| /* |
| * fs/fs-writeback.c |
| * |
| * Copyright (C) 2002, Linus Torvalds. |
| * |
| * Contains all the functions related to writing back and waiting |
| * upon dirty inodes against superblocks, and writing back dirty |
| * pages against inodes. ie: data writeback. Writeout of the |
| * inode itself is not handled here. |
| * |
| * 10Apr2002 Andrew Morton |
| * Split out of fs/inode.c |
| * Additions for address_space-based writeback |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/export.h> |
| #include <linux/spinlock.h> |
| #include <linux/slab.h> |
| #include <linux/sched.h> |
| #include <linux/fs.h> |
| #include <linux/mm.h> |
| #include <linux/pagemap.h> |
| #include <linux/kthread.h> |
| #include <linux/writeback.h> |
| #include <linux/blkdev.h> |
| #include <linux/backing-dev.h> |
| #include <linux/tracepoint.h> |
| #include <linux/device.h> |
| #include "internal.h" |
| |
| /* |
| * 4MB minimal write chunk size |
| */ |
| #define MIN_WRITEBACK_PAGES (4096UL >> (PAGE_CACHE_SHIFT - 10)) |
| |
| /* |
| * Passed into wb_writeback(), essentially a subset of writeback_control |
| */ |
| struct wb_writeback_work { |
| long nr_pages; |
| struct super_block *sb; |
| /* |
| * Write only inodes dirtied before this time. Don't forget to set |
| * older_than_this_is_set when you set this. |
| */ |
| unsigned long older_than_this; |
| enum writeback_sync_modes sync_mode; |
| unsigned int tagged_writepages:1; |
| unsigned int for_kupdate:1; |
| unsigned int range_cyclic:1; |
| unsigned int for_background:1; |
| unsigned int for_sync:1; /* sync(2) WB_SYNC_ALL writeback */ |
| unsigned int older_than_this_is_set:1; |
| enum wb_reason reason; /* why was writeback initiated? */ |
| |
| struct list_head list; /* pending work list */ |
| struct completion *done; /* set if the caller waits */ |
| }; |
| |
| /** |
| * writeback_in_progress - determine whether there is writeback in progress |
| * @bdi: the device's backing_dev_info structure. |
| * |
| * Determine whether there is writeback waiting to be handled against a |
| * backing device. |
| */ |
| int writeback_in_progress(struct backing_dev_info *bdi) |
| { |
| return test_bit(BDI_writeback_running, &bdi->state); |
| } |
| EXPORT_SYMBOL(writeback_in_progress); |
| |
| static inline struct backing_dev_info *inode_to_bdi(struct inode *inode) |
| { |
| struct super_block *sb = inode->i_sb; |
| |
| if (sb_is_blkdev_sb(sb)) |
| return inode->i_mapping->backing_dev_info; |
| |
| return sb->s_bdi; |
| } |
| |
| static inline struct inode *wb_inode(struct list_head *head) |
| { |
| return list_entry(head, struct inode, i_wb_list); |
| } |
| |
| /* |
| * Include the creation of the trace points after defining the |
| * wb_writeback_work structure and inline functions so that the definition |
| * remains local to this file. |
| */ |
| #define CREATE_TRACE_POINTS |
| #include <trace/events/writeback.h> |
| |
| EXPORT_TRACEPOINT_SYMBOL_GPL(wbc_writepage); |
| |
| static void bdi_queue_work(struct backing_dev_info *bdi, |
| struct wb_writeback_work *work) |
| { |
| trace_writeback_queue(bdi, work); |
| |
| spin_lock_bh(&bdi->wb_lock); |
| list_add_tail(&work->list, &bdi->work_list); |
| spin_unlock_bh(&bdi->wb_lock); |
| |
| mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); |
| } |
| |
| static void |
| __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, |
| bool range_cyclic, enum wb_reason reason) |
| { |
| struct wb_writeback_work *work; |
| |
| /* |
| * This is WB_SYNC_NONE writeback, so if allocation fails just |
| * wakeup the thread for old dirty data writeback |
| */ |
| work = kzalloc(sizeof(*work), GFP_ATOMIC); |
| if (!work) { |
| trace_writeback_nowork(bdi); |
| mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); |
| return; |
| } |
| |
| work->sync_mode = WB_SYNC_NONE; |
| work->nr_pages = nr_pages; |
| work->range_cyclic = range_cyclic; |
| work->reason = reason; |
| |
| bdi_queue_work(bdi, work); |
| } |
| |
| /** |
| * bdi_start_writeback - start writeback |
| * @bdi: the backing device to write from |
| * @nr_pages: the number of pages to write |
| * @reason: reason why some writeback work was initiated |
| * |
| * Description: |
| * This does WB_SYNC_NONE opportunistic writeback. The IO is only |
| * started when this function returns, we make no guarantees on |
| * completion. Caller need not hold sb s_umount semaphore. |
| * |
| */ |
| void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, |
| enum wb_reason reason) |
| { |
| __bdi_start_writeback(bdi, nr_pages, true, reason); |
| } |
| |
| /** |
| * bdi_start_background_writeback - start background writeback |
| * @bdi: the backing device to write from |
| * |
| * Description: |
| * This makes sure WB_SYNC_NONE background writeback happens. When |
| * this function returns, it is only guaranteed that for given BDI |
| * some IO is happening if we are over background dirty threshold. |
| * Caller need not hold sb s_umount semaphore. |
| */ |
| void bdi_start_background_writeback(struct backing_dev_info *bdi) |
| { |
| /* |
| * We just wake up the flusher thread. It will perform background |
| * writeback as soon as there is no other work to do. |
| */ |
| trace_writeback_wake_background(bdi); |
| mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); |
| } |
| |
| /* |
| * Remove the inode from the writeback list it is on. |
| */ |
| void inode_wb_list_del(struct inode *inode) |
| { |
| struct backing_dev_info *bdi = inode_to_bdi(inode); |
| |
| spin_lock(&bdi->wb.list_lock); |
