b1019STejun Heo set_worker_desc("flush-%s", dev_name(bdi->dev)); 1011766f9164SPeter Zijlstra current->flags |= PF_SWAPWRITE; 101203ba3782SJens Axboe 1013839a8e86STejun Heo if (likely(!current_is_workqueue_rescuer() || 1014839a8e86STejun Heo list_empty(&bdi->bdi_list))) { 101503ba3782SJens Axboe /* 1016839a8e86STejun Heo * The normal path. Keep writing back @bdi until its 1017839a8e86STejun Heo * work_list is empty. Note that this path is also taken 1018839a8e86STejun Heo * if @bdi is shutting down even when we're running off the 1019839a8e86STejun Heo * rescuer as work_list needs to be drained. 102003ba3782SJens Axboe */ 1021839a8e86STejun Heo do { 102225d130baSWanpeng Li pages_written = wb_do_writeback(wb); 1023455b2864SDave Chinner trace_writeback_pages_written(pages_written); 1024839a8e86STejun Heo } while (!list_empty(&bdi->work_list)); 1025839a8e86STejun Heo } else { 1026253c34e9SArtem Bityutskiy /* 1027839a8e86STejun Heo * bdi_wq can't get enough workers and we're running off 1028839a8e86STejun Heo * the emergency worker. Don't hog it. Hopefully, 1024 is 1029839a8e86STejun Heo * enough for efficient IO. 1030253c34e9SArtem Bityutskiy */ 1031839a8e86STejun Heo pages_written = writeback_inodes_wb(&bdi->wb, 1024, 1032839a8e86STejun Heo WB_REASON_FORKER_THREAD); 1033839a8e86STejun Heo trace_writeback_pages_written(pages_written); 103403ba3782SJens Axboe } 103503ba3782SJens Axboe 1036839a8e86STejun Heo if (!list_empty(&bdi->work_list) || 1037839a8e86STejun Heo (wb_has_dirty_io(wb) && dirty_writeback_interval)) 1038839a8e86STejun Heo queue_delayed_work(bdi_wq, &wb->dwork, 1039839a8e86STejun Heo msecs_to_jiffies(dirty_writeback_interval * 10)); 1040455b2864SDave Chinner 1041839a8e86STejun Heo current->flags &= ~PF_SWAPWRITE; 104203ba3782SJens Axboe } 104303ba3782SJens Axboe 104403ba3782SJens Axboe /* 104503ba3782SJens Axboe * Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back 104603ba3782SJens Axboe * the whole world. 104703ba3782SJens Axboe */ 10480e175a18SCurt Wohlgemuth void wakeup_flusher_threads(long nr_pages, enum wb_reason reason) 104903ba3782SJens Axboe { 1050b8c2f347SChristoph Hellwig struct backing_dev_info *bdi; 1051b8c2f347SChristoph Hellwig 105283ba7b07SChristoph Hellwig if (!nr_pages) { 105383ba7b07SChristoph Hellwig nr_pages = global_page_state(NR_FILE_DIRTY) + 105403ba3782SJens Axboe global_page_state(NR_UNSTABLE_NFS); 1055b8c2f347SChristoph Hellwig } 1056b8c2f347SChristoph Hellwig 1057b8c2f347SChristoph Hellwig rcu_read_lock(); 1058b8c2f347SChristoph Hellwig list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { 1059b8c2f347SChristoph Hellwig if (!bdi_has_dirty_io(bdi)) 1060b8c2f347SChristoph Hellwig continue; 10610e175a18SCurt Wohlgemuth __bdi_start_writeback(bdi, nr_pages, false, reason); 1062b8c2f347SChristoph Hellwig } 1063b8c2f347SChristoph Hellwig rcu_read_unlock(); 106403ba3782SJens Axboe } 106503ba3782SJens Axboe 106603ba3782SJens Axboe static noinline void block_dump___mark_inode_dirty(struct inode *inode) 106703ba3782SJens Axboe { 106803ba3782SJens Axboe if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { 106903ba3782SJens Axboe struct dentry *dentry; 107003ba3782SJens Axboe const char *name = "?"; 107103ba3782SJens