From e917ff56c8e7b117b590632fa40a08e36577d31f Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 3 May 2023 09:06:14 +0200 Subject: [PATCH] btrfs: determine synchronous writers from bio or writeback control The writeback_control structure already passes down the information about a writeback being synchronous from the core VM code, and thus information is propagated into the bio REQ_SYNC flag through the wbc_to_write_flags helper. Use that information to decide if checksums calculation is offloaded to a workqueue instead of btrfs_inode::sync_writers field that not only bloats the inode but also has too wide scope, being inode wide instead of limited to the actual writeback request. The sync writes were set in: - btrfs_do_write_iter - regular IO, sync status is set - start_ordered_ops - ordered write start, writeback with WB_SYNC_ALL mode - btrfs_write_marked_extents - write marked extents, writeback with WB_SYNC_ALL mode Reviewed-by: Chris Mason Reviewed-by: Johannes Thumshirn Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba [ update changelog ] Signed-off-by: David Sterba --- fs/btrfs/bio.c | 7 +++---- fs/btrfs/btrfs_inode.h | 3 --- fs/btrfs/file.c | 9 --------- fs/btrfs/inode.c | 1 - fs/btrfs/transaction.c | 2 -- 5 files changed, 3 insertions(+), 19 deletions(-) diff --git a/fs/btrfs/bio.c b/fs/btrfs/bio.c index 67fb8f6a0eb9f..990a517c069be 100644 --- a/fs/btrfs/bio.c +++ b/fs/btrfs/bio.c @@ -579,11 +579,10 @@ static bool should_async_write(struct btrfs_bio *bbio) return false; /* - * If the I/O is not issued by fsync and friends, (->sync_writers != 0), - * then try to defer the submission to a workqueue to parallelize the - * checksum calculation. + * Try to defer the submission to a workqueue to parallelize the + * checksum calculation unless the I/O is issued synchronously. */ - if (atomic_read(&bbio->inode->sync_writers)) + if (op_is_sync(bbio->bio.bi_opf)) return false; /* Zoned devices require I/O to be submitted in order. */ diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h index ec2ae4406c16f..0849b85b94fe9 100644 --- a/fs/btrfs/btrfs_inode.h +++ b/fs/btrfs/btrfs_inode.h @@ -116,9 +116,6 @@ struct btrfs_inode { unsigned long runtime_flags; - /* Keep track of who's O_SYNC/fsyncing currently */ - atomic_t sync_writers; - /* full 64 bit generation number, struct vfs_inode doesn't have a big * enough field for this. */ diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index f649647392e0e..f53b7b75092db 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -1651,7 +1651,6 @@ ssize_t btrfs_do_write_iter(struct kiocb *iocb, struct iov_iter *from, struct file *file = iocb->ki_filp; struct btrfs_inode *inode = BTRFS_I(file_inode(file)); ssize_t num_written, num_sync; - const bool sync = iocb_is_dsync(iocb); /* * If the fs flips readonly due to some impossible error, although we @@ -1664,9 +1663,6 @@ ssize_t btrfs_do_write_iter(struct kiocb *iocb, struct iov_iter *from, if (encoded && (iocb->ki_flags & IOCB_NOWAIT)) return -EOPNOTSUPP; - if (sync) - atomic_inc(&inode->sync_writers); - if (encoded) { num_written = btrfs_encoded_write(iocb, from, encoded); num_sync = encoded->len; @@ -1686,9 +1682,6 @@ ssize_t btrfs_do_write_iter(struct kiocb *iocb, struct iov_iter *from, num_written = num_sync; } - if (sync) - atomic_dec(&inode->sync_writers); - current->backing_dev_info = NULL; return num_written; } @@ -1733,9 +1726,7 @@ static int start_ordered_ops(struct inode *inode, loff_t start, loff_t end) * several segments of stripe length (currently 64K). */ blk_start_plug(&plug); - atomic_inc(&BTRFS_I(inode)->sync_writers); ret = btrfs_fdatawrite_range(inode, start, end); - atomic_dec(&BTRFS_I(inode)->sync_writers); blk_finish_plug(&plug); return ret; diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index e6a21bbf40f2b..675b20c4d3c94 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -8468,7 +8468,6 @@ struct inode *btrfs_alloc_inode(struct super_block *sb) ei->io_tree.inode = ei; extent_io_tree_init(fs_info, &ei->file_extent_tree, IO_TREE_INODE_FILE_EXTENT); - atomic_set(&ei->sync_writers, 0); mutex_init(&ei->log_mutex); btrfs_ordered_inode_tree_init(&ei->ordered_tree); INIT_LIST_HEAD(&ei->delalloc_inodes); diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index 8b6a99b8d7f6d..27c616fdfae27 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -1056,7 +1056,6 @@ int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info, u64 start = 0; u64 end; - atomic_inc(&BTRFS_I(fs_info->btree_inode)->sync_writers); while (!find_first_extent_bit(dirty_pages, start, &start, &end, mark, &cached_state)) { bool wait_writeback = false; @@ -1092,7 +1091,6 @@ int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info, cond_resched(); start = end + 1; } - atomic_dec(&BTRFS_I(fs_info->btree_inode)->sync_writers); return werr; } -- 2.30.2