| list_del_init(&inode->i_wb_list); |
| spin_unlock(&bdi->wb.list_lock); |
| } |
| |
| /* |
| * Redirty an inode: set its when-it-was dirtied timestamp and move it to the |
| * furthest end of its superblock's dirty-inode list. |
| * |
| * Before stamping the inode's ->dirtied_when, we check to see whether it is |
| * already the most-recently-dirtied inode on the b_dirty list. If that is |
| * the case then the inode must have been redirtied while it was being written |
| * out and we don't reset its dirtied_when. |
| */ |
| static void redirty_tail(struct inode *inode, struct bdi_writeback *wb) |
| { |
| assert_spin_locked(&wb->list_lock); |
| if (!list_empty(&wb->b_dirty)) { |
| struct inode *tail; |
| |
| tail = wb_inode(wb->b_dirty.next); |
| if (time_before(inode->dirtied_when, tail->dirtied_when)) |
| inode->dirtied_when = jiffies; |
| } |
| list_move(&inode->i_wb_list, &wb->b_dirty); |
| } |
| |
| /* |
| * requeue inode for re-scanning after bdi->b_io list is exhausted. |
| */ |
| static void requeue_io(struct inode *inode, struct bdi_writeback *wb) |
| { |
| assert_spin_locked(&wb->list_lock); |
| list_move(&inode->i_wb_list, &wb->b_more_io); |
| } |
| |
| static void inode_sync_complete(struct inode *inode) |
| { |
| inode->i_state &= ~I_SYNC; |
| /* If inode is clean an unused, put it into LRU now... */ |
| inode_add_lru(inode); |
| /* Waiters must see I_SYNC cleared before being woken up */ |
| smp_mb(); |
| wake_up_bit(&inode->i_state, __I_SYNC); |
| } |
| |
| static bool inode_dirtied_after(struct inode *inode, unsigned long t) |
| { |
| bool ret = time_after(inode->dirtied_when, t); |
| #ifndef CONFIG_64BIT |
| /* |
| * For inodes being constantly redirtied, dirtied_when can get stuck. |
| * It _appears_ to be in the future, but is actually in distant past. |
| * This test is necessary to prevent such wrapped-around relative times |
| * from permanently stopping the whole bdi writeback. |
| */ |
| ret = ret && time_before_eq(inode->dirtied_when, jiffies); |
| #endif |
| return ret; |
| } |
| |
| /* |
| * Move expired (dirtied before work->older_than_this) dirty inodes from |
| * @delaying_queue to @dispatch_queue. |
| */ |
| static int move_expired_inodes(struct list_head *delaying_queue, |
| struct list_head *dispatch_queue, |
| struct wb_writeback_work *work) |
| { |
| LIST_HEAD(tmp); |
| struct list_head *pos, *node; |
| struct super_block *sb = NULL; |
| struct inode *inode; |
| int do_sb_sort = 0; |
| int moved = 0; |
| |
| WARN_ON_ONCE(!work->older_than_this_is_set); |
| while (!list_empty(delaying_queue)) { |
| inode = wb_inode(delaying_queue->prev); |
| if (inode_dirtied_after(inode, work->older_than_this)) |
| break; |
| list_move(&inode->i_wb_list, &tmp); |
| moved++; |
| if (sb_is_blkdev_sb(inode->i_sb)) |
| continue; |
| if (sb && sb != inode->i_sb) |
| do_sb_sort = 1; |
| sb = inode->i_sb; |
| } |
| |
| /* just one sb in list, splice to dispatch_queue and we're done */ |
| if (!do_sb_sort) { |
| list_splice(&tmp, dispatch_queue); |
| goto out; |
| } |
| |
| /* Move inodes from one superblock together */ |
| while (!list_empty(&tmp)) { |
| sb = wb_inode(tmp.prev)->i_sb; |
| list_for_each_prev_safe(pos, node, &tmp) { |
| inode = wb_inode(pos); |
| if (inode->i_sb == sb) |
| list_move(&inode->i_wb_list, dispatch_queue); |
| } |
| } |
| out: |
| return moved; |
| } |
| |
| /* |
| * Queue all expired dirty inodes for io, eldest first. |
| * Before |
| * newly dirtied b_dirty b_io b_more_io |
| * =============> gf edc BA |
| * After |
| * newly dirtied b_dirty b_io b_more_io |
| * =============> g fBAedc |
| * | |
| * +--> dequeue for IO |
| */ |
| static void queue_io(struct bdi_writeback *wb, struct wb_writeback_work *work) |
| { |
| int moved; |
| assert_spin_locked(&wb->list_lock); |
| list_splice_init(&wb->b_more_io, &wb->b_io); |
| moved = move_expired_inodes(&wb->b_dirty, &wb->b_io, work); |
| trace_writeback_queue_io(wb, work, moved); |
| } |
| |
| static int write_inode(struct inode *inode, struct writeback_control *wbc) |
| { |
| int ret; |
| |
| if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) { |
| trace_writeback_write_inode_start(inode, wbc); |
| ret = inode->i_sb->s_op->write_inode(inode, wbc); |
| trace_writeback_write_inode(inode, wbc); |
| return ret; |
| } |
| return 0; |
| } |
| |
| /* |
| * Wait for writeback on an inode to complete. Called with i_lock held. |
| * Caller must make sure inode cannot go away when we drop i_lock. |
| */ |
| static void __inode_wait_for_writeback(struct inode *inode) |
| __releases(inode->i_lock) |
| __acquires(inode->i_lock) |
| { |
| DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); |
| wait_queue_head_t *wqh; |
| |
| wqh = bit_waitqueue(&inode->i_state, __I_SYNC); |
| while (inode->i_state & I_SYNC) { |
| spin_unlock(&inode->i_lock); |
| __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE); |
| spin_lock(&inode->i_lock); |
| } |
| } |
| |
| /* |
| * Wait for writeback on an inode to complete. Caller must have inode pinned. |
| */ |
| void inode_wait_for_writeback(struct inode *inode) |
| { |
| spin_lock(&inode->i_lock); |
| __inode_wait_for_writeback(inode); |
| spin_unlock(&inode->i_lock); |
| } |
| |
| /* |
| * Sleep until I_SYNC is cleared. This function must be called with i_lock |
| * held and drops it. It is aimed for callers not holding any inode reference |
| * so once i_lock is dropped, inode can go away. |
| */ |
| static void inode_sleep_on_writeback(struct inode *inode) |
| __releases(inode->i_lock) |
| { |
