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authorLinus Torvalds <torvalds@linux-foundation.org>2015-11-20 15:00:50 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-20 15:00:50 -0800
commit95803066c697d40798a5db861f6152e533736a25 (patch)
treece026aede2e6e57ada85413d825cc8caff8afc1c /fs
parent400f3f255debc5a1b5eba631adddc19a9f74a6e4 (diff)
parent2e6edc95382cc36423aff18a237173ad62d5ab52 (diff)
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
Diffstat (limited to 'fs')
-rw-r--r--fs/Kconfig6
-rw-r--r--fs/block_dev.c18
-rw-r--r--fs/dax.c4
-rw-r--r--fs/ext2/super.c2
-rw-r--r--fs/ext4/super.c6
5 files changed, 33 insertions, 3 deletions
diff --git a/fs/Kconfig b/fs/Kconfig
index da3f32f1a4e4..6ce72d8d1ee1 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -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
diff --git a/fs/block_dev.c b/fs/block_dev.c
index bb0dfb1c7af1..c25639e907bd 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -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);
diff --git a/fs/dax.c b/fs/dax.c
index d1e5cb7311a1..43671b68220e 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -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;
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 3a71cea68420..748d35afc902 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -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");
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 753f4e68b820..c9ab67da6e5a 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -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