Add buffer head related helper functions (389d1b08) · Commits · 戴 / test

fs/buffer.c

+44 −0

Original line number	Diff line number	Diff line
		@@ -3213,6 +3213,50 @@ static int buffer_cpu_notify(struct notifier_block *self,
		return NOTIFY_OK;
		}

		/**
		* bh_uptodate_or_lock: Test whether the buffer is uptodate
		* @bh: struct buffer_head
		*
		* Return true if the buffer is up-to-date and false,
		* with the buffer locked, if not.
		*/
		int bh_uptodate_or_lock(struct buffer_head *bh)
		{
		if (!buffer_uptodate(bh)) {
		lock_buffer(bh);
		if (!buffer_uptodate(bh))
		return 0;
		unlock_buffer(bh);
		}
		return 1;
		}
		EXPORT_SYMBOL(bh_uptodate_or_lock);

		/**
		* bh_submit_read: Submit a locked buffer for reading
		* @bh: struct buffer_head
		*
		* Returns zero on success and -EIO on error.
		*/
		int bh_submit_read(struct buffer_head *bh)
		{
		BUG_ON(!buffer_locked(bh));

		if (buffer_uptodate(bh)) {
		unlock_buffer(bh);
		return 0;
		}

		get_bh(bh);
		bh->b_end_io = end_buffer_read_sync;
		submit_bh(READ, bh);
		wait_on_buffer(bh);
		if (buffer_uptodate(bh))
		return 0;
		return -EIO;
		}
		EXPORT_SYMBOL(bh_submit_read);

		void __init buffer_init(void)
		{
		int nrpages;

+2 −0

Original line number	Diff line number	Diff line
		@@ -192,6 +192,8 @@ int sync_dirty_buffer(struct buffer_head *bh);
		int submit_bh(int, struct buffer_head *);
		void write_boundary_block(struct block_device *bdev,
		sector_t bblock, unsigned blocksize);
		int bh_uptodate_or_lock(struct buffer_head *bh);
		int bh_submit_read(struct buffer_head *bh);

		extern int buffer_heads_over_limit;