Axboe 107203ba3782SJens Axboe dentry = d_find_alias(inode); 107303ba3782SJens Axboe if (dentry) { 107403ba3782SJens Axboe spin_lock(&dentry->d_lock); 107503ba3782SJens Axboe name = (const char *) dentry->d_name.name; 107603ba3782SJens Axboe } 107703ba3782SJens Axboe printk(KERN_DEBUG 107803ba3782SJens Axboe "%s(%d): dirtied inode %lu (%s) on %s\n", 107903ba3782SJens Axboe current->comm, task_pid_nr(current), inode->i_ino, 108003ba3782SJens Axboe name, inode->i_sb->s_id); 108103ba3782SJens Axboe if (dentry) { 108203ba3782SJens Axboe spin_unlock(&dentry->d_lock); 108303ba3782SJens Axboe dput(dentry); 108403ba3782SJens Axboe } 108503ba3782SJens Axboe } 108603ba3782SJens Axboe } 108703ba3782SJens Axboe 108803ba3782SJens Axboe /** 108903ba3782SJens Axboe * __mark_inode_dirty - internal function 109003ba3782SJens Axboe * @inode: inode to mark 109103ba3782SJens Axboe * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) 109203ba3782SJens Axboe * Mark an inode as dirty. Callers should use mark_inode_dirty or 109303ba3782SJens Axboe * mark_inode_dirty_sync. 109403ba3782SJens Axboe * 109503ba3782SJens Axboe * Put the inode on the super block's dirty list. 109603ba3782SJens Axboe * 109703ba3782SJens Axboe * CAREFUL! We mark it dirty unconditionally, but move it onto the 109803ba3782SJens Axboe * dirty list only if it is hashed or if it refers to a blockdev. 109903ba3782SJens Axboe * If it was not hashed, it will never be added to the dirty list 110003ba3782SJens Axboe * even if it is later hashed, as it will have been marked dirty already. 110103ba3782SJens Axboe * 110203ba3782SJens Axboe * In short, make sure you hash any inodes _before_ you start marking 110303ba3782SJens Axboe * them dirty. 110403ba3782SJens Axboe * 110503ba3782SJens Axboe * Note that for blockdevs, inode->dirtied_when represents the dirtying time of 110603ba3782SJens Axboe * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of 110703ba3782SJens Axboe * the kernel-internal blockdev inode represents the dirtying time of the 110803ba3782SJens Axboe * blockdev's pages. This is why for I_DIRTY_PAGES we always use 110903ba3782SJens Axboe * page->mapping->host, so the page-dirtying time is recorded in the internal 111003ba3782SJens Axboe * blockdev inode. 111103ba3782SJens Axboe */ 111203ba3782SJens Axboe void __mark_inode_dirty(struct inode *inode, int flags) 111303ba3782SJens Axboe { 111403ba3782SJens Axboe struct super_block *sb = inode->i_sb; 1115253c34e9SArtem Bityutskiy struct backing_dev_info *bdi = NULL; 111603ba3782SJens Axboe 111703ba3782SJens Axboe /* 111803ba3782SJens Axboe * Don't do this for I_DIRTY_PAGES - that doesn't actually 111903ba3782SJens Axboe * dirty the inode itself 112003ba3782SJens Axboe */ 112103ba3782SJens Axboe if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { 11229fb0a7daSTejun Heo trace_writeback_dirty_inode_start(inode, flags); 11239fb0a7daSTejun Heo 112403ba3782SJens Axboe if (sb->s_op->dirty_inode) 1125aa385729SChristoph Hellwig sb->s_op->dirty_inode(inode, flags); 11269fb0a7daSTejun Heo 11279fb0a7daSTejun Heo trace_writeback_dirty_inode(inode, flags); 112803ba3782SJens Axboe } 112903ba3782SJens Axboe 113003ba3782SJens Axboe /* 113103ba3782SJens Axboe * make sure