X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=fs%2Fdirect-io.c;h=1782023bd68a6655d6def2258263d22080c06c33;hb=6c337ad6cccf3365c89152896217be9d953121c6;hp=7ab90f5081eebc4ab8b0de88bef8d0b6310ed113;hpb=188af63c0af2d7ef395bc94e3efa173f34dae03d;p=karo-tx-linux.git diff --git a/fs/direct-io.c b/fs/direct-io.c index 7ab90f5081ee..1782023bd68a 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -127,6 +127,7 @@ struct dio { spinlock_t bio_lock; /* protects BIO fields below */ int page_errors; /* errno from get_user_pages() */ int is_async; /* is IO async ? */ + bool defer_completion; /* defer AIO completion to workqueue? */ int io_error; /* IO error in completion path */ unsigned long refcount; /* direct_io_worker() and bios */ struct bio *bio_list; /* singly linked via bi_private */ @@ -141,7 +142,10 @@ struct dio { * allocation time. Don't add new fields after pages[] unless you * wish that they not be zeroed. */ - struct page *pages[DIO_PAGES]; /* page buffer */ + union { + struct page *pages[DIO_PAGES]; /* page buffer */ + struct work_struct complete_work;/* deferred AIO completion */ + }; } ____cacheline_aligned_in_smp; static struct kmem_cache *dio_cache __read_mostly; @@ -221,16 +225,16 @@ static inline struct page *dio_get_page(struct dio *dio, * dio_complete() - called when all DIO BIO I/O has been completed * @offset: the byte offset in the file of the completed operation * - * This releases locks as dictated by the locking type, lets interested parties - * know that a DIO operation has completed, and calculates the resulting return - * code for the operation. + * This drops i_dio_count, lets interested parties know that a DIO operation + * has completed, and calculates the resulting return code for the operation. * * It lets the filesystem know if it registered an interest earlier via * get_block. Pass the private field of the map buffer_head so that * filesystems can use it to hold additional state between get_block calls and * dio_complete. */ -static ssize_t dio_complete(struct dio *dio, loff_t offset, ssize_t ret, bool is_async) +static ssize_t dio_complete(struct dio *dio, loff_t offset, ssize_t ret, + bool is_async) { ssize_t transferred = 0; @@ -258,19 +262,36 @@ static ssize_t dio_complete(struct dio *dio, loff_t offset, ssize_t ret, bool is if (ret == 0) ret = transferred; - if (dio->end_io && dio->result) { - dio->end_io(dio->iocb, offset, transferred, - dio->private, ret, is_async); - } else { - inode_dio_done(dio->inode); - if (is_async) - aio_complete(dio->iocb, ret, 0); + if (dio->end_io && dio->result) + dio->end_io(dio->iocb, offset, transferred, dio->private); + + inode_dio_done(dio->inode); + if (is_async) { + if (dio->rw & WRITE) { + int err; + + err = generic_write_sync(dio->iocb->ki_filp, offset, + transferred); + if (err < 0 && ret > 0) + ret = err; + } + + aio_complete(dio->iocb, ret, 0); } + kmem_cache_free(dio_cache, dio); return ret; } +static void dio_aio_complete_work(struct work_struct *work) +{ + struct dio *dio = container_of(work, struct dio, complete_work); + + dio_complete(dio, dio->iocb->ki_pos, 0, true); +} + static int dio_bio_complete(struct dio *dio, struct bio *bio); + /* * Asynchronous IO callback. */ @@ -290,8 +311,13 @@ static void dio_bio_end_aio(struct bio *bio, int error) spin_unlock_irqrestore(&dio->bio_lock, flags); if (remaining == 0) { - dio_complete(dio, dio->iocb->ki_pos, 0, true); - kmem_cache_free(dio_cache, dio); + if (dio->result && dio->defer_completion) { + INIT_WORK(&dio->complete_work, dio_aio_complete_work); + queue_work(dio->inode->i_sb->s_dio_done_wq, + &dio->complete_work); + } else { + dio_complete(dio, dio->iocb->ki_pos, 0, true); + } } } @@ -510,6 +536,41 @@ static inline int dio_bio_reap(struct dio *dio, struct dio_submit *sdio) return ret; } +/* + * Create workqueue for deferred direct IO completions. We allocate the + * workqueue when it's first needed. This avoids creating workqueue for + * filesystems that don't need it and also allows us to create the workqueue + * late enough so the we can include s_id in the name of the workqueue. + */ +static int sb_init_dio_done_wq(struct super_block *sb) +{ + struct workqueue_struct *wq = alloc_workqueue("dio/%s", + WQ_MEM_RECLAIM, 0, + sb->s_id); + if (!wq) + return -ENOMEM; + /* + * This has to be atomic as more DIOs can race to create the workqueue + */ + cmpxchg(&sb->s_dio_done_wq, NULL, wq); + /* Someone created workqueue before us? Free ours... */ + if (wq != sb->s_dio_done_wq) + destroy_workqueue(wq); + return 0; +} + +static int dio_set_defer_completion(struct dio *dio) +{ + struct super_block *sb = dio->inode->i_sb; + + if (dio->defer_completion) + return 0; + dio->defer_completion = true; + if (!sb->s_dio_done_wq) + return sb_init_dio_done_wq(sb); + return 0; +} + /* * Call into the fs to map some more disk blocks. We record the current number * of available blocks at sdio->blocks_available. These are in units of the @@ -581,6 +642,9 @@ static int get_more_blocks(struct dio *dio, struct dio_submit *sdio, /* Store for completion */ dio->private = map_bh->b_private; + + if (ret == 0 && buffer_defer_completion(map_bh)) + ret = dio_set_defer_completion(dio); } return ret; } @@ -1128,11 +1192,6 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, } } - /* - * Will be decremented at I/O completion time. - */ - atomic_inc(&inode->i_dio_count); - /* * For file extending writes updating i_size before data * writeouts complete can expose uninitialized blocks. So @@ -1141,11 +1200,33 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, */ dio->is_async = !is_sync_kiocb(iocb) && !((rw & WRITE) && (end > i_size_read(inode))); - - retval = 0; - dio->inode = inode; dio->rw = rw; + + /* + * For AIO O_(D)SYNC writes we need to defer completions to a workqueue + * so that we can call ->fsync. + */ + if (dio->is_async && (rw & WRITE) && + ((iocb->ki_filp->f_flags & O_DSYNC) || + IS_SYNC(iocb->ki_filp->f_mapping->host))) { + retval = dio_set_defer_completion(dio); + if (retval) { + /* + * We grab i_mutex only for reads so we don't have + * to release it here + */ + kmem_cache_free(dio_cache, dio); + goto out; + } + } + + /* + * Will be decremented at I/O completion time. + */ + atomic_inc(&inode->i_dio_count); + + retval = 0; sdio.blkbits = blkbits; sdio.blkfactor = i_blkbits - blkbits; sdio.block_in_file = offset >> blkbits; @@ -1269,7 +1350,6 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, if (drop_refcount(dio) == 0) { retval = dio_complete(dio, offset, retval, false); - kmem_cache_free(dio_cache, dio); } else BUG_ON(retval != -EIOCBQUEUED);