Commit 3fc37253 authored by Dan Williams's avatar Dan Williams
Browse files

Merge branch 'for-5.15/fsdax-cleanups' into for-5.15/libnvdimm 

Include Christoph's rework of the dax_supported() helpers in the v5.15
libnvdimm update. This supports the ongoing dax-reflink enabling effort.
parents 32b2397c bdd3c50d

drivers/dax/super.c

+73 −118
Original line number Diff line number Diff line
@@ -17,6 +17,24 @@ 
#include <linux/fs.h>

#include "dax-private.h"



/**

 * struct dax_device - anchor object for dax services

 * @inode: core vfs

 * @cdev: optional character interface for "device dax"

 * @host: optional name for lookups where the device path is not available

 * @private: dax driver private data

 * @flags: state and boolean properties

 */

struct dax_device {

	struct hlist_node list;

	struct inode inode;

	struct cdev cdev;

	const char *host;

	void *private;

	unsigned long flags;

	const struct dax_operations *ops;

};



static dev_t dax_devt;

DEFINE_STATIC_SRCU(dax_srcu);

static struct vfsmount *dax_mnt;
@@ -40,6 +58,42 @@ void dax_read_unlock(int id) 
}

EXPORT_SYMBOL_GPL(dax_read_unlock);



static int dax_host_hash(const char *host)

{

	return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE;

}



/**

 * dax_get_by_host() - temporary lookup mechanism for filesystem-dax

 * @host: alternate name for the device registered by a dax driver

 */

static struct dax_device *dax_get_by_host(const char *host)

{

	struct dax_device *dax_dev, *found = NULL;

	int hash, id;



	if (!host)

		return NULL;



	hash = dax_host_hash(host);



	id = dax_read_lock();

	spin_lock(&dax_host_lock);

	hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) {

		if (!dax_alive(dax_dev)

				|| strcmp(host, dax_dev->host) != 0)

			continue;



		if (igrab(&dax_dev->inode))

			found = dax_dev;

		break;

	}

	spin_unlock(&dax_host_lock);

	dax_read_unlock(id);



	return found;

}



#ifdef CONFIG_BLOCK

#include <linux/blkdev.h>
@@ -65,15 +119,13 @@ struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) 
	return dax_get_by_host(bdev->bd_disk->disk_name);

}

EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev);

#endif



bool __generic_fsdax_supported(struct dax_device *dax_dev,

bool generic_fsdax_supported(struct dax_device *dax_dev,

		struct block_device *bdev, int blocksize, sector_t start,

		sector_t sectors)

{

	bool dax_enabled = false;

	pgoff_t pgoff, pgoff_end;

	char buf[BDEVNAME_SIZE];

	void *kaddr, *end_kaddr;

	pfn_t pfn, end_pfn;

	sector_t last_page;
@@ -81,29 +133,25 @@ bool __generic_fsdax_supported(struct dax_device *dax_dev, 
	int err, id;



	if (blocksize != PAGE_SIZE) {

		pr_info("%s: error: unsupported blocksize for dax\n",

				bdevname(bdev, buf));

		pr_info("%pg: error: unsupported blocksize for dax\n", bdev);

		return false;

	}



	if (!dax_dev) {

		pr_debug("%s: error: dax unsupported by block device\n",

				bdevname(bdev, buf));

		pr_debug("%pg: error: dax unsupported by block device\n", bdev);

		return false;

	}



	err = bdev_dax_pgoff(bdev, start, PAGE_SIZE, &pgoff);

	if (err) {

		pr_info("%s: error: unaligned partition for dax\n",

				bdevname(bdev, buf));

		pr_info("%pg: error: unaligned partition for dax\n", bdev);

		return false;

	}



	last_page = PFN_DOWN((start + sectors - 1) * 512) * PAGE_SIZE / 512;

	err = bdev_dax_pgoff(bdev, last_page, PAGE_SIZE, &pgoff_end);

	if (err) {

		pr_info("%s: error: unaligned partition for dax\n",

				bdevname(bdev, buf));

		pr_info("%pg: error: unaligned partition for dax\n", bdev);

		return false;