| DEFINE_WAIT(wait); |
| wait_queue_head_t *wqh = bit_waitqueue(&inode->i_state, __I_SYNC); |
| int sleep; |
| |
| prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); |
| sleep = inode->i_state & I_SYNC; |
| spin_unlock(&inode->i_lock); |
| if (sleep) |
| schedule(); |
| finish_wait(wqh, &wait); |
| } |
| |
| /* |
| * Find proper writeback list for the inode depending on its current state and |
| * possibly also change of its state while we were doing writeback. Here we |
| * handle things such as livelock prevention or fairness of writeback among |
| * inodes. This function can be called only by flusher thread - noone else |
| * processes all inodes in writeback lists and requeueing inodes behind flusher |
| * thread's back can have unexpected consequences. |
| */ |
| static void requeue_inode(struct inode *inode, struct bdi_writeback *wb, |
| struct writeback_control *wbc) |
| { |
| if (inode->i_state & I_FREEING) |
| return; |
| |
| /* |
| * Sync livelock prevention. Each inode is tagged and synced in one |
| * shot. If still dirty, it will be redirty_tail()'ed below. Update |
| * the dirty time to prevent enqueue and sync it again. |
| */ |
| if ((inode->i_state & I_DIRTY) && |
| (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)) |
| inode->dirtied_when = jiffies; |
| |
| if (wbc->pages_skipped) { |
| /* |
| * writeback is not making progress due to locked |
| * buffers. Skip this inode for now. |
| */ |
| redirty_tail(inode, wb); |
| return; |
| } |
| |
| if (mapping_tagged(inode->i_mapping, PAGECACHE_TAG_DIRTY)) { |
| /* |
| * We didn't write back all the pages. nfs_writepages() |
| * sometimes bales out without doing anything. |
| */ |
| if (wbc->nr_to_write <= 0) { |
| /* Slice used up. Queue for next turn. */ |
| requeue_io(inode, wb); |
| } else { |
| /* |
| * Writeback blocked by something other than |
| * congestion. Delay the inode for some time to |
| * avoid spinning on the CPU (100% iowait) |
| * retrying writeback of the dirty page/inode |
| * that cannot be performed immediately. |
| */ |
| redirty_tail(inode, wb); |
| } |
| } else if (inode->i_state & I_DIRTY) { |
| /* |
| * Filesystems can dirty the inode during writeback operations, |
| * such as delayed allocation during submission or metadata |
| * updates after data IO completion. |
| */ |
| redirty_tail(inode, wb); |
| } else { |
| /* The inode is clean. Remove from writeback lists. */ |
| list_del_init(&inode->i_wb_list); |
| } |
| } |
| |
| /* |
| * Write out an inode and its dirty pages. Do not update the writeback list |
| * linkage. That is left to the caller. The caller is also responsible for |
| * setting I_SYNC flag and calling inode_sync_complete() to clear it. |
| */ |
| static int |
| __writeback_single_inode(struct inode *inode, struct writeback_control *wbc) |
| { |
| struct address_space *mapping = inode->i_mapping; |
| long nr_to_write = wbc->nr_to_write; |
| unsigned dirty; |
| int ret; |
| |
| WARN_ON(!(inode->i_state & I_SYNC)); |
| |
| trace_writeback_single_inode_start(inode, wbc, nr_to_write); |
| |
| ret = do_writepages(mapping, wbc); |
| |
| /* |
| * Make sure to wait on the data before writing out the metadata. |
| * This is important for filesystems that modify metadata on data |
| * I/O completion. We don't do it for sync(2) writeback because it has a |
| * separate, external IO completion path and ->sync_fs for guaranteeing |
| * inode metadata is written back correctly. |
| */ |
| if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync) { |
| int err = filemap_fdatawait(mapping); |
| if (ret == 0) |
| ret = err; |
| } |
| |
| /* |
| * Some filesystems may redirty the inode during the writeback |
| * due to delalloc, clear dirty metadata flags right before |
| * write_inode() |
| */ |
| spin_lock(&inode->i_lock); |
| /* Clear I_DIRTY_PAGES if we've written out all dirty pages */ |
| if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) |
| inode->i_state &= ~I_DIRTY_PAGES; |
| dirty = inode->i_state & I_DIRTY; |
| inode->i_state &= ~(I_DIRTY_SYNC | I_DIRTY_DATASYNC); |
| spin_unlock(&inode->i_lock); |
| /* Don't write the inode if only I_DIRTY_PAGES was set */ |
| if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { |
| int err = write_inode(inode, wbc); |
| if (ret == 0) |
| ret = err; |
| } |
| trace_writeback_single_inode(inode, wbc, nr_to_write); |
| return ret; |
| } |
| |
| /* |
| * Write out an inode's dirty pages. Either the caller has an active reference |
| * on the inode or the inode has I_WILL_FREE set. |
| * |
| * This function is designed to be called for writing back one inode which |
| * we go e.g. from filesystem. Flusher thread uses __writeback_single_inode() |
| * and does more profound writeback list handling in writeback_sb_inodes(). |
| */ |
| static int |
| writeback_single_inode(struct inode *inode, struct bdi_writeback *wb, |
| struct writeback_control *wbc) |
| { |
| int ret = 0; |
| |
| spin_lock(&inode->i_lock); |
| if (!atomic_read(&inode->i_count)) |
| WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); |
| else |
| WARN_ON(inode->i_state & I_WILL_FREE); |
| |
| if (inode->i_state & I_SYNC) { |
| if (wbc->sync_mode != WB_SYNC_ALL) |
| goto out; |
| /* |
| * It's a data-integrity sync. We must wait. Since callers hold |
| * inode reference or inode has I_WILL_FREE set, it cannot go |
| * away under us. |
| */ |
| __inode_wait_for_writeback(inode); |
| } |
| WARN_ON(inode->i_state & I_SYNC); |
| /* |
| * Skip inode if it is clean and we have no outstanding writeback in |
