From: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
commit bb44c31cdcac107344dd2fcc3bd0504a53575c51 upstream.
This is the opposite case of kernel bugzilla 216301.
If we mmap a file using cache=none and then proceed to update the mmapped
area these updates are not reflected in a later pread() of that part of the
file.
To fix this we must first destage any dirty pages in the range before
we allow the pread() to proceed.
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Paulo Alcantara (SUSE) <pc@xxxxxx>
Reviewed-by: Enzo Matsumiya <ematsumiya@xxxxxxx>
Signed-off-by: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/cifs/file.c | 9 +++++++++
1 file changed, 9 insertions(+)
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -4024,6 +4024,15 @@ static ssize_t __cifs_readv(
len = ctx->len;
}
+ if (direct) {
+ rc = filemap_write_and_wait_range(file->f_inode->i_mapping,
+ offset, offset + len - 1);
+ if (rc) {
+ kref_put(&ctx->refcount, cifs_aio_ctx_release);
+ return -EAGAIN;
+ }
+ }
+
/* grab a lock here due to read response handlers can access ctx */
mutex_lock(&ctx->aio_mutex);
