3.16.36-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Dave Chinner <dchinner@xxxxxxxxxx>
commit 075a924d45cc69c75a35f20b4912b85aa98b180a upstream.
Take the i_mmaplock over write page faults. These come through the
->page_mkwrite callout, so we need to wrap that calls with the
i_mmaplock.
This gives us a lock order of mmap_sem -> i_mmaplock -> page_lock
-> i_lock.
Also, move the page_mkwrite wrapper to the same region of xfs_file.c
as the read fault wrappers and add a tracepoint.
Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
Signed-off-by: Dave Chinner <david@xxxxxxxxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: xfs@xxxxxxxxxxx
---
fs/xfs/xfs_file.c | 39 ++++++++++++++++++++++++---------------
fs/xfs/xfs_trace.h | 1 +
2 files changed, 25 insertions(+), 15 deletions(-)
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -957,20 +957,6 @@ xfs_file_mmap(
}
/*
- * mmap()d file has taken write protection fault and is being made
- * writable. We can set the page state up correctly for a writable
- * page, which means we can do correct delalloc accounting (ENOSPC
- * checking!) and unwritten extent mapping.
- */
-STATIC int
-xfs_vm_page_mkwrite(
- struct vm_area_struct *vma,
- struct vm_fault *vmf)
-{
- return block_page_mkwrite(vma, vmf, xfs_get_blocks);
-}
-
-/*
* This type is designed to indicate the type of offset we would like
* to search from page cache for either xfs_seek_data() or xfs_seek_hole().
*/
@@ -1443,6 +1429,29 @@ xfs_filemap_fault(
return error;
}
+/*
+ * mmap()d file has taken write protection fault and is being made writable. We
+ * can set the page state up correctly for a writable page, which means we can
+ * do correct delalloc accounting (ENOSPC checking!) and unwritten extent
+ * mapping.
+ */
+STATIC int
+xfs_filemap_page_mkwrite(
+ struct vm_area_struct *vma,
+ struct vm_fault *vmf)
+{
+ struct xfs_inode *ip = XFS_I(vma->vm_file->f_mapping->host);
+ int error;
+
+ trace_xfs_filemap_page_mkwrite(ip);
+
+ xfs_ilock(ip, XFS_MMAPLOCK_SHARED);
+ error = block_page_mkwrite(vma, vmf, xfs_get_blocks);
+ xfs_iunlock(ip, XFS_MMAPLOCK_SHARED);
+
+ return error;
+}
+
const struct file_operations xfs_file_operations = {
.llseek = xfs_file_llseek,
.read = new_sync_read,
@@ -1477,6 +1486,6 @@ const struct file_operations xfs_dir_fil
static const struct vm_operations_struct xfs_file_vm_ops = {
.fault = xfs_filemap_fault,
.map_pages = filemap_map_pages,
- .page_mkwrite = xfs_vm_page_mkwrite,
+ .page_mkwrite = xfs_filemap_page_mkwrite,
.remap_pages = generic_file_remap_pages,
};
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -685,6 +685,7 @@ DEFINE_INODE_EVENT(xfs_inode_clear_eofbl
DEFINE_INODE_EVENT(xfs_inode_free_eofblocks_invalid);
DEFINE_INODE_EVENT(xfs_filemap_fault);
+DEFINE_INODE_EVENT(xfs_filemap_page_mkwrite);
DECLARE_EVENT_CLASS(xfs_iref_class,
TP_PROTO(struct xfs_inode *ip, unsigned long caller_ip),
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