| * WB_SYNC_ALL mode. We don't want to mess with writeback lists in this |
| * function since flusher thread may be doing for example sync in |
| * parallel and if we move the inode, it could get skipped. So here we |
| * make sure inode is on some writeback list and leave it there unless |
| * we have completely cleaned the inode. |
| */ |
| if (!(inode->i_state & I_DIRTY) && |
| (wbc->sync_mode != WB_SYNC_ALL || |
| !mapping_tagged(inode->i_mapping, PAGECACHE_TAG_WRITEBACK))) |
| goto out; |
| inode->i_state |= I_SYNC; |
| spin_unlock(&inode->i_lock); |
| |
| ret = __writeback_single_inode(inode, wbc); |
| |
| spin_lock(&wb->list_lock); |
| spin_lock(&inode->i_lock); |
| /* |
| * If inode is clean, remove it from writeback lists. Otherwise don't |
| * touch it. See comment above for explanation. |
| */ |
| if (!(inode->i_state & I_DIRTY)) |
| list_del_init(&inode->i_wb_list); |
| spin_unlock(&wb->list_lock); |
| inode_sync_complete(inode); |
| out: |
| spin_unlock(&inode->i_lock); |
| return ret; |
| } |
| |
| static long writeback_chunk_size(struct backing_dev_info *bdi, |
| struct wb_writeback_work *work) |
| { |
| long pages; |
| |
| /* |
| * WB_SYNC_ALL mode does livelock avoidance by syncing dirty |
| * inodes/pages in one big loop. Setting wbc.nr_to_write=LONG_MAX |
| * here avoids calling into writeback_inodes_wb() more than once. |
| * |
| * The intended call sequence for WB_SYNC_ALL writeback is: |
| * |
| * wb_writeback() |
| * writeback_sb_inodes() <== called only once |
| * write_cache_pages() <== called once for each inode |
| * (quickly) tag currently dirty pages |
| * (maybe slowly) sync all tagged pages |
| */ |
| if (work->sync_mode == WB_SYNC_ALL || work->tagged_writepages) |
| pages = LONG_MAX; |
| else { |
| pages = min(bdi->avg_write_bandwidth / 2, |
| global_dirty_limit / DIRTY_SCOPE); |
| pages = min(pages, work->nr_pages); |
| pages = round_down(pages + MIN_WRITEBACK_PAGES, |
| MIN_WRITEBACK_PAGES); |
| } |
| |
| return pages; |
| } |
| |
| /* |
| * Write a portion of b_io inodes which belong to @sb. |
| * |
| * Return the number of pages and/or inodes written. |
| */ |
| static long writeback_sb_inodes(struct super_block *sb, |
| struct bdi_writeback *wb, |
| struct wb_writeback_work *work) |
| { |
| struct writeback_control wbc = { |
| .sync_mode = work->sync_mode, |
| .tagged_writepages = work->tagged_writepages, |
| .for_kupdate = work->for_kupdate, |
| .for_background = work->for_background, |
| .for_sync = work->for_sync, |
| .range_cyclic = work->range_cyclic, |
| .range_start = 0, |
| .range_end = LLONG_MAX, |
| }; |
| unsigned long start_time = jiffies; |
| long write_chunk; |
| long wrote = 0; /* count both pages and inodes */ |
| |
| while (!list_empty(&wb->b_io)) { |
| struct inode *inode = wb_inode(wb->b_io.prev); |
| |
| if (inode->i_sb != sb) { |
| if (work->sb) { |
| /* |
| * We only want to write back data for this |
| * superblock, move all inodes not belonging |
| * to it back onto the dirty list. |
| */ |
| redirty_tail(inode, wb); |
| continue; |
| } |
| |
| /* |
| * The inode belongs to a different superblock. |
| * Bounce back to the caller to unpin this and |
| * pin the next superblock. |
| */ |
| break; |
| } |
| |
| /* |
| * Don't bother with new inodes or inodes being freed, first |
| * kind does not need periodic writeout yet, and for the latter |
| * kind writeout is handled by the freer. |
| */ |
| spin_lock(&inode->i_lock); |
| if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
| spin_unlock(&inode->i_lock); |
| redirty_tail(inode, wb); |
| continue; |
| } |
| if ((inode->i_state & I_SYNC) && wbc.sync_mode != WB_SYNC_ALL) { |
| /* |
| * If this inode is locked for writeback and we are not |
| * doing writeback-for-data-integrity, move it to |
| * b_more_io so that writeback can proceed with the |
| * other inodes on s_io. |
| * |
| * We'll have another go at writing back this inode |
| * when we completed a full scan of b_io. |
| */ |
| spin_unlock(&inode->i_lock); |
| requeue_io(inode, wb); |
| trace_writeback_sb_inodes_requeue(inode); |
| continue; |
| } |
| spin_unlock(&wb->list_lock); |
| |
| /* |
| * We already requeued the inode if it had I_SYNC set and we |
| * are doing WB_SYNC_NONE writeback. So this catches only the |
| * WB_SYNC_ALL case. |
| */ |
| if (inode->i_state & I_SYNC) { |
| /* Wait for I_SYNC. This function drops i_lock... */ |
| inode_sleep_on_writeback(inode); |
| /* Inode may be gone, start again */ |
| spin_lock(&wb->list_lock); |
| continue; |
| } |
| inode->i_state |= I_SYNC; |
| spin_unlock(&inode->i_lock); |
| |
| write_chunk = writeback_chunk_size(wb->bdi, work); |
| wbc.nr_to_write = write_chunk; |
| wbc.pages_skipped = 0; |
| |
| /* |
| * We use I_SYNC to pin the inode in memory. While it is set |
| * evict_inode() will wait so the inode cannot be freed. |
| */ |
| __writeback_single_inode(inode, &wbc); |
| |
| work->nr_pages -= write_chunk - wbc.nr_to_write; |
| wrote += write_chunk - wbc.nr_to_write; |
| spin_lock(&wb->list_lock); |
| spin_lock(&inode->i_lock); |
| if (!(inode->i_state & I_DIRTY)) |
| wrote++; |
| requeue_inode(inode, wb, &wbc); |
| inode_sync_complete(inode); |
| spin_unlock(&inode->i_lock); |
| cond_resched_lock(&wb->list_lock); |
| /* |
| * bail out to wb_writeback() often enough to check |
| * background threshold and other termination conditions. |
| */ |
| if (wrote) { |
| if (time_is_before_jiffies(start_time + HZ / 10UL)) |
| break; |
| if (work->nr_pages <= 0) |
| break; |
| } |
| } |
