Commit 69456535 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'fuse-update-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse 

Pull fuse updates from Miklos Szeredi:

 - Support directly accessing host page cache from virtiofs. This can
   improve I/O performance for various workloads, as well as reducing
   the memory requirement by eliminating double caching. Thanks to Vivek
   Goyal for doing most of the work on this.

 - Allow automatic submounting inside virtiofs. This allows unique
   st_dev/ st_ino values to be assigned inside the guest to files
   residing on different filesystems on the host. Thanks to Max Reitz
   for the patches.

 - Fix an old use after free bug found by Pradeep P V K.

* tag 'fuse-update-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: (25 commits)
  virtiofs: calculate number of scatter-gather elements accurately
  fuse: connection remove fix
  fuse: implement crossmounts
  fuse: Allow fuse_fill_super_common() for submounts
  fuse: split fuse_mount off of fuse_conn
  fuse: drop fuse_conn parameter where possible
  fuse: store fuse_conn in fuse_req
  fuse: add submount support to <uapi/linux/fuse.h>
  fuse: fix page dereference after free
  virtiofs: add logic to free up a memory range
  virtiofs: maintain a list of busy elements
  virtiofs: serialize truncate/punch_hole and dax fault path
  virtiofs: define dax address space operations
  virtiofs: add DAX mmap support
  virtiofs: implement dax read/write operations
  virtiofs: introduce setupmapping/removemapping commands
  virtiofs: implement FUSE_INIT map_alignment field
  virtiofs: keep a list of free dax memory ranges
  virtiofs: add a mount option to enable dax
  virtiofs: set up virtio_fs dax_device
  ...
parents 922a763a 42d3e2d0

Documentation/filesystems/fuse.rst

+1 −1
Original line number Diff line number Diff line
@@ -47,7 +47,7 @@ filesystems. A good example is sshfs: a secure network filesystem 
using the sftp protocol.



The userspace library and utilities are available from the

`FUSE homepage: <http://fuse.sourceforge.net/>`_

`FUSE homepage: <https://github.com/libfuse/>`_



Filesystem type

===============

MAINTAINERS

+1 −1
Original line number Diff line number Diff line
@@ -7238,7 +7238,7 @@ FUSE: FILESYSTEM IN USERSPACE 
M:	Miklos Szeredi <miklos@szeredi.hu>

L:	linux-fsdevel@vger.kernel.org

S:	Maintained

W:	http://fuse.sourceforge.net/

W:	https://github.com/libfuse/

T:	git git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse.git

F:	Documentation/filesystems/fuse.rst

F:	fs/fuse/

drivers/dax/super.c

+2 −1
Original line number Diff line number Diff line
@@ -46,7 +46,8 @@ EXPORT_SYMBOL_GPL(dax_read_unlock); 
int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size,

		pgoff_t *pgoff)

{

	phys_addr_t phys_off = (get_start_sect(bdev) + sector) * 512;

	sector_t start_sect = bdev ? get_start_sect(bdev) : 0;

	phys_addr_t phys_off = (start_sect + sector) * 512;



	if (pgoff)

		*pgoff = PHYS_PFN(phys_off);

fs/dax.c

+23 −6
Original line number Diff line number Diff line
@@ -559,8 +559,11 @@ fallback: 
}



/**

 * dax_layout_busy_page - find first pinned page in @mapping

 * dax_layout_busy_page_range - find first pinned page in @mapping

 * @mapping: address space to scan for a page with ref count > 1

 * @start: Starting offset. Page containing 'start' is included.

 * @end: End offset. Page containing 'end' is included. If 'end' is LLONG_MAX,

 *       pages from 'start' till the end of file are included.

 *

 * DAX requires ZONE_DEVICE mapped pages. These pages are never

 * 'onlined' to the page allocator so they are considered idle when
@@ -573,12 +576,15 @@ fallback: 
 * to be able to run unmap_mapping_range() and subsequently not race

 * mapping_mapped() becoming true.

 */

struct page *dax_layout_busy_page(struct address_space *mapping)

struct page *dax_layout_busy_page_range(struct address_space *mapping,

					loff_t start, loff_t end)

{

	XA_STATE(xas, &mapping->i_pages, 0);

	void *entry;

	unsigned int scanned = 0;

	struct page *page = NULL;

	pgoff_t start_idx = start >> PAGE_SHIFT;

	pgoff_t end_idx;

	XA_STATE(xas, &mapping->i_pages, start_idx);



	/*

	 * In the 'limited' case get_user_pages() for dax is disabled.
@@ -589,6 +595,11 @@ struct page *dax_layout_busy_page(struct address_space *mapping) 
	if (!dax_mapping(mapping) || !mapping_mapped(mapping))

		return NULL;



	/* If end == LLONG_MAX, all pages from start to till end of file */

	if (end == LLONG_MAX)

		end_idx = ULONG_MAX;

	else

		end_idx = end >> PAGE_SHIFT;

	/*

	 * If we race get_user_pages_fast() here either we'll see the

	 * elevated page count in the iteration and wait, or
@@ -596,15 +607,15 @@ struct page *dax_layout_busy_page(struct address_space *mapping) 
	 * against is no longer mapped in the page tables and bail to the

	 * get_user_pages() slow path.  The slow path is protected by

	 * pte_lock() and pmd_lock(). New references are not taken without

	 * holding those locks, and unmap_mapping_range() will not zero the

	 * holding those locks, and unmap_mapping_pages() will not zero the

	 * pte or pmd without holding the respective lock, so we are

	 * guaranteed to either see new references or prevent new

	 * references from being established.

	 */

	unmap_mapping_range(mapping, 0, 0, 0);

	unmap_mapping_pages(mapping, start_idx, end_idx - start_idx + 1, 0);



	xas_lock_irq(&xas);

	xas_for_each(&xas, entry, ULONG_MAX) {

	xas_for_each(&xas, entry, end_idx) {

		if (WARN_ON_ONCE(!xa_is_value(entry)))

			continue;

		if (unlikely(dax_is_locked(entry)))
@@ -625,6 +636,12 @@ struct page *dax_layout_busy_page(struct address_space *mapping) 
	xas_unlock_irq(&xas);

	return page;

}

EXPORT_SYMBOL_GPL(dax_layout_busy_page_range);



struct page *dax_layout_busy_page(struct address_space *mapping)

{

	return dax_layout_busy_page_range(mapping, 0, LLONG_MAX);

}

EXPORT_SYMBOL_GPL(dax_layout_busy_page);



static int __dax_invalidate_entry(struct address_space *mapping,

fs/fuse/Kconfig

+15 −1
Original line number Diff line number Diff line
@@ -8,7 +8,7 @@ config FUSE_FS 


	  There's also a companion library: libfuse2.  This library is available

	  from the FUSE homepage:

	  <http://fuse.sourceforge.net/>

	  <https://github.com/libfuse/>

	  although chances are your distribution already has that library

	  installed if you've installed the "fuse" package itself.
@@ -38,3 +38,17 @@ config VIRTIO_FS 


	  If you want to share files between guests or with the host, answer Y

	  or M.



config FUSE_DAX

	bool "Virtio Filesystem Direct Host Memory Access support"

	default y

	select INTERVAL_TREE

	depends on VIRTIO_FS

	depends on FS_DAX

	depends on DAX_DRIVER

	help

	  This allows bypassing guest page cache and allows mapping host page

	  cache directly in guest address space.



	  If you want to allow mounting a Virtio Filesystem with the "dax"

	  option, answer Y.

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