	}
@@ -112,8 +160,8 @@ bool __generic_fsdax_supported(struct dax_device *dax_dev, 
	len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn);



	if (len < 1 || len2 < 1) {

		pr_info("%s: error: dax access failed (%ld)\n",

				bdevname(bdev, buf), len < 1 ? len : len2);

		pr_info("%pg: error: dax access failed (%ld)\n",

				bdev, len < 1 ? len : len2);

		dax_read_unlock(id);

		return false;

	}
@@ -147,57 +195,32 @@ bool __generic_fsdax_supported(struct dax_device *dax_dev, 
	dax_read_unlock(id);



	if (!dax_enabled) {

		pr_info("%s: error: dax support not enabled\n",

				bdevname(bdev, buf));

		pr_info("%pg: error: dax support not enabled\n", bdev);

		return false;

	}

	return true;

}

EXPORT_SYMBOL_GPL(__generic_fsdax_supported);

EXPORT_SYMBOL_GPL(generic_fsdax_supported);



/**

 * __bdev_dax_supported() - Check if the device supports dax for filesystem

 * @bdev: block device to check

 * @blocksize: The block size of the device

 *

 * This is a library function for filesystems to check if the block device

 * can be mounted with dax option.

 *

 * Return: true if supported, false if unsupported

 */

bool __bdev_dax_supported(struct block_device *bdev, int blocksize)

bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,

		int blocksize, sector_t start, sector_t len)

{

	struct dax_device *dax_dev;

	struct request_queue *q;

	char buf[BDEVNAME_SIZE];

	bool ret;

	bool ret = false;

	int id;



	q = bdev_get_queue(bdev);

	if (!q || !blk_queue_dax(q)) {

		pr_debug("%s: error: request queue doesn't support dax\n",

				bdevname(bdev, buf));

		return false;

	}



	dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);

	if (!dax_dev) {

		pr_debug("%s: error: device does not support dax\n",

				bdevname(bdev, buf));

	if (!dax_dev)

		return false;

	}



	id = dax_read_lock();

	ret = dax_supported(dax_dev, bdev, blocksize, 0,

			i_size_read(bdev->bd_inode) / 512);

	if (dax_alive(dax_dev) && dax_dev->ops->dax_supported)

		ret = dax_dev->ops->dax_supported(dax_dev, bdev, blocksize,

						  start, len);

	dax_read_unlock(id);



	put_dax(dax_dev);



	return ret;

}

EXPORT_SYMBOL_GPL(__bdev_dax_supported);

#endif

EXPORT_SYMBOL_GPL(dax_supported);

#endif /* CONFIG_FS_DAX */

#endif /* CONFIG_BLOCK */



enum dax_device_flags {

	/* !alive + rcu grace period == no new operations / mappings */
@@ -208,24 +231,6 @@ enum dax_device_flags { 
	DAXDEV_SYNC,

};



/**

 * struct dax_device - anchor object for dax services

 * @inode: core vfs

 * @cdev: optional character interface for "device dax"

 * @host: optional name for lookups where the device path is not available

 * @private: dax driver private data

 * @flags: state and boolean properties

 */

struct dax_device {

	struct hlist_node list;

	struct inode inode;

	struct cdev cdev;

	const char *host;

	void *private;

	unsigned long flags;

	const struct dax_operations *ops;

};



static ssize_t write_cache_show(struct device *dev,

		struct device_attribute *attr, char *buf)

{
@@ -323,19 +328,6 @@ long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 
}

EXPORT_SYMBOL_GPL(dax_direct_access);



bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,

		int blocksize, sector_t start, sector_t len)

{

	if (!dax_dev)

		return false;



	if (!dax_alive(dax_dev))

		return false;



	return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len);

}

EXPORT_SYMBOL_GPL(dax_supported);



size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,

		size_t bytes, struct iov_iter *i)

{
@@ -423,11 +415,6 @@ bool dax_alive(struct dax_device *dax_dev) 
}

EXPORT_SYMBOL_GPL(dax_alive);



static int dax_host_hash(const char *host)

{

	return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE;

}



/*

 * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring

 * that any fault handlers or operations that might have seen
@@ -624,38 +611,6 @@ void put_dax(struct dax_device *dax_dev) 
}

EXPORT_SYMBOL_GPL(put_dax);



/**

 * dax_get_by_host() - temporary lookup mechanism for filesystem-dax

 * @host: alternate name for the device registered by a dax driver

 */

struct dax_device *dax_get_by_host(const char *host)

{

	struct dax_device *dax_dev, *found = NULL;

	int hash, id;



	if (!host)

		return NULL;



	hash = dax_host_hash(host);



	id = dax_read_lock();

	spin_lock(&dax_host_lock);

	hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) {

		if (!dax_alive(dax_dev)

				|| strcmp(host, dax_dev->host) != 0)

			continue;



		if (igrab(&dax_dev->inode))

			found = dax_dev;

		break;

	}

	spin_unlock(&dax_host_lock);

	dax_read_unlock(id);



	return found;

}

EXPORT_SYMBOL_GPL(dax_get_by_host);



/**

 * inode_dax: convert a public inode into its dax_dev

 * @inode: An inode with i_cdev pointing to a dax_dev

drivers/md/dm-table.c

+2 −7
Original line number Diff line number Diff line
@@ -809,14 +809,9 @@ EXPORT_SYMBOL_GPL(dm_table_set_type); 
int device_not_dax_capable(struct dm_target *ti, struct dm_dev *dev,

			sector_t start, sector_t len, void *data)

{

	int blocksize = *(int *) data, id;

	bool rc;

	int blocksize = *(int *) data;



	id = dax_read_lock();

	rc = !dax_supported(dev->dax_dev, dev->bdev, blocksize, start, len);

	dax_read_unlock(id);



	return rc;

	return !dax_supported(dev->dax_dev, dev->bdev, blocksize, start, len);

}



/* Check devices support synchronous DAX */

drivers/md/dm.c

+1 −1
Original line number Diff line number Diff line
@@ -650,7 +650,7 @@ static int open_table_device(struct table_device *td, dev_t dev, 
	}



	td->dm_dev.bdev = bdev;

	td->dm_dev.dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);

	td->dm_dev.dax_dev = fs_dax_get_by_bdev(bdev);

	return 0;

}

fs/Kconfig

+18 −3
Original line number Diff line number Diff line
@@ -43,7 +43,7 @@ source "fs/f2fs/Kconfig" 
source "fs/zonefs/Kconfig"



config FS_DAX

	bool "Direct Access (DAX) support"

	bool "File system based Direct Access (DAX) support"

	depends on MMU

	depends on !(ARM || MIPS || SPARC)

	select DEV_PAGEMAP_OPS if (ZONE_DEVICE && !FS_DAX_LIMITED)
@@ -53,8 +53,23 @@ config FS_DAX 
	  Direct Access (DAX) can be used on memory-backed block devices.

	  If the block device supports DAX and the filesystem supports DAX,

	  then you can avoid using the pagecache to buffer I/Os.  Turning

	  on this option will compile in support for DAX; you will need to

	  mount the filesystem using the -o dax option.

	  on this option will compile in support for DAX.



	  For a DAX device to support file system access it needs to have

	  struct pages.  For the nfit based NVDIMMs this can be enabled

	  using the ndctl utility:



		# ndctl create-namespace --force --reconfig=namespace0.0 \

			--mode=fsdax --map=mem



	  See the 'create-namespace' man page for details on the overhead of

	  --map=mem:

	  https://docs.pmem.io/ndctl-user-guide/ndctl-man-pages/ndctl-create-namespace



          For ndctl to work CONFIG_DEV_DAX needs to be enabled as well. For most

	  file systems DAX support needs to be manually enabled globally or

	  per-inode using a mount option as well.  See the file documentation in

	  Documentation/filesystems/dax.rst for details.



	  If you do not have a block device that is capable of using this,

	  or if unsure, say N.  Saying Y will increase the size of the kernel

fs/ext2/super.c

+2 −1
Original line number Diff line number Diff line
@@ -949,7 +949,8 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent) 
	blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);



	if (test_opt(sb, DAX)) {

		if (!bdev_dax_supported(sb->s_bdev, blocksize)) {

		if (!dax_supported(dax_dev, sb->s_bdev, blocksize, 0,

				bdev_nr_sectors(sb->s_bdev))) {

			ext2_msg(sb, KERN_ERR,

				"DAX unsupported by block device. Turning off DAX.");

			clear_opt(sbi->s_mount_opt, DAX);