| return wrote; |
| } |
| |
| static long __writeback_inodes_wb(struct bdi_writeback *wb, |
| struct wb_writeback_work *work) |
| { |
| unsigned long start_time = jiffies; |
| long wrote = 0; |
| |
| while (!list_empty(&wb->b_io)) { |
| struct inode *inode = wb_inode(wb->b_io.prev); |
| struct super_block *sb = inode->i_sb; |
| |
| if (!grab_super_passive(sb)) { |
| /* |
| * grab_super_passive() may fail consistently due to |
| * s_umount being grabbed by someone else. Don't use |
| * requeue_io() to avoid busy retrying the inode/sb. |
| */ |
| redirty_tail(inode, wb); |
| continue; |
| } |
| wrote += writeback_sb_inodes(sb, wb, work); |
| drop_super(sb); |
| |
| /* refer to the same tests at the end of writeback_sb_inodes */ |
| if (wrote) { |
| if (time_is_before_jiffies(start_time + HZ / 10UL)) |
| break; |
| if (work->nr_pages <= 0) |
| break; |
| } |
| } |
| /* Leave any unwritten inodes on b_io */ |
| return wrote; |
| } |
| |
| static long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages, |
| enum wb_reason reason) |
| { |
| struct wb_writeback_work work = { |
| .nr_pages = nr_pages, |
| .sync_mode = WB_SYNC_NONE, |
| .range_cyclic = 1, |
| .reason = reason, |
| .older_than_this = jiffies, |
| .older_than_this_is_set = 1, |
| }; |
| |
| spin_lock(&wb->list_lock); |
| if (list_empty(&wb->b_io)) |
| queue_io(wb, &work); |
| __writeback_inodes_wb(wb, &work); |
| spin_unlock(&wb->list_lock); |
| |
| return nr_pages - work.nr_pages; |
| } |
| |
| static bool over_bground_thresh(struct backing_dev_info *bdi) |
| { |
| unsigned long background_thresh, dirty_thresh; |
| |
| global_dirty_limits(&background_thresh, &dirty_thresh); |
| |
| if (global_page_state(NR_FILE_DIRTY) + |
| global_page_state(NR_UNSTABLE_NFS) > background_thresh) |
| return true; |
| |
| if (bdi_stat(bdi, BDI_RECLAIMABLE) > |
| bdi_dirty_limit(bdi, background_thresh)) |
| return true; |
| |
| return false; |
| } |
| |
| /* |
| * Called under wb->list_lock. If there are multiple wb per bdi, |
| * only the flusher working on the first wb should do it. |
| */ |
| static void wb_update_bandwidth(struct bdi_writeback *wb, |
| unsigned long start_time) |
| { |
| __bdi_update_bandwidth(wb->bdi, 0, 0, 0, 0, 0, start_time); |
| } |
| |
| /* |
| * Explicit flushing or periodic writeback of "old" data. |
| * |
| * Define "old": the first time one of an inode's pages is dirtied, we mark the |
| * dirtying-time in the inode's address_space. So this periodic writeback code |
| * just walks the superblock inode list, writing back any inodes which are |
| * older than a specific point in time. |
| * |
| * Try to run once per dirty_writeback_interval. But if a writeback event |
| * takes longer than a dirty_writeback_interval interval, then leave a |
| * one-second gap. |
| * |
| * older_than_this takes precedence over nr_to_write. So we'll only write back |
| * all dirty pages if they are all attached to "old" mappings. |
| */ |
| static long wb_writeback(struct bdi_writeback *wb, |
| struct wb_writeback_work *work) |
| { |
| unsigned long wb_start = jiffies; |
| long nr_pages = work->nr_pages; |
| struct inode *inode; |
| long progress; |
| |
| if (!work->older_than_this_is_set) { |
| work->older_than_this = jiffies; |
| work->older_than_this_is_set = 1; |
| } |
| |
| spin_lock(&wb->list_lock); |
| for (;;) { |
| /* |
| * Stop writeback when nr_pages has been consumed |
| */ |
| if (work->nr_pages <= 0) |
| break; |
| |
| /* |
| * Background writeout and kupdate-style writeback may |
| * run forever. Stop them if there is other work to do |
| * so that e.g. sync can proceed. They'll be restarted |
| * after the other works are all done. |
| */ |
| if ((work->for_background || work->for_kupdate) && |
| !list_empty(&wb->bdi->work_list)) |
| break; |
| |
| /* |
| * For background writeout, stop when we are below the |
| * background dirty threshold |
| */ |
| if (work->for_background && !over_bground_thresh(wb->bdi)) |
| break; |
| |
| /* |
| * Kupdate and background works are special and we want to |
| * include all inodes that need writing. Livelock avoidance is |
| * handled by these works yielding to any other work so we are |
| * safe. |
| */ |
| if (work->for_kupdate) { |
| work->older_than_this = jiffies - |
| msecs_to_jiffies(dirty_expire_interval * 10); |
| } else if (work->for_background) |
| work->older_than_this = jiffies; |
| |
| trace_writeback_start(wb->bdi, work); |
| if (list_empty(&wb->b_io)) |
| queue_io(wb, work); |
| if (work->sb) |
| progress = writeback_sb_inodes(work->sb, wb, work); |
| else |
| progress = __writeback_inodes_wb(wb, work); |
| trace_writeback_written(wb->bdi, work); |
| |
| wb_update_bandwidth(wb, wb_start); |
| |
| /* |
| * Did we write something? Try for more |
| * |
| * Dirty inodes are moved to b_io for writeback in batches. |
| * The completion of the current batch does not necessarily |
| * mean the overall work is done. So we keep looping as long |
| * as made some progress on cleaning pages or inodes. |
| */ |
| if (progress) |
| continue; |
| /* |
| * No more inodes for IO, bail |
| */ |
| if (list_empty(&wb->b_more_io)) |
| break; |
| /* |
| * Nothing written. Wait for some inode to |
| * become available for writeback. Otherwise |
| * we'll just busyloop. |
| */ |
| if (!list_empty(&wb->b_more_io)) { |
| trace_writeback_wait(wb->bdi, work); |
| inode = wb_inode(wb->b_more_io.prev); |
| spin_lock(&inode->i_lock); |
| spin_unlock(&wb->list_lock); |
| /* This function drops i_lock... */ |