that changes are seen by all cpus before we test i_state 113203ba3782SJens Axboe * -- mikulas 113303ba3782SJens Axboe */ 113403ba3782SJens Axboe smp_mb(); 113503ba3782SJens Axboe 113603ba3782SJens Axboe /* avoid the locking if we can */ 113703ba3782SJens Axboe if ((inode->i_state & flags) == flags) 113803ba3782SJens Axboe return; 113903ba3782SJens Axboe 114003ba3782SJens Axboe if (unlikely(block_dump)) 114103ba3782SJens Axboe block_dump___mark_inode_dirty(inode); 114203ba3782SJens Axboe 1143250df6edSDave Chinner spin_lock(&inode->i_lock); 114403ba3782SJens Axboe if ((inode->i_state & flags) != flags) { 114503ba3782SJens Axboe const int was_dirty = inode->i_state & I_DIRTY; 114603ba3782SJens Axboe 114703ba3782SJens Axboe inode->i_state |= flags; 114803ba3782SJens Axboe 114903ba3782SJens Axboe /* 115003ba3782SJens Axboe * If the inode is being synced, just update its dirty state. 115103ba3782SJens Axboe * The unlocker will place the inode on the appropriate 115203ba3782SJens Axboe * superblock list, based upon its state. 115303ba3782SJens Axboe */ 115403ba3782SJens Axboe if (inode->i_state & I_SYNC) 1155250df6edSDave Chinner goto out_unlock_inode; 115603ba3782SJens Axboe 115703ba3782SJens Axboe /* 115803ba3782SJens Axboe * Only add valid (hashed) inodes to the superblock's 115903ba3782SJens Axboe * dirty list. Add blockdev inodes as well. 116003ba3782SJens Axboe */ 116103ba3782SJens Axboe if (!S_ISBLK(inode->i_mode)) { 11621d3382cbSAl Viro if (inode_unhashed(inode)) 1163250df6edSDave Chinner goto out_unlock_inode; 116403ba3782SJens Axboe } 1165a4ffdde6SAl Viro if (inode->i_state & I_FREEING) 1166250df6edSDave Chinner goto out_unlock_inode; 116703ba3782SJens Axboe 116803ba3782SJens Axboe /* 116903ba3782SJens Axboe * If the inode was already on b_dirty/b_io/b_more_io, don't 117003ba3782SJens Axboe * reposition it (that would break b_dirty time-ordering). 117103ba3782SJens Axboe */ 117203ba3782SJens Axboe if (!was_dirty) { 1173a66979abSDave Chinner bool wakeup_bdi = false; 1174253c34e9SArtem Bityutskiy bdi = inode_to_bdi(inode); 1175500b067cSJens Axboe 1176253c34e9SArtem Bityutskiy if (bdi_cap_writeback_dirty(bdi)) { 1177253c34e9SArtem Bityutskiy WARN(!test_bit(BDI_registered, &bdi->state), 1178253c34e9SArtem Bityutskiy "bdi-%s not registered\n", bdi->name); 1179253c34e9SArtem Bityutskiy 1180253c34e9SArtem Bityutskiy /* 1181253c34e9SArtem Bityutskiy * If this is the first dirty inode for this 1182253c34e9SArtem Bityutskiy * bdi, we have to wake-up the corresponding 1183253c34e9SArtem Bityutskiy * bdi thread to make sure background 1184253c34e9SArtem Bityutskiy * write-back happens later. 1185253c34e9SArtem Bityutskiy */ 1186253c34e9SArtem Bityutskiy if (!wb_has_dirty_io(&bdi->wb)) 1187253c34e9SArtem Bityutskiy wakeup_bdi = true; 1188500b067cSJens Axboe } 118903ba3782SJens Axboe 1190a66979abSDave Chinner spin_unlock(&inode->i_lock); 1191f758eeabSChristoph Hellwig spin_lock(&bdi->wb.list_lock); 119203ba3782SJens Axboe inode->dirtied_when = jiffies; 11937ccf19a8SNick Piggin list_move(&inode->i_wb_list, &bdi->wb.b_dirty); 1194f758eeabSChristoph Hellwig spin_unlock(&bdi->wb.list_lock); 1195253c34e9SArtem Bityutskiy 1196253c34e9SArtem Bityutskiy if (wakeup_bdi) 