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Commit c77e9e68 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  writeback: simplify the write back thread queue
  writeback: split writeback_inodes_wb
  writeback: remove writeback_inodes_wbc
  fs-writeback: fix kernel-doc warnings
  splice: check f_mode for seekable file
  splice: direct_splice_actor() should not use pos in sd
parents 31016e99 83ba7b07
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+0 −1
Original line number Diff line number Diff line
@@ -680,7 +680,6 @@ int afs_writeback_all(struct afs_vnode *vnode)
{
	struct address_space *mapping = vnode->vfs_inode.i_mapping;
	struct writeback_control wbc = {
		.bdi		= mapping->backing_dev_info,
		.sync_mode	= WB_SYNC_ALL,
		.nr_to_write	= LONG_MAX,
		.range_cyclic	= 1,
+0 −2
Original line number Diff line number Diff line
@@ -2594,7 +2594,6 @@ int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
		.sync_io = wbc->sync_mode == WB_SYNC_ALL,
	};
	struct writeback_control wbc_writepages = {
		.bdi		= wbc->bdi,
		.sync_mode	= wbc->sync_mode,
		.older_than_this = NULL,
		.nr_to_write	= 64,
@@ -2628,7 +2627,6 @@ int extent_write_locked_range(struct extent_io_tree *tree, struct inode *inode,
		.sync_io = mode == WB_SYNC_ALL,
	};
	struct writeback_control wbc_writepages = {
		.bdi		= inode->i_mapping->backing_dev_info,
		.sync_mode	= mode,
		.older_than_this = NULL,
		.nr_to_write	= nr_pages * 2,
+111 −224
Original line number Diff line number Diff line
@@ -38,43 +38,18 @@ int nr_pdflush_threads;
/*
 * Passed into wb_writeback(), essentially a subset of writeback_control
 */
struct wb_writeback_args {
struct wb_writeback_work {
	long nr_pages;
	struct super_block *sb;
	enum writeback_sync_modes sync_mode;
	unsigned int for_kupdate:1;
	unsigned int range_cyclic:1;
	unsigned int for_background:1;
};

/*
 * Work items for the bdi_writeback threads
 */
struct bdi_work {
	struct list_head list;		/* pending work list */
	struct rcu_head rcu_head;	/* for RCU free/clear of work */

	unsigned long seen;		/* threads that have seen this work */
	atomic_t pending;		/* number of threads still to do work */

	struct wb_writeback_args args;	/* writeback arguments */

	unsigned long state;		/* flag bits, see WS_* */
};

enum {
	WS_INPROGRESS = 0,
	WS_ONSTACK,
	struct completion *done;	/* set if the caller waits */
};

static inline void bdi_work_init(struct bdi_work *work,
				 struct wb_writeback_args *args)
{
	INIT_RCU_HEAD(&work->rcu_head);
	work->args = *args;
	__set_bit(WS_INPROGRESS, &work->state);
}

/**
 * writeback_in_progress - determine whether there is writeback in progress
 * @bdi: the device's backing_dev_info structure.
@@ -87,49 +62,11 @@ int writeback_in_progress(struct backing_dev_info *bdi)
	return !list_empty(&bdi->work_list);
}

static void bdi_work_free(struct rcu_head *head)
{
	struct bdi_work *work = container_of(head, struct bdi_work, rcu_head);

	clear_bit(WS_INPROGRESS, &work->state);
	smp_mb__after_clear_bit();
	wake_up_bit(&work->state, WS_INPROGRESS);

	if (!test_bit(WS_ONSTACK, &work->state))
		kfree(work);
}

static void wb_clear_pending(struct bdi_writeback *wb, struct bdi_work *work)
{
	/*
	 * The caller has retrieved the work arguments from this work,
	 * drop our reference. If this is the last ref, delete and free it
	 */
	if (atomic_dec_and_test(&work->pending)) {
		struct backing_dev_info *bdi = wb->bdi;

		spin_lock(&bdi->wb_lock);
		list_del_rcu(&work->list);
		spin_unlock(&bdi->wb_lock);

		call_rcu(&work->rcu_head, bdi_work_free);
	}
}

static void bdi_queue_work(struct backing_dev_info *bdi, struct bdi_work *work)
static void bdi_queue_work(struct backing_dev_info *bdi,
		struct wb_writeback_work *work)
{
	work->seen = bdi->wb_mask;
	BUG_ON(!work->seen);
	atomic_set(&work->pending, bdi->wb_cnt);
	BUG_ON(!bdi->wb_cnt);

