NFS: nfs_async_write_reschedule_io must not recurse into the writeback code

Trond Myklebust · Trond Myklebust · commit b1a28f2eb9ea · 2022-08-02T16:03:12.000-04:00
It is not safe to call filemap_fdatawrite_range() from
nfs_async_write_reschedule_io(), since we're often calling from a page
reclaim context. Just let fsync() redrive the writeback for us.

Signed-off-by: Trond Myklebust &lt;trond.myklebust@hammerspace.com&gt;
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
@@ -1444,8 +1444,6 @@ static void nfs_async_write_error(struct list_head *head, int error)
 static void nfs_async_write_reschedule_io(struct nfs_pgio_header *hdr)
 {
 	nfs_async_write_error(&hdr->pages, 0);
-	filemap_fdatawrite_range(hdr->inode->i_mapping, hdr->args.offset,
-			hdr->args.offset + hdr->args.count - 1);
 }
 
 static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops = {

Original file line number	Diff line number	Diff line change
`@@ -1444,8 +1444,6 @@ static void nfs_async_write_error(struct list_head *head, int error)`
`1444`	`1444`	`static void nfs_async_write_reschedule_io(struct nfs_pgio_header *hdr)`
`1445`	`1445`	`{`
`1446`	`1446`	`nfs_async_write_error(&hdr->pages, 0);`
`1447`		`- filemap_fdatawrite_range(hdr->inode->i_mapping, hdr->args.offset,`
`1448`		`- hdr->args.offset + hdr->args.count - 1);`
`1449`	`1447`	`}`
`1450`	`1448`
`1451`	`1449`	`static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops = {`