Commit 84c4e5e6 authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Linus Torvalds

dax: improve comment about truncate race

Jan Kara pointed out I should be more explicit here about the perils of
racing against truncate.  The comment is mostly the same as for the PTE
Signed-off-by: default avatarMatthew Wilcox <>
Cc: Jan Kara <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent ae18d6dc
......@@ -553,7 +553,12 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
if (!buffer_size_valid(&bh) || bh.b_size < PMD_SIZE)
goto fallback;
/* Guard against a race with truncate */
* If a truncate happened while we were allocating blocks, we may
* leave blocks allocated to the file that are beyond EOF. We can't
* take i_mutex here, so just leave them hanging; they'll be freed
* when the file is deleted.
size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
if (pgoff >= size) {
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment