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> 17f5ff8422SJens Axboe #include <linux/module.h> 181da177e4SLinus Torvalds #include <linux/spinlock.h> 191da177e4SLinus Torvalds #include <linux/sched.h> 201da177e4SLinus Torvalds #include <linux/fs.h> 211da177e4SLinus Torvalds #include <linux/mm.h> 2203ba3782SJens Axboe #include <linux/kthread.h> 2303ba3782SJens Axboe #include <linux/freezer.h> 241da177e4SLinus Torvalds #include <linux/writeback.h> 251da177e4SLinus Torvalds #include <linux/blkdev.h> 261da177e4SLinus Torvalds #include <linux/backing-dev.h> 271da177e4SLinus Torvalds #include <linux/buffer_head.h> 2807f3f05cSDavid Howells #include "internal.h" 291da177e4SLinus Torvalds 3066f3b8e2SJens Axboe #define inode_to_bdi(inode) ((inode)->i_mapping->backing_dev_info) 31f11b00f3SAdrian Bunk 3203ba3782SJens Axboe /* 33d0bceac7SJens Axboe * We don't actually have pdflush, but this one is exported though /proc... 34d0bceac7SJens Axboe */ 35d0bceac7SJens Axboe int nr_pdflush_threads; 36d0bceac7SJens Axboe 37d0bceac7SJens Axboe /* 38c4a77a6cSJens Axboe * Passed into wb_writeback(), essentially a subset of writeback_control 39c4a77a6cSJens Axboe */ 40c4a77a6cSJens Axboe struct wb_writeback_args { 41c4a77a6cSJens Axboe long nr_pages; 42c4a77a6cSJens Axboe struct super_block *sb; 43c4a77a6cSJens Axboe enum writeback_sync_modes sync_mode; 44c4a77a6cSJens Axboe int for_kupdate; 45c4a77a6cSJens Axboe int range_cyclic; 46c4a77a6cSJens Axboe }; 47c4a77a6cSJens Axboe 48c4a77a6cSJens Axboe /* 4903ba3782SJens Axboe * Work items for the bdi_writeback threads 50f11b00f3SAdrian Bunk */ 5103ba3782SJens Axboe struct bdi_work { 5203ba3782SJens Axboe struct list_head list; 5303ba3782SJens Axboe struct rcu_head rcu_head; 5403ba3782SJens Axboe 5503ba3782SJens Axboe unsigned long seen; 5603ba3782SJens Axboe atomic_t pending; 5703ba3782SJens Axboe 58c4a77a6cSJens Axboe struct wb_writeback_args args; 5903ba3782SJens Axboe 6003ba3782SJens Axboe unsigned long state; 6103ba3782SJens Axboe }; 6203ba3782SJens Axboe 6303ba3782SJens Axboe enum { 6403ba3782SJens Axboe WS_USED_B = 0, 6503ba3782SJens Axboe WS_ONSTACK_B, 6603ba3782SJens Axboe }; 6703ba3782SJens Axboe 6803ba3782SJens Axboe #define WS_USED (1 << WS_USED_B) 6903ba3782SJens Axboe #define WS_ONSTACK (1 << WS_ONSTACK_B) 7003ba3782SJens Axboe 7103ba3782SJens Axboe static inline bool bdi_work_on_stack(struct bdi_work *work) 72f11b00f3SAdrian Bunk { 7303ba3782SJens Axboe return test_bit(WS_ONSTACK_B, &work->state); 7403ba3782SJens Axboe } 7503ba3782SJens Axboe 7603ba3782SJens Axboe static inline void bdi_work_init(struct bdi_work *work, 7703ba3782SJens Axboe struct writeback_control *wbc) 7803ba3782SJens Axboe { 7903ba3782SJens Axboe INIT_RCU_HEAD(&work->rcu_head); 80c4a77a6cSJens Axboe work->args.sb = wbc->sb; 81c4a77a6cSJens Axboe work->args.nr_pages = wbc->nr_to_write; 82c4a77a6cSJens Axboe work->args.sync_mode = wbc->sync_mode; 83c4a77a6cSJens Axboe work->args.range_cyclic = wbc->range_cyclic; 84c4a77a6cSJens Axboe work->args.for_kupdate = 0; 8503ba3782SJens Axboe work->state = WS_USED; 8603ba3782SJens Axboe } 8703ba3782SJens Axboe 88f11b00f3SAdrian Bunk /** 89f11b00f3SAdrian Bunk * writeback_in_progress - determine whether there is writeback in progress 90f11b00f3SAdrian Bunk * @bdi: the device's backing_dev_info structure. 91f11b00f3SAdrian Bunk * 9203ba3782SJens Axboe * Determine whether there is writeback waiting to be handled against a 9303ba3782SJens Axboe * backing device. 94f11b00f3SAdrian Bunk */ 95f11b00f3SAdrian Bunk int writeback_in_progress(struct backing_dev_info *bdi) 96f11b00f3SAdrian Bunk { 9703ba3782SJens Axboe return !list_empty(&bdi->work_list); 98f11b00f3SAdrian Bunk } 99f11b00f3SAdrian Bunk 10003ba3782SJens Axboe static void bdi_work_clear(struct bdi_work *work) 101f11b00f3SAdrian Bunk { 10203ba3782SJens Axboe clear_bit(WS_USED_B, &work->state); 10303ba3782SJens Axboe smp_mb__after_clear_bit(); 10403ba3782SJens Axboe wake_up_bit(&work->state, WS_USED_B); 105f11b00f3SAdrian Bunk } 106f11b00f3SAdrian Bunk 10703ba3782SJens Axboe static void bdi_work_free(struct rcu_head *head) 1084195f73dSNick Piggin { 10903ba3782SJens Axboe struct bdi_work *work = container_of(head, struct bdi_work, rcu_head); 1104195f73dSNick Piggin 11103ba3782SJens Axboe if (!bdi_work_on_stack(work)) 11203ba3782SJens Axboe kfree(work); 11303ba3782SJens Axboe else 11403ba3782SJens Axboe bdi_work_clear(work); 1154195f73dSNick Piggin } 1164195f73dSNick Piggin 11703ba3782SJens Axboe static void wb_work_complete(struct bdi_work *work) 1181da177e4SLinus Torvalds { 119c4a77a6cSJens Axboe const enum writeback_sync_modes sync_mode = work->args.sync_mode; 1201da177e4SLinus Torvalds 1211da177e4SLinus Torvalds /* 12203ba3782SJens Axboe * For allocated work, we can clear the done/seen bit right here. 12303ba3782SJens Axboe * For on-stack work, we need to postpone both the clear and free 12403ba3782SJens Axboe * to after the RCU grace period, since the stack could be invalidated 12503ba3782SJens Axboe * as soon as bdi_work_clear() has done the wakeup. 1261da177e4SLinus Torvalds */ 12703ba3782SJens Axboe if (!bdi_work_on_stack(work)) 12803ba3782SJens Axboe bdi_work_clear(work); 12903ba3782SJens Axboe if (sync_mode == WB_SYNC_NONE || bdi_work_on_stack(work)) 13003ba3782SJens Axboe call_rcu(&work->rcu_head, bdi_work_free); 1311da177e4SLinus Torvalds } 1321da177e4SLinus Torvalds 13303ba3782SJens Axboe static void wb_clear_pending(struct bdi_writeback *wb, struct bdi_work *work) 13403ba3782SJens Axboe { 1351da177e4SLinus Torvalds /* 13603ba3782SJens Axboe * The caller has retrieved the work arguments from this work, 13703ba3782SJens Axboe * drop our reference. If this is the last ref, delete and free it 13803ba3782SJens Axboe */ 13903ba3782SJens Axboe if (atomic_dec_and_test(&work->pending)) { 14003ba3782SJens Axboe struct backing_dev_info *bdi = wb->bdi; 14103ba3782SJens Axboe 14203ba3782SJens Axboe spin_lock(&bdi->wb_lock); 14303ba3782SJens Axboe list_del_rcu(&work->list); 14403ba3782SJens Axboe spin_unlock(&bdi->wb_lock); 14503ba3782SJens Axboe 14603ba3782SJens Axboe wb_work_complete(work); 14703ba3782SJens Axboe } 14803ba3782SJens Axboe } 14903ba3782SJens Axboe 15003ba3782SJens Axboe static void bdi_queue_work(struct backing_dev_info *bdi, struct bdi_work *work) 15103ba3782SJens Axboe { 15203ba3782SJens Axboe if (work) { 15303ba3782SJens Axboe work->seen = bdi->wb_mask; 15403ba3782SJens Axboe BUG_ON(!work->seen); 15503ba3782SJens Axboe atomic_set(&work->pending, bdi->wb_cnt); 15603ba3782SJens Axboe BUG_ON(!bdi->wb_cnt); 15703ba3782SJens Axboe 15803ba3782SJens Axboe /* 15903ba3782SJens Axboe * Make sure stores are seen before it appears on the list 1601da177e4SLinus Torvalds */ 1611da177e4SLinus Torvalds smp_mb(); 1621da177e4SLinus Torvalds 16303ba3782SJens Axboe spin_lock(&bdi->wb_lock); 16403ba3782SJens Axboe list_add_tail_rcu(&work->list, &bdi->work_list); 16503ba3782SJens Axboe spin_unlock(&bdi->wb_lock); 16603ba3782SJens Axboe } 1671da177e4SLinus Torvalds 1681da177e4SLinus Torvalds /* 16903ba3782SJens Axboe * If the default thread isn't there, make sure we add it. When 17003ba3782SJens Axboe * it gets created and wakes up, we'll run this work. 1711da177e4SLinus Torvalds */ 17203ba3782SJens Axboe if (unlikely(list_empty_careful(&bdi->wb_list))) 17303ba3782SJens Axboe wake_up_process(default_backing_dev_info.wb.task); 17403ba3782SJens Axboe else { 17503ba3782SJens Axboe struct bdi_writeback *wb = &bdi->wb; 1761da177e4SLinus Torvalds 1771da177e4SLinus Torvalds /* 17803ba3782SJens Axboe * If we failed allocating the bdi work item, wake up the wb 17903ba3782SJens Axboe * thread always. As a safety precaution, it'll flush out 18003ba3782SJens Axboe * everything 1811da177e4SLinus Torvalds */ 18203ba3782SJens Axboe if (!wb_has_dirty_io(wb)) { 18303ba3782SJens Axboe if (work) 18403ba3782SJens Axboe wb_clear_pending(wb, work); 18503ba3782SJens Axboe } else if (wb->task) 18603ba3782SJens Axboe wake_up_process(wb->task); 1871da177e4SLinus Torvalds } 18803ba3782SJens Axboe } 1891da177e4SLinus Torvalds 1901da177e4SLinus Torvalds /* 19103ba3782SJens Axboe * Used for on-stack allocated work items. The caller needs to wait until 19203ba3782SJens Axboe * the wb threads have acked the work before it's safe to continue. 