11976467716aSArtem Bityutskiy bdi_wakeup_thread_delayed(bdi); 1198a66979abSDave Chinner return; 1199a66979abSDave Chinner } 1200a66979abSDave Chinner } 1201a66979abSDave Chinner out_unlock_inode: 1202a66979abSDave Chinner spin_unlock(&inode->i_lock); 1203a66979abSDave Chinner 120403ba3782SJens Axboe } 120503ba3782SJens Axboe EXPORT_SYMBOL(__mark_inode_dirty); 120603ba3782SJens Axboe 1207b6e51316SJens Axboe static void wait_sb_inodes(struct super_block *sb) 120866f3b8e2SJens Axboe { 120938f21977SNick Piggin struct inode *inode, *old_inode = NULL; 121038f21977SNick Piggin 121103ba3782SJens Axboe /* 121203ba3782SJens Axboe * We need to be protected against the filesystem going from 121303ba3782SJens Axboe * r/o to r/w or vice versa. 121403ba3782SJens Axboe */ 1215b6e51316SJens Axboe WARN_ON(!rwsem_is_locked(&sb->s_umount)); 121603ba3782SJens Axboe 121755fa6091SDave Chinner spin_lock(&inode_sb_list_lock); 121866f3b8e2SJens Axboe 121938f21977SNick Piggin /* 122038f21977SNick Piggin * Data integrity sync. Must wait for all pages under writeback, 122138f21977SNick Piggin * because there may have been pages dirtied before our sync 122238f21977SNick Piggin * call, but which had writeout started before we write it out. 122338f21977SNick Piggin * In which case, the inode may not be on the dirty list, but 122438f21977SNick Piggin * we still have to wait for that writeout. 122538f21977SNick Piggin */ 1226b6e51316SJens Axboe list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { 1227250df6edSDave Chinner struct address_space *mapping = inode->i_mapping; 122838f21977SNick Piggin 1229250df6edSDave Chinner spin_lock(&inode->i_lock); 1230250df6edSDave Chinner if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) || 1231250df6edSDave Chinner (mapping->nrpages == 0)) { 1232250df6edSDave Chinner spin_unlock(&inode->i_lock); 123338f21977SNick Piggin continue; 1234250df6edSDave Chinner } 123538f21977SNick Piggin __iget(inode); 1236250df6edSDave Chinner spin_unlock(&inode->i_lock); 123755fa6091SDave Chinner spin_unlock(&inode_sb_list_lock); 123855fa6091SDave Chinner 123938f21977SNick Piggin /* 124055fa6091SDave Chinner * We hold a reference to 'inode' so it couldn't have been 124155fa6091SDave Chinner * removed from s_inodes list while we dropped the 124255fa6091SDave Chinner * inode_sb_list_lock. We cannot iput the inode now as we can 124355fa6091SDave Chinner * be holding the last reference and we cannot iput it under 124455fa6091SDave Chinner * inode_sb_list_lock. So we keep the reference and iput it 124555fa6091SDave Chinner * later. 124638f21977SNick Piggin */ 124738f21977SNick Piggin iput(old_inode); 124838f21977SNick Piggin old_inode = inode; 124938f21977SNick Piggin 125038f21977SNick Piggin filemap_fdatawait(mapping); 125138f21977SNick Piggin 125238f21977SNick Piggin cond_resched(); 125338f21977SNick Piggin 125455fa6091SDave Chinner spin_lock(&inode_sb_list_lock); 125538f21977SNick Piggin } 125655fa6091SDave Chinner spin_unlock(&inode_sb_list_lock); 125738f21977SNick Piggin iput(old_inode); 125866f3b8e2SJens Axboe } 12591da177e4SLinus Torvalds 1260d8a8559cSJens Axboe /** 12613259f8beSChris Mason * writeback_inodes_sb_nr - writeback dirty inodes from given super_block 