	/*
	 * list_add_tail_rcu() contains the necessary barriers to
	 * make sure the above stores are seen before the item is
	 * noticed on the list
	 */
	spin_lock(&bdi->wb_lock);
	list_add_tail_rcu(&work->list, &bdi->work_list);
	list_add_tail(&work->list, &bdi->work_list);
	spin_unlock(&bdi->wb_lock);

	/*
@@ -146,55 +83,29 @@ static void bdi_queue_work(struct backing_dev_info *bdi, struct bdi_work *work)
	}
}

/*
 * Used for on-stack allocated work items. The caller needs to wait until
 * the wb threads have acked the work before it's safe to continue.
 */
static void bdi_wait_on_work_done(struct bdi_work *work)
{
	wait_on_bit(&work->state, WS_INPROGRESS, bdi_sched_wait,
		    TASK_UNINTERRUPTIBLE);
}

static void bdi_alloc_queue_work(struct backing_dev_info *bdi,
				 struct wb_writeback_args *args)
static void
__bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
		bool range_cyclic, bool for_background)
{
	struct bdi_work *work;
	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 = kmalloc(sizeof(*work), GFP_ATOMIC);
	if (work) {
		bdi_work_init(work, args);
		bdi_queue_work(bdi, work);
	} else {
		struct bdi_writeback *wb = &bdi->wb;

		if (wb->task)
			wake_up_process(wb->task);
	}
	work = kzalloc(sizeof(*work), GFP_ATOMIC);
	if (!work) {
		if (bdi->wb.task)
			wake_up_process(bdi->wb.task);
		return;
	}

/**
 * bdi_queue_work_onstack - start and wait for writeback
 * @sb: write inodes from this super_block
 *
 * Description:
 *   This function initiates writeback and waits for the operation to
 *   complete. Callers must hold the sb s_umount semaphore for
 *   reading, to avoid having the super disappear before we are done.
 */
static void bdi_queue_work_onstack(struct wb_writeback_args *args)
{
	struct bdi_work work;

	bdi_work_init(&work, args);
	__set_bit(WS_ONSTACK, &work.state);
	work->sync_mode	= WB_SYNC_NONE;
	work->nr_pages	= nr_pages;
	work->range_cyclic = range_cyclic;
	work->for_background = for_background;

	bdi_queue_work(args->sb->s_bdi, &work);
	bdi_wait_on_work_done(&work);
	bdi_queue_work(bdi, work);
}

/**
@@ -210,13 +121,7 @@ static void bdi_queue_work_onstack(struct wb_writeback_args *args)
 */
void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages)
{
	struct wb_writeback_args args = {
		.sync_mode	= WB_SYNC_NONE,
		.nr_pages	= nr_pages,
		.range_cyclic	= 1,
	};

	bdi_alloc_queue_work(bdi, &args);
	__bdi_start_writeback(bdi, nr_pages, true, false);
}

/**
@@ -230,13 +135,7 @@ void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages)
 */
void bdi_start_background_writeback(struct backing_dev_info *bdi)
{
	struct wb_writeback_args args = {
		.sync_mode	= WB_SYNC_NONE,
		.nr_pages	= LONG_MAX,
		.for_background = 1,
		.range_cyclic	= 1,
	};
	bdi_alloc_queue_work(bdi, &args);
	__bdi_start_writeback(bdi, LONG_MAX, true, true);
}

/*
@@ -554,29 +453,41 @@ static bool pin_sb_for_writeback(struct super_block *sb)