1931da177e4SLinus Torvalds */ 19403ba3782SJens Axboe static void bdi_wait_on_work_clear(struct bdi_work *work) 1951da177e4SLinus Torvalds { 19603ba3782SJens Axboe wait_on_bit(&work->state, WS_USED_B, bdi_sched_wait, 19703ba3782SJens Axboe TASK_UNINTERRUPTIBLE); 19803ba3782SJens Axboe } 19903ba3782SJens Axboe 200f11fcae8SJens Axboe static void bdi_alloc_queue_work(struct backing_dev_info *bdi, 201f11fcae8SJens Axboe struct writeback_control *wbc) 20203ba3782SJens Axboe { 20303ba3782SJens Axboe struct bdi_work *work; 20403ba3782SJens Axboe 20503ba3782SJens Axboe work = kmalloc(sizeof(*work), GFP_ATOMIC); 20603ba3782SJens Axboe if (work) 20703ba3782SJens Axboe bdi_work_init(work, wbc); 20803ba3782SJens Axboe 209f11fcae8SJens Axboe bdi_queue_work(bdi, work); 21003ba3782SJens Axboe } 21103ba3782SJens Axboe 21203ba3782SJens Axboe void bdi_start_writeback(struct writeback_control *wbc) 21303ba3782SJens Axboe { 21403ba3782SJens Axboe /* 215f0fad8a5SChristoph Hellwig * WB_SYNC_NONE is opportunistic writeback. If this allocation fails, 216f0fad8a5SChristoph Hellwig * bdi_queue_work() will wake up the thread and flush old data. This 217f0fad8a5SChristoph Hellwig * should ensure some amount of progress in freeing memory. 21803ba3782SJens Axboe */ 219f11fcae8SJens Axboe if (wbc->sync_mode != WB_SYNC_ALL) 220f11fcae8SJens Axboe bdi_alloc_queue_work(wbc->bdi, wbc); 221f11fcae8SJens Axboe else { 222f0fad8a5SChristoph Hellwig struct bdi_work work; 223f0fad8a5SChristoph Hellwig 224f0fad8a5SChristoph Hellwig bdi_work_init(&work, wbc); 225f0fad8a5SChristoph Hellwig work.state |= WS_ONSTACK; 226f0fad8a5SChristoph Hellwig 227f0fad8a5SChristoph Hellwig bdi_queue_work(wbc->bdi, &work); 228f0fad8a5SChristoph Hellwig bdi_wait_on_work_clear(&work); 22903ba3782SJens Axboe } 2301da177e4SLinus Torvalds } 2311da177e4SLinus Torvalds 2321da177e4SLinus Torvalds /* 2336610a0bcSAndrew Morton * Redirty an inode: set its when-it-was dirtied timestamp and move it to the 2346610a0bcSAndrew Morton * furthest end of its superblock's dirty-inode list. 2356610a0bcSAndrew Morton * 2366610a0bcSAndrew Morton * Before stamping the inode's ->dirtied_when, we check to see whether it is 23766f3b8e2SJens Axboe * already the most-recently-dirtied inode on the b_dirty list. If that is 2386610a0bcSAndrew Morton * the case then the inode must have been redirtied while it was being written 2396610a0bcSAndrew Morton * out and we don't reset its dirtied_when. 2406610a0bcSAndrew Morton */ 2416610a0bcSAndrew Morton static void redirty_tail(struct inode *inode) 2426610a0bcSAndrew Morton { 24303ba3782SJens Axboe struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; 2446610a0bcSAndrew Morton 24503ba3782SJens Axboe if (!list_empty(&wb->b_dirty)) { 24666f3b8e2SJens Axboe struct inode *tail; 2476610a0bcSAndrew Morton 24803ba3782SJens Axboe tail = list_entry(wb->b_dirty.next, struct inode, i_list); 24966f3b8e2SJens Axboe if (time_before(inode->dirtied_when, tail->dirtied_when)) 2506610a0bcSAndrew Morton inode->dirtied_when = jiffies; 2516610a0bcSAndrew Morton } 25203ba3782SJens Axboe list_move(&inode->i_list, &wb->b_dirty); 2536610a0bcSAndrew Morton } 2546610a0bcSAndrew Morton 2556610a0bcSAndrew Morton /* 25666f3b8e2SJens Axboe * requeue inode for re-scanning after bdi->b_io list is exhausted. 257c986d1e2SAndrew Morton */ 2580e0f4fc2SKen Chen static void requeue_io(struct inode *inode) 259c986d1e2SAndrew Morton { 26003ba3782SJens Axboe struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; 26103ba3782SJens Axboe 26203ba3782SJens Axboe list_move(&inode->i_list, &wb->b_more_io); 263c986d1e2SAndrew Morton } 264c986d1e2SAndrew Morton 2651c0eeaf5SJoern Engel static void inode_sync_complete(struct inode *inode) 2661c0eeaf5SJoern Engel { 2671c0eeaf5SJoern Engel /* 2681c0eeaf5SJoern Engel * Prevent speculative execution through spin_unlock(&inode_lock); 2691c0eeaf5SJoern Engel */ 2701c0eeaf5SJoern Engel smp_mb(); 2711c0eeaf5SJoern Engel wake_up_bit(&inode->i_state, __I_SYNC); 2721c0eeaf5SJoern Engel } 2731c0eeaf5SJoern Engel 274d2caa3c5SJeff Layton static bool inode_dirtied_after(struct inode *inode, unsigned long t) 275d2caa3c5SJeff Layton { 276d2caa3c5SJeff Layton bool ret = time_after(inode->dirtied_when, t); 277d2caa3c5SJeff Layton #ifndef CONFIG_64BIT 278d2caa3c5SJeff Layton /* 279d2caa3c5SJeff Layton * For inodes being constantly redirtied, dirtied_when can get stuck. 280d2caa3c5SJeff Layton * It _appears_ to be in the future, but is actually in distant past. 281d2caa3c5SJeff Layton * This test is necessary to prevent such wrapped-around relative times 282d2caa3c5SJeff Layton * from permanently stopping the whole pdflush writeback. 283d2caa3c5SJeff Layton */ 284d2caa3c5SJeff Layton ret = ret && time_before_eq(inode->dirtied_when, jiffies); 285d2caa3c5SJeff Layton #endif 286d2caa3c5SJeff Layton return ret; 287d2caa3c5SJeff Layton } 288d2caa3c5SJeff Layton 289c986d1e2SAndrew Morton /* 2902c136579SFengguang Wu * Move expired dirty inodes from @delaying_queue to @dispatch_queue. 2912c136579SFengguang Wu */ 2922c136579SFengguang Wu static void move_expired_inodes(struct list_head *delaying_queue, 2932c136579SFengguang Wu struct list_head *dispatch_queue, 2942c136579SFengguang Wu unsigned long *older_than_this) 2952c136579SFengguang Wu { 2962c136579SFengguang Wu while (!list_empty(delaying_queue)) { 2972c136579SFengguang Wu struct inode *inode = list_entry(delaying_queue->prev, 2982c136579SFengguang Wu struct inode, i_list); 2992c136579SFengguang Wu if (older_than_this && 300d2caa3c5SJeff Layton inode_dirtied_after(inode, *older_than_this)) 3012c136579SFengguang Wu break; 3022c136579SFengguang Wu list_move(&inode->i_list, dispatch_queue); 3032c136579SFengguang Wu } 3042c136579SFengguang Wu } 3052c136579SFengguang Wu 3062c136579SFengguang Wu /* 3072c136579SFengguang Wu * Queue all expired dirty inodes for io, eldest first. 3082c136579SFengguang Wu */ 30903ba3782SJens Axboe static void queue_io(struct bdi_writeback *wb, unsigned long *older_than_this) 3102c136579SFengguang Wu { 31103ba3782SJens Axboe list_splice_init(&wb->b_more_io, wb->b_io.prev); 31203ba3782SJens Axboe move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this); 31366f3b8e2SJens Axboe } 31466f3b8e2SJens Axboe 31503ba3782SJens Axboe static int write_inode(struct inode *inode, int sync) 31666f3b8e2SJens Axboe { 31703ba3782SJens Axboe if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) 31803ba3782SJens Axboe return inode->i_sb->s_op->write_inode(inode, sync); 31903ba3782SJens Axboe return 0; 32066f3b8e2SJens Axboe } 32108d8e974SFengguang Wu 3222c136579SFengguang Wu /* 32301c03194SChristoph Hellwig * Wait for writeback on an inode to complete. 