From: Paolo Bonzini <pbonzini@redhat.com>
Date: Thu, 7 May 2015 15:45:48 +0000 (+0200)
Subject: block: return EPERM on writes or discards to read-only devices
X-Git-Tag: v2.4.0-rc0~124^2~6
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=eaf5fe2dd4ec001d645ff3b343f466457badaa64;p=thirdparty%2Fqemu.git

block: return EPERM on writes or discards to read-only devices

This is the behavior in the operating system, for example Linux's
blkdev_write_iter has the following:

        if (bdev_read_only(I_BDEV(bd_inode)))
                return -EPERM;

This does not apply to opening a device for read/write, when the
device only supports read-only operation.  In this case any of
EACCES, EPERM or EROFS is acceptable depending on why writing is
not possible.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1431013548-22492-1-git-send-email-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---

diff --git a/block/io.c b/block/io.c
index 1ce62c4fbc8..a05ad677d35 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1205,7 +1205,7 @@ static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs,
         return -ENOMEDIUM;
     }
     if (bs->read_only) {
-        return -EACCES;
+        return -EPERM;
     }
 
     ret = bdrv_check_byte_request(bs, offset, bytes);
@@ -2340,7 +2340,7 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num,
     if (ret < 0) {
         return ret;
     } else if (bs->read_only) {
-        return -EROFS;
+        return -EPERM;
     }
 
     bdrv_reset_dirty(bs, sector_num, nb_sectors);