block: check bdev_read_only() from blkdev_get()
bdev read-only status can be queried using bdev_read_only() and may
change while the device is being opened. Enforce it by checking it
from blkdev_get() after open succeeds.
This makes bdev_read_only() check in open_bdev_exclusive() and
fsg_lun_open() unnecessary. Drop them.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: linux-usb@vger.kernel.org
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 269bfbb..606a525 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1149,6 +1149,12 @@
res = __blkdev_get(bdev, mode, 0);
+ /* __blkdev_get() may alter read only status, check it afterwards */
+ if (!res && (mode & FMODE_WRITE) && bdev_read_only(bdev)) {
+ __blkdev_put(bdev, mode, 0);
+ res = -EACCES;
+ }
+
if (whole) {
/* finish claiming */
spin_lock(&bdev_lock);
@@ -1453,11 +1459,6 @@
if (error)
return ERR_PTR(error);
- if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) {
- blkdev_put(bdev, mode);
- return ERR_PTR(-EACCES);
- }
-
return bdev;
}