32401c03194SChristoph Hellwig */ 32501c03194SChristoph Hellwig static void inode_wait_for_writeback(struct inode *inode) 32601c03194SChristoph Hellwig { 32701c03194SChristoph Hellwig DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); 32801c03194SChristoph Hellwig wait_queue_head_t *wqh; 32901c03194SChristoph Hellwig 33001c03194SChristoph Hellwig wqh = bit_waitqueue(&inode->i_state, __I_SYNC); 33101c03194SChristoph Hellwig do { 33201c03194SChristoph Hellwig spin_unlock(&inode_lock); 33301c03194SChristoph Hellwig __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE); 33401c03194SChristoph Hellwig spin_lock(&inode_lock); 33501c03194SChristoph Hellwig } while (inode->i_state & I_SYNC); 33601c03194SChristoph Hellwig } 33701c03194SChristoph Hellwig 33801c03194SChristoph Hellwig /* 33901c03194SChristoph Hellwig * Write out an inode's dirty pages. Called under inode_lock. Either the 34001c03194SChristoph Hellwig * caller has ref on the inode (either via __iget or via syscall against an fd) 34101c03194SChristoph Hellwig * or the inode has I_WILL_FREE set (via generic_forget_inode) 34201c03194SChristoph Hellwig * 3431da177e4SLinus Torvalds * If `wait' is set, wait on the writeout. 3441da177e4SLinus Torvalds * 3451da177e4SLinus Torvalds * The whole writeout design is quite complex and fragile. We want to avoid 3461da177e4SLinus Torvalds * starvation of particular inodes when others are being redirtied, prevent 3471da177e4SLinus Torvalds * livelocks, etc. 3481da177e4SLinus Torvalds * 3491da177e4SLinus Torvalds * Called under inode_lock. 3501da177e4SLinus Torvalds */ 3511da177e4SLinus Torvalds static int 35201c03194SChristoph Hellwig writeback_single_inode(struct inode *inode, struct writeback_control *wbc) 3531da177e4SLinus Torvalds { 3541da177e4SLinus Torvalds struct address_space *mapping = inode->i_mapping; 3551da177e4SLinus Torvalds int wait = wbc->sync_mode == WB_SYNC_ALL; 35601c03194SChristoph Hellwig unsigned dirty; 3571da177e4SLinus Torvalds int ret; 3581da177e4SLinus Torvalds 35901c03194SChristoph Hellwig if (!atomic_read(&inode->i_count)) 36001c03194SChristoph Hellwig WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); 36101c03194SChristoph Hellwig else 36201c03194SChristoph Hellwig WARN_ON(inode->i_state & I_WILL_FREE); 36301c03194SChristoph Hellwig 36401c03194SChristoph Hellwig if (inode->i_state & I_SYNC) { 36501c03194SChristoph Hellwig /* 36601c03194SChristoph Hellwig * If this inode is locked for writeback and we are not doing 36766f3b8e2SJens Axboe * writeback-for-data-integrity, move it to b_more_io so that 36801c03194SChristoph Hellwig * writeback can proceed with the other inodes on s_io. 36901c03194SChristoph Hellwig * 37001c03194SChristoph Hellwig * We'll have another go at writing back this inode when we 37166f3b8e2SJens Axboe * completed a full scan of b_io. 37201c03194SChristoph Hellwig */ 37301c03194SChristoph Hellwig if (!wait) { 37401c03194SChristoph Hellwig requeue_io(inode); 37501c03194SChristoph Hellwig return 0; 37601c03194SChristoph Hellwig } 37701c03194SChristoph Hellwig 37801c03194SChristoph Hellwig /* 37901c03194SChristoph Hellwig * It's a data-integrity sync. We must wait. 38001c03194SChristoph Hellwig */ 38101c03194SChristoph Hellwig inode_wait_for_writeback(inode); 38201c03194SChristoph Hellwig } 38301c03194SChristoph Hellwig 3841c0eeaf5SJoern Engel BUG_ON(inode->i_state & I_SYNC); 3851da177e4SLinus Torvalds 3861c0eeaf5SJoern Engel /* Set I_SYNC, reset I_DIRTY */ 3871da177e4SLinus Torvalds dirty = inode->i_state & I_DIRTY; 3881c0eeaf5SJoern Engel inode->i_state |= I_SYNC; 3891da177e4SLinus Torvalds inode->i_state &= ~I_DIRTY; 3901da177e4SLinus Torvalds 3911da177e4SLinus Torvalds spin_unlock(&inode_lock); 3921da177e4SLinus Torvalds 3931da177e4SLinus Torvalds ret = do_writepages(mapping, wbc); 3941da177e4SLinus Torvalds 3951da177e4SLinus Torvalds /* Don't write the inode if only I_DIRTY_PAGES was set */ 3961da177e4SLinus Torvalds if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { 3971da177e4SLinus Torvalds int err = write_inode(inode, wait); 3981da177e4SLinus Torvalds if (ret == 0) 3991da177e4SLinus Torvalds ret = err; 4001da177e4SLinus Torvalds } 4011da177e4SLinus Torvalds 4021da177e4SLinus Torvalds if (wait) { 4031da177e4SLinus Torvalds int err = filemap_fdatawait(mapping); 4041da177e4SLinus Torvalds if (ret == 0) 4051da177e4SLinus Torvalds ret = err; 4061da177e4SLinus Torvalds } 4071da177e4SLinus Torvalds 4081da177e4SLinus Torvalds spin_lock(&inode_lock); 4091c0eeaf5SJoern Engel inode->i_state &= ~I_SYNC; 41084a89245SWu Fengguang if (!(inode->i_state & (I_FREEING | I_CLEAR))) { 4111da177e4SLinus Torvalds if (!(inode->i_state & I_DIRTY) && 4121da177e4SLinus Torvalds mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { 4131da177e4SLinus Torvalds /* 4141da177e4SLinus Torvalds * We didn't write back all the pages. nfs_writepages() 4151da177e4SLinus Torvalds * sometimes bales out without doing anything. Redirty 41666f3b8e2SJens Axboe * the inode; Move it from b_io onto b_more_io/b_dirty. 4171b43ef91SAndrew Morton */ 4181b43ef91SAndrew Morton /* 4191b43ef91SAndrew Morton * akpm: if the caller was the kupdate function we put 42066f3b8e2SJens Axboe * this inode at the head of b_dirty so it gets first 4211b43ef91SAndrew Morton * consideration. Otherwise, move it to the tail, for 4221b43ef91SAndrew Morton * the reasons described there. I'm not really sure 4231b43ef91SAndrew Morton * how much sense this makes. Presumably I had a good 4241b43ef91SAndrew Morton * reasons for doing it this way, and I'd rather not 4251b43ef91SAndrew Morton * muck with it at present. 4261da177e4SLinus Torvalds */ 4271da177e4SLinus Torvalds if (wbc->for_kupdate) { 4281da177e4SLinus Torvalds /* 4292c136579SFengguang Wu * For the kupdate function we move the inode 43066f3b8e2SJens Axboe * to b_more_io so it will get more writeout as 4312c136579SFengguang Wu * soon as the queue becomes uncongested. 4321da177e4SLinus Torvalds */ 4331da177e4SLinus Torvalds inode->i_state |= I_DIRTY_PAGES; 4348bc3be27SFengguang Wu if (wbc->nr_to_write <= 0) { 4358bc3be27SFengguang Wu /* 4368bc3be27SFengguang Wu * slice used up: queue for next turn 4378bc3be27SFengguang Wu */ 4380e0f4fc2SKen Chen requeue_io(inode); 4391da177e4SLinus Torvalds } else { 4401da177e4SLinus Torvalds /* 4418bc3be27SFengguang Wu * somehow blocked: retry later 4428bc3be27SFengguang Wu */ 4438bc3be27SFengguang Wu redirty_tail(inode); 4448bc3be27SFengguang Wu } 4458bc3be27SFengguang Wu } else { 4468bc3be27SFengguang Wu /* 4471da177e4SLinus Torvalds * Otherwise fully redirty the inode so that 4481da177e4SLinus Torvalds * other inodes on this superblock will get some 4491da177e4SLinus Torvalds * writeout. Otherwise heavy writing to one 4501da177e4SLinus Torvalds * file would indefinitely suspend writeout of 4511da177e4SLinus Torvalds * all the other files. 