| inode_sleep_on_writeback(inode); |
| spin_lock(&wb->list_lock); |
| } |
| } |
| spin_unlock(&wb->list_lock); |
| |
| return nr_pages - work->nr_pages; |
| } |
| |
| /* |
| * Return the next wb_writeback_work struct that hasn't been processed yet. |
| */ |
| static struct wb_writeback_work * |
| get_next_work_item(struct backing_dev_info *bdi) |
| { |
| struct wb_writeback_work *work = NULL; |
| |
| spin_lock_bh(&bdi->wb_lock); |
| if (!list_empty(&bdi->work_list)) { |
| work = list_entry(bdi->work_list.next, |
| struct wb_writeback_work, list); |
| list_del_init(&work->list); |
| } |
| spin_unlock_bh(&bdi->wb_lock); |
| return work; |
| } |
| |
| /* |
| * Add in the number of potentially dirty inodes, because each inode |
| * write can dirty pagecache in the underlying blockdev. |
| */ |
| static unsigned long get_nr_dirty_pages(void) |
| { |
| return global_page_state(NR_FILE_DIRTY) + |
| global_page_state(NR_UNSTABLE_NFS) + |
| get_nr_dirty_inodes(); |
| } |
| |
| static long wb_check_background_flush(struct bdi_writeback *wb) |
| { |
| if (over_bground_thresh(wb->bdi)) { |
| |
| struct wb_writeback_work work = { |
| .nr_pages = LONG_MAX, |
| .sync_mode = WB_SYNC_NONE, |
| .for_background = 1, |
| .range_cyclic = 1, |
| .reason = WB_REASON_BACKGROUND, |
| }; |
| |
| return wb_writeback(wb, &work); |
| } |
| |
| return 0; |
| } |
| |
| static long wb_check_old_data_flush(struct bdi_writeback *wb) |
| { |
| unsigned long expired; |
| long nr_pages; |
| |
| /* |
| * When set to zero, disable periodic writeback |
| */ |
| if (!dirty_writeback_interval) |
| return 0; |
| |
| expired = wb->last_old_flush + |
| msecs_to_jiffies(dirty_writeback_interval * 10); |
| if (time_before(jiffies, expired)) |
| return 0; |
| |
| wb->last_old_flush = jiffies; |
| nr_pages = get_nr_dirty_pages(); |
| |
| if (nr_pages) { |
| struct wb_writeback_work work = { |
| .nr_pages = nr_pages, |
| .sync_mode = WB_SYNC_NONE, |
| .for_kupdate = 1, |
| .range_cyclic = 1, |
| .reason = WB_REASON_PERIODIC, |
| }; |
| |
| return wb_writeback(wb, &work); |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Retrieve work items and do the writeback they describe |
| */ |
| static long wb_do_writeback(struct bdi_writeback *wb) |
| { |
| struct backing_dev_info *bdi = wb->bdi; |
| struct wb_writeback_work *work; |
| long wrote = 0; |
| |
| set_bit(BDI_writeback_running, &wb->bdi->state); |
| while ((work = get_next_work_item(bdi)) != NULL) { |
| |
| trace_writeback_exec(bdi, work); |
| |
| wrote += wb_writeback(wb, work); |
| |
| /* |
| * Notify the caller of completion if this is a synchronous |
| * work item, otherwise just free it. |
| */ |
| if (work->done) |
| complete(work->done); |
| else |
| kfree(work); |
| } |
| |
| /* |
| * Check for periodic writeback, kupdated() style |
| */ |
| wrote += wb_check_old_data_flush(wb); |
| wrote += wb_check_background_flush(wb); |
| clear_bit(BDI_writeback_running, &wb->bdi->state); |
| |
| return wrote; |
| } |
| |
| /* |
| * Handle writeback of dirty data for the device backed by this bdi. Also |
| * reschedules periodically and does kupdated style flushing. |
| */ |
| void bdi_writeback_workfn(struct work_struct *work) |
| { |
| struct bdi_writeback *wb = container_of(to_delayed_work(work), |
| struct bdi_writeback, dwork); |
| struct backing_dev_info *bdi = wb->bdi; |
| long pages_written; |
| |
| set_worker_desc("flush-%s", dev_name(bdi->dev)); |
| current->flags |= PF_SWAPWRITE; |
| |
| if (likely(!current_is_workqueue_rescuer() || |
| list_empty(&bdi->bdi_list))) { |
| /* |
| * The normal path. Keep writing back @bdi until its |
| * work_list is empty. Note that this path is also taken |
| * if @bdi is shutting down even when we're running off the |
| * rescuer as work_list needs to be drained. |
| */ |
| do { |
| pages_written = wb_do_writeback(wb); |
| trace_writeback_pages_written(pages_written); |
| } while (!list_empty(&bdi->work_list)); |
| } else { |
| /* |
| * bdi_wq can't get enough workers and we're running off |
| * the emergency worker. Don't hog it. Hopefully, 1024 is |
| * enough for efficient IO. |
| */ |
| pages_written = writeback_inodes_wb(&bdi->wb, 1024, |
| WB_REASON_FORKER_THREAD); |
| trace_writeback_pages_written(pages_written); |
| } |
| |
| if (!list_empty(&bdi->work_list) || |
| (wb_has_dirty_io(wb) && dirty_writeback_interval)) |
| queue_delayed_work(bdi_wq, &wb->dwork, |
| msecs_to_jiffies(dirty_writeback_interval * 10)); |
| |
| current->flags &= ~PF_SWAPWRITE; |
| } |
| |
| /* |
| * Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back |
| * the whole world. |
| */ |
| void wakeup_flusher_threads(long nr_pages, enum wb_reason reason) |
| { |
| struct backing_dev_info *bdi; |
| |
| if (!nr_pages) |
| nr_pages = get_nr_dirty_pages(); |
| |
| rcu_read_lock(); |
| list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { |
| if (!bdi_has_dirty_io(bdi)) |
| continue; |
| __bdi_start_writeback(bdi, nr_pages, false, reason); |
| } |
| rcu_read_unlock(); |
| } |
| |
| static noinline void block_dump___mark_inode_dirty(struct inode *inode) |
| { |
| if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { |
| struct dentry *dentry; |
| const char *name = "?"; |
| |
| dentry = d_find_alias(inode); |
| if (dentry) { |
| spin_lock(&dentry->d_lock); |
| name = (const char *) dentry->d_name.name; |
| } |
| printk(KERN_DEBUG |
| "%s(%d): dirtied inode %lu (%s) on %s\n", |
| current->comm, task_pid_nr(current), inode->i_ino, |
| name, inode->i_sb->s_id); |
| if (dentry) { |
| spin_unlock(&dentry->d_lock); |