1262d8a8559cSJens Axboe * @sb: the superblock 12633259f8beSChris Mason * @nr: the number of pages to write 1264786228abSMarcos Paulo de Souza * @reason: reason why some writeback work initiated 12651da177e4SLinus Torvalds * 1266d8a8559cSJens Axboe * Start writeback on some inodes on this super_block. No guarantees are made 1267d8a8559cSJens Axboe * on how many (if any) will be written, and this function does not wait 12683259f8beSChris Mason * for IO completion of submitted IO. 12691da177e4SLinus Torvalds */ 12700e175a18SCurt Wohlgemuth void writeback_inodes_sb_nr(struct super_block *sb, 12710e175a18SCurt Wohlgemuth unsigned long nr, 12720e175a18SCurt Wohlgemuth enum wb_reason reason) 12731da177e4SLinus Torvalds { 127483ba7b07SChristoph Hellwig DECLARE_COMPLETION_ONSTACK(done); 127583ba7b07SChristoph Hellwig struct wb_writeback_work work = { 12763c4d7165SChristoph Hellwig .sb = sb, 12773c4d7165SChristoph Hellwig .sync_mode = WB_SYNC_NONE, 12786e6938b6SWu Fengguang .tagged_writepages = 1, 127983ba7b07SChristoph Hellwig .done = &done, 12803259f8beSChris Mason .nr_pages = nr, 12810e175a18SCurt Wohlgemuth .reason = reason, 12823c4d7165SChristoph Hellwig }; 12830e3c9a22SJens Axboe 12846eedc701SJan Kara if (sb->s_bdi == &noop_backing_dev_info) 12856eedc701SJan Kara return; 1286cf37e972SChristoph Hellwig WARN_ON(!rwsem_is_locked(&sb->s_umount)); 128783ba7b07SChristoph Hellwig bdi_queue_work(sb->s_bdi, &work); 128883ba7b07SChristoph Hellwig wait_for_completion(&done); 12891da177e4SLinus Torvalds } 12903259f8beSChris Mason EXPORT_SYMBOL(writeback_inodes_sb_nr); 12913259f8beSChris Mason 12923259f8beSChris Mason /** 12933259f8beSChris Mason * writeback_inodes_sb - writeback dirty inodes from given super_block 12943259f8beSChris Mason * @sb: the superblock 1295786228abSMarcos Paulo de Souza * @reason: reason why some writeback work was initiated 12963259f8beSChris Mason * 12973259f8beSChris Mason * Start writeback on some inodes on this super_block. No guarantees are made 12983259f8beSChris Mason * on how many (if any) will be written, and this function does not wait 12993259f8beSChris Mason * for IO completion of submitted IO. 13003259f8beSChris Mason */ 13010e175a18SCurt Wohlgemuth void writeback_inodes_sb(struct super_block *sb, enum wb_reason reason) 13023259f8beSChris Mason { 13030e175a18SCurt Wohlgemuth return writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason); 13043259f8beSChris Mason } 1305d8a8559cSJens Axboe EXPORT_SYMBOL(writeback_inodes_sb); 1306d8a8559cSJens Axboe 1307d8a8559cSJens Axboe /** 130810ee27a0SMiao Xie * try_to_writeback_inodes_sb_nr - try to start writeback if none underway 13093259f8beSChris Mason * @sb: the superblock 13103259f8beSChris Mason * @nr: the number of pages to write 131110ee27a0SMiao Xie * @reason: the reason of writeback 13123259f8beSChris Mason * 131310ee27a0SMiao Xie * Invoke writeback_inodes_sb_nr if no writeback is currently underway. 