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authorDave Chinner <dchinner@redhat.com>2015-11-03 02:37:02 +0100
committerDave Chinner <david@fromorbit.com>2015-11-03 02:37:02 +0100
commit3af49285854df66260a263198cc15abb07b95287 (patch)
tree36cf3d76bccae803a58886953be4709454a16838 /fs/xfs
parentxfs: DAX does not use IO completion callbacks (diff)
downloadlinux-3af49285854df66260a263198cc15abb07b95287.tar.xz
linux-3af49285854df66260a263198cc15abb07b95287.zip
xfs: add ->pfn_mkwrite support for DAX
->pfn_mkwrite support is needed so that when a page with allocated backing store takes a write fault we can check that the fault has not raced with a truncate and is pointing to a region beyond the current end of file. This also allows us to update the timestamp on the inode, too, which fixes a generic/080 failure. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Diffstat (limited to 'fs/xfs')
-rw-r--r--fs/xfs/xfs_file.c35
-rw-r--r--fs/xfs/xfs_trace.h1
2 files changed, 36 insertions, 0 deletions
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 9c8eef7c57b4..f429662d7d42 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1572,11 +1572,46 @@ xfs_filemap_pmd_fault(
return ret;
}
+/*
+ * pfn_mkwrite was originally inteneded to ensure we capture time stamp
+ * updates on write faults. In reality, it's need to serialise against
+ * truncate similar to page_mkwrite. Hence we open-code dax_pfn_mkwrite()
+ * here and cycle the XFS_MMAPLOCK_SHARED to ensure we serialise the fault
+ * barrier in place.
+ */
+static int
+xfs_filemap_pfn_mkwrite(
+ struct vm_area_struct *vma,
+ struct vm_fault *vmf)
+{
+
+ struct inode *inode = file_inode(vma->vm_file);
+ struct xfs_inode *ip = XFS_I(inode);
+ int ret = VM_FAULT_NOPAGE;
+ loff_t size;
+
+ trace_xfs_filemap_pfn_mkwrite(ip);
+
+ sb_start_pagefault(inode->i_sb);
+ file_update_time(vma->vm_file);
+
+ /* check if the faulting page hasn't raced with truncate */
+ xfs_ilock(ip, XFS_MMAPLOCK_SHARED);
+ size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ if (vmf->pgoff >= size)
+ ret = VM_FAULT_SIGBUS;
+ xfs_iunlock(ip, XFS_MMAPLOCK_SHARED);
+ sb_end_pagefault(inode->i_sb);
+ return ret;
+
+}
+
static const struct vm_operations_struct xfs_file_vm_ops = {
.fault = xfs_filemap_fault,
.pmd_fault = xfs_filemap_pmd_fault,
.map_pages = filemap_map_pages,
.page_mkwrite = xfs_filemap_page_mkwrite,
+ .pfn_mkwrite = xfs_filemap_pfn_mkwrite,
};
STATIC int
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 5ed36b1e04c1..c53beda675d6 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -689,6 +689,7 @@ DEFINE_INODE_EVENT(xfs_inode_free_eofblocks_invalid);
DEFINE_INODE_EVENT(xfs_filemap_fault);
DEFINE_INODE_EVENT(xfs_filemap_pmd_fault);
DEFINE_INODE_EVENT(xfs_filemap_page_mkwrite);
+DEFINE_INODE_EVENT(xfs_filemap_pfn_mkwrite);
DECLARE_EVENT_CLASS(xfs_iref_class,
TP_PROTO(struct xfs_inode *ip, unsigned long caller_ip),