/*
 * Write a portion of b_io inodes which belong to @sb.
 * If @wbc->sb != NULL, then find and write all such
 *
 * If @only_this_sb is true, then find and write all such
 * inodes. Otherwise write only ones which go sequentially
 * in reverse order.
 *
 * Return 1, if the caller writeback routine should be
 * interrupted. Otherwise return 0.
 */
static int writeback_sb_inodes(struct super_block *sb,
			       struct bdi_writeback *wb,
			       struct writeback_control *wbc)
static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
		struct writeback_control *wbc, bool only_this_sb)
{
	while (!list_empty(&wb->b_io)) {
		long pages_skipped;
		struct inode *inode = list_entry(wb->b_io.prev,
						 struct inode, i_list);
		if (wbc->sb && sb != inode->i_sb) {
			/* super block given and doesn't
			   match, skip this inode */

		if (inode->i_sb != sb) {
			if (only_this_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);
				continue;
			}
		if (sb != inode->i_sb)
			/* finish with this superblock */

			/*
			 * The inode belongs to a different superblock.
			 * Bounce back to the caller to unpin this and
			 * pin the next superblock.
			 */
			return 0;
		}

		if (inode->i_state & (I_NEW | I_WILL_FREE)) {
			requeue_io(inode);
			continue;
@@ -614,7 +525,7 @@ static int writeback_sb_inodes(struct super_block *sb,
	return 1;
}

static void writeback_inodes_wb(struct bdi_writeback *wb,
void writeback_inodes_wb(struct bdi_writeback *wb,
		struct writeback_control *wbc)
{
	int ret = 0;
@@ -629,29 +540,12 @@ static void writeback_inodes_wb(struct bdi_writeback *wb,
						 struct inode, i_list);
		struct super_block *sb = inode->i_sb;

		if (wbc->sb) {
			/*
			 * We are requested to write out inodes for a specific
			 * superblock.  This means we already have s_umount
			 * taken by the caller which also waits for us to
			 * complete the writeout.
			 */
			if (sb != wbc->sb) {
				redirty_tail(inode);
				continue;
			}

			WARN_ON(!rwsem_is_locked(&sb->s_umount));

			ret = writeback_sb_inodes(sb, wb, wbc);
		} else {
		if (!pin_sb_for_writeback(sb)) {
			requeue_io(inode);
			continue;
		}
			ret = writeback_sb_inodes(sb, wb, wbc);
		ret = writeback_sb_inodes(sb, wb, wbc, false);
		drop_super(sb);
		}

		if (ret)
			break;
@@ -660,11 +554,17 @@ static void writeback_inodes_wb(struct bdi_writeback *wb,
	/* Leave any unwritten inodes on b_io */
}

void writeback_inodes_wbc(struct writeback_control *wbc)
static void __writeback_inodes_sb(struct super_block *sb,
		struct bdi_writeback *wb, struct writeback_control *wbc)
{
	struct backing_dev_info *bdi = wbc->bdi;
	WARN_ON(!rwsem_is_locked(&sb->s_umount));

	writeback_inodes_wb(&bdi->wb, wbc);
	wbc->wb_start = jiffies; /* livelock avoidance */
	spin_lock(&inode_lock);
	if (!wbc->for_kupdate || list_empty(&wb->b_io))
		queue_io(wb, wbc->older_than_this);
	writeback_sb_inodes(sb, wb, wbc, true);
	spin_unlock(&inode_lock);
}

/*
@@ -702,16 +602,14 @@ static inline bool over_bground_thresh(void)
 * all dirty pages if they are all attached to "old" mappings.
 */
static long wb_writeback(struct bdi_writeback *wb,
			 struct wb_writeback_args *args)
			 struct wb_writeback_work *work)
{
	struct writeback_control wbc = {
		.bdi			= wb->bdi,
		.sb			= args->sb,
		.sync_mode		= args->sync_mode,
		.sync_mode		= work->sync_mode,
		.older_than_this	= NULL,
		.for_kupdate		= args->for_kupdate,
		.for_background		= args->for_background,
		.range_cyclic		= args->range_cyclic,
		.for_kupdate		= work->for_kupdate,
		.for_background		= work->for_background,
		.range_cyclic		= work->range_cyclic,
	};
	unsigned long oldest_jif;
	long wrote = 0;
@@ -731,21 +629,24 @@ static long wb_writeback(struct bdi_writeback *wb,
		/*
		 * Stop writeback when nr_pages has been consumed
		 */
		if (args->nr_pages <= 0)
		if (work->nr_pages <= 0)
			break;

		/*
		 * For background writeout, stop when we are below the
		 * background dirty threshold
		 */
		if (args->for_background && !over_bground_thresh())
		if (work->for_background && !over_bground_thresh())
			break;

		wbc.more_io = 0;
		wbc.nr_to_write = MAX_WRITEBACK_PAGES;
		wbc.pages_skipped = 0;
		if (work->sb)
			__writeback_inodes_sb(work->sb, wb, &wbc);
		else
			writeback_inodes_wb(wb, &wbc);
		args->nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write;
		work->nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write;
		wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write;

		/*
@@ -781,31 +682,21 @@ static long wb_writeback(struct bdi_writeback *wb,
}

/*
 * Return the next bdi_work struct that hasn't been processed by this
 * wb thread yet. ->seen is initially set for each thread that exists
 * for this device, when a thread first notices a piece of work it
 * clears its bit. Depending on writeback type, the thread will notify
 * completion on either receiving the work (WB_SYNC_NONE) or after
 * it is done (WB_SYNC_ALL).
 */
static struct bdi_work *get_next_work_item(struct backing_dev_info *bdi,
					   struct bdi_writeback *wb)
 * 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 bdi_writeback *wb)
{
	struct bdi_work *work, *ret = NULL;

	rcu_read_lock();
	struct wb_writeback_work *work = NULL;

	list_for_each_entry_rcu(work, &bdi->work_list, list) {
		if (!test_bit(wb->nr, &work->seen))
			continue;
		clear_bit(wb->nr, &work->seen);

		ret = work;
		break;
	spin_lock(&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);
	}

	rcu_read_unlock();
	return ret;
	spin_unlock(&bdi->wb_lock);
	return work;
}

static long wb_check_old_data_flush(struct bdi_writeback *wb)
@@ -830,14 +721,14 @@ static long wb_check_old_data_flush(struct bdi_writeback *wb)
			(inodes_stat.nr_inodes - inodes_stat.nr_unused);

	if (nr_pages) {
		struct wb_writeback_args args = {
		struct wb_writeback_work work = {
			.nr_pages	= nr_pages,
			.sync_mode	= WB_SYNC_NONE,
			.for_kupdate	= 1,
			.range_cyclic	= 1,
		};

		return wb_writeback(wb, &args);
		return wb_writeback(wb, &work);
	}

	return 0;
@@ -849,33 +740,27 @@ static long wb_check_old_data_flush(struct bdi_writeback *wb)
long wb_do_writeback(struct bdi_writeback *wb, int force_wait)
{
	struct backing_dev_info *bdi = wb->bdi;
	struct bdi_work *work;
	struct wb_writeback_work *work;
	long wrote = 0;

	while ((work = get_next_work_item(bdi, wb)) != NULL) {
		struct wb_writeback_args args = work->args;

		/*
		 * Override sync mode, in case we must wait for completion
		 * because this thread is exiting now.
		 */
		if (force_wait)
			work->args.sync_mode = args.sync_mode = WB_SYNC_ALL;
			work->sync_mode = WB_SYNC_ALL;

		/*
		 * If this isn't a data integrity operation, just notify
		 * that we have seen this work and we are now starting it.
		 */
		if (!test_bit(WS_ONSTACK, &work->state))
			wb_clear_pending(wb, work);

		wrote += wb_writeback(wb, &args);
		wrote += wb_writeback(wb, work);

		/*
		 * This is a data integrity writeback, so only do the
		 * notification when we have completed the work.
		 * Notify the caller of completion if this is a synchronous
		 * work item, otherwise just free it.
		 */
		if (test_bit(WS_ONSTACK, &work->state))
			wb_clear_pending(wb, work);
		if (work->done)
			complete(work->done);
		else
			kfree(work);
	}