13143259f8beSChris Mason * Returns 1 if writeback was started, 0 if not. 13153259f8beSChris Mason */ 131610ee27a0SMiao Xie int try_to_writeback_inodes_sb_nr(struct super_block *sb, 13170e175a18SCurt Wohlgemuth unsigned long nr, 13180e175a18SCurt Wohlgemuth enum wb_reason reason) 13193259f8beSChris Mason { 132010ee27a0SMiao Xie if (writeback_in_progress(sb->s_bdi)) 132110ee27a0SMiao Xie return 1; 132210ee27a0SMiao Xie 132310ee27a0SMiao Xie if (!down_read_trylock(&sb->s_umount)) 132410ee27a0SMiao Xie return 0; 132510ee27a0SMiao Xie 13260e175a18SCurt Wohlgemuth writeback_inodes_sb_nr(sb, nr, reason); 13273259f8beSChris Mason up_read(&sb->s_umount); 13283259f8beSChris Mason return 1; 13293259f8beSChris Mason } 133010ee27a0SMiao Xie EXPORT_SYMBOL(try_to_writeback_inodes_sb_nr); 133110ee27a0SMiao Xie 133210ee27a0SMiao Xie /** 133310ee27a0SMiao Xie * try_to_writeback_inodes_sb - try to start writeback if none underway 133410ee27a0SMiao Xie * @sb: the superblock 133510ee27a0SMiao Xie * @reason: reason why some writeback work was initiated 133610ee27a0SMiao Xie * 133710ee27a0SMiao Xie * Implement by try_to_writeback_inodes_sb_nr() 133810ee27a0SMiao Xie * Returns 1 if writeback was started, 0 if not. 133910ee27a0SMiao Xie */ 134010ee27a0SMiao Xie int try_to_writeback_inodes_sb(struct super_block *sb, enum wb_reason reason) 134110ee27a0SMiao Xie { 134210ee27a0SMiao Xie return try_to_writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason); 134310ee27a0SMiao Xie } 134410ee27a0SMiao Xie EXPORT_SYMBOL(try_to_writeback_inodes_sb); 13453259f8beSChris Mason 13463259f8beSChris Mason /** 1347d8a8559cSJens Axboe * sync_inodes_sb - sync sb inode pages 1348d8a8559cSJens Axboe * @sb: the superblock 1349d8a8559cSJens Axboe * 1350d8a8559cSJens Axboe * This function writes and waits on any dirty inode belonging to this 1351cb9ef8d5SStefan Hajnoczi * super_block. 1352d8a8559cSJens Axboe */ 1353b6e51316SJens Axboe void sync_inodes_sb(struct super_block *sb) 1354d8a8559cSJens Axboe { 135583ba7b07SChristoph Hellwig DECLARE_COMPLETION_ONSTACK(done); 135683ba7b07SChristoph Hellwig struct wb_writeback_work work = { 13573c4d7165SChristoph Hellwig .sb = sb, 13583c4d7165SChristoph Hellwig .sync_mode = WB_SYNC_ALL, 13593c4d7165SChristoph Hellwig .nr_pages = LONG_MAX, 13603c4d7165SChristoph Hellwig .range_cyclic = 0, 136183ba7b07SChristoph Hellwig .done = &done, 13620e175a18SCurt Wohlgemuth .reason = WB_REASON_SYNC, 13637747bd4bSDave Chinner .for_sync = 1, 13643c4d7165SChristoph Hellwig }; 13653c4d7165SChristoph Hellwig 13666eedc701SJan Kara /* Nothing to do? */ 13676eedc701SJan Kara if (sb->s_bdi == &noop_backing_dev_info) 13686eedc701SJan Kara return; 1369cf37e972SChristoph Hellwig WARN_ON(!rwsem_is_locked(&sb->s_umount)); 1370cf37e972SChristoph Hellwig 137183ba7b07SChristoph Hellwig bdi_queue_work(sb->s_bdi, &work); 137283ba7b07SChristoph Hellwig wait_for_completion(&done); 137383ba7b07SChristoph Hellwig 1374b6e51316SJens Axboe wait_sb_inodes(sb); 1375d8a8559cSJens Axboe } 1376d8a8559cSJens Axboe EXPORT_SYMBOL(sync_inodes_sb); 13771da177e4SLinus Torvalds 13781da177e4SLinus Torvalds /** 13791da177e4SLinus Torvalds * write_inode_now - write an inode to disk 13801da177e4SLinus Torvalds * @inode: inode to write to disk 13811da177e4SLinus Torvalds * @sync: whether the write should be synchronous or not 13821da177e4SLinus Torvalds * 13837f04c26dSAndrea Arcangeli * This function commits an inode to disk immediately if it is dirty. This is 13847f04c26dSAndrea Arcangeli * primarily needed by knfsd. 