4521da177e4SLinus Torvalds */ 4531da177e4SLinus Torvalds inode->i_state |= I_DIRTY_PAGES; 4541b43ef91SAndrew Morton redirty_tail(inode); 4551da177e4SLinus Torvalds } 4561da177e4SLinus Torvalds } else if (inode->i_state & I_DIRTY) { 4571da177e4SLinus Torvalds /* 4581da177e4SLinus Torvalds * Someone redirtied the inode while were writing back 4591da177e4SLinus Torvalds * the pages. 4601da177e4SLinus Torvalds */ 4616610a0bcSAndrew Morton redirty_tail(inode); 4621da177e4SLinus Torvalds } else if (atomic_read(&inode->i_count)) { 4631da177e4SLinus Torvalds /* 4641da177e4SLinus Torvalds * The inode is clean, inuse 4651da177e4SLinus Torvalds */ 4661da177e4SLinus Torvalds list_move(&inode->i_list, &inode_in_use); 4671da177e4SLinus Torvalds } else { 4681da177e4SLinus Torvalds /* 4691da177e4SLinus Torvalds * The inode is clean, unused 4701da177e4SLinus Torvalds */ 4711da177e4SLinus Torvalds list_move(&inode->i_list, &inode_unused); 4721da177e4SLinus Torvalds } 4731da177e4SLinus Torvalds } 4741c0eeaf5SJoern Engel inode_sync_complete(inode); 4751da177e4SLinus Torvalds return ret; 4761da177e4SLinus Torvalds } 4771da177e4SLinus Torvalds 47803ba3782SJens Axboe /* 47903ba3782SJens Axboe * For WB_SYNC_NONE writeback, the caller does not have the sb pinned 48003ba3782SJens Axboe * before calling writeback. So make sure that we do pin it, so it doesn't 48103ba3782SJens Axboe * go away while we are writing inodes from it. 48203ba3782SJens Axboe * 48303ba3782SJens Axboe * Returns 0 if the super was successfully pinned (or pinning wasn't needed), 48403ba3782SJens Axboe * 1 if we failed. 48503ba3782SJens Axboe */ 48603ba3782SJens Axboe static int pin_sb_for_writeback(struct writeback_control *wbc, 48703ba3782SJens Axboe struct inode *inode) 4881da177e4SLinus Torvalds { 48903ba3782SJens Axboe struct super_block *sb = inode->i_sb; 49003ba3782SJens Axboe 49103ba3782SJens Axboe /* 49203ba3782SJens Axboe * Caller must already hold the ref for this 49303ba3782SJens Axboe */ 49403ba3782SJens Axboe if (wbc->sync_mode == WB_SYNC_ALL) { 49503ba3782SJens Axboe WARN_ON(!rwsem_is_locked(&sb->s_umount)); 49603ba3782SJens Axboe return 0; 49703ba3782SJens Axboe } 49803ba3782SJens Axboe 49903ba3782SJens Axboe spin_lock(&sb_lock); 50003ba3782SJens Axboe sb->s_count++; 50103ba3782SJens Axboe if (down_read_trylock(&sb->s_umount)) { 50203ba3782SJens Axboe if (sb->s_root) { 50303ba3782SJens Axboe spin_unlock(&sb_lock); 50403ba3782SJens Axboe return 0; 50503ba3782SJens Axboe } 50603ba3782SJens Axboe /* 50703ba3782SJens Axboe * umounted, drop rwsem again and fall through to failure 50803ba3782SJens Axboe */ 50903ba3782SJens Axboe up_read(&sb->s_umount); 51003ba3782SJens Axboe } 51103ba3782SJens Axboe 51203ba3782SJens Axboe sb->s_count--; 51303ba3782SJens Axboe spin_unlock(&sb_lock); 51403ba3782SJens Axboe return 1; 51503ba3782SJens Axboe } 51603ba3782SJens Axboe 51703ba3782SJens Axboe static void unpin_sb_for_writeback(struct writeback_control *wbc, 51803ba3782SJens Axboe struct inode *inode) 51903ba3782SJens Axboe { 52003ba3782SJens Axboe struct super_block *sb = inode->i_sb; 52103ba3782SJens Axboe 52203ba3782SJens Axboe if (wbc->sync_mode == WB_SYNC_ALL) 52303ba3782SJens Axboe return; 52403ba3782SJens Axboe 52503ba3782SJens Axboe up_read(&sb->s_umount); 52603ba3782SJens Axboe put_super(sb); 52703ba3782SJens Axboe } 52803ba3782SJens Axboe 52903ba3782SJens Axboe static void writeback_inodes_wb(struct bdi_writeback *wb, 53003ba3782SJens Axboe struct writeback_control *wbc) 53103ba3782SJens Axboe { 53203ba3782SJens Axboe struct super_block *sb = wbc->sb; 53366f3b8e2SJens Axboe const int is_blkdev_sb = sb_is_blkdev_sb(sb); 5341da177e4SLinus Torvalds const unsigned long start = jiffies; /* livelock avoidance */ 5351da177e4SLinus Torvalds 536ae8547b0SHans Reiser spin_lock(&inode_lock); 5371da177e4SLinus Torvalds 53803ba3782SJens Axboe if (!wbc->for_kupdate || list_empty(&wb->b_io)) 53903ba3782SJens Axboe queue_io(wb, wbc->older_than_this); 54066f3b8e2SJens Axboe 54103ba3782SJens Axboe while (!list_empty(&wb->b_io)) { 54203ba3782SJens Axboe struct inode *inode = list_entry(wb->b_io.prev, 5431da177e4SLinus Torvalds struct inode, i_list); 5441da177e4SLinus Torvalds long pages_skipped; 5451da177e4SLinus Torvalds 54666f3b8e2SJens Axboe /* 54766f3b8e2SJens Axboe * super block given and doesn't match, skip this inode 54866f3b8e2SJens Axboe */ 54966f3b8e2SJens Axboe if (sb && sb != inode->i_sb) { 55066f3b8e2SJens Axboe redirty_tail(inode); 55166f3b8e2SJens Axboe continue; 55266f3b8e2SJens Axboe } 55366f3b8e2SJens Axboe 55403ba3782SJens Axboe if (!bdi_cap_writeback_dirty(wb->bdi)) { 5559852a0e7SAndrew Morton redirty_tail(inode); 55666f3b8e2SJens Axboe if (is_blkdev_sb) { 5571da177e4SLinus Torvalds /* 5581da177e4SLinus Torvalds * Dirty memory-backed blockdev: the ramdisk 5591da177e4SLinus Torvalds * driver does this. Skip just this inode 5601da177e4SLinus Torvalds */ 5611da177e4SLinus Torvalds continue; 5621da177e4SLinus Torvalds } 5631da177e4SLinus Torvalds /* 5641da177e4SLinus Torvalds * Dirty memory-backed inode against a filesystem other 5651da177e4SLinus Torvalds * than the kernel-internal bdev filesystem. Skip the 5661da177e4SLinus Torvalds * entire superblock. 5671da177e4SLinus Torvalds */ 5681da177e4SLinus Torvalds break; 5691da177e4SLinus Torvalds } 5701da177e4SLinus Torvalds 57184a89245SWu Fengguang if (inode->i_state & (I_NEW | I_WILL_FREE)) { 5727ef0d737SNick Piggin requeue_io(inode); 5737ef0d737SNick Piggin continue; 5747ef0d737SNick Piggin } 5757ef0d737SNick Piggin 57603ba3782SJens Axboe if (wbc->nonblocking && bdi_write_congested(wb->bdi)) { 5771da177e4SLinus Torvalds wbc->encountered_congestion = 1; 57866f3b8e2SJens Axboe if (!is_blkdev_sb) 5791da177e4SLinus Torvalds break; /* Skip a congested fs */ 5800e0f4fc2SKen Chen requeue_io(inode); 5811da177e4SLinus Torvalds continue; /* Skip a congested blockdev */ 5821da177e4SLinus Torvalds } 5831da177e4SLinus Torvalds 584d2caa3c5SJeff Layton /* 585d2caa3c5SJeff Layton * Was this inode dirtied after sync_sb_inodes was called? 586d2caa3c5SJeff Layton * This keeps sync from extra jobs and livelock. 587d2caa3c5SJeff Layton */ 588d2caa3c5SJeff Layton if (inode_dirtied_after(inode, start)) 5891da177e4SLinus Torvalds break; 5901da177e4SLinus Torvalds 59103ba3782SJens Axboe if (pin_sb_for_writeback(wbc, inode)) { 59203ba3782SJens Axboe requeue_io(inode); 59303ba3782SJens Axboe continue; 59403ba3782SJens Axboe } 5951da177e4SLinus Torvalds 59684a89245SWu Fengguang BUG_ON(inode->i_state & (I_FREEING | I_CLEAR)); 5971da177e4SLinus Torvalds __iget(inode); 5981da177e4SLinus Torvalds pages_skipped = wbc->pages_skipped; 59901c03194SChristoph Hellwig writeback_single_inode(inode, wbc); 60003ba3782SJens Axboe unpin_sb_for_writeback(wbc, inode); 6011da177e4SLinus Torvalds if (wbc->pages_skipped != pages_skipped) { 6021da177e4SLinus Torvalds /* 6031da177e4SLinus Torvalds * writeback is not making progress due to locked 6041da177e4SLinus Torvalds * buffers. Skip this inode for now. 6051da177e4SLinus Torvalds */ 606f57b9b7bSAndrew Morton redirty_tail(inode); 6071da177e4SLinus Torvalds } 6081da177e4SLinus Torvalds spin_unlock(&inode_lock); 6091da177e4SLinus Torvalds iput(inode); 6104ffc8444SOGAWA Hirofumi cond_resched(); 6111da177e4SLinus Torvalds spin_lock(&inode_lock); 6128bc3be27SFengguang Wu if (wbc->nr_to_write <= 0) { 6138bc3be27SFengguang Wu wbc->more_io = 1; 6141da177e4SLinus Torvalds break; 6151da177e4SLinus Torvalds } 61603ba3782SJens Axboe if (!list_empty(&wb->b_more_io)) 6178bc3be27SFengguang Wu wbc->more_io = 1; 6188bc3be27SFengguang Wu } 61938f21977SNick Piggin 62066f3b8e2SJens Axboe spin_unlock(&inode_lock); 62166f3b8e2SJens Axboe /* Leave any unwritten inodes on b_io */ 62266f3b8e2SJens Axboe } 62366f3b8e2SJens Axboe 62403ba3782SJens Axboe void writeback_inodes_wbc(struct writeback_control *wbc) 62503ba3782SJens Axboe { 62603ba3782SJens Axboe struct backing_dev_info *bdi = wbc->bdi; 62703ba3782SJens Axboe 62803ba3782SJens Axboe writeback_inodes_wb(&bdi->wb, wbc); 62903ba3782SJens Axboe } 63003ba3782SJens Axboe 63103ba3782SJens Axboe /* 63203ba3782SJens Axboe * The maximum number of pages to writeout in a single bdi flush/kupdate 63303ba3782SJens Axboe * operation. We do this so we don't hold I_SYNC against an inode for 63403ba3782SJens Axboe * enormous amounts of time, which would block a userspace task which has 63503ba3782SJens Axboe * been forced to throttle against that inode. Also, the code reevaluates 63603ba3782SJens Axboe * the dirty each time it has written this many pages. 63703ba3782SJens Axboe */ 63803ba3782SJens Axboe #define MAX_WRITEBACK_PAGES 1024 63903ba3782SJens Axboe 64003ba3782SJens Axboe static inline bool over_bground_thresh(void) 64103ba3782SJens Axboe { 64203ba3782SJens Axboe unsigned long background_thresh, dirty_thresh; 64303ba3782SJens Axboe 64403ba3782SJens Axboe get_dirty_limits(&background_thresh, &dirty_thresh, NULL, NULL); 64503ba3782SJens Axboe 64603ba3782SJens Axboe return (global_page_state(NR_FILE_DIRTY) + 64703ba3782SJens Axboe global_page_state(NR_UNSTABLE_NFS) >= background_thresh); 64803ba3782SJens Axboe } 64903ba3782SJens Axboe 65003ba3782SJens Axboe /* 65103ba3782SJens Axboe * Explicit flushing or periodic writeback of "old" data. 65203ba3782SJens Axboe * 65303ba3782SJens Axboe * Define "old": the first time one of an inode's pages is dirtied, we mark the 65403ba3782SJens Axboe * dirtying-time in the inode's address_space. So this periodic writeback code 65503ba3782SJens Axboe * just walks the superblock inode list, writing back any inodes which are 65603ba3782SJens Axboe * older than a specific point in time. 65703ba3782SJens Axboe * 65803ba3782SJens Axboe * Try to run once per dirty_writeback_interval. But if a writeback event 65903ba3782SJens Axboe * takes longer than a dirty_writeback_interval interval, then leave a 66003ba3782SJens Axboe * one-second gap. 66103ba3782SJens Axboe * 66203ba3782SJens Axboe * older_than_this takes precedence over nr_to_write. So we'll only write back 66303ba3782SJens Axboe * all dirty pages if they are all attached to "old" mappings. 66403ba3782SJens Axboe */ 665c4a77a6cSJens Axboe static long wb_writeback(struct bdi_writeback *wb, 666c4a77a6cSJens Axboe struct wb_writeback_args *args) 66703ba3782SJens Axboe { 66803ba3782SJens Axboe struct writeback_control wbc = { 66903ba3782SJens Axboe .bdi = wb->bdi, 670c4a77a6cSJens Axboe .sb = args->sb, 671c4a77a6cSJens Axboe .sync_mode = args->sync_mode, 67203ba3782SJens Axboe .older_than_this = NULL, 673c4a77a6cSJens Axboe .for_kupdate = args->for_kupdate, 674c4a77a6cSJens Axboe .range_cyclic = args->range_cyclic, 67503ba3782SJens Axboe }; 67603ba3782SJens Axboe unsigned long oldest_jif; 67703ba3782SJens Axboe long wrote = 0; 67803ba3782SJens Axboe 67903ba3782SJens Axboe if (wbc.for_kupdate) { 68003ba3782SJens Axboe wbc.older_than_this = &oldest_jif; 68103ba3782SJens Axboe oldest_jif = jiffies - 68203ba3782SJens Axboe msecs_to_jiffies(dirty_expire_interval * 10); 68303ba3782SJens Axboe } 684c4a77a6cSJens Axboe if (!wbc.range_cyclic) { 685c4a77a6cSJens Axboe wbc.range_start = 0; 686c4a77a6cSJens Axboe wbc.range_end = LLONG_MAX; 687c4a77a6cSJens Axboe } 68803ba3782SJens Axboe 68903ba3782SJens Axboe for (;;) { 69003ba3782SJens Axboe /* 69103ba3782SJens Axboe * Don't flush anything for non-integrity writeback where 69203ba3782SJens Axboe * no nr_pages was given 69303ba3782SJens Axboe */ 694c4a77a6cSJens Axboe if (!args->for_kupdate && args->nr_pages <= 0 && 695c4a77a6cSJens Axboe args->sync_mode == WB_SYNC_NONE) 69603ba3782SJens Axboe break; 69703ba3782SJens Axboe 69803ba3782SJens Axboe /* 69903ba3782SJens Axboe * If no specific pages were given and this is just a 70003ba3782SJens Axboe * periodic background writeout and we are below the 70103ba3782SJens Axboe * background dirty threshold, don't do anything 70203ba3782SJens Axboe */ 703c4a77a6cSJens Axboe if (args->for_kupdate && args->nr_pages <= 0 && 704c4a77a6cSJens Axboe !over_bground_thresh()) 70503ba3782SJens Axboe break; 70603ba3782SJens Axboe 70703ba3782SJens Axboe wbc.more_io = 0; 70803ba3782SJens Axboe wbc.encountered_congestion = 0; 70903ba3782SJens Axboe wbc.nr_to_write = MAX_WRITEBACK_PAGES; 71003ba3782SJens Axboe wbc.pages_skipped = 0; 71103ba3782SJens Axboe writeback_inodes_wb(wb, &wbc); 712c4a77a6cSJens Axboe args->nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write; 71303ba3782SJens Axboe wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write; 71403ba3782SJens Axboe 71503ba3782SJens Axboe /* 71603ba3782SJens Axboe * If we ran out of stuff to write, bail unless more_io got set 71703ba3782SJens Axboe */ 71803ba3782SJens Axboe if (wbc.nr_to_write > 0 || wbc.pages_skipped > 0) { 71903ba3782SJens Axboe if (wbc.more_io && !wbc.for_kupdate) 72003ba3782SJens Axboe continue; 72103ba3782SJens Axboe break; 72203ba3782SJens Axboe } 72303ba3782SJens Axboe } 72403ba3782SJens Axboe 72503ba3782SJens Axboe return wrote; 72603ba3782SJens Axboe } 72703ba3782SJens Axboe 72803ba3782SJens Axboe /* 72903ba3782SJens Axboe * Return the next bdi_work struct that hasn't been processed by this 73003ba3782SJens Axboe * wb thread yet 73103ba3782SJens Axboe */ 73203ba3782SJens Axboe static struct bdi_work *get_next_work_item(struct backing_dev_info *bdi, 73303ba3782SJens Axboe struct bdi_writeback *wb) 73403ba3782SJens Axboe { 73503ba3782SJens Axboe struct bdi_work *work, *ret = NULL; 73603ba3782SJens Axboe 73703ba3782SJens Axboe rcu_read_lock(); 73803ba3782SJens Axboe 73903ba3782SJens Axboe list_for_each_entry_rcu(work, &bdi->work_list, list) { 74003ba3782SJens Axboe if (!test_and_clear_bit(wb->nr, &work->seen)) 74103ba3782SJens Axboe continue; 74203ba3782SJens Axboe 74303ba3782SJens Axboe ret = work; 74403ba3782SJens Axboe break; 74503ba3782SJens Axboe } 74603ba3782SJens Axboe 74703ba3782SJens Axboe rcu_read_unlock(); 74803ba3782SJens Axboe return ret; 74903ba3782SJens Axboe } 75003ba3782SJens Axboe 75103ba3782SJens Axboe static long wb_check_old_data_flush(struct bdi_writeback *wb) 75203ba3782SJens Axboe { 75303ba3782SJens Axboe unsigned long expired; 75403ba3782SJens Axboe long nr_pages; 75503ba3782SJens Axboe 75603ba3782SJens Axboe expired = wb->last_old_flush + 75703ba3782SJens Axboe msecs_to_jiffies(dirty_writeback_interval * 10); 75803ba3782SJens Axboe if (time_before(jiffies, expired)) 75903ba3782SJens Axboe return 0; 76003ba3782SJens Axboe 76103ba3782SJens Axboe wb->last_old_flush = jiffies; 76203ba3782SJens Axboe nr_pages = global_page_state(NR_FILE_DIRTY) + 76303ba3782SJens Axboe global_page_state(NR_UNSTABLE_NFS) + 76403ba3782SJens Axboe (inodes_stat.nr_inodes - inodes_stat.nr_unused); 76503ba3782SJens Axboe 766c4a77a6cSJens Axboe if (nr_pages) { 767c4a77a6cSJens Axboe struct wb_writeback_args args = { 768c4a77a6cSJens Axboe .nr_pages = nr_pages, 769c4a77a6cSJens Axboe .sync_mode = WB_SYNC_NONE, 770c4a77a6cSJens Axboe .for_kupdate = 1, 771c4a77a6cSJens Axboe .range_cyclic = 1, 772c4a77a6cSJens Axboe }; 773c4a77a6cSJens Axboe 774c4a77a6cSJens Axboe return wb_writeback(wb, &args); 775c4a77a6cSJens Axboe } 77603ba3782SJens Axboe 77703ba3782SJens Axboe return 0; 77803ba3782SJens Axboe } 77903ba3782SJens Axboe 78003ba3782SJens Axboe /* 78103ba3782SJens Axboe * Retrieve work items and do the writeback they describe 78203ba3782SJens Axboe */ 78303ba3782SJens Axboe long wb_do_writeback(struct bdi_writeback *wb, int force_wait) 78403ba3782SJens Axboe { 78503ba3782SJens Axboe struct backing_dev_info *bdi = wb->bdi; 78603ba3782SJens Axboe struct bdi_work *work; 787c4a77a6cSJens Axboe long wrote = 0; 78803ba3782SJens Axboe 78903ba3782SJens Axboe while ((work = get_next_work_item(bdi, wb)) != NULL) { 790c4a77a6cSJens Axboe struct wb_writeback_args args = work->args; 79103ba3782SJens Axboe 79203ba3782SJens Axboe /* 79303ba3782SJens Axboe * Override sync mode, in case we must wait for completion 79403ba3782SJens Axboe */ 79503ba3782SJens Axboe if (force_wait) 796c4a77a6cSJens Axboe work->args.sync_mode = args.sync_mode = WB_SYNC_ALL; 79703ba3782SJens Axboe 79803ba3782SJens Axboe /* 79903ba3782SJens Axboe * If this isn't a data integrity operation, just notify 80003ba3782SJens Axboe * that we have seen this work and we are now starting it. 80103ba3782SJens Axboe */ 802c4a77a6cSJens Axboe if (args.sync_mode == WB_SYNC_NONE) 80303ba3782SJens Axboe wb_clear_pending(wb, work); 80403ba3782SJens Axboe 805c4a77a6cSJens Axboe wrote += wb_writeback(wb, &args); 80603ba3782SJens Axboe 80703ba3782SJens Axboe /* 80803ba3782SJens Axboe * This is a data integrity writeback, so only do the 80903ba3782SJens Axboe * notification when we have completed the work. 81003ba3782SJens Axboe */ 811c4a77a6cSJens Axboe if (args.sync_mode == WB_SYNC_ALL) 81203ba3782SJens Axboe wb_clear_pending(wb, work); 81303ba3782SJens Axboe } 81403ba3782SJens Axboe 81503ba3782SJens Axboe /* 81603ba3782SJens Axboe * Check for periodic writeback, kupdated() style 81703ba3782SJens Axboe */ 81803ba3782SJens Axboe wrote += wb_check_old_data_flush(wb); 81903ba3782SJens Axboe 82003ba3782SJens Axboe return wrote; 82103ba3782SJens Axboe } 82203ba3782SJens Axboe 82303ba3782SJens Axboe /* 82403ba3782SJens Axboe * Handle writeback of dirty data for the device backed by this bdi. Also 82503ba3782SJens Axboe * wakes up periodically and does kupdated style flushing. 82603ba3782SJens Axboe */ 82703ba3782SJens Axboe int bdi_writeback_task(struct bdi_writeback *wb) 82803ba3782SJens Axboe { 82903ba3782SJens Axboe unsigned long last_active = jiffies; 83003ba3782SJens Axboe unsigned long wait_jiffies = -1UL; 83103ba3782SJens Axboe long pages_written; 83203ba3782SJens Axboe 83303ba3782SJens Axboe while (!kthread_should_stop()) { 83403ba3782SJens Axboe pages_written = wb_do_writeback(wb, 0); 83503ba3782SJens Axboe 83603ba3782SJens Axboe if (pages_written) 83703ba3782SJens Axboe last_active = jiffies; 83803ba3782SJens Axboe else if (wait_jiffies != -1UL) { 83903ba3782SJens Axboe unsigned long max_idle; 84003ba3782SJens Axboe 84103ba3782SJens Axboe /* 84203ba3782SJens Axboe * Longest period of inactivity that we tolerate. If we 84303ba3782SJens Axboe * see dirty data again later, the task will get 84403ba3782SJens Axboe * recreated automatically. 84503ba3782SJens Axboe */ 84603ba3782SJens Axboe max_idle = max(5UL * 60 * HZ, wait_jiffies); 84703ba3782SJens Axboe if (time_after(jiffies, max_idle + last_active)) 84803ba3782SJens Axboe break; 84903ba3782SJens Axboe } 85003ba3782SJens Axboe 85103ba3782SJens Axboe wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10); 85203ba3782SJens Axboe set_current_state(TASK_INTERRUPTIBLE); 85303ba3782SJens Axboe schedule_timeout(wait_jiffies); 85403ba3782SJens Axboe try_to_freeze(); 85503ba3782SJens Axboe } 85603ba3782SJens Axboe 85703ba3782SJens Axboe return 0; 85803ba3782SJens Axboe } 85903ba3782SJens Axboe 86003ba3782SJens Axboe /* 861f11fcae8SJens Axboe * Schedule writeback for all backing devices. Can only be used for 862f11fcae8SJens Axboe * WB_SYNC_NONE writeback, WB_SYNC_ALL should use bdi_start_writeback() 863f11fcae8SJens Axboe * and pass in the superblock. 86403ba3782SJens Axboe */ 86503ba3782SJens Axboe static void bdi_writeback_all(struct writeback_control *wbc) 86603ba3782SJens Axboe { 86703ba3782SJens Axboe struct backing_dev_info *bdi; 86803ba3782SJens Axboe 869f11fcae8SJens Axboe WARN_ON(wbc->sync_mode == WB_SYNC_ALL); 870f11fcae8SJens Axboe 871cfc4ba53SJens Axboe rcu_read_lock(); 87203ba3782SJens Axboe 873cfc4ba53SJens Axboe list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { 87403ba3782SJens Axboe if (!bdi_has_dirty_io(bdi)) 87503ba3782SJens Axboe continue; 87603ba3782SJens Axboe 877f11fcae8SJens Axboe bdi_alloc_queue_work(bdi, wbc); 87803ba3782SJens Axboe } 87903ba3782SJens Axboe 880cfc4ba53SJens Axboe rcu_read_unlock(); 88103ba3782SJens Axboe } 88203ba3782SJens Axboe 88303ba3782SJens Axboe /* 88403ba3782SJens Axboe * Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back 88503ba3782SJens Axboe * the whole world. 88603ba3782SJens Axboe */ 88703ba3782SJens Axboe void wakeup_flusher_threads(long nr_pages) 88803ba3782SJens Axboe { 88903ba3782SJens Axboe struct writeback_control wbc = { 89003ba3782SJens Axboe .sync_mode = WB_SYNC_NONE, 89103ba3782SJens Axboe .older_than_this = NULL, 89203ba3782SJens Axboe .range_cyclic = 1, 89303ba3782SJens Axboe }; 89403ba3782SJens Axboe 89503ba3782SJens Axboe if (nr_pages == 0) 89603ba3782SJens Axboe nr_pages = global_page_state(NR_FILE_DIRTY) + 89703ba3782SJens Axboe global_page_state(NR_UNSTABLE_NFS); 89803ba3782SJens Axboe wbc.nr_to_write = nr_pages; 89903ba3782SJens Axboe bdi_writeback_all(&wbc); 90003ba3782SJens Axboe } 90103ba3782SJens Axboe 90203ba3782SJens Axboe static noinline void block_dump___mark_inode_dirty(struct inode *inode) 90303ba3782SJens Axboe { 90403ba3782SJens Axboe if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { 90503ba3782SJens Axboe struct dentry *dentry; 90603ba3782SJens Axboe const char *name = "?"; 90703ba3782SJens Axboe 90803ba3782SJens Axboe dentry = d_find_alias(inode); 90903ba3782SJens Axboe if (dentry) { 91003ba3782SJens Axboe spin_lock(&dentry->d_lock); 91103ba3782SJens Axboe name = (const char *) dentry->d_name.name; 91203ba3782SJens Axboe } 91303ba3782SJens Axboe printk(KERN_DEBUG 91403ba3782SJens Axboe "%s(%d): dirtied inode %lu (%s) on %s\n", 91503ba3782SJens Axboe current->comm, task_pid_nr(current), inode->i_ino, 91603ba3782SJens Axboe name, inode->i_sb->s_id); 91703ba3782SJens Axboe if (dentry) { 91803ba3782SJens Axboe spin_unlock(&dentry->d_lock); 91903ba3782SJens Axboe dput(dentry); 92003ba3782SJens Axboe } 92103ba3782SJens Axboe } 92203ba3782SJens Axboe } 92303ba3782SJens Axboe 92403ba3782SJens Axboe /** 92503ba3782SJens Axboe * __mark_inode_dirty - internal function 92603ba3782SJens Axboe * @inode: inode to mark 92703ba3782SJens Axboe * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) 92803ba3782SJens Axboe * Mark an inode as dirty. Callers should use mark_inode_dirty or 92903ba3782SJens Axboe * mark_inode_dirty_sync. 93003ba3782SJens Axboe * 93103ba3782SJens Axboe * Put the inode on the super block's dirty list. 93203ba3782SJens Axboe * 93303ba3782SJens Axboe * CAREFUL! We mark it dirty unconditionally, but move it onto the 93403ba3782SJens Axboe * dirty list only if it is hashed or if it refers to a blockdev. 