From 3f666c56c6b8cc40a5e9002aac484b8f5b83c402 Mon Sep 17 00:00:00 2001 From: Vivek Goyal Date: Fri, 3 Jan 2020 13:33:07 -0500 Subject: [PATCH 1/3] dax: Pass dax_dev instead of bdev to dax_writeback_mapping_range() As of now dax_writeback_mapping_range() takes "struct block_device" as a parameter and dax_dev is searched from bdev name. This also involves taking a fresh reference on dax_dev and putting that reference at the end of function. We are developing a new filesystem virtio-fs and using dax to access host page cache directly. But there is no block device. IOW, we want to make use of dax but want to get rid of this assumption that there is always a block device associated with dax_dev. So pass in "struct dax_device" as parameter instead of bdev. ext2/ext4/xfs are current users and they already have a reference on dax_device. So there is no need to take reference and drop reference to dax_device on each call of this function. Suggested-by: Christoph Hellwig Reviewed-by: Christoph Hellwig Reviewed-by: Jan Kara Signed-off-by: Vivek Goyal Link: https://lore.kernel.org/r/20200103183307.GB13350@redhat.com Signed-off-by: Dan Williams --- fs/dax.c | 8 +------- fs/ext2/inode.c | 5 +++-- fs/ext4/inode.c | 2 +- fs/xfs/xfs_aops.c | 2 +- include/linux/dax.h | 4 ++-- 5 files changed, 8 insertions(+), 13 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index 1f1f0201cad182..1a64c19de0ad0c 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -937,12 +937,11 @@ static int dax_writeback_one(struct xa_state *xas, struct dax_device *dax_dev, * on persistent storage prior to completion of the operation. */ int dax_writeback_mapping_range(struct address_space *mapping, - struct block_device *bdev, struct writeback_control *wbc) + struct dax_device *dax_dev, struct writeback_control *wbc) { XA_STATE(xas, &mapping->i_pages, wbc->range_start >> PAGE_SHIFT); struct inode *inode = mapping->host; pgoff_t end_index = wbc->range_end >> PAGE_SHIFT; - struct dax_device *dax_dev; void *entry; int ret = 0; unsigned int scanned = 0; @@ -953,10 +952,6 @@ int dax_writeback_mapping_range(struct address_space *mapping, if (!mapping->nrexceptional || wbc->sync_mode != WB_SYNC_ALL) return 0; - dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); - if (!dax_dev) - return -EIO; - trace_dax_writeback_range(inode, xas.xa_index, end_index); tag_pages_for_writeback(mapping, xas.xa_index, end_index); @@ -977,7 +972,6 @@ int dax_writeback_mapping_range(struct address_space *mapping, xas_lock_irq(&xas); } xas_unlock_irq(&xas); - put_dax(dax_dev); trace_dax_writeback_range_done(inode, xas.xa_index, end_index); return ret; } diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c index 119667e658904a..c885cf7d724b48 100644 --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c @@ -960,8 +960,9 @@ ext2_writepages(struct address_space *mapping, struct writeback_control *wbc) static int ext2_dax_writepages(struct address_space *mapping, struct writeback_control *wbc) { - return dax_writeback_mapping_range(mapping, - mapping->host->i_sb->s_bdev, wbc); + struct ext2_sb_info *sbi = EXT2_SB(mapping->host->i_sb); + + return dax_writeback_mapping_range(mapping, sbi->s_daxdev, wbc); } const struct address_space_operations ext2_aops = { diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 28f28de0c1b67e..9992af776fbd3f 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2866,7 +2866,7 @@ static int ext4_dax_writepages(struct address_space *mapping, percpu_down_read(&sbi->s_journal_flag_rwsem); trace_ext4_writepages(inode, wbc); - ret = dax_writeback_mapping_range(mapping, inode->i_sb->s_bdev, wbc); + ret = dax_writeback_mapping_range(mapping, sbi->s_daxdev, wbc); trace_ext4_writepages_result(inode, wbc, ret, nr_to_write - wbc->nr_to_write); percpu_up_read(&sbi->s_journal_flag_rwsem); diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index 3a688eb5c5ae4e..58e937be24cee7 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -587,7 +587,7 @@ xfs_dax_writepages( xfs_iflags_clear(ip, XFS_ITRUNCATED); return