From: Miklos Szeredi <mszeredi@redhat.com>
Date: Wed, 14 Apr 2021 08:40:56 +0000 (+0200)
Subject: fuse: don't zero pages twice
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a73d47f57792dc3140348cc07271500c610b5624;p=linux.git

fuse: don't zero pages twice

All callers of fuse_short_read already set the .page_zeroing flag, so no
need to do the tail zeroing again.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index eff4abaa87da0..51187777c39bc 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -798,21 +798,12 @@ static void fuse_short_read(struct inode *inode, u64 attr_ver, size_t num_read,
 {
 	struct fuse_conn *fc = get_fuse_conn(inode);
 
-	if (fc->writeback_cache) {
-		/*
-		 * A hole in a file. Some data after the hole are in page cache,
-		 * but have not reached the client fs yet. So, the hole is not
-		 * present there.
-		 */
-		int i;
-		int start_idx = num_read >> PAGE_SHIFT;
-		size_t off = num_read & (PAGE_SIZE - 1);
-
-		for (i = start_idx; i < ap->num_pages; i++) {
-			zero_user_segment(ap->pages[i], off, PAGE_SIZE);
-			off = 0;
-		}
-	} else {
+	/*
+	 * If writeback_cache is enabled, a short read means there's a hole in
+	 * the file.  Some data after the hole is in page cache, but has not
+	 * reached the client fs yet.  So the hole is not present there.
+	 */
+	if (!fc->writeback_cache) {
 		loff_t pos = page_offset(ap->pages[0]) + num_read;
 		fuse_read_update_size(inode, pos, attr_ver);
 	}