[PATCH 4.14 115/125] cachefiles: Handle readpage error correctly

Greg Kroah-Hartman
2020-11-03T21:15:08Z

From: Matthew Wilcox (Oracle) <willy@infradead.org>

commit 9480b4e75b7108ee68ecf5bc6b4bd68e8031c521 upstream.

If ->readpage returns an error, it has already unlocked the page.

Fixes: 5e929b33c393 ("CacheFiles: Handle truncate unlocking the page we're reading")
Cc: stable@vger.kernel.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/cachefiles/rdwr.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/cachefiles/rdwr.c
+++ b/fs/cachefiles/rdwr.c
@@ -125,7 +125,7 @@ static int cachefiles_read_reissue(struc
_debug("reissue read");
ret = bmapping->a_ops->readpage(NULL, backpage);
if (ret < 0)
- goto unlock_discard;
+ goto discard;
}

/* but the page may have been read before the monitor was installed, so
@@ -142,6 +142,7 @@ static int cachefiles_read_reissue(struc

unlock_discard:
unlock_page(backpage);
+discard:
spin_lock_irq(&object->work_lock);
list_del(&monitor->op_link);
spin_unlock_irq(&object->work_lock);