	/*
@@ -938,14 +823,9 @@ int bdi_writeback_task(struct bdi_writeback *wb)
void wakeup_flusher_threads(long nr_pages)
{
	struct backing_dev_info *bdi;
	struct wb_writeback_args args = {
		.sync_mode	= WB_SYNC_NONE,
	};

	if (nr_pages) {
		args.nr_pages = nr_pages;
	} else {
		args.nr_pages = global_page_state(NR_FILE_DIRTY) +
	if (!nr_pages) {
		nr_pages = global_page_state(NR_FILE_DIRTY) +
				global_page_state(NR_UNSTABLE_NFS);
	}

@@ -953,7 +833,7 @@ void wakeup_flusher_threads(long nr_pages)
	list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) {
		if (!bdi_has_dirty_io(bdi))
			continue;
		bdi_alloc_queue_work(bdi, &args);
		__bdi_start_writeback(bdi, nr_pages, false, false);
	}
	rcu_read_unlock();
}
@@ -1162,17 +1042,20 @@ void writeback_inodes_sb(struct super_block *sb)
{
	unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY);
	unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS);
	struct wb_writeback_args args = {
	DECLARE_COMPLETION_ONSTACK(done);
	struct wb_writeback_work work = {
		.sb		= sb,
		.sync_mode	= WB_SYNC_NONE,
		.done		= &done,
	};

	WARN_ON(!rwsem_is_locked(&sb->s_umount));

	args.nr_pages = nr_dirty + nr_unstable +
	work.nr_pages = nr_dirty + nr_unstable +
			(inodes_stat.nr_inodes - inodes_stat.nr_unused);

	bdi_queue_work_onstack(&args);
	bdi_queue_work(sb->s_bdi, &work);
	wait_for_completion(&done);
}
EXPORT_SYMBOL(writeback_inodes_sb);

@@ -1204,16 +1087,20 @@ EXPORT_SYMBOL(writeback_inodes_sb_if_idle);
 */
void sync_inodes_sb(struct super_block *sb)
{
	struct wb_writeback_args args = {
	DECLARE_COMPLETION_ONSTACK(done);
	struct wb_writeback_work work = {
		.sb		= sb,
		.sync_mode	= WB_SYNC_ALL,
		.nr_pages	= LONG_MAX,
		.range_cyclic	= 0,
		.done		= &done,
	};

	WARN_ON(!rwsem_is_locked(&sb->s_umount));

	bdi_queue_work_onstack(&args);
	bdi_queue_work(sb->s_bdi, &work);
	wait_for_completion(&done);

	wait_sb_inodes(sb);
}
EXPORT_SYMBOL(sync_inodes_sb);
+4 −5
Original line number Diff line number Diff line
@@ -1282,7 +1282,8 @@ static int direct_splice_actor(struct pipe_inode_info *pipe,
{
	struct file *file = sd->u.file;

	return do_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags);
	return do_splice_from(pipe, file, &file->f_pos, sd->total_len,
			      sd->flags);
}

/**
@@ -1371,8 +1372,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
		if (off_in)
			return -ESPIPE;
		if (off_out) {
			if (!out->f_op || !out->f_op->llseek ||
			    out->f_op->llseek == no_llseek)
			if (!(out->f_mode & FMODE_PWRITE))
				return -EINVAL;
			if (copy_from_user(&offset, off_out, sizeof(loff_t)))
				return -EFAULT;
@@ -1392,8 +1392,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
		if (off_out)
			return -ESPIPE;
		if (off_in) {
			if (!in->f_op || !in->f_op->llseek ||
			    in->f_op->llseek == no_llseek)
			if (!(in->f_mode & FMODE_PREAD))
				return -EINVAL;
			if (copy_from_user(&offset, off_in, sizeof(loff_t)))
				return -EFAULT;
+0 −2
Original line number Diff line number Diff line
@@ -82,8 +82,6 @@ struct backing_dev_info {
	struct bdi_writeback wb;  /* default writeback info for this bdi */
	spinlock_t wb_lock;	  /* protects update side of wb_list */
	struct list_head wb_list; /* the flusher threads hanging off this bdi */
	unsigned long wb_mask;	  /* bitmask of registered tasks */
	unsigned int wb_cnt;	  /* number of registered tasks */

	struct list_head work_list;

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