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@vger.kernel.org Signed-off-by: Matthew Wilcox (Oracle) willy@infradead.org --- fs/ubifs/file.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c index 5029eb3390a5..40a9b03ef821 100644 --- a/fs/ubifs/file.c +++ b/fs/ubifs/file.c @@ -463,9 +463,6 @@ 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); @@ -569,6 +566,9 @@ 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);