linux/fs/overlayfs
hujianyang 71cbad7e69 ovl: upper fs should not be R/O
After importing multi-lower layer support, users could mount a r/o
partition as the left most lowerdir instead of using it as upperdir.
And a r/o upperdir may cause an error like

	overlayfs: failed to create directory ./workdir/work

during mount.

This patch check the *s_flags* of upper fs and return an error if
it is a r/o partition. The checking of *upper_mnt->mnt_sb->s_flags*
can be removed now.

This patch also remove

	/* FIXME: workdir is not needed for a R/O mount */

from ovl_fill_super() because:

1) for upper fs r/o case
Setting a r/o partition as upper is prevented, no need to care about
workdir in this case.

2) for "mount overlay -o ro" with a r/w upper fs case
Users could remount overlayfs to r/w in this case, so workdir should
not be omitted.

Signed-off-by: hujianyang <hujianyang@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2015-03-18 10:29:48 +01:00
..
Kconfig ovl: rename filesystem type to "overlay" 2014-11-20 16:39:59 +01:00
Makefile ovl: rename filesystem type to "overlay" 2014-11-20 16:39:59 +01:00
copy_up.c ovl: Cleanup redundant blank lines 2014-12-13 00:59:52 +01:00
dir.c VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry) 2015-02-22 11:38:41 -05:00
inode.c ovl: Use macros to present ovl_xattr 2014-12-13 00:59:52 +01:00
overlayfs.h ovl: Use macros to present ovl_xattr 2014-12-13 00:59:52 +01:00
readdir.c Merge branch 'overlayfs-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs into for-next 2015-02-20 04:58:52 -05:00
super.c ovl: upper fs should not be R/O 2015-03-18 10:29:48 +01:00