[PATCH 1/2] ceph: Convert ceph_page_mkwrite() to use a folio

["Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>]

Operate on the entire folio instead of just the page.  There was an
earlier effort to do this with thp_size(), but it had the exact type
confusion between head & tail pages that folios are designed to avoid.

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
 fs/ceph/addr.c | 35 +++++++++++++++++------------------
 1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 59cbfb80edbd..5ff5ad408a2a 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1565,8 +1565,8 @@ static vm_fault_t ceph_page_mkwrite(struct vm_fault *vmf)
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct ceph_file_info *fi = vma->vm_file->private_data;
 	struct ceph_cap_flush *prealloc_cf;
-	struct page *page = vmf->page;
-	loff_t off = page_offset(page);
+	struct folio *folio = page_folio(vmf->page);
+	loff_t pos = folio_pos(folio);
 	loff_t size = i_size_read(inode);
 	size_t len;
 	int want, got, err;
@@ -1583,50 +1583,49 @@ static vm_fault_t ceph_page_mkwrite(struct vm_fault *vmf)
 	sb_start_pagefault(inode->i_sb);
 	ceph_block_sigs(&oldset);
 
-	if (off + thp_size(page) <= size)
-		len = thp_size(page);
-	else
-		len = offset_in_thp(page, size);
+	len = folio_size(folio);
+	if (pos + folio_size(folio) > size)
+		len = size - pos;
 
 	dout("page_mkwrite %p %llx.%llx %llu~%zd getting caps i_size %llu\n",
-	     inode, ceph_vinop(inode), off, len, size);
+	     inode, ceph_vinop(inode), pos, len, size);
 	if (fi->fmode & CEPH_FILE_MODE_LAZY)
 		want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
 	else
 		want = CEPH_CAP_FILE_BUFFER;
 
 	got = 0;
-	err = ceph_get_caps(vma->vm_file, CEPH_CAP_FILE_WR, want, off + len, &got);
+	err = ceph_get_caps(vma->vm_file, CEPH_CAP_FILE_WR, want, pos + len, &got);
 	if (err < 0)
 		goto out_free;
 
 	dout("page_mkwrite %p %llu~%zd got cap refs on %s\n",
-	     inode, off, len, ceph_cap_string(got));
+	     inode, pos, len, ceph_cap_string(got));
 
-	/* Update time before taking page lock */
+	/* Update time before taking folio lock */
 	file_update_time(vma->vm_file);
 	inode_inc_iversion_raw(inode);
 
 	do {
 		struct ceph_snap_context *snapc;
 
-		lock_page(page);
+		folio_lock(folio);
 
-		if (page_mkwrite_check_truncate(page, inode) < 0) {
-			unlock_page(page);
+		if (folio_mkwrite_check_truncate(folio, inode) < 0) {
+			folio_unlock(folio);
 			ret = VM_FAULT_NOPAGE;
 			break;
 		}
 
-		snapc = ceph_find_incompatible(page);
+		snapc = ceph_find_incompatible(&folio->page);
 		if (!snapc) {
-			/* success.  we'll keep the page locked. */
-			set_page_dirty(page);
+			/* success.  we'll keep the folio locked. */
+			folio_mark_dirty(folio);
 			ret = VM_FAULT_LOCKED;
 			break;
 		}
 
-		unlock_page(page);
+		folio_unlock(folio);
 
 		if (IS_ERR(snapc)) {
 			ret = VM_FAULT_SIGBUS;
@@ -1650,7 +1649,7 @@ static vm_fault_t ceph_page_mkwrite(struct vm_fault *vmf)
 	}
 
 	dout("page_mkwrite %p %llu~%zd dropping cap refs on %s ret %x\n",
-	     inode, off, len, ceph_cap_string(got), ret);
+	     inode, pos, len, ceph_cap_string(got), ret);
 	ceph_put_cap_refs_async(ci, got);
 out_free:
 	ceph_restore_sigs(&oldset);
-- 
2.40.1