| dput(dentry); |
| } |
| } |
| } |
| |
| /** |
| * __mark_inode_dirty - internal function |
| * @inode: inode to mark |
| * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) |
| * Mark an inode as dirty. Callers should use mark_inode_dirty or |
| * mark_inode_dirty_sync. |
| * |
| * Put the inode on the super block's dirty list. |
| * |
| * CAREFUL! We mark it dirty unconditionally, but move it onto the |
| * dirty list only if it is hashed or if it refers to a blockdev. |
| * If it was not hashed, it will never be added to the dirty list |
| * even if it is later hashed, as it will have been marked dirty already. |
| * |
| * In short, make sure you hash any inodes _before_ you start marking |
| * them dirty. |
| * |
| * Note that for blockdevs, inode->dirtied_when represents the dirtying time of |
| * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of |
| * the kernel-internal blockdev inode represents the dirtying time of the |
| * blockdev's pages. This is why for I_DIRTY_PAGES we always use |
| * page->mapping->host, so the page-dirtying time is recorded in the internal |
| * blockdev inode. |
| */ |
| void __mark_inode_dirty(struct inode *inode, int flags) |
| { |
| struct super_block *sb = inode->i_sb; |
| struct backing_dev_info *bdi = NULL; |
| |
| /* |
| * Don't do this for I_DIRTY_PAGES - that doesn't actually |
| * dirty the inode itself |
| */ |
| if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { |
| trace_writeback_dirty_inode_start(inode, flags); |
| |
| if (sb->s_op->dirty_inode) |
| sb->s_op->dirty_inode(inode, flags); |
| |
| trace_writeback_dirty_inode(inode, flags); |
| } |
| |
| /* |
| * make sure that changes are seen by all cpus before we test i_state |
| * -- mikulas |
| */ |
| smp_mb(); |
| |
| /* avoid the locking if we can */ |
| if ((inode->i_state & flags) == flags) |
| return; |
| |
| if (unlikely(block_dump)) |
| block_dump___mark_inode_dirty(inode); |
| |
| spin_lock(&inode->i_lock); |
| if ((inode->i_state & flags) != flags) { |
| const int was_dirty = inode->i_state & I_DIRTY; |
| |
| inode->i_state |= flags; |
| |
| /* |
| * If the inode is being synced, just update its dirty state. |
| * The unlocker will place the inode on the appropriate |
| * superblock list, based upon its state. |
| */ |
| if (inode->i_state & I_SYNC) |
| goto out_unlock_inode; |
| |
| /* |
| * Only add valid (hashed) inodes to the superblock's |
| * dirty list. Add blockdev inodes as well. |
| */ |
| if (!S_ISBLK(inode->i_mode)) { |
| if (inode_unhashed(inode)) |
| goto out_unlock_inode; |
| } |
| if (inode->i_state & I_FREEING) |
| goto out_unlock_inode; |
| |
| /* |
| * If the inode was already on b_dirty/b_io/b_more_io, don't |
| * reposition it (that would break b_dirty time-ordering). |
| */ |
| if (!was_dirty) { |
| bool wakeup_bdi = false; |
| bdi = inode_to_bdi(inode); |
| |
| spin_unlock(&inode->i_lock); |
| spin_lock(&bdi->wb.list_lock); |
| if (bdi_cap_writeback_dirty(bdi)) { |
| WARN(!test_bit(BDI_registered, &bdi->state), |
| "bdi-%s not registered\n", bdi->name); |
| |
| /* |
| * If this is the first dirty inode for this |
| * bdi, we have to wake-up the corresponding |
| * bdi thread to make sure background |
| * write-back happens later. |
| */ |
| if (!wb_has_dirty_io(&bdi->wb)) |
| wakeup_bdi = true; |
| } |
| |
| inode->dirtied_when = jiffies; |
| list_move(&inode->i_wb_list, &bdi->wb.b_dirty); |
| spin_unlock(&bdi->wb.list_lock); |
| |
| if (wakeup_bdi) |
| bdi_wakeup_thread_delayed(bdi); |
| return; |
| } |
| } |
| out_unlock_inode: |
| spin_unlock(&inode->i_lock); |
| |
| } |
| EXPORT_SYMBOL(__mark_inode_dirty); |
| |
| static void wait_sb_inodes(struct super_block *sb) |
| { |
| struct inode *inode, *old_inode = NULL; |
| |
| /* |
| * We need to be protected against the filesystem going from |
| * r/o to r/w or vice versa. |
| */ |
| WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
| |
| spin_lock(&inode_sb_list_lock); |
| |
| /* |
| * Data integrity sync. Must wait for all pages under writeback, |
| * because there may have been pages dirtied before our sync |
| * call, but which had writeout started before we write it out. |
| * In which case, the inode may not be on the dirty list, but |
| * we still have to wait for that writeout. |
| */ |
| list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { |
| struct address_space *mapping = inode->i_mapping; |
| |
| spin_lock(&inode->i_lock); |
| if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) || |
| (mapping->nrpages == 0)) { |
| spin_unlock(&inode->i_lock); |
| continue; |
| } |
| __iget(inode); |
| spin_unlock(&inode->i_lock); |
| spin_unlock(&inode_sb_list_lock); |
| |
| /* |
| * We hold a reference to 'inode' so it couldn't have been |
| * removed from s_inodes list while we dropped the |
| * inode_sb_list_lock. We cannot iput the inode now as we can |
| * be holding the last reference and we cannot iput it under |
| * inode_sb_list_lock. So we keep the reference and iput it |
| * later. |
| */ |
| iput(old_inode); |
| old_inode = inode; |
| |
| filemap_fdatawait(mapping); |
| |
| cond_resched(); |
| |
| spin_lock(&inode_sb_list_lock); |
| } |
| spin_unlock(&inode_sb_list_lock); |
| iput(old_inode); |
| } |
| |
| /** |
| * writeback_inodes_sb_nr - writeback dirty inodes from given super_block |
| * @sb: the superblock |
| * @nr: the number of pages to write |
| * @reason: reason why some writeback work initiated |
| * |
| * Start writeback on some inodes on this super_block. No guarantees are made |
