Commit 95803066 authored by Linus Torvalds's avatar Linus Torvalds

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
......@@ -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)
......
......@@ -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
......
......@@ -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);
......
......@@ -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;
......
......@@ -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");
......
......@@ -1664,8 +1664,12 @@ static int handle_mount_opt(struct super_block *sb, char *opt, int token,
}
sbi->s_jquota_fmt = m->mount_opt;
#endif
#ifndef CONFIG_FS_DAX
} else if (token == Opt_dax) {
#ifdef CONFIG_FS_DAX
ext4_msg(sb, KERN_WARNING,
"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
sbi->s_mount_opt |= m->mount_opt;
#else
ext4_msg(sb, KERN_INFO, "dax option not supported");
return -1;
#endif
......
......@@ -794,6 +794,8 @@ extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
struct scsi_ioctl_command __user *);
extern int blk_queue_enter(struct request_queue *q, gfp_t gfp);
extern void blk_queue_exit(struct request_queue *q);
extern void blk_start_queue(struct request_queue *q);
extern void blk_stop_queue(struct request_queue *q);
extern void blk_sync_queue(struct request_queue *q);
......
......@@ -3015,9 +3015,9 @@ static int do_cow_fault(struct mm_struct *mm, struct vm_area_struct *vma,
} else {
/*
* The fault handler has no page to lock, so it holds
* i_mmap_lock for write to protect against truncate.
* i_mmap_lock for read to protect against truncate.
*/
i_mmap_unlock_write(vma->vm_file->f_mapping);
i_mmap_unlock_read(vma->vm_file->f_mapping);
}
goto uncharge_out;
}
......@@ -3031,9 +3031,9 @@ static int do_cow_fault(struct mm_struct *mm, struct vm_area_struct *vma,
} else {
/*
* The fault handler has no page to lock, so it holds
* i_mmap_lock for write to protect against truncate.
* i_mmap_lock for read to protect against truncate.
*/
i_mmap_unlock_write(vma->vm_file->f_mapping);
i_mmap_unlock_read(vma->vm_file->f_mapping);
}
return ret;
uncharge_out:
......
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