13857f04c26dSAndrea Arcangeli * 13867f04c26dSAndrea Arcangeli * The caller must either have a ref on the inode or must have set I_WILL_FREE. 13871da177e4SLinus Torvalds */ 13881da177e4SLinus Torvalds int write_inode_now(struct inode *inode, int sync) 13891da177e4SLinus Torvalds { 1390f758eeabSChristoph Hellwig struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; 13911da177e4SLinus Torvalds struct writeback_control wbc = { 13921da177e4SLinus Torvalds .nr_to_write = LONG_MAX, 139318914b18SMike Galbraith .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE, 1394111ebb6eSOGAWA Hirofumi .range_start = 0, 1395111ebb6eSOGAWA Hirofumi .range_end = LLONG_MAX, 13961da177e4SLinus Torvalds }; 13971da177e4SLinus Torvalds 13981da177e4SLinus Torvalds if (!mapping_cap_writeback_dirty(inode->i_mapping)) 139949364ce2SAndrew Morton wbc.nr_to_write = 0; 14001da177e4SLinus Torvalds 14011da177e4SLinus Torvalds might_sleep(); 14024f8ad655SJan Kara return writeback_single_inode(inode, wb, &wbc); 14031da177e4SLinus Torvalds } 14041da177e4SLinus Torvalds EXPORT_SYMBOL(write_inode_now); 14051da177e4SLinus Torvalds 14061da177e4SLinus Torvalds /** 14071da177e4SLinus Torvalds * sync_inode - write an inode and its pages to disk. 14081da177e4SLinus Torvalds * @inode: the inode to sync 14091da177e4SLinus Torvalds * @wbc: controls the writeback mode 14101da177e4SLinus Torvalds * 14111da177e4SLinus Torvalds * sync_inode() will write an inode and its pages to disk. It will also 14121da177e4SLinus Torvalds * correctly update the inode on its superblock's dirty inode lists and will 14131da177e4SLinus Torvalds * update inode->i_state. 14141da177e4SLinus Torvalds * 14151da177e4SLinus Torvalds * The caller must have a ref on the inode. 14161da177e4SLinus Torvalds */ 14171da177e4SLinus Torvalds int sync_inode(struct inode *inode, struct writeback_control *wbc) 14181da177e4SLinus Torvalds { 14194f8ad655SJan Kara return writeback_single_inode(inode, &inode_to_bdi(inode)->wb, wbc); 14201da177e4SLinus Torvalds } 14211da177e4SLinus Torvalds EXPORT_SYMBOL(sync_inode); 1422c3765016SChristoph Hellwig 1423c3765016SChristoph Hellwig /** 1424c691b9d9SAndrew Morton * sync_inode_metadata - write an inode to disk 1425c3765016SChristoph Hellwig * @inode: the inode to sync 1426c3765016SChristoph Hellwig * @wait: wait for I/O to complete. 1427c3765016SChristoph Hellwig * 1428c691b9d9SAndrew Morton * Write an inode to disk and adjust its dirty state after completion. 1429c3765016SChristoph Hellwig * 1430c3765016SChristoph Hellwig * Note: only writes the actual inode, no associated data or other metadata. 1431c3765016SChristoph Hellwig */ 1432c3765016SChristoph Hellwig int sync_inode_metadata(struct inode *inode, int wait) 1433c3765016SChristoph Hellwig { 1434c3765016SChristoph Hellwig struct writeback_control wbc = { 1435c3765016SChristoph Hellwig .sync_mode = wait ? WB_SYNC_ALL : WB_SYNC_NONE, 1436c3765016SChristoph Hellwig .nr_to_write = 0, /* metadata-only */ 1437c3765016SChristoph Hellwig }; 1438c3765016SChristoph Hellwig 1439c3765016SChristoph Hellwig return sync_inode(inode, &wbc); 1440c3765016SChristoph Hellwig } 1441c3765016SChristoph Hellwig EXPORT_SYMBOL(sync_inode_metadata); 1442