93503ba3782SJens Axboe * If it was not hashed, it will never be added to the dirty list 93603ba3782SJens Axboe * even if it is later hashed, as it will have been marked dirty already. 93703ba3782SJens Axboe * 93803ba3782SJens Axboe * In short, make sure you hash any inodes _before_ you start marking 93903ba3782SJens Axboe * them dirty. 94003ba3782SJens Axboe * 94103ba3782SJens Axboe * This function *must* be atomic for the I_DIRTY_PAGES case - 94203ba3782SJens Axboe * set_page_dirty() is called under spinlock in several places. 94303ba3782SJens Axboe * 94403ba3782SJens Axboe * Note that for blockdevs, inode->dirtied_when represents the dirtying time of 94503ba3782SJens Axboe * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of 94603ba3782SJens Axboe * the kernel-internal blockdev inode represents the dirtying time of the 94703ba3782SJens Axboe * blockdev's pages. This is why for I_DIRTY_PAGES we always use 94803ba3782SJens Axboe * page->mapping->host, so the page-dirtying time is recorded in the internal 94903ba3782SJens Axboe * blockdev inode. 95003ba3782SJens Axboe */ 95103ba3782SJens Axboe void __mark_inode_dirty(struct inode *inode, int flags) 95203ba3782SJens Axboe { 95303ba3782SJens Axboe struct super_block *sb = inode->i_sb; 95403ba3782SJens Axboe 95503ba3782SJens Axboe /* 95603ba3782SJens Axboe * Don't do this for I_DIRTY_PAGES - that doesn't actually 95703ba3782SJens Axboe * dirty the inode itself 95803ba3782SJens Axboe */ 95903ba3782SJens Axboe if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { 96003ba3782SJens Axboe if (sb->s_op->dirty_inode) 96103ba3782SJens Axboe sb->s_op->dirty_inode(inode); 96203ba3782SJens Axboe } 96303ba3782SJens Axboe 96403ba3782SJens Axboe /* 96503ba3782SJens Axboe * make sure that changes are seen by all cpus before we test i_state 96603ba3782SJens Axboe * -- mikulas 96703ba3782SJens Axboe */ 96803ba3782SJens Axboe smp_mb(); 96903ba3782SJens Axboe 97003ba3782SJens Axboe /* avoid the locking if we can */ 97103ba3782SJens Axboe if ((inode->i_state & flags) == flags) 97203ba3782SJens Axboe return; 97303ba3782SJens Axboe 97403ba3782SJens Axboe if (unlikely(block_dump)) 97503ba3782SJens Axboe block_dump___mark_inode_dirty(inode); 97603ba3782SJens Axboe 97703ba3782SJens Axboe spin_lock(&inode_lock); 97803ba3782SJens Axboe if ((inode->i_state & flags) != flags) { 97903ba3782SJens Axboe const int was_dirty = inode->i_state & I_DIRTY; 98003ba3782SJens Axboe 98103ba3782SJens Axboe inode->i_state |= flags; 98203ba3782SJens Axboe 98303ba3782SJens Axboe /* 98403ba3782SJens Axboe * If the inode is being synced, just update its dirty state. 98503ba3782SJens Axboe * The unlocker will place the inode on the appropriate 98603ba3782SJens Axboe * superblock list, based upon its state. 98703ba3782SJens Axboe */ 98803ba3782SJens Axboe if (inode->i_state & I_SYNC) 98903ba3782SJens Axboe goto out; 99003ba3782SJens Axboe 99103ba3782SJens Axboe /* 99203ba3782SJens Axboe * Only add valid (hashed) inodes to the superblock's 99303ba3782SJens Axboe * dirty list. Add blockdev inodes as well. 99403ba3782SJens Axboe */ 99503ba3782SJens Axboe if (!S_ISBLK(inode->i_mode)) { 99603ba3782SJens Axboe if (hlist_unhashed(&inode->i_hash)) 99703ba3782SJens Axboe goto out; 99803ba3782SJens Axboe } 99903ba3782SJens Axboe if (inode->i_state & (I_FREEING|I_CLEAR)) 100003ba3782SJens Axboe goto out; 100103ba3782SJens Axboe 100203ba3782SJens Axboe /* 100303ba3782SJens Axboe * If the inode was already on b_dirty/b_io/b_more_io, don't 100403ba3782SJens Axboe * reposition it (that would break b_dirty time-ordering). 100503ba3782SJens Axboe */ 100603ba3782SJens Axboe if (!was_dirty) { 100703ba3782SJens Axboe struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; 1008500b067cSJens Axboe struct backing_dev_info *bdi = wb->bdi; 1009500b067cSJens Axboe 1010500b067cSJens Axboe if (bdi_cap_writeback_dirty(bdi) && 1011500b067cSJens Axboe !test_bit(BDI_registered, &bdi->state)) { 1012500b067cSJens Axboe WARN_ON(1); 1013500b067cSJens Axboe printk(KERN_ERR "bdi-%s not registered\n", 1014500b067cSJens Axboe bdi->name); 1015500b067cSJens Axboe } 101603ba3782SJens Axboe 101703ba3782SJens Axboe inode->dirtied_when = jiffies; 101803ba3782SJens Axboe list_move(&inode->i_list, &wb->b_dirty); 101903ba3782SJens Axboe } 102003ba3782SJens Axboe } 102103ba3782SJens Axboe out: 102203ba3782SJens Axboe spin_unlock(&inode_lock); 102303ba3782SJens Axboe } 102403ba3782SJens Axboe EXPORT_SYMBOL(__mark_inode_dirty); 102503ba3782SJens Axboe 102666f3b8e2SJens Axboe /* 102766f3b8e2SJens Axboe * Write out a superblock's list of dirty inodes. A wait will be performed 102866f3b8e2SJens Axboe * upon no inodes, all inodes or the final one, depending upon sync_mode. 102966f3b8e2SJens Axboe * 103066f3b8e2SJens Axboe * If older_than_this is non-NULL, then only write out inodes which 103166f3b8e2SJens Axboe * had their first dirtying at a time earlier than *older_than_this. 103266f3b8e2SJens Axboe * 103366f3b8e2SJens Axboe * If we're a pdlfush thread, then implement pdflush collision avoidance 103466f3b8e2SJens Axboe * against the entire list. 103566f3b8e2SJens Axboe * 103666f3b8e2SJens Axboe * If `bdi' is non-zero then we're being asked to writeback a specific queue. 103766f3b8e2SJens Axboe * This function assumes that the blockdev superblock's inodes are backed by 103866f3b8e2SJens Axboe * a variety of queues, so all inodes are searched. For other superblocks, 103966f3b8e2SJens Axboe * assume that all inodes are backed by the same queue. 104066f3b8e2SJens Axboe * 104166f3b8e2SJens Axboe * The inodes to be written are parked on bdi->b_io. They are moved back onto 104266f3b8e2SJens Axboe * bdi->b_dirty as they are selected for writing. This way, none can be missed 104366f3b8e2SJens Axboe * on the writer throttling path, and we get decent balancing between many 104466f3b8e2SJens Axboe * throttled threads: we don't want them all piling up on inode_sync_wait. 104566f3b8e2SJens Axboe */ 104603ba3782SJens Axboe static void wait_sb_inodes(struct writeback_control *wbc) 104766f3b8e2SJens Axboe { 104838f21977SNick Piggin struct inode *inode, *old_inode = NULL; 104938f21977SNick Piggin 105003ba3782SJens Axboe /* 105103ba3782SJens Axboe * We need to be protected against the filesystem going from 105203ba3782SJens Axboe * r/o to r/w or vice versa. 105303ba3782SJens Axboe */ 105403ba3782SJens Axboe WARN_ON(!rwsem_is_locked(&wbc->sb->s_umount)); 105503ba3782SJens Axboe 105666f3b8e2SJens Axboe spin_lock(&inode_lock); 105766f3b8e2SJens Axboe 105838f21977SNick Piggin /* 105938f21977SNick Piggin * Data integrity sync. Must wait for all pages under writeback, 106038f21977SNick Piggin * because there may have been pages dirtied before our sync 106138f21977SNick Piggin * call, but which had writeout started before we write it out. 106238f21977SNick Piggin * In which case, the inode may not be on the dirty list, but 106338f21977SNick Piggin * we still have to wait for that writeout. 