From: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
DAX relies on the get_block function either zeroing newly allocated blocks
before they're findable by subsequent calls to get_block, or marking newly
allocated blocks as unwritten. ext4_get_block() cannot create unwritten
extents, but ext4_get_block_write() can.
Reported-by: Andy Rudoff <andy.rudoff@xxxxxxxxx>
Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
---
fs/ext4/file.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 953d519..ca5302a 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -196,7 +196,7 @@ out:
static void ext4_end_io_unwritten(struct buffer_head *bh, int uptodate)
{
struct inode *inode = bh->b_assoc_map->host;
- /* XXX: breaks on 32-bit > 16GB. Is that even supported? */
+ /* XXX: breaks on 32-bit > 16TB. Is that even supported? */
loff_t offset = (loff_t)(uintptr_t)bh->b_private << inode->i_blkbits;
int err;
if (!uptodate)
@@ -207,8 +207,7 @@ static void ext4_end_io_unwritten(struct buffer_head *bh, int uptodate)
static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
- return dax_fault(vma, vmf, ext4_get_block, ext4_end_io_unwritten);
- /* Is this the right get_block? */
+ return dax_fault(vma, vmf, ext4_get_block_write, ext4_end_io_unwritten);
}
static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
@@ -220,7 +219,8 @@ static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
static int ext4_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
- return dax_mkwrite(vma, vmf, ext4_get_block, ext4_end_io_unwritten);
+ return dax_mkwrite(vma, vmf, ext4_get_block_write,
+ ext4_end_io_unwritten);
}
static const struct vm_operations_struct ext4_dax_vm_ops = {
--
2.1.4
--
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