| * on how many (if any) will be written, and this function does not wait |
| * for IO completion of submitted IO. |
| */ |
| void writeback_inodes_sb_nr(struct super_block *sb, |
| unsigned long nr, |
| enum wb_reason reason) |
| { |
| DECLARE_COMPLETION_ONSTACK(done); |
| struct wb_writeback_work work = { |
| .sb = sb, |
| .sync_mode = WB_SYNC_NONE, |
| .tagged_writepages = 1, |
| .done = &done, |
| .nr_pages = nr, |
| .reason = reason, |
| }; |
| |
| if (sb->s_bdi == &noop_backing_dev_info) |
| return; |
| WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
| bdi_queue_work(sb->s_bdi, &work); |
| wait_for_completion(&done); |
| } |
| EXPORT_SYMBOL(writeback_inodes_sb_nr); |
| |
| /** |
| * writeback_inodes_sb - writeback dirty inodes from given super_block |
| * @sb: the superblock |
| * @reason: reason why some writeback work was initiated |
| * |
| * Start writeback on some inodes on this super_block. No guarantees are made |
| * on how many (if any) will be written, and this function does not wait |
| * for IO completion of submitted IO. |
| */ |
| void writeback_inodes_sb(struct super_block *sb, enum wb_reason reason) |
| { |
| return writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason); |
| } |
| EXPORT_SYMBOL(writeback_inodes_sb); |
| |
| /** |
| * try_to_writeback_inodes_sb_nr - try to start writeback if none underway |
| * @sb: the superblock |
| * @nr: the number of pages to write |
| * @reason: the reason of writeback |
| * |
| * Invoke writeback_inodes_sb_nr if no writeback is currently underway. |
| * Returns 1 if writeback was started, 0 if not. |
| */ |
| int try_to_writeback_inodes_sb_nr(struct super_block *sb, |
| unsigned long nr, |
| enum wb_reason reason) |
| { |
| if (writeback_in_progress(sb->s_bdi)) |
| return 1; |
| |
| if (!down_read_trylock(&sb->s_umount)) |
| return 0; |
| |
| writeback_inodes_sb_nr(sb, nr, reason); |
| up_read(&sb->s_umount); |
| return 1; |
| } |
| EXPORT_SYMBOL(try_to_writeback_inodes_sb_nr); |
| |
| /** |
| * try_to_writeback_inodes_sb - try to start writeback if none underway |
| * @sb: the superblock |
| * @reason: reason why some writeback work was initiated |
| * |
| * Implement by try_to_writeback_inodes_sb_nr() |
| * Returns 1 if writeback was started, 0 if not. |
| */ |
| int try_to_writeback_inodes_sb(struct super_block *sb, enum wb_reason reason) |
| { |
| return try_to_writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason); |
| } |
| EXPORT_SYMBOL(try_to_writeback_inodes_sb); |
| |
| /** |
| * sync_inodes_sb - sync sb inode pages |
| * @sb: the superblock |
| * @older_than_this: timestamp |
| * |
| * This function writes and waits on any dirty inode belonging to this |
| * superblock that has been dirtied before given timestamp. |
| */ |
| void sync_inodes_sb(struct super_block *sb, unsigned long older_than_this) |
| { |
| DECLARE_COMPLETION_ONSTACK(done); |
| struct wb_writeback_work work = { |
| .sb = sb, |
| .sync_mode = WB_SYNC_ALL, |
| .nr_pages = LONG_MAX, |
| .older_than_this = older_than_this, |
| .older_than_this_is_set = 1, |
| .range_cyclic = 0, |
| .done = &done, |
| .reason = WB_REASON_SYNC, |
| .for_sync = 1, |
| }; |
| |
| /* Nothing to do? */ |
| if (sb->s_bdi == &noop_backing_dev_info) |
| return; |
| WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
| |
| bdi_queue_work(sb->s_bdi, &work); |
| wait_for_completion(&done); |
| |
| wait_sb_inodes(sb); |
| } |
| EXPORT_SYMBOL(sync_inodes_sb); |
| |
| /** |
| * write_inode_now - write an inode to disk |
| * @inode: inode to write to disk |
| * @sync: whether the write should be synchronous or not |
| * |
| * This function commits an inode to disk immediately if it is dirty. This is |
| * primarily needed by knfsd. |
| * |
| * The caller must either have a ref on the inode or must have set I_WILL_FREE. |
| */ |
| int write_inode_now(struct inode *inode, int sync) |
| { |
| struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
| struct writeback_control wbc = { |
| .nr_to_write = LONG_MAX, |
| .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE, |
| .range_start = 0, |
| .range_end = LLONG_MAX, |
| }; |
| |
| if (!mapping_cap_writeback_dirty(inode->i_mapping)) |
| wbc.nr_to_write = 0; |
| |
| might_sleep(); |
| return writeback_single_inode(inode, wb, &wbc); |
| } |
| EXPORT_SYMBOL(write_inode_now); |
| |
| /** |
| * sync_inode - write an inode and its pages to disk. |
| * @inode: the inode to sync |
| * @wbc: controls the writeback mode |
| * |
| * sync_inode() will write an inode and its pages to disk. It will also |
| * correctly update the inode on its superblock's dirty inode lists and will |
| * update inode->i_state. |
| * |
| * The caller must have a ref on the inode. |
| */ |
| int sync_inode(struct inode *inode, struct writeback_control *wbc) |
| { |
| return writeback_single_inode(inode, &inode_to_bdi(inode)->wb, wbc); |
| } |
| EXPORT_SYMBOL(sync_inode); |
| |
| /** |
| * sync_inode_metadata - write an inode to disk |
| * @inode: the inode to sync |
| * @wait: wait for I/O to complete. |
| * |
| * Write an inode to disk and adjust its dirty state after completion. |
| * |
| * Note: only writes the actual inode, no associated data or other metadata. |
| */ |
| int sync_inode_metadata(struct inode *inode, int wait) |
| { |
| struct writeback_control wbc = { |
| .sync_mode = wait ? WB_SYNC_ALL : WB_SYNC_NONE, |
| .nr_to_write = 0, /* metadata-only */ |
| }; |
| |
| return sync_inode(inode, &wbc); |
| } |
| EXPORT_SYMBOL(sync_inode_metadata); |