106438f21977SNick Piggin */ 106503ba3782SJens Axboe list_for_each_entry(inode, &wbc->sb->s_inodes, i_sb_list) { 106638f21977SNick Piggin struct address_space *mapping; 106738f21977SNick Piggin 106803ba3782SJens Axboe if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW)) 106938f21977SNick Piggin continue; 107038f21977SNick Piggin mapping = inode->i_mapping; 107138f21977SNick Piggin if (mapping->nrpages == 0) 107238f21977SNick Piggin continue; 107338f21977SNick Piggin __iget(inode); 1074ae8547b0SHans Reiser spin_unlock(&inode_lock); 107538f21977SNick Piggin /* 107638f21977SNick Piggin * We hold a reference to 'inode' so it couldn't have 107738f21977SNick Piggin * been removed from s_inodes list while we dropped the 107838f21977SNick Piggin * inode_lock. We cannot iput the inode now as we can 107938f21977SNick Piggin * be holding the last reference and we cannot iput it 108038f21977SNick Piggin * under inode_lock. So we keep the reference and iput 108138f21977SNick Piggin * it later. 108238f21977SNick Piggin */ 108338f21977SNick Piggin iput(old_inode); 108438f21977SNick Piggin old_inode = inode; 108538f21977SNick Piggin 108638f21977SNick Piggin filemap_fdatawait(mapping); 108738f21977SNick Piggin 108838f21977SNick Piggin cond_resched(); 108938f21977SNick Piggin 109038f21977SNick Piggin spin_lock(&inode_lock); 109138f21977SNick Piggin } 109238f21977SNick Piggin spin_unlock(&inode_lock); 109338f21977SNick Piggin iput(old_inode); 109466f3b8e2SJens Axboe } 10951da177e4SLinus Torvalds 1096d8a8559cSJens Axboe /** 1097d8a8559cSJens Axboe * writeback_inodes_sb - writeback dirty inodes from given super_block 1098d8a8559cSJens Axboe * @sb: the superblock 10991da177e4SLinus Torvalds * 1100d8a8559cSJens Axboe * Start writeback on some inodes on this super_block. No guarantees are made 1101d8a8559cSJens Axboe * on how many (if any) will be written, and this function does not wait 1102d8a8559cSJens Axboe * for IO completion of submitted IO. The number of pages submitted is 1103d8a8559cSJens Axboe * returned. 11041da177e4SLinus Torvalds */ 1105d8a8559cSJens Axboe long writeback_inodes_sb(struct super_block *sb) 11061da177e4SLinus Torvalds { 11071da177e4SLinus Torvalds struct writeback_control wbc = { 110803ba3782SJens Axboe .sb = sb, 1109d8a8559cSJens Axboe .sync_mode = WB_SYNC_NONE, 1110111ebb6eSOGAWA Hirofumi .range_start = 0, 1111111ebb6eSOGAWA Hirofumi .range_end = LLONG_MAX, 11121da177e4SLinus Torvalds }; 1113b1e7a8fdSChristoph Lameter unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY); 1114fd39fc85SChristoph Lameter unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS); 1115d8a8559cSJens Axboe long nr_to_write; 11161da177e4SLinus Torvalds 1117d8a8559cSJens Axboe nr_to_write = nr_dirty + nr_unstable + 111838f21977SNick Piggin (inodes_stat.nr_inodes - inodes_stat.nr_unused); 111938f21977SNick Piggin 1120d8a8559cSJens Axboe wbc.nr_to_write = nr_to_write; 112103ba3782SJens Axboe bdi_writeback_all(&wbc); 1122d8a8559cSJens Axboe return nr_to_write - wbc.nr_to_write; 11231da177e4SLinus Torvalds } 1124d8a8559cSJens Axboe EXPORT_SYMBOL(writeback_inodes_sb); 1125d8a8559cSJens Axboe 1126d8a8559cSJens Axboe /** 1127d8a8559cSJens Axboe * sync_inodes_sb - sync sb inode pages 1128d8a8559cSJens Axboe * @sb: the superblock 1129d8a8559cSJens Axboe * 1130d8a8559cSJens Axboe * This function writes and waits on any dirty inode belonging to this 1131d8a8559cSJens Axboe * super_block. The number of pages synced is returned. 1132d8a8559cSJens Axboe */ 1133d8a8559cSJens Axboe long sync_inodes_sb(struct super_block *sb) 1134d8a8559cSJens Axboe { 1135d8a8559cSJens Axboe struct writeback_control wbc = { 113603ba3782SJens Axboe .sb = sb, 1137f11fcae8SJens Axboe .bdi = sb->s_bdi, 1138d8a8559cSJens Axboe .sync_mode = WB_SYNC_ALL, 1139d8a8559cSJens Axboe .range_start = 0, 1140d8a8559cSJens Axboe .range_end = LLONG_MAX, 1141d8a8559cSJens Axboe }; 1142d8a8559cSJens Axboe long nr_to_write = LONG_MAX; /* doesn't actually matter */ 1143d8a8559cSJens Axboe 1144d8a8559cSJens Axboe wbc.nr_to_write = nr_to_write; 1145f11fcae8SJens Axboe bdi_start_writeback(&wbc); 114603ba3782SJens Axboe wait_sb_inodes(&wbc); 1147d8a8559cSJens Axboe return nr_to_write - wbc.nr_to_write; 1148d8a8559cSJens Axboe } 1149d8a8559cSJens Axboe EXPORT_SYMBOL(sync_inodes_sb); 11501da177e4SLinus Torvalds 11511da177e4SLinus Torvalds /** 11521da177e4SLinus Torvalds * write_inode_now - write an inode to disk 11531da177e4SLinus Torvalds * @inode: inode to write to disk 11541da177e4SLinus Torvalds * @sync: whether the write should be synchronous or not 11551da177e4SLinus Torvalds * 11567f04c26dSAndrea Arcangeli * This function commits an inode to disk immediately if it is dirty. This is 11577f04c26dSAndrea Arcangeli * primarily needed by knfsd. 11587f04c26dSAndrea Arcangeli * 11597f04c26dSAndrea Arcangeli * The caller must either have a ref on the inode or must have set I_WILL_FREE. 11601da177e4SLinus Torvalds */ 11611da177e4SLinus Torvalds int write_inode_now(struct inode *inode, int sync) 11621da177e4SLinus Torvalds { 11631da177e4SLinus Torvalds int ret; 11641da177e4SLinus Torvalds struct writeback_control wbc = { 11651da177e4SLinus Torvalds .nr_to_write = LONG_MAX, 116618914b18SMike Galbraith .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE, 1167111ebb6eSOGAWA Hirofumi .range_start = 0, 1168111ebb6eSOGAWA Hirofumi .range_end = LLONG_MAX, 11691da177e4SLinus Torvalds }; 11701da177e4SLinus Torvalds 11711da177e4SLinus Torvalds if (!mapping_cap_writeback_dirty(inode->i_mapping)) 117249364ce2SAndrew Morton wbc.nr_to_write = 0; 11731da177e4SLinus Torvalds 11741da177e4SLinus Torvalds might_sleep(); 11751da177e4SLinus Torvalds spin_lock(&inode_lock); 117601c03194SChristoph Hellwig ret = writeback_single_inode(inode, &wbc); 11771da177e4SLinus Torvalds spin_unlock(&inode_lock); 11781da177e4SLinus Torvalds if (sync) 11791c0eeaf5SJoern Engel inode_sync_wait(inode); 11801da177e4SLinus Torvalds return ret; 11811da177e4SLinus Torvalds } 11821da177e4SLinus Torvalds EXPORT_SYMBOL(write_inode_now); 11831da177e4SLinus Torvalds 11841da177e4SLinus Torvalds /** 11851da177e4SLinus Torvalds * sync_inode - write an inode and its pages to disk. 11861da177e4SLinus Torvalds * @inode: the inode to sync 11871da177e4SLinus Torvalds * @wbc: controls the writeback mode 11881da177e4SLinus Torvalds * 11891da177e4SLinus Torvalds * sync_inode() will write an inode and its pages to disk. It will also 11901da177e4SLinus Torvalds * correctly update the inode on its superblock's dirty inode lists and will 11911da177e4SLinus Torvalds * update inode->i_state. 11921da177e4SLinus Torvalds * 11931da177e4SLinus Torvalds * The caller must have a ref on the inode. 11941da177e4SLinus Torvalds */ 11951da177e4SLinus Torvalds int sync_inode(struct inode *inode, struct writeback_control *wbc) 11961da177e4SLinus Torvalds { 11971da177e4SLinus Torvalds int ret; 11981da177e4SLinus Torvalds 11991da177e4SLinus Torvalds spin_lock(&inode_lock); 120001c03194SChristoph Hellwig ret = writeback_single_inode(inode, wbc); 12011da177e4SLinus Torvalds spin_unlock(&inode_lock); 12021da177e4SLinus Torvalds return ret; 12031da177e4SLinus Torvalds } 12041da177e4SLinus Torvalds EXPORT_SYMBOL(sync_inode); 1205