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From: Max Kellermann <>
Cc:, Max Kellermann <>
Subject: [PATCH 3/4] linux/fs.h: fix umask on NFS with CONFIG_FS_POSIX_ACL=n
Date: Wed,  3 Jul 2019 14:47:14 +0200	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Make IS_POSIXACL() return false if POSIX ACL support is disabled and

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

 2. again (unconditionally) in nfs3_proc_mkdir()

The first one does not apply, because even without

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

Signed-off-by: Max Kellermann <>
 include/linux/fs.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/linux/fs.h b/include/linux/fs.h
index dd28e7679089..299acdaaab56 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1985,7 +1985,12 @@ 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)
 #define IS_POSIXACL(inode)	__IS_FLG(inode, SB_POSIXACL)
+#define IS_POSIXACL(inode)	0
 #define IS_DEADDIR(inode)	((inode)->i_flags & S_DEAD)
 #define IS_NOCMTIME(inode)	((inode)->i_flags & S_NOCMTIME)

  parent reply	other threads:[~2019-07-03 12:48 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-03 12:47 [PATCH 1/4] fs/posix_acl: apply umask if superblock disables ACL support Max Kellermann
2019-07-03 12:47 ` [PATCH 2/4] fs/ext4/acl: apply umask if ACL support is disabled Max Kellermann
2019-07-03 12:47 ` Max Kellermann [this message]
2019-07-03 12:47 ` [PATCH 4/4] nfs/super: check NFS_CAP_ACLS instead of the NFS version Max Kellermann

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