dax_writeback_mapping_range(mapping, - xfs_inode_buftarg(ip)->bt_bdev, wbc); + xfs_inode_buftarg(ip)->bt_daxdev, wbc); } STATIC sector_t diff --git a/include/linux/dax.h b/include/linux/dax.h index 9bd8528bd305f1..d5932e47c59747 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -141,7 +141,7 @@ static inline void fs_put_dax(struct dax_device *dax_dev) struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev); int dax_writeback_mapping_range(struct address_space *mapping, - struct block_device *bdev, struct writeback_control *wbc); + struct dax_device *dax_dev, struct writeback_control *wbc); struct page *dax_layout_busy_page(struct address_space *mapping); dax_entry_t dax_lock_page(struct page *page); @@ -180,7 +180,7 @@ static inline struct page *dax_layout_busy_page(struct address_space *mapping) } static inline int dax_writeback_mapping_range(struct address_space *mapping, - struct block_device *bdev, struct writeback_control *wbc) + struct dax_device *dax_dev, struct writeback_control *wbc) { return -EOPNOTSUPP; } From f01b16a85bfae2e6b4f32de0a1f37ac4050dc316 Mon Sep 17 00:00:00 2001 From: Vivek Goyal Date: Mon, 6 Jan 2020 13:11:17 -0500 Subject: [PATCH 2/3] dax: Get rid of fs_dax_get_by_host() helper Looks like nobody is using fs_dax_get_by_host() except fs_dax_get_by_bdev() and it can easily use dax_get_by_host() instead. IIUC, fs_dax_get_by_host() was only introduced so that one could compile with CONFIG_FS_DAX=n and CONFIG_DAX=m. fs_dax_get_by_bdev() achieves the same purpose and hence it looks like fs_dax_get_by_host() is not needed anymore. Signed-off-by: Vivek Goyal Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20200106181117.GA16248@redhat.com Signed-off-by: Dan Williams --- drivers/dax/super.c | 2 +- include/linux/dax.h | 10 ---------- 2 files changed, 1 insertion(+), 11 deletions(-) diff --git a/drivers/dax/super.c b/drivers/dax/super.c index 26a654dbc69a26..0aa4b6bc5101dc 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -61,7 +61,7 @@ struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) { if (!blk_queue_dax(bdev->bd_queue)) return NULL; - return fs_dax_get_by_host(bdev->bd_disk->disk_name); + return dax_get_by_host(bdev->bd_disk->disk_name); } EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); #endif diff --git a/include/linux/dax.h b/include/linux/dax.h index d5932e47c59747..328c2dbb4409ce 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -129,11 +129,6 @@ static inline bool generic_fsdax_supported(struct dax_device *dax_dev, sectors); } -static inline struct dax_device *fs_dax_get_by_host(const char *host) -{ - return dax_get_by_host(host); -} - static inline void fs_put_dax(struct dax_device *dax_dev) { put_dax(dax_dev); @@ -160,11 +155,6 @@ static inline bool generic_fsdax_supported(struct dax_device *dax_dev, return false; } -static inline struct dax_device *fs_dax_get_by_host(const char *host) -{ - return NULL; -} - static inline void fs_put_dax(struct dax_device *dax_dev) { } From 96222d53842dfe54869ec4e1b9d4856daf9105a2 Mon Sep 17 00:00:00 2001 From: Jeff Moyer Date: Wed, 5 Feb 2020 14:15:58 -0500 Subject: [PATCH 3/3] dax: pass NOWAIT flag to iomap_apply fstests generic/471 reports a failure when run with MOUNT_OPTIONS="-o dax". The reason is that the initial pwrite to an empty file with the RWF_NOWAIT flag set does not return -EAGAIN. It turns out that dax_iomap_rw doesn't pass that flag through to iomap_apply. With this patch applied, generic/471 passes for me. Signed-off-by: Jeff Moyer Reviewed-by: Christoph Hellwig Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/x49r1z86e1d.fsf@segfault.boston.devel.redhat.com Signed-off-by: Dan Williams --- fs/dax.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/dax.c b/fs/dax.c index 1a64c19de0ad0c..35da144375a0ad 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1201,6 +1201,9 @@ dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, lockdep_assert_held(&inode->i_rwsem); } + if (iocb->ki_flags & IOCB_NOWAIT) + flags |= IOMAP_NOWAIT; + while (iov_iter_count(iter)) { ret = iomap_apply(inode, pos, iov_iter_count(iter), flags, ops, iter, dax_iomap_actor);