Hello, On Sat 13-07-19 06:11:59, Max Kellermann wrote: > Make IS_POSIXACL() return false if POSIX ACL support is disabled and > ignore SB_POSIXACL/MS_POSIXACL. > > Never skip applying the umask in namei.c and never bother to do any > ACL specific checks if the filesystem falsely indicates it has ACLs > enabled when the feature is completely disabled in the kernel. > > This fixes a problem where the umask is always ignored in the NFS > client when compiled without CONFIG_FS_POSIX_ACL. This is a 4 year > old regression caused by commit 013cdf1088d723 which itself was not > completely wrong, but failed to consider all the side effects by > misdesigned VFS code. > > Prior to that commit, there were two places where the umask could be > applied, for example when creating a directory: > > 1. in the VFS layer in SYSCALL_DEFINE3(mkdirat), but only if > !IS_POSIXACL() > > 2. again (unconditionally) in nfs3_proc_mkdir() > > The first one does not apply, because even without > CONFIG_FS_POSIX_ACL, the NFS client sets MS_POSIXACL in > nfs_fill_super(). > > After that commit, (2.) was replaced by: > > 2b. in posix_acl_create(), called by nfs3_proc_mkdir() > > There's one branch in posix_acl_create() which applies the umask; > however, without CONFIG_FS_POSIX_ACL, posix_acl_create() is an empty > dummy function which does not apply the umask. > > The approach chosen by this patch is to make IS_POSIXACL() always > return false when POSIX ACL support is disabled, so the umask always > gets applied by the VFS layer. This is consistent with the (regular) > behavior of posix_acl_create(): that function returns early if > IS_POSIXACL() is false, before applying the umask. > > Therefore, posix_acl_create() is responsible for applying the umask if > there is ACL support enabled in the file system (SB_POSIXACL), and the > VFS layer is responsible for all other cases (no SB_POSIXACL or no > CONFIG_FS_POSIX_ACL). > > Signed-off-by: Max Kellermann <mk@xxxxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx Thanks for the patch. This patch definitely looks good to me so feel free to add: Reviewed-by: Jan Kara <jack@xxxxxxx> I just wonder, do you really need patches 1 and 2? Doesn't this patch alone fix the problem? Because AFAIU the problem, this patch should be enough and indeed the logic "VFS is responsible for applying umask if !IS_POSIXACL and otherwise posix_acl_create() is responsible for it" looks the most logical to me. BTW, I think you should add VFS maintainer - Al Viro <viro@xxxxxxxxxxxxxxxxxx> - to CC to merge the patch. Honza > --- > include/linux/fs.h | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/include/linux/fs.h b/include/linux/fs.h > index f7fdfe93e25d..5e9f3aa7ba26 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -1993,7 +1993,12 @@ static inline bool sb_rdonly(const struct super_block *sb) { return sb->s_flags > #define IS_NOQUOTA(inode) ((inode)->i_flags & S_NOQUOTA) > #define IS_APPEND(inode) ((inode)->i_flags & S_APPEND) > #define IS_IMMUTABLE(inode) ((inode)->i_flags & S_IMMUTABLE) > + > +#ifdef CONFIG_FS_POSIX_ACL > #define IS_POSIXACL(inode) __IS_FLG(inode, SB_POSIXACL) > +#else > +#define IS_POSIXACL(inode) 0 > +#endif > > #define IS_DEADDIR(inode) ((inode)->i_flags & S_DEAD) > #define IS_NOCMTIME(inode) ((inode)->i_flags & S_NOCMTIME) > -- > 2.20.1 > -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR