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Commit 95803066 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm 

Pull libnvdimm fixes from Dan Williams:

 - A collection of crash and deadlock fixes for DAX that are also tagged
   for -stable.  We will look to re-enable DAX pmd mappings in 4.5, but
   for now 4.4 and -stable should disable it by default.

 - A fixup to ext2 and ext4 to mirror the same warning emitted by XFS
   when mounting with "-o dax"

* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  block: protect rw_page against device teardown
  mm, dax: fix DAX deadlocks (COW fault)
  dax: disable pmd mappings
  ext2, ext4: warn when mounting with dax enabled
parents 400f3f25 2e6edc95

block/blk.h

+0 −2
Original line number Diff line number Diff line
@@ -72,8 +72,6 @@ void blk_dequeue_request(struct request *rq); 
void __blk_queue_free_tags(struct request_queue *q);

bool __blk_end_bidi_request(struct request *rq, int error,

			    unsigned int nr_bytes, unsigned int bidi_bytes);

int blk_queue_enter(struct request_queue *q, gfp_t gfp);

void blk_queue_exit(struct request_queue *q);

void blk_freeze_queue(struct request_queue *q);



static inline void blk_queue_enter_live(struct request_queue *q)

fs/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -46,6 +46,12 @@ config FS_DAX 
	  or if unsure, say N.  Saying Y will increase the size of the kernel

	  by about 5kB.



config FS_DAX_PMD

	bool

	default FS_DAX

	depends on FS_DAX

	depends on BROKEN



endif # BLOCK



# Posix ACL utility routines

fs/block_dev.c

+16 −2
Original line number Diff line number Diff line
@@ -390,9 +390,17 @@ int bdev_read_page(struct block_device *bdev, sector_t sector, 
			struct page *page)

{

	const struct block_device_operations *ops = bdev->bd_disk->fops;

	int result = -EOPNOTSUPP;



	if (!ops->rw_page || bdev_get_integrity(bdev))

		return -EOPNOTSUPP;

	return ops->rw_page(bdev, sector + get_start_sect(bdev), page, READ);

		return result;



	result = blk_queue_enter(bdev->bd_queue, GFP_KERNEL);

	if (result)

		return result;

	result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, READ);

	blk_queue_exit(bdev->bd_queue);

	return result;

}

EXPORT_SYMBOL_GPL(bdev_read_page);
@@ -421,14 +429,20 @@ int bdev_write_page(struct block_device *bdev, sector_t sector, 
	int result;

	int rw = (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : WRITE;

	const struct block_device_operations *ops = bdev->bd_disk->fops;



	if (!ops->rw_page || bdev_get_integrity(bdev))

		return -EOPNOTSUPP;

	result = blk_queue_enter(bdev->bd_queue, GFP_KERNEL);

	if (result)

		return result;



	set_page_writeback(page);

	result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, rw);

	if (result)

		end_page_writeback(page);

	else

		unlock_page(page);

	blk_queue_exit(bdev->bd_queue);

	return result;

}

EXPORT_SYMBOL_GPL(bdev_write_page);

fs/dax.c

+4 −0
Original line number Diff line number Diff line
@@ -541,6 +541,10 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address, 
	unsigned long pfn;

	int result = 0;



	/* dax pmd mappings are broken wrt gup and fork */

	if (!IS_ENABLED(CONFIG_FS_DAX_PMD))

		return VM_FAULT_FALLBACK;



	/* Fall back to PTEs if we're going to COW */

	if (write && !(vma->vm_flags & VM_SHARED))

		return VM_FAULT_FALLBACK;

fs/ext2/super.c

+2 −0
Original line number Diff line number Diff line
@@ -569,6 +569,8 @@ static int parse_options(char *options, struct super_block *sb) 
			/* Fall through */

		case Opt_dax:

#ifdef CONFIG_FS_DAX

			ext2_msg(sb, KERN_WARNING,

		"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");

			set_opt(sbi->s_mount_opt, DAX);

#else

			ext2_msg(sb, KERN_INFO, "dax option not supported");