From 0bd2d5ec3d7655a849928f04597a0ceea0329176 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Sun, 20 Nov 2016 18:53:30 -0500 Subject: [PATCH] ext4: rip out DAX handling from direct IO path Reads and writes for DAX inodes should no longer end up in direct IO code. Rip out the support and add a warning. Reviewed-by: Ross Zwisler Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o --- fs/ext4/ext4.h | 2 -- fs/ext4/inode.c | 97 +++++++++------------------------------------------------ 2 files changed, 15 insertions(+), 84 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index da82de650..6673e88 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2452,8 +2452,6 @@ struct buffer_head *ext4_getblk(handle_t *, struct inode *, ext4_lblk_t, int); struct buffer_head *ext4_bread(handle_t *, struct inode *, ext4_lblk_t, int); int ext4_get_block_unwritten(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create); -int ext4_dax_get_block(struct inode *inode, sector_t iblock, - struct buffer_head *bh_result, int create); int ext4_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create); int ext4_dio_get_block(struct inode *inode, sector_t iblock, diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 9de9a5a..861f848 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3280,46 +3280,6 @@ static int ext4_releasepage(struct page *page, gfp_t wait) } #ifdef CONFIG_FS_DAX -/* - * Get block function for DAX IO and mmap faults. It takes care of converting - * unwritten extents to written ones and initializes new / converted blocks - * to zeros. - */ -int ext4_dax_get_block(struct inode *inode, sector_t iblock, - struct buffer_head *bh_result, int create) -{ - int ret; - - ext4_debug("inode %lu, create flag %d\n", inode->i_ino, create); - if (!create) - return _ext4_get_block(inode, iblock, bh_result, 0); - - ret = ext4_get_block_trans(inode, iblock, bh_result, - EXT4_GET_BLOCKS_PRE_IO | - EXT4_GET_BLOCKS_CREATE_ZERO); - if (ret < 0) - return ret; - - if (buffer_unwritten(bh_result)) { - /* - * We are protected by i_mmap_sem or i_mutex so we know block - * cannot go away from under us even though we dropped - * i_data_sem. Convert extent to written and write zeros there. - */ - ret = ext4_get_block_trans(inode, iblock, bh_result, - EXT4_GET_BLOCKS_CONVERT | - EXT4_GET_BLOCKS_CREATE_ZERO); - if (ret < 0) - return ret; - } - /* - * At least for now we have to clear BH_New so that DAX code - * doesn't attempt to zero blocks again in a racy way. - */ - clear_buffer_new(bh_result); - return 0; -} - static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, unsigned flags, struct iomap *iomap) { @@ -3473,14 +3433,6 @@ struct iomap_ops ext4_iomap_ops = { .iomap_end = ext4_iomap_end, }; -#else -/* Just define empty function, it will never get called. */ -int ext4_dax_get_block(struct inode *inode, sector_t iblock, - struct buffer_head *bh_result, int create) -{ - BUG(); - return 0; -} #endif static int ext4_end_io_dio(struct kiocb *iocb, loff_t offset, @@ -3602,19 +3554,7 @@ static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter) iocb->private = NULL; if (overwrite) get_block_func = ext4_dio_get_block_overwrite; - else if (IS_DAX(inode)) { - /* - * We can avoid zeroing for aligned DAX writes beyond EOF. Other - * writes need zeroing either because they can race with page - * faults or because they use partial blocks. - */ - if (round_down(offset, 1<i_blkbits) >= inode->i_size && - ext4_aligned_io(inode, offset, count)) - get_block_func = ext4_dio_get_block; - else - get_block_func = ext4_dax_get_block; - dio_flags = DIO_LOCKING; - } else if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) || + else if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) || round_down(offset, 1 << inode->i_blkbits) >= inode->i_size) { get_block_func = ext4_dio_get_block; dio_flags = DIO_LOCKING | DIO_SKIP_HOLES; @@ -3628,14 +3568,9 @@ static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter) #ifdef CONFIG_EXT4_FS_ENCRYPTION BUG_ON(ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode)); #endif - if (IS_DAX(inode)) { - ret = dax_do_io(iocb, inode, iter, get_block_func, - ext4_end_io_dio, dio_flags); - } else - ret = __blockdev_direct_IO(iocb, inode, - inode->i_sb->s_bdev, iter, - get_block_func, - ext4_end_io_dio, NULL, dio_flags); + ret = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter, + get_block_func, ext4_end_io_dio, NULL, + dio_flags); if (ret > 0 && !overwrite && ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN)) { @@ -3704,6 +3639,7 @@ static ssize_t ext4_direct_IO_read(struct kiocb *iocb, struct iov_iter *iter) { struct address_space *mapping = iocb->ki_filp->f_mapping; struct inode *inode = mapping->host; + size_t count = iov_iter_count(iter); ssize_t ret; /* @@ -3712,19 +3648,12 @@ static ssize_t ext4_direct_IO_read(struct kiocb *iocb, struct iov_iter *iter) * we are protected against page writeback as well. */ inode_lock_shared(inode); - if (IS_DAX(inode)) { - ret = dax_do_io(iocb, inode, iter, ext4_dio_get_block, NULL, 0); - } else { - size_t count = iov_iter_count(iter); - - ret = filemap_write_and_wait_range(mapping, iocb->ki_pos, - iocb->ki_pos + count); - if (ret) - goto out_unlock; - ret = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, - iter, ext4_dio_get_block, - NULL, NULL, 0); - } + ret = filemap_write_and_wait_range(mapping, iocb->ki_pos, + iocb->ki_pos + count); + if (ret) + goto out_unlock; + ret = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, + iter, ext4_dio_get_block, NULL, NULL, 0); out_unlock: inode_unlock_shared(inode); return ret; @@ -3753,6 +3682,10 @@ static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter) if (ext4_has_inline_data(inode)) return 0; + /* DAX uses iomap path now */ + if (WARN_ON_ONCE(IS_DAX(inode))) + return 0; + trace_ext4_direct_IO_enter(inode, offset, count, iov_iter_rw(iter)); if (iov_iter_rw(iter) == READ) ret = ext4_direct_IO_read(iocb, iter); -- 2.7.4