mount must return EACCES, not EROFS, when one attempts to mount a
read-only filesystem in read-write mode, but the file-system layer
only transmits the error given by the block layer, and many block
drivers return EROFS in that case, so let's fix it in do_mount.
Actually it is only a small problem for a user using the mount(1)
command, because EROFS is actually a more explicit answer than
EACCES, but init/do_mounts.c checks only for EACCES, not EROFS,
to decide to retry to mount the root file-system in read-only mode,
and so we are left with an unbootable kernel, and with a cryptic
error message (*) if the root partition happens to be read-only
(*): VFS: Cannot open root device "mmcblk0p2" or unknown-block(179,2):
error -30
Signed-off-by: Philippe De Muyter <p...@macqel.be>
Cc: Al Viro <v...@zeniv.linux.org.uk>
Cc: Dave Chinner <da...@fromorbit.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: linux-fsde...@vger.kernel.org
---
fs/namespace.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/fs/namespace.c b/fs/namespace.c
index 182bc41..6291a3f 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2411,6 +2411,8 @@ long do_mount(const char *dev_name, const char *dir_name,
retval = security_sb_mount(dev_name, &path,
type_page, flags, data_page);
+ if (retval == -EROFS)
+ retval = -EACCES;
if (!retval && !may_mount())
retval = -EPERM;
if (retval)
--
1.7.5.3
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