From 7b7a8665edd8db733980389b098530f9e4f630b2 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 4 Sep 2013 15:04:39 +0200 Subject: direct-io: Implement generic deferred AIO completions Add support to the core direct-io code to defer AIO completions to user context using a workqueue. This replaces opencoded and less efficient code in XFS and ext4 (we save a memory allocation for each direct IO) and will be needed to properly support O_(D)SYNC for AIO. The communication between the filesystem and the direct I/O code requires a new buffer head flag, which is a bit ugly but not avoidable until the direct I/O code stops abusing the buffer_head structure for communicating with the filesystems. Currently this creates a per-superblock unbound workqueue for these completions, which is taken from an earlier patch by Jan Kara. I'm not really convinced about this use and would prefer a "normal" global workqueue with a high concurrency limit, but this needs further discussion. JK: Fixed ext4 part, dynamic allocation of the workqueue. Signed-off-by: Christoph Hellwig Signed-off-by: Jan Kara Signed-off-by: Al Viro --- fs/ext4/inode.c | 28 +++++++--------------------- 1 file changed, 7 insertions(+), 21 deletions(-) (limited to 'fs/ext4/inode.c') diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index c2ca04e67a4f..123bd81692d1 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -727,8 +727,12 @@ static int _ext4_get_block(struct inode *inode, sector_t iblock, ret = ext4_map_blocks(handle, inode, &map, flags); if (ret > 0) { + ext4_io_end_t *io_end = ext4_inode_aio(inode); + map_bh(bh, inode->i_sb, map.m_pblk); bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags; + if (io_end && io_end->flag & EXT4_IO_END_UNWRITTEN) + set_buffer_defer_completion(bh); bh->b_size = inode->i_sb->s_blocksize * map.m_len; ret = 0; } @@ -2991,19 +2995,13 @@ static int ext4_get_block_write_nolock(struct inode *inode, sector_t iblock, } static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset, - ssize_t size, void *private, int ret, - bool is_async) + ssize_t size, void *private) { - struct inode *inode = file_inode(iocb->ki_filp); ext4_io_end_t *io_end = iocb->private; /* if not async direct IO just return */ - if (!io_end) { - inode_dio_done(inode); - if (is_async) - aio_complete(iocb, ret, 0); + if (!io_end) return; - } ext_debug("ext4_end_io_dio(): io_end 0x%p " "for inode %lu, iocb 0x%p, offset %llu, size %zd\n", @@ -3013,11 +3011,7 @@ static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset, iocb->private = NULL; io_end->offset = offset; io_end->size = size; - if (is_async) { - io_end->iocb = iocb; - io_end->result = ret; - } - ext4_put_io_end_defer(io_end); + ext4_put_io_end(io_end); } /* @@ -3102,7 +3096,6 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb, ret = -ENOMEM; goto retake_lock; } - io_end->flag |= EXT4_IO_END_DIRECT; /* * Grab reference for DIO. Will be dropped in ext4_end_io_dio() */ @@ -3147,13 +3140,6 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb, if (ret <= 0 && ret != -EIOCBQUEUED && iocb->private) { WARN_ON(iocb->private != io_end); WARN_ON(io_end->flag & EXT4_IO_END_UNWRITTEN); - WARN_ON(io_end->iocb); - /* - * Generic code already did inode_dio_done() so we - * have to clear EXT4_IO_END_DIRECT to not do it for - * the second time. - */ - io_end->flag = 0; ext4_put_io_end(io_end); iocb->private = NULL; } -- cgit v1.2.3