Patch "ubifs: Set page uptodate in the correct place" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    ubifs: Set page uptodate in the correct place

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ubifs-set-page-uptodate-in-the-correct-place.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit ff84b88b9a0fe23cbade3cd32ed471d62eb8cd22
Author: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Date:   Wed Jan 24 17:52:44 2024 +0000

    ubifs: Set page uptodate in the correct place
    
    [ Upstream commit 723012cab779eee8228376754e22c6594229bf8f ]
    
    Page cache reads are lockless, so setting the freshly allocated page
    uptodate before we've overwritten it with the data it's supposed to have
    in it will allow a simultaneous reader to see old data.  Move the call
    to SetPageUptodate into ubifs_write_end(), which is after we copied the
    new data into the page.
    
    Fixes: 1e51764a3c2a ("UBIFS: add new flash file system")
    Cc: stable@xxxxxxxxxxxxxxx
    Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
    Reviewed-by: Zhihao Cheng <chengzhihao1@xxxxxxxxxx>
    Signed-off-by: Richard Weinberger <richard@xxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 7cc2abcb70ae8..509144cc41a0f 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -262,9 +262,6 @@ static int write_begin_slow(struct address_space *mapping,
 				return err;
 			}
 		}
-
-		SetPageUptodate(page);
-		ClearPageError(page);
 	}
 
 	if (PagePrivate(page))
@@ -463,9 +460,6 @@ static int ubifs_write_begin(struct file *file, struct address_space *mapping,
 				return err;
 			}
 		}
-
-		SetPageUptodate(page);
-		ClearPageError(page);
 	}
 
 	err = allocate_budget(c, page, ui, appending);
@@ -475,10 +469,8 @@ static int ubifs_write_begin(struct file *file, struct address_space *mapping,
 		 * If we skipped reading the page because we were going to
 		 * write all of it, then it is not up to date.
 		 */
-		if (skipped_read) {
+		if (skipped_read)
 			ClearPageChecked(page);
-			ClearPageUptodate(page);
-		}
 		/*
 		 * Budgeting failed which means it would have to force
 		 * write-back but didn't, because we set the @fast flag in the
@@ -569,6 +561,9 @@ static int ubifs_write_end(struct file *file, struct address_space *mapping,
 		goto out;
 	}
 
+	if (len == PAGE_SIZE)
+		SetPageUptodate(page);
+
 	if (!PagePrivate(page)) {
 		attach_page_private(page, (void *)1);
 		atomic_long